1 /*- 2 * Copyright (c) 1993, David Greenman 3 * All rights reserved. 4 * 5 * Redistribution and use in source and binary forms, with or without 6 * modification, are permitted provided that the following conditions 7 * are met: 8 * 1. Redistributions of source code must retain the above copyright 9 * notice, this list of conditions and the following disclaimer. 10 * 2. Redistributions in binary form must reproduce the above copyright 11 * notice, this list of conditions and the following disclaimer in the 12 * documentation and/or other materials provided with the distribution. 13 * 14 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND 15 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 16 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 17 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE 18 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 19 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 20 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 21 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 22 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 23 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 24 * SUCH DAMAGE. 25 */ 26 27 #include <sys/cdefs.h> 28 __FBSDID("$FreeBSD$"); 29 30 #include "opt_hwpmc_hooks.h" 31 #include "opt_kdtrace.h" 32 #include "opt_ktrace.h" 33 #include "opt_vm.h" 34 35 #include <sys/param.h> 36 #include <sys/systm.h> 37 #include <sys/eventhandler.h> 38 #include <sys/lock.h> 39 #include <sys/mutex.h> 40 #include <sys/sysproto.h> 41 #include <sys/signalvar.h> 42 #include <sys/kernel.h> 43 #include <sys/mount.h> 44 #include <sys/filedesc.h> 45 #include <sys/fcntl.h> 46 #include <sys/acct.h> 47 #include <sys/exec.h> 48 #include <sys/imgact.h> 49 #include <sys/imgact_elf.h> 50 #include <sys/wait.h> 51 #include <sys/malloc.h> 52 #include <sys/priv.h> 53 #include <sys/proc.h> 54 #include <sys/pioctl.h> 55 #include <sys/namei.h> 56 #include <sys/resourcevar.h> 57 #include <sys/sdt.h> 58 #include <sys/sf_buf.h> 59 #include <sys/syscallsubr.h> 60 #include <sys/sysent.h> 61 #include <sys/shm.h> 62 #include <sys/sysctl.h> 63 #include <sys/vnode.h> 64 #include <sys/stat.h> 65 #ifdef KTRACE 66 #include <sys/ktrace.h> 67 #endif 68 69 #include <vm/vm.h> 70 #include <vm/vm_param.h> 71 #include <vm/pmap.h> 72 #include <vm/vm_page.h> 73 #include <vm/vm_map.h> 74 #include <vm/vm_kern.h> 75 #include <vm/vm_extern.h> 76 #include <vm/vm_object.h> 77 #include <vm/vm_pager.h> 78 79 #ifdef HWPMC_HOOKS 80 #include <sys/pmckern.h> 81 #endif 82 83 #include <machine/reg.h> 84 85 #include <security/audit/audit.h> 86 #include <security/mac/mac_framework.h> 87 88 #ifdef KDTRACE_HOOKS 89 #include <sys/dtrace_bsd.h> 90 dtrace_execexit_func_t dtrace_fasttrap_exec; 91 #endif 92 93 SDT_PROVIDER_DECLARE(proc); 94 SDT_PROBE_DEFINE(proc, kernel, , exec); 95 SDT_PROBE_ARGTYPE(proc, kernel, , exec, 0, "char *"); 96 SDT_PROBE_DEFINE(proc, kernel, , exec_failure); 97 SDT_PROBE_ARGTYPE(proc, kernel, , exec_failure, 0, "int"); 98 SDT_PROBE_DEFINE(proc, kernel, , exec_success); 99 SDT_PROBE_ARGTYPE(proc, kernel, , exec_success, 0, "char *"); 100 101 MALLOC_DEFINE(M_PARGS, "proc-args", "Process arguments"); 102 103 static int sysctl_kern_ps_strings(SYSCTL_HANDLER_ARGS); 104 static int sysctl_kern_usrstack(SYSCTL_HANDLER_ARGS); 105 static int sysctl_kern_stackprot(SYSCTL_HANDLER_ARGS); 106 static int do_execve(struct thread *td, struct image_args *args, 107 struct mac *mac_p); 108 static void exec_free_args(struct image_args *); 109 110 /* XXX This should be vm_size_t. */ 111 SYSCTL_PROC(_kern, KERN_PS_STRINGS, ps_strings, CTLTYPE_ULONG|CTLFLAG_RD, 112 NULL, 0, sysctl_kern_ps_strings, "LU", ""); 113 114 /* XXX This should be vm_size_t. */ 115 SYSCTL_PROC(_kern, KERN_USRSTACK, usrstack, CTLTYPE_ULONG|CTLFLAG_RD, 116 NULL, 0, sysctl_kern_usrstack, "LU", ""); 117 118 SYSCTL_PROC(_kern, OID_AUTO, stackprot, CTLTYPE_INT|CTLFLAG_RD, 119 NULL, 0, sysctl_kern_stackprot, "I", ""); 120 121 u_long ps_arg_cache_limit = PAGE_SIZE / 16; 122 SYSCTL_ULONG(_kern, OID_AUTO, ps_arg_cache_limit, CTLFLAG_RW, 123 &ps_arg_cache_limit, 0, ""); 124 125 static int 126 sysctl_kern_ps_strings(SYSCTL_HANDLER_ARGS) 127 { 128 struct proc *p; 129 int error; 130 131 p = curproc; 132 #ifdef SCTL_MASK32 133 if (req->flags & SCTL_MASK32) { 134 unsigned int val; 135 val = (unsigned int)p->p_sysent->sv_psstrings; 136 error = SYSCTL_OUT(req, &val, sizeof(val)); 137 } else 138 #endif 139 error = SYSCTL_OUT(req, &p->p_sysent->sv_psstrings, 140 sizeof(p->p_sysent->sv_psstrings)); 141 return error; 142 } 143 144 static int 145 sysctl_kern_usrstack(SYSCTL_HANDLER_ARGS) 146 { 147 struct proc *p; 148 int error; 149 150 p = curproc; 151 #ifdef SCTL_MASK32 152 if (req->flags & SCTL_MASK32) { 153 unsigned int val; 154 val = (unsigned int)p->p_sysent->sv_usrstack; 155 error = SYSCTL_OUT(req, &val, sizeof(val)); 156 } else 157 #endif 158 error = SYSCTL_OUT(req, &p->p_sysent->sv_usrstack, 159 sizeof(p->p_sysent->sv_usrstack)); 160 return error; 161 } 162 163 static int 164 sysctl_kern_stackprot(SYSCTL_HANDLER_ARGS) 165 { 166 struct proc *p; 167 168 p = curproc; 169 return (SYSCTL_OUT(req, &p->p_sysent->sv_stackprot, 170 sizeof(p->p_sysent->sv_stackprot))); 171 } 172 173 /* 174 * Each of the items is a pointer to a `const struct execsw', hence the 175 * double pointer here. 176 */ 177 static const struct execsw **execsw; 178 179 #ifndef _SYS_SYSPROTO_H_ 180 struct execve_args { 181 char *fname; 182 char **argv; 183 char **envv; 184 }; 185 #endif 186 187 int 188 execve(td, uap) 189 struct thread *td; 190 struct execve_args /* { 191 char *fname; 192 char **argv; 193 char **envv; 194 } */ *uap; 195 { 196 int error; 197 struct image_args args; 198 199 error = exec_copyin_args(&args, uap->fname, UIO_USERSPACE, 200 uap->argv, uap->envv); 201 if (error == 0) 202 error = kern_execve(td, &args, NULL); 203 return (error); 204 } 205 206 #ifndef _SYS_SYSPROTO_H_ 207 struct fexecve_args { 208 int fd; 209 char **argv; 210 char **envv; 211 } 212 #endif 213 int 214 fexecve(struct thread *td, struct fexecve_args *uap) 215 { 216 int error; 217 struct image_args args; 218 219 error = exec_copyin_args(&args, NULL, UIO_SYSSPACE, 220 uap->argv, uap->envv); 221 if (error == 0) { 222 args.fd = uap->fd; 223 error = kern_execve(td, &args, NULL); 224 } 225 return (error); 226 } 227 228 #ifndef _SYS_SYSPROTO_H_ 229 struct __mac_execve_args { 230 char *fname; 231 char **argv; 232 char **envv; 233 struct mac *mac_p; 234 }; 235 #endif 236 237 int 238 __mac_execve(td, uap) 239 struct thread *td; 240 struct __mac_execve_args /* { 241 char *fname; 242 char **argv; 243 char **envv; 244 struct mac *mac_p; 245 } */ *uap; 246 { 247 #ifdef MAC 248 int error; 249 struct image_args args; 250 251 error = exec_copyin_args(&args, uap->fname, UIO_USERSPACE, 252 uap->argv, uap->envv); 253 if (error == 0) 254 error = kern_execve(td, &args, uap->mac_p); 255 return (error); 256 #else 257 return (ENOSYS); 258 #endif 259 } 260 261 /* 262 * XXX: kern_execve has the astonishing property of not always returning to 263 * the caller. If sufficiently bad things happen during the call to 264 * do_execve(), it can end up calling exit1(); as a result, callers must 265 * avoid doing anything which they might need to undo (e.g., allocating 266 * memory). 267 */ 268 int 269 kern_execve(td, args, mac_p) 270 struct thread *td; 271 struct image_args *args; 272 struct mac *mac_p; 273 { 274 struct proc *p = td->td_proc; 275 int error; 276 277 AUDIT_ARG_ARGV(args->begin_argv, args->argc, 278 args->begin_envv - args->begin_argv); 279 AUDIT_ARG_ENVV(args->begin_envv, args->envc, 280 args->endp - args->begin_envv); 281 if (p->p_flag & P_HADTHREADS) { 282 PROC_LOCK(p); 283 if (thread_single(SINGLE_BOUNDARY)) { 284 PROC_UNLOCK(p); 285 exec_free_args(args); 286 return (ERESTART); /* Try again later. */ 287 } 288 PROC_UNLOCK(p); 289 } 290 291 error = do_execve(td, args, mac_p); 292 293 if (p->p_flag & P_HADTHREADS) { 294 PROC_LOCK(p); 295 /* 296 * If success, we upgrade to SINGLE_EXIT state to 297 * force other threads to suicide. 298 */ 299 if (error == 0) 300 thread_single(SINGLE_EXIT); 301 else 302 thread_single_end(); 303 PROC_UNLOCK(p); 304 } 305 306 return (error); 307 } 308 309 /* 310 * In-kernel implementation of execve(). All arguments are assumed to be 311 * userspace pointers from the passed thread. 312 */ 313 static int 314 do_execve(td, args, mac_p) 315 struct thread *td; 316 struct image_args *args; 317 struct mac *mac_p; 318 { 319 struct proc *p = td->td_proc; 320 struct nameidata nd; 321 struct ucred *newcred = NULL, *oldcred; 322 struct uidinfo *euip; 323 register_t *stack_base; 324 int error, len = 0, i; 325 struct image_params image_params, *imgp; 326 struct vattr attr; 327 int (*img_first)(struct image_params *); 328 struct pargs *oldargs = NULL, *newargs = NULL; 329 struct sigacts *oldsigacts, *newsigacts; 330 #ifdef KTRACE 331 struct vnode *tracevp = NULL; 332 struct ucred *tracecred = NULL; 333 #endif 334 struct vnode *textvp = NULL, *binvp = NULL; 335 int credential_changing; 336 int vfslocked; 337 int textset; 338 #ifdef MAC 339 struct label *interpvplabel = NULL; 340 int will_transition; 341 #endif 342 #ifdef HWPMC_HOOKS 343 struct pmckern_procexec pe; 344 #endif 345 static const char fexecv_proc_title[] = "(fexecv)"; 346 347 vfslocked = 0; 348 imgp = &image_params; 349 350 /* 351 * Lock the process and set the P_INEXEC flag to indicate that 352 * it should be left alone until we're done here. This is 353 * necessary to avoid race conditions - e.g. in ptrace() - 354 * that might allow a local user to illicitly obtain elevated 355 * privileges. 356 */ 357 PROC_LOCK(p); 358 KASSERT((p->p_flag & P_INEXEC) == 0, 359 ("%s(): process already has P_INEXEC flag", __func__)); 360 p->p_flag |= P_INEXEC; 361 PROC_UNLOCK(p); 362 363 /* 364 * Initialize part of the common data 365 */ 366 imgp->proc = p; 367 imgp->execlabel = NULL; 368 imgp->attr = &attr; 369 imgp->entry_addr = 0; 370 imgp->vmspace_destroyed = 0; 371 imgp->interpreted = 0; 372 imgp->opened = 0; 373 imgp->interpreter_name = args->buf + PATH_MAX + ARG_MAX; 374 imgp->auxargs = NULL; 375 imgp->vp = NULL; 376 imgp->object = NULL; 377 imgp->firstpage = NULL; 378 imgp->ps_strings = 0; 379 imgp->auxarg_size = 0; 380 imgp->args = args; 381 imgp->execpath = imgp->freepath = NULL; 382 imgp->execpathp = 0; 383 384 #ifdef MAC 385 error = mac_execve_enter(imgp, mac_p); 386 if (error) 387 goto exec_fail; 388 #endif 389 390 imgp->image_header = NULL; 391 392 /* 393 * Translate the file name. namei() returns a vnode pointer 394 * in ni_vp amoung other things. 395 * 396 * XXXAUDIT: It would be desirable to also audit the name of the 397 * interpreter if this is an interpreted binary. 398 */ 399 if (args->fname != NULL) { 400 NDINIT(&nd, LOOKUP, ISOPEN | LOCKLEAF | FOLLOW | SAVENAME 401 | MPSAFE | AUDITVNODE1, UIO_SYSSPACE, args->fname, td); 402 } 403 404 SDT_PROBE(proc, kernel, , exec, args->fname, 0, 0, 0, 0 ); 405 406 interpret: 407 if (args->fname != NULL) { 408 error = namei(&nd); 409 if (error) 410 goto exec_fail; 411 412 vfslocked = NDHASGIANT(&nd); 413 binvp = nd.ni_vp; 414 imgp->vp = binvp; 415 } else { 416 AUDIT_ARG_FD(args->fd); 417 error = fgetvp(td, args->fd, &binvp); 418 if (error) 419 goto exec_fail; 420 vfslocked = VFS_LOCK_GIANT(binvp->v_mount); 421 vn_lock(binvp, LK_EXCLUSIVE | LK_RETRY); 422 AUDIT_ARG_VNODE(binvp, ARG_VNODE1); 423 imgp->vp = binvp; 424 } 425 426 /* 427 * Check file permissions (also 'opens' file) 428 */ 429 error = exec_check_permissions(imgp); 430 if (error) 431 goto exec_fail_dealloc; 432 433 imgp->object = imgp->vp->v_object; 434 if (imgp->object != NULL) 435 vm_object_reference(imgp->object); 436 437 /* 438 * Set VV_TEXT now so no one can write to the executable while we're 439 * activating it. 440 * 441 * Remember if this was set before and unset it in case this is not 442 * actually an executable image. 443 */ 444 textset = imgp->vp->v_vflag & VV_TEXT; 445 imgp->vp->v_vflag |= VV_TEXT; 446 447 error = exec_map_first_page(imgp); 448 if (error) 449 goto exec_fail_dealloc; 450 451 imgp->proc->p_osrel = 0; 452 /* 453 * If the current process has a special image activator it 454 * wants to try first, call it. For example, emulating shell 455 * scripts differently. 456 */ 457 error = -1; 458 if ((img_first = imgp->proc->p_sysent->sv_imgact_try) != NULL) 459 error = img_first(imgp); 460 461 /* 462 * Loop through the list of image activators, calling each one. 463 * An activator returns -1 if there is no match, 0 on success, 464 * and an error otherwise. 465 */ 466 for (i = 0; error == -1 && execsw[i]; ++i) { 467 if (execsw[i]->ex_imgact == NULL || 468 execsw[i]->ex_imgact == img_first) { 469 continue; 470 } 471 error = (*execsw[i]->ex_imgact)(imgp); 472 } 473 474 if (error) { 475 if (error == -1) { 476 if (textset == 0) 477 imgp->vp->v_vflag &= ~VV_TEXT; 478 error = ENOEXEC; 479 } 480 goto exec_fail_dealloc; 481 } 482 483 /* 484 * Special interpreter operation, cleanup and loop up to try to 485 * activate the interpreter. 486 */ 487 if (imgp->interpreted) { 488 exec_unmap_first_page(imgp); 489 /* 490 * VV_TEXT needs to be unset for scripts. There is a short 491 * period before we determine that something is a script where 492 * VV_TEXT will be set. The vnode lock is held over this 493 * entire period so nothing should illegitimately be blocked. 494 */ 495 imgp->vp->v_vflag &= ~VV_TEXT; 496 /* free name buffer and old vnode */ 497 if (args->fname != NULL) 498 NDFREE(&nd, NDF_ONLY_PNBUF); 499 #ifdef MAC 500 mac_execve_interpreter_enter(binvp, &interpvplabel); 501 #endif 502 if (imgp->opened) { 503 VOP_CLOSE(binvp, FREAD, td->td_ucred, td); 504 imgp->opened = 0; 505 } 506 vput(binvp); 507 vm_object_deallocate(imgp->object); 508 imgp->object = NULL; 509 VFS_UNLOCK_GIANT(vfslocked); 510 vfslocked = 0; 511 /* set new name to that of the interpreter */ 512 NDINIT(&nd, LOOKUP, LOCKLEAF | FOLLOW | SAVENAME | MPSAFE, 513 UIO_SYSSPACE, imgp->interpreter_name, td); 514 args->fname = imgp->interpreter_name; 515 goto interpret; 516 } 517 518 /* 519 * NB: We unlock the vnode here because it is believed that none 520 * of the sv_copyout_strings/sv_fixup operations require the vnode. 521 */ 522 VOP_UNLOCK(imgp->vp, 0); 523 524 /* 525 * Do the best to calculate the full path to the image file. 526 */ 527 if (imgp->auxargs != NULL && 528 ((args->fname != NULL && args->fname[0] == '/') || 529 vn_fullpath(td, imgp->vp, &imgp->execpath, &imgp->freepath) != 0)) 530 imgp->execpath = args->fname; 531 532 /* 533 * Copy out strings (args and env) and initialize stack base 534 */ 535 if (p->p_sysent->sv_copyout_strings) 536 stack_base = (*p->p_sysent->sv_copyout_strings)(imgp); 537 else 538 stack_base = exec_copyout_strings(imgp); 539 540 /* 541 * If custom stack fixup routine present for this process 542 * let it do the stack setup. 543 * Else stuff argument count as first item on stack 544 */ 545 if (p->p_sysent->sv_fixup != NULL) 546 (*p->p_sysent->sv_fixup)(&stack_base, imgp); 547 else 548 suword(--stack_base, imgp->args->argc); 549 550 /* 551 * For security and other reasons, the file descriptor table cannot 552 * be shared after an exec. 553 */ 554 fdunshare(p, td); 555 556 /* 557 * Malloc things before we need locks. 558 */ 559 newcred = crget(); 560 euip = uifind(attr.va_uid); 561 i = imgp->args->begin_envv - imgp->args->begin_argv; 562 /* Cache arguments if they fit inside our allowance */ 563 if (ps_arg_cache_limit >= i + sizeof(struct pargs)) { 564 newargs = pargs_alloc(i); 565 bcopy(imgp->args->begin_argv, newargs->ar_args, i); 566 } 567 568 /* close files on exec */ 569 fdcloseexec(td); 570 vn_lock(imgp->vp, LK_EXCLUSIVE | LK_RETRY); 571 572 /* Get a reference to the vnode prior to locking the proc */ 573 VREF(binvp); 574 575 /* 576 * For security and other reasons, signal handlers cannot 577 * be shared after an exec. The new process gets a copy of the old 578 * handlers. In execsigs(), the new process will have its signals 579 * reset. 580 */ 581 PROC_LOCK(p); 582 oldcred = crcopysafe(p, newcred); 583 if (sigacts_shared(p->p_sigacts)) { 584 oldsigacts = p->p_sigacts; 585 PROC_UNLOCK(p); 586 newsigacts = sigacts_alloc(); 587 sigacts_copy(newsigacts, oldsigacts); 588 PROC_LOCK(p); 589 p->p_sigacts = newsigacts; 590 } else 591 oldsigacts = NULL; 592 593 /* Stop profiling */ 594 stopprofclock(p); 595 596 /* reset caught signals */ 597 execsigs(p); 598 599 /* name this process - nameiexec(p, ndp) */ 600 if (args->fname) { 601 len = min(nd.ni_cnd.cn_namelen,MAXCOMLEN); 602 bcopy(nd.ni_cnd.cn_nameptr, p->p_comm, len); 603 } else { 604 if (vn_commname(binvp, p->p_comm, MAXCOMLEN + 1) == 0) 605 len = MAXCOMLEN; 606 else { 607 len = sizeof(fexecv_proc_title); 608 bcopy(fexecv_proc_title, p->p_comm, len); 609 } 610 } 611 p->p_comm[len] = 0; 612 bcopy(p->p_comm, td->td_name, sizeof(td->td_name)); 613 614 /* 615 * mark as execed, wakeup the process that vforked (if any) and tell 616 * it that it now has its own resources back 617 */ 618 p->p_flag |= P_EXEC; 619 if (p->p_pptr && (p->p_flag & P_PPWAIT)) { 620 p->p_flag &= ~P_PPWAIT; 621 cv_broadcast(&p->p_pwait); 622 } 623 624 /* 625 * Implement image setuid/setgid. 626 * 627 * Don't honor setuid/setgid if the filesystem prohibits it or if 628 * the process is being traced. 629 * 630 * XXXMAC: For the time being, use NOSUID to also prohibit 631 * transitions on the file system. 632 */ 633 credential_changing = 0; 634 credential_changing |= (attr.va_mode & S_ISUID) && oldcred->cr_uid != 635 attr.va_uid; 636 credential_changing |= (attr.va_mode & S_ISGID) && oldcred->cr_gid != 637 attr.va_gid; 638 #ifdef MAC 639 will_transition = mac_vnode_execve_will_transition(oldcred, imgp->vp, 640 interpvplabel, imgp); 641 credential_changing |= will_transition; 642 #endif 643 644 if (credential_changing && 645 (imgp->vp->v_mount->mnt_flag & MNT_NOSUID) == 0 && 646 (p->p_flag & P_TRACED) == 0) { 647 /* 648 * Turn off syscall tracing for set-id programs, except for 649 * root. Record any set-id flags first to make sure that 650 * we do not regain any tracing during a possible block. 651 */ 652 setsugid(p); 653 654 #ifdef KTRACE 655 if (p->p_tracevp != NULL && 656 priv_check_cred(oldcred, PRIV_DEBUG_DIFFCRED, 0)) { 657 mtx_lock(&ktrace_mtx); 658 p->p_traceflag = 0; 659 tracevp = p->p_tracevp; 660 p->p_tracevp = NULL; 661 tracecred = p->p_tracecred; 662 p->p_tracecred = NULL; 663 mtx_unlock(&ktrace_mtx); 664 } 665 #endif 666 /* 667 * Close any file descriptors 0..2 that reference procfs, 668 * then make sure file descriptors 0..2 are in use. 669 * 670 * setugidsafety() may call closef() and then pfind() 671 * which may grab the process lock. 672 * fdcheckstd() may call falloc() which may block to 673 * allocate memory, so temporarily drop the process lock. 674 */ 675 PROC_UNLOCK(p); 676 setugidsafety(td); 677 VOP_UNLOCK(imgp->vp, 0); 678 error = fdcheckstd(td); 679 vn_lock(imgp->vp, LK_EXCLUSIVE | LK_RETRY); 680 if (error != 0) 681 goto done1; 682 PROC_LOCK(p); 683 /* 684 * Set the new credentials. 685 */ 686 if (attr.va_mode & S_ISUID) 687 change_euid(newcred, euip); 688 if (attr.va_mode & S_ISGID) 689 change_egid(newcred, attr.va_gid); 690 #ifdef MAC 691 if (will_transition) { 692 mac_vnode_execve_transition(oldcred, newcred, imgp->vp, 693 interpvplabel, imgp); 694 } 695 #endif 696 /* 697 * Implement correct POSIX saved-id behavior. 698 * 699 * XXXMAC: Note that the current logic will save the 700 * uid and gid if a MAC domain transition occurs, even 701 * though maybe it shouldn't. 702 */ 703 change_svuid(newcred, newcred->cr_uid); 704 change_svgid(newcred, newcred->cr_gid); 705 p->p_ucred = newcred; 706 newcred = NULL; 707 } else { 708 if (oldcred->cr_uid == oldcred->cr_ruid && 709 oldcred->cr_gid == oldcred->cr_rgid) 710 p->p_flag &= ~P_SUGID; 711 /* 712 * Implement correct POSIX saved-id behavior. 713 * 714 * XXX: It's not clear that the existing behavior is 715 * POSIX-compliant. A number of sources indicate that the 716 * saved uid/gid should only be updated if the new ruid is 717 * not equal to the old ruid, or the new euid is not equal 718 * to the old euid and the new euid is not equal to the old 719 * ruid. The FreeBSD code always updates the saved uid/gid. 720 * Also, this code uses the new (replaced) euid and egid as 721 * the source, which may or may not be the right ones to use. 722 */ 723 if (oldcred->cr_svuid != oldcred->cr_uid || 724 oldcred->cr_svgid != oldcred->cr_gid) { 725 change_svuid(newcred, newcred->cr_uid); 726 change_svgid(newcred, newcred->cr_gid); 727 p->p_ucred = newcred; 728 newcred = NULL; 729 } 730 } 731 732 /* 733 * Store the vp for use in procfs. This vnode was referenced prior 734 * to locking the proc lock. 735 */ 736 textvp = p->p_textvp; 737 p->p_textvp = binvp; 738 739 #ifdef KDTRACE_HOOKS 740 /* 741 * Tell the DTrace fasttrap provider about the exec if it 742 * has declared an interest. 743 */ 744 if (dtrace_fasttrap_exec) 745 dtrace_fasttrap_exec(p); 746 #endif 747 748 /* 749 * Notify others that we exec'd, and clear the P_INEXEC flag 750 * as we're now a bona fide freshly-execed process. 751 */ 752 KNOTE_LOCKED(&p->p_klist, NOTE_EXEC); 753 p->p_flag &= ~P_INEXEC; 754 755 /* 756 * If tracing the process, trap to debugger so breakpoints 757 * can be set before the program executes. 758 * Use tdsignal to deliver signal to current thread, use 759 * psignal may cause the signal to be delivered to wrong thread 760 * because that thread will exit, remember we are going to enter 761 * single thread mode. 762 */ 763 if (p->p_flag & P_TRACED) 764 tdsignal(p, td, SIGTRAP, NULL); 765 766 /* clear "fork but no exec" flag, as we _are_ execing */ 767 p->p_acflag &= ~AFORK; 768 769 /* 770 * Free any previous argument cache and replace it with 771 * the new argument cache, if any. 772 */ 773 oldargs = p->p_args; 774 p->p_args = newargs; 775 newargs = NULL; 776 777 #ifdef HWPMC_HOOKS 778 /* 779 * Check if system-wide sampling is in effect or if the 780 * current process is using PMCs. If so, do exec() time 781 * processing. This processing needs to happen AFTER the 782 * P_INEXEC flag is cleared. 783 * 784 * The proc lock needs to be released before taking the PMC 785 * SX. 786 */ 787 if (PMC_SYSTEM_SAMPLING_ACTIVE() || PMC_PROC_IS_USING_PMCS(p)) { 788 PROC_UNLOCK(p); 789 pe.pm_credentialschanged = credential_changing; 790 pe.pm_entryaddr = imgp->entry_addr; 791 792 PMC_CALL_HOOK_X(td, PMC_FN_PROCESS_EXEC, (void *) &pe); 793 } else 794 PROC_UNLOCK(p); 795 #else /* !HWPMC_HOOKS */ 796 PROC_UNLOCK(p); 797 #endif 798 799 /* Set values passed into the program in registers. */ 800 if (p->p_sysent->sv_setregs) 801 (*p->p_sysent->sv_setregs)(td, imgp->entry_addr, 802 (u_long)(uintptr_t)stack_base, imgp->ps_strings); 803 else 804 exec_setregs(td, imgp->entry_addr, 805 (u_long)(uintptr_t)stack_base, imgp->ps_strings); 806 807 vfs_mark_atime(imgp->vp, td->td_ucred); 808 809 SDT_PROBE(proc, kernel, , exec_success, args->fname, 0, 0, 0, 0); 810 811 done1: 812 /* 813 * Free any resources malloc'd earlier that we didn't use. 814 */ 815 uifree(euip); 816 if (newcred == NULL) 817 crfree(oldcred); 818 else 819 crfree(newcred); 820 VOP_UNLOCK(imgp->vp, 0); 821 822 /* 823 * Handle deferred decrement of ref counts. 824 */ 825 if (textvp != NULL) { 826 int tvfslocked; 827 828 tvfslocked = VFS_LOCK_GIANT(textvp->v_mount); 829 vrele(textvp); 830 VFS_UNLOCK_GIANT(tvfslocked); 831 } 832 if (binvp && error != 0) 833 vrele(binvp); 834 #ifdef KTRACE 835 if (tracevp != NULL) { 836 int tvfslocked; 837 838 tvfslocked = VFS_LOCK_GIANT(tracevp->v_mount); 839 vrele(tracevp); 840 VFS_UNLOCK_GIANT(tvfslocked); 841 } 842 if (tracecred != NULL) 843 crfree(tracecred); 844 #endif 845 vn_lock(imgp->vp, LK_EXCLUSIVE | LK_RETRY); 846 pargs_drop(oldargs); 847 pargs_drop(newargs); 848 if (oldsigacts != NULL) 849 sigacts_free(oldsigacts); 850 851 exec_fail_dealloc: 852 853 /* 854 * free various allocated resources 855 */ 856 if (imgp->firstpage != NULL) 857 exec_unmap_first_page(imgp); 858 859 if (imgp->vp != NULL) { 860 if (args->fname) 861 NDFREE(&nd, NDF_ONLY_PNBUF); 862 if (imgp->opened) 863 VOP_CLOSE(imgp->vp, FREAD, td->td_ucred, td); 864 vput(imgp->vp); 865 } 866 867 if (imgp->object != NULL) 868 vm_object_deallocate(imgp->object); 869 870 free(imgp->freepath, M_TEMP); 871 872 if (error == 0) { 873 /* 874 * Stop the process here if its stop event mask has 875 * the S_EXEC bit set. 876 */ 877 STOPEVENT(p, S_EXEC, 0); 878 goto done2; 879 } 880 881 exec_fail: 882 /* we're done here, clear P_INEXEC */ 883 PROC_LOCK(p); 884 p->p_flag &= ~P_INEXEC; 885 PROC_UNLOCK(p); 886 887 SDT_PROBE(proc, kernel, , exec_failure, error, 0, 0, 0, 0); 888 889 done2: 890 #ifdef MAC 891 mac_execve_exit(imgp); 892 mac_execve_interpreter_exit(interpvplabel); 893 #endif 894 VFS_UNLOCK_GIANT(vfslocked); 895 exec_free_args(args); 896 897 if (error && imgp->vmspace_destroyed) { 898 /* sorry, no more process anymore. exit gracefully */ 899 exit1(td, W_EXITCODE(0, SIGABRT)); 900 /* NOT REACHED */ 901 } 902 return (error); 903 } 904 905 int 906 exec_map_first_page(imgp) 907 struct image_params *imgp; 908 { 909 int rv, i; 910 int initial_pagein; 911 vm_page_t ma[VM_INITIAL_PAGEIN]; 912 vm_object_t object; 913 914 if (imgp->firstpage != NULL) 915 exec_unmap_first_page(imgp); 916 917 object = imgp->vp->v_object; 918 if (object == NULL) 919 return (EACCES); 920 VM_OBJECT_LOCK(object); 921 #if VM_NRESERVLEVEL > 0 922 if ((object->flags & OBJ_COLORED) == 0) { 923 object->flags |= OBJ_COLORED; 924 object->pg_color = 0; 925 } 926 #endif 927 ma[0] = vm_page_grab(object, 0, VM_ALLOC_NORMAL | VM_ALLOC_RETRY); 928 if (ma[0]->valid != VM_PAGE_BITS_ALL) { 929 initial_pagein = VM_INITIAL_PAGEIN; 930 if (initial_pagein > object->size) 931 initial_pagein = object->size; 932 for (i = 1; i < initial_pagein; i++) { 933 if ((ma[i] = vm_page_lookup(object, i)) != NULL) { 934 if (ma[i]->valid) 935 break; 936 if ((ma[i]->oflags & VPO_BUSY) || ma[i]->busy) 937 break; 938 vm_page_busy(ma[i]); 939 } else { 940 ma[i] = vm_page_alloc(object, i, 941 VM_ALLOC_NORMAL | VM_ALLOC_IFNOTCACHED); 942 if (ma[i] == NULL) 943 break; 944 } 945 } 946 initial_pagein = i; 947 rv = vm_pager_get_pages(object, ma, initial_pagein, 0); 948 ma[0] = vm_page_lookup(object, 0); 949 if ((rv != VM_PAGER_OK) || (ma[0] == NULL)) { 950 if (ma[0]) { 951 vm_page_lock_queues(); 952 vm_page_free(ma[0]); 953 vm_page_unlock_queues(); 954 } 955 VM_OBJECT_UNLOCK(object); 956 return (EIO); 957 } 958 } 959 vm_page_lock_queues(); 960 vm_page_hold(ma[0]); 961 vm_page_unlock_queues(); 962 vm_page_wakeup(ma[0]); 963 VM_OBJECT_UNLOCK(object); 964 965 imgp->firstpage = sf_buf_alloc(ma[0], 0); 966 imgp->image_header = (char *)sf_buf_kva(imgp->firstpage); 967 968 return (0); 969 } 970 971 void 972 exec_unmap_first_page(imgp) 973 struct image_params *imgp; 974 { 975 vm_page_t m; 976 977 if (imgp->firstpage != NULL) { 978 m = sf_buf_page(imgp->firstpage); 979 sf_buf_free(imgp->firstpage); 980 imgp->firstpage = NULL; 981 vm_page_lock_queues(); 982 vm_page_unhold(m); 983 vm_page_unlock_queues(); 984 } 985 } 986 987 /* 988 * Destroy old address space, and allocate a new stack 989 * The new stack is only SGROWSIZ large because it is grown 990 * automatically in trap.c. 991 */ 992 int 993 exec_new_vmspace(imgp, sv) 994 struct image_params *imgp; 995 struct sysentvec *sv; 996 { 997 int error; 998 struct proc *p = imgp->proc; 999 struct vmspace *vmspace = p->p_vmspace; 1000 vm_offset_t stack_addr; 1001 vm_map_t map; 1002 u_long ssiz; 1003 1004 imgp->vmspace_destroyed = 1; 1005 imgp->sysent = sv; 1006 1007 /* May be called with Giant held */ 1008 EVENTHANDLER_INVOKE(process_exec, p, imgp); 1009 1010 /* 1011 * Blow away entire process VM, if address space not shared, 1012 * otherwise, create a new VM space so that other threads are 1013 * not disrupted 1014 */ 1015 map = &vmspace->vm_map; 1016 if (vmspace->vm_refcnt == 1 && vm_map_min(map) == sv->sv_minuser && 1017 vm_map_max(map) == sv->sv_maxuser) { 1018 shmexit(vmspace); 1019 pmap_remove_pages(vmspace_pmap(vmspace)); 1020 vm_map_remove(map, vm_map_min(map), vm_map_max(map)); 1021 } else { 1022 error = vmspace_exec(p, sv->sv_minuser, sv->sv_maxuser); 1023 if (error) 1024 return (error); 1025 vmspace = p->p_vmspace; 1026 map = &vmspace->vm_map; 1027 } 1028 1029 /* Allocate a new stack */ 1030 if (sv->sv_maxssiz != NULL) 1031 ssiz = *sv->sv_maxssiz; 1032 else 1033 ssiz = maxssiz; 1034 stack_addr = sv->sv_usrstack - ssiz; 1035 error = vm_map_stack(map, stack_addr, (vm_size_t)ssiz, 1036 sv->sv_stackprot, VM_PROT_ALL, MAP_STACK_GROWS_DOWN); 1037 if (error) 1038 return (error); 1039 1040 #ifdef __ia64__ 1041 /* Allocate a new register stack */ 1042 stack_addr = IA64_BACKINGSTORE; 1043 error = vm_map_stack(map, stack_addr, (vm_size_t)ssiz, 1044 sv->sv_stackprot, VM_PROT_ALL, MAP_STACK_GROWS_UP); 1045 if (error) 1046 return (error); 1047 #endif 1048 1049 /* vm_ssize and vm_maxsaddr are somewhat antiquated concepts in the 1050 * VM_STACK case, but they are still used to monitor the size of the 1051 * process stack so we can check the stack rlimit. 1052 */ 1053 vmspace->vm_ssize = sgrowsiz >> PAGE_SHIFT; 1054 vmspace->vm_maxsaddr = (char *)sv->sv_usrstack - ssiz; 1055 1056 return (0); 1057 } 1058 1059 /* 1060 * Copy out argument and environment strings from the old process address 1061 * space into the temporary string buffer. 1062 */ 1063 int 1064 exec_copyin_args(struct image_args *args, char *fname, 1065 enum uio_seg segflg, char **argv, char **envv) 1066 { 1067 char *argp, *envp; 1068 int error; 1069 size_t length; 1070 1071 bzero(args, sizeof(*args)); 1072 if (argv == NULL) 1073 return (EFAULT); 1074 /* 1075 * Allocate temporary demand zeroed space for argument and 1076 * environment strings: 1077 * 1078 * o ARG_MAX for argument and environment; 1079 * o MAXSHELLCMDLEN for the name of interpreters. 1080 */ 1081 args->buf = (char *) kmem_alloc_wait(exec_map, 1082 PATH_MAX + ARG_MAX + MAXSHELLCMDLEN); 1083 if (args->buf == NULL) 1084 return (ENOMEM); 1085 args->begin_argv = args->buf; 1086 args->endp = args->begin_argv; 1087 args->stringspace = ARG_MAX; 1088 /* 1089 * Copy the file name. 1090 */ 1091 if (fname != NULL) { 1092 args->fname = args->buf + ARG_MAX; 1093 error = (segflg == UIO_SYSSPACE) ? 1094 copystr(fname, args->fname, PATH_MAX, &length) : 1095 copyinstr(fname, args->fname, PATH_MAX, &length); 1096 if (error != 0) 1097 goto err_exit; 1098 } else 1099 args->fname = NULL; 1100 1101 /* 1102 * extract arguments first 1103 */ 1104 while ((argp = (caddr_t) (intptr_t) fuword(argv++))) { 1105 if (argp == (caddr_t) -1) { 1106 error = EFAULT; 1107 goto err_exit; 1108 } 1109 if ((error = copyinstr(argp, args->endp, 1110 args->stringspace, &length))) { 1111 if (error == ENAMETOOLONG) 1112 error = E2BIG; 1113 goto err_exit; 1114 } 1115 args->stringspace -= length; 1116 args->endp += length; 1117 args->argc++; 1118 } 1119 1120 args->begin_envv = args->endp; 1121 1122 /* 1123 * extract environment strings 1124 */ 1125 if (envv) { 1126 while ((envp = (caddr_t)(intptr_t)fuword(envv++))) { 1127 if (envp == (caddr_t)-1) { 1128 error = EFAULT; 1129 goto err_exit; 1130 } 1131 if ((error = copyinstr(envp, args->endp, 1132 args->stringspace, &length))) { 1133 if (error == ENAMETOOLONG) 1134 error = E2BIG; 1135 goto err_exit; 1136 } 1137 args->stringspace -= length; 1138 args->endp += length; 1139 args->envc++; 1140 } 1141 } 1142 1143 return (0); 1144 1145 err_exit: 1146 exec_free_args(args); 1147 return (error); 1148 } 1149 1150 static void 1151 exec_free_args(struct image_args *args) 1152 { 1153 1154 if (args->buf) { 1155 kmem_free_wakeup(exec_map, (vm_offset_t)args->buf, 1156 PATH_MAX + ARG_MAX + MAXSHELLCMDLEN); 1157 args->buf = NULL; 1158 } 1159 } 1160 1161 /* 1162 * Copy strings out to the new process address space, constructing new arg 1163 * and env vector tables. Return a pointer to the base so that it can be used 1164 * as the initial stack pointer. 1165 */ 1166 register_t * 1167 exec_copyout_strings(imgp) 1168 struct image_params *imgp; 1169 { 1170 int argc, envc; 1171 char **vectp; 1172 char *stringp, *destp; 1173 register_t *stack_base; 1174 struct ps_strings *arginfo; 1175 struct proc *p; 1176 size_t execpath_len; 1177 int szsigcode; 1178 1179 /* 1180 * Calculate string base and vector table pointers. 1181 * Also deal with signal trampoline code for this exec type. 1182 */ 1183 if (imgp->execpath != NULL && imgp->auxargs != NULL) 1184 execpath_len = strlen(imgp->execpath) + 1; 1185 else 1186 execpath_len = 0; 1187 p = imgp->proc; 1188 szsigcode = 0; 1189 arginfo = (struct ps_strings *)p->p_sysent->sv_psstrings; 1190 if (p->p_sysent->sv_szsigcode != NULL) 1191 szsigcode = *(p->p_sysent->sv_szsigcode); 1192 destp = (caddr_t)arginfo - szsigcode - SPARE_USRSPACE - 1193 roundup(execpath_len, sizeof(char *)) - 1194 roundup((ARG_MAX - imgp->args->stringspace), sizeof(char *)); 1195 1196 /* 1197 * install sigcode 1198 */ 1199 if (szsigcode) 1200 copyout(p->p_sysent->sv_sigcode, ((caddr_t)arginfo - 1201 szsigcode), szsigcode); 1202 1203 /* 1204 * Copy the image path for the rtld. 1205 */ 1206 if (execpath_len != 0) { 1207 imgp->execpathp = (uintptr_t)arginfo - szsigcode - execpath_len; 1208 copyout(imgp->execpath, (void *)imgp->execpathp, 1209 execpath_len); 1210 } 1211 1212 /* 1213 * If we have a valid auxargs ptr, prepare some room 1214 * on the stack. 1215 */ 1216 if (imgp->auxargs) { 1217 /* 1218 * 'AT_COUNT*2' is size for the ELF Auxargs data. This is for 1219 * lower compatibility. 1220 */ 1221 imgp->auxarg_size = (imgp->auxarg_size) ? imgp->auxarg_size : 1222 (AT_COUNT * 2); 1223 /* 1224 * The '+ 2' is for the null pointers at the end of each of 1225 * the arg and env vector sets,and imgp->auxarg_size is room 1226 * for argument of Runtime loader. 1227 */ 1228 vectp = (char **)(destp - (imgp->args->argc + 1229 imgp->args->envc + 2 + imgp->auxarg_size + execpath_len) * 1230 sizeof(char *)); 1231 } else { 1232 /* 1233 * The '+ 2' is for the null pointers at the end of each of 1234 * the arg and env vector sets 1235 */ 1236 vectp = (char **)(destp - (imgp->args->argc + imgp->args->envc + 2) * 1237 sizeof(char *)); 1238 } 1239 1240 /* 1241 * vectp also becomes our initial stack base 1242 */ 1243 stack_base = (register_t *)vectp; 1244 1245 stringp = imgp->args->begin_argv; 1246 argc = imgp->args->argc; 1247 envc = imgp->args->envc; 1248 1249 /* 1250 * Copy out strings - arguments and environment. 1251 */ 1252 copyout(stringp, destp, ARG_MAX - imgp->args->stringspace); 1253 1254 /* 1255 * Fill in "ps_strings" struct for ps, w, etc. 1256 */ 1257 suword(&arginfo->ps_argvstr, (long)(intptr_t)vectp); 1258 suword(&arginfo->ps_nargvstr, argc); 1259 1260 /* 1261 * Fill in argument portion of vector table. 1262 */ 1263 for (; argc > 0; --argc) { 1264 suword(vectp++, (long)(intptr_t)destp); 1265 while (*stringp++ != 0) 1266 destp++; 1267 destp++; 1268 } 1269 1270 /* a null vector table pointer separates the argp's from the envp's */ 1271 suword(vectp++, 0); 1272 1273 suword(&arginfo->ps_envstr, (long)(intptr_t)vectp); 1274 suword(&arginfo->ps_nenvstr, envc); 1275 1276 /* 1277 * Fill in environment portion of vector table. 1278 */ 1279 for (; envc > 0; --envc) { 1280 suword(vectp++, (long)(intptr_t)destp); 1281 while (*stringp++ != 0) 1282 destp++; 1283 destp++; 1284 } 1285 1286 /* end of vector table is a null pointer */ 1287 suword(vectp, 0); 1288 1289 return (stack_base); 1290 } 1291 1292 /* 1293 * Check permissions of file to execute. 1294 * Called with imgp->vp locked. 1295 * Return 0 for success or error code on failure. 1296 */ 1297 int 1298 exec_check_permissions(imgp) 1299 struct image_params *imgp; 1300 { 1301 struct vnode *vp = imgp->vp; 1302 struct vattr *attr = imgp->attr; 1303 struct thread *td; 1304 int error; 1305 1306 td = curthread; 1307 1308 /* Get file attributes */ 1309 error = VOP_GETATTR(vp, attr, td->td_ucred); 1310 if (error) 1311 return (error); 1312 1313 #ifdef MAC 1314 error = mac_vnode_check_exec(td->td_ucred, imgp->vp, imgp); 1315 if (error) 1316 return (error); 1317 #endif 1318 1319 /* 1320 * 1) Check if file execution is disabled for the filesystem that this 1321 * file resides on. 1322 * 2) Insure that at least one execute bit is on - otherwise root 1323 * will always succeed, and we don't want to happen unless the 1324 * file really is executable. 1325 * 3) Insure that the file is a regular file. 1326 */ 1327 if ((vp->v_mount->mnt_flag & MNT_NOEXEC) || 1328 ((attr->va_mode & 0111) == 0) || 1329 (attr->va_type != VREG)) 1330 return (EACCES); 1331 1332 /* 1333 * Zero length files can't be exec'd 1334 */ 1335 if (attr->va_size == 0) 1336 return (ENOEXEC); 1337 1338 /* 1339 * Check for execute permission to file based on current credentials. 1340 */ 1341 error = VOP_ACCESS(vp, VEXEC, td->td_ucred, td); 1342 if (error) 1343 return (error); 1344 1345 /* 1346 * Check number of open-for-writes on the file and deny execution 1347 * if there are any. 1348 */ 1349 if (vp->v_writecount) 1350 return (ETXTBSY); 1351 1352 /* 1353 * Call filesystem specific open routine (which does nothing in the 1354 * general case). 1355 */ 1356 error = VOP_OPEN(vp, FREAD, td->td_ucred, td, NULL); 1357 if (error == 0) 1358 imgp->opened = 1; 1359 return (error); 1360 } 1361 1362 /* 1363 * Exec handler registration 1364 */ 1365 int 1366 exec_register(execsw_arg) 1367 const struct execsw *execsw_arg; 1368 { 1369 const struct execsw **es, **xs, **newexecsw; 1370 int count = 2; /* New slot and trailing NULL */ 1371 1372 if (execsw) 1373 for (es = execsw; *es; es++) 1374 count++; 1375 newexecsw = malloc(count * sizeof(*es), M_TEMP, M_WAITOK); 1376 if (newexecsw == NULL) 1377 return (ENOMEM); 1378 xs = newexecsw; 1379 if (execsw) 1380 for (es = execsw; *es; es++) 1381 *xs++ = *es; 1382 *xs++ = execsw_arg; 1383 *xs = NULL; 1384 if (execsw) 1385 free(execsw, M_TEMP); 1386 execsw = newexecsw; 1387 return (0); 1388 } 1389 1390 int 1391 exec_unregister(execsw_arg) 1392 const struct execsw *execsw_arg; 1393 { 1394 const struct execsw **es, **xs, **newexecsw; 1395 int count = 1; 1396 1397 if (execsw == NULL) 1398 panic("unregister with no handlers left?\n"); 1399 1400 for (es = execsw; *es; es++) { 1401 if (*es == execsw_arg) 1402 break; 1403 } 1404 if (*es == NULL) 1405 return (ENOENT); 1406 for (es = execsw; *es; es++) 1407 if (*es != execsw_arg) 1408 count++; 1409 newexecsw = malloc(count * sizeof(*es), M_TEMP, M_WAITOK); 1410 if (newexecsw == NULL) 1411 return (ENOMEM); 1412 xs = newexecsw; 1413 for (es = execsw; *es; es++) 1414 if (*es != execsw_arg) 1415 *xs++ = *es; 1416 *xs = NULL; 1417 if (execsw) 1418 free(execsw, M_TEMP); 1419 execsw = newexecsw; 1420 return (0); 1421 } 1422