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