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_capsicum.h" 31 #include "opt_hwpmc_hooks.h" 32 #include "opt_ktrace.h" 33 #include "opt_vm.h" 34 35 #include <sys/param.h> 36 #include <sys/capsicum.h> 37 #include <sys/systm.h> 38 #include <sys/eventhandler.h> 39 #include <sys/lock.h> 40 #include <sys/mutex.h> 41 #include <sys/sysproto.h> 42 #include <sys/signalvar.h> 43 #include <sys/kernel.h> 44 #include <sys/mount.h> 45 #include <sys/filedesc.h> 46 #include <sys/fcntl.h> 47 #include <sys/acct.h> 48 #include <sys/exec.h> 49 #include <sys/imgact.h> 50 #include <sys/imgact_elf.h> 51 #include <sys/wait.h> 52 #include <sys/malloc.h> 53 #include <sys/priv.h> 54 #include <sys/proc.h> 55 #include <sys/pioctl.h> 56 #include <sys/namei.h> 57 #include <sys/resourcevar.h> 58 #include <sys/rwlock.h> 59 #include <sys/sched.h> 60 #include <sys/sdt.h> 61 #include <sys/sf_buf.h> 62 #include <sys/syscallsubr.h> 63 #include <sys/sysent.h> 64 #include <sys/shm.h> 65 #include <sys/sysctl.h> 66 #include <sys/vnode.h> 67 #include <sys/stat.h> 68 #ifdef KTRACE 69 #include <sys/ktrace.h> 70 #endif 71 72 #include <vm/vm.h> 73 #include <vm/vm_param.h> 74 #include <vm/pmap.h> 75 #include <vm/vm_page.h> 76 #include <vm/vm_map.h> 77 #include <vm/vm_kern.h> 78 #include <vm/vm_extern.h> 79 #include <vm/vm_object.h> 80 #include <vm/vm_pager.h> 81 82 #ifdef HWPMC_HOOKS 83 #include <sys/pmckern.h> 84 #endif 85 86 #include <machine/reg.h> 87 88 #include <security/audit/audit.h> 89 #include <security/mac/mac_framework.h> 90 91 #ifdef KDTRACE_HOOKS 92 #include <sys/dtrace_bsd.h> 93 dtrace_execexit_func_t dtrace_fasttrap_exec; 94 #endif 95 96 SDT_PROVIDER_DECLARE(proc); 97 SDT_PROBE_DEFINE1(proc, , , exec, "char *"); 98 SDT_PROBE_DEFINE1(proc, , , exec__failure, "int"); 99 SDT_PROBE_DEFINE1(proc, , , exec__success, "char *"); 100 101 MALLOC_DEFINE(M_PARGS, "proc-args", "Process arguments"); 102 103 int coredump_pack_fileinfo = 1; 104 SYSCTL_INT(_kern, OID_AUTO, coredump_pack_fileinfo, CTLFLAG_RWTUN, 105 &coredump_pack_fileinfo, 0, 106 "Enable file path packing in 'procstat -f' coredump notes"); 107 108 int coredump_pack_vmmapinfo = 1; 109 SYSCTL_INT(_kern, OID_AUTO, coredump_pack_vmmapinfo, CTLFLAG_RWTUN, 110 &coredump_pack_vmmapinfo, 0, 111 "Enable file path packing in 'procstat -v' coredump notes"); 112 113 static int sysctl_kern_ps_strings(SYSCTL_HANDLER_ARGS); 114 static int sysctl_kern_usrstack(SYSCTL_HANDLER_ARGS); 115 static int sysctl_kern_stackprot(SYSCTL_HANDLER_ARGS); 116 static int do_execve(struct thread *td, struct image_args *args, 117 struct mac *mac_p); 118 119 /* XXX This should be vm_size_t. */ 120 SYSCTL_PROC(_kern, KERN_PS_STRINGS, ps_strings, CTLTYPE_ULONG|CTLFLAG_RD, 121 NULL, 0, sysctl_kern_ps_strings, "LU", ""); 122 123 /* XXX This should be vm_size_t. */ 124 SYSCTL_PROC(_kern, KERN_USRSTACK, usrstack, CTLTYPE_ULONG|CTLFLAG_RD| 125 CTLFLAG_CAPRD, NULL, 0, sysctl_kern_usrstack, "LU", ""); 126 127 SYSCTL_PROC(_kern, OID_AUTO, stackprot, CTLTYPE_INT|CTLFLAG_RD, 128 NULL, 0, sysctl_kern_stackprot, "I", ""); 129 130 u_long ps_arg_cache_limit = PAGE_SIZE / 16; 131 SYSCTL_ULONG(_kern, OID_AUTO, ps_arg_cache_limit, CTLFLAG_RW, 132 &ps_arg_cache_limit, 0, ""); 133 134 static int disallow_high_osrel; 135 SYSCTL_INT(_kern, OID_AUTO, disallow_high_osrel, CTLFLAG_RW, 136 &disallow_high_osrel, 0, 137 "Disallow execution of binaries built for higher version of the world"); 138 139 static int map_at_zero = 0; 140 SYSCTL_INT(_security_bsd, OID_AUTO, map_at_zero, CTLFLAG_RWTUN, &map_at_zero, 0, 141 "Permit processes to map an object at virtual address 0."); 142 143 static int 144 sysctl_kern_ps_strings(SYSCTL_HANDLER_ARGS) 145 { 146 struct proc *p; 147 int error; 148 149 p = curproc; 150 #ifdef SCTL_MASK32 151 if (req->flags & SCTL_MASK32) { 152 unsigned int val; 153 val = (unsigned int)p->p_sysent->sv_psstrings; 154 error = SYSCTL_OUT(req, &val, sizeof(val)); 155 } else 156 #endif 157 error = SYSCTL_OUT(req, &p->p_sysent->sv_psstrings, 158 sizeof(p->p_sysent->sv_psstrings)); 159 return error; 160 } 161 162 static int 163 sysctl_kern_usrstack(SYSCTL_HANDLER_ARGS) 164 { 165 struct proc *p; 166 int error; 167 168 p = curproc; 169 #ifdef SCTL_MASK32 170 if (req->flags & SCTL_MASK32) { 171 unsigned int val; 172 val = (unsigned int)p->p_sysent->sv_usrstack; 173 error = SYSCTL_OUT(req, &val, sizeof(val)); 174 } else 175 #endif 176 error = SYSCTL_OUT(req, &p->p_sysent->sv_usrstack, 177 sizeof(p->p_sysent->sv_usrstack)); 178 return error; 179 } 180 181 static int 182 sysctl_kern_stackprot(SYSCTL_HANDLER_ARGS) 183 { 184 struct proc *p; 185 186 p = curproc; 187 return (SYSCTL_OUT(req, &p->p_sysent->sv_stackprot, 188 sizeof(p->p_sysent->sv_stackprot))); 189 } 190 191 /* 192 * Each of the items is a pointer to a `const struct execsw', hence the 193 * double pointer here. 194 */ 195 static const struct execsw **execsw; 196 197 #ifndef _SYS_SYSPROTO_H_ 198 struct execve_args { 199 char *fname; 200 char **argv; 201 char **envv; 202 }; 203 #endif 204 205 int 206 sys_execve(struct thread *td, struct execve_args *uap) 207 { 208 struct image_args args; 209 struct vmspace *oldvmspace; 210 int error; 211 212 error = pre_execve(td, &oldvmspace); 213 if (error != 0) 214 return (error); 215 error = exec_copyin_args(&args, uap->fname, UIO_USERSPACE, 216 uap->argv, uap->envv); 217 if (error == 0) 218 error = kern_execve(td, &args, NULL); 219 post_execve(td, error, oldvmspace); 220 return (error); 221 } 222 223 #ifndef _SYS_SYSPROTO_H_ 224 struct fexecve_args { 225 int fd; 226 char **argv; 227 char **envv; 228 } 229 #endif 230 int 231 sys_fexecve(struct thread *td, struct fexecve_args *uap) 232 { 233 struct image_args args; 234 struct vmspace *oldvmspace; 235 int error; 236 237 error = pre_execve(td, &oldvmspace); 238 if (error != 0) 239 return (error); 240 error = exec_copyin_args(&args, NULL, UIO_SYSSPACE, 241 uap->argv, uap->envv); 242 if (error == 0) { 243 args.fd = uap->fd; 244 error = kern_execve(td, &args, NULL); 245 } 246 post_execve(td, error, oldvmspace); 247 return (error); 248 } 249 250 #ifndef _SYS_SYSPROTO_H_ 251 struct __mac_execve_args { 252 char *fname; 253 char **argv; 254 char **envv; 255 struct mac *mac_p; 256 }; 257 #endif 258 259 int 260 sys___mac_execve(struct thread *td, struct __mac_execve_args *uap) 261 { 262 #ifdef MAC 263 struct image_args args; 264 struct vmspace *oldvmspace; 265 int error; 266 267 error = pre_execve(td, &oldvmspace); 268 if (error != 0) 269 return (error); 270 error = exec_copyin_args(&args, uap->fname, UIO_USERSPACE, 271 uap->argv, uap->envv); 272 if (error == 0) 273 error = kern_execve(td, &args, uap->mac_p); 274 post_execve(td, error, oldvmspace); 275 return (error); 276 #else 277 return (ENOSYS); 278 #endif 279 } 280 281 int 282 pre_execve(struct thread *td, struct vmspace **oldvmspace) 283 { 284 struct proc *p; 285 int error; 286 287 KASSERT(td == curthread, ("non-current thread %p", td)); 288 error = 0; 289 p = td->td_proc; 290 if ((p->p_flag & P_HADTHREADS) != 0) { 291 PROC_LOCK(p); 292 if (thread_single(p, SINGLE_BOUNDARY) != 0) 293 error = ERESTART; 294 PROC_UNLOCK(p); 295 } 296 KASSERT(error != 0 || (td->td_pflags & TDP_EXECVMSPC) == 0, 297 ("nested execve")); 298 *oldvmspace = p->p_vmspace; 299 return (error); 300 } 301 302 void 303 post_execve(struct thread *td, int error, struct vmspace *oldvmspace) 304 { 305 struct proc *p; 306 307 KASSERT(td == curthread, ("non-current thread %p", td)); 308 p = td->td_proc; 309 if ((p->p_flag & P_HADTHREADS) != 0) { 310 PROC_LOCK(p); 311 /* 312 * If success, we upgrade to SINGLE_EXIT state to 313 * force other threads to suicide. 314 */ 315 if (error == 0) 316 thread_single(p, SINGLE_EXIT); 317 else 318 thread_single_end(p, SINGLE_BOUNDARY); 319 PROC_UNLOCK(p); 320 } 321 if ((td->td_pflags & TDP_EXECVMSPC) != 0) { 322 KASSERT(p->p_vmspace != oldvmspace, 323 ("oldvmspace still used")); 324 vmspace_free(oldvmspace); 325 td->td_pflags &= ~TDP_EXECVMSPC; 326 } 327 } 328 329 /* 330 * XXX: kern_execve has the astonishing property of not always returning to 331 * the caller. If sufficiently bad things happen during the call to 332 * do_execve(), it can end up calling exit1(); as a result, callers must 333 * avoid doing anything which they might need to undo (e.g., allocating 334 * memory). 335 */ 336 int 337 kern_execve(struct thread *td, struct image_args *args, struct mac *mac_p) 338 { 339 340 AUDIT_ARG_ARGV(args->begin_argv, args->argc, 341 args->begin_envv - args->begin_argv); 342 AUDIT_ARG_ENVV(args->begin_envv, args->envc, 343 args->endp - args->begin_envv); 344 return (do_execve(td, args, mac_p)); 345 } 346 347 /* 348 * In-kernel implementation of execve(). All arguments are assumed to be 349 * userspace pointers from the passed thread. 350 */ 351 static int 352 do_execve(td, args, mac_p) 353 struct thread *td; 354 struct image_args *args; 355 struct mac *mac_p; 356 { 357 struct proc *p = td->td_proc; 358 struct nameidata nd; 359 struct ucred *oldcred; 360 struct uidinfo *euip = NULL; 361 register_t *stack_base; 362 int error, i; 363 struct image_params image_params, *imgp; 364 struct vattr attr; 365 int (*img_first)(struct image_params *); 366 struct pargs *oldargs = NULL, *newargs = NULL; 367 struct sigacts *oldsigacts = NULL, *newsigacts = NULL; 368 #ifdef KTRACE 369 struct vnode *tracevp = NULL; 370 struct ucred *tracecred = NULL; 371 #endif 372 struct vnode *oldtextvp = NULL, *newtextvp; 373 cap_rights_t rights; 374 int credential_changing; 375 int textset; 376 #ifdef MAC 377 struct label *interpvplabel = NULL; 378 int will_transition; 379 #endif 380 #ifdef HWPMC_HOOKS 381 struct pmckern_procexec pe; 382 #endif 383 static const char fexecv_proc_title[] = "(fexecv)"; 384 385 imgp = &image_params; 386 387 /* 388 * Lock the process and set the P_INEXEC flag to indicate that 389 * it should be left alone until we're done here. This is 390 * necessary to avoid race conditions - e.g. in ptrace() - 391 * that might allow a local user to illicitly obtain elevated 392 * privileges. 393 */ 394 PROC_LOCK(p); 395 KASSERT((p->p_flag & P_INEXEC) == 0, 396 ("%s(): process already has P_INEXEC flag", __func__)); 397 p->p_flag |= P_INEXEC; 398 PROC_UNLOCK(p); 399 400 /* 401 * Initialize part of the common data 402 */ 403 bzero(imgp, sizeof(*imgp)); 404 imgp->proc = p; 405 imgp->attr = &attr; 406 imgp->args = args; 407 oldcred = p->p_ucred; 408 409 #ifdef MAC 410 error = mac_execve_enter(imgp, mac_p); 411 if (error) 412 goto exec_fail; 413 #endif 414 415 /* 416 * Translate the file name. namei() returns a vnode pointer 417 * in ni_vp among other things. 418 * 419 * XXXAUDIT: It would be desirable to also audit the name of the 420 * interpreter if this is an interpreted binary. 421 */ 422 if (args->fname != NULL) { 423 NDINIT(&nd, LOOKUP, ISOPEN | LOCKLEAF | FOLLOW | SAVENAME 424 | AUDITVNODE1, UIO_SYSSPACE, args->fname, td); 425 } 426 427 SDT_PROBE1(proc, , , exec, args->fname); 428 429 interpret: 430 if (args->fname != NULL) { 431 #ifdef CAPABILITY_MODE 432 /* 433 * While capability mode can't reach this point via direct 434 * path arguments to execve(), we also don't allow 435 * interpreters to be used in capability mode (for now). 436 * Catch indirect lookups and return a permissions error. 437 */ 438 if (IN_CAPABILITY_MODE(td)) { 439 error = ECAPMODE; 440 goto exec_fail; 441 } 442 #endif 443 error = namei(&nd); 444 if (error) 445 goto exec_fail; 446 447 newtextvp = nd.ni_vp; 448 imgp->vp = newtextvp; 449 } else { 450 AUDIT_ARG_FD(args->fd); 451 /* 452 * Descriptors opened only with O_EXEC or O_RDONLY are allowed. 453 */ 454 error = fgetvp_exec(td, args->fd, 455 cap_rights_init(&rights, CAP_FEXECVE), &newtextvp); 456 if (error) 457 goto exec_fail; 458 vn_lock(newtextvp, LK_EXCLUSIVE | LK_RETRY); 459 AUDIT_ARG_VNODE1(newtextvp); 460 imgp->vp = newtextvp; 461 } 462 463 /* 464 * Check file permissions (also 'opens' file) 465 */ 466 error = exec_check_permissions(imgp); 467 if (error) 468 goto exec_fail_dealloc; 469 470 imgp->object = imgp->vp->v_object; 471 if (imgp->object != NULL) 472 vm_object_reference(imgp->object); 473 474 /* 475 * Set VV_TEXT now so no one can write to the executable while we're 476 * activating it. 477 * 478 * Remember if this was set before and unset it in case this is not 479 * actually an executable image. 480 */ 481 textset = VOP_IS_TEXT(imgp->vp); 482 VOP_SET_TEXT(imgp->vp); 483 484 error = exec_map_first_page(imgp); 485 if (error) 486 goto exec_fail_dealloc; 487 488 imgp->proc->p_osrel = 0; 489 490 /* 491 * Implement image setuid/setgid. 492 * 493 * Determine new credentials before attempting image activators 494 * so that it can be used by process_exec handlers to determine 495 * credential/setid changes. 496 * 497 * Don't honor setuid/setgid if the filesystem prohibits it or if 498 * the process is being traced. 499 * 500 * We disable setuid/setgid/etc in capability mode on the basis 501 * that most setugid applications are not written with that 502 * environment in mind, and will therefore almost certainly operate 503 * incorrectly. In principle there's no reason that setugid 504 * applications might not be useful in capability mode, so we may want 505 * to reconsider this conservative design choice in the future. 506 * 507 * XXXMAC: For the time being, use NOSUID to also prohibit 508 * transitions on the file system. 509 */ 510 credential_changing = 0; 511 credential_changing |= (attr.va_mode & S_ISUID) && 512 oldcred->cr_uid != attr.va_uid; 513 credential_changing |= (attr.va_mode & S_ISGID) && 514 oldcred->cr_gid != attr.va_gid; 515 #ifdef MAC 516 will_transition = mac_vnode_execve_will_transition(oldcred, imgp->vp, 517 interpvplabel, imgp); 518 credential_changing |= will_transition; 519 #endif 520 521 if (credential_changing && 522 #ifdef CAPABILITY_MODE 523 ((oldcred->cr_flags & CRED_FLAG_CAPMODE) == 0) && 524 #endif 525 (imgp->vp->v_mount->mnt_flag & MNT_NOSUID) == 0 && 526 (p->p_flag & P_TRACED) == 0) { 527 imgp->credential_setid = true; 528 VOP_UNLOCK(imgp->vp, 0); 529 imgp->newcred = crdup(oldcred); 530 if (attr.va_mode & S_ISUID) { 531 euip = uifind(attr.va_uid); 532 change_euid(imgp->newcred, euip); 533 } 534 vn_lock(imgp->vp, LK_EXCLUSIVE | LK_RETRY); 535 if (attr.va_mode & S_ISGID) 536 change_egid(imgp->newcred, attr.va_gid); 537 /* 538 * Implement correct POSIX saved-id behavior. 539 * 540 * XXXMAC: Note that the current logic will save the 541 * uid and gid if a MAC domain transition occurs, even 542 * though maybe it shouldn't. 543 */ 544 change_svuid(imgp->newcred, imgp->newcred->cr_uid); 545 change_svgid(imgp->newcred, imgp->newcred->cr_gid); 546 } else { 547 /* 548 * Implement correct POSIX saved-id behavior. 549 * 550 * XXX: It's not clear that the existing behavior is 551 * POSIX-compliant. A number of sources indicate that the 552 * saved uid/gid should only be updated if the new ruid is 553 * not equal to the old ruid, or the new euid is not equal 554 * to the old euid and the new euid is not equal to the old 555 * ruid. The FreeBSD code always updates the saved uid/gid. 556 * Also, this code uses the new (replaced) euid and egid as 557 * the source, which may or may not be the right ones to use. 558 */ 559 if (oldcred->cr_svuid != oldcred->cr_uid || 560 oldcred->cr_svgid != oldcred->cr_gid) { 561 VOP_UNLOCK(imgp->vp, 0); 562 imgp->newcred = crdup(oldcred); 563 vn_lock(imgp->vp, LK_EXCLUSIVE | LK_RETRY); 564 change_svuid(imgp->newcred, imgp->newcred->cr_uid); 565 change_svgid(imgp->newcred, imgp->newcred->cr_gid); 566 } 567 } 568 /* The new credentials are installed into the process later. */ 569 570 /* 571 * Do the best to calculate the full path to the image file. 572 */ 573 if (args->fname != NULL && args->fname[0] == '/') 574 imgp->execpath = args->fname; 575 else { 576 VOP_UNLOCK(imgp->vp, 0); 577 if (vn_fullpath(td, imgp->vp, &imgp->execpath, 578 &imgp->freepath) != 0) 579 imgp->execpath = args->fname; 580 vn_lock(imgp->vp, LK_EXCLUSIVE | LK_RETRY); 581 } 582 583 /* 584 * If the current process has a special image activator it 585 * wants to try first, call it. For example, emulating shell 586 * scripts differently. 587 */ 588 error = -1; 589 if ((img_first = imgp->proc->p_sysent->sv_imgact_try) != NULL) 590 error = img_first(imgp); 591 592 /* 593 * Loop through the list of image activators, calling each one. 594 * An activator returns -1 if there is no match, 0 on success, 595 * and an error otherwise. 596 */ 597 for (i = 0; error == -1 && execsw[i]; ++i) { 598 if (execsw[i]->ex_imgact == NULL || 599 execsw[i]->ex_imgact == img_first) { 600 continue; 601 } 602 error = (*execsw[i]->ex_imgact)(imgp); 603 } 604 605 if (error) { 606 if (error == -1) { 607 if (textset == 0) 608 VOP_UNSET_TEXT(imgp->vp); 609 error = ENOEXEC; 610 } 611 goto exec_fail_dealloc; 612 } 613 614 /* 615 * Special interpreter operation, cleanup and loop up to try to 616 * activate the interpreter. 617 */ 618 if (imgp->interpreted) { 619 exec_unmap_first_page(imgp); 620 /* 621 * VV_TEXT needs to be unset for scripts. There is a short 622 * period before we determine that something is a script where 623 * VV_TEXT will be set. The vnode lock is held over this 624 * entire period so nothing should illegitimately be blocked. 625 */ 626 VOP_UNSET_TEXT(imgp->vp); 627 /* free name buffer and old vnode */ 628 if (args->fname != NULL) 629 NDFREE(&nd, NDF_ONLY_PNBUF); 630 #ifdef MAC 631 mac_execve_interpreter_enter(newtextvp, &interpvplabel); 632 #endif 633 if (imgp->opened) { 634 VOP_CLOSE(newtextvp, FREAD, td->td_ucred, td); 635 imgp->opened = 0; 636 } 637 vput(newtextvp); 638 vm_object_deallocate(imgp->object); 639 imgp->object = NULL; 640 imgp->credential_setid = false; 641 if (imgp->newcred != NULL) { 642 crfree(imgp->newcred); 643 imgp->newcred = NULL; 644 } 645 imgp->execpath = NULL; 646 free(imgp->freepath, M_TEMP); 647 imgp->freepath = NULL; 648 /* set new name to that of the interpreter */ 649 NDINIT(&nd, LOOKUP, LOCKLEAF | FOLLOW | SAVENAME, 650 UIO_SYSSPACE, imgp->interpreter_name, td); 651 args->fname = imgp->interpreter_name; 652 goto interpret; 653 } 654 655 /* 656 * NB: We unlock the vnode here because it is believed that none 657 * of the sv_copyout_strings/sv_fixup operations require the vnode. 658 */ 659 VOP_UNLOCK(imgp->vp, 0); 660 661 if (disallow_high_osrel && 662 P_OSREL_MAJOR(p->p_osrel) > P_OSREL_MAJOR(__FreeBSD_version)) { 663 error = ENOEXEC; 664 uprintf("Osrel %d for image %s too high\n", p->p_osrel, 665 imgp->execpath != NULL ? imgp->execpath : "<unresolved>"); 666 vn_lock(imgp->vp, LK_SHARED | LK_RETRY); 667 goto exec_fail_dealloc; 668 } 669 670 /* ABI enforces the use of Capsicum. Switch into capabilities mode. */ 671 if (SV_PROC_FLAG(p, SV_CAPSICUM)) 672 sys_cap_enter(td, NULL); 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 if (args->fdp != NULL) { 693 /* Install a brand new file descriptor table. */ 694 fdinstall_remapped(td, args->fdp); 695 args->fdp = NULL; 696 } else { 697 /* 698 * Keep on using the existing file descriptor table. For 699 * security and other reasons, the file descriptor table 700 * cannot be shared after an exec. 701 */ 702 fdunshare(td); 703 /* close files on exec */ 704 fdcloseexec(td); 705 } 706 707 /* 708 * Malloc things before we need locks. 709 */ 710 i = imgp->args->begin_envv - imgp->args->begin_argv; 711 /* Cache arguments if they fit inside our allowance */ 712 if (ps_arg_cache_limit >= i + sizeof(struct pargs)) { 713 newargs = pargs_alloc(i); 714 bcopy(imgp->args->begin_argv, newargs->ar_args, i); 715 } 716 717 /* 718 * For security and other reasons, signal handlers cannot 719 * be shared after an exec. The new process gets a copy of the old 720 * handlers. In execsigs(), the new process will have its signals 721 * reset. 722 */ 723 if (sigacts_shared(p->p_sigacts)) { 724 oldsigacts = p->p_sigacts; 725 newsigacts = sigacts_alloc(); 726 sigacts_copy(newsigacts, oldsigacts); 727 } 728 729 vn_lock(imgp->vp, LK_SHARED | LK_RETRY); 730 731 PROC_LOCK(p); 732 if (oldsigacts) 733 p->p_sigacts = newsigacts; 734 /* Stop profiling */ 735 stopprofclock(p); 736 737 /* reset caught signals */ 738 execsigs(p); 739 740 /* name this process - nameiexec(p, ndp) */ 741 bzero(p->p_comm, sizeof(p->p_comm)); 742 if (args->fname) 743 bcopy(nd.ni_cnd.cn_nameptr, p->p_comm, 744 min(nd.ni_cnd.cn_namelen, MAXCOMLEN)); 745 else if (vn_commname(newtextvp, p->p_comm, sizeof(p->p_comm)) != 0) 746 bcopy(fexecv_proc_title, p->p_comm, sizeof(fexecv_proc_title)); 747 bcopy(p->p_comm, td->td_name, sizeof(td->td_name)); 748 #ifdef KTR 749 sched_clear_tdname(td); 750 #endif 751 752 /* 753 * mark as execed, wakeup the process that vforked (if any) and tell 754 * it that it now has its own resources back 755 */ 756 p->p_flag |= P_EXEC; 757 if ((p->p_flag2 & P2_NOTRACE_EXEC) == 0) 758 p->p_flag2 &= ~P2_NOTRACE; 759 if (p->p_flag & P_PPWAIT) { 760 p->p_flag &= ~(P_PPWAIT | P_PPTRACE); 761 cv_broadcast(&p->p_pwait); 762 } 763 764 /* 765 * Implement image setuid/setgid installation. 766 */ 767 if (imgp->credential_setid) { 768 /* 769 * Turn off syscall tracing for set-id programs, except for 770 * root. Record any set-id flags first to make sure that 771 * we do not regain any tracing during a possible block. 772 */ 773 setsugid(p); 774 775 #ifdef KTRACE 776 if (p->p_tracecred != NULL && 777 priv_check_cred(p->p_tracecred, PRIV_DEBUG_DIFFCRED, 0)) 778 ktrprocexec(p, &tracecred, &tracevp); 779 #endif 780 /* 781 * Close any file descriptors 0..2 that reference procfs, 782 * then make sure file descriptors 0..2 are in use. 783 * 784 * Both fdsetugidsafety() and fdcheckstd() may call functions 785 * taking sleepable locks, so temporarily drop our locks. 786 */ 787 PROC_UNLOCK(p); 788 VOP_UNLOCK(imgp->vp, 0); 789 fdsetugidsafety(td); 790 error = fdcheckstd(td); 791 vn_lock(imgp->vp, LK_SHARED | LK_RETRY); 792 if (error != 0) 793 goto exec_fail_dealloc; 794 PROC_LOCK(p); 795 #ifdef MAC 796 if (will_transition) { 797 mac_vnode_execve_transition(oldcred, imgp->newcred, 798 imgp->vp, interpvplabel, imgp); 799 } 800 #endif 801 } else { 802 if (oldcred->cr_uid == oldcred->cr_ruid && 803 oldcred->cr_gid == oldcred->cr_rgid) 804 p->p_flag &= ~P_SUGID; 805 } 806 /* 807 * Set the new credentials. 808 */ 809 if (imgp->newcred != NULL) { 810 proc_set_cred(p, imgp->newcred); 811 crfree(oldcred); 812 oldcred = NULL; 813 } 814 815 /* 816 * Store the vp for use in procfs. This vnode was referenced by namei 817 * or fgetvp_exec. 818 */ 819 oldtextvp = p->p_textvp; 820 p->p_textvp = newtextvp; 821 822 #ifdef KDTRACE_HOOKS 823 /* 824 * Tell the DTrace fasttrap provider about the exec if it 825 * has declared an interest. 826 */ 827 if (dtrace_fasttrap_exec) 828 dtrace_fasttrap_exec(p); 829 #endif 830 831 /* 832 * Notify others that we exec'd, and clear the P_INEXEC flag 833 * as we're now a bona fide freshly-execed process. 834 */ 835 KNOTE_LOCKED(&p->p_klist, NOTE_EXEC); 836 p->p_flag &= ~P_INEXEC; 837 838 /* clear "fork but no exec" flag, as we _are_ execing */ 839 p->p_acflag &= ~AFORK; 840 841 /* 842 * Free any previous argument cache and replace it with 843 * the new argument cache, if any. 844 */ 845 oldargs = p->p_args; 846 p->p_args = newargs; 847 newargs = NULL; 848 849 #ifdef HWPMC_HOOKS 850 /* 851 * Check if system-wide sampling is in effect or if the 852 * current process is using PMCs. If so, do exec() time 853 * processing. This processing needs to happen AFTER the 854 * P_INEXEC flag is cleared. 855 * 856 * The proc lock needs to be released before taking the PMC 857 * SX. 858 */ 859 if (PMC_SYSTEM_SAMPLING_ACTIVE() || PMC_PROC_IS_USING_PMCS(p)) { 860 PROC_UNLOCK(p); 861 VOP_UNLOCK(imgp->vp, 0); 862 pe.pm_credentialschanged = credential_changing; 863 pe.pm_entryaddr = imgp->entry_addr; 864 865 PMC_CALL_HOOK_X(td, PMC_FN_PROCESS_EXEC, (void *) &pe); 866 vn_lock(imgp->vp, LK_SHARED | LK_RETRY); 867 } else 868 PROC_UNLOCK(p); 869 #else /* !HWPMC_HOOKS */ 870 PROC_UNLOCK(p); 871 #endif 872 873 /* Set values passed into the program in registers. */ 874 if (p->p_sysent->sv_setregs) 875 (*p->p_sysent->sv_setregs)(td, imgp, 876 (u_long)(uintptr_t)stack_base); 877 else 878 exec_setregs(td, imgp, (u_long)(uintptr_t)stack_base); 879 880 vfs_mark_atime(imgp->vp, td->td_ucred); 881 882 SDT_PROBE1(proc, , , exec__success, args->fname); 883 884 exec_fail_dealloc: 885 if (imgp->firstpage != NULL) 886 exec_unmap_first_page(imgp); 887 888 if (imgp->vp != NULL) { 889 if (args->fname) 890 NDFREE(&nd, NDF_ONLY_PNBUF); 891 if (imgp->opened) 892 VOP_CLOSE(imgp->vp, FREAD, td->td_ucred, td); 893 if (error != 0) 894 vput(imgp->vp); 895 else 896 VOP_UNLOCK(imgp->vp, 0); 897 } 898 899 if (imgp->object != NULL) 900 vm_object_deallocate(imgp->object); 901 902 free(imgp->freepath, M_TEMP); 903 904 if (error == 0) { 905 PROC_LOCK(p); 906 td->td_dbgflags |= TDB_EXEC; 907 PROC_UNLOCK(p); 908 909 /* 910 * Stop the process here if its stop event mask has 911 * the S_EXEC bit set. 912 */ 913 STOPEVENT(p, S_EXEC, 0); 914 } else { 915 exec_fail: 916 /* we're done here, clear P_INEXEC */ 917 PROC_LOCK(p); 918 p->p_flag &= ~P_INEXEC; 919 PROC_UNLOCK(p); 920 921 SDT_PROBE1(proc, , , exec__failure, error); 922 } 923 924 if (imgp->newcred != NULL && oldcred != NULL) 925 crfree(imgp->newcred); 926 927 #ifdef MAC 928 mac_execve_exit(imgp); 929 mac_execve_interpreter_exit(interpvplabel); 930 #endif 931 exec_free_args(args); 932 933 /* 934 * Handle deferred decrement of ref counts. 935 */ 936 if (oldtextvp != NULL) 937 vrele(oldtextvp); 938 #ifdef KTRACE 939 if (tracevp != NULL) 940 vrele(tracevp); 941 if (tracecred != NULL) 942 crfree(tracecred); 943 #endif 944 pargs_drop(oldargs); 945 pargs_drop(newargs); 946 if (oldsigacts != NULL) 947 sigacts_free(oldsigacts); 948 if (euip != NULL) 949 uifree(euip); 950 951 if (error && imgp->vmspace_destroyed) { 952 /* sorry, no more process anymore. exit gracefully */ 953 exit1(td, 0, SIGABRT); 954 /* NOT REACHED */ 955 } 956 957 #ifdef KTRACE 958 if (error == 0) 959 ktrprocctor(p); 960 #endif 961 962 return (error); 963 } 964 965 int 966 exec_map_first_page(imgp) 967 struct image_params *imgp; 968 { 969 int rv, i, after, initial_pagein; 970 vm_page_t ma[VM_INITIAL_PAGEIN]; 971 vm_object_t object; 972 973 if (imgp->firstpage != NULL) 974 exec_unmap_first_page(imgp); 975 976 object = imgp->vp->v_object; 977 if (object == NULL) 978 return (EACCES); 979 VM_OBJECT_WLOCK(object); 980 #if VM_NRESERVLEVEL > 0 981 vm_object_color(object, 0); 982 #endif 983 ma[0] = vm_page_grab(object, 0, VM_ALLOC_NORMAL); 984 if (ma[0]->valid != VM_PAGE_BITS_ALL) { 985 if (!vm_pager_has_page(object, 0, NULL, &after)) { 986 vm_page_lock(ma[0]); 987 vm_page_free(ma[0]); 988 vm_page_unlock(ma[0]); 989 vm_page_xunbusy(ma[0]); 990 VM_OBJECT_WUNLOCK(object); 991 return (EIO); 992 } 993 initial_pagein = min(after, VM_INITIAL_PAGEIN); 994 KASSERT(initial_pagein <= object->size, 995 ("%s: initial_pagein %d object->size %ju", 996 __func__, initial_pagein, (uintmax_t )object->size)); 997 for (i = 1; i < initial_pagein; i++) { 998 if ((ma[i] = vm_page_next(ma[i - 1])) != NULL) { 999 if (ma[i]->valid) 1000 break; 1001 if (vm_page_tryxbusy(ma[i])) 1002 break; 1003 } else { 1004 ma[i] = vm_page_alloc(object, i, 1005 VM_ALLOC_NORMAL | VM_ALLOC_IFNOTCACHED); 1006 if (ma[i] == NULL) 1007 break; 1008 } 1009 } 1010 initial_pagein = i; 1011 rv = vm_pager_get_pages(object, ma, initial_pagein, NULL, NULL); 1012 if (rv != VM_PAGER_OK) { 1013 for (i = 0; i < initial_pagein; i++) { 1014 vm_page_lock(ma[i]); 1015 vm_page_free(ma[i]); 1016 vm_page_unlock(ma[i]); 1017 vm_page_xunbusy(ma[i]); 1018 } 1019 VM_OBJECT_WUNLOCK(object); 1020 return (EIO); 1021 } 1022 for (i = 1; i < initial_pagein; i++) 1023 vm_page_readahead_finish(ma[i]); 1024 } 1025 vm_page_xunbusy(ma[0]); 1026 vm_page_lock(ma[0]); 1027 vm_page_hold(ma[0]); 1028 vm_page_activate(ma[0]); 1029 vm_page_unlock(ma[0]); 1030 VM_OBJECT_WUNLOCK(object); 1031 1032 imgp->firstpage = sf_buf_alloc(ma[0], 0); 1033 imgp->image_header = (char *)sf_buf_kva(imgp->firstpage); 1034 1035 return (0); 1036 } 1037 1038 void 1039 exec_unmap_first_page(imgp) 1040 struct image_params *imgp; 1041 { 1042 vm_page_t m; 1043 1044 if (imgp->firstpage != NULL) { 1045 m = sf_buf_page(imgp->firstpage); 1046 sf_buf_free(imgp->firstpage); 1047 imgp->firstpage = NULL; 1048 vm_page_lock(m); 1049 vm_page_unhold(m); 1050 vm_page_unlock(m); 1051 } 1052 } 1053 1054 /* 1055 * Destroy old address space, and allocate a new stack 1056 * The new stack is only SGROWSIZ large because it is grown 1057 * automatically in trap.c. 1058 */ 1059 int 1060 exec_new_vmspace(imgp, sv) 1061 struct image_params *imgp; 1062 struct sysentvec *sv; 1063 { 1064 int error; 1065 struct proc *p = imgp->proc; 1066 struct vmspace *vmspace = p->p_vmspace; 1067 vm_object_t obj; 1068 struct rlimit rlim_stack; 1069 vm_offset_t sv_minuser, stack_addr; 1070 vm_map_t map; 1071 u_long ssiz; 1072 1073 imgp->vmspace_destroyed = 1; 1074 imgp->sysent = sv; 1075 1076 /* May be called with Giant held */ 1077 EVENTHANDLER_INVOKE(process_exec, p, imgp); 1078 1079 /* 1080 * Blow away entire process VM, if address space not shared, 1081 * otherwise, create a new VM space so that other threads are 1082 * not disrupted 1083 */ 1084 map = &vmspace->vm_map; 1085 if (map_at_zero) 1086 sv_minuser = sv->sv_minuser; 1087 else 1088 sv_minuser = MAX(sv->sv_minuser, PAGE_SIZE); 1089 if (vmspace->vm_refcnt == 1 && vm_map_min(map) == sv_minuser && 1090 vm_map_max(map) == sv->sv_maxuser) { 1091 shmexit(vmspace); 1092 pmap_remove_pages(vmspace_pmap(vmspace)); 1093 vm_map_remove(map, vm_map_min(map), vm_map_max(map)); 1094 } else { 1095 error = vmspace_exec(p, sv_minuser, sv->sv_maxuser); 1096 if (error) 1097 return (error); 1098 vmspace = p->p_vmspace; 1099 map = &vmspace->vm_map; 1100 } 1101 1102 /* Map a shared page */ 1103 obj = sv->sv_shared_page_obj; 1104 if (obj != NULL) { 1105 vm_object_reference(obj); 1106 error = vm_map_fixed(map, obj, 0, 1107 sv->sv_shared_page_base, sv->sv_shared_page_len, 1108 VM_PROT_READ | VM_PROT_EXECUTE, 1109 VM_PROT_READ | VM_PROT_EXECUTE, 1110 MAP_INHERIT_SHARE | MAP_ACC_NO_CHARGE); 1111 if (error) { 1112 vm_object_deallocate(obj); 1113 return (error); 1114 } 1115 } 1116 1117 /* Allocate a new stack */ 1118 if (imgp->stack_sz != 0) { 1119 ssiz = trunc_page(imgp->stack_sz); 1120 PROC_LOCK(p); 1121 lim_rlimit_proc(p, RLIMIT_STACK, &rlim_stack); 1122 PROC_UNLOCK(p); 1123 if (ssiz > rlim_stack.rlim_max) 1124 ssiz = rlim_stack.rlim_max; 1125 if (ssiz > rlim_stack.rlim_cur) { 1126 rlim_stack.rlim_cur = ssiz; 1127 kern_setrlimit(curthread, RLIMIT_STACK, &rlim_stack); 1128 } 1129 } else if (sv->sv_maxssiz != NULL) { 1130 ssiz = *sv->sv_maxssiz; 1131 } else { 1132 ssiz = maxssiz; 1133 } 1134 stack_addr = sv->sv_usrstack - ssiz; 1135 error = vm_map_stack(map, stack_addr, (vm_size_t)ssiz, 1136 obj != NULL && imgp->stack_prot != 0 ? imgp->stack_prot : 1137 sv->sv_stackprot, 1138 VM_PROT_ALL, MAP_STACK_GROWS_DOWN); 1139 if (error) 1140 return (error); 1141 1142 /* 1143 * vm_ssize and vm_maxsaddr are somewhat antiquated concepts, but they 1144 * are still used to enforce the stack rlimit on the process stack. 1145 */ 1146 vmspace->vm_ssize = sgrowsiz >> PAGE_SHIFT; 1147 vmspace->vm_maxsaddr = (char *)stack_addr; 1148 1149 return (0); 1150 } 1151 1152 /* 1153 * Copy out argument and environment strings from the old process address 1154 * space into the temporary string buffer. 1155 */ 1156 int 1157 exec_copyin_args(struct image_args *args, char *fname, 1158 enum uio_seg segflg, char **argv, char **envv) 1159 { 1160 u_long argp, envp; 1161 int error; 1162 size_t length; 1163 1164 bzero(args, sizeof(*args)); 1165 if (argv == NULL) 1166 return (EFAULT); 1167 1168 /* 1169 * Allocate demand-paged memory for the file name, argument, and 1170 * environment strings. 1171 */ 1172 error = exec_alloc_args(args); 1173 if (error != 0) 1174 return (error); 1175 1176 /* 1177 * Copy the file name. 1178 */ 1179 if (fname != NULL) { 1180 args->fname = args->buf; 1181 error = (segflg == UIO_SYSSPACE) ? 1182 copystr(fname, args->fname, PATH_MAX, &length) : 1183 copyinstr(fname, args->fname, PATH_MAX, &length); 1184 if (error != 0) 1185 goto err_exit; 1186 } else 1187 length = 0; 1188 1189 args->begin_argv = args->buf + length; 1190 args->endp = args->begin_argv; 1191 args->stringspace = ARG_MAX; 1192 1193 /* 1194 * extract arguments first 1195 */ 1196 for (;;) { 1197 error = fueword(argv++, &argp); 1198 if (error == -1) { 1199 error = EFAULT; 1200 goto err_exit; 1201 } 1202 if (argp == 0) 1203 break; 1204 error = copyinstr((void *)(uintptr_t)argp, args->endp, 1205 args->stringspace, &length); 1206 if (error != 0) { 1207 if (error == ENAMETOOLONG) 1208 error = E2BIG; 1209 goto err_exit; 1210 } 1211 args->stringspace -= length; 1212 args->endp += length; 1213 args->argc++; 1214 } 1215 1216 args->begin_envv = args->endp; 1217 1218 /* 1219 * extract environment strings 1220 */ 1221 if (envv) { 1222 for (;;) { 1223 error = fueword(envv++, &envp); 1224 if (error == -1) { 1225 error = EFAULT; 1226 goto err_exit; 1227 } 1228 if (envp == 0) 1229 break; 1230 error = copyinstr((void *)(uintptr_t)envp, 1231 args->endp, args->stringspace, &length); 1232 if (error != 0) { 1233 if (error == ENAMETOOLONG) 1234 error = E2BIG; 1235 goto err_exit; 1236 } 1237 args->stringspace -= length; 1238 args->endp += length; 1239 args->envc++; 1240 } 1241 } 1242 1243 return (0); 1244 1245 err_exit: 1246 exec_free_args(args); 1247 return (error); 1248 } 1249 1250 int 1251 exec_copyin_data_fds(struct thread *td, struct image_args *args, 1252 const void *data, size_t datalen, const int *fds, size_t fdslen) 1253 { 1254 struct filedesc *ofdp; 1255 const char *p; 1256 int *kfds; 1257 int error; 1258 1259 memset(args, '\0', sizeof(*args)); 1260 ofdp = td->td_proc->p_fd; 1261 if (datalen >= ARG_MAX || fdslen > ofdp->fd_lastfile + 1) 1262 return (E2BIG); 1263 error = exec_alloc_args(args); 1264 if (error != 0) 1265 return (error); 1266 1267 args->begin_argv = args->buf; 1268 args->stringspace = ARG_MAX; 1269 1270 if (datalen > 0) { 1271 /* 1272 * Argument buffer has been provided. Copy it into the 1273 * kernel as a single string and add a terminating null 1274 * byte. 1275 */ 1276 error = copyin(data, args->begin_argv, datalen); 1277 if (error != 0) 1278 goto err_exit; 1279 args->begin_argv[datalen] = '\0'; 1280 args->endp = args->begin_argv + datalen + 1; 1281 args->stringspace -= datalen + 1; 1282 1283 /* 1284 * Traditional argument counting. Count the number of 1285 * null bytes. 1286 */ 1287 for (p = args->begin_argv; p < args->endp; ++p) 1288 if (*p == '\0') 1289 ++args->argc; 1290 } else { 1291 /* No argument buffer provided. */ 1292 args->endp = args->begin_argv; 1293 } 1294 /* There are no environment variables. */ 1295 args->begin_envv = args->endp; 1296 1297 /* Create new file descriptor table. */ 1298 kfds = malloc(fdslen * sizeof(int), M_TEMP, M_WAITOK); 1299 error = copyin(fds, kfds, fdslen * sizeof(int)); 1300 if (error != 0) { 1301 free(kfds, M_TEMP); 1302 goto err_exit; 1303 } 1304 error = fdcopy_remapped(ofdp, kfds, fdslen, &args->fdp); 1305 free(kfds, M_TEMP); 1306 if (error != 0) 1307 goto err_exit; 1308 1309 return (0); 1310 err_exit: 1311 exec_free_args(args); 1312 return (error); 1313 } 1314 1315 /* 1316 * Allocate temporary demand-paged, zero-filled memory for the file name, 1317 * argument, and environment strings. Returns zero if the allocation succeeds 1318 * and ENOMEM otherwise. 1319 */ 1320 int 1321 exec_alloc_args(struct image_args *args) 1322 { 1323 1324 args->buf = (char *)kmap_alloc_wait(exec_map, PATH_MAX + ARG_MAX); 1325 return (args->buf != NULL ? 0 : ENOMEM); 1326 } 1327 1328 void 1329 exec_free_args(struct image_args *args) 1330 { 1331 1332 if (args->buf != NULL) { 1333 kmap_free_wakeup(exec_map, (vm_offset_t)args->buf, 1334 PATH_MAX + ARG_MAX); 1335 args->buf = NULL; 1336 } 1337 if (args->fname_buf != NULL) { 1338 free(args->fname_buf, M_TEMP); 1339 args->fname_buf = NULL; 1340 } 1341 if (args->fdp != NULL) 1342 fdescfree_remapped(args->fdp); 1343 } 1344 1345 /* 1346 * Copy strings out to the new process address space, constructing new arg 1347 * and env vector tables. Return a pointer to the base so that it can be used 1348 * as the initial stack pointer. 1349 */ 1350 register_t * 1351 exec_copyout_strings(imgp) 1352 struct image_params *imgp; 1353 { 1354 int argc, envc; 1355 char **vectp; 1356 char *stringp; 1357 uintptr_t destp; 1358 register_t *stack_base; 1359 struct ps_strings *arginfo; 1360 struct proc *p; 1361 size_t execpath_len; 1362 int szsigcode, szps; 1363 char canary[sizeof(long) * 8]; 1364 1365 szps = sizeof(pagesizes[0]) * MAXPAGESIZES; 1366 /* 1367 * Calculate string base and vector table pointers. 1368 * Also deal with signal trampoline code for this exec type. 1369 */ 1370 if (imgp->execpath != NULL && imgp->auxargs != NULL) 1371 execpath_len = strlen(imgp->execpath) + 1; 1372 else 1373 execpath_len = 0; 1374 p = imgp->proc; 1375 szsigcode = 0; 1376 arginfo = (struct ps_strings *)p->p_sysent->sv_psstrings; 1377 if (p->p_sysent->sv_sigcode_base == 0) { 1378 if (p->p_sysent->sv_szsigcode != NULL) 1379 szsigcode = *(p->p_sysent->sv_szsigcode); 1380 } 1381 destp = (uintptr_t)arginfo; 1382 1383 /* 1384 * install sigcode 1385 */ 1386 if (szsigcode != 0) { 1387 destp -= szsigcode; 1388 destp = rounddown2(destp, sizeof(void *)); 1389 copyout(p->p_sysent->sv_sigcode, (void *)destp, szsigcode); 1390 } 1391 1392 /* 1393 * Copy the image path for the rtld. 1394 */ 1395 if (execpath_len != 0) { 1396 destp -= execpath_len; 1397 imgp->execpathp = destp; 1398 copyout(imgp->execpath, (void *)destp, execpath_len); 1399 } 1400 1401 /* 1402 * Prepare the canary for SSP. 1403 */ 1404 arc4rand(canary, sizeof(canary), 0); 1405 destp -= sizeof(canary); 1406 imgp->canary = destp; 1407 copyout(canary, (void *)destp, sizeof(canary)); 1408 imgp->canarylen = sizeof(canary); 1409 1410 /* 1411 * Prepare the pagesizes array. 1412 */ 1413 destp -= szps; 1414 destp = rounddown2(destp, sizeof(void *)); 1415 imgp->pagesizes = destp; 1416 copyout(pagesizes, (void *)destp, szps); 1417 imgp->pagesizeslen = szps; 1418 1419 destp -= ARG_MAX - imgp->args->stringspace; 1420 destp = rounddown2(destp, sizeof(void *)); 1421 1422 /* 1423 * If we have a valid auxargs ptr, prepare some room 1424 * on the stack. 1425 */ 1426 if (imgp->auxargs) { 1427 /* 1428 * 'AT_COUNT*2' is size for the ELF Auxargs data. This is for 1429 * lower compatibility. 1430 */ 1431 imgp->auxarg_size = (imgp->auxarg_size) ? imgp->auxarg_size : 1432 (AT_COUNT * 2); 1433 /* 1434 * The '+ 2' is for the null pointers at the end of each of 1435 * the arg and env vector sets,and imgp->auxarg_size is room 1436 * for argument of Runtime loader. 1437 */ 1438 vectp = (char **)(destp - (imgp->args->argc + 1439 imgp->args->envc + 2 + imgp->auxarg_size) 1440 * sizeof(char *)); 1441 } else { 1442 /* 1443 * The '+ 2' is for the null pointers at the end of each of 1444 * the arg and env vector sets 1445 */ 1446 vectp = (char **)(destp - (imgp->args->argc + imgp->args->envc 1447 + 2) * sizeof(char *)); 1448 } 1449 1450 /* 1451 * vectp also becomes our initial stack base 1452 */ 1453 stack_base = (register_t *)vectp; 1454 1455 stringp = imgp->args->begin_argv; 1456 argc = imgp->args->argc; 1457 envc = imgp->args->envc; 1458 1459 /* 1460 * Copy out strings - arguments and environment. 1461 */ 1462 copyout(stringp, (void *)destp, ARG_MAX - imgp->args->stringspace); 1463 1464 /* 1465 * Fill in "ps_strings" struct for ps, w, etc. 1466 */ 1467 suword(&arginfo->ps_argvstr, (long)(intptr_t)vectp); 1468 suword32(&arginfo->ps_nargvstr, argc); 1469 1470 /* 1471 * Fill in argument portion of vector table. 1472 */ 1473 for (; argc > 0; --argc) { 1474 suword(vectp++, (long)(intptr_t)destp); 1475 while (*stringp++ != 0) 1476 destp++; 1477 destp++; 1478 } 1479 1480 /* a null vector table pointer separates the argp's from the envp's */ 1481 suword(vectp++, 0); 1482 1483 suword(&arginfo->ps_envstr, (long)(intptr_t)vectp); 1484 suword32(&arginfo->ps_nenvstr, envc); 1485 1486 /* 1487 * Fill in environment portion of vector table. 1488 */ 1489 for (; envc > 0; --envc) { 1490 suword(vectp++, (long)(intptr_t)destp); 1491 while (*stringp++ != 0) 1492 destp++; 1493 destp++; 1494 } 1495 1496 /* end of vector table is a null pointer */ 1497 suword(vectp, 0); 1498 1499 return (stack_base); 1500 } 1501 1502 /* 1503 * Check permissions of file to execute. 1504 * Called with imgp->vp locked. 1505 * Return 0 for success or error code on failure. 1506 */ 1507 int 1508 exec_check_permissions(imgp) 1509 struct image_params *imgp; 1510 { 1511 struct vnode *vp = imgp->vp; 1512 struct vattr *attr = imgp->attr; 1513 struct thread *td; 1514 int error, writecount; 1515 1516 td = curthread; 1517 1518 /* Get file attributes */ 1519 error = VOP_GETATTR(vp, attr, td->td_ucred); 1520 if (error) 1521 return (error); 1522 1523 #ifdef MAC 1524 error = mac_vnode_check_exec(td->td_ucred, imgp->vp, imgp); 1525 if (error) 1526 return (error); 1527 #endif 1528 1529 /* 1530 * 1) Check if file execution is disabled for the filesystem that 1531 * this file resides on. 1532 * 2) Ensure that at least one execute bit is on. Otherwise, a 1533 * privileged user will always succeed, and we don't want this 1534 * to happen unless the file really is executable. 1535 * 3) Ensure that the file is a regular file. 1536 */ 1537 if ((vp->v_mount->mnt_flag & MNT_NOEXEC) || 1538 (attr->va_mode & (S_IXUSR | S_IXGRP | S_IXOTH)) == 0 || 1539 (attr->va_type != VREG)) 1540 return (EACCES); 1541 1542 /* 1543 * Zero length files can't be exec'd 1544 */ 1545 if (attr->va_size == 0) 1546 return (ENOEXEC); 1547 1548 /* 1549 * Check for execute permission to file based on current credentials. 1550 */ 1551 error = VOP_ACCESS(vp, VEXEC, td->td_ucred, td); 1552 if (error) 1553 return (error); 1554 1555 /* 1556 * Check number of open-for-writes on the file and deny execution 1557 * if there are any. 1558 */ 1559 error = VOP_GET_WRITECOUNT(vp, &writecount); 1560 if (error != 0) 1561 return (error); 1562 if (writecount != 0) 1563 return (ETXTBSY); 1564 1565 /* 1566 * Call filesystem specific open routine (which does nothing in the 1567 * general case). 1568 */ 1569 error = VOP_OPEN(vp, FREAD, td->td_ucred, td, NULL); 1570 if (error == 0) 1571 imgp->opened = 1; 1572 return (error); 1573 } 1574 1575 /* 1576 * Exec handler registration 1577 */ 1578 int 1579 exec_register(execsw_arg) 1580 const struct execsw *execsw_arg; 1581 { 1582 const struct execsw **es, **xs, **newexecsw; 1583 int count = 2; /* New slot and trailing NULL */ 1584 1585 if (execsw) 1586 for (es = execsw; *es; es++) 1587 count++; 1588 newexecsw = malloc(count * sizeof(*es), M_TEMP, M_WAITOK); 1589 xs = newexecsw; 1590 if (execsw) 1591 for (es = execsw; *es; es++) 1592 *xs++ = *es; 1593 *xs++ = execsw_arg; 1594 *xs = NULL; 1595 if (execsw) 1596 free(execsw, M_TEMP); 1597 execsw = newexecsw; 1598 return (0); 1599 } 1600 1601 int 1602 exec_unregister(execsw_arg) 1603 const struct execsw *execsw_arg; 1604 { 1605 const struct execsw **es, **xs, **newexecsw; 1606 int count = 1; 1607 1608 if (execsw == NULL) 1609 panic("unregister with no handlers left?\n"); 1610 1611 for (es = execsw; *es; es++) { 1612 if (*es == execsw_arg) 1613 break; 1614 } 1615 if (*es == NULL) 1616 return (ENOENT); 1617 for (es = execsw; *es; es++) 1618 if (*es != execsw_arg) 1619 count++; 1620 newexecsw = malloc(count * sizeof(*es), M_TEMP, M_WAITOK); 1621 xs = newexecsw; 1622 for (es = execsw; *es; es++) 1623 if (*es != execsw_arg) 1624 *xs++ = *es; 1625 *xs = NULL; 1626 if (execsw) 1627 free(execsw, M_TEMP); 1628 execsw = newexecsw; 1629 return (0); 1630 } 1631