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