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_hwpmc_hooks.h" 31 #include "opt_ktrace.h" 32 #include "opt_mac.h" 33 34 #include <sys/param.h> 35 #include <sys/systm.h> 36 #include <sys/eventhandler.h> 37 #include <sys/lock.h> 38 #include <sys/mutex.h> 39 #include <sys/sysproto.h> 40 #include <sys/signalvar.h> 41 #include <sys/kernel.h> 42 #include <sys/mac.h> 43 #include <sys/mount.h> 44 #include <sys/filedesc.h> 45 #include <sys/fcntl.h> 46 #include <sys/acct.h> 47 #include <sys/exec.h> 48 #include <sys/imgact.h> 49 #include <sys/imgact_elf.h> 50 #include <sys/wait.h> 51 #include <sys/malloc.h> 52 #include <sys/proc.h> 53 #include <sys/pioctl.h> 54 #include <sys/namei.h> 55 #include <sys/resourcevar.h> 56 #include <sys/sf_buf.h> 57 #include <sys/syscallsubr.h> 58 #include <sys/sysent.h> 59 #include <sys/shm.h> 60 #include <sys/sysctl.h> 61 #include <sys/vnode.h> 62 #ifdef KTRACE 63 #include <sys/ktrace.h> 64 #endif 65 66 #include <vm/vm.h> 67 #include <vm/vm_param.h> 68 #include <vm/pmap.h> 69 #include <vm/vm_page.h> 70 #include <vm/vm_map.h> 71 #include <vm/vm_kern.h> 72 #include <vm/vm_extern.h> 73 #include <vm/vm_object.h> 74 #include <vm/vm_pager.h> 75 76 #ifdef HWPMC_HOOKS 77 #include <sys/pmckern.h> 78 #endif 79 80 #include <machine/reg.h> 81 82 MALLOC_DEFINE(M_PARGS, "proc-args", "Process arguments"); 83 84 static int sysctl_kern_ps_strings(SYSCTL_HANDLER_ARGS); 85 static int sysctl_kern_usrstack(SYSCTL_HANDLER_ARGS); 86 static int sysctl_kern_stackprot(SYSCTL_HANDLER_ARGS); 87 static int do_execve(struct thread *td, struct image_args *args, 88 struct mac *mac_p); 89 static void exec_free_args(struct image_args *); 90 91 /* XXX This should be vm_size_t. */ 92 SYSCTL_PROC(_kern, KERN_PS_STRINGS, ps_strings, CTLTYPE_ULONG|CTLFLAG_RD, 93 NULL, 0, sysctl_kern_ps_strings, "LU", ""); 94 95 /* XXX This should be vm_size_t. */ 96 SYSCTL_PROC(_kern, KERN_USRSTACK, usrstack, CTLTYPE_ULONG|CTLFLAG_RD, 97 NULL, 0, sysctl_kern_usrstack, "LU", ""); 98 99 SYSCTL_PROC(_kern, OID_AUTO, stackprot, CTLTYPE_INT|CTLFLAG_RD, 100 NULL, 0, sysctl_kern_stackprot, "I", ""); 101 102 u_long ps_arg_cache_limit = PAGE_SIZE / 16; 103 SYSCTL_ULONG(_kern, OID_AUTO, ps_arg_cache_limit, CTLFLAG_RW, 104 &ps_arg_cache_limit, 0, ""); 105 106 static int 107 sysctl_kern_ps_strings(SYSCTL_HANDLER_ARGS) 108 { 109 struct proc *p; 110 int error; 111 112 p = curproc; 113 #ifdef SCTL_MASK32 114 if (req->flags & SCTL_MASK32) { 115 unsigned int val; 116 val = (unsigned int)p->p_sysent->sv_psstrings; 117 error = SYSCTL_OUT(req, &val, sizeof(val)); 118 } else 119 #endif 120 error = SYSCTL_OUT(req, &p->p_sysent->sv_psstrings, 121 sizeof(p->p_sysent->sv_psstrings)); 122 return error; 123 } 124 125 static int 126 sysctl_kern_usrstack(SYSCTL_HANDLER_ARGS) 127 { 128 struct proc *p; 129 int error; 130 131 p = curproc; 132 #ifdef SCTL_MASK32 133 if (req->flags & SCTL_MASK32) { 134 unsigned int val; 135 val = (unsigned int)p->p_sysent->sv_usrstack; 136 error = SYSCTL_OUT(req, &val, sizeof(val)); 137 } else 138 #endif 139 error = SYSCTL_OUT(req, &p->p_sysent->sv_usrstack, 140 sizeof(p->p_sysent->sv_usrstack)); 141 return error; 142 } 143 144 static int 145 sysctl_kern_stackprot(SYSCTL_HANDLER_ARGS) 146 { 147 struct proc *p; 148 149 p = curproc; 150 return (SYSCTL_OUT(req, &p->p_sysent->sv_stackprot, 151 sizeof(p->p_sysent->sv_stackprot))); 152 } 153 154 /* 155 * Each of the items is a pointer to a `const struct execsw', hence the 156 * double pointer here. 157 */ 158 static const struct execsw **execsw; 159 160 #ifndef _SYS_SYSPROTO_H_ 161 struct execve_args { 162 char *fname; 163 char **argv; 164 char **envv; 165 }; 166 #endif 167 168 /* 169 * MPSAFE 170 */ 171 int 172 execve(td, uap) 173 struct thread *td; 174 struct execve_args /* { 175 char *fname; 176 char **argv; 177 char **envv; 178 } */ *uap; 179 { 180 int error; 181 struct image_args args; 182 183 error = exec_copyin_args(&args, uap->fname, UIO_USERSPACE, 184 uap->argv, uap->envv); 185 if (error == 0) 186 error = kern_execve(td, &args, NULL); 187 return (error); 188 } 189 190 #ifndef _SYS_SYSPROTO_H_ 191 struct __mac_execve_args { 192 char *fname; 193 char **argv; 194 char **envv; 195 struct mac *mac_p; 196 }; 197 #endif 198 199 /* 200 * MPSAFE 201 */ 202 int 203 __mac_execve(td, uap) 204 struct thread *td; 205 struct __mac_execve_args /* { 206 char *fname; 207 char **argv; 208 char **envv; 209 struct mac *mac_p; 210 } */ *uap; 211 { 212 #ifdef MAC 213 int error; 214 struct image_args args; 215 216 error = exec_copyin_args(&args, uap->fname, UIO_USERSPACE, 217 uap->argv, uap->envv); 218 if (error == 0) 219 error = kern_execve(td, &args, uap->mac_p); 220 return (error); 221 #else 222 return (ENOSYS); 223 #endif 224 } 225 226 /* 227 * XXX: kern_execve has the astonishing property of not always 228 * returning to the caller. If sufficiently bad things happen during 229 * the call to do_execve(), it can end up calling exit1(); as a result, 230 * callers must avoid doing anything which they might need to undo 231 * (e.g., allocating memory). 232 */ 233 int 234 kern_execve(td, args, mac_p) 235 struct thread *td; 236 struct image_args *args; 237 struct mac *mac_p; 238 { 239 struct proc *p = td->td_proc; 240 int error; 241 242 if (p->p_flag & P_HADTHREADS) { 243 PROC_LOCK(p); 244 if (thread_single(SINGLE_BOUNDARY)) { 245 PROC_UNLOCK(p); 246 return (ERESTART); /* Try again later. */ 247 } 248 PROC_UNLOCK(p); 249 } 250 251 error = do_execve(td, args, mac_p); 252 253 if (p->p_flag & P_HADTHREADS) { 254 PROC_LOCK(p); 255 /* 256 * If success, we upgrade to SINGLE_EXIT state to 257 * force other threads to suicide. 258 */ 259 if (error == 0) 260 thread_single(SINGLE_EXIT); 261 else 262 thread_single_end(); 263 PROC_UNLOCK(p); 264 } 265 266 return (error); 267 } 268 269 /* 270 * In-kernel implementation of execve(). All arguments are assumed to be 271 * userspace pointers from the passed thread. 272 * 273 * MPSAFE 274 */ 275 static int 276 do_execve(td, args, mac_p) 277 struct thread *td; 278 struct image_args *args; 279 struct mac *mac_p; 280 { 281 struct proc *p = td->td_proc; 282 struct nameidata nd, *ndp; 283 struct ucred *newcred = NULL, *oldcred; 284 struct uidinfo *euip; 285 register_t *stack_base; 286 int error, len, i; 287 struct image_params image_params, *imgp; 288 struct vattr attr; 289 int (*img_first)(struct image_params *); 290 struct pargs *oldargs = NULL, *newargs = NULL; 291 struct sigacts *oldsigacts, *newsigacts; 292 #ifdef KTRACE 293 struct vnode *tracevp = NULL; 294 struct ucred *tracecred = NULL; 295 #endif 296 struct vnode *textvp = NULL; 297 int credential_changing; 298 int vfslocked; 299 int textset; 300 #ifdef MAC 301 struct label *interplabel = NULL; 302 int will_transition; 303 #endif 304 #ifdef HWPMC_HOOKS 305 struct pmckern_procexec pe; 306 #endif 307 308 vfslocked = 0; 309 imgp = &image_params; 310 311 /* 312 * Lock the process and set the P_INEXEC flag to indicate that 313 * it should be left alone until we're done here. This is 314 * necessary to avoid race conditions - e.g. in ptrace() - 315 * that might allow a local user to illicitly obtain elevated 316 * privileges. 317 */ 318 PROC_LOCK(p); 319 KASSERT((p->p_flag & P_INEXEC) == 0, 320 ("%s(): process already has P_INEXEC flag", __func__)); 321 p->p_flag |= P_INEXEC; 322 PROC_UNLOCK(p); 323 324 /* 325 * Initialize part of the common data 326 */ 327 imgp->proc = p; 328 imgp->execlabel = NULL; 329 imgp->attr = &attr; 330 imgp->entry_addr = 0; 331 imgp->vmspace_destroyed = 0; 332 imgp->interpreted = 0; 333 imgp->interpreter_name = args->buf + PATH_MAX + ARG_MAX; 334 imgp->auxargs = NULL; 335 imgp->vp = NULL; 336 imgp->object = NULL; 337 imgp->firstpage = NULL; 338 imgp->ps_strings = 0; 339 imgp->auxarg_size = 0; 340 imgp->args = args; 341 342 #ifdef MAC 343 error = mac_execve_enter(imgp, mac_p); 344 if (error) 345 goto exec_fail; 346 #endif 347 348 imgp->image_header = NULL; 349 350 /* 351 * Translate the file name. namei() returns a vnode pointer 352 * in ni_vp amoung other things. 353 */ 354 ndp = &nd; 355 NDINIT(ndp, LOOKUP, ISOPEN | LOCKLEAF | FOLLOW | SAVENAME | MPSAFE, 356 UIO_SYSSPACE, args->fname, td); 357 358 interpret: 359 error = namei(ndp); 360 if (error) 361 goto exec_fail; 362 363 vfslocked = NDHASGIANT(ndp); 364 imgp->vp = ndp->ni_vp; 365 366 /* 367 * Check file permissions (also 'opens' file) 368 */ 369 error = exec_check_permissions(imgp); 370 if (error) 371 goto exec_fail_dealloc; 372 373 imgp->object = imgp->vp->v_object; 374 if (imgp->object != NULL) 375 vm_object_reference(imgp->object); 376 377 /* 378 * Set VV_TEXT now so no one can write to the executable while we're 379 * activating it. 380 * 381 * Remember if this was set before and unset it in case this is not 382 * actually an executable image. 383 */ 384 textset = imgp->vp->v_vflag & VV_TEXT; 385 imgp->vp->v_vflag |= VV_TEXT; 386 387 error = exec_map_first_page(imgp); 388 if (error) 389 goto exec_fail_dealloc; 390 391 /* 392 * If the current process has a special image activator it 393 * wants to try first, call it. For example, emulating shell 394 * scripts differently. 395 */ 396 error = -1; 397 if ((img_first = imgp->proc->p_sysent->sv_imgact_try) != NULL) 398 error = img_first(imgp); 399 400 /* 401 * Loop through the list of image activators, calling each one. 402 * An activator returns -1 if there is no match, 0 on success, 403 * and an error otherwise. 404 */ 405 for (i = 0; error == -1 && execsw[i]; ++i) { 406 if (execsw[i]->ex_imgact == NULL || 407 execsw[i]->ex_imgact == img_first) { 408 continue; 409 } 410 error = (*execsw[i]->ex_imgact)(imgp); 411 } 412 413 if (error) { 414 if (error == -1) { 415 if (textset == 0) 416 imgp->vp->v_vflag &= ~VV_TEXT; 417 error = ENOEXEC; 418 } 419 goto exec_fail_dealloc; 420 } 421 422 /* 423 * Special interpreter operation, cleanup and loop up to try to 424 * activate the interpreter. 425 */ 426 if (imgp->interpreted) { 427 exec_unmap_first_page(imgp); 428 /* 429 * VV_TEXT needs to be unset for scripts. There is a short 430 * period before we determine that something is a script where 431 * VV_TEXT will be set. The vnode lock is held over this 432 * entire period so nothing should illegitimately be blocked. 433 */ 434 imgp->vp->v_vflag &= ~VV_TEXT; 435 /* free name buffer and old vnode */ 436 NDFREE(ndp, NDF_ONLY_PNBUF); 437 #ifdef MAC 438 interplabel = mac_vnode_label_alloc(); 439 mac_copy_vnode_label(ndp->ni_vp->v_label, interplabel); 440 #endif 441 vput(ndp->ni_vp); 442 vm_object_deallocate(imgp->object); 443 imgp->object = NULL; 444 VFS_UNLOCK_GIANT(vfslocked); 445 vfslocked = 0; 446 /* set new name to that of the interpreter */ 447 NDINIT(ndp, LOOKUP, LOCKLEAF | FOLLOW | SAVENAME | MPSAFE, 448 UIO_SYSSPACE, imgp->interpreter_name, td); 449 goto interpret; 450 } 451 452 /* 453 * Copy out strings (args and env) and initialize stack base 454 */ 455 if (p->p_sysent->sv_copyout_strings) 456 stack_base = (*p->p_sysent->sv_copyout_strings)(imgp); 457 else 458 stack_base = exec_copyout_strings(imgp); 459 460 /* 461 * If custom stack fixup routine present for this process 462 * let it do the stack setup. 463 * Else stuff argument count as first item on stack 464 */ 465 if (p->p_sysent->sv_fixup != NULL) 466 (*p->p_sysent->sv_fixup)(&stack_base, imgp); 467 else 468 suword(--stack_base, imgp->args->argc); 469 470 /* 471 * For security and other reasons, the file descriptor table cannot 472 * be shared after an exec. 473 */ 474 fdunshare(p, td); 475 476 /* 477 * Malloc things before we need locks. 478 */ 479 newcred = crget(); 480 euip = uifind(attr.va_uid); 481 i = imgp->args->begin_envv - imgp->args->begin_argv; 482 /* Cache arguments if they fit inside our allowance */ 483 if (ps_arg_cache_limit >= i + sizeof(struct pargs)) { 484 newargs = pargs_alloc(i); 485 bcopy(imgp->args->begin_argv, newargs->ar_args, i); 486 } 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(p, td, SIGTRAP, NULL); 663 664 /* clear "fork but no exec" flag, as we _are_ execing */ 665 p->p_acflag &= ~AFORK; 666 667 /* 668 * Free any previous argument cache and replace it with 669 * the new argument cache, if any. 670 */ 671 oldargs = p->p_args; 672 p->p_args = newargs; 673 newargs = NULL; 674 675 #ifdef HWPMC_HOOKS 676 /* 677 * Check if system-wide sampling is in effect or if the 678 * current process is using PMCs. If so, do exec() time 679 * processing. This processing needs to happen AFTER the 680 * P_INEXEC flag is cleared. 681 * 682 * The proc lock needs to be released before taking the PMC 683 * SX. 684 */ 685 if (PMC_SYSTEM_SAMPLING_ACTIVE() || PMC_PROC_IS_USING_PMCS(p)) { 686 PROC_UNLOCK(p); 687 pe.pm_credentialschanged = credential_changing; 688 pe.pm_entryaddr = imgp->entry_addr; 689 690 PMC_CALL_HOOK_X(td, PMC_FN_PROCESS_EXEC, (void *) &pe); 691 } else 692 PROC_UNLOCK(p); 693 #else /* !HWPMC_HOOKS */ 694 PROC_UNLOCK(p); 695 #endif 696 697 /* Set values passed into the program in registers. */ 698 if (p->p_sysent->sv_setregs) 699 (*p->p_sysent->sv_setregs)(td, imgp->entry_addr, 700 (u_long)(uintptr_t)stack_base, imgp->ps_strings); 701 else 702 exec_setregs(td, imgp->entry_addr, 703 (u_long)(uintptr_t)stack_base, imgp->ps_strings); 704 705 vfs_mark_atime(imgp->vp, td); 706 707 done1: 708 /* 709 * Free any resources malloc'd earlier that we didn't use. 710 */ 711 uifree(euip); 712 if (newcred == NULL) 713 crfree(oldcred); 714 else 715 crfree(newcred); 716 /* 717 * Handle deferred decrement of ref counts. 718 */ 719 if (textvp != NULL) { 720 int tvfslocked; 721 722 tvfslocked = VFS_LOCK_GIANT(textvp->v_mount); 723 vrele(textvp); 724 VFS_UNLOCK_GIANT(tvfslocked); 725 } 726 if (ndp->ni_vp && error != 0) 727 vrele(ndp->ni_vp); 728 #ifdef KTRACE 729 if (tracevp != NULL) 730 vrele(tracevp); 731 if (tracecred != NULL) 732 crfree(tracecred); 733 #endif 734 if (oldargs != NULL) 735 pargs_drop(oldargs); 736 if (newargs != NULL) 737 pargs_drop(newargs); 738 if (oldsigacts != NULL) 739 sigacts_free(oldsigacts); 740 741 exec_fail_dealloc: 742 743 /* 744 * free various allocated resources 745 */ 746 if (imgp->firstpage != NULL) 747 exec_unmap_first_page(imgp); 748 749 if (imgp->vp != NULL) { 750 NDFREE(ndp, NDF_ONLY_PNBUF); 751 vput(imgp->vp); 752 } 753 754 if (imgp->object != NULL) 755 vm_object_deallocate(imgp->object); 756 757 if (error == 0) { 758 /* 759 * Stop the process here if its stop event mask has 760 * the S_EXEC bit set. 761 */ 762 STOPEVENT(p, S_EXEC, 0); 763 goto done2; 764 } 765 766 exec_fail: 767 /* we're done here, clear P_INEXEC */ 768 PROC_LOCK(p); 769 p->p_flag &= ~P_INEXEC; 770 PROC_UNLOCK(p); 771 772 done2: 773 #ifdef MAC 774 mac_execve_exit(imgp); 775 if (interplabel != NULL) 776 mac_vnode_label_free(interplabel); 777 #endif 778 VFS_UNLOCK_GIANT(vfslocked); 779 exec_free_args(args); 780 781 if (error && imgp->vmspace_destroyed) { 782 /* sorry, no more process anymore. exit gracefully */ 783 exit1(td, W_EXITCODE(0, SIGABRT)); 784 /* NOT REACHED */ 785 } 786 return (error); 787 } 788 789 int 790 exec_map_first_page(imgp) 791 struct image_params *imgp; 792 { 793 int rv, i; 794 int initial_pagein; 795 vm_page_t ma[VM_INITIAL_PAGEIN]; 796 vm_object_t object; 797 798 if (imgp->firstpage != NULL) 799 exec_unmap_first_page(imgp); 800 801 object = imgp->vp->v_object; 802 if (object == NULL) 803 return (EACCES); 804 VM_OBJECT_LOCK(object); 805 ma[0] = vm_page_grab(object, 0, VM_ALLOC_NORMAL | VM_ALLOC_RETRY); 806 if ((ma[0]->valid & VM_PAGE_BITS_ALL) != VM_PAGE_BITS_ALL) { 807 initial_pagein = VM_INITIAL_PAGEIN; 808 if (initial_pagein > object->size) 809 initial_pagein = object->size; 810 for (i = 1; i < initial_pagein; i++) { 811 if ((ma[i] = vm_page_lookup(object, i)) != NULL) { 812 if (ma[i]->valid) 813 break; 814 if ((ma[i]->flags & PG_BUSY) || ma[i]->busy) 815 break; 816 vm_page_lock_queues(); 817 vm_page_busy(ma[i]); 818 vm_page_unlock_queues(); 819 } else { 820 ma[i] = vm_page_alloc(object, i, 821 VM_ALLOC_NORMAL); 822 if (ma[i] == NULL) 823 break; 824 } 825 } 826 initial_pagein = i; 827 rv = vm_pager_get_pages(object, ma, initial_pagein, 0); 828 ma[0] = vm_page_lookup(object, 0); 829 if ((rv != VM_PAGER_OK) || (ma[0] == NULL) || 830 (ma[0]->valid == 0)) { 831 if (ma[0]) { 832 vm_page_lock_queues(); 833 vm_page_free(ma[0]); 834 vm_page_unlock_queues(); 835 } 836 VM_OBJECT_UNLOCK(object); 837 return (EIO); 838 } 839 } 840 vm_page_lock_queues(); 841 vm_page_hold(ma[0]); 842 vm_page_wakeup(ma[0]); 843 vm_page_unlock_queues(); 844 VM_OBJECT_UNLOCK(object); 845 846 imgp->firstpage = sf_buf_alloc(ma[0], 0); 847 imgp->image_header = (char *)sf_buf_kva(imgp->firstpage); 848 849 return (0); 850 } 851 852 void 853 exec_unmap_first_page(imgp) 854 struct image_params *imgp; 855 { 856 vm_page_t m; 857 858 if (imgp->firstpage != NULL) { 859 m = sf_buf_page(imgp->firstpage); 860 sf_buf_free(imgp->firstpage); 861 imgp->firstpage = NULL; 862 vm_page_lock_queues(); 863 vm_page_unhold(m); 864 vm_page_unlock_queues(); 865 } 866 } 867 868 /* 869 * Destroy old address space, and allocate a new stack 870 * The new stack is only SGROWSIZ large because it is grown 871 * automatically in trap.c. 872 */ 873 int 874 exec_new_vmspace(imgp, sv) 875 struct image_params *imgp; 876 struct sysentvec *sv; 877 { 878 int error; 879 struct proc *p = imgp->proc; 880 struct vmspace *vmspace = p->p_vmspace; 881 vm_offset_t stack_addr; 882 vm_map_t map; 883 884 imgp->vmspace_destroyed = 1; 885 886 /* Called with Giant held, do not depend on it! */ 887 EVENTHANDLER_INVOKE(process_exec, p); 888 889 /* 890 * Here is as good a place as any to do any resource limit cleanups. 891 * This is needed if a 64 bit binary exec's a 32 bit binary - the 892 * data size limit may need to be changed to a value that makes 893 * sense for the 32 bit binary. 894 */ 895 if (sv->sv_fixlimits != NULL) 896 sv->sv_fixlimits(p); 897 898 /* 899 * Blow away entire process VM, if address space not shared, 900 * otherwise, create a new VM space so that other threads are 901 * not disrupted 902 */ 903 map = &vmspace->vm_map; 904 if (vmspace->vm_refcnt == 1 && vm_map_min(map) == sv->sv_minuser && 905 vm_map_max(map) == sv->sv_maxuser) { 906 shmexit(vmspace); 907 pmap_remove_pages(vmspace_pmap(vmspace), vm_map_min(map), 908 vm_map_max(map)); 909 vm_map_remove(map, vm_map_min(map), vm_map_max(map)); 910 } else { 911 vmspace_exec(p, sv->sv_minuser, sv->sv_maxuser); 912 vmspace = p->p_vmspace; 913 map = &vmspace->vm_map; 914 } 915 916 /* Allocate a new stack */ 917 stack_addr = sv->sv_usrstack - maxssiz; 918 error = vm_map_stack(map, stack_addr, (vm_size_t)maxssiz, 919 sv->sv_stackprot, VM_PROT_ALL, MAP_STACK_GROWS_DOWN); 920 if (error) 921 return (error); 922 923 #ifdef __ia64__ 924 /* Allocate a new register stack */ 925 stack_addr = IA64_BACKINGSTORE; 926 error = vm_map_stack(map, stack_addr, (vm_size_t)maxssiz, 927 sv->sv_stackprot, VM_PROT_ALL, MAP_STACK_GROWS_UP); 928 if (error) 929 return (error); 930 #endif 931 932 /* vm_ssize and vm_maxsaddr are somewhat antiquated concepts in the 933 * VM_STACK case, but they are still used to monitor the size of the 934 * process stack so we can check the stack rlimit. 935 */ 936 vmspace->vm_ssize = sgrowsiz >> PAGE_SHIFT; 937 vmspace->vm_maxsaddr = (char *)sv->sv_usrstack - maxssiz; 938 939 return (0); 940 } 941 942 /* 943 * Copy out argument and environment strings from the old process 944 * address space into the temporary string buffer. 945 */ 946 int 947 exec_copyin_args(struct image_args *args, char *fname, 948 enum uio_seg segflg, char **argv, char **envv) 949 { 950 char *argp, *envp; 951 int error; 952 size_t length; 953 954 error = 0; 955 956 bzero(args, sizeof(*args)); 957 if (argv == NULL) 958 return (EFAULT); 959 /* 960 * Allocate temporary demand zeroed space for argument and 961 * environment strings: 962 * 963 * o ARG_MAX for argument and environment; 964 * o MAXSHELLCMDLEN for the name of interpreters. 965 */ 966 args->buf = (char *) kmem_alloc_wait(exec_map, 967 PATH_MAX + ARG_MAX + MAXSHELLCMDLEN); 968 if (args->buf == NULL) 969 return (ENOMEM); 970 args->begin_argv = args->buf; 971 args->endp = args->begin_argv; 972 args->stringspace = ARG_MAX; 973 974 args->fname = args->buf + ARG_MAX; 975 976 /* 977 * Copy the file name. 978 */ 979 error = (segflg == UIO_SYSSPACE) ? 980 copystr(fname, args->fname, PATH_MAX, &length) : 981 copyinstr(fname, args->fname, PATH_MAX, &length); 982 if (error != 0) 983 return (error); 984 985 /* 986 * extract arguments first 987 */ 988 while ((argp = (caddr_t) (intptr_t) fuword(argv++))) { 989 if (argp == (caddr_t) -1) 990 return (EFAULT); 991 if ((error = copyinstr(argp, args->endp, 992 args->stringspace, &length))) { 993 if (error == ENAMETOOLONG) 994 return (E2BIG); 995 return (error); 996 } 997 args->stringspace -= length; 998 args->endp += length; 999 args->argc++; 1000 } 1001 1002 args->begin_envv = args->endp; 1003 1004 /* 1005 * extract environment strings 1006 */ 1007 if (envv) { 1008 while ((envp = (caddr_t)(intptr_t)fuword(envv++))) { 1009 if (envp == (caddr_t)-1) 1010 return (EFAULT); 1011 if ((error = copyinstr(envp, args->endp, 1012 args->stringspace, &length))) { 1013 if (error == ENAMETOOLONG) 1014 return (E2BIG); 1015 return (error); 1016 } 1017 args->stringspace -= length; 1018 args->endp += length; 1019 args->envc++; 1020 } 1021 } 1022 1023 return (0); 1024 } 1025 1026 static void 1027 exec_free_args(struct image_args *args) 1028 { 1029 1030 if (args->buf) { 1031 kmem_free_wakeup(exec_map, (vm_offset_t)args->buf, 1032 PATH_MAX + ARG_MAX + MAXSHELLCMDLEN); 1033 args->buf = NULL; 1034 } 1035 } 1036 1037 /* 1038 * Copy strings out to the new process address space, constructing 1039 * new arg and env vector tables. Return a pointer to the base 1040 * so that it can be used as the initial stack pointer. 1041 */ 1042 register_t * 1043 exec_copyout_strings(imgp) 1044 struct image_params *imgp; 1045 { 1046 int argc, envc; 1047 char **vectp; 1048 char *stringp, *destp; 1049 register_t *stack_base; 1050 struct ps_strings *arginfo; 1051 struct proc *p; 1052 int szsigcode; 1053 1054 /* 1055 * Calculate string base and vector table pointers. 1056 * Also deal with signal trampoline code for this exec type. 1057 */ 1058 p = imgp->proc; 1059 szsigcode = 0; 1060 arginfo = (struct ps_strings *)p->p_sysent->sv_psstrings; 1061 if (p->p_sysent->sv_szsigcode != NULL) 1062 szsigcode = *(p->p_sysent->sv_szsigcode); 1063 destp = (caddr_t)arginfo - szsigcode - SPARE_USRSPACE - 1064 roundup((ARG_MAX - imgp->args->stringspace), sizeof(char *)); 1065 1066 /* 1067 * install sigcode 1068 */ 1069 if (szsigcode) 1070 copyout(p->p_sysent->sv_sigcode, ((caddr_t)arginfo - 1071 szsigcode), szsigcode); 1072 1073 /* 1074 * If we have a valid auxargs ptr, prepare some room 1075 * on the stack. 1076 */ 1077 if (imgp->auxargs) { 1078 /* 1079 * 'AT_COUNT*2' is size for the ELF Auxargs data. This is for 1080 * lower compatibility. 1081 */ 1082 imgp->auxarg_size = (imgp->auxarg_size) ? imgp->auxarg_size : 1083 (AT_COUNT * 2); 1084 /* 1085 * The '+ 2' is for the null pointers at the end of each of 1086 * the arg and env vector sets,and imgp->auxarg_size is room 1087 * for argument of Runtime loader. 1088 */ 1089 vectp = (char **)(destp - (imgp->args->argc + 1090 imgp->args->envc + 2 + imgp->auxarg_size) * 1091 sizeof(char *)); 1092 1093 } else { 1094 /* 1095 * The '+ 2' is for the null pointers at the end of each of 1096 * the arg and env vector sets 1097 */ 1098 vectp = (char **)(destp - (imgp->args->argc + imgp->args->envc + 2) * 1099 sizeof(char *)); 1100 } 1101 1102 /* 1103 * vectp also becomes our initial stack base 1104 */ 1105 stack_base = (register_t *)vectp; 1106 1107 stringp = imgp->args->begin_argv; 1108 argc = imgp->args->argc; 1109 envc = imgp->args->envc; 1110 1111 /* 1112 * Copy out strings - arguments and environment. 1113 */ 1114 copyout(stringp, destp, ARG_MAX - imgp->args->stringspace); 1115 1116 /* 1117 * Fill in "ps_strings" struct for ps, w, etc. 1118 */ 1119 suword(&arginfo->ps_argvstr, (long)(intptr_t)vectp); 1120 suword(&arginfo->ps_nargvstr, argc); 1121 1122 /* 1123 * Fill in argument portion of vector table. 1124 */ 1125 for (; argc > 0; --argc) { 1126 suword(vectp++, (long)(intptr_t)destp); 1127 while (*stringp++ != 0) 1128 destp++; 1129 destp++; 1130 } 1131 1132 /* a null vector table pointer separates the argp's from the envp's */ 1133 suword(vectp++, 0); 1134 1135 suword(&arginfo->ps_envstr, (long)(intptr_t)vectp); 1136 suword(&arginfo->ps_nenvstr, envc); 1137 1138 /* 1139 * Fill in environment portion of vector table. 1140 */ 1141 for (; envc > 0; --envc) { 1142 suword(vectp++, (long)(intptr_t)destp); 1143 while (*stringp++ != 0) 1144 destp++; 1145 destp++; 1146 } 1147 1148 /* end of vector table is a null pointer */ 1149 suword(vectp, 0); 1150 1151 return (stack_base); 1152 } 1153 1154 /* 1155 * Check permissions of file to execute. 1156 * Called with imgp->vp locked. 1157 * Return 0 for success or error code on failure. 1158 */ 1159 int 1160 exec_check_permissions(imgp) 1161 struct image_params *imgp; 1162 { 1163 struct vnode *vp = imgp->vp; 1164 struct vattr *attr = imgp->attr; 1165 struct thread *td; 1166 int error; 1167 1168 td = curthread; /* XXXKSE */ 1169 1170 /* Get file attributes */ 1171 error = VOP_GETATTR(vp, attr, td->td_ucred, td); 1172 if (error) 1173 return (error); 1174 1175 #ifdef MAC 1176 error = mac_check_vnode_exec(td->td_ucred, imgp->vp, imgp); 1177 if (error) 1178 return (error); 1179 #endif 1180 1181 /* 1182 * 1) Check if file execution is disabled for the filesystem that this 1183 * file resides on. 1184 * 2) Insure that at least one execute bit is on - otherwise root 1185 * will always succeed, and we don't want to happen unless the 1186 * file really is executable. 1187 * 3) Insure that the file is a regular file. 1188 */ 1189 if ((vp->v_mount->mnt_flag & MNT_NOEXEC) || 1190 ((attr->va_mode & 0111) == 0) || 1191 (attr->va_type != VREG)) 1192 return (EACCES); 1193 1194 /* 1195 * Zero length files can't be exec'd 1196 */ 1197 if (attr->va_size == 0) 1198 return (ENOEXEC); 1199 1200 /* 1201 * Check for execute permission to file based on current credentials. 1202 */ 1203 error = VOP_ACCESS(vp, VEXEC, td->td_ucred, td); 1204 if (error) 1205 return (error); 1206 1207 /* 1208 * Check number of open-for-writes on the file and deny execution 1209 * if there are any. 1210 */ 1211 if (vp->v_writecount) 1212 return (ETXTBSY); 1213 1214 /* 1215 * Call filesystem specific open routine (which does nothing in the 1216 * general case). 1217 */ 1218 error = VOP_OPEN(vp, FREAD, td->td_ucred, td, -1); 1219 return (error); 1220 } 1221 1222 /* 1223 * Exec handler registration 1224 */ 1225 int 1226 exec_register(execsw_arg) 1227 const struct execsw *execsw_arg; 1228 { 1229 const struct execsw **es, **xs, **newexecsw; 1230 int count = 2; /* New slot and trailing NULL */ 1231 1232 if (execsw) 1233 for (es = execsw; *es; es++) 1234 count++; 1235 newexecsw = malloc(count * sizeof(*es), M_TEMP, M_WAITOK); 1236 if (newexecsw == NULL) 1237 return (ENOMEM); 1238 xs = newexecsw; 1239 if (execsw) 1240 for (es = execsw; *es; es++) 1241 *xs++ = *es; 1242 *xs++ = execsw_arg; 1243 *xs = NULL; 1244 if (execsw) 1245 free(execsw, M_TEMP); 1246 execsw = newexecsw; 1247 return (0); 1248 } 1249 1250 int 1251 exec_unregister(execsw_arg) 1252 const struct execsw *execsw_arg; 1253 { 1254 const struct execsw **es, **xs, **newexecsw; 1255 int count = 1; 1256 1257 if (execsw == NULL) 1258 panic("unregister with no handlers left?\n"); 1259 1260 for (es = execsw; *es; es++) { 1261 if (*es == execsw_arg) 1262 break; 1263 } 1264 if (*es == NULL) 1265 return (ENOENT); 1266 for (es = execsw; *es; es++) 1267 if (*es != execsw_arg) 1268 count++; 1269 newexecsw = malloc(count * sizeof(*es), M_TEMP, M_WAITOK); 1270 if (newexecsw == NULL) 1271 return (ENOMEM); 1272 xs = newexecsw; 1273 for (es = execsw; *es; es++) 1274 if (*es != execsw_arg) 1275 *xs++ = *es; 1276 *xs = NULL; 1277 if (execsw) 1278 free(execsw, M_TEMP); 1279 execsw = newexecsw; 1280 return (0); 1281 } 1282