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/sf_buf.h> 55 #include <sys/sysent.h> 56 #include <sys/shm.h> 57 #include <sys/sysctl.h> 58 #include <sys/user.h> 59 #include <sys/vnode.h> 60 #ifdef KTRACE 61 #include <sys/ktrace.h> 62 #endif 63 64 #include <vm/vm.h> 65 #include <vm/vm_param.h> 66 #include <vm/pmap.h> 67 #include <vm/vm_page.h> 68 #include <vm/vm_map.h> 69 #include <vm/vm_kern.h> 70 #include <vm/vm_extern.h> 71 #include <vm/vm_object.h> 72 #include <vm/vm_pager.h> 73 74 #include <machine/reg.h> 75 76 MALLOC_DEFINE(M_PARGS, "proc-args", "Process arguments"); 77 78 static int sysctl_kern_ps_strings(SYSCTL_HANDLER_ARGS); 79 static int sysctl_kern_usrstack(SYSCTL_HANDLER_ARGS); 80 static int sysctl_kern_stackprot(SYSCTL_HANDLER_ARGS); 81 static int kern_execve(struct thread *td, char *fname, char **argv, 82 char **envv, struct mac *mac_p); 83 84 /* XXX This should be vm_size_t. */ 85 SYSCTL_PROC(_kern, KERN_PS_STRINGS, ps_strings, CTLTYPE_ULONG|CTLFLAG_RD, 86 NULL, 0, sysctl_kern_ps_strings, "LU", ""); 87 88 /* XXX This should be vm_size_t. */ 89 SYSCTL_PROC(_kern, KERN_USRSTACK, usrstack, CTLTYPE_ULONG|CTLFLAG_RD, 90 NULL, 0, sysctl_kern_usrstack, "LU", ""); 91 92 SYSCTL_PROC(_kern, OID_AUTO, stackprot, CTLTYPE_INT|CTLFLAG_RD, 93 NULL, 0, sysctl_kern_stackprot, "I", ""); 94 95 u_long ps_arg_cache_limit = PAGE_SIZE / 16; 96 SYSCTL_ULONG(_kern, OID_AUTO, ps_arg_cache_limit, CTLFLAG_RW, 97 &ps_arg_cache_limit, 0, ""); 98 99 static int 100 sysctl_kern_ps_strings(SYSCTL_HANDLER_ARGS) 101 { 102 struct proc *p; 103 int error; 104 105 p = curproc; 106 #if defined(__amd64__) || defined(__ia64__) 107 if (req->oldlen == sizeof(unsigned int)) { 108 unsigned int val; 109 val = (unsigned int)p->p_sysent->sv_psstrings; 110 error = SYSCTL_OUT(req, &val, sizeof(val)); 111 } else 112 #endif 113 error = SYSCTL_OUT(req, &p->p_sysent->sv_psstrings, 114 sizeof(p->p_sysent->sv_psstrings)); 115 return error; 116 } 117 118 static int 119 sysctl_kern_usrstack(SYSCTL_HANDLER_ARGS) 120 { 121 struct proc *p; 122 int error; 123 124 p = curproc; 125 #if defined(__amd64__) || defined(__ia64__) 126 if (req->oldlen == sizeof(unsigned int)) { 127 unsigned int val; 128 val = (unsigned int)p->p_sysent->sv_usrstack; 129 error = SYSCTL_OUT(req, &val, sizeof(val)); 130 } else 131 #endif 132 error = SYSCTL_OUT(req, &p->p_sysent->sv_usrstack, 133 sizeof(p->p_sysent->sv_usrstack)); 134 return error; 135 } 136 137 static int 138 sysctl_kern_stackprot(SYSCTL_HANDLER_ARGS) 139 { 140 struct proc *p; 141 142 p = curproc; 143 return (SYSCTL_OUT(req, &p->p_sysent->sv_stackprot, 144 sizeof(p->p_sysent->sv_stackprot))); 145 } 146 147 /* 148 * Each of the items is a pointer to a `const struct execsw', hence the 149 * double pointer here. 150 */ 151 static const struct execsw **execsw; 152 153 #ifndef _SYS_SYSPROTO_H_ 154 struct execve_args { 155 char *fname; 156 char **argv; 157 char **envv; 158 }; 159 #endif 160 161 /* 162 * MPSAFE 163 */ 164 int 165 execve(td, uap) 166 struct thread *td; 167 struct execve_args /* { 168 char *fname; 169 char **argv; 170 char **envv; 171 } */ *uap; 172 { 173 174 return (kern_execve(td, uap->fname, uap->argv, uap->envv, NULL)); 175 } 176 177 #ifndef _SYS_SYSPROTO_H_ 178 struct __mac_execve_args { 179 char *fname; 180 char **argv; 181 char **envv; 182 struct mac *mac_p; 183 }; 184 #endif 185 186 /* 187 * MPSAFE 188 */ 189 int 190 __mac_execve(td, uap) 191 struct thread *td; 192 struct __mac_execve_args /* { 193 char *fname; 194 char **argv; 195 char **envv; 196 struct mac *mac_p; 197 } */ *uap; 198 { 199 200 #ifdef MAC 201 return (kern_execve(td, uap->fname, uap->argv, uap->envv, 202 uap->mac_p)); 203 #else 204 return (ENOSYS); 205 #endif 206 } 207 208 /* 209 * In-kernel implementation of execve(). All arguments are assumed to be 210 * userspace pointers from the passed thread. 211 * 212 * MPSAFE 213 */ 214 static int 215 kern_execve(td, fname, argv, envv, mac_p) 216 struct thread *td; 217 char *fname; 218 char **argv; 219 char **envv; 220 struct mac *mac_p; 221 { 222 struct proc *p = td->td_proc; 223 struct nameidata nd, *ndp; 224 struct ucred *newcred = NULL, *oldcred; 225 struct uidinfo *euip; 226 register_t *stack_base; 227 int error, len, i; 228 struct image_params image_params, *imgp; 229 struct vattr attr; 230 int (*img_first)(struct image_params *); 231 struct pargs *oldargs = NULL, *newargs = NULL; 232 struct sigacts *oldsigacts, *newsigacts; 233 #ifdef KTRACE 234 struct vnode *tracevp = NULL; 235 struct ucred *tracecred = NULL; 236 #endif 237 struct vnode *textvp = NULL; 238 int credential_changing; 239 int textset; 240 #ifdef MAC 241 struct label *interplabel = NULL; 242 int will_transition; 243 #endif 244 245 imgp = &image_params; 246 247 /* 248 * Lock the process and set the P_INEXEC flag to indicate that 249 * it should be left alone until we're done here. This is 250 * necessary to avoid race conditions - e.g. in ptrace() - 251 * that might allow a local user to illicitly obtain elevated 252 * privileges. 253 */ 254 PROC_LOCK(p); 255 KASSERT((p->p_flag & P_INEXEC) == 0, 256 ("%s(): process already has P_INEXEC flag", __func__)); 257 if (p->p_flag & P_SA || p->p_numthreads > 1) { 258 if (thread_single(SINGLE_EXIT)) { 259 PROC_UNLOCK(p); 260 mtx_unlock(&Giant); 261 return (ERESTART); /* Try again later. */ 262 } 263 /* 264 * If we get here all other threads are dead, 265 * so unset the associated flags and lose KSE mode. 266 */ 267 p->p_flag &= ~P_SA; 268 td->td_mailbox = NULL; 269 td->td_pflags &= ~TDP_SA; 270 thread_single_end(); 271 } 272 p->p_flag |= P_INEXEC; 273 PROC_UNLOCK(p); 274 275 /* 276 * Initialize part of the common data 277 */ 278 imgp->proc = p; 279 imgp->userspace_argv = argv; 280 imgp->userspace_envv = envv; 281 imgp->execlabel = NULL; 282 imgp->attr = &attr; 283 imgp->argc = imgp->envc = 0; 284 imgp->argv0 = NULL; 285 imgp->entry_addr = 0; 286 imgp->vmspace_destroyed = 0; 287 imgp->interpreted = 0; 288 imgp->interpreter_name[0] = '\0'; 289 imgp->auxargs = NULL; 290 imgp->vp = NULL; 291 imgp->object = NULL; 292 imgp->firstpage = NULL; 293 imgp->ps_strings = 0; 294 imgp->auxarg_size = 0; 295 296 #ifdef MAC 297 error = mac_execve_enter(imgp, mac_p); 298 if (error) { 299 mtx_lock(&Giant); 300 goto exec_fail; 301 } 302 #endif 303 304 /* 305 * Allocate temporary demand zeroed space for argument and 306 * environment strings 307 */ 308 imgp->stringbase = (char *)kmem_alloc_wait(exec_map, ARG_MAX); 309 if (imgp->stringbase == NULL) { 310 error = ENOMEM; 311 mtx_lock(&Giant); 312 goto exec_fail; 313 } 314 imgp->stringp = imgp->stringbase; 315 imgp->stringspace = ARG_MAX; 316 imgp->image_header = NULL; 317 318 /* 319 * Translate the file name. namei() returns a vnode pointer 320 * in ni_vp amoung other things. 321 */ 322 ndp = &nd; 323 NDINIT(ndp, LOOKUP, LOCKLEAF | FOLLOW | SAVENAME, 324 UIO_USERSPACE, fname, td); 325 326 mtx_lock(&Giant); 327 interpret: 328 329 error = namei(ndp); 330 if (error) { 331 kmem_free_wakeup(exec_map, (vm_offset_t)imgp->stringbase, 332 ARG_MAX); 333 goto exec_fail; 334 } 335 336 imgp->vp = ndp->ni_vp; 337 imgp->fname = fname; 338 339 /* 340 * Check file permissions (also 'opens' file) 341 */ 342 error = exec_check_permissions(imgp); 343 if (error) 344 goto exec_fail_dealloc; 345 346 if (VOP_GETVOBJECT(imgp->vp, &imgp->object) == 0) 347 vm_object_reference(imgp->object); 348 349 /* 350 * Set VV_TEXT now so no one can write to the executable while we're 351 * activating it. 352 * 353 * Remember if this was set before and unset it in case this is not 354 * actually an executable image. 355 */ 356 textset = imgp->vp->v_vflag & VV_TEXT; 357 imgp->vp->v_vflag |= VV_TEXT; 358 359 error = exec_map_first_page(imgp); 360 if (error) 361 goto exec_fail_dealloc; 362 363 /* 364 * If the current process has a special image activator it 365 * wants to try first, call it. For example, emulating shell 366 * scripts differently. 367 */ 368 error = -1; 369 if ((img_first = imgp->proc->p_sysent->sv_imgact_try) != NULL) 370 error = img_first(imgp); 371 372 /* 373 * Loop through the list of image activators, calling each one. 374 * An activator returns -1 if there is no match, 0 on success, 375 * and an error otherwise. 376 */ 377 for (i = 0; error == -1 && execsw[i]; ++i) { 378 if (execsw[i]->ex_imgact == NULL || 379 execsw[i]->ex_imgact == img_first) { 380 continue; 381 } 382 error = (*execsw[i]->ex_imgact)(imgp); 383 } 384 385 if (error) { 386 if (error == -1) { 387 if (textset == 0) 388 imgp->vp->v_vflag &= ~VV_TEXT; 389 error = ENOEXEC; 390 } 391 goto exec_fail_dealloc; 392 } 393 394 /* 395 * Special interpreter operation, cleanup and loop up to try to 396 * activate the interpreter. 397 */ 398 if (imgp->interpreted) { 399 exec_unmap_first_page(imgp); 400 /* 401 * VV_TEXT needs to be unset for scripts. There is a short 402 * period before we determine that something is a script where 403 * VV_TEXT will be set. The vnode lock is held over this 404 * entire period so nothing should illegitimately be blocked. 405 */ 406 imgp->vp->v_vflag &= ~VV_TEXT; 407 /* free name buffer and old vnode */ 408 NDFREE(ndp, NDF_ONLY_PNBUF); 409 #ifdef MAC 410 interplabel = mac_vnode_label_alloc(); 411 mac_copy_vnode_label(ndp->ni_vp->v_label, interplabel); 412 #endif 413 vput(ndp->ni_vp); 414 vm_object_deallocate(imgp->object); 415 imgp->object = NULL; 416 /* set new name to that of the interpreter */ 417 NDINIT(ndp, LOOKUP, LOCKLEAF | FOLLOW | SAVENAME, 418 UIO_SYSSPACE, imgp->interpreter_name, td); 419 goto interpret; 420 } 421 422 /* 423 * Copy out strings (args and env) and initialize stack base 424 */ 425 if (p->p_sysent->sv_copyout_strings) 426 stack_base = (*p->p_sysent->sv_copyout_strings)(imgp); 427 else 428 stack_base = exec_copyout_strings(imgp); 429 430 /* 431 * If custom stack fixup routine present for this process 432 * let it do the stack setup. 433 * Else stuff argument count as first item on stack 434 */ 435 if (p->p_sysent->sv_fixup != NULL) 436 (*p->p_sysent->sv_fixup)(&stack_base, imgp); 437 else 438 suword(--stack_base, imgp->argc); 439 440 /* 441 * For security and other reasons, the file descriptor table cannot 442 * be shared after an exec. 443 */ 444 FILEDESC_LOCK(p->p_fd); 445 if (p->p_fd->fd_refcnt > 1) { 446 struct filedesc *tmp; 447 448 tmp = fdcopy(td->td_proc->p_fd); 449 FILEDESC_UNLOCK(p->p_fd); 450 fdfree(td); 451 p->p_fd = tmp; 452 } else 453 FILEDESC_UNLOCK(p->p_fd); 454 455 /* 456 * Malloc things before we need locks. 457 */ 458 newcred = crget(); 459 euip = uifind(attr.va_uid); 460 i = imgp->endargs - imgp->stringbase; 461 if (ps_arg_cache_limit >= i + sizeof(struct pargs)) 462 newargs = pargs_alloc(i); 463 464 /* close files on exec */ 465 fdcloseexec(td); 466 467 /* Get a reference to the vnode prior to locking the proc */ 468 VREF(ndp->ni_vp); 469 470 /* 471 * For security and other reasons, signal handlers cannot 472 * be shared after an exec. The new process gets a copy of the old 473 * handlers. In execsigs(), the new process will have its signals 474 * reset. 475 */ 476 PROC_LOCK(p); 477 if (sigacts_shared(p->p_sigacts)) { 478 oldsigacts = p->p_sigacts; 479 PROC_UNLOCK(p); 480 newsigacts = sigacts_alloc(); 481 sigacts_copy(newsigacts, oldsigacts); 482 PROC_LOCK(p); 483 p->p_sigacts = newsigacts; 484 } else 485 oldsigacts = NULL; 486 487 /* Stop profiling */ 488 stopprofclock(p); 489 490 /* reset caught signals */ 491 execsigs(p); 492 493 /* name this process - nameiexec(p, ndp) */ 494 len = min(ndp->ni_cnd.cn_namelen,MAXCOMLEN); 495 bcopy(ndp->ni_cnd.cn_nameptr, p->p_comm, len); 496 p->p_comm[len] = 0; 497 498 /* 499 * mark as execed, wakeup the process that vforked (if any) and tell 500 * it that it now has its own resources back 501 */ 502 p->p_flag |= P_EXEC; 503 if (p->p_pptr && (p->p_flag & P_PPWAIT)) { 504 p->p_flag &= ~P_PPWAIT; 505 wakeup(p->p_pptr); 506 } 507 508 /* 509 * Implement image setuid/setgid. 510 * 511 * Don't honor setuid/setgid if the filesystem prohibits it or if 512 * the process is being traced. 513 * 514 * XXXMAC: For the time being, use NOSUID to also prohibit 515 * transitions on the file system. 516 */ 517 oldcred = p->p_ucred; 518 credential_changing = 0; 519 credential_changing |= (attr.va_mode & VSUID) && oldcred->cr_uid != 520 attr.va_uid; 521 credential_changing |= (attr.va_mode & VSGID) && oldcred->cr_gid != 522 attr.va_gid; 523 #ifdef MAC 524 will_transition = mac_execve_will_transition(oldcred, imgp->vp, 525 interplabel, imgp); 526 credential_changing |= will_transition; 527 #endif 528 529 if (credential_changing && 530 (imgp->vp->v_mount->mnt_flag & MNT_NOSUID) == 0 && 531 (p->p_flag & P_TRACED) == 0) { 532 /* 533 * Turn off syscall tracing for set-id programs, except for 534 * root. Record any set-id flags first to make sure that 535 * we do not regain any tracing during a possible block. 536 */ 537 setsugid(p); 538 #ifdef KTRACE 539 if (p->p_tracevp != NULL && suser_cred(oldcred, PRISON_ROOT)) { 540 mtx_lock(&ktrace_mtx); 541 p->p_traceflag = 0; 542 tracevp = p->p_tracevp; 543 p->p_tracevp = NULL; 544 tracecred = p->p_tracecred; 545 p->p_tracecred = NULL; 546 mtx_unlock(&ktrace_mtx); 547 } 548 #endif 549 /* 550 * Close any file descriptors 0..2 that reference procfs, 551 * then make sure file descriptors 0..2 are in use. 552 * 553 * setugidsafety() may call closef() and then pfind() 554 * which may grab the process lock. 555 * fdcheckstd() may call falloc() which may block to 556 * allocate memory, so temporarily drop the process lock. 557 */ 558 PROC_UNLOCK(p); 559 setugidsafety(td); 560 error = fdcheckstd(td); 561 if (error != 0) 562 goto done1; 563 PROC_LOCK(p); 564 /* 565 * Set the new credentials. 566 */ 567 crcopy(newcred, oldcred); 568 if (attr.va_mode & VSUID) 569 change_euid(newcred, euip); 570 if (attr.va_mode & VSGID) 571 change_egid(newcred, attr.va_gid); 572 #ifdef MAC 573 if (will_transition) { 574 mac_execve_transition(oldcred, newcred, imgp->vp, 575 interplabel, imgp); 576 } 577 #endif 578 /* 579 * Implement correct POSIX saved-id behavior. 580 * 581 * XXXMAC: Note that the current logic will save the 582 * uid and gid if a MAC domain transition occurs, even 583 * though maybe it shouldn't. 584 */ 585 change_svuid(newcred, newcred->cr_uid); 586 change_svgid(newcred, newcred->cr_gid); 587 p->p_ucred = newcred; 588 newcred = NULL; 589 } else { 590 if (oldcred->cr_uid == oldcred->cr_ruid && 591 oldcred->cr_gid == oldcred->cr_rgid) 592 p->p_flag &= ~P_SUGID; 593 /* 594 * Implement correct POSIX saved-id behavior. 595 * 596 * XXX: It's not clear that the existing behavior is 597 * POSIX-compliant. A number of sources indicate that the 598 * saved uid/gid should only be updated if the new ruid is 599 * not equal to the old ruid, or the new euid is not equal 600 * to the old euid and the new euid is not equal to the old 601 * ruid. The FreeBSD code always updates the saved uid/gid. 602 * Also, this code uses the new (replaced) euid and egid as 603 * the source, which may or may not be the right ones to use. 604 */ 605 if (oldcred->cr_svuid != oldcred->cr_uid || 606 oldcred->cr_svgid != oldcred->cr_gid) { 607 crcopy(newcred, oldcred); 608 change_svuid(newcred, newcred->cr_uid); 609 change_svgid(newcred, newcred->cr_gid); 610 p->p_ucred = newcred; 611 newcred = NULL; 612 } 613 } 614 615 /* 616 * Store the vp for use in procfs. This vnode was referenced prior 617 * to locking the proc lock. 618 */ 619 textvp = p->p_textvp; 620 p->p_textvp = ndp->ni_vp; 621 622 /* 623 * Notify others that we exec'd, and clear the P_INEXEC flag 624 * as we're now a bona fide freshly-execed process. 625 */ 626 KNOTE(&p->p_klist, NOTE_EXEC); 627 p->p_flag &= ~P_INEXEC; 628 629 /* 630 * If tracing the process, trap to debugger so breakpoints 631 * can be set before the program executes. 632 */ 633 if (p->p_flag & P_TRACED) 634 psignal(p, SIGTRAP); 635 636 /* clear "fork but no exec" flag, as we _are_ execing */ 637 p->p_acflag &= ~AFORK; 638 639 /* Free any previous argument cache */ 640 oldargs = p->p_args; 641 p->p_args = NULL; 642 643 /* Cache arguments if they fit inside our allowance */ 644 if (ps_arg_cache_limit >= i + sizeof(struct pargs)) { 645 bcopy(imgp->stringbase, newargs->ar_args, i); 646 p->p_args = newargs; 647 newargs = NULL; 648 } 649 PROC_UNLOCK(p); 650 651 /* Set values passed into the program in registers. */ 652 if (p->p_sysent->sv_setregs) 653 (*p->p_sysent->sv_setregs)(td, imgp->entry_addr, 654 (u_long)(uintptr_t)stack_base, imgp->ps_strings); 655 else 656 exec_setregs(td, imgp->entry_addr, 657 (u_long)(uintptr_t)stack_base, imgp->ps_strings); 658 659 done1: 660 /* 661 * Free any resources malloc'd earlier that we didn't use. 662 */ 663 uifree(euip); 664 if (newcred == NULL) 665 crfree(oldcred); 666 else 667 crfree(newcred); 668 /* 669 * Handle deferred decrement of ref counts. 670 */ 671 if (textvp != NULL) 672 vrele(textvp); 673 if (ndp->ni_vp && error != 0) 674 vrele(ndp->ni_vp); 675 #ifdef KTRACE 676 if (tracevp != NULL) 677 vrele(tracevp); 678 if (tracecred != NULL) 679 crfree(tracecred); 680 #endif 681 if (oldargs != NULL) 682 pargs_drop(oldargs); 683 if (newargs != NULL) 684 pargs_drop(newargs); 685 if (oldsigacts != NULL) 686 sigacts_free(oldsigacts); 687 688 exec_fail_dealloc: 689 690 /* 691 * free various allocated resources 692 */ 693 if (imgp->firstpage != NULL) 694 exec_unmap_first_page(imgp); 695 696 if (imgp->vp != NULL) { 697 NDFREE(ndp, NDF_ONLY_PNBUF); 698 vput(imgp->vp); 699 } 700 701 if (imgp->stringbase != NULL) 702 kmem_free_wakeup(exec_map, (vm_offset_t)imgp->stringbase, 703 ARG_MAX); 704 705 if (imgp->object != NULL) 706 vm_object_deallocate(imgp->object); 707 708 if (error == 0) { 709 /* 710 * Stop the process here if its stop event mask has 711 * the S_EXEC bit set. 712 */ 713 STOPEVENT(p, S_EXEC, 0); 714 goto done2; 715 } 716 717 exec_fail: 718 /* we're done here, clear P_INEXEC */ 719 PROC_LOCK(p); 720 p->p_flag &= ~P_INEXEC; 721 PROC_UNLOCK(p); 722 723 if (imgp->vmspace_destroyed) { 724 /* sorry, no more process anymore. exit gracefully */ 725 #ifdef MAC 726 mac_execve_exit(imgp); 727 if (interplabel != NULL) 728 mac_vnode_label_free(interplabel); 729 #endif 730 exit1(td, W_EXITCODE(0, SIGABRT)); 731 /* NOT REACHED */ 732 error = 0; 733 } 734 done2: 735 #ifdef MAC 736 mac_execve_exit(imgp); 737 if (interplabel != NULL) 738 mac_vnode_label_free(interplabel); 739 #endif 740 mtx_unlock(&Giant); 741 return (error); 742 } 743 744 int 745 exec_map_first_page(imgp) 746 struct image_params *imgp; 747 { 748 int rv, i; 749 int initial_pagein; 750 vm_page_t ma[VM_INITIAL_PAGEIN]; 751 vm_object_t object; 752 753 GIANT_REQUIRED; 754 755 if (imgp->firstpage != NULL) 756 exec_unmap_first_page(imgp); 757 758 VOP_GETVOBJECT(imgp->vp, &object); 759 VM_OBJECT_LOCK(object); 760 ma[0] = vm_page_grab(object, 0, VM_ALLOC_NORMAL | VM_ALLOC_RETRY); 761 if ((ma[0]->valid & VM_PAGE_BITS_ALL) != VM_PAGE_BITS_ALL) { 762 initial_pagein = VM_INITIAL_PAGEIN; 763 if (initial_pagein > object->size) 764 initial_pagein = object->size; 765 for (i = 1; i < initial_pagein; i++) { 766 if ((ma[i] = vm_page_lookup(object, i)) != NULL) { 767 if (ma[i]->valid) 768 break; 769 vm_page_lock_queues(); 770 if ((ma[i]->flags & PG_BUSY) || ma[i]->busy) { 771 vm_page_unlock_queues(); 772 break; 773 } 774 vm_page_busy(ma[i]); 775 vm_page_unlock_queues(); 776 } else { 777 ma[i] = vm_page_alloc(object, i, 778 VM_ALLOC_NORMAL); 779 if (ma[i] == NULL) 780 break; 781 } 782 } 783 initial_pagein = i; 784 rv = vm_pager_get_pages(object, ma, initial_pagein, 0); 785 ma[0] = vm_page_lookup(object, 0); 786 if ((rv != VM_PAGER_OK) || (ma[0] == NULL) || 787 (ma[0]->valid == 0)) { 788 if (ma[0]) { 789 vm_page_lock_queues(); 790 pmap_remove_all(ma[0]); 791 vm_page_free(ma[0]); 792 vm_page_unlock_queues(); 793 } 794 VM_OBJECT_UNLOCK(object); 795 return (EIO); 796 } 797 } 798 vm_page_lock_queues(); 799 vm_page_hold(ma[0]); 800 vm_page_wakeup(ma[0]); 801 vm_page_unlock_queues(); 802 VM_OBJECT_UNLOCK(object); 803 804 imgp->firstpage = sf_buf_alloc(ma[0], 0); 805 imgp->image_header = (char *)sf_buf_kva(imgp->firstpage); 806 807 return (0); 808 } 809 810 void 811 exec_unmap_first_page(imgp) 812 struct image_params *imgp; 813 { 814 vm_page_t m; 815 816 if (imgp->firstpage != NULL) { 817 m = sf_buf_page(imgp->firstpage); 818 sf_buf_free(imgp->firstpage); 819 imgp->firstpage = NULL; 820 vm_page_lock_queues(); 821 vm_page_unhold(m); 822 vm_page_unlock_queues(); 823 } 824 } 825 826 /* 827 * Destroy old address space, and allocate a new stack 828 * The new stack is only SGROWSIZ large because it is grown 829 * automatically in trap.c. 830 */ 831 int 832 exec_new_vmspace(imgp, sv) 833 struct image_params *imgp; 834 struct sysentvec *sv; 835 { 836 int error; 837 struct proc *p = imgp->proc; 838 struct vmspace *vmspace = p->p_vmspace; 839 vm_offset_t stack_addr; 840 vm_map_t map; 841 842 GIANT_REQUIRED; 843 844 imgp->vmspace_destroyed = 1; 845 846 /* Called with Giant held, do not depend on it! */ 847 EVENTHANDLER_INVOKE(process_exec, p); 848 849 /* 850 * Here is as good a place as any to do any resource limit cleanups. 851 * This is needed if a 64 bit binary exec's a 32 bit binary - the 852 * data size limit may need to be changed to a value that makes 853 * sense for the 32 bit binary. 854 */ 855 if (sv->sv_fixlimits != NULL) 856 sv->sv_fixlimits(imgp); 857 858 /* 859 * Blow away entire process VM, if address space not shared, 860 * otherwise, create a new VM space so that other threads are 861 * not disrupted 862 */ 863 map = &vmspace->vm_map; 864 if (vmspace->vm_refcnt == 1 && vm_map_min(map) == sv->sv_minuser && 865 vm_map_max(map) == sv->sv_maxuser) { 866 shmexit(vmspace); 867 pmap_remove_pages(vmspace_pmap(vmspace), vm_map_min(map), 868 vm_map_max(map)); 869 vm_map_remove(map, vm_map_min(map), vm_map_max(map)); 870 } else { 871 vmspace_exec(p, sv->sv_minuser, sv->sv_maxuser); 872 vmspace = p->p_vmspace; 873 map = &vmspace->vm_map; 874 } 875 876 /* Allocate a new stack */ 877 stack_addr = sv->sv_usrstack - maxssiz; 878 error = vm_map_stack(map, stack_addr, (vm_size_t)maxssiz, 879 sv->sv_stackprot, VM_PROT_ALL, MAP_STACK_GROWS_DOWN); 880 if (error) 881 return (error); 882 883 #ifdef __ia64__ 884 /* Allocate a new register stack */ 885 stack_addr = IA64_BACKINGSTORE; 886 error = vm_map_stack(map, stack_addr, (vm_size_t)maxssiz, 887 sv->sv_stackprot, VM_PROT_ALL, MAP_STACK_GROWS_UP); 888 if (error) 889 return (error); 890 #endif 891 892 /* vm_ssize and vm_maxsaddr are somewhat antiquated concepts in the 893 * VM_STACK case, but they are still used to monitor the size of the 894 * process stack so we can check the stack rlimit. 895 */ 896 vmspace->vm_ssize = sgrowsiz >> PAGE_SHIFT; 897 vmspace->vm_maxsaddr = (char *)sv->sv_usrstack - maxssiz; 898 899 return (0); 900 } 901 902 /* 903 * Copy out argument and environment strings from the old process 904 * address space into the temporary string buffer. 905 */ 906 int 907 exec_extract_strings(imgp) 908 struct image_params *imgp; 909 { 910 char **argv, **envv; 911 char *argp, *envp; 912 int error; 913 size_t length; 914 915 /* 916 * extract arguments first 917 */ 918 919 argv = imgp->userspace_argv; 920 921 if (argv) { 922 argp = (caddr_t)(intptr_t)fuword(argv); 923 if (argp == (caddr_t)-1) 924 return (EFAULT); 925 if (argp) 926 argv++; 927 if (imgp->argv0) 928 argp = imgp->argv0; 929 if (argp) { 930 do { 931 if (argp == (caddr_t)-1) 932 return (EFAULT); 933 if ((error = copyinstr(argp, imgp->stringp, 934 imgp->stringspace, &length))) { 935 if (error == ENAMETOOLONG) 936 return (E2BIG); 937 return (error); 938 } 939 imgp->stringspace -= length; 940 imgp->stringp += length; 941 imgp->argc++; 942 } while ((argp = (caddr_t)(intptr_t)fuword(argv++))); 943 } 944 } else 945 return (EFAULT); 946 947 imgp->endargs = imgp->stringp; 948 949 /* 950 * extract environment strings 951 */ 952 953 envv = imgp->userspace_envv; 954 955 if (envv) { 956 while ((envp = (caddr_t)(intptr_t)fuword(envv++))) { 957 if (envp == (caddr_t)-1) 958 return (EFAULT); 959 if ((error = copyinstr(envp, imgp->stringp, 960 imgp->stringspace, &length))) { 961 if (error == ENAMETOOLONG) 962 return (E2BIG); 963 return (error); 964 } 965 imgp->stringspace -= length; 966 imgp->stringp += length; 967 imgp->envc++; 968 } 969 } 970 971 return (0); 972 } 973 974 /* 975 * Copy strings out to the new process address space, constructing 976 * new arg and env vector tables. Return a pointer to the base 977 * so that it can be used as the initial stack pointer. 978 */ 979 register_t * 980 exec_copyout_strings(imgp) 981 struct image_params *imgp; 982 { 983 int argc, envc; 984 char **vectp; 985 char *stringp, *destp; 986 register_t *stack_base; 987 struct ps_strings *arginfo; 988 struct proc *p; 989 int szsigcode; 990 991 /* 992 * Calculate string base and vector table pointers. 993 * Also deal with signal trampoline code for this exec type. 994 */ 995 p = imgp->proc; 996 szsigcode = 0; 997 arginfo = (struct ps_strings *)p->p_sysent->sv_psstrings; 998 if (p->p_sysent->sv_szsigcode != NULL) 999 szsigcode = *(p->p_sysent->sv_szsigcode); 1000 destp = (caddr_t)arginfo - szsigcode - SPARE_USRSPACE - 1001 roundup((ARG_MAX - imgp->stringspace), sizeof(char *)); 1002 1003 /* 1004 * install sigcode 1005 */ 1006 if (szsigcode) 1007 copyout(p->p_sysent->sv_sigcode, ((caddr_t)arginfo - 1008 szsigcode), szsigcode); 1009 1010 /* 1011 * If we have a valid auxargs ptr, prepare some room 1012 * on the stack. 1013 */ 1014 if (imgp->auxargs) { 1015 /* 1016 * 'AT_COUNT*2' is size for the ELF Auxargs data. This is for 1017 * lower compatibility. 1018 */ 1019 imgp->auxarg_size = (imgp->auxarg_size) ? imgp->auxarg_size : 1020 (AT_COUNT * 2); 1021 /* 1022 * The '+ 2' is for the null pointers at the end of each of 1023 * the arg and env vector sets,and imgp->auxarg_size is room 1024 * for argument of Runtime loader. 1025 */ 1026 vectp = (char **)(destp - (imgp->argc + imgp->envc + 2 + 1027 imgp->auxarg_size) * sizeof(char *)); 1028 1029 } else 1030 /* 1031 * The '+ 2' is for the null pointers at the end of each of 1032 * the arg and env vector sets 1033 */ 1034 vectp = (char **)(destp - (imgp->argc + imgp->envc + 2) * 1035 sizeof(char *)); 1036 1037 /* 1038 * vectp also becomes our initial stack base 1039 */ 1040 stack_base = (register_t *)vectp; 1041 1042 stringp = imgp->stringbase; 1043 argc = imgp->argc; 1044 envc = imgp->envc; 1045 1046 /* 1047 * Copy out strings - arguments and environment. 1048 */ 1049 copyout(stringp, destp, ARG_MAX - imgp->stringspace); 1050 1051 /* 1052 * Fill in "ps_strings" struct for ps, w, etc. 1053 */ 1054 suword(&arginfo->ps_argvstr, (long)(intptr_t)vectp); 1055 suword(&arginfo->ps_nargvstr, argc); 1056 1057 /* 1058 * Fill in argument portion of vector table. 1059 */ 1060 for (; argc > 0; --argc) { 1061 suword(vectp++, (long)(intptr_t)destp); 1062 while (*stringp++ != 0) 1063 destp++; 1064 destp++; 1065 } 1066 1067 /* a null vector table pointer separates the argp's from the envp's */ 1068 suword(vectp++, 0); 1069 1070 suword(&arginfo->ps_envstr, (long)(intptr_t)vectp); 1071 suword(&arginfo->ps_nenvstr, envc); 1072 1073 /* 1074 * Fill in environment portion of vector table. 1075 */ 1076 for (; envc > 0; --envc) { 1077 suword(vectp++, (long)(intptr_t)destp); 1078 while (*stringp++ != 0) 1079 destp++; 1080 destp++; 1081 } 1082 1083 /* end of vector table is a null pointer */ 1084 suword(vectp, 0); 1085 1086 return (stack_base); 1087 } 1088 1089 /* 1090 * Check permissions of file to execute. 1091 * Called with imgp->vp locked. 1092 * Return 0 for success or error code on failure. 1093 */ 1094 int 1095 exec_check_permissions(imgp) 1096 struct image_params *imgp; 1097 { 1098 struct vnode *vp = imgp->vp; 1099 struct vattr *attr = imgp->attr; 1100 struct thread *td; 1101 int error; 1102 1103 td = curthread; /* XXXKSE */ 1104 1105 /* Get file attributes */ 1106 error = VOP_GETATTR(vp, attr, td->td_ucred, td); 1107 if (error) 1108 return (error); 1109 1110 #ifdef MAC 1111 error = mac_check_vnode_exec(td->td_ucred, imgp->vp, imgp); 1112 if (error) 1113 return (error); 1114 #endif 1115 1116 /* 1117 * 1) Check if file execution is disabled for the filesystem that this 1118 * file resides on. 1119 * 2) Insure that at least one execute bit is on - otherwise root 1120 * will always succeed, and we don't want to happen unless the 1121 * file really is executable. 1122 * 3) Insure that the file is a regular file. 1123 */ 1124 if ((vp->v_mount->mnt_flag & MNT_NOEXEC) || 1125 ((attr->va_mode & 0111) == 0) || 1126 (attr->va_type != VREG)) 1127 return (EACCES); 1128 1129 /* 1130 * Zero length files can't be exec'd 1131 */ 1132 if (attr->va_size == 0) 1133 return (ENOEXEC); 1134 1135 /* 1136 * Check for execute permission to file based on current credentials. 1137 */ 1138 error = VOP_ACCESS(vp, VEXEC, td->td_ucred, td); 1139 if (error) 1140 return (error); 1141 1142 /* 1143 * Check number of open-for-writes on the file and deny execution 1144 * if there are any. 1145 */ 1146 if (vp->v_writecount) 1147 return (ETXTBSY); 1148 1149 /* 1150 * Call filesystem specific open routine (which does nothing in the 1151 * general case). 1152 */ 1153 error = VOP_OPEN(vp, FREAD, td->td_ucred, td, -1); 1154 return (error); 1155 } 1156 1157 /* 1158 * Exec handler registration 1159 */ 1160 int 1161 exec_register(execsw_arg) 1162 const struct execsw *execsw_arg; 1163 { 1164 const struct execsw **es, **xs, **newexecsw; 1165 int count = 2; /* New slot and trailing NULL */ 1166 1167 if (execsw) 1168 for (es = execsw; *es; es++) 1169 count++; 1170 newexecsw = malloc(count * sizeof(*es), M_TEMP, M_WAITOK); 1171 if (newexecsw == NULL) 1172 return (ENOMEM); 1173 xs = newexecsw; 1174 if (execsw) 1175 for (es = execsw; *es; es++) 1176 *xs++ = *es; 1177 *xs++ = execsw_arg; 1178 *xs = NULL; 1179 if (execsw) 1180 free(execsw, M_TEMP); 1181 execsw = newexecsw; 1182 return (0); 1183 } 1184 1185 int 1186 exec_unregister(execsw_arg) 1187 const struct execsw *execsw_arg; 1188 { 1189 const struct execsw **es, **xs, **newexecsw; 1190 int count = 1; 1191 1192 if (execsw == NULL) 1193 panic("unregister with no handlers left?\n"); 1194 1195 for (es = execsw; *es; es++) { 1196 if (*es == execsw_arg) 1197 break; 1198 } 1199 if (*es == NULL) 1200 return (ENOENT); 1201 for (es = execsw; *es; es++) 1202 if (*es != execsw_arg) 1203 count++; 1204 newexecsw = malloc(count * sizeof(*es), M_TEMP, M_WAITOK); 1205 if (newexecsw == NULL) 1206 return (ENOMEM); 1207 xs = newexecsw; 1208 for (es = execsw; *es; es++) 1209 if (*es != execsw_arg) 1210 *xs++ = *es; 1211 *xs = NULL; 1212 if (execsw) 1213 free(execsw, M_TEMP); 1214 execsw = newexecsw; 1215 return (0); 1216 } 1217