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, struct image_args *args, 83 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 int error; 175 struct image_args args; 176 177 error = exec_copyin_args(&args, uap->fname, UIO_USERSPACE, 178 uap->argv, uap->envv); 179 180 if (error == 0) 181 error = kern_execve(td, &args, NULL); 182 183 exec_free_args(&args); 184 185 return (error); 186 } 187 188 #ifndef _SYS_SYSPROTO_H_ 189 struct __mac_execve_args { 190 char *fname; 191 char **argv; 192 char **envv; 193 struct mac *mac_p; 194 }; 195 #endif 196 197 /* 198 * MPSAFE 199 */ 200 int 201 __mac_execve(td, uap) 202 struct thread *td; 203 struct __mac_execve_args /* { 204 char *fname; 205 char **argv; 206 char **envv; 207 struct mac *mac_p; 208 } */ *uap; 209 { 210 #ifdef MAC 211 int error; 212 struct image_args args; 213 214 error = exec_copyin_args(&args, uap->fname, UIO_USERSPACE, 215 uap->argv, uap->envv); 216 217 if (error == 0) 218 error = kern_execve(td, &args, uap->mac_p); 219 220 exec_free_args(&args); 221 222 return (error); 223 #else 224 return (ENOSYS); 225 #endif 226 } 227 228 int 229 kern_execve(td, args, mac_p) 230 struct thread *td; 231 struct image_args *args; 232 struct mac *mac_p; 233 { 234 struct proc *p = td->td_proc; 235 int error; 236 237 if (p->p_flag & P_HADTHREADS) { 238 PROC_LOCK(p); 239 if (thread_single(SINGLE_BOUNDARY)) { 240 PROC_UNLOCK(p); 241 return (ERESTART); /* Try again later. */ 242 } 243 PROC_UNLOCK(p); 244 } 245 246 error = do_execve(td, args, mac_p); 247 248 if (p->p_flag & P_HADTHREADS) { 249 PROC_LOCK(p); 250 /* 251 * If success, we upgrade to SINGLE_EXIT state to 252 * force other threads to suicide. 253 */ 254 if (error == 0) 255 thread_single(SINGLE_EXIT); 256 else 257 thread_single_end(); 258 PROC_UNLOCK(p); 259 } 260 261 return (error); 262 } 263 264 /* 265 * In-kernel implementation of execve(). All arguments are assumed to be 266 * userspace pointers from the passed thread. 267 * 268 * MPSAFE 269 */ 270 static int 271 do_execve(td, args, mac_p) 272 struct thread *td; 273 struct image_args *args; 274 struct mac *mac_p; 275 { 276 struct proc *p = td->td_proc; 277 struct nameidata nd, *ndp; 278 struct ucred *newcred = NULL, *oldcred; 279 struct uidinfo *euip; 280 register_t *stack_base; 281 int error, len, i; 282 struct image_params image_params, *imgp; 283 struct vattr attr; 284 int (*img_first)(struct image_params *); 285 struct pargs *oldargs = NULL, *newargs = NULL; 286 struct sigacts *oldsigacts, *newsigacts; 287 #ifdef KTRACE 288 struct vnode *tracevp = NULL; 289 struct ucred *tracecred = NULL; 290 #endif 291 struct vnode *textvp = NULL; 292 int credential_changing; 293 int textset; 294 #ifdef MAC 295 struct label *interplabel = NULL; 296 int will_transition; 297 #endif 298 299 imgp = &image_params; 300 301 /* 302 * Lock the process and set the P_INEXEC flag to indicate that 303 * it should be left alone until we're done here. This is 304 * necessary to avoid race conditions - e.g. in ptrace() - 305 * that might allow a local user to illicitly obtain elevated 306 * privileges. 307 */ 308 PROC_LOCK(p); 309 KASSERT((p->p_flag & P_INEXEC) == 0, 310 ("%s(): process already has P_INEXEC flag", __func__)); 311 p->p_flag |= P_INEXEC; 312 PROC_UNLOCK(p); 313 314 /* 315 * Initialize part of the common data 316 */ 317 imgp->proc = p; 318 imgp->execlabel = NULL; 319 imgp->attr = &attr; 320 imgp->entry_addr = 0; 321 imgp->vmspace_destroyed = 0; 322 imgp->interpreted = 0; 323 imgp->interpreter_name = args->buf + PATH_MAX + ARG_MAX; 324 imgp->auxargs = NULL; 325 imgp->vp = NULL; 326 imgp->object = NULL; 327 imgp->firstpage = NULL; 328 imgp->ps_strings = 0; 329 imgp->auxarg_size = 0; 330 imgp->args = args; 331 332 #ifdef MAC 333 error = mac_execve_enter(imgp, mac_p); 334 if (error) { 335 mtx_lock(&Giant); 336 goto exec_fail; 337 } 338 #endif 339 340 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_SYSSPACE, args->fname, td); 349 350 mtx_lock(&Giant); 351 interpret: 352 353 error = namei(ndp); 354 if (error) 355 goto exec_fail; 356 357 imgp->vp = ndp->ni_vp; 358 359 /* 360 * Check file permissions (also 'opens' file) 361 */ 362 error = exec_check_permissions(imgp); 363 if (error) 364 goto exec_fail_dealloc; 365 366 imgp->object = imgp->vp->v_object; 367 if (imgp->object != NULL) 368 vm_object_reference(imgp->object); 369 370 /* 371 * Set VV_TEXT now so no one can write to the executable while we're 372 * activating it. 373 * 374 * Remember if this was set before and unset it in case this is not 375 * actually an executable image. 376 */ 377 textset = imgp->vp->v_vflag & VV_TEXT; 378 imgp->vp->v_vflag |= VV_TEXT; 379 380 error = exec_map_first_page(imgp); 381 if (error) 382 goto exec_fail_dealloc; 383 384 /* 385 * If the current process has a special image activator it 386 * wants to try first, call it. For example, emulating shell 387 * scripts differently. 388 */ 389 error = -1; 390 if ((img_first = imgp->proc->p_sysent->sv_imgact_try) != NULL) 391 error = img_first(imgp); 392 393 /* 394 * Loop through the list of image activators, calling each one. 395 * An activator returns -1 if there is no match, 0 on success, 396 * and an error otherwise. 397 */ 398 for (i = 0; error == -1 && execsw[i]; ++i) { 399 if (execsw[i]->ex_imgact == NULL || 400 execsw[i]->ex_imgact == img_first) { 401 continue; 402 } 403 error = (*execsw[i]->ex_imgact)(imgp); 404 } 405 406 if (error) { 407 if (error == -1) { 408 if (textset == 0) 409 imgp->vp->v_vflag &= ~VV_TEXT; 410 error = ENOEXEC; 411 } 412 goto exec_fail_dealloc; 413 } 414 415 /* 416 * Special interpreter operation, cleanup and loop up to try to 417 * activate the interpreter. 418 */ 419 if (imgp->interpreted) { 420 exec_unmap_first_page(imgp); 421 /* 422 * VV_TEXT needs to be unset for scripts. There is a short 423 * period before we determine that something is a script where 424 * VV_TEXT will be set. The vnode lock is held over this 425 * entire period so nothing should illegitimately be blocked. 426 */ 427 imgp->vp->v_vflag &= ~VV_TEXT; 428 /* free name buffer and old vnode */ 429 NDFREE(ndp, NDF_ONLY_PNBUF); 430 #ifdef MAC 431 interplabel = mac_vnode_label_alloc(); 432 mac_copy_vnode_label(ndp->ni_vp->v_label, interplabel); 433 #endif 434 vput(ndp->ni_vp); 435 vm_object_deallocate(imgp->object); 436 imgp->object = NULL; 437 /* set new name to that of the interpreter */ 438 NDINIT(ndp, LOOKUP, LOCKLEAF | FOLLOW | SAVENAME, 439 UIO_SYSSPACE, imgp->interpreter_name, td); 440 goto interpret; 441 } 442 443 /* 444 * Copy out strings (args and env) and initialize stack base 445 */ 446 if (p->p_sysent->sv_copyout_strings) 447 stack_base = (*p->p_sysent->sv_copyout_strings)(imgp); 448 else 449 stack_base = exec_copyout_strings(imgp); 450 451 /* 452 * If custom stack fixup routine present for this process 453 * let it do the stack setup. 454 * Else stuff argument count as first item on stack 455 */ 456 if (p->p_sysent->sv_fixup != NULL) 457 (*p->p_sysent->sv_fixup)(&stack_base, imgp); 458 else 459 suword(--stack_base, imgp->args->argc); 460 461 /* 462 * For security and other reasons, the file descriptor table cannot 463 * be shared after an exec. 464 */ 465 fdunshare(p, td); 466 467 /* 468 * Malloc things before we need locks. 469 */ 470 newcred = crget(); 471 euip = uifind(attr.va_uid); 472 i = imgp->args->begin_envv - imgp->args->begin_argv; 473 if (ps_arg_cache_limit >= i + sizeof(struct pargs)) 474 newargs = pargs_alloc(i); 475 476 /* close files on exec */ 477 fdcloseexec(td); 478 479 /* Get a reference to the vnode prior to locking the proc */ 480 VREF(ndp->ni_vp); 481 482 /* 483 * For security and other reasons, signal handlers cannot 484 * be shared after an exec. The new process gets a copy of the old 485 * handlers. In execsigs(), the new process will have its signals 486 * reset. 487 */ 488 PROC_LOCK(p); 489 if (sigacts_shared(p->p_sigacts)) { 490 oldsigacts = p->p_sigacts; 491 PROC_UNLOCK(p); 492 newsigacts = sigacts_alloc(); 493 sigacts_copy(newsigacts, oldsigacts); 494 PROC_LOCK(p); 495 p->p_sigacts = newsigacts; 496 } else 497 oldsigacts = NULL; 498 499 /* Stop profiling */ 500 stopprofclock(p); 501 502 /* reset caught signals */ 503 execsigs(p); 504 505 /* name this process - nameiexec(p, ndp) */ 506 len = min(ndp->ni_cnd.cn_namelen,MAXCOMLEN); 507 bcopy(ndp->ni_cnd.cn_nameptr, p->p_comm, len); 508 p->p_comm[len] = 0; 509 510 /* 511 * mark as execed, wakeup the process that vforked (if any) and tell 512 * it that it now has its own resources back 513 */ 514 p->p_flag |= P_EXEC; 515 if (p->p_pptr && (p->p_flag & P_PPWAIT)) { 516 p->p_flag &= ~P_PPWAIT; 517 wakeup(p->p_pptr); 518 } 519 520 /* 521 * Implement image setuid/setgid. 522 * 523 * Don't honor setuid/setgid if the filesystem prohibits it or if 524 * the process is being traced. 525 * 526 * XXXMAC: For the time being, use NOSUID to also prohibit 527 * transitions on the file system. 528 */ 529 oldcred = p->p_ucred; 530 credential_changing = 0; 531 credential_changing |= (attr.va_mode & VSUID) && oldcred->cr_uid != 532 attr.va_uid; 533 credential_changing |= (attr.va_mode & VSGID) && oldcred->cr_gid != 534 attr.va_gid; 535 #ifdef MAC 536 will_transition = mac_execve_will_transition(oldcred, imgp->vp, 537 interplabel, imgp); 538 credential_changing |= will_transition; 539 #endif 540 541 if (credential_changing && 542 (imgp->vp->v_mount->mnt_flag & MNT_NOSUID) == 0 && 543 (p->p_flag & P_TRACED) == 0) { 544 /* 545 * Turn off syscall tracing for set-id programs, except for 546 * root. Record any set-id flags first to make sure that 547 * we do not regain any tracing during a possible block. 548 */ 549 setsugid(p); 550 #ifdef KTRACE 551 if (p->p_tracevp != NULL && suser_cred(oldcred, SUSER_ALLOWJAIL)) { 552 mtx_lock(&ktrace_mtx); 553 p->p_traceflag = 0; 554 tracevp = p->p_tracevp; 555 p->p_tracevp = NULL; 556 tracecred = p->p_tracecred; 557 p->p_tracecred = NULL; 558 mtx_unlock(&ktrace_mtx); 559 } 560 #endif 561 /* 562 * Close any file descriptors 0..2 that reference procfs, 563 * then make sure file descriptors 0..2 are in use. 564 * 565 * setugidsafety() may call closef() and then pfind() 566 * which may grab the process lock. 567 * fdcheckstd() may call falloc() which may block to 568 * allocate memory, so temporarily drop the process lock. 569 */ 570 PROC_UNLOCK(p); 571 setugidsafety(td); 572 error = fdcheckstd(td); 573 if (error != 0) 574 goto done1; 575 PROC_LOCK(p); 576 /* 577 * Set the new credentials. 578 */ 579 crcopy(newcred, oldcred); 580 if (attr.va_mode & VSUID) 581 change_euid(newcred, euip); 582 if (attr.va_mode & VSGID) 583 change_egid(newcred, attr.va_gid); 584 #ifdef MAC 585 if (will_transition) { 586 mac_execve_transition(oldcred, newcred, imgp->vp, 587 interplabel, imgp); 588 } 589 #endif 590 /* 591 * Implement correct POSIX saved-id behavior. 592 * 593 * XXXMAC: Note that the current logic will save the 594 * uid and gid if a MAC domain transition occurs, even 595 * though maybe it shouldn't. 596 */ 597 change_svuid(newcred, newcred->cr_uid); 598 change_svgid(newcred, newcred->cr_gid); 599 p->p_ucred = newcred; 600 newcred = NULL; 601 } else { 602 if (oldcred->cr_uid == oldcred->cr_ruid && 603 oldcred->cr_gid == oldcred->cr_rgid) 604 p->p_flag &= ~P_SUGID; 605 /* 606 * Implement correct POSIX saved-id behavior. 607 * 608 * XXX: It's not clear that the existing behavior is 609 * POSIX-compliant. A number of sources indicate that the 610 * saved uid/gid should only be updated if the new ruid is 611 * not equal to the old ruid, or the new euid is not equal 612 * to the old euid and the new euid is not equal to the old 613 * ruid. The FreeBSD code always updates the saved uid/gid. 614 * Also, this code uses the new (replaced) euid and egid as 615 * the source, which may or may not be the right ones to use. 616 */ 617 if (oldcred->cr_svuid != oldcred->cr_uid || 618 oldcred->cr_svgid != oldcred->cr_gid) { 619 crcopy(newcred, oldcred); 620 change_svuid(newcred, newcred->cr_uid); 621 change_svgid(newcred, newcred->cr_gid); 622 p->p_ucred = newcred; 623 newcred = NULL; 624 } 625 } 626 627 /* 628 * Store the vp for use in procfs. This vnode was referenced prior 629 * to locking the proc lock. 630 */ 631 textvp = p->p_textvp; 632 p->p_textvp = ndp->ni_vp; 633 634 /* 635 * Notify others that we exec'd, and clear the P_INEXEC flag 636 * as we're now a bona fide freshly-execed process. 637 */ 638 KNOTE_LOCKED(&p->p_klist, NOTE_EXEC); 639 p->p_flag &= ~P_INEXEC; 640 641 /* 642 * If tracing the process, trap to debugger so breakpoints 643 * can be set before the program executes. 644 * Use tdsignal to deliver signal to current thread, use 645 * psignal may cause the signal to be delivered to wrong thread 646 * because that thread will exit, remember we are going to enter 647 * single thread mode. 648 */ 649 if (p->p_flag & P_TRACED) 650 tdsignal(td, SIGTRAP, SIGTARGET_TD); 651 652 /* clear "fork but no exec" flag, as we _are_ execing */ 653 p->p_acflag &= ~AFORK; 654 655 /* Free any previous argument cache */ 656 oldargs = p->p_args; 657 p->p_args = NULL; 658 659 /* Cache arguments if they fit inside our allowance */ 660 if (ps_arg_cache_limit >= i + sizeof(struct pargs)) { 661 bcopy(imgp->args->begin_argv, newargs->ar_args, i); 662 p->p_args = newargs; 663 newargs = NULL; 664 } 665 PROC_UNLOCK(p); 666 667 /* Set values passed into the program in registers. */ 668 if (p->p_sysent->sv_setregs) 669 (*p->p_sysent->sv_setregs)(td, imgp->entry_addr, 670 (u_long)(uintptr_t)stack_base, imgp->ps_strings); 671 else 672 exec_setregs(td, imgp->entry_addr, 673 (u_long)(uintptr_t)stack_base, imgp->ps_strings); 674 675 done1: 676 /* 677 * Free any resources malloc'd earlier that we didn't use. 678 */ 679 uifree(euip); 680 if (newcred == NULL) 681 crfree(oldcred); 682 else 683 crfree(newcred); 684 /* 685 * Handle deferred decrement of ref counts. 686 */ 687 if (textvp != NULL) 688 vrele(textvp); 689 if (ndp->ni_vp && error != 0) 690 vrele(ndp->ni_vp); 691 #ifdef KTRACE 692 if (tracevp != NULL) 693 vrele(tracevp); 694 if (tracecred != NULL) 695 crfree(tracecred); 696 #endif 697 if (oldargs != NULL) 698 pargs_drop(oldargs); 699 if (newargs != NULL) 700 pargs_drop(newargs); 701 if (oldsigacts != NULL) 702 sigacts_free(oldsigacts); 703 704 exec_fail_dealloc: 705 706 /* 707 * free various allocated resources 708 */ 709 if (imgp->firstpage != NULL) 710 exec_unmap_first_page(imgp); 711 712 if (imgp->vp != NULL) { 713 NDFREE(ndp, NDF_ONLY_PNBUF); 714 vput(imgp->vp); 715 } 716 717 if (imgp->object != NULL) 718 vm_object_deallocate(imgp->object); 719 720 if (error == 0) { 721 /* 722 * Stop the process here if its stop event mask has 723 * the S_EXEC bit set. 724 */ 725 STOPEVENT(p, S_EXEC, 0); 726 goto done2; 727 } 728 729 exec_fail: 730 /* we're done here, clear P_INEXEC */ 731 PROC_LOCK(p); 732 p->p_flag &= ~P_INEXEC; 733 PROC_UNLOCK(p); 734 735 if (imgp->vmspace_destroyed) { 736 /* sorry, no more process anymore. exit gracefully */ 737 #ifdef MAC 738 mac_execve_exit(imgp); 739 if (interplabel != NULL) 740 mac_vnode_label_free(interplabel); 741 #endif 742 mtx_unlock(&Giant); 743 exit1(td, W_EXITCODE(0, SIGABRT)); 744 /* NOT REACHED */ 745 error = 0; 746 } 747 done2: 748 #ifdef MAC 749 mac_execve_exit(imgp); 750 if (interplabel != NULL) 751 mac_vnode_label_free(interplabel); 752 #endif 753 mtx_unlock(&Giant); 754 return (error); 755 } 756 757 int 758 exec_map_first_page(imgp) 759 struct image_params *imgp; 760 { 761 int rv, i; 762 int initial_pagein; 763 vm_page_t ma[VM_INITIAL_PAGEIN]; 764 vm_object_t object; 765 766 GIANT_REQUIRED; 767 768 if (imgp->firstpage != NULL) 769 exec_unmap_first_page(imgp); 770 771 object = imgp->vp->v_object; 772 VM_OBJECT_LOCK(object); 773 ma[0] = vm_page_grab(object, 0, VM_ALLOC_NORMAL | VM_ALLOC_RETRY); 774 if ((ma[0]->valid & VM_PAGE_BITS_ALL) != VM_PAGE_BITS_ALL) { 775 initial_pagein = VM_INITIAL_PAGEIN; 776 if (initial_pagein > object->size) 777 initial_pagein = object->size; 778 for (i = 1; i < initial_pagein; i++) { 779 if ((ma[i] = vm_page_lookup(object, i)) != NULL) { 780 if (ma[i]->valid) 781 break; 782 vm_page_lock_queues(); 783 if ((ma[i]->flags & PG_BUSY) || ma[i]->busy) { 784 vm_page_unlock_queues(); 785 break; 786 } 787 vm_page_busy(ma[i]); 788 vm_page_unlock_queues(); 789 } else { 790 ma[i] = vm_page_alloc(object, i, 791 VM_ALLOC_NORMAL); 792 if (ma[i] == NULL) 793 break; 794 } 795 } 796 initial_pagein = i; 797 rv = vm_pager_get_pages(object, ma, initial_pagein, 0); 798 ma[0] = vm_page_lookup(object, 0); 799 if ((rv != VM_PAGER_OK) || (ma[0] == NULL) || 800 (ma[0]->valid == 0)) { 801 if (ma[0]) { 802 vm_page_lock_queues(); 803 pmap_remove_all(ma[0]); 804 vm_page_free(ma[0]); 805 vm_page_unlock_queues(); 806 } 807 VM_OBJECT_UNLOCK(object); 808 return (EIO); 809 } 810 } 811 vm_page_lock_queues(); 812 vm_page_hold(ma[0]); 813 vm_page_wakeup(ma[0]); 814 vm_page_unlock_queues(); 815 VM_OBJECT_UNLOCK(object); 816 817 imgp->firstpage = sf_buf_alloc(ma[0], 0); 818 imgp->image_header = (char *)sf_buf_kva(imgp->firstpage); 819 820 return (0); 821 } 822 823 void 824 exec_unmap_first_page(imgp) 825 struct image_params *imgp; 826 { 827 vm_page_t m; 828 829 if (imgp->firstpage != NULL) { 830 m = sf_buf_page(imgp->firstpage); 831 sf_buf_free(imgp->firstpage); 832 imgp->firstpage = NULL; 833 vm_page_lock_queues(); 834 vm_page_unhold(m); 835 vm_page_unlock_queues(); 836 } 837 } 838 839 /* 840 * Destroy old address space, and allocate a new stack 841 * The new stack is only SGROWSIZ large because it is grown 842 * automatically in trap.c. 843 */ 844 int 845 exec_new_vmspace(imgp, sv) 846 struct image_params *imgp; 847 struct sysentvec *sv; 848 { 849 int error; 850 struct proc *p = imgp->proc; 851 struct vmspace *vmspace = p->p_vmspace; 852 vm_offset_t stack_addr; 853 vm_map_t map; 854 855 GIANT_REQUIRED; 856 857 imgp->vmspace_destroyed = 1; 858 859 /* Called with Giant held, do not depend on it! */ 860 EVENTHANDLER_INVOKE(process_exec, p); 861 862 /* 863 * Here is as good a place as any to do any resource limit cleanups. 864 * This is needed if a 64 bit binary exec's a 32 bit binary - the 865 * data size limit may need to be changed to a value that makes 866 * sense for the 32 bit binary. 867 */ 868 if (sv->sv_fixlimits != NULL) 869 sv->sv_fixlimits(imgp); 870 871 /* 872 * Blow away entire process VM, if address space not shared, 873 * otherwise, create a new VM space so that other threads are 874 * not disrupted 875 */ 876 map = &vmspace->vm_map; 877 if (vmspace->vm_refcnt == 1 && vm_map_min(map) == sv->sv_minuser && 878 vm_map_max(map) == sv->sv_maxuser) { 879 shmexit(vmspace); 880 pmap_remove_pages(vmspace_pmap(vmspace), vm_map_min(map), 881 vm_map_max(map)); 882 vm_map_remove(map, vm_map_min(map), vm_map_max(map)); 883 } else { 884 vmspace_exec(p, sv->sv_minuser, sv->sv_maxuser); 885 vmspace = p->p_vmspace; 886 map = &vmspace->vm_map; 887 } 888 889 /* Allocate a new stack */ 890 stack_addr = sv->sv_usrstack - maxssiz; 891 error = vm_map_stack(map, stack_addr, (vm_size_t)maxssiz, 892 sv->sv_stackprot, VM_PROT_ALL, MAP_STACK_GROWS_DOWN); 893 if (error) 894 return (error); 895 896 #ifdef __ia64__ 897 /* Allocate a new register stack */ 898 stack_addr = IA64_BACKINGSTORE; 899 error = vm_map_stack(map, stack_addr, (vm_size_t)maxssiz, 900 sv->sv_stackprot, VM_PROT_ALL, MAP_STACK_GROWS_UP); 901 if (error) 902 return (error); 903 #endif 904 905 /* vm_ssize and vm_maxsaddr are somewhat antiquated concepts in the 906 * VM_STACK case, but they are still used to monitor the size of the 907 * process stack so we can check the stack rlimit. 908 */ 909 vmspace->vm_ssize = sgrowsiz >> PAGE_SHIFT; 910 vmspace->vm_maxsaddr = (char *)sv->sv_usrstack - maxssiz; 911 912 return (0); 913 } 914 915 /* 916 * Copy out argument and environment strings from the old process 917 * address space into the temporary string buffer. 918 */ 919 int 920 exec_copyin_args(struct image_args *args, char *fname, 921 enum uio_seg segflg, char **argv, char **envv) 922 { 923 char *argp, *envp; 924 int error; 925 size_t length; 926 927 error = 0; 928 929 bzero(args, sizeof(*args)); 930 if (argv == NULL) 931 return (EFAULT); 932 /* 933 * Allocate temporary demand zeroed space for argument and 934 * environment strings: 935 * 936 * o ARG_MAX for argument and environment; 937 * o MAXSHELLCMDLEN for the name of interpreters. 938 */ 939 args->buf = (char *) kmem_alloc_wait(exec_map, 940 PATH_MAX + ARG_MAX + MAXSHELLCMDLEN); 941 if (args->buf == NULL) 942 return (ENOMEM); 943 args->begin_argv = args->buf; 944 args->endp = args->begin_argv; 945 args->stringspace = ARG_MAX; 946 947 args->fname = args->buf + ARG_MAX; 948 949 /* 950 * Copy the file name. 951 */ 952 error = (segflg == UIO_SYSSPACE) ? 953 copystr(fname, args->fname, PATH_MAX, &length) : 954 copyinstr(fname, args->fname, PATH_MAX, &length); 955 if (error != 0) 956 return (error); 957 958 /* 959 * extract arguments first 960 */ 961 while ((argp = (caddr_t) (intptr_t) fuword(argv++))) { 962 if (argp == (caddr_t) -1) 963 return (EFAULT); 964 if ((error = copyinstr(argp, args->endp, 965 args->stringspace, &length))) { 966 if (error == ENAMETOOLONG) 967 return (E2BIG); 968 return (error); 969 } 970 args->stringspace -= length; 971 args->endp += length; 972 args->argc++; 973 } 974 975 args->begin_envv = args->endp; 976 977 /* 978 * extract environment strings 979 */ 980 if (envv) { 981 while ((envp = (caddr_t)(intptr_t)fuword(envv++))) { 982 if (envp == (caddr_t)-1) 983 return (EFAULT); 984 if ((error = copyinstr(envp, args->endp, 985 args->stringspace, &length))) { 986 if (error == ENAMETOOLONG) 987 return (E2BIG); 988 return (error); 989 } 990 args->stringspace -= length; 991 args->endp += length; 992 args->envc++; 993 } 994 } 995 996 return (0); 997 } 998 999 void 1000 exec_free_args(struct image_args *args) 1001 { 1002 1003 if (args->buf) { 1004 kmem_free_wakeup(exec_map, (vm_offset_t)args->buf, 1005 PATH_MAX + ARG_MAX + MAXSHELLCMDLEN); 1006 args->buf = NULL; 1007 } 1008 } 1009 1010 /* 1011 * Copy strings out to the new process address space, constructing 1012 * new arg and env vector tables. Return a pointer to the base 1013 * so that it can be used as the initial stack pointer. 1014 */ 1015 register_t * 1016 exec_copyout_strings(imgp) 1017 struct image_params *imgp; 1018 { 1019 int argc, envc; 1020 char **vectp; 1021 char *stringp, *destp; 1022 register_t *stack_base; 1023 struct ps_strings *arginfo; 1024 struct proc *p; 1025 int szsigcode; 1026 1027 /* 1028 * Calculate string base and vector table pointers. 1029 * Also deal with signal trampoline code for this exec type. 1030 */ 1031 p = imgp->proc; 1032 szsigcode = 0; 1033 arginfo = (struct ps_strings *)p->p_sysent->sv_psstrings; 1034 if (p->p_sysent->sv_szsigcode != NULL) 1035 szsigcode = *(p->p_sysent->sv_szsigcode); 1036 destp = (caddr_t)arginfo - szsigcode - SPARE_USRSPACE - 1037 roundup((ARG_MAX - imgp->args->stringspace), sizeof(char *)); 1038 1039 /* 1040 * install sigcode 1041 */ 1042 if (szsigcode) 1043 copyout(p->p_sysent->sv_sigcode, ((caddr_t)arginfo - 1044 szsigcode), szsigcode); 1045 1046 /* 1047 * If we have a valid auxargs ptr, prepare some room 1048 * on the stack. 1049 */ 1050 if (imgp->auxargs) { 1051 /* 1052 * 'AT_COUNT*2' is size for the ELF Auxargs data. This is for 1053 * lower compatibility. 1054 */ 1055 imgp->auxarg_size = (imgp->auxarg_size) ? imgp->auxarg_size : 1056 (AT_COUNT * 2); 1057 /* 1058 * The '+ 2' is for the null pointers at the end of each of 1059 * the arg and env vector sets,and imgp->auxarg_size is room 1060 * for argument of Runtime loader. 1061 */ 1062 vectp = (char **)(destp - (imgp->args->argc + 1063 imgp->args->envc + 2 + imgp->auxarg_size) * 1064 sizeof(char *)); 1065 1066 } else { 1067 /* 1068 * The '+ 2' is for the null pointers at the end of each of 1069 * the arg and env vector sets 1070 */ 1071 vectp = (char **)(destp - (imgp->args->argc + imgp->args->envc + 2) * 1072 sizeof(char *)); 1073 } 1074 1075 /* 1076 * vectp also becomes our initial stack base 1077 */ 1078 stack_base = (register_t *)vectp; 1079 1080 stringp = imgp->args->begin_argv; 1081 argc = imgp->args->argc; 1082 envc = imgp->args->envc; 1083 1084 /* 1085 * Copy out strings - arguments and environment. 1086 */ 1087 copyout(stringp, destp, ARG_MAX - imgp->args->stringspace); 1088 1089 /* 1090 * Fill in "ps_strings" struct for ps, w, etc. 1091 */ 1092 suword(&arginfo->ps_argvstr, (long)(intptr_t)vectp); 1093 suword(&arginfo->ps_nargvstr, argc); 1094 1095 /* 1096 * Fill in argument portion of vector table. 1097 */ 1098 for (; argc > 0; --argc) { 1099 suword(vectp++, (long)(intptr_t)destp); 1100 while (*stringp++ != 0) 1101 destp++; 1102 destp++; 1103 } 1104 1105 /* a null vector table pointer separates the argp's from the envp's */ 1106 suword(vectp++, 0); 1107 1108 suword(&arginfo->ps_envstr, (long)(intptr_t)vectp); 1109 suword(&arginfo->ps_nenvstr, envc); 1110 1111 /* 1112 * Fill in environment portion of vector table. 1113 */ 1114 for (; envc > 0; --envc) { 1115 suword(vectp++, (long)(intptr_t)destp); 1116 while (*stringp++ != 0) 1117 destp++; 1118 destp++; 1119 } 1120 1121 /* end of vector table is a null pointer */ 1122 suword(vectp, 0); 1123 1124 return (stack_base); 1125 } 1126 1127 /* 1128 * Check permissions of file to execute. 1129 * Called with imgp->vp locked. 1130 * Return 0 for success or error code on failure. 1131 */ 1132 int 1133 exec_check_permissions(imgp) 1134 struct image_params *imgp; 1135 { 1136 struct vnode *vp = imgp->vp; 1137 struct vattr *attr = imgp->attr; 1138 struct thread *td; 1139 int error; 1140 1141 td = curthread; /* XXXKSE */ 1142 1143 /* Get file attributes */ 1144 error = VOP_GETATTR(vp, attr, td->td_ucred, td); 1145 if (error) 1146 return (error); 1147 1148 #ifdef MAC 1149 error = mac_check_vnode_exec(td->td_ucred, imgp->vp, imgp); 1150 if (error) 1151 return (error); 1152 #endif 1153 1154 /* 1155 * 1) Check if file execution is disabled for the filesystem that this 1156 * file resides on. 1157 * 2) Insure that at least one execute bit is on - otherwise root 1158 * will always succeed, and we don't want to happen unless the 1159 * file really is executable. 1160 * 3) Insure that the file is a regular file. 1161 */ 1162 if ((vp->v_mount->mnt_flag & MNT_NOEXEC) || 1163 ((attr->va_mode & 0111) == 0) || 1164 (attr->va_type != VREG)) 1165 return (EACCES); 1166 1167 /* 1168 * Zero length files can't be exec'd 1169 */ 1170 if (attr->va_size == 0) 1171 return (ENOEXEC); 1172 1173 /* 1174 * Check for execute permission to file based on current credentials. 1175 */ 1176 error = VOP_ACCESS(vp, VEXEC, td->td_ucred, td); 1177 if (error) 1178 return (error); 1179 1180 /* 1181 * Check number of open-for-writes on the file and deny execution 1182 * if there are any. 1183 */ 1184 if (vp->v_writecount) 1185 return (ETXTBSY); 1186 1187 /* 1188 * Call filesystem specific open routine (which does nothing in the 1189 * general case). 1190 */ 1191 error = VOP_OPEN(vp, FREAD, td->td_ucred, td, -1); 1192 return (error); 1193 } 1194 1195 /* 1196 * Exec handler registration 1197 */ 1198 int 1199 exec_register(execsw_arg) 1200 const struct execsw *execsw_arg; 1201 { 1202 const struct execsw **es, **xs, **newexecsw; 1203 int count = 2; /* New slot and trailing NULL */ 1204 1205 if (execsw) 1206 for (es = execsw; *es; es++) 1207 count++; 1208 newexecsw = malloc(count * sizeof(*es), M_TEMP, M_WAITOK); 1209 if (newexecsw == NULL) 1210 return (ENOMEM); 1211 xs = newexecsw; 1212 if (execsw) 1213 for (es = execsw; *es; es++) 1214 *xs++ = *es; 1215 *xs++ = execsw_arg; 1216 *xs = NULL; 1217 if (execsw) 1218 free(execsw, M_TEMP); 1219 execsw = newexecsw; 1220 return (0); 1221 } 1222 1223 int 1224 exec_unregister(execsw_arg) 1225 const struct execsw *execsw_arg; 1226 { 1227 const struct execsw **es, **xs, **newexecsw; 1228 int count = 1; 1229 1230 if (execsw == NULL) 1231 panic("unregister with no handlers left?\n"); 1232 1233 for (es = execsw; *es; es++) { 1234 if (*es == execsw_arg) 1235 break; 1236 } 1237 if (*es == NULL) 1238 return (ENOENT); 1239 for (es = execsw; *es; es++) 1240 if (*es != execsw_arg) 1241 count++; 1242 newexecsw = malloc(count * sizeof(*es), M_TEMP, M_WAITOK); 1243 if (newexecsw == NULL) 1244 return (ENOMEM); 1245 xs = newexecsw; 1246 for (es = execsw; *es; es++) 1247 if (*es != execsw_arg) 1248 *xs++ = *es; 1249 *xs = NULL; 1250 if (execsw) 1251 free(execsw, M_TEMP); 1252 execsw = newexecsw; 1253 return (0); 1254 } 1255