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 #ifdef __ia64__ 102 /* XXX HACK */ 103 static int regstkpages = 256; 104 SYSCTL_INT(_machdep, OID_AUTO, regstkpages, CTLFLAG_RW, ®stkpages, 0, ""); 105 #endif 106 107 static int 108 sysctl_kern_ps_strings(SYSCTL_HANDLER_ARGS) 109 { 110 struct proc *p; 111 112 p = curproc; 113 return (SYSCTL_OUT(req, &p->p_sysent->sv_psstrings, 114 sizeof(p->p_sysent->sv_psstrings))); 115 } 116 117 static int 118 sysctl_kern_usrstack(SYSCTL_HANDLER_ARGS) 119 { 120 struct proc *p; 121 122 p = curproc; 123 return (SYSCTL_OUT(req, &p->p_sysent->sv_usrstack, 124 sizeof(p->p_sysent->sv_usrstack))); 125 } 126 127 static int 128 sysctl_kern_stackprot(SYSCTL_HANDLER_ARGS) 129 { 130 struct proc *p; 131 132 p = curproc; 133 return (SYSCTL_OUT(req, &p->p_sysent->sv_stackprot, 134 sizeof(p->p_sysent->sv_stackprot))); 135 } 136 137 /* 138 * Each of the items is a pointer to a `const struct execsw', hence the 139 * double pointer here. 140 */ 141 static const struct execsw **execsw; 142 143 /* 144 * In-kernel implementation of execve(). All arguments are assumed to be 145 * userspace pointers from the passed thread. 146 * 147 * MPSAFE 148 */ 149 static int 150 kern_execve(td, fname, argv, envv, mac_p) 151 struct thread *td; 152 char *fname; 153 char **argv; 154 char **envv; 155 struct mac *mac_p; 156 { 157 struct proc *p = td->td_proc; 158 struct nameidata nd, *ndp; 159 struct ucred *newcred = NULL, *oldcred; 160 struct uidinfo *euip; 161 register_t *stack_base; 162 int error, len, i; 163 struct image_params image_params, *imgp; 164 struct vattr attr; 165 int (*img_first)(struct image_params *); 166 struct pargs *oldargs = NULL, *newargs = NULL; 167 struct sigacts *oldsigacts, *newsigacts; 168 #ifdef KTRACE 169 struct vnode *tracevp = NULL; 170 struct ucred *tracecred = NULL; 171 #endif 172 struct vnode *textvp = NULL; 173 int credential_changing; 174 int textset; 175 #ifdef MAC 176 struct label interplabel; /* label of the interpreted vnode */ 177 struct label execlabel; /* optional label argument */ 178 int will_transition, interplabelvalid = 0; 179 #endif 180 181 imgp = &image_params; 182 183 /* 184 * Lock the process and set the P_INEXEC flag to indicate that 185 * it should be left alone until we're done here. This is 186 * necessary to avoid race conditions - e.g. in ptrace() - 187 * that might allow a local user to illicitly obtain elevated 188 * privileges. 189 */ 190 PROC_LOCK(p); 191 KASSERT((p->p_flag & P_INEXEC) == 0, 192 ("%s(): process already has P_INEXEC flag", __func__)); 193 if (p->p_flag & P_SA || p->p_numthreads > 1) { 194 if (thread_single(SINGLE_EXIT)) { 195 PROC_UNLOCK(p); 196 return (ERESTART); /* Try again later. */ 197 } 198 /* 199 * If we get here all other threads are dead, 200 * so unset the associated flags and lose KSE mode. 201 */ 202 p->p_flag &= ~P_SA; 203 td->td_mailbox = NULL; 204 thread_single_end(); 205 } 206 p->p_flag |= P_INEXEC; 207 PROC_UNLOCK(p); 208 209 /* 210 * Initialize part of the common data 211 */ 212 imgp->proc = p; 213 imgp->userspace_argv = argv; 214 imgp->userspace_envv = envv; 215 imgp->execlabel = NULL; 216 imgp->attr = &attr; 217 imgp->argc = imgp->envc = 0; 218 imgp->argv0 = NULL; 219 imgp->entry_addr = 0; 220 imgp->vmspace_destroyed = 0; 221 imgp->interpreted = 0; 222 imgp->interpreter_name[0] = '\0'; 223 imgp->auxargs = NULL; 224 imgp->vp = NULL; 225 imgp->object = NULL; 226 imgp->firstpage = NULL; 227 imgp->ps_strings = 0; 228 imgp->auxarg_size = 0; 229 230 #ifdef MAC 231 error = mac_execve_enter(imgp, mac_p, &execlabel); 232 if (error) { 233 mtx_lock(&Giant); 234 goto exec_fail; 235 } 236 #endif 237 238 /* 239 * Allocate temporary demand zeroed space for argument and 240 * environment strings 241 */ 242 imgp->stringbase = (char *)kmem_alloc_wait(exec_map, ARG_MAX + 243 PAGE_SIZE); 244 if (imgp->stringbase == NULL) { 245 error = ENOMEM; 246 mtx_lock(&Giant); 247 goto exec_fail; 248 } 249 imgp->stringp = imgp->stringbase; 250 imgp->stringspace = ARG_MAX; 251 imgp->image_header = imgp->stringbase + ARG_MAX; 252 253 /* 254 * Translate the file name. namei() returns a vnode pointer 255 * in ni_vp amoung other things. 256 */ 257 ndp = &nd; 258 NDINIT(ndp, LOOKUP, LOCKLEAF | FOLLOW | SAVENAME, 259 UIO_USERSPACE, fname, td); 260 261 mtx_lock(&Giant); 262 interpret: 263 264 error = namei(ndp); 265 if (error) { 266 kmem_free_wakeup(exec_map, (vm_offset_t)imgp->stringbase, 267 ARG_MAX + PAGE_SIZE); 268 goto exec_fail; 269 } 270 271 imgp->vp = ndp->ni_vp; 272 imgp->fname = fname; 273 274 /* 275 * Check file permissions (also 'opens' file) 276 */ 277 error = exec_check_permissions(imgp); 278 if (error) 279 goto exec_fail_dealloc; 280 281 if (VOP_GETVOBJECT(imgp->vp, &imgp->object) == 0) 282 vm_object_reference(imgp->object); 283 284 /* 285 * Set VV_TEXT now so no one can write to the executable while we're 286 * activating it. 287 * 288 * Remember if this was set before and unset it in case this is not 289 * actually an executable image. 290 */ 291 textset = imgp->vp->v_vflag & VV_TEXT; 292 imgp->vp->v_vflag |= VV_TEXT; 293 294 error = exec_map_first_page(imgp); 295 if (error) 296 goto exec_fail_dealloc; 297 298 /* 299 * If the current process has a special image activator it 300 * wants to try first, call it. For example, emulating shell 301 * scripts differently. 302 */ 303 error = -1; 304 if ((img_first = imgp->proc->p_sysent->sv_imgact_try) != NULL) 305 error = img_first(imgp); 306 307 /* 308 * Loop through the list of image activators, calling each one. 309 * An activator returns -1 if there is no match, 0 on success, 310 * and an error otherwise. 311 */ 312 for (i = 0; error == -1 && execsw[i]; ++i) { 313 if (execsw[i]->ex_imgact == NULL || 314 execsw[i]->ex_imgact == img_first) { 315 continue; 316 } 317 error = (*execsw[i]->ex_imgact)(imgp); 318 } 319 320 if (error) { 321 if (error == -1) { 322 if (textset == 0) 323 imgp->vp->v_vflag &= ~VV_TEXT; 324 error = ENOEXEC; 325 } 326 goto exec_fail_dealloc; 327 } 328 329 /* 330 * Special interpreter operation, cleanup and loop up to try to 331 * activate the interpreter. 332 */ 333 if (imgp->interpreted) { 334 exec_unmap_first_page(imgp); 335 /* 336 * VV_TEXT needs to be unset for scripts. There is a short 337 * period before we determine that something is a script where 338 * VV_TEXT will be set. The vnode lock is held over this 339 * entire period so nothing should illegitimately be blocked. 340 */ 341 imgp->vp->v_vflag &= ~VV_TEXT; 342 /* free name buffer and old vnode */ 343 NDFREE(ndp, NDF_ONLY_PNBUF); 344 #ifdef MAC 345 mac_init_vnode_label(&interplabel); 346 mac_copy_vnode_label(&ndp->ni_vp->v_label, &interplabel); 347 interplabelvalid = 1; 348 #endif 349 vput(ndp->ni_vp); 350 vm_object_deallocate(imgp->object); 351 imgp->object = NULL; 352 /* set new name to that of the interpreter */ 353 NDINIT(ndp, LOOKUP, LOCKLEAF | FOLLOW | SAVENAME, 354 UIO_SYSSPACE, imgp->interpreter_name, td); 355 goto interpret; 356 } 357 358 /* 359 * Copy out strings (args and env) and initialize stack base 360 */ 361 if (p->p_sysent->sv_copyout_strings) 362 stack_base = (*p->p_sysent->sv_copyout_strings)(imgp); 363 else 364 stack_base = exec_copyout_strings(imgp); 365 366 /* 367 * If custom stack fixup routine present for this process 368 * let it do the stack setup. 369 * Else stuff argument count as first item on stack 370 */ 371 if (p->p_sysent->sv_fixup) 372 (*p->p_sysent->sv_fixup)(&stack_base, imgp); 373 else 374 suword(--stack_base, imgp->argc); 375 376 /* 377 * For security and other reasons, the file descriptor table cannot 378 * be shared after an exec. 379 */ 380 FILEDESC_LOCK(p->p_fd); 381 if (p->p_fd->fd_refcnt > 1) { 382 struct filedesc *tmp; 383 384 tmp = fdcopy(td->td_proc->p_fd); 385 FILEDESC_UNLOCK(p->p_fd); 386 fdfree(td); 387 p->p_fd = tmp; 388 } else 389 FILEDESC_UNLOCK(p->p_fd); 390 391 /* 392 * Malloc things before we need locks. 393 */ 394 newcred = crget(); 395 euip = uifind(attr.va_uid); 396 i = imgp->endargs - imgp->stringbase; 397 if (ps_arg_cache_limit >= i + sizeof(struct pargs)) 398 newargs = pargs_alloc(i); 399 400 /* close files on exec */ 401 fdcloseexec(td); 402 403 /* Get a reference to the vnode prior to locking the proc */ 404 VREF(ndp->ni_vp); 405 406 /* 407 * For security and other reasons, signal handlers cannot 408 * be shared after an exec. The new process gets a copy of the old 409 * handlers. In execsigs(), the new process will have its signals 410 * reset. 411 */ 412 PROC_LOCK(p); 413 if (sigacts_shared(p->p_sigacts)) { 414 oldsigacts = p->p_sigacts; 415 PROC_UNLOCK(p); 416 newsigacts = sigacts_alloc(); 417 sigacts_copy(newsigacts, oldsigacts); 418 PROC_LOCK(p); 419 p->p_sigacts = newsigacts; 420 } else 421 oldsigacts = NULL; 422 423 /* Stop profiling */ 424 stopprofclock(p); 425 426 /* reset caught signals */ 427 execsigs(p); 428 429 /* name this process - nameiexec(p, ndp) */ 430 len = min(ndp->ni_cnd.cn_namelen,MAXCOMLEN); 431 bcopy(ndp->ni_cnd.cn_nameptr, p->p_comm, len); 432 p->p_comm[len] = 0; 433 434 /* 435 * mark as execed, wakeup the process that vforked (if any) and tell 436 * it that it now has its own resources back 437 */ 438 p->p_flag |= P_EXEC; 439 if (p->p_pptr && (p->p_flag & P_PPWAIT)) { 440 p->p_flag &= ~P_PPWAIT; 441 wakeup(p->p_pptr); 442 } 443 444 /* 445 * Implement image setuid/setgid. 446 * 447 * Don't honor setuid/setgid if the filesystem prohibits it or if 448 * the process is being traced. 449 * 450 * XXXMAC: For the time being, use NOSUID to also prohibit 451 * transitions on the file system. 452 */ 453 oldcred = p->p_ucred; 454 credential_changing = 0; 455 credential_changing |= (attr.va_mode & VSUID) && oldcred->cr_uid != 456 attr.va_uid; 457 credential_changing |= (attr.va_mode & VSGID) && oldcred->cr_gid != 458 attr.va_gid; 459 #ifdef MAC 460 will_transition = mac_execve_will_transition(oldcred, imgp->vp, 461 interplabelvalid ? &interplabel : NULL, imgp); 462 credential_changing |= will_transition; 463 #endif 464 465 if (credential_changing && 466 (imgp->vp->v_mount->mnt_flag & MNT_NOSUID) == 0 && 467 (p->p_flag & P_TRACED) == 0) { 468 /* 469 * Turn off syscall tracing for set-id programs, except for 470 * root. Record any set-id flags first to make sure that 471 * we do not regain any tracing during a possible block. 472 */ 473 setsugid(p); 474 #ifdef KTRACE 475 if (p->p_tracevp != NULL && suser_cred(oldcred, PRISON_ROOT)) { 476 mtx_lock(&ktrace_mtx); 477 p->p_traceflag = 0; 478 tracevp = p->p_tracevp; 479 p->p_tracevp = NULL; 480 tracecred = p->p_tracecred; 481 p->p_tracecred = NULL; 482 mtx_unlock(&ktrace_mtx); 483 } 484 #endif 485 /* 486 * Close any file descriptors 0..2 that reference procfs, 487 * then make sure file descriptors 0..2 are in use. 488 * 489 * setugidsafety() may call closef() and then pfind() 490 * which may grab the process lock. 491 * fdcheckstd() may call falloc() which may block to 492 * allocate memory, so temporarily drop the process lock. 493 */ 494 PROC_UNLOCK(p); 495 setugidsafety(td); 496 error = fdcheckstd(td); 497 if (error != 0) 498 goto done1; 499 PROC_LOCK(p); 500 /* 501 * Set the new credentials. 502 */ 503 crcopy(newcred, oldcred); 504 if (attr.va_mode & VSUID) 505 change_euid(newcred, euip); 506 if (attr.va_mode & VSGID) 507 change_egid(newcred, attr.va_gid); 508 #ifdef MAC 509 if (will_transition) { 510 mac_execve_transition(oldcred, newcred, imgp->vp, 511 interplabelvalid ? &interplabel : NULL, imgp); 512 } 513 #endif 514 /* 515 * Implement correct POSIX saved-id behavior. 516 * 517 * XXXMAC: Note that the current logic will save the 518 * uid and gid if a MAC domain transition occurs, even 519 * though maybe it shouldn't. 520 */ 521 change_svuid(newcred, newcred->cr_uid); 522 change_svgid(newcred, newcred->cr_gid); 523 p->p_ucred = newcred; 524 newcred = NULL; 525 } else { 526 if (oldcred->cr_uid == oldcred->cr_ruid && 527 oldcred->cr_gid == oldcred->cr_rgid) 528 p->p_flag &= ~P_SUGID; 529 /* 530 * Implement correct POSIX saved-id behavior. 531 * 532 * XXX: It's not clear that the existing behavior is 533 * POSIX-compliant. A number of sources indicate that the 534 * saved uid/gid should only be updated if the new ruid is 535 * not equal to the old ruid, or the new euid is not equal 536 * to the old euid and the new euid is not equal to the old 537 * ruid. The FreeBSD code always updates the saved uid/gid. 538 * Also, this code uses the new (replaced) euid and egid as 539 * the source, which may or may not be the right ones to use. 540 */ 541 if (oldcred->cr_svuid != oldcred->cr_uid || 542 oldcred->cr_svgid != oldcred->cr_gid) { 543 crcopy(newcred, oldcred); 544 change_svuid(newcred, newcred->cr_uid); 545 change_svgid(newcred, newcred->cr_gid); 546 p->p_ucred = newcred; 547 newcred = NULL; 548 } 549 } 550 551 /* 552 * Store the vp for use in procfs. This vnode was referenced prior 553 * to locking the proc lock. 554 */ 555 textvp = p->p_textvp; 556 p->p_textvp = ndp->ni_vp; 557 558 /* 559 * Notify others that we exec'd, and clear the P_INEXEC flag 560 * as we're now a bona fide freshly-execed process. 561 */ 562 KNOTE(&p->p_klist, NOTE_EXEC); 563 p->p_flag &= ~P_INEXEC; 564 565 /* 566 * If tracing the process, trap to debugger so breakpoints 567 * can be set before the program executes. 568 */ 569 if (p->p_flag & P_TRACED) 570 psignal(p, SIGTRAP); 571 572 /* clear "fork but no exec" flag, as we _are_ execing */ 573 p->p_acflag &= ~AFORK; 574 575 /* Free any previous argument cache */ 576 oldargs = p->p_args; 577 p->p_args = NULL; 578 579 /* Cache arguments if they fit inside our allowance */ 580 if (ps_arg_cache_limit >= i + sizeof(struct pargs)) { 581 bcopy(imgp->stringbase, newargs->ar_args, i); 582 p->p_args = newargs; 583 newargs = NULL; 584 } 585 PROC_UNLOCK(p); 586 587 /* Set values passed into the program in registers. */ 588 if (p->p_sysent->sv_setregs) 589 (*p->p_sysent->sv_setregs)(td, imgp->entry_addr, 590 (u_long)(uintptr_t)stack_base, imgp->ps_strings); 591 else 592 exec_setregs(td, imgp->entry_addr, 593 (u_long)(uintptr_t)stack_base, imgp->ps_strings); 594 595 done1: 596 /* 597 * Free any resources malloc'd earlier that we didn't use. 598 */ 599 uifree(euip); 600 if (newcred == NULL) 601 crfree(oldcred); 602 else 603 crfree(newcred); 604 /* 605 * Handle deferred decrement of ref counts. 606 */ 607 if (textvp != NULL) 608 vrele(textvp); 609 if (ndp->ni_vp && error != 0) 610 vrele(ndp->ni_vp); 611 #ifdef KTRACE 612 if (tracevp != NULL) 613 vrele(tracevp); 614 if (tracecred != NULL) 615 crfree(tracecred); 616 #endif 617 if (oldargs != NULL) 618 pargs_drop(oldargs); 619 if (newargs != NULL) 620 pargs_drop(newargs); 621 if (oldsigacts != NULL) 622 sigacts_free(oldsigacts); 623 624 exec_fail_dealloc: 625 626 /* 627 * free various allocated resources 628 */ 629 if (imgp->firstpage) 630 exec_unmap_first_page(imgp); 631 632 if (imgp->vp) { 633 NDFREE(ndp, NDF_ONLY_PNBUF); 634 vput(imgp->vp); 635 } 636 637 if (imgp->stringbase != NULL) 638 kmem_free_wakeup(exec_map, (vm_offset_t)imgp->stringbase, 639 ARG_MAX + PAGE_SIZE); 640 641 if (imgp->object) 642 vm_object_deallocate(imgp->object); 643 644 if (error == 0) { 645 /* 646 * Stop the process here if its stop event mask has 647 * the S_EXEC bit set. 648 */ 649 STOPEVENT(p, S_EXEC, 0); 650 goto done2; 651 } 652 653 exec_fail: 654 /* we're done here, clear P_INEXEC */ 655 PROC_LOCK(p); 656 p->p_flag &= ~P_INEXEC; 657 PROC_UNLOCK(p); 658 659 if (imgp->vmspace_destroyed) { 660 /* sorry, no more process anymore. exit gracefully */ 661 #ifdef MAC 662 mac_execve_exit(imgp); 663 if (interplabelvalid) 664 mac_destroy_vnode_label(&interplabel); 665 #endif 666 exit1(td, W_EXITCODE(0, SIGABRT)); 667 /* NOT REACHED */ 668 error = 0; 669 } 670 done2: 671 #ifdef MAC 672 mac_execve_exit(imgp); 673 if (interplabelvalid) 674 mac_destroy_vnode_label(&interplabel); 675 #endif 676 mtx_unlock(&Giant); 677 return (error); 678 } 679 680 #ifndef _SYS_SYSPROTO_H_ 681 struct execve_args { 682 char *fname; 683 char **argv; 684 char **envv; 685 }; 686 #endif 687 688 /* 689 * MPSAFE 690 */ 691 int 692 execve(td, uap) 693 struct thread *td; 694 struct execve_args /* { 695 char *fname; 696 char **argv; 697 char **envv; 698 } */ *uap; 699 { 700 701 return (kern_execve(td, uap->fname, uap->argv, uap->envv, NULL)); 702 } 703 704 #ifndef _SYS_SYSPROTO_H_ 705 struct __mac_execve_args { 706 char *fname; 707 char **argv; 708 char **envv; 709 struct mac *mac_p; 710 }; 711 #endif 712 713 /* 714 * MPSAFE 715 */ 716 int 717 __mac_execve(td, uap) 718 struct thread *td; 719 struct __mac_execve_args /* { 720 char *fname; 721 char **argv; 722 char **envv; 723 struct mac *mac_p; 724 } */ *uap; 725 { 726 727 #ifdef MAC 728 return (kern_execve(td, uap->fname, uap->argv, uap->envv, 729 uap->mac_p)); 730 #else 731 return (ENOSYS); 732 #endif 733 } 734 735 int 736 exec_map_first_page(imgp) 737 struct image_params *imgp; 738 { 739 int rv, i; 740 int initial_pagein; 741 vm_page_t ma[VM_INITIAL_PAGEIN]; 742 vm_object_t object; 743 744 GIANT_REQUIRED; 745 746 if (imgp->firstpage) { 747 exec_unmap_first_page(imgp); 748 } 749 750 VOP_GETVOBJECT(imgp->vp, &object); 751 VM_OBJECT_LOCK(object); 752 ma[0] = vm_page_grab(object, 0, VM_ALLOC_NORMAL | VM_ALLOC_RETRY); 753 vm_page_lock_queues(); 754 if ((ma[0]->valid & VM_PAGE_BITS_ALL) != VM_PAGE_BITS_ALL) { 755 vm_page_unlock_queues(); 756 initial_pagein = VM_INITIAL_PAGEIN; 757 if (initial_pagein > object->size) 758 initial_pagein = object->size; 759 for (i = 1; i < initial_pagein; i++) { 760 if ((ma[i] = vm_page_lookup(object, i)) != NULL) { 761 vm_page_lock_queues(); 762 if ((ma[i]->flags & PG_BUSY) || ma[i]->busy) { 763 vm_page_unlock_queues(); 764 break; 765 } 766 if (ma[i]->valid) { 767 vm_page_unlock_queues(); 768 break; 769 } 770 vm_page_busy(ma[i]); 771 vm_page_unlock_queues(); 772 } else { 773 ma[i] = vm_page_alloc(object, i, 774 VM_ALLOC_NORMAL); 775 if (ma[i] == NULL) 776 break; 777 } 778 } 779 initial_pagein = i; 780 rv = vm_pager_get_pages(object, ma, initial_pagein, 0); 781 ma[0] = vm_page_lookup(object, 0); 782 vm_page_lock_queues(); 783 if ((rv != VM_PAGER_OK) || (ma[0] == NULL) || 784 (ma[0]->valid == 0)) { 785 if (ma[0]) { 786 pmap_remove_all(ma[0]); 787 vm_page_free(ma[0]); 788 } 789 vm_page_unlock_queues(); 790 VM_OBJECT_UNLOCK(object); 791 return (EIO); 792 } 793 } 794 VM_OBJECT_UNLOCK(object); 795 vm_page_wire(ma[0]); 796 vm_page_wakeup(ma[0]); 797 vm_page_unlock_queues(); 798 799 pmap_qenter((vm_offset_t)imgp->image_header, ma, 1); 800 imgp->firstpage = ma[0]; 801 802 return (0); 803 } 804 805 void 806 exec_unmap_first_page(imgp) 807 struct image_params *imgp; 808 { 809 GIANT_REQUIRED; 810 811 if (imgp->firstpage) { 812 pmap_qremove((vm_offset_t)imgp->image_header, 1); 813 vm_page_lock_queues(); 814 vm_page_unwire(imgp->firstpage, 1); 815 vm_page_unlock_queues(); 816 imgp->firstpage = NULL; 817 } 818 } 819 820 /* 821 * Destroy old address space, and allocate a new stack 822 * The new stack is only SGROWSIZ large because it is grown 823 * automatically in trap.c. 824 */ 825 int 826 exec_new_vmspace(imgp, sv) 827 struct image_params *imgp; 828 struct sysentvec *sv; 829 { 830 int error; 831 struct proc *p = imgp->proc; 832 struct vmspace *vmspace = p->p_vmspace; 833 vm_offset_t stack_addr; 834 vm_map_t map; 835 836 GIANT_REQUIRED; 837 838 stack_addr = sv->sv_usrstack - maxssiz; 839 840 imgp->vmspace_destroyed = 1; 841 842 EVENTHANDLER_INVOKE(process_exec, p); 843 844 /* 845 * Here is as good a place as any to do any resource limit cleanups. 846 * This is needed if a 64 bit binary exec's a 32 bit binary - the 847 * data size limit may need to be changed to a value that makes 848 * sense for the 32 bit binary. 849 */ 850 if (sv->sv_fixlimits) 851 sv->sv_fixlimits(imgp); 852 853 /* 854 * Blow away entire process VM, if address space not shared, 855 * otherwise, create a new VM space so that other threads are 856 * not disrupted 857 */ 858 map = &vmspace->vm_map; 859 if (vmspace->vm_refcnt == 1 && vm_map_min(map) == sv->sv_minuser && 860 vm_map_max(map) == sv->sv_maxuser) { 861 shmexit(vmspace); 862 vm_page_lock_queues(); 863 pmap_remove_pages(vmspace_pmap(vmspace), vm_map_min(map), 864 vm_map_max(map)); 865 vm_page_unlock_queues(); 866 vm_map_remove(map, vm_map_min(map), vm_map_max(map)); 867 } else { 868 vmspace_exec(p, sv->sv_minuser, sv->sv_maxuser); 869 vmspace = p->p_vmspace; 870 map = &vmspace->vm_map; 871 } 872 873 /* Allocate a new stack */ 874 error = vm_map_stack(map, stack_addr, (vm_size_t)maxssiz, 875 sv->sv_stackprot, VM_PROT_ALL, 0); 876 if (error) 877 return (error); 878 879 #ifdef __ia64__ 880 { 881 /* 882 * Allocate backing store. We really need something 883 * similar to vm_map_stack which can allow the backing 884 * store to grow upwards. This will do for now. 885 */ 886 vm_offset_t bsaddr; 887 bsaddr = p->p_sysent->sv_usrstack - 2 * maxssiz; 888 error = vm_map_find(map, 0, 0, &bsaddr, 889 regstkpages * PAGE_SIZE, 0, VM_PROT_ALL, VM_PROT_ALL, 0); 890 FIRST_THREAD_IN_PROC(p)->td_md.md_bspstore = bsaddr; 891 } 892 #endif 893 894 /* vm_ssize and vm_maxsaddr are somewhat antiquated concepts in the 895 * VM_STACK case, but they are still used to monitor the size of the 896 * process stack so we can check the stack rlimit. 897 */ 898 vmspace->vm_ssize = sgrowsiz >> PAGE_SHIFT; 899 vmspace->vm_maxsaddr = (char *)sv->sv_usrstack - maxssiz; 900 901 return (0); 902 } 903 904 /* 905 * Copy out argument and environment strings from the old process 906 * address space into the temporary string buffer. 907 */ 908 int 909 exec_extract_strings(imgp) 910 struct image_params *imgp; 911 { 912 char **argv, **envv; 913 char *argp, *envp; 914 int error; 915 size_t length; 916 917 /* 918 * extract arguments first 919 */ 920 921 argv = imgp->userspace_argv; 922 923 if (argv) { 924 argp = (caddr_t)(intptr_t)fuword(argv); 925 if (argp == (caddr_t)-1) 926 return (EFAULT); 927 if (argp) 928 argv++; 929 if (imgp->argv0) 930 argp = imgp->argv0; 931 if (argp) { 932 do { 933 if (argp == (caddr_t)-1) 934 return (EFAULT); 935 if ((error = copyinstr(argp, imgp->stringp, 936 imgp->stringspace, &length))) { 937 if (error == ENAMETOOLONG) 938 return (E2BIG); 939 return (error); 940 } 941 imgp->stringspace -= length; 942 imgp->stringp += length; 943 imgp->argc++; 944 } while ((argp = (caddr_t)(intptr_t)fuword(argv++))); 945 } 946 } 947 948 imgp->endargs = imgp->stringp; 949 950 /* 951 * extract environment strings 952 */ 953 954 envv = imgp->userspace_envv; 955 956 if (envv) { 957 while ((envp = (caddr_t)(intptr_t)fuword(envv++))) { 958 if (envp == (caddr_t)-1) 959 return (EFAULT); 960 if ((error = copyinstr(envp, imgp->stringp, 961 imgp->stringspace, &length))) { 962 if (error == ENAMETOOLONG) 963 return (E2BIG); 964 return (error); 965 } 966 imgp->stringspace -= length; 967 imgp->stringp += length; 968 imgp->envc++; 969 } 970 } 971 972 return (0); 973 } 974 975 /* 976 * Copy strings out to the new process address space, constructing 977 * new arg and env vector tables. Return a pointer to the base 978 * so that it can be used as the initial stack pointer. 979 */ 980 register_t * 981 exec_copyout_strings(imgp) 982 struct image_params *imgp; 983 { 984 int argc, envc; 985 char **vectp; 986 char *stringp, *destp; 987 register_t *stack_base; 988 struct ps_strings *arginfo; 989 struct proc *p; 990 int szsigcode; 991 992 /* 993 * Calculate string base and vector table pointers. 994 * Also deal with signal trampoline code for this exec type. 995 */ 996 p = imgp->proc; 997 szsigcode = 0; 998 arginfo = (struct ps_strings *)p->p_sysent->sv_psstrings; 999 if (p->p_sysent->sv_szsigcode != NULL) 1000 szsigcode = *(p->p_sysent->sv_szsigcode); 1001 destp = (caddr_t)arginfo - szsigcode - SPARE_USRSPACE - 1002 roundup((ARG_MAX - imgp->stringspace), sizeof(char *)); 1003 1004 /* 1005 * install sigcode 1006 */ 1007 if (szsigcode) 1008 copyout(p->p_sysent->sv_sigcode, ((caddr_t)arginfo - 1009 szsigcode), szsigcode); 1010 1011 /* 1012 * If we have a valid auxargs ptr, prepare some room 1013 * on the stack. 1014 */ 1015 if (imgp->auxargs) { 1016 /* 1017 * 'AT_COUNT*2' is size for the ELF Auxargs data. This is for 1018 * lower compatibility. 1019 */ 1020 imgp->auxarg_size = (imgp->auxarg_size) ? imgp->auxarg_size : 1021 (AT_COUNT * 2); 1022 /* 1023 * The '+ 2' is for the null pointers at the end of each of 1024 * the arg and env vector sets,and imgp->auxarg_size is room 1025 * for argument of Runtime loader. 1026 */ 1027 vectp = (char **)(destp - (imgp->argc + imgp->envc + 2 + 1028 imgp->auxarg_size) * sizeof(char *)); 1029 1030 } else 1031 /* 1032 * The '+ 2' is for the null pointers at the end of each of 1033 * the arg and env vector sets 1034 */ 1035 vectp = (char **)(destp - (imgp->argc + imgp->envc + 2) * 1036 sizeof(char *)); 1037 1038 /* 1039 * vectp also becomes our initial stack base 1040 */ 1041 stack_base = (register_t *)vectp; 1042 1043 stringp = imgp->stringbase; 1044 argc = imgp->argc; 1045 envc = imgp->envc; 1046 1047 /* 1048 * Copy out strings - arguments and environment. 1049 */ 1050 copyout(stringp, destp, ARG_MAX - imgp->stringspace); 1051 1052 /* 1053 * Fill in "ps_strings" struct for ps, w, etc. 1054 */ 1055 suword(&arginfo->ps_argvstr, (long)(intptr_t)vectp); 1056 suword(&arginfo->ps_nargvstr, argc); 1057 1058 /* 1059 * Fill in argument portion of vector table. 1060 */ 1061 for (; argc > 0; --argc) { 1062 suword(vectp++, (long)(intptr_t)destp); 1063 while (*stringp++ != 0) 1064 destp++; 1065 destp++; 1066 } 1067 1068 /* a null vector table pointer separates the argp's from the envp's */ 1069 suword(vectp++, 0); 1070 1071 suword(&arginfo->ps_envstr, (long)(intptr_t)vectp); 1072 suword(&arginfo->ps_nenvstr, envc); 1073 1074 /* 1075 * Fill in environment portion of vector table. 1076 */ 1077 for (; envc > 0; --envc) { 1078 suword(vectp++, (long)(intptr_t)destp); 1079 while (*stringp++ != 0) 1080 destp++; 1081 destp++; 1082 } 1083 1084 /* end of vector table is a null pointer */ 1085 suword(vectp, 0); 1086 1087 return (stack_base); 1088 } 1089 1090 /* 1091 * Check permissions of file to execute. 1092 * Called with imgp->vp locked. 1093 * Return 0 for success or error code on failure. 1094 */ 1095 int 1096 exec_check_permissions(imgp) 1097 struct image_params *imgp; 1098 { 1099 struct vnode *vp = imgp->vp; 1100 struct vattr *attr = imgp->attr; 1101 struct thread *td; 1102 int error; 1103 1104 td = curthread; /* XXXKSE */ 1105 1106 /* Get file attributes */ 1107 error = VOP_GETATTR(vp, attr, td->td_ucred, td); 1108 if (error) 1109 return (error); 1110 1111 #ifdef MAC 1112 error = mac_check_vnode_exec(td->td_ucred, imgp->vp, imgp); 1113 if (error) 1114 return (error); 1115 #endif 1116 1117 /* 1118 * 1) Check if file execution is disabled for the filesystem that this 1119 * file resides on. 1120 * 2) Insure that at least one execute bit is on - otherwise root 1121 * will always succeed, and we don't want to happen unless the 1122 * file really is executable. 1123 * 3) Insure that the file is a regular file. 1124 */ 1125 if ((vp->v_mount->mnt_flag & MNT_NOEXEC) || 1126 ((attr->va_mode & 0111) == 0) || 1127 (attr->va_type != VREG)) 1128 return (EACCES); 1129 1130 /* 1131 * Zero length files can't be exec'd 1132 */ 1133 if (attr->va_size == 0) 1134 return (ENOEXEC); 1135 1136 /* 1137 * Check for execute permission to file based on current credentials. 1138 */ 1139 error = VOP_ACCESS(vp, VEXEC, td->td_ucred, td); 1140 if (error) 1141 return (error); 1142 1143 /* 1144 * Check number of open-for-writes on the file and deny execution 1145 * if there are any. 1146 */ 1147 if (vp->v_writecount) 1148 return (ETXTBSY); 1149 1150 /* 1151 * Call filesystem specific open routine (which does nothing in the 1152 * general case). 1153 */ 1154 error = VOP_OPEN(vp, FREAD, td->td_ucred, td, -1); 1155 return (error); 1156 } 1157 1158 /* 1159 * Exec handler registration 1160 */ 1161 int 1162 exec_register(execsw_arg) 1163 const struct execsw *execsw_arg; 1164 { 1165 const struct execsw **es, **xs, **newexecsw; 1166 int count = 2; /* New slot and trailing NULL */ 1167 1168 if (execsw) 1169 for (es = execsw; *es; es++) 1170 count++; 1171 newexecsw = malloc(count * sizeof(*es), M_TEMP, M_WAITOK); 1172 if (newexecsw == NULL) 1173 return (ENOMEM); 1174 xs = newexecsw; 1175 if (execsw) 1176 for (es = execsw; *es; es++) 1177 *xs++ = *es; 1178 *xs++ = execsw_arg; 1179 *xs = NULL; 1180 if (execsw) 1181 free(execsw, M_TEMP); 1182 execsw = newexecsw; 1183 return (0); 1184 } 1185 1186 int 1187 exec_unregister(execsw_arg) 1188 const struct execsw *execsw_arg; 1189 { 1190 const struct execsw **es, **xs, **newexecsw; 1191 int count = 1; 1192 1193 if (execsw == NULL) 1194 panic("unregister with no handlers left?\n"); 1195 1196 for (es = execsw; *es; es++) { 1197 if (*es == execsw_arg) 1198 break; 1199 } 1200 if (*es == NULL) 1201 return (ENOENT); 1202 for (es = execsw; *es; es++) 1203 if (*es != execsw_arg) 1204 count++; 1205 newexecsw = malloc(count * sizeof(*es), M_TEMP, M_WAITOK); 1206 if (newexecsw == NULL) 1207 return (ENOMEM); 1208 xs = newexecsw; 1209 for (es = execsw; *es; es++) 1210 if (*es != execsw_arg) 1211 *xs++ = *es; 1212 *xs = NULL; 1213 if (execsw) 1214 free(execsw, M_TEMP); 1215 execsw = newexecsw; 1216 return (0); 1217 } 1218