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