Now available: The Design and Implementation of the FreeBSD Operating System (Second Edition)
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FreeBSD/Linux Kernel Cross Reference
sys/kern/kern_exec.c
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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: releng/10.4/sys/kern/kern_exec.c 321359 2017-07-22 04:57:51Z alc $"); 29 30 #include "opt_capsicum.h" 31 #include "opt_hwpmc_hooks.h" 32 #include "opt_kdtrace.h" 33 #include "opt_ktrace.h" 34 #include "opt_vm.h" 35 36 #include <sys/param.h> 37 #include <sys/capsicum.h> 38 #include <sys/systm.h> 39 #include <sys/capsicum.h> 40 #include <sys/eventhandler.h> 41 #include <sys/lock.h> 42 #include <sys/mutex.h> 43 #include <sys/sysproto.h> 44 #include <sys/signalvar.h> 45 #include <sys/kernel.h> 46 #include <sys/mount.h> 47 #include <sys/filedesc.h> 48 #include <sys/fcntl.h> 49 #include <sys/acct.h> 50 #include <sys/exec.h> 51 #include <sys/imgact.h> 52 #include <sys/imgact_elf.h> 53 #include <sys/wait.h> 54 #include <sys/malloc.h> 55 #include <sys/priv.h> 56 #include <sys/proc.h> 57 #include <sys/pioctl.h> 58 #include <sys/ptrace.h> 59 #include <sys/namei.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/syscallsubr.h> 66 #include <sys/sysent.h> 67 #include <sys/shm.h> 68 #include <sys/sysctl.h> 69 #include <sys/vnode.h> 70 #include <sys/stat.h> 71 #ifdef KTRACE 72 #include <sys/ktrace.h> 73 #endif 74 75 #include <vm/vm.h> 76 #include <vm/vm_param.h> 77 #include <vm/pmap.h> 78 #include <vm/vm_page.h> 79 #include <vm/vm_map.h> 80 #include <vm/vm_kern.h> 81 #include <vm/vm_extern.h> 82 #include <vm/vm_object.h> 83 #include <vm/vm_pager.h> 84 85 #ifdef HWPMC_HOOKS 86 #include <sys/pmckern.h> 87 #endif 88 89 #include <machine/reg.h> 90 91 #include <security/audit/audit.h> 92 #include <security/mac/mac_framework.h> 93 94 #ifdef KDTRACE_HOOKS 95 #include <sys/dtrace_bsd.h> 96 dtrace_execexit_func_t dtrace_fasttrap_exec; 97 #endif 98 99 SDT_PROVIDER_DECLARE(proc); 100 SDT_PROBE_DEFINE1(proc, , , exec, "char *"); 101 SDT_PROBE_DEFINE1(proc, , , exec__failure, "int"); 102 SDT_PROBE_DEFINE1(proc, , , exec__success, "char *"); 103 104 MALLOC_DEFINE(M_PARGS, "proc-args", "Process arguments"); 105 106 int coredump_pack_fileinfo = 1; 107 SYSCTL_INT(_kern, OID_AUTO, coredump_pack_fileinfo, CTLFLAG_RWTUN, 108 &coredump_pack_fileinfo, 0, 109 "Enable file path packing in 'procstat -f' coredump notes"); 110 111 int coredump_pack_vmmapinfo = 1; 112 SYSCTL_INT(_kern, OID_AUTO, coredump_pack_vmmapinfo, CTLFLAG_RWTUN, 113 &coredump_pack_vmmapinfo, 0, 114 "Enable file path packing in 'procstat -v' coredump notes"); 115 116 static int sysctl_kern_ps_strings(SYSCTL_HANDLER_ARGS); 117 static int sysctl_kern_usrstack(SYSCTL_HANDLER_ARGS); 118 static int sysctl_kern_stackprot(SYSCTL_HANDLER_ARGS); 119 static int do_execve(struct thread *td, struct image_args *args, 120 struct mac *mac_p); 121 122 /* XXX This should be vm_size_t. */ 123 SYSCTL_PROC(_kern, KERN_PS_STRINGS, ps_strings, CTLTYPE_ULONG|CTLFLAG_RD, 124 NULL, 0, sysctl_kern_ps_strings, "LU", ""); 125 126 /* XXX This should be vm_size_t. */ 127 SYSCTL_PROC(_kern, KERN_USRSTACK, usrstack, CTLTYPE_ULONG|CTLFLAG_RD| 128 CTLFLAG_CAPRD, NULL, 0, sysctl_kern_usrstack, "LU", ""); 129 130 SYSCTL_PROC(_kern, OID_AUTO, stackprot, CTLTYPE_INT|CTLFLAG_RD, 131 NULL, 0, sysctl_kern_stackprot, "I", ""); 132 133 u_long ps_arg_cache_limit = PAGE_SIZE / 16; 134 SYSCTL_ULONG(_kern, OID_AUTO, ps_arg_cache_limit, CTLFLAG_RW, 135 &ps_arg_cache_limit, 0, ""); 136 137 static int disallow_high_osrel; 138 SYSCTL_INT(_kern, OID_AUTO, disallow_high_osrel, CTLFLAG_RW, 139 &disallow_high_osrel, 0, 140 "Disallow execution of binaries built for higher version of the world"); 141 142 static int map_at_zero = 0; 143 TUNABLE_INT("security.bsd.map_at_zero", &map_at_zero); 144 SYSCTL_INT(_security_bsd, OID_AUTO, map_at_zero, CTLFLAG_RW, &map_at_zero, 0, 145 "Permit processes to map an object at virtual address 0."); 146 147 static int 148 sysctl_kern_ps_strings(SYSCTL_HANDLER_ARGS) 149 { 150 struct proc *p; 151 int error; 152 153 p = curproc; 154 #ifdef SCTL_MASK32 155 if (req->flags & SCTL_MASK32) { 156 unsigned int val; 157 val = (unsigned int)p->p_sysent->sv_psstrings; 158 error = SYSCTL_OUT(req, &val, sizeof(val)); 159 } else 160 #endif 161 error = SYSCTL_OUT(req, &p->p_sysent->sv_psstrings, 162 sizeof(p->p_sysent->sv_psstrings)); 163 return error; 164 } 165 166 static int 167 sysctl_kern_usrstack(SYSCTL_HANDLER_ARGS) 168 { 169 struct proc *p; 170 int error; 171 172 p = curproc; 173 #ifdef SCTL_MASK32 174 if (req->flags & SCTL_MASK32) { 175 unsigned int val; 176 val = (unsigned int)p->p_sysent->sv_usrstack; 177 error = SYSCTL_OUT(req, &val, sizeof(val)); 178 } else 179 #endif 180 error = SYSCTL_OUT(req, &p->p_sysent->sv_usrstack, 181 sizeof(p->p_sysent->sv_usrstack)); 182 return error; 183 } 184 185 static int 186 sysctl_kern_stackprot(SYSCTL_HANDLER_ARGS) 187 { 188 struct proc *p; 189 190 p = curproc; 191 return (SYSCTL_OUT(req, &p->p_sysent->sv_stackprot, 192 sizeof(p->p_sysent->sv_stackprot))); 193 } 194 195 /* 196 * Each of the items is a pointer to a `const struct execsw', hence the 197 * double pointer here. 198 */ 199 static const struct execsw **execsw; 200 201 #ifndef _SYS_SYSPROTO_H_ 202 struct execve_args { 203 char *fname; 204 char **argv; 205 char **envv; 206 }; 207 #endif 208 209 int 210 sys_execve(struct thread *td, struct execve_args *uap) 211 { 212 struct image_args args; 213 struct vmspace *oldvmspace; 214 int error; 215 216 error = pre_execve(td, &oldvmspace); 217 if (error != 0) 218 return (error); 219 error = exec_copyin_args(&args, uap->fname, UIO_USERSPACE, 220 uap->argv, uap->envv); 221 if (error == 0) 222 error = kern_execve(td, &args, NULL); 223 post_execve(td, error, oldvmspace); 224 return (error); 225 } 226 227 #ifndef _SYS_SYSPROTO_H_ 228 struct fexecve_args { 229 int fd; 230 char **argv; 231 char **envv; 232 } 233 #endif 234 int 235 sys_fexecve(struct thread *td, struct fexecve_args *uap) 236 { 237 struct image_args args; 238 struct vmspace *oldvmspace; 239 int error; 240 241 error = pre_execve(td, &oldvmspace); 242 if (error != 0) 243 return (error); 244 error = exec_copyin_args(&args, NULL, UIO_SYSSPACE, 245 uap->argv, uap->envv); 246 if (error == 0) { 247 args.fd = uap->fd; 248 error = kern_execve(td, &args, NULL); 249 } 250 post_execve(td, error, oldvmspace); 251 return (error); 252 } 253 254 #ifndef _SYS_SYSPROTO_H_ 255 struct __mac_execve_args { 256 char *fname; 257 char **argv; 258 char **envv; 259 struct mac *mac_p; 260 }; 261 #endif 262 263 int 264 sys___mac_execve(struct thread *td, struct __mac_execve_args *uap) 265 { 266 #ifdef MAC 267 struct image_args args; 268 struct vmspace *oldvmspace; 269 int error; 270 271 error = pre_execve(td, &oldvmspace); 272 if (error != 0) 273 return (error); 274 error = exec_copyin_args(&args, uap->fname, UIO_USERSPACE, 275 uap->argv, uap->envv); 276 if (error == 0) 277 error = kern_execve(td, &args, uap->mac_p); 278 post_execve(td, error, oldvmspace); 279 return (error); 280 #else 281 return (ENOSYS); 282 #endif 283 } 284 285 int 286 pre_execve(struct thread *td, struct vmspace **oldvmspace) 287 { 288 struct proc *p; 289 int error; 290 291 KASSERT(td == curthread, ("non-current thread %p", td)); 292 error = 0; 293 p = td->td_proc; 294 if ((p->p_flag & P_HADTHREADS) != 0) { 295 PROC_LOCK(p); 296 if (thread_single(p, SINGLE_BOUNDARY) != 0) 297 error = ERESTART; 298 PROC_UNLOCK(p); 299 } 300 KASSERT(error != 0 || (td->td_pflags & TDP_EXECVMSPC) == 0, 301 ("nested execve")); 302 *oldvmspace = p->p_vmspace; 303 return (error); 304 } 305 306 void 307 post_execve(struct thread *td, int error, struct vmspace *oldvmspace) 308 { 309 struct proc *p; 310 311 KASSERT(td == curthread, ("non-current thread %p", td)); 312 p = td->td_proc; 313 if ((p->p_flag & P_HADTHREADS) != 0) { 314 PROC_LOCK(p); 315 /* 316 * If success, we upgrade to SINGLE_EXIT state to 317 * force other threads to suicide. 318 */ 319 if (error == 0) 320 thread_single(p, SINGLE_EXIT); 321 else 322 thread_single_end(p, SINGLE_BOUNDARY); 323 PROC_UNLOCK(p); 324 } 325 if ((td->td_pflags & TDP_EXECVMSPC) != 0) { 326 KASSERT(p->p_vmspace != oldvmspace, 327 ("oldvmspace still used")); 328 vmspace_free(oldvmspace); 329 td->td_pflags &= ~TDP_EXECVMSPC; 330 } 331 } 332 333 /* 334 * XXX: kern_execve has the astonishing property of not always returning to 335 * the caller. If sufficiently bad things happen during the call to 336 * do_execve(), it can end up calling exit1(); as a result, callers must 337 * avoid doing anything which they might need to undo (e.g., allocating 338 * memory). 339 */ 340 int 341 kern_execve(struct thread *td, struct image_args *args, struct mac *mac_p) 342 { 343 344 AUDIT_ARG_ARGV(args->begin_argv, args->argc, 345 args->begin_envv - args->begin_argv); 346 AUDIT_ARG_ENVV(args->begin_envv, args->envc, 347 args->endp - args->begin_envv); 348 return (do_execve(td, args, mac_p)); 349 } 350 351 /* 352 * In-kernel implementation of execve(). All arguments are assumed to be 353 * userspace pointers from the passed thread. 354 */ 355 static int 356 do_execve(td, args, mac_p) 357 struct thread *td; 358 struct image_args *args; 359 struct mac *mac_p; 360 { 361 struct proc *p = td->td_proc; 362 struct nameidata nd; 363 struct ucred *oldcred; 364 struct uidinfo *euip = NULL; 365 register_t *stack_base; 366 int error, i; 367 struct image_params image_params, *imgp; 368 struct vattr attr; 369 int (*img_first)(struct image_params *); 370 struct pargs *oldargs = NULL, *newargs = NULL; 371 struct sigacts *oldsigacts = NULL, *newsigacts = NULL; 372 #ifdef KTRACE 373 struct vnode *tracevp = NULL; 374 struct ucred *tracecred = NULL; 375 #endif 376 struct vnode *oldtextvp = NULL, *newtextvp; 377 cap_rights_t rights; 378 int credential_changing; 379 int textset; 380 #ifdef MAC 381 struct label *interpvplabel = NULL; 382 int will_transition; 383 #endif 384 #ifdef HWPMC_HOOKS 385 struct pmckern_procexec pe; 386 #endif 387 static const char fexecv_proc_title[] = "(fexecv)"; 388 389 imgp = &image_params; 390 391 /* 392 * Lock the process and set the P_INEXEC flag to indicate that 393 * it should be left alone until we're done here. This is 394 * necessary to avoid race conditions - e.g. in ptrace() - 395 * that might allow a local user to illicitly obtain elevated 396 * privileges. 397 */ 398 PROC_LOCK(p); 399 KASSERT((p->p_flag & P_INEXEC) == 0, 400 ("%s(): process already has P_INEXEC flag", __func__)); 401 p->p_flag |= P_INEXEC; 402 PROC_UNLOCK(p); 403 404 /* 405 * Initialize part of the common data 406 */ 407 bzero(imgp, sizeof(*imgp)); 408 imgp->proc = p; 409 imgp->attr = &attr; 410 imgp->args = args; 411 oldcred = p->p_ucred; 412 413 #ifdef MAC 414 error = mac_execve_enter(imgp, mac_p); 415 if (error) 416 goto exec_fail; 417 #endif 418 419 /* 420 * Translate the file name. namei() returns a vnode pointer 421 * in ni_vp among other things. 422 * 423 * XXXAUDIT: It would be desirable to also audit the name of the 424 * interpreter if this is an interpreted binary. 425 */ 426 if (args->fname != NULL) { 427 NDINIT(&nd, LOOKUP, ISOPEN | LOCKLEAF | FOLLOW | SAVENAME 428 | AUDITVNODE1, UIO_SYSSPACE, args->fname, td); 429 } 430 431 SDT_PROBE1(proc, , , exec, args->fname); 432 433 interpret: 434 if (args->fname != NULL) { 435 #ifdef CAPABILITY_MODE 436 /* 437 * While capability mode can't reach this point via direct 438 * path arguments to execve(), we also don't allow 439 * interpreters to be used in capability mode (for now). 440 * Catch indirect lookups and return a permissions error. 441 */ 442 if (IN_CAPABILITY_MODE(td)) { 443 error = ECAPMODE; 444 goto exec_fail; 445 } 446 #endif 447 error = namei(&nd); 448 if (error) 449 goto exec_fail; 450 451 newtextvp = nd.ni_vp; 452 imgp->vp = newtextvp; 453 } else { 454 AUDIT_ARG_FD(args->fd); 455 /* 456 * Descriptors opened only with O_EXEC or O_RDONLY are allowed. 457 */ 458 error = fgetvp_exec(td, args->fd, 459 cap_rights_init(&rights, CAP_FEXECVE), &newtextvp); 460 if (error) 461 goto exec_fail; 462 vn_lock(newtextvp, LK_EXCLUSIVE | LK_RETRY); 463 AUDIT_ARG_VNODE1(newtextvp); 464 imgp->vp = newtextvp; 465 } 466 467 /* 468 * Check file permissions (also 'opens' file) 469 */ 470 error = exec_check_permissions(imgp); 471 if (error) 472 goto exec_fail_dealloc; 473 474 imgp->object = imgp->vp->v_object; 475 if (imgp->object != NULL) 476 vm_object_reference(imgp->object); 477 478 /* 479 * Set VV_TEXT now so no one can write to the executable while we're 480 * activating it. 481 * 482 * Remember if this was set before and unset it in case this is not 483 * actually an executable image. 484 */ 485 textset = VOP_IS_TEXT(imgp->vp); 486 VOP_SET_TEXT(imgp->vp); 487 488 error = exec_map_first_page(imgp); 489 if (error) 490 goto exec_fail_dealloc; 491 492 imgp->proc->p_osrel = 0; 493 494 /* 495 * Implement image setuid/setgid. 496 * 497 * Determine new credentials before attempting image activators 498 * so that it can be used by process_exec handlers to determine 499 * credential/setid changes. 500 * 501 * Don't honor setuid/setgid if the filesystem prohibits it or if 502 * the process is being traced. 503 * 504 * We disable setuid/setgid/etc in capability mode on the basis 505 * that most setugid applications are not written with that 506 * environment in mind, and will therefore almost certainly operate 507 * incorrectly. In principle there's no reason that setugid 508 * applications might not be useful in capability mode, so we may want 509 * to reconsider this conservative design choice in the future. 510 * 511 * XXXMAC: For the time being, use NOSUID to also prohibit 512 * transitions on the file system. 513 */ 514 credential_changing = 0; 515 credential_changing |= (attr.va_mode & S_ISUID) && 516 oldcred->cr_uid != attr.va_uid; 517 credential_changing |= (attr.va_mode & S_ISGID) && 518 oldcred->cr_gid != attr.va_gid; 519 #ifdef MAC 520 will_transition = mac_vnode_execve_will_transition(oldcred, imgp->vp, 521 interpvplabel, imgp); 522 credential_changing |= will_transition; 523 #endif 524 525 if (credential_changing && 526 #ifdef CAPABILITY_MODE 527 ((oldcred->cr_flags & CRED_FLAG_CAPMODE) == 0) && 528 #endif 529 (imgp->vp->v_mount->mnt_flag & MNT_NOSUID) == 0 && 530 (p->p_flag & P_TRACED) == 0) { 531 imgp->credential_setid = true; 532 VOP_UNLOCK(imgp->vp, 0); 533 imgp->newcred = crdup(oldcred); 534 if (attr.va_mode & S_ISUID) { 535 euip = uifind(attr.va_uid); 536 change_euid(imgp->newcred, euip); 537 } 538 vn_lock(imgp->vp, LK_EXCLUSIVE | LK_RETRY); 539 if (attr.va_mode & S_ISGID) 540 change_egid(imgp->newcred, attr.va_gid); 541 /* 542 * Implement correct POSIX saved-id behavior. 543 * 544 * XXXMAC: Note that the current logic will save the 545 * uid and gid if a MAC domain transition occurs, even 546 * though maybe it shouldn't. 547 */ 548 change_svuid(imgp->newcred, imgp->newcred->cr_uid); 549 change_svgid(imgp->newcred, imgp->newcred->cr_gid); 550 } else { 551 /* 552 * Implement correct POSIX saved-id behavior. 553 * 554 * XXX: It's not clear that the existing behavior is 555 * POSIX-compliant. A number of sources indicate that the 556 * saved uid/gid should only be updated if the new ruid is 557 * not equal to the old ruid, or the new euid is not equal 558 * to the old euid and the new euid is not equal to the old 559 * ruid. The FreeBSD code always updates the saved uid/gid. 560 * Also, this code uses the new (replaced) euid and egid as 561 * the source, which may or may not be the right ones to use. 562 */ 563 if (oldcred->cr_svuid != oldcred->cr_uid || 564 oldcred->cr_svgid != oldcred->cr_gid) { 565 VOP_UNLOCK(imgp->vp, 0); 566 imgp->newcred = crdup(oldcred); 567 vn_lock(imgp->vp, LK_EXCLUSIVE | LK_RETRY); 568 change_svuid(imgp->newcred, imgp->newcred->cr_uid); 569 change_svgid(imgp->newcred, imgp->newcred->cr_gid); 570 } 571 } 572 /* The new credentials are installed into the process later. */ 573 574 /* 575 * Do the best to calculate the full path to the image file. 576 */ 577 if (args->fname != NULL && args->fname[0] == '/') 578 imgp->execpath = args->fname; 579 else { 580 VOP_UNLOCK(imgp->vp, 0); 581 if (vn_fullpath(td, imgp->vp, &imgp->execpath, 582 &imgp->freepath) != 0) 583 imgp->execpath = args->fname; 584 vn_lock(imgp->vp, LK_EXCLUSIVE | LK_RETRY); 585 } 586 587 /* 588 * If the current process has a special image activator it 589 * wants to try first, call it. For example, emulating shell 590 * scripts differently. 591 */ 592 error = -1; 593 if ((img_first = imgp->proc->p_sysent->sv_imgact_try) != NULL) 594 error = img_first(imgp); 595 596 /* 597 * Loop through the list of image activators, calling each one. 598 * An activator returns -1 if there is no match, 0 on success, 599 * and an error otherwise. 600 */ 601 for (i = 0; error == -1 && execsw[i]; ++i) { 602 if (execsw[i]->ex_imgact == NULL || 603 execsw[i]->ex_imgact == img_first) { 604 continue; 605 } 606 error = (*execsw[i]->ex_imgact)(imgp); 607 } 608 609 if (error) { 610 if (error == -1) { 611 if (textset == 0) 612 VOP_UNSET_TEXT(imgp->vp); 613 error = ENOEXEC; 614 } 615 goto exec_fail_dealloc; 616 } 617 618 /* 619 * Special interpreter operation, cleanup and loop up to try to 620 * activate the interpreter. 621 */ 622 if (imgp->interpreted) { 623 exec_unmap_first_page(imgp); 624 /* 625 * VV_TEXT needs to be unset for scripts. There is a short 626 * period before we determine that something is a script where 627 * VV_TEXT will be set. The vnode lock is held over this 628 * entire period so nothing should illegitimately be blocked. 629 */ 630 VOP_UNSET_TEXT(imgp->vp); 631 /* free name buffer and old vnode */ 632 if (args->fname != NULL) 633 NDFREE(&nd, NDF_ONLY_PNBUF); 634 #ifdef MAC 635 mac_execve_interpreter_enter(newtextvp, &interpvplabel); 636 #endif 637 if (imgp->opened) { 638 VOP_CLOSE(newtextvp, FREAD, td->td_ucred, td); 639 imgp->opened = 0; 640 } 641 vput(newtextvp); 642 vm_object_deallocate(imgp->object); 643 imgp->object = NULL; 644 imgp->credential_setid = false; 645 if (imgp->newcred != NULL) { 646 crfree(imgp->newcred); 647 imgp->newcred = NULL; 648 } 649 imgp->execpath = NULL; 650 free(imgp->freepath, M_TEMP); 651 imgp->freepath = NULL; 652 /* set new name to that of the interpreter */ 653 NDINIT(&nd, LOOKUP, LOCKLEAF | FOLLOW | SAVENAME, 654 UIO_SYSSPACE, imgp->interpreter_name, td); 655 args->fname = imgp->interpreter_name; 656 goto interpret; 657 } 658 659 /* 660 * NB: We unlock the vnode here because it is believed that none 661 * of the sv_copyout_strings/sv_fixup operations require the vnode. 662 */ 663 VOP_UNLOCK(imgp->vp, 0); 664 665 if (disallow_high_osrel && 666 P_OSREL_MAJOR(p->p_osrel) > P_OSREL_MAJOR(__FreeBSD_version)) { 667 error = ENOEXEC; 668 uprintf("Osrel %d for image %s too high\n", p->p_osrel, 669 imgp->execpath != NULL ? imgp->execpath : "<unresolved>"); 670 vn_lock(imgp->vp, LK_SHARED | LK_RETRY); 671 goto exec_fail_dealloc; 672 } 673 674 /* 675 * Copy out strings (args and env) and initialize stack base 676 */ 677 if (p->p_sysent->sv_copyout_strings) 678 stack_base = (*p->p_sysent->sv_copyout_strings)(imgp); 679 else 680 stack_base = exec_copyout_strings(imgp); 681 682 /* 683 * If custom stack fixup routine present for this process 684 * let it do the stack setup. 685 * Else stuff argument count as first item on stack 686 */ 687 if (p->p_sysent->sv_fixup != NULL) 688 (*p->p_sysent->sv_fixup)(&stack_base, imgp); 689 else 690 suword(--stack_base, imgp->args->argc); 691 692 /* 693 * For security and other reasons, the file descriptor table cannot 694 * be shared after an exec. 695 */ 696 fdunshare(td); 697 /* close files on exec */ 698 fdcloseexec(td); 699 700 /* 701 * Malloc things before we need locks. 702 */ 703 i = imgp->args->begin_envv - imgp->args->begin_argv; 704 /* Cache arguments if they fit inside our allowance */ 705 if (ps_arg_cache_limit >= i + sizeof(struct pargs)) { 706 newargs = pargs_alloc(i); 707 bcopy(imgp->args->begin_argv, newargs->ar_args, i); 708 } 709 710 /* 711 * For security and other reasons, signal handlers cannot 712 * be shared after an exec. The new process gets a copy of the old 713 * handlers. In execsigs(), the new process will have its signals 714 * reset. 715 */ 716 if (sigacts_shared(p->p_sigacts)) { 717 oldsigacts = p->p_sigacts; 718 newsigacts = sigacts_alloc(); 719 sigacts_copy(newsigacts, oldsigacts); 720 } 721 722 vn_lock(imgp->vp, LK_SHARED | LK_RETRY); 723 724 PROC_LOCK(p); 725 if (oldsigacts) 726 p->p_sigacts = newsigacts; 727 /* Stop profiling */ 728 stopprofclock(p); 729 730 /* reset caught signals */ 731 execsigs(p); 732 733 /* name this process - nameiexec(p, ndp) */ 734 bzero(p->p_comm, sizeof(p->p_comm)); 735 if (args->fname) 736 bcopy(nd.ni_cnd.cn_nameptr, p->p_comm, 737 min(nd.ni_cnd.cn_namelen, MAXCOMLEN)); 738 else if (vn_commname(newtextvp, p->p_comm, sizeof(p->p_comm)) != 0) 739 bcopy(fexecv_proc_title, p->p_comm, sizeof(fexecv_proc_title)); 740 bcopy(p->p_comm, td->td_name, sizeof(td->td_name)); 741 #ifdef KTR 742 sched_clear_tdname(td); 743 #endif 744 745 /* 746 * mark as execed, wakeup the process that vforked (if any) and tell 747 * it that it now has its own resources back 748 */ 749 p->p_flag |= P_EXEC; 750 if ((p->p_flag2 & P2_NOTRACE_EXEC) == 0) 751 p->p_flag2 &= ~P2_NOTRACE; 752 if (p->p_flag & P_PPWAIT) { 753 p->p_flag &= ~(P_PPWAIT | P_PPTRACE); 754 cv_broadcast(&p->p_pwait); 755 /* STOPs are no longer ignored, arrange for AST */ 756 signotify(td); 757 } 758 759 /* 760 * Implement image setuid/setgid installation. 761 */ 762 if (imgp->credential_setid) { 763 /* 764 * Turn off syscall tracing for set-id programs, except for 765 * root. Record any set-id flags first to make sure that 766 * we do not regain any tracing during a possible block. 767 */ 768 setsugid(p); 769 770 #ifdef KTRACE 771 if (p->p_tracecred != NULL && 772 priv_check_cred(p->p_tracecred, PRIV_DEBUG_DIFFCRED, 0)) 773 ktrprocexec(p, &tracecred, &tracevp); 774 #endif 775 /* 776 * Close any file descriptors 0..2 that reference procfs, 777 * then make sure file descriptors 0..2 are in use. 778 * 779 * setugidsafety() may call closef() and then pfind() 780 * which may grab the process lock. 781 * fdcheckstd() may call falloc() which may block to 782 * allocate memory, so temporarily drop the process lock. 783 */ 784 PROC_UNLOCK(p); 785 VOP_UNLOCK(imgp->vp, 0); 786 setugidsafety(td); 787 error = fdcheckstd(td); 788 vn_lock(imgp->vp, LK_SHARED | LK_RETRY); 789 if (error != 0) 790 goto exec_fail_dealloc; 791 PROC_LOCK(p); 792 #ifdef MAC 793 if (will_transition) { 794 mac_vnode_execve_transition(oldcred, imgp->newcred, 795 imgp->vp, interpvplabel, imgp); 796 } 797 #endif 798 } else { 799 if (oldcred->cr_uid == oldcred->cr_ruid && 800 oldcred->cr_gid == oldcred->cr_rgid) 801 p->p_flag &= ~P_SUGID; 802 } 803 /* 804 * Set the new credentials. 805 */ 806 if (imgp->newcred != NULL) { 807 proc_set_cred(p, imgp->newcred); 808 crfree(oldcred); 809 oldcred = NULL; 810 } 811 812 /* 813 * Store the vp for use in procfs. This vnode was referenced by namei 814 * or fgetvp_exec. 815 */ 816 oldtextvp = p->p_textvp; 817 p->p_textvp = newtextvp; 818 819 #ifdef KDTRACE_HOOKS 820 /* 821 * Tell the DTrace fasttrap provider about the exec if it 822 * has declared an interest. 823 */ 824 if (dtrace_fasttrap_exec) 825 dtrace_fasttrap_exec(p); 826 #endif 827 828 /* 829 * Notify others that we exec'd, and clear the P_INEXEC flag 830 * as we're now a bona fide freshly-execed process. 831 */ 832 KNOTE_LOCKED(&p->p_klist, NOTE_EXEC); 833 p->p_flag &= ~P_INEXEC; 834 835 /* clear "fork but no exec" flag, as we _are_ execing */ 836 p->p_acflag &= ~AFORK; 837 838 /* 839 * Free any previous argument cache and replace it with 840 * the new argument cache, if any. 841 */ 842 oldargs = p->p_args; 843 p->p_args = newargs; 844 newargs = NULL; 845 846 #ifdef HWPMC_HOOKS 847 /* 848 * Check if system-wide sampling is in effect or if the 849 * current process is using PMCs. If so, do exec() time 850 * processing. This processing needs to happen AFTER the 851 * P_INEXEC flag is cleared. 852 * 853 * The proc lock needs to be released before taking the PMC 854 * SX. 855 */ 856 if (PMC_SYSTEM_SAMPLING_ACTIVE() || PMC_PROC_IS_USING_PMCS(p)) { 857 PROC_UNLOCK(p); 858 VOP_UNLOCK(imgp->vp, 0); 859 pe.pm_credentialschanged = credential_changing; 860 pe.pm_entryaddr = imgp->entry_addr; 861 862 PMC_CALL_HOOK_X(td, PMC_FN_PROCESS_EXEC, (void *) &pe); 863 vn_lock(imgp->vp, LK_SHARED | LK_RETRY); 864 } else 865 PROC_UNLOCK(p); 866 #else /* !HWPMC_HOOKS */ 867 PROC_UNLOCK(p); 868 #endif 869 870 /* Set values passed into the program in registers. */ 871 if (p->p_sysent->sv_setregs) 872 (*p->p_sysent->sv_setregs)(td, imgp, 873 (u_long)(uintptr_t)stack_base); 874 else 875 exec_setregs(td, imgp, (u_long)(uintptr_t)stack_base); 876 877 vfs_mark_atime(imgp->vp, td->td_ucred); 878 879 SDT_PROBE1(proc, , , exec__success, args->fname); 880 881 exec_fail_dealloc: 882 if (imgp->firstpage != NULL) 883 exec_unmap_first_page(imgp); 884 885 if (imgp->vp != NULL) { 886 if (args->fname) 887 NDFREE(&nd, NDF_ONLY_PNBUF); 888 if (imgp->opened) 889 VOP_CLOSE(imgp->vp, FREAD, td->td_ucred, td); 890 if (error != 0) 891 vput(imgp->vp); 892 else 893 VOP_UNLOCK(imgp->vp, 0); 894 } 895 896 if (imgp->object != NULL) 897 vm_object_deallocate(imgp->object); 898 899 free(imgp->freepath, M_TEMP); 900 901 if (error == 0) { 902 PROC_LOCK(p); 903 if (p->p_ptevents & PTRACE_EXEC) 904 td->td_dbgflags |= TDB_EXEC; 905 PROC_UNLOCK(p); 906 907 /* 908 * Stop the process here if its stop event mask has 909 * the S_EXEC bit set. 910 */ 911 STOPEVENT(p, S_EXEC, 0); 912 } else { 913 exec_fail: 914 /* we're done here, clear P_INEXEC */ 915 PROC_LOCK(p); 916 p->p_flag &= ~P_INEXEC; 917 PROC_UNLOCK(p); 918 919 SDT_PROBE1(proc, , , exec__failure, error); 920 } 921 922 if (imgp->newcred != NULL && oldcred != NULL) 923 crfree(imgp->newcred); 924 925 #ifdef MAC 926 mac_execve_exit(imgp); 927 mac_execve_interpreter_exit(interpvplabel); 928 #endif 929 exec_free_args(args); 930 931 /* 932 * Handle deferred decrement of ref counts. 933 */ 934 if (oldtextvp != NULL) 935 vrele(oldtextvp); 936 #ifdef KTRACE 937 if (tracevp != NULL) 938 vrele(tracevp); 939 if (tracecred != NULL) 940 crfree(tracecred); 941 #endif 942 pargs_drop(oldargs); 943 pargs_drop(newargs); 944 if (oldsigacts != NULL) 945 sigacts_free(oldsigacts); 946 if (euip != NULL) 947 uifree(euip); 948 949 if (error && imgp->vmspace_destroyed) { 950 /* sorry, no more process anymore. exit gracefully */ 951 exit1(td, W_EXITCODE(0, SIGABRT)); 952 /* NOT REACHED */ 953 } 954 955 #ifdef KTRACE 956 if (error == 0) 957 ktrprocctor(p); 958 #endif 959 960 return (error); 961 } 962 963 int 964 exec_map_first_page(imgp) 965 struct image_params *imgp; 966 { 967 int rv, i; 968 int initial_pagein; 969 vm_page_t ma[VM_INITIAL_PAGEIN]; 970 vm_object_t object; 971 972 if (imgp->firstpage != NULL) 973 exec_unmap_first_page(imgp); 974 975 object = imgp->vp->v_object; 976 if (object == NULL) 977 return (EACCES); 978 VM_OBJECT_WLOCK(object); 979 #if VM_NRESERVLEVEL > 0 980 if ((object->flags & OBJ_COLORED) == 0) { 981 object->flags |= OBJ_COLORED; 982 object->pg_color = 0; 983 } 984 #endif 985 ma[0] = vm_page_grab(object, 0, VM_ALLOC_NORMAL); 986 if (ma[0]->valid != VM_PAGE_BITS_ALL) { 987 initial_pagein = VM_INITIAL_PAGEIN; 988 if (initial_pagein > object->size) 989 initial_pagein = object->size; 990 for (i = 1; i < initial_pagein; i++) { 991 if ((ma[i] = vm_page_next(ma[i - 1])) != NULL) { 992 if (ma[i]->valid) 993 break; 994 if (vm_page_tryxbusy(ma[i])) 995 break; 996 } else { 997 ma[i] = vm_page_alloc(object, i, 998 VM_ALLOC_NORMAL | VM_ALLOC_IFNOTCACHED); 999 if (ma[i] == NULL) 1000 break; 1001 } 1002 } 1003 initial_pagein = i; 1004 rv = vm_pager_get_pages(object, ma, initial_pagein, 0); 1005 ma[0] = vm_page_lookup(object, 0); 1006 if ((rv != VM_PAGER_OK) || (ma[0] == NULL)) { 1007 if (ma[0] != NULL) { 1008 vm_page_lock(ma[0]); 1009 vm_page_free(ma[0]); 1010 vm_page_unlock(ma[0]); 1011 } 1012 VM_OBJECT_WUNLOCK(object); 1013 return (EIO); 1014 } 1015 } 1016 vm_page_xunbusy(ma[0]); 1017 vm_page_lock(ma[0]); 1018 vm_page_hold(ma[0]); 1019 vm_page_activate(ma[0]); 1020 vm_page_unlock(ma[0]); 1021 VM_OBJECT_WUNLOCK(object); 1022 1023 imgp->firstpage = sf_buf_alloc(ma[0], 0); 1024 imgp->image_header = (char *)sf_buf_kva(imgp->firstpage); 1025 1026 return (0); 1027 } 1028 1029 void 1030 exec_unmap_first_page(imgp) 1031 struct image_params *imgp; 1032 { 1033 vm_page_t m; 1034 1035 if (imgp->firstpage != NULL) { 1036 m = sf_buf_page(imgp->firstpage); 1037 sf_buf_free(imgp->firstpage); 1038 imgp->firstpage = NULL; 1039 vm_page_lock(m); 1040 vm_page_unhold(m); 1041 vm_page_unlock(m); 1042 } 1043 } 1044 1045 /* 1046 * Destroy old address space, and allocate a new stack. 1047 * The new stack is only sgrowsiz large because it is grown 1048 * automatically on a page fault. 1049 */ 1050 int 1051 exec_new_vmspace(imgp, sv) 1052 struct image_params *imgp; 1053 struct sysentvec *sv; 1054 { 1055 int error; 1056 struct proc *p = imgp->proc; 1057 struct vmspace *vmspace = p->p_vmspace; 1058 vm_object_t obj; 1059 struct rlimit rlim_stack; 1060 vm_offset_t sv_minuser, stack_addr; 1061 vm_map_t map; 1062 u_long ssiz; 1063 1064 imgp->vmspace_destroyed = 1; 1065 imgp->sysent = sv; 1066 1067 /* May be called with Giant held */ 1068 EVENTHANDLER_INVOKE(process_exec, p, imgp); 1069 1070 /* 1071 * Blow away entire process VM, if address space not shared, 1072 * otherwise, create a new VM space so that other threads are 1073 * not disrupted 1074 */ 1075 map = &vmspace->vm_map; 1076 if (map_at_zero) 1077 sv_minuser = sv->sv_minuser; 1078 else 1079 sv_minuser = MAX(sv->sv_minuser, PAGE_SIZE); 1080 if (vmspace->vm_refcnt == 1 && vm_map_min(map) == sv_minuser && 1081 vm_map_max(map) == sv->sv_maxuser) { 1082 shmexit(vmspace); 1083 pmap_remove_pages(vmspace_pmap(vmspace)); 1084 vm_map_remove(map, vm_map_min(map), vm_map_max(map)); 1085 /* An exec terminates mlockall(MCL_FUTURE). */ 1086 vm_map_lock(map); 1087 vm_map_modflags(map, 0, MAP_WIREFUTURE); 1088 vm_map_unlock(map); 1089 } else { 1090 error = vmspace_exec(p, sv_minuser, sv->sv_maxuser); 1091 if (error) 1092 return (error); 1093 vmspace = p->p_vmspace; 1094 map = &vmspace->vm_map; 1095 } 1096 1097 /* Map a shared page */ 1098 obj = sv->sv_shared_page_obj; 1099 if (obj != NULL) { 1100 vm_object_reference(obj); 1101 error = vm_map_fixed(map, obj, 0, 1102 sv->sv_shared_page_base, sv->sv_shared_page_len, 1103 VM_PROT_READ | VM_PROT_EXECUTE, 1104 VM_PROT_READ | VM_PROT_EXECUTE, 1105 MAP_INHERIT_SHARE | MAP_ACC_NO_CHARGE); 1106 if (error != KERN_SUCCESS) { 1107 vm_object_deallocate(obj); 1108 return (vm_mmap_to_errno(error)); 1109 } 1110 } 1111 1112 /* Allocate a new stack */ 1113 if (imgp->stack_sz != 0) { 1114 ssiz = trunc_page(imgp->stack_sz); 1115 PROC_LOCK(p); 1116 lim_rlimit(p, RLIMIT_STACK, &rlim_stack); 1117 PROC_UNLOCK(p); 1118 if (ssiz > rlim_stack.rlim_max) 1119 ssiz = rlim_stack.rlim_max; 1120 if (ssiz > rlim_stack.rlim_cur) { 1121 rlim_stack.rlim_cur = ssiz; 1122 kern_setrlimit(curthread, RLIMIT_STACK, &rlim_stack); 1123 } 1124 } else if (sv->sv_maxssiz != NULL) { 1125 ssiz = *sv->sv_maxssiz; 1126 } else { 1127 ssiz = maxssiz; 1128 } 1129 stack_addr = sv->sv_usrstack - ssiz; 1130 error = vm_map_stack(map, stack_addr, (vm_size_t)ssiz, 1131 obj != NULL && imgp->stack_prot != 0 ? imgp->stack_prot : 1132 sv->sv_stackprot, VM_PROT_ALL, MAP_STACK_GROWS_DOWN); 1133 if (error != KERN_SUCCESS) 1134 return (vm_mmap_to_errno(error)); 1135 1136 #ifdef __ia64__ 1137 /* Allocate a new register stack */ 1138 error = vm_map_stack(map, IA64_BACKINGSTORE, (vm_size_t)ssiz, 1139 sv->sv_stackprot, VM_PROT_ALL, MAP_STACK_GROWS_UP); 1140 if (error) 1141 return (error); 1142 #endif 1143 1144 /* vm_ssize and vm_maxsaddr are somewhat antiquated concepts in the 1145 * VM_STACK case, but they are still used to monitor the size of the 1146 * process stack so we can check the stack rlimit. 1147 */ 1148 vmspace->vm_ssize = sgrowsiz >> PAGE_SHIFT; 1149 vmspace->vm_maxsaddr = (char *)stack_addr; 1150 1151 return (0); 1152 } 1153 1154 /* 1155 * Copy out argument and environment strings from the old process address 1156 * space into the temporary string buffer. 1157 */ 1158 int 1159 exec_copyin_args(struct image_args *args, char *fname, 1160 enum uio_seg segflg, char **argv, char **envv) 1161 { 1162 u_long argp, envp; 1163 int error; 1164 size_t length; 1165 1166 bzero(args, sizeof(*args)); 1167 if (argv == NULL) 1168 return (EFAULT); 1169 1170 /* 1171 * Allocate demand-paged memory for the file name, argument, and 1172 * environment strings. 1173 */ 1174 error = exec_alloc_args(args); 1175 if (error != 0) 1176 return (error); 1177 1178 /* 1179 * Copy the file name. 1180 */ 1181 if (fname != NULL) { 1182 args->fname = args->buf; 1183 error = (segflg == UIO_SYSSPACE) ? 1184 copystr(fname, args->fname, PATH_MAX, &length) : 1185 copyinstr(fname, args->fname, PATH_MAX, &length); 1186 if (error != 0) 1187 goto err_exit; 1188 } else 1189 length = 0; 1190 1191 args->begin_argv = args->buf + length; 1192 args->endp = args->begin_argv; 1193 args->stringspace = ARG_MAX; 1194 1195 /* 1196 * extract arguments first 1197 */ 1198 for (;;) { 1199 error = fueword(argv++, &argp); 1200 if (error == -1) { 1201 error = EFAULT; 1202 goto err_exit; 1203 } 1204 if (argp == 0) 1205 break; 1206 error = copyinstr((void *)(uintptr_t)argp, args->endp, 1207 args->stringspace, &length); 1208 if (error != 0) { 1209 if (error == ENAMETOOLONG) 1210 error = E2BIG; 1211 goto err_exit; 1212 } 1213 args->stringspace -= length; 1214 args->endp += length; 1215 args->argc++; 1216 } 1217 1218 args->begin_envv = args->endp; 1219 1220 /* 1221 * extract environment strings 1222 */ 1223 if (envv) { 1224 for (;;) { 1225 error = fueword(envv++, &envp); 1226 if (error == -1) { 1227 error = EFAULT; 1228 goto err_exit; 1229 } 1230 if (envp == 0) 1231 break; 1232 error = copyinstr((void *)(uintptr_t)envp, 1233 args->endp, args->stringspace, &length); 1234 if (error != 0) { 1235 if (error == ENAMETOOLONG) 1236 error = E2BIG; 1237 goto err_exit; 1238 } 1239 args->stringspace -= length; 1240 args->endp += length; 1241 args->envc++; 1242 } 1243 } 1244 1245 return (0); 1246 1247 err_exit: 1248 exec_free_args(args); 1249 return (error); 1250 } 1251 1252 /* 1253 * Allocate temporary demand-paged, zero-filled memory for the file name, 1254 * argument, and environment strings. Returns zero if the allocation succeeds 1255 * and ENOMEM otherwise. 1256 */ 1257 int 1258 exec_alloc_args(struct image_args *args) 1259 { 1260 1261 args->buf = (char *)kmap_alloc_wait(exec_map, PATH_MAX + ARG_MAX); 1262 return (args->buf != NULL ? 0 : ENOMEM); 1263 } 1264 1265 void 1266 exec_free_args(struct image_args *args) 1267 { 1268 1269 if (args->buf != NULL) { 1270 kmap_free_wakeup(exec_map, (vm_offset_t)args->buf, 1271 PATH_MAX + ARG_MAX); 1272 args->buf = NULL; 1273 } 1274 if (args->fname_buf != NULL) { 1275 free(args->fname_buf, M_TEMP); 1276 args->fname_buf = NULL; 1277 } 1278 } 1279 1280 /* 1281 * Copy strings out to the new process address space, constructing new arg 1282 * and env vector tables. Return a pointer to the base so that it can be used 1283 * as the initial stack pointer. 1284 */ 1285 register_t * 1286 exec_copyout_strings(imgp) 1287 struct image_params *imgp; 1288 { 1289 int argc, envc; 1290 char **vectp; 1291 char *stringp; 1292 uintptr_t destp; 1293 register_t *stack_base; 1294 struct ps_strings *arginfo; 1295 struct proc *p; 1296 size_t execpath_len; 1297 int szsigcode, szps; 1298 char canary[sizeof(long) * 8]; 1299 1300 szps = sizeof(pagesizes[0]) * MAXPAGESIZES; 1301 /* 1302 * Calculate string base and vector table pointers. 1303 * Also deal with signal trampoline code for this exec type. 1304 */ 1305 if (imgp->execpath != NULL && imgp->auxargs != NULL) 1306 execpath_len = strlen(imgp->execpath) + 1; 1307 else 1308 execpath_len = 0; 1309 p = imgp->proc; 1310 szsigcode = 0; 1311 arginfo = (struct ps_strings *)p->p_sysent->sv_psstrings; 1312 if (p->p_sysent->sv_sigcode_base == 0) { 1313 if (p->p_sysent->sv_szsigcode != NULL) 1314 szsigcode = *(p->p_sysent->sv_szsigcode); 1315 } 1316 destp = (uintptr_t)arginfo; 1317 1318 /* 1319 * install sigcode 1320 */ 1321 if (szsigcode != 0) { 1322 destp -= szsigcode; 1323 destp = rounddown2(destp, sizeof(void *)); 1324 copyout(p->p_sysent->sv_sigcode, (void *)destp, szsigcode); 1325 } 1326 1327 /* 1328 * Copy the image path for the rtld. 1329 */ 1330 if (execpath_len != 0) { 1331 destp -= execpath_len; 1332 imgp->execpathp = destp; 1333 copyout(imgp->execpath, (void *)destp, execpath_len); 1334 } 1335 1336 /* 1337 * Prepare the canary for SSP. 1338 */ 1339 arc4rand(canary, sizeof(canary), 0); 1340 destp -= sizeof(canary); 1341 imgp->canary = destp; 1342 copyout(canary, (void *)destp, sizeof(canary)); 1343 imgp->canarylen = sizeof(canary); 1344 1345 /* 1346 * Prepare the pagesizes array. 1347 */ 1348 destp -= szps; 1349 destp = rounddown2(destp, sizeof(void *)); 1350 imgp->pagesizes = destp; 1351 copyout(pagesizes, (void *)destp, szps); 1352 imgp->pagesizeslen = szps; 1353 1354 destp -= ARG_MAX - imgp->args->stringspace; 1355 destp = rounddown2(destp, sizeof(void *)); 1356 1357 /* 1358 * If we have a valid auxargs ptr, prepare some room 1359 * on the stack. 1360 */ 1361 if (imgp->auxargs) { 1362 /* 1363 * 'AT_COUNT*2' is size for the ELF Auxargs data. This is for 1364 * lower compatibility. 1365 */ 1366 imgp->auxarg_size = (imgp->auxarg_size) ? imgp->auxarg_size : 1367 (AT_COUNT * 2); 1368 /* 1369 * The '+ 2' is for the null pointers at the end of each of 1370 * the arg and env vector sets,and imgp->auxarg_size is room 1371 * for argument of Runtime loader. 1372 */ 1373 vectp = (char **)(destp - (imgp->args->argc + 1374 imgp->args->envc + 2 + imgp->auxarg_size) 1375 * sizeof(char *)); 1376 } else { 1377 /* 1378 * The '+ 2' is for the null pointers at the end of each of 1379 * the arg and env vector sets 1380 */ 1381 vectp = (char **)(destp - (imgp->args->argc + imgp->args->envc 1382 + 2) * sizeof(char *)); 1383 } 1384 1385 /* 1386 * vectp also becomes our initial stack base 1387 */ 1388 stack_base = (register_t *)vectp; 1389 1390 stringp = imgp->args->begin_argv; 1391 argc = imgp->args->argc; 1392 envc = imgp->args->envc; 1393 1394 /* 1395 * Copy out strings - arguments and environment. 1396 */ 1397 copyout(stringp, (void *)destp, ARG_MAX - imgp->args->stringspace); 1398 1399 /* 1400 * Fill in "ps_strings" struct for ps, w, etc. 1401 */ 1402 suword(&arginfo->ps_argvstr, (long)(intptr_t)vectp); 1403 suword32(&arginfo->ps_nargvstr, argc); 1404 1405 /* 1406 * Fill in argument portion of vector table. 1407 */ 1408 for (; argc > 0; --argc) { 1409 suword(vectp++, (long)(intptr_t)destp); 1410 while (*stringp++ != 0) 1411 destp++; 1412 destp++; 1413 } 1414 1415 /* a null vector table pointer separates the argp's from the envp's */ 1416 suword(vectp++, 0); 1417 1418 suword(&arginfo->ps_envstr, (long)(intptr_t)vectp); 1419 suword32(&arginfo->ps_nenvstr, envc); 1420 1421 /* 1422 * Fill in environment portion of vector table. 1423 */ 1424 for (; envc > 0; --envc) { 1425 suword(vectp++, (long)(intptr_t)destp); 1426 while (*stringp++ != 0) 1427 destp++; 1428 destp++; 1429 } 1430 1431 /* end of vector table is a null pointer */ 1432 suword(vectp, 0); 1433 1434 return (stack_base); 1435 } 1436 1437 /* 1438 * Check permissions of file to execute. 1439 * Called with imgp->vp locked. 1440 * Return 0 for success or error code on failure. 1441 */ 1442 int 1443 exec_check_permissions(imgp) 1444 struct image_params *imgp; 1445 { 1446 struct vnode *vp = imgp->vp; 1447 struct vattr *attr = imgp->attr; 1448 struct thread *td; 1449 int error, writecount; 1450 1451 td = curthread; 1452 1453 /* Get file attributes */ 1454 error = VOP_GETATTR(vp, attr, td->td_ucred); 1455 if (error) 1456 return (error); 1457 1458 #ifdef MAC 1459 error = mac_vnode_check_exec(td->td_ucred, imgp->vp, imgp); 1460 if (error) 1461 return (error); 1462 #endif 1463 1464 /* 1465 * 1) Check if file execution is disabled for the filesystem that 1466 * this file resides on. 1467 * 2) Ensure that at least one execute bit is on. Otherwise, a 1468 * privileged user will always succeed, and we don't want this 1469 * to happen unless the file really is executable. 1470 * 3) Ensure that the file is a regular file. 1471 */ 1472 if ((vp->v_mount->mnt_flag & MNT_NOEXEC) || 1473 (attr->va_mode & (S_IXUSR | S_IXGRP | S_IXOTH)) == 0 || 1474 (attr->va_type != VREG)) 1475 return (EACCES); 1476 1477 /* 1478 * Zero length files can't be exec'd 1479 */ 1480 if (attr->va_size == 0) 1481 return (ENOEXEC); 1482 1483 /* 1484 * Check for execute permission to file based on current credentials. 1485 */ 1486 error = VOP_ACCESS(vp, VEXEC, td->td_ucred, td); 1487 if (error) 1488 return (error); 1489 1490 /* 1491 * Check number of open-for-writes on the file and deny execution 1492 * if there are any. 1493 */ 1494 error = VOP_GET_WRITECOUNT(vp, &writecount); 1495 if (error != 0) 1496 return (error); 1497 if (writecount != 0) 1498 return (ETXTBSY); 1499 1500 /* 1501 * Call filesystem specific open routine (which does nothing in the 1502 * general case). 1503 */ 1504 error = VOP_OPEN(vp, FREAD, td->td_ucred, td, NULL); 1505 if (error == 0) 1506 imgp->opened = 1; 1507 return (error); 1508 } 1509 1510 /* 1511 * Exec handler registration 1512 */ 1513 int 1514 exec_register(execsw_arg) 1515 const struct execsw *execsw_arg; 1516 { 1517 const struct execsw **es, **xs, **newexecsw; 1518 int count = 2; /* New slot and trailing NULL */ 1519 1520 if (execsw) 1521 for (es = execsw; *es; es++) 1522 count++; 1523 newexecsw = malloc(count * sizeof(*es), M_TEMP, M_WAITOK); 1524 xs = newexecsw; 1525 if (execsw) 1526 for (es = execsw; *es; es++) 1527 *xs++ = *es; 1528 *xs++ = execsw_arg; 1529 *xs = NULL; 1530 if (execsw) 1531 free(execsw, M_TEMP); 1532 execsw = newexecsw; 1533 return (0); 1534 } 1535 1536 int 1537 exec_unregister(execsw_arg) 1538 const struct execsw *execsw_arg; 1539 { 1540 const struct execsw **es, **xs, **newexecsw; 1541 int count = 1; 1542 1543 if (execsw == NULL) 1544 panic("unregister with no handlers left?\n"); 1545 1546 for (es = execsw; *es; es++) { 1547 if (*es == execsw_arg) 1548 break; 1549 } 1550 if (*es == NULL) 1551 return (ENOENT); 1552 for (es = execsw; *es; es++) 1553 if (*es != execsw_arg) 1554 count++; 1555 newexecsw = malloc(count * sizeof(*es), M_TEMP, M_WAITOK); 1556 xs = newexecsw; 1557 for (es = execsw; *es; es++) 1558 if (*es != execsw_arg) 1559 *xs++ = *es; 1560 *xs = NULL; 1561 if (execsw) 1562 free(execsw, M_TEMP); 1563 execsw = newexecsw; 1564 return (0); 1565 }
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