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