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