1 /*- 2 * SPDX-License-Identifier: BSD-2-Clause-FreeBSD 3 * 4 * Copyright (c) 1993, David Greenman 5 * All rights reserved. 6 * 7 * Redistribution and use in source and binary forms, with or without 8 * modification, are permitted provided that the following conditions 9 * are met: 10 * 1. Redistributions of source code must retain the above copyright 11 * notice, this list of conditions and the following disclaimer. 12 * 2. Redistributions in binary form must reproduce the above copyright 13 * notice, this list of conditions and the following disclaimer in the 14 * documentation and/or other materials provided with the distribution. 15 * 16 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND 17 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 18 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 19 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE 20 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 21 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 22 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 23 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 24 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 25 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 26 * SUCH DAMAGE. 27 */ 28 29 #include <sys/cdefs.h> 30 __FBSDID("$FreeBSD$"); 31 32 #include "opt_capsicum.h" 33 #include "opt_hwpmc_hooks.h" 34 #include "opt_ktrace.h" 35 #include "opt_vm.h" 36 37 #include <sys/param.h> 38 #include <sys/systm.h> 39 #include <sys/acct.h> 40 #include <sys/capsicum.h> 41 #include <sys/eventhandler.h> 42 #include <sys/exec.h> 43 #include <sys/fcntl.h> 44 #include <sys/filedesc.h> 45 #include <sys/imgact.h> 46 #include <sys/imgact_elf.h> 47 #include <sys/kernel.h> 48 #include <sys/lock.h> 49 #include <sys/malloc.h> 50 #include <sys/mman.h> 51 #include <sys/mount.h> 52 #include <sys/mutex.h> 53 #include <sys/namei.h> 54 #include <sys/pioctl.h> 55 #include <sys/priv.h> 56 #include <sys/proc.h> 57 #include <sys/ptrace.h> 58 #include <sys/resourcevar.h> 59 #include <sys/rwlock.h> 60 #include <sys/sched.h> 61 #include <sys/sdt.h> 62 #include <sys/sf_buf.h> 63 #include <sys/shm.h> 64 #include <sys/signalvar.h> 65 #include <sys/smp.h> 66 #include <sys/stat.h> 67 #include <sys/syscallsubr.h> 68 #include <sys/sysctl.h> 69 #include <sys/sysent.h> 70 #include <sys/sysproto.h> 71 #include <sys/vnode.h> 72 #include <sys/wait.h> 73 #ifdef KTRACE 74 #include <sys/ktrace.h> 75 #endif 76 77 #include <vm/vm.h> 78 #include <vm/vm_param.h> 79 #include <vm/pmap.h> 80 #include <vm/vm_page.h> 81 #include <vm/vm_map.h> 82 #include <vm/vm_kern.h> 83 #include <vm/vm_extern.h> 84 #include <vm/vm_object.h> 85 #include <vm/vm_pager.h> 86 87 #ifdef HWPMC_HOOKS 88 #include <sys/pmckern.h> 89 #endif 90 91 #include <machine/reg.h> 92 93 #include <security/audit/audit.h> 94 #include <security/mac/mac_framework.h> 95 96 #ifdef KDTRACE_HOOKS 97 #include <sys/dtrace_bsd.h> 98 dtrace_execexit_func_t dtrace_fasttrap_exec; 99 #endif 100 101 SDT_PROVIDER_DECLARE(proc); 102 SDT_PROBE_DEFINE1(proc, , , exec, "char *"); 103 SDT_PROBE_DEFINE1(proc, , , exec__failure, "int"); 104 SDT_PROBE_DEFINE1(proc, , , exec__success, "char *"); 105 106 MALLOC_DEFINE(M_PARGS, "proc-args", "Process arguments"); 107 108 int coredump_pack_fileinfo = 1; 109 SYSCTL_INT(_kern, OID_AUTO, coredump_pack_fileinfo, CTLFLAG_RWTUN, 110 &coredump_pack_fileinfo, 0, 111 "Enable file path packing in 'procstat -f' coredump notes"); 112 113 int coredump_pack_vmmapinfo = 1; 114 SYSCTL_INT(_kern, OID_AUTO, coredump_pack_vmmapinfo, CTLFLAG_RWTUN, 115 &coredump_pack_vmmapinfo, 0, 116 "Enable file path packing in 'procstat -v' coredump notes"); 117 118 static int sysctl_kern_ps_strings(SYSCTL_HANDLER_ARGS); 119 static int sysctl_kern_usrstack(SYSCTL_HANDLER_ARGS); 120 static int sysctl_kern_stackprot(SYSCTL_HANDLER_ARGS); 121 static int do_execve(struct thread *td, struct image_args *args, 122 struct mac *mac_p); 123 124 /* XXX This should be vm_size_t. */ 125 SYSCTL_PROC(_kern, KERN_PS_STRINGS, ps_strings, CTLTYPE_ULONG|CTLFLAG_RD| 126 CTLFLAG_CAPRD|CTLFLAG_MPSAFE, NULL, 0, sysctl_kern_ps_strings, "LU", ""); 127 128 /* XXX This should be vm_size_t. */ 129 SYSCTL_PROC(_kern, KERN_USRSTACK, usrstack, CTLTYPE_ULONG|CTLFLAG_RD| 130 CTLFLAG_CAPRD|CTLFLAG_MPSAFE, NULL, 0, sysctl_kern_usrstack, "LU", ""); 131 132 SYSCTL_PROC(_kern, OID_AUTO, stackprot, CTLTYPE_INT|CTLFLAG_RD|CTLFLAG_MPSAFE, 133 NULL, 0, sysctl_kern_stackprot, "I", ""); 134 135 u_long ps_arg_cache_limit = PAGE_SIZE / 16; 136 SYSCTL_ULONG(_kern, OID_AUTO, ps_arg_cache_limit, CTLFLAG_RW, 137 &ps_arg_cache_limit, 0, ""); 138 139 static int disallow_high_osrel; 140 SYSCTL_INT(_kern, OID_AUTO, disallow_high_osrel, CTLFLAG_RW, 141 &disallow_high_osrel, 0, 142 "Disallow execution of binaries built for higher version of the world"); 143 144 static int map_at_zero = 0; 145 SYSCTL_INT(_security_bsd, OID_AUTO, map_at_zero, CTLFLAG_RWTUN, &map_at_zero, 0, 146 "Permit processes to map an object at virtual address 0."); 147 148 static int 149 sysctl_kern_ps_strings(SYSCTL_HANDLER_ARGS) 150 { 151 struct proc *p; 152 int error; 153 154 p = curproc; 155 #ifdef SCTL_MASK32 156 if (req->flags & SCTL_MASK32) { 157 unsigned int val; 158 val = (unsigned int)p->p_sysent->sv_psstrings; 159 error = SYSCTL_OUT(req, &val, sizeof(val)); 160 } else 161 #endif 162 error = SYSCTL_OUT(req, &p->p_sysent->sv_psstrings, 163 sizeof(p->p_sysent->sv_psstrings)); 164 return error; 165 } 166 167 static int 168 sysctl_kern_usrstack(SYSCTL_HANDLER_ARGS) 169 { 170 struct proc *p; 171 int error; 172 173 p = curproc; 174 #ifdef SCTL_MASK32 175 if (req->flags & SCTL_MASK32) { 176 unsigned int val; 177 val = (unsigned int)p->p_sysent->sv_usrstack; 178 error = SYSCTL_OUT(req, &val, sizeof(val)); 179 } else 180 #endif 181 error = SYSCTL_OUT(req, &p->p_sysent->sv_usrstack, 182 sizeof(p->p_sysent->sv_usrstack)); 183 return error; 184 } 185 186 static int 187 sysctl_kern_stackprot(SYSCTL_HANDLER_ARGS) 188 { 189 struct proc *p; 190 191 p = curproc; 192 return (SYSCTL_OUT(req, &p->p_sysent->sv_stackprot, 193 sizeof(p->p_sysent->sv_stackprot))); 194 } 195 196 /* 197 * Each of the items is a pointer to a `const struct execsw', hence the 198 * double pointer here. 199 */ 200 static const struct execsw **execsw; 201 202 #ifndef _SYS_SYSPROTO_H_ 203 struct execve_args { 204 char *fname; 205 char **argv; 206 char **envv; 207 }; 208 #endif 209 210 int 211 sys_execve(struct thread *td, struct execve_args *uap) 212 { 213 struct image_args args; 214 struct vmspace *oldvmspace; 215 int error; 216 217 error = pre_execve(td, &oldvmspace); 218 if (error != 0) 219 return (error); 220 error = exec_copyin_args(&args, uap->fname, UIO_USERSPACE, 221 uap->argv, uap->envv); 222 if (error == 0) 223 error = kern_execve(td, &args, NULL); 224 post_execve(td, error, oldvmspace); 225 return (error); 226 } 227 228 #ifndef _SYS_SYSPROTO_H_ 229 struct fexecve_args { 230 int fd; 231 char **argv; 232 char **envv; 233 } 234 #endif 235 int 236 sys_fexecve(struct thread *td, struct fexecve_args *uap) 237 { 238 struct image_args args; 239 struct vmspace *oldvmspace; 240 int error; 241 242 error = pre_execve(td, &oldvmspace); 243 if (error != 0) 244 return (error); 245 error = exec_copyin_args(&args, NULL, UIO_SYSSPACE, 246 uap->argv, uap->envv); 247 if (error == 0) { 248 args.fd = uap->fd; 249 error = kern_execve(td, &args, NULL); 250 } 251 post_execve(td, error, oldvmspace); 252 return (error); 253 } 254 255 #ifndef _SYS_SYSPROTO_H_ 256 struct __mac_execve_args { 257 char *fname; 258 char **argv; 259 char **envv; 260 struct mac *mac_p; 261 }; 262 #endif 263 264 int 265 sys___mac_execve(struct thread *td, struct __mac_execve_args *uap) 266 { 267 #ifdef MAC 268 struct image_args args; 269 struct vmspace *oldvmspace; 270 int error; 271 272 error = pre_execve(td, &oldvmspace); 273 if (error != 0) 274 return (error); 275 error = exec_copyin_args(&args, uap->fname, UIO_USERSPACE, 276 uap->argv, uap->envv); 277 if (error == 0) 278 error = kern_execve(td, &args, uap->mac_p); 279 post_execve(td, error, oldvmspace); 280 return (error); 281 #else 282 return (ENOSYS); 283 #endif 284 } 285 286 int 287 pre_execve(struct thread *td, struct vmspace **oldvmspace) 288 { 289 struct proc *p; 290 int error; 291 292 KASSERT(td == curthread, ("non-current thread %p", td)); 293 error = 0; 294 p = td->td_proc; 295 if ((p->p_flag & P_HADTHREADS) != 0) { 296 PROC_LOCK(p); 297 if (thread_single(p, SINGLE_BOUNDARY) != 0) 298 error = ERESTART; 299 PROC_UNLOCK(p); 300 } 301 KASSERT(error != 0 || (td->td_pflags & TDP_EXECVMSPC) == 0, 302 ("nested execve")); 303 *oldvmspace = p->p_vmspace; 304 return (error); 305 } 306 307 void 308 post_execve(struct thread *td, int error, struct vmspace *oldvmspace) 309 { 310 struct proc *p; 311 312 KASSERT(td == curthread, ("non-current thread %p", td)); 313 p = td->td_proc; 314 if ((p->p_flag & P_HADTHREADS) != 0) { 315 PROC_LOCK(p); 316 /* 317 * If success, we upgrade to SINGLE_EXIT state to 318 * force other threads to suicide. 319 */ 320 if (error == EJUSTRETURN) 321 thread_single(p, SINGLE_EXIT); 322 else 323 thread_single_end(p, SINGLE_BOUNDARY); 324 PROC_UNLOCK(p); 325 } 326 if ((td->td_pflags & TDP_EXECVMSPC) != 0) { 327 KASSERT(p->p_vmspace != oldvmspace, 328 ("oldvmspace still used")); 329 vmspace_free(oldvmspace); 330 td->td_pflags &= ~TDP_EXECVMSPC; 331 } 332 } 333 334 /* 335 * XXX: kern_execve has the astonishing property of not always returning to 336 * the caller. If sufficiently bad things happen during the call to 337 * do_execve(), it can end up calling exit1(); as a result, callers must 338 * avoid doing anything which they might need to undo (e.g., allocating 339 * memory). 340 */ 341 int 342 kern_execve(struct thread *td, struct image_args *args, struct mac *mac_p) 343 { 344 345 AUDIT_ARG_ARGV(args->begin_argv, args->argc, 346 exec_args_get_begin_envv(args) - args->begin_argv); 347 AUDIT_ARG_ENVV(exec_args_get_begin_envv(args), args->envc, 348 args->endp - exec_args_get_begin_envv(args)); 349 return (do_execve(td, args, mac_p)); 350 } 351 352 /* 353 * In-kernel implementation of execve(). All arguments are assumed to be 354 * userspace pointers from the passed thread. 355 */ 356 static int 357 do_execve(struct thread *td, struct image_args *args, struct mac *mac_p) 358 { 359 struct proc *p = td->td_proc; 360 struct nameidata nd; 361 struct ucred *oldcred; 362 struct uidinfo *euip = NULL; 363 uintptr_t stack_base; 364 struct image_params image_params, *imgp; 365 struct vattr attr; 366 int (*img_first)(struct image_params *); 367 struct pargs *oldargs = NULL, *newargs = NULL; 368 struct sigacts *oldsigacts = NULL, *newsigacts = NULL; 369 #ifdef KTRACE 370 struct vnode *tracevp = NULL; 371 struct ucred *tracecred = NULL; 372 #endif 373 struct vnode *oldtextvp = NULL, *newtextvp; 374 int credential_changing; 375 #ifdef MAC 376 struct label *interpvplabel = NULL; 377 int will_transition; 378 #endif 379 #ifdef HWPMC_HOOKS 380 struct pmckern_procexec pe; 381 #endif 382 int error, i, orig_osrel; 383 uint32_t orig_fctl0; 384 static const char fexecv_proc_title[] = "(fexecv)"; 385 386 imgp = &image_params; 387 388 /* 389 * Lock the process and set the P_INEXEC flag to indicate that 390 * it should be left alone until we're done here. This is 391 * necessary to avoid race conditions - e.g. in ptrace() - 392 * that might allow a local user to illicitly obtain elevated 393 * privileges. 394 */ 395 PROC_LOCK(p); 396 KASSERT((p->p_flag & P_INEXEC) == 0, 397 ("%s(): process already has P_INEXEC flag", __func__)); 398 p->p_flag |= P_INEXEC; 399 PROC_UNLOCK(p); 400 401 /* 402 * Initialize part of the common data 403 */ 404 bzero(imgp, sizeof(*imgp)); 405 imgp->proc = p; 406 imgp->attr = &attr; 407 imgp->args = args; 408 oldcred = p->p_ucred; 409 orig_osrel = p->p_osrel; 410 orig_fctl0 = p->p_fctl0; 411 412 #ifdef MAC 413 error = mac_execve_enter(imgp, mac_p); 414 if (error) 415 goto exec_fail; 416 #endif 417 418 /* 419 * Translate the file name. namei() returns a vnode pointer 420 * in ni_vp among other things. 421 * 422 * XXXAUDIT: It would be desirable to also audit the name of the 423 * interpreter if this is an interpreted binary. 424 */ 425 if (args->fname != NULL) { 426 NDINIT(&nd, LOOKUP, ISOPEN | LOCKLEAF | LOCKSHARED | FOLLOW | 427 SAVENAME | AUDITVNODE1, UIO_SYSSPACE, args->fname, td); 428 } 429 430 SDT_PROBE1(proc, , , exec, args->fname); 431 432 interpret: 433 if (args->fname != NULL) { 434 #ifdef CAPABILITY_MODE 435 /* 436 * While capability mode can't reach this point via direct 437 * path arguments to execve(), we also don't allow 438 * interpreters to be used in capability mode (for now). 439 * Catch indirect lookups and return a permissions error. 440 */ 441 if (IN_CAPABILITY_MODE(td)) { 442 error = ECAPMODE; 443 goto exec_fail; 444 } 445 #endif 446 error = namei(&nd); 447 if (error) 448 goto exec_fail; 449 450 newtextvp = nd.ni_vp; 451 imgp->vp = newtextvp; 452 } else { 453 AUDIT_ARG_FD(args->fd); 454 /* 455 * Descriptors opened only with O_EXEC or O_RDONLY are allowed. 456 */ 457 error = fgetvp_exec(td, args->fd, &cap_fexecve_rights, &newtextvp); 458 if (error) 459 goto exec_fail; 460 vn_lock(newtextvp, LK_SHARED | LK_RETRY); 461 AUDIT_ARG_VNODE1(newtextvp); 462 imgp->vp = newtextvp; 463 } 464 465 /* 466 * Check file permissions. Also 'opens' file and sets its vnode to 467 * text mode. 468 */ 469 error = exec_check_permissions(imgp); 470 if (error) 471 goto exec_fail_dealloc; 472 473 imgp->object = imgp->vp->v_object; 474 if (imgp->object != NULL) 475 vm_object_reference(imgp->object); 476 477 error = exec_map_first_page(imgp); 478 if (error) 479 goto exec_fail_dealloc; 480 481 imgp->proc->p_osrel = 0; 482 imgp->proc->p_fctl0 = 0; 483 484 /* 485 * Implement image setuid/setgid. 486 * 487 * Determine new credentials before attempting image activators 488 * so that it can be used by process_exec handlers to determine 489 * credential/setid changes. 490 * 491 * Don't honor setuid/setgid if the filesystem prohibits it or if 492 * the process is being traced. 493 * 494 * We disable setuid/setgid/etc in capability mode on the basis 495 * that most setugid applications are not written with that 496 * environment in mind, and will therefore almost certainly operate 497 * incorrectly. In principle there's no reason that setugid 498 * applications might not be useful in capability mode, so we may want 499 * to reconsider this conservative design choice in the future. 500 * 501 * XXXMAC: For the time being, use NOSUID to also prohibit 502 * transitions on the file system. 503 */ 504 credential_changing = 0; 505 credential_changing |= (attr.va_mode & S_ISUID) && 506 oldcred->cr_uid != attr.va_uid; 507 credential_changing |= (attr.va_mode & S_ISGID) && 508 oldcred->cr_gid != attr.va_gid; 509 #ifdef MAC 510 will_transition = mac_vnode_execve_will_transition(oldcred, imgp->vp, 511 interpvplabel, imgp); 512 credential_changing |= will_transition; 513 #endif 514 515 /* Don't inherit PROC_PDEATHSIG_CTL value if setuid/setgid. */ 516 if (credential_changing) 517 imgp->proc->p_pdeathsig = 0; 518 519 if (credential_changing && 520 #ifdef CAPABILITY_MODE 521 ((oldcred->cr_flags & CRED_FLAG_CAPMODE) == 0) && 522 #endif 523 (imgp->vp->v_mount->mnt_flag & MNT_NOSUID) == 0 && 524 (p->p_flag & P_TRACED) == 0) { 525 imgp->credential_setid = true; 526 VOP_UNLOCK(imgp->vp); 527 imgp->newcred = crdup(oldcred); 528 if (attr.va_mode & S_ISUID) { 529 euip = uifind(attr.va_uid); 530 change_euid(imgp->newcred, euip); 531 } 532 vn_lock(imgp->vp, LK_SHARED | LK_RETRY); 533 if (attr.va_mode & S_ISGID) 534 change_egid(imgp->newcred, attr.va_gid); 535 /* 536 * Implement correct POSIX saved-id behavior. 537 * 538 * XXXMAC: Note that the current logic will save the 539 * uid and gid if a MAC domain transition occurs, even 540 * though maybe it shouldn't. 541 */ 542 change_svuid(imgp->newcred, imgp->newcred->cr_uid); 543 change_svgid(imgp->newcred, imgp->newcred->cr_gid); 544 } else { 545 /* 546 * Implement correct POSIX saved-id behavior. 547 * 548 * XXX: It's not clear that the existing behavior is 549 * POSIX-compliant. A number of sources indicate that the 550 * saved uid/gid should only be updated if the new ruid is 551 * not equal to the old ruid, or the new euid is not equal 552 * to the old euid and the new euid is not equal to the old 553 * ruid. The FreeBSD code always updates the saved uid/gid. 554 * Also, this code uses the new (replaced) euid and egid as 555 * the source, which may or may not be the right ones to use. 556 */ 557 if (oldcred->cr_svuid != oldcred->cr_uid || 558 oldcred->cr_svgid != oldcred->cr_gid) { 559 VOP_UNLOCK(imgp->vp); 560 imgp->newcred = crdup(oldcred); 561 vn_lock(imgp->vp, LK_SHARED | LK_RETRY); 562 change_svuid(imgp->newcred, imgp->newcred->cr_uid); 563 change_svgid(imgp->newcred, imgp->newcred->cr_gid); 564 } 565 } 566 /* The new credentials are installed into the process later. */ 567 568 /* 569 * Do the best to calculate the full path to the image file. 570 */ 571 if (args->fname != NULL && args->fname[0] == '/') 572 imgp->execpath = args->fname; 573 else { 574 VOP_UNLOCK(imgp->vp); 575 if (vn_fullpath(td, imgp->vp, &imgp->execpath, 576 &imgp->freepath) != 0) 577 imgp->execpath = args->fname; 578 vn_lock(imgp->vp, LK_SHARED | LK_RETRY); 579 } 580 581 /* 582 * If the current process has a special image activator it 583 * wants to try first, call it. For example, emulating shell 584 * scripts differently. 585 */ 586 error = -1; 587 if ((img_first = imgp->proc->p_sysent->sv_imgact_try) != NULL) 588 error = img_first(imgp); 589 590 /* 591 * Loop through the list of image activators, calling each one. 592 * An activator returns -1 if there is no match, 0 on success, 593 * and an error otherwise. 594 */ 595 for (i = 0; error == -1 && execsw[i]; ++i) { 596 if (execsw[i]->ex_imgact == NULL || 597 execsw[i]->ex_imgact == img_first) { 598 continue; 599 } 600 error = (*execsw[i]->ex_imgact)(imgp); 601 } 602 603 if (error) { 604 if (error == -1) 605 error = ENOEXEC; 606 goto exec_fail_dealloc; 607 } 608 609 /* 610 * Special interpreter operation, cleanup and loop up to try to 611 * activate the interpreter. 612 */ 613 if (imgp->interpreted) { 614 exec_unmap_first_page(imgp); 615 /* 616 * The text reference needs to be removed for scripts. 617 * There is a short period before we determine that 618 * something is a script where text reference is active. 619 * The vnode lock is held over this entire period 620 * so nothing should illegitimately be blocked. 621 */ 622 MPASS(imgp->textset); 623 VOP_UNSET_TEXT_CHECKED(newtextvp); 624 imgp->textset = false; 625 /* free name buffer and old vnode */ 626 if (args->fname != NULL) 627 NDFREE(&nd, NDF_ONLY_PNBUF); 628 #ifdef MAC 629 mac_execve_interpreter_enter(newtextvp, &interpvplabel); 630 #endif 631 if (imgp->opened) { 632 VOP_CLOSE(newtextvp, FREAD, td->td_ucred, td); 633 imgp->opened = 0; 634 } 635 vput(newtextvp); 636 vm_object_deallocate(imgp->object); 637 imgp->object = NULL; 638 imgp->credential_setid = false; 639 if (imgp->newcred != NULL) { 640 crfree(imgp->newcred); 641 imgp->newcred = NULL; 642 } 643 imgp->execpath = NULL; 644 free(imgp->freepath, M_TEMP); 645 imgp->freepath = NULL; 646 /* set new name to that of the interpreter */ 647 NDINIT(&nd, LOOKUP, ISOPEN | LOCKLEAF | FOLLOW | SAVENAME, 648 UIO_SYSSPACE, imgp->interpreter_name, td); 649 args->fname = imgp->interpreter_name; 650 goto interpret; 651 } 652 653 /* 654 * NB: We unlock the vnode here because it is believed that none 655 * of the sv_copyout_strings/sv_fixup operations require the vnode. 656 */ 657 VOP_UNLOCK(imgp->vp); 658 659 if (disallow_high_osrel && 660 P_OSREL_MAJOR(p->p_osrel) > P_OSREL_MAJOR(__FreeBSD_version)) { 661 error = ENOEXEC; 662 uprintf("Osrel %d for image %s too high\n", p->p_osrel, 663 imgp->execpath != NULL ? imgp->execpath : "<unresolved>"); 664 vn_lock(imgp->vp, LK_SHARED | LK_RETRY); 665 goto exec_fail_dealloc; 666 } 667 668 /* ABI enforces the use of Capsicum. Switch into capabilities mode. */ 669 if (SV_PROC_FLAG(p, SV_CAPSICUM)) 670 sys_cap_enter(td, NULL); 671 672 /* 673 * Copy out strings (args and env) and initialize stack base. 674 */ 675 error = (*p->p_sysent->sv_copyout_strings)(imgp, &stack_base); 676 if (error != 0) { 677 vn_lock(imgp->vp, LK_SHARED | LK_RETRY); 678 goto exec_fail_dealloc; 679 } 680 681 /* 682 * Stack setup. 683 */ 684 error = (*p->p_sysent->sv_fixup)(&stack_base, imgp); 685 if (error != 0) { 686 vn_lock(imgp->vp, LK_SHARED | LK_RETRY); 687 goto exec_fail_dealloc; 688 } 689 690 if (args->fdp != NULL) { 691 /* Install a brand new file descriptor table. */ 692 fdinstall_remapped(td, args->fdp); 693 args->fdp = NULL; 694 } else { 695 /* 696 * Keep on using the existing file descriptor table. For 697 * security and other reasons, the file descriptor table 698 * cannot be shared after an exec. 699 */ 700 fdunshare(td); 701 /* close files on exec */ 702 fdcloseexec(td); 703 } 704 705 /* 706 * Malloc things before we need locks. 707 */ 708 i = exec_args_get_begin_envv(imgp->args) - imgp->args->begin_argv; 709 /* Cache arguments if they fit inside our allowance */ 710 if (ps_arg_cache_limit >= i + sizeof(struct pargs)) { 711 newargs = pargs_alloc(i); 712 bcopy(imgp->args->begin_argv, newargs->ar_args, i); 713 } 714 715 /* 716 * For security and other reasons, signal handlers cannot 717 * be shared after an exec. The new process gets a copy of the old 718 * handlers. In execsigs(), the new process will have its signals 719 * reset. 720 */ 721 if (sigacts_shared(p->p_sigacts)) { 722 oldsigacts = p->p_sigacts; 723 newsigacts = sigacts_alloc(); 724 sigacts_copy(newsigacts, oldsigacts); 725 } 726 727 vn_lock(imgp->vp, LK_SHARED | LK_RETRY); 728 729 PROC_LOCK(p); 730 if (oldsigacts) 731 p->p_sigacts = newsigacts; 732 /* Stop profiling */ 733 stopprofclock(p); 734 735 /* reset caught signals */ 736 execsigs(p); 737 738 /* name this process - nameiexec(p, ndp) */ 739 bzero(p->p_comm, sizeof(p->p_comm)); 740 if (args->fname) 741 bcopy(nd.ni_cnd.cn_nameptr, p->p_comm, 742 min(nd.ni_cnd.cn_namelen, MAXCOMLEN)); 743 else if (vn_commname(newtextvp, p->p_comm, sizeof(p->p_comm)) != 0) 744 bcopy(fexecv_proc_title, p->p_comm, sizeof(fexecv_proc_title)); 745 bcopy(p->p_comm, td->td_name, sizeof(td->td_name)); 746 #ifdef KTR 747 sched_clear_tdname(td); 748 #endif 749 750 /* 751 * mark as execed, wakeup the process that vforked (if any) and tell 752 * it that it now has its own resources back 753 */ 754 p->p_flag |= P_EXEC; 755 if ((p->p_flag2 & P2_NOTRACE_EXEC) == 0) 756 p->p_flag2 &= ~P2_NOTRACE; 757 if ((p->p_flag2 & P2_STKGAP_DISABLE_EXEC) == 0) 758 p->p_flag2 &= ~P2_STKGAP_DISABLE; 759 if (p->p_flag & P_PPWAIT) { 760 p->p_flag &= ~(P_PPWAIT | P_PPTRACE); 761 cv_broadcast(&p->p_pwait); 762 /* STOPs are no longer ignored, arrange for AST */ 763 signotify(td); 764 } 765 766 /* 767 * Implement image setuid/setgid installation. 768 */ 769 if (imgp->credential_setid) { 770 /* 771 * Turn off syscall tracing for set-id programs, except for 772 * root. Record any set-id flags first to make sure that 773 * we do not regain any tracing during a possible block. 774 */ 775 setsugid(p); 776 777 #ifdef KTRACE 778 if (p->p_tracecred != NULL && 779 priv_check_cred(p->p_tracecred, PRIV_DEBUG_DIFFCRED)) 780 ktrprocexec(p, &tracecred, &tracevp); 781 #endif 782 /* 783 * Close any file descriptors 0..2 that reference procfs, 784 * then make sure file descriptors 0..2 are in use. 785 * 786 * Both fdsetugidsafety() and fdcheckstd() may call functions 787 * taking sleepable locks, so temporarily drop our locks. 788 */ 789 PROC_UNLOCK(p); 790 VOP_UNLOCK(imgp->vp); 791 fdsetugidsafety(td); 792 error = fdcheckstd(td); 793 vn_lock(imgp->vp, LK_SHARED | LK_RETRY); 794 if (error != 0) 795 goto exec_fail_dealloc; 796 PROC_LOCK(p); 797 #ifdef MAC 798 if (will_transition) { 799 mac_vnode_execve_transition(oldcred, imgp->newcred, 800 imgp->vp, interpvplabel, imgp); 801 } 802 #endif 803 } else { 804 if (oldcred->cr_uid == oldcred->cr_ruid && 805 oldcred->cr_gid == oldcred->cr_rgid) 806 p->p_flag &= ~P_SUGID; 807 } 808 /* 809 * Set the new credentials. 810 */ 811 if (imgp->newcred != NULL) { 812 proc_set_cred(p, imgp->newcred); 813 crfree(oldcred); 814 oldcred = NULL; 815 } 816 817 /* 818 * Store the vp for use in procfs. This vnode was referenced by namei 819 * or fgetvp_exec. 820 */ 821 oldtextvp = p->p_textvp; 822 p->p_textvp = newtextvp; 823 824 #ifdef KDTRACE_HOOKS 825 /* 826 * Tell the DTrace fasttrap provider about the exec if it 827 * has declared an interest. 828 */ 829 if (dtrace_fasttrap_exec) 830 dtrace_fasttrap_exec(p); 831 #endif 832 833 /* 834 * Notify others that we exec'd, and clear the P_INEXEC flag 835 * as we're now a bona fide freshly-execed process. 836 */ 837 KNOTE_LOCKED(p->p_klist, NOTE_EXEC); 838 p->p_flag &= ~P_INEXEC; 839 840 /* clear "fork but no exec" flag, as we _are_ execing */ 841 p->p_acflag &= ~AFORK; 842 843 /* 844 * Free any previous argument cache and replace it with 845 * the new argument cache, if any. 846 */ 847 oldargs = p->p_args; 848 p->p_args = newargs; 849 newargs = NULL; 850 851 PROC_UNLOCK(p); 852 853 #ifdef HWPMC_HOOKS 854 /* 855 * Check if system-wide sampling is in effect or if the 856 * current process is using PMCs. If so, do exec() time 857 * processing. This processing needs to happen AFTER the 858 * P_INEXEC flag is cleared. 859 */ 860 if (PMC_SYSTEM_SAMPLING_ACTIVE() || PMC_PROC_IS_USING_PMCS(p)) { 861 VOP_UNLOCK(imgp->vp); 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 } 868 #endif 869 870 /* Set values passed into the program in registers. */ 871 (*p->p_sysent->sv_setregs)(td, imgp, stack_base); 872 873 VOP_MMAPPED(imgp->vp); 874 875 SDT_PROBE1(proc, , , exec__success, args->fname); 876 877 exec_fail_dealloc: 878 if (error != 0) { 879 p->p_osrel = orig_osrel; 880 p->p_fctl0 = orig_fctl0; 881 } 882 883 if (imgp->firstpage != NULL) 884 exec_unmap_first_page(imgp); 885 886 if (imgp->vp != NULL) { 887 if (args->fname) 888 NDFREE(&nd, NDF_ONLY_PNBUF); 889 if (imgp->opened) 890 VOP_CLOSE(imgp->vp, FREAD, td->td_ucred, td); 891 if (imgp->textset) 892 VOP_UNSET_TEXT_CHECKED(imgp->vp); 893 if (error != 0) 894 vput(imgp->vp); 895 else 896 VOP_UNLOCK(imgp->vp); 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 if (p->p_ptevents & PTRACE_EXEC) { 906 PROC_LOCK(p); 907 if (p->p_ptevents & PTRACE_EXEC) 908 td->td_dbgflags |= TDB_EXEC; 909 PROC_UNLOCK(p); 910 } 911 912 /* 913 * Stop the process here if its stop event mask has 914 * the S_EXEC bit set. 915 */ 916 STOPEVENT(p, S_EXEC, 0); 917 } else { 918 exec_fail: 919 /* we're done here, clear P_INEXEC */ 920 PROC_LOCK(p); 921 p->p_flag &= ~P_INEXEC; 922 PROC_UNLOCK(p); 923 924 SDT_PROBE1(proc, , , exec__failure, error); 925 } 926 927 if (imgp->newcred != NULL && oldcred != NULL) 928 crfree(imgp->newcred); 929 930 #ifdef MAC 931 mac_execve_exit(imgp); 932 mac_execve_interpreter_exit(interpvplabel); 933 #endif 934 exec_free_args(args); 935 936 /* 937 * Handle deferred decrement of ref counts. 938 */ 939 if (oldtextvp != NULL) 940 vrele(oldtextvp); 941 #ifdef KTRACE 942 if (tracevp != NULL) 943 vrele(tracevp); 944 if (tracecred != NULL) 945 crfree(tracecred); 946 #endif 947 pargs_drop(oldargs); 948 pargs_drop(newargs); 949 if (oldsigacts != NULL) 950 sigacts_free(oldsigacts); 951 if (euip != NULL) 952 uifree(euip); 953 954 if (error && imgp->vmspace_destroyed) { 955 /* sorry, no more process anymore. exit gracefully */ 956 exit1(td, 0, SIGABRT); 957 /* NOT REACHED */ 958 } 959 960 #ifdef KTRACE 961 if (error == 0) 962 ktrprocctor(p); 963 #endif 964 965 /* 966 * We don't want cpu_set_syscall_retval() to overwrite any of 967 * the register values put in place by exec_setregs(). 968 * Implementations of cpu_set_syscall_retval() will leave 969 * registers unmodified when returning EJUSTRETURN. 970 */ 971 return (error == 0 ? EJUSTRETURN : error); 972 } 973 974 int 975 exec_map_first_page(struct image_params *imgp) 976 { 977 vm_object_t object; 978 vm_page_t m; 979 int error; 980 981 if (imgp->firstpage != NULL) 982 exec_unmap_first_page(imgp); 983 984 object = imgp->vp->v_object; 985 if (object == NULL) 986 return (EACCES); 987 VM_OBJECT_WLOCK(object); 988 #if VM_NRESERVLEVEL > 0 989 vm_object_color(object, 0); 990 #endif 991 error = vm_page_grab_valid(&m, object, 0, 992 VM_ALLOC_COUNT(VM_INITIAL_PAGEIN) | 993 VM_ALLOC_NORMAL | VM_ALLOC_NOBUSY | VM_ALLOC_WIRED); 994 VM_OBJECT_WUNLOCK(object); 995 996 if (error != VM_PAGER_OK) 997 return (EIO); 998 imgp->firstpage = sf_buf_alloc(m, 0); 999 imgp->image_header = (char *)sf_buf_kva(imgp->firstpage); 1000 1001 return (0); 1002 } 1003 1004 void 1005 exec_unmap_first_page(struct image_params *imgp) 1006 { 1007 vm_page_t m; 1008 1009 if (imgp->firstpage != NULL) { 1010 m = sf_buf_page(imgp->firstpage); 1011 sf_buf_free(imgp->firstpage); 1012 imgp->firstpage = NULL; 1013 vm_page_unwire(m, PQ_ACTIVE); 1014 } 1015 } 1016 1017 /* 1018 * Destroy old address space, and allocate a new stack. 1019 * The new stack is only sgrowsiz large because it is grown 1020 * automatically on a page fault. 1021 */ 1022 int 1023 exec_new_vmspace(struct image_params *imgp, struct sysentvec *sv) 1024 { 1025 int error; 1026 struct proc *p = imgp->proc; 1027 struct vmspace *vmspace = p->p_vmspace; 1028 vm_object_t obj; 1029 struct rlimit rlim_stack; 1030 vm_offset_t sv_minuser, stack_addr; 1031 vm_map_t map; 1032 u_long ssiz; 1033 1034 imgp->vmspace_destroyed = 1; 1035 imgp->sysent = sv; 1036 1037 /* May be called with Giant held */ 1038 EVENTHANDLER_DIRECT_INVOKE(process_exec, p, imgp); 1039 1040 /* 1041 * Blow away entire process VM, if address space not shared, 1042 * otherwise, create a new VM space so that other threads are 1043 * not disrupted 1044 */ 1045 map = &vmspace->vm_map; 1046 if (map_at_zero) 1047 sv_minuser = sv->sv_minuser; 1048 else 1049 sv_minuser = MAX(sv->sv_minuser, PAGE_SIZE); 1050 if (vmspace->vm_refcnt == 1 && vm_map_min(map) == sv_minuser && 1051 vm_map_max(map) == sv->sv_maxuser && 1052 cpu_exec_vmspace_reuse(p, map)) { 1053 shmexit(vmspace); 1054 pmap_remove_pages(vmspace_pmap(vmspace)); 1055 vm_map_remove(map, vm_map_min(map), vm_map_max(map)); 1056 /* 1057 * An exec terminates mlockall(MCL_FUTURE), ASLR state 1058 * must be re-evaluated. 1059 */ 1060 vm_map_lock(map); 1061 vm_map_modflags(map, 0, MAP_WIREFUTURE | MAP_ASLR | 1062 MAP_ASLR_IGNSTART); 1063 vm_map_unlock(map); 1064 } else { 1065 error = vmspace_exec(p, sv_minuser, sv->sv_maxuser); 1066 if (error) 1067 return (error); 1068 vmspace = p->p_vmspace; 1069 map = &vmspace->vm_map; 1070 } 1071 map->flags |= imgp->map_flags; 1072 1073 /* Map a shared page */ 1074 obj = sv->sv_shared_page_obj; 1075 if (obj != NULL) { 1076 vm_object_reference(obj); 1077 error = vm_map_fixed(map, obj, 0, 1078 sv->sv_shared_page_base, sv->sv_shared_page_len, 1079 VM_PROT_READ | VM_PROT_EXECUTE, 1080 VM_PROT_READ | VM_PROT_EXECUTE, 1081 MAP_INHERIT_SHARE | MAP_ACC_NO_CHARGE); 1082 if (error != KERN_SUCCESS) { 1083 vm_object_deallocate(obj); 1084 return (vm_mmap_to_errno(error)); 1085 } 1086 } 1087 1088 /* Allocate a new stack */ 1089 if (imgp->stack_sz != 0) { 1090 ssiz = trunc_page(imgp->stack_sz); 1091 PROC_LOCK(p); 1092 lim_rlimit_proc(p, RLIMIT_STACK, &rlim_stack); 1093 PROC_UNLOCK(p); 1094 if (ssiz > rlim_stack.rlim_max) 1095 ssiz = rlim_stack.rlim_max; 1096 if (ssiz > rlim_stack.rlim_cur) { 1097 rlim_stack.rlim_cur = ssiz; 1098 kern_setrlimit(curthread, RLIMIT_STACK, &rlim_stack); 1099 } 1100 } else if (sv->sv_maxssiz != NULL) { 1101 ssiz = *sv->sv_maxssiz; 1102 } else { 1103 ssiz = maxssiz; 1104 } 1105 imgp->eff_stack_sz = lim_cur(curthread, RLIMIT_STACK); 1106 if (ssiz < imgp->eff_stack_sz) 1107 imgp->eff_stack_sz = ssiz; 1108 stack_addr = sv->sv_usrstack - ssiz; 1109 error = vm_map_stack(map, stack_addr, (vm_size_t)ssiz, 1110 obj != NULL && imgp->stack_prot != 0 ? imgp->stack_prot : 1111 sv->sv_stackprot, VM_PROT_ALL, MAP_STACK_GROWS_DOWN); 1112 if (error != KERN_SUCCESS) 1113 return (vm_mmap_to_errno(error)); 1114 1115 /* 1116 * vm_ssize and vm_maxsaddr are somewhat antiquated concepts, but they 1117 * are still used to enforce the stack rlimit on the process stack. 1118 */ 1119 vmspace->vm_ssize = sgrowsiz >> PAGE_SHIFT; 1120 vmspace->vm_maxsaddr = (char *)stack_addr; 1121 1122 return (0); 1123 } 1124 1125 /* 1126 * Copy out argument and environment strings from the old process address 1127 * space into the temporary string buffer. 1128 */ 1129 int 1130 exec_copyin_args(struct image_args *args, const char *fname, 1131 enum uio_seg segflg, char **argv, char **envv) 1132 { 1133 u_long arg, env; 1134 int error; 1135 1136 bzero(args, sizeof(*args)); 1137 if (argv == NULL) 1138 return (EFAULT); 1139 1140 /* 1141 * Allocate demand-paged memory for the file name, argument, and 1142 * environment strings. 1143 */ 1144 error = exec_alloc_args(args); 1145 if (error != 0) 1146 return (error); 1147 1148 /* 1149 * Copy the file name. 1150 */ 1151 error = exec_args_add_fname(args, fname, segflg); 1152 if (error != 0) 1153 goto err_exit; 1154 1155 /* 1156 * extract arguments first 1157 */ 1158 for (;;) { 1159 error = fueword(argv++, &arg); 1160 if (error == -1) { 1161 error = EFAULT; 1162 goto err_exit; 1163 } 1164 if (arg == 0) 1165 break; 1166 error = exec_args_add_arg(args, (char *)(uintptr_t)arg, 1167 UIO_USERSPACE); 1168 if (error != 0) 1169 goto err_exit; 1170 } 1171 1172 /* 1173 * extract environment strings 1174 */ 1175 if (envv) { 1176 for (;;) { 1177 error = fueword(envv++, &env); 1178 if (error == -1) { 1179 error = EFAULT; 1180 goto err_exit; 1181 } 1182 if (env == 0) 1183 break; 1184 error = exec_args_add_env(args, 1185 (char *)(uintptr_t)env, UIO_USERSPACE); 1186 if (error != 0) 1187 goto err_exit; 1188 } 1189 } 1190 1191 return (0); 1192 1193 err_exit: 1194 exec_free_args(args); 1195 return (error); 1196 } 1197 1198 int 1199 exec_copyin_data_fds(struct thread *td, struct image_args *args, 1200 const void *data, size_t datalen, const int *fds, size_t fdslen) 1201 { 1202 struct filedesc *ofdp; 1203 const char *p; 1204 int *kfds; 1205 int error; 1206 1207 memset(args, '\0', sizeof(*args)); 1208 ofdp = td->td_proc->p_fd; 1209 if (datalen >= ARG_MAX || fdslen > ofdp->fd_lastfile + 1) 1210 return (E2BIG); 1211 error = exec_alloc_args(args); 1212 if (error != 0) 1213 return (error); 1214 1215 args->begin_argv = args->buf; 1216 args->stringspace = ARG_MAX; 1217 1218 if (datalen > 0) { 1219 /* 1220 * Argument buffer has been provided. Copy it into the 1221 * kernel as a single string and add a terminating null 1222 * byte. 1223 */ 1224 error = copyin(data, args->begin_argv, datalen); 1225 if (error != 0) 1226 goto err_exit; 1227 args->begin_argv[datalen] = '\0'; 1228 args->endp = args->begin_argv + datalen + 1; 1229 args->stringspace -= datalen + 1; 1230 1231 /* 1232 * Traditional argument counting. Count the number of 1233 * null bytes. 1234 */ 1235 for (p = args->begin_argv; p < args->endp; ++p) 1236 if (*p == '\0') 1237 ++args->argc; 1238 } else { 1239 /* No argument buffer provided. */ 1240 args->endp = args->begin_argv; 1241 } 1242 1243 /* Create new file descriptor table. */ 1244 kfds = malloc(fdslen * sizeof(int), M_TEMP, M_WAITOK); 1245 error = copyin(fds, kfds, fdslen * sizeof(int)); 1246 if (error != 0) { 1247 free(kfds, M_TEMP); 1248 goto err_exit; 1249 } 1250 error = fdcopy_remapped(ofdp, kfds, fdslen, &args->fdp); 1251 free(kfds, M_TEMP); 1252 if (error != 0) 1253 goto err_exit; 1254 1255 return (0); 1256 err_exit: 1257 exec_free_args(args); 1258 return (error); 1259 } 1260 1261 struct exec_args_kva { 1262 vm_offset_t addr; 1263 u_int gen; 1264 SLIST_ENTRY(exec_args_kva) next; 1265 }; 1266 1267 DPCPU_DEFINE_STATIC(struct exec_args_kva *, exec_args_kva); 1268 1269 static SLIST_HEAD(, exec_args_kva) exec_args_kva_freelist; 1270 static struct mtx exec_args_kva_mtx; 1271 static u_int exec_args_gen; 1272 1273 static void 1274 exec_prealloc_args_kva(void *arg __unused) 1275 { 1276 struct exec_args_kva *argkva; 1277 u_int i; 1278 1279 SLIST_INIT(&exec_args_kva_freelist); 1280 mtx_init(&exec_args_kva_mtx, "exec args kva", NULL, MTX_DEF); 1281 for (i = 0; i < exec_map_entries; i++) { 1282 argkva = malloc(sizeof(*argkva), M_PARGS, M_WAITOK); 1283 argkva->addr = kmap_alloc_wait(exec_map, exec_map_entry_size); 1284 argkva->gen = exec_args_gen; 1285 SLIST_INSERT_HEAD(&exec_args_kva_freelist, argkva, next); 1286 } 1287 } 1288 SYSINIT(exec_args_kva, SI_SUB_EXEC, SI_ORDER_ANY, exec_prealloc_args_kva, NULL); 1289 1290 static vm_offset_t 1291 exec_alloc_args_kva(void **cookie) 1292 { 1293 struct exec_args_kva *argkva; 1294 1295 argkva = (void *)atomic_readandclear_ptr( 1296 (uintptr_t *)DPCPU_PTR(exec_args_kva)); 1297 if (argkva == NULL) { 1298 mtx_lock(&exec_args_kva_mtx); 1299 while ((argkva = SLIST_FIRST(&exec_args_kva_freelist)) == NULL) 1300 (void)mtx_sleep(&exec_args_kva_freelist, 1301 &exec_args_kva_mtx, 0, "execkva", 0); 1302 SLIST_REMOVE_HEAD(&exec_args_kva_freelist, next); 1303 mtx_unlock(&exec_args_kva_mtx); 1304 } 1305 *(struct exec_args_kva **)cookie = argkva; 1306 return (argkva->addr); 1307 } 1308 1309 static void 1310 exec_release_args_kva(struct exec_args_kva *argkva, u_int gen) 1311 { 1312 vm_offset_t base; 1313 1314 base = argkva->addr; 1315 if (argkva->gen != gen) { 1316 (void)vm_map_madvise(exec_map, base, base + exec_map_entry_size, 1317 MADV_FREE); 1318 argkva->gen = gen; 1319 } 1320 if (!atomic_cmpset_ptr((uintptr_t *)DPCPU_PTR(exec_args_kva), 1321 (uintptr_t)NULL, (uintptr_t)argkva)) { 1322 mtx_lock(&exec_args_kva_mtx); 1323 SLIST_INSERT_HEAD(&exec_args_kva_freelist, argkva, next); 1324 wakeup_one(&exec_args_kva_freelist); 1325 mtx_unlock(&exec_args_kva_mtx); 1326 } 1327 } 1328 1329 static void 1330 exec_free_args_kva(void *cookie) 1331 { 1332 1333 exec_release_args_kva(cookie, exec_args_gen); 1334 } 1335 1336 static void 1337 exec_args_kva_lowmem(void *arg __unused) 1338 { 1339 SLIST_HEAD(, exec_args_kva) head; 1340 struct exec_args_kva *argkva; 1341 u_int gen; 1342 int i; 1343 1344 gen = atomic_fetchadd_int(&exec_args_gen, 1) + 1; 1345 1346 /* 1347 * Force an madvise of each KVA range. Any currently allocated ranges 1348 * will have MADV_FREE applied once they are freed. 1349 */ 1350 SLIST_INIT(&head); 1351 mtx_lock(&exec_args_kva_mtx); 1352 SLIST_SWAP(&head, &exec_args_kva_freelist, exec_args_kva); 1353 mtx_unlock(&exec_args_kva_mtx); 1354 while ((argkva = SLIST_FIRST(&head)) != NULL) { 1355 SLIST_REMOVE_HEAD(&head, next); 1356 exec_release_args_kva(argkva, gen); 1357 } 1358 1359 CPU_FOREACH(i) { 1360 argkva = (void *)atomic_readandclear_ptr( 1361 (uintptr_t *)DPCPU_ID_PTR(i, exec_args_kva)); 1362 if (argkva != NULL) 1363 exec_release_args_kva(argkva, gen); 1364 } 1365 } 1366 EVENTHANDLER_DEFINE(vm_lowmem, exec_args_kva_lowmem, NULL, 1367 EVENTHANDLER_PRI_ANY); 1368 1369 /* 1370 * Allocate temporary demand-paged, zero-filled memory for the file name, 1371 * argument, and environment strings. 1372 */ 1373 int 1374 exec_alloc_args(struct image_args *args) 1375 { 1376 1377 args->buf = (char *)exec_alloc_args_kva(&args->bufkva); 1378 return (0); 1379 } 1380 1381 void 1382 exec_free_args(struct image_args *args) 1383 { 1384 1385 if (args->buf != NULL) { 1386 exec_free_args_kva(args->bufkva); 1387 args->buf = NULL; 1388 } 1389 if (args->fname_buf != NULL) { 1390 free(args->fname_buf, M_TEMP); 1391 args->fname_buf = NULL; 1392 } 1393 if (args->fdp != NULL) 1394 fdescfree_remapped(args->fdp); 1395 } 1396 1397 /* 1398 * A set to functions to fill struct image args. 1399 * 1400 * NOTE: exec_args_add_fname() must be called (possibly with a NULL 1401 * fname) before the other functions. All exec_args_add_arg() calls must 1402 * be made before any exec_args_add_env() calls. exec_args_adjust_args() 1403 * may be called any time after exec_args_add_fname(). 1404 * 1405 * exec_args_add_fname() - install path to be executed 1406 * exec_args_add_arg() - append an argument string 1407 * exec_args_add_env() - append an env string 1408 * exec_args_adjust_args() - adjust location of the argument list to 1409 * allow new arguments to be prepended 1410 */ 1411 int 1412 exec_args_add_fname(struct image_args *args, const char *fname, 1413 enum uio_seg segflg) 1414 { 1415 int error; 1416 size_t length; 1417 1418 KASSERT(args->fname == NULL, ("fname already appended")); 1419 KASSERT(args->endp == NULL, ("already appending to args")); 1420 1421 if (fname != NULL) { 1422 args->fname = args->buf; 1423 error = segflg == UIO_SYSSPACE ? 1424 copystr(fname, args->fname, PATH_MAX, &length) : 1425 copyinstr(fname, args->fname, PATH_MAX, &length); 1426 if (error != 0) 1427 return (error == ENAMETOOLONG ? E2BIG : error); 1428 } else 1429 length = 0; 1430 1431 /* Set up for _arg_*()/_env_*() */ 1432 args->endp = args->buf + length; 1433 /* begin_argv must be set and kept updated */ 1434 args->begin_argv = args->endp; 1435 KASSERT(exec_map_entry_size - length >= ARG_MAX, 1436 ("too little space remaining for arguments %zu < %zu", 1437 exec_map_entry_size - length, (size_t)ARG_MAX)); 1438 args->stringspace = ARG_MAX; 1439 1440 return (0); 1441 } 1442 1443 static int 1444 exec_args_add_str(struct image_args *args, const char *str, 1445 enum uio_seg segflg, int *countp) 1446 { 1447 int error; 1448 size_t length; 1449 1450 KASSERT(args->endp != NULL, ("endp not initialized")); 1451 KASSERT(args->begin_argv != NULL, ("begin_argp not initialized")); 1452 1453 error = (segflg == UIO_SYSSPACE) ? 1454 copystr(str, args->endp, args->stringspace, &length) : 1455 copyinstr(str, args->endp, args->stringspace, &length); 1456 if (error != 0) 1457 return (error == ENAMETOOLONG ? E2BIG : error); 1458 args->stringspace -= length; 1459 args->endp += length; 1460 (*countp)++; 1461 1462 return (0); 1463 } 1464 1465 int 1466 exec_args_add_arg(struct image_args *args, const char *argp, 1467 enum uio_seg segflg) 1468 { 1469 1470 KASSERT(args->envc == 0, ("appending args after env")); 1471 1472 return (exec_args_add_str(args, argp, segflg, &args->argc)); 1473 } 1474 1475 int 1476 exec_args_add_env(struct image_args *args, const char *envp, 1477 enum uio_seg segflg) 1478 { 1479 1480 if (args->envc == 0) 1481 args->begin_envv = args->endp; 1482 1483 return (exec_args_add_str(args, envp, segflg, &args->envc)); 1484 } 1485 1486 int 1487 exec_args_adjust_args(struct image_args *args, size_t consume, ssize_t extend) 1488 { 1489 ssize_t offset; 1490 1491 KASSERT(args->endp != NULL, ("endp not initialized")); 1492 KASSERT(args->begin_argv != NULL, ("begin_argp not initialized")); 1493 1494 offset = extend - consume; 1495 if (args->stringspace < offset) 1496 return (E2BIG); 1497 memmove(args->begin_argv + extend, args->begin_argv + consume, 1498 args->endp - args->begin_argv + consume); 1499 if (args->envc > 0) 1500 args->begin_envv += offset; 1501 args->endp += offset; 1502 args->stringspace -= offset; 1503 return (0); 1504 } 1505 1506 char * 1507 exec_args_get_begin_envv(struct image_args *args) 1508 { 1509 1510 KASSERT(args->endp != NULL, ("endp not initialized")); 1511 1512 if (args->envc > 0) 1513 return (args->begin_envv); 1514 return (args->endp); 1515 } 1516 1517 /* 1518 * Copy strings out to the new process address space, constructing new arg 1519 * and env vector tables. Return a pointer to the base so that it can be used 1520 * as the initial stack pointer. 1521 */ 1522 int 1523 exec_copyout_strings(struct image_params *imgp, uintptr_t *stack_base) 1524 { 1525 int argc, envc; 1526 char **vectp; 1527 char *stringp; 1528 uintptr_t destp, ustringp; 1529 struct ps_strings *arginfo; 1530 struct proc *p; 1531 size_t execpath_len; 1532 int error, szsigcode, szps; 1533 char canary[sizeof(long) * 8]; 1534 1535 szps = sizeof(pagesizes[0]) * MAXPAGESIZES; 1536 /* 1537 * Calculate string base and vector table pointers. 1538 * Also deal with signal trampoline code for this exec type. 1539 */ 1540 if (imgp->execpath != NULL && imgp->auxargs != NULL) 1541 execpath_len = strlen(imgp->execpath) + 1; 1542 else 1543 execpath_len = 0; 1544 p = imgp->proc; 1545 szsigcode = 0; 1546 arginfo = (struct ps_strings *)p->p_sysent->sv_psstrings; 1547 if (p->p_sysent->sv_sigcode_base == 0) { 1548 if (p->p_sysent->sv_szsigcode != NULL) 1549 szsigcode = *(p->p_sysent->sv_szsigcode); 1550 } 1551 destp = (uintptr_t)arginfo; 1552 1553 /* 1554 * install sigcode 1555 */ 1556 if (szsigcode != 0) { 1557 destp -= szsigcode; 1558 destp = rounddown2(destp, sizeof(void *)); 1559 error = copyout(p->p_sysent->sv_sigcode, (void *)destp, 1560 szsigcode); 1561 if (error != 0) 1562 return (error); 1563 } 1564 1565 /* 1566 * Copy the image path for the rtld. 1567 */ 1568 if (execpath_len != 0) { 1569 destp -= execpath_len; 1570 destp = rounddown2(destp, sizeof(void *)); 1571 imgp->execpathp = destp; 1572 error = copyout(imgp->execpath, (void *)destp, execpath_len); 1573 if (error != 0) 1574 return (error); 1575 } 1576 1577 /* 1578 * Prepare the canary for SSP. 1579 */ 1580 arc4rand(canary, sizeof(canary), 0); 1581 destp -= sizeof(canary); 1582 imgp->canary = destp; 1583 error = copyout(canary, (void *)destp, sizeof(canary)); 1584 if (error != 0) 1585 return (error); 1586 imgp->canarylen = sizeof(canary); 1587 1588 /* 1589 * Prepare the pagesizes array. 1590 */ 1591 destp -= szps; 1592 destp = rounddown2(destp, sizeof(void *)); 1593 imgp->pagesizes = destp; 1594 error = copyout(pagesizes, (void *)destp, szps); 1595 if (error != 0) 1596 return (error); 1597 imgp->pagesizeslen = szps; 1598 1599 /* 1600 * Allocate room for the argument and environment strings. 1601 */ 1602 destp -= ARG_MAX - imgp->args->stringspace; 1603 destp = rounddown2(destp, sizeof(void *)); 1604 ustringp = destp; 1605 1606 if (imgp->sysent->sv_stackgap != NULL) 1607 imgp->sysent->sv_stackgap(imgp, &destp); 1608 1609 if (imgp->auxargs) { 1610 /* 1611 * Allocate room on the stack for the ELF auxargs 1612 * array. It has up to AT_COUNT entries. 1613 */ 1614 destp -= AT_COUNT * sizeof(Elf_Auxinfo); 1615 destp = rounddown2(destp, sizeof(void *)); 1616 } 1617 1618 vectp = (char **)destp; 1619 1620 /* 1621 * Allocate room for the argv[] and env vectors including the 1622 * terminating NULL pointers. 1623 */ 1624 vectp -= imgp->args->argc + 1 + imgp->args->envc + 1; 1625 1626 /* 1627 * vectp also becomes our initial stack base 1628 */ 1629 *stack_base = (uintptr_t)vectp; 1630 1631 stringp = imgp->args->begin_argv; 1632 argc = imgp->args->argc; 1633 envc = imgp->args->envc; 1634 1635 /* 1636 * Copy out strings - arguments and environment. 1637 */ 1638 error = copyout(stringp, (void *)ustringp, 1639 ARG_MAX - imgp->args->stringspace); 1640 if (error != 0) 1641 return (error); 1642 1643 /* 1644 * Fill in "ps_strings" struct for ps, w, etc. 1645 */ 1646 if (suword(&arginfo->ps_argvstr, (long)(intptr_t)vectp) != 0 || 1647 suword32(&arginfo->ps_nargvstr, argc) != 0) 1648 return (EFAULT); 1649 1650 /* 1651 * Fill in argument portion of vector table. 1652 */ 1653 for (; argc > 0; --argc) { 1654 if (suword(vectp++, ustringp) != 0) 1655 return (EFAULT); 1656 while (*stringp++ != 0) 1657 ustringp++; 1658 ustringp++; 1659 } 1660 1661 /* a null vector table pointer separates the argp's from the envp's */ 1662 if (suword(vectp++, 0) != 0) 1663 return (EFAULT); 1664 1665 if (suword(&arginfo->ps_envstr, (long)(intptr_t)vectp) != 0 || 1666 suword32(&arginfo->ps_nenvstr, envc) != 0) 1667 return (EFAULT); 1668 1669 /* 1670 * Fill in environment portion of vector table. 1671 */ 1672 for (; envc > 0; --envc) { 1673 if (suword(vectp++, ustringp) != 0) 1674 return (EFAULT); 1675 while (*stringp++ != 0) 1676 ustringp++; 1677 ustringp++; 1678 } 1679 1680 /* end of vector table is a null pointer */ 1681 if (suword(vectp, 0) != 0) 1682 return (EFAULT); 1683 1684 if (imgp->auxargs) { 1685 vectp++; 1686 error = imgp->sysent->sv_copyout_auxargs(imgp, 1687 (uintptr_t)vectp); 1688 if (error != 0) 1689 return (error); 1690 } 1691 1692 return (0); 1693 } 1694 1695 /* 1696 * Check permissions of file to execute. 1697 * Called with imgp->vp locked. 1698 * Return 0 for success or error code on failure. 1699 */ 1700 int 1701 exec_check_permissions(struct image_params *imgp) 1702 { 1703 struct vnode *vp = imgp->vp; 1704 struct vattr *attr = imgp->attr; 1705 struct thread *td; 1706 int error; 1707 1708 td = curthread; 1709 1710 /* Get file attributes */ 1711 error = VOP_GETATTR(vp, attr, td->td_ucred); 1712 if (error) 1713 return (error); 1714 1715 #ifdef MAC 1716 error = mac_vnode_check_exec(td->td_ucred, imgp->vp, imgp); 1717 if (error) 1718 return (error); 1719 #endif 1720 1721 /* 1722 * 1) Check if file execution is disabled for the filesystem that 1723 * this file resides on. 1724 * 2) Ensure that at least one execute bit is on. Otherwise, a 1725 * privileged user will always succeed, and we don't want this 1726 * to happen unless the file really is executable. 1727 * 3) Ensure that the file is a regular file. 1728 */ 1729 if ((vp->v_mount->mnt_flag & MNT_NOEXEC) || 1730 (attr->va_mode & (S_IXUSR | S_IXGRP | S_IXOTH)) == 0 || 1731 (attr->va_type != VREG)) 1732 return (EACCES); 1733 1734 /* 1735 * Zero length files can't be exec'd 1736 */ 1737 if (attr->va_size == 0) 1738 return (ENOEXEC); 1739 1740 /* 1741 * Check for execute permission to file based on current credentials. 1742 */ 1743 error = VOP_ACCESS(vp, VEXEC, td->td_ucred, td); 1744 if (error) 1745 return (error); 1746 1747 /* 1748 * Check number of open-for-writes on the file and deny execution 1749 * if there are any. 1750 * 1751 * Add a text reference now so no one can write to the 1752 * executable while we're activating it. 1753 * 1754 * Remember if this was set before and unset it in case this is not 1755 * actually an executable image. 1756 */ 1757 error = VOP_SET_TEXT(vp); 1758 if (error != 0) 1759 return (error); 1760 imgp->textset = true; 1761 1762 /* 1763 * Call filesystem specific open routine (which does nothing in the 1764 * general case). 1765 */ 1766 error = VOP_OPEN(vp, FREAD, td->td_ucred, td, NULL); 1767 if (error == 0) 1768 imgp->opened = 1; 1769 return (error); 1770 } 1771 1772 /* 1773 * Exec handler registration 1774 */ 1775 int 1776 exec_register(const struct execsw *execsw_arg) 1777 { 1778 const struct execsw **es, **xs, **newexecsw; 1779 u_int count = 2; /* New slot and trailing NULL */ 1780 1781 if (execsw) 1782 for (es = execsw; *es; es++) 1783 count++; 1784 newexecsw = malloc(count * sizeof(*es), M_TEMP, M_WAITOK); 1785 xs = newexecsw; 1786 if (execsw) 1787 for (es = execsw; *es; es++) 1788 *xs++ = *es; 1789 *xs++ = execsw_arg; 1790 *xs = NULL; 1791 if (execsw) 1792 free(execsw, M_TEMP); 1793 execsw = newexecsw; 1794 return (0); 1795 } 1796 1797 int 1798 exec_unregister(const struct execsw *execsw_arg) 1799 { 1800 const struct execsw **es, **xs, **newexecsw; 1801 int count = 1; 1802 1803 if (execsw == NULL) 1804 panic("unregister with no handlers left?\n"); 1805 1806 for (es = execsw; *es; es++) { 1807 if (*es == execsw_arg) 1808 break; 1809 } 1810 if (*es == NULL) 1811 return (ENOENT); 1812 for (es = execsw; *es; es++) 1813 if (*es != execsw_arg) 1814 count++; 1815 newexecsw = malloc(count * sizeof(*es), M_TEMP, M_WAITOK); 1816 xs = newexecsw; 1817 for (es = execsw; *es; es++) 1818 if (*es != execsw_arg) 1819 *xs++ = *es; 1820 *xs = NULL; 1821 if (execsw) 1822 free(execsw, M_TEMP); 1823 execsw = newexecsw; 1824 return (0); 1825 } 1826