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/sysent.h> 55 #include <sys/shm.h> 56 #include <sys/sysctl.h> 57 #include <sys/user.h> 58 #include <sys/vnode.h> 59 #ifdef KTRACE 60 #include <sys/ktrace.h> 61 #endif 62 63 #include <vm/vm.h> 64 #include <vm/vm_param.h> 65 #include <vm/pmap.h> 66 #include <vm/vm_page.h> 67 #include <vm/vm_map.h> 68 #include <vm/vm_kern.h> 69 #include <vm/vm_extern.h> 70 #include <vm/vm_object.h> 71 #include <vm/vm_pager.h> 72 73 #include <machine/reg.h> 74 75 MALLOC_DEFINE(M_PARGS, "proc-args", "Process arguments"); 76 77 static int sysctl_kern_ps_strings(SYSCTL_HANDLER_ARGS); 78 static int sysctl_kern_usrstack(SYSCTL_HANDLER_ARGS); 79 static int sysctl_kern_stackprot(SYSCTL_HANDLER_ARGS); 80 static int kern_execve(struct thread *td, char *fname, char **argv, 81 char **envv, struct mac *mac_p); 82 83 /* XXX This should be vm_size_t. */ 84 SYSCTL_PROC(_kern, KERN_PS_STRINGS, ps_strings, CTLTYPE_ULONG|CTLFLAG_RD, 85 NULL, 0, sysctl_kern_ps_strings, "LU", ""); 86 87 /* XXX This should be vm_size_t. */ 88 SYSCTL_PROC(_kern, KERN_USRSTACK, usrstack, CTLTYPE_ULONG|CTLFLAG_RD, 89 NULL, 0, sysctl_kern_usrstack, "LU", ""); 90 91 SYSCTL_PROC(_kern, OID_AUTO, stackprot, CTLTYPE_INT|CTLFLAG_RD, 92 NULL, 0, sysctl_kern_stackprot, "I", ""); 93 94 u_long ps_arg_cache_limit = PAGE_SIZE / 16; 95 SYSCTL_ULONG(_kern, OID_AUTO, ps_arg_cache_limit, CTLFLAG_RW, 96 &ps_arg_cache_limit, 0, ""); 97 98 static int 99 sysctl_kern_ps_strings(SYSCTL_HANDLER_ARGS) 100 { 101 struct proc *p; 102 int error; 103 104 p = curproc; 105 #if defined(__amd64__) || defined(__ia64__) 106 if (req->oldlen == sizeof(unsigned int)) { 107 unsigned int val; 108 val = (unsigned int)p->p_sysent->sv_psstrings; 109 error = SYSCTL_OUT(req, &val, sizeof(val)); 110 } else 111 #endif 112 error = SYSCTL_OUT(req, &p->p_sysent->sv_psstrings, 113 sizeof(p->p_sysent->sv_psstrings)); 114 return error; 115 } 116 117 static int 118 sysctl_kern_usrstack(SYSCTL_HANDLER_ARGS) 119 { 120 struct proc *p; 121 int error; 122 123 p = curproc; 124 #if defined(__amd64__) || defined(__ia64__) 125 if (req->oldlen == sizeof(unsigned int)) { 126 unsigned int val; 127 val = (unsigned int)p->p_sysent->sv_usrstack; 128 error = SYSCTL_OUT(req, &val, sizeof(val)); 129 } else 130 #endif 131 error = SYSCTL_OUT(req, &p->p_sysent->sv_usrstack, 132 sizeof(p->p_sysent->sv_usrstack)); 133 return error; 134 } 135 136 static int 137 sysctl_kern_stackprot(SYSCTL_HANDLER_ARGS) 138 { 139 struct proc *p; 140 141 p = curproc; 142 return (SYSCTL_OUT(req, &p->p_sysent->sv_stackprot, 143 sizeof(p->p_sysent->sv_stackprot))); 144 } 145 146 /* 147 * Each of the items is a pointer to a `const struct execsw', hence the 148 * double pointer here. 149 */ 150 static const struct execsw **execsw; 151 152 #ifndef _SYS_SYSPROTO_H_ 153 struct execve_args { 154 char *fname; 155 char **argv; 156 char **envv; 157 }; 158 #endif 159 160 /* 161 * MPSAFE 162 */ 163 int 164 execve(td, uap) 165 struct thread *td; 166 struct execve_args /* { 167 char *fname; 168 char **argv; 169 char **envv; 170 } */ *uap; 171 { 172 173 return (kern_execve(td, uap->fname, uap->argv, uap->envv, NULL)); 174 } 175 176 #ifndef _SYS_SYSPROTO_H_ 177 struct __mac_execve_args { 178 char *fname; 179 char **argv; 180 char **envv; 181 struct mac *mac_p; 182 }; 183 #endif 184 185 /* 186 * MPSAFE 187 */ 188 int 189 __mac_execve(td, uap) 190 struct thread *td; 191 struct __mac_execve_args /* { 192 char *fname; 193 char **argv; 194 char **envv; 195 struct mac *mac_p; 196 } */ *uap; 197 { 198 199 #ifdef MAC 200 return (kern_execve(td, uap->fname, uap->argv, uap->envv, 201 uap->mac_p)); 202 #else 203 return (ENOSYS); 204 #endif 205 } 206 207 /* 208 * In-kernel implementation of execve(). All arguments are assumed to be 209 * userspace pointers from the passed thread. 210 * 211 * MPSAFE 212 */ 213 static int 214 kern_execve(td, fname, argv, envv, mac_p) 215 struct thread *td; 216 char *fname; 217 char **argv; 218 char **envv; 219 struct mac *mac_p; 220 { 221 struct proc *p = td->td_proc; 222 struct nameidata nd, *ndp; 223 struct ucred *newcred = NULL, *oldcred; 224 struct uidinfo *euip; 225 register_t *stack_base; 226 int error, len, i; 227 struct image_params image_params, *imgp; 228 struct vattr attr; 229 int (*img_first)(struct image_params *); 230 struct pargs *oldargs = NULL, *newargs = NULL; 231 struct sigacts *oldsigacts, *newsigacts; 232 #ifdef KTRACE 233 struct vnode *tracevp = NULL; 234 struct ucred *tracecred = NULL; 235 #endif 236 struct vnode *textvp = NULL; 237 int credential_changing; 238 int textset; 239 #ifdef MAC 240 struct label *interplabel = NULL; 241 int will_transition; 242 #endif 243 244 imgp = &image_params; 245 246 /* 247 * Lock the process and set the P_INEXEC flag to indicate that 248 * it should be left alone until we're done here. This is 249 * necessary to avoid race conditions - e.g. in ptrace() - 250 * that might allow a local user to illicitly obtain elevated 251 * privileges. 252 */ 253 PROC_LOCK(p); 254 KASSERT((p->p_flag & P_INEXEC) == 0, 255 ("%s(): process already has P_INEXEC flag", __func__)); 256 if (p->p_flag & P_SA || p->p_numthreads > 1) { 257 if (thread_single(SINGLE_EXIT)) { 258 PROC_UNLOCK(p); 259 mtx_unlock(&Giant); 260 return (ERESTART); /* Try again later. */ 261 } 262 /* 263 * If we get here all other threads are dead, 264 * so unset the associated flags and lose KSE mode. 265 */ 266 p->p_flag &= ~P_SA; 267 td->td_mailbox = NULL; 268 thread_single_end(); 269 } 270 p->p_flag |= P_INEXEC; 271 PROC_UNLOCK(p); 272 273 /* 274 * Initialize part of the common data 275 */ 276 imgp->proc = p; 277 imgp->userspace_argv = argv; 278 imgp->userspace_envv = envv; 279 imgp->execlabel = NULL; 280 imgp->attr = &attr; 281 imgp->argc = imgp->envc = 0; 282 imgp->argv0 = NULL; 283 imgp->entry_addr = 0; 284 imgp->vmspace_destroyed = 0; 285 imgp->interpreted = 0; 286 imgp->interpreter_name[0] = '\0'; 287 imgp->auxargs = NULL; 288 imgp->vp = NULL; 289 imgp->object = NULL; 290 imgp->firstpage = NULL; 291 imgp->ps_strings = 0; 292 imgp->auxarg_size = 0; 293 294 #ifdef MAC 295 error = mac_execve_enter(imgp, mac_p); 296 if (error) { 297 mtx_lock(&Giant); 298 goto exec_fail; 299 } 300 #endif 301 302 /* 303 * Allocate temporary demand zeroed space for argument and 304 * environment strings 305 */ 306 imgp->stringbase = (char *)kmem_alloc_wait(exec_map, ARG_MAX + 307 PAGE_SIZE); 308 if (imgp->stringbase == NULL) { 309 error = ENOMEM; 310 mtx_lock(&Giant); 311 goto exec_fail; 312 } 313 imgp->stringp = imgp->stringbase; 314 imgp->stringspace = ARG_MAX; 315 imgp->image_header = imgp->stringbase + ARG_MAX; 316 317 /* 318 * Translate the file name. namei() returns a vnode pointer 319 * in ni_vp amoung other things. 320 */ 321 ndp = &nd; 322 NDINIT(ndp, LOOKUP, LOCKLEAF | FOLLOW | SAVENAME, 323 UIO_USERSPACE, fname, td); 324 325 mtx_lock(&Giant); 326 interpret: 327 328 error = namei(ndp); 329 if (error) { 330 kmem_free_wakeup(exec_map, (vm_offset_t)imgp->stringbase, 331 ARG_MAX + PAGE_SIZE); 332 goto exec_fail; 333 } 334 335 imgp->vp = ndp->ni_vp; 336 imgp->fname = fname; 337 338 /* 339 * Check file permissions (also 'opens' file) 340 */ 341 error = exec_check_permissions(imgp); 342 if (error) 343 goto exec_fail_dealloc; 344 345 if (VOP_GETVOBJECT(imgp->vp, &imgp->object) == 0) 346 vm_object_reference(imgp->object); 347 348 /* 349 * Set VV_TEXT now so no one can write to the executable while we're 350 * activating it. 351 * 352 * Remember if this was set before and unset it in case this is not 353 * actually an executable image. 354 */ 355 textset = imgp->vp->v_vflag & VV_TEXT; 356 imgp->vp->v_vflag |= VV_TEXT; 357 358 error = exec_map_first_page(imgp); 359 if (error) 360 goto exec_fail_dealloc; 361 362 /* 363 * If the current process has a special image activator it 364 * wants to try first, call it. For example, emulating shell 365 * scripts differently. 366 */ 367 error = -1; 368 if ((img_first = imgp->proc->p_sysent->sv_imgact_try) != NULL) 369 error = img_first(imgp); 370 371 /* 372 * Loop through the list of image activators, calling each one. 373 * An activator returns -1 if there is no match, 0 on success, 374 * and an error otherwise. 375 */ 376 for (i = 0; error == -1 && execsw[i]; ++i) { 377 if (execsw[i]->ex_imgact == NULL || 378 execsw[i]->ex_imgact == img_first) { 379 continue; 380 } 381 error = (*execsw[i]->ex_imgact)(imgp); 382 } 383 384 if (error) { 385 if (error == -1) { 386 if (textset == 0) 387 imgp->vp->v_vflag &= ~VV_TEXT; 388 error = ENOEXEC; 389 } 390 goto exec_fail_dealloc; 391 } 392 393 /* 394 * Special interpreter operation, cleanup and loop up to try to 395 * activate the interpreter. 396 */ 397 if (imgp->interpreted) { 398 exec_unmap_first_page(imgp); 399 /* 400 * VV_TEXT needs to be unset for scripts. There is a short 401 * period before we determine that something is a script where 402 * VV_TEXT will be set. The vnode lock is held over this 403 * entire period so nothing should illegitimately be blocked. 404 */ 405 imgp->vp->v_vflag &= ~VV_TEXT; 406 /* free name buffer and old vnode */ 407 NDFREE(ndp, NDF_ONLY_PNBUF); 408 #ifdef MAC 409 interplabel = mac_vnode_label_alloc(); 410 mac_copy_vnode_label(ndp->ni_vp->v_label, interplabel); 411 #endif 412 vput(ndp->ni_vp); 413 vm_object_deallocate(imgp->object); 414 imgp->object = NULL; 415 /* set new name to that of the interpreter */ 416 NDINIT(ndp, LOOKUP, LOCKLEAF | FOLLOW | SAVENAME, 417 UIO_SYSSPACE, imgp->interpreter_name, td); 418 goto interpret; 419 } 420 421 /* 422 * Copy out strings (args and env) and initialize stack base 423 */ 424 if (p->p_sysent->sv_copyout_strings) 425 stack_base = (*p->p_sysent->sv_copyout_strings)(imgp); 426 else 427 stack_base = exec_copyout_strings(imgp); 428 429 /* 430 * If custom stack fixup routine present for this process 431 * let it do the stack setup. 432 * Else stuff argument count as first item on stack 433 */ 434 if (p->p_sysent->sv_fixup != NULL) 435 (*p->p_sysent->sv_fixup)(&stack_base, imgp); 436 else 437 suword(--stack_base, imgp->argc); 438 439 /* 440 * For security and other reasons, the file descriptor table cannot 441 * be shared after an exec. 442 */ 443 FILEDESC_LOCK(p->p_fd); 444 if (p->p_fd->fd_refcnt > 1) { 445 struct filedesc *tmp; 446 447 tmp = fdcopy(td->td_proc->p_fd); 448 FILEDESC_UNLOCK(p->p_fd); 449 fdfree(td); 450 p->p_fd = tmp; 451 } else 452 FILEDESC_UNLOCK(p->p_fd); 453 454 /* 455 * Malloc things before we need locks. 456 */ 457 newcred = crget(); 458 euip = uifind(attr.va_uid); 459 i = imgp->endargs - imgp->stringbase; 460 if (ps_arg_cache_limit >= i + sizeof(struct pargs)) 461 newargs = pargs_alloc(i); 462 463 /* close files on exec */ 464 fdcloseexec(td); 465 466 /* Get a reference to the vnode prior to locking the proc */ 467 VREF(ndp->ni_vp); 468 469 /* 470 * For security and other reasons, signal handlers cannot 471 * be shared after an exec. The new process gets a copy of the old 472 * handlers. In execsigs(), the new process will have its signals 473 * reset. 474 */ 475 PROC_LOCK(p); 476 if (sigacts_shared(p->p_sigacts)) { 477 oldsigacts = p->p_sigacts; 478 PROC_UNLOCK(p); 479 newsigacts = sigacts_alloc(); 480 sigacts_copy(newsigacts, oldsigacts); 481 PROC_LOCK(p); 482 p->p_sigacts = newsigacts; 483 } else 484 oldsigacts = NULL; 485 486 /* Stop profiling */ 487 stopprofclock(p); 488 489 /* reset caught signals */ 490 execsigs(p); 491 492 /* name this process - nameiexec(p, ndp) */ 493 len = min(ndp->ni_cnd.cn_namelen,MAXCOMLEN); 494 bcopy(ndp->ni_cnd.cn_nameptr, p->p_comm, len); 495 p->p_comm[len] = 0; 496 497 /* 498 * mark as execed, wakeup the process that vforked (if any) and tell 499 * it that it now has its own resources back 500 */ 501 p->p_flag |= P_EXEC; 502 if (p->p_pptr && (p->p_flag & P_PPWAIT)) { 503 p->p_flag &= ~P_PPWAIT; 504 wakeup(p->p_pptr); 505 } 506 507 /* 508 * Implement image setuid/setgid. 509 * 510 * Don't honor setuid/setgid if the filesystem prohibits it or if 511 * the process is being traced. 512 * 513 * XXXMAC: For the time being, use NOSUID to also prohibit 514 * transitions on the file system. 515 */ 516 oldcred = p->p_ucred; 517 credential_changing = 0; 518 credential_changing |= (attr.va_mode & VSUID) && oldcred->cr_uid != 519 attr.va_uid; 520 credential_changing |= (attr.va_mode & VSGID) && oldcred->cr_gid != 521 attr.va_gid; 522 #ifdef MAC 523 will_transition = mac_execve_will_transition(oldcred, imgp->vp, 524 interplabel, imgp); 525 credential_changing |= will_transition; 526 #endif 527 528 if (credential_changing && 529 (imgp->vp->v_mount->mnt_flag & MNT_NOSUID) == 0 && 530 (p->p_flag & P_TRACED) == 0) { 531 /* 532 * Turn off syscall tracing for set-id programs, except for 533 * root. Record any set-id flags first to make sure that 534 * we do not regain any tracing during a possible block. 535 */ 536 setsugid(p); 537 #ifdef KTRACE 538 if (p->p_tracevp != NULL && suser_cred(oldcred, PRISON_ROOT)) { 539 mtx_lock(&ktrace_mtx); 540 p->p_traceflag = 0; 541 tracevp = p->p_tracevp; 542 p->p_tracevp = NULL; 543 tracecred = p->p_tracecred; 544 p->p_tracecred = NULL; 545 mtx_unlock(&ktrace_mtx); 546 } 547 #endif 548 /* 549 * Close any file descriptors 0..2 that reference procfs, 550 * then make sure file descriptors 0..2 are in use. 551 * 552 * setugidsafety() may call closef() and then pfind() 553 * which may grab the process lock. 554 * fdcheckstd() may call falloc() which may block to 555 * allocate memory, so temporarily drop the process lock. 556 */ 557 PROC_UNLOCK(p); 558 setugidsafety(td); 559 error = fdcheckstd(td); 560 if (error != 0) 561 goto done1; 562 PROC_LOCK(p); 563 /* 564 * Set the new credentials. 565 */ 566 crcopy(newcred, oldcred); 567 if (attr.va_mode & VSUID) 568 change_euid(newcred, euip); 569 if (attr.va_mode & VSGID) 570 change_egid(newcred, attr.va_gid); 571 #ifdef MAC 572 if (will_transition) { 573 mac_execve_transition(oldcred, newcred, imgp->vp, 574 interplabel, imgp); 575 } 576 #endif 577 /* 578 * Implement correct POSIX saved-id behavior. 579 * 580 * XXXMAC: Note that the current logic will save the 581 * uid and gid if a MAC domain transition occurs, even 582 * though maybe it shouldn't. 583 */ 584 change_svuid(newcred, newcred->cr_uid); 585 change_svgid(newcred, newcred->cr_gid); 586 p->p_ucred = newcred; 587 newcred = NULL; 588 } else { 589 if (oldcred->cr_uid == oldcred->cr_ruid && 590 oldcred->cr_gid == oldcred->cr_rgid) 591 p->p_flag &= ~P_SUGID; 592 /* 593 * Implement correct POSIX saved-id behavior. 594 * 595 * XXX: It's not clear that the existing behavior is 596 * POSIX-compliant. A number of sources indicate that the 597 * saved uid/gid should only be updated if the new ruid is 598 * not equal to the old ruid, or the new euid is not equal 599 * to the old euid and the new euid is not equal to the old 600 * ruid. The FreeBSD code always updates the saved uid/gid. 601 * Also, this code uses the new (replaced) euid and egid as 602 * the source, which may or may not be the right ones to use. 603 */ 604 if (oldcred->cr_svuid != oldcred->cr_uid || 605 oldcred->cr_svgid != oldcred->cr_gid) { 606 crcopy(newcred, oldcred); 607 change_svuid(newcred, newcred->cr_uid); 608 change_svgid(newcred, newcred->cr_gid); 609 p->p_ucred = newcred; 610 newcred = NULL; 611 } 612 } 613 614 /* 615 * Store the vp for use in procfs. This vnode was referenced prior 616 * to locking the proc lock. 617 */ 618 textvp = p->p_textvp; 619 p->p_textvp = ndp->ni_vp; 620 621 /* 622 * Notify others that we exec'd, and clear the P_INEXEC flag 623 * as we're now a bona fide freshly-execed process. 624 */ 625 KNOTE(&p->p_klist, NOTE_EXEC); 626 p->p_flag &= ~P_INEXEC; 627 628 /* 629 * If tracing the process, trap to debugger so breakpoints 630 * can be set before the program executes. 631 */ 632 if (p->p_flag & P_TRACED) 633 psignal(p, SIGTRAP); 634 635 /* clear "fork but no exec" flag, as we _are_ execing */ 636 p->p_acflag &= ~AFORK; 637 638 /* Free any previous argument cache */ 639 oldargs = p->p_args; 640 p->p_args = NULL; 641 642 /* Cache arguments if they fit inside our allowance */ 643 if (ps_arg_cache_limit >= i + sizeof(struct pargs)) { 644 bcopy(imgp->stringbase, newargs->ar_args, i); 645 p->p_args = newargs; 646 newargs = NULL; 647 } 648 PROC_UNLOCK(p); 649 650 /* Set values passed into the program in registers. */ 651 if (p->p_sysent->sv_setregs) 652 (*p->p_sysent->sv_setregs)(td, imgp->entry_addr, 653 (u_long)(uintptr_t)stack_base, imgp->ps_strings); 654 else 655 exec_setregs(td, imgp->entry_addr, 656 (u_long)(uintptr_t)stack_base, imgp->ps_strings); 657 658 done1: 659 /* 660 * Free any resources malloc'd earlier that we didn't use. 661 */ 662 uifree(euip); 663 if (newcred == NULL) 664 crfree(oldcred); 665 else 666 crfree(newcred); 667 /* 668 * Handle deferred decrement of ref counts. 669 */ 670 if (textvp != NULL) 671 vrele(textvp); 672 if (ndp->ni_vp && error != 0) 673 vrele(ndp->ni_vp); 674 #ifdef KTRACE 675 if (tracevp != NULL) 676 vrele(tracevp); 677 if (tracecred != NULL) 678 crfree(tracecred); 679 #endif 680 if (oldargs != NULL) 681 pargs_drop(oldargs); 682 if (newargs != NULL) 683 pargs_drop(newargs); 684 if (oldsigacts != NULL) 685 sigacts_free(oldsigacts); 686 687 exec_fail_dealloc: 688 689 /* 690 * free various allocated resources 691 */ 692 if (imgp->firstpage != NULL) 693 exec_unmap_first_page(imgp); 694 695 if (imgp->vp != NULL) { 696 NDFREE(ndp, NDF_ONLY_PNBUF); 697 vput(imgp->vp); 698 } 699 700 if (imgp->stringbase != NULL) 701 kmem_free_wakeup(exec_map, (vm_offset_t)imgp->stringbase, 702 ARG_MAX + PAGE_SIZE); 703 704 if (imgp->object != NULL) 705 vm_object_deallocate(imgp->object); 706 707 if (error == 0) { 708 /* 709 * Stop the process here if its stop event mask has 710 * the S_EXEC bit set. 711 */ 712 STOPEVENT(p, S_EXEC, 0); 713 goto done2; 714 } 715 716 exec_fail: 717 /* we're done here, clear P_INEXEC */ 718 PROC_LOCK(p); 719 p->p_flag &= ~P_INEXEC; 720 PROC_UNLOCK(p); 721 722 if (imgp->vmspace_destroyed) { 723 /* sorry, no more process anymore. exit gracefully */ 724 #ifdef MAC 725 mac_execve_exit(imgp); 726 if (interplabel != NULL) 727 mac_vnode_label_free(interplabel); 728 #endif 729 exit1(td, W_EXITCODE(0, SIGABRT)); 730 /* NOT REACHED */ 731 error = 0; 732 } 733 done2: 734 #ifdef MAC 735 mac_execve_exit(imgp); 736 if (interplabel != NULL) 737 mac_vnode_label_free(interplabel); 738 #endif 739 mtx_unlock(&Giant); 740 return (error); 741 } 742 743 int 744 exec_map_first_page(imgp) 745 struct image_params *imgp; 746 { 747 int rv, i; 748 int initial_pagein; 749 vm_page_t ma[VM_INITIAL_PAGEIN]; 750 vm_object_t object; 751 752 GIANT_REQUIRED; 753 754 if (imgp->firstpage != NULL) 755 exec_unmap_first_page(imgp); 756 757 VOP_GETVOBJECT(imgp->vp, &object); 758 VM_OBJECT_LOCK(object); 759 ma[0] = vm_page_grab(object, 0, VM_ALLOC_NORMAL | VM_ALLOC_RETRY); 760 if ((ma[0]->valid & VM_PAGE_BITS_ALL) != VM_PAGE_BITS_ALL) { 761 initial_pagein = VM_INITIAL_PAGEIN; 762 if (initial_pagein > object->size) 763 initial_pagein = object->size; 764 for (i = 1; i < initial_pagein; i++) { 765 if ((ma[i] = vm_page_lookup(object, i)) != NULL) { 766 if (ma[i]->valid) 767 break; 768 vm_page_lock_queues(); 769 if ((ma[i]->flags & PG_BUSY) || ma[i]->busy) { 770 vm_page_unlock_queues(); 771 break; 772 } 773 vm_page_busy(ma[i]); 774 vm_page_unlock_queues(); 775 } else { 776 ma[i] = vm_page_alloc(object, i, 777 VM_ALLOC_NORMAL); 778 if (ma[i] == NULL) 779 break; 780 } 781 } 782 initial_pagein = i; 783 rv = vm_pager_get_pages(object, ma, initial_pagein, 0); 784 ma[0] = vm_page_lookup(object, 0); 785 if ((rv != VM_PAGER_OK) || (ma[0] == NULL) || 786 (ma[0]->valid == 0)) { 787 if (ma[0]) { 788 vm_page_lock_queues(); 789 pmap_remove_all(ma[0]); 790 vm_page_free(ma[0]); 791 vm_page_unlock_queues(); 792 } 793 VM_OBJECT_UNLOCK(object); 794 return (EIO); 795 } 796 } 797 vm_page_lock_queues(); 798 vm_page_wire(ma[0]); 799 vm_page_wakeup(ma[0]); 800 vm_page_unlock_queues(); 801 VM_OBJECT_UNLOCK(object); 802 803 pmap_qenter((vm_offset_t)imgp->image_header, ma, 1); 804 imgp->firstpage = ma[0]; 805 806 return (0); 807 } 808 809 void 810 exec_unmap_first_page(imgp) 811 struct image_params *imgp; 812 { 813 814 if (imgp->firstpage != NULL) { 815 pmap_qremove((vm_offset_t)imgp->image_header, 1); 816 vm_page_lock_queues(); 817 vm_page_unwire(imgp->firstpage, 1); 818 vm_page_unlock_queues(); 819 imgp->firstpage = NULL; 820 } 821 } 822 823 /* 824 * Destroy old address space, and allocate a new stack 825 * The new stack is only SGROWSIZ large because it is grown 826 * automatically in trap.c. 827 */ 828 int 829 exec_new_vmspace(imgp, sv) 830 struct image_params *imgp; 831 struct sysentvec *sv; 832 { 833 int error; 834 struct proc *p = imgp->proc; 835 struct vmspace *vmspace = p->p_vmspace; 836 vm_offset_t stack_addr; 837 vm_map_t map; 838 839 GIANT_REQUIRED; 840 841 imgp->vmspace_destroyed = 1; 842 843 /* Called with Giant held, do not depend on it! */ 844 EVENTHANDLER_INVOKE(process_exec, p); 845 846 /* 847 * Here is as good a place as any to do any resource limit cleanups. 848 * This is needed if a 64 bit binary exec's a 32 bit binary - the 849 * data size limit may need to be changed to a value that makes 850 * sense for the 32 bit binary. 851 */ 852 if (sv->sv_fixlimits != NULL) 853 sv->sv_fixlimits(imgp); 854 855 /* 856 * Blow away entire process VM, if address space not shared, 857 * otherwise, create a new VM space so that other threads are 858 * not disrupted 859 */ 860 map = &vmspace->vm_map; 861 if (vmspace->vm_refcnt == 1 && vm_map_min(map) == sv->sv_minuser && 862 vm_map_max(map) == sv->sv_maxuser) { 863 shmexit(vmspace); 864 vm_page_lock_queues(); 865 pmap_remove_pages(vmspace_pmap(vmspace), vm_map_min(map), 866 vm_map_max(map)); 867 vm_page_unlock_queues(); 868 vm_map_remove(map, vm_map_min(map), vm_map_max(map)); 869 } else { 870 vmspace_exec(p, sv->sv_minuser, sv->sv_maxuser); 871 vmspace = p->p_vmspace; 872 map = &vmspace->vm_map; 873 } 874 875 /* Allocate a new stack */ 876 stack_addr = sv->sv_usrstack - maxssiz; 877 error = vm_map_stack(map, stack_addr, (vm_size_t)maxssiz, 878 sv->sv_stackprot, VM_PROT_ALL, MAP_STACK_GROWS_DOWN); 879 if (error) 880 return (error); 881 882 #ifdef __ia64__ 883 /* Allocate a new register stack */ 884 stack_addr = IA64_BACKINGSTORE; 885 error = vm_map_stack(map, stack_addr, (vm_size_t)maxssiz, 886 sv->sv_stackprot, VM_PROT_ALL, MAP_STACK_GROWS_UP); 887 if (error) 888 return (error); 889 #endif 890 891 /* vm_ssize and vm_maxsaddr are somewhat antiquated concepts in the 892 * VM_STACK case, but they are still used to monitor the size of the 893 * process stack so we can check the stack rlimit. 894 */ 895 vmspace->vm_ssize = sgrowsiz >> PAGE_SHIFT; 896 vmspace->vm_maxsaddr = (char *)sv->sv_usrstack - maxssiz; 897 898 return (0); 899 } 900 901 /* 902 * Copy out argument and environment strings from the old process 903 * address space into the temporary string buffer. 904 */ 905 int 906 exec_extract_strings(imgp) 907 struct image_params *imgp; 908 { 909 char **argv, **envv; 910 char *argp, *envp; 911 int error; 912 size_t length; 913 914 /* 915 * extract arguments first 916 */ 917 918 argv = imgp->userspace_argv; 919 920 if (argv) { 921 argp = (caddr_t)(intptr_t)fuword(argv); 922 if (argp == (caddr_t)-1) 923 return (EFAULT); 924 if (argp) 925 argv++; 926 if (imgp->argv0) 927 argp = imgp->argv0; 928 if (argp) { 929 do { 930 if (argp == (caddr_t)-1) 931 return (EFAULT); 932 if ((error = copyinstr(argp, imgp->stringp, 933 imgp->stringspace, &length))) { 934 if (error == ENAMETOOLONG) 935 return (E2BIG); 936 return (error); 937 } 938 imgp->stringspace -= length; 939 imgp->stringp += length; 940 imgp->argc++; 941 } while ((argp = (caddr_t)(intptr_t)fuword(argv++))); 942 } 943 } else 944 return (EFAULT); 945 946 imgp->endargs = imgp->stringp; 947 948 /* 949 * extract environment strings 950 */ 951 952 envv = imgp->userspace_envv; 953 954 if (envv) { 955 while ((envp = (caddr_t)(intptr_t)fuword(envv++))) { 956 if (envp == (caddr_t)-1) 957 return (EFAULT); 958 if ((error = copyinstr(envp, imgp->stringp, 959 imgp->stringspace, &length))) { 960 if (error == ENAMETOOLONG) 961 return (E2BIG); 962 return (error); 963 } 964 imgp->stringspace -= length; 965 imgp->stringp += length; 966 imgp->envc++; 967 } 968 } 969 970 return (0); 971 } 972 973 /* 974 * Copy strings out to the new process address space, constructing 975 * new arg and env vector tables. Return a pointer to the base 976 * so that it can be used as the initial stack pointer. 977 */ 978 register_t * 979 exec_copyout_strings(imgp) 980 struct image_params *imgp; 981 { 982 int argc, envc; 983 char **vectp; 984 char *stringp, *destp; 985 register_t *stack_base; 986 struct ps_strings *arginfo; 987 struct proc *p; 988 int szsigcode; 989 990 /* 991 * Calculate string base and vector table pointers. 992 * Also deal with signal trampoline code for this exec type. 993 */ 994 p = imgp->proc; 995 szsigcode = 0; 996 arginfo = (struct ps_strings *)p->p_sysent->sv_psstrings; 997 if (p->p_sysent->sv_szsigcode != NULL) 998 szsigcode = *(p->p_sysent->sv_szsigcode); 999 destp = (caddr_t)arginfo - szsigcode - SPARE_USRSPACE - 1000 roundup((ARG_MAX - imgp->stringspace), sizeof(char *)); 1001 1002 /* 1003 * install sigcode 1004 */ 1005 if (szsigcode) 1006 copyout(p->p_sysent->sv_sigcode, ((caddr_t)arginfo - 1007 szsigcode), szsigcode); 1008 1009 /* 1010 * If we have a valid auxargs ptr, prepare some room 1011 * on the stack. 1012 */ 1013 if (imgp->auxargs) { 1014 /* 1015 * 'AT_COUNT*2' is size for the ELF Auxargs data. This is for 1016 * lower compatibility. 1017 */ 1018 imgp->auxarg_size = (imgp->auxarg_size) ? imgp->auxarg_size : 1019 (AT_COUNT * 2); 1020 /* 1021 * The '+ 2' is for the null pointers at the end of each of 1022 * the arg and env vector sets,and imgp->auxarg_size is room 1023 * for argument of Runtime loader. 1024 */ 1025 vectp = (char **)(destp - (imgp->argc + imgp->envc + 2 + 1026 imgp->auxarg_size) * sizeof(char *)); 1027 1028 } else 1029 /* 1030 * The '+ 2' is for the null pointers at the end of each of 1031 * the arg and env vector sets 1032 */ 1033 vectp = (char **)(destp - (imgp->argc + imgp->envc + 2) * 1034 sizeof(char *)); 1035 1036 /* 1037 * vectp also becomes our initial stack base 1038 */ 1039 stack_base = (register_t *)vectp; 1040 1041 stringp = imgp->stringbase; 1042 argc = imgp->argc; 1043 envc = imgp->envc; 1044 1045 /* 1046 * Copy out strings - arguments and environment. 1047 */ 1048 copyout(stringp, destp, ARG_MAX - imgp->stringspace); 1049 1050 /* 1051 * Fill in "ps_strings" struct for ps, w, etc. 1052 */ 1053 suword(&arginfo->ps_argvstr, (long)(intptr_t)vectp); 1054 suword(&arginfo->ps_nargvstr, argc); 1055 1056 /* 1057 * Fill in argument portion of vector table. 1058 */ 1059 for (; argc > 0; --argc) { 1060 suword(vectp++, (long)(intptr_t)destp); 1061 while (*stringp++ != 0) 1062 destp++; 1063 destp++; 1064 } 1065 1066 /* a null vector table pointer separates the argp's from the envp's */ 1067 suword(vectp++, 0); 1068 1069 suword(&arginfo->ps_envstr, (long)(intptr_t)vectp); 1070 suword(&arginfo->ps_nenvstr, envc); 1071 1072 /* 1073 * Fill in environment portion of vector table. 1074 */ 1075 for (; envc > 0; --envc) { 1076 suword(vectp++, (long)(intptr_t)destp); 1077 while (*stringp++ != 0) 1078 destp++; 1079 destp++; 1080 } 1081 1082 /* end of vector table is a null pointer */ 1083 suword(vectp, 0); 1084 1085 return (stack_base); 1086 } 1087 1088 /* 1089 * Check permissions of file to execute. 1090 * Called with imgp->vp locked. 1091 * Return 0 for success or error code on failure. 1092 */ 1093 int 1094 exec_check_permissions(imgp) 1095 struct image_params *imgp; 1096 { 1097 struct vnode *vp = imgp->vp; 1098 struct vattr *attr = imgp->attr; 1099 struct thread *td; 1100 int error; 1101 1102 td = curthread; /* XXXKSE */ 1103 1104 /* Get file attributes */ 1105 error = VOP_GETATTR(vp, attr, td->td_ucred, td); 1106 if (error) 1107 return (error); 1108 1109 #ifdef MAC 1110 error = mac_check_vnode_exec(td->td_ucred, imgp->vp, imgp); 1111 if (error) 1112 return (error); 1113 #endif 1114 1115 /* 1116 * 1) Check if file execution is disabled for the filesystem that this 1117 * file resides on. 1118 * 2) Insure that at least one execute bit is on - otherwise root 1119 * will always succeed, and we don't want to happen unless the 1120 * file really is executable. 1121 * 3) Insure that the file is a regular file. 1122 */ 1123 if ((vp->v_mount->mnt_flag & MNT_NOEXEC) || 1124 ((attr->va_mode & 0111) == 0) || 1125 (attr->va_type != VREG)) 1126 return (EACCES); 1127 1128 /* 1129 * Zero length files can't be exec'd 1130 */ 1131 if (attr->va_size == 0) 1132 return (ENOEXEC); 1133 1134 /* 1135 * Check for execute permission to file based on current credentials. 1136 */ 1137 error = VOP_ACCESS(vp, VEXEC, td->td_ucred, td); 1138 if (error) 1139 return (error); 1140 1141 /* 1142 * Check number of open-for-writes on the file and deny execution 1143 * if there are any. 1144 */ 1145 if (vp->v_writecount) 1146 return (ETXTBSY); 1147 1148 /* 1149 * Call filesystem specific open routine (which does nothing in the 1150 * general case). 1151 */ 1152 error = VOP_OPEN(vp, FREAD, td->td_ucred, td, -1); 1153 return (error); 1154 } 1155 1156 /* 1157 * Exec handler registration 1158 */ 1159 int 1160 exec_register(execsw_arg) 1161 const struct execsw *execsw_arg; 1162 { 1163 const struct execsw **es, **xs, **newexecsw; 1164 int count = 2; /* New slot and trailing NULL */ 1165 1166 if (execsw) 1167 for (es = execsw; *es; es++) 1168 count++; 1169 newexecsw = malloc(count * sizeof(*es), M_TEMP, M_WAITOK); 1170 if (newexecsw == NULL) 1171 return (ENOMEM); 1172 xs = newexecsw; 1173 if (execsw) 1174 for (es = execsw; *es; es++) 1175 *xs++ = *es; 1176 *xs++ = execsw_arg; 1177 *xs = NULL; 1178 if (execsw) 1179 free(execsw, M_TEMP); 1180 execsw = newexecsw; 1181 return (0); 1182 } 1183 1184 int 1185 exec_unregister(execsw_arg) 1186 const struct execsw *execsw_arg; 1187 { 1188 const struct execsw **es, **xs, **newexecsw; 1189 int count = 1; 1190 1191 if (execsw == NULL) 1192 panic("unregister with no handlers left?\n"); 1193 1194 for (es = execsw; *es; es++) { 1195 if (*es == execsw_arg) 1196 break; 1197 } 1198 if (*es == NULL) 1199 return (ENOENT); 1200 for (es = execsw; *es; es++) 1201 if (*es != execsw_arg) 1202 count++; 1203 newexecsw = malloc(count * sizeof(*es), M_TEMP, M_WAITOK); 1204 if (newexecsw == NULL) 1205 return (ENOMEM); 1206 xs = newexecsw; 1207 for (es = execsw; *es; es++) 1208 if (*es != execsw_arg) 1209 *xs++ = *es; 1210 *xs = NULL; 1211 if (execsw) 1212 free(execsw, M_TEMP); 1213 execsw = newexecsw; 1214 return (0); 1215 } 1216