1 /*-
2 * SPDX-License-Identifier: BSD-2-Clause
3 *
4 * Copyright (c) 1993, David Greenman
5 * All rights reserved.
6 *
7 * Redistribution and use in source and binary forms, with or without
8 * modification, are permitted provided that the following conditions
9 * are met:
10 * 1. Redistributions of source code must retain the above copyright
11 * notice, this list of conditions and the following disclaimer.
12 * 2. Redistributions in binary form must reproduce the above copyright
13 * notice, this list of conditions and the following disclaimer in the
14 * documentation and/or other materials provided with the distribution.
15 *
16 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
17 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
18 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
19 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
20 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
21 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
22 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
23 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
24 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
25 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
26 * SUCH DAMAGE.
27 */
28
29 #include <sys/cdefs.h>
30 #include "opt_capsicum.h"
31 #include "opt_hwpmc_hooks.h"
32 #include "opt_hwt_hooks.h"
33 #include "opt_ktrace.h"
34 #include "opt_vm.h"
35
36 #include <sys/param.h>
37 #include <sys/systm.h>
38 #include <sys/acct.h>
39 #include <sys/asan.h>
40 #include <sys/capsicum.h>
41 #include <sys/compressor.h>
42 #include <sys/eventhandler.h>
43 #include <sys/exec.h>
44 #include <sys/fcntl.h>
45 #include <sys/filedesc.h>
46 #include <sys/imgact.h>
47 #include <sys/imgact_elf.h>
48 #include <sys/kernel.h>
49 #include <sys/lock.h>
50 #include <sys/malloc.h>
51 #include <sys/mman.h>
52 #include <sys/mount.h>
53 #include <sys/mutex.h>
54 #include <sys/namei.h>
55 #include <sys/priv.h>
56 #include <sys/proc.h>
57 #include <sys/ptrace.h>
58 #include <sys/reg.h>
59 #include <sys/resourcevar.h>
60 #include <sys/rwlock.h>
61 #include <sys/sched.h>
62 #include <sys/sdt.h>
63 #include <sys/sf_buf.h>
64 #include <sys/shm.h>
65 #include <sys/signalvar.h>
66 #include <sys/smp.h>
67 #include <sys/stat.h>
68 #include <sys/syscallsubr.h>
69 #include <sys/sysctl.h>
70 #include <sys/sysent.h>
71 #include <sys/sysproto.h>
72 #include <sys/timers.h>
73 #include <sys/umtxvar.h>
74 #include <sys/vnode.h>
75 #include <sys/wait.h>
76 #ifdef KTRACE
77 #include <sys/ktrace.h>
78 #endif
79
80 #include <vm/vm.h>
81 #include <vm/vm_param.h>
82 #include <vm/pmap.h>
83 #include <vm/vm_page.h>
84 #include <vm/vm_map.h>
85 #include <vm/vm_kern.h>
86 #include <vm/vm_extern.h>
87 #include <vm/vm_object.h>
88 #include <vm/vm_pager.h>
89
90 #ifdef HWPMC_HOOKS
91 #include <sys/pmckern.h>
92 #endif
93
94 #ifdef HWT_HOOKS
95 #include <dev/hwt/hwt_hook.h>
96 #endif
97
98 #include <security/audit/audit.h>
99 #include <security/mac/mac_framework.h>
100
101 #ifdef KDTRACE_HOOKS
102 #include <sys/dtrace_bsd.h>
103 dtrace_execexit_func_t dtrace_fasttrap_exec;
104 #endif
105
106 SDT_PROVIDER_DECLARE(proc);
107 SDT_PROBE_DEFINE1(proc, , , exec, "char *");
108 SDT_PROBE_DEFINE1(proc, , , exec__failure, "int");
109 SDT_PROBE_DEFINE1(proc, , , exec__success, "char *");
110
111 MALLOC_DEFINE(M_PARGS, "proc-args", "Process arguments");
112
113 int coredump_pack_fileinfo = 1;
114 SYSCTL_INT(_kern, OID_AUTO, coredump_pack_fileinfo, CTLFLAG_RWTUN,
115 &coredump_pack_fileinfo, 0,
116 "Enable file path packing in 'procstat -f' coredump notes");
117
118 int coredump_pack_vmmapinfo = 1;
119 SYSCTL_INT(_kern, OID_AUTO, coredump_pack_vmmapinfo, CTLFLAG_RWTUN,
120 &coredump_pack_vmmapinfo, 0,
121 "Enable file path packing in 'procstat -v' coredump notes");
122
123 static int sysctl_kern_ps_strings(SYSCTL_HANDLER_ARGS);
124 static int sysctl_kern_usrstack(SYSCTL_HANDLER_ARGS);
125 static int sysctl_kern_stackprot(SYSCTL_HANDLER_ARGS);
126 static int do_execve(struct thread *td, struct image_args *args,
127 struct mac *mac_p, struct vmspace *oldvmspace);
128
129 /* XXX This should be vm_size_t. */
130 SYSCTL_PROC(_kern, KERN_PS_STRINGS, ps_strings, CTLTYPE_ULONG|CTLFLAG_RD|
131 CTLFLAG_CAPRD|CTLFLAG_MPSAFE, NULL, 0, sysctl_kern_ps_strings, "LU",
132 "Location of process' ps_strings structure");
133
134 /* XXX This should be vm_size_t. */
135 SYSCTL_PROC(_kern, KERN_USRSTACK, usrstack, CTLTYPE_ULONG|CTLFLAG_RD|
136 CTLFLAG_CAPRD|CTLFLAG_MPSAFE, NULL, 0, sysctl_kern_usrstack, "LU",
137 "Top of process stack");
138
139 SYSCTL_PROC(_kern, OID_AUTO, stackprot, CTLTYPE_INT|CTLFLAG_RD|CTLFLAG_MPSAFE,
140 NULL, 0, sysctl_kern_stackprot, "I",
141 "Stack memory permissions");
142
143 u_long ps_arg_cache_limit = PAGE_SIZE / 16;
144 SYSCTL_ULONG(_kern, OID_AUTO, ps_arg_cache_limit, CTLFLAG_RW,
145 &ps_arg_cache_limit, 0,
146 "Process' command line characters cache limit");
147
148 static int disallow_high_osrel;
149 SYSCTL_INT(_kern, OID_AUTO, disallow_high_osrel, CTLFLAG_RW,
150 &disallow_high_osrel, 0,
151 "Disallow execution of binaries built for higher version of the world");
152
153 static int map_at_zero = 0;
154 SYSCTL_INT(_security_bsd, OID_AUTO, map_at_zero, CTLFLAG_RWTUN, &map_at_zero, 0,
155 "Permit processes to map an object at virtual address 0.");
156
157 static int core_dump_can_intr = 1;
158 SYSCTL_INT(_kern, OID_AUTO, core_dump_can_intr, CTLFLAG_RWTUN,
159 &core_dump_can_intr, 0,
160 "Core dumping interruptible with SIGKILL");
161
162 static int
sysctl_kern_ps_strings(SYSCTL_HANDLER_ARGS)163 sysctl_kern_ps_strings(SYSCTL_HANDLER_ARGS)
164 {
165 struct proc *p;
166 vm_offset_t ps_strings;
167
168 p = curproc;
169 #ifdef SCTL_MASK32
170 if (req->flags & SCTL_MASK32) {
171 unsigned int val;
172 val = (unsigned int)PROC_PS_STRINGS(p);
173 return (SYSCTL_OUT(req, &val, sizeof(val)));
174 }
175 #endif
176 ps_strings = PROC_PS_STRINGS(p);
177 return (SYSCTL_OUT(req, &ps_strings, sizeof(ps_strings)));
178 }
179
180 static int
sysctl_kern_usrstack(SYSCTL_HANDLER_ARGS)181 sysctl_kern_usrstack(SYSCTL_HANDLER_ARGS)
182 {
183 struct proc *p;
184 vm_offset_t val;
185
186 p = curproc;
187 #ifdef SCTL_MASK32
188 if (req->flags & SCTL_MASK32) {
189 unsigned int val32;
190
191 val32 = round_page((unsigned int)p->p_vmspace->vm_stacktop);
192 return (SYSCTL_OUT(req, &val32, sizeof(val32)));
193 }
194 #endif
195 val = round_page(p->p_vmspace->vm_stacktop);
196 return (SYSCTL_OUT(req, &val, sizeof(val)));
197 }
198
199 static int
sysctl_kern_stackprot(SYSCTL_HANDLER_ARGS)200 sysctl_kern_stackprot(SYSCTL_HANDLER_ARGS)
201 {
202 struct proc *p;
203
204 p = curproc;
205 return (SYSCTL_OUT(req, &p->p_sysent->sv_stackprot,
206 sizeof(p->p_sysent->sv_stackprot)));
207 }
208
209 /*
210 * Each of the items is a pointer to a `const struct execsw', hence the
211 * double pointer here.
212 */
213 static const struct execsw **execsw;
214
215 #ifndef _SYS_SYSPROTO_H_
216 struct execve_args {
217 char *fname;
218 char **argv;
219 char **envv;
220 };
221 #endif
222
223 int
sys_execve(struct thread * td,struct execve_args * uap)224 sys_execve(struct thread *td, struct execve_args *uap)
225 {
226 struct image_args args;
227 struct vmspace *oldvmspace;
228 int error;
229
230 error = pre_execve(td, &oldvmspace);
231 if (error != 0)
232 return (error);
233 error = exec_copyin_args(&args, uap->fname, uap->argv, uap->envv);
234 if (error == 0)
235 error = kern_execve(td, &args, NULL, oldvmspace);
236 post_execve(td, error, oldvmspace);
237 AUDIT_SYSCALL_EXIT(error == EJUSTRETURN ? 0 : error, td);
238 return (error);
239 }
240
241 #ifndef _SYS_SYSPROTO_H_
242 struct fexecve_args {
243 int fd;
244 char **argv;
245 char **envv;
246 };
247 #endif
248 int
sys_fexecve(struct thread * td,struct fexecve_args * uap)249 sys_fexecve(struct thread *td, struct fexecve_args *uap)
250 {
251 struct image_args args;
252 struct vmspace *oldvmspace;
253 int error;
254
255 error = pre_execve(td, &oldvmspace);
256 if (error != 0)
257 return (error);
258 error = exec_copyin_args(&args, NULL, uap->argv, uap->envv);
259 if (error == 0) {
260 args.fd = uap->fd;
261 error = kern_execve(td, &args, NULL, oldvmspace);
262 }
263 post_execve(td, error, oldvmspace);
264 AUDIT_SYSCALL_EXIT(error == EJUSTRETURN ? 0 : error, td);
265 return (error);
266 }
267
268 #ifndef _SYS_SYSPROTO_H_
269 struct __mac_execve_args {
270 char *fname;
271 char **argv;
272 char **envv;
273 struct mac *mac_p;
274 };
275 #endif
276
277 int
sys___mac_execve(struct thread * td,struct __mac_execve_args * uap)278 sys___mac_execve(struct thread *td, struct __mac_execve_args *uap)
279 {
280 #ifdef MAC
281 struct image_args args;
282 struct vmspace *oldvmspace;
283 int error;
284
285 error = pre_execve(td, &oldvmspace);
286 if (error != 0)
287 return (error);
288 error = exec_copyin_args(&args, uap->fname, uap->argv, uap->envv);
289 if (error == 0)
290 error = kern_execve(td, &args, uap->mac_p, oldvmspace);
291 post_execve(td, error, oldvmspace);
292 AUDIT_SYSCALL_EXIT(error == EJUSTRETURN ? 0 : error, td);
293 return (error);
294 #else
295 return (ENOSYS);
296 #endif
297 }
298
299 int
pre_execve(struct thread * td,struct vmspace ** oldvmspace)300 pre_execve(struct thread *td, struct vmspace **oldvmspace)
301 {
302 struct proc *p;
303 int error;
304
305 KASSERT(td == curthread, ("non-current thread %p", td));
306 error = 0;
307 p = td->td_proc;
308 if ((p->p_flag & P_HADTHREADS) != 0) {
309 PROC_LOCK(p);
310 if (thread_single(p, SINGLE_BOUNDARY) != 0)
311 error = ERESTART;
312 PROC_UNLOCK(p);
313 }
314 KASSERT(error != 0 || (td->td_pflags & TDP_EXECVMSPC) == 0,
315 ("nested execve"));
316 *oldvmspace = p->p_vmspace;
317 return (error);
318 }
319
320 void
post_execve(struct thread * td,int error,struct vmspace * oldvmspace)321 post_execve(struct thread *td, int error, struct vmspace *oldvmspace)
322 {
323 struct proc *p;
324
325 KASSERT(td == curthread, ("non-current thread %p", td));
326 p = td->td_proc;
327 if ((p->p_flag & P_HADTHREADS) != 0) {
328 PROC_LOCK(p);
329 /*
330 * If success, we upgrade to SINGLE_EXIT state to
331 * force other threads to suicide.
332 */
333 if (error == EJUSTRETURN)
334 thread_single(p, SINGLE_EXIT);
335 else
336 thread_single_end(p, SINGLE_BOUNDARY);
337 PROC_UNLOCK(p);
338 }
339 exec_cleanup(td, oldvmspace);
340 }
341
342 /*
343 * kern_execve() has the astonishing property of not always returning to
344 * the caller. If sufficiently bad things happen during the call to
345 * do_execve(), it can end up calling exit1(); as a result, callers must
346 * avoid doing anything which they might need to undo (e.g., allocating
347 * memory).
348 */
349 int
kern_execve(struct thread * td,struct image_args * args,struct mac * mac_p,struct vmspace * oldvmspace)350 kern_execve(struct thread *td, struct image_args *args, struct mac *mac_p,
351 struct vmspace *oldvmspace)
352 {
353
354 TSEXEC(td->td_proc->p_pid, args->begin_argv);
355 AUDIT_ARG_ARGV(args->begin_argv, args->argc,
356 exec_args_get_begin_envv(args) - args->begin_argv);
357 AUDIT_ARG_ENVV(exec_args_get_begin_envv(args), args->envc,
358 args->endp - exec_args_get_begin_envv(args));
359 #ifdef KTRACE
360 if (KTRPOINT(td, KTR_ARGS)) {
361 ktrdata(KTR_ARGS, args->begin_argv,
362 exec_args_get_begin_envv(args) - args->begin_argv);
363 }
364 if (KTRPOINT(td, KTR_ENVS)) {
365 ktrdata(KTR_ENVS, exec_args_get_begin_envv(args),
366 args->endp - exec_args_get_begin_envv(args));
367 }
368 #endif
369 /* Must have at least one argument. */
370 if (args->argc == 0) {
371 exec_free_args(args);
372 return (EINVAL);
373 }
374 return (do_execve(td, args, mac_p, oldvmspace));
375 }
376
377 static void
execve_nosetid(struct image_params * imgp)378 execve_nosetid(struct image_params *imgp)
379 {
380 imgp->credential_setid = false;
381 if (imgp->newcred != NULL) {
382 crfree(imgp->newcred);
383 imgp->newcred = NULL;
384 }
385 }
386
387 /*
388 * In-kernel implementation of execve(). All arguments are assumed to be
389 * userspace pointers from the passed thread.
390 */
391 static int
do_execve(struct thread * td,struct image_args * args,struct mac * mac_p,struct vmspace * oldvmspace)392 do_execve(struct thread *td, struct image_args *args, struct mac *mac_p,
393 struct vmspace *oldvmspace)
394 {
395 struct proc *p = td->td_proc;
396 struct nameidata nd;
397 struct ucred *oldcred;
398 struct uidinfo *euip = NULL;
399 uintptr_t stack_base;
400 struct image_params image_params, *imgp;
401 struct vattr attr;
402 struct pargs *oldargs = NULL, *newargs = NULL;
403 struct sigacts *oldsigacts = NULL, *newsigacts = NULL;
404 #ifdef KTRACE
405 struct ktr_io_params *kiop;
406 #endif
407 struct vnode *oldtextvp, *newtextvp;
408 struct vnode *oldtextdvp, *newtextdvp;
409 char *oldbinname, *newbinname;
410 bool credential_changing;
411 #ifdef MAC
412 struct label *interpvplabel = NULL;
413 bool will_transition;
414 #endif
415 #ifdef HWPMC_HOOKS
416 struct pmckern_procexec pe;
417 #endif
418 int error, i, orig_osrel;
419 uint32_t orig_fctl0;
420 Elf_Brandinfo *orig_brandinfo;
421 size_t freepath_size;
422 static const char fexecv_proc_title[] = "(fexecv)";
423
424 imgp = &image_params;
425 oldtextvp = oldtextdvp = NULL;
426 newtextvp = newtextdvp = NULL;
427 newbinname = oldbinname = NULL;
428 #ifdef KTRACE
429 kiop = NULL;
430 #endif
431
432 /*
433 * Lock the process and set the P_INEXEC flag to indicate that
434 * it should be left alone until we're done here. This is
435 * necessary to avoid race conditions - e.g. in ptrace() -
436 * that might allow a local user to illicitly obtain elevated
437 * privileges.
438 */
439 PROC_LOCK(p);
440 KASSERT((p->p_flag & P_INEXEC) == 0,
441 ("%s(): process already has P_INEXEC flag", __func__));
442 p->p_flag |= P_INEXEC;
443 PROC_UNLOCK(p);
444
445 /*
446 * Initialize part of the common data
447 */
448 bzero(imgp, sizeof(*imgp));
449 imgp->proc = p;
450 imgp->attr = &attr;
451 imgp->args = args;
452 oldcred = p->p_ucred;
453 orig_osrel = p->p_osrel;
454 orig_fctl0 = p->p_fctl0;
455 orig_brandinfo = p->p_elf_brandinfo;
456
457 #ifdef MAC
458 error = mac_execve_enter(imgp, mac_p);
459 if (error)
460 goto exec_fail;
461 #endif
462
463 SDT_PROBE1(proc, , , exec, args->fname);
464
465 interpret:
466 if (args->fname != NULL) {
467 #ifdef CAPABILITY_MODE
468 if (CAP_TRACING(td))
469 ktrcapfail(CAPFAIL_NAMEI, args->fname);
470 /*
471 * While capability mode can't reach this point via direct
472 * path arguments to execve(), we also don't allow
473 * interpreters to be used in capability mode (for now).
474 * Catch indirect lookups and return a permissions error.
475 */
476 if (IN_CAPABILITY_MODE(td)) {
477 error = ECAPMODE;
478 goto exec_fail;
479 }
480 #endif
481
482 /*
483 * Translate the file name. namei() returns a vnode
484 * pointer in ni_vp among other things.
485 */
486 NDINIT(&nd, LOOKUP, ISOPEN | LOCKLEAF | LOCKSHARED | FOLLOW |
487 AUDITVNODE1 | WANTPARENT, UIO_SYSSPACE,
488 args->fname);
489
490 error = namei(&nd);
491 if (error)
492 goto exec_fail;
493
494 newtextvp = nd.ni_vp;
495 newtextdvp = nd.ni_dvp;
496 nd.ni_dvp = NULL;
497 newbinname = malloc(nd.ni_cnd.cn_namelen + 1, M_PARGS,
498 M_WAITOK);
499 memcpy(newbinname, nd.ni_cnd.cn_nameptr, nd.ni_cnd.cn_namelen);
500 newbinname[nd.ni_cnd.cn_namelen] = '\0';
501 imgp->vp = newtextvp;
502
503 /*
504 * Do the best to calculate the full path to the image file.
505 */
506 if (args->fname[0] == '/') {
507 imgp->execpath = args->fname;
508 } else {
509 VOP_UNLOCK(imgp->vp);
510 freepath_size = MAXPATHLEN;
511 if (vn_fullpath_hardlink(newtextvp, newtextdvp,
512 newbinname, nd.ni_cnd.cn_namelen, &imgp->execpath,
513 &imgp->freepath, &freepath_size) != 0)
514 imgp->execpath = args->fname;
515 vn_lock(imgp->vp, LK_SHARED | LK_RETRY);
516 }
517 } else if (imgp->interpreter_vp) {
518 /*
519 * An image activator has already provided an open vnode
520 */
521 newtextvp = imgp->interpreter_vp;
522 imgp->interpreter_vp = NULL;
523 if (vn_fullpath(newtextvp, &imgp->execpath,
524 &imgp->freepath) != 0)
525 imgp->execpath = args->fname;
526 vn_lock(newtextvp, LK_SHARED | LK_RETRY);
527 AUDIT_ARG_VNODE1(newtextvp);
528 imgp->vp = newtextvp;
529 } else {
530 AUDIT_ARG_FD(args->fd);
531
532 /*
533 * If the descriptors was not opened with O_PATH, then
534 * we require that it was opened with O_EXEC or
535 * O_RDONLY. In either case, exec_check_permissions()
536 * below checks _current_ file access mode regardless
537 * of the permissions additionally checked at the
538 * open(2).
539 */
540 error = fgetvp_exec(td, args->fd, &cap_fexecve_rights,
541 &newtextvp);
542 if (error != 0)
543 goto exec_fail;
544
545 if (vn_fullpath(newtextvp, &imgp->execpath,
546 &imgp->freepath) != 0)
547 imgp->execpath = args->fname;
548 vn_lock(newtextvp, LK_SHARED | LK_RETRY);
549 AUDIT_ARG_VNODE1(newtextvp);
550 imgp->vp = newtextvp;
551 }
552
553 /*
554 * Check file permissions. Also 'opens' file and sets its vnode to
555 * text mode.
556 */
557 error = exec_check_permissions(imgp);
558 if (error)
559 goto exec_fail_dealloc;
560
561 imgp->object = imgp->vp->v_object;
562 if (imgp->object != NULL)
563 vm_object_reference(imgp->object);
564
565 error = exec_map_first_page(imgp);
566 if (error)
567 goto exec_fail_dealloc;
568
569 imgp->proc->p_osrel = 0;
570 imgp->proc->p_fctl0 = 0;
571 imgp->proc->p_elf_brandinfo = NULL;
572
573 /*
574 * Implement image setuid/setgid.
575 *
576 * Determine new credentials before attempting image activators
577 * so that it can be used by process_exec handlers to determine
578 * credential/setid changes.
579 *
580 * Don't honor setuid/setgid if the filesystem prohibits it or if
581 * the process is being traced.
582 *
583 * We disable setuid/setgid/etc in capability mode on the basis
584 * that most setugid applications are not written with that
585 * environment in mind, and will therefore almost certainly operate
586 * incorrectly. In principle there's no reason that setugid
587 * applications might not be useful in capability mode, so we may want
588 * to reconsider this conservative design choice in the future.
589 *
590 * XXXMAC: For the time being, use NOSUID to also prohibit
591 * transitions on the file system.
592 */
593 credential_changing = false;
594 credential_changing |= (attr.va_mode & S_ISUID) &&
595 oldcred->cr_uid != attr.va_uid;
596 credential_changing |= (attr.va_mode & S_ISGID) &&
597 oldcred->cr_gid != attr.va_gid;
598 #ifdef MAC
599 will_transition = mac_vnode_execve_will_transition(oldcred, imgp->vp,
600 interpvplabel, imgp) != 0;
601 credential_changing |= will_transition;
602 #endif
603
604 /* Don't inherit PROC_PDEATHSIG_CTL value if setuid/setgid. */
605 if (credential_changing)
606 imgp->proc->p_pdeathsig = 0;
607
608 if (credential_changing &&
609 #ifdef CAPABILITY_MODE
610 ((oldcred->cr_flags & CRED_FLAG_CAPMODE) == 0) &&
611 #endif
612 (imgp->vp->v_mount->mnt_flag & MNT_NOSUID) == 0 &&
613 (p->p_flag & P_TRACED) == 0) {
614 imgp->credential_setid = true;
615 VOP_UNLOCK(imgp->vp);
616 imgp->newcred = crdup(oldcred);
617 if (attr.va_mode & S_ISUID) {
618 euip = uifind(attr.va_uid);
619 change_euid(imgp->newcred, euip);
620 }
621 vn_lock(imgp->vp, LK_SHARED | LK_RETRY);
622 if (attr.va_mode & S_ISGID)
623 change_egid(imgp->newcred, attr.va_gid);
624 /*
625 * Implement correct POSIX saved-id behavior.
626 *
627 * XXXMAC: Note that the current logic will save the
628 * uid and gid if a MAC domain transition occurs, even
629 * though maybe it shouldn't.
630 */
631 change_svuid(imgp->newcred, imgp->newcred->cr_uid);
632 change_svgid(imgp->newcred, imgp->newcred->cr_gid);
633 } else {
634 /*
635 * Implement correct POSIX saved-id behavior.
636 *
637 * XXX: It's not clear that the existing behavior is
638 * POSIX-compliant. A number of sources indicate that the
639 * saved uid/gid should only be updated if the new ruid is
640 * not equal to the old ruid, or the new euid is not equal
641 * to the old euid and the new euid is not equal to the old
642 * ruid. The FreeBSD code always updates the saved uid/gid.
643 * Also, this code uses the new (replaced) euid and egid as
644 * the source, which may or may not be the right ones to use.
645 */
646 if (oldcred->cr_svuid != oldcred->cr_uid ||
647 oldcred->cr_svgid != oldcred->cr_gid) {
648 VOP_UNLOCK(imgp->vp);
649 imgp->newcred = crdup(oldcred);
650 vn_lock(imgp->vp, LK_SHARED | LK_RETRY);
651 change_svuid(imgp->newcred, imgp->newcred->cr_uid);
652 change_svgid(imgp->newcred, imgp->newcred->cr_gid);
653 }
654 }
655 /* The new credentials are installed into the process later. */
656
657 /*
658 * Loop through the list of image activators, calling each one.
659 * An activator returns -1 if there is no match, 0 on success,
660 * and an error otherwise.
661 */
662 error = -1;
663 for (i = 0; error == -1 && execsw[i]; ++i) {
664 if (execsw[i]->ex_imgact == NULL)
665 continue;
666 error = (*execsw[i]->ex_imgact)(imgp);
667 }
668
669 if (error) {
670 if (error == -1)
671 error = ENOEXEC;
672 goto exec_fail_dealloc;
673 }
674
675 /*
676 * Special interpreter operation, cleanup and loop up to try to
677 * activate the interpreter.
678 */
679 if (imgp->interpreted) {
680 exec_unmap_first_page(imgp);
681 /*
682 * The text reference needs to be removed for scripts.
683 * There is a short period before we determine that
684 * something is a script where text reference is active.
685 * The vnode lock is held over this entire period
686 * so nothing should illegitimately be blocked.
687 */
688 MPASS(imgp->textset);
689 VOP_UNSET_TEXT_CHECKED(newtextvp);
690 imgp->textset = false;
691 /* free name buffer and old vnode */
692 #ifdef MAC
693 mac_execve_interpreter_enter(newtextvp, &interpvplabel);
694 #endif
695 if (imgp->opened) {
696 VOP_CLOSE(newtextvp, FREAD, td->td_ucred, td);
697 imgp->opened = false;
698 }
699 vput(newtextvp);
700 imgp->vp = newtextvp = NULL;
701 if (args->fname != NULL) {
702 if (newtextdvp != NULL) {
703 vrele(newtextdvp);
704 newtextdvp = NULL;
705 }
706 NDFREE_PNBUF(&nd);
707 free(newbinname, M_PARGS);
708 newbinname = NULL;
709 }
710 vm_object_deallocate(imgp->object);
711 imgp->object = NULL;
712 execve_nosetid(imgp);
713 imgp->execpath = NULL;
714 free(imgp->freepath, M_TEMP);
715 imgp->freepath = NULL;
716 /* set new name to that of the interpreter */
717 if (imgp->interpreter_vp) {
718 args->fname = NULL;
719 } else {
720 args->fname = imgp->interpreter_name;
721 }
722 goto interpret;
723 }
724
725 /*
726 * NB: We unlock the vnode here because it is believed that none
727 * of the sv_copyout_strings/sv_fixup operations require the vnode.
728 */
729 VOP_UNLOCK(imgp->vp);
730
731 if (disallow_high_osrel &&
732 P_OSREL_MAJOR(p->p_osrel) > P_OSREL_MAJOR(__FreeBSD_version)) {
733 error = ENOEXEC;
734 uprintf("Osrel %d for image %s too high\n", p->p_osrel,
735 imgp->execpath != NULL ? imgp->execpath : "<unresolved>");
736 vn_lock(imgp->vp, LK_SHARED | LK_RETRY);
737 goto exec_fail_dealloc;
738 }
739
740 /*
741 * Copy out strings (args and env) and initialize stack base.
742 */
743 error = (*p->p_sysent->sv_copyout_strings)(imgp, &stack_base);
744 if (error != 0) {
745 vn_lock(imgp->vp, LK_SHARED | LK_RETRY);
746 goto exec_fail_dealloc;
747 }
748
749 /*
750 * Stack setup.
751 */
752 error = (*p->p_sysent->sv_fixup)(&stack_base, imgp);
753 if (error != 0) {
754 vn_lock(imgp->vp, LK_SHARED | LK_RETRY);
755 goto exec_fail_dealloc;
756 }
757
758 /*
759 * For security and other reasons, the file descriptor table cannot be
760 * shared after an exec.
761 */
762 fdunshare(td);
763 pdunshare(td);
764 /* close files on exec */
765 fdcloseexec(td);
766
767 /*
768 * Malloc things before we need locks.
769 */
770 i = exec_args_get_begin_envv(imgp->args) - imgp->args->begin_argv;
771 /* Cache arguments if they fit inside our allowance */
772 if (ps_arg_cache_limit >= i + sizeof(struct pargs)) {
773 newargs = pargs_alloc(i);
774 bcopy(imgp->args->begin_argv, newargs->ar_args, i);
775 }
776
777 /*
778 * For security and other reasons, signal handlers cannot
779 * be shared after an exec. The new process gets a copy of the old
780 * handlers. In execsigs(), the new process will have its signals
781 * reset.
782 */
783 if (sigacts_shared(p->p_sigacts)) {
784 oldsigacts = p->p_sigacts;
785 newsigacts = sigacts_alloc();
786 sigacts_copy(newsigacts, oldsigacts);
787 }
788
789 vn_lock(imgp->vp, LK_SHARED | LK_RETRY);
790
791 PROC_LOCK(p);
792 if (oldsigacts)
793 p->p_sigacts = newsigacts;
794 /* Stop profiling */
795 stopprofclock(p);
796
797 /* reset caught signals */
798 execsigs(p);
799
800 /* name this process - nameiexec(p, ndp) */
801 bzero(p->p_comm, sizeof(p->p_comm));
802 if (args->fname)
803 bcopy(nd.ni_cnd.cn_nameptr, p->p_comm,
804 min(nd.ni_cnd.cn_namelen, MAXCOMLEN));
805 else if (vn_commname(newtextvp, p->p_comm, sizeof(p->p_comm)) != 0)
806 bcopy(fexecv_proc_title, p->p_comm, sizeof(fexecv_proc_title));
807 bcopy(p->p_comm, td->td_name, sizeof(td->td_name));
808 #ifdef KTR
809 sched_clear_tdname(td);
810 #endif
811
812 /*
813 * mark as execed, wakeup the process that vforked (if any) and tell
814 * it that it now has its own resources back
815 */
816 p->p_flag |= P_EXEC;
817 td->td_pflags2 &= ~TDP2_UEXTERR;
818 if ((p->p_flag2 & P2_NOTRACE_EXEC) == 0)
819 p->p_flag2 &= ~P2_NOTRACE;
820 if ((p->p_flag2 & P2_STKGAP_DISABLE_EXEC) == 0)
821 p->p_flag2 &= ~P2_STKGAP_DISABLE;
822 p->p_flag2 &= ~(P2_MEMBAR_PRIVE | P2_MEMBAR_PRIVE_SYNCORE |
823 P2_MEMBAR_GLOBE);
824 if (p->p_flag & P_PPWAIT) {
825 p->p_flag &= ~(P_PPWAIT | P_PPTRACE);
826 cv_broadcast(&p->p_pwait);
827 /* STOPs are no longer ignored, arrange for AST */
828 signotify(td);
829 }
830
831 if ((imgp->sysent->sv_setid_allowed != NULL &&
832 !(*imgp->sysent->sv_setid_allowed)(td, imgp)) ||
833 (p->p_flag2 & P2_NO_NEW_PRIVS) != 0)
834 execve_nosetid(imgp);
835
836 /*
837 * Implement image setuid/setgid installation.
838 */
839 if (imgp->credential_setid) {
840 /*
841 * Turn off syscall tracing for set-id programs, except for
842 * root. Record any set-id flags first to make sure that
843 * we do not regain any tracing during a possible block.
844 */
845 setsugid(p);
846 #ifdef KTRACE
847 kiop = ktrprocexec(p);
848 #endif
849 /*
850 * Close any file descriptors 0..2 that reference procfs,
851 * then make sure file descriptors 0..2 are in use.
852 *
853 * Both fdsetugidsafety() and fdcheckstd() may call functions
854 * taking sleepable locks, so temporarily drop our locks.
855 */
856 PROC_UNLOCK(p);
857 VOP_UNLOCK(imgp->vp);
858 fdsetugidsafety(td);
859 error = fdcheckstd(td);
860 vn_lock(imgp->vp, LK_SHARED | LK_RETRY);
861 if (error != 0)
862 goto exec_fail_dealloc;
863 PROC_LOCK(p);
864 #ifdef MAC
865 if (will_transition) {
866 mac_vnode_execve_transition(oldcred, imgp->newcred,
867 imgp->vp, interpvplabel, imgp);
868 }
869 #endif
870 } else {
871 if (oldcred->cr_uid == oldcred->cr_ruid &&
872 oldcred->cr_gid == oldcred->cr_rgid)
873 p->p_flag &= ~P_SUGID;
874 }
875 /*
876 * Set the new credentials.
877 */
878 if (imgp->newcred != NULL) {
879 proc_set_cred(p, imgp->newcred);
880 crfree(oldcred);
881 oldcred = NULL;
882 }
883
884 /*
885 * Store the vp for use in kern.proc.pathname. This vnode was
886 * referenced by namei() or by fexecve variant of fname handling.
887 */
888 oldtextvp = p->p_textvp;
889 p->p_textvp = newtextvp;
890 oldtextdvp = p->p_textdvp;
891 p->p_textdvp = newtextdvp;
892 newtextdvp = NULL;
893 oldbinname = p->p_binname;
894 p->p_binname = newbinname;
895 newbinname = NULL;
896
897 #ifdef KDTRACE_HOOKS
898 /*
899 * Tell the DTrace fasttrap provider about the exec if it
900 * has declared an interest.
901 */
902 if (dtrace_fasttrap_exec)
903 dtrace_fasttrap_exec(p);
904 #endif
905
906 /*
907 * Notify others that we exec'd, and clear the P_INEXEC flag
908 * as we're now a bona fide freshly-execed process.
909 */
910 KNOTE_LOCKED(p->p_klist, NOTE_EXEC);
911 p->p_flag &= ~P_INEXEC;
912
913 /* clear "fork but no exec" flag, as we _are_ execing */
914 p->p_acflag &= ~AFORK;
915
916 /*
917 * Free any previous argument cache and replace it with
918 * the new argument cache, if any.
919 */
920 oldargs = p->p_args;
921 p->p_args = newargs;
922 newargs = NULL;
923
924 PROC_UNLOCK(p);
925
926 #ifdef HWPMC_HOOKS
927 /*
928 * Check if system-wide sampling is in effect or if the
929 * current process is using PMCs. If so, do exec() time
930 * processing. This processing needs to happen AFTER the
931 * P_INEXEC flag is cleared.
932 */
933 if (PMC_SYSTEM_SAMPLING_ACTIVE() || PMC_PROC_IS_USING_PMCS(p)) {
934 VOP_UNLOCK(imgp->vp);
935 pe.pm_credentialschanged = credential_changing;
936 pe.pm_baseaddr = imgp->reloc_base;
937 pe.pm_dynaddr = imgp->et_dyn_addr;
938
939 PMC_CALL_HOOK_X(td, PMC_FN_PROCESS_EXEC, (void *) &pe);
940 vn_lock(imgp->vp, LK_SHARED | LK_RETRY);
941 }
942 #endif
943
944 #ifdef HWT_HOOKS
945 if ((td->td_proc->p_flag2 & P2_HWT) != 0) {
946 struct hwt_record_entry ent;
947
948 VOP_UNLOCK(imgp->vp);
949 ent.fullpath = imgp->execpath;
950 ent.addr = imgp->et_dyn_addr;
951 ent.baseaddr = imgp->reloc_base;
952 ent.record_type = HWT_RECORD_EXECUTABLE;
953 HWT_CALL_HOOK(td, HWT_EXEC, &ent);
954 vn_lock(imgp->vp, LK_SHARED | LK_RETRY);
955 }
956 #endif
957
958 /* Set values passed into the program in registers. */
959 (*p->p_sysent->sv_setregs)(td, imgp, stack_base);
960
961 VOP_MMAPPED(imgp->vp);
962
963 SDT_PROBE1(proc, , , exec__success, args->fname);
964
965 exec_fail_dealloc:
966 if (error != 0) {
967 p->p_osrel = orig_osrel;
968 p->p_fctl0 = orig_fctl0;
969 p->p_elf_brandinfo = orig_brandinfo;
970 }
971
972 if (imgp->firstpage != NULL)
973 exec_unmap_first_page(imgp);
974
975 if (imgp->vp != NULL) {
976 if (imgp->opened)
977 VOP_CLOSE(imgp->vp, FREAD, td->td_ucred, td);
978 if (imgp->textset)
979 VOP_UNSET_TEXT_CHECKED(imgp->vp);
980 if (error != 0)
981 vput(imgp->vp);
982 else
983 VOP_UNLOCK(imgp->vp);
984 if (args->fname != NULL)
985 NDFREE_PNBUF(&nd);
986 if (newtextdvp != NULL)
987 vrele(newtextdvp);
988 free(newbinname, M_PARGS);
989 }
990
991 if (imgp->object != NULL)
992 vm_object_deallocate(imgp->object);
993
994 free(imgp->freepath, M_TEMP);
995
996 if (error == 0) {
997 if (p->p_ptevents & PTRACE_EXEC) {
998 PROC_LOCK(p);
999 if (p->p_ptevents & PTRACE_EXEC)
1000 td->td_dbgflags |= TDB_EXEC;
1001 PROC_UNLOCK(p);
1002 }
1003 } else {
1004 exec_fail:
1005 /* we're done here, clear P_INEXEC */
1006 PROC_LOCK(p);
1007 p->p_flag &= ~P_INEXEC;
1008 PROC_UNLOCK(p);
1009
1010 SDT_PROBE1(proc, , , exec__failure, error);
1011 }
1012
1013 if (imgp->newcred != NULL && oldcred != NULL)
1014 crfree(imgp->newcred);
1015
1016 #ifdef MAC
1017 mac_execve_exit(imgp);
1018 mac_execve_interpreter_exit(interpvplabel);
1019 #endif
1020 exec_free_args(args);
1021
1022 /*
1023 * Handle deferred decrement of ref counts.
1024 */
1025 if (oldtextvp != NULL)
1026 vrele(oldtextvp);
1027 if (oldtextdvp != NULL)
1028 vrele(oldtextdvp);
1029 free(oldbinname, M_PARGS);
1030 #ifdef KTRACE
1031 ktr_io_params_free(kiop);
1032 #endif
1033 pargs_drop(oldargs);
1034 pargs_drop(newargs);
1035 if (oldsigacts != NULL)
1036 sigacts_free(oldsigacts);
1037 if (euip != NULL)
1038 uifree(euip);
1039
1040 if (error && imgp->vmspace_destroyed) {
1041 /* sorry, no more process anymore. exit gracefully */
1042 exec_cleanup(td, oldvmspace);
1043 exit1(td, 0, SIGABRT);
1044 /* NOT REACHED */
1045 }
1046
1047 #ifdef KTRACE
1048 if (error == 0)
1049 ktrprocctor(p);
1050 #endif
1051
1052 /*
1053 * We don't want cpu_set_syscall_retval() to overwrite any of
1054 * the register values put in place by exec_setregs().
1055 * Implementations of cpu_set_syscall_retval() will leave
1056 * registers unmodified when returning EJUSTRETURN.
1057 */
1058 return (error == 0 ? EJUSTRETURN : error);
1059 }
1060
1061 void
exec_cleanup(struct thread * td,struct vmspace * oldvmspace)1062 exec_cleanup(struct thread *td, struct vmspace *oldvmspace)
1063 {
1064 if ((td->td_pflags & TDP_EXECVMSPC) != 0) {
1065 KASSERT(td->td_proc->p_vmspace != oldvmspace,
1066 ("oldvmspace still used"));
1067 vmspace_free(oldvmspace);
1068 td->td_pflags &= ~TDP_EXECVMSPC;
1069 }
1070 }
1071
1072 int
exec_map_first_page(struct image_params * imgp)1073 exec_map_first_page(struct image_params *imgp)
1074 {
1075 vm_object_t object;
1076 vm_page_t m;
1077 int error;
1078
1079 if (imgp->firstpage != NULL)
1080 exec_unmap_first_page(imgp);
1081
1082 object = imgp->vp->v_object;
1083 if (object == NULL)
1084 return (EACCES);
1085 #if VM_NRESERVLEVEL > 0
1086 if ((object->flags & OBJ_COLORED) == 0) {
1087 VM_OBJECT_WLOCK(object);
1088 vm_object_color(object, 0);
1089 VM_OBJECT_WUNLOCK(object);
1090 }
1091 #endif
1092 error = vm_page_grab_valid_unlocked(&m, object, 0,
1093 VM_ALLOC_COUNT(VM_INITIAL_PAGEIN) |
1094 VM_ALLOC_NORMAL | VM_ALLOC_NOBUSY | VM_ALLOC_WIRED);
1095
1096 if (error != VM_PAGER_OK)
1097 return (EIO);
1098 imgp->firstpage = sf_buf_alloc(m, 0);
1099 imgp->image_header = (char *)sf_buf_kva(imgp->firstpage);
1100
1101 return (0);
1102 }
1103
1104 void
exec_unmap_first_page(struct image_params * imgp)1105 exec_unmap_first_page(struct image_params *imgp)
1106 {
1107 vm_page_t m;
1108
1109 if (imgp->firstpage != NULL) {
1110 m = sf_buf_page(imgp->firstpage);
1111 sf_buf_free(imgp->firstpage);
1112 imgp->firstpage = NULL;
1113 vm_page_unwire(m, PQ_ACTIVE);
1114 }
1115 }
1116
1117 void
exec_onexec_old(struct thread * td)1118 exec_onexec_old(struct thread *td)
1119 {
1120 sigfastblock_clear(td);
1121 umtx_exec(td->td_proc);
1122 }
1123
1124 /*
1125 * This is an optimization which removes the unmanaged shared page
1126 * mapping. In combination with pmap_remove_pages(), which cleans all
1127 * managed mappings in the process' vmspace pmap, no work will be left
1128 * for pmap_remove(min, max).
1129 */
1130 void
exec_free_abi_mappings(struct proc * p)1131 exec_free_abi_mappings(struct proc *p)
1132 {
1133 struct vmspace *vmspace;
1134
1135 vmspace = p->p_vmspace;
1136 if (refcount_load(&vmspace->vm_refcnt) != 1)
1137 return;
1138
1139 if (!PROC_HAS_SHP(p))
1140 return;
1141
1142 pmap_remove(vmspace_pmap(vmspace), vmspace->vm_shp_base,
1143 vmspace->vm_shp_base + p->p_sysent->sv_shared_page_len);
1144 }
1145
1146 /*
1147 * Run down the current address space and install a new one.
1148 */
1149 int
exec_new_vmspace(struct image_params * imgp,struct sysentvec * sv)1150 exec_new_vmspace(struct image_params *imgp, struct sysentvec *sv)
1151 {
1152 int error;
1153 struct proc *p = imgp->proc;
1154 struct vmspace *vmspace = p->p_vmspace;
1155 struct thread *td = curthread;
1156 vm_offset_t sv_minuser;
1157 vm_map_t map;
1158
1159 imgp->vmspace_destroyed = true;
1160 imgp->sysent = sv;
1161
1162 if (p->p_sysent->sv_onexec_old != NULL)
1163 p->p_sysent->sv_onexec_old(td);
1164 itimers_exec(p);
1165
1166 EVENTHANDLER_DIRECT_INVOKE(process_exec, p, imgp);
1167
1168 /*
1169 * Blow away entire process VM, if address space not shared,
1170 * otherwise, create a new VM space so that other threads are
1171 * not disrupted
1172 */
1173 map = &vmspace->vm_map;
1174 if (map_at_zero)
1175 sv_minuser = sv->sv_minuser;
1176 else
1177 sv_minuser = MAX(sv->sv_minuser, PAGE_SIZE);
1178 if (refcount_load(&vmspace->vm_refcnt) == 1 &&
1179 vm_map_min(map) == sv_minuser &&
1180 vm_map_max(map) == sv->sv_maxuser &&
1181 cpu_exec_vmspace_reuse(p, map)) {
1182 exec_free_abi_mappings(p);
1183 shmexit(vmspace);
1184 pmap_remove_pages(vmspace_pmap(vmspace));
1185 vm_map_remove(map, vm_map_min(map), vm_map_max(map));
1186 /*
1187 * An exec terminates mlockall(MCL_FUTURE).
1188 * ASLR and W^X states must be re-evaluated.
1189 */
1190 vm_map_lock(map);
1191 vm_map_modflags(map, 0, MAP_WIREFUTURE | MAP_ASLR |
1192 MAP_ASLR_IGNSTART | MAP_ASLR_STACK | MAP_WXORX);
1193 vm_map_unlock(map);
1194 } else {
1195 error = vmspace_exec(p, sv_minuser, sv->sv_maxuser);
1196 if (error)
1197 return (error);
1198 vmspace = p->p_vmspace;
1199 map = &vmspace->vm_map;
1200 }
1201 map->flags |= imgp->map_flags;
1202
1203 return (sv->sv_onexec != NULL ? sv->sv_onexec(p, imgp) : 0);
1204 }
1205
1206 /*
1207 * Compute the stack size limit and map the main process stack.
1208 * Map the shared page.
1209 */
1210 int
exec_map_stack(struct image_params * imgp)1211 exec_map_stack(struct image_params *imgp)
1212 {
1213 struct rlimit rlim_stack;
1214 struct sysentvec *sv;
1215 struct proc *p;
1216 vm_map_t map;
1217 struct vmspace *vmspace;
1218 vm_offset_t stack_addr, stack_top;
1219 vm_offset_t sharedpage_addr;
1220 u_long ssiz;
1221 int error, find_space, stack_off;
1222 vm_prot_t stack_prot;
1223 vm_object_t obj;
1224
1225 p = imgp->proc;
1226 sv = p->p_sysent;
1227
1228 if (imgp->stack_sz != 0) {
1229 ssiz = trunc_page(imgp->stack_sz);
1230 PROC_LOCK(p);
1231 lim_rlimit_proc(p, RLIMIT_STACK, &rlim_stack);
1232 PROC_UNLOCK(p);
1233 if (ssiz > rlim_stack.rlim_max)
1234 ssiz = rlim_stack.rlim_max;
1235 if (ssiz > rlim_stack.rlim_cur) {
1236 rlim_stack.rlim_cur = ssiz;
1237 kern_setrlimit(curthread, RLIMIT_STACK, &rlim_stack);
1238 }
1239 } else if (sv->sv_maxssiz != NULL) {
1240 ssiz = *sv->sv_maxssiz;
1241 } else {
1242 ssiz = maxssiz;
1243 }
1244
1245 vmspace = p->p_vmspace;
1246 map = &vmspace->vm_map;
1247
1248 stack_prot = sv->sv_shared_page_obj != NULL && imgp->stack_prot != 0 ?
1249 imgp->stack_prot : sv->sv_stackprot;
1250 if ((map->flags & MAP_ASLR_STACK) != 0) {
1251 stack_addr = round_page((vm_offset_t)p->p_vmspace->vm_daddr +
1252 lim_max(curthread, RLIMIT_DATA));
1253 find_space = VMFS_ANY_SPACE;
1254 } else {
1255 stack_addr = sv->sv_usrstack - ssiz;
1256 find_space = VMFS_NO_SPACE;
1257 }
1258 error = vm_map_find(map, NULL, 0, &stack_addr, (vm_size_t)ssiz,
1259 sv->sv_usrstack, find_space, stack_prot, VM_PROT_ALL,
1260 MAP_STACK_AREA);
1261 if (error != KERN_SUCCESS) {
1262 uprintf("exec_new_vmspace: mapping stack size %#jx prot %#x "
1263 "failed, mach error %d errno %d\n", (uintmax_t)ssiz,
1264 stack_prot, error, vm_mmap_to_errno(error));
1265 return (vm_mmap_to_errno(error));
1266 }
1267
1268 stack_top = stack_addr + ssiz;
1269 if ((map->flags & MAP_ASLR_STACK) != 0) {
1270 /* Randomize within the first page of the stack. */
1271 arc4rand(&stack_off, sizeof(stack_off), 0);
1272 stack_top -= rounddown2(stack_off & PAGE_MASK, sizeof(void *));
1273 }
1274
1275 /* Map a shared page */
1276 obj = sv->sv_shared_page_obj;
1277 if (obj == NULL) {
1278 sharedpage_addr = 0;
1279 goto out;
1280 }
1281
1282 /*
1283 * If randomization is disabled then the shared page will
1284 * be mapped at address specified in sysentvec.
1285 * Otherwise any address above .data section can be selected.
1286 * Same logic is used for stack address randomization.
1287 * If the address randomization is applied map a guard page
1288 * at the top of UVA.
1289 */
1290 vm_object_reference(obj);
1291 if ((imgp->imgp_flags & IMGP_ASLR_SHARED_PAGE) != 0) {
1292 sharedpage_addr = round_page((vm_offset_t)p->p_vmspace->vm_daddr +
1293 lim_max(curthread, RLIMIT_DATA));
1294
1295 error = vm_map_fixed(map, NULL, 0,
1296 sv->sv_maxuser - PAGE_SIZE, PAGE_SIZE,
1297 VM_PROT_NONE, VM_PROT_NONE, MAP_CREATE_GUARD);
1298 if (error != KERN_SUCCESS) {
1299 /*
1300 * This is not fatal, so let's just print a warning
1301 * and continue.
1302 */
1303 uprintf("%s: Mapping guard page at the top of UVA failed"
1304 " mach error %d errno %d",
1305 __func__, error, vm_mmap_to_errno(error));
1306 }
1307
1308 error = vm_map_find(map, obj, 0,
1309 &sharedpage_addr, sv->sv_shared_page_len,
1310 sv->sv_maxuser, VMFS_ANY_SPACE,
1311 VM_PROT_READ | VM_PROT_EXECUTE,
1312 VM_PROT_READ | VM_PROT_EXECUTE,
1313 MAP_INHERIT_SHARE | MAP_ACC_NO_CHARGE);
1314 } else {
1315 sharedpage_addr = sv->sv_shared_page_base;
1316 vm_map_fixed(map, obj, 0,
1317 sharedpage_addr, sv->sv_shared_page_len,
1318 VM_PROT_READ | VM_PROT_EXECUTE,
1319 VM_PROT_READ | VM_PROT_EXECUTE,
1320 MAP_INHERIT_SHARE | MAP_ACC_NO_CHARGE);
1321 }
1322 if (error != KERN_SUCCESS) {
1323 uprintf("%s: mapping shared page at addr: %p"
1324 "failed, mach error %d errno %d\n", __func__,
1325 (void *)sharedpage_addr, error, vm_mmap_to_errno(error));
1326 vm_object_deallocate(obj);
1327 return (vm_mmap_to_errno(error));
1328 }
1329 out:
1330 /*
1331 * vm_ssize and vm_maxsaddr are somewhat antiquated concepts, but they
1332 * are still used to enforce the stack rlimit on the process stack.
1333 */
1334 vmspace->vm_maxsaddr = (char *)stack_addr;
1335 vmspace->vm_stacktop = stack_top;
1336 vmspace->vm_ssize = sgrowsiz >> PAGE_SHIFT;
1337 vmspace->vm_shp_base = sharedpage_addr;
1338
1339 return (0);
1340 }
1341
1342 /*
1343 * Copy out argument and environment strings from the old process address
1344 * space into the temporary string buffer.
1345 */
1346 int
exec_copyin_args(struct image_args * args,const char * fname,char ** argv,char ** envv)1347 exec_copyin_args(struct image_args *args, const char *fname,
1348 char **argv, char **envv)
1349 {
1350 u_long arg, env;
1351 int error;
1352
1353 bzero(args, sizeof(*args));
1354 if (argv == NULL)
1355 return (EFAULT);
1356
1357 /*
1358 * Allocate demand-paged memory for the file name, argument, and
1359 * environment strings.
1360 */
1361 error = exec_alloc_args(args);
1362 if (error != 0)
1363 return (error);
1364
1365 /*
1366 * Copy the file name.
1367 */
1368 error = exec_args_add_fname(args, fname, UIO_USERSPACE);
1369 if (error != 0)
1370 goto err_exit;
1371
1372 /*
1373 * extract arguments first
1374 */
1375 for (;;) {
1376 error = fueword(argv++, &arg);
1377 if (error == -1) {
1378 error = EFAULT;
1379 goto err_exit;
1380 }
1381 if (arg == 0)
1382 break;
1383 error = exec_args_add_arg(args, (char *)(uintptr_t)arg,
1384 UIO_USERSPACE);
1385 if (error != 0)
1386 goto err_exit;
1387 }
1388
1389 /*
1390 * extract environment strings
1391 */
1392 if (envv) {
1393 for (;;) {
1394 error = fueword(envv++, &env);
1395 if (error == -1) {
1396 error = EFAULT;
1397 goto err_exit;
1398 }
1399 if (env == 0)
1400 break;
1401 error = exec_args_add_env(args,
1402 (char *)(uintptr_t)env, UIO_USERSPACE);
1403 if (error != 0)
1404 goto err_exit;
1405 }
1406 }
1407
1408 return (0);
1409
1410 err_exit:
1411 exec_free_args(args);
1412 return (error);
1413 }
1414
1415 struct exec_args_kva {
1416 vm_offset_t addr;
1417 u_int gen;
1418 SLIST_ENTRY(exec_args_kva) next;
1419 };
1420
1421 DPCPU_DEFINE_STATIC(struct exec_args_kva *, exec_args_kva);
1422
1423 static SLIST_HEAD(, exec_args_kva) exec_args_kva_freelist;
1424 static struct mtx exec_args_kva_mtx;
1425 static u_int exec_args_gen;
1426
1427 static void
exec_prealloc_args_kva(void * arg __unused)1428 exec_prealloc_args_kva(void *arg __unused)
1429 {
1430 struct exec_args_kva *argkva;
1431 u_int i;
1432
1433 SLIST_INIT(&exec_args_kva_freelist);
1434 mtx_init(&exec_args_kva_mtx, "exec args kva", NULL, MTX_DEF);
1435 for (i = 0; i < exec_map_entries; i++) {
1436 argkva = malloc(sizeof(*argkva), M_PARGS, M_WAITOK);
1437 argkva->addr = kmap_alloc_wait(exec_map, exec_map_entry_size);
1438 argkva->gen = exec_args_gen;
1439 SLIST_INSERT_HEAD(&exec_args_kva_freelist, argkva, next);
1440 }
1441 }
1442 SYSINIT(exec_args_kva, SI_SUB_EXEC, SI_ORDER_ANY, exec_prealloc_args_kva, NULL);
1443
1444 static vm_offset_t
exec_alloc_args_kva(void ** cookie)1445 exec_alloc_args_kva(void **cookie)
1446 {
1447 struct exec_args_kva *argkva;
1448
1449 argkva = (void *)atomic_readandclear_ptr(
1450 (uintptr_t *)DPCPU_PTR(exec_args_kva));
1451 if (argkva == NULL) {
1452 mtx_lock(&exec_args_kva_mtx);
1453 while ((argkva = SLIST_FIRST(&exec_args_kva_freelist)) == NULL)
1454 (void)mtx_sleep(&exec_args_kva_freelist,
1455 &exec_args_kva_mtx, 0, "execkva", 0);
1456 SLIST_REMOVE_HEAD(&exec_args_kva_freelist, next);
1457 mtx_unlock(&exec_args_kva_mtx);
1458 }
1459 kasan_mark((void *)argkva->addr, exec_map_entry_size,
1460 exec_map_entry_size, 0);
1461 *(struct exec_args_kva **)cookie = argkva;
1462 return (argkva->addr);
1463 }
1464
1465 static void
exec_release_args_kva(struct exec_args_kva * argkva,u_int gen)1466 exec_release_args_kva(struct exec_args_kva *argkva, u_int gen)
1467 {
1468 vm_offset_t base;
1469
1470 base = argkva->addr;
1471 kasan_mark((void *)argkva->addr, 0, exec_map_entry_size,
1472 KASAN_EXEC_ARGS_FREED);
1473 if (argkva->gen != gen) {
1474 (void)vm_map_madvise(exec_map, base, base + exec_map_entry_size,
1475 MADV_FREE);
1476 argkva->gen = gen;
1477 }
1478 if (!atomic_cmpset_ptr((uintptr_t *)DPCPU_PTR(exec_args_kva),
1479 (uintptr_t)NULL, (uintptr_t)argkva)) {
1480 mtx_lock(&exec_args_kva_mtx);
1481 SLIST_INSERT_HEAD(&exec_args_kva_freelist, argkva, next);
1482 wakeup_one(&exec_args_kva_freelist);
1483 mtx_unlock(&exec_args_kva_mtx);
1484 }
1485 }
1486
1487 static void
exec_free_args_kva(void * cookie)1488 exec_free_args_kva(void *cookie)
1489 {
1490
1491 exec_release_args_kva(cookie, exec_args_gen);
1492 }
1493
1494 static void
exec_args_kva_lowmem(void * arg __unused,int flags __unused)1495 exec_args_kva_lowmem(void *arg __unused, int flags __unused)
1496 {
1497 SLIST_HEAD(, exec_args_kva) head;
1498 struct exec_args_kva *argkva;
1499 u_int gen;
1500 int i;
1501
1502 gen = atomic_fetchadd_int(&exec_args_gen, 1) + 1;
1503
1504 /*
1505 * Force an madvise of each KVA range. Any currently allocated ranges
1506 * will have MADV_FREE applied once they are freed.
1507 */
1508 SLIST_INIT(&head);
1509 mtx_lock(&exec_args_kva_mtx);
1510 SLIST_SWAP(&head, &exec_args_kva_freelist, exec_args_kva);
1511 mtx_unlock(&exec_args_kva_mtx);
1512 while ((argkva = SLIST_FIRST(&head)) != NULL) {
1513 SLIST_REMOVE_HEAD(&head, next);
1514 exec_release_args_kva(argkva, gen);
1515 }
1516
1517 CPU_FOREACH(i) {
1518 argkva = (void *)atomic_readandclear_ptr(
1519 (uintptr_t *)DPCPU_ID_PTR(i, exec_args_kva));
1520 if (argkva != NULL)
1521 exec_release_args_kva(argkva, gen);
1522 }
1523 }
1524 EVENTHANDLER_DEFINE(vm_lowmem, exec_args_kva_lowmem, NULL,
1525 EVENTHANDLER_PRI_ANY);
1526
1527 /*
1528 * Allocate temporary demand-paged, zero-filled memory for the file name,
1529 * argument, and environment strings.
1530 */
1531 int
exec_alloc_args(struct image_args * args)1532 exec_alloc_args(struct image_args *args)
1533 {
1534
1535 args->buf = (char *)exec_alloc_args_kva(&args->bufkva);
1536 return (0);
1537 }
1538
1539 void
exec_free_args(struct image_args * args)1540 exec_free_args(struct image_args *args)
1541 {
1542
1543 if (args->buf != NULL) {
1544 exec_free_args_kva(args->bufkva);
1545 args->buf = NULL;
1546 }
1547 if (args->fname_buf != NULL) {
1548 free(args->fname_buf, M_TEMP);
1549 args->fname_buf = NULL;
1550 }
1551 }
1552
1553 /*
1554 * A set to functions to fill struct image args.
1555 *
1556 * NOTE: exec_args_add_fname() must be called (possibly with a NULL
1557 * fname) before the other functions. All exec_args_add_arg() calls must
1558 * be made before any exec_args_add_env() calls. exec_args_adjust_args()
1559 * may be called any time after exec_args_add_fname().
1560 *
1561 * exec_args_add_fname() - install path to be executed
1562 * exec_args_add_arg() - append an argument string
1563 * exec_args_add_env() - append an env string
1564 * exec_args_adjust_args() - adjust location of the argument list to
1565 * allow new arguments to be prepended
1566 */
1567 int
exec_args_add_fname(struct image_args * args,const char * fname,enum uio_seg segflg)1568 exec_args_add_fname(struct image_args *args, const char *fname,
1569 enum uio_seg segflg)
1570 {
1571 int error;
1572 size_t length;
1573
1574 KASSERT(args->fname == NULL, ("fname already appended"));
1575 KASSERT(args->endp == NULL, ("already appending to args"));
1576
1577 if (fname != NULL) {
1578 args->fname = args->buf;
1579 error = segflg == UIO_SYSSPACE ?
1580 copystr(fname, args->fname, PATH_MAX, &length) :
1581 copyinstr(fname, args->fname, PATH_MAX, &length);
1582 if (error != 0)
1583 return (error == ENAMETOOLONG ? E2BIG : error);
1584 } else
1585 length = 0;
1586
1587 /* Set up for _arg_*()/_env_*() */
1588 args->endp = args->buf + length;
1589 /* begin_argv must be set and kept updated */
1590 args->begin_argv = args->endp;
1591 KASSERT(exec_map_entry_size - length >= ARG_MAX,
1592 ("too little space remaining for arguments %zu < %zu",
1593 exec_map_entry_size - length, (size_t)ARG_MAX));
1594 args->stringspace = ARG_MAX;
1595
1596 return (0);
1597 }
1598
1599 static int
exec_args_add_str(struct image_args * args,const char * str,enum uio_seg segflg,int * countp)1600 exec_args_add_str(struct image_args *args, const char *str,
1601 enum uio_seg segflg, int *countp)
1602 {
1603 int error;
1604 size_t length;
1605
1606 KASSERT(args->endp != NULL, ("endp not initialized"));
1607 KASSERT(args->begin_argv != NULL, ("begin_argp not initialized"));
1608
1609 error = (segflg == UIO_SYSSPACE) ?
1610 copystr(str, args->endp, args->stringspace, &length) :
1611 copyinstr(str, args->endp, args->stringspace, &length);
1612 if (error != 0)
1613 return (error == ENAMETOOLONG ? E2BIG : error);
1614 args->stringspace -= length;
1615 args->endp += length;
1616 (*countp)++;
1617
1618 return (0);
1619 }
1620
1621 int
exec_args_add_arg(struct image_args * args,const char * argp,enum uio_seg segflg)1622 exec_args_add_arg(struct image_args *args, const char *argp,
1623 enum uio_seg segflg)
1624 {
1625
1626 KASSERT(args->envc == 0, ("appending args after env"));
1627
1628 return (exec_args_add_str(args, argp, segflg, &args->argc));
1629 }
1630
1631 int
exec_args_add_env(struct image_args * args,const char * envp,enum uio_seg segflg)1632 exec_args_add_env(struct image_args *args, const char *envp,
1633 enum uio_seg segflg)
1634 {
1635
1636 if (args->envc == 0)
1637 args->begin_envv = args->endp;
1638
1639 return (exec_args_add_str(args, envp, segflg, &args->envc));
1640 }
1641
1642 int
exec_args_adjust_args(struct image_args * args,size_t consume,ssize_t extend)1643 exec_args_adjust_args(struct image_args *args, size_t consume, ssize_t extend)
1644 {
1645 ssize_t offset;
1646
1647 KASSERT(args->endp != NULL, ("endp not initialized"));
1648 KASSERT(args->begin_argv != NULL, ("begin_argp not initialized"));
1649
1650 offset = extend - consume;
1651 if (args->stringspace < offset)
1652 return (E2BIG);
1653 memmove(args->begin_argv + extend, args->begin_argv + consume,
1654 args->endp - args->begin_argv + consume);
1655 if (args->envc > 0)
1656 args->begin_envv += offset;
1657 args->endp += offset;
1658 args->stringspace -= offset;
1659 return (0);
1660 }
1661
1662 char *
exec_args_get_begin_envv(struct image_args * args)1663 exec_args_get_begin_envv(struct image_args *args)
1664 {
1665
1666 KASSERT(args->endp != NULL, ("endp not initialized"));
1667
1668 if (args->envc > 0)
1669 return (args->begin_envv);
1670 return (args->endp);
1671 }
1672
1673 /*
1674 * Copy strings out to the new process address space, constructing new arg
1675 * and env vector tables. Return a pointer to the base so that it can be used
1676 * as the initial stack pointer.
1677 */
1678 int
exec_copyout_strings(struct image_params * imgp,uintptr_t * stack_base)1679 exec_copyout_strings(struct image_params *imgp, uintptr_t *stack_base)
1680 {
1681 int argc, envc;
1682 char **vectp;
1683 char *stringp;
1684 uintptr_t destp, ustringp;
1685 struct ps_strings *arginfo;
1686 struct proc *p;
1687 struct sysentvec *sysent;
1688 size_t execpath_len;
1689 int error, szsigcode;
1690 char canary[sizeof(long) * 8];
1691
1692 p = imgp->proc;
1693 sysent = p->p_sysent;
1694
1695 destp = PROC_PS_STRINGS(p);
1696 arginfo = imgp->ps_strings = (void *)destp;
1697
1698 /*
1699 * Install sigcode.
1700 */
1701 if (sysent->sv_shared_page_base == 0 && sysent->sv_szsigcode != NULL) {
1702 szsigcode = *(sysent->sv_szsigcode);
1703 destp -= szsigcode;
1704 destp = rounddown2(destp, sizeof(void *));
1705 error = copyout(sysent->sv_sigcode, (void *)destp, szsigcode);
1706 if (error != 0)
1707 return (error);
1708 }
1709
1710 /*
1711 * Copy the image path for the rtld.
1712 */
1713 if (imgp->execpath != NULL && imgp->auxargs != NULL) {
1714 execpath_len = strlen(imgp->execpath) + 1;
1715 destp -= execpath_len;
1716 destp = rounddown2(destp, sizeof(void *));
1717 imgp->execpathp = (void *)destp;
1718 error = copyout(imgp->execpath, imgp->execpathp, execpath_len);
1719 if (error != 0)
1720 return (error);
1721 }
1722
1723 /*
1724 * Prepare the canary for SSP.
1725 */
1726 arc4rand(canary, sizeof(canary), 0);
1727 destp -= sizeof(canary);
1728 imgp->canary = (void *)destp;
1729 error = copyout(canary, imgp->canary, sizeof(canary));
1730 if (error != 0)
1731 return (error);
1732 imgp->canarylen = sizeof(canary);
1733
1734 /*
1735 * Prepare the pagesizes array.
1736 */
1737 imgp->pagesizeslen = sizeof(pagesizes[0]) * MAXPAGESIZES;
1738 destp -= imgp->pagesizeslen;
1739 destp = rounddown2(destp, sizeof(void *));
1740 imgp->pagesizes = (void *)destp;
1741 error = copyout(pagesizes, imgp->pagesizes, imgp->pagesizeslen);
1742 if (error != 0)
1743 return (error);
1744
1745 /*
1746 * Allocate room for the argument and environment strings.
1747 */
1748 destp -= ARG_MAX - imgp->args->stringspace;
1749 destp = rounddown2(destp, sizeof(void *));
1750 ustringp = destp;
1751
1752 if (imgp->auxargs) {
1753 /*
1754 * Allocate room on the stack for the ELF auxargs
1755 * array. It has up to AT_COUNT entries.
1756 */
1757 destp -= AT_COUNT * sizeof(Elf_Auxinfo);
1758 destp = rounddown2(destp, sizeof(void *));
1759 }
1760
1761 vectp = (char **)destp;
1762
1763 /*
1764 * Allocate room for the argv[] and env vectors including the
1765 * terminating NULL pointers.
1766 */
1767 vectp -= imgp->args->argc + 1 + imgp->args->envc + 1;
1768
1769 /*
1770 * vectp also becomes our initial stack base
1771 */
1772 *stack_base = (uintptr_t)vectp;
1773
1774 stringp = imgp->args->begin_argv;
1775 argc = imgp->args->argc;
1776 envc = imgp->args->envc;
1777
1778 /*
1779 * Copy out strings - arguments and environment.
1780 */
1781 error = copyout(stringp, (void *)ustringp,
1782 ARG_MAX - imgp->args->stringspace);
1783 if (error != 0)
1784 return (error);
1785
1786 /*
1787 * Fill in "ps_strings" struct for ps, w, etc.
1788 */
1789 imgp->argv = vectp;
1790 if (suword(&arginfo->ps_argvstr, (long)(intptr_t)vectp) != 0 ||
1791 suword32(&arginfo->ps_nargvstr, argc) != 0)
1792 return (EFAULT);
1793
1794 /*
1795 * Fill in argument portion of vector table.
1796 */
1797 for (; argc > 0; --argc) {
1798 if (suword(vectp++, ustringp) != 0)
1799 return (EFAULT);
1800 while (*stringp++ != 0)
1801 ustringp++;
1802 ustringp++;
1803 }
1804
1805 /* a null vector table pointer separates the argp's from the envp's */
1806 if (suword(vectp++, 0) != 0)
1807 return (EFAULT);
1808
1809 imgp->envv = vectp;
1810 if (suword(&arginfo->ps_envstr, (long)(intptr_t)vectp) != 0 ||
1811 suword32(&arginfo->ps_nenvstr, envc) != 0)
1812 return (EFAULT);
1813
1814 /*
1815 * Fill in environment portion of vector table.
1816 */
1817 for (; envc > 0; --envc) {
1818 if (suword(vectp++, ustringp) != 0)
1819 return (EFAULT);
1820 while (*stringp++ != 0)
1821 ustringp++;
1822 ustringp++;
1823 }
1824
1825 /* end of vector table is a null pointer */
1826 if (suword(vectp, 0) != 0)
1827 return (EFAULT);
1828
1829 if (imgp->auxargs) {
1830 vectp++;
1831 error = imgp->sysent->sv_copyout_auxargs(imgp,
1832 (uintptr_t)vectp);
1833 if (error != 0)
1834 return (error);
1835 }
1836
1837 return (0);
1838 }
1839
1840 /*
1841 * Check permissions of file to execute.
1842 * Called with imgp->vp locked.
1843 * Return 0 for success or error code on failure.
1844 */
1845 int
exec_check_permissions(struct image_params * imgp)1846 exec_check_permissions(struct image_params *imgp)
1847 {
1848 struct vnode *vp = imgp->vp;
1849 struct vattr *attr = imgp->attr;
1850 struct thread *td;
1851 int error;
1852
1853 td = curthread;
1854
1855 /* Get file attributes */
1856 error = VOP_GETATTR(vp, attr, td->td_ucred);
1857 if (error)
1858 return (error);
1859
1860 #ifdef MAC
1861 error = mac_vnode_check_exec(td->td_ucred, imgp->vp, imgp);
1862 if (error)
1863 return (error);
1864 #endif
1865
1866 /*
1867 * 1) Check if file execution is disabled for the filesystem that
1868 * this file resides on.
1869 * 2) Ensure that at least one execute bit is on. Otherwise, a
1870 * privileged user will always succeed, and we don't want this
1871 * to happen unless the file really is executable.
1872 * 3) Ensure that the file is a regular file.
1873 */
1874 if ((vp->v_mount->mnt_flag & MNT_NOEXEC) ||
1875 (attr->va_mode & (S_IXUSR | S_IXGRP | S_IXOTH)) == 0 ||
1876 (attr->va_type != VREG))
1877 return (EACCES);
1878
1879 /*
1880 * Zero length files can't be exec'd
1881 */
1882 if (attr->va_size == 0)
1883 return (ENOEXEC);
1884
1885 /*
1886 * Check for execute permission to file based on current credentials.
1887 */
1888 error = VOP_ACCESS(vp, VEXEC, td->td_ucred, td);
1889 if (error)
1890 return (error);
1891
1892 /*
1893 * Check number of open-for-writes on the file and deny execution
1894 * if there are any.
1895 *
1896 * Add a text reference now so no one can write to the
1897 * executable while we're activating it.
1898 *
1899 * Remember if this was set before and unset it in case this is not
1900 * actually an executable image.
1901 */
1902 error = VOP_SET_TEXT(vp);
1903 if (error != 0)
1904 return (error);
1905 imgp->textset = true;
1906
1907 /*
1908 * Call filesystem specific open routine (which does nothing in the
1909 * general case).
1910 */
1911 error = VOP_OPEN(vp, FREAD, td->td_ucred, td, NULL);
1912 if (error == 0)
1913 imgp->opened = true;
1914 return (error);
1915 }
1916
1917 /*
1918 * Exec handler registration
1919 */
1920 int
exec_register(const struct execsw * execsw_arg)1921 exec_register(const struct execsw *execsw_arg)
1922 {
1923 const struct execsw **es, **xs, **newexecsw;
1924 u_int count = 2; /* New slot and trailing NULL */
1925
1926 if (execsw)
1927 for (es = execsw; *es; es++)
1928 count++;
1929 newexecsw = malloc(count * sizeof(*es), M_TEMP, M_WAITOK);
1930 xs = newexecsw;
1931 if (execsw)
1932 for (es = execsw; *es; es++)
1933 *xs++ = *es;
1934 *xs++ = execsw_arg;
1935 *xs = NULL;
1936 if (execsw)
1937 free(execsw, M_TEMP);
1938 execsw = newexecsw;
1939 return (0);
1940 }
1941
1942 int
exec_unregister(const struct execsw * execsw_arg)1943 exec_unregister(const struct execsw *execsw_arg)
1944 {
1945 const struct execsw **es, **xs, **newexecsw;
1946 int count = 1;
1947
1948 if (execsw == NULL)
1949 panic("unregister with no handlers left?\n");
1950
1951 for (es = execsw; *es; es++) {
1952 if (*es == execsw_arg)
1953 break;
1954 }
1955 if (*es == NULL)
1956 return (ENOENT);
1957 for (es = execsw; *es; es++)
1958 if (*es != execsw_arg)
1959 count++;
1960 newexecsw = malloc(count * sizeof(*es), M_TEMP, M_WAITOK);
1961 xs = newexecsw;
1962 for (es = execsw; *es; es++)
1963 if (*es != execsw_arg)
1964 *xs++ = *es;
1965 *xs = NULL;
1966 if (execsw)
1967 free(execsw, M_TEMP);
1968 execsw = newexecsw;
1969 return (0);
1970 }
1971
1972 /*
1973 * Write out a core segment to the compression stream.
1974 */
1975 static int
compress_chunk(struct coredump_params * cp,char * base,char * buf,size_t len)1976 compress_chunk(struct coredump_params *cp, char *base, char *buf, size_t len)
1977 {
1978 size_t chunk_len;
1979 int error;
1980
1981 error = 0;
1982 while (len > 0) {
1983 chunk_len = MIN(len, CORE_BUF_SIZE);
1984
1985 /*
1986 * We can get EFAULT error here.
1987 * In that case zero out the current chunk of the segment.
1988 */
1989 error = copyin(base, buf, chunk_len);
1990 if (error != 0)
1991 bzero(buf, chunk_len);
1992 error = compressor_write(cp->comp, buf, chunk_len);
1993 if (error != 0)
1994 break;
1995 base += chunk_len;
1996 len -= chunk_len;
1997 }
1998 return (error);
1999 }
2000
2001 int
core_write(struct coredump_params * cp,const void * base,size_t len,off_t offset,enum uio_seg seg,size_t * resid)2002 core_write(struct coredump_params *cp, const void *base, size_t len,
2003 off_t offset, enum uio_seg seg, size_t *resid)
2004 {
2005
2006 return (vn_rdwr_inchunks(UIO_WRITE, cp->vp, __DECONST(void *, base),
2007 len, offset, seg, IO_UNIT | IO_DIRECT | IO_RANGELOCKED,
2008 cp->active_cred, cp->file_cred, resid, cp->td));
2009 }
2010
2011 int
core_output(char * base,size_t len,off_t offset,struct coredump_params * cp,void * tmpbuf)2012 core_output(char *base, size_t len, off_t offset, struct coredump_params *cp,
2013 void *tmpbuf)
2014 {
2015 vm_map_t map;
2016 struct mount *mp;
2017 size_t resid, runlen;
2018 int error;
2019 bool success;
2020
2021 KASSERT((uintptr_t)base % PAGE_SIZE == 0,
2022 ("%s: user address %p is not page-aligned", __func__, base));
2023
2024 if (cp->comp != NULL)
2025 return (compress_chunk(cp, base, tmpbuf, len));
2026
2027 error = 0;
2028 map = &cp->td->td_proc->p_vmspace->vm_map;
2029 for (; len > 0; base += runlen, offset += runlen, len -= runlen) {
2030 /*
2031 * Attempt to page in all virtual pages in the range. If a
2032 * virtual page is not backed by the pager, it is represented as
2033 * a hole in the file. This can occur with zero-filled
2034 * anonymous memory or truncated files, for example.
2035 */
2036 for (runlen = 0; runlen < len; runlen += PAGE_SIZE) {
2037 if (core_dump_can_intr && curproc_sigkilled())
2038 return (EINTR);
2039 error = vm_fault(map, (uintptr_t)base + runlen,
2040 VM_PROT_READ, VM_FAULT_NOFILL, NULL);
2041 if (runlen == 0)
2042 success = error == KERN_SUCCESS;
2043 else if ((error == KERN_SUCCESS) != success)
2044 break;
2045 }
2046
2047 if (success) {
2048 error = core_write(cp, base, runlen, offset,
2049 UIO_USERSPACE, &resid);
2050 if (error != 0) {
2051 if (error != EFAULT)
2052 break;
2053
2054 /*
2055 * EFAULT may be returned if the user mapping
2056 * could not be accessed, e.g., because a mapped
2057 * file has been truncated. Skip the page if no
2058 * progress was made, to protect against a
2059 * hypothetical scenario where vm_fault() was
2060 * successful but core_write() returns EFAULT
2061 * anyway.
2062 */
2063 runlen -= resid;
2064 if (runlen == 0) {
2065 success = false;
2066 runlen = PAGE_SIZE;
2067 }
2068 }
2069 }
2070 if (!success) {
2071 error = vn_start_write(cp->vp, &mp, V_WAIT);
2072 if (error != 0)
2073 break;
2074 vn_lock(cp->vp, LK_EXCLUSIVE | LK_RETRY);
2075 error = vn_truncate_locked(cp->vp, offset + runlen,
2076 false, cp->td->td_ucred);
2077 VOP_UNLOCK(cp->vp);
2078 vn_finished_write(mp);
2079 if (error != 0)
2080 break;
2081 }
2082 }
2083 return (error);
2084 }
2085
2086 /*
2087 * Drain into a core file.
2088 */
2089 int
sbuf_drain_core_output(void * arg,const char * data,int len)2090 sbuf_drain_core_output(void *arg, const char *data, int len)
2091 {
2092 struct coredump_params *cp;
2093 struct proc *p;
2094 int error, locked;
2095
2096 cp = arg;
2097 p = cp->td->td_proc;
2098
2099 /*
2100 * Some kern_proc out routines that print to this sbuf may
2101 * call us with the process lock held. Draining with the
2102 * non-sleepable lock held is unsafe. The lock is needed for
2103 * those routines when dumping a live process. In our case we
2104 * can safely release the lock before draining and acquire
2105 * again after.
2106 */
2107 locked = PROC_LOCKED(p);
2108 if (locked)
2109 PROC_UNLOCK(p);
2110 if (cp->comp != NULL)
2111 error = compressor_write(cp->comp, __DECONST(char *, data),
2112 len);
2113 else
2114 error = core_write(cp, __DECONST(void *, data), len, cp->offset,
2115 UIO_SYSSPACE, NULL);
2116 if (locked)
2117 PROC_LOCK(p);
2118 if (error != 0)
2119 return (-error);
2120 cp->offset += len;
2121 return (len);
2122 }
2123