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_compat.h" 32 #include "opt_hwpmc_hooks.h" 33 #include "opt_ktrace.h" 34 #include "opt_vm.h" 35 36 #include <sys/param.h> 37 #include <sys/systm.h> 38 #include <sys/acct.h> 39 #include <sys/capsicum.h> 40 #include <sys/eventhandler.h> 41 #include <sys/exec.h> 42 #include <sys/fcntl.h> 43 #include <sys/filedesc.h> 44 #include <sys/imgact.h> 45 #include <sys/imgact_elf.h> 46 #include <sys/kernel.h> 47 #include <sys/lock.h> 48 #include <sys/malloc.h> 49 #include <sys/mman.h> 50 #include <sys/mount.h> 51 #include <sys/mutex.h> 52 #include <sys/namei.h> 53 #include <sys/pioctl.h> 54 #include <sys/priv.h> 55 #include <sys/proc.h> 56 #include <sys/ptrace.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/shm.h> 63 #include <sys/signalvar.h> 64 #include <sys/smp.h> 65 #include <sys/stat.h> 66 #include <sys/syscallsubr.h> 67 #include <sys/sysctl.h> 68 #include <sys/sysent.h> 69 #include <sys/sysproto.h> 70 #include <sys/vnode.h> 71 #include <sys/wait.h> 72 #ifdef KTRACE 73 #include <sys/ktrace.h> 74 #endif 75 76 #include <vm/vm.h> 77 #include <vm/vm_param.h> 78 #include <vm/pmap.h> 79 #include <vm/vm_page.h> 80 #include <vm/vm_map.h> 81 #include <vm/vm_kern.h> 82 #include <vm/vm_extern.h> 83 #include <vm/vm_object.h> 84 #include <vm/vm_pager.h> 85 86 #ifdef HWPMC_HOOKS 87 #include <sys/pmckern.h> 88 #endif 89 90 #include <machine/reg.h> 91 92 #include <security/audit/audit.h> 93 #include <security/mac/mac_framework.h> 94 95 #ifdef KDTRACE_HOOKS 96 #include <sys/dtrace_bsd.h> 97 dtrace_execexit_func_t dtrace_fasttrap_exec; 98 #endif 99 100 SDT_PROVIDER_DECLARE(proc); 101 SDT_PROBE_DEFINE1(proc, , , exec, "char *"); 102 SDT_PROBE_DEFINE1(proc, , , exec__failure, "int"); 103 SDT_PROBE_DEFINE1(proc, , , exec__success, "char *"); 104 105 MALLOC_DEFINE(M_PARGS, "proc-args", "Process arguments"); 106 107 int coredump_pack_fileinfo = 1; 108 SYSCTL_INT(_kern, OID_AUTO, coredump_pack_fileinfo, CTLFLAG_RWTUN, 109 &coredump_pack_fileinfo, 0, 110 "Enable file path packing in 'procstat -f' coredump notes"); 111 112 int coredump_pack_vmmapinfo = 1; 113 SYSCTL_INT(_kern, OID_AUTO, coredump_pack_vmmapinfo, CTLFLAG_RWTUN, 114 &coredump_pack_vmmapinfo, 0, 115 "Enable file path packing in 'procstat -v' coredump notes"); 116 117 static int sysctl_kern_ps_strings(SYSCTL_HANDLER_ARGS); 118 static int sysctl_kern_usrstack(SYSCTL_HANDLER_ARGS); 119 static int sysctl_kern_stackprot(SYSCTL_HANDLER_ARGS); 120 static int do_execve(struct thread *td, struct image_args *args, 121 struct mac *mac_p); 122 123 /* XXX This should be vm_size_t. */ 124 SYSCTL_PROC(_kern, KERN_PS_STRINGS, ps_strings, CTLTYPE_ULONG|CTLFLAG_RD| 125 CTLFLAG_MPSAFE, NULL, 0, sysctl_kern_ps_strings, "LU", ""); 126 127 /* XXX This should be vm_size_t. */ 128 SYSCTL_PROC(_kern, KERN_USRSTACK, usrstack, CTLTYPE_ULONG|CTLFLAG_RD| 129 CTLFLAG_CAPRD|CTLFLAG_MPSAFE, NULL, 0, sysctl_kern_usrstack, "LU", ""); 130 131 SYSCTL_PROC(_kern, OID_AUTO, stackprot, CTLTYPE_INT|CTLFLAG_RD|CTLFLAG_MPSAFE, 132 NULL, 0, sysctl_kern_stackprot, "I", ""); 133 134 u_long ps_arg_cache_limit = PAGE_SIZE / 16; 135 SYSCTL_ULONG(_kern, OID_AUTO, ps_arg_cache_limit, CTLFLAG_RW, 136 &ps_arg_cache_limit, 0, ""); 137 138 static int disallow_high_osrel; 139 SYSCTL_INT(_kern, OID_AUTO, disallow_high_osrel, CTLFLAG_RW, 140 &disallow_high_osrel, 0, 141 "Disallow execution of binaries built for higher version of the world"); 142 143 static int map_at_zero = 0; 144 SYSCTL_INT(_security_bsd, OID_AUTO, map_at_zero, CTLFLAG_RWTUN, &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 /* ABI enforces the use of Capsicum. Switch into capabilities mode. */ 675 if (SV_PROC_FLAG(p, SV_CAPSICUM)) 676 sys_cap_enter(td, NULL); 677 678 /* 679 * Copy out strings (args and env) and initialize stack base 680 */ 681 if (p->p_sysent->sv_copyout_strings) 682 stack_base = (*p->p_sysent->sv_copyout_strings)(imgp); 683 else 684 stack_base = exec_copyout_strings(imgp); 685 686 /* 687 * If custom stack fixup routine present for this process 688 * let it do the stack setup. 689 * Else stuff argument count as first item on stack 690 */ 691 if (p->p_sysent->sv_fixup != NULL) 692 (*p->p_sysent->sv_fixup)(&stack_base, imgp); 693 else 694 suword(--stack_base, imgp->args->argc); 695 696 if (args->fdp != NULL) { 697 /* Install a brand new file descriptor table. */ 698 fdinstall_remapped(td, args->fdp); 699 args->fdp = NULL; 700 } else { 701 /* 702 * Keep on using the existing file descriptor table. For 703 * security and other reasons, the file descriptor table 704 * cannot be shared after an exec. 705 */ 706 fdunshare(td); 707 /* close files on exec */ 708 fdcloseexec(td); 709 } 710 711 /* 712 * Malloc things before we need locks. 713 */ 714 i = imgp->args->begin_envv - imgp->args->begin_argv; 715 /* Cache arguments if they fit inside our allowance */ 716 if (ps_arg_cache_limit >= i + sizeof(struct pargs)) { 717 newargs = pargs_alloc(i); 718 bcopy(imgp->args->begin_argv, newargs->ar_args, i); 719 } 720 721 /* 722 * For security and other reasons, signal handlers cannot 723 * be shared after an exec. The new process gets a copy of the old 724 * handlers. In execsigs(), the new process will have its signals 725 * reset. 726 */ 727 if (sigacts_shared(p->p_sigacts)) { 728 oldsigacts = p->p_sigacts; 729 newsigacts = sigacts_alloc(); 730 sigacts_copy(newsigacts, oldsigacts); 731 } 732 733 vn_lock(imgp->vp, LK_SHARED | LK_RETRY); 734 735 PROC_LOCK(p); 736 if (oldsigacts) 737 p->p_sigacts = newsigacts; 738 /* Stop profiling */ 739 stopprofclock(p); 740 741 /* reset caught signals */ 742 execsigs(p); 743 744 /* name this process - nameiexec(p, ndp) */ 745 bzero(p->p_comm, sizeof(p->p_comm)); 746 if (args->fname) 747 bcopy(nd.ni_cnd.cn_nameptr, p->p_comm, 748 min(nd.ni_cnd.cn_namelen, MAXCOMLEN)); 749 else if (vn_commname(newtextvp, p->p_comm, sizeof(p->p_comm)) != 0) 750 bcopy(fexecv_proc_title, p->p_comm, sizeof(fexecv_proc_title)); 751 bcopy(p->p_comm, td->td_name, sizeof(td->td_name)); 752 #ifdef KTR 753 sched_clear_tdname(td); 754 #endif 755 756 /* 757 * mark as execed, wakeup the process that vforked (if any) and tell 758 * it that it now has its own resources back 759 */ 760 p->p_flag |= P_EXEC; 761 if ((p->p_flag2 & P2_NOTRACE_EXEC) == 0) 762 p->p_flag2 &= ~P2_NOTRACE; 763 if (p->p_flag & P_PPWAIT) { 764 p->p_flag &= ~(P_PPWAIT | P_PPTRACE); 765 cv_broadcast(&p->p_pwait); 766 /* STOPs are no longer ignored, arrange for AST */ 767 signotify(td); 768 } 769 770 /* 771 * Implement image setuid/setgid installation. 772 */ 773 if (imgp->credential_setid) { 774 /* 775 * Turn off syscall tracing for set-id programs, except for 776 * root. Record any set-id flags first to make sure that 777 * we do not regain any tracing during a possible block. 778 */ 779 setsugid(p); 780 781 #ifdef KTRACE 782 if (p->p_tracecred != NULL && 783 priv_check_cred(p->p_tracecred, PRIV_DEBUG_DIFFCRED, 0)) 784 ktrprocexec(p, &tracecred, &tracevp); 785 #endif 786 /* 787 * Close any file descriptors 0..2 that reference procfs, 788 * then make sure file descriptors 0..2 are in use. 789 * 790 * Both fdsetugidsafety() and fdcheckstd() may call functions 791 * taking sleepable locks, so temporarily drop our locks. 792 */ 793 PROC_UNLOCK(p); 794 VOP_UNLOCK(imgp->vp, 0); 795 fdsetugidsafety(td); 796 error = fdcheckstd(td); 797 vn_lock(imgp->vp, LK_SHARED | LK_RETRY); 798 if (error != 0) 799 goto exec_fail_dealloc; 800 PROC_LOCK(p); 801 #ifdef MAC 802 if (will_transition) { 803 mac_vnode_execve_transition(oldcred, imgp->newcred, 804 imgp->vp, interpvplabel, imgp); 805 } 806 #endif 807 } else { 808 if (oldcred->cr_uid == oldcred->cr_ruid && 809 oldcred->cr_gid == oldcred->cr_rgid) 810 p->p_flag &= ~P_SUGID; 811 } 812 /* 813 * Set the new credentials. 814 */ 815 if (imgp->newcred != NULL) { 816 proc_set_cred(p, imgp->newcred); 817 crfree(oldcred); 818 oldcred = NULL; 819 } 820 821 /* 822 * Store the vp for use in procfs. This vnode was referenced by namei 823 * or fgetvp_exec. 824 */ 825 oldtextvp = p->p_textvp; 826 p->p_textvp = newtextvp; 827 828 #ifdef KDTRACE_HOOKS 829 /* 830 * Tell the DTrace fasttrap provider about the exec if it 831 * has declared an interest. 832 */ 833 if (dtrace_fasttrap_exec) 834 dtrace_fasttrap_exec(p); 835 #endif 836 837 /* 838 * Notify others that we exec'd, and clear the P_INEXEC flag 839 * as we're now a bona fide freshly-execed process. 840 */ 841 KNOTE_LOCKED(p->p_klist, NOTE_EXEC); 842 p->p_flag &= ~P_INEXEC; 843 844 /* clear "fork but no exec" flag, as we _are_ execing */ 845 p->p_acflag &= ~AFORK; 846 847 /* 848 * Free any previous argument cache and replace it with 849 * the new argument cache, if any. 850 */ 851 oldargs = p->p_args; 852 p->p_args = newargs; 853 newargs = NULL; 854 855 #ifdef HWPMC_HOOKS 856 /* 857 * Check if system-wide sampling is in effect or if the 858 * current process is using PMCs. If so, do exec() time 859 * processing. This processing needs to happen AFTER the 860 * P_INEXEC flag is cleared. 861 * 862 * The proc lock needs to be released before taking the PMC 863 * SX. 864 */ 865 if (PMC_SYSTEM_SAMPLING_ACTIVE() || PMC_PROC_IS_USING_PMCS(p)) { 866 PROC_UNLOCK(p); 867 VOP_UNLOCK(imgp->vp, 0); 868 pe.pm_credentialschanged = credential_changing; 869 pe.pm_entryaddr = imgp->entry_addr; 870 871 PMC_CALL_HOOK_X(td, PMC_FN_PROCESS_EXEC, (void *) &pe); 872 vn_lock(imgp->vp, LK_SHARED | LK_RETRY); 873 } else 874 PROC_UNLOCK(p); 875 #else /* !HWPMC_HOOKS */ 876 PROC_UNLOCK(p); 877 #endif 878 879 /* Set values passed into the program in registers. */ 880 if (p->p_sysent->sv_setregs) 881 (*p->p_sysent->sv_setregs)(td, imgp, 882 (u_long)(uintptr_t)stack_base); 883 else 884 exec_setregs(td, imgp, (u_long)(uintptr_t)stack_base); 885 886 vfs_mark_atime(imgp->vp, td->td_ucred); 887 888 SDT_PROBE1(proc, , , exec__success, args->fname); 889 890 exec_fail_dealloc: 891 if (imgp->firstpage != NULL) 892 exec_unmap_first_page(imgp); 893 894 if (imgp->vp != NULL) { 895 if (args->fname) 896 NDFREE(&nd, NDF_ONLY_PNBUF); 897 if (imgp->opened) 898 VOP_CLOSE(imgp->vp, FREAD, td->td_ucred, td); 899 if (error != 0) 900 vput(imgp->vp); 901 else 902 VOP_UNLOCK(imgp->vp, 0); 903 } 904 905 if (imgp->object != NULL) 906 vm_object_deallocate(imgp->object); 907 908 free(imgp->freepath, M_TEMP); 909 910 if (error == 0) { 911 PROC_LOCK(p); 912 if (p->p_ptevents & PTRACE_EXEC) 913 td->td_dbgflags |= TDB_EXEC; 914 PROC_UNLOCK(p); 915 916 /* 917 * Stop the process here if its stop event mask has 918 * the S_EXEC bit set. 919 */ 920 STOPEVENT(p, S_EXEC, 0); 921 } else { 922 exec_fail: 923 /* we're done here, clear P_INEXEC */ 924 PROC_LOCK(p); 925 p->p_flag &= ~P_INEXEC; 926 PROC_UNLOCK(p); 927 928 SDT_PROBE1(proc, , , exec__failure, error); 929 } 930 931 if (imgp->newcred != NULL && oldcred != NULL) 932 crfree(imgp->newcred); 933 934 #ifdef MAC 935 mac_execve_exit(imgp); 936 mac_execve_interpreter_exit(interpvplabel); 937 #endif 938 exec_free_args(args); 939 940 /* 941 * Handle deferred decrement of ref counts. 942 */ 943 if (oldtextvp != NULL) 944 vrele(oldtextvp); 945 #ifdef KTRACE 946 if (tracevp != NULL) 947 vrele(tracevp); 948 if (tracecred != NULL) 949 crfree(tracecred); 950 #endif 951 pargs_drop(oldargs); 952 pargs_drop(newargs); 953 if (oldsigacts != NULL) 954 sigacts_free(oldsigacts); 955 if (euip != NULL) 956 uifree(euip); 957 958 if (error && imgp->vmspace_destroyed) { 959 /* sorry, no more process anymore. exit gracefully */ 960 exit1(td, 0, SIGABRT); 961 /* NOT REACHED */ 962 } 963 964 #ifdef KTRACE 965 if (error == 0) 966 ktrprocctor(p); 967 #endif 968 969 return (error); 970 } 971 972 int 973 exec_map_first_page(imgp) 974 struct image_params *imgp; 975 { 976 int rv, i, after, initial_pagein; 977 vm_page_t ma[VM_INITIAL_PAGEIN]; 978 vm_object_t object; 979 980 if (imgp->firstpage != NULL) 981 exec_unmap_first_page(imgp); 982 983 object = imgp->vp->v_object; 984 if (object == NULL) 985 return (EACCES); 986 VM_OBJECT_WLOCK(object); 987 #if VM_NRESERVLEVEL > 0 988 vm_object_color(object, 0); 989 #endif 990 ma[0] = vm_page_grab(object, 0, VM_ALLOC_NORMAL | VM_ALLOC_NOBUSY); 991 if (ma[0]->valid != VM_PAGE_BITS_ALL) { 992 vm_page_xbusy(ma[0]); 993 if (!vm_pager_has_page(object, 0, NULL, &after)) { 994 vm_page_lock(ma[0]); 995 vm_page_free(ma[0]); 996 vm_page_unlock(ma[0]); 997 VM_OBJECT_WUNLOCK(object); 998 return (EIO); 999 } 1000 initial_pagein = min(after, VM_INITIAL_PAGEIN); 1001 KASSERT(initial_pagein <= object->size, 1002 ("%s: initial_pagein %d object->size %ju", 1003 __func__, initial_pagein, (uintmax_t )object->size)); 1004 for (i = 1; i < initial_pagein; i++) { 1005 if ((ma[i] = vm_page_next(ma[i - 1])) != NULL) { 1006 if (ma[i]->valid) 1007 break; 1008 if (vm_page_tryxbusy(ma[i])) 1009 break; 1010 } else { 1011 ma[i] = vm_page_alloc(object, i, 1012 VM_ALLOC_NORMAL); 1013 if (ma[i] == NULL) 1014 break; 1015 } 1016 } 1017 initial_pagein = i; 1018 rv = vm_pager_get_pages(object, ma, initial_pagein, NULL, NULL); 1019 if (rv != VM_PAGER_OK) { 1020 for (i = 0; i < initial_pagein; i++) { 1021 vm_page_lock(ma[i]); 1022 vm_page_free(ma[i]); 1023 vm_page_unlock(ma[i]); 1024 } 1025 VM_OBJECT_WUNLOCK(object); 1026 return (EIO); 1027 } 1028 vm_page_xunbusy(ma[0]); 1029 for (i = 1; i < initial_pagein; i++) 1030 vm_page_readahead_finish(ma[i]); 1031 } 1032 vm_page_lock(ma[0]); 1033 vm_page_hold(ma[0]); 1034 vm_page_activate(ma[0]); 1035 vm_page_unlock(ma[0]); 1036 VM_OBJECT_WUNLOCK(object); 1037 1038 imgp->firstpage = sf_buf_alloc(ma[0], 0); 1039 imgp->image_header = (char *)sf_buf_kva(imgp->firstpage); 1040 1041 return (0); 1042 } 1043 1044 void 1045 exec_unmap_first_page(imgp) 1046 struct image_params *imgp; 1047 { 1048 vm_page_t m; 1049 1050 if (imgp->firstpage != NULL) { 1051 m = sf_buf_page(imgp->firstpage); 1052 sf_buf_free(imgp->firstpage); 1053 imgp->firstpage = NULL; 1054 vm_page_lock(m); 1055 vm_page_unhold(m); 1056 vm_page_unlock(m); 1057 } 1058 } 1059 1060 /* 1061 * Destroy old address space, and allocate a new stack 1062 * The new stack is only SGROWSIZ large because it is grown 1063 * automatically in trap.c. 1064 */ 1065 int 1066 exec_new_vmspace(imgp, sv) 1067 struct image_params *imgp; 1068 struct sysentvec *sv; 1069 { 1070 int error; 1071 struct proc *p = imgp->proc; 1072 struct vmspace *vmspace = p->p_vmspace; 1073 vm_object_t obj; 1074 struct rlimit rlim_stack; 1075 vm_offset_t sv_minuser, stack_addr; 1076 vm_map_t map; 1077 u_long ssiz; 1078 1079 imgp->vmspace_destroyed = 1; 1080 imgp->sysent = sv; 1081 1082 /* May be called with Giant held */ 1083 EVENTHANDLER_INVOKE(process_exec, p, imgp); 1084 1085 /* 1086 * Blow away entire process VM, if address space not shared, 1087 * otherwise, create a new VM space so that other threads are 1088 * not disrupted 1089 */ 1090 map = &vmspace->vm_map; 1091 if (map_at_zero) 1092 sv_minuser = sv->sv_minuser; 1093 else 1094 sv_minuser = MAX(sv->sv_minuser, PAGE_SIZE); 1095 if (vmspace->vm_refcnt == 1 && vm_map_min(map) == sv_minuser && 1096 vm_map_max(map) == sv->sv_maxuser) { 1097 shmexit(vmspace); 1098 pmap_remove_pages(vmspace_pmap(vmspace)); 1099 vm_map_remove(map, vm_map_min(map), vm_map_max(map)); 1100 } else { 1101 error = vmspace_exec(p, sv_minuser, sv->sv_maxuser); 1102 if (error) 1103 return (error); 1104 vmspace = p->p_vmspace; 1105 map = &vmspace->vm_map; 1106 } 1107 1108 /* Map a shared page */ 1109 obj = sv->sv_shared_page_obj; 1110 if (obj != NULL) { 1111 vm_object_reference(obj); 1112 error = vm_map_fixed(map, obj, 0, 1113 sv->sv_shared_page_base, sv->sv_shared_page_len, 1114 VM_PROT_READ | VM_PROT_EXECUTE, 1115 VM_PROT_READ | VM_PROT_EXECUTE, 1116 MAP_INHERIT_SHARE | MAP_ACC_NO_CHARGE); 1117 if (error) { 1118 vm_object_deallocate(obj); 1119 return (error); 1120 } 1121 } 1122 1123 /* Allocate a new stack */ 1124 if (imgp->stack_sz != 0) { 1125 ssiz = trunc_page(imgp->stack_sz); 1126 PROC_LOCK(p); 1127 lim_rlimit_proc(p, RLIMIT_STACK, &rlim_stack); 1128 PROC_UNLOCK(p); 1129 if (ssiz > rlim_stack.rlim_max) 1130 ssiz = rlim_stack.rlim_max; 1131 if (ssiz > rlim_stack.rlim_cur) { 1132 rlim_stack.rlim_cur = ssiz; 1133 kern_setrlimit(curthread, RLIMIT_STACK, &rlim_stack); 1134 } 1135 } else if (sv->sv_maxssiz != NULL) { 1136 ssiz = *sv->sv_maxssiz; 1137 } else { 1138 ssiz = maxssiz; 1139 } 1140 stack_addr = sv->sv_usrstack - ssiz; 1141 error = vm_map_stack(map, stack_addr, (vm_size_t)ssiz, 1142 obj != NULL && imgp->stack_prot != 0 ? imgp->stack_prot : 1143 sv->sv_stackprot, 1144 VM_PROT_ALL, MAP_STACK_GROWS_DOWN); 1145 if (error) 1146 return (error); 1147 1148 /* 1149 * vm_ssize and vm_maxsaddr are somewhat antiquated concepts, but they 1150 * are still used to enforce the stack rlimit on the process stack. 1151 */ 1152 vmspace->vm_ssize = sgrowsiz >> PAGE_SHIFT; 1153 vmspace->vm_maxsaddr = (char *)stack_addr; 1154 1155 return (0); 1156 } 1157 1158 /* 1159 * Copy out argument and environment strings from the old process address 1160 * space into the temporary string buffer. 1161 */ 1162 int 1163 exec_copyin_args(struct image_args *args, char *fname, 1164 enum uio_seg segflg, char **argv, char **envv) 1165 { 1166 u_long argp, envp; 1167 int error; 1168 size_t length; 1169 1170 bzero(args, sizeof(*args)); 1171 if (argv == NULL) 1172 return (EFAULT); 1173 1174 /* 1175 * Allocate demand-paged memory for the file name, argument, and 1176 * environment strings. 1177 */ 1178 error = exec_alloc_args(args); 1179 if (error != 0) 1180 return (error); 1181 1182 /* 1183 * Copy the file name. 1184 */ 1185 if (fname != NULL) { 1186 args->fname = args->buf; 1187 error = (segflg == UIO_SYSSPACE) ? 1188 copystr(fname, args->fname, PATH_MAX, &length) : 1189 copyinstr(fname, args->fname, PATH_MAX, &length); 1190 if (error != 0) 1191 goto err_exit; 1192 } else 1193 length = 0; 1194 1195 args->begin_argv = args->buf + length; 1196 args->endp = args->begin_argv; 1197 args->stringspace = ARG_MAX; 1198 1199 /* 1200 * extract arguments first 1201 */ 1202 for (;;) { 1203 error = fueword(argv++, &argp); 1204 if (error == -1) { 1205 error = EFAULT; 1206 goto err_exit; 1207 } 1208 if (argp == 0) 1209 break; 1210 error = copyinstr((void *)(uintptr_t)argp, args->endp, 1211 args->stringspace, &length); 1212 if (error != 0) { 1213 if (error == ENAMETOOLONG) 1214 error = E2BIG; 1215 goto err_exit; 1216 } 1217 args->stringspace -= length; 1218 args->endp += length; 1219 args->argc++; 1220 } 1221 1222 args->begin_envv = args->endp; 1223 1224 /* 1225 * extract environment strings 1226 */ 1227 if (envv) { 1228 for (;;) { 1229 error = fueword(envv++, &envp); 1230 if (error == -1) { 1231 error = EFAULT; 1232 goto err_exit; 1233 } 1234 if (envp == 0) 1235 break; 1236 error = copyinstr((void *)(uintptr_t)envp, 1237 args->endp, args->stringspace, &length); 1238 if (error != 0) { 1239 if (error == ENAMETOOLONG) 1240 error = E2BIG; 1241 goto err_exit; 1242 } 1243 args->stringspace -= length; 1244 args->endp += length; 1245 args->envc++; 1246 } 1247 } 1248 1249 return (0); 1250 1251 err_exit: 1252 exec_free_args(args); 1253 return (error); 1254 } 1255 1256 int 1257 exec_copyin_data_fds(struct thread *td, struct image_args *args, 1258 const void *data, size_t datalen, const int *fds, size_t fdslen) 1259 { 1260 struct filedesc *ofdp; 1261 const char *p; 1262 int *kfds; 1263 int error; 1264 1265 memset(args, '\0', sizeof(*args)); 1266 ofdp = td->td_proc->p_fd; 1267 if (datalen >= ARG_MAX || fdslen > ofdp->fd_lastfile + 1) 1268 return (E2BIG); 1269 error = exec_alloc_args(args); 1270 if (error != 0) 1271 return (error); 1272 1273 args->begin_argv = args->buf; 1274 args->stringspace = ARG_MAX; 1275 1276 if (datalen > 0) { 1277 /* 1278 * Argument buffer has been provided. Copy it into the 1279 * kernel as a single string and add a terminating null 1280 * byte. 1281 */ 1282 error = copyin(data, args->begin_argv, datalen); 1283 if (error != 0) 1284 goto err_exit; 1285 args->begin_argv[datalen] = '\0'; 1286 args->endp = args->begin_argv + datalen + 1; 1287 args->stringspace -= datalen + 1; 1288 1289 /* 1290 * Traditional argument counting. Count the number of 1291 * null bytes. 1292 */ 1293 for (p = args->begin_argv; p < args->endp; ++p) 1294 if (*p == '\0') 1295 ++args->argc; 1296 } else { 1297 /* No argument buffer provided. */ 1298 args->endp = args->begin_argv; 1299 } 1300 /* There are no environment variables. */ 1301 args->begin_envv = args->endp; 1302 1303 /* Create new file descriptor table. */ 1304 kfds = malloc(fdslen * sizeof(int), M_TEMP, M_WAITOK); 1305 error = copyin(fds, kfds, fdslen * sizeof(int)); 1306 if (error != 0) { 1307 free(kfds, M_TEMP); 1308 goto err_exit; 1309 } 1310 error = fdcopy_remapped(ofdp, kfds, fdslen, &args->fdp); 1311 free(kfds, M_TEMP); 1312 if (error != 0) 1313 goto err_exit; 1314 1315 return (0); 1316 err_exit: 1317 exec_free_args(args); 1318 return (error); 1319 } 1320 1321 struct exec_args_kva { 1322 vm_offset_t addr; 1323 SLIST_ENTRY(exec_args_kva) next; 1324 }; 1325 1326 static DPCPU_DEFINE(struct exec_args_kva *, exec_args_kva); 1327 1328 static SLIST_HEAD(, exec_args_kva) exec_args_kva_freelist; 1329 static struct mtx exec_args_kva_mtx; 1330 1331 static void 1332 exec_prealloc_args_kva(void *arg __unused) 1333 { 1334 struct exec_args_kva *argkva; 1335 u_int i; 1336 1337 SLIST_INIT(&exec_args_kva_freelist); 1338 mtx_init(&exec_args_kva_mtx, "exec args kva", NULL, MTX_DEF); 1339 for (i = 0; i < exec_map_entries; i++) { 1340 argkva = malloc(sizeof(*argkva), M_PARGS, M_WAITOK); 1341 argkva->addr = kmap_alloc_wait(exec_map, exec_map_entry_size); 1342 SLIST_INSERT_HEAD(&exec_args_kva_freelist, argkva, next); 1343 } 1344 } 1345 SYSINIT(exec_args_kva, SI_SUB_EXEC, SI_ORDER_ANY, exec_prealloc_args_kva, NULL); 1346 1347 static vm_offset_t 1348 exec_alloc_args_kva(void **cookie) 1349 { 1350 struct exec_args_kva *argkva; 1351 1352 argkva = (void *)atomic_readandclear_ptr( 1353 (uintptr_t *)DPCPU_PTR(exec_args_kva)); 1354 if (argkva == NULL) { 1355 mtx_lock(&exec_args_kva_mtx); 1356 while ((argkva = SLIST_FIRST(&exec_args_kva_freelist)) == NULL) 1357 (void)mtx_sleep(&exec_args_kva_freelist, 1358 &exec_args_kva_mtx, 0, "execkva", 0); 1359 SLIST_REMOVE_HEAD(&exec_args_kva_freelist, next); 1360 mtx_unlock(&exec_args_kva_mtx); 1361 } 1362 *(struct exec_args_kva **)cookie = argkva; 1363 return (argkva->addr); 1364 } 1365 1366 static void 1367 exec_free_args_kva(void *cookie) 1368 { 1369 struct exec_args_kva *argkva; 1370 vm_offset_t base; 1371 1372 argkva = cookie; 1373 base = argkva->addr; 1374 1375 vm_map_madvise(exec_map, base, base + exec_map_entry_size, MADV_FREE); 1376 if (!atomic_cmpset_ptr((uintptr_t *)DPCPU_PTR(exec_args_kva), 1377 (uintptr_t)NULL, (uintptr_t)argkva)) { 1378 mtx_lock(&exec_args_kva_mtx); 1379 SLIST_INSERT_HEAD(&exec_args_kva_freelist, argkva, next); 1380 wakeup_one(&exec_args_kva_freelist); 1381 mtx_unlock(&exec_args_kva_mtx); 1382 } 1383 } 1384 1385 /* 1386 * Allocate temporary demand-paged, zero-filled memory for the file name, 1387 * argument, and environment strings. 1388 */ 1389 int 1390 exec_alloc_args(struct image_args *args) 1391 { 1392 1393 args->buf = (char *)exec_alloc_args_kva(&args->bufkva); 1394 return (0); 1395 } 1396 1397 void 1398 exec_free_args(struct image_args *args) 1399 { 1400 1401 if (args->buf != NULL) { 1402 exec_free_args_kva(args->bufkva); 1403 args->buf = NULL; 1404 } 1405 if (args->fname_buf != NULL) { 1406 free(args->fname_buf, M_TEMP); 1407 args->fname_buf = NULL; 1408 } 1409 if (args->fdp != NULL) 1410 fdescfree_remapped(args->fdp); 1411 } 1412 1413 /* 1414 * Copy strings out to the new process address space, constructing new arg 1415 * and env vector tables. Return a pointer to the base so that it can be used 1416 * as the initial stack pointer. 1417 */ 1418 register_t * 1419 exec_copyout_strings(imgp) 1420 struct image_params *imgp; 1421 { 1422 int argc, envc; 1423 char **vectp; 1424 char *stringp; 1425 uintptr_t destp; 1426 register_t *stack_base; 1427 struct ps_strings *arginfo; 1428 struct proc *p; 1429 size_t execpath_len; 1430 int szsigcode, szps; 1431 char canary[sizeof(long) * 8]; 1432 1433 szps = sizeof(pagesizes[0]) * MAXPAGESIZES; 1434 /* 1435 * Calculate string base and vector table pointers. 1436 * Also deal with signal trampoline code for this exec type. 1437 */ 1438 if (imgp->execpath != NULL && imgp->auxargs != NULL) 1439 execpath_len = strlen(imgp->execpath) + 1; 1440 else 1441 execpath_len = 0; 1442 p = imgp->proc; 1443 szsigcode = 0; 1444 arginfo = (struct ps_strings *)p->p_sysent->sv_psstrings; 1445 if (p->p_sysent->sv_sigcode_base == 0) { 1446 if (p->p_sysent->sv_szsigcode != NULL) 1447 szsigcode = *(p->p_sysent->sv_szsigcode); 1448 } 1449 destp = (uintptr_t)arginfo; 1450 1451 /* 1452 * install sigcode 1453 */ 1454 if (szsigcode != 0) { 1455 destp -= szsigcode; 1456 destp = rounddown2(destp, sizeof(void *)); 1457 copyout(p->p_sysent->sv_sigcode, (void *)destp, szsigcode); 1458 } 1459 1460 /* 1461 * Copy the image path for the rtld. 1462 */ 1463 if (execpath_len != 0) { 1464 destp -= execpath_len; 1465 imgp->execpathp = destp; 1466 copyout(imgp->execpath, (void *)destp, execpath_len); 1467 } 1468 1469 /* 1470 * Prepare the canary for SSP. 1471 */ 1472 arc4rand(canary, sizeof(canary), 0); 1473 destp -= sizeof(canary); 1474 imgp->canary = destp; 1475 copyout(canary, (void *)destp, sizeof(canary)); 1476 imgp->canarylen = sizeof(canary); 1477 1478 /* 1479 * Prepare the pagesizes array. 1480 */ 1481 destp -= szps; 1482 destp = rounddown2(destp, sizeof(void *)); 1483 imgp->pagesizes = destp; 1484 copyout(pagesizes, (void *)destp, szps); 1485 imgp->pagesizeslen = szps; 1486 1487 destp -= ARG_MAX - imgp->args->stringspace; 1488 destp = rounddown2(destp, sizeof(void *)); 1489 1490 /* 1491 * If we have a valid auxargs ptr, prepare some room 1492 * on the stack. 1493 */ 1494 if (imgp->auxargs) { 1495 /* 1496 * 'AT_COUNT*2' is size for the ELF Auxargs data. This is for 1497 * lower compatibility. 1498 */ 1499 imgp->auxarg_size = (imgp->auxarg_size) ? imgp->auxarg_size : 1500 (AT_COUNT * 2); 1501 /* 1502 * The '+ 2' is for the null pointers at the end of each of 1503 * the arg and env vector sets,and imgp->auxarg_size is room 1504 * for argument of Runtime loader. 1505 */ 1506 vectp = (char **)(destp - (imgp->args->argc + 1507 imgp->args->envc + 2 + imgp->auxarg_size) 1508 * sizeof(char *)); 1509 } else { 1510 /* 1511 * The '+ 2' is for the null pointers at the end of each of 1512 * the arg and env vector sets 1513 */ 1514 vectp = (char **)(destp - (imgp->args->argc + imgp->args->envc 1515 + 2) * sizeof(char *)); 1516 } 1517 1518 /* 1519 * vectp also becomes our initial stack base 1520 */ 1521 stack_base = (register_t *)vectp; 1522 1523 stringp = imgp->args->begin_argv; 1524 argc = imgp->args->argc; 1525 envc = imgp->args->envc; 1526 1527 /* 1528 * Copy out strings - arguments and environment. 1529 */ 1530 copyout(stringp, (void *)destp, ARG_MAX - imgp->args->stringspace); 1531 1532 /* 1533 * Fill in "ps_strings" struct for ps, w, etc. 1534 */ 1535 suword(&arginfo->ps_argvstr, (long)(intptr_t)vectp); 1536 suword32(&arginfo->ps_nargvstr, argc); 1537 1538 /* 1539 * Fill in argument portion of vector table. 1540 */ 1541 for (; argc > 0; --argc) { 1542 suword(vectp++, (long)(intptr_t)destp); 1543 while (*stringp++ != 0) 1544 destp++; 1545 destp++; 1546 } 1547 1548 /* a null vector table pointer separates the argp's from the envp's */ 1549 suword(vectp++, 0); 1550 1551 suword(&arginfo->ps_envstr, (long)(intptr_t)vectp); 1552 suword32(&arginfo->ps_nenvstr, envc); 1553 1554 /* 1555 * Fill in environment portion of vector table. 1556 */ 1557 for (; envc > 0; --envc) { 1558 suword(vectp++, (long)(intptr_t)destp); 1559 while (*stringp++ != 0) 1560 destp++; 1561 destp++; 1562 } 1563 1564 /* end of vector table is a null pointer */ 1565 suword(vectp, 0); 1566 1567 return (stack_base); 1568 } 1569 1570 /* 1571 * Check permissions of file to execute. 1572 * Called with imgp->vp locked. 1573 * Return 0 for success or error code on failure. 1574 */ 1575 int 1576 exec_check_permissions(imgp) 1577 struct image_params *imgp; 1578 { 1579 struct vnode *vp = imgp->vp; 1580 struct vattr *attr = imgp->attr; 1581 struct thread *td; 1582 int error, writecount; 1583 1584 td = curthread; 1585 1586 /* Get file attributes */ 1587 error = VOP_GETATTR(vp, attr, td->td_ucred); 1588 if (error) 1589 return (error); 1590 1591 #ifdef MAC 1592 error = mac_vnode_check_exec(td->td_ucred, imgp->vp, imgp); 1593 if (error) 1594 return (error); 1595 #endif 1596 1597 /* 1598 * 1) Check if file execution is disabled for the filesystem that 1599 * this file resides on. 1600 * 2) Ensure that at least one execute bit is on. Otherwise, a 1601 * privileged user will always succeed, and we don't want this 1602 * to happen unless the file really is executable. 1603 * 3) Ensure that the file is a regular file. 1604 */ 1605 if ((vp->v_mount->mnt_flag & MNT_NOEXEC) || 1606 (attr->va_mode & (S_IXUSR | S_IXGRP | S_IXOTH)) == 0 || 1607 (attr->va_type != VREG)) 1608 return (EACCES); 1609 1610 /* 1611 * Zero length files can't be exec'd 1612 */ 1613 if (attr->va_size == 0) 1614 return (ENOEXEC); 1615 1616 /* 1617 * Check for execute permission to file based on current credentials. 1618 */ 1619 error = VOP_ACCESS(vp, VEXEC, td->td_ucred, td); 1620 if (error) 1621 return (error); 1622 1623 /* 1624 * Check number of open-for-writes on the file and deny execution 1625 * if there are any. 1626 */ 1627 error = VOP_GET_WRITECOUNT(vp, &writecount); 1628 if (error != 0) 1629 return (error); 1630 if (writecount != 0) 1631 return (ETXTBSY); 1632 1633 /* 1634 * Call filesystem specific open routine (which does nothing in the 1635 * general case). 1636 */ 1637 error = VOP_OPEN(vp, FREAD, td->td_ucred, td, NULL); 1638 if (error == 0) 1639 imgp->opened = 1; 1640 return (error); 1641 } 1642 1643 /* 1644 * Exec handler registration 1645 */ 1646 int 1647 exec_register(execsw_arg) 1648 const struct execsw *execsw_arg; 1649 { 1650 const struct execsw **es, **xs, **newexecsw; 1651 int count = 2; /* New slot and trailing NULL */ 1652 1653 if (execsw) 1654 for (es = execsw; *es; es++) 1655 count++; 1656 newexecsw = malloc(count * sizeof(*es), M_TEMP, M_WAITOK); 1657 xs = newexecsw; 1658 if (execsw) 1659 for (es = execsw; *es; es++) 1660 *xs++ = *es; 1661 *xs++ = execsw_arg; 1662 *xs = NULL; 1663 if (execsw) 1664 free(execsw, M_TEMP); 1665 execsw = newexecsw; 1666 return (0); 1667 } 1668 1669 int 1670 exec_unregister(execsw_arg) 1671 const struct execsw *execsw_arg; 1672 { 1673 const struct execsw **es, **xs, **newexecsw; 1674 int count = 1; 1675 1676 if (execsw == NULL) 1677 panic("unregister with no handlers left?\n"); 1678 1679 for (es = execsw; *es; es++) { 1680 if (*es == execsw_arg) 1681 break; 1682 } 1683 if (*es == NULL) 1684 return (ENOENT); 1685 for (es = execsw; *es; es++) 1686 if (*es != execsw_arg) 1687 count++; 1688 newexecsw = malloc(count * sizeof(*es), M_TEMP, M_WAITOK); 1689 xs = newexecsw; 1690 for (es = execsw; *es; es++) 1691 if (*es != execsw_arg) 1692 *xs++ = *es; 1693 *xs = NULL; 1694 if (execsw) 1695 free(execsw, M_TEMP); 1696 execsw = newexecsw; 1697 return (0); 1698 } 1699