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