1 /*- 2 * Copyright (c) 1993, David Greenman 3 * All rights reserved. 4 * 5 * Redistribution and use in source and binary forms, with or without 6 * modification, are permitted provided that the following conditions 7 * are met: 8 * 1. Redistributions of source code must retain the above copyright 9 * notice, this list of conditions and the following disclaimer. 10 * 2. Redistributions in binary form must reproduce the above copyright 11 * notice, this list of conditions and the following disclaimer in the 12 * documentation and/or other materials provided with the distribution. 13 * 14 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND 15 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 16 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 17 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE 18 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 19 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 20 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 21 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 22 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 23 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 24 * SUCH DAMAGE. 25 */ 26 27 #include <sys/cdefs.h> 28 __FBSDID("$FreeBSD$"); 29 30 #include "opt_capsicum.h" 31 #include "opt_compat.h" 32 #include "opt_hwpmc_hooks.h" 33 #include "opt_ktrace.h" 34 #include "opt_vm.h" 35 36 #include <sys/param.h> 37 #include <sys/systm.h> 38 #include <sys/acct.h> 39 #include <sys/capsicum.h> 40 #include <sys/eventhandler.h> 41 #include <sys/exec.h> 42 #include <sys/fcntl.h> 43 #include <sys/filedesc.h> 44 #include <sys/imgact.h> 45 #include <sys/imgact_elf.h> 46 #include <sys/kernel.h> 47 #include <sys/lock.h> 48 #include <sys/malloc.h> 49 #include <sys/mman.h> 50 #include <sys/mount.h> 51 #include <sys/mutex.h> 52 #include <sys/namei.h> 53 #include <sys/pioctl.h> 54 #include <sys/priv.h> 55 #include <sys/proc.h> 56 #include <sys/ptrace.h> 57 #include <sys/resourcevar.h> 58 #include <sys/rwlock.h> 59 #include <sys/sched.h> 60 #include <sys/sdt.h> 61 #include <sys/sf_buf.h> 62 #include <sys/shm.h> 63 #include <sys/signalvar.h> 64 #include <sys/smp.h> 65 #include <sys/stat.h> 66 #include <sys/syscallsubr.h> 67 #include <sys/sysctl.h> 68 #include <sys/sysent.h> 69 #include <sys/sysproto.h> 70 #include <sys/vnode.h> 71 #include <sys/wait.h> 72 #ifdef KTRACE 73 #include <sys/ktrace.h> 74 #endif 75 76 #include <vm/vm.h> 77 #include <vm/vm_param.h> 78 #include <vm/pmap.h> 79 #include <vm/vm_page.h> 80 #include <vm/vm_map.h> 81 #include <vm/vm_kern.h> 82 #include <vm/vm_extern.h> 83 #include <vm/vm_object.h> 84 #include <vm/vm_pager.h> 85 86 #ifdef HWPMC_HOOKS 87 #include <sys/pmckern.h> 88 #endif 89 90 #include <machine/reg.h> 91 92 #include <security/audit/audit.h> 93 #include <security/mac/mac_framework.h> 94 95 #ifdef KDTRACE_HOOKS 96 #include <sys/dtrace_bsd.h> 97 dtrace_execexit_func_t dtrace_fasttrap_exec; 98 #endif 99 100 SDT_PROVIDER_DECLARE(proc); 101 SDT_PROBE_DEFINE1(proc, , , exec, "char *"); 102 SDT_PROBE_DEFINE1(proc, , , exec__failure, "int"); 103 SDT_PROBE_DEFINE1(proc, , , exec__success, "char *"); 104 105 MALLOC_DEFINE(M_PARGS, "proc-args", "Process arguments"); 106 107 int coredump_pack_fileinfo = 1; 108 SYSCTL_INT(_kern, OID_AUTO, coredump_pack_fileinfo, CTLFLAG_RWTUN, 109 &coredump_pack_fileinfo, 0, 110 "Enable file path packing in 'procstat -f' coredump notes"); 111 112 int coredump_pack_vmmapinfo = 1; 113 SYSCTL_INT(_kern, OID_AUTO, coredump_pack_vmmapinfo, CTLFLAG_RWTUN, 114 &coredump_pack_vmmapinfo, 0, 115 "Enable file path packing in 'procstat -v' coredump notes"); 116 117 static int sysctl_kern_ps_strings(SYSCTL_HANDLER_ARGS); 118 static int sysctl_kern_usrstack(SYSCTL_HANDLER_ARGS); 119 static int sysctl_kern_stackprot(SYSCTL_HANDLER_ARGS); 120 static int do_execve(struct thread *td, struct image_args *args, 121 struct mac *mac_p); 122 123 /* XXX This should be vm_size_t. */ 124 SYSCTL_PROC(_kern, KERN_PS_STRINGS, ps_strings, CTLTYPE_ULONG|CTLFLAG_RD| 125 CTLFLAG_MPSAFE, NULL, 0, sysctl_kern_ps_strings, "LU", ""); 126 127 /* XXX This should be vm_size_t. */ 128 SYSCTL_PROC(_kern, KERN_USRSTACK, usrstack, CTLTYPE_ULONG|CTLFLAG_RD| 129 CTLFLAG_CAPRD|CTLFLAG_MPSAFE, NULL, 0, sysctl_kern_usrstack, "LU", ""); 130 131 SYSCTL_PROC(_kern, OID_AUTO, stackprot, CTLTYPE_INT|CTLFLAG_RD|CTLFLAG_MPSAFE, 132 NULL, 0, sysctl_kern_stackprot, "I", ""); 133 134 u_long ps_arg_cache_limit = PAGE_SIZE / 16; 135 SYSCTL_ULONG(_kern, OID_AUTO, ps_arg_cache_limit, CTLFLAG_RW, 136 &ps_arg_cache_limit, 0, ""); 137 138 static int disallow_high_osrel; 139 SYSCTL_INT(_kern, OID_AUTO, disallow_high_osrel, CTLFLAG_RW, 140 &disallow_high_osrel, 0, 141 "Disallow execution of binaries built for higher version of the world"); 142 143 static int map_at_zero = 0; 144 SYSCTL_INT(_security_bsd, OID_AUTO, map_at_zero, CTLFLAG_RWTUN, &map_at_zero, 0, 145 "Permit processes to map an object at virtual address 0."); 146 147 static int 148 sysctl_kern_ps_strings(SYSCTL_HANDLER_ARGS) 149 { 150 struct proc *p; 151 int error; 152 153 p = curproc; 154 #ifdef SCTL_MASK32 155 if (req->flags & SCTL_MASK32) { 156 unsigned int val; 157 val = (unsigned int)p->p_sysent->sv_psstrings; 158 error = SYSCTL_OUT(req, &val, sizeof(val)); 159 } else 160 #endif 161 error = SYSCTL_OUT(req, &p->p_sysent->sv_psstrings, 162 sizeof(p->p_sysent->sv_psstrings)); 163 return error; 164 } 165 166 static int 167 sysctl_kern_usrstack(SYSCTL_HANDLER_ARGS) 168 { 169 struct proc *p; 170 int error; 171 172 p = curproc; 173 #ifdef SCTL_MASK32 174 if (req->flags & SCTL_MASK32) { 175 unsigned int val; 176 val = (unsigned int)p->p_sysent->sv_usrstack; 177 error = SYSCTL_OUT(req, &val, sizeof(val)); 178 } else 179 #endif 180 error = SYSCTL_OUT(req, &p->p_sysent->sv_usrstack, 181 sizeof(p->p_sysent->sv_usrstack)); 182 return error; 183 } 184 185 static int 186 sysctl_kern_stackprot(SYSCTL_HANDLER_ARGS) 187 { 188 struct proc *p; 189 190 p = curproc; 191 return (SYSCTL_OUT(req, &p->p_sysent->sv_stackprot, 192 sizeof(p->p_sysent->sv_stackprot))); 193 } 194 195 /* 196 * Each of the items is a pointer to a `const struct execsw', hence the 197 * double pointer here. 198 */ 199 static const struct execsw **execsw; 200 201 #ifndef _SYS_SYSPROTO_H_ 202 struct execve_args { 203 char *fname; 204 char **argv; 205 char **envv; 206 }; 207 #endif 208 209 int 210 sys_execve(struct thread *td, struct execve_args *uap) 211 { 212 struct image_args args; 213 struct vmspace *oldvmspace; 214 int error; 215 216 error = pre_execve(td, &oldvmspace); 217 if (error != 0) 218 return (error); 219 error = exec_copyin_args(&args, uap->fname, UIO_USERSPACE, 220 uap->argv, uap->envv); 221 if (error == 0) 222 error = kern_execve(td, &args, NULL); 223 post_execve(td, error, oldvmspace); 224 return (error); 225 } 226 227 #ifndef _SYS_SYSPROTO_H_ 228 struct fexecve_args { 229 int fd; 230 char **argv; 231 char **envv; 232 } 233 #endif 234 int 235 sys_fexecve(struct thread *td, struct fexecve_args *uap) 236 { 237 struct image_args args; 238 struct vmspace *oldvmspace; 239 int error; 240 241 error = pre_execve(td, &oldvmspace); 242 if (error != 0) 243 return (error); 244 error = exec_copyin_args(&args, NULL, UIO_SYSSPACE, 245 uap->argv, uap->envv); 246 if (error == 0) { 247 args.fd = uap->fd; 248 error = kern_execve(td, &args, NULL); 249 } 250 post_execve(td, error, oldvmspace); 251 return (error); 252 } 253 254 #ifndef _SYS_SYSPROTO_H_ 255 struct __mac_execve_args { 256 char *fname; 257 char **argv; 258 char **envv; 259 struct mac *mac_p; 260 }; 261 #endif 262 263 int 264 sys___mac_execve(struct thread *td, struct __mac_execve_args *uap) 265 { 266 #ifdef MAC 267 struct image_args args; 268 struct vmspace *oldvmspace; 269 int error; 270 271 error = pre_execve(td, &oldvmspace); 272 if (error != 0) 273 return (error); 274 error = exec_copyin_args(&args, uap->fname, UIO_USERSPACE, 275 uap->argv, uap->envv); 276 if (error == 0) 277 error = kern_execve(td, &args, uap->mac_p); 278 post_execve(td, error, oldvmspace); 279 return (error); 280 #else 281 return (ENOSYS); 282 #endif 283 } 284 285 int 286 pre_execve(struct thread *td, struct vmspace **oldvmspace) 287 { 288 struct proc *p; 289 int error; 290 291 KASSERT(td == curthread, ("non-current thread %p", td)); 292 error = 0; 293 p = td->td_proc; 294 if ((p->p_flag & P_HADTHREADS) != 0) { 295 PROC_LOCK(p); 296 if (thread_single(p, SINGLE_BOUNDARY) != 0) 297 error = ERESTART; 298 PROC_UNLOCK(p); 299 } 300 KASSERT(error != 0 || (td->td_pflags & TDP_EXECVMSPC) == 0, 301 ("nested execve")); 302 *oldvmspace = p->p_vmspace; 303 return (error); 304 } 305 306 void 307 post_execve(struct thread *td, int error, struct vmspace *oldvmspace) 308 { 309 struct proc *p; 310 311 KASSERT(td == curthread, ("non-current thread %p", td)); 312 p = td->td_proc; 313 if ((p->p_flag & P_HADTHREADS) != 0) { 314 PROC_LOCK(p); 315 /* 316 * If success, we upgrade to SINGLE_EXIT state to 317 * force other threads to suicide. 318 */ 319 if (error == 0) 320 thread_single(p, SINGLE_EXIT); 321 else 322 thread_single_end(p, SINGLE_BOUNDARY); 323 PROC_UNLOCK(p); 324 } 325 if ((td->td_pflags & TDP_EXECVMSPC) != 0) { 326 KASSERT(p->p_vmspace != oldvmspace, 327 ("oldvmspace still used")); 328 vmspace_free(oldvmspace); 329 td->td_pflags &= ~TDP_EXECVMSPC; 330 } 331 } 332 333 /* 334 * XXX: kern_execve has the astonishing property of not always returning to 335 * the caller. If sufficiently bad things happen during the call to 336 * do_execve(), it can end up calling exit1(); as a result, callers must 337 * avoid doing anything which they might need to undo (e.g., allocating 338 * memory). 339 */ 340 int 341 kern_execve(struct thread *td, struct image_args *args, struct mac *mac_p) 342 { 343 344 AUDIT_ARG_ARGV(args->begin_argv, args->argc, 345 args->begin_envv - args->begin_argv); 346 AUDIT_ARG_ENVV(args->begin_envv, args->envc, 347 args->endp - args->begin_envv); 348 return (do_execve(td, args, mac_p)); 349 } 350 351 /* 352 * In-kernel implementation of execve(). All arguments are assumed to be 353 * userspace pointers from the passed thread. 354 */ 355 static int 356 do_execve(struct thread *td, struct image_args *args, struct mac *mac_p) 357 { 358 struct proc *p = td->td_proc; 359 struct nameidata nd; 360 struct ucred *oldcred; 361 struct uidinfo *euip = NULL; 362 register_t *stack_base; 363 int error, i; 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 cap_rights_t rights; 375 int credential_changing; 376 int textset; 377 #ifdef MAC 378 struct label *interpvplabel = NULL; 379 int will_transition; 380 #endif 381 #ifdef HWPMC_HOOKS 382 struct pmckern_procexec pe; 383 #endif 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; 409 410 #ifdef MAC 411 error = mac_execve_enter(imgp, mac_p); 412 if (error) 413 goto exec_fail; 414 #endif 415 416 /* 417 * Translate the file name. namei() returns a vnode pointer 418 * in ni_vp among other things. 419 * 420 * XXXAUDIT: It would be desirable to also audit the name of the 421 * interpreter if this is an interpreted binary. 422 */ 423 if (args->fname != NULL) { 424 NDINIT(&nd, LOOKUP, ISOPEN | LOCKLEAF | FOLLOW | SAVENAME 425 | AUDITVNODE1, UIO_SYSSPACE, args->fname, td); 426 } 427 428 SDT_PROBE1(proc, , , exec, args->fname); 429 430 interpret: 431 if (args->fname != NULL) { 432 #ifdef CAPABILITY_MODE 433 /* 434 * While capability mode can't reach this point via direct 435 * path arguments to execve(), we also don't allow 436 * interpreters to be used in capability mode (for now). 437 * Catch indirect lookups and return a permissions error. 438 */ 439 if (IN_CAPABILITY_MODE(td)) { 440 error = ECAPMODE; 441 goto exec_fail; 442 } 443 #endif 444 error = namei(&nd); 445 if (error) 446 goto exec_fail; 447 448 newtextvp = nd.ni_vp; 449 imgp->vp = newtextvp; 450 } else { 451 AUDIT_ARG_FD(args->fd); 452 /* 453 * Descriptors opened only with O_EXEC or O_RDONLY are allowed. 454 */ 455 error = fgetvp_exec(td, args->fd, 456 cap_rights_init(&rights, CAP_FEXECVE), &newtextvp); 457 if (error) 458 goto exec_fail; 459 vn_lock(newtextvp, LK_EXCLUSIVE | LK_RETRY); 460 AUDIT_ARG_VNODE1(newtextvp); 461 imgp->vp = newtextvp; 462 } 463 464 /* 465 * Check file permissions (also 'opens' file) 466 */ 467 error = exec_check_permissions(imgp); 468 if (error) 469 goto exec_fail_dealloc; 470 471 imgp->object = imgp->vp->v_object; 472 if (imgp->object != NULL) 473 vm_object_reference(imgp->object); 474 475 /* 476 * Set VV_TEXT now so no one can write to the executable while we're 477 * activating it. 478 * 479 * Remember if this was set before and unset it in case this is not 480 * actually an executable image. 481 */ 482 textset = VOP_IS_TEXT(imgp->vp); 483 VOP_SET_TEXT(imgp->vp); 484 485 error = exec_map_first_page(imgp); 486 if (error) 487 goto exec_fail_dealloc; 488 489 imgp->proc->p_osrel = 0; 490 491 /* 492 * Implement image setuid/setgid. 493 * 494 * Determine new credentials before attempting image activators 495 * so that it can be used by process_exec handlers to determine 496 * credential/setid changes. 497 * 498 * Don't honor setuid/setgid if the filesystem prohibits it or if 499 * the process is being traced. 500 * 501 * We disable setuid/setgid/etc in capability mode on the basis 502 * that most setugid applications are not written with that 503 * environment in mind, and will therefore almost certainly operate 504 * incorrectly. In principle there's no reason that setugid 505 * applications might not be useful in capability mode, so we may want 506 * to reconsider this conservative design choice in the future. 507 * 508 * XXXMAC: For the time being, use NOSUID to also prohibit 509 * transitions on the file system. 510 */ 511 credential_changing = 0; 512 credential_changing |= (attr.va_mode & S_ISUID) && 513 oldcred->cr_uid != attr.va_uid; 514 credential_changing |= (attr.va_mode & S_ISGID) && 515 oldcred->cr_gid != attr.va_gid; 516 #ifdef MAC 517 will_transition = mac_vnode_execve_will_transition(oldcred, imgp->vp, 518 interpvplabel, imgp); 519 credential_changing |= will_transition; 520 #endif 521 522 if (credential_changing && 523 #ifdef CAPABILITY_MODE 524 ((oldcred->cr_flags & CRED_FLAG_CAPMODE) == 0) && 525 #endif 526 (imgp->vp->v_mount->mnt_flag & MNT_NOSUID) == 0 && 527 (p->p_flag & P_TRACED) == 0) { 528 imgp->credential_setid = true; 529 VOP_UNLOCK(imgp->vp, 0); 530 imgp->newcred = crdup(oldcred); 531 if (attr.va_mode & S_ISUID) { 532 euip = uifind(attr.va_uid); 533 change_euid(imgp->newcred, euip); 534 } 535 vn_lock(imgp->vp, LK_EXCLUSIVE | LK_RETRY); 536 if (attr.va_mode & S_ISGID) 537 change_egid(imgp->newcred, attr.va_gid); 538 /* 539 * Implement correct POSIX saved-id behavior. 540 * 541 * XXXMAC: Note that the current logic will save the 542 * uid and gid if a MAC domain transition occurs, even 543 * though maybe it shouldn't. 544 */ 545 change_svuid(imgp->newcred, imgp->newcred->cr_uid); 546 change_svgid(imgp->newcred, imgp->newcred->cr_gid); 547 } else { 548 /* 549 * Implement correct POSIX saved-id behavior. 550 * 551 * XXX: It's not clear that the existing behavior is 552 * POSIX-compliant. A number of sources indicate that the 553 * saved uid/gid should only be updated if the new ruid is 554 * not equal to the old ruid, or the new euid is not equal 555 * to the old euid and the new euid is not equal to the old 556 * ruid. The FreeBSD code always updates the saved uid/gid. 557 * Also, this code uses the new (replaced) euid and egid as 558 * the source, which may or may not be the right ones to use. 559 */ 560 if (oldcred->cr_svuid != oldcred->cr_uid || 561 oldcred->cr_svgid != oldcred->cr_gid) { 562 VOP_UNLOCK(imgp->vp, 0); 563 imgp->newcred = crdup(oldcred); 564 vn_lock(imgp->vp, LK_EXCLUSIVE | LK_RETRY); 565 change_svuid(imgp->newcred, imgp->newcred->cr_uid); 566 change_svgid(imgp->newcred, imgp->newcred->cr_gid); 567 } 568 } 569 /* The new credentials are installed into the process later. */ 570 571 /* 572 * Do the best to calculate the full path to the image file. 573 */ 574 if (args->fname != NULL && args->fname[0] == '/') 575 imgp->execpath = args->fname; 576 else { 577 VOP_UNLOCK(imgp->vp, 0); 578 if (vn_fullpath(td, imgp->vp, &imgp->execpath, 579 &imgp->freepath) != 0) 580 imgp->execpath = args->fname; 581 vn_lock(imgp->vp, LK_EXCLUSIVE | LK_RETRY); 582 } 583 584 /* 585 * If the current process has a special image activator it 586 * wants to try first, call it. For example, emulating shell 587 * scripts differently. 588 */ 589 error = -1; 590 if ((img_first = imgp->proc->p_sysent->sv_imgact_try) != NULL) 591 error = img_first(imgp); 592 593 /* 594 * Loop through the list of image activators, calling each one. 595 * An activator returns -1 if there is no match, 0 on success, 596 * and an error otherwise. 597 */ 598 for (i = 0; error == -1 && execsw[i]; ++i) { 599 if (execsw[i]->ex_imgact == NULL || 600 execsw[i]->ex_imgact == img_first) { 601 continue; 602 } 603 error = (*execsw[i]->ex_imgact)(imgp); 604 } 605 606 if (error) { 607 if (error == -1) { 608 if (textset == 0) 609 VOP_UNSET_TEXT(imgp->vp); 610 error = ENOEXEC; 611 } 612 goto exec_fail_dealloc; 613 } 614 615 /* 616 * Special interpreter operation, cleanup and loop up to try to 617 * activate the interpreter. 618 */ 619 if (imgp->interpreted) { 620 exec_unmap_first_page(imgp); 621 /* 622 * VV_TEXT needs to be unset for scripts. There is a short 623 * period before we determine that something is a script where 624 * VV_TEXT will be set. The vnode lock is held over this 625 * entire period so nothing should illegitimately be blocked. 626 */ 627 VOP_UNSET_TEXT(imgp->vp); 628 /* free name buffer and old vnode */ 629 if (args->fname != NULL) 630 NDFREE(&nd, NDF_ONLY_PNBUF); 631 #ifdef MAC 632 mac_execve_interpreter_enter(newtextvp, &interpvplabel); 633 #endif 634 if (imgp->opened) { 635 VOP_CLOSE(newtextvp, FREAD, td->td_ucred, td); 636 imgp->opened = 0; 637 } 638 vput(newtextvp); 639 vm_object_deallocate(imgp->object); 640 imgp->object = NULL; 641 imgp->credential_setid = false; 642 if (imgp->newcred != NULL) { 643 crfree(imgp->newcred); 644 imgp->newcred = NULL; 645 } 646 imgp->execpath = NULL; 647 free(imgp->freepath, M_TEMP); 648 imgp->freepath = NULL; 649 /* set new name to that of the interpreter */ 650 NDINIT(&nd, LOOKUP, LOCKLEAF | FOLLOW | SAVENAME, 651 UIO_SYSSPACE, imgp->interpreter_name, td); 652 args->fname = imgp->interpreter_name; 653 goto interpret; 654 } 655 656 /* 657 * NB: We unlock the vnode here because it is believed that none 658 * of the sv_copyout_strings/sv_fixup operations require the vnode. 659 */ 660 VOP_UNLOCK(imgp->vp, 0); 661 662 if (disallow_high_osrel && 663 P_OSREL_MAJOR(p->p_osrel) > P_OSREL_MAJOR(__FreeBSD_version)) { 664 error = ENOEXEC; 665 uprintf("Osrel %d for image %s too high\n", p->p_osrel, 666 imgp->execpath != NULL ? imgp->execpath : "<unresolved>"); 667 vn_lock(imgp->vp, LK_SHARED | LK_RETRY); 668 goto exec_fail_dealloc; 669 } 670 671 /* ABI enforces the use of Capsicum. Switch into capabilities mode. */ 672 if (SV_PROC_FLAG(p, SV_CAPSICUM)) 673 sys_cap_enter(td, NULL); 674 675 /* 676 * Copy out strings (args and env) and initialize stack base 677 */ 678 if (p->p_sysent->sv_copyout_strings) 679 stack_base = (*p->p_sysent->sv_copyout_strings)(imgp); 680 else 681 stack_base = exec_copyout_strings(imgp); 682 683 /* 684 * If custom stack fixup routine present for this process 685 * let it do the stack setup. 686 * Else stuff argument count as first item on stack 687 */ 688 if (p->p_sysent->sv_fixup != NULL) 689 (*p->p_sysent->sv_fixup)(&stack_base, imgp); 690 else 691 suword(--stack_base, imgp->args->argc); 692 693 if (args->fdp != NULL) { 694 /* Install a brand new file descriptor table. */ 695 fdinstall_remapped(td, args->fdp); 696 args->fdp = NULL; 697 } else { 698 /* 699 * Keep on using the existing file descriptor table. For 700 * security and other reasons, the file descriptor table 701 * cannot be shared after an exec. 702 */ 703 fdunshare(td); 704 /* close files on exec */ 705 fdcloseexec(td); 706 } 707 708 /* 709 * Malloc things before we need locks. 710 */ 711 i = imgp->args->begin_envv - imgp->args->begin_argv; 712 /* Cache arguments if they fit inside our allowance */ 713 if (ps_arg_cache_limit >= i + sizeof(struct pargs)) { 714 newargs = pargs_alloc(i); 715 bcopy(imgp->args->begin_argv, newargs->ar_args, i); 716 } 717 718 /* 719 * For security and other reasons, signal handlers cannot 720 * be shared after an exec. The new process gets a copy of the old 721 * handlers. In execsigs(), the new process will have its signals 722 * reset. 723 */ 724 if (sigacts_shared(p->p_sigacts)) { 725 oldsigacts = p->p_sigacts; 726 newsigacts = sigacts_alloc(); 727 sigacts_copy(newsigacts, oldsigacts); 728 } 729 730 vn_lock(imgp->vp, LK_SHARED | LK_RETRY); 731 732 PROC_LOCK(p); 733 if (oldsigacts) 734 p->p_sigacts = newsigacts; 735 /* Stop profiling */ 736 stopprofclock(p); 737 738 /* reset caught signals */ 739 execsigs(p); 740 741 /* name this process - nameiexec(p, ndp) */ 742 bzero(p->p_comm, sizeof(p->p_comm)); 743 if (args->fname) 744 bcopy(nd.ni_cnd.cn_nameptr, p->p_comm, 745 min(nd.ni_cnd.cn_namelen, MAXCOMLEN)); 746 else if (vn_commname(newtextvp, p->p_comm, sizeof(p->p_comm)) != 0) 747 bcopy(fexecv_proc_title, p->p_comm, sizeof(fexecv_proc_title)); 748 bcopy(p->p_comm, td->td_name, sizeof(td->td_name)); 749 #ifdef KTR 750 sched_clear_tdname(td); 751 #endif 752 753 /* 754 * mark as execed, wakeup the process that vforked (if any) and tell 755 * it that it now has its own resources back 756 */ 757 p->p_flag |= P_EXEC; 758 if ((p->p_flag2 & P2_NOTRACE_EXEC) == 0) 759 p->p_flag2 &= ~P2_NOTRACE; 760 if (p->p_flag & P_PPWAIT) { 761 p->p_flag &= ~(P_PPWAIT | P_PPTRACE); 762 cv_broadcast(&p->p_pwait); 763 /* STOPs are no longer ignored, arrange for AST */ 764 signotify(td); 765 } 766 767 /* 768 * Implement image setuid/setgid installation. 769 */ 770 if (imgp->credential_setid) { 771 /* 772 * Turn off syscall tracing for set-id programs, except for 773 * root. Record any set-id flags first to make sure that 774 * we do not regain any tracing during a possible block. 775 */ 776 setsugid(p); 777 778 #ifdef KTRACE 779 if (p->p_tracecred != NULL && 780 priv_check_cred(p->p_tracecred, PRIV_DEBUG_DIFFCRED, 0)) 781 ktrprocexec(p, &tracecred, &tracevp); 782 #endif 783 /* 784 * Close any file descriptors 0..2 that reference procfs, 785 * then make sure file descriptors 0..2 are in use. 786 * 787 * Both fdsetugidsafety() and fdcheckstd() may call functions 788 * taking sleepable locks, so temporarily drop our locks. 789 */ 790 PROC_UNLOCK(p); 791 VOP_UNLOCK(imgp->vp, 0); 792 fdsetugidsafety(td); 793 error = fdcheckstd(td); 794 vn_lock(imgp->vp, LK_SHARED | LK_RETRY); 795 if (error != 0) 796 goto exec_fail_dealloc; 797 PROC_LOCK(p); 798 #ifdef MAC 799 if (will_transition) { 800 mac_vnode_execve_transition(oldcred, imgp->newcred, 801 imgp->vp, interpvplabel, imgp); 802 } 803 #endif 804 } else { 805 if (oldcred->cr_uid == oldcred->cr_ruid && 806 oldcred->cr_gid == oldcred->cr_rgid) 807 p->p_flag &= ~P_SUGID; 808 } 809 /* 810 * Set the new credentials. 811 */ 812 if (imgp->newcred != NULL) { 813 proc_set_cred(p, imgp->newcred); 814 crfree(oldcred); 815 oldcred = NULL; 816 } 817 818 /* 819 * Store the vp for use in procfs. This vnode was referenced by namei 820 * or fgetvp_exec. 821 */ 822 oldtextvp = p->p_textvp; 823 p->p_textvp = newtextvp; 824 825 #ifdef KDTRACE_HOOKS 826 /* 827 * Tell the DTrace fasttrap provider about the exec if it 828 * has declared an interest. 829 */ 830 if (dtrace_fasttrap_exec) 831 dtrace_fasttrap_exec(p); 832 #endif 833 834 /* 835 * Notify others that we exec'd, and clear the P_INEXEC flag 836 * as we're now a bona fide freshly-execed process. 837 */ 838 KNOTE_LOCKED(p->p_klist, NOTE_EXEC); 839 p->p_flag &= ~P_INEXEC; 840 841 /* clear "fork but no exec" flag, as we _are_ execing */ 842 p->p_acflag &= ~AFORK; 843 844 /* 845 * Free any previous argument cache and replace it with 846 * the new argument cache, if any. 847 */ 848 oldargs = p->p_args; 849 p->p_args = newargs; 850 newargs = NULL; 851 852 #ifdef HWPMC_HOOKS 853 /* 854 * Check if system-wide sampling is in effect or if the 855 * current process is using PMCs. If so, do exec() time 856 * processing. This processing needs to happen AFTER the 857 * P_INEXEC flag is cleared. 858 * 859 * The proc lock needs to be released before taking the PMC 860 * SX. 861 */ 862 if (PMC_SYSTEM_SAMPLING_ACTIVE() || PMC_PROC_IS_USING_PMCS(p)) { 863 PROC_UNLOCK(p); 864 VOP_UNLOCK(imgp->vp, 0); 865 pe.pm_credentialschanged = credential_changing; 866 pe.pm_entryaddr = imgp->entry_addr; 867 868 PMC_CALL_HOOK_X(td, PMC_FN_PROCESS_EXEC, (void *) &pe); 869 vn_lock(imgp->vp, LK_SHARED | LK_RETRY); 870 } else 871 PROC_UNLOCK(p); 872 #else /* !HWPMC_HOOKS */ 873 PROC_UNLOCK(p); 874 #endif 875 876 /* Set values passed into the program in registers. */ 877 if (p->p_sysent->sv_setregs) 878 (*p->p_sysent->sv_setregs)(td, imgp, 879 (u_long)(uintptr_t)stack_base); 880 else 881 exec_setregs(td, imgp, (u_long)(uintptr_t)stack_base); 882 883 vfs_mark_atime(imgp->vp, td->td_ucred); 884 885 SDT_PROBE1(proc, , , exec__success, args->fname); 886 887 exec_fail_dealloc: 888 if (imgp->firstpage != NULL) 889 exec_unmap_first_page(imgp); 890 891 if (imgp->vp != NULL) { 892 if (args->fname) 893 NDFREE(&nd, NDF_ONLY_PNBUF); 894 if (imgp->opened) 895 VOP_CLOSE(imgp->vp, FREAD, td->td_ucred, td); 896 if (error != 0) 897 vput(imgp->vp); 898 else 899 VOP_UNLOCK(imgp->vp, 0); 900 } 901 902 if (imgp->object != NULL) 903 vm_object_deallocate(imgp->object); 904 905 free(imgp->freepath, M_TEMP); 906 907 if (error == 0) { 908 PROC_LOCK(p); 909 if (p->p_ptevents & PTRACE_EXEC) 910 td->td_dbgflags |= TDB_EXEC; 911 PROC_UNLOCK(p); 912 913 /* 914 * Stop the process here if its stop event mask has 915 * the S_EXEC bit set. 916 */ 917 STOPEVENT(p, S_EXEC, 0); 918 } else { 919 exec_fail: 920 /* we're done here, clear P_INEXEC */ 921 PROC_LOCK(p); 922 p->p_flag &= ~P_INEXEC; 923 PROC_UNLOCK(p); 924 925 SDT_PROBE1(proc, , , exec__failure, error); 926 } 927 928 if (imgp->newcred != NULL && oldcred != NULL) 929 crfree(imgp->newcred); 930 931 #ifdef MAC 932 mac_execve_exit(imgp); 933 mac_execve_interpreter_exit(interpvplabel); 934 #endif 935 exec_free_args(args); 936 937 /* 938 * Handle deferred decrement of ref counts. 939 */ 940 if (oldtextvp != NULL) 941 vrele(oldtextvp); 942 #ifdef KTRACE 943 if (tracevp != NULL) 944 vrele(tracevp); 945 if (tracecred != NULL) 946 crfree(tracecred); 947 #endif 948 pargs_drop(oldargs); 949 pargs_drop(newargs); 950 if (oldsigacts != NULL) 951 sigacts_free(oldsigacts); 952 if (euip != NULL) 953 uifree(euip); 954 955 if (error && imgp->vmspace_destroyed) { 956 /* sorry, no more process anymore. exit gracefully */ 957 exit1(td, 0, SIGABRT); 958 /* NOT REACHED */ 959 } 960 961 #ifdef KTRACE 962 if (error == 0) 963 ktrprocctor(p); 964 #endif 965 966 return (error); 967 } 968 969 int 970 exec_map_first_page(imgp) 971 struct image_params *imgp; 972 { 973 int rv, i, after, initial_pagein; 974 vm_page_t ma[VM_INITIAL_PAGEIN]; 975 vm_object_t object; 976 977 if (imgp->firstpage != NULL) 978 exec_unmap_first_page(imgp); 979 980 object = imgp->vp->v_object; 981 if (object == NULL) 982 return (EACCES); 983 VM_OBJECT_WLOCK(object); 984 #if VM_NRESERVLEVEL > 0 985 vm_object_color(object, 0); 986 #endif 987 ma[0] = vm_page_grab(object, 0, VM_ALLOC_NORMAL | VM_ALLOC_NOBUSY); 988 if (ma[0]->valid != VM_PAGE_BITS_ALL) { 989 vm_page_xbusy(ma[0]); 990 if (!vm_pager_has_page(object, 0, NULL, &after)) { 991 vm_page_lock(ma[0]); 992 vm_page_free(ma[0]); 993 vm_page_unlock(ma[0]); 994 VM_OBJECT_WUNLOCK(object); 995 return (EIO); 996 } 997 initial_pagein = min(after, VM_INITIAL_PAGEIN); 998 KASSERT(initial_pagein <= object->size, 999 ("%s: initial_pagein %d object->size %ju", 1000 __func__, initial_pagein, (uintmax_t )object->size)); 1001 for (i = 1; i < initial_pagein; i++) { 1002 if ((ma[i] = vm_page_next(ma[i - 1])) != NULL) { 1003 if (ma[i]->valid) 1004 break; 1005 if (vm_page_tryxbusy(ma[i])) 1006 break; 1007 } else { 1008 ma[i] = vm_page_alloc(object, i, 1009 VM_ALLOC_NORMAL); 1010 if (ma[i] == NULL) 1011 break; 1012 } 1013 } 1014 initial_pagein = i; 1015 rv = vm_pager_get_pages(object, ma, initial_pagein, NULL, NULL); 1016 if (rv != VM_PAGER_OK) { 1017 for (i = 0; i < initial_pagein; i++) { 1018 vm_page_lock(ma[i]); 1019 vm_page_free(ma[i]); 1020 vm_page_unlock(ma[i]); 1021 } 1022 VM_OBJECT_WUNLOCK(object); 1023 return (EIO); 1024 } 1025 vm_page_xunbusy(ma[0]); 1026 for (i = 1; i < initial_pagein; i++) 1027 vm_page_readahead_finish(ma[i]); 1028 } 1029 vm_page_lock(ma[0]); 1030 vm_page_hold(ma[0]); 1031 vm_page_activate(ma[0]); 1032 vm_page_unlock(ma[0]); 1033 VM_OBJECT_WUNLOCK(object); 1034 1035 imgp->firstpage = sf_buf_alloc(ma[0], 0); 1036 imgp->image_header = (char *)sf_buf_kva(imgp->firstpage); 1037 1038 return (0); 1039 } 1040 1041 void 1042 exec_unmap_first_page(struct image_params *imgp) 1043 { 1044 vm_page_t m; 1045 1046 if (imgp->firstpage != NULL) { 1047 m = sf_buf_page(imgp->firstpage); 1048 sf_buf_free(imgp->firstpage); 1049 imgp->firstpage = NULL; 1050 vm_page_lock(m); 1051 vm_page_unhold(m); 1052 vm_page_unlock(m); 1053 } 1054 } 1055 1056 /* 1057 * Destroy old address space, and allocate a new stack. 1058 * The new stack is only sgrowsiz large because it is grown 1059 * automatically on a page fault. 1060 */ 1061 int 1062 exec_new_vmspace(struct image_params *imgp, struct sysentvec *sv) 1063 { 1064 int error; 1065 struct proc *p = imgp->proc; 1066 struct vmspace *vmspace = p->p_vmspace; 1067 vm_object_t obj; 1068 struct rlimit rlim_stack; 1069 vm_offset_t sv_minuser, stack_addr; 1070 vm_map_t map; 1071 u_long ssiz; 1072 1073 imgp->vmspace_destroyed = 1; 1074 imgp->sysent = sv; 1075 1076 /* May be called with Giant held */ 1077 EVENTHANDLER_INVOKE(process_exec, p, imgp); 1078 1079 /* 1080 * Blow away entire process VM, if address space not shared, 1081 * otherwise, create a new VM space so that other threads are 1082 * not disrupted 1083 */ 1084 map = &vmspace->vm_map; 1085 if (map_at_zero) 1086 sv_minuser = sv->sv_minuser; 1087 else 1088 sv_minuser = MAX(sv->sv_minuser, PAGE_SIZE); 1089 if (vmspace->vm_refcnt == 1 && vm_map_min(map) == sv_minuser && 1090 vm_map_max(map) == sv->sv_maxuser) { 1091 shmexit(vmspace); 1092 pmap_remove_pages(vmspace_pmap(vmspace)); 1093 vm_map_remove(map, vm_map_min(map), vm_map_max(map)); 1094 /* An exec terminates mlockall(MCL_FUTURE). */ 1095 vm_map_lock(map); 1096 vm_map_modflags(map, 0, MAP_WIREFUTURE); 1097 vm_map_unlock(map); 1098 } else { 1099 error = vmspace_exec(p, sv_minuser, sv->sv_maxuser); 1100 if (error) 1101 return (error); 1102 vmspace = p->p_vmspace; 1103 map = &vmspace->vm_map; 1104 } 1105 1106 /* Map a shared page */ 1107 obj = sv->sv_shared_page_obj; 1108 if (obj != NULL) { 1109 vm_object_reference(obj); 1110 error = vm_map_fixed(map, obj, 0, 1111 sv->sv_shared_page_base, sv->sv_shared_page_len, 1112 VM_PROT_READ | VM_PROT_EXECUTE, 1113 VM_PROT_READ | VM_PROT_EXECUTE, 1114 MAP_INHERIT_SHARE | MAP_ACC_NO_CHARGE); 1115 if (error != KERN_SUCCESS) { 1116 vm_object_deallocate(obj); 1117 return (vm_mmap_to_errno(error)); 1118 } 1119 } 1120 1121 /* Allocate a new stack */ 1122 if (imgp->stack_sz != 0) { 1123 ssiz = trunc_page(imgp->stack_sz); 1124 PROC_LOCK(p); 1125 lim_rlimit_proc(p, RLIMIT_STACK, &rlim_stack); 1126 PROC_UNLOCK(p); 1127 if (ssiz > rlim_stack.rlim_max) 1128 ssiz = rlim_stack.rlim_max; 1129 if (ssiz > rlim_stack.rlim_cur) { 1130 rlim_stack.rlim_cur = ssiz; 1131 kern_setrlimit(curthread, RLIMIT_STACK, &rlim_stack); 1132 } 1133 } else if (sv->sv_maxssiz != NULL) { 1134 ssiz = *sv->sv_maxssiz; 1135 } else { 1136 ssiz = maxssiz; 1137 } 1138 stack_addr = sv->sv_usrstack - ssiz; 1139 error = vm_map_stack(map, stack_addr, (vm_size_t)ssiz, 1140 obj != NULL && imgp->stack_prot != 0 ? imgp->stack_prot : 1141 sv->sv_stackprot, VM_PROT_ALL, MAP_STACK_GROWS_DOWN); 1142 if (error != KERN_SUCCESS) 1143 return (vm_mmap_to_errno(error)); 1144 1145 /* 1146 * vm_ssize and vm_maxsaddr are somewhat antiquated concepts, but they 1147 * are still used to enforce the stack rlimit on the process stack. 1148 */ 1149 vmspace->vm_ssize = sgrowsiz >> PAGE_SHIFT; 1150 vmspace->vm_maxsaddr = (char *)stack_addr; 1151 1152 return (0); 1153 } 1154 1155 /* 1156 * Copy out argument and environment strings from the old process address 1157 * space into the temporary string buffer. 1158 */ 1159 int 1160 exec_copyin_args(struct image_args *args, char *fname, 1161 enum uio_seg segflg, char **argv, char **envv) 1162 { 1163 u_long argp, envp; 1164 int error; 1165 size_t length; 1166 1167 bzero(args, sizeof(*args)); 1168 if (argv == NULL) 1169 return (EFAULT); 1170 1171 /* 1172 * Allocate demand-paged memory for the file name, argument, and 1173 * environment strings. 1174 */ 1175 error = exec_alloc_args(args); 1176 if (error != 0) 1177 return (error); 1178 1179 /* 1180 * Copy the file name. 1181 */ 1182 if (fname != NULL) { 1183 args->fname = args->buf; 1184 error = (segflg == UIO_SYSSPACE) ? 1185 copystr(fname, args->fname, PATH_MAX, &length) : 1186 copyinstr(fname, args->fname, PATH_MAX, &length); 1187 if (error != 0) 1188 goto err_exit; 1189 } else 1190 length = 0; 1191 1192 args->begin_argv = args->buf + length; 1193 args->endp = args->begin_argv; 1194 args->stringspace = ARG_MAX; 1195 1196 /* 1197 * extract arguments first 1198 */ 1199 for (;;) { 1200 error = fueword(argv++, &argp); 1201 if (error == -1) { 1202 error = EFAULT; 1203 goto err_exit; 1204 } 1205 if (argp == 0) 1206 break; 1207 error = copyinstr((void *)(uintptr_t)argp, args->endp, 1208 args->stringspace, &length); 1209 if (error != 0) { 1210 if (error == ENAMETOOLONG) 1211 error = E2BIG; 1212 goto err_exit; 1213 } 1214 args->stringspace -= length; 1215 args->endp += length; 1216 args->argc++; 1217 } 1218 1219 args->begin_envv = args->endp; 1220 1221 /* 1222 * extract environment strings 1223 */ 1224 if (envv) { 1225 for (;;) { 1226 error = fueword(envv++, &envp); 1227 if (error == -1) { 1228 error = EFAULT; 1229 goto err_exit; 1230 } 1231 if (envp == 0) 1232 break; 1233 error = copyinstr((void *)(uintptr_t)envp, 1234 args->endp, args->stringspace, &length); 1235 if (error != 0) { 1236 if (error == ENAMETOOLONG) 1237 error = E2BIG; 1238 goto err_exit; 1239 } 1240 args->stringspace -= length; 1241 args->endp += length; 1242 args->envc++; 1243 } 1244 } 1245 1246 return (0); 1247 1248 err_exit: 1249 exec_free_args(args); 1250 return (error); 1251 } 1252 1253 int 1254 exec_copyin_data_fds(struct thread *td, struct image_args *args, 1255 const void *data, size_t datalen, const int *fds, size_t fdslen) 1256 { 1257 struct filedesc *ofdp; 1258 const char *p; 1259 int *kfds; 1260 int error; 1261 1262 memset(args, '\0', sizeof(*args)); 1263 ofdp = td->td_proc->p_fd; 1264 if (datalen >= ARG_MAX || fdslen > ofdp->fd_lastfile + 1) 1265 return (E2BIG); 1266 error = exec_alloc_args(args); 1267 if (error != 0) 1268 return (error); 1269 1270 args->begin_argv = args->buf; 1271 args->stringspace = ARG_MAX; 1272 1273 if (datalen > 0) { 1274 /* 1275 * Argument buffer has been provided. Copy it into the 1276 * kernel as a single string and add a terminating null 1277 * byte. 1278 */ 1279 error = copyin(data, args->begin_argv, datalen); 1280 if (error != 0) 1281 goto err_exit; 1282 args->begin_argv[datalen] = '\0'; 1283 args->endp = args->begin_argv + datalen + 1; 1284 args->stringspace -= datalen + 1; 1285 1286 /* 1287 * Traditional argument counting. Count the number of 1288 * null bytes. 1289 */ 1290 for (p = args->begin_argv; p < args->endp; ++p) 1291 if (*p == '\0') 1292 ++args->argc; 1293 } else { 1294 /* No argument buffer provided. */ 1295 args->endp = args->begin_argv; 1296 } 1297 /* There are no environment variables. */ 1298 args->begin_envv = args->endp; 1299 1300 /* Create new file descriptor table. */ 1301 kfds = malloc(fdslen * sizeof(int), M_TEMP, M_WAITOK); 1302 error = copyin(fds, kfds, fdslen * sizeof(int)); 1303 if (error != 0) { 1304 free(kfds, M_TEMP); 1305 goto err_exit; 1306 } 1307 error = fdcopy_remapped(ofdp, kfds, fdslen, &args->fdp); 1308 free(kfds, M_TEMP); 1309 if (error != 0) 1310 goto err_exit; 1311 1312 return (0); 1313 err_exit: 1314 exec_free_args(args); 1315 return (error); 1316 } 1317 1318 struct exec_args_kva { 1319 vm_offset_t addr; 1320 u_int gen; 1321 SLIST_ENTRY(exec_args_kva) next; 1322 }; 1323 1324 static DPCPU_DEFINE(struct exec_args_kva *, exec_args_kva); 1325 1326 static SLIST_HEAD(, exec_args_kva) exec_args_kva_freelist; 1327 static struct mtx exec_args_kva_mtx; 1328 static u_int exec_args_gen; 1329 1330 static void 1331 exec_prealloc_args_kva(void *arg __unused) 1332 { 1333 struct exec_args_kva *argkva; 1334 u_int i; 1335 1336 SLIST_INIT(&exec_args_kva_freelist); 1337 mtx_init(&exec_args_kva_mtx, "exec args kva", NULL, MTX_DEF); 1338 for (i = 0; i < exec_map_entries; i++) { 1339 argkva = malloc(sizeof(*argkva), M_PARGS, M_WAITOK); 1340 argkva->addr = kmap_alloc_wait(exec_map, exec_map_entry_size); 1341 argkva->gen = exec_args_gen; 1342 SLIST_INSERT_HEAD(&exec_args_kva_freelist, argkva, next); 1343 } 1344 } 1345 SYSINIT(exec_args_kva, SI_SUB_EXEC, SI_ORDER_ANY, exec_prealloc_args_kva, NULL); 1346 1347 static vm_offset_t 1348 exec_alloc_args_kva(void **cookie) 1349 { 1350 struct exec_args_kva *argkva; 1351 1352 argkva = (void *)atomic_readandclear_ptr( 1353 (uintptr_t *)DPCPU_PTR(exec_args_kva)); 1354 if (argkva == NULL) { 1355 mtx_lock(&exec_args_kva_mtx); 1356 while ((argkva = SLIST_FIRST(&exec_args_kva_freelist)) == NULL) 1357 (void)mtx_sleep(&exec_args_kva_freelist, 1358 &exec_args_kva_mtx, 0, "execkva", 0); 1359 SLIST_REMOVE_HEAD(&exec_args_kva_freelist, next); 1360 mtx_unlock(&exec_args_kva_mtx); 1361 } 1362 *(struct exec_args_kva **)cookie = argkva; 1363 return (argkva->addr); 1364 } 1365 1366 static void 1367 exec_release_args_kva(struct exec_args_kva *argkva, u_int gen) 1368 { 1369 vm_offset_t base; 1370 1371 base = argkva->addr; 1372 if (argkva->gen != gen) { 1373 vm_map_madvise(exec_map, base, base + exec_map_entry_size, 1374 MADV_FREE); 1375 argkva->gen = gen; 1376 } 1377 if (!atomic_cmpset_ptr((uintptr_t *)DPCPU_PTR(exec_args_kva), 1378 (uintptr_t)NULL, (uintptr_t)argkva)) { 1379 mtx_lock(&exec_args_kva_mtx); 1380 SLIST_INSERT_HEAD(&exec_args_kva_freelist, argkva, next); 1381 wakeup_one(&exec_args_kva_freelist); 1382 mtx_unlock(&exec_args_kva_mtx); 1383 } 1384 } 1385 1386 static void 1387 exec_free_args_kva(void *cookie) 1388 { 1389 1390 exec_release_args_kva(cookie, exec_args_gen); 1391 } 1392 1393 static void 1394 exec_args_kva_lowmem(void *arg __unused) 1395 { 1396 SLIST_HEAD(, exec_args_kva) head; 1397 struct exec_args_kva *argkva; 1398 u_int gen; 1399 int i; 1400 1401 gen = atomic_fetchadd_int(&exec_args_gen, 1) + 1; 1402 1403 /* 1404 * Force an madvise of each KVA range. Any currently allocated ranges 1405 * will have MADV_FREE applied once they are freed. 1406 */ 1407 SLIST_INIT(&head); 1408 mtx_lock(&exec_args_kva_mtx); 1409 SLIST_SWAP(&head, &exec_args_kva_freelist, exec_args_kva); 1410 mtx_unlock(&exec_args_kva_mtx); 1411 while ((argkva = SLIST_FIRST(&head)) != NULL) { 1412 SLIST_REMOVE_HEAD(&head, next); 1413 exec_release_args_kva(argkva, gen); 1414 } 1415 1416 CPU_FOREACH(i) { 1417 argkva = (void *)atomic_readandclear_ptr( 1418 (uintptr_t *)DPCPU_ID_PTR(i, exec_args_kva)); 1419 if (argkva != NULL) 1420 exec_release_args_kva(argkva, gen); 1421 } 1422 } 1423 EVENTHANDLER_DEFINE(vm_lowmem, exec_args_kva_lowmem, NULL, 1424 EVENTHANDLER_PRI_ANY); 1425 1426 /* 1427 * Allocate temporary demand-paged, zero-filled memory for the file name, 1428 * argument, and environment strings. 1429 */ 1430 int 1431 exec_alloc_args(struct image_args *args) 1432 { 1433 1434 args->buf = (char *)exec_alloc_args_kva(&args->bufkva); 1435 return (0); 1436 } 1437 1438 void 1439 exec_free_args(struct image_args *args) 1440 { 1441 1442 if (args->buf != NULL) { 1443 exec_free_args_kva(args->bufkva); 1444 args->buf = NULL; 1445 } 1446 if (args->fname_buf != NULL) { 1447 free(args->fname_buf, M_TEMP); 1448 args->fname_buf = NULL; 1449 } 1450 if (args->fdp != NULL) 1451 fdescfree_remapped(args->fdp); 1452 } 1453 1454 /* 1455 * Copy strings out to the new process address space, constructing new arg 1456 * and env vector tables. Return a pointer to the base so that it can be used 1457 * as the initial stack pointer. 1458 */ 1459 register_t * 1460 exec_copyout_strings(struct image_params *imgp) 1461 { 1462 int argc, envc; 1463 char **vectp; 1464 char *stringp; 1465 uintptr_t destp; 1466 register_t *stack_base; 1467 struct ps_strings *arginfo; 1468 struct proc *p; 1469 size_t execpath_len; 1470 int szsigcode, szps; 1471 char canary[sizeof(long) * 8]; 1472 1473 szps = sizeof(pagesizes[0]) * MAXPAGESIZES; 1474 /* 1475 * Calculate string base and vector table pointers. 1476 * Also deal with signal trampoline code for this exec type. 1477 */ 1478 if (imgp->execpath != NULL && imgp->auxargs != NULL) 1479 execpath_len = strlen(imgp->execpath) + 1; 1480 else 1481 execpath_len = 0; 1482 p = imgp->proc; 1483 szsigcode = 0; 1484 arginfo = (struct ps_strings *)p->p_sysent->sv_psstrings; 1485 if (p->p_sysent->sv_sigcode_base == 0) { 1486 if (p->p_sysent->sv_szsigcode != NULL) 1487 szsigcode = *(p->p_sysent->sv_szsigcode); 1488 } 1489 destp = (uintptr_t)arginfo; 1490 1491 /* 1492 * install sigcode 1493 */ 1494 if (szsigcode != 0) { 1495 destp -= szsigcode; 1496 destp = rounddown2(destp, sizeof(void *)); 1497 copyout(p->p_sysent->sv_sigcode, (void *)destp, szsigcode); 1498 } 1499 1500 /* 1501 * Copy the image path for the rtld. 1502 */ 1503 if (execpath_len != 0) { 1504 destp -= execpath_len; 1505 imgp->execpathp = destp; 1506 copyout(imgp->execpath, (void *)destp, execpath_len); 1507 } 1508 1509 /* 1510 * Prepare the canary for SSP. 1511 */ 1512 arc4rand(canary, sizeof(canary), 0); 1513 destp -= sizeof(canary); 1514 imgp->canary = destp; 1515 copyout(canary, (void *)destp, sizeof(canary)); 1516 imgp->canarylen = sizeof(canary); 1517 1518 /* 1519 * Prepare the pagesizes array. 1520 */ 1521 destp -= szps; 1522 destp = rounddown2(destp, sizeof(void *)); 1523 imgp->pagesizes = destp; 1524 copyout(pagesizes, (void *)destp, szps); 1525 imgp->pagesizeslen = szps; 1526 1527 destp -= ARG_MAX - imgp->args->stringspace; 1528 destp = rounddown2(destp, sizeof(void *)); 1529 1530 /* 1531 * If we have a valid auxargs ptr, prepare some room 1532 * on the stack. 1533 */ 1534 if (imgp->auxargs) { 1535 /* 1536 * 'AT_COUNT*2' is size for the ELF Auxargs data. This is for 1537 * lower compatibility. 1538 */ 1539 imgp->auxarg_size = (imgp->auxarg_size) ? imgp->auxarg_size : 1540 (AT_COUNT * 2); 1541 /* 1542 * The '+ 2' is for the null pointers at the end of each of 1543 * the arg and env vector sets,and imgp->auxarg_size is room 1544 * for argument of Runtime loader. 1545 */ 1546 vectp = (char **)(destp - (imgp->args->argc + 1547 imgp->args->envc + 2 + imgp->auxarg_size) 1548 * sizeof(char *)); 1549 } else { 1550 /* 1551 * The '+ 2' is for the null pointers at the end of each of 1552 * the arg and env vector sets 1553 */ 1554 vectp = (char **)(destp - (imgp->args->argc + imgp->args->envc 1555 + 2) * sizeof(char *)); 1556 } 1557 1558 /* 1559 * vectp also becomes our initial stack base 1560 */ 1561 stack_base = (register_t *)vectp; 1562 1563 stringp = imgp->args->begin_argv; 1564 argc = imgp->args->argc; 1565 envc = imgp->args->envc; 1566 1567 /* 1568 * Copy out strings - arguments and environment. 1569 */ 1570 copyout(stringp, (void *)destp, ARG_MAX - imgp->args->stringspace); 1571 1572 /* 1573 * Fill in "ps_strings" struct for ps, w, etc. 1574 */ 1575 suword(&arginfo->ps_argvstr, (long)(intptr_t)vectp); 1576 suword32(&arginfo->ps_nargvstr, argc); 1577 1578 /* 1579 * Fill in argument portion of vector table. 1580 */ 1581 for (; argc > 0; --argc) { 1582 suword(vectp++, (long)(intptr_t)destp); 1583 while (*stringp++ != 0) 1584 destp++; 1585 destp++; 1586 } 1587 1588 /* a null vector table pointer separates the argp's from the envp's */ 1589 suword(vectp++, 0); 1590 1591 suword(&arginfo->ps_envstr, (long)(intptr_t)vectp); 1592 suword32(&arginfo->ps_nenvstr, envc); 1593 1594 /* 1595 * Fill in environment portion of vector table. 1596 */ 1597 for (; envc > 0; --envc) { 1598 suword(vectp++, (long)(intptr_t)destp); 1599 while (*stringp++ != 0) 1600 destp++; 1601 destp++; 1602 } 1603 1604 /* end of vector table is a null pointer */ 1605 suword(vectp, 0); 1606 1607 return (stack_base); 1608 } 1609 1610 /* 1611 * Check permissions of file to execute. 1612 * Called with imgp->vp locked. 1613 * Return 0 for success or error code on failure. 1614 */ 1615 int 1616 exec_check_permissions(struct image_params *imgp) 1617 { 1618 struct vnode *vp = imgp->vp; 1619 struct vattr *attr = imgp->attr; 1620 struct thread *td; 1621 int error, writecount; 1622 1623 td = curthread; 1624 1625 /* Get file attributes */ 1626 error = VOP_GETATTR(vp, attr, td->td_ucred); 1627 if (error) 1628 return (error); 1629 1630 #ifdef MAC 1631 error = mac_vnode_check_exec(td->td_ucred, imgp->vp, imgp); 1632 if (error) 1633 return (error); 1634 #endif 1635 1636 /* 1637 * 1) Check if file execution is disabled for the filesystem that 1638 * this file resides on. 1639 * 2) Ensure that at least one execute bit is on. Otherwise, a 1640 * privileged user will always succeed, and we don't want this 1641 * to happen unless the file really is executable. 1642 * 3) Ensure that the file is a regular file. 1643 */ 1644 if ((vp->v_mount->mnt_flag & MNT_NOEXEC) || 1645 (attr->va_mode & (S_IXUSR | S_IXGRP | S_IXOTH)) == 0 || 1646 (attr->va_type != VREG)) 1647 return (EACCES); 1648 1649 /* 1650 * Zero length files can't be exec'd 1651 */ 1652 if (attr->va_size == 0) 1653 return (ENOEXEC); 1654 1655 /* 1656 * Check for execute permission to file based on current credentials. 1657 */ 1658 error = VOP_ACCESS(vp, VEXEC, td->td_ucred, td); 1659 if (error) 1660 return (error); 1661 1662 /* 1663 * Check number of open-for-writes on the file and deny execution 1664 * if there are any. 1665 */ 1666 error = VOP_GET_WRITECOUNT(vp, &writecount); 1667 if (error != 0) 1668 return (error); 1669 if (writecount != 0) 1670 return (ETXTBSY); 1671 1672 /* 1673 * Call filesystem specific open routine (which does nothing in the 1674 * general case). 1675 */ 1676 error = VOP_OPEN(vp, FREAD, td->td_ucred, td, NULL); 1677 if (error == 0) 1678 imgp->opened = 1; 1679 return (error); 1680 } 1681 1682 /* 1683 * Exec handler registration 1684 */ 1685 int 1686 exec_register(const struct execsw *execsw_arg) 1687 { 1688 const struct execsw **es, **xs, **newexecsw; 1689 int count = 2; /* New slot and trailing NULL */ 1690 1691 if (execsw) 1692 for (es = execsw; *es; es++) 1693 count++; 1694 newexecsw = malloc(count * sizeof(*es), M_TEMP, M_WAITOK); 1695 xs = newexecsw; 1696 if (execsw) 1697 for (es = execsw; *es; es++) 1698 *xs++ = *es; 1699 *xs++ = execsw_arg; 1700 *xs = NULL; 1701 if (execsw) 1702 free(execsw, M_TEMP); 1703 execsw = newexecsw; 1704 return (0); 1705 } 1706 1707 int 1708 exec_unregister(const struct execsw *execsw_arg) 1709 { 1710 const struct execsw **es, **xs, **newexecsw; 1711 int count = 1; 1712 1713 if (execsw == NULL) 1714 panic("unregister with no handlers left?\n"); 1715 1716 for (es = execsw; *es; es++) { 1717 if (*es == execsw_arg) 1718 break; 1719 } 1720 if (*es == NULL) 1721 return (ENOENT); 1722 for (es = execsw; *es; es++) 1723 if (*es != execsw_arg) 1724 count++; 1725 newexecsw = malloc(count * sizeof(*es), M_TEMP, M_WAITOK); 1726 xs = newexecsw; 1727 for (es = execsw; *es; es++) 1728 if (*es != execsw_arg) 1729 *xs++ = *es; 1730 *xs = NULL; 1731 if (execsw) 1732 free(execsw, M_TEMP); 1733 execsw = newexecsw; 1734 return (0); 1735 } 1736