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_hwpmc_hooks.h" 31 #include "opt_ktrace.h" 32 #include "opt_mac.h" 33 34 #include <sys/param.h> 35 #include <sys/systm.h> 36 #include <sys/eventhandler.h> 37 #include <sys/lock.h> 38 #include <sys/mutex.h> 39 #include <sys/sysproto.h> 40 #include <sys/signalvar.h> 41 #include <sys/kernel.h> 42 #include <sys/mount.h> 43 #include <sys/filedesc.h> 44 #include <sys/fcntl.h> 45 #include <sys/acct.h> 46 #include <sys/exec.h> 47 #include <sys/imgact.h> 48 #include <sys/imgact_elf.h> 49 #include <sys/wait.h> 50 #include <sys/malloc.h> 51 #include <sys/priv.h> 52 #include <sys/proc.h> 53 #include <sys/pioctl.h> 54 #include <sys/namei.h> 55 #include <sys/resourcevar.h> 56 #include <sys/sf_buf.h> 57 #include <sys/syscallsubr.h> 58 #include <sys/sysent.h> 59 #include <sys/shm.h> 60 #include <sys/sysctl.h> 61 #include <sys/vnode.h> 62 #ifdef KTRACE 63 #include <sys/ktrace.h> 64 #endif 65 66 #include <vm/vm.h> 67 #include <vm/vm_param.h> 68 #include <vm/pmap.h> 69 #include <vm/vm_page.h> 70 #include <vm/vm_map.h> 71 #include <vm/vm_kern.h> 72 #include <vm/vm_extern.h> 73 #include <vm/vm_object.h> 74 #include <vm/vm_pager.h> 75 76 #ifdef HWPMC_HOOKS 77 #include <sys/pmckern.h> 78 #endif 79 80 #include <machine/reg.h> 81 82 #include <security/audit/audit.h> 83 #include <security/mac/mac_framework.h> 84 85 MALLOC_DEFINE(M_PARGS, "proc-args", "Process arguments"); 86 87 static int sysctl_kern_ps_strings(SYSCTL_HANDLER_ARGS); 88 static int sysctl_kern_usrstack(SYSCTL_HANDLER_ARGS); 89 static int sysctl_kern_stackprot(SYSCTL_HANDLER_ARGS); 90 static int do_execve(struct thread *td, struct image_args *args, 91 struct mac *mac_p); 92 static void exec_free_args(struct image_args *); 93 94 /* XXX This should be vm_size_t. */ 95 SYSCTL_PROC(_kern, KERN_PS_STRINGS, ps_strings, CTLTYPE_ULONG|CTLFLAG_RD, 96 NULL, 0, sysctl_kern_ps_strings, "LU", ""); 97 98 /* XXX This should be vm_size_t. */ 99 SYSCTL_PROC(_kern, KERN_USRSTACK, usrstack, CTLTYPE_ULONG|CTLFLAG_RD, 100 NULL, 0, sysctl_kern_usrstack, "LU", ""); 101 102 SYSCTL_PROC(_kern, OID_AUTO, stackprot, CTLTYPE_INT|CTLFLAG_RD, 103 NULL, 0, sysctl_kern_stackprot, "I", ""); 104 105 u_long ps_arg_cache_limit = PAGE_SIZE / 16; 106 SYSCTL_ULONG(_kern, OID_AUTO, ps_arg_cache_limit, CTLFLAG_RW, 107 &ps_arg_cache_limit, 0, ""); 108 109 static int 110 sysctl_kern_ps_strings(SYSCTL_HANDLER_ARGS) 111 { 112 struct proc *p; 113 int error; 114 115 p = curproc; 116 #ifdef SCTL_MASK32 117 if (req->flags & SCTL_MASK32) { 118 unsigned int val; 119 val = (unsigned int)p->p_sysent->sv_psstrings; 120 error = SYSCTL_OUT(req, &val, sizeof(val)); 121 } else 122 #endif 123 error = SYSCTL_OUT(req, &p->p_sysent->sv_psstrings, 124 sizeof(p->p_sysent->sv_psstrings)); 125 return error; 126 } 127 128 static int 129 sysctl_kern_usrstack(SYSCTL_HANDLER_ARGS) 130 { 131 struct proc *p; 132 int error; 133 134 p = curproc; 135 #ifdef SCTL_MASK32 136 if (req->flags & SCTL_MASK32) { 137 unsigned int val; 138 val = (unsigned int)p->p_sysent->sv_usrstack; 139 error = SYSCTL_OUT(req, &val, sizeof(val)); 140 } else 141 #endif 142 error = SYSCTL_OUT(req, &p->p_sysent->sv_usrstack, 143 sizeof(p->p_sysent->sv_usrstack)); 144 return error; 145 } 146 147 static int 148 sysctl_kern_stackprot(SYSCTL_HANDLER_ARGS) 149 { 150 struct proc *p; 151 152 p = curproc; 153 return (SYSCTL_OUT(req, &p->p_sysent->sv_stackprot, 154 sizeof(p->p_sysent->sv_stackprot))); 155 } 156 157 /* 158 * Each of the items is a pointer to a `const struct execsw', hence the 159 * double pointer here. 160 */ 161 static const struct execsw **execsw; 162 163 #ifndef _SYS_SYSPROTO_H_ 164 struct execve_args { 165 char *fname; 166 char **argv; 167 char **envv; 168 }; 169 #endif 170 171 int 172 execve(td, uap) 173 struct thread *td; 174 struct execve_args /* { 175 char *fname; 176 char **argv; 177 char **envv; 178 } */ *uap; 179 { 180 int error; 181 struct image_args args; 182 183 error = exec_copyin_args(&args, uap->fname, UIO_USERSPACE, 184 uap->argv, uap->envv); 185 if (error == 0) 186 error = kern_execve(td, &args, NULL); 187 return (error); 188 } 189 190 #ifndef _SYS_SYSPROTO_H_ 191 struct __mac_execve_args { 192 char *fname; 193 char **argv; 194 char **envv; 195 struct mac *mac_p; 196 }; 197 #endif 198 199 int 200 __mac_execve(td, uap) 201 struct thread *td; 202 struct __mac_execve_args /* { 203 char *fname; 204 char **argv; 205 char **envv; 206 struct mac *mac_p; 207 } */ *uap; 208 { 209 #ifdef MAC 210 int error; 211 struct image_args args; 212 213 error = exec_copyin_args(&args, uap->fname, UIO_USERSPACE, 214 uap->argv, uap->envv); 215 if (error == 0) 216 error = kern_execve(td, &args, uap->mac_p); 217 return (error); 218 #else 219 return (ENOSYS); 220 #endif 221 } 222 223 /* 224 * XXX: kern_execve has the astonishing property of not always returning to 225 * the caller. If sufficiently bad things happen during the call to 226 * do_execve(), it can end up calling exit1(); as a result, callers must 227 * avoid doing anything which they might need to undo (e.g., allocating 228 * memory). 229 */ 230 int 231 kern_execve(td, args, mac_p) 232 struct thread *td; 233 struct image_args *args; 234 struct mac *mac_p; 235 { 236 struct proc *p = td->td_proc; 237 int error; 238 239 AUDIT_ARG(argv, args->begin_argv, args->argc, 240 args->begin_envv - args->begin_argv); 241 AUDIT_ARG(envv, args->begin_envv, args->envc, 242 args->endp - args->begin_envv); 243 if (p->p_flag & P_HADTHREADS) { 244 PROC_LOCK(p); 245 if (thread_single(SINGLE_BOUNDARY)) { 246 PROC_UNLOCK(p); 247 exec_free_args(args); 248 return (ERESTART); /* Try again later. */ 249 } 250 PROC_UNLOCK(p); 251 } 252 253 error = do_execve(td, args, mac_p); 254 255 if (p->p_flag & P_HADTHREADS) { 256 PROC_LOCK(p); 257 /* 258 * If success, we upgrade to SINGLE_EXIT state to 259 * force other threads to suicide. 260 */ 261 if (error == 0) 262 thread_single(SINGLE_EXIT); 263 else 264 thread_single_end(); 265 PROC_UNLOCK(p); 266 } 267 268 return (error); 269 } 270 271 /* 272 * In-kernel implementation of execve(). All arguments are assumed to be 273 * userspace pointers from the passed thread. 274 */ 275 static int 276 do_execve(td, args, mac_p) 277 struct thread *td; 278 struct image_args *args; 279 struct mac *mac_p; 280 { 281 struct proc *p = td->td_proc; 282 struct nameidata nd, *ndp; 283 struct ucred *newcred = NULL, *oldcred; 284 struct uidinfo *euip; 285 register_t *stack_base; 286 int error, len, i; 287 struct image_params image_params, *imgp; 288 struct vattr attr; 289 int (*img_first)(struct image_params *); 290 struct pargs *oldargs = NULL, *newargs = NULL; 291 struct sigacts *oldsigacts, *newsigacts; 292 #ifdef KTRACE 293 struct vnode *tracevp = NULL; 294 struct ucred *tracecred = NULL; 295 #endif 296 struct vnode *textvp = NULL; 297 int credential_changing; 298 int vfslocked; 299 int textset; 300 #ifdef MAC 301 struct label *interplabel = NULL; 302 int will_transition; 303 #endif 304 #ifdef HWPMC_HOOKS 305 struct pmckern_procexec pe; 306 #endif 307 308 vfslocked = 0; 309 imgp = &image_params; 310 311 /* 312 * Lock the process and set the P_INEXEC flag to indicate that 313 * it should be left alone until we're done here. This is 314 * necessary to avoid race conditions - e.g. in ptrace() - 315 * that might allow a local user to illicitly obtain elevated 316 * privileges. 317 */ 318 PROC_LOCK(p); 319 KASSERT((p->p_flag & P_INEXEC) == 0, 320 ("%s(): process already has P_INEXEC flag", __func__)); 321 p->p_flag |= P_INEXEC; 322 PROC_UNLOCK(p); 323 324 /* 325 * Initialize part of the common data 326 */ 327 imgp->proc = p; 328 imgp->execlabel = NULL; 329 imgp->attr = &attr; 330 imgp->entry_addr = 0; 331 imgp->vmspace_destroyed = 0; 332 imgp->interpreted = 0; 333 imgp->interpreter_name = args->buf + PATH_MAX + ARG_MAX; 334 imgp->auxargs = NULL; 335 imgp->vp = NULL; 336 imgp->object = NULL; 337 imgp->firstpage = NULL; 338 imgp->ps_strings = 0; 339 imgp->auxarg_size = 0; 340 imgp->args = args; 341 342 #ifdef MAC 343 error = mac_execve_enter(imgp, mac_p); 344 if (error) 345 goto exec_fail; 346 #endif 347 348 imgp->image_header = NULL; 349 350 /* 351 * Translate the file name. namei() returns a vnode pointer 352 * in ni_vp amoung other things. 353 * 354 * XXXAUDIT: It would be desirable to also audit the name of the 355 * interpreter if this is an interpreted binary. 356 */ 357 ndp = &nd; 358 NDINIT(ndp, LOOKUP, ISOPEN | LOCKLEAF | FOLLOW | SAVENAME | MPSAFE | 359 AUDITVNODE1, UIO_SYSSPACE, args->fname, td); 360 361 interpret: 362 error = namei(ndp); 363 if (error) 364 goto exec_fail; 365 366 vfslocked = NDHASGIANT(ndp); 367 imgp->vp = ndp->ni_vp; 368 369 /* 370 * Check file permissions (also 'opens' file) 371 */ 372 error = exec_check_permissions(imgp); 373 if (error) 374 goto exec_fail_dealloc; 375 376 imgp->object = imgp->vp->v_object; 377 if (imgp->object != NULL) 378 vm_object_reference(imgp->object); 379 380 /* 381 * Set VV_TEXT now so no one can write to the executable while we're 382 * activating it. 383 * 384 * Remember if this was set before and unset it in case this is not 385 * actually an executable image. 386 */ 387 textset = imgp->vp->v_vflag & VV_TEXT; 388 imgp->vp->v_vflag |= VV_TEXT; 389 390 error = exec_map_first_page(imgp); 391 if (error) 392 goto exec_fail_dealloc; 393 394 imgp->proc->p_osrel = 0; 395 /* 396 * If the current process has a special image activator it 397 * wants to try first, call it. For example, emulating shell 398 * scripts differently. 399 */ 400 error = -1; 401 if ((img_first = imgp->proc->p_sysent->sv_imgact_try) != NULL) 402 error = img_first(imgp); 403 404 /* 405 * Loop through the list of image activators, calling each one. 406 * An activator returns -1 if there is no match, 0 on success, 407 * and an error otherwise. 408 */ 409 for (i = 0; error == -1 && execsw[i]; ++i) { 410 if (execsw[i]->ex_imgact == NULL || 411 execsw[i]->ex_imgact == img_first) { 412 continue; 413 } 414 error = (*execsw[i]->ex_imgact)(imgp); 415 } 416 417 if (error) { 418 if (error == -1) { 419 if (textset == 0) 420 imgp->vp->v_vflag &= ~VV_TEXT; 421 error = ENOEXEC; 422 } 423 goto exec_fail_dealloc; 424 } 425 426 /* 427 * Special interpreter operation, cleanup and loop up to try to 428 * activate the interpreter. 429 */ 430 if (imgp->interpreted) { 431 exec_unmap_first_page(imgp); 432 /* 433 * VV_TEXT needs to be unset for scripts. There is a short 434 * period before we determine that something is a script where 435 * VV_TEXT will be set. The vnode lock is held over this 436 * entire period so nothing should illegitimately be blocked. 437 */ 438 imgp->vp->v_vflag &= ~VV_TEXT; 439 /* free name buffer and old vnode */ 440 NDFREE(ndp, NDF_ONLY_PNBUF); 441 #ifdef MAC 442 interplabel = mac_vnode_label_alloc(); 443 mac_vnode_copy_label(ndp->ni_vp->v_label, interplabel); 444 #endif 445 vput(ndp->ni_vp); 446 vm_object_deallocate(imgp->object); 447 imgp->object = NULL; 448 VFS_UNLOCK_GIANT(vfslocked); 449 vfslocked = 0; 450 /* set new name to that of the interpreter */ 451 NDINIT(ndp, LOOKUP, LOCKLEAF | FOLLOW | SAVENAME | MPSAFE, 452 UIO_SYSSPACE, imgp->interpreter_name, td); 453 goto interpret; 454 } 455 456 /* 457 * Copy out strings (args and env) and initialize stack base 458 */ 459 if (p->p_sysent->sv_copyout_strings) 460 stack_base = (*p->p_sysent->sv_copyout_strings)(imgp); 461 else 462 stack_base = exec_copyout_strings(imgp); 463 464 /* 465 * If custom stack fixup routine present for this process 466 * let it do the stack setup. 467 * Else stuff argument count as first item on stack 468 */ 469 if (p->p_sysent->sv_fixup != NULL) 470 (*p->p_sysent->sv_fixup)(&stack_base, imgp); 471 else 472 suword(--stack_base, imgp->args->argc); 473 474 /* 475 * For security and other reasons, the file descriptor table cannot 476 * be shared after an exec. 477 */ 478 fdunshare(p, td); 479 480 /* 481 * Malloc things before we need locks. 482 */ 483 newcred = crget(); 484 euip = uifind(attr.va_uid); 485 i = imgp->args->begin_envv - imgp->args->begin_argv; 486 /* Cache arguments if they fit inside our allowance */ 487 if (ps_arg_cache_limit >= i + sizeof(struct pargs)) { 488 newargs = pargs_alloc(i); 489 bcopy(imgp->args->begin_argv, newargs->ar_args, i); 490 } 491 492 /* close files on exec */ 493 VOP_UNLOCK(imgp->vp, 0, td); 494 fdcloseexec(td); 495 vn_lock(imgp->vp, LK_EXCLUSIVE | LK_RETRY, td); 496 497 /* Get a reference to the vnode prior to locking the proc */ 498 VREF(ndp->ni_vp); 499 500 /* 501 * For security and other reasons, signal handlers cannot 502 * be shared after an exec. The new process gets a copy of the old 503 * handlers. In execsigs(), the new process will have its signals 504 * reset. 505 */ 506 PROC_LOCK(p); 507 if (sigacts_shared(p->p_sigacts)) { 508 oldsigacts = p->p_sigacts; 509 PROC_UNLOCK(p); 510 newsigacts = sigacts_alloc(); 511 sigacts_copy(newsigacts, oldsigacts); 512 PROC_LOCK(p); 513 p->p_sigacts = newsigacts; 514 } else 515 oldsigacts = NULL; 516 517 /* Stop profiling */ 518 stopprofclock(p); 519 520 /* reset caught signals */ 521 execsigs(p); 522 523 /* name this process - nameiexec(p, ndp) */ 524 len = min(ndp->ni_cnd.cn_namelen,MAXCOMLEN); 525 bcopy(ndp->ni_cnd.cn_nameptr, p->p_comm, len); 526 p->p_comm[len] = 0; 527 bcopy(p->p_comm, td->td_name, sizeof(td->td_name)); 528 529 /* 530 * mark as execed, wakeup the process that vforked (if any) and tell 531 * it that it now has its own resources back 532 */ 533 p->p_flag |= P_EXEC; 534 if (p->p_pptr && (p->p_flag & P_PPWAIT)) { 535 p->p_flag &= ~P_PPWAIT; 536 wakeup(p->p_pptr); 537 } 538 539 /* 540 * Implement image setuid/setgid. 541 * 542 * Don't honor setuid/setgid if the filesystem prohibits it or if 543 * the process is being traced. 544 * 545 * XXXMAC: For the time being, use NOSUID to also prohibit 546 * transitions on the file system. 547 */ 548 oldcred = p->p_ucred; 549 credential_changing = 0; 550 credential_changing |= (attr.va_mode & VSUID) && oldcred->cr_uid != 551 attr.va_uid; 552 credential_changing |= (attr.va_mode & VSGID) && oldcred->cr_gid != 553 attr.va_gid; 554 #ifdef MAC 555 will_transition = mac_vnode_execve_will_transition(oldcred, imgp->vp, 556 interplabel, imgp); 557 credential_changing |= will_transition; 558 #endif 559 560 if (credential_changing && 561 (imgp->vp->v_mount->mnt_flag & MNT_NOSUID) == 0 && 562 (p->p_flag & P_TRACED) == 0) { 563 /* 564 * Turn off syscall tracing for set-id programs, except for 565 * root. Record any set-id flags first to make sure that 566 * we do not regain any tracing during a possible block. 567 */ 568 setsugid(p); 569 570 #ifdef KTRACE 571 if (p->p_tracevp != NULL && 572 priv_check_cred(oldcred, PRIV_DEBUG_DIFFCRED, 0)) { 573 mtx_lock(&ktrace_mtx); 574 p->p_traceflag = 0; 575 tracevp = p->p_tracevp; 576 p->p_tracevp = NULL; 577 tracecred = p->p_tracecred; 578 p->p_tracecred = NULL; 579 mtx_unlock(&ktrace_mtx); 580 } 581 #endif 582 /* 583 * Close any file descriptors 0..2 that reference procfs, 584 * then make sure file descriptors 0..2 are in use. 585 * 586 * setugidsafety() may call closef() and then pfind() 587 * which may grab the process lock. 588 * fdcheckstd() may call falloc() which may block to 589 * allocate memory, so temporarily drop the process lock. 590 */ 591 PROC_UNLOCK(p); 592 setugidsafety(td); 593 VOP_UNLOCK(imgp->vp, 0, td); 594 error = fdcheckstd(td); 595 vn_lock(imgp->vp, LK_EXCLUSIVE | LK_RETRY, td); 596 if (error != 0) 597 goto done1; 598 PROC_LOCK(p); 599 /* 600 * Set the new credentials. 601 */ 602 crcopy(newcred, oldcred); 603 if (attr.va_mode & VSUID) 604 change_euid(newcred, euip); 605 if (attr.va_mode & VSGID) 606 change_egid(newcred, attr.va_gid); 607 #ifdef MAC 608 if (will_transition) { 609 mac_vnode_execve_transition(oldcred, newcred, imgp->vp, 610 interplabel, imgp); 611 } 612 #endif 613 /* 614 * Implement correct POSIX saved-id behavior. 615 * 616 * XXXMAC: Note that the current logic will save the 617 * uid and gid if a MAC domain transition occurs, even 618 * though maybe it shouldn't. 619 */ 620 change_svuid(newcred, newcred->cr_uid); 621 change_svgid(newcred, newcred->cr_gid); 622 p->p_ucred = newcred; 623 newcred = NULL; 624 } else { 625 if (oldcred->cr_uid == oldcred->cr_ruid && 626 oldcred->cr_gid == oldcred->cr_rgid) 627 p->p_flag &= ~P_SUGID; 628 /* 629 * Implement correct POSIX saved-id behavior. 630 * 631 * XXX: It's not clear that the existing behavior is 632 * POSIX-compliant. A number of sources indicate that the 633 * saved uid/gid should only be updated if the new ruid is 634 * not equal to the old ruid, or the new euid is not equal 635 * to the old euid and the new euid is not equal to the old 636 * ruid. The FreeBSD code always updates the saved uid/gid. 637 * Also, this code uses the new (replaced) euid and egid as 638 * the source, which may or may not be the right ones to use. 639 */ 640 if (oldcred->cr_svuid != oldcred->cr_uid || 641 oldcred->cr_svgid != oldcred->cr_gid) { 642 crcopy(newcred, oldcred); 643 change_svuid(newcred, newcred->cr_uid); 644 change_svgid(newcred, newcred->cr_gid); 645 p->p_ucred = newcred; 646 newcred = NULL; 647 } 648 } 649 650 /* 651 * Store the vp for use in procfs. This vnode was referenced prior 652 * to locking the proc lock. 653 */ 654 textvp = p->p_textvp; 655 p->p_textvp = ndp->ni_vp; 656 657 /* 658 * Notify others that we exec'd, and clear the P_INEXEC flag 659 * as we're now a bona fide freshly-execed process. 660 */ 661 KNOTE_LOCKED(&p->p_klist, NOTE_EXEC); 662 p->p_flag &= ~P_INEXEC; 663 664 /* 665 * If tracing the process, trap to debugger so breakpoints 666 * can be set before the program executes. 667 * Use tdsignal to deliver signal to current thread, use 668 * psignal may cause the signal to be delivered to wrong thread 669 * because that thread will exit, remember we are going to enter 670 * single thread mode. 671 */ 672 if (p->p_flag & P_TRACED) 673 tdsignal(p, td, SIGTRAP, NULL); 674 675 /* clear "fork but no exec" flag, as we _are_ execing */ 676 p->p_acflag &= ~AFORK; 677 678 /* 679 * Free any previous argument cache and replace it with 680 * the new argument cache, if any. 681 */ 682 oldargs = p->p_args; 683 p->p_args = newargs; 684 newargs = NULL; 685 686 #ifdef HWPMC_HOOKS 687 /* 688 * Check if system-wide sampling is in effect or if the 689 * current process is using PMCs. If so, do exec() time 690 * processing. This processing needs to happen AFTER the 691 * P_INEXEC flag is cleared. 692 * 693 * The proc lock needs to be released before taking the PMC 694 * SX. 695 */ 696 if (PMC_SYSTEM_SAMPLING_ACTIVE() || PMC_PROC_IS_USING_PMCS(p)) { 697 PROC_UNLOCK(p); 698 pe.pm_credentialschanged = credential_changing; 699 pe.pm_entryaddr = imgp->entry_addr; 700 701 PMC_CALL_HOOK_X(td, PMC_FN_PROCESS_EXEC, (void *) &pe); 702 } else 703 PROC_UNLOCK(p); 704 #else /* !HWPMC_HOOKS */ 705 PROC_UNLOCK(p); 706 #endif 707 708 /* Set values passed into the program in registers. */ 709 if (p->p_sysent->sv_setregs) 710 (*p->p_sysent->sv_setregs)(td, imgp->entry_addr, 711 (u_long)(uintptr_t)stack_base, imgp->ps_strings); 712 else 713 exec_setregs(td, imgp->entry_addr, 714 (u_long)(uintptr_t)stack_base, imgp->ps_strings); 715 716 vfs_mark_atime(imgp->vp, td); 717 718 done1: 719 /* 720 * Free any resources malloc'd earlier that we didn't use. 721 */ 722 uifree(euip); 723 if (newcred == NULL) 724 crfree(oldcred); 725 else 726 crfree(newcred); 727 VOP_UNLOCK(imgp->vp, 0, td); 728 /* 729 * Handle deferred decrement of ref counts. 730 */ 731 if (textvp != NULL) { 732 int tvfslocked; 733 734 tvfslocked = VFS_LOCK_GIANT(textvp->v_mount); 735 vrele(textvp); 736 VFS_UNLOCK_GIANT(tvfslocked); 737 } 738 if (ndp->ni_vp && error != 0) 739 vrele(ndp->ni_vp); 740 #ifdef KTRACE 741 if (tracevp != NULL) { 742 int tvfslocked; 743 744 tvfslocked = VFS_LOCK_GIANT(tracevp->v_mount); 745 vrele(tracevp); 746 VFS_UNLOCK_GIANT(tvfslocked); 747 } 748 if (tracecred != NULL) 749 crfree(tracecred); 750 #endif 751 vn_lock(imgp->vp, LK_EXCLUSIVE | LK_RETRY, td); 752 if (oldargs != NULL) 753 pargs_drop(oldargs); 754 if (newargs != NULL) 755 pargs_drop(newargs); 756 if (oldsigacts != NULL) 757 sigacts_free(oldsigacts); 758 759 exec_fail_dealloc: 760 761 /* 762 * free various allocated resources 763 */ 764 if (imgp->firstpage != NULL) 765 exec_unmap_first_page(imgp); 766 767 if (imgp->vp != NULL) { 768 NDFREE(ndp, NDF_ONLY_PNBUF); 769 vput(imgp->vp); 770 } 771 772 if (imgp->object != NULL) 773 vm_object_deallocate(imgp->object); 774 775 if (error == 0) { 776 /* 777 * Stop the process here if its stop event mask has 778 * the S_EXEC bit set. 779 */ 780 STOPEVENT(p, S_EXEC, 0); 781 goto done2; 782 } 783 784 exec_fail: 785 /* we're done here, clear P_INEXEC */ 786 PROC_LOCK(p); 787 p->p_flag &= ~P_INEXEC; 788 PROC_UNLOCK(p); 789 790 done2: 791 #ifdef MAC 792 mac_execve_exit(imgp); 793 if (interplabel != NULL) 794 mac_vnode_label_free(interplabel); 795 #endif 796 VFS_UNLOCK_GIANT(vfslocked); 797 exec_free_args(args); 798 799 if (error && imgp->vmspace_destroyed) { 800 /* sorry, no more process anymore. exit gracefully */ 801 exit1(td, W_EXITCODE(0, SIGABRT)); 802 /* NOT REACHED */ 803 } 804 return (error); 805 } 806 807 int 808 exec_map_first_page(imgp) 809 struct image_params *imgp; 810 { 811 int rv, i; 812 int initial_pagein; 813 vm_page_t ma[VM_INITIAL_PAGEIN]; 814 vm_object_t object; 815 816 if (imgp->firstpage != NULL) 817 exec_unmap_first_page(imgp); 818 819 object = imgp->vp->v_object; 820 if (object == NULL) 821 return (EACCES); 822 VM_OBJECT_LOCK(object); 823 ma[0] = vm_page_grab(object, 0, VM_ALLOC_NORMAL | VM_ALLOC_RETRY); 824 if ((ma[0]->valid & VM_PAGE_BITS_ALL) != VM_PAGE_BITS_ALL) { 825 initial_pagein = VM_INITIAL_PAGEIN; 826 if (initial_pagein > object->size) 827 initial_pagein = object->size; 828 for (i = 1; i < initial_pagein; i++) { 829 if ((ma[i] = vm_page_lookup(object, i)) != NULL) { 830 if (ma[i]->valid) 831 break; 832 if ((ma[i]->oflags & VPO_BUSY) || ma[i]->busy) 833 break; 834 vm_page_busy(ma[i]); 835 } else { 836 ma[i] = vm_page_alloc(object, i, 837 VM_ALLOC_NORMAL | VM_ALLOC_IFNOTCACHED); 838 if (ma[i] == NULL) 839 break; 840 } 841 } 842 initial_pagein = i; 843 rv = vm_pager_get_pages(object, ma, initial_pagein, 0); 844 ma[0] = vm_page_lookup(object, 0); 845 if ((rv != VM_PAGER_OK) || (ma[0] == NULL) || 846 (ma[0]->valid == 0)) { 847 if (ma[0]) { 848 vm_page_lock_queues(); 849 vm_page_free(ma[0]); 850 vm_page_unlock_queues(); 851 } 852 VM_OBJECT_UNLOCK(object); 853 return (EIO); 854 } 855 } 856 vm_page_lock_queues(); 857 vm_page_hold(ma[0]); 858 vm_page_unlock_queues(); 859 vm_page_wakeup(ma[0]); 860 VM_OBJECT_UNLOCK(object); 861 862 imgp->firstpage = sf_buf_alloc(ma[0], 0); 863 imgp->image_header = (char *)sf_buf_kva(imgp->firstpage); 864 865 return (0); 866 } 867 868 void 869 exec_unmap_first_page(imgp) 870 struct image_params *imgp; 871 { 872 vm_page_t m; 873 874 if (imgp->firstpage != NULL) { 875 m = sf_buf_page(imgp->firstpage); 876 sf_buf_free(imgp->firstpage); 877 imgp->firstpage = NULL; 878 vm_page_lock_queues(); 879 vm_page_unhold(m); 880 vm_page_unlock_queues(); 881 } 882 } 883 884 /* 885 * Destroy old address space, and allocate a new stack 886 * The new stack is only SGROWSIZ large because it is grown 887 * automatically in trap.c. 888 */ 889 int 890 exec_new_vmspace(imgp, sv) 891 struct image_params *imgp; 892 struct sysentvec *sv; 893 { 894 int error; 895 struct proc *p = imgp->proc; 896 struct vmspace *vmspace = p->p_vmspace; 897 vm_offset_t stack_addr; 898 vm_map_t map; 899 u_long ssiz; 900 901 imgp->vmspace_destroyed = 1; 902 imgp->sysent = sv; 903 904 /* May be called with Giant held */ 905 EVENTHANDLER_INVOKE(process_exec, p, imgp); 906 907 /* 908 * Blow away entire process VM, if address space not shared, 909 * otherwise, create a new VM space so that other threads are 910 * not disrupted 911 */ 912 map = &vmspace->vm_map; 913 if (vmspace->vm_refcnt == 1 && vm_map_min(map) == sv->sv_minuser && 914 vm_map_max(map) == sv->sv_maxuser) { 915 shmexit(vmspace); 916 pmap_remove_pages(vmspace_pmap(vmspace)); 917 vm_map_remove(map, vm_map_min(map), vm_map_max(map)); 918 } else { 919 error = vmspace_exec(p, sv->sv_minuser, sv->sv_maxuser); 920 if (error) 921 return (error); 922 vmspace = p->p_vmspace; 923 map = &vmspace->vm_map; 924 } 925 926 /* Allocate a new stack */ 927 if (sv->sv_maxssiz != NULL) 928 ssiz = *sv->sv_maxssiz; 929 else 930 ssiz = maxssiz; 931 stack_addr = sv->sv_usrstack - ssiz; 932 error = vm_map_stack(map, stack_addr, (vm_size_t)ssiz, 933 sv->sv_stackprot, VM_PROT_ALL, MAP_STACK_GROWS_DOWN); 934 if (error) 935 return (error); 936 937 #ifdef __ia64__ 938 /* Allocate a new register stack */ 939 stack_addr = IA64_BACKINGSTORE; 940 error = vm_map_stack(map, stack_addr, (vm_size_t)ssiz, 941 sv->sv_stackprot, VM_PROT_ALL, MAP_STACK_GROWS_UP); 942 if (error) 943 return (error); 944 #endif 945 946 /* vm_ssize and vm_maxsaddr are somewhat antiquated concepts in the 947 * VM_STACK case, but they are still used to monitor the size of the 948 * process stack so we can check the stack rlimit. 949 */ 950 vmspace->vm_ssize = sgrowsiz >> PAGE_SHIFT; 951 vmspace->vm_maxsaddr = (char *)sv->sv_usrstack - ssiz; 952 953 return (0); 954 } 955 956 /* 957 * Copy out argument and environment strings from the old process address 958 * space into the temporary string buffer. 959 */ 960 int 961 exec_copyin_args(struct image_args *args, char *fname, 962 enum uio_seg segflg, char **argv, char **envv) 963 { 964 char *argp, *envp; 965 int error; 966 size_t length; 967 968 error = 0; 969 970 bzero(args, sizeof(*args)); 971 if (argv == NULL) 972 return (EFAULT); 973 /* 974 * Allocate temporary demand zeroed space for argument and 975 * environment strings: 976 * 977 * o ARG_MAX for argument and environment; 978 * o MAXSHELLCMDLEN for the name of interpreters. 979 */ 980 args->buf = (char *) kmem_alloc_wait(exec_map, 981 PATH_MAX + ARG_MAX + MAXSHELLCMDLEN); 982 if (args->buf == NULL) 983 return (ENOMEM); 984 args->begin_argv = args->buf; 985 args->endp = args->begin_argv; 986 args->stringspace = ARG_MAX; 987 988 args->fname = args->buf + ARG_MAX; 989 990 /* 991 * Copy the file name. 992 */ 993 error = (segflg == UIO_SYSSPACE) ? 994 copystr(fname, args->fname, PATH_MAX, &length) : 995 copyinstr(fname, args->fname, PATH_MAX, &length); 996 if (error != 0) 997 goto err_exit; 998 999 /* 1000 * extract arguments first 1001 */ 1002 while ((argp = (caddr_t) (intptr_t) fuword(argv++))) { 1003 if (argp == (caddr_t) -1) { 1004 error = EFAULT; 1005 goto err_exit; 1006 } 1007 if ((error = copyinstr(argp, args->endp, 1008 args->stringspace, &length))) { 1009 if (error == ENAMETOOLONG) 1010 error = E2BIG; 1011 goto err_exit; 1012 } 1013 args->stringspace -= length; 1014 args->endp += length; 1015 args->argc++; 1016 } 1017 1018 args->begin_envv = args->endp; 1019 1020 /* 1021 * extract environment strings 1022 */ 1023 if (envv) { 1024 while ((envp = (caddr_t)(intptr_t)fuword(envv++))) { 1025 if (envp == (caddr_t)-1) { 1026 error = EFAULT; 1027 goto err_exit; 1028 } 1029 if ((error = copyinstr(envp, args->endp, 1030 args->stringspace, &length))) { 1031 if (error == ENAMETOOLONG) 1032 error = E2BIG; 1033 goto err_exit; 1034 } 1035 args->stringspace -= length; 1036 args->endp += length; 1037 args->envc++; 1038 } 1039 } 1040 1041 return (0); 1042 1043 err_exit: 1044 exec_free_args(args); 1045 return (error); 1046 } 1047 1048 static void 1049 exec_free_args(struct image_args *args) 1050 { 1051 1052 if (args->buf) { 1053 kmem_free_wakeup(exec_map, (vm_offset_t)args->buf, 1054 PATH_MAX + ARG_MAX + MAXSHELLCMDLEN); 1055 args->buf = NULL; 1056 } 1057 } 1058 1059 /* 1060 * Copy strings out to the new process address space, constructing new arg 1061 * and env vector tables. Return a pointer to the base so that it can be used 1062 * as the initial stack pointer. 1063 */ 1064 register_t * 1065 exec_copyout_strings(imgp) 1066 struct image_params *imgp; 1067 { 1068 int argc, envc; 1069 char **vectp; 1070 char *stringp, *destp; 1071 register_t *stack_base; 1072 struct ps_strings *arginfo; 1073 struct proc *p; 1074 int szsigcode; 1075 1076 /* 1077 * Calculate string base and vector table pointers. 1078 * Also deal with signal trampoline code for this exec type. 1079 */ 1080 p = imgp->proc; 1081 szsigcode = 0; 1082 arginfo = (struct ps_strings *)p->p_sysent->sv_psstrings; 1083 if (p->p_sysent->sv_szsigcode != NULL) 1084 szsigcode = *(p->p_sysent->sv_szsigcode); 1085 destp = (caddr_t)arginfo - szsigcode - SPARE_USRSPACE - 1086 roundup((ARG_MAX - imgp->args->stringspace), sizeof(char *)); 1087 1088 /* 1089 * install sigcode 1090 */ 1091 if (szsigcode) 1092 copyout(p->p_sysent->sv_sigcode, ((caddr_t)arginfo - 1093 szsigcode), szsigcode); 1094 1095 /* 1096 * If we have a valid auxargs ptr, prepare some room 1097 * on the stack. 1098 */ 1099 if (imgp->auxargs) { 1100 /* 1101 * 'AT_COUNT*2' is size for the ELF Auxargs data. This is for 1102 * lower compatibility. 1103 */ 1104 imgp->auxarg_size = (imgp->auxarg_size) ? imgp->auxarg_size : 1105 (AT_COUNT * 2); 1106 /* 1107 * The '+ 2' is for the null pointers at the end of each of 1108 * the arg and env vector sets,and imgp->auxarg_size is room 1109 * for argument of Runtime loader. 1110 */ 1111 vectp = (char **)(destp - (imgp->args->argc + 1112 imgp->args->envc + 2 + imgp->auxarg_size) * 1113 sizeof(char *)); 1114 1115 } else { 1116 /* 1117 * The '+ 2' is for the null pointers at the end of each of 1118 * the arg and env vector sets 1119 */ 1120 vectp = (char **)(destp - (imgp->args->argc + imgp->args->envc + 2) * 1121 sizeof(char *)); 1122 } 1123 1124 /* 1125 * vectp also becomes our initial stack base 1126 */ 1127 stack_base = (register_t *)vectp; 1128 1129 stringp = imgp->args->begin_argv; 1130 argc = imgp->args->argc; 1131 envc = imgp->args->envc; 1132 1133 /* 1134 * Copy out strings - arguments and environment. 1135 */ 1136 copyout(stringp, destp, ARG_MAX - imgp->args->stringspace); 1137 1138 /* 1139 * Fill in "ps_strings" struct for ps, w, etc. 1140 */ 1141 suword(&arginfo->ps_argvstr, (long)(intptr_t)vectp); 1142 suword(&arginfo->ps_nargvstr, argc); 1143 1144 /* 1145 * Fill in argument portion of vector table. 1146 */ 1147 for (; argc > 0; --argc) { 1148 suword(vectp++, (long)(intptr_t)destp); 1149 while (*stringp++ != 0) 1150 destp++; 1151 destp++; 1152 } 1153 1154 /* a null vector table pointer separates the argp's from the envp's */ 1155 suword(vectp++, 0); 1156 1157 suword(&arginfo->ps_envstr, (long)(intptr_t)vectp); 1158 suword(&arginfo->ps_nenvstr, envc); 1159 1160 /* 1161 * Fill in environment portion of vector table. 1162 */ 1163 for (; envc > 0; --envc) { 1164 suword(vectp++, (long)(intptr_t)destp); 1165 while (*stringp++ != 0) 1166 destp++; 1167 destp++; 1168 } 1169 1170 /* end of vector table is a null pointer */ 1171 suword(vectp, 0); 1172 1173 return (stack_base); 1174 } 1175 1176 /* 1177 * Check permissions of file to execute. 1178 * Called with imgp->vp locked. 1179 * Return 0 for success or error code on failure. 1180 */ 1181 int 1182 exec_check_permissions(imgp) 1183 struct image_params *imgp; 1184 { 1185 struct vnode *vp = imgp->vp; 1186 struct vattr *attr = imgp->attr; 1187 struct thread *td; 1188 int error; 1189 1190 td = curthread; /* XXXKSE */ 1191 1192 /* Get file attributes */ 1193 error = VOP_GETATTR(vp, attr, td->td_ucred, td); 1194 if (error) 1195 return (error); 1196 1197 #ifdef MAC 1198 error = mac_vnode_check_exec(td->td_ucred, imgp->vp, imgp); 1199 if (error) 1200 return (error); 1201 #endif 1202 1203 /* 1204 * 1) Check if file execution is disabled for the filesystem that this 1205 * file resides on. 1206 * 2) Insure that at least one execute bit is on - otherwise root 1207 * will always succeed, and we don't want to happen unless the 1208 * file really is executable. 1209 * 3) Insure that the file is a regular file. 1210 */ 1211 if ((vp->v_mount->mnt_flag & MNT_NOEXEC) || 1212 ((attr->va_mode & 0111) == 0) || 1213 (attr->va_type != VREG)) 1214 return (EACCES); 1215 1216 /* 1217 * Zero length files can't be exec'd 1218 */ 1219 if (attr->va_size == 0) 1220 return (ENOEXEC); 1221 1222 /* 1223 * Check for execute permission to file based on current credentials. 1224 */ 1225 error = VOP_ACCESS(vp, VEXEC, td->td_ucred, td); 1226 if (error) 1227 return (error); 1228 1229 /* 1230 * Check number of open-for-writes on the file and deny execution 1231 * if there are any. 1232 */ 1233 if (vp->v_writecount) 1234 return (ETXTBSY); 1235 1236 /* 1237 * Call filesystem specific open routine (which does nothing in the 1238 * general case). 1239 */ 1240 error = VOP_OPEN(vp, FREAD, td->td_ucred, td, NULL); 1241 return (error); 1242 } 1243 1244 /* 1245 * Exec handler registration 1246 */ 1247 int 1248 exec_register(execsw_arg) 1249 const struct execsw *execsw_arg; 1250 { 1251 const struct execsw **es, **xs, **newexecsw; 1252 int count = 2; /* New slot and trailing NULL */ 1253 1254 if (execsw) 1255 for (es = execsw; *es; es++) 1256 count++; 1257 newexecsw = malloc(count * sizeof(*es), M_TEMP, M_WAITOK); 1258 if (newexecsw == NULL) 1259 return (ENOMEM); 1260 xs = newexecsw; 1261 if (execsw) 1262 for (es = execsw; *es; es++) 1263 *xs++ = *es; 1264 *xs++ = execsw_arg; 1265 *xs = NULL; 1266 if (execsw) 1267 free(execsw, M_TEMP); 1268 execsw = newexecsw; 1269 return (0); 1270 } 1271 1272 int 1273 exec_unregister(execsw_arg) 1274 const struct execsw *execsw_arg; 1275 { 1276 const struct execsw **es, **xs, **newexecsw; 1277 int count = 1; 1278 1279 if (execsw == NULL) 1280 panic("unregister with no handlers left?\n"); 1281 1282 for (es = execsw; *es; es++) { 1283 if (*es == execsw_arg) 1284 break; 1285 } 1286 if (*es == NULL) 1287 return (ENOENT); 1288 for (es = execsw; *es; es++) 1289 if (*es != execsw_arg) 1290 count++; 1291 newexecsw = malloc(count * sizeof(*es), M_TEMP, M_WAITOK); 1292 if (newexecsw == NULL) 1293 return (ENOMEM); 1294 xs = newexecsw; 1295 for (es = execsw; *es; es++) 1296 if (*es != execsw_arg) 1297 *xs++ = *es; 1298 *xs = NULL; 1299 if (execsw) 1300 free(execsw, M_TEMP); 1301 execsw = newexecsw; 1302 return (0); 1303 } 1304