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, 0); 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, 0); 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, 0); 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, 0); 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, 0); 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, 0); 862 pe.pm_credentialschanged = credential_changing; 863 pe.pm_entryaddr = imgp->entry_addr; 864 865 PMC_CALL_HOOK_X(td, PMC_FN_PROCESS_EXEC, (void *) &pe); 866 vn_lock(imgp->vp, LK_SHARED | LK_RETRY); 867 } 868 #endif 869 870 /* Set values passed into the program in registers. */ 871 (*p->p_sysent->sv_setregs)(td, imgp, stack_base); 872 873 vfs_mark_atime(imgp->vp, td->td_ucred); 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, 0); 897 } 898 899 if (imgp->object != NULL) 900 vm_object_deallocate(imgp->object); 901 902 free(imgp->freepath, M_TEMP); 903 904 if (error == 0) { 905 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 int rv, i, after, initial_pagein; 978 vm_page_t ma[VM_INITIAL_PAGEIN]; 979 vm_object_t object; 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 retry: 992 ma[0] = vm_page_grab(object, 0, VM_ALLOC_NORMAL | VM_ALLOC_NOBUSY | 993 VM_ALLOC_WIRED); 994 if (!vm_page_all_valid(ma[0])) { 995 if (vm_page_busy_acquire(ma[0], VM_ALLOC_WAITFAIL) == 0) { 996 vm_page_unwire_noq(ma[0]); 997 goto retry; 998 } 999 if (vm_page_all_valid(ma[0])) { 1000 vm_page_xunbusy(ma[0]); 1001 goto out; 1002 } 1003 if (!vm_pager_has_page(object, 0, NULL, &after)) { 1004 if (vm_page_unwire_noq(ma[0])) 1005 vm_page_free(ma[0]); 1006 else 1007 vm_page_xunbusy(ma[0]); 1008 VM_OBJECT_WUNLOCK(object); 1009 return (EIO); 1010 } 1011 initial_pagein = min(after, VM_INITIAL_PAGEIN); 1012 KASSERT(initial_pagein <= object->size, 1013 ("%s: initial_pagein %d object->size %ju", 1014 __func__, initial_pagein, (uintmax_t )object->size)); 1015 for (i = 1; i < initial_pagein; i++) { 1016 if ((ma[i] = vm_page_next(ma[i - 1])) != NULL) { 1017 if (ma[i]->valid) 1018 break; 1019 if (!vm_page_tryxbusy(ma[i])) 1020 break; 1021 } else { 1022 ma[i] = vm_page_alloc(object, i, 1023 VM_ALLOC_NORMAL); 1024 if (ma[i] == NULL) 1025 break; 1026 } 1027 } 1028 initial_pagein = i; 1029 rv = vm_pager_get_pages(object, ma, initial_pagein, NULL, NULL); 1030 if (rv != VM_PAGER_OK) { 1031 if (vm_page_unwire_noq(ma[0])) 1032 vm_page_free(ma[0]); 1033 else 1034 vm_page_xunbusy(ma[0]); 1035 for (i = 1; i < initial_pagein; i++) { 1036 if (!vm_page_wired(ma[i])) 1037 vm_page_free(ma[i]); 1038 else 1039 vm_page_xunbusy(ma[i]); 1040 } 1041 VM_OBJECT_WUNLOCK(object); 1042 return (EIO); 1043 } 1044 vm_page_xunbusy(ma[0]); 1045 for (i = 1; i < initial_pagein; i++) 1046 vm_page_readahead_finish(ma[i]); 1047 } 1048 1049 out: 1050 VM_OBJECT_WUNLOCK(object); 1051 1052 imgp->firstpage = sf_buf_alloc(ma[0], 0); 1053 imgp->image_header = (char *)sf_buf_kva(imgp->firstpage); 1054 1055 return (0); 1056 } 1057 1058 void 1059 exec_unmap_first_page(struct image_params *imgp) 1060 { 1061 vm_page_t m; 1062 1063 if (imgp->firstpage != NULL) { 1064 m = sf_buf_page(imgp->firstpage); 1065 sf_buf_free(imgp->firstpage); 1066 imgp->firstpage = NULL; 1067 vm_page_unwire(m, PQ_ACTIVE); 1068 } 1069 } 1070 1071 /* 1072 * Destroy old address space, and allocate a new stack. 1073 * The new stack is only sgrowsiz large because it is grown 1074 * automatically on a page fault. 1075 */ 1076 int 1077 exec_new_vmspace(struct image_params *imgp, struct sysentvec *sv) 1078 { 1079 int error; 1080 struct proc *p = imgp->proc; 1081 struct vmspace *vmspace = p->p_vmspace; 1082 vm_object_t obj; 1083 struct rlimit rlim_stack; 1084 vm_offset_t sv_minuser, stack_addr; 1085 vm_map_t map; 1086 u_long ssiz; 1087 1088 imgp->vmspace_destroyed = 1; 1089 imgp->sysent = sv; 1090 1091 /* May be called with Giant held */ 1092 EVENTHANDLER_DIRECT_INVOKE(process_exec, p, imgp); 1093 1094 /* 1095 * Blow away entire process VM, if address space not shared, 1096 * otherwise, create a new VM space so that other threads are 1097 * not disrupted 1098 */ 1099 map = &vmspace->vm_map; 1100 if (map_at_zero) 1101 sv_minuser = sv->sv_minuser; 1102 else 1103 sv_minuser = MAX(sv->sv_minuser, PAGE_SIZE); 1104 if (vmspace->vm_refcnt == 1 && vm_map_min(map) == sv_minuser && 1105 vm_map_max(map) == sv->sv_maxuser && 1106 cpu_exec_vmspace_reuse(p, map)) { 1107 shmexit(vmspace); 1108 pmap_remove_pages(vmspace_pmap(vmspace)); 1109 vm_map_remove(map, vm_map_min(map), vm_map_max(map)); 1110 /* 1111 * An exec terminates mlockall(MCL_FUTURE), ASLR state 1112 * must be re-evaluated. 1113 */ 1114 vm_map_lock(map); 1115 vm_map_modflags(map, 0, MAP_WIREFUTURE | MAP_ASLR | 1116 MAP_ASLR_IGNSTART); 1117 vm_map_unlock(map); 1118 } else { 1119 error = vmspace_exec(p, sv_minuser, sv->sv_maxuser); 1120 if (error) 1121 return (error); 1122 vmspace = p->p_vmspace; 1123 map = &vmspace->vm_map; 1124 } 1125 map->flags |= imgp->map_flags; 1126 1127 /* Map a shared page */ 1128 obj = sv->sv_shared_page_obj; 1129 if (obj != NULL) { 1130 vm_object_reference(obj); 1131 error = vm_map_fixed(map, obj, 0, 1132 sv->sv_shared_page_base, sv->sv_shared_page_len, 1133 VM_PROT_READ | VM_PROT_EXECUTE, 1134 VM_PROT_READ | VM_PROT_EXECUTE, 1135 MAP_INHERIT_SHARE | MAP_ACC_NO_CHARGE); 1136 if (error != KERN_SUCCESS) { 1137 vm_object_deallocate(obj); 1138 return (vm_mmap_to_errno(error)); 1139 } 1140 } 1141 1142 /* Allocate a new stack */ 1143 if (imgp->stack_sz != 0) { 1144 ssiz = trunc_page(imgp->stack_sz); 1145 PROC_LOCK(p); 1146 lim_rlimit_proc(p, RLIMIT_STACK, &rlim_stack); 1147 PROC_UNLOCK(p); 1148 if (ssiz > rlim_stack.rlim_max) 1149 ssiz = rlim_stack.rlim_max; 1150 if (ssiz > rlim_stack.rlim_cur) { 1151 rlim_stack.rlim_cur = ssiz; 1152 kern_setrlimit(curthread, RLIMIT_STACK, &rlim_stack); 1153 } 1154 } else if (sv->sv_maxssiz != NULL) { 1155 ssiz = *sv->sv_maxssiz; 1156 } else { 1157 ssiz = maxssiz; 1158 } 1159 imgp->eff_stack_sz = lim_cur(curthread, RLIMIT_STACK); 1160 if (ssiz < imgp->eff_stack_sz) 1161 imgp->eff_stack_sz = ssiz; 1162 stack_addr = sv->sv_usrstack - ssiz; 1163 error = vm_map_stack(map, stack_addr, (vm_size_t)ssiz, 1164 obj != NULL && imgp->stack_prot != 0 ? imgp->stack_prot : 1165 sv->sv_stackprot, VM_PROT_ALL, MAP_STACK_GROWS_DOWN); 1166 if (error != KERN_SUCCESS) 1167 return (vm_mmap_to_errno(error)); 1168 1169 /* 1170 * vm_ssize and vm_maxsaddr are somewhat antiquated concepts, but they 1171 * are still used to enforce the stack rlimit on the process stack. 1172 */ 1173 vmspace->vm_ssize = sgrowsiz >> PAGE_SHIFT; 1174 vmspace->vm_maxsaddr = (char *)stack_addr; 1175 1176 return (0); 1177 } 1178 1179 /* 1180 * Copy out argument and environment strings from the old process address 1181 * space into the temporary string buffer. 1182 */ 1183 int 1184 exec_copyin_args(struct image_args *args, const char *fname, 1185 enum uio_seg segflg, char **argv, char **envv) 1186 { 1187 u_long arg, env; 1188 int error; 1189 1190 bzero(args, sizeof(*args)); 1191 if (argv == NULL) 1192 return (EFAULT); 1193 1194 /* 1195 * Allocate demand-paged memory for the file name, argument, and 1196 * environment strings. 1197 */ 1198 error = exec_alloc_args(args); 1199 if (error != 0) 1200 return (error); 1201 1202 /* 1203 * Copy the file name. 1204 */ 1205 error = exec_args_add_fname(args, fname, segflg); 1206 if (error != 0) 1207 goto err_exit; 1208 1209 /* 1210 * extract arguments first 1211 */ 1212 for (;;) { 1213 error = fueword(argv++, &arg); 1214 if (error == -1) { 1215 error = EFAULT; 1216 goto err_exit; 1217 } 1218 if (arg == 0) 1219 break; 1220 error = exec_args_add_arg(args, (char *)(uintptr_t)arg, 1221 UIO_USERSPACE); 1222 if (error != 0) 1223 goto err_exit; 1224 } 1225 1226 /* 1227 * extract environment strings 1228 */ 1229 if (envv) { 1230 for (;;) { 1231 error = fueword(envv++, &env); 1232 if (error == -1) { 1233 error = EFAULT; 1234 goto err_exit; 1235 } 1236 if (env == 0) 1237 break; 1238 error = exec_args_add_env(args, 1239 (char *)(uintptr_t)env, UIO_USERSPACE); 1240 if (error != 0) 1241 goto err_exit; 1242 } 1243 } 1244 1245 return (0); 1246 1247 err_exit: 1248 exec_free_args(args); 1249 return (error); 1250 } 1251 1252 int 1253 exec_copyin_data_fds(struct thread *td, struct image_args *args, 1254 const void *data, size_t datalen, const int *fds, size_t fdslen) 1255 { 1256 struct filedesc *ofdp; 1257 const char *p; 1258 int *kfds; 1259 int error; 1260 1261 memset(args, '\0', sizeof(*args)); 1262 ofdp = td->td_proc->p_fd; 1263 if (datalen >= ARG_MAX || fdslen > ofdp->fd_lastfile + 1) 1264 return (E2BIG); 1265 error = exec_alloc_args(args); 1266 if (error != 0) 1267 return (error); 1268 1269 args->begin_argv = args->buf; 1270 args->stringspace = ARG_MAX; 1271 1272 if (datalen > 0) { 1273 /* 1274 * Argument buffer has been provided. Copy it into the 1275 * kernel as a single string and add a terminating null 1276 * byte. 1277 */ 1278 error = copyin(data, args->begin_argv, datalen); 1279 if (error != 0) 1280 goto err_exit; 1281 args->begin_argv[datalen] = '\0'; 1282 args->endp = args->begin_argv + datalen + 1; 1283 args->stringspace -= datalen + 1; 1284 1285 /* 1286 * Traditional argument counting. Count the number of 1287 * null bytes. 1288 */ 1289 for (p = args->begin_argv; p < args->endp; ++p) 1290 if (*p == '\0') 1291 ++args->argc; 1292 } else { 1293 /* No argument buffer provided. */ 1294 args->endp = args->begin_argv; 1295 } 1296 1297 /* Create new file descriptor table. */ 1298 kfds = malloc(fdslen * sizeof(int), M_TEMP, M_WAITOK); 1299 error = copyin(fds, kfds, fdslen * sizeof(int)); 1300 if (error != 0) { 1301 free(kfds, M_TEMP); 1302 goto err_exit; 1303 } 1304 error = fdcopy_remapped(ofdp, kfds, fdslen, &args->fdp); 1305 free(kfds, M_TEMP); 1306 if (error != 0) 1307 goto err_exit; 1308 1309 return (0); 1310 err_exit: 1311 exec_free_args(args); 1312 return (error); 1313 } 1314 1315 struct exec_args_kva { 1316 vm_offset_t addr; 1317 u_int gen; 1318 SLIST_ENTRY(exec_args_kva) next; 1319 }; 1320 1321 DPCPU_DEFINE_STATIC(struct exec_args_kva *, exec_args_kva); 1322 1323 static SLIST_HEAD(, exec_args_kva) exec_args_kva_freelist; 1324 static struct mtx exec_args_kva_mtx; 1325 static u_int exec_args_gen; 1326 1327 static void 1328 exec_prealloc_args_kva(void *arg __unused) 1329 { 1330 struct exec_args_kva *argkva; 1331 u_int i; 1332 1333 SLIST_INIT(&exec_args_kva_freelist); 1334 mtx_init(&exec_args_kva_mtx, "exec args kva", NULL, MTX_DEF); 1335 for (i = 0; i < exec_map_entries; i++) { 1336 argkva = malloc(sizeof(*argkva), M_PARGS, M_WAITOK); 1337 argkva->addr = kmap_alloc_wait(exec_map, exec_map_entry_size); 1338 argkva->gen = exec_args_gen; 1339 SLIST_INSERT_HEAD(&exec_args_kva_freelist, argkva, next); 1340 } 1341 } 1342 SYSINIT(exec_args_kva, SI_SUB_EXEC, SI_ORDER_ANY, exec_prealloc_args_kva, NULL); 1343 1344 static vm_offset_t 1345 exec_alloc_args_kva(void **cookie) 1346 { 1347 struct exec_args_kva *argkva; 1348 1349 argkva = (void *)atomic_readandclear_ptr( 1350 (uintptr_t *)DPCPU_PTR(exec_args_kva)); 1351 if (argkva == NULL) { 1352 mtx_lock(&exec_args_kva_mtx); 1353 while ((argkva = SLIST_FIRST(&exec_args_kva_freelist)) == NULL) 1354 (void)mtx_sleep(&exec_args_kva_freelist, 1355 &exec_args_kva_mtx, 0, "execkva", 0); 1356 SLIST_REMOVE_HEAD(&exec_args_kva_freelist, next); 1357 mtx_unlock(&exec_args_kva_mtx); 1358 } 1359 *(struct exec_args_kva **)cookie = argkva; 1360 return (argkva->addr); 1361 } 1362 1363 static void 1364 exec_release_args_kva(struct exec_args_kva *argkva, u_int gen) 1365 { 1366 vm_offset_t base; 1367 1368 base = argkva->addr; 1369 if (argkva->gen != gen) { 1370 (void)vm_map_madvise(exec_map, base, base + exec_map_entry_size, 1371 MADV_FREE); 1372 argkva->gen = gen; 1373 } 1374 if (!atomic_cmpset_ptr((uintptr_t *)DPCPU_PTR(exec_args_kva), 1375 (uintptr_t)NULL, (uintptr_t)argkva)) { 1376 mtx_lock(&exec_args_kva_mtx); 1377 SLIST_INSERT_HEAD(&exec_args_kva_freelist, argkva, next); 1378 wakeup_one(&exec_args_kva_freelist); 1379 mtx_unlock(&exec_args_kva_mtx); 1380 } 1381 } 1382 1383 static void 1384 exec_free_args_kva(void *cookie) 1385 { 1386 1387 exec_release_args_kva(cookie, exec_args_gen); 1388 } 1389 1390 static void 1391 exec_args_kva_lowmem(void *arg __unused) 1392 { 1393 SLIST_HEAD(, exec_args_kva) head; 1394 struct exec_args_kva *argkva; 1395 u_int gen; 1396 int i; 1397 1398 gen = atomic_fetchadd_int(&exec_args_gen, 1) + 1; 1399 1400 /* 1401 * Force an madvise of each KVA range. Any currently allocated ranges 1402 * will have MADV_FREE applied once they are freed. 1403 */ 1404 SLIST_INIT(&head); 1405 mtx_lock(&exec_args_kva_mtx); 1406 SLIST_SWAP(&head, &exec_args_kva_freelist, exec_args_kva); 1407 mtx_unlock(&exec_args_kva_mtx); 1408 while ((argkva = SLIST_FIRST(&head)) != NULL) { 1409 SLIST_REMOVE_HEAD(&head, next); 1410 exec_release_args_kva(argkva, gen); 1411 } 1412 1413 CPU_FOREACH(i) { 1414 argkva = (void *)atomic_readandclear_ptr( 1415 (uintptr_t *)DPCPU_ID_PTR(i, exec_args_kva)); 1416 if (argkva != NULL) 1417 exec_release_args_kva(argkva, gen); 1418 } 1419 } 1420 EVENTHANDLER_DEFINE(vm_lowmem, exec_args_kva_lowmem, NULL, 1421 EVENTHANDLER_PRI_ANY); 1422 1423 /* 1424 * Allocate temporary demand-paged, zero-filled memory for the file name, 1425 * argument, and environment strings. 1426 */ 1427 int 1428 exec_alloc_args(struct image_args *args) 1429 { 1430 1431 args->buf = (char *)exec_alloc_args_kva(&args->bufkva); 1432 return (0); 1433 } 1434 1435 void 1436 exec_free_args(struct image_args *args) 1437 { 1438 1439 if (args->buf != NULL) { 1440 exec_free_args_kva(args->bufkva); 1441 args->buf = NULL; 1442 } 1443 if (args->fname_buf != NULL) { 1444 free(args->fname_buf, M_TEMP); 1445 args->fname_buf = NULL; 1446 } 1447 if (args->fdp != NULL) 1448 fdescfree_remapped(args->fdp); 1449 } 1450 1451 /* 1452 * A set to functions to fill struct image args. 1453 * 1454 * NOTE: exec_args_add_fname() must be called (possibly with a NULL 1455 * fname) before the other functions. All exec_args_add_arg() calls must 1456 * be made before any exec_args_add_env() calls. exec_args_adjust_args() 1457 * may be called any time after exec_args_add_fname(). 1458 * 1459 * exec_args_add_fname() - install path to be executed 1460 * exec_args_add_arg() - append an argument string 1461 * exec_args_add_env() - append an env string 1462 * exec_args_adjust_args() - adjust location of the argument list to 1463 * allow new arguments to be prepended 1464 */ 1465 int 1466 exec_args_add_fname(struct image_args *args, const char *fname, 1467 enum uio_seg segflg) 1468 { 1469 int error; 1470 size_t length; 1471 1472 KASSERT(args->fname == NULL, ("fname already appended")); 1473 KASSERT(args->endp == NULL, ("already appending to args")); 1474 1475 if (fname != NULL) { 1476 args->fname = args->buf; 1477 error = segflg == UIO_SYSSPACE ? 1478 copystr(fname, args->fname, PATH_MAX, &length) : 1479 copyinstr(fname, args->fname, PATH_MAX, &length); 1480 if (error != 0) 1481 return (error == ENAMETOOLONG ? E2BIG : error); 1482 } else 1483 length = 0; 1484 1485 /* Set up for _arg_*()/_env_*() */ 1486 args->endp = args->buf + length; 1487 /* begin_argv must be set and kept updated */ 1488 args->begin_argv = args->endp; 1489 KASSERT(exec_map_entry_size - length >= ARG_MAX, 1490 ("too little space remaining for arguments %zu < %zu", 1491 exec_map_entry_size - length, (size_t)ARG_MAX)); 1492 args->stringspace = ARG_MAX; 1493 1494 return (0); 1495 } 1496 1497 static int 1498 exec_args_add_str(struct image_args *args, const char *str, 1499 enum uio_seg segflg, int *countp) 1500 { 1501 int error; 1502 size_t length; 1503 1504 KASSERT(args->endp != NULL, ("endp not initialized")); 1505 KASSERT(args->begin_argv != NULL, ("begin_argp not initialized")); 1506 1507 error = (segflg == UIO_SYSSPACE) ? 1508 copystr(str, args->endp, args->stringspace, &length) : 1509 copyinstr(str, args->endp, args->stringspace, &length); 1510 if (error != 0) 1511 return (error == ENAMETOOLONG ? E2BIG : error); 1512 args->stringspace -= length; 1513 args->endp += length; 1514 (*countp)++; 1515 1516 return (0); 1517 } 1518 1519 int 1520 exec_args_add_arg(struct image_args *args, const char *argp, 1521 enum uio_seg segflg) 1522 { 1523 1524 KASSERT(args->envc == 0, ("appending args after env")); 1525 1526 return (exec_args_add_str(args, argp, segflg, &args->argc)); 1527 } 1528 1529 int 1530 exec_args_add_env(struct image_args *args, const char *envp, 1531 enum uio_seg segflg) 1532 { 1533 1534 if (args->envc == 0) 1535 args->begin_envv = args->endp; 1536 1537 return (exec_args_add_str(args, envp, segflg, &args->envc)); 1538 } 1539 1540 int 1541 exec_args_adjust_args(struct image_args *args, size_t consume, ssize_t extend) 1542 { 1543 ssize_t offset; 1544 1545 KASSERT(args->endp != NULL, ("endp not initialized")); 1546 KASSERT(args->begin_argv != NULL, ("begin_argp not initialized")); 1547 1548 offset = extend - consume; 1549 if (args->stringspace < offset) 1550 return (E2BIG); 1551 memmove(args->begin_argv + extend, args->begin_argv + consume, 1552 args->endp - args->begin_argv + consume); 1553 if (args->envc > 0) 1554 args->begin_envv += offset; 1555 args->endp += offset; 1556 args->stringspace -= offset; 1557 return (0); 1558 } 1559 1560 char * 1561 exec_args_get_begin_envv(struct image_args *args) 1562 { 1563 1564 KASSERT(args->endp != NULL, ("endp not initialized")); 1565 1566 if (args->envc > 0) 1567 return (args->begin_envv); 1568 return (args->endp); 1569 } 1570 1571 /* 1572 * Copy strings out to the new process address space, constructing new arg 1573 * and env vector tables. Return a pointer to the base so that it can be used 1574 * as the initial stack pointer. 1575 */ 1576 int 1577 exec_copyout_strings(struct image_params *imgp, uintptr_t *stack_base) 1578 { 1579 int argc, envc; 1580 char **vectp; 1581 char *stringp; 1582 uintptr_t destp, ustringp; 1583 struct ps_strings *arginfo; 1584 struct proc *p; 1585 size_t execpath_len; 1586 int error, szsigcode, szps; 1587 char canary[sizeof(long) * 8]; 1588 1589 szps = sizeof(pagesizes[0]) * MAXPAGESIZES; 1590 /* 1591 * Calculate string base and vector table pointers. 1592 * Also deal with signal trampoline code for this exec type. 1593 */ 1594 if (imgp->execpath != NULL && imgp->auxargs != NULL) 1595 execpath_len = strlen(imgp->execpath) + 1; 1596 else 1597 execpath_len = 0; 1598 p = imgp->proc; 1599 szsigcode = 0; 1600 arginfo = (struct ps_strings *)p->p_sysent->sv_psstrings; 1601 if (p->p_sysent->sv_sigcode_base == 0) { 1602 if (p->p_sysent->sv_szsigcode != NULL) 1603 szsigcode = *(p->p_sysent->sv_szsigcode); 1604 } 1605 destp = (uintptr_t)arginfo; 1606 1607 /* 1608 * install sigcode 1609 */ 1610 if (szsigcode != 0) { 1611 destp -= szsigcode; 1612 destp = rounddown2(destp, sizeof(void *)); 1613 error = copyout(p->p_sysent->sv_sigcode, (void *)destp, 1614 szsigcode); 1615 if (error != 0) 1616 return (error); 1617 } 1618 1619 /* 1620 * Copy the image path for the rtld. 1621 */ 1622 if (execpath_len != 0) { 1623 destp -= execpath_len; 1624 destp = rounddown2(destp, sizeof(void *)); 1625 imgp->execpathp = destp; 1626 error = copyout(imgp->execpath, (void *)destp, execpath_len); 1627 if (error != 0) 1628 return (error); 1629 } 1630 1631 /* 1632 * Prepare the canary for SSP. 1633 */ 1634 arc4rand(canary, sizeof(canary), 0); 1635 destp -= sizeof(canary); 1636 imgp->canary = destp; 1637 error = copyout(canary, (void *)destp, sizeof(canary)); 1638 if (error != 0) 1639 return (error); 1640 imgp->canarylen = sizeof(canary); 1641 1642 /* 1643 * Prepare the pagesizes array. 1644 */ 1645 destp -= szps; 1646 destp = rounddown2(destp, sizeof(void *)); 1647 imgp->pagesizes = destp; 1648 error = copyout(pagesizes, (void *)destp, szps); 1649 if (error != 0) 1650 return (error); 1651 imgp->pagesizeslen = szps; 1652 1653 /* 1654 * Allocate room for the argument and environment strings. 1655 */ 1656 destp -= ARG_MAX - imgp->args->stringspace; 1657 destp = rounddown2(destp, sizeof(void *)); 1658 ustringp = destp; 1659 1660 if (imgp->sysent->sv_stackgap != NULL) 1661 imgp->sysent->sv_stackgap(imgp, &destp); 1662 1663 if (imgp->auxargs) { 1664 /* 1665 * Allocate room on the stack for the ELF auxargs 1666 * array. It has up to AT_COUNT entries. 1667 */ 1668 destp -= AT_COUNT * sizeof(Elf_Auxinfo); 1669 destp = rounddown2(destp, sizeof(void *)); 1670 } 1671 1672 vectp = (char **)destp; 1673 1674 /* 1675 * Allocate room for the argv[] and env vectors including the 1676 * terminating NULL pointers. 1677 */ 1678 vectp -= imgp->args->argc + 1 + imgp->args->envc + 1; 1679 1680 /* 1681 * vectp also becomes our initial stack base 1682 */ 1683 *stack_base = (uintptr_t)vectp; 1684 1685 stringp = imgp->args->begin_argv; 1686 argc = imgp->args->argc; 1687 envc = imgp->args->envc; 1688 1689 /* 1690 * Copy out strings - arguments and environment. 1691 */ 1692 error = copyout(stringp, (void *)ustringp, 1693 ARG_MAX - imgp->args->stringspace); 1694 if (error != 0) 1695 return (error); 1696 1697 /* 1698 * Fill in "ps_strings" struct for ps, w, etc. 1699 */ 1700 if (suword(&arginfo->ps_argvstr, (long)(intptr_t)vectp) != 0 || 1701 suword32(&arginfo->ps_nargvstr, argc) != 0) 1702 return (EFAULT); 1703 1704 /* 1705 * Fill in argument portion of vector table. 1706 */ 1707 for (; argc > 0; --argc) { 1708 if (suword(vectp++, ustringp) != 0) 1709 return (EFAULT); 1710 while (*stringp++ != 0) 1711 ustringp++; 1712 ustringp++; 1713 } 1714 1715 /* a null vector table pointer separates the argp's from the envp's */ 1716 if (suword(vectp++, 0) != 0) 1717 return (EFAULT); 1718 1719 if (suword(&arginfo->ps_envstr, (long)(intptr_t)vectp) != 0 || 1720 suword32(&arginfo->ps_nenvstr, envc) != 0) 1721 return (EFAULT); 1722 1723 /* 1724 * Fill in environment portion of vector table. 1725 */ 1726 for (; envc > 0; --envc) { 1727 if (suword(vectp++, ustringp) != 0) 1728 return (EFAULT); 1729 while (*stringp++ != 0) 1730 ustringp++; 1731 ustringp++; 1732 } 1733 1734 /* end of vector table is a null pointer */ 1735 if (suword(vectp, 0) != 0) 1736 return (EFAULT); 1737 1738 if (imgp->auxargs) { 1739 vectp++; 1740 error = imgp->sysent->sv_copyout_auxargs(imgp, 1741 (uintptr_t)vectp); 1742 if (error != 0) 1743 return (error); 1744 } 1745 1746 return (0); 1747 } 1748 1749 /* 1750 * Check permissions of file to execute. 1751 * Called with imgp->vp locked. 1752 * Return 0 for success or error code on failure. 1753 */ 1754 int 1755 exec_check_permissions(struct image_params *imgp) 1756 { 1757 struct vnode *vp = imgp->vp; 1758 struct vattr *attr = imgp->attr; 1759 struct thread *td; 1760 int error; 1761 1762 td = curthread; 1763 1764 /* Get file attributes */ 1765 error = VOP_GETATTR(vp, attr, td->td_ucred); 1766 if (error) 1767 return (error); 1768 1769 #ifdef MAC 1770 error = mac_vnode_check_exec(td->td_ucred, imgp->vp, imgp); 1771 if (error) 1772 return (error); 1773 #endif 1774 1775 /* 1776 * 1) Check if file execution is disabled for the filesystem that 1777 * this file resides on. 1778 * 2) Ensure that at least one execute bit is on. Otherwise, a 1779 * privileged user will always succeed, and we don't want this 1780 * to happen unless the file really is executable. 1781 * 3) Ensure that the file is a regular file. 1782 */ 1783 if ((vp->v_mount->mnt_flag & MNT_NOEXEC) || 1784 (attr->va_mode & (S_IXUSR | S_IXGRP | S_IXOTH)) == 0 || 1785 (attr->va_type != VREG)) 1786 return (EACCES); 1787 1788 /* 1789 * Zero length files can't be exec'd 1790 */ 1791 if (attr->va_size == 0) 1792 return (ENOEXEC); 1793 1794 /* 1795 * Check for execute permission to file based on current credentials. 1796 */ 1797 error = VOP_ACCESS(vp, VEXEC, td->td_ucred, td); 1798 if (error) 1799 return (error); 1800 1801 /* 1802 * Check number of open-for-writes on the file and deny execution 1803 * if there are any. 1804 * 1805 * Add a text reference now so no one can write to the 1806 * executable while we're activating it. 1807 * 1808 * Remember if this was set before and unset it in case this is not 1809 * actually an executable image. 1810 */ 1811 error = VOP_SET_TEXT(vp); 1812 if (error != 0) 1813 return (error); 1814 imgp->textset = true; 1815 1816 /* 1817 * Call filesystem specific open routine (which does nothing in the 1818 * general case). 1819 */ 1820 error = VOP_OPEN(vp, FREAD, td->td_ucred, td, NULL); 1821 if (error == 0) 1822 imgp->opened = 1; 1823 return (error); 1824 } 1825 1826 /* 1827 * Exec handler registration 1828 */ 1829 int 1830 exec_register(const struct execsw *execsw_arg) 1831 { 1832 const struct execsw **es, **xs, **newexecsw; 1833 u_int count = 2; /* New slot and trailing NULL */ 1834 1835 if (execsw) 1836 for (es = execsw; *es; es++) 1837 count++; 1838 newexecsw = malloc(count * sizeof(*es), M_TEMP, M_WAITOK); 1839 xs = newexecsw; 1840 if (execsw) 1841 for (es = execsw; *es; es++) 1842 *xs++ = *es; 1843 *xs++ = execsw_arg; 1844 *xs = NULL; 1845 if (execsw) 1846 free(execsw, M_TEMP); 1847 execsw = newexecsw; 1848 return (0); 1849 } 1850 1851 int 1852 exec_unregister(const struct execsw *execsw_arg) 1853 { 1854 const struct execsw **es, **xs, **newexecsw; 1855 int count = 1; 1856 1857 if (execsw == NULL) 1858 panic("unregister with no handlers left?\n"); 1859 1860 for (es = execsw; *es; es++) { 1861 if (*es == execsw_arg) 1862 break; 1863 } 1864 if (*es == NULL) 1865 return (ENOENT); 1866 for (es = execsw; *es; es++) 1867 if (*es != execsw_arg) 1868 count++; 1869 newexecsw = malloc(count * sizeof(*es), M_TEMP, M_WAITOK); 1870 xs = newexecsw; 1871 for (es = execsw; *es; es++) 1872 if (*es != execsw_arg) 1873 *xs++ = *es; 1874 *xs = NULL; 1875 if (execsw) 1876 free(execsw, M_TEMP); 1877 execsw = newexecsw; 1878 return (0); 1879 } 1880