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/resourcevar.h> 55 #include <sys/sf_buf.h> 56 #include <sys/syscallsubr.h> 57 #include <sys/sysent.h> 58 #include <sys/shm.h> 59 #include <sys/sysctl.h> 60 #include <sys/vnode.h> 61 #ifdef KTRACE 62 #include <sys/ktrace.h> 63 #endif 64 65 #include <vm/vm.h> 66 #include <vm/vm_param.h> 67 #include <vm/pmap.h> 68 #include <vm/vm_page.h> 69 #include <vm/vm_map.h> 70 #include <vm/vm_kern.h> 71 #include <vm/vm_extern.h> 72 #include <vm/vm_object.h> 73 #include <vm/vm_pager.h> 74 75 #include <machine/reg.h> 76 77 MALLOC_DEFINE(M_PARGS, "proc-args", "Process arguments"); 78 79 static int sysctl_kern_ps_strings(SYSCTL_HANDLER_ARGS); 80 static int sysctl_kern_usrstack(SYSCTL_HANDLER_ARGS); 81 static int sysctl_kern_stackprot(SYSCTL_HANDLER_ARGS); 82 static int do_execve(struct thread *td, char *fname, char **argv, 83 char **envv, struct mac *mac_p); 84 85 /* XXX This should be vm_size_t. */ 86 SYSCTL_PROC(_kern, KERN_PS_STRINGS, ps_strings, CTLTYPE_ULONG|CTLFLAG_RD, 87 NULL, 0, sysctl_kern_ps_strings, "LU", ""); 88 89 /* XXX This should be vm_size_t. */ 90 SYSCTL_PROC(_kern, KERN_USRSTACK, usrstack, CTLTYPE_ULONG|CTLFLAG_RD, 91 NULL, 0, sysctl_kern_usrstack, "LU", ""); 92 93 SYSCTL_PROC(_kern, OID_AUTO, stackprot, CTLTYPE_INT|CTLFLAG_RD, 94 NULL, 0, sysctl_kern_stackprot, "I", ""); 95 96 u_long ps_arg_cache_limit = PAGE_SIZE / 16; 97 SYSCTL_ULONG(_kern, OID_AUTO, ps_arg_cache_limit, CTLFLAG_RW, 98 &ps_arg_cache_limit, 0, ""); 99 100 static int 101 sysctl_kern_ps_strings(SYSCTL_HANDLER_ARGS) 102 { 103 struct proc *p; 104 int error; 105 106 p = curproc; 107 #ifdef SCTL_MASK32 108 if (req->flags & SCTL_MASK32) { 109 unsigned int val; 110 val = (unsigned int)p->p_sysent->sv_psstrings; 111 error = SYSCTL_OUT(req, &val, sizeof(val)); 112 } else 113 #endif 114 error = SYSCTL_OUT(req, &p->p_sysent->sv_psstrings, 115 sizeof(p->p_sysent->sv_psstrings)); 116 return error; 117 } 118 119 static int 120 sysctl_kern_usrstack(SYSCTL_HANDLER_ARGS) 121 { 122 struct proc *p; 123 int error; 124 125 p = curproc; 126 #ifdef SCTL_MASK32 127 if (req->flags & SCTL_MASK32) { 128 unsigned int val; 129 val = (unsigned int)p->p_sysent->sv_usrstack; 130 error = SYSCTL_OUT(req, &val, sizeof(val)); 131 } else 132 #endif 133 error = SYSCTL_OUT(req, &p->p_sysent->sv_usrstack, 134 sizeof(p->p_sysent->sv_usrstack)); 135 return error; 136 } 137 138 static int 139 sysctl_kern_stackprot(SYSCTL_HANDLER_ARGS) 140 { 141 struct proc *p; 142 143 p = curproc; 144 return (SYSCTL_OUT(req, &p->p_sysent->sv_stackprot, 145 sizeof(p->p_sysent->sv_stackprot))); 146 } 147 148 /* 149 * Each of the items is a pointer to a `const struct execsw', hence the 150 * double pointer here. 151 */ 152 static const struct execsw **execsw; 153 154 #ifndef _SYS_SYSPROTO_H_ 155 struct execve_args { 156 char *fname; 157 char **argv; 158 char **envv; 159 }; 160 #endif 161 162 /* 163 * MPSAFE 164 */ 165 int 166 execve(td, uap) 167 struct thread *td; 168 struct execve_args /* { 169 char *fname; 170 char **argv; 171 char **envv; 172 } */ *uap; 173 { 174 175 return (kern_execve(td, uap->fname, uap->argv, uap->envv, NULL)); 176 } 177 178 #ifndef _SYS_SYSPROTO_H_ 179 struct __mac_execve_args { 180 char *fname; 181 char **argv; 182 char **envv; 183 struct mac *mac_p; 184 }; 185 #endif 186 187 /* 188 * MPSAFE 189 */ 190 int 191 __mac_execve(td, uap) 192 struct thread *td; 193 struct __mac_execve_args /* { 194 char *fname; 195 char **argv; 196 char **envv; 197 struct mac *mac_p; 198 } */ *uap; 199 { 200 201 #ifdef MAC 202 return (kern_execve(td, uap->fname, uap->argv, uap->envv, 203 uap->mac_p)); 204 #else 205 return (ENOSYS); 206 #endif 207 } 208 209 int 210 kern_execve(td, fname, argv, envv, mac_p) 211 struct thread *td; 212 char *fname; 213 char **argv; 214 char **envv; 215 struct mac *mac_p; 216 { 217 struct proc *p = td->td_proc; 218 int error; 219 220 if (p->p_flag & P_HADTHREADS) { 221 PROC_LOCK(p); 222 if (thread_single(SINGLE_BOUNDARY)) { 223 PROC_UNLOCK(p); 224 return (ERESTART); /* Try again later. */ 225 } 226 PROC_UNLOCK(p); 227 } 228 229 error = do_execve(td, fname, argv, envv, mac_p); 230 231 if (p->p_flag & P_HADTHREADS) { 232 PROC_LOCK(p); 233 /* 234 * If success, we upgrade to SINGLE_EXIT state to 235 * force other threads to suicide. 236 */ 237 if (error == 0) 238 thread_single(SINGLE_EXIT); 239 else 240 thread_single_end(); 241 PROC_UNLOCK(p); 242 } 243 244 return (error); 245 } 246 247 /* 248 * In-kernel implementation of execve(). All arguments are assumed to be 249 * userspace pointers from the passed thread. 250 * 251 * MPSAFE 252 */ 253 static int 254 do_execve(td, fname, argv, envv, mac_p) 255 struct thread *td; 256 char *fname; 257 char **argv; 258 char **envv; 259 struct mac *mac_p; 260 { 261 struct proc *p = td->td_proc; 262 struct nameidata nd, *ndp; 263 struct ucred *newcred = NULL, *oldcred; 264 struct uidinfo *euip; 265 register_t *stack_base; 266 int error, len, i; 267 struct image_params image_params, *imgp; 268 struct vattr attr; 269 int (*img_first)(struct image_params *); 270 struct pargs *oldargs = NULL, *newargs = NULL; 271 struct sigacts *oldsigacts, *newsigacts; 272 #ifdef KTRACE 273 struct vnode *tracevp = NULL; 274 struct ucred *tracecred = NULL; 275 #endif 276 struct vnode *textvp = NULL; 277 int credential_changing; 278 int textset; 279 #ifdef MAC 280 struct label *interplabel = NULL; 281 int will_transition; 282 #endif 283 284 imgp = &image_params; 285 286 /* 287 * Lock the process and set the P_INEXEC flag to indicate that 288 * it should be left alone until we're done here. This is 289 * necessary to avoid race conditions - e.g. in ptrace() - 290 * that might allow a local user to illicitly obtain elevated 291 * privileges. 292 */ 293 PROC_LOCK(p); 294 KASSERT((p->p_flag & P_INEXEC) == 0, 295 ("%s(): process already has P_INEXEC flag", __func__)); 296 p->p_flag |= P_INEXEC; 297 PROC_UNLOCK(p); 298 299 /* 300 * Initialize part of the common data 301 */ 302 imgp->proc = p; 303 imgp->userspace_argv = argv; 304 imgp->userspace_envv = envv; 305 imgp->execlabel = NULL; 306 imgp->attr = &attr; 307 imgp->argc = imgp->envc = 0; 308 imgp->argv0 = NULL; 309 imgp->entry_addr = 0; 310 imgp->vmspace_destroyed = 0; 311 imgp->interpreted = 0; 312 imgp->interpreter_name[0] = '\0'; 313 imgp->auxargs = NULL; 314 imgp->vp = NULL; 315 imgp->object = NULL; 316 imgp->firstpage = NULL; 317 imgp->ps_strings = 0; 318 imgp->auxarg_size = 0; 319 320 #ifdef MAC 321 error = mac_execve_enter(imgp, mac_p); 322 if (error) { 323 mtx_lock(&Giant); 324 goto exec_fail; 325 } 326 #endif 327 328 /* 329 * Allocate temporary demand zeroed space for argument and 330 * environment strings 331 */ 332 imgp->stringbase = (char *)kmem_alloc_wait(exec_map, ARG_MAX); 333 if (imgp->stringbase == NULL) { 334 error = ENOMEM; 335 mtx_lock(&Giant); 336 goto exec_fail; 337 } 338 imgp->stringp = imgp->stringbase; 339 imgp->stringspace = ARG_MAX; 340 imgp->image_header = NULL; 341 342 /* 343 * Translate the file name. namei() returns a vnode pointer 344 * in ni_vp amoung other things. 345 */ 346 ndp = &nd; 347 NDINIT(ndp, LOOKUP, LOCKLEAF | FOLLOW | SAVENAME, 348 UIO_USERSPACE, fname, td); 349 350 mtx_lock(&Giant); 351 interpret: 352 353 error = namei(ndp); 354 if (error) { 355 kmem_free_wakeup(exec_map, (vm_offset_t)imgp->stringbase, 356 ARG_MAX); 357 goto exec_fail; 358 } 359 360 imgp->vp = ndp->ni_vp; 361 imgp->fname = fname; 362 363 /* 364 * Check file permissions (also 'opens' file) 365 */ 366 error = exec_check_permissions(imgp); 367 if (error) 368 goto exec_fail_dealloc; 369 370 if (VOP_GETVOBJECT(imgp->vp, &imgp->object) == 0) 371 vm_object_reference(imgp->object); 372 373 /* 374 * Set VV_TEXT now so no one can write to the executable while we're 375 * activating it. 376 * 377 * Remember if this was set before and unset it in case this is not 378 * actually an executable image. 379 */ 380 textset = imgp->vp->v_vflag & VV_TEXT; 381 imgp->vp->v_vflag |= VV_TEXT; 382 383 error = exec_map_first_page(imgp); 384 if (error) 385 goto exec_fail_dealloc; 386 387 /* 388 * If the current process has a special image activator it 389 * wants to try first, call it. For example, emulating shell 390 * scripts differently. 391 */ 392 error = -1; 393 if ((img_first = imgp->proc->p_sysent->sv_imgact_try) != NULL) 394 error = img_first(imgp); 395 396 /* 397 * Loop through the list of image activators, calling each one. 398 * An activator returns -1 if there is no match, 0 on success, 399 * and an error otherwise. 400 */ 401 for (i = 0; error == -1 && execsw[i]; ++i) { 402 if (execsw[i]->ex_imgact == NULL || 403 execsw[i]->ex_imgact == img_first) { 404 continue; 405 } 406 error = (*execsw[i]->ex_imgact)(imgp); 407 } 408 409 if (error) { 410 if (error == -1) { 411 if (textset == 0) 412 imgp->vp->v_vflag &= ~VV_TEXT; 413 error = ENOEXEC; 414 } 415 goto exec_fail_dealloc; 416 } 417 418 /* 419 * Special interpreter operation, cleanup and loop up to try to 420 * activate the interpreter. 421 */ 422 if (imgp->interpreted) { 423 exec_unmap_first_page(imgp); 424 /* 425 * VV_TEXT needs to be unset for scripts. There is a short 426 * period before we determine that something is a script where 427 * VV_TEXT will be set. The vnode lock is held over this 428 * entire period so nothing should illegitimately be blocked. 429 */ 430 imgp->vp->v_vflag &= ~VV_TEXT; 431 /* free name buffer and old vnode */ 432 NDFREE(ndp, NDF_ONLY_PNBUF); 433 #ifdef MAC 434 interplabel = mac_vnode_label_alloc(); 435 mac_copy_vnode_label(ndp->ni_vp->v_label, interplabel); 436 #endif 437 vput(ndp->ni_vp); 438 vm_object_deallocate(imgp->object); 439 imgp->object = NULL; 440 /* set new name to that of the interpreter */ 441 NDINIT(ndp, LOOKUP, LOCKLEAF | FOLLOW | SAVENAME, 442 UIO_SYSSPACE, imgp->interpreter_name, td); 443 goto interpret; 444 } 445 446 /* 447 * Copy out strings (args and env) and initialize stack base 448 */ 449 if (p->p_sysent->sv_copyout_strings) 450 stack_base = (*p->p_sysent->sv_copyout_strings)(imgp); 451 else 452 stack_base = exec_copyout_strings(imgp); 453 454 /* 455 * If custom stack fixup routine present for this process 456 * let it do the stack setup. 457 * Else stuff argument count as first item on stack 458 */ 459 if (p->p_sysent->sv_fixup != NULL) 460 (*p->p_sysent->sv_fixup)(&stack_base, imgp); 461 else 462 suword(--stack_base, imgp->argc); 463 464 /* 465 * For security and other reasons, the file descriptor table cannot 466 * be shared after an exec. 467 */ 468 FILEDESC_LOCK_FAST(p->p_fd); 469 if (p->p_fd->fd_refcnt > 1) { 470 struct filedesc *tmp; 471 472 FILEDESC_UNLOCK_FAST(p->p_fd); 473 tmp = fdcopy(p->p_fd); 474 fdfree(td); 475 p->p_fd = tmp; 476 } else 477 FILEDESC_UNLOCK_FAST(p->p_fd); 478 479 /* 480 * Malloc things before we need locks. 481 */ 482 newcred = crget(); 483 euip = uifind(attr.va_uid); 484 i = imgp->endargs - imgp->stringbase; 485 if (ps_arg_cache_limit >= i + sizeof(struct pargs)) 486 newargs = pargs_alloc(i); 487 488 /* close files on exec */ 489 fdcloseexec(td); 490 491 /* Get a reference to the vnode prior to locking the proc */ 492 VREF(ndp->ni_vp); 493 494 /* 495 * For security and other reasons, signal handlers cannot 496 * be shared after an exec. The new process gets a copy of the old 497 * handlers. In execsigs(), the new process will have its signals 498 * reset. 499 */ 500 PROC_LOCK(p); 501 if (sigacts_shared(p->p_sigacts)) { 502 oldsigacts = p->p_sigacts; 503 PROC_UNLOCK(p); 504 newsigacts = sigacts_alloc(); 505 sigacts_copy(newsigacts, oldsigacts); 506 PROC_LOCK(p); 507 p->p_sigacts = newsigacts; 508 } else 509 oldsigacts = NULL; 510 511 /* Stop profiling */ 512 stopprofclock(p); 513 514 /* reset caught signals */ 515 execsigs(p); 516 517 /* name this process - nameiexec(p, ndp) */ 518 len = min(ndp->ni_cnd.cn_namelen,MAXCOMLEN); 519 bcopy(ndp->ni_cnd.cn_nameptr, p->p_comm, len); 520 p->p_comm[len] = 0; 521 522 /* 523 * mark as execed, wakeup the process that vforked (if any) and tell 524 * it that it now has its own resources back 525 */ 526 p->p_flag |= P_EXEC; 527 if (p->p_pptr && (p->p_flag & P_PPWAIT)) { 528 p->p_flag &= ~P_PPWAIT; 529 wakeup(p->p_pptr); 530 } 531 532 /* 533 * Implement image setuid/setgid. 534 * 535 * Don't honor setuid/setgid if the filesystem prohibits it or if 536 * the process is being traced. 537 * 538 * XXXMAC: For the time being, use NOSUID to also prohibit 539 * transitions on the file system. 540 */ 541 oldcred = p->p_ucred; 542 credential_changing = 0; 543 credential_changing |= (attr.va_mode & VSUID) && oldcred->cr_uid != 544 attr.va_uid; 545 credential_changing |= (attr.va_mode & VSGID) && oldcred->cr_gid != 546 attr.va_gid; 547 #ifdef MAC 548 will_transition = mac_execve_will_transition(oldcred, imgp->vp, 549 interplabel, imgp); 550 credential_changing |= will_transition; 551 #endif 552 553 if (credential_changing && 554 (imgp->vp->v_mount->mnt_flag & MNT_NOSUID) == 0 && 555 (p->p_flag & P_TRACED) == 0) { 556 /* 557 * Turn off syscall tracing for set-id programs, except for 558 * root. Record any set-id flags first to make sure that 559 * we do not regain any tracing during a possible block. 560 */ 561 setsugid(p); 562 #ifdef KTRACE 563 if (p->p_tracevp != NULL && suser_cred(oldcred, SUSER_ALLOWJAIL)) { 564 mtx_lock(&ktrace_mtx); 565 p->p_traceflag = 0; 566 tracevp = p->p_tracevp; 567 p->p_tracevp = NULL; 568 tracecred = p->p_tracecred; 569 p->p_tracecred = NULL; 570 mtx_unlock(&ktrace_mtx); 571 } 572 #endif 573 /* 574 * Close any file descriptors 0..2 that reference procfs, 575 * then make sure file descriptors 0..2 are in use. 576 * 577 * setugidsafety() may call closef() and then pfind() 578 * which may grab the process lock. 579 * fdcheckstd() may call falloc() which may block to 580 * allocate memory, so temporarily drop the process lock. 581 */ 582 PROC_UNLOCK(p); 583 setugidsafety(td); 584 error = fdcheckstd(td); 585 if (error != 0) 586 goto done1; 587 PROC_LOCK(p); 588 /* 589 * Set the new credentials. 590 */ 591 crcopy(newcred, oldcred); 592 if (attr.va_mode & VSUID) 593 change_euid(newcred, euip); 594 if (attr.va_mode & VSGID) 595 change_egid(newcred, attr.va_gid); 596 #ifdef MAC 597 if (will_transition) { 598 mac_execve_transition(oldcred, newcred, imgp->vp, 599 interplabel, imgp); 600 } 601 #endif 602 /* 603 * Implement correct POSIX saved-id behavior. 604 * 605 * XXXMAC: Note that the current logic will save the 606 * uid and gid if a MAC domain transition occurs, even 607 * though maybe it shouldn't. 608 */ 609 change_svuid(newcred, newcred->cr_uid); 610 change_svgid(newcred, newcred->cr_gid); 611 p->p_ucred = newcred; 612 newcred = NULL; 613 } else { 614 if (oldcred->cr_uid == oldcred->cr_ruid && 615 oldcred->cr_gid == oldcred->cr_rgid) 616 p->p_flag &= ~P_SUGID; 617 /* 618 * Implement correct POSIX saved-id behavior. 619 * 620 * XXX: It's not clear that the existing behavior is 621 * POSIX-compliant. A number of sources indicate that the 622 * saved uid/gid should only be updated if the new ruid is 623 * not equal to the old ruid, or the new euid is not equal 624 * to the old euid and the new euid is not equal to the old 625 * ruid. The FreeBSD code always updates the saved uid/gid. 626 * Also, this code uses the new (replaced) euid and egid as 627 * the source, which may or may not be the right ones to use. 628 */ 629 if (oldcred->cr_svuid != oldcred->cr_uid || 630 oldcred->cr_svgid != oldcred->cr_gid) { 631 crcopy(newcred, oldcred); 632 change_svuid(newcred, newcred->cr_uid); 633 change_svgid(newcred, newcred->cr_gid); 634 p->p_ucred = newcred; 635 newcred = NULL; 636 } 637 } 638 639 /* 640 * Store the vp for use in procfs. This vnode was referenced prior 641 * to locking the proc lock. 642 */ 643 textvp = p->p_textvp; 644 p->p_textvp = ndp->ni_vp; 645 646 /* 647 * Notify others that we exec'd, and clear the P_INEXEC flag 648 * as we're now a bona fide freshly-execed process. 649 */ 650 KNOTE_LOCKED(&p->p_klist, NOTE_EXEC); 651 p->p_flag &= ~P_INEXEC; 652 653 /* 654 * If tracing the process, trap to debugger so breakpoints 655 * can be set before the program executes. 656 * Use tdsignal to deliver signal to current thread, use 657 * psignal may cause the signal to be delivered to wrong thread 658 * because that thread will exit, remember we are going to enter 659 * single thread mode. 660 */ 661 if (p->p_flag & P_TRACED) 662 tdsignal(td, SIGTRAP, SIGTARGET_TD); 663 664 /* clear "fork but no exec" flag, as we _are_ execing */ 665 p->p_acflag &= ~AFORK; 666 667 /* Free any previous argument cache */ 668 oldargs = p->p_args; 669 p->p_args = NULL; 670 671 /* Cache arguments if they fit inside our allowance */ 672 if (ps_arg_cache_limit >= i + sizeof(struct pargs)) { 673 bcopy(imgp->stringbase, newargs->ar_args, i); 674 p->p_args = newargs; 675 newargs = NULL; 676 } 677 PROC_UNLOCK(p); 678 679 /* Set values passed into the program in registers. */ 680 if (p->p_sysent->sv_setregs) 681 (*p->p_sysent->sv_setregs)(td, imgp->entry_addr, 682 (u_long)(uintptr_t)stack_base, imgp->ps_strings); 683 else 684 exec_setregs(td, imgp->entry_addr, 685 (u_long)(uintptr_t)stack_base, imgp->ps_strings); 686 687 done1: 688 /* 689 * Free any resources malloc'd earlier that we didn't use. 690 */ 691 uifree(euip); 692 if (newcred == NULL) 693 crfree(oldcred); 694 else 695 crfree(newcred); 696 /* 697 * Handle deferred decrement of ref counts. 698 */ 699 if (textvp != NULL) 700 vrele(textvp); 701 if (ndp->ni_vp && error != 0) 702 vrele(ndp->ni_vp); 703 #ifdef KTRACE 704 if (tracevp != NULL) 705 vrele(tracevp); 706 if (tracecred != NULL) 707 crfree(tracecred); 708 #endif 709 if (oldargs != NULL) 710 pargs_drop(oldargs); 711 if (newargs != NULL) 712 pargs_drop(newargs); 713 if (oldsigacts != NULL) 714 sigacts_free(oldsigacts); 715 716 exec_fail_dealloc: 717 718 /* 719 * free various allocated resources 720 */ 721 if (imgp->firstpage != NULL) 722 exec_unmap_first_page(imgp); 723 724 if (imgp->vp != NULL) { 725 NDFREE(ndp, NDF_ONLY_PNBUF); 726 vput(imgp->vp); 727 } 728 729 if (imgp->stringbase != NULL) 730 kmem_free_wakeup(exec_map, (vm_offset_t)imgp->stringbase, 731 ARG_MAX); 732 733 if (imgp->object != NULL) 734 vm_object_deallocate(imgp->object); 735 736 if (error == 0) { 737 /* 738 * Stop the process here if its stop event mask has 739 * the S_EXEC bit set. 740 */ 741 STOPEVENT(p, S_EXEC, 0); 742 goto done2; 743 } 744 745 exec_fail: 746 /* we're done here, clear P_INEXEC */ 747 PROC_LOCK(p); 748 p->p_flag &= ~P_INEXEC; 749 PROC_UNLOCK(p); 750 751 if (imgp->vmspace_destroyed) { 752 /* sorry, no more process anymore. exit gracefully */ 753 #ifdef MAC 754 mac_execve_exit(imgp); 755 if (interplabel != NULL) 756 mac_vnode_label_free(interplabel); 757 #endif 758 mtx_unlock(&Giant); 759 exit1(td, W_EXITCODE(0, SIGABRT)); 760 /* NOT REACHED */ 761 error = 0; 762 } 763 done2: 764 #ifdef MAC 765 mac_execve_exit(imgp); 766 if (interplabel != NULL) 767 mac_vnode_label_free(interplabel); 768 #endif 769 mtx_unlock(&Giant); 770 return (error); 771 } 772 773 int 774 exec_map_first_page(imgp) 775 struct image_params *imgp; 776 { 777 int rv, i; 778 int initial_pagein; 779 vm_page_t ma[VM_INITIAL_PAGEIN]; 780 vm_object_t object; 781 782 GIANT_REQUIRED; 783 784 if (imgp->firstpage != NULL) 785 exec_unmap_first_page(imgp); 786 787 VOP_GETVOBJECT(imgp->vp, &object); 788 VM_OBJECT_LOCK(object); 789 ma[0] = vm_page_grab(object, 0, VM_ALLOC_NORMAL | VM_ALLOC_RETRY); 790 if ((ma[0]->valid & VM_PAGE_BITS_ALL) != VM_PAGE_BITS_ALL) { 791 initial_pagein = VM_INITIAL_PAGEIN; 792 if (initial_pagein > object->size) 793 initial_pagein = object->size; 794 for (i = 1; i < initial_pagein; i++) { 795 if ((ma[i] = vm_page_lookup(object, i)) != NULL) { 796 if (ma[i]->valid) 797 break; 798 vm_page_lock_queues(); 799 if ((ma[i]->flags & PG_BUSY) || ma[i]->busy) { 800 vm_page_unlock_queues(); 801 break; 802 } 803 vm_page_busy(ma[i]); 804 vm_page_unlock_queues(); 805 } else { 806 ma[i] = vm_page_alloc(object, i, 807 VM_ALLOC_NORMAL); 808 if (ma[i] == NULL) 809 break; 810 } 811 } 812 initial_pagein = i; 813 rv = vm_pager_get_pages(object, ma, initial_pagein, 0); 814 ma[0] = vm_page_lookup(object, 0); 815 if ((rv != VM_PAGER_OK) || (ma[0] == NULL) || 816 (ma[0]->valid == 0)) { 817 if (ma[0]) { 818 vm_page_lock_queues(); 819 pmap_remove_all(ma[0]); 820 vm_page_free(ma[0]); 821 vm_page_unlock_queues(); 822 } 823 VM_OBJECT_UNLOCK(object); 824 return (EIO); 825 } 826 } 827 vm_page_lock_queues(); 828 vm_page_hold(ma[0]); 829 vm_page_wakeup(ma[0]); 830 vm_page_unlock_queues(); 831 VM_OBJECT_UNLOCK(object); 832 833 imgp->firstpage = sf_buf_alloc(ma[0], 0); 834 imgp->image_header = (char *)sf_buf_kva(imgp->firstpage); 835 836 return (0); 837 } 838 839 void 840 exec_unmap_first_page(imgp) 841 struct image_params *imgp; 842 { 843 vm_page_t m; 844 845 if (imgp->firstpage != NULL) { 846 m = sf_buf_page(imgp->firstpage); 847 sf_buf_free(imgp->firstpage); 848 imgp->firstpage = NULL; 849 vm_page_lock_queues(); 850 vm_page_unhold(m); 851 vm_page_unlock_queues(); 852 } 853 } 854 855 /* 856 * Destroy old address space, and allocate a new stack 857 * The new stack is only SGROWSIZ large because it is grown 858 * automatically in trap.c. 859 */ 860 int 861 exec_new_vmspace(imgp, sv) 862 struct image_params *imgp; 863 struct sysentvec *sv; 864 { 865 int error; 866 struct proc *p = imgp->proc; 867 struct vmspace *vmspace = p->p_vmspace; 868 vm_offset_t stack_addr; 869 vm_map_t map; 870 871 GIANT_REQUIRED; 872 873 imgp->vmspace_destroyed = 1; 874 875 /* Called with Giant held, do not depend on it! */ 876 EVENTHANDLER_INVOKE(process_exec, p); 877 878 /* 879 * Here is as good a place as any to do any resource limit cleanups. 880 * This is needed if a 64 bit binary exec's a 32 bit binary - the 881 * data size limit may need to be changed to a value that makes 882 * sense for the 32 bit binary. 883 */ 884 if (sv->sv_fixlimits != NULL) 885 sv->sv_fixlimits(imgp); 886 887 /* 888 * Blow away entire process VM, if address space not shared, 889 * otherwise, create a new VM space so that other threads are 890 * not disrupted 891 */ 892 map = &vmspace->vm_map; 893 if (vmspace->vm_refcnt == 1 && vm_map_min(map) == sv->sv_minuser && 894 vm_map_max(map) == sv->sv_maxuser) { 895 shmexit(vmspace); 896 pmap_remove_pages(vmspace_pmap(vmspace), vm_map_min(map), 897 vm_map_max(map)); 898 vm_map_remove(map, vm_map_min(map), vm_map_max(map)); 899 } else { 900 vmspace_exec(p, sv->sv_minuser, sv->sv_maxuser); 901 vmspace = p->p_vmspace; 902 map = &vmspace->vm_map; 903 } 904 905 /* Allocate a new stack */ 906 stack_addr = sv->sv_usrstack - maxssiz; 907 error = vm_map_stack(map, stack_addr, (vm_size_t)maxssiz, 908 sv->sv_stackprot, VM_PROT_ALL, MAP_STACK_GROWS_DOWN); 909 if (error) 910 return (error); 911 912 #ifdef __ia64__ 913 /* Allocate a new register stack */ 914 stack_addr = IA64_BACKINGSTORE; 915 error = vm_map_stack(map, stack_addr, (vm_size_t)maxssiz, 916 sv->sv_stackprot, VM_PROT_ALL, MAP_STACK_GROWS_UP); 917 if (error) 918 return (error); 919 #endif 920 921 /* vm_ssize and vm_maxsaddr are somewhat antiquated concepts in the 922 * VM_STACK case, but they are still used to monitor the size of the 923 * process stack so we can check the stack rlimit. 924 */ 925 vmspace->vm_ssize = sgrowsiz >> PAGE_SHIFT; 926 vmspace->vm_maxsaddr = (char *)sv->sv_usrstack - maxssiz; 927 928 return (0); 929 } 930 931 /* 932 * Copy out argument and environment strings from the old process 933 * address space into the temporary string buffer. 934 */ 935 int 936 exec_extract_strings(imgp) 937 struct image_params *imgp; 938 { 939 char **argv, **envv; 940 char *argp, *envp; 941 int error; 942 size_t length; 943 944 /* 945 * extract arguments first 946 */ 947 948 argv = imgp->userspace_argv; 949 950 if (argv) { 951 argp = (caddr_t)(intptr_t)fuword(argv); 952 if (argp == (caddr_t)-1) 953 return (EFAULT); 954 if (argp) 955 argv++; 956 if (imgp->argv0) 957 argp = imgp->argv0; 958 if (argp) { 959 do { 960 if (argp == (caddr_t)-1) 961 return (EFAULT); 962 if ((error = copyinstr(argp, imgp->stringp, 963 imgp->stringspace, &length))) { 964 if (error == ENAMETOOLONG) 965 return (E2BIG); 966 return (error); 967 } 968 imgp->stringspace -= length; 969 imgp->stringp += length; 970 imgp->argc++; 971 } while ((argp = (caddr_t)(intptr_t)fuword(argv++))); 972 } 973 } else 974 return (EFAULT); 975 976 imgp->endargs = imgp->stringp; 977 978 /* 979 * extract environment strings 980 */ 981 982 envv = imgp->userspace_envv; 983 984 if (envv) { 985 while ((envp = (caddr_t)(intptr_t)fuword(envv++))) { 986 if (envp == (caddr_t)-1) 987 return (EFAULT); 988 if ((error = copyinstr(envp, imgp->stringp, 989 imgp->stringspace, &length))) { 990 if (error == ENAMETOOLONG) 991 return (E2BIG); 992 return (error); 993 } 994 imgp->stringspace -= length; 995 imgp->stringp += length; 996 imgp->envc++; 997 } 998 } 999 1000 return (0); 1001 } 1002 1003 /* 1004 * Copy strings out to the new process address space, constructing 1005 * new arg and env vector tables. Return a pointer to the base 1006 * so that it can be used as the initial stack pointer. 1007 */ 1008 register_t * 1009 exec_copyout_strings(imgp) 1010 struct image_params *imgp; 1011 { 1012 int argc, envc; 1013 char **vectp; 1014 char *stringp, *destp; 1015 register_t *stack_base; 1016 struct ps_strings *arginfo; 1017 struct proc *p; 1018 int szsigcode; 1019 1020 /* 1021 * Calculate string base and vector table pointers. 1022 * Also deal with signal trampoline code for this exec type. 1023 */ 1024 p = imgp->proc; 1025 szsigcode = 0; 1026 arginfo = (struct ps_strings *)p->p_sysent->sv_psstrings; 1027 if (p->p_sysent->sv_szsigcode != NULL) 1028 szsigcode = *(p->p_sysent->sv_szsigcode); 1029 destp = (caddr_t)arginfo - szsigcode - SPARE_USRSPACE - 1030 roundup((ARG_MAX - imgp->stringspace), sizeof(char *)); 1031 1032 /* 1033 * install sigcode 1034 */ 1035 if (szsigcode) 1036 copyout(p->p_sysent->sv_sigcode, ((caddr_t)arginfo - 1037 szsigcode), szsigcode); 1038 1039 /* 1040 * If we have a valid auxargs ptr, prepare some room 1041 * on the stack. 1042 */ 1043 if (imgp->auxargs) { 1044 /* 1045 * 'AT_COUNT*2' is size for the ELF Auxargs data. This is for 1046 * lower compatibility. 1047 */ 1048 imgp->auxarg_size = (imgp->auxarg_size) ? imgp->auxarg_size : 1049 (AT_COUNT * 2); 1050 /* 1051 * The '+ 2' is for the null pointers at the end of each of 1052 * the arg and env vector sets,and imgp->auxarg_size is room 1053 * for argument of Runtime loader. 1054 */ 1055 vectp = (char **)(destp - (imgp->argc + imgp->envc + 2 + 1056 imgp->auxarg_size) * sizeof(char *)); 1057 1058 } else 1059 /* 1060 * The '+ 2' is for the null pointers at the end of each of 1061 * the arg and env vector sets 1062 */ 1063 vectp = (char **)(destp - (imgp->argc + imgp->envc + 2) * 1064 sizeof(char *)); 1065 1066 /* 1067 * vectp also becomes our initial stack base 1068 */ 1069 stack_base = (register_t *)vectp; 1070 1071 stringp = imgp->stringbase; 1072 argc = imgp->argc; 1073 envc = imgp->envc; 1074 1075 /* 1076 * Copy out strings - arguments and environment. 1077 */ 1078 copyout(stringp, destp, ARG_MAX - imgp->stringspace); 1079 1080 /* 1081 * Fill in "ps_strings" struct for ps, w, etc. 1082 */ 1083 suword(&arginfo->ps_argvstr, (long)(intptr_t)vectp); 1084 suword(&arginfo->ps_nargvstr, argc); 1085 1086 /* 1087 * Fill in argument portion of vector table. 1088 */ 1089 for (; argc > 0; --argc) { 1090 suword(vectp++, (long)(intptr_t)destp); 1091 while (*stringp++ != 0) 1092 destp++; 1093 destp++; 1094 } 1095 1096 /* a null vector table pointer separates the argp's from the envp's */ 1097 suword(vectp++, 0); 1098 1099 suword(&arginfo->ps_envstr, (long)(intptr_t)vectp); 1100 suword(&arginfo->ps_nenvstr, envc); 1101 1102 /* 1103 * Fill in environment portion of vector table. 1104 */ 1105 for (; envc > 0; --envc) { 1106 suword(vectp++, (long)(intptr_t)destp); 1107 while (*stringp++ != 0) 1108 destp++; 1109 destp++; 1110 } 1111 1112 /* end of vector table is a null pointer */ 1113 suword(vectp, 0); 1114 1115 return (stack_base); 1116 } 1117 1118 /* 1119 * Check permissions of file to execute. 1120 * Called with imgp->vp locked. 1121 * Return 0 for success or error code on failure. 1122 */ 1123 int 1124 exec_check_permissions(imgp) 1125 struct image_params *imgp; 1126 { 1127 struct vnode *vp = imgp->vp; 1128 struct vattr *attr = imgp->attr; 1129 struct thread *td; 1130 int error; 1131 1132 td = curthread; /* XXXKSE */ 1133 1134 /* Get file attributes */ 1135 error = VOP_GETATTR(vp, attr, td->td_ucred, td); 1136 if (error) 1137 return (error); 1138 1139 #ifdef MAC 1140 error = mac_check_vnode_exec(td->td_ucred, imgp->vp, imgp); 1141 if (error) 1142 return (error); 1143 #endif 1144 1145 /* 1146 * 1) Check if file execution is disabled for the filesystem that this 1147 * file resides on. 1148 * 2) Insure that at least one execute bit is on - otherwise root 1149 * will always succeed, and we don't want to happen unless the 1150 * file really is executable. 1151 * 3) Insure that the file is a regular file. 1152 */ 1153 if ((vp->v_mount->mnt_flag & MNT_NOEXEC) || 1154 ((attr->va_mode & 0111) == 0) || 1155 (attr->va_type != VREG)) 1156 return (EACCES); 1157 1158 /* 1159 * Zero length files can't be exec'd 1160 */ 1161 if (attr->va_size == 0) 1162 return (ENOEXEC); 1163 1164 /* 1165 * Check for execute permission to file based on current credentials. 1166 */ 1167 error = VOP_ACCESS(vp, VEXEC, td->td_ucred, td); 1168 if (error) 1169 return (error); 1170 1171 /* 1172 * Check number of open-for-writes on the file and deny execution 1173 * if there are any. 1174 */ 1175 if (vp->v_writecount) 1176 return (ETXTBSY); 1177 1178 /* 1179 * Call filesystem specific open routine (which does nothing in the 1180 * general case). 1181 */ 1182 error = VOP_OPEN(vp, FREAD, td->td_ucred, td, -1); 1183 return (error); 1184 } 1185 1186 /* 1187 * Exec handler registration 1188 */ 1189 int 1190 exec_register(execsw_arg) 1191 const struct execsw *execsw_arg; 1192 { 1193 const struct execsw **es, **xs, **newexecsw; 1194 int count = 2; /* New slot and trailing NULL */ 1195 1196 if (execsw) 1197 for (es = execsw; *es; es++) 1198 count++; 1199 newexecsw = malloc(count * sizeof(*es), M_TEMP, M_WAITOK); 1200 if (newexecsw == NULL) 1201 return (ENOMEM); 1202 xs = newexecsw; 1203 if (execsw) 1204 for (es = execsw; *es; es++) 1205 *xs++ = *es; 1206 *xs++ = execsw_arg; 1207 *xs = NULL; 1208 if (execsw) 1209 free(execsw, M_TEMP); 1210 execsw = newexecsw; 1211 return (0); 1212 } 1213 1214 int 1215 exec_unregister(execsw_arg) 1216 const struct execsw *execsw_arg; 1217 { 1218 const struct execsw **es, **xs, **newexecsw; 1219 int count = 1; 1220 1221 if (execsw == NULL) 1222 panic("unregister with no handlers left?\n"); 1223 1224 for (es = execsw; *es; es++) { 1225 if (*es == execsw_arg) 1226 break; 1227 } 1228 if (*es == NULL) 1229 return (ENOENT); 1230 for (es = execsw; *es; es++) 1231 if (*es != execsw_arg) 1232 count++; 1233 newexecsw = malloc(count * sizeof(*es), M_TEMP, M_WAITOK); 1234 if (newexecsw == NULL) 1235 return (ENOMEM); 1236 xs = newexecsw; 1237 for (es = execsw; *es; es++) 1238 if (*es != execsw_arg) 1239 *xs++ = *es; 1240 *xs = NULL; 1241 if (execsw) 1242 free(execsw, M_TEMP); 1243 execsw = newexecsw; 1244 return (0); 1245 } 1246