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 return (do_execve(td, args, mac_p, oldvmspace)); 360 } 361 362 static void 363 execve_nosetid(struct image_params *imgp) 364 { 365 imgp->credential_setid = false; 366 if (imgp->newcred != NULL) { 367 crfree(imgp->newcred); 368 imgp->newcred = NULL; 369 } 370 } 371 372 /* 373 * In-kernel implementation of execve(). All arguments are assumed to be 374 * userspace pointers from the passed thread. 375 */ 376 static int 377 do_execve(struct thread *td, struct image_args *args, struct mac *mac_p, 378 struct vmspace *oldvmspace) 379 { 380 struct proc *p = td->td_proc; 381 struct nameidata nd; 382 struct ucred *oldcred; 383 struct uidinfo *euip = NULL; 384 uintptr_t stack_base; 385 struct image_params image_params, *imgp; 386 struct vattr attr; 387 int (*img_first)(struct image_params *); 388 struct pargs *oldargs = NULL, *newargs = NULL; 389 struct sigacts *oldsigacts = NULL, *newsigacts = NULL; 390 #ifdef KTRACE 391 struct ktr_io_params *kiop; 392 #endif 393 struct vnode *oldtextvp, *newtextvp; 394 struct vnode *oldtextdvp, *newtextdvp; 395 char *oldbinname, *newbinname; 396 bool credential_changing; 397 #ifdef MAC 398 struct label *interpvplabel = NULL; 399 bool will_transition; 400 #endif 401 #ifdef HWPMC_HOOKS 402 struct pmckern_procexec pe; 403 #endif 404 int error, i, orig_osrel; 405 uint32_t orig_fctl0; 406 Elf_Brandinfo *orig_brandinfo; 407 size_t freepath_size; 408 static const char fexecv_proc_title[] = "(fexecv)"; 409 410 imgp = &image_params; 411 oldtextvp = oldtextdvp = NULL; 412 newtextvp = newtextdvp = NULL; 413 newbinname = oldbinname = NULL; 414 #ifdef KTRACE 415 kiop = NULL; 416 #endif 417 418 /* 419 * Lock the process and set the P_INEXEC flag to indicate that 420 * it should be left alone until we're done here. This is 421 * necessary to avoid race conditions - e.g. in ptrace() - 422 * that might allow a local user to illicitly obtain elevated 423 * privileges. 424 */ 425 PROC_LOCK(p); 426 KASSERT((p->p_flag & P_INEXEC) == 0, 427 ("%s(): process already has P_INEXEC flag", __func__)); 428 p->p_flag |= P_INEXEC; 429 PROC_UNLOCK(p); 430 431 /* 432 * Initialize part of the common data 433 */ 434 bzero(imgp, sizeof(*imgp)); 435 imgp->proc = p; 436 imgp->attr = &attr; 437 imgp->args = args; 438 oldcred = p->p_ucred; 439 orig_osrel = p->p_osrel; 440 orig_fctl0 = p->p_fctl0; 441 orig_brandinfo = p->p_elf_brandinfo; 442 443 #ifdef MAC 444 error = mac_execve_enter(imgp, mac_p); 445 if (error) 446 goto exec_fail; 447 #endif 448 449 SDT_PROBE1(proc, , , exec, args->fname); 450 451 interpret: 452 if (args->fname != NULL) { 453 #ifdef CAPABILITY_MODE 454 /* 455 * While capability mode can't reach this point via direct 456 * path arguments to execve(), we also don't allow 457 * interpreters to be used in capability mode (for now). 458 * Catch indirect lookups and return a permissions error. 459 */ 460 if (IN_CAPABILITY_MODE(td)) { 461 error = ECAPMODE; 462 goto exec_fail; 463 } 464 #endif 465 466 /* 467 * Translate the file name. namei() returns a vnode 468 * pointer in ni_vp among other things. 469 */ 470 NDINIT(&nd, LOOKUP, ISOPEN | LOCKLEAF | LOCKSHARED | FOLLOW | 471 SAVENAME | AUDITVNODE1 | WANTPARENT, UIO_SYSSPACE, 472 args->fname); 473 474 error = namei(&nd); 475 if (error) 476 goto exec_fail; 477 478 newtextvp = nd.ni_vp; 479 newtextdvp = nd.ni_dvp; 480 nd.ni_dvp = NULL; 481 newbinname = malloc(nd.ni_cnd.cn_namelen + 1, M_PARGS, 482 M_WAITOK); 483 memcpy(newbinname, nd.ni_cnd.cn_nameptr, nd.ni_cnd.cn_namelen); 484 newbinname[nd.ni_cnd.cn_namelen] = '\0'; 485 imgp->vp = newtextvp; 486 487 /* 488 * Do the best to calculate the full path to the image file. 489 */ 490 if (args->fname[0] == '/') { 491 imgp->execpath = args->fname; 492 } else { 493 VOP_UNLOCK(imgp->vp); 494 freepath_size = MAXPATHLEN; 495 if (vn_fullpath_hardlink(newtextvp, newtextdvp, 496 newbinname, nd.ni_cnd.cn_namelen, &imgp->execpath, 497 &imgp->freepath, &freepath_size) != 0) 498 imgp->execpath = args->fname; 499 vn_lock(imgp->vp, LK_SHARED | LK_RETRY); 500 } 501 } else { 502 AUDIT_ARG_FD(args->fd); 503 504 /* 505 * If the descriptors was not opened with O_PATH, then 506 * we require that it was opened with O_EXEC or 507 * O_RDONLY. In either case, exec_check_permissions() 508 * below checks _current_ file access mode regardless 509 * of the permissions additionally checked at the 510 * open(2). 511 */ 512 error = fgetvp_exec(td, args->fd, &cap_fexecve_rights, 513 &newtextvp); 514 if (error != 0) 515 goto exec_fail; 516 517 if (vn_fullpath(newtextvp, &imgp->execpath, 518 &imgp->freepath) != 0) 519 imgp->execpath = args->fname; 520 vn_lock(newtextvp, LK_SHARED | LK_RETRY); 521 AUDIT_ARG_VNODE1(newtextvp); 522 imgp->vp = newtextvp; 523 } 524 525 /* 526 * Check file permissions. Also 'opens' file and sets its vnode to 527 * text mode. 528 */ 529 error = exec_check_permissions(imgp); 530 if (error) 531 goto exec_fail_dealloc; 532 533 imgp->object = imgp->vp->v_object; 534 if (imgp->object != NULL) 535 vm_object_reference(imgp->object); 536 537 error = exec_map_first_page(imgp); 538 if (error) 539 goto exec_fail_dealloc; 540 541 imgp->proc->p_osrel = 0; 542 imgp->proc->p_fctl0 = 0; 543 imgp->proc->p_elf_brandinfo = NULL; 544 545 /* 546 * Implement image setuid/setgid. 547 * 548 * Determine new credentials before attempting image activators 549 * so that it can be used by process_exec handlers to determine 550 * credential/setid changes. 551 * 552 * Don't honor setuid/setgid if the filesystem prohibits it or if 553 * the process is being traced. 554 * 555 * We disable setuid/setgid/etc in capability mode on the basis 556 * that most setugid applications are not written with that 557 * environment in mind, and will therefore almost certainly operate 558 * incorrectly. In principle there's no reason that setugid 559 * applications might not be useful in capability mode, so we may want 560 * to reconsider this conservative design choice in the future. 561 * 562 * XXXMAC: For the time being, use NOSUID to also prohibit 563 * transitions on the file system. 564 */ 565 credential_changing = false; 566 credential_changing |= (attr.va_mode & S_ISUID) && 567 oldcred->cr_uid != attr.va_uid; 568 credential_changing |= (attr.va_mode & S_ISGID) && 569 oldcred->cr_gid != attr.va_gid; 570 #ifdef MAC 571 will_transition = mac_vnode_execve_will_transition(oldcred, imgp->vp, 572 interpvplabel, imgp) != 0; 573 credential_changing |= will_transition; 574 #endif 575 576 /* Don't inherit PROC_PDEATHSIG_CTL value if setuid/setgid. */ 577 if (credential_changing) 578 imgp->proc->p_pdeathsig = 0; 579 580 if (credential_changing && 581 #ifdef CAPABILITY_MODE 582 ((oldcred->cr_flags & CRED_FLAG_CAPMODE) == 0) && 583 #endif 584 (imgp->vp->v_mount->mnt_flag & MNT_NOSUID) == 0 && 585 (p->p_flag & P_TRACED) == 0) { 586 imgp->credential_setid = true; 587 VOP_UNLOCK(imgp->vp); 588 imgp->newcred = crdup(oldcred); 589 if (attr.va_mode & S_ISUID) { 590 euip = uifind(attr.va_uid); 591 change_euid(imgp->newcred, euip); 592 } 593 vn_lock(imgp->vp, LK_SHARED | LK_RETRY); 594 if (attr.va_mode & S_ISGID) 595 change_egid(imgp->newcred, attr.va_gid); 596 /* 597 * Implement correct POSIX saved-id behavior. 598 * 599 * XXXMAC: Note that the current logic will save the 600 * uid and gid if a MAC domain transition occurs, even 601 * though maybe it shouldn't. 602 */ 603 change_svuid(imgp->newcred, imgp->newcred->cr_uid); 604 change_svgid(imgp->newcred, imgp->newcred->cr_gid); 605 } else { 606 /* 607 * Implement correct POSIX saved-id behavior. 608 * 609 * XXX: It's not clear that the existing behavior is 610 * POSIX-compliant. A number of sources indicate that the 611 * saved uid/gid should only be updated if the new ruid is 612 * not equal to the old ruid, or the new euid is not equal 613 * to the old euid and the new euid is not equal to the old 614 * ruid. The FreeBSD code always updates the saved uid/gid. 615 * Also, this code uses the new (replaced) euid and egid as 616 * the source, which may or may not be the right ones to use. 617 */ 618 if (oldcred->cr_svuid != oldcred->cr_uid || 619 oldcred->cr_svgid != oldcred->cr_gid) { 620 VOP_UNLOCK(imgp->vp); 621 imgp->newcred = crdup(oldcred); 622 vn_lock(imgp->vp, LK_SHARED | LK_RETRY); 623 change_svuid(imgp->newcred, imgp->newcred->cr_uid); 624 change_svgid(imgp->newcred, imgp->newcred->cr_gid); 625 } 626 } 627 /* The new credentials are installed into the process later. */ 628 629 /* 630 * If the current process has a special image activator it 631 * wants to try first, call it. For example, emulating shell 632 * scripts differently. 633 */ 634 error = -1; 635 if ((img_first = imgp->proc->p_sysent->sv_imgact_try) != NULL) 636 error = img_first(imgp); 637 638 /* 639 * Loop through the list of image activators, calling each one. 640 * An activator returns -1 if there is no match, 0 on success, 641 * and an error otherwise. 642 */ 643 for (i = 0; error == -1 && execsw[i]; ++i) { 644 if (execsw[i]->ex_imgact == NULL || 645 execsw[i]->ex_imgact == img_first) { 646 continue; 647 } 648 error = (*execsw[i]->ex_imgact)(imgp); 649 } 650 651 if (error) { 652 if (error == -1) 653 error = ENOEXEC; 654 goto exec_fail_dealloc; 655 } 656 657 /* 658 * Special interpreter operation, cleanup and loop up to try to 659 * activate the interpreter. 660 */ 661 if (imgp->interpreted) { 662 exec_unmap_first_page(imgp); 663 /* 664 * The text reference needs to be removed for scripts. 665 * There is a short period before we determine that 666 * something is a script where text reference is active. 667 * The vnode lock is held over this entire period 668 * so nothing should illegitimately be blocked. 669 */ 670 MPASS(imgp->textset); 671 VOP_UNSET_TEXT_CHECKED(newtextvp); 672 imgp->textset = false; 673 /* free name buffer and old vnode */ 674 #ifdef MAC 675 mac_execve_interpreter_enter(newtextvp, &interpvplabel); 676 #endif 677 if (imgp->opened) { 678 VOP_CLOSE(newtextvp, FREAD, td->td_ucred, td); 679 imgp->opened = false; 680 } 681 vput(newtextvp); 682 imgp->vp = newtextvp = NULL; 683 if (args->fname != NULL) { 684 if (newtextdvp != NULL) { 685 vrele(newtextdvp); 686 newtextdvp = NULL; 687 } 688 NDFREE(&nd, NDF_ONLY_PNBUF); 689 free(newbinname, M_PARGS); 690 newbinname = NULL; 691 } 692 vm_object_deallocate(imgp->object); 693 imgp->object = NULL; 694 execve_nosetid(imgp); 695 imgp->execpath = NULL; 696 free(imgp->freepath, M_TEMP); 697 imgp->freepath = NULL; 698 /* set new name to that of the interpreter */ 699 args->fname = imgp->interpreter_name; 700 goto interpret; 701 } 702 703 /* 704 * NB: We unlock the vnode here because it is believed that none 705 * of the sv_copyout_strings/sv_fixup operations require the vnode. 706 */ 707 VOP_UNLOCK(imgp->vp); 708 709 if (disallow_high_osrel && 710 P_OSREL_MAJOR(p->p_osrel) > P_OSREL_MAJOR(__FreeBSD_version)) { 711 error = ENOEXEC; 712 uprintf("Osrel %d for image %s too high\n", p->p_osrel, 713 imgp->execpath != NULL ? imgp->execpath : "<unresolved>"); 714 vn_lock(imgp->vp, LK_SHARED | LK_RETRY); 715 goto exec_fail_dealloc; 716 } 717 718 /* 719 * Copy out strings (args and env) and initialize stack base. 720 */ 721 error = (*p->p_sysent->sv_copyout_strings)(imgp, &stack_base); 722 if (error != 0) { 723 vn_lock(imgp->vp, LK_SHARED | LK_RETRY); 724 goto exec_fail_dealloc; 725 } 726 727 /* 728 * Stack setup. 729 */ 730 error = (*p->p_sysent->sv_fixup)(&stack_base, imgp); 731 if (error != 0) { 732 vn_lock(imgp->vp, LK_SHARED | LK_RETRY); 733 goto exec_fail_dealloc; 734 } 735 736 /* 737 * For security and other reasons, the file descriptor table cannot be 738 * shared after an exec. 739 */ 740 fdunshare(td); 741 pdunshare(td); 742 /* close files on exec */ 743 fdcloseexec(td); 744 745 /* 746 * Malloc things before we need locks. 747 */ 748 i = exec_args_get_begin_envv(imgp->args) - imgp->args->begin_argv; 749 /* Cache arguments if they fit inside our allowance */ 750 if (ps_arg_cache_limit >= i + sizeof(struct pargs)) { 751 newargs = pargs_alloc(i); 752 bcopy(imgp->args->begin_argv, newargs->ar_args, i); 753 } 754 755 /* 756 * For security and other reasons, signal handlers cannot 757 * be shared after an exec. The new process gets a copy of the old 758 * handlers. In execsigs(), the new process will have its signals 759 * reset. 760 */ 761 if (sigacts_shared(p->p_sigacts)) { 762 oldsigacts = p->p_sigacts; 763 newsigacts = sigacts_alloc(); 764 sigacts_copy(newsigacts, oldsigacts); 765 } 766 767 vn_lock(imgp->vp, LK_SHARED | LK_RETRY); 768 769 PROC_LOCK(p); 770 if (oldsigacts) 771 p->p_sigacts = newsigacts; 772 /* Stop profiling */ 773 stopprofclock(p); 774 775 /* reset caught signals */ 776 execsigs(p); 777 778 /* name this process - nameiexec(p, ndp) */ 779 bzero(p->p_comm, sizeof(p->p_comm)); 780 if (args->fname) 781 bcopy(nd.ni_cnd.cn_nameptr, p->p_comm, 782 min(nd.ni_cnd.cn_namelen, MAXCOMLEN)); 783 else if (vn_commname(newtextvp, p->p_comm, sizeof(p->p_comm)) != 0) 784 bcopy(fexecv_proc_title, p->p_comm, sizeof(fexecv_proc_title)); 785 bcopy(p->p_comm, td->td_name, sizeof(td->td_name)); 786 #ifdef KTR 787 sched_clear_tdname(td); 788 #endif 789 790 /* 791 * mark as execed, wakeup the process that vforked (if any) and tell 792 * it that it now has its own resources back 793 */ 794 p->p_flag |= P_EXEC; 795 if ((p->p_flag2 & P2_NOTRACE_EXEC) == 0) 796 p->p_flag2 &= ~P2_NOTRACE; 797 if ((p->p_flag2 & P2_STKGAP_DISABLE_EXEC) == 0) 798 p->p_flag2 &= ~P2_STKGAP_DISABLE; 799 if (p->p_flag & P_PPWAIT) { 800 p->p_flag &= ~(P_PPWAIT | P_PPTRACE); 801 cv_broadcast(&p->p_pwait); 802 /* STOPs are no longer ignored, arrange for AST */ 803 signotify(td); 804 } 805 806 if ((imgp->sysent->sv_setid_allowed != NULL && 807 !(*imgp->sysent->sv_setid_allowed)(td, imgp)) || 808 (p->p_flag2 & P2_NO_NEW_PRIVS) != 0) 809 execve_nosetid(imgp); 810 811 /* 812 * Implement image setuid/setgid installation. 813 */ 814 if (imgp->credential_setid) { 815 /* 816 * Turn off syscall tracing for set-id programs, except for 817 * root. Record any set-id flags first to make sure that 818 * we do not regain any tracing during a possible block. 819 */ 820 setsugid(p); 821 #ifdef KTRACE 822 kiop = ktrprocexec(p); 823 #endif 824 /* 825 * Close any file descriptors 0..2 that reference procfs, 826 * then make sure file descriptors 0..2 are in use. 827 * 828 * Both fdsetugidsafety() and fdcheckstd() may call functions 829 * taking sleepable locks, so temporarily drop our locks. 830 */ 831 PROC_UNLOCK(p); 832 VOP_UNLOCK(imgp->vp); 833 fdsetugidsafety(td); 834 error = fdcheckstd(td); 835 vn_lock(imgp->vp, LK_SHARED | LK_RETRY); 836 if (error != 0) 837 goto exec_fail_dealloc; 838 PROC_LOCK(p); 839 #ifdef MAC 840 if (will_transition) { 841 mac_vnode_execve_transition(oldcred, imgp->newcred, 842 imgp->vp, interpvplabel, imgp); 843 } 844 #endif 845 } else { 846 if (oldcred->cr_uid == oldcred->cr_ruid && 847 oldcred->cr_gid == oldcred->cr_rgid) 848 p->p_flag &= ~P_SUGID; 849 } 850 /* 851 * Set the new credentials. 852 */ 853 if (imgp->newcred != NULL) { 854 proc_set_cred(p, imgp->newcred); 855 crfree(oldcred); 856 oldcred = NULL; 857 } 858 859 /* 860 * Store the vp for use in kern.proc.pathname. This vnode was 861 * referenced by namei() or by fexecve variant of fname handling. 862 */ 863 oldtextvp = p->p_textvp; 864 p->p_textvp = newtextvp; 865 oldtextdvp = p->p_textdvp; 866 p->p_textdvp = newtextdvp; 867 newtextdvp = NULL; 868 oldbinname = p->p_binname; 869 p->p_binname = newbinname; 870 newbinname = NULL; 871 872 #ifdef KDTRACE_HOOKS 873 /* 874 * Tell the DTrace fasttrap provider about the exec if it 875 * has declared an interest. 876 */ 877 if (dtrace_fasttrap_exec) 878 dtrace_fasttrap_exec(p); 879 #endif 880 881 /* 882 * Notify others that we exec'd, and clear the P_INEXEC flag 883 * as we're now a bona fide freshly-execed process. 884 */ 885 KNOTE_LOCKED(p->p_klist, NOTE_EXEC); 886 p->p_flag &= ~P_INEXEC; 887 888 /* clear "fork but no exec" flag, as we _are_ execing */ 889 p->p_acflag &= ~AFORK; 890 891 /* 892 * Free any previous argument cache and replace it with 893 * the new argument cache, if any. 894 */ 895 oldargs = p->p_args; 896 p->p_args = newargs; 897 newargs = NULL; 898 899 PROC_UNLOCK(p); 900 901 #ifdef HWPMC_HOOKS 902 /* 903 * Check if system-wide sampling is in effect or if the 904 * current process is using PMCs. If so, do exec() time 905 * processing. This processing needs to happen AFTER the 906 * P_INEXEC flag is cleared. 907 */ 908 if (PMC_SYSTEM_SAMPLING_ACTIVE() || PMC_PROC_IS_USING_PMCS(p)) { 909 VOP_UNLOCK(imgp->vp); 910 pe.pm_credentialschanged = credential_changing; 911 pe.pm_entryaddr = imgp->entry_addr; 912 913 PMC_CALL_HOOK_X(td, PMC_FN_PROCESS_EXEC, (void *) &pe); 914 vn_lock(imgp->vp, LK_SHARED | LK_RETRY); 915 } 916 #endif 917 918 /* Set values passed into the program in registers. */ 919 (*p->p_sysent->sv_setregs)(td, imgp, stack_base); 920 921 VOP_MMAPPED(imgp->vp); 922 923 SDT_PROBE1(proc, , , exec__success, args->fname); 924 925 exec_fail_dealloc: 926 if (error != 0) { 927 p->p_osrel = orig_osrel; 928 p->p_fctl0 = orig_fctl0; 929 p->p_elf_brandinfo = orig_brandinfo; 930 } 931 932 if (imgp->firstpage != NULL) 933 exec_unmap_first_page(imgp); 934 935 if (imgp->vp != NULL) { 936 if (imgp->opened) 937 VOP_CLOSE(imgp->vp, FREAD, td->td_ucred, td); 938 if (imgp->textset) 939 VOP_UNSET_TEXT_CHECKED(imgp->vp); 940 if (error != 0) 941 vput(imgp->vp); 942 else 943 VOP_UNLOCK(imgp->vp); 944 if (args->fname != NULL) 945 NDFREE(&nd, NDF_ONLY_PNBUF); 946 if (newtextdvp != NULL) 947 vrele(newtextdvp); 948 free(newbinname, M_PARGS); 949 } 950 951 if (imgp->object != NULL) 952 vm_object_deallocate(imgp->object); 953 954 free(imgp->freepath, M_TEMP); 955 956 if (error == 0) { 957 if (p->p_ptevents & PTRACE_EXEC) { 958 PROC_LOCK(p); 959 if (p->p_ptevents & PTRACE_EXEC) 960 td->td_dbgflags |= TDB_EXEC; 961 PROC_UNLOCK(p); 962 } 963 } else { 964 exec_fail: 965 /* we're done here, clear P_INEXEC */ 966 PROC_LOCK(p); 967 p->p_flag &= ~P_INEXEC; 968 PROC_UNLOCK(p); 969 970 SDT_PROBE1(proc, , , exec__failure, error); 971 } 972 973 if (imgp->newcred != NULL && oldcred != NULL) 974 crfree(imgp->newcred); 975 976 #ifdef MAC 977 mac_execve_exit(imgp); 978 mac_execve_interpreter_exit(interpvplabel); 979 #endif 980 exec_free_args(args); 981 982 /* 983 * Handle deferred decrement of ref counts. 984 */ 985 if (oldtextvp != NULL) 986 vrele(oldtextvp); 987 if (oldtextdvp != NULL) 988 vrele(oldtextdvp); 989 free(oldbinname, M_PARGS); 990 #ifdef KTRACE 991 ktr_io_params_free(kiop); 992 #endif 993 pargs_drop(oldargs); 994 pargs_drop(newargs); 995 if (oldsigacts != NULL) 996 sigacts_free(oldsigacts); 997 if (euip != NULL) 998 uifree(euip); 999 1000 if (error && imgp->vmspace_destroyed) { 1001 /* sorry, no more process anymore. exit gracefully */ 1002 exec_cleanup(td, oldvmspace); 1003 exit1(td, 0, SIGABRT); 1004 /* NOT REACHED */ 1005 } 1006 1007 #ifdef KTRACE 1008 if (error == 0) 1009 ktrprocctor(p); 1010 #endif 1011 1012 /* 1013 * We don't want cpu_set_syscall_retval() to overwrite any of 1014 * the register values put in place by exec_setregs(). 1015 * Implementations of cpu_set_syscall_retval() will leave 1016 * registers unmodified when returning EJUSTRETURN. 1017 */ 1018 return (error == 0 ? EJUSTRETURN : error); 1019 } 1020 1021 void 1022 exec_cleanup(struct thread *td, struct vmspace *oldvmspace) 1023 { 1024 if ((td->td_pflags & TDP_EXECVMSPC) != 0) { 1025 KASSERT(td->td_proc->p_vmspace != oldvmspace, 1026 ("oldvmspace still used")); 1027 vmspace_free(oldvmspace); 1028 td->td_pflags &= ~TDP_EXECVMSPC; 1029 } 1030 } 1031 1032 int 1033 exec_map_first_page(struct image_params *imgp) 1034 { 1035 vm_object_t object; 1036 vm_page_t m; 1037 int error; 1038 1039 if (imgp->firstpage != NULL) 1040 exec_unmap_first_page(imgp); 1041 1042 object = imgp->vp->v_object; 1043 if (object == NULL) 1044 return (EACCES); 1045 #if VM_NRESERVLEVEL > 0 1046 if ((object->flags & OBJ_COLORED) == 0) { 1047 VM_OBJECT_WLOCK(object); 1048 vm_object_color(object, 0); 1049 VM_OBJECT_WUNLOCK(object); 1050 } 1051 #endif 1052 error = vm_page_grab_valid_unlocked(&m, object, 0, 1053 VM_ALLOC_COUNT(VM_INITIAL_PAGEIN) | 1054 VM_ALLOC_NORMAL | VM_ALLOC_NOBUSY | VM_ALLOC_WIRED); 1055 1056 if (error != VM_PAGER_OK) 1057 return (EIO); 1058 imgp->firstpage = sf_buf_alloc(m, 0); 1059 imgp->image_header = (char *)sf_buf_kva(imgp->firstpage); 1060 1061 return (0); 1062 } 1063 1064 void 1065 exec_unmap_first_page(struct image_params *imgp) 1066 { 1067 vm_page_t m; 1068 1069 if (imgp->firstpage != NULL) { 1070 m = sf_buf_page(imgp->firstpage); 1071 sf_buf_free(imgp->firstpage); 1072 imgp->firstpage = NULL; 1073 vm_page_unwire(m, PQ_ACTIVE); 1074 } 1075 } 1076 1077 void 1078 exec_onexec_old(struct thread *td) 1079 { 1080 sigfastblock_clear(td); 1081 umtx_exec(td->td_proc); 1082 } 1083 1084 /* 1085 * This is an optimization which removes the unmanaged shared page 1086 * mapping. In combination with pmap_remove_pages(), which cleans all 1087 * managed mappings in the process' vmspace pmap, no work will be left 1088 * for pmap_remove(min, max). 1089 */ 1090 void 1091 exec_free_abi_mappings(struct proc *p) 1092 { 1093 struct vmspace *vmspace; 1094 struct sysentvec *sv; 1095 1096 vmspace = p->p_vmspace; 1097 if (refcount_load(&vmspace->vm_refcnt) != 1) 1098 return; 1099 1100 sv = p->p_sysent; 1101 if (sv->sv_shared_page_obj == NULL) 1102 return; 1103 1104 pmap_remove(vmspace_pmap(vmspace), sv->sv_shared_page_base, 1105 sv->sv_shared_page_base + sv->sv_shared_page_len); 1106 } 1107 1108 /* 1109 * Run down the current address space and install a new one. Map the shared 1110 * page. 1111 */ 1112 int 1113 exec_new_vmspace(struct image_params *imgp, struct sysentvec *sv) 1114 { 1115 int error; 1116 struct proc *p = imgp->proc; 1117 struct vmspace *vmspace = p->p_vmspace; 1118 struct thread *td = curthread; 1119 vm_object_t obj; 1120 vm_offset_t sv_minuser; 1121 vm_map_t map; 1122 1123 imgp->vmspace_destroyed = true; 1124 imgp->sysent = sv; 1125 1126 if (p->p_sysent->sv_onexec_old != NULL) 1127 p->p_sysent->sv_onexec_old(td); 1128 itimers_exec(p); 1129 1130 EVENTHANDLER_DIRECT_INVOKE(process_exec, p, imgp); 1131 1132 /* 1133 * Blow away entire process VM, if address space not shared, 1134 * otherwise, create a new VM space so that other threads are 1135 * not disrupted 1136 */ 1137 map = &vmspace->vm_map; 1138 if (map_at_zero) 1139 sv_minuser = sv->sv_minuser; 1140 else 1141 sv_minuser = MAX(sv->sv_minuser, PAGE_SIZE); 1142 if (refcount_load(&vmspace->vm_refcnt) == 1 && 1143 vm_map_min(map) == sv_minuser && 1144 vm_map_max(map) == sv->sv_maxuser && 1145 cpu_exec_vmspace_reuse(p, map)) { 1146 exec_free_abi_mappings(p); 1147 shmexit(vmspace); 1148 pmap_remove_pages(vmspace_pmap(vmspace)); 1149 vm_map_remove(map, vm_map_min(map), vm_map_max(map)); 1150 /* 1151 * An exec terminates mlockall(MCL_FUTURE). 1152 * ASLR and W^X states must be re-evaluated. 1153 */ 1154 vm_map_lock(map); 1155 vm_map_modflags(map, 0, MAP_WIREFUTURE | MAP_ASLR | 1156 MAP_ASLR_IGNSTART | MAP_ASLR_STACK | MAP_WXORX); 1157 vm_map_unlock(map); 1158 } else { 1159 error = vmspace_exec(p, sv_minuser, sv->sv_maxuser); 1160 if (error) 1161 return (error); 1162 vmspace = p->p_vmspace; 1163 map = &vmspace->vm_map; 1164 } 1165 map->flags |= imgp->map_flags; 1166 1167 /* Map a shared page */ 1168 obj = sv->sv_shared_page_obj; 1169 if (obj != NULL) { 1170 vm_object_reference(obj); 1171 error = vm_map_fixed(map, obj, 0, 1172 sv->sv_shared_page_base, sv->sv_shared_page_len, 1173 VM_PROT_READ | VM_PROT_EXECUTE, 1174 VM_PROT_READ | VM_PROT_EXECUTE, 1175 MAP_INHERIT_SHARE | MAP_ACC_NO_CHARGE); 1176 if (error != KERN_SUCCESS) { 1177 vm_object_deallocate(obj); 1178 return (vm_mmap_to_errno(error)); 1179 } 1180 } 1181 1182 return (sv->sv_onexec != NULL ? sv->sv_onexec(p, imgp) : 0); 1183 } 1184 1185 /* 1186 * Compute the stack size limit and map the main process stack. 1187 */ 1188 int 1189 exec_map_stack(struct image_params *imgp) 1190 { 1191 struct rlimit rlim_stack; 1192 struct sysentvec *sv; 1193 struct proc *p; 1194 vm_map_t map; 1195 struct vmspace *vmspace; 1196 vm_offset_t stack_addr, stack_top; 1197 u_long ssiz; 1198 int error, find_space, stack_off; 1199 vm_prot_t stack_prot; 1200 1201 p = imgp->proc; 1202 sv = p->p_sysent; 1203 1204 if (imgp->stack_sz != 0) { 1205 ssiz = trunc_page(imgp->stack_sz); 1206 PROC_LOCK(p); 1207 lim_rlimit_proc(p, RLIMIT_STACK, &rlim_stack); 1208 PROC_UNLOCK(p); 1209 if (ssiz > rlim_stack.rlim_max) 1210 ssiz = rlim_stack.rlim_max; 1211 if (ssiz > rlim_stack.rlim_cur) { 1212 rlim_stack.rlim_cur = ssiz; 1213 kern_setrlimit(curthread, RLIMIT_STACK, &rlim_stack); 1214 } 1215 } else if (sv->sv_maxssiz != NULL) { 1216 ssiz = *sv->sv_maxssiz; 1217 } else { 1218 ssiz = maxssiz; 1219 } 1220 1221 vmspace = p->p_vmspace; 1222 map = &vmspace->vm_map; 1223 1224 stack_prot = sv->sv_shared_page_obj != NULL && imgp->stack_prot != 0 ? 1225 imgp->stack_prot : sv->sv_stackprot; 1226 if ((map->flags & MAP_ASLR_STACK) != 0) { 1227 stack_addr = round_page((vm_offset_t)p->p_vmspace->vm_daddr + 1228 lim_max(curthread, RLIMIT_DATA)); 1229 find_space = VMFS_ANY_SPACE; 1230 } else { 1231 stack_addr = sv->sv_usrstack - ssiz; 1232 find_space = VMFS_NO_SPACE; 1233 } 1234 error = vm_map_find(map, NULL, 0, &stack_addr, (vm_size_t)ssiz, 1235 sv->sv_usrstack, find_space, stack_prot, VM_PROT_ALL, 1236 MAP_STACK_GROWS_DOWN); 1237 if (error != KERN_SUCCESS) { 1238 uprintf("exec_new_vmspace: mapping stack size %#jx prot %#x " 1239 "failed, mach error %d errno %d\n", (uintmax_t)ssiz, 1240 stack_prot, error, vm_mmap_to_errno(error)); 1241 return (vm_mmap_to_errno(error)); 1242 } 1243 1244 stack_top = stack_addr + ssiz; 1245 if ((map->flags & MAP_ASLR_STACK) != 0) { 1246 /* Randomize within the first page of the stack. */ 1247 arc4rand(&stack_off, sizeof(stack_off), 0); 1248 stack_top -= rounddown2(stack_off & PAGE_MASK, sizeof(void *)); 1249 } 1250 1251 /* 1252 * vm_ssize and vm_maxsaddr are somewhat antiquated concepts, but they 1253 * are still used to enforce the stack rlimit on the process stack. 1254 */ 1255 vmspace->vm_maxsaddr = (char *)stack_addr; 1256 vmspace->vm_stacktop = stack_top; 1257 vmspace->vm_ssize = sgrowsiz >> PAGE_SHIFT; 1258 1259 return (0); 1260 } 1261 1262 /* 1263 * Copy out argument and environment strings from the old process address 1264 * space into the temporary string buffer. 1265 */ 1266 int 1267 exec_copyin_args(struct image_args *args, const char *fname, 1268 enum uio_seg segflg, char **argv, char **envv) 1269 { 1270 u_long arg, env; 1271 int error; 1272 1273 bzero(args, sizeof(*args)); 1274 if (argv == NULL) 1275 return (EFAULT); 1276 1277 /* 1278 * Allocate demand-paged memory for the file name, argument, and 1279 * environment strings. 1280 */ 1281 error = exec_alloc_args(args); 1282 if (error != 0) 1283 return (error); 1284 1285 /* 1286 * Copy the file name. 1287 */ 1288 error = exec_args_add_fname(args, fname, segflg); 1289 if (error != 0) 1290 goto err_exit; 1291 1292 /* 1293 * extract arguments first 1294 */ 1295 for (;;) { 1296 error = fueword(argv++, &arg); 1297 if (error == -1) { 1298 error = EFAULT; 1299 goto err_exit; 1300 } 1301 if (arg == 0) 1302 break; 1303 error = exec_args_add_arg(args, (char *)(uintptr_t)arg, 1304 UIO_USERSPACE); 1305 if (error != 0) 1306 goto err_exit; 1307 } 1308 1309 /* 1310 * extract environment strings 1311 */ 1312 if (envv) { 1313 for (;;) { 1314 error = fueword(envv++, &env); 1315 if (error == -1) { 1316 error = EFAULT; 1317 goto err_exit; 1318 } 1319 if (env == 0) 1320 break; 1321 error = exec_args_add_env(args, 1322 (char *)(uintptr_t)env, UIO_USERSPACE); 1323 if (error != 0) 1324 goto err_exit; 1325 } 1326 } 1327 1328 return (0); 1329 1330 err_exit: 1331 exec_free_args(args); 1332 return (error); 1333 } 1334 1335 struct exec_args_kva { 1336 vm_offset_t addr; 1337 u_int gen; 1338 SLIST_ENTRY(exec_args_kva) next; 1339 }; 1340 1341 DPCPU_DEFINE_STATIC(struct exec_args_kva *, exec_args_kva); 1342 1343 static SLIST_HEAD(, exec_args_kva) exec_args_kva_freelist; 1344 static struct mtx exec_args_kva_mtx; 1345 static u_int exec_args_gen; 1346 1347 static void 1348 exec_prealloc_args_kva(void *arg __unused) 1349 { 1350 struct exec_args_kva *argkva; 1351 u_int i; 1352 1353 SLIST_INIT(&exec_args_kva_freelist); 1354 mtx_init(&exec_args_kva_mtx, "exec args kva", NULL, MTX_DEF); 1355 for (i = 0; i < exec_map_entries; i++) { 1356 argkva = malloc(sizeof(*argkva), M_PARGS, M_WAITOK); 1357 argkva->addr = kmap_alloc_wait(exec_map, exec_map_entry_size); 1358 argkva->gen = exec_args_gen; 1359 SLIST_INSERT_HEAD(&exec_args_kva_freelist, argkva, next); 1360 } 1361 } 1362 SYSINIT(exec_args_kva, SI_SUB_EXEC, SI_ORDER_ANY, exec_prealloc_args_kva, NULL); 1363 1364 static vm_offset_t 1365 exec_alloc_args_kva(void **cookie) 1366 { 1367 struct exec_args_kva *argkva; 1368 1369 argkva = (void *)atomic_readandclear_ptr( 1370 (uintptr_t *)DPCPU_PTR(exec_args_kva)); 1371 if (argkva == NULL) { 1372 mtx_lock(&exec_args_kva_mtx); 1373 while ((argkva = SLIST_FIRST(&exec_args_kva_freelist)) == NULL) 1374 (void)mtx_sleep(&exec_args_kva_freelist, 1375 &exec_args_kva_mtx, 0, "execkva", 0); 1376 SLIST_REMOVE_HEAD(&exec_args_kva_freelist, next); 1377 mtx_unlock(&exec_args_kva_mtx); 1378 } 1379 kasan_mark((void *)argkva->addr, exec_map_entry_size, 1380 exec_map_entry_size, 0); 1381 *(struct exec_args_kva **)cookie = argkva; 1382 return (argkva->addr); 1383 } 1384 1385 static void 1386 exec_release_args_kva(struct exec_args_kva *argkva, u_int gen) 1387 { 1388 vm_offset_t base; 1389 1390 base = argkva->addr; 1391 kasan_mark((void *)argkva->addr, 0, exec_map_entry_size, 1392 KASAN_EXEC_ARGS_FREED); 1393 if (argkva->gen != gen) { 1394 (void)vm_map_madvise(exec_map, base, base + exec_map_entry_size, 1395 MADV_FREE); 1396 argkva->gen = gen; 1397 } 1398 if (!atomic_cmpset_ptr((uintptr_t *)DPCPU_PTR(exec_args_kva), 1399 (uintptr_t)NULL, (uintptr_t)argkva)) { 1400 mtx_lock(&exec_args_kva_mtx); 1401 SLIST_INSERT_HEAD(&exec_args_kva_freelist, argkva, next); 1402 wakeup_one(&exec_args_kva_freelist); 1403 mtx_unlock(&exec_args_kva_mtx); 1404 } 1405 } 1406 1407 static void 1408 exec_free_args_kva(void *cookie) 1409 { 1410 1411 exec_release_args_kva(cookie, exec_args_gen); 1412 } 1413 1414 static void 1415 exec_args_kva_lowmem(void *arg __unused) 1416 { 1417 SLIST_HEAD(, exec_args_kva) head; 1418 struct exec_args_kva *argkva; 1419 u_int gen; 1420 int i; 1421 1422 gen = atomic_fetchadd_int(&exec_args_gen, 1) + 1; 1423 1424 /* 1425 * Force an madvise of each KVA range. Any currently allocated ranges 1426 * will have MADV_FREE applied once they are freed. 1427 */ 1428 SLIST_INIT(&head); 1429 mtx_lock(&exec_args_kva_mtx); 1430 SLIST_SWAP(&head, &exec_args_kva_freelist, exec_args_kva); 1431 mtx_unlock(&exec_args_kva_mtx); 1432 while ((argkva = SLIST_FIRST(&head)) != NULL) { 1433 SLIST_REMOVE_HEAD(&head, next); 1434 exec_release_args_kva(argkva, gen); 1435 } 1436 1437 CPU_FOREACH(i) { 1438 argkva = (void *)atomic_readandclear_ptr( 1439 (uintptr_t *)DPCPU_ID_PTR(i, exec_args_kva)); 1440 if (argkva != NULL) 1441 exec_release_args_kva(argkva, gen); 1442 } 1443 } 1444 EVENTHANDLER_DEFINE(vm_lowmem, exec_args_kva_lowmem, NULL, 1445 EVENTHANDLER_PRI_ANY); 1446 1447 /* 1448 * Allocate temporary demand-paged, zero-filled memory for the file name, 1449 * argument, and environment strings. 1450 */ 1451 int 1452 exec_alloc_args(struct image_args *args) 1453 { 1454 1455 args->buf = (char *)exec_alloc_args_kva(&args->bufkva); 1456 return (0); 1457 } 1458 1459 void 1460 exec_free_args(struct image_args *args) 1461 { 1462 1463 if (args->buf != NULL) { 1464 exec_free_args_kva(args->bufkva); 1465 args->buf = NULL; 1466 } 1467 if (args->fname_buf != NULL) { 1468 free(args->fname_buf, M_TEMP); 1469 args->fname_buf = NULL; 1470 } 1471 } 1472 1473 /* 1474 * A set to functions to fill struct image args. 1475 * 1476 * NOTE: exec_args_add_fname() must be called (possibly with a NULL 1477 * fname) before the other functions. All exec_args_add_arg() calls must 1478 * be made before any exec_args_add_env() calls. exec_args_adjust_args() 1479 * may be called any time after exec_args_add_fname(). 1480 * 1481 * exec_args_add_fname() - install path to be executed 1482 * exec_args_add_arg() - append an argument string 1483 * exec_args_add_env() - append an env string 1484 * exec_args_adjust_args() - adjust location of the argument list to 1485 * allow new arguments to be prepended 1486 */ 1487 int 1488 exec_args_add_fname(struct image_args *args, const char *fname, 1489 enum uio_seg segflg) 1490 { 1491 int error; 1492 size_t length; 1493 1494 KASSERT(args->fname == NULL, ("fname already appended")); 1495 KASSERT(args->endp == NULL, ("already appending to args")); 1496 1497 if (fname != NULL) { 1498 args->fname = args->buf; 1499 error = segflg == UIO_SYSSPACE ? 1500 copystr(fname, args->fname, PATH_MAX, &length) : 1501 copyinstr(fname, args->fname, PATH_MAX, &length); 1502 if (error != 0) 1503 return (error == ENAMETOOLONG ? E2BIG : error); 1504 } else 1505 length = 0; 1506 1507 /* Set up for _arg_*()/_env_*() */ 1508 args->endp = args->buf + length; 1509 /* begin_argv must be set and kept updated */ 1510 args->begin_argv = args->endp; 1511 KASSERT(exec_map_entry_size - length >= ARG_MAX, 1512 ("too little space remaining for arguments %zu < %zu", 1513 exec_map_entry_size - length, (size_t)ARG_MAX)); 1514 args->stringspace = ARG_MAX; 1515 1516 return (0); 1517 } 1518 1519 static int 1520 exec_args_add_str(struct image_args *args, const char *str, 1521 enum uio_seg segflg, int *countp) 1522 { 1523 int error; 1524 size_t length; 1525 1526 KASSERT(args->endp != NULL, ("endp not initialized")); 1527 KASSERT(args->begin_argv != NULL, ("begin_argp not initialized")); 1528 1529 error = (segflg == UIO_SYSSPACE) ? 1530 copystr(str, args->endp, args->stringspace, &length) : 1531 copyinstr(str, args->endp, args->stringspace, &length); 1532 if (error != 0) 1533 return (error == ENAMETOOLONG ? E2BIG : error); 1534 args->stringspace -= length; 1535 args->endp += length; 1536 (*countp)++; 1537 1538 return (0); 1539 } 1540 1541 int 1542 exec_args_add_arg(struct image_args *args, const char *argp, 1543 enum uio_seg segflg) 1544 { 1545 1546 KASSERT(args->envc == 0, ("appending args after env")); 1547 1548 return (exec_args_add_str(args, argp, segflg, &args->argc)); 1549 } 1550 1551 int 1552 exec_args_add_env(struct image_args *args, const char *envp, 1553 enum uio_seg segflg) 1554 { 1555 1556 if (args->envc == 0) 1557 args->begin_envv = args->endp; 1558 1559 return (exec_args_add_str(args, envp, segflg, &args->envc)); 1560 } 1561 1562 int 1563 exec_args_adjust_args(struct image_args *args, size_t consume, ssize_t extend) 1564 { 1565 ssize_t offset; 1566 1567 KASSERT(args->endp != NULL, ("endp not initialized")); 1568 KASSERT(args->begin_argv != NULL, ("begin_argp not initialized")); 1569 1570 offset = extend - consume; 1571 if (args->stringspace < offset) 1572 return (E2BIG); 1573 memmove(args->begin_argv + extend, args->begin_argv + consume, 1574 args->endp - args->begin_argv + consume); 1575 if (args->envc > 0) 1576 args->begin_envv += offset; 1577 args->endp += offset; 1578 args->stringspace -= offset; 1579 return (0); 1580 } 1581 1582 char * 1583 exec_args_get_begin_envv(struct image_args *args) 1584 { 1585 1586 KASSERT(args->endp != NULL, ("endp not initialized")); 1587 1588 if (args->envc > 0) 1589 return (args->begin_envv); 1590 return (args->endp); 1591 } 1592 1593 /* 1594 * Copy strings out to the new process address space, constructing new arg 1595 * and env vector tables. Return a pointer to the base so that it can be used 1596 * as the initial stack pointer. 1597 */ 1598 int 1599 exec_copyout_strings(struct image_params *imgp, uintptr_t *stack_base) 1600 { 1601 int argc, envc; 1602 char **vectp; 1603 char *stringp; 1604 uintptr_t destp, ustringp; 1605 struct ps_strings *arginfo; 1606 struct proc *p; 1607 struct sysentvec *sysent; 1608 size_t execpath_len; 1609 int error, szsigcode; 1610 char canary[sizeof(long) * 8]; 1611 1612 p = imgp->proc; 1613 sysent = p->p_sysent; 1614 1615 destp = PROC_PS_STRINGS(p); 1616 arginfo = imgp->ps_strings = (void *)destp; 1617 1618 /* 1619 * Install sigcode. 1620 */ 1621 if (sysent->sv_sigcode_base == 0 && sysent->sv_szsigcode != NULL) { 1622 szsigcode = *(sysent->sv_szsigcode); 1623 destp -= szsigcode; 1624 destp = rounddown2(destp, sizeof(void *)); 1625 error = copyout(sysent->sv_sigcode, (void *)destp, szsigcode); 1626 if (error != 0) 1627 return (error); 1628 } 1629 1630 /* 1631 * Copy the image path for the rtld. 1632 */ 1633 if (imgp->execpath != NULL && imgp->auxargs != NULL) { 1634 execpath_len = strlen(imgp->execpath) + 1; 1635 destp -= execpath_len; 1636 destp = rounddown2(destp, sizeof(void *)); 1637 imgp->execpathp = (void *)destp; 1638 error = copyout(imgp->execpath, imgp->execpathp, execpath_len); 1639 if (error != 0) 1640 return (error); 1641 } 1642 1643 /* 1644 * Prepare the canary for SSP. 1645 */ 1646 arc4rand(canary, sizeof(canary), 0); 1647 destp -= sizeof(canary); 1648 imgp->canary = (void *)destp; 1649 error = copyout(canary, imgp->canary, sizeof(canary)); 1650 if (error != 0) 1651 return (error); 1652 imgp->canarylen = sizeof(canary); 1653 1654 /* 1655 * Prepare the pagesizes array. 1656 */ 1657 imgp->pagesizeslen = sizeof(pagesizes[0]) * MAXPAGESIZES; 1658 destp -= imgp->pagesizeslen; 1659 destp = rounddown2(destp, sizeof(void *)); 1660 imgp->pagesizes = (void *)destp; 1661 error = copyout(pagesizes, imgp->pagesizes, imgp->pagesizeslen); 1662 if (error != 0) 1663 return (error); 1664 1665 /* 1666 * Allocate room for the argument and environment strings. 1667 */ 1668 destp -= ARG_MAX - imgp->args->stringspace; 1669 destp = rounddown2(destp, sizeof(void *)); 1670 ustringp = destp; 1671 1672 if (imgp->auxargs) { 1673 /* 1674 * Allocate room on the stack for the ELF auxargs 1675 * array. It has up to AT_COUNT entries. 1676 */ 1677 destp -= AT_COUNT * sizeof(Elf_Auxinfo); 1678 destp = rounddown2(destp, sizeof(void *)); 1679 } 1680 1681 vectp = (char **)destp; 1682 1683 /* 1684 * Allocate room for the argv[] and env vectors including the 1685 * terminating NULL pointers. 1686 */ 1687 vectp -= imgp->args->argc + 1 + imgp->args->envc + 1; 1688 1689 /* 1690 * vectp also becomes our initial stack base 1691 */ 1692 *stack_base = (uintptr_t)vectp; 1693 1694 stringp = imgp->args->begin_argv; 1695 argc = imgp->args->argc; 1696 envc = imgp->args->envc; 1697 1698 /* 1699 * Copy out strings - arguments and environment. 1700 */ 1701 error = copyout(stringp, (void *)ustringp, 1702 ARG_MAX - imgp->args->stringspace); 1703 if (error != 0) 1704 return (error); 1705 1706 /* 1707 * Fill in "ps_strings" struct for ps, w, etc. 1708 */ 1709 imgp->argv = vectp; 1710 if (suword(&arginfo->ps_argvstr, (long)(intptr_t)vectp) != 0 || 1711 suword32(&arginfo->ps_nargvstr, argc) != 0) 1712 return (EFAULT); 1713 1714 /* 1715 * Fill in argument portion of vector table. 1716 */ 1717 for (; argc > 0; --argc) { 1718 if (suword(vectp++, ustringp) != 0) 1719 return (EFAULT); 1720 while (*stringp++ != 0) 1721 ustringp++; 1722 ustringp++; 1723 } 1724 1725 /* a null vector table pointer separates the argp's from the envp's */ 1726 if (suword(vectp++, 0) != 0) 1727 return (EFAULT); 1728 1729 imgp->envv = vectp; 1730 if (suword(&arginfo->ps_envstr, (long)(intptr_t)vectp) != 0 || 1731 suword32(&arginfo->ps_nenvstr, envc) != 0) 1732 return (EFAULT); 1733 1734 /* 1735 * Fill in environment portion of vector table. 1736 */ 1737 for (; envc > 0; --envc) { 1738 if (suword(vectp++, ustringp) != 0) 1739 return (EFAULT); 1740 while (*stringp++ != 0) 1741 ustringp++; 1742 ustringp++; 1743 } 1744 1745 /* end of vector table is a null pointer */ 1746 if (suword(vectp, 0) != 0) 1747 return (EFAULT); 1748 1749 if (imgp->auxargs) { 1750 vectp++; 1751 error = imgp->sysent->sv_copyout_auxargs(imgp, 1752 (uintptr_t)vectp); 1753 if (error != 0) 1754 return (error); 1755 } 1756 1757 return (0); 1758 } 1759 1760 /* 1761 * Check permissions of file to execute. 1762 * Called with imgp->vp locked. 1763 * Return 0 for success or error code on failure. 1764 */ 1765 int 1766 exec_check_permissions(struct image_params *imgp) 1767 { 1768 struct vnode *vp = imgp->vp; 1769 struct vattr *attr = imgp->attr; 1770 struct thread *td; 1771 int error; 1772 1773 td = curthread; 1774 1775 /* Get file attributes */ 1776 error = VOP_GETATTR(vp, attr, td->td_ucred); 1777 if (error) 1778 return (error); 1779 1780 #ifdef MAC 1781 error = mac_vnode_check_exec(td->td_ucred, imgp->vp, imgp); 1782 if (error) 1783 return (error); 1784 #endif 1785 1786 /* 1787 * 1) Check if file execution is disabled for the filesystem that 1788 * this file resides on. 1789 * 2) Ensure that at least one execute bit is on. Otherwise, a 1790 * privileged user will always succeed, and we don't want this 1791 * to happen unless the file really is executable. 1792 * 3) Ensure that the file is a regular file. 1793 */ 1794 if ((vp->v_mount->mnt_flag & MNT_NOEXEC) || 1795 (attr->va_mode & (S_IXUSR | S_IXGRP | S_IXOTH)) == 0 || 1796 (attr->va_type != VREG)) 1797 return (EACCES); 1798 1799 /* 1800 * Zero length files can't be exec'd 1801 */ 1802 if (attr->va_size == 0) 1803 return (ENOEXEC); 1804 1805 /* 1806 * Check for execute permission to file based on current credentials. 1807 */ 1808 error = VOP_ACCESS(vp, VEXEC, td->td_ucred, td); 1809 if (error) 1810 return (error); 1811 1812 /* 1813 * Check number of open-for-writes on the file and deny execution 1814 * if there are any. 1815 * 1816 * Add a text reference now so no one can write to the 1817 * executable while we're activating it. 1818 * 1819 * Remember if this was set before and unset it in case this is not 1820 * actually an executable image. 1821 */ 1822 error = VOP_SET_TEXT(vp); 1823 if (error != 0) 1824 return (error); 1825 imgp->textset = true; 1826 1827 /* 1828 * Call filesystem specific open routine (which does nothing in the 1829 * general case). 1830 */ 1831 error = VOP_OPEN(vp, FREAD, td->td_ucred, td, NULL); 1832 if (error == 0) 1833 imgp->opened = true; 1834 return (error); 1835 } 1836 1837 /* 1838 * Exec handler registration 1839 */ 1840 int 1841 exec_register(const struct execsw *execsw_arg) 1842 { 1843 const struct execsw **es, **xs, **newexecsw; 1844 u_int count = 2; /* New slot and trailing NULL */ 1845 1846 if (execsw) 1847 for (es = execsw; *es; es++) 1848 count++; 1849 newexecsw = malloc(count * sizeof(*es), M_TEMP, M_WAITOK); 1850 xs = newexecsw; 1851 if (execsw) 1852 for (es = execsw; *es; es++) 1853 *xs++ = *es; 1854 *xs++ = execsw_arg; 1855 *xs = NULL; 1856 if (execsw) 1857 free(execsw, M_TEMP); 1858 execsw = newexecsw; 1859 return (0); 1860 } 1861 1862 int 1863 exec_unregister(const struct execsw *execsw_arg) 1864 { 1865 const struct execsw **es, **xs, **newexecsw; 1866 int count = 1; 1867 1868 if (execsw == NULL) 1869 panic("unregister with no handlers left?\n"); 1870 1871 for (es = execsw; *es; es++) { 1872 if (*es == execsw_arg) 1873 break; 1874 } 1875 if (*es == NULL) 1876 return (ENOENT); 1877 for (es = execsw; *es; es++) 1878 if (*es != execsw_arg) 1879 count++; 1880 newexecsw = malloc(count * sizeof(*es), M_TEMP, M_WAITOK); 1881 xs = newexecsw; 1882 for (es = execsw; *es; es++) 1883 if (*es != execsw_arg) 1884 *xs++ = *es; 1885 *xs = NULL; 1886 if (execsw) 1887 free(execsw, M_TEMP); 1888 execsw = newexecsw; 1889 return (0); 1890 } 1891 1892 /* 1893 * Write out a core segment to the compression stream. 1894 */ 1895 static int 1896 compress_chunk(struct coredump_params *cp, char *base, char *buf, size_t len) 1897 { 1898 size_t chunk_len; 1899 int error; 1900 1901 while (len > 0) { 1902 chunk_len = MIN(len, CORE_BUF_SIZE); 1903 1904 /* 1905 * We can get EFAULT error here. 1906 * In that case zero out the current chunk of the segment. 1907 */ 1908 error = copyin(base, buf, chunk_len); 1909 if (error != 0) 1910 bzero(buf, chunk_len); 1911 error = compressor_write(cp->comp, buf, chunk_len); 1912 if (error != 0) 1913 break; 1914 base += chunk_len; 1915 len -= chunk_len; 1916 } 1917 return (error); 1918 } 1919 1920 int 1921 core_write(struct coredump_params *cp, const void *base, size_t len, 1922 off_t offset, enum uio_seg seg, size_t *resid) 1923 { 1924 1925 return (vn_rdwr_inchunks(UIO_WRITE, cp->vp, __DECONST(void *, base), 1926 len, offset, seg, IO_UNIT | IO_DIRECT | IO_RANGELOCKED, 1927 cp->active_cred, cp->file_cred, resid, cp->td)); 1928 } 1929 1930 int 1931 core_output(char *base, size_t len, off_t offset, struct coredump_params *cp, 1932 void *tmpbuf) 1933 { 1934 vm_map_t map; 1935 struct mount *mp; 1936 size_t resid, runlen; 1937 int error; 1938 bool success; 1939 1940 KASSERT((uintptr_t)base % PAGE_SIZE == 0, 1941 ("%s: user address %p is not page-aligned", __func__, base)); 1942 1943 if (cp->comp != NULL) 1944 return (compress_chunk(cp, base, tmpbuf, len)); 1945 1946 map = &cp->td->td_proc->p_vmspace->vm_map; 1947 for (; len > 0; base += runlen, offset += runlen, len -= runlen) { 1948 /* 1949 * Attempt to page in all virtual pages in the range. If a 1950 * virtual page is not backed by the pager, it is represented as 1951 * a hole in the file. This can occur with zero-filled 1952 * anonymous memory or truncated files, for example. 1953 */ 1954 for (runlen = 0; runlen < len; runlen += PAGE_SIZE) { 1955 if (core_dump_can_intr && curproc_sigkilled()) 1956 return (EINTR); 1957 error = vm_fault(map, (uintptr_t)base + runlen, 1958 VM_PROT_READ, VM_FAULT_NOFILL, NULL); 1959 if (runlen == 0) 1960 success = error == KERN_SUCCESS; 1961 else if ((error == KERN_SUCCESS) != success) 1962 break; 1963 } 1964 1965 if (success) { 1966 error = core_write(cp, base, runlen, offset, 1967 UIO_USERSPACE, &resid); 1968 if (error != 0) { 1969 if (error != EFAULT) 1970 break; 1971 1972 /* 1973 * EFAULT may be returned if the user mapping 1974 * could not be accessed, e.g., because a mapped 1975 * file has been truncated. Skip the page if no 1976 * progress was made, to protect against a 1977 * hypothetical scenario where vm_fault() was 1978 * successful but core_write() returns EFAULT 1979 * anyway. 1980 */ 1981 runlen -= resid; 1982 if (runlen == 0) { 1983 success = false; 1984 runlen = PAGE_SIZE; 1985 } 1986 } 1987 } 1988 if (!success) { 1989 error = vn_start_write(cp->vp, &mp, V_WAIT); 1990 if (error != 0) 1991 break; 1992 vn_lock(cp->vp, LK_EXCLUSIVE | LK_RETRY); 1993 error = vn_truncate_locked(cp->vp, offset + runlen, 1994 false, cp->td->td_ucred); 1995 VOP_UNLOCK(cp->vp); 1996 vn_finished_write(mp); 1997 if (error != 0) 1998 break; 1999 } 2000 } 2001 return (error); 2002 } 2003 2004 /* 2005 * Drain into a core file. 2006 */ 2007 int 2008 sbuf_drain_core_output(void *arg, const char *data, int len) 2009 { 2010 struct coredump_params *cp; 2011 struct proc *p; 2012 int error, locked; 2013 2014 cp = arg; 2015 p = cp->td->td_proc; 2016 2017 /* 2018 * Some kern_proc out routines that print to this sbuf may 2019 * call us with the process lock held. Draining with the 2020 * non-sleepable lock held is unsafe. The lock is needed for 2021 * those routines when dumping a live process. In our case we 2022 * can safely release the lock before draining and acquire 2023 * again after. 2024 */ 2025 locked = PROC_LOCKED(p); 2026 if (locked) 2027 PROC_UNLOCK(p); 2028 if (cp->comp != NULL) 2029 error = compressor_write(cp->comp, __DECONST(char *, data), 2030 len); 2031 else 2032 error = core_write(cp, __DECONST(void *, data), len, cp->offset, 2033 UIO_SYSSPACE, NULL); 2034 if (locked) 2035 PROC_LOCK(p); 2036 if (error != 0) 2037 return (-error); 2038 cp->offset += len; 2039 return (len); 2040 } 2041