1 /*-
2 * SPDX-License-Identifier: BSD-3-Clause
3 *
4 * Copyright (c) 1982, 1986, 1989, 1991, 1993
5 * The Regents of the University of California. All rights reserved.
6 * (c) UNIX System Laboratories, Inc.
7 * All or some portions of this file are derived from material licensed
8 * to the University of California by American Telephone and Telegraph
9 * Co. or Unix System Laboratories, Inc. and are reproduced herein with
10 * the permission of UNIX System Laboratories, Inc.
11 *
12 * Redistribution and use in source and binary forms, with or without
13 * modification, are permitted provided that the following conditions
14 * are met:
15 * 1. Redistributions of source code must retain the above copyright
16 * notice, this list of conditions and the following disclaimer.
17 * 2. Redistributions in binary form must reproduce the above copyright
18 * notice, this list of conditions and the following disclaimer in the
19 * documentation and/or other materials provided with the distribution.
20 * 3. Neither the name of the University nor the names of its contributors
21 * may be used to endorse or promote products derived from this software
22 * without specific prior written permission.
23 *
24 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
25 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
26 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
27 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
28 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
29 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
30 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
31 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
32 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
33 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
34 * SUCH DAMAGE.
35 */
36
37 #include "opt_capsicum.h"
38 #include "opt_ddb.h"
39 #include "opt_ktrace.h"
40
41 #define EXTERR_CATEGORY EXTERR_CAT_FILEDESC
42 #include <sys/systm.h>
43 #include <sys/capsicum.h>
44 #include <sys/conf.h>
45 #include <sys/exterrvar.h>
46 #include <sys/fcntl.h>
47 #include <sys/file.h>
48 #include <sys/filedesc.h>
49 #include <sys/filio.h>
50 #include <sys/jail.h>
51 #include <sys/kernel.h>
52 #include <sys/limits.h>
53 #include <sys/lock.h>
54 #include <sys/malloc.h>
55 #include <sys/mount.h>
56 #include <sys/mutex.h>
57 #include <sys/namei.h>
58 #include <sys/selinfo.h>
59 #include <sys/poll.h>
60 #include <sys/priv.h>
61 #include <sys/proc.h>
62 #include <sys/protosw.h>
63 #include <sys/racct.h>
64 #include <sys/resourcevar.h>
65 #include <sys/sbuf.h>
66 #include <sys/signalvar.h>
67 #include <sys/kdb.h>
68 #include <sys/smr.h>
69 #include <sys/stat.h>
70 #include <sys/sx.h>
71 #include <sys/syscallsubr.h>
72 #include <sys/sysctl.h>
73 #include <sys/sysproto.h>
74 #include <sys/unistd.h>
75 #include <sys/user.h>
76 #include <sys/vnode.h>
77 #include <sys/ktrace.h>
78
79 #include <net/vnet.h>
80
81 #include <security/audit/audit.h>
82
83 #include <vm/uma.h>
84 #include <vm/vm.h>
85
86 #include <ddb/ddb.h>
87
88 static MALLOC_DEFINE(M_FILEDESC, "filedesc", "Open file descriptor table");
89 static MALLOC_DEFINE(M_PWD, "pwd", "Descriptor table vnodes");
90 static MALLOC_DEFINE(M_PWDDESC, "pwddesc", "Pwd descriptors");
91 static MALLOC_DEFINE(M_FILEDESC_TO_LEADER, "filedesc_to_leader",
92 "file desc to leader structures");
93 static MALLOC_DEFINE(M_SIGIO, "sigio", "sigio structures");
94 MALLOC_DEFINE(M_FILECAPS, "filecaps", "descriptor capabilities");
95
96 MALLOC_DECLARE(M_FADVISE);
97
98 static __read_mostly uma_zone_t file_zone;
99 static __read_mostly uma_zone_t filedesc0_zone;
100 __read_mostly uma_zone_t pwd_zone;
101 VFS_SMR_DECLARE;
102
103 static int closefp(struct filedesc *fdp, int fd, struct file *fp,
104 struct thread *td, bool holdleaders, bool audit);
105 static void export_file_to_kinfo(struct file *fp, int fd,
106 cap_rights_t *rightsp, struct kinfo_file *kif,
107 struct filedesc *fdp, int flags);
108 static int fd_first_free(struct filedesc *fdp, int low, int size);
109 static void fdgrowtable(struct filedesc *fdp, int nfd);
110 static void fdgrowtable_exp(struct filedesc *fdp, int nfd);
111 static void fdunused(struct filedesc *fdp, int fd);
112 static void fdused(struct filedesc *fdp, int fd);
113 static int fget_unlocked_seq(struct thread *td, int fd,
114 const cap_rights_t *needrightsp, uint8_t *flagsp,
115 struct file **fpp, seqc_t *seqp);
116 static int getmaxfd(struct thread *td);
117 static u_long *filecaps_copy_prep(const struct filecaps *src);
118 static void filecaps_copy_finish(const struct filecaps *src,
119 struct filecaps *dst, u_long *ioctls);
120 static u_long *filecaps_free_prep(struct filecaps *fcaps);
121 static void filecaps_free_finish(u_long *ioctls);
122
123 static struct pwd *pwd_alloc(void);
124
125 /*
126 * Each process has:
127 *
128 * - An array of open file descriptors (fd_ofiles)
129 * - An array of file flags (fd_ofileflags)
130 * - A bitmap recording which descriptors are in use (fd_map)
131 *
132 * A process starts out with NDFILE descriptors. The value of NDFILE has
133 * been selected based the historical limit of 20 open files, and an
134 * assumption that the majority of processes, especially short-lived
135 * processes like shells, will never need more.
136 *
137 * If this initial allocation is exhausted, a larger descriptor table and
138 * map are allocated dynamically, and the pointers in the process's struct
139 * filedesc are updated to point to those. This is repeated every time
140 * the process runs out of file descriptors (provided it hasn't hit its
141 * resource limit).
142 *
143 * Since threads may hold references to individual descriptor table
144 * entries, the tables are never freed. Instead, they are placed on a
145 * linked list and freed only when the struct filedesc is released.
146 */
147 #define NDFILE 20
148 #define NDSLOTSIZE sizeof(NDSLOTTYPE)
149 #define NDENTRIES (NDSLOTSIZE * __CHAR_BIT)
150 #define NDSLOT(x) ((x) / NDENTRIES)
151 #define NDBIT(x) ((NDSLOTTYPE)1 << ((x) % NDENTRIES))
152 #define NDSLOTS(x) (((x) + NDENTRIES - 1) / NDENTRIES)
153
154 #define FILEDESC_FOREACH_FDE(fdp, _iterator, _fde) \
155 struct filedesc *_fdp = (fdp); \
156 int _lastfile = fdlastfile_single(_fdp); \
157 for (_iterator = 0; _iterator <= _lastfile; _iterator++) \
158 if ((_fde = &_fdp->fd_ofiles[_iterator])->fde_file != NULL)
159
160 #define FILEDESC_FOREACH_FP(fdp, _iterator, _fp) \
161 struct filedesc *_fdp = (fdp); \
162 int _lastfile = fdlastfile_single(_fdp); \
163 for (_iterator = 0; _iterator <= _lastfile; _iterator++) \
164 if ((_fp = _fdp->fd_ofiles[_iterator].fde_file) != NULL)
165
166 /*
167 * SLIST entry used to keep track of ofiles which must be reclaimed when
168 * the process exits.
169 */
170 struct freetable {
171 struct fdescenttbl *ft_table;
172 SLIST_ENTRY(freetable) ft_next;
173 };
174
175 /*
176 * Initial allocation: a filedesc structure + the head of SLIST used to
177 * keep track of old ofiles + enough space for NDFILE descriptors.
178 */
179
180 struct fdescenttbl0 {
181 int fdt_nfiles;
182 struct filedescent fdt_ofiles[NDFILE];
183 };
184
185 struct filedesc0 {
186 struct filedesc fd_fd;
187 SLIST_HEAD(, freetable) fd_free;
188 struct fdescenttbl0 fd_dfiles;
189 NDSLOTTYPE fd_dmap[NDSLOTS(NDFILE)];
190 };
191
192 /*
193 * Descriptor management.
194 */
195 static int __exclusive_cache_line openfiles; /* actual number of open files */
196 struct mtx sigio_lock; /* mtx to protect pointers to sigio */
197
198 /*
199 * If low >= size, just return low. Otherwise find the first zero bit in the
200 * given bitmap, starting at low and not exceeding size - 1. Return size if
201 * not found.
202 */
203 static int
fd_first_free(struct filedesc * fdp,int low,int size)204 fd_first_free(struct filedesc *fdp, int low, int size)
205 {
206 NDSLOTTYPE *map = fdp->fd_map;
207 NDSLOTTYPE mask;
208 int off, maxoff;
209
210 if (low >= size)
211 return (low);
212
213 off = NDSLOT(low);
214 if (low % NDENTRIES) {
215 mask = ~(~(NDSLOTTYPE)0 >> (NDENTRIES - (low % NDENTRIES)));
216 if ((mask &= ~map[off]) != 0UL)
217 return (off * NDENTRIES + ffsl(mask) - 1);
218 ++off;
219 }
220 for (maxoff = NDSLOTS(size); off < maxoff; ++off)
221 if (map[off] != ~0UL)
222 return (off * NDENTRIES + ffsl(~map[off]) - 1);
223 return (size);
224 }
225
226 /*
227 * Find the last used fd.
228 *
229 * Call this variant if fdp can't be modified by anyone else (e.g, during exec).
230 * Otherwise use fdlastfile.
231 */
232 int
fdlastfile_single(struct filedesc * fdp)233 fdlastfile_single(struct filedesc *fdp)
234 {
235 NDSLOTTYPE *map = fdp->fd_map;
236 int off, minoff;
237
238 off = NDSLOT(fdp->fd_nfiles - 1);
239 for (minoff = NDSLOT(0); off >= minoff; --off)
240 if (map[off] != 0)
241 return (off * NDENTRIES + flsl(map[off]) - 1);
242 return (-1);
243 }
244
245 int
fdlastfile(struct filedesc * fdp)246 fdlastfile(struct filedesc *fdp)
247 {
248
249 FILEDESC_LOCK_ASSERT(fdp);
250 return (fdlastfile_single(fdp));
251 }
252
253 static int
fdisused(struct filedesc * fdp,int fd)254 fdisused(struct filedesc *fdp, int fd)
255 {
256
257 KASSERT(fd >= 0 && fd < fdp->fd_nfiles,
258 ("file descriptor %d out of range (0, %d)", fd, fdp->fd_nfiles));
259
260 return ((fdp->fd_map[NDSLOT(fd)] & NDBIT(fd)) != 0);
261 }
262
263 /*
264 * Mark a file descriptor as used.
265 */
266 static void
fdused_init(struct filedesc * fdp,int fd)267 fdused_init(struct filedesc *fdp, int fd)
268 {
269
270 KASSERT(!fdisused(fdp, fd), ("fd=%d is already used", fd));
271
272 fdp->fd_map[NDSLOT(fd)] |= NDBIT(fd);
273 }
274
275 static void
fdused(struct filedesc * fdp,int fd)276 fdused(struct filedesc *fdp, int fd)
277 {
278
279 FILEDESC_XLOCK_ASSERT(fdp);
280
281 fdused_init(fdp, fd);
282 if (fd == fdp->fd_freefile)
283 fdp->fd_freefile++;
284 }
285
286 /*
287 * Mark a file descriptor as unused.
288 */
289 static void
fdunused(struct filedesc * fdp,int fd)290 fdunused(struct filedesc *fdp, int fd)
291 {
292
293 FILEDESC_XLOCK_ASSERT(fdp);
294
295 KASSERT(fdisused(fdp, fd), ("fd=%d is already unused", fd));
296 KASSERT(fdp->fd_ofiles[fd].fde_file == NULL,
297 ("fd=%d is still in use", fd));
298
299 fdp->fd_map[NDSLOT(fd)] &= ~NDBIT(fd);
300 if (fd < fdp->fd_freefile)
301 fdp->fd_freefile = fd;
302 }
303
304 /*
305 * Free a file descriptor.
306 *
307 * Avoid some work if fdp is about to be destroyed.
308 */
309 static inline void
fdefree_last(struct filedescent * fde)310 fdefree_last(struct filedescent *fde)
311 {
312
313 filecaps_free(&fde->fde_caps);
314 }
315
316 static inline void
fdfree(struct filedesc * fdp,int fd)317 fdfree(struct filedesc *fdp, int fd)
318 {
319 struct filedescent *fde;
320
321 FILEDESC_XLOCK_ASSERT(fdp);
322 fde = &fdp->fd_ofiles[fd];
323 #ifdef CAPABILITIES
324 seqc_write_begin(&fde->fde_seqc);
325 #endif
326 fde->fde_file = NULL;
327 #ifdef CAPABILITIES
328 seqc_write_end(&fde->fde_seqc);
329 #endif
330 fdefree_last(fde);
331 fdunused(fdp, fd);
332 }
333
334 /*
335 * System calls on descriptors.
336 */
337 #ifndef _SYS_SYSPROTO_H_
338 struct getdtablesize_args {
339 int dummy;
340 };
341 #endif
342 /* ARGSUSED */
343 int
sys_getdtablesize(struct thread * td,struct getdtablesize_args * uap)344 sys_getdtablesize(struct thread *td, struct getdtablesize_args *uap)
345 {
346 #ifdef RACCT
347 uint64_t lim;
348 #endif
349
350 td->td_retval[0] = getmaxfd(td);
351 #ifdef RACCT
352 PROC_LOCK(td->td_proc);
353 lim = racct_get_limit(td->td_proc, RACCT_NOFILE);
354 PROC_UNLOCK(td->td_proc);
355 if (lim < td->td_retval[0])
356 td->td_retval[0] = lim;
357 #endif
358 return (0);
359 }
360
361 /*
362 * Duplicate a file descriptor to a particular value.
363 *
364 * Note: keep in mind that a potential race condition exists when closing
365 * descriptors from a shared descriptor table (via rfork).
366 */
367 #ifndef _SYS_SYSPROTO_H_
368 struct dup2_args {
369 u_int from;
370 u_int to;
371 };
372 #endif
373 /* ARGSUSED */
374 int
sys_dup2(struct thread * td,struct dup2_args * uap)375 sys_dup2(struct thread *td, struct dup2_args *uap)
376 {
377
378 return (kern_dup(td, FDDUP_FIXED, 0, (int)uap->from, (int)uap->to));
379 }
380
381 /*
382 * Duplicate a file descriptor.
383 */
384 #ifndef _SYS_SYSPROTO_H_
385 struct dup_args {
386 u_int fd;
387 };
388 #endif
389 /* ARGSUSED */
390 int
sys_dup(struct thread * td,struct dup_args * uap)391 sys_dup(struct thread *td, struct dup_args *uap)
392 {
393
394 return (kern_dup(td, FDDUP_NORMAL, 0, (int)uap->fd, 0));
395 }
396
397 /*
398 * The file control system call.
399 */
400 #ifndef _SYS_SYSPROTO_H_
401 struct fcntl_args {
402 int fd;
403 int cmd;
404 long arg;
405 };
406 #endif
407 /* ARGSUSED */
408 int
sys_fcntl(struct thread * td,struct fcntl_args * uap)409 sys_fcntl(struct thread *td, struct fcntl_args *uap)
410 {
411
412 return (kern_fcntl_freebsd(td, uap->fd, uap->cmd, uap->arg));
413 }
414
415 int
kern_fcntl_freebsd(struct thread * td,int fd,int cmd,intptr_t arg)416 kern_fcntl_freebsd(struct thread *td, int fd, int cmd, intptr_t arg)
417 {
418 struct flock fl;
419 struct __oflock ofl;
420 intptr_t arg1;
421 int error, newcmd;
422
423 error = 0;
424 newcmd = cmd;
425 switch (cmd) {
426 case F_OGETLK:
427 case F_OSETLK:
428 case F_OSETLKW:
429 /*
430 * Convert old flock structure to new.
431 */
432 error = copyin((void *)arg, &ofl, sizeof(ofl));
433 fl.l_start = ofl.l_start;
434 fl.l_len = ofl.l_len;
435 fl.l_pid = ofl.l_pid;
436 fl.l_type = ofl.l_type;
437 fl.l_whence = ofl.l_whence;
438 fl.l_sysid = 0;
439
440 switch (cmd) {
441 case F_OGETLK:
442 newcmd = F_GETLK;
443 break;
444 case F_OSETLK:
445 newcmd = F_SETLK;
446 break;
447 case F_OSETLKW:
448 newcmd = F_SETLKW;
449 break;
450 }
451 arg1 = (intptr_t)&fl;
452 break;
453 case F_GETLK:
454 case F_SETLK:
455 case F_SETLKW:
456 case F_SETLK_REMOTE:
457 error = copyin((void *)arg, &fl, sizeof(fl));
458 arg1 = (intptr_t)&fl;
459 break;
460 default:
461 arg1 = arg;
462 break;
463 }
464 if (error)
465 return (error);
466 error = kern_fcntl(td, fd, newcmd, arg1);
467 if (error)
468 return (error);
469 if (cmd == F_OGETLK) {
470 ofl.l_start = fl.l_start;
471 ofl.l_len = fl.l_len;
472 ofl.l_pid = fl.l_pid;
473 ofl.l_type = fl.l_type;
474 ofl.l_whence = fl.l_whence;
475 error = copyout(&ofl, (void *)arg, sizeof(ofl));
476 } else if (cmd == F_GETLK) {
477 error = copyout(&fl, (void *)arg, sizeof(fl));
478 }
479 return (error);
480 }
481
482 struct flags_trans_elem {
483 u_int f;
484 u_int t;
485 };
486
487 static u_int
flags_trans(const struct flags_trans_elem * ftes,int nitems,u_int from_flags)488 flags_trans(const struct flags_trans_elem *ftes, int nitems, u_int from_flags)
489 {
490 u_int res;
491 int i;
492
493 res = 0;
494 for (i = 0; i < nitems; i++) {
495 if ((from_flags & ftes[i].f) != 0)
496 res |= ftes[i].t;
497 }
498 return (res);
499 }
500
501 static uint8_t
fd_to_fde_flags(int fd_flags)502 fd_to_fde_flags(int fd_flags)
503 {
504 static const struct flags_trans_elem fd_to_fde_flags_s[] = {
505 { .f = FD_CLOEXEC, .t = UF_EXCLOSE },
506 { .f = FD_CLOFORK, .t = UF_FOCLOSE },
507 { .f = FD_RESOLVE_BENEATH, .t = UF_RESOLVE_BENEATH },
508 };
509
510 return (flags_trans(fd_to_fde_flags_s, nitems(fd_to_fde_flags_s),
511 fd_flags));
512 }
513
514 static int
fde_to_fd_flags(uint8_t fde_flags)515 fde_to_fd_flags(uint8_t fde_flags)
516 {
517 static const struct flags_trans_elem fde_to_fd_flags_s[] = {
518 { .f = UF_EXCLOSE, .t = FD_CLOEXEC },
519 { .f = UF_FOCLOSE, .t = FD_CLOFORK },
520 { .f = UF_RESOLVE_BENEATH, .t = FD_RESOLVE_BENEATH },
521 };
522
523 return (flags_trans(fde_to_fd_flags_s, nitems(fde_to_fd_flags_s),
524 fde_flags));
525 }
526
527 static uint8_t
fddup_to_fde_flags(int fddup_flags)528 fddup_to_fde_flags(int fddup_flags)
529 {
530 static const struct flags_trans_elem fddup_to_fde_flags_s[] = {
531 { .f = FDDUP_FLAG_CLOEXEC, .t = UF_EXCLOSE },
532 { .f = FDDUP_FLAG_CLOFORK, .t = UF_FOCLOSE },
533 };
534
535 return (flags_trans(fddup_to_fde_flags_s, nitems(fddup_to_fde_flags_s),
536 fddup_flags));
537 }
538
539 static uint8_t
close_range_to_fde_flags(int close_range_flags)540 close_range_to_fde_flags(int close_range_flags)
541 {
542 static const struct flags_trans_elem close_range_to_fde_flags_s[] = {
543 { .f = CLOSE_RANGE_CLOEXEC, .t = UF_EXCLOSE },
544 { .f = CLOSE_RANGE_CLOFORK, .t = UF_FOCLOSE },
545 };
546
547 return (flags_trans(close_range_to_fde_flags_s,
548 nitems(close_range_to_fde_flags_s), close_range_flags));
549 }
550
551 static uint8_t
open_to_fde_flags(int open_flags,bool sticky_orb)552 open_to_fde_flags(int open_flags, bool sticky_orb)
553 {
554 static const struct flags_trans_elem open_to_fde_flags_s[] = {
555 { .f = O_CLOEXEC, .t = UF_EXCLOSE },
556 { .f = O_CLOFORK, .t = UF_FOCLOSE },
557 { .f = O_RESOLVE_BENEATH, .t = UF_RESOLVE_BENEATH },
558 };
559 #if defined(__clang__) && __clang_major__ >= 19
560 _Static_assert(open_to_fde_flags_s[nitems(open_to_fde_flags_s) - 1].f ==
561 O_RESOLVE_BENEATH, "O_RESOLVE_BENEATH must be last, for sticky_orb");
562 #endif
563
564 return (flags_trans(open_to_fde_flags_s, nitems(open_to_fde_flags_s) -
565 (sticky_orb ? 0 : 1), open_flags));
566 }
567
568 int
kern_fcntl(struct thread * td,int fd,int cmd,intptr_t arg)569 kern_fcntl(struct thread *td, int fd, int cmd, intptr_t arg)
570 {
571 struct filedesc *fdp;
572 struct flock *flp;
573 struct file *fp, *fp2;
574 struct filedescent *fde;
575 struct proc *p;
576 struct vnode *vp;
577 struct mount *mp;
578 struct kinfo_file *kif;
579 int error, flg, kif_sz, seals, tmp, got_set, got_cleared;
580 uint64_t bsize;
581 off_t foffset;
582 int flags;
583
584 error = 0;
585 flg = F_POSIX;
586 p = td->td_proc;
587 fdp = p->p_fd;
588
589 AUDIT_ARG_FD(cmd);
590 AUDIT_ARG_CMD(cmd);
591 switch (cmd) {
592 case F_DUPFD:
593 tmp = arg;
594 error = kern_dup(td, FDDUP_FCNTL, 0, fd, tmp);
595 break;
596
597 case F_DUPFD_CLOEXEC:
598 tmp = arg;
599 error = kern_dup(td, FDDUP_FCNTL, FDDUP_FLAG_CLOEXEC, fd, tmp);
600 break;
601
602 case F_DUPFD_CLOFORK:
603 tmp = arg;
604 error = kern_dup(td, FDDUP_FCNTL, FDDUP_FLAG_CLOFORK, fd, tmp);
605 break;
606
607 case F_DUP2FD:
608 tmp = arg;
609 error = kern_dup(td, FDDUP_FIXED, 0, fd, tmp);
610 break;
611
612 case F_DUP2FD_CLOEXEC:
613 tmp = arg;
614 error = kern_dup(td, FDDUP_FIXED, FDDUP_FLAG_CLOEXEC, fd, tmp);
615 break;
616
617 case F_GETFD:
618 error = EBADF;
619 FILEDESC_SLOCK(fdp);
620 fde = fdeget_noref(fdp, fd);
621 if (fde != NULL) {
622 td->td_retval[0] = fde_to_fd_flags(fde->fde_flags);
623 error = 0;
624 }
625 FILEDESC_SUNLOCK(fdp);
626 break;
627
628 case F_SETFD:
629 error = EBADF;
630 FILEDESC_XLOCK(fdp);
631 fde = fdeget_noref(fdp, fd);
632 if (fde != NULL) {
633 /*
634 * UF_RESOLVE_BENEATH is sticky and cannot be cleared.
635 */
636 fde->fde_flags = (fde->fde_flags &
637 ~(UF_EXCLOSE | UF_FOCLOSE)) | fd_to_fde_flags(arg);
638 error = 0;
639 }
640 FILEDESC_XUNLOCK(fdp);
641 break;
642
643 case F_GETFL:
644 error = fget_fcntl(td, fd, &cap_fcntl_rights, F_GETFL, &fp);
645 if (error != 0)
646 break;
647 td->td_retval[0] = OFLAGS(fp->f_flag);
648 fdrop(fp, td);
649 break;
650
651 case F_SETFL:
652 error = fget_fcntl(td, fd, &cap_fcntl_rights, F_SETFL, &fp);
653 if (error != 0)
654 break;
655 if (fp->f_ops == &path_fileops) {
656 fdrop(fp, td);
657 error = EBADF;
658 break;
659 }
660 fsetfl_lock(fp);
661 do {
662 tmp = flg = fp->f_flag;
663 tmp &= ~FCNTLFLAGS;
664 tmp |= FFLAGS(arg & ~O_ACCMODE) & FCNTLFLAGS;
665 } while (atomic_cmpset_int(&fp->f_flag, flg, tmp) == 0);
666 got_set = tmp & ~flg;
667 got_cleared = flg & ~tmp;
668 if (((got_set | got_cleared) & FNONBLOCK) != 0) {
669 tmp = fp->f_flag & FNONBLOCK;
670 error = fo_ioctl(fp, FIONBIO, &tmp, td->td_ucred, td);
671 if (error != 0)
672 goto revert_flags;
673 }
674 if (((got_set | got_cleared) & FASYNC) != 0) {
675 tmp = fp->f_flag & FASYNC;
676 error = fo_ioctl(fp, FIOASYNC, &tmp, td->td_ucred, td);
677 if (error != 0)
678 goto revert_nonblock;
679 }
680 fsetfl_unlock(fp);
681 fdrop(fp, td);
682 break;
683 revert_nonblock:
684 if (((got_set | got_cleared) & FNONBLOCK) != 0) {
685 tmp = ~fp->f_flag & FNONBLOCK;
686 (void)fo_ioctl(fp, FIONBIO, &tmp, td->td_ucred, td);
687 }
688 revert_flags:
689 do {
690 tmp = flg = fp->f_flag;
691 tmp &= ~FCNTLFLAGS;
692 tmp |= got_cleared;
693 tmp &= ~got_set;
694 } while (atomic_cmpset_int(&fp->f_flag, flg, tmp) == 0);
695 fsetfl_unlock(fp);
696 fdrop(fp, td);
697 break;
698
699 case F_GETOWN:
700 error = fget_fcntl(td, fd, &cap_fcntl_rights, F_GETOWN, &fp);
701 if (error != 0)
702 break;
703 error = fo_ioctl(fp, FIOGETOWN, &tmp, td->td_ucred, td);
704 if (error == 0)
705 td->td_retval[0] = tmp;
706 fdrop(fp, td);
707 break;
708
709 case F_SETOWN:
710 error = fget_fcntl(td, fd, &cap_fcntl_rights, F_SETOWN, &fp);
711 if (error != 0)
712 break;
713 tmp = arg;
714 error = fo_ioctl(fp, FIOSETOWN, &tmp, td->td_ucred, td);
715 fdrop(fp, td);
716 break;
717
718 case F_SETLK_REMOTE:
719 error = priv_check(td, PRIV_NFS_LOCKD);
720 if (error != 0)
721 return (error);
722 flg = F_REMOTE;
723 goto do_setlk;
724
725 case F_SETLKW:
726 flg |= F_WAIT;
727 /* FALLTHROUGH F_SETLK */
728
729 case F_SETLK:
730 do_setlk:
731 flp = (struct flock *)arg;
732 if ((flg & F_REMOTE) != 0 && flp->l_sysid == 0) {
733 error = EINVAL;
734 break;
735 }
736
737 error = fget_unlocked(td, fd, &cap_flock_rights, &fp);
738 if (error != 0)
739 break;
740 if (fp->f_type != DTYPE_VNODE || fp->f_ops == &path_fileops) {
741 error = EBADF;
742 fdrop(fp, td);
743 break;
744 }
745
746 if (flp->l_whence == SEEK_CUR) {
747 foffset = foffset_get(fp);
748 if (foffset < 0 ||
749 (flp->l_start > 0 &&
750 foffset > OFF_MAX - flp->l_start)) {
751 error = EOVERFLOW;
752 fdrop(fp, td);
753 break;
754 }
755 flp->l_start += foffset;
756 }
757
758 vp = fp->f_vnode;
759 switch (flp->l_type) {
760 case F_RDLCK:
761 if ((fp->f_flag & FREAD) == 0) {
762 error = EBADF;
763 break;
764 }
765 if ((p->p_leader->p_flag & P_ADVLOCK) == 0) {
766 PROC_LOCK(p->p_leader);
767 p->p_leader->p_flag |= P_ADVLOCK;
768 PROC_UNLOCK(p->p_leader);
769 }
770 error = VOP_ADVLOCK(vp, (caddr_t)p->p_leader, F_SETLK,
771 flp, flg);
772 break;
773 case F_WRLCK:
774 if ((fp->f_flag & FWRITE) == 0) {
775 error = EBADF;
776 break;
777 }
778 if ((p->p_leader->p_flag & P_ADVLOCK) == 0) {
779 PROC_LOCK(p->p_leader);
780 p->p_leader->p_flag |= P_ADVLOCK;
781 PROC_UNLOCK(p->p_leader);
782 }
783 error = VOP_ADVLOCK(vp, (caddr_t)p->p_leader, F_SETLK,
784 flp, flg);
785 break;
786 case F_UNLCK:
787 error = VOP_ADVLOCK(vp, (caddr_t)p->p_leader, F_UNLCK,
788 flp, flg);
789 break;
790 case F_UNLCKSYS:
791 if (flg != F_REMOTE) {
792 error = EINVAL;
793 break;
794 }
795 error = VOP_ADVLOCK(vp, (caddr_t)p->p_leader,
796 F_UNLCKSYS, flp, flg);
797 break;
798 default:
799 error = EINVAL;
800 break;
801 }
802 if (error != 0 || flp->l_type == F_UNLCK ||
803 flp->l_type == F_UNLCKSYS) {
804 fdrop(fp, td);
805 break;
806 }
807
808 /*
809 * Check for a race with close.
810 *
811 * The vnode is now advisory locked (or unlocked, but this case
812 * is not really important) as the caller requested.
813 * We had to drop the filedesc lock, so we need to recheck if
814 * the descriptor is still valid, because if it was closed
815 * in the meantime we need to remove advisory lock from the
816 * vnode - close on any descriptor leading to an advisory
817 * locked vnode, removes that lock.
818 * We will return 0 on purpose in that case, as the result of
819 * successful advisory lock might have been externally visible
820 * already. This is fine - effectively we pretend to the caller
821 * that the closing thread was a bit slower and that the
822 * advisory lock succeeded before the close.
823 */
824 error = fget_unlocked(td, fd, &cap_no_rights, &fp2);
825 if (error != 0) {
826 fdrop(fp, td);
827 break;
828 }
829 if (fp != fp2) {
830 flp->l_whence = SEEK_SET;
831 flp->l_start = 0;
832 flp->l_len = 0;
833 flp->l_type = F_UNLCK;
834 (void) VOP_ADVLOCK(vp, (caddr_t)p->p_leader,
835 F_UNLCK, flp, F_POSIX);
836 }
837 fdrop(fp, td);
838 fdrop(fp2, td);
839 break;
840
841 case F_GETLK:
842 error = fget_unlocked(td, fd, &cap_flock_rights, &fp);
843 if (error != 0)
844 break;
845 if (fp->f_type != DTYPE_VNODE || fp->f_ops == &path_fileops) {
846 error = EBADF;
847 fdrop(fp, td);
848 break;
849 }
850 flp = (struct flock *)arg;
851 if (flp->l_type != F_RDLCK && flp->l_type != F_WRLCK &&
852 flp->l_type != F_UNLCK) {
853 error = EINVAL;
854 fdrop(fp, td);
855 break;
856 }
857 if (flp->l_whence == SEEK_CUR) {
858 foffset = foffset_get(fp);
859 if ((flp->l_start > 0 &&
860 foffset > OFF_MAX - flp->l_start) ||
861 (flp->l_start < 0 &&
862 foffset < OFF_MIN - flp->l_start)) {
863 error = EOVERFLOW;
864 fdrop(fp, td);
865 break;
866 }
867 flp->l_start += foffset;
868 }
869 vp = fp->f_vnode;
870 error = VOP_ADVLOCK(vp, (caddr_t)p->p_leader, F_GETLK, flp,
871 F_POSIX);
872 fdrop(fp, td);
873 break;
874
875 case F_ADD_SEALS:
876 error = fget_unlocked(td, fd, &cap_no_rights, &fp);
877 if (error != 0)
878 break;
879 error = fo_add_seals(fp, arg);
880 fdrop(fp, td);
881 break;
882
883 case F_GET_SEALS:
884 error = fget_unlocked(td, fd, &cap_no_rights, &fp);
885 if (error != 0)
886 break;
887 if (fo_get_seals(fp, &seals) == 0)
888 td->td_retval[0] = seals;
889 else
890 error = EINVAL;
891 fdrop(fp, td);
892 break;
893
894 case F_RDAHEAD:
895 arg = arg ? 128 * 1024: 0;
896 /* FALLTHROUGH */
897 case F_READAHEAD:
898 error = fget_unlocked(td, fd, &cap_no_rights, &fp);
899 if (error != 0)
900 break;
901 if (fp->f_type != DTYPE_VNODE || fp->f_ops == &path_fileops) {
902 fdrop(fp, td);
903 error = EBADF;
904 break;
905 }
906 vp = fp->f_vnode;
907 if (vp->v_type != VREG) {
908 fdrop(fp, td);
909 error = ENOTTY;
910 break;
911 }
912
913 /*
914 * Exclusive lock synchronizes against f_seqcount reads and
915 * writes in sequential_heuristic().
916 */
917 error = vn_lock(vp, LK_EXCLUSIVE);
918 if (error != 0) {
919 fdrop(fp, td);
920 break;
921 }
922 if (arg >= 0) {
923 bsize = fp->f_vnode->v_mount->mnt_stat.f_iosize;
924 arg = MIN(arg, INT_MAX - bsize + 1);
925 fp->f_seqcount[UIO_READ] = MIN(IO_SEQMAX,
926 (arg + bsize - 1) / bsize);
927 atomic_set_int(&fp->f_flag, FRDAHEAD);
928 } else {
929 atomic_clear_int(&fp->f_flag, FRDAHEAD);
930 }
931 VOP_UNLOCK(vp);
932 fdrop(fp, td);
933 break;
934
935 case F_ISUNIONSTACK:
936 /*
937 * Check if the vnode is part of a union stack (either the
938 * "union" flag from mount(2) or unionfs).
939 *
940 * Prior to introduction of this op libc's readdir would call
941 * fstatfs(2), in effect unnecessarily copying kilobytes of
942 * data just to check fs name and a mount flag.
943 *
944 * Fixing the code to handle everything in the kernel instead
945 * is a non-trivial endeavor and has low priority, thus this
946 * horrible kludge facilitates the current behavior in a much
947 * cheaper manner until someone(tm) sorts this out.
948 */
949 error = fget_unlocked(td, fd, &cap_no_rights, &fp);
950 if (error != 0)
951 break;
952 if (fp->f_type != DTYPE_VNODE) {
953 fdrop(fp, td);
954 error = EBADF;
955 break;
956 }
957 vp = fp->f_vnode;
958 /*
959 * Since we don't prevent dooming the vnode even non-null mp
960 * found can become immediately stale. This is tolerable since
961 * mount points are type-stable (providing safe memory access)
962 * and any vfs op on this vnode going forward will return an
963 * error (meaning return value in this case is meaningless).
964 */
965 mp = atomic_load_ptr(&vp->v_mount);
966 if (__predict_false(mp == NULL)) {
967 fdrop(fp, td);
968 error = EBADF;
969 break;
970 }
971 td->td_retval[0] = 0;
972 if (mp->mnt_kern_flag & MNTK_UNIONFS ||
973 mp->mnt_flag & MNT_UNION)
974 td->td_retval[0] = 1;
975 fdrop(fp, td);
976 break;
977
978 case F_KINFO:
979 #ifdef CAPABILITY_MODE
980 if (CAP_TRACING(td))
981 ktrcapfail(CAPFAIL_SYSCALL, &cmd);
982 if (IN_CAPABILITY_MODE(td)) {
983 error = ECAPMODE;
984 break;
985 }
986 #endif
987 error = copyin((void *)arg, &kif_sz, sizeof(kif_sz));
988 if (error != 0)
989 break;
990 if (kif_sz != sizeof(*kif)) {
991 error = EINVAL;
992 break;
993 }
994 kif = malloc(sizeof(*kif), M_TEMP, M_WAITOK | M_ZERO);
995 FILEDESC_SLOCK(fdp);
996 error = fget_cap_noref(fdp, fd, &cap_fcntl_rights, &fp, NULL);
997 if (error == 0 && fhold(fp)) {
998 export_file_to_kinfo(fp, fd, NULL, kif, fdp, 0);
999 FILEDESC_SUNLOCK(fdp);
1000 fdrop(fp, td);
1001 if ((kif->kf_status & KF_ATTR_VALID) != 0) {
1002 kif->kf_structsize = sizeof(*kif);
1003 error = copyout(kif, (void *)arg, sizeof(*kif));
1004 } else {
1005 error = EBADF;
1006 }
1007 } else {
1008 FILEDESC_SUNLOCK(fdp);
1009 if (error == 0)
1010 error = EBADF;
1011 }
1012 free(kif, M_TEMP);
1013 break;
1014
1015 default:
1016 if ((cmd & ((1u << F_DUP3FD_SHIFT) - 1)) != F_DUP3FD)
1017 return (EXTERROR(EINVAL, "invalid fcntl cmd"));
1018 /* Handle F_DUP3FD */
1019 flags = (cmd >> F_DUP3FD_SHIFT);
1020 if ((flags & ~(FD_CLOEXEC | FD_CLOFORK)) != 0)
1021 return (EXTERROR(EINVAL, "invalid flags for F_DUP3FD"));
1022 tmp = arg;
1023 error = kern_dup(td, FDDUP_FIXED,
1024 ((flags & FD_CLOEXEC) != 0 ? FDDUP_FLAG_CLOEXEC : 0) |
1025 ((flags & FD_CLOFORK) != 0 ? FDDUP_FLAG_CLOFORK : 0),
1026 fd, tmp);
1027 break;
1028 }
1029 return (error);
1030 }
1031
1032 static int
getmaxfd(struct thread * td)1033 getmaxfd(struct thread *td)
1034 {
1035
1036 return (min((int)lim_cur(td, RLIMIT_NOFILE), maxfilesperproc));
1037 }
1038
1039 /*
1040 * Common code for dup, dup2, fcntl(F_DUPFD) and fcntl(F_DUP2FD).
1041 */
1042 int
kern_dup(struct thread * td,u_int mode,int flags,int old,int new)1043 kern_dup(struct thread *td, u_int mode, int flags, int old, int new)
1044 {
1045 struct filedesc *fdp;
1046 struct filedescent *oldfde, *newfde;
1047 struct proc *p;
1048 struct file *delfp, *oldfp;
1049 u_long *oioctls, *nioctls;
1050 int error, maxfd;
1051
1052 p = td->td_proc;
1053 fdp = p->p_fd;
1054 oioctls = NULL;
1055
1056 MPASS((flags & ~(FDDUP_FLAG_CLOEXEC | FDDUP_FLAG_CLOFORK)) == 0);
1057 MPASS(mode < FDDUP_LASTMODE);
1058
1059 AUDIT_ARG_FD(old);
1060 /* XXXRW: if (flags & FDDUP_FIXED) AUDIT_ARG_FD2(new); */
1061
1062 /*
1063 * Verify we have a valid descriptor to dup from and possibly to
1064 * dup to. Unlike dup() and dup2(), fcntl()'s F_DUPFD should
1065 * return EINVAL when the new descriptor is out of bounds.
1066 */
1067 if (old < 0)
1068 return (EBADF);
1069 if (new < 0)
1070 return (mode == FDDUP_FCNTL ? EINVAL : EBADF);
1071 maxfd = getmaxfd(td);
1072 if (new >= maxfd)
1073 return (mode == FDDUP_FCNTL ? EINVAL : EBADF);
1074
1075 error = EBADF;
1076 FILEDESC_XLOCK(fdp);
1077 if (fget_noref(fdp, old) == NULL)
1078 goto unlock;
1079 if (mode == FDDUP_FIXED && old == new) {
1080 td->td_retval[0] = new;
1081 fdp->fd_ofiles[new].fde_flags |= fddup_to_fde_flags(flags);
1082 error = 0;
1083 goto unlock;
1084 }
1085
1086 oldfde = &fdp->fd_ofiles[old];
1087 oldfp = oldfde->fde_file;
1088 if (!fhold(oldfp))
1089 goto unlock;
1090
1091 /*
1092 * If the caller specified a file descriptor, make sure the file
1093 * table is large enough to hold it, and grab it. Otherwise, just
1094 * allocate a new descriptor the usual way.
1095 */
1096 switch (mode) {
1097 case FDDUP_NORMAL:
1098 case FDDUP_FCNTL:
1099 if ((error = fdalloc(td, new, &new)) != 0) {
1100 fdrop(oldfp, td);
1101 goto unlock;
1102 }
1103 break;
1104 case FDDUP_FIXED:
1105 if (new >= fdp->fd_nfiles) {
1106 /*
1107 * The resource limits are here instead of e.g.
1108 * fdalloc(), because the file descriptor table may be
1109 * shared between processes, so we can't really use
1110 * racct_add()/racct_sub(). Instead of counting the
1111 * number of actually allocated descriptors, just put
1112 * the limit on the size of the file descriptor table.
1113 */
1114 #ifdef RACCT
1115 if (RACCT_ENABLED()) {
1116 error = racct_set_unlocked(p, RACCT_NOFILE, new + 1);
1117 if (error != 0) {
1118 error = EMFILE;
1119 fdrop(oldfp, td);
1120 goto unlock;
1121 }
1122 }
1123 #endif
1124 fdgrowtable_exp(fdp, new + 1);
1125 }
1126 if (!fdisused(fdp, new))
1127 fdused(fdp, new);
1128 break;
1129 default:
1130 KASSERT(0, ("%s unsupported mode %d", __func__, mode));
1131 }
1132
1133 KASSERT(old != new, ("new fd is same as old"));
1134
1135 /* Refetch oldfde because the table may have grown and old one freed. */
1136 oldfde = &fdp->fd_ofiles[old];
1137 KASSERT(oldfp == oldfde->fde_file,
1138 ("fdt_ofiles shift from growth observed at fd %d",
1139 old));
1140
1141 newfde = &fdp->fd_ofiles[new];
1142 delfp = newfde->fde_file;
1143
1144 nioctls = filecaps_copy_prep(&oldfde->fde_caps);
1145
1146 /*
1147 * Duplicate the source descriptor.
1148 */
1149 #ifdef CAPABILITIES
1150 seqc_write_begin(&newfde->fde_seqc);
1151 #endif
1152 oioctls = filecaps_free_prep(&newfde->fde_caps);
1153 fde_copy(oldfde, newfde);
1154 filecaps_copy_finish(&oldfde->fde_caps, &newfde->fde_caps,
1155 nioctls);
1156 newfde->fde_flags = (oldfde->fde_flags & ~(UF_EXCLOSE | UF_FOCLOSE)) |
1157 fddup_to_fde_flags(flags);
1158 #ifdef CAPABILITIES
1159 seqc_write_end(&newfde->fde_seqc);
1160 #endif
1161 td->td_retval[0] = new;
1162
1163 error = 0;
1164
1165 if (delfp != NULL) {
1166 (void) closefp(fdp, new, delfp, td, true, false);
1167 FILEDESC_UNLOCK_ASSERT(fdp);
1168 } else {
1169 unlock:
1170 FILEDESC_XUNLOCK(fdp);
1171 }
1172
1173 filecaps_free_finish(oioctls);
1174 return (error);
1175 }
1176
1177 static void
sigiofree(struct sigio * sigio)1178 sigiofree(struct sigio *sigio)
1179 {
1180 crfree(sigio->sio_ucred);
1181 free(sigio, M_SIGIO);
1182 }
1183
1184 static struct sigio *
funsetown_locked(struct sigio * sigio)1185 funsetown_locked(struct sigio *sigio)
1186 {
1187 struct proc *p;
1188 struct pgrp *pg;
1189
1190 SIGIO_ASSERT_LOCKED();
1191
1192 if (sigio == NULL)
1193 return (NULL);
1194 *sigio->sio_myref = NULL;
1195 if (sigio->sio_pgid < 0) {
1196 pg = sigio->sio_pgrp;
1197 PGRP_LOCK(pg);
1198 SLIST_REMOVE(&pg->pg_sigiolst, sigio, sigio, sio_pgsigio);
1199 PGRP_UNLOCK(pg);
1200 } else {
1201 p = sigio->sio_proc;
1202 PROC_LOCK(p);
1203 SLIST_REMOVE(&p->p_sigiolst, sigio, sigio, sio_pgsigio);
1204 PROC_UNLOCK(p);
1205 }
1206 return (sigio);
1207 }
1208
1209 /*
1210 * If sigio is on the list associated with a process or process group,
1211 * disable signalling from the device, remove sigio from the list and
1212 * free sigio.
1213 */
1214 void
funsetown(struct sigio ** sigiop)1215 funsetown(struct sigio **sigiop)
1216 {
1217 struct sigio *sigio;
1218
1219 /* Racy check, consumers must provide synchronization. */
1220 if (*sigiop == NULL)
1221 return;
1222
1223 SIGIO_LOCK();
1224 sigio = funsetown_locked(*sigiop);
1225 SIGIO_UNLOCK();
1226 if (sigio != NULL)
1227 sigiofree(sigio);
1228 }
1229
1230 /*
1231 * Free a list of sigio structures. The caller must ensure that new sigio
1232 * structures cannot be added after this point. For process groups this is
1233 * guaranteed using the proctree lock; for processes, the P_WEXIT flag serves
1234 * as an interlock.
1235 */
1236 void
funsetownlst(struct sigiolst * sigiolst)1237 funsetownlst(struct sigiolst *sigiolst)
1238 {
1239 struct proc *p;
1240 struct pgrp *pg;
1241 struct sigio *sigio, *tmp;
1242
1243 /* Racy check. */
1244 sigio = SLIST_FIRST(sigiolst);
1245 if (sigio == NULL)
1246 return;
1247
1248 p = NULL;
1249 pg = NULL;
1250
1251 SIGIO_LOCK();
1252 sigio = SLIST_FIRST(sigiolst);
1253 if (sigio == NULL) {
1254 SIGIO_UNLOCK();
1255 return;
1256 }
1257
1258 /*
1259 * Every entry of the list should belong to a single proc or pgrp.
1260 */
1261 if (sigio->sio_pgid < 0) {
1262 pg = sigio->sio_pgrp;
1263 sx_assert(&proctree_lock, SX_XLOCKED);
1264 PGRP_LOCK(pg);
1265 } else /* if (sigio->sio_pgid > 0) */ {
1266 p = sigio->sio_proc;
1267 PROC_LOCK(p);
1268 KASSERT((p->p_flag & P_WEXIT) != 0,
1269 ("%s: process %p is not exiting", __func__, p));
1270 }
1271
1272 SLIST_FOREACH(sigio, sigiolst, sio_pgsigio) {
1273 *sigio->sio_myref = NULL;
1274 if (pg != NULL) {
1275 KASSERT(sigio->sio_pgid < 0,
1276 ("Proc sigio in pgrp sigio list"));
1277 KASSERT(sigio->sio_pgrp == pg,
1278 ("Bogus pgrp in sigio list"));
1279 } else /* if (p != NULL) */ {
1280 KASSERT(sigio->sio_pgid > 0,
1281 ("Pgrp sigio in proc sigio list"));
1282 KASSERT(sigio->sio_proc == p,
1283 ("Bogus proc in sigio list"));
1284 }
1285 }
1286
1287 if (pg != NULL)
1288 PGRP_UNLOCK(pg);
1289 else
1290 PROC_UNLOCK(p);
1291 SIGIO_UNLOCK();
1292
1293 SLIST_FOREACH_SAFE(sigio, sigiolst, sio_pgsigio, tmp)
1294 sigiofree(sigio);
1295 }
1296
1297 /*
1298 * This is common code for FIOSETOWN ioctl called by fcntl(fd, F_SETOWN, arg).
1299 *
1300 * After permission checking, add a sigio structure to the sigio list for
1301 * the process or process group.
1302 */
1303 int
fsetown(pid_t pgid,struct sigio ** sigiop)1304 fsetown(pid_t pgid, struct sigio **sigiop)
1305 {
1306 struct proc *proc;
1307 struct pgrp *pgrp;
1308 struct sigio *osigio, *sigio;
1309 int ret;
1310
1311 if (pgid == 0) {
1312 funsetown(sigiop);
1313 return (0);
1314 }
1315
1316 sigio = malloc(sizeof(struct sigio), M_SIGIO, M_WAITOK);
1317 sigio->sio_pgid = pgid;
1318 sigio->sio_ucred = crhold(curthread->td_ucred);
1319 sigio->sio_myref = sigiop;
1320
1321 ret = 0;
1322 if (pgid > 0) {
1323 ret = pget(pgid, PGET_NOTWEXIT | PGET_NOTID | PGET_HOLD, &proc);
1324 SIGIO_LOCK();
1325 osigio = funsetown_locked(*sigiop);
1326 if (ret == 0) {
1327 PROC_LOCK(proc);
1328 _PRELE(proc);
1329 if ((proc->p_flag & P_WEXIT) != 0) {
1330 ret = ESRCH;
1331 } else if (proc->p_session !=
1332 curthread->td_proc->p_session) {
1333 /*
1334 * Policy - Don't allow a process to FSETOWN a
1335 * process in another session.
1336 *
1337 * Remove this test to allow maximum flexibility
1338 * or restrict FSETOWN to the current process or
1339 * process group for maximum safety.
1340 */
1341 ret = EPERM;
1342 } else {
1343 sigio->sio_proc = proc;
1344 SLIST_INSERT_HEAD(&proc->p_sigiolst, sigio,
1345 sio_pgsigio);
1346 }
1347 PROC_UNLOCK(proc);
1348 }
1349 } else /* if (pgid < 0) */ {
1350 sx_slock(&proctree_lock);
1351 SIGIO_LOCK();
1352 osigio = funsetown_locked(*sigiop);
1353 pgrp = pgfind(-pgid);
1354 if (pgrp == NULL) {
1355 ret = ESRCH;
1356 } else {
1357 if (pgrp->pg_session != curthread->td_proc->p_session) {
1358 /*
1359 * Policy - Don't allow a process to FSETOWN a
1360 * process in another session.
1361 *
1362 * Remove this test to allow maximum flexibility
1363 * or restrict FSETOWN to the current process or
1364 * process group for maximum safety.
1365 */
1366 ret = EPERM;
1367 } else {
1368 sigio->sio_pgrp = pgrp;
1369 SLIST_INSERT_HEAD(&pgrp->pg_sigiolst, sigio,
1370 sio_pgsigio);
1371 }
1372 PGRP_UNLOCK(pgrp);
1373 }
1374 sx_sunlock(&proctree_lock);
1375 }
1376 if (ret == 0)
1377 *sigiop = sigio;
1378 SIGIO_UNLOCK();
1379 if (osigio != NULL)
1380 sigiofree(osigio);
1381 return (ret);
1382 }
1383
1384 /*
1385 * This is common code for FIOGETOWN ioctl called by fcntl(fd, F_GETOWN, arg).
1386 */
1387 pid_t
fgetown(struct sigio ** sigiop)1388 fgetown(struct sigio **sigiop)
1389 {
1390 pid_t pgid;
1391
1392 SIGIO_LOCK();
1393 pgid = (*sigiop != NULL) ? (*sigiop)->sio_pgid : 0;
1394 SIGIO_UNLOCK();
1395 return (pgid);
1396 }
1397
1398 static int
closefp_impl(struct filedesc * fdp,int fd,struct file * fp,struct thread * td,bool audit)1399 closefp_impl(struct filedesc *fdp, int fd, struct file *fp, struct thread *td,
1400 bool audit)
1401 {
1402 int error;
1403
1404 FILEDESC_XLOCK_ASSERT(fdp);
1405
1406 /*
1407 * We now hold the fp reference that used to be owned by the
1408 * descriptor array. We have to unlock the FILEDESC *AFTER*
1409 * knote_fdclose to prevent a race of the fd getting opened, a knote
1410 * added, and deleteing a knote for the new fd.
1411 */
1412 if (__predict_false(!TAILQ_EMPTY(&fdp->fd_kqlist)))
1413 knote_fdclose(td, fd);
1414
1415 if (fp->f_ops->fo_fdclose != NULL)
1416 fp->f_ops->fo_fdclose(fp, fd, td);
1417 FILEDESC_XUNLOCK(fdp);
1418
1419 #ifdef AUDIT
1420 if (AUDITING_TD(td) && audit)
1421 audit_sysclose(td, fd, fp);
1422 #endif
1423 error = closef(fp, td);
1424
1425 /*
1426 * All paths leading up to closefp() will have already removed or
1427 * replaced the fd in the filedesc table, so a restart would not
1428 * operate on the same file.
1429 */
1430 if (error == ERESTART)
1431 error = EINTR;
1432
1433 return (error);
1434 }
1435
1436 static int
closefp_hl(struct filedesc * fdp,int fd,struct file * fp,struct thread * td,bool holdleaders,bool audit)1437 closefp_hl(struct filedesc *fdp, int fd, struct file *fp, struct thread *td,
1438 bool holdleaders, bool audit)
1439 {
1440 int error;
1441
1442 FILEDESC_XLOCK_ASSERT(fdp);
1443
1444 if (holdleaders) {
1445 if (td->td_proc->p_fdtol != NULL) {
1446 /*
1447 * Ask fdfree() to sleep to ensure that all relevant
1448 * process leaders can be traversed in closef().
1449 */
1450 fdp->fd_holdleaderscount++;
1451 } else {
1452 holdleaders = false;
1453 }
1454 }
1455
1456 error = closefp_impl(fdp, fd, fp, td, audit);
1457 if (holdleaders) {
1458 FILEDESC_XLOCK(fdp);
1459 fdp->fd_holdleaderscount--;
1460 if (fdp->fd_holdleaderscount == 0 &&
1461 fdp->fd_holdleaderswakeup != 0) {
1462 fdp->fd_holdleaderswakeup = 0;
1463 wakeup(&fdp->fd_holdleaderscount);
1464 }
1465 FILEDESC_XUNLOCK(fdp);
1466 }
1467 return (error);
1468 }
1469
1470 static int
closefp(struct filedesc * fdp,int fd,struct file * fp,struct thread * td,bool holdleaders,bool audit)1471 closefp(struct filedesc *fdp, int fd, struct file *fp, struct thread *td,
1472 bool holdleaders, bool audit)
1473 {
1474
1475 FILEDESC_XLOCK_ASSERT(fdp);
1476
1477 if (__predict_false(td->td_proc->p_fdtol != NULL)) {
1478 return (closefp_hl(fdp, fd, fp, td, holdleaders, audit));
1479 } else {
1480 return (closefp_impl(fdp, fd, fp, td, audit));
1481 }
1482 }
1483
1484 /*
1485 * Close a file descriptor.
1486 */
1487 #ifndef _SYS_SYSPROTO_H_
1488 struct close_args {
1489 int fd;
1490 };
1491 #endif
1492 /* ARGSUSED */
1493 int
sys_close(struct thread * td,struct close_args * uap)1494 sys_close(struct thread *td, struct close_args *uap)
1495 {
1496
1497 return (kern_close(td, uap->fd));
1498 }
1499
1500 int
kern_close(struct thread * td,int fd)1501 kern_close(struct thread *td, int fd)
1502 {
1503 struct filedesc *fdp;
1504 struct file *fp;
1505
1506 fdp = td->td_proc->p_fd;
1507
1508 FILEDESC_XLOCK(fdp);
1509 if ((fp = fget_noref(fdp, fd)) == NULL) {
1510 FILEDESC_XUNLOCK(fdp);
1511 return (EBADF);
1512 }
1513 fdfree(fdp, fd);
1514
1515 /* closefp() drops the FILEDESC lock for us. */
1516 return (closefp(fdp, fd, fp, td, true, true));
1517 }
1518
1519 static int
close_range_flags(struct thread * td,u_int lowfd,u_int highfd,int flags)1520 close_range_flags(struct thread *td, u_int lowfd, u_int highfd, int flags)
1521 {
1522 struct filedesc *fdp;
1523 struct fdescenttbl *fdt;
1524 struct filedescent *fde;
1525 int fd, fde_flags;
1526
1527 fde_flags = close_range_to_fde_flags(flags);
1528 fdp = td->td_proc->p_fd;
1529 FILEDESC_XLOCK(fdp);
1530 fdt = atomic_load_ptr(&fdp->fd_files);
1531 highfd = MIN(highfd, fdt->fdt_nfiles - 1);
1532 fd = lowfd;
1533 if (__predict_false(fd > highfd)) {
1534 goto out_locked;
1535 }
1536 for (; fd <= highfd; fd++) {
1537 fde = &fdt->fdt_ofiles[fd];
1538 if (fde->fde_file != NULL)
1539 fde->fde_flags |= fde_flags;
1540 }
1541 out_locked:
1542 FILEDESC_XUNLOCK(fdp);
1543 return (0);
1544 }
1545
1546 static int
close_range_impl(struct thread * td,u_int lowfd,u_int highfd)1547 close_range_impl(struct thread *td, u_int lowfd, u_int highfd)
1548 {
1549 struct filedesc *fdp;
1550 const struct fdescenttbl *fdt;
1551 struct file *fp;
1552 int fd;
1553
1554 fdp = td->td_proc->p_fd;
1555 FILEDESC_XLOCK(fdp);
1556 fdt = atomic_load_ptr(&fdp->fd_files);
1557 highfd = MIN(highfd, fdt->fdt_nfiles - 1);
1558 fd = lowfd;
1559 if (__predict_false(fd > highfd)) {
1560 goto out_locked;
1561 }
1562 for (;;) {
1563 fp = fdt->fdt_ofiles[fd].fde_file;
1564 if (fp == NULL) {
1565 if (fd == highfd)
1566 goto out_locked;
1567 } else {
1568 fdfree(fdp, fd);
1569 (void) closefp(fdp, fd, fp, td, true, true);
1570 if (fd == highfd)
1571 goto out_unlocked;
1572 FILEDESC_XLOCK(fdp);
1573 fdt = atomic_load_ptr(&fdp->fd_files);
1574 }
1575 fd++;
1576 }
1577 out_locked:
1578 FILEDESC_XUNLOCK(fdp);
1579 out_unlocked:
1580 return (0);
1581 }
1582
1583 int
kern_close_range(struct thread * td,int flags,u_int lowfd,u_int highfd)1584 kern_close_range(struct thread *td, int flags, u_int lowfd, u_int highfd)
1585 {
1586
1587 /*
1588 * Check this prior to clamping; closefrom(3) with only fd 0, 1, and 2
1589 * open should not be a usage error. From a close_range() perspective,
1590 * close_range(3, ~0U, 0) in the same scenario should also likely not
1591 * be a usage error as all fd above 3 are in-fact already closed.
1592 */
1593 if (highfd < lowfd) {
1594 return (EINVAL);
1595 }
1596
1597 if ((flags & (CLOSE_RANGE_CLOEXEC | CLOSE_RANGE_CLOFORK)) != 0)
1598 return (close_range_flags(td, lowfd, highfd, flags));
1599
1600 return (close_range_impl(td, lowfd, highfd));
1601 }
1602
1603 #ifndef _SYS_SYSPROTO_H_
1604 struct close_range_args {
1605 u_int lowfd;
1606 u_int highfd;
1607 int flags;
1608 };
1609 #endif
1610 int
sys_close_range(struct thread * td,struct close_range_args * uap)1611 sys_close_range(struct thread *td, struct close_range_args *uap)
1612 {
1613
1614 AUDIT_ARG_FD(uap->lowfd);
1615 AUDIT_ARG_CMD(uap->highfd);
1616 AUDIT_ARG_FFLAGS(uap->flags);
1617
1618 if ((uap->flags & ~(CLOSE_RANGE_CLOEXEC | CLOSE_RANGE_CLOFORK)) != 0)
1619 return (EINVAL);
1620 return (kern_close_range(td, uap->flags, uap->lowfd, uap->highfd));
1621 }
1622
1623 #ifdef COMPAT_FREEBSD12
1624 /*
1625 * Close open file descriptors.
1626 */
1627 #ifndef _SYS_SYSPROTO_H_
1628 struct freebsd12_closefrom_args {
1629 int lowfd;
1630 };
1631 #endif
1632 /* ARGSUSED */
1633 int
freebsd12_closefrom(struct thread * td,struct freebsd12_closefrom_args * uap)1634 freebsd12_closefrom(struct thread *td, struct freebsd12_closefrom_args *uap)
1635 {
1636 u_int lowfd;
1637
1638 AUDIT_ARG_FD(uap->lowfd);
1639
1640 /*
1641 * Treat negative starting file descriptor values identical to
1642 * closefrom(0) which closes all files.
1643 */
1644 lowfd = MAX(0, uap->lowfd);
1645 return (kern_close_range(td, 0, lowfd, ~0U));
1646 }
1647 #endif /* COMPAT_FREEBSD12 */
1648
1649 #if defined(COMPAT_43)
1650 /*
1651 * Return status information about a file descriptor.
1652 */
1653 #ifndef _SYS_SYSPROTO_H_
1654 struct ofstat_args {
1655 int fd;
1656 struct ostat *sb;
1657 };
1658 #endif
1659 /* ARGSUSED */
1660 int
ofstat(struct thread * td,struct ofstat_args * uap)1661 ofstat(struct thread *td, struct ofstat_args *uap)
1662 {
1663 struct ostat oub;
1664 struct stat ub;
1665 int error;
1666
1667 error = kern_fstat(td, uap->fd, &ub);
1668 if (error == 0) {
1669 cvtstat(&ub, &oub);
1670 error = copyout(&oub, uap->sb, sizeof(oub));
1671 }
1672 return (error);
1673 }
1674 #endif /* COMPAT_43 */
1675
1676 #if defined(COMPAT_FREEBSD11)
1677 int
freebsd11_fstat(struct thread * td,struct freebsd11_fstat_args * uap)1678 freebsd11_fstat(struct thread *td, struct freebsd11_fstat_args *uap)
1679 {
1680 struct stat sb;
1681 struct freebsd11_stat osb;
1682 int error;
1683
1684 error = kern_fstat(td, uap->fd, &sb);
1685 if (error != 0)
1686 return (error);
1687 error = freebsd11_cvtstat(&sb, &osb);
1688 if (error == 0)
1689 error = copyout(&osb, uap->sb, sizeof(osb));
1690 return (error);
1691 }
1692 #endif /* COMPAT_FREEBSD11 */
1693
1694 /*
1695 * Return status information about a file descriptor.
1696 */
1697 #ifndef _SYS_SYSPROTO_H_
1698 struct fstat_args {
1699 int fd;
1700 struct stat *sb;
1701 };
1702 #endif
1703 /* ARGSUSED */
1704 int
sys_fstat(struct thread * td,struct fstat_args * uap)1705 sys_fstat(struct thread *td, struct fstat_args *uap)
1706 {
1707 struct stat ub;
1708 int error;
1709
1710 error = kern_fstat(td, uap->fd, &ub);
1711 if (error == 0)
1712 error = copyout(&ub, uap->sb, sizeof(ub));
1713 return (error);
1714 }
1715
1716 int
kern_fstat(struct thread * td,int fd,struct stat * sbp)1717 kern_fstat(struct thread *td, int fd, struct stat *sbp)
1718 {
1719 struct file *fp;
1720 int error;
1721
1722 AUDIT_ARG_FD(fd);
1723
1724 error = fget(td, fd, &cap_fstat_rights, &fp);
1725 if (__predict_false(error != 0))
1726 return (error);
1727
1728 AUDIT_ARG_FILE(td->td_proc, fp);
1729
1730 sbp->st_filerev = 0;
1731 sbp->st_bsdflags = 0;
1732 error = fo_stat(fp, sbp, td->td_ucred);
1733 fdrop(fp, td);
1734 #ifdef __STAT_TIME_T_EXT
1735 sbp->st_atim_ext = 0;
1736 sbp->st_mtim_ext = 0;
1737 sbp->st_ctim_ext = 0;
1738 sbp->st_btim_ext = 0;
1739 #endif
1740 #ifdef KTRACE
1741 if (KTRPOINT(td, KTR_STRUCT))
1742 ktrstat_error(sbp, error);
1743 #endif
1744 return (error);
1745 }
1746
1747 #if defined(COMPAT_FREEBSD11)
1748 /*
1749 * Return status information about a file descriptor.
1750 */
1751 #ifndef _SYS_SYSPROTO_H_
1752 struct freebsd11_nfstat_args {
1753 int fd;
1754 struct nstat *sb;
1755 };
1756 #endif
1757 /* ARGSUSED */
1758 int
freebsd11_nfstat(struct thread * td,struct freebsd11_nfstat_args * uap)1759 freebsd11_nfstat(struct thread *td, struct freebsd11_nfstat_args *uap)
1760 {
1761 struct nstat nub;
1762 struct stat ub;
1763 int error;
1764
1765 error = kern_fstat(td, uap->fd, &ub);
1766 if (error != 0)
1767 return (error);
1768 error = freebsd11_cvtnstat(&ub, &nub);
1769 if (error != 0)
1770 error = copyout(&nub, uap->sb, sizeof(nub));
1771 return (error);
1772 }
1773 #endif /* COMPAT_FREEBSD11 */
1774
1775 /*
1776 * Return pathconf information about a file descriptor.
1777 */
1778 #ifndef _SYS_SYSPROTO_H_
1779 struct fpathconf_args {
1780 int fd;
1781 int name;
1782 };
1783 #endif
1784 /* ARGSUSED */
1785 int
sys_fpathconf(struct thread * td,struct fpathconf_args * uap)1786 sys_fpathconf(struct thread *td, struct fpathconf_args *uap)
1787 {
1788 long value;
1789 int error;
1790
1791 error = kern_fpathconf(td, uap->fd, uap->name, &value);
1792 if (error == 0)
1793 td->td_retval[0] = value;
1794 return (error);
1795 }
1796
1797 int
kern_fpathconf(struct thread * td,int fd,int name,long * valuep)1798 kern_fpathconf(struct thread *td, int fd, int name, long *valuep)
1799 {
1800 struct file *fp;
1801 struct vnode *vp;
1802 int error;
1803
1804 error = fget(td, fd, &cap_fpathconf_rights, &fp);
1805 if (error != 0)
1806 return (error);
1807
1808 if (name == _PC_ASYNC_IO) {
1809 *valuep = _POSIX_ASYNCHRONOUS_IO;
1810 goto out;
1811 }
1812 vp = fp->f_vnode;
1813 if (vp != NULL) {
1814 vn_lock(vp, LK_SHARED | LK_RETRY);
1815 error = VOP_PATHCONF(vp, name, valuep);
1816 VOP_UNLOCK(vp);
1817 } else if (fp->f_type == DTYPE_PIPE || fp->f_type == DTYPE_SOCKET) {
1818 if (name != _PC_PIPE_BUF) {
1819 error = EINVAL;
1820 } else {
1821 *valuep = PIPE_BUF;
1822 error = 0;
1823 }
1824 } else {
1825 error = EOPNOTSUPP;
1826 }
1827 out:
1828 fdrop(fp, td);
1829 return (error);
1830 }
1831
1832 /*
1833 * Copy filecaps structure allocating memory for ioctls array if needed.
1834 *
1835 * The last parameter indicates whether the fdtable is locked. If it is not and
1836 * ioctls are encountered, copying fails and the caller must lock the table.
1837 *
1838 * Note that if the table was not locked, the caller has to check the relevant
1839 * sequence counter to determine whether the operation was successful.
1840 */
1841 bool
filecaps_copy(const struct filecaps * src,struct filecaps * dst,bool locked)1842 filecaps_copy(const struct filecaps *src, struct filecaps *dst, bool locked)
1843 {
1844 size_t size;
1845
1846 if (src->fc_ioctls != NULL && !locked)
1847 return (false);
1848 memcpy(dst, src, sizeof(*src));
1849 if (src->fc_ioctls == NULL)
1850 return (true);
1851
1852 KASSERT(src->fc_nioctls > 0,
1853 ("fc_ioctls != NULL, but fc_nioctls=%hd", src->fc_nioctls));
1854
1855 size = sizeof(src->fc_ioctls[0]) * src->fc_nioctls;
1856 dst->fc_ioctls = malloc(size, M_FILECAPS, M_WAITOK);
1857 memcpy(dst->fc_ioctls, src->fc_ioctls, size);
1858 return (true);
1859 }
1860
1861 static u_long *
filecaps_copy_prep(const struct filecaps * src)1862 filecaps_copy_prep(const struct filecaps *src)
1863 {
1864 u_long *ioctls;
1865 size_t size;
1866
1867 if (__predict_true(src->fc_ioctls == NULL))
1868 return (NULL);
1869
1870 KASSERT(src->fc_nioctls > 0,
1871 ("fc_ioctls != NULL, but fc_nioctls=%hd", src->fc_nioctls));
1872
1873 size = sizeof(src->fc_ioctls[0]) * src->fc_nioctls;
1874 ioctls = malloc(size, M_FILECAPS, M_WAITOK);
1875 return (ioctls);
1876 }
1877
1878 static void
filecaps_copy_finish(const struct filecaps * src,struct filecaps * dst,u_long * ioctls)1879 filecaps_copy_finish(const struct filecaps *src, struct filecaps *dst,
1880 u_long *ioctls)
1881 {
1882 size_t size;
1883
1884 *dst = *src;
1885 if (__predict_true(src->fc_ioctls == NULL)) {
1886 MPASS(ioctls == NULL);
1887 return;
1888 }
1889
1890 size = sizeof(src->fc_ioctls[0]) * src->fc_nioctls;
1891 dst->fc_ioctls = ioctls;
1892 bcopy(src->fc_ioctls, dst->fc_ioctls, size);
1893 }
1894
1895 /*
1896 * Move filecaps structure to the new place and clear the old place.
1897 */
1898 void
filecaps_move(struct filecaps * src,struct filecaps * dst)1899 filecaps_move(struct filecaps *src, struct filecaps *dst)
1900 {
1901
1902 *dst = *src;
1903 bzero(src, sizeof(*src));
1904 }
1905
1906 /*
1907 * Fill the given filecaps structure with full rights.
1908 */
1909 static void
filecaps_fill(struct filecaps * fcaps)1910 filecaps_fill(struct filecaps *fcaps)
1911 {
1912
1913 CAP_ALL(&fcaps->fc_rights);
1914 fcaps->fc_ioctls = NULL;
1915 fcaps->fc_nioctls = -1;
1916 fcaps->fc_fcntls = CAP_FCNTL_ALL;
1917 }
1918
1919 /*
1920 * Free memory allocated within filecaps structure.
1921 */
1922 static void
filecaps_free_ioctl(struct filecaps * fcaps)1923 filecaps_free_ioctl(struct filecaps *fcaps)
1924 {
1925
1926 free(fcaps->fc_ioctls, M_FILECAPS);
1927 fcaps->fc_ioctls = NULL;
1928 }
1929
1930 void
filecaps_free(struct filecaps * fcaps)1931 filecaps_free(struct filecaps *fcaps)
1932 {
1933
1934 filecaps_free_ioctl(fcaps);
1935 bzero(fcaps, sizeof(*fcaps));
1936 }
1937
1938 static u_long *
filecaps_free_prep(struct filecaps * fcaps)1939 filecaps_free_prep(struct filecaps *fcaps)
1940 {
1941 u_long *ioctls;
1942
1943 ioctls = fcaps->fc_ioctls;
1944 bzero(fcaps, sizeof(*fcaps));
1945 return (ioctls);
1946 }
1947
1948 static void
filecaps_free_finish(u_long * ioctls)1949 filecaps_free_finish(u_long *ioctls)
1950 {
1951
1952 free(ioctls, M_FILECAPS);
1953 }
1954
1955 /*
1956 * Validate the given filecaps structure.
1957 */
1958 static void
filecaps_validate(const struct filecaps * fcaps,const char * func)1959 filecaps_validate(const struct filecaps *fcaps, const char *func)
1960 {
1961
1962 KASSERT(cap_rights_is_valid(&fcaps->fc_rights),
1963 ("%s: invalid rights", func));
1964 KASSERT((fcaps->fc_fcntls & ~CAP_FCNTL_ALL) == 0,
1965 ("%s: invalid fcntls", func));
1966 KASSERT(fcaps->fc_fcntls == 0 ||
1967 cap_rights_is_set(&fcaps->fc_rights, CAP_FCNTL),
1968 ("%s: fcntls without CAP_FCNTL", func));
1969 /*
1970 * open calls without WANTIOCTLCAPS free caps but leave the counter
1971 */
1972 #if 0
1973 KASSERT(fcaps->fc_ioctls != NULL ? fcaps->fc_nioctls > 0 :
1974 (fcaps->fc_nioctls == -1 || fcaps->fc_nioctls == 0),
1975 ("%s: invalid ioctls", func));
1976 #endif
1977 KASSERT(fcaps->fc_nioctls == 0 ||
1978 cap_rights_is_set(&fcaps->fc_rights, CAP_IOCTL),
1979 ("%s: ioctls without CAP_IOCTL", func));
1980 }
1981
1982 static void
fdgrowtable_exp(struct filedesc * fdp,int nfd)1983 fdgrowtable_exp(struct filedesc *fdp, int nfd)
1984 {
1985 int nfd1;
1986
1987 FILEDESC_XLOCK_ASSERT(fdp);
1988
1989 nfd1 = fdp->fd_nfiles * 2;
1990 if (nfd1 < nfd)
1991 nfd1 = nfd;
1992 fdgrowtable(fdp, nfd1);
1993 }
1994
1995 /*
1996 * Grow the file table to accommodate (at least) nfd descriptors.
1997 */
1998 static void
fdgrowtable(struct filedesc * fdp,int nfd)1999 fdgrowtable(struct filedesc *fdp, int nfd)
2000 {
2001 struct filedesc0 *fdp0;
2002 struct freetable *ft;
2003 struct fdescenttbl *ntable;
2004 struct fdescenttbl *otable;
2005 int nnfiles, onfiles;
2006 NDSLOTTYPE *nmap, *omap;
2007
2008 KASSERT(fdp->fd_nfiles > 0, ("zero-length file table"));
2009 KASSERT(fdp->fd_nfiles >= NDFILE, ("file table of length %d shorter "
2010 "than NDFILE (%d)", fdp->fd_nfiles, NDFILE));
2011 KASSERT(fdp->fd_nfiles == NDFILE || fdp->fd_nfiles % NDENTRIES == 0,
2012 ("file table of length %d should be multiple of NDENTRIES (%zu)",
2013 fdp->fd_nfiles, NDENTRIES));
2014 KASSERT((fdp->fd_nfiles == NDFILE) == ((intptr_t)fdp->fd_files -
2015 offsetof(struct filedesc0, fd_dfiles) == (intptr_t)fdp -
2016 offsetof(struct filedesc0, fd_fd)), ("file table of length %d "
2017 "should have %s table", fdp->fd_nfiles, fdp->fd_nfiles == NDFILE ?
2018 "initial" : "dynamic"));
2019 KASSERT((NDSLOTS(fdp->fd_nfiles) <= NDSLOTS(NDFILE)) == ((intptr_t)
2020 fdp->fd_map - offsetof(struct filedesc0, fd_dmap) == (intptr_t)fdp -
2021 offsetof(struct filedesc0, fd_fd)), ("file table of length %d "
2022 "should have %s map", fdp->fd_nfiles, NDSLOTS(fdp->fd_nfiles) <=
2023 NDSLOTS(NDFILE) ? "initial" : "dynamic"));
2024
2025 /* save old values */
2026 onfiles = fdp->fd_nfiles;
2027 otable = fdp->fd_files;
2028 omap = fdp->fd_map;
2029
2030 /* compute the size of the new table */
2031 nnfiles = NDSLOTS(nfd) * NDENTRIES; /* round up */
2032 if (nnfiles <= onfiles)
2033 /* the table is already large enough */
2034 return;
2035
2036 /*
2037 * Allocate a new table. We need enough space for the number of
2038 * entries, file entries themselves and the struct freetable we will use
2039 * when we decommission the table and place it on the freelist.
2040 * We place the struct freetable in the middle so we don't have
2041 * to worry about padding.
2042 */
2043 ntable = malloc(offsetof(struct fdescenttbl, fdt_ofiles) +
2044 nnfiles * sizeof(ntable->fdt_ofiles[0]) +
2045 sizeof(struct freetable),
2046 M_FILEDESC, M_ZERO | M_WAITOK);
2047 /* copy the old data */
2048 ntable->fdt_nfiles = nnfiles;
2049 memcpy(ntable->fdt_ofiles, otable->fdt_ofiles,
2050 onfiles * sizeof(ntable->fdt_ofiles[0]));
2051
2052 /*
2053 * Allocate a new map only if the old one is not large enough.
2054 *
2055 * The initial struct filedesc0 object contains a table and map sized
2056 * for NDFILE (20) entries which means the initial map can accomodate
2057 * up to NDENTRIES (32 or 64) before requiring reallocation.
2058 *
2059 * As the new table size (nnfiles) is always rounded up to a multiple
2060 * of NDENTRIES, the map will be fully utilised following the first
2061 * enlargement, whether it is still the initial map (which will be the
2062 * case if nnfiles == NDENTRIES) or if a new one that has has been
2063 * allocated (which will be the case if nnfiles == X*NDENTRIES for some
2064 * X > 1). In either case, subsequent enlargements will always allocate
2065 * a new map to go along with the new table.
2066 */
2067 if (NDSLOTS(nnfiles) > NDSLOTS(onfiles)) {
2068 nmap = malloc(NDSLOTS(nnfiles) * NDSLOTSIZE, M_FILEDESC,
2069 M_ZERO | M_WAITOK);
2070 /* copy over the old data and update the pointer */
2071 memcpy(nmap, omap, NDSLOTS(onfiles) * sizeof(*omap));
2072 fdp->fd_map = nmap;
2073 } else {
2074 nmap = NULL;
2075 }
2076
2077 /*
2078 * Make sure that ntable is correctly initialized before we replace
2079 * fd_files poiner. Otherwise fget_unlocked() may see inconsistent
2080 * data.
2081 */
2082 atomic_store_rel_ptr((volatile void *)&fdp->fd_files, (uintptr_t)ntable);
2083
2084 /*
2085 * Free the old file table when not shared by other threads or processes.
2086 * The old file table is considered to be shared when either are true:
2087 * - The process has more than one thread.
2088 * - The file descriptor table has been shared via fdshare().
2089 *
2090 * When shared, the old file table will be placed on a freelist
2091 * which will be processed when the struct filedesc is released.
2092 *
2093 * Note that if onfiles == NDFILE, we're dealing with the original
2094 * static allocation contained within (struct filedesc0 *)fdp,
2095 * which must not be freed.
2096 */
2097 if (onfiles > NDFILE) {
2098 /*
2099 * Note we may be called here from fdinit while allocating a
2100 * table for a new process in which case ->p_fd points
2101 * elsewhere.
2102 */
2103 if (curproc->p_fd != fdp || FILEDESC_IS_ONLY_USER(fdp)) {
2104 free(otable, M_FILEDESC);
2105 } else {
2106 ft = (struct freetable *)&otable->fdt_ofiles[onfiles];
2107 fdp0 = (struct filedesc0 *)fdp;
2108 ft->ft_table = otable;
2109 SLIST_INSERT_HEAD(&fdp0->fd_free, ft, ft_next);
2110 }
2111 }
2112 /*
2113 * The map does not have the same possibility of threads still
2114 * holding references to it. So always free it as long as it
2115 * does not reference the original static allocation and a new
2116 * map was allocated.
2117 */
2118 if (nmap != NULL && NDSLOTS(onfiles) > NDSLOTS(NDFILE))
2119 free(omap, M_FILEDESC);
2120 }
2121
2122 /*
2123 * Allocate a file descriptor for the process.
2124 */
2125 int
fdalloc(struct thread * td,int minfd,int * result)2126 fdalloc(struct thread *td, int minfd, int *result)
2127 {
2128 struct proc *p = td->td_proc;
2129 struct filedesc *fdp = p->p_fd;
2130 int fd, maxfd, allocfd;
2131 #ifdef RACCT
2132 int error;
2133 #endif
2134
2135 FILEDESC_XLOCK_ASSERT(fdp);
2136
2137 if (fdp->fd_freefile > minfd)
2138 minfd = fdp->fd_freefile;
2139
2140 maxfd = getmaxfd(td);
2141
2142 /*
2143 * Search the bitmap for a free descriptor starting at minfd.
2144 * If none is found, grow the file table.
2145 */
2146 fd = fd_first_free(fdp, minfd, fdp->fd_nfiles);
2147 if (__predict_false(fd >= maxfd))
2148 return (EMFILE);
2149 if (__predict_false(fd >= fdp->fd_nfiles)) {
2150 allocfd = min(fd * 2, maxfd);
2151 #ifdef RACCT
2152 if (RACCT_ENABLED()) {
2153 error = racct_set_unlocked(p, RACCT_NOFILE, allocfd);
2154 if (error != 0)
2155 return (EMFILE);
2156 }
2157 #endif
2158 /*
2159 * fd is already equal to first free descriptor >= minfd, so
2160 * we only need to grow the table and we are done.
2161 */
2162 fdgrowtable_exp(fdp, allocfd);
2163 }
2164
2165 /*
2166 * Perform some sanity checks, then mark the file descriptor as
2167 * used and return it to the caller.
2168 */
2169 KASSERT(fd >= 0 && fd < min(maxfd, fdp->fd_nfiles),
2170 ("invalid descriptor %d", fd));
2171 KASSERT(!fdisused(fdp, fd),
2172 ("fd_first_free() returned non-free descriptor"));
2173 KASSERT(fdp->fd_ofiles[fd].fde_file == NULL,
2174 ("file descriptor isn't free"));
2175 fdused(fdp, fd);
2176 *result = fd;
2177 return (0);
2178 }
2179
2180 /*
2181 * Allocate n file descriptors for the process.
2182 */
2183 int
fdallocn(struct thread * td,int minfd,int * fds,int n)2184 fdallocn(struct thread *td, int minfd, int *fds, int n)
2185 {
2186 struct proc *p = td->td_proc;
2187 struct filedesc *fdp = p->p_fd;
2188 int i;
2189
2190 FILEDESC_XLOCK_ASSERT(fdp);
2191
2192 for (i = 0; i < n; i++)
2193 if (fdalloc(td, 0, &fds[i]) != 0)
2194 break;
2195
2196 if (i < n) {
2197 for (i--; i >= 0; i--)
2198 fdunused(fdp, fds[i]);
2199 return (EMFILE);
2200 }
2201
2202 return (0);
2203 }
2204
2205 /*
2206 * Create a new open file structure and allocate a file descriptor for the
2207 * process that refers to it. We add one reference to the file for the
2208 * descriptor table and one reference for resultfp. This is to prevent us
2209 * being preempted and the entry in the descriptor table closed after we
2210 * release the FILEDESC lock.
2211 */
2212 int
falloc_caps(struct thread * td,struct file ** resultfp,int * resultfd,int flags,struct filecaps * fcaps)2213 falloc_caps(struct thread *td, struct file **resultfp, int *resultfd, int flags,
2214 struct filecaps *fcaps)
2215 {
2216 struct file *fp;
2217 int error, fd;
2218
2219 MPASS(resultfp != NULL);
2220 MPASS(resultfd != NULL);
2221
2222 error = _falloc_noinstall(td, &fp, 2);
2223 if (__predict_false(error != 0)) {
2224 return (error);
2225 }
2226
2227 error = finstall_refed(td, fp, &fd, flags, fcaps);
2228 if (__predict_false(error != 0)) {
2229 falloc_abort(td, fp);
2230 return (error);
2231 }
2232
2233 *resultfp = fp;
2234 *resultfd = fd;
2235
2236 return (0);
2237 }
2238
2239 /*
2240 * Create a new open file structure without allocating a file descriptor.
2241 */
2242 int
_falloc_noinstall(struct thread * td,struct file ** resultfp,u_int n)2243 _falloc_noinstall(struct thread *td, struct file **resultfp, u_int n)
2244 {
2245 struct file *fp;
2246 int maxuserfiles = maxfiles - (maxfiles / 20);
2247 int openfiles_new;
2248 static struct timeval lastfail;
2249 static int curfail;
2250
2251 KASSERT(resultfp != NULL, ("%s: resultfp == NULL", __func__));
2252 MPASS(n > 0);
2253
2254 openfiles_new = atomic_fetchadd_int(&openfiles, 1) + 1;
2255 if ((openfiles_new >= maxuserfiles &&
2256 priv_check(td, PRIV_MAXFILES) != 0) ||
2257 openfiles_new >= maxfiles) {
2258 atomic_subtract_int(&openfiles, 1);
2259 if (ppsratecheck(&lastfail, &curfail, 1)) {
2260 printf("kern.maxfiles limit exceeded by uid %i, (%s) "
2261 "please see tuning(7).\n", td->td_ucred->cr_ruid, td->td_proc->p_comm);
2262 }
2263 return (ENFILE);
2264 }
2265 fp = uma_zalloc(file_zone, M_WAITOK);
2266 bzero(fp, sizeof(*fp));
2267 refcount_init(&fp->f_count, n);
2268 fp->f_cred = crhold(td->td_ucred);
2269 fp->f_ops = &badfileops;
2270 *resultfp = fp;
2271 return (0);
2272 }
2273
2274 void
falloc_abort(struct thread * td,struct file * fp)2275 falloc_abort(struct thread *td, struct file *fp)
2276 {
2277
2278 /*
2279 * For assertion purposes.
2280 */
2281 refcount_init(&fp->f_count, 0);
2282 _fdrop(fp, td);
2283 }
2284
2285 /*
2286 * Install a file in a file descriptor table.
2287 */
2288 void
_finstall(struct filedesc * fdp,struct file * fp,int fd,int flags,struct filecaps * fcaps)2289 _finstall(struct filedesc *fdp, struct file *fp, int fd, int flags,
2290 struct filecaps *fcaps)
2291 {
2292 struct filedescent *fde;
2293
2294 MPASS(fp != NULL);
2295 if (fcaps != NULL)
2296 filecaps_validate(fcaps, __func__);
2297 FILEDESC_XLOCK_ASSERT(fdp);
2298
2299 fde = &fdp->fd_ofiles[fd];
2300 #ifdef CAPABILITIES
2301 seqc_write_begin(&fde->fde_seqc);
2302 #endif
2303 fde->fde_file = fp;
2304 fde->fde_flags = open_to_fde_flags(flags, true);
2305 if (fcaps != NULL)
2306 filecaps_move(fcaps, &fde->fde_caps);
2307 else
2308 filecaps_fill(&fde->fde_caps);
2309 #ifdef CAPABILITIES
2310 seqc_write_end(&fde->fde_seqc);
2311 #endif
2312 }
2313
2314 int
finstall_refed(struct thread * td,struct file * fp,int * fd,int flags,struct filecaps * fcaps)2315 finstall_refed(struct thread *td, struct file *fp, int *fd, int flags,
2316 struct filecaps *fcaps)
2317 {
2318 struct filedesc *fdp = td->td_proc->p_fd;
2319 int error;
2320
2321 MPASS(fd != NULL);
2322
2323 FILEDESC_XLOCK(fdp);
2324 error = fdalloc(td, 0, fd);
2325 if (__predict_true(error == 0)) {
2326 _finstall(fdp, fp, *fd, flags, fcaps);
2327 }
2328 FILEDESC_XUNLOCK(fdp);
2329 return (error);
2330 }
2331
2332 int
finstall(struct thread * td,struct file * fp,int * fd,int flags,struct filecaps * fcaps)2333 finstall(struct thread *td, struct file *fp, int *fd, int flags,
2334 struct filecaps *fcaps)
2335 {
2336 int error;
2337
2338 MPASS(fd != NULL);
2339
2340 if (!fhold(fp))
2341 return (EBADF);
2342 error = finstall_refed(td, fp, fd, flags, fcaps);
2343 if (__predict_false(error != 0)) {
2344 fdrop(fp, td);
2345 }
2346 return (error);
2347 }
2348
2349 /*
2350 * Build a new filedesc structure from another.
2351 *
2352 * If fdp is not NULL, return with it shared locked.
2353 */
2354 struct filedesc *
fdinit(void)2355 fdinit(void)
2356 {
2357 struct filedesc0 *newfdp0;
2358 struct filedesc *newfdp;
2359
2360 newfdp0 = uma_zalloc(filedesc0_zone, M_WAITOK | M_ZERO);
2361 newfdp = &newfdp0->fd_fd;
2362
2363 /* Create the file descriptor table. */
2364 FILEDESC_LOCK_INIT(newfdp);
2365 refcount_init(&newfdp->fd_refcnt, 1);
2366 refcount_init(&newfdp->fd_holdcnt, 1);
2367 newfdp->fd_map = newfdp0->fd_dmap;
2368 newfdp->fd_files = (struct fdescenttbl *)&newfdp0->fd_dfiles;
2369 newfdp->fd_files->fdt_nfiles = NDFILE;
2370
2371 return (newfdp);
2372 }
2373
2374 /*
2375 * Build a pwddesc structure from another.
2376 * Copy the current, root, and jail root vnode references.
2377 *
2378 * If pdp is not NULL and keeplock is true, return with it (exclusively) locked.
2379 */
2380 struct pwddesc *
pdinit(struct pwddesc * pdp,bool keeplock)2381 pdinit(struct pwddesc *pdp, bool keeplock)
2382 {
2383 struct pwddesc *newpdp;
2384 struct pwd *newpwd;
2385
2386 newpdp = malloc(sizeof(*newpdp), M_PWDDESC, M_WAITOK | M_ZERO);
2387
2388 PWDDESC_LOCK_INIT(newpdp);
2389 refcount_init(&newpdp->pd_refcount, 1);
2390 newpdp->pd_cmask = CMASK;
2391
2392 if (pdp == NULL) {
2393 newpwd = pwd_alloc();
2394 smr_serialized_store(&newpdp->pd_pwd, newpwd, true);
2395 return (newpdp);
2396 }
2397
2398 PWDDESC_XLOCK(pdp);
2399 newpwd = pwd_hold_pwddesc(pdp);
2400 smr_serialized_store(&newpdp->pd_pwd, newpwd, true);
2401 if (!keeplock)
2402 PWDDESC_XUNLOCK(pdp);
2403 return (newpdp);
2404 }
2405
2406 /*
2407 * Hold either filedesc or pwddesc of the passed process.
2408 *
2409 * The process lock is used to synchronize against the target exiting and
2410 * freeing the data.
2411 *
2412 * Clearing can be ilustrated in 3 steps:
2413 * 1. set the pointer to NULL. Either routine can race against it, hence
2414 * atomic_load_ptr.
2415 * 2. observe the process lock as not taken. Until then fdhold/pdhold can
2416 * race to either still see the pointer or find NULL. It is still safe to
2417 * grab a reference as clearing is stalled.
2418 * 3. after the lock is observed as not taken, any fdhold/pdhold calls are
2419 * guaranteed to see NULL, making it safe to finish clearing
2420 */
2421 static struct filedesc *
fdhold(struct proc * p)2422 fdhold(struct proc *p)
2423 {
2424 struct filedesc *fdp;
2425
2426 PROC_LOCK_ASSERT(p, MA_OWNED);
2427 fdp = atomic_load_ptr(&p->p_fd);
2428 if (fdp != NULL)
2429 refcount_acquire(&fdp->fd_holdcnt);
2430 return (fdp);
2431 }
2432
2433 static struct pwddesc *
pdhold(struct proc * p)2434 pdhold(struct proc *p)
2435 {
2436 struct pwddesc *pdp;
2437
2438 PROC_LOCK_ASSERT(p, MA_OWNED);
2439 pdp = atomic_load_ptr(&p->p_pd);
2440 if (pdp != NULL)
2441 refcount_acquire(&pdp->pd_refcount);
2442 return (pdp);
2443 }
2444
2445 static void
fddrop(struct filedesc * fdp)2446 fddrop(struct filedesc *fdp)
2447 {
2448
2449 if (refcount_load(&fdp->fd_holdcnt) > 1) {
2450 if (refcount_release(&fdp->fd_holdcnt) == 0)
2451 return;
2452 }
2453
2454 FILEDESC_LOCK_DESTROY(fdp);
2455 uma_zfree(filedesc0_zone, fdp);
2456 }
2457
2458 static void
pddrop(struct pwddesc * pdp)2459 pddrop(struct pwddesc *pdp)
2460 {
2461 struct pwd *pwd;
2462
2463 if (refcount_release_if_not_last(&pdp->pd_refcount))
2464 return;
2465
2466 PWDDESC_XLOCK(pdp);
2467 if (refcount_release(&pdp->pd_refcount) == 0) {
2468 PWDDESC_XUNLOCK(pdp);
2469 return;
2470 }
2471 pwd = PWDDESC_XLOCKED_LOAD_PWD(pdp);
2472 pwd_set(pdp, NULL);
2473 PWDDESC_XUNLOCK(pdp);
2474 pwd_drop(pwd);
2475
2476 PWDDESC_LOCK_DESTROY(pdp);
2477 free(pdp, M_PWDDESC);
2478 }
2479
2480 /*
2481 * Share a filedesc structure.
2482 */
2483 struct filedesc *
fdshare(struct filedesc * fdp)2484 fdshare(struct filedesc *fdp)
2485 {
2486
2487 refcount_acquire(&fdp->fd_refcnt);
2488 return (fdp);
2489 }
2490
2491 /*
2492 * Share a pwddesc structure.
2493 */
2494 struct pwddesc *
pdshare(struct pwddesc * pdp)2495 pdshare(struct pwddesc *pdp)
2496 {
2497 refcount_acquire(&pdp->pd_refcount);
2498 return (pdp);
2499 }
2500
2501 /*
2502 * Unshare a filedesc structure, if necessary by making a copy
2503 */
2504 void
fdunshare(struct thread * td)2505 fdunshare(struct thread *td)
2506 {
2507 struct filedesc *tmp;
2508 struct proc *p = td->td_proc;
2509
2510 if (refcount_load(&p->p_fd->fd_refcnt) == 1)
2511 return;
2512
2513 tmp = fdcopy(p->p_fd, p);
2514 fdescfree(td);
2515 p->p_fd = tmp;
2516 }
2517
2518 /*
2519 * Unshare a pwddesc structure.
2520 */
2521 void
pdunshare(struct thread * td)2522 pdunshare(struct thread *td)
2523 {
2524 struct pwddesc *pdp;
2525 struct proc *p;
2526
2527 p = td->td_proc;
2528 /* Not shared. */
2529 if (refcount_load(&p->p_pd->pd_refcount) == 1)
2530 return;
2531
2532 pdp = pdcopy(p->p_pd);
2533 pdescfree(td);
2534 p->p_pd = pdp;
2535 }
2536
2537 /*
2538 * Copy a filedesc structure. A NULL pointer in returns a NULL reference,
2539 * this is to ease callers, not catch errors.
2540 */
2541 struct filedesc *
fdcopy(struct filedesc * fdp,struct proc * p1)2542 fdcopy(struct filedesc *fdp, struct proc *p1)
2543 {
2544 struct filedesc *newfdp;
2545 struct filedescent *nfde, *ofde;
2546 struct file *fp;
2547 int i, lastfile;
2548 bool fork_pass;
2549
2550 MPASS(fdp != NULL);
2551
2552 fork_pass = false;
2553 newfdp = fdinit();
2554 FILEDESC_SLOCK(fdp);
2555 for (;;) {
2556 lastfile = fdlastfile(fdp);
2557 if (lastfile < newfdp->fd_nfiles)
2558 break;
2559 FILEDESC_SUNLOCK(fdp);
2560 fdgrowtable(newfdp, lastfile + 1);
2561 FILEDESC_SLOCK(fdp);
2562 }
2563
2564 /*
2565 * Copy all passable descriptors (i.e. not kqueue), and
2566 * prepare to handle copyable but not passable descriptors
2567 * (kqueues).
2568 *
2569 * The pass to handle copying is performed after all passable
2570 * files are installed into the new file descriptor's table,
2571 * since kqueues need all referenced file descriptors already
2572 * valid, including other kqueues. For the same reason the
2573 * copying is done in two passes by itself, first installing
2574 * not fully initialized ('empty') copyable files into the new
2575 * fd table, and then giving the subsystems a second chance to
2576 * really fill the copied file backing structure with the
2577 * content.
2578 */
2579 newfdp->fd_freefile = fdp->fd_freefile;
2580 FILEDESC_FOREACH_FDE(fdp, i, ofde) {
2581 const struct fileops *ops;
2582
2583 ops = ofde->fde_file->f_ops;
2584 fp = NULL;
2585 if ((ops->fo_flags & DFLAG_FORK) != 0 &&
2586 (ofde->fde_flags & UF_FOCLOSE) == 0) {
2587 if (ops->fo_fork(newfdp, ofde->fde_file, &fp, p1,
2588 curthread) != 0)
2589 continue;
2590 fork_pass = true;
2591 } else if ((ops->fo_flags & DFLAG_PASSABLE) == 0 ||
2592 (ofde->fde_flags & UF_FOCLOSE) != 0 ||
2593 !fhold(ofde->fde_file)) {
2594 if (newfdp->fd_freefile == fdp->fd_freefile)
2595 newfdp->fd_freefile = i;
2596 continue;
2597 }
2598 nfde = &newfdp->fd_ofiles[i];
2599 *nfde = *ofde;
2600 if (fp != NULL)
2601 nfde->fde_file = fp;
2602 filecaps_copy(&ofde->fde_caps, &nfde->fde_caps, true);
2603 fdused_init(newfdp, i);
2604 }
2605 MPASS(newfdp->fd_freefile != -1);
2606 FILEDESC_SUNLOCK(fdp);
2607
2608 /*
2609 * Now handle copying kqueues, since all fds, including
2610 * kqueues, are in place.
2611 */
2612 if (__predict_false(fork_pass)) {
2613 FILEDESC_FOREACH_FDE(newfdp, i, nfde) {
2614 const struct fileops *ops;
2615
2616 ops = nfde->fde_file->f_ops;
2617 if ((ops->fo_flags & DFLAG_FORK) == 0 ||
2618 nfde->fde_file == NULL)
2619 continue;
2620 ops->fo_fork(newfdp, NULL, &nfde->fde_file, p1,
2621 curthread);
2622 }
2623 }
2624 return (newfdp);
2625 }
2626
2627 /*
2628 * Copy a pwddesc structure.
2629 */
2630 struct pwddesc *
pdcopy(struct pwddesc * pdp)2631 pdcopy(struct pwddesc *pdp)
2632 {
2633 struct pwddesc *newpdp;
2634
2635 MPASS(pdp != NULL);
2636
2637 newpdp = pdinit(pdp, true);
2638 newpdp->pd_cmask = pdp->pd_cmask;
2639 PWDDESC_XUNLOCK(pdp);
2640 return (newpdp);
2641 }
2642
2643 /*
2644 * Clear POSIX style locks. This is only used when fdp looses a reference (i.e.
2645 * one of processes using it exits) and the table used to be shared.
2646 */
2647 static void
fdclearlocks(struct thread * td)2648 fdclearlocks(struct thread *td)
2649 {
2650 struct filedesc *fdp;
2651 struct filedesc_to_leader *fdtol;
2652 struct flock lf;
2653 struct file *fp;
2654 struct proc *p;
2655 struct vnode *vp;
2656 int i;
2657
2658 p = td->td_proc;
2659 fdp = p->p_fd;
2660 fdtol = p->p_fdtol;
2661 MPASS(fdtol != NULL);
2662
2663 FILEDESC_XLOCK(fdp);
2664 KASSERT(fdtol->fdl_refcount > 0,
2665 ("filedesc_to_refcount botch: fdl_refcount=%d",
2666 fdtol->fdl_refcount));
2667 if (fdtol->fdl_refcount == 1 &&
2668 (p->p_leader->p_flag & P_ADVLOCK) != 0) {
2669 FILEDESC_FOREACH_FP(fdp, i, fp) {
2670 if (fp->f_type != DTYPE_VNODE ||
2671 !fhold(fp))
2672 continue;
2673 FILEDESC_XUNLOCK(fdp);
2674 lf.l_whence = SEEK_SET;
2675 lf.l_start = 0;
2676 lf.l_len = 0;
2677 lf.l_type = F_UNLCK;
2678 vp = fp->f_vnode;
2679 (void) VOP_ADVLOCK(vp,
2680 (caddr_t)p->p_leader, F_UNLCK,
2681 &lf, F_POSIX);
2682 FILEDESC_XLOCK(fdp);
2683 fdrop(fp, td);
2684 }
2685 }
2686 retry:
2687 if (fdtol->fdl_refcount == 1) {
2688 if (fdp->fd_holdleaderscount > 0 &&
2689 (p->p_leader->p_flag & P_ADVLOCK) != 0) {
2690 /*
2691 * close() or kern_dup() has cleared a reference
2692 * in a shared file descriptor table.
2693 */
2694 fdp->fd_holdleaderswakeup = 1;
2695 sx_sleep(&fdp->fd_holdleaderscount,
2696 FILEDESC_LOCK(fdp), PLOCK, "fdlhold", 0);
2697 goto retry;
2698 }
2699 if (fdtol->fdl_holdcount > 0) {
2700 /*
2701 * Ensure that fdtol->fdl_leader remains
2702 * valid in closef().
2703 */
2704 fdtol->fdl_wakeup = 1;
2705 sx_sleep(fdtol, FILEDESC_LOCK(fdp), PLOCK,
2706 "fdlhold", 0);
2707 goto retry;
2708 }
2709 }
2710 fdtol->fdl_refcount--;
2711 if (fdtol->fdl_refcount == 0 &&
2712 fdtol->fdl_holdcount == 0) {
2713 fdtol->fdl_next->fdl_prev = fdtol->fdl_prev;
2714 fdtol->fdl_prev->fdl_next = fdtol->fdl_next;
2715 } else
2716 fdtol = NULL;
2717 p->p_fdtol = NULL;
2718 FILEDESC_XUNLOCK(fdp);
2719 if (fdtol != NULL)
2720 free(fdtol, M_FILEDESC_TO_LEADER);
2721 }
2722
2723 /*
2724 * Release a filedesc structure.
2725 */
2726 static void
fdescfree_fds(struct thread * td,struct filedesc * fdp)2727 fdescfree_fds(struct thread *td, struct filedesc *fdp)
2728 {
2729 struct filedesc0 *fdp0;
2730 struct freetable *ft, *tft;
2731 struct filedescent *fde;
2732 struct file *fp;
2733 int i;
2734
2735 KASSERT(refcount_load(&fdp->fd_refcnt) == 0,
2736 ("%s: fd table %p carries references", __func__, fdp));
2737
2738 /*
2739 * Serialize with threads iterating over the table, if any.
2740 */
2741 if (refcount_load(&fdp->fd_holdcnt) > 1) {
2742 FILEDESC_XLOCK(fdp);
2743 FILEDESC_XUNLOCK(fdp);
2744 }
2745
2746 FILEDESC_FOREACH_FDE(fdp, i, fde) {
2747 fp = fde->fde_file;
2748 fdefree_last(fde);
2749 (void) closef(fp, td);
2750 }
2751
2752 if (NDSLOTS(fdp->fd_nfiles) > NDSLOTS(NDFILE))
2753 free(fdp->fd_map, M_FILEDESC);
2754 if (fdp->fd_nfiles > NDFILE)
2755 free(fdp->fd_files, M_FILEDESC);
2756
2757 fdp0 = (struct filedesc0 *)fdp;
2758 SLIST_FOREACH_SAFE(ft, &fdp0->fd_free, ft_next, tft)
2759 free(ft->ft_table, M_FILEDESC);
2760
2761 fddrop(fdp);
2762 }
2763
2764 void
fdescfree(struct thread * td)2765 fdescfree(struct thread *td)
2766 {
2767 struct proc *p;
2768 struct filedesc *fdp;
2769
2770 p = td->td_proc;
2771 fdp = p->p_fd;
2772 MPASS(fdp != NULL);
2773
2774 #ifdef RACCT
2775 if (RACCT_ENABLED())
2776 racct_set_unlocked(p, RACCT_NOFILE, 0);
2777 #endif
2778
2779 if (p->p_fdtol != NULL)
2780 fdclearlocks(td);
2781
2782 /*
2783 * Check fdhold for an explanation.
2784 */
2785 atomic_store_ptr(&p->p_fd, NULL);
2786 atomic_thread_fence_seq_cst();
2787 PROC_WAIT_UNLOCKED(p);
2788
2789 if (refcount_release(&fdp->fd_refcnt) == 0)
2790 return;
2791
2792 fdescfree_fds(td, fdp);
2793 }
2794
2795 void
pdescfree(struct thread * td)2796 pdescfree(struct thread *td)
2797 {
2798 struct proc *p;
2799 struct pwddesc *pdp;
2800
2801 p = td->td_proc;
2802 pdp = p->p_pd;
2803 MPASS(pdp != NULL);
2804
2805 /*
2806 * Check pdhold for an explanation.
2807 */
2808 atomic_store_ptr(&p->p_pd, NULL);
2809 atomic_thread_fence_seq_cst();
2810 PROC_WAIT_UNLOCKED(p);
2811
2812 pddrop(pdp);
2813 }
2814
2815 /*
2816 * For setugid programs, we don't want to people to use that setugidness
2817 * to generate error messages which write to a file which otherwise would
2818 * otherwise be off-limits to the process. We check for filesystems where
2819 * the vnode can change out from under us after execve (like [lin]procfs).
2820 *
2821 * Since fdsetugidsafety calls this only for fd 0, 1 and 2, this check is
2822 * sufficient. We also don't check for setugidness since we know we are.
2823 */
2824 static bool
is_unsafe(struct file * fp)2825 is_unsafe(struct file *fp)
2826 {
2827 struct vnode *vp;
2828
2829 if (fp->f_type != DTYPE_VNODE)
2830 return (false);
2831
2832 vp = fp->f_vnode;
2833 return ((vp->v_vflag & VV_PROCDEP) != 0);
2834 }
2835
2836 /*
2837 * Make this setguid thing safe, if at all possible.
2838 */
2839 void
fdsetugidsafety(struct thread * td)2840 fdsetugidsafety(struct thread *td)
2841 {
2842 struct filedesc *fdp;
2843 struct file *fp;
2844 int i;
2845
2846 fdp = td->td_proc->p_fd;
2847 KASSERT(refcount_load(&fdp->fd_refcnt) == 1,
2848 ("the fdtable should not be shared"));
2849 MPASS(fdp->fd_nfiles >= 3);
2850 for (i = 0; i <= 2; i++) {
2851 fp = fdp->fd_ofiles[i].fde_file;
2852 if (fp != NULL && is_unsafe(fp)) {
2853 FILEDESC_XLOCK(fdp);
2854 knote_fdclose(td, i);
2855 /*
2856 * NULL-out descriptor prior to close to avoid
2857 * a race while close blocks.
2858 */
2859 fdfree(fdp, i);
2860 FILEDESC_XUNLOCK(fdp);
2861 (void) closef(fp, td);
2862 }
2863 }
2864 }
2865
2866 /*
2867 * If a specific file object occupies a specific file descriptor, close the
2868 * file descriptor entry and drop a reference on the file object. This is a
2869 * convenience function to handle a subsequent error in a function that calls
2870 * falloc() that handles the race that another thread might have closed the
2871 * file descriptor out from under the thread creating the file object.
2872 */
2873 void
fdclose(struct thread * td,struct file * fp,int idx)2874 fdclose(struct thread *td, struct file *fp, int idx)
2875 {
2876 struct filedesc *fdp = td->td_proc->p_fd;
2877
2878 FILEDESC_XLOCK(fdp);
2879 if (fdp->fd_ofiles[idx].fde_file == fp) {
2880 fdfree(fdp, idx);
2881 FILEDESC_XUNLOCK(fdp);
2882 fdrop(fp, td);
2883 } else
2884 FILEDESC_XUNLOCK(fdp);
2885 }
2886
2887 /*
2888 * Close any files on exec?
2889 */
2890 void
fdcloseexec(struct thread * td)2891 fdcloseexec(struct thread *td)
2892 {
2893 struct filedesc *fdp;
2894 struct filedescent *fde;
2895 struct file *fp;
2896 int i;
2897
2898 fdp = td->td_proc->p_fd;
2899 KASSERT(refcount_load(&fdp->fd_refcnt) == 1,
2900 ("the fdtable should not be shared"));
2901 FILEDESC_FOREACH_FDE(fdp, i, fde) {
2902 fp = fde->fde_file;
2903 if (fp->f_type == DTYPE_MQUEUE ||
2904 (fde->fde_flags & UF_EXCLOSE)) {
2905 FILEDESC_XLOCK(fdp);
2906 fdfree(fdp, i);
2907 (void) closefp(fdp, i, fp, td, false, false);
2908 FILEDESC_UNLOCK_ASSERT(fdp);
2909 } else if (fde->fde_flags & UF_FOCLOSE) {
2910 /*
2911 * https://austingroupbugs.net/view.php?id=1851
2912 * FD_CLOFORK should not be preserved across exec
2913 */
2914 fde->fde_flags &= ~UF_FOCLOSE;
2915 }
2916 }
2917 }
2918
2919 /*
2920 * It is unsafe for set[ug]id processes to be started with file
2921 * descriptors 0..2 closed, as these descriptors are given implicit
2922 * significance in the Standard C library. fdcheckstd() will create a
2923 * descriptor referencing /dev/null for each of stdin, stdout, and
2924 * stderr that is not already open.
2925 */
2926 int
fdcheckstd(struct thread * td)2927 fdcheckstd(struct thread *td)
2928 {
2929 struct filedesc *fdp;
2930 register_t save;
2931 int i, error, devnull;
2932
2933 fdp = td->td_proc->p_fd;
2934 KASSERT(refcount_load(&fdp->fd_refcnt) == 1,
2935 ("the fdtable should not be shared"));
2936 MPASS(fdp->fd_nfiles >= 3);
2937 devnull = -1;
2938 for (i = 0; i <= 2; i++) {
2939 if (fdp->fd_ofiles[i].fde_file != NULL)
2940 continue;
2941
2942 save = td->td_retval[0];
2943 if (devnull != -1) {
2944 error = kern_dup(td, FDDUP_FIXED, 0, devnull, i);
2945 } else {
2946 error = kern_openat(td, AT_FDCWD, "/dev/null",
2947 UIO_SYSSPACE, O_RDWR, 0);
2948 if (error == 0) {
2949 devnull = td->td_retval[0];
2950 KASSERT(devnull == i, ("we didn't get our fd"));
2951 }
2952 }
2953 td->td_retval[0] = save;
2954 if (error != 0)
2955 return (error);
2956 }
2957 return (0);
2958 }
2959
2960 /*
2961 * Internal form of close. Decrement reference count on file structure.
2962 * Note: td may be NULL when closing a file that was being passed in a
2963 * message.
2964 */
2965 int
closef(struct file * fp,struct thread * td)2966 closef(struct file *fp, struct thread *td)
2967 {
2968 struct vnode *vp;
2969 struct flock lf;
2970 struct filedesc_to_leader *fdtol;
2971 struct filedesc *fdp;
2972
2973 MPASS(td != NULL);
2974
2975 /*
2976 * POSIX record locking dictates that any close releases ALL
2977 * locks owned by this process. This is handled by setting
2978 * a flag in the unlock to free ONLY locks obeying POSIX
2979 * semantics, and not to free BSD-style file locks.
2980 * If the descriptor was in a message, POSIX-style locks
2981 * aren't passed with the descriptor, and the thread pointer
2982 * will be NULL. Callers should be careful only to pass a
2983 * NULL thread pointer when there really is no owning
2984 * context that might have locks, or the locks will be
2985 * leaked.
2986 */
2987 if (fp->f_type == DTYPE_VNODE) {
2988 vp = fp->f_vnode;
2989 if ((td->td_proc->p_leader->p_flag & P_ADVLOCK) != 0) {
2990 lf.l_whence = SEEK_SET;
2991 lf.l_start = 0;
2992 lf.l_len = 0;
2993 lf.l_type = F_UNLCK;
2994 (void) VOP_ADVLOCK(vp, (caddr_t)td->td_proc->p_leader,
2995 F_UNLCK, &lf, F_POSIX);
2996 }
2997 fdtol = td->td_proc->p_fdtol;
2998 if (fdtol != NULL) {
2999 /*
3000 * Handle special case where file descriptor table is
3001 * shared between multiple process leaders.
3002 */
3003 fdp = td->td_proc->p_fd;
3004 FILEDESC_XLOCK(fdp);
3005 for (fdtol = fdtol->fdl_next;
3006 fdtol != td->td_proc->p_fdtol;
3007 fdtol = fdtol->fdl_next) {
3008 if ((fdtol->fdl_leader->p_flag &
3009 P_ADVLOCK) == 0)
3010 continue;
3011 fdtol->fdl_holdcount++;
3012 FILEDESC_XUNLOCK(fdp);
3013 lf.l_whence = SEEK_SET;
3014 lf.l_start = 0;
3015 lf.l_len = 0;
3016 lf.l_type = F_UNLCK;
3017 vp = fp->f_vnode;
3018 (void) VOP_ADVLOCK(vp,
3019 (caddr_t)fdtol->fdl_leader, F_UNLCK, &lf,
3020 F_POSIX);
3021 FILEDESC_XLOCK(fdp);
3022 fdtol->fdl_holdcount--;
3023 if (fdtol->fdl_holdcount == 0 &&
3024 fdtol->fdl_wakeup != 0) {
3025 fdtol->fdl_wakeup = 0;
3026 wakeup(fdtol);
3027 }
3028 }
3029 FILEDESC_XUNLOCK(fdp);
3030 }
3031 }
3032 return (fdrop_close(fp, td));
3033 }
3034
3035 /*
3036 * Hack for file descriptor passing code.
3037 */
3038 void
closef_nothread(struct file * fp)3039 closef_nothread(struct file *fp)
3040 {
3041
3042 fdrop(fp, NULL);
3043 }
3044
3045 /*
3046 * Initialize the file pointer with the specified properties.
3047 *
3048 * The ops are set with release semantics to be certain that the flags, type,
3049 * and data are visible when ops is. This is to prevent ops methods from being
3050 * called with bad data.
3051 */
3052 void
finit(struct file * fp,u_int flag,short type,void * data,const struct fileops * ops)3053 finit(struct file *fp, u_int flag, short type, void *data,
3054 const struct fileops *ops)
3055 {
3056 fp->f_data = data;
3057 fp->f_flag = flag;
3058 fp->f_type = type;
3059 atomic_store_rel_ptr((volatile uintptr_t *)&fp->f_ops, (uintptr_t)ops);
3060 }
3061
3062 void
finit_vnode(struct file * fp,u_int flag,void * data,const struct fileops * ops)3063 finit_vnode(struct file *fp, u_int flag, void *data, const struct fileops *ops)
3064 {
3065 fp->f_seqcount[UIO_READ] = 1;
3066 fp->f_seqcount[UIO_WRITE] = 1;
3067 finit(fp, (flag & FMASK) | (fp->f_flag & FHASLOCK), DTYPE_VNODE,
3068 data, ops);
3069 }
3070
3071 int
fget_cap_noref(struct filedesc * fdp,int fd,const cap_rights_t * needrightsp,struct file ** fpp,struct filecaps * havecapsp)3072 fget_cap_noref(struct filedesc *fdp, int fd, const cap_rights_t *needrightsp,
3073 struct file **fpp, struct filecaps *havecapsp)
3074 {
3075 struct filedescent *fde;
3076 int error;
3077
3078 FILEDESC_LOCK_ASSERT(fdp);
3079
3080 *fpp = NULL;
3081 fde = fdeget_noref(fdp, fd);
3082 if (fde == NULL) {
3083 error = EBADF;
3084 goto out;
3085 }
3086
3087 #ifdef CAPABILITIES
3088 error = cap_check(cap_rights_fde_inline(fde), needrightsp);
3089 if (error != 0)
3090 goto out;
3091 #endif
3092
3093 if (havecapsp != NULL)
3094 filecaps_copy(&fde->fde_caps, havecapsp, true);
3095
3096 *fpp = fde->fde_file;
3097
3098 error = 0;
3099 out:
3100 return (error);
3101 }
3102
3103 #ifdef CAPABILITIES
3104 int
fget_cap(struct thread * td,int fd,const cap_rights_t * needrightsp,uint8_t * flagsp,struct file ** fpp,struct filecaps * havecapsp)3105 fget_cap(struct thread *td, int fd, const cap_rights_t *needrightsp,
3106 uint8_t *flagsp, struct file **fpp, struct filecaps *havecapsp)
3107 {
3108 struct filedesc *fdp = td->td_proc->p_fd;
3109 int error;
3110 struct file *fp;
3111 seqc_t seq;
3112
3113 *fpp = NULL;
3114 for (;;) {
3115 error = fget_unlocked_seq(td, fd, needrightsp, flagsp, &fp,
3116 &seq);
3117 if (error != 0)
3118 return (error);
3119
3120 if (havecapsp != NULL) {
3121 if (!filecaps_copy(&fdp->fd_ofiles[fd].fde_caps,
3122 havecapsp, false)) {
3123 fdrop(fp, td);
3124 goto get_locked;
3125 }
3126 }
3127
3128 if (!fd_modified(fdp, fd, seq))
3129 break;
3130 fdrop(fp, td);
3131 }
3132
3133 *fpp = fp;
3134 return (0);
3135
3136 get_locked:
3137 FILEDESC_SLOCK(fdp);
3138 error = fget_cap_noref(fdp, fd, needrightsp, fpp, havecapsp);
3139 if (error == 0 && !fhold(*fpp))
3140 error = EBADF;
3141 FILEDESC_SUNLOCK(fdp);
3142 return (error);
3143 }
3144 #else
3145 int
fget_cap(struct thread * td,int fd,const cap_rights_t * needrightsp,uint8_t * flagsp,struct file ** fpp,struct filecaps * havecapsp)3146 fget_cap(struct thread *td, int fd, const cap_rights_t *needrightsp,
3147 uint8_t *flagsp, struct file **fpp, struct filecaps *havecapsp)
3148 {
3149 int error;
3150 error = fget_unlocked_flags(td, fd, needrightsp, flagsp, fpp);
3151 if (havecapsp != NULL && error == 0)
3152 filecaps_fill(havecapsp);
3153
3154 return (error);
3155 }
3156 #endif
3157
3158 int
fget_remote(struct thread * td,struct proc * p,int fd,struct file ** fpp)3159 fget_remote(struct thread *td, struct proc *p, int fd, struct file **fpp)
3160 {
3161 struct filedesc *fdp;
3162 struct file *fp;
3163 int error;
3164
3165 if (p == td->td_proc) /* curproc */
3166 return (fget_unlocked(td, fd, &cap_no_rights, fpp));
3167
3168 PROC_LOCK(p);
3169 fdp = fdhold(p);
3170 PROC_UNLOCK(p);
3171 if (fdp == NULL)
3172 return (ENOENT);
3173 FILEDESC_SLOCK(fdp);
3174 if (refcount_load(&fdp->fd_refcnt) != 0) {
3175 fp = fget_noref(fdp, fd);
3176 if (fp != NULL && fhold(fp)) {
3177 *fpp = fp;
3178 error = 0;
3179 } else {
3180 error = EBADF;
3181 }
3182 } else {
3183 error = ENOENT;
3184 }
3185 FILEDESC_SUNLOCK(fdp);
3186 fddrop(fdp);
3187 return (error);
3188 }
3189
3190 int
fget_remote_foreach(struct thread * td,struct proc * p,int (* fn)(struct proc *,int,struct file *,void *),void * arg)3191 fget_remote_foreach(struct thread *td, struct proc *p,
3192 int (*fn)(struct proc *, int, struct file *, void *), void *arg)
3193 {
3194 struct filedesc *fdp;
3195 struct fdescenttbl *fdt;
3196 struct file *fp;
3197 int error, error1, fd, highfd;
3198
3199 error = 0;
3200 PROC_LOCK(p);
3201 fdp = fdhold(p);
3202 PROC_UNLOCK(p);
3203 if (fdp == NULL)
3204 return (ENOENT);
3205
3206 FILEDESC_SLOCK(fdp);
3207 if (refcount_load(&fdp->fd_refcnt) != 0) {
3208 fdt = atomic_load_ptr(&fdp->fd_files);
3209 highfd = fdt->fdt_nfiles - 1;
3210 FILEDESC_SUNLOCK(fdp);
3211 } else {
3212 error = ENOENT;
3213 FILEDESC_SUNLOCK(fdp);
3214 goto out;
3215 }
3216
3217 for (fd = 0; fd <= highfd; fd++) {
3218 error1 = fget_remote(td, p, fd, &fp);
3219 if (error1 != 0)
3220 continue;
3221 error = fn(p, fd, fp, arg);
3222 fdrop(fp, td);
3223 if (error != 0)
3224 break;
3225 }
3226 out:
3227 fddrop(fdp);
3228 return (error);
3229 }
3230
3231 #ifdef CAPABILITIES
3232 int
fgetvp_lookup_smr(struct nameidata * ndp,struct vnode ** vpp,int * flagsp)3233 fgetvp_lookup_smr(struct nameidata *ndp, struct vnode **vpp, int *flagsp)
3234 {
3235 const struct filedescent *fde;
3236 const struct fdescenttbl *fdt;
3237 struct filedesc *fdp;
3238 struct file *fp;
3239 struct vnode *vp;
3240 const cap_rights_t *haverights;
3241 cap_rights_t rights;
3242 seqc_t seq;
3243 int fd, flags;
3244
3245 VFS_SMR_ASSERT_ENTERED();
3246
3247 fd = ndp->ni_dirfd;
3248 rights = *ndp->ni_rightsneeded;
3249 cap_rights_set_one(&rights, CAP_LOOKUP);
3250
3251 fdp = curproc->p_fd;
3252 fdt = fdp->fd_files;
3253 if (__predict_false((u_int)fd >= fdt->fdt_nfiles))
3254 return (EBADF);
3255 seq = seqc_read_notmodify(fd_seqc(fdt, fd));
3256 fde = &fdt->fdt_ofiles[fd];
3257 haverights = cap_rights_fde_inline(fde);
3258 fp = fde->fde_file;
3259 if (__predict_false(fp == NULL))
3260 return (EAGAIN);
3261 if (__predict_false(cap_check_inline_transient(haverights, &rights)))
3262 return (EAGAIN);
3263 flags = fp->f_flag & FSEARCH;
3264 flags |= (fde->fde_flags & UF_RESOLVE_BENEATH) != 0 ?
3265 O_RESOLVE_BENEATH : 0;
3266 vp = fp->f_vnode;
3267 if (__predict_false(vp == NULL)) {
3268 return (EAGAIN);
3269 }
3270 if (!filecaps_copy(&fde->fde_caps, &ndp->ni_filecaps, false)) {
3271 return (EAGAIN);
3272 }
3273 /*
3274 * Use an acquire barrier to force re-reading of fdt so it is
3275 * refreshed for verification.
3276 */
3277 atomic_thread_fence_acq();
3278 fdt = fdp->fd_files;
3279 if (__predict_false(!seqc_consistent_no_fence(fd_seqc(fdt, fd), seq)))
3280 return (EAGAIN);
3281 /*
3282 * If file descriptor doesn't have all rights,
3283 * all lookups relative to it must also be
3284 * strictly relative.
3285 *
3286 * Not yet supported by fast path.
3287 */
3288 CAP_ALL(&rights);
3289 if (!cap_rights_contains(&ndp->ni_filecaps.fc_rights, &rights) ||
3290 ndp->ni_filecaps.fc_fcntls != CAP_FCNTL_ALL ||
3291 ndp->ni_filecaps.fc_nioctls != -1) {
3292 #ifdef notyet
3293 ndp->ni_lcf |= NI_LCF_STRICTREL;
3294 #else
3295 return (EAGAIN);
3296 #endif
3297 }
3298 *vpp = vp;
3299 *flagsp = flags;
3300 return (0);
3301 }
3302 #else
3303 int
fgetvp_lookup_smr(struct nameidata * ndp,struct vnode ** vpp,int * flagsp)3304 fgetvp_lookup_smr(struct nameidata *ndp, struct vnode **vpp, int *flagsp)
3305 {
3306 const struct filedescent *fde;
3307 const struct fdescenttbl *fdt;
3308 struct filedesc *fdp;
3309 struct file *fp;
3310 struct vnode *vp;
3311 int fd, flags;
3312
3313 VFS_SMR_ASSERT_ENTERED();
3314
3315 fd = ndp->ni_dirfd;
3316 fdp = curproc->p_fd;
3317 fdt = fdp->fd_files;
3318 if (__predict_false((u_int)fd >= fdt->fdt_nfiles))
3319 return (EBADF);
3320 fde = &fdt->fdt_ofiles[fd];
3321 fp = fde->fde_file;
3322 if (__predict_false(fp == NULL))
3323 return (EAGAIN);
3324 flags = fp->f_flag & FSEARCH;
3325 flags |= (fde->fde_flags & UF_RESOLVE_BENEATH) != 0 ?
3326 O_RESOLVE_BENEATH : 0;
3327 vp = fp->f_vnode;
3328 if (__predict_false(vp == NULL || vp->v_type != VDIR)) {
3329 return (EAGAIN);
3330 }
3331 /*
3332 * Use an acquire barrier to force re-reading of fdt so it is
3333 * refreshed for verification.
3334 */
3335 atomic_thread_fence_acq();
3336 fdt = fdp->fd_files;
3337 if (__predict_false(fp != fdt->fdt_ofiles[fd].fde_file))
3338 return (EAGAIN);
3339 filecaps_fill(&ndp->ni_filecaps);
3340 *vpp = vp;
3341 *flagsp = flags;
3342 return (0);
3343 }
3344 #endif
3345
3346 int
fgetvp_lookup(struct nameidata * ndp,struct vnode ** vpp)3347 fgetvp_lookup(struct nameidata *ndp, struct vnode **vpp)
3348 {
3349 struct thread *td;
3350 struct file *fp;
3351 struct vnode *vp;
3352 struct componentname *cnp;
3353 cap_rights_t rights;
3354 int error;
3355 uint8_t flags;
3356
3357 td = curthread;
3358 rights = *ndp->ni_rightsneeded;
3359 cap_rights_set_one(&rights, CAP_LOOKUP);
3360 cnp = &ndp->ni_cnd;
3361
3362 error = fget_cap(td, ndp->ni_dirfd, &rights, &flags, &fp,
3363 &ndp->ni_filecaps);
3364 if (__predict_false(error != 0))
3365 return (error);
3366 if (__predict_false(fp->f_ops == &badfileops)) {
3367 error = EBADF;
3368 goto out_free;
3369 }
3370 vp = fp->f_vnode;
3371 if (__predict_false(vp == NULL)) {
3372 error = ENOTDIR;
3373 goto out_free;
3374 }
3375 vrefact(vp);
3376 /*
3377 * XXX does not check for VDIR, handled by namei_setup
3378 */
3379 if ((fp->f_flag & FSEARCH) != 0)
3380 cnp->cn_flags |= NOEXECCHECK;
3381 if ((flags & UF_RESOLVE_BENEATH) != 0) {
3382 cnp->cn_flags |= RBENEATH;
3383 ndp->ni_resflags |= NIRES_BENEATH;
3384 }
3385 fdrop(fp, td);
3386
3387 #ifdef CAPABILITIES
3388 /*
3389 * If file descriptor doesn't have all rights,
3390 * all lookups relative to it must also be
3391 * strictly relative.
3392 */
3393 CAP_ALL(&rights);
3394 if (!cap_rights_contains(&ndp->ni_filecaps.fc_rights, &rights) ||
3395 ndp->ni_filecaps.fc_fcntls != CAP_FCNTL_ALL ||
3396 ndp->ni_filecaps.fc_nioctls != -1) {
3397 ndp->ni_lcf |= NI_LCF_STRICTREL;
3398 ndp->ni_resflags |= NIRES_STRICTREL;
3399 }
3400 #endif
3401
3402 /*
3403 * TODO: avoid copying ioctl caps if it can be helped to begin with
3404 */
3405 if ((cnp->cn_flags & WANTIOCTLCAPS) == 0)
3406 filecaps_free_ioctl(&ndp->ni_filecaps);
3407
3408 *vpp = vp;
3409 return (0);
3410
3411 out_free:
3412 filecaps_free(&ndp->ni_filecaps);
3413 fdrop(fp, td);
3414 return (error);
3415 }
3416
3417 /*
3418 * Fetch the descriptor locklessly.
3419 *
3420 * We avoid fdrop() races by never raising a refcount above 0. To accomplish
3421 * this we have to use a cmpset loop rather than an atomic_add. The descriptor
3422 * must be re-verified once we acquire a reference to be certain that the
3423 * identity is still correct and we did not lose a race due to preemption.
3424 *
3425 * Force a reload of fdt when looping. Another thread could reallocate
3426 * the table before this fd was closed, so it is possible that there is
3427 * a stale fp pointer in cached version.
3428 */
3429 #ifdef CAPABILITIES
3430 static int
fget_unlocked_seq(struct thread * td,int fd,const cap_rights_t * needrightsp,uint8_t * flagsp,struct file ** fpp,seqc_t * seqp)3431 fget_unlocked_seq(struct thread *td, int fd, const cap_rights_t *needrightsp,
3432 uint8_t *flagsp, struct file **fpp, seqc_t *seqp)
3433 {
3434 struct filedesc *fdp;
3435 const struct filedescent *fde;
3436 const struct fdescenttbl *fdt;
3437 struct file *fp;
3438 seqc_t seq;
3439 cap_rights_t haverights;
3440 int error;
3441 uint8_t flags;
3442
3443 fdp = td->td_proc->p_fd;
3444 fdt = fdp->fd_files;
3445 if (__predict_false((u_int)fd >= fdt->fdt_nfiles))
3446 return (EBADF);
3447
3448 for (;;) {
3449 seq = seqc_read_notmodify(fd_seqc(fdt, fd));
3450 fde = &fdt->fdt_ofiles[fd];
3451 haverights = *cap_rights_fde_inline(fde);
3452 fp = fde->fde_file;
3453 flags = fde->fde_flags;
3454 if (__predict_false(fp == NULL)) {
3455 if (seqc_consistent(fd_seqc(fdt, fd), seq))
3456 return (EBADF);
3457 fdt = atomic_load_ptr(&fdp->fd_files);
3458 continue;
3459 }
3460 error = cap_check_inline(&haverights, needrightsp);
3461 if (__predict_false(error != 0)) {
3462 if (seqc_consistent(fd_seqc(fdt, fd), seq))
3463 return (error);
3464 fdt = atomic_load_ptr(&fdp->fd_files);
3465 continue;
3466 }
3467 if (__predict_false(!refcount_acquire_if_not_zero(&fp->f_count))) {
3468 fdt = atomic_load_ptr(&fdp->fd_files);
3469 continue;
3470 }
3471 /*
3472 * Use an acquire barrier to force re-reading of fdt so it is
3473 * refreshed for verification.
3474 */
3475 atomic_thread_fence_acq();
3476 fdt = fdp->fd_files;
3477 if (seqc_consistent_no_fence(fd_seqc(fdt, fd), seq))
3478 break;
3479 fdrop(fp, td);
3480 }
3481 *fpp = fp;
3482 if (flagsp != NULL)
3483 *flagsp = flags;
3484 if (seqp != NULL)
3485 *seqp = seq;
3486 return (0);
3487 }
3488 #else
3489 static int
fget_unlocked_seq(struct thread * td,int fd,const cap_rights_t * needrightsp,uint8_t * flagsp,struct file ** fpp,seqc_t * seqp __unused)3490 fget_unlocked_seq(struct thread *td, int fd, const cap_rights_t *needrightsp,
3491 uint8_t *flagsp, struct file **fpp, seqc_t *seqp __unused)
3492 {
3493 struct filedesc *fdp;
3494 const struct fdescenttbl *fdt;
3495 struct file *fp;
3496 uint8_t flags;
3497
3498 fdp = td->td_proc->p_fd;
3499 fdt = fdp->fd_files;
3500 if (__predict_false((u_int)fd >= fdt->fdt_nfiles))
3501 return (EBADF);
3502
3503 for (;;) {
3504 fp = fdt->fdt_ofiles[fd].fde_file;
3505 flags = fdt->fdt_ofiles[fd].fde_flags;
3506 if (__predict_false(fp == NULL))
3507 return (EBADF);
3508 if (__predict_false(!refcount_acquire_if_not_zero(&fp->f_count))) {
3509 fdt = atomic_load_ptr(&fdp->fd_files);
3510 continue;
3511 }
3512 /*
3513 * Use an acquire barrier to force re-reading of fdt so it is
3514 * refreshed for verification.
3515 */
3516 atomic_thread_fence_acq();
3517 fdt = fdp->fd_files;
3518 if (__predict_true(fp == fdt->fdt_ofiles[fd].fde_file))
3519 break;
3520 fdrop(fp, td);
3521 }
3522 if (flagsp != NULL)
3523 *flagsp = flags;
3524 *fpp = fp;
3525 return (0);
3526 }
3527 #endif
3528
3529 /*
3530 * See the comments in fget_unlocked_seq for an explanation of how this works.
3531 *
3532 * This is a simplified variant which bails out to the aforementioned routine
3533 * if anything goes wrong. In practice this only happens when userspace is
3534 * racing with itself.
3535 */
3536 int
fget_unlocked_flags(struct thread * td,int fd,const cap_rights_t * needrightsp,uint8_t * flagsp,struct file ** fpp)3537 fget_unlocked_flags(struct thread *td, int fd, const cap_rights_t *needrightsp,
3538 uint8_t *flagsp, struct file **fpp)
3539 {
3540 struct filedesc *fdp;
3541 #ifdef CAPABILITIES
3542 const struct filedescent *fde;
3543 #endif
3544 const struct fdescenttbl *fdt;
3545 struct file *fp;
3546 #ifdef CAPABILITIES
3547 seqc_t seq;
3548 const cap_rights_t *haverights;
3549 #endif
3550 uint8_t flags;
3551
3552 fdp = td->td_proc->p_fd;
3553 fdt = fdp->fd_files;
3554 if (__predict_false((u_int)fd >= fdt->fdt_nfiles)) {
3555 *fpp = NULL;
3556 return (EBADF);
3557 }
3558 #ifdef CAPABILITIES
3559 seq = seqc_read_notmodify(fd_seqc(fdt, fd));
3560 fde = &fdt->fdt_ofiles[fd];
3561 haverights = cap_rights_fde_inline(fde);
3562 fp = fde->fde_file;
3563 flags = fde->fde_flags;
3564 #else
3565 fp = fdt->fdt_ofiles[fd].fde_file;
3566 flags = fdt->fdt_ofiles[fd].fde_flags;
3567 #endif
3568 if (__predict_false(fp == NULL))
3569 goto out_fallback;
3570 #ifdef CAPABILITIES
3571 if (__predict_false(cap_check_inline_transient(haverights, needrightsp)))
3572 goto out_fallback;
3573 #endif
3574 if (__predict_false(!refcount_acquire_if_not_zero(&fp->f_count)))
3575 goto out_fallback;
3576
3577 /*
3578 * Use an acquire barrier to force re-reading of fdt so it is
3579 * refreshed for verification.
3580 */
3581 atomic_thread_fence_acq();
3582 fdt = fdp->fd_files;
3583 #ifdef CAPABILITIES
3584 if (__predict_false(!seqc_consistent_no_fence(fd_seqc(fdt, fd), seq)))
3585 #else
3586 if (__predict_false(fp != fdt->fdt_ofiles[fd].fde_file))
3587 #endif
3588 goto out_fdrop;
3589 *fpp = fp;
3590 if (flagsp != NULL)
3591 *flagsp = flags;
3592 return (0);
3593 out_fdrop:
3594 fdrop(fp, td);
3595 out_fallback:
3596 *fpp = NULL;
3597 return (fget_unlocked_seq(td, fd, needrightsp, flagsp, fpp, NULL));
3598 }
3599
3600 int
fget_unlocked(struct thread * td,int fd,const cap_rights_t * needrightsp,struct file ** fpp)3601 fget_unlocked(struct thread *td, int fd, const cap_rights_t *needrightsp,
3602 struct file **fpp)
3603 {
3604 return (fget_unlocked_flags(td, fd, needrightsp, NULL, fpp));
3605 }
3606
3607 /*
3608 * Translate fd -> file when the caller guarantees the file descriptor table
3609 * can't be changed by others.
3610 *
3611 * Note this does not mean the file object itself is only visible to the caller,
3612 * merely that it wont disappear without having to be referenced.
3613 *
3614 * Must be paired with fput_only_user.
3615 */
3616 #ifdef CAPABILITIES
3617 int
fget_only_user(struct filedesc * fdp,int fd,const cap_rights_t * needrightsp,struct file ** fpp)3618 fget_only_user(struct filedesc *fdp, int fd, const cap_rights_t *needrightsp,
3619 struct file **fpp)
3620 {
3621 const struct filedescent *fde;
3622 const struct fdescenttbl *fdt;
3623 const cap_rights_t *haverights;
3624 struct file *fp;
3625 int error;
3626
3627 MPASS(FILEDESC_IS_ONLY_USER(fdp));
3628
3629 *fpp = NULL;
3630 if (__predict_false(fd >= fdp->fd_nfiles))
3631 return (EBADF);
3632
3633 fdt = fdp->fd_files;
3634 fde = &fdt->fdt_ofiles[fd];
3635 fp = fde->fde_file;
3636 if (__predict_false(fp == NULL))
3637 return (EBADF);
3638 MPASS(refcount_load(&fp->f_count) > 0);
3639 haverights = cap_rights_fde_inline(fde);
3640 error = cap_check_inline(haverights, needrightsp);
3641 if (__predict_false(error != 0))
3642 return (error);
3643 *fpp = fp;
3644 return (0);
3645 }
3646 #else
3647 int
fget_only_user(struct filedesc * fdp,int fd,const cap_rights_t * needrightsp,struct file ** fpp)3648 fget_only_user(struct filedesc *fdp, int fd, const cap_rights_t *needrightsp,
3649 struct file **fpp)
3650 {
3651 struct file *fp;
3652
3653 MPASS(FILEDESC_IS_ONLY_USER(fdp));
3654
3655 *fpp = NULL;
3656 if (__predict_false(fd >= fdp->fd_nfiles))
3657 return (EBADF);
3658
3659 fp = fdp->fd_ofiles[fd].fde_file;
3660 if (__predict_false(fp == NULL))
3661 return (EBADF);
3662
3663 MPASS(refcount_load(&fp->f_count) > 0);
3664 *fpp = fp;
3665 return (0);
3666 }
3667 #endif
3668
3669 /*
3670 * Extract the file pointer associated with the specified descriptor for the
3671 * current user process.
3672 *
3673 * If the descriptor doesn't exist or doesn't match 'flags', EBADF is
3674 * returned.
3675 *
3676 * File's rights will be checked against the capability rights mask.
3677 *
3678 * If an error occurred the non-zero error is returned and *fpp is set to
3679 * NULL. Otherwise *fpp is held and set and zero is returned. Caller is
3680 * responsible for fdrop().
3681 */
3682 static __inline int
_fget(struct thread * td,int fd,struct file ** fpp,int flags,const cap_rights_t * needrightsp)3683 _fget(struct thread *td, int fd, struct file **fpp, int flags,
3684 const cap_rights_t *needrightsp)
3685 {
3686 struct file *fp;
3687 int error;
3688
3689 *fpp = NULL;
3690 error = fget_unlocked(td, fd, needrightsp, &fp);
3691 if (__predict_false(error != 0))
3692 return (error);
3693 if (__predict_false(fp->f_ops == &badfileops)) {
3694 fdrop(fp, td);
3695 return (EBADF);
3696 }
3697
3698 /*
3699 * FREAD and FWRITE failure return EBADF as per POSIX.
3700 */
3701 error = 0;
3702 switch (flags) {
3703 case FREAD:
3704 case FWRITE:
3705 if ((fp->f_flag & flags) == 0)
3706 error = EBADF;
3707 break;
3708 case FEXEC:
3709 if (fp->f_ops != &path_fileops &&
3710 ((fp->f_flag & (FREAD | FEXEC)) == 0 ||
3711 (fp->f_flag & FWRITE) != 0))
3712 error = EBADF;
3713 break;
3714 case 0:
3715 break;
3716 default:
3717 KASSERT(0, ("wrong flags"));
3718 }
3719
3720 if (error != 0) {
3721 fdrop(fp, td);
3722 return (error);
3723 }
3724
3725 *fpp = fp;
3726 return (0);
3727 }
3728
3729 int
fget(struct thread * td,int fd,const cap_rights_t * rightsp,struct file ** fpp)3730 fget(struct thread *td, int fd, const cap_rights_t *rightsp, struct file **fpp)
3731 {
3732
3733 return (_fget(td, fd, fpp, 0, rightsp));
3734 }
3735
3736 int
fget_mmap(struct thread * td,int fd,const cap_rights_t * rightsp,vm_prot_t * maxprotp,struct file ** fpp)3737 fget_mmap(struct thread *td, int fd, const cap_rights_t *rightsp,
3738 vm_prot_t *maxprotp, struct file **fpp)
3739 {
3740 int error;
3741 #ifndef CAPABILITIES
3742 error = _fget(td, fd, fpp, 0, rightsp);
3743 if (maxprotp != NULL)
3744 *maxprotp = VM_PROT_ALL;
3745 return (error);
3746 #else
3747 cap_rights_t fdrights;
3748 struct filedesc *fdp;
3749 struct file *fp;
3750 seqc_t seq;
3751
3752 *fpp = NULL;
3753 fdp = td->td_proc->p_fd;
3754 MPASS(cap_rights_is_set(rightsp, CAP_MMAP));
3755 for (;;) {
3756 error = fget_unlocked_seq(td, fd, rightsp, NULL, &fp, &seq);
3757 if (__predict_false(error != 0))
3758 return (error);
3759 if (__predict_false(fp->f_ops == &badfileops)) {
3760 fdrop(fp, td);
3761 return (EBADF);
3762 }
3763 if (maxprotp != NULL)
3764 fdrights = *cap_rights(fdp, fd);
3765 if (!fd_modified(fdp, fd, seq))
3766 break;
3767 fdrop(fp, td);
3768 }
3769
3770 /*
3771 * If requested, convert capability rights to access flags.
3772 */
3773 if (maxprotp != NULL)
3774 *maxprotp = cap_rights_to_vmprot(&fdrights);
3775 *fpp = fp;
3776 return (0);
3777 #endif
3778 }
3779
3780 int
fget_read(struct thread * td,int fd,const cap_rights_t * rightsp,struct file ** fpp)3781 fget_read(struct thread *td, int fd, const cap_rights_t *rightsp,
3782 struct file **fpp)
3783 {
3784
3785 return (_fget(td, fd, fpp, FREAD, rightsp));
3786 }
3787
3788 int
fget_write(struct thread * td,int fd,const cap_rights_t * rightsp,struct file ** fpp)3789 fget_write(struct thread *td, int fd, const cap_rights_t *rightsp,
3790 struct file **fpp)
3791 {
3792
3793 return (_fget(td, fd, fpp, FWRITE, rightsp));
3794 }
3795
3796 int
fget_fcntl(struct thread * td,int fd,const cap_rights_t * rightsp,int needfcntl,struct file ** fpp)3797 fget_fcntl(struct thread *td, int fd, const cap_rights_t *rightsp,
3798 int needfcntl, struct file **fpp)
3799 {
3800 #ifndef CAPABILITIES
3801 return (fget_unlocked(td, fd, rightsp, fpp));
3802 #else
3803 struct filedesc *fdp = td->td_proc->p_fd;
3804 struct file *fp;
3805 int error;
3806 seqc_t seq;
3807
3808 *fpp = NULL;
3809 MPASS(cap_rights_is_set(rightsp, CAP_FCNTL));
3810 for (;;) {
3811 error = fget_unlocked_seq(td, fd, rightsp, NULL, &fp, &seq);
3812 if (error != 0)
3813 return (error);
3814 error = cap_fcntl_check(fdp, fd, needfcntl);
3815 if (!fd_modified(fdp, fd, seq))
3816 break;
3817 fdrop(fp, td);
3818 }
3819 if (error != 0) {
3820 fdrop(fp, td);
3821 return (error);
3822 }
3823 *fpp = fp;
3824 return (0);
3825 #endif
3826 }
3827
3828 /*
3829 * Like fget() but loads the underlying vnode, or returns an error if the
3830 * descriptor does not represent a vnode. Note that pipes use vnodes but
3831 * never have VM objects. The returned vnode will be vref()'d.
3832 *
3833 * XXX: what about the unused flags ?
3834 */
3835 static __inline int
_fgetvp(struct thread * td,int fd,int flags,const cap_rights_t * needrightsp,struct vnode ** vpp)3836 _fgetvp(struct thread *td, int fd, int flags, const cap_rights_t *needrightsp,
3837 struct vnode **vpp)
3838 {
3839 struct file *fp;
3840 int error;
3841
3842 *vpp = NULL;
3843 error = _fget(td, fd, &fp, flags, needrightsp);
3844 if (error != 0)
3845 return (error);
3846 if (fp->f_vnode == NULL) {
3847 error = EINVAL;
3848 } else {
3849 *vpp = fp->f_vnode;
3850 vrefact(*vpp);
3851 }
3852 fdrop(fp, td);
3853
3854 return (error);
3855 }
3856
3857 int
fgetvp(struct thread * td,int fd,const cap_rights_t * rightsp,struct vnode ** vpp)3858 fgetvp(struct thread *td, int fd, const cap_rights_t *rightsp,
3859 struct vnode **vpp)
3860 {
3861
3862 return (_fgetvp(td, fd, 0, rightsp, vpp));
3863 }
3864
3865 int
fgetvp_rights(struct thread * td,int fd,const cap_rights_t * needrightsp,struct filecaps * havecaps,struct vnode ** vpp)3866 fgetvp_rights(struct thread *td, int fd, const cap_rights_t *needrightsp,
3867 struct filecaps *havecaps, struct vnode **vpp)
3868 {
3869 struct filecaps caps;
3870 struct file *fp;
3871 int error;
3872
3873 error = fget_cap(td, fd, needrightsp, NULL, &fp, &caps);
3874 if (error != 0)
3875 return (error);
3876 if (fp->f_ops == &badfileops) {
3877 error = EBADF;
3878 goto out;
3879 }
3880 if (fp->f_vnode == NULL) {
3881 error = EINVAL;
3882 goto out;
3883 }
3884
3885 *havecaps = caps;
3886 *vpp = fp->f_vnode;
3887 vrefact(*vpp);
3888 fdrop(fp, td);
3889
3890 return (0);
3891 out:
3892 filecaps_free(&caps);
3893 fdrop(fp, td);
3894 return (error);
3895 }
3896
3897 int
fgetvp_read(struct thread * td,int fd,const cap_rights_t * rightsp,struct vnode ** vpp)3898 fgetvp_read(struct thread *td, int fd, const cap_rights_t *rightsp,
3899 struct vnode **vpp)
3900 {
3901
3902 return (_fgetvp(td, fd, FREAD, rightsp, vpp));
3903 }
3904
3905 int
fgetvp_exec(struct thread * td,int fd,const cap_rights_t * rightsp,struct vnode ** vpp)3906 fgetvp_exec(struct thread *td, int fd, const cap_rights_t *rightsp,
3907 struct vnode **vpp)
3908 {
3909
3910 return (_fgetvp(td, fd, FEXEC, rightsp, vpp));
3911 }
3912
3913 #ifdef notyet
3914 int
fgetvp_write(struct thread * td,int fd,const cap_rights_t * rightsp,struct vnode ** vpp)3915 fgetvp_write(struct thread *td, int fd, const cap_rights_t *rightsp,
3916 struct vnode **vpp)
3917 {
3918
3919 return (_fgetvp(td, fd, FWRITE, rightsp, vpp));
3920 }
3921 #endif
3922
3923 /*
3924 * Handle the last reference to a file being closed.
3925 *
3926 * Without the noinline attribute clang keeps inlining the func thorough this
3927 * file when fdrop is used.
3928 */
3929 int __noinline
_fdrop(struct file * fp,struct thread * td)3930 _fdrop(struct file *fp, struct thread *td)
3931 {
3932 int error;
3933
3934 KASSERT(refcount_load(&fp->f_count) == 0,
3935 ("fdrop: fp %p count %d", fp, refcount_load(&fp->f_count)));
3936
3937 error = fo_close(fp, td);
3938 atomic_subtract_int(&openfiles, 1);
3939 crfree(fp->f_cred);
3940 free(fp->f_advice, M_FADVISE);
3941 uma_zfree(file_zone, fp);
3942
3943 return (error);
3944 }
3945
3946 /*
3947 * Apply an advisory lock on a file descriptor.
3948 *
3949 * Just attempt to get a record lock of the requested type on the entire file
3950 * (l_whence = SEEK_SET, l_start = 0, l_len = 0).
3951 */
3952 #ifndef _SYS_SYSPROTO_H_
3953 struct flock_args {
3954 int fd;
3955 int how;
3956 };
3957 #endif
3958 /* ARGSUSED */
3959 int
sys_flock(struct thread * td,struct flock_args * uap)3960 sys_flock(struct thread *td, struct flock_args *uap)
3961 {
3962 struct file *fp;
3963 struct vnode *vp;
3964 struct flock lf;
3965 int error;
3966
3967 error = fget(td, uap->fd, &cap_flock_rights, &fp);
3968 if (error != 0)
3969 return (error);
3970 error = EOPNOTSUPP;
3971 if (fp->f_type != DTYPE_VNODE && fp->f_type != DTYPE_FIFO) {
3972 goto done;
3973 }
3974 if (fp->f_ops == &path_fileops) {
3975 goto done;
3976 }
3977
3978 error = 0;
3979 vp = fp->f_vnode;
3980 lf.l_whence = SEEK_SET;
3981 lf.l_start = 0;
3982 lf.l_len = 0;
3983 if (uap->how & LOCK_UN) {
3984 lf.l_type = F_UNLCK;
3985 atomic_clear_int(&fp->f_flag, FHASLOCK);
3986 error = VOP_ADVLOCK(vp, (caddr_t)fp, F_UNLCK, &lf, F_FLOCK);
3987 goto done;
3988 }
3989 if (uap->how & LOCK_EX)
3990 lf.l_type = F_WRLCK;
3991 else if (uap->how & LOCK_SH)
3992 lf.l_type = F_RDLCK;
3993 else {
3994 error = EBADF;
3995 goto done;
3996 }
3997 atomic_set_int(&fp->f_flag, FHASLOCK);
3998 error = VOP_ADVLOCK(vp, (caddr_t)fp, F_SETLK, &lf,
3999 (uap->how & LOCK_NB) ? F_FLOCK : F_FLOCK | F_WAIT);
4000 done:
4001 fdrop(fp, td);
4002 return (error);
4003 }
4004 /*
4005 * Duplicate the specified descriptor to a free descriptor.
4006 */
4007 int
dupfdopen(struct thread * td,struct filedesc * fdp,int dfd,int mode,int openerror,int * indxp)4008 dupfdopen(struct thread *td, struct filedesc *fdp, int dfd, int mode,
4009 int openerror, int *indxp)
4010 {
4011 struct filedescent *newfde, *oldfde;
4012 struct file *fp;
4013 u_long *ioctls;
4014 int error, indx;
4015
4016 KASSERT(openerror == ENODEV || openerror == ENXIO,
4017 ("unexpected error %d in %s", openerror, __func__));
4018
4019 /*
4020 * If the to-be-dup'd fd number is greater than the allowed number
4021 * of file descriptors, or the fd to be dup'd has already been
4022 * closed, then reject.
4023 */
4024 FILEDESC_XLOCK(fdp);
4025 if ((fp = fget_noref(fdp, dfd)) == NULL) {
4026 FILEDESC_XUNLOCK(fdp);
4027 return (EBADF);
4028 }
4029
4030 error = fdalloc(td, 0, &indx);
4031 if (error != 0) {
4032 FILEDESC_XUNLOCK(fdp);
4033 return (error);
4034 }
4035
4036 /*
4037 * There are two cases of interest here.
4038 *
4039 * For ENODEV simply dup (dfd) to file descriptor (indx) and return.
4040 *
4041 * For ENXIO steal away the file structure from (dfd) and store it in
4042 * (indx). (dfd) is effectively closed by this operation.
4043 */
4044 switch (openerror) {
4045 case ENODEV:
4046 /*
4047 * Check that the mode the file is being opened for is a
4048 * subset of the mode of the existing descriptor.
4049 */
4050 if (((mode & (FREAD|FWRITE)) | fp->f_flag) != fp->f_flag) {
4051 fdunused(fdp, indx);
4052 FILEDESC_XUNLOCK(fdp);
4053 return (EACCES);
4054 }
4055 if (!fhold(fp)) {
4056 fdunused(fdp, indx);
4057 FILEDESC_XUNLOCK(fdp);
4058 return (EBADF);
4059 }
4060 newfde = &fdp->fd_ofiles[indx];
4061 oldfde = &fdp->fd_ofiles[dfd];
4062 ioctls = filecaps_copy_prep(&oldfde->fde_caps);
4063 #ifdef CAPABILITIES
4064 seqc_write_begin(&newfde->fde_seqc);
4065 #endif
4066 fde_copy(oldfde, newfde);
4067 filecaps_copy_finish(&oldfde->fde_caps, &newfde->fde_caps,
4068 ioctls);
4069 #ifdef CAPABILITIES
4070 seqc_write_end(&newfde->fde_seqc);
4071 #endif
4072 break;
4073 case ENXIO:
4074 /*
4075 * Steal away the file pointer from dfd and stuff it into indx.
4076 */
4077 newfde = &fdp->fd_ofiles[indx];
4078 oldfde = &fdp->fd_ofiles[dfd];
4079 #ifdef CAPABILITIES
4080 seqc_write_begin(&oldfde->fde_seqc);
4081 seqc_write_begin(&newfde->fde_seqc);
4082 #endif
4083 fde_copy(oldfde, newfde);
4084 oldfde->fde_file = NULL;
4085 fdunused(fdp, dfd);
4086 #ifdef CAPABILITIES
4087 seqc_write_end(&newfde->fde_seqc);
4088 seqc_write_end(&oldfde->fde_seqc);
4089 #endif
4090 break;
4091 }
4092 FILEDESC_XUNLOCK(fdp);
4093 *indxp = indx;
4094 return (0);
4095 }
4096
4097 /*
4098 * This sysctl determines if we will allow a process to chroot(2) if it
4099 * has a directory open:
4100 * 0: disallowed for all processes.
4101 * 1: allowed for processes that were not already chroot(2)'ed.
4102 * 2: allowed for all processes.
4103 */
4104
4105 static int chroot_allow_open_directories = 1;
4106
4107 SYSCTL_INT(_kern, OID_AUTO, chroot_allow_open_directories, CTLFLAG_RW,
4108 &chroot_allow_open_directories, 0,
4109 "Allow a process to chroot(2) if it has a directory open");
4110
4111 /*
4112 * Helper function for raised chroot(2) security function: Refuse if
4113 * any filedescriptors are open directories.
4114 */
4115 static int
chroot_refuse_vdir_fds(struct filedesc * fdp)4116 chroot_refuse_vdir_fds(struct filedesc *fdp)
4117 {
4118 struct vnode *vp;
4119 struct file *fp;
4120 int i;
4121
4122 FILEDESC_LOCK_ASSERT(fdp);
4123
4124 FILEDESC_FOREACH_FP(fdp, i, fp) {
4125 if (fp->f_type == DTYPE_VNODE) {
4126 vp = fp->f_vnode;
4127 if (vp->v_type == VDIR)
4128 return (EPERM);
4129 }
4130 }
4131 return (0);
4132 }
4133
4134 static void
pwd_fill(struct pwd * oldpwd,struct pwd * newpwd)4135 pwd_fill(struct pwd *oldpwd, struct pwd *newpwd)
4136 {
4137
4138 if (newpwd->pwd_cdir == NULL && oldpwd->pwd_cdir != NULL) {
4139 vrefact(oldpwd->pwd_cdir);
4140 newpwd->pwd_cdir = oldpwd->pwd_cdir;
4141 }
4142
4143 if (newpwd->pwd_rdir == NULL && oldpwd->pwd_rdir != NULL) {
4144 vrefact(oldpwd->pwd_rdir);
4145 newpwd->pwd_rdir = oldpwd->pwd_rdir;
4146 }
4147
4148 if (newpwd->pwd_jdir == NULL && oldpwd->pwd_jdir != NULL) {
4149 vrefact(oldpwd->pwd_jdir);
4150 newpwd->pwd_jdir = oldpwd->pwd_jdir;
4151 }
4152
4153 if (newpwd->pwd_adir == NULL && oldpwd->pwd_adir != NULL) {
4154 vrefact(oldpwd->pwd_adir);
4155 newpwd->pwd_adir = oldpwd->pwd_adir;
4156 }
4157 }
4158
4159 struct pwd *
pwd_hold_pwddesc(struct pwddesc * pdp)4160 pwd_hold_pwddesc(struct pwddesc *pdp)
4161 {
4162 struct pwd *pwd;
4163
4164 PWDDESC_ASSERT_XLOCKED(pdp);
4165 pwd = PWDDESC_XLOCKED_LOAD_PWD(pdp);
4166 if (pwd != NULL)
4167 refcount_acquire(&pwd->pwd_refcount);
4168 return (pwd);
4169 }
4170
4171 bool
pwd_hold_smr(struct pwd * pwd)4172 pwd_hold_smr(struct pwd *pwd)
4173 {
4174
4175 MPASS(pwd != NULL);
4176 if (__predict_true(refcount_acquire_if_not_zero(&pwd->pwd_refcount))) {
4177 return (true);
4178 }
4179 return (false);
4180 }
4181
4182 struct pwd *
pwd_hold(struct thread * td)4183 pwd_hold(struct thread *td)
4184 {
4185 struct pwddesc *pdp;
4186 struct pwd *pwd;
4187
4188 pdp = td->td_proc->p_pd;
4189
4190 vfs_smr_enter();
4191 pwd = vfs_smr_entered_load(&pdp->pd_pwd);
4192 if (pwd_hold_smr(pwd)) {
4193 vfs_smr_exit();
4194 return (pwd);
4195 }
4196 vfs_smr_exit();
4197 PWDDESC_XLOCK(pdp);
4198 pwd = pwd_hold_pwddesc(pdp);
4199 MPASS(pwd != NULL);
4200 PWDDESC_XUNLOCK(pdp);
4201 return (pwd);
4202 }
4203
4204 struct pwd *
pwd_hold_proc(struct proc * p)4205 pwd_hold_proc(struct proc *p)
4206 {
4207 struct pwddesc *pdp;
4208 struct pwd *pwd;
4209
4210 PROC_ASSERT_HELD(p);
4211 PROC_LOCK(p);
4212 pdp = pdhold(p);
4213 MPASS(pdp != NULL);
4214 PROC_UNLOCK(p);
4215
4216 PWDDESC_XLOCK(pdp);
4217 pwd = pwd_hold_pwddesc(pdp);
4218 MPASS(pwd != NULL);
4219 PWDDESC_XUNLOCK(pdp);
4220 pddrop(pdp);
4221 return (pwd);
4222 }
4223
4224 static struct pwd *
pwd_alloc(void)4225 pwd_alloc(void)
4226 {
4227 struct pwd *pwd;
4228
4229 pwd = uma_zalloc_smr(pwd_zone, M_WAITOK);
4230 bzero(pwd, sizeof(*pwd));
4231 refcount_init(&pwd->pwd_refcount, 1);
4232 return (pwd);
4233 }
4234
4235 void
pwd_drop(struct pwd * pwd)4236 pwd_drop(struct pwd *pwd)
4237 {
4238
4239 if (!refcount_release(&pwd->pwd_refcount))
4240 return;
4241
4242 if (pwd->pwd_cdir != NULL)
4243 vrele(pwd->pwd_cdir);
4244 if (pwd->pwd_rdir != NULL)
4245 vrele(pwd->pwd_rdir);
4246 if (pwd->pwd_jdir != NULL)
4247 vrele(pwd->pwd_jdir);
4248 if (pwd->pwd_adir != NULL)
4249 vrele(pwd->pwd_adir);
4250 uma_zfree_smr(pwd_zone, pwd);
4251 }
4252
4253 /*
4254 * The caller is responsible for invoking priv_check() and
4255 * mac_vnode_check_chroot() to authorize this operation.
4256 */
4257 int
pwd_chroot(struct thread * td,struct vnode * vp)4258 pwd_chroot(struct thread *td, struct vnode *vp)
4259 {
4260 struct pwddesc *pdp;
4261 struct filedesc *fdp;
4262 struct pwd *newpwd, *oldpwd;
4263 int error;
4264
4265 fdp = td->td_proc->p_fd;
4266 pdp = td->td_proc->p_pd;
4267 newpwd = pwd_alloc();
4268 FILEDESC_SLOCK(fdp);
4269 PWDDESC_XLOCK(pdp);
4270 oldpwd = PWDDESC_XLOCKED_LOAD_PWD(pdp);
4271 if (chroot_allow_open_directories == 0 ||
4272 (chroot_allow_open_directories == 1 &&
4273 oldpwd->pwd_rdir != rootvnode)) {
4274 error = chroot_refuse_vdir_fds(fdp);
4275 FILEDESC_SUNLOCK(fdp);
4276 if (error != 0) {
4277 PWDDESC_XUNLOCK(pdp);
4278 pwd_drop(newpwd);
4279 return (error);
4280 }
4281 } else {
4282 FILEDESC_SUNLOCK(fdp);
4283 }
4284
4285 vrefact(vp);
4286 newpwd->pwd_rdir = vp;
4287 vrefact(vp);
4288 newpwd->pwd_adir = vp;
4289 if (oldpwd->pwd_jdir == NULL) {
4290 vrefact(vp);
4291 newpwd->pwd_jdir = vp;
4292 }
4293 pwd_fill(oldpwd, newpwd);
4294 pwd_set(pdp, newpwd);
4295 PWDDESC_XUNLOCK(pdp);
4296 pwd_drop(oldpwd);
4297 return (0);
4298 }
4299
4300 void
pwd_chdir(struct thread * td,struct vnode * vp)4301 pwd_chdir(struct thread *td, struct vnode *vp)
4302 {
4303 struct pwddesc *pdp;
4304 struct pwd *newpwd, *oldpwd;
4305
4306 VNPASS(vp->v_usecount > 0, vp);
4307
4308 newpwd = pwd_alloc();
4309 pdp = td->td_proc->p_pd;
4310 PWDDESC_XLOCK(pdp);
4311 oldpwd = PWDDESC_XLOCKED_LOAD_PWD(pdp);
4312 newpwd->pwd_cdir = vp;
4313 pwd_fill(oldpwd, newpwd);
4314 pwd_set(pdp, newpwd);
4315 PWDDESC_XUNLOCK(pdp);
4316 pwd_drop(oldpwd);
4317 }
4318
4319 /*
4320 * Process is transitioning to/from a non-native ABI.
4321 */
4322 void
pwd_altroot(struct thread * td,struct vnode * altroot_vp)4323 pwd_altroot(struct thread *td, struct vnode *altroot_vp)
4324 {
4325 struct pwddesc *pdp;
4326 struct pwd *newpwd, *oldpwd;
4327
4328 newpwd = pwd_alloc();
4329 pdp = td->td_proc->p_pd;
4330 PWDDESC_XLOCK(pdp);
4331 oldpwd = PWDDESC_XLOCKED_LOAD_PWD(pdp);
4332 if (altroot_vp != NULL) {
4333 /*
4334 * Native process to a non-native ABI.
4335 */
4336
4337 vrefact(altroot_vp);
4338 newpwd->pwd_adir = altroot_vp;
4339 } else {
4340 /*
4341 * Non-native process to the native ABI.
4342 */
4343
4344 vrefact(oldpwd->pwd_rdir);
4345 newpwd->pwd_adir = oldpwd->pwd_rdir;
4346 }
4347 pwd_fill(oldpwd, newpwd);
4348 pwd_set(pdp, newpwd);
4349 PWDDESC_XUNLOCK(pdp);
4350 pwd_drop(oldpwd);
4351 }
4352
4353 /*
4354 * jail_attach(2) changes both root and working directories.
4355 */
4356 int
pwd_chroot_chdir(struct thread * td,struct vnode * vp)4357 pwd_chroot_chdir(struct thread *td, struct vnode *vp)
4358 {
4359 struct pwddesc *pdp;
4360 struct filedesc *fdp;
4361 struct pwd *newpwd, *oldpwd;
4362 int error;
4363
4364 fdp = td->td_proc->p_fd;
4365 pdp = td->td_proc->p_pd;
4366 newpwd = pwd_alloc();
4367 FILEDESC_SLOCK(fdp);
4368 PWDDESC_XLOCK(pdp);
4369 oldpwd = PWDDESC_XLOCKED_LOAD_PWD(pdp);
4370 error = chroot_refuse_vdir_fds(fdp);
4371 FILEDESC_SUNLOCK(fdp);
4372 if (error != 0) {
4373 PWDDESC_XUNLOCK(pdp);
4374 pwd_drop(newpwd);
4375 return (error);
4376 }
4377
4378 vrefact(vp);
4379 newpwd->pwd_rdir = vp;
4380 vrefact(vp);
4381 newpwd->pwd_cdir = vp;
4382 if (oldpwd->pwd_jdir == NULL) {
4383 vrefact(vp);
4384 newpwd->pwd_jdir = vp;
4385 }
4386 vrefact(vp);
4387 newpwd->pwd_adir = vp;
4388 pwd_fill(oldpwd, newpwd);
4389 pwd_set(pdp, newpwd);
4390 PWDDESC_XUNLOCK(pdp);
4391 pwd_drop(oldpwd);
4392 return (0);
4393 }
4394
4395 void
pwd_ensure_dirs(void)4396 pwd_ensure_dirs(void)
4397 {
4398 struct pwddesc *pdp;
4399 struct pwd *oldpwd, *newpwd;
4400
4401 pdp = curproc->p_pd;
4402 PWDDESC_XLOCK(pdp);
4403 oldpwd = PWDDESC_XLOCKED_LOAD_PWD(pdp);
4404 if (oldpwd->pwd_cdir != NULL && oldpwd->pwd_rdir != NULL &&
4405 oldpwd->pwd_adir != NULL) {
4406 PWDDESC_XUNLOCK(pdp);
4407 return;
4408 }
4409 PWDDESC_XUNLOCK(pdp);
4410
4411 newpwd = pwd_alloc();
4412 PWDDESC_XLOCK(pdp);
4413 oldpwd = PWDDESC_XLOCKED_LOAD_PWD(pdp);
4414 pwd_fill(oldpwd, newpwd);
4415 if (newpwd->pwd_cdir == NULL) {
4416 vrefact(rootvnode);
4417 newpwd->pwd_cdir = rootvnode;
4418 }
4419 if (newpwd->pwd_rdir == NULL) {
4420 vrefact(rootvnode);
4421 newpwd->pwd_rdir = rootvnode;
4422 }
4423 if (newpwd->pwd_adir == NULL) {
4424 vrefact(rootvnode);
4425 newpwd->pwd_adir = rootvnode;
4426 }
4427 pwd_set(pdp, newpwd);
4428 PWDDESC_XUNLOCK(pdp);
4429 pwd_drop(oldpwd);
4430 }
4431
4432 void
pwd_set_rootvnode(void)4433 pwd_set_rootvnode(void)
4434 {
4435 struct pwddesc *pdp;
4436 struct pwd *oldpwd, *newpwd;
4437
4438 pdp = curproc->p_pd;
4439
4440 newpwd = pwd_alloc();
4441 PWDDESC_XLOCK(pdp);
4442 oldpwd = PWDDESC_XLOCKED_LOAD_PWD(pdp);
4443 vrefact(rootvnode);
4444 newpwd->pwd_cdir = rootvnode;
4445 vrefact(rootvnode);
4446 newpwd->pwd_rdir = rootvnode;
4447 vrefact(rootvnode);
4448 newpwd->pwd_adir = rootvnode;
4449 pwd_fill(oldpwd, newpwd);
4450 pwd_set(pdp, newpwd);
4451 PWDDESC_XUNLOCK(pdp);
4452 pwd_drop(oldpwd);
4453 }
4454
4455 /*
4456 * Scan all active processes and prisons to see if any of them have a current
4457 * or root directory of `olddp'. If so, replace them with the new mount point.
4458 */
4459 void
mountcheckdirs(struct vnode * olddp,struct vnode * newdp)4460 mountcheckdirs(struct vnode *olddp, struct vnode *newdp)
4461 {
4462 struct pwddesc *pdp;
4463 struct pwd *newpwd, *oldpwd;
4464 struct prison *pr;
4465 struct proc *p;
4466 int nrele;
4467
4468 if (vrefcnt(olddp) == 1)
4469 return;
4470 nrele = 0;
4471 newpwd = pwd_alloc();
4472 sx_slock(&allproc_lock);
4473 FOREACH_PROC_IN_SYSTEM(p) {
4474 PROC_LOCK(p);
4475 pdp = pdhold(p);
4476 PROC_UNLOCK(p);
4477 if (pdp == NULL)
4478 continue;
4479 PWDDESC_XLOCK(pdp);
4480 oldpwd = PWDDESC_XLOCKED_LOAD_PWD(pdp);
4481 if (oldpwd == NULL ||
4482 (oldpwd->pwd_cdir != olddp &&
4483 oldpwd->pwd_rdir != olddp &&
4484 oldpwd->pwd_jdir != olddp &&
4485 oldpwd->pwd_adir != olddp)) {
4486 PWDDESC_XUNLOCK(pdp);
4487 pddrop(pdp);
4488 continue;
4489 }
4490 if (oldpwd->pwd_cdir == olddp) {
4491 vrefact(newdp);
4492 newpwd->pwd_cdir = newdp;
4493 }
4494 if (oldpwd->pwd_rdir == olddp) {
4495 vrefact(newdp);
4496 newpwd->pwd_rdir = newdp;
4497 }
4498 if (oldpwd->pwd_jdir == olddp) {
4499 vrefact(newdp);
4500 newpwd->pwd_jdir = newdp;
4501 }
4502 if (oldpwd->pwd_adir == olddp) {
4503 vrefact(newdp);
4504 newpwd->pwd_adir = newdp;
4505 }
4506 pwd_fill(oldpwd, newpwd);
4507 pwd_set(pdp, newpwd);
4508 PWDDESC_XUNLOCK(pdp);
4509 pwd_drop(oldpwd);
4510 pddrop(pdp);
4511 newpwd = pwd_alloc();
4512 }
4513 sx_sunlock(&allproc_lock);
4514 pwd_drop(newpwd);
4515 if (rootvnode == olddp) {
4516 vrefact(newdp);
4517 rootvnode = newdp;
4518 nrele++;
4519 }
4520 mtx_lock(&prison0.pr_mtx);
4521 if (prison0.pr_root == olddp) {
4522 vrefact(newdp);
4523 prison0.pr_root = newdp;
4524 nrele++;
4525 }
4526 mtx_unlock(&prison0.pr_mtx);
4527 sx_slock(&allprison_lock);
4528 TAILQ_FOREACH(pr, &allprison, pr_list) {
4529 mtx_lock(&pr->pr_mtx);
4530 if (pr->pr_root == olddp) {
4531 vrefact(newdp);
4532 pr->pr_root = newdp;
4533 nrele++;
4534 }
4535 mtx_unlock(&pr->pr_mtx);
4536 }
4537 sx_sunlock(&allprison_lock);
4538 while (nrele--)
4539 vrele(olddp);
4540 }
4541
4542 int
descrip_check_write_mp(struct filedesc * fdp,struct mount * mp)4543 descrip_check_write_mp(struct filedesc *fdp, struct mount *mp)
4544 {
4545 struct file *fp;
4546 struct vnode *vp;
4547 int error, i;
4548
4549 error = 0;
4550 FILEDESC_SLOCK(fdp);
4551 FILEDESC_FOREACH_FP(fdp, i, fp) {
4552 if (fp->f_type != DTYPE_VNODE ||
4553 (atomic_load_int(&fp->f_flag) & FWRITE) == 0)
4554 continue;
4555 vp = fp->f_vnode;
4556 if (vp->v_mount == mp) {
4557 error = EDEADLK;
4558 break;
4559 }
4560 }
4561 FILEDESC_SUNLOCK(fdp);
4562 return (error);
4563 }
4564
4565 struct filedesc_to_leader *
filedesc_to_leader_alloc(struct filedesc_to_leader * old,struct filedesc * fdp,struct proc * leader)4566 filedesc_to_leader_alloc(struct filedesc_to_leader *old, struct filedesc *fdp,
4567 struct proc *leader)
4568 {
4569 struct filedesc_to_leader *fdtol;
4570
4571 fdtol = malloc(sizeof(struct filedesc_to_leader),
4572 M_FILEDESC_TO_LEADER, M_WAITOK);
4573 fdtol->fdl_refcount = 1;
4574 fdtol->fdl_holdcount = 0;
4575 fdtol->fdl_wakeup = 0;
4576 fdtol->fdl_leader = leader;
4577 if (old != NULL) {
4578 FILEDESC_XLOCK(fdp);
4579 fdtol->fdl_next = old->fdl_next;
4580 fdtol->fdl_prev = old;
4581 old->fdl_next = fdtol;
4582 fdtol->fdl_next->fdl_prev = fdtol;
4583 FILEDESC_XUNLOCK(fdp);
4584 } else {
4585 fdtol->fdl_next = fdtol;
4586 fdtol->fdl_prev = fdtol;
4587 }
4588 return (fdtol);
4589 }
4590
4591 struct filedesc_to_leader *
filedesc_to_leader_share(struct filedesc_to_leader * fdtol,struct filedesc * fdp)4592 filedesc_to_leader_share(struct filedesc_to_leader *fdtol, struct filedesc *fdp)
4593 {
4594 FILEDESC_XLOCK(fdp);
4595 fdtol->fdl_refcount++;
4596 FILEDESC_XUNLOCK(fdp);
4597 return (fdtol);
4598 }
4599
4600 static int
filedesc_nfiles(struct filedesc * fdp)4601 filedesc_nfiles(struct filedesc *fdp)
4602 {
4603 NDSLOTTYPE *map;
4604 int count, off, minoff;
4605
4606 if (fdp == NULL)
4607 return (0);
4608 count = 0;
4609 FILEDESC_SLOCK(fdp);
4610 map = fdp->fd_map;
4611 off = NDSLOT(fdp->fd_nfiles - 1);
4612 for (minoff = NDSLOT(0); off >= minoff; --off)
4613 count += bitcountl(map[off]);
4614 FILEDESC_SUNLOCK(fdp);
4615 return (count);
4616 }
4617
4618 int
proc_nfiles(struct proc * p)4619 proc_nfiles(struct proc *p)
4620 {
4621 struct filedesc *fdp;
4622 int res;
4623
4624 PROC_LOCK(p);
4625 fdp = fdhold(p);
4626 PROC_UNLOCK(p);
4627 res = filedesc_nfiles(fdp);
4628 fddrop(fdp);
4629 return (res);
4630 }
4631
4632 static int
sysctl_kern_proc_nfds(SYSCTL_HANDLER_ARGS)4633 sysctl_kern_proc_nfds(SYSCTL_HANDLER_ARGS)
4634 {
4635 u_int namelen;
4636 int count;
4637
4638 namelen = arg2;
4639 if (namelen != 1)
4640 return (EINVAL);
4641
4642 if (*(int *)arg1 != 0)
4643 return (EINVAL);
4644
4645 count = filedesc_nfiles(curproc->p_fd);
4646 return (SYSCTL_OUT(req, &count, sizeof(count)));
4647 }
4648
4649 static SYSCTL_NODE(_kern_proc, KERN_PROC_NFDS, nfds,
4650 CTLFLAG_RD|CTLFLAG_CAPRD|CTLFLAG_MPSAFE, sysctl_kern_proc_nfds,
4651 "Number of open file descriptors");
4652
4653 /*
4654 * Get file structures globally.
4655 */
4656 static int
sysctl_kern_file(SYSCTL_HANDLER_ARGS)4657 sysctl_kern_file(SYSCTL_HANDLER_ARGS)
4658 {
4659 struct xfile xf;
4660 struct filedesc *fdp;
4661 struct file *fp;
4662 struct proc *p;
4663 int error, n;
4664
4665 error = sysctl_wire_old_buffer(req, 0);
4666 if (error != 0)
4667 return (error);
4668 if (req->oldptr == NULL) {
4669 n = 0;
4670 sx_slock(&allproc_lock);
4671 FOREACH_PROC_IN_SYSTEM(p) {
4672 PROC_LOCK(p);
4673 if (p->p_state == PRS_NEW) {
4674 PROC_UNLOCK(p);
4675 continue;
4676 }
4677 fdp = fdhold(p);
4678 PROC_UNLOCK(p);
4679 if (fdp == NULL)
4680 continue;
4681 /* overestimates sparse tables. */
4682 n += fdp->fd_nfiles;
4683 fddrop(fdp);
4684 }
4685 sx_sunlock(&allproc_lock);
4686 return (SYSCTL_OUT(req, 0, n * sizeof(xf)));
4687 }
4688 error = 0;
4689 bzero(&xf, sizeof(xf));
4690 xf.xf_size = sizeof(xf);
4691 sx_slock(&allproc_lock);
4692 FOREACH_PROC_IN_SYSTEM(p) {
4693 PROC_LOCK(p);
4694 if (p->p_state == PRS_NEW) {
4695 PROC_UNLOCK(p);
4696 continue;
4697 }
4698 if (p_cansee(req->td, p) != 0) {
4699 PROC_UNLOCK(p);
4700 continue;
4701 }
4702 xf.xf_pid = p->p_pid;
4703 xf.xf_uid = p->p_ucred->cr_uid;
4704 fdp = fdhold(p);
4705 PROC_UNLOCK(p);
4706 if (fdp == NULL)
4707 continue;
4708 FILEDESC_SLOCK(fdp);
4709 if (refcount_load(&fdp->fd_refcnt) == 0)
4710 goto nextproc;
4711 FILEDESC_FOREACH_FP(fdp, n, fp) {
4712 xf.xf_fd = n;
4713 xf.xf_file = (uintptr_t)fp;
4714 xf.xf_data = (uintptr_t)fp->f_data;
4715 xf.xf_vnode = (uintptr_t)fp->f_vnode;
4716 xf.xf_type = (uintptr_t)fp->f_type;
4717 xf.xf_count = refcount_load(&fp->f_count);
4718 xf.xf_msgcount = 0;
4719 xf.xf_offset = foffset_get(fp);
4720 xf.xf_flag = fp->f_flag;
4721 error = SYSCTL_OUT(req, &xf, sizeof(xf));
4722
4723 /*
4724 * There is no need to re-check the fdtable refcount
4725 * here since the filedesc lock is not dropped in the
4726 * loop body.
4727 */
4728 if (error != 0)
4729 break;
4730 }
4731 nextproc:
4732 FILEDESC_SUNLOCK(fdp);
4733 fddrop(fdp);
4734 if (error)
4735 break;
4736 }
4737 sx_sunlock(&allproc_lock);
4738 return (error);
4739 }
4740
4741 SYSCTL_PROC(_kern, KERN_FILE, file, CTLTYPE_OPAQUE|CTLFLAG_RD|CTLFLAG_MPSAFE,
4742 0, 0, sysctl_kern_file, "S,xfile", "Entire file table");
4743
4744 #ifdef KINFO_FILE_SIZE
4745 CTASSERT(sizeof(struct kinfo_file) == KINFO_FILE_SIZE);
4746 #endif
4747
4748 static int
xlate_fflags(int fflags)4749 xlate_fflags(int fflags)
4750 {
4751 static const struct {
4752 int fflag;
4753 int kf_fflag;
4754 } fflags_table[] = {
4755 { FAPPEND, KF_FLAG_APPEND },
4756 { FASYNC, KF_FLAG_ASYNC },
4757 { FFSYNC, KF_FLAG_FSYNC },
4758 { FHASLOCK, KF_FLAG_HASLOCK },
4759 { FNONBLOCK, KF_FLAG_NONBLOCK },
4760 { FREAD, KF_FLAG_READ },
4761 { FWRITE, KF_FLAG_WRITE },
4762 { O_CREAT, KF_FLAG_CREAT },
4763 { O_DIRECT, KF_FLAG_DIRECT },
4764 { O_EXCL, KF_FLAG_EXCL },
4765 { O_EXEC, KF_FLAG_EXEC },
4766 { O_EXLOCK, KF_FLAG_EXLOCK },
4767 { O_NOFOLLOW, KF_FLAG_NOFOLLOW },
4768 { O_SHLOCK, KF_FLAG_SHLOCK },
4769 { O_TRUNC, KF_FLAG_TRUNC }
4770 };
4771 unsigned int i;
4772 int kflags;
4773
4774 kflags = 0;
4775 for (i = 0; i < nitems(fflags_table); i++)
4776 if (fflags & fflags_table[i].fflag)
4777 kflags |= fflags_table[i].kf_fflag;
4778 return (kflags);
4779 }
4780
4781 /* Trim unused data from kf_path by truncating the structure size. */
4782 void
pack_kinfo(struct kinfo_file * kif)4783 pack_kinfo(struct kinfo_file *kif)
4784 {
4785
4786 kif->kf_structsize = offsetof(struct kinfo_file, kf_path) +
4787 strlen(kif->kf_path) + 1;
4788 kif->kf_structsize = roundup(kif->kf_structsize, sizeof(uint64_t));
4789 }
4790
4791 static void
export_file_to_kinfo(struct file * fp,int fd,cap_rights_t * rightsp,struct kinfo_file * kif,struct filedesc * fdp,int flags)4792 export_file_to_kinfo(struct file *fp, int fd, cap_rights_t *rightsp,
4793 struct kinfo_file *kif, struct filedesc *fdp, int flags)
4794 {
4795 int error;
4796
4797 bzero(kif, sizeof(*kif));
4798
4799 /* Set a default type to allow for empty fill_kinfo() methods. */
4800 kif->kf_type = KF_TYPE_UNKNOWN;
4801 kif->kf_flags = xlate_fflags(fp->f_flag);
4802 if (rightsp != NULL)
4803 kif->kf_cap_rights = *rightsp;
4804 else
4805 cap_rights_init_zero(&kif->kf_cap_rights);
4806 kif->kf_fd = fd;
4807 kif->kf_ref_count = refcount_load(&fp->f_count);
4808 kif->kf_offset = foffset_get(fp);
4809
4810 /*
4811 * This may drop the filedesc lock, so the 'fp' cannot be
4812 * accessed after this call.
4813 */
4814 error = fo_fill_kinfo(fp, kif, fdp);
4815 if (error == 0)
4816 kif->kf_status |= KF_ATTR_VALID;
4817 if ((flags & KERN_FILEDESC_PACK_KINFO) != 0)
4818 pack_kinfo(kif);
4819 else
4820 kif->kf_structsize = roundup2(sizeof(*kif), sizeof(uint64_t));
4821 }
4822
4823 static void
export_vnode_to_kinfo(struct vnode * vp,int fd,int fflags,struct kinfo_file * kif,int flags)4824 export_vnode_to_kinfo(struct vnode *vp, int fd, int fflags,
4825 struct kinfo_file *kif, int flags)
4826 {
4827 int error;
4828
4829 bzero(kif, sizeof(*kif));
4830
4831 kif->kf_type = KF_TYPE_VNODE;
4832 error = vn_fill_kinfo_vnode(vp, kif);
4833 if (error == 0)
4834 kif->kf_status |= KF_ATTR_VALID;
4835 kif->kf_flags = xlate_fflags(fflags);
4836 cap_rights_init_zero(&kif->kf_cap_rights);
4837 kif->kf_fd = fd;
4838 kif->kf_ref_count = -1;
4839 kif->kf_offset = -1;
4840 if ((flags & KERN_FILEDESC_PACK_KINFO) != 0)
4841 pack_kinfo(kif);
4842 else
4843 kif->kf_structsize = roundup2(sizeof(*kif), sizeof(uint64_t));
4844 vrele(vp);
4845 }
4846
4847 struct export_fd_buf {
4848 struct filedesc *fdp;
4849 struct pwddesc *pdp;
4850 struct sbuf *sb;
4851 ssize_t remainder;
4852 struct kinfo_file kif;
4853 int flags;
4854 };
4855
4856 static int
export_kinfo_to_sb(struct export_fd_buf * efbuf)4857 export_kinfo_to_sb(struct export_fd_buf *efbuf)
4858 {
4859 struct kinfo_file *kif;
4860
4861 kif = &efbuf->kif;
4862 if (efbuf->remainder != -1) {
4863 if (efbuf->remainder < kif->kf_structsize)
4864 return (ENOMEM);
4865 efbuf->remainder -= kif->kf_structsize;
4866 }
4867 if (sbuf_bcat(efbuf->sb, kif, kif->kf_structsize) != 0)
4868 return (sbuf_error(efbuf->sb));
4869 return (0);
4870 }
4871
4872 static int
export_file_to_sb(struct file * fp,int fd,cap_rights_t * rightsp,struct export_fd_buf * efbuf)4873 export_file_to_sb(struct file *fp, int fd, cap_rights_t *rightsp,
4874 struct export_fd_buf *efbuf)
4875 {
4876 int error;
4877
4878 if (efbuf->remainder == 0)
4879 return (ENOMEM);
4880 export_file_to_kinfo(fp, fd, rightsp, &efbuf->kif, efbuf->fdp,
4881 efbuf->flags);
4882 FILEDESC_SUNLOCK(efbuf->fdp);
4883 error = export_kinfo_to_sb(efbuf);
4884 FILEDESC_SLOCK(efbuf->fdp);
4885 return (error);
4886 }
4887
4888 static int
export_vnode_to_sb(struct vnode * vp,int fd,int fflags,struct export_fd_buf * efbuf)4889 export_vnode_to_sb(struct vnode *vp, int fd, int fflags,
4890 struct export_fd_buf *efbuf)
4891 {
4892 int error;
4893
4894 if (efbuf->remainder == 0)
4895 return (ENOMEM);
4896 if (efbuf->pdp != NULL)
4897 PWDDESC_XUNLOCK(efbuf->pdp);
4898 export_vnode_to_kinfo(vp, fd, fflags, &efbuf->kif, efbuf->flags);
4899 error = export_kinfo_to_sb(efbuf);
4900 if (efbuf->pdp != NULL)
4901 PWDDESC_XLOCK(efbuf->pdp);
4902 return (error);
4903 }
4904
4905 /*
4906 * Store a process file descriptor information to sbuf.
4907 *
4908 * Takes a locked proc as argument, and returns with the proc unlocked.
4909 */
4910 int
kern_proc_filedesc_out(struct proc * p,struct sbuf * sb,ssize_t maxlen,int flags)4911 kern_proc_filedesc_out(struct proc *p, struct sbuf *sb, ssize_t maxlen,
4912 int flags)
4913 {
4914 struct file *fp;
4915 struct filedesc *fdp;
4916 struct pwddesc *pdp;
4917 struct export_fd_buf *efbuf;
4918 struct vnode *cttyvp, *textvp, *tracevp;
4919 struct pwd *pwd;
4920 int error, i;
4921 cap_rights_t rights;
4922
4923 PROC_LOCK_ASSERT(p, MA_OWNED);
4924
4925 /* ktrace vnode */
4926 tracevp = ktr_get_tracevp(p, true);
4927 /* text vnode */
4928 textvp = p->p_textvp;
4929 if (textvp != NULL)
4930 vrefact(textvp);
4931 /* Controlling tty. */
4932 cttyvp = NULL;
4933 if (p->p_pgrp != NULL && p->p_pgrp->pg_session != NULL) {
4934 cttyvp = p->p_pgrp->pg_session->s_ttyvp;
4935 if (cttyvp != NULL)
4936 vrefact(cttyvp);
4937 }
4938 fdp = fdhold(p);
4939 pdp = pdhold(p);
4940 PROC_UNLOCK(p);
4941
4942 efbuf = malloc(sizeof(*efbuf), M_TEMP, M_WAITOK);
4943 efbuf->fdp = NULL;
4944 efbuf->pdp = NULL;
4945 efbuf->sb = sb;
4946 efbuf->remainder = maxlen;
4947 efbuf->flags = flags;
4948
4949 error = 0;
4950 if (tracevp != NULL)
4951 error = export_vnode_to_sb(tracevp, KF_FD_TYPE_TRACE,
4952 FREAD | FWRITE, efbuf);
4953 if (error == 0 && textvp != NULL)
4954 error = export_vnode_to_sb(textvp, KF_FD_TYPE_TEXT, FREAD,
4955 efbuf);
4956 if (error == 0 && cttyvp != NULL)
4957 error = export_vnode_to_sb(cttyvp, KF_FD_TYPE_CTTY,
4958 FREAD | FWRITE, efbuf);
4959 if (error != 0 || pdp == NULL || fdp == NULL)
4960 goto fail;
4961 efbuf->fdp = fdp;
4962 efbuf->pdp = pdp;
4963 PWDDESC_XLOCK(pdp);
4964 pwd = pwd_hold_pwddesc(pdp);
4965 if (pwd != NULL) {
4966 /* working directory */
4967 if (pwd->pwd_cdir != NULL) {
4968 vrefact(pwd->pwd_cdir);
4969 error = export_vnode_to_sb(pwd->pwd_cdir,
4970 KF_FD_TYPE_CWD, FREAD, efbuf);
4971 }
4972 /* root directory */
4973 if (error == 0 && pwd->pwd_rdir != NULL) {
4974 vrefact(pwd->pwd_rdir);
4975 error = export_vnode_to_sb(pwd->pwd_rdir,
4976 KF_FD_TYPE_ROOT, FREAD, efbuf);
4977 }
4978 /* jail directory */
4979 if (error == 0 && pwd->pwd_jdir != NULL) {
4980 vrefact(pwd->pwd_jdir);
4981 error = export_vnode_to_sb(pwd->pwd_jdir,
4982 KF_FD_TYPE_JAIL, FREAD, efbuf);
4983 }
4984 }
4985 PWDDESC_XUNLOCK(pdp);
4986 if (error != 0)
4987 goto fail;
4988 if (pwd != NULL)
4989 pwd_drop(pwd);
4990 FILEDESC_SLOCK(fdp);
4991 if (refcount_load(&fdp->fd_refcnt) == 0)
4992 goto skip;
4993 FILEDESC_FOREACH_FP(fdp, i, fp) {
4994 #ifdef CAPABILITIES
4995 rights = *cap_rights(fdp, i);
4996 #else /* !CAPABILITIES */
4997 rights = cap_no_rights;
4998 #endif
4999 /*
5000 * Create sysctl entry. It is OK to drop the filedesc
5001 * lock inside of export_file_to_sb() as we will
5002 * re-validate and re-evaluate its properties when the
5003 * loop continues.
5004 */
5005 error = export_file_to_sb(fp, i, &rights, efbuf);
5006 if (error != 0 || refcount_load(&fdp->fd_refcnt) == 0)
5007 break;
5008 }
5009 skip:
5010 FILEDESC_SUNLOCK(fdp);
5011 fail:
5012 if (fdp != NULL)
5013 fddrop(fdp);
5014 if (pdp != NULL)
5015 pddrop(pdp);
5016 free(efbuf, M_TEMP);
5017 return (error);
5018 }
5019
5020 #define FILEDESC_SBUF_SIZE (sizeof(struct kinfo_file) * 5)
5021
5022 /*
5023 * Get per-process file descriptors for use by procstat(1), et al.
5024 */
5025 static int
sysctl_kern_proc_filedesc(SYSCTL_HANDLER_ARGS)5026 sysctl_kern_proc_filedesc(SYSCTL_HANDLER_ARGS)
5027 {
5028 struct sbuf sb;
5029 struct proc *p;
5030 ssize_t maxlen;
5031 u_int namelen;
5032 int error, error2, *name;
5033
5034 namelen = arg2;
5035 if (namelen != 1)
5036 return (EINVAL);
5037
5038 name = (int *)arg1;
5039
5040 sbuf_new_for_sysctl(&sb, NULL, FILEDESC_SBUF_SIZE, req);
5041 sbuf_clear_flags(&sb, SBUF_INCLUDENUL);
5042 error = pget((pid_t)name[0], PGET_CANDEBUG | PGET_NOTWEXIT, &p);
5043 if (error != 0) {
5044 sbuf_delete(&sb);
5045 return (error);
5046 }
5047 maxlen = req->oldptr != NULL ? req->oldlen : -1;
5048 error = kern_proc_filedesc_out(p, &sb, maxlen,
5049 KERN_FILEDESC_PACK_KINFO);
5050 error2 = sbuf_finish(&sb);
5051 sbuf_delete(&sb);
5052 return (error != 0 ? error : error2);
5053 }
5054
5055 #ifdef COMPAT_FREEBSD7
5056 #ifdef KINFO_OFILE_SIZE
5057 CTASSERT(sizeof(struct kinfo_ofile) == KINFO_OFILE_SIZE);
5058 #endif
5059
5060 static void
kinfo_to_okinfo(struct kinfo_file * kif,struct kinfo_ofile * okif)5061 kinfo_to_okinfo(struct kinfo_file *kif, struct kinfo_ofile *okif)
5062 {
5063
5064 okif->kf_structsize = sizeof(*okif);
5065 okif->kf_type = kif->kf_type;
5066 okif->kf_fd = kif->kf_fd;
5067 okif->kf_ref_count = kif->kf_ref_count;
5068 okif->kf_flags = kif->kf_flags & (KF_FLAG_READ | KF_FLAG_WRITE |
5069 KF_FLAG_APPEND | KF_FLAG_ASYNC | KF_FLAG_FSYNC | KF_FLAG_NONBLOCK |
5070 KF_FLAG_DIRECT | KF_FLAG_HASLOCK);
5071 okif->kf_offset = kif->kf_offset;
5072 if (kif->kf_type == KF_TYPE_VNODE)
5073 okif->kf_vnode_type = kif->kf_un.kf_file.kf_file_type;
5074 else
5075 okif->kf_vnode_type = KF_VTYPE_VNON;
5076 strlcpy(okif->kf_path, kif->kf_path, sizeof(okif->kf_path));
5077 if (kif->kf_type == KF_TYPE_SOCKET) {
5078 okif->kf_sock_domain = kif->kf_un.kf_sock.kf_sock_domain0;
5079 okif->kf_sock_type = kif->kf_un.kf_sock.kf_sock_type0;
5080 okif->kf_sock_protocol = kif->kf_un.kf_sock.kf_sock_protocol0;
5081 okif->kf_sa_local = kif->kf_un.kf_sock.kf_sa_local;
5082 okif->kf_sa_peer = kif->kf_un.kf_sock.kf_sa_peer;
5083 } else {
5084 okif->kf_sa_local.ss_family = AF_UNSPEC;
5085 okif->kf_sa_peer.ss_family = AF_UNSPEC;
5086 }
5087 }
5088
5089 static int
export_vnode_for_osysctl(struct vnode * vp,int type,struct kinfo_file * kif,struct kinfo_ofile * okif,struct pwddesc * pdp,struct sysctl_req * req)5090 export_vnode_for_osysctl(struct vnode *vp, int type, struct kinfo_file *kif,
5091 struct kinfo_ofile *okif, struct pwddesc *pdp, struct sysctl_req *req)
5092 {
5093 int error;
5094
5095 vrefact(vp);
5096 PWDDESC_XUNLOCK(pdp);
5097 export_vnode_to_kinfo(vp, type, 0, kif, KERN_FILEDESC_PACK_KINFO);
5098 kinfo_to_okinfo(kif, okif);
5099 error = SYSCTL_OUT(req, okif, sizeof(*okif));
5100 PWDDESC_XLOCK(pdp);
5101 return (error);
5102 }
5103
5104 /*
5105 * Get per-process file descriptors for use by procstat(1), et al.
5106 */
5107 static int
sysctl_kern_proc_ofiledesc(SYSCTL_HANDLER_ARGS)5108 sysctl_kern_proc_ofiledesc(SYSCTL_HANDLER_ARGS)
5109 {
5110 struct kinfo_ofile *okif;
5111 struct kinfo_file *kif;
5112 struct filedesc *fdp;
5113 struct pwddesc *pdp;
5114 struct pwd *pwd;
5115 u_int namelen;
5116 int error, i, *name;
5117 struct file *fp;
5118 struct proc *p;
5119
5120 namelen = arg2;
5121 if (namelen != 1)
5122 return (EINVAL);
5123
5124 name = (int *)arg1;
5125 error = pget((pid_t)name[0], PGET_CANDEBUG | PGET_NOTWEXIT, &p);
5126 if (error != 0)
5127 return (error);
5128 fdp = fdhold(p);
5129 if (fdp != NULL)
5130 pdp = pdhold(p);
5131 PROC_UNLOCK(p);
5132 if (fdp == NULL || pdp == NULL) {
5133 if (fdp != NULL)
5134 fddrop(fdp);
5135 return (ENOENT);
5136 }
5137 kif = malloc(sizeof(*kif), M_TEMP, M_WAITOK);
5138 okif = malloc(sizeof(*okif), M_TEMP, M_WAITOK | M_ZERO);
5139 PWDDESC_XLOCK(pdp);
5140 pwd = pwd_hold_pwddesc(pdp);
5141 if (pwd != NULL) {
5142 if (pwd->pwd_cdir != NULL)
5143 export_vnode_for_osysctl(pwd->pwd_cdir, KF_FD_TYPE_CWD, kif,
5144 okif, pdp, req);
5145 if (pwd->pwd_rdir != NULL)
5146 export_vnode_for_osysctl(pwd->pwd_rdir, KF_FD_TYPE_ROOT, kif,
5147 okif, pdp, req);
5148 if (pwd->pwd_jdir != NULL)
5149 export_vnode_for_osysctl(pwd->pwd_jdir, KF_FD_TYPE_JAIL, kif,
5150 okif, pdp, req);
5151 }
5152 PWDDESC_XUNLOCK(pdp);
5153 if (pwd != NULL)
5154 pwd_drop(pwd);
5155 FILEDESC_SLOCK(fdp);
5156 if (refcount_load(&fdp->fd_refcnt) == 0)
5157 goto skip;
5158 FILEDESC_FOREACH_FP(fdp, i, fp) {
5159 export_file_to_kinfo(fp, i, NULL, kif, fdp,
5160 KERN_FILEDESC_PACK_KINFO);
5161 FILEDESC_SUNLOCK(fdp);
5162 kinfo_to_okinfo(kif, okif);
5163 error = SYSCTL_OUT(req, okif, sizeof(*okif));
5164 FILEDESC_SLOCK(fdp);
5165 if (error != 0 || refcount_load(&fdp->fd_refcnt) == 0)
5166 break;
5167 }
5168 skip:
5169 FILEDESC_SUNLOCK(fdp);
5170 fddrop(fdp);
5171 pddrop(pdp);
5172 free(kif, M_TEMP);
5173 free(okif, M_TEMP);
5174 return (0);
5175 }
5176
5177 static SYSCTL_NODE(_kern_proc, KERN_PROC_OFILEDESC, ofiledesc,
5178 CTLFLAG_RD|CTLFLAG_MPSAFE, sysctl_kern_proc_ofiledesc,
5179 "Process ofiledesc entries");
5180 #endif /* COMPAT_FREEBSD7 */
5181
5182 int
vntype_to_kinfo(int vtype)5183 vntype_to_kinfo(int vtype)
5184 {
5185 struct {
5186 int vtype;
5187 int kf_vtype;
5188 } vtypes_table[] = {
5189 { VBAD, KF_VTYPE_VBAD },
5190 { VBLK, KF_VTYPE_VBLK },
5191 { VCHR, KF_VTYPE_VCHR },
5192 { VDIR, KF_VTYPE_VDIR },
5193 { VFIFO, KF_VTYPE_VFIFO },
5194 { VLNK, KF_VTYPE_VLNK },
5195 { VNON, KF_VTYPE_VNON },
5196 { VREG, KF_VTYPE_VREG },
5197 { VSOCK, KF_VTYPE_VSOCK }
5198 };
5199 unsigned int i;
5200
5201 /*
5202 * Perform vtype translation.
5203 */
5204 for (i = 0; i < nitems(vtypes_table); i++)
5205 if (vtypes_table[i].vtype == vtype)
5206 return (vtypes_table[i].kf_vtype);
5207
5208 return (KF_VTYPE_UNKNOWN);
5209 }
5210
5211 static SYSCTL_NODE(_kern_proc, KERN_PROC_FILEDESC, filedesc,
5212 CTLFLAG_RD|CTLFLAG_MPSAFE, sysctl_kern_proc_filedesc,
5213 "Process filedesc entries");
5214
5215 /*
5216 * Store a process current working directory information to sbuf.
5217 *
5218 * Takes a locked proc as argument, and returns with the proc unlocked.
5219 */
5220 int
kern_proc_cwd_out(struct proc * p,struct sbuf * sb,ssize_t maxlen)5221 kern_proc_cwd_out(struct proc *p, struct sbuf *sb, ssize_t maxlen)
5222 {
5223 struct pwddesc *pdp;
5224 struct pwd *pwd;
5225 struct export_fd_buf *efbuf;
5226 struct vnode *cdir;
5227 int error;
5228
5229 PROC_LOCK_ASSERT(p, MA_OWNED);
5230
5231 pdp = pdhold(p);
5232 PROC_UNLOCK(p);
5233 if (pdp == NULL)
5234 return (EINVAL);
5235
5236 efbuf = malloc(sizeof(*efbuf), M_TEMP, M_WAITOK);
5237 efbuf->fdp = NULL;
5238 efbuf->pdp = pdp;
5239 efbuf->sb = sb;
5240 efbuf->remainder = maxlen;
5241 efbuf->flags = 0;
5242
5243 PWDDESC_XLOCK(pdp);
5244 pwd = PWDDESC_XLOCKED_LOAD_PWD(pdp);
5245 cdir = pwd->pwd_cdir;
5246 if (cdir == NULL) {
5247 error = EINVAL;
5248 } else {
5249 vrefact(cdir);
5250 error = export_vnode_to_sb(cdir, KF_FD_TYPE_CWD, FREAD, efbuf);
5251 }
5252 PWDDESC_XUNLOCK(pdp);
5253 pddrop(pdp);
5254 free(efbuf, M_TEMP);
5255 return (error);
5256 }
5257
5258 /*
5259 * Get per-process current working directory.
5260 */
5261 static int
sysctl_kern_proc_cwd(SYSCTL_HANDLER_ARGS)5262 sysctl_kern_proc_cwd(SYSCTL_HANDLER_ARGS)
5263 {
5264 struct sbuf sb;
5265 struct proc *p;
5266 ssize_t maxlen;
5267 u_int namelen;
5268 int error, error2, *name;
5269
5270 namelen = arg2;
5271 if (namelen != 1)
5272 return (EINVAL);
5273
5274 name = (int *)arg1;
5275
5276 sbuf_new_for_sysctl(&sb, NULL, sizeof(struct kinfo_file), req);
5277 sbuf_clear_flags(&sb, SBUF_INCLUDENUL);
5278 error = pget((pid_t)name[0], PGET_CANDEBUG | PGET_NOTWEXIT, &p);
5279 if (error != 0) {
5280 sbuf_delete(&sb);
5281 return (error);
5282 }
5283 maxlen = req->oldptr != NULL ? req->oldlen : -1;
5284 error = kern_proc_cwd_out(p, &sb, maxlen);
5285 error2 = sbuf_finish(&sb);
5286 sbuf_delete(&sb);
5287 return (error != 0 ? error : error2);
5288 }
5289
5290 static SYSCTL_NODE(_kern_proc, KERN_PROC_CWD, cwd, CTLFLAG_RD|CTLFLAG_MPSAFE,
5291 sysctl_kern_proc_cwd, "Process current working directory");
5292
5293 #ifdef DDB
5294 /*
5295 * For the purposes of debugging, generate a human-readable string for the
5296 * file type.
5297 */
5298 static const char *
file_type_to_name(short type)5299 file_type_to_name(short type)
5300 {
5301
5302 switch (type) {
5303 case 0:
5304 return ("zero");
5305 case DTYPE_VNODE:
5306 return ("vnode");
5307 case DTYPE_SOCKET:
5308 return ("socket");
5309 case DTYPE_PIPE:
5310 return ("pipe");
5311 case DTYPE_FIFO:
5312 return ("fifo");
5313 case DTYPE_KQUEUE:
5314 return ("kqueue");
5315 case DTYPE_CRYPTO:
5316 return ("crypto");
5317 case DTYPE_MQUEUE:
5318 return ("mqueue");
5319 case DTYPE_SHM:
5320 return ("shm");
5321 case DTYPE_SEM:
5322 return ("ksem");
5323 case DTYPE_PTS:
5324 return ("pts");
5325 case DTYPE_DEV:
5326 return ("dev");
5327 case DTYPE_PROCDESC:
5328 return ("proc");
5329 case DTYPE_EVENTFD:
5330 return ("eventfd");
5331 case DTYPE_TIMERFD:
5332 return ("timerfd");
5333 case DTYPE_JAILDESC:
5334 return ("jail");
5335 default:
5336 return ("unkn");
5337 }
5338 }
5339
5340 /*
5341 * For the purposes of debugging, identify a process (if any, perhaps one of
5342 * many) that references the passed file in its file descriptor array. Return
5343 * NULL if none.
5344 */
5345 static struct proc *
file_to_first_proc(struct file * fp)5346 file_to_first_proc(struct file *fp)
5347 {
5348 struct filedesc *fdp;
5349 struct proc *p;
5350 int n;
5351
5352 FOREACH_PROC_IN_SYSTEM(p) {
5353 if (p->p_state == PRS_NEW)
5354 continue;
5355 fdp = p->p_fd;
5356 if (fdp == NULL)
5357 continue;
5358 for (n = 0; n < fdp->fd_nfiles; n++) {
5359 if (fp == fdp->fd_ofiles[n].fde_file)
5360 return (p);
5361 }
5362 }
5363 return (NULL);
5364 }
5365
5366 static void
db_print_file(struct file * fp,int header)5367 db_print_file(struct file *fp, int header)
5368 {
5369 #define XPTRWIDTH ((int)howmany(sizeof(void *) * NBBY, 4))
5370 struct proc *p;
5371
5372 if (header)
5373 db_printf("%*s %6s %*s %8s %4s %5s %6s %*s %5s %s\n",
5374 XPTRWIDTH, "File", "Type", XPTRWIDTH, "Data", "Flag",
5375 "GCFl", "Count", "MCount", XPTRWIDTH, "Vnode", "FPID",
5376 "FCmd");
5377 p = file_to_first_proc(fp);
5378 db_printf("%*p %6s %*p %08x %04x %5d %6d %*p %5d %s\n", XPTRWIDTH,
5379 fp, file_type_to_name(fp->f_type), XPTRWIDTH, fp->f_data,
5380 fp->f_flag, 0, refcount_load(&fp->f_count), 0, XPTRWIDTH, fp->f_vnode,
5381 p != NULL ? p->p_pid : -1, p != NULL ? p->p_comm : "-");
5382
5383 #undef XPTRWIDTH
5384 }
5385
DB_SHOW_COMMAND(file,db_show_file)5386 DB_SHOW_COMMAND(file, db_show_file)
5387 {
5388 struct file *fp;
5389
5390 if (!have_addr) {
5391 db_printf("usage: show file <addr>\n");
5392 return;
5393 }
5394 fp = (struct file *)addr;
5395 db_print_file(fp, 1);
5396 }
5397
DB_SHOW_COMMAND_FLAGS(files,db_show_files,DB_CMD_MEMSAFE)5398 DB_SHOW_COMMAND_FLAGS(files, db_show_files, DB_CMD_MEMSAFE)
5399 {
5400 struct filedesc *fdp;
5401 struct file *fp;
5402 struct proc *p;
5403 int header;
5404 int n;
5405
5406 header = 1;
5407 FOREACH_PROC_IN_SYSTEM(p) {
5408 if (p->p_state == PRS_NEW)
5409 continue;
5410 if ((fdp = p->p_fd) == NULL)
5411 continue;
5412 for (n = 0; n < fdp->fd_nfiles; ++n) {
5413 if ((fp = fdp->fd_ofiles[n].fde_file) == NULL)
5414 continue;
5415 db_print_file(fp, header);
5416 header = 0;
5417 }
5418 }
5419 }
5420 #endif
5421
5422 SYSCTL_INT(_kern, KERN_MAXFILESPERPROC, maxfilesperproc,
5423 CTLFLAG_RWTUN | CTLFLAG_NOFETCH,
5424 &maxfilesperproc, 0, "Maximum files allowed open per process");
5425
5426 SYSCTL_INT(_kern, KERN_MAXFILES, maxfiles, CTLFLAG_RWTUN | CTLFLAG_NOFETCH,
5427 &maxfiles, 0, "Maximum number of files");
5428
5429 SYSCTL_INT(_kern, OID_AUTO, openfiles, CTLFLAG_RD,
5430 &openfiles, 0, "System-wide number of open files");
5431
5432 /* ARGSUSED*/
5433 static void
filelistinit(void * dummy)5434 filelistinit(void *dummy)
5435 {
5436
5437 file_zone = uma_zcreate("Files", sizeof(struct file), NULL, NULL,
5438 NULL, NULL, UMA_ALIGN_PTR, UMA_ZONE_NOFREE);
5439 filedesc0_zone = uma_zcreate("filedesc0", sizeof(struct filedesc0),
5440 NULL, NULL, NULL, NULL, UMA_ALIGN_PTR, 0);
5441 pwd_zone = uma_zcreate("PWD", sizeof(struct pwd), NULL, NULL,
5442 NULL, NULL, UMA_ALIGN_PTR, UMA_ZONE_SMR);
5443 /*
5444 * XXXMJG this is a temporary hack due to boot ordering issues against
5445 * the vnode zone.
5446 */
5447 vfs_smr = uma_zone_get_smr(pwd_zone);
5448 mtx_init(&sigio_lock, "sigio lock", NULL, MTX_DEF);
5449 }
5450 SYSINIT(select, SI_SUB_LOCK, SI_ORDER_FIRST, filelistinit, NULL);
5451
5452 /*-------------------------------------------------------------------*/
5453
5454 static int
badfo_readwrite(struct file * fp,struct uio * uio,struct ucred * active_cred,int flags,struct thread * td)5455 badfo_readwrite(struct file *fp, struct uio *uio, struct ucred *active_cred,
5456 int flags, struct thread *td)
5457 {
5458
5459 return (EBADF);
5460 }
5461
5462 static int
badfo_truncate(struct file * fp,off_t length,struct ucred * active_cred,struct thread * td)5463 badfo_truncate(struct file *fp, off_t length, struct ucred *active_cred,
5464 struct thread *td)
5465 {
5466
5467 return (EINVAL);
5468 }
5469
5470 static int
badfo_ioctl(struct file * fp,u_long com,void * data,struct ucred * active_cred,struct thread * td)5471 badfo_ioctl(struct file *fp, u_long com, void *data, struct ucred *active_cred,
5472 struct thread *td)
5473 {
5474
5475 return (EBADF);
5476 }
5477
5478 static int
badfo_poll(struct file * fp,int events,struct ucred * active_cred,struct thread * td)5479 badfo_poll(struct file *fp, int events, struct ucred *active_cred,
5480 struct thread *td)
5481 {
5482
5483 return (0);
5484 }
5485
5486 static int
badfo_kqfilter(struct file * fp,struct knote * kn)5487 badfo_kqfilter(struct file *fp, struct knote *kn)
5488 {
5489
5490 return (EBADF);
5491 }
5492
5493 static int
badfo_stat(struct file * fp,struct stat * sb,struct ucred * active_cred)5494 badfo_stat(struct file *fp, struct stat *sb, struct ucred *active_cred)
5495 {
5496
5497 return (EBADF);
5498 }
5499
5500 static int
badfo_close(struct file * fp,struct thread * td)5501 badfo_close(struct file *fp, struct thread *td)
5502 {
5503
5504 return (0);
5505 }
5506
5507 static int
badfo_chmod(struct file * fp,mode_t mode,struct ucred * active_cred,struct thread * td)5508 badfo_chmod(struct file *fp, mode_t mode, struct ucred *active_cred,
5509 struct thread *td)
5510 {
5511
5512 return (EBADF);
5513 }
5514
5515 static int
badfo_chown(struct file * fp,uid_t uid,gid_t gid,struct ucred * active_cred,struct thread * td)5516 badfo_chown(struct file *fp, uid_t uid, gid_t gid, struct ucred *active_cred,
5517 struct thread *td)
5518 {
5519
5520 return (EBADF);
5521 }
5522
5523 static int
badfo_sendfile(struct file * fp,int sockfd,struct uio * hdr_uio,struct uio * trl_uio,off_t offset,size_t nbytes,off_t * sent,int flags,struct thread * td)5524 badfo_sendfile(struct file *fp, int sockfd, struct uio *hdr_uio,
5525 struct uio *trl_uio, off_t offset, size_t nbytes, off_t *sent, int flags,
5526 struct thread *td)
5527 {
5528
5529 return (EBADF);
5530 }
5531
5532 static int
badfo_fill_kinfo(struct file * fp,struct kinfo_file * kif,struct filedesc * fdp)5533 badfo_fill_kinfo(struct file *fp, struct kinfo_file *kif, struct filedesc *fdp)
5534 {
5535
5536 return (0);
5537 }
5538
5539 const struct fileops badfileops = {
5540 .fo_read = badfo_readwrite,
5541 .fo_write = badfo_readwrite,
5542 .fo_truncate = badfo_truncate,
5543 .fo_ioctl = badfo_ioctl,
5544 .fo_poll = badfo_poll,
5545 .fo_kqfilter = badfo_kqfilter,
5546 .fo_stat = badfo_stat,
5547 .fo_close = badfo_close,
5548 .fo_chmod = badfo_chmod,
5549 .fo_chown = badfo_chown,
5550 .fo_sendfile = badfo_sendfile,
5551 .fo_fill_kinfo = badfo_fill_kinfo,
5552 };
5553
5554 static int
path_poll(struct file * fp,int events,struct ucred * active_cred,struct thread * td)5555 path_poll(struct file *fp, int events, struct ucred *active_cred,
5556 struct thread *td)
5557 {
5558 return (POLLNVAL);
5559 }
5560
5561 static int
path_close(struct file * fp,struct thread * td)5562 path_close(struct file *fp, struct thread *td)
5563 {
5564 MPASS(fp->f_type == DTYPE_VNODE);
5565 fp->f_ops = &badfileops;
5566 vrele(fp->f_vnode);
5567 return (0);
5568 }
5569
5570 const struct fileops path_fileops = {
5571 .fo_read = badfo_readwrite,
5572 .fo_write = badfo_readwrite,
5573 .fo_truncate = badfo_truncate,
5574 .fo_ioctl = badfo_ioctl,
5575 .fo_poll = path_poll,
5576 .fo_kqfilter = vn_kqfilter_opath,
5577 .fo_stat = vn_statfile,
5578 .fo_close = path_close,
5579 .fo_chmod = badfo_chmod,
5580 .fo_chown = badfo_chown,
5581 .fo_sendfile = badfo_sendfile,
5582 .fo_fill_kinfo = vn_fill_kinfo,
5583 .fo_cmp = vn_cmp,
5584 .fo_flags = DFLAG_PASSABLE,
5585 };
5586
5587 int
invfo_rdwr(struct file * fp,struct uio * uio,struct ucred * active_cred,int flags,struct thread * td)5588 invfo_rdwr(struct file *fp, struct uio *uio, struct ucred *active_cred,
5589 int flags, struct thread *td)
5590 {
5591
5592 return (EOPNOTSUPP);
5593 }
5594
5595 int
invfo_truncate(struct file * fp,off_t length,struct ucred * active_cred,struct thread * td)5596 invfo_truncate(struct file *fp, off_t length, struct ucred *active_cred,
5597 struct thread *td)
5598 {
5599
5600 return (EINVAL);
5601 }
5602
5603 int
invfo_ioctl(struct file * fp,u_long com,void * data,struct ucred * active_cred,struct thread * td)5604 invfo_ioctl(struct file *fp, u_long com, void *data,
5605 struct ucred *active_cred, struct thread *td)
5606 {
5607
5608 return (ENOTTY);
5609 }
5610
5611 int
invfo_poll(struct file * fp,int events,struct ucred * active_cred,struct thread * td)5612 invfo_poll(struct file *fp, int events, struct ucred *active_cred,
5613 struct thread *td)
5614 {
5615
5616 return (poll_no_poll(events));
5617 }
5618
5619 int
invfo_kqfilter(struct file * fp,struct knote * kn)5620 invfo_kqfilter(struct file *fp, struct knote *kn)
5621 {
5622
5623 return (EINVAL);
5624 }
5625
5626 int
invfo_chmod(struct file * fp,mode_t mode,struct ucred * active_cred,struct thread * td)5627 invfo_chmod(struct file *fp, mode_t mode, struct ucred *active_cred,
5628 struct thread *td)
5629 {
5630
5631 return (EINVAL);
5632 }
5633
5634 int
invfo_chown(struct file * fp,uid_t uid,gid_t gid,struct ucred * active_cred,struct thread * td)5635 invfo_chown(struct file *fp, uid_t uid, gid_t gid, struct ucred *active_cred,
5636 struct thread *td)
5637 {
5638
5639 return (EINVAL);
5640 }
5641
5642 int
invfo_sendfile(struct file * fp,int sockfd,struct uio * hdr_uio,struct uio * trl_uio,off_t offset,size_t nbytes,off_t * sent,int flags,struct thread * td)5643 invfo_sendfile(struct file *fp, int sockfd, struct uio *hdr_uio,
5644 struct uio *trl_uio, off_t offset, size_t nbytes, off_t *sent, int flags,
5645 struct thread *td)
5646 {
5647
5648 return (EINVAL);
5649 }
5650
5651 /*-------------------------------------------------------------------*/
5652
5653 /*
5654 * File Descriptor pseudo-device driver (/dev/fd/).
5655 *
5656 * Opening minor device N dup()s the file (if any) connected to file
5657 * descriptor N belonging to the calling process. Note that this driver
5658 * consists of only the ``open()'' routine, because all subsequent
5659 * references to this file will be direct to the other driver.
5660 *
5661 * XXX: we could give this one a cloning event handler if necessary.
5662 */
5663
5664 /* ARGSUSED */
5665 static int
fdopen(struct cdev * dev,int mode,int type,struct thread * td)5666 fdopen(struct cdev *dev, int mode, int type, struct thread *td)
5667 {
5668
5669 /*
5670 * XXX Kludge: set curthread->td_dupfd to contain the value of the
5671 * the file descriptor being sought for duplication. The error
5672 * return ensures that the vnode for this device will be released
5673 * by vn_open. Open will detect this special error and take the
5674 * actions in dupfdopen below. Other callers of vn_open or VOP_OPEN
5675 * will simply report the error.
5676 */
5677 td->td_dupfd = dev2unit(dev);
5678 return (ENODEV);
5679 }
5680
5681 static struct cdevsw fildesc_cdevsw = {
5682 .d_version = D_VERSION,
5683 .d_open = fdopen,
5684 .d_name = "FD",
5685 };
5686
5687 static void
fildesc_drvinit(void * unused)5688 fildesc_drvinit(void *unused)
5689 {
5690 struct cdev *dev;
5691
5692 dev = make_dev_credf(MAKEDEV_ETERNAL, &fildesc_cdevsw, 0, NULL,
5693 UID_ROOT, GID_WHEEL, 0666, "fd/0");
5694 make_dev_alias(dev, "stdin");
5695 dev = make_dev_credf(MAKEDEV_ETERNAL, &fildesc_cdevsw, 1, NULL,
5696 UID_ROOT, GID_WHEEL, 0666, "fd/1");
5697 make_dev_alias(dev, "stdout");
5698 dev = make_dev_credf(MAKEDEV_ETERNAL, &fildesc_cdevsw, 2, NULL,
5699 UID_ROOT, GID_WHEEL, 0666, "fd/2");
5700 make_dev_alias(dev, "stderr");
5701 }
5702
5703 SYSINIT(fildescdev, SI_SUB_DRIVERS, SI_ORDER_MIDDLE, fildesc_drvinit, NULL);
5704