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 exec_free_args(args); 247 return (ERESTART); /* Try again later. */ 248 } 249 PROC_UNLOCK(p); 250 } 251 252 error = do_execve(td, args, mac_p); 253 254 if (p->p_flag & P_HADTHREADS) { 255 PROC_LOCK(p); 256 /* 257 * If success, we upgrade to SINGLE_EXIT state to 258 * force other threads to suicide. 259 */ 260 if (error == 0) 261 thread_single(SINGLE_EXIT); 262 else 263 thread_single_end(); 264 PROC_UNLOCK(p); 265 } 266 267 return (error); 268 } 269 270 /* 271 * In-kernel implementation of execve(). All arguments are assumed to be 272 * userspace pointers from the passed thread. 273 * 274 * MPSAFE 275 */ 276 static int 277 do_execve(td, args, mac_p) 278 struct thread *td; 279 struct image_args *args; 280 struct mac *mac_p; 281 { 282 struct proc *p = td->td_proc; 283 struct nameidata nd, *ndp; 284 struct ucred *newcred = NULL, *oldcred; 285 struct uidinfo *euip; 286 register_t *stack_base; 287 int error, len, i; 288 struct image_params image_params, *imgp; 289 struct vattr attr; 290 int (*img_first)(struct image_params *); 291 struct pargs *oldargs = NULL, *newargs = NULL; 292 struct sigacts *oldsigacts, *newsigacts; 293 #ifdef KTRACE 294 struct vnode *tracevp = NULL; 295 struct ucred *tracecred = NULL; 296 #endif 297 struct vnode *textvp = NULL; 298 int credential_changing; 299 int vfslocked; 300 int textset; 301 #ifdef MAC 302 struct label *interplabel = NULL; 303 int will_transition; 304 #endif 305 #ifdef HWPMC_HOOKS 306 struct pmckern_procexec pe; 307 #endif 308 309 vfslocked = 0; 310 imgp = &image_params; 311 312 /* 313 * Lock the process and set the P_INEXEC flag to indicate that 314 * it should be left alone until we're done here. This is 315 * necessary to avoid race conditions - e.g. in ptrace() - 316 * that might allow a local user to illicitly obtain elevated 317 * privileges. 318 */ 319 PROC_LOCK(p); 320 KASSERT((p->p_flag & P_INEXEC) == 0, 321 ("%s(): process already has P_INEXEC flag", __func__)); 322 p->p_flag |= P_INEXEC; 323 PROC_UNLOCK(p); 324 325 /* 326 * Initialize part of the common data 327 */ 328 imgp->proc = p; 329 imgp->execlabel = NULL; 330 imgp->attr = &attr; 331 imgp->entry_addr = 0; 332 imgp->vmspace_destroyed = 0; 333 imgp->interpreted = 0; 334 imgp->interpreter_name = args->buf + PATH_MAX + ARG_MAX; 335 imgp->auxargs = NULL; 336 imgp->vp = NULL; 337 imgp->object = NULL; 338 imgp->firstpage = NULL; 339 imgp->ps_strings = 0; 340 imgp->auxarg_size = 0; 341 imgp->args = args; 342 343 #ifdef MAC 344 error = mac_execve_enter(imgp, mac_p); 345 if (error) 346 goto exec_fail; 347 #endif 348 349 imgp->image_header = NULL; 350 351 /* 352 * Translate the file name. namei() returns a vnode pointer 353 * in ni_vp amoung other things. 354 */ 355 ndp = &nd; 356 NDINIT(ndp, LOOKUP, ISOPEN | LOCKLEAF | FOLLOW | SAVENAME | MPSAFE, 357 UIO_SYSSPACE, args->fname, td); 358 359 interpret: 360 error = namei(ndp); 361 if (error) 362 goto exec_fail; 363 364 vfslocked = NDHASGIANT(ndp); 365 imgp->vp = ndp->ni_vp; 366 367 /* 368 * Check file permissions (also 'opens' file) 369 */ 370 error = exec_check_permissions(imgp); 371 if (error) 372 goto exec_fail_dealloc; 373 374 imgp->object = imgp->vp->v_object; 375 if (imgp->object != NULL) 376 vm_object_reference(imgp->object); 377 378 /* 379 * Set VV_TEXT now so no one can write to the executable while we're 380 * activating it. 381 * 382 * Remember if this was set before and unset it in case this is not 383 * actually an executable image. 384 */ 385 textset = imgp->vp->v_vflag & VV_TEXT; 386 imgp->vp->v_vflag |= VV_TEXT; 387 388 error = exec_map_first_page(imgp); 389 if (error) 390 goto exec_fail_dealloc; 391 392 /* 393 * If the current process has a special image activator it 394 * wants to try first, call it. For example, emulating shell 395 * scripts differently. 396 */ 397 error = -1; 398 if ((img_first = imgp->proc->p_sysent->sv_imgact_try) != NULL) 399 error = img_first(imgp); 400 401 /* 402 * Loop through the list of image activators, calling each one. 403 * An activator returns -1 if there is no match, 0 on success, 404 * and an error otherwise. 405 */ 406 for (i = 0; error == -1 && execsw[i]; ++i) { 407 if (execsw[i]->ex_imgact == NULL || 408 execsw[i]->ex_imgact == img_first) { 409 continue; 410 } 411 error = (*execsw[i]->ex_imgact)(imgp); 412 } 413 414 if (error) { 415 if (error == -1) { 416 if (textset == 0) 417 imgp->vp->v_vflag &= ~VV_TEXT; 418 error = ENOEXEC; 419 } 420 goto exec_fail_dealloc; 421 } 422 423 /* 424 * Special interpreter operation, cleanup and loop up to try to 425 * activate the interpreter. 426 */ 427 if (imgp->interpreted) { 428 exec_unmap_first_page(imgp); 429 /* 430 * VV_TEXT needs to be unset for scripts. There is a short 431 * period before we determine that something is a script where 432 * VV_TEXT will be set. The vnode lock is held over this 433 * entire period so nothing should illegitimately be blocked. 434 */ 435 imgp->vp->v_vflag &= ~VV_TEXT; 436 /* free name buffer and old vnode */ 437 NDFREE(ndp, NDF_ONLY_PNBUF); 438 #ifdef MAC 439 interplabel = mac_vnode_label_alloc(); 440 mac_copy_vnode_label(ndp->ni_vp->v_label, interplabel); 441 #endif 442 vput(ndp->ni_vp); 443 vm_object_deallocate(imgp->object); 444 imgp->object = NULL; 445 VFS_UNLOCK_GIANT(vfslocked); 446 vfslocked = 0; 447 /* set new name to that of the interpreter */ 448 NDINIT(ndp, LOOKUP, LOCKLEAF | FOLLOW | SAVENAME | MPSAFE, 449 UIO_SYSSPACE, imgp->interpreter_name, td); 450 goto interpret; 451 } 452 453 /* 454 * Copy out strings (args and env) and initialize stack base 455 */ 456 if (p->p_sysent->sv_copyout_strings) 457 stack_base = (*p->p_sysent->sv_copyout_strings)(imgp); 458 else 459 stack_base = exec_copyout_strings(imgp); 460 461 /* 462 * If custom stack fixup routine present for this process 463 * let it do the stack setup. 464 * Else stuff argument count as first item on stack 465 */ 466 if (p->p_sysent->sv_fixup != NULL) 467 (*p->p_sysent->sv_fixup)(&stack_base, imgp); 468 else 469 suword(--stack_base, imgp->args->argc); 470 471 /* 472 * For security and other reasons, the file descriptor table cannot 473 * be shared after an exec. 474 */ 475 fdunshare(p, td); 476 477 /* 478 * Malloc things before we need locks. 479 */ 480 newcred = crget(); 481 euip = uifind(attr.va_uid); 482 i = imgp->args->begin_envv - imgp->args->begin_argv; 483 /* Cache arguments if they fit inside our allowance */ 484 if (ps_arg_cache_limit >= i + sizeof(struct pargs)) { 485 newargs = pargs_alloc(i); 486 bcopy(imgp->args->begin_argv, newargs->ar_args, i); 487 } 488 489 /* close files on exec */ 490 fdcloseexec(td); 491 492 /* Get a reference to the vnode prior to locking the proc */ 493 VREF(ndp->ni_vp); 494 495 /* 496 * For security and other reasons, signal handlers cannot 497 * be shared after an exec. The new process gets a copy of the old 498 * handlers. In execsigs(), the new process will have its signals 499 * reset. 500 */ 501 PROC_LOCK(p); 502 if (sigacts_shared(p->p_sigacts)) { 503 oldsigacts = p->p_sigacts; 504 PROC_UNLOCK(p); 505 newsigacts = sigacts_alloc(); 506 sigacts_copy(newsigacts, oldsigacts); 507 PROC_LOCK(p); 508 p->p_sigacts = newsigacts; 509 } else 510 oldsigacts = NULL; 511 512 /* Stop profiling */ 513 stopprofclock(p); 514 515 /* reset caught signals */ 516 execsigs(p); 517 518 /* name this process - nameiexec(p, ndp) */ 519 len = min(ndp->ni_cnd.cn_namelen,MAXCOMLEN); 520 bcopy(ndp->ni_cnd.cn_nameptr, p->p_comm, len); 521 p->p_comm[len] = 0; 522 523 /* 524 * mark as execed, wakeup the process that vforked (if any) and tell 525 * it that it now has its own resources back 526 */ 527 p->p_flag |= P_EXEC; 528 if (p->p_pptr && (p->p_flag & P_PPWAIT)) { 529 p->p_flag &= ~P_PPWAIT; 530 wakeup(p->p_pptr); 531 } 532 533 /* 534 * Implement image setuid/setgid. 535 * 536 * Don't honor setuid/setgid if the filesystem prohibits it or if 537 * the process is being traced. 538 * 539 * XXXMAC: For the time being, use NOSUID to also prohibit 540 * transitions on the file system. 541 */ 542 oldcred = p->p_ucred; 543 credential_changing = 0; 544 credential_changing |= (attr.va_mode & VSUID) && oldcred->cr_uid != 545 attr.va_uid; 546 credential_changing |= (attr.va_mode & VSGID) && oldcred->cr_gid != 547 attr.va_gid; 548 #ifdef MAC 549 will_transition = mac_execve_will_transition(oldcred, imgp->vp, 550 interplabel, imgp); 551 credential_changing |= will_transition; 552 #endif 553 554 if (credential_changing && 555 (imgp->vp->v_mount->mnt_flag & MNT_NOSUID) == 0 && 556 (p->p_flag & P_TRACED) == 0) { 557 /* 558 * Turn off syscall tracing for set-id programs, except for 559 * root. Record any set-id flags first to make sure that 560 * we do not regain any tracing during a possible block. 561 */ 562 setsugid(p); 563 #ifdef KTRACE 564 if (p->p_tracevp != NULL && suser_cred(oldcred, SUSER_ALLOWJAIL)) { 565 mtx_lock(&ktrace_mtx); 566 p->p_traceflag = 0; 567 tracevp = p->p_tracevp; 568 p->p_tracevp = NULL; 569 tracecred = p->p_tracecred; 570 p->p_tracecred = NULL; 571 mtx_unlock(&ktrace_mtx); 572 } 573 #endif 574 /* 575 * Close any file descriptors 0..2 that reference procfs, 576 * then make sure file descriptors 0..2 are in use. 577 * 578 * setugidsafety() may call closef() and then pfind() 579 * which may grab the process lock. 580 * fdcheckstd() may call falloc() which may block to 581 * allocate memory, so temporarily drop the process lock. 582 */ 583 PROC_UNLOCK(p); 584 setugidsafety(td); 585 error = fdcheckstd(td); 586 if (error != 0) 587 goto done1; 588 PROC_LOCK(p); 589 /* 590 * Set the new credentials. 591 */ 592 crcopy(newcred, oldcred); 593 if (attr.va_mode & VSUID) 594 change_euid(newcred, euip); 595 if (attr.va_mode & VSGID) 596 change_egid(newcred, attr.va_gid); 597 #ifdef MAC 598 if (will_transition) { 599 mac_execve_transition(oldcred, newcred, imgp->vp, 600 interplabel, imgp); 601 } 602 #endif 603 /* 604 * Implement correct POSIX saved-id behavior. 605 * 606 * XXXMAC: Note that the current logic will save the 607 * uid and gid if a MAC domain transition occurs, even 608 * though maybe it shouldn't. 609 */ 610 change_svuid(newcred, newcred->cr_uid); 611 change_svgid(newcred, newcred->cr_gid); 612 p->p_ucred = newcred; 613 newcred = NULL; 614 } else { 615 if (oldcred->cr_uid == oldcred->cr_ruid && 616 oldcred->cr_gid == oldcred->cr_rgid) 617 p->p_flag &= ~P_SUGID; 618 /* 619 * Implement correct POSIX saved-id behavior. 620 * 621 * XXX: It's not clear that the existing behavior is 622 * POSIX-compliant. A number of sources indicate that the 623 * saved uid/gid should only be updated if the new ruid is 624 * not equal to the old ruid, or the new euid is not equal 625 * to the old euid and the new euid is not equal to the old 626 * ruid. The FreeBSD code always updates the saved uid/gid. 627 * Also, this code uses the new (replaced) euid and egid as 628 * the source, which may or may not be the right ones to use. 629 */ 630 if (oldcred->cr_svuid != oldcred->cr_uid || 631 oldcred->cr_svgid != oldcred->cr_gid) { 632 crcopy(newcred, oldcred); 633 change_svuid(newcred, newcred->cr_uid); 634 change_svgid(newcred, newcred->cr_gid); 635 p->p_ucred = newcred; 636 newcred = NULL; 637 } 638 } 639 640 /* 641 * Store the vp for use in procfs. This vnode was referenced prior 642 * to locking the proc lock. 643 */ 644 textvp = p->p_textvp; 645 p->p_textvp = ndp->ni_vp; 646 647 /* 648 * Notify others that we exec'd, and clear the P_INEXEC flag 649 * as we're now a bona fide freshly-execed process. 650 */ 651 KNOTE_LOCKED(&p->p_klist, NOTE_EXEC); 652 p->p_flag &= ~P_INEXEC; 653 654 /* 655 * If tracing the process, trap to debugger so breakpoints 656 * can be set before the program executes. 657 * Use tdsignal to deliver signal to current thread, use 658 * psignal may cause the signal to be delivered to wrong thread 659 * because that thread will exit, remember we are going to enter 660 * single thread mode. 661 */ 662 if (p->p_flag & P_TRACED) 663 tdsignal(p, td, SIGTRAP, NULL); 664 665 /* clear "fork but no exec" flag, as we _are_ execing */ 666 p->p_acflag &= ~AFORK; 667 668 /* 669 * Free any previous argument cache and replace it with 670 * the new argument cache, if any. 671 */ 672 oldargs = p->p_args; 673 p->p_args = newargs; 674 newargs = NULL; 675 676 #ifdef HWPMC_HOOKS 677 /* 678 * Check if system-wide sampling is in effect or if the 679 * current process is using PMCs. If so, do exec() time 680 * processing. This processing needs to happen AFTER the 681 * P_INEXEC flag is cleared. 682 * 683 * The proc lock needs to be released before taking the PMC 684 * SX. 685 */ 686 if (PMC_SYSTEM_SAMPLING_ACTIVE() || PMC_PROC_IS_USING_PMCS(p)) { 687 PROC_UNLOCK(p); 688 pe.pm_credentialschanged = credential_changing; 689 pe.pm_entryaddr = imgp->entry_addr; 690 691 PMC_CALL_HOOK_X(td, PMC_FN_PROCESS_EXEC, (void *) &pe); 692 } else 693 PROC_UNLOCK(p); 694 #else /* !HWPMC_HOOKS */ 695 PROC_UNLOCK(p); 696 #endif 697 698 /* Set values passed into the program in registers. */ 699 if (p->p_sysent->sv_setregs) 700 (*p->p_sysent->sv_setregs)(td, imgp->entry_addr, 701 (u_long)(uintptr_t)stack_base, imgp->ps_strings); 702 else 703 exec_setregs(td, imgp->entry_addr, 704 (u_long)(uintptr_t)stack_base, imgp->ps_strings); 705 706 vfs_mark_atime(imgp->vp, td); 707 708 done1: 709 /* 710 * Free any resources malloc'd earlier that we didn't use. 711 */ 712 uifree(euip); 713 if (newcred == NULL) 714 crfree(oldcred); 715 else 716 crfree(newcred); 717 /* 718 * Handle deferred decrement of ref counts. 719 */ 720 if (textvp != NULL) { 721 int tvfslocked; 722 723 tvfslocked = VFS_LOCK_GIANT(textvp->v_mount); 724 vrele(textvp); 725 VFS_UNLOCK_GIANT(tvfslocked); 726 } 727 if (ndp->ni_vp && error != 0) 728 vrele(ndp->ni_vp); 729 #ifdef KTRACE 730 if (tracevp != NULL) 731 vrele(tracevp); 732 if (tracecred != NULL) 733 crfree(tracecred); 734 #endif 735 if (oldargs != NULL) 736 pargs_drop(oldargs); 737 if (newargs != NULL) 738 pargs_drop(newargs); 739 if (oldsigacts != NULL) 740 sigacts_free(oldsigacts); 741 742 exec_fail_dealloc: 743 744 /* 745 * free various allocated resources 746 */ 747 if (imgp->firstpage != NULL) 748 exec_unmap_first_page(imgp); 749 750 if (imgp->vp != NULL) { 751 NDFREE(ndp, NDF_ONLY_PNBUF); 752 vput(imgp->vp); 753 } 754 755 if (imgp->object != NULL) 756 vm_object_deallocate(imgp->object); 757 758 if (error == 0) { 759 /* 760 * Stop the process here if its stop event mask has 761 * the S_EXEC bit set. 762 */ 763 STOPEVENT(p, S_EXEC, 0); 764 goto done2; 765 } 766 767 exec_fail: 768 /* we're done here, clear P_INEXEC */ 769 PROC_LOCK(p); 770 p->p_flag &= ~P_INEXEC; 771 PROC_UNLOCK(p); 772 773 done2: 774 #ifdef MAC 775 mac_execve_exit(imgp); 776 if (interplabel != NULL) 777 mac_vnode_label_free(interplabel); 778 #endif 779 VFS_UNLOCK_GIANT(vfslocked); 780 exec_free_args(args); 781 782 if (error && imgp->vmspace_destroyed) { 783 /* sorry, no more process anymore. exit gracefully */ 784 exit1(td, W_EXITCODE(0, SIGABRT)); 785 /* NOT REACHED */ 786 } 787 return (error); 788 } 789 790 int 791 exec_map_first_page(imgp) 792 struct image_params *imgp; 793 { 794 int rv, i; 795 int initial_pagein; 796 vm_page_t ma[VM_INITIAL_PAGEIN]; 797 vm_object_t object; 798 799 if (imgp->firstpage != NULL) 800 exec_unmap_first_page(imgp); 801 802 object = imgp->vp->v_object; 803 if (object == NULL) 804 return (EACCES); 805 VM_OBJECT_LOCK(object); 806 ma[0] = vm_page_grab(object, 0, VM_ALLOC_NORMAL | VM_ALLOC_RETRY); 807 if ((ma[0]->valid & VM_PAGE_BITS_ALL) != VM_PAGE_BITS_ALL) { 808 initial_pagein = VM_INITIAL_PAGEIN; 809 if (initial_pagein > object->size) 810 initial_pagein = object->size; 811 for (i = 1; i < initial_pagein; i++) { 812 if ((ma[i] = vm_page_lookup(object, i)) != NULL) { 813 if (ma[i]->valid) 814 break; 815 if ((ma[i]->flags & PG_BUSY) || ma[i]->busy) 816 break; 817 vm_page_lock_queues(); 818 vm_page_busy(ma[i]); 819 vm_page_unlock_queues(); 820 } else { 821 ma[i] = vm_page_alloc(object, i, 822 VM_ALLOC_NORMAL); 823 if (ma[i] == NULL) 824 break; 825 } 826 } 827 initial_pagein = i; 828 rv = vm_pager_get_pages(object, ma, initial_pagein, 0); 829 ma[0] = vm_page_lookup(object, 0); 830 if ((rv != VM_PAGER_OK) || (ma[0] == NULL) || 831 (ma[0]->valid == 0)) { 832 if (ma[0]) { 833 vm_page_lock_queues(); 834 vm_page_free(ma[0]); 835 vm_page_unlock_queues(); 836 } 837 VM_OBJECT_UNLOCK(object); 838 return (EIO); 839 } 840 } 841 vm_page_lock_queues(); 842 vm_page_hold(ma[0]); 843 vm_page_wakeup(ma[0]); 844 vm_page_unlock_queues(); 845 VM_OBJECT_UNLOCK(object); 846 847 imgp->firstpage = sf_buf_alloc(ma[0], 0); 848 imgp->image_header = (char *)sf_buf_kva(imgp->firstpage); 849 850 return (0); 851 } 852 853 void 854 exec_unmap_first_page(imgp) 855 struct image_params *imgp; 856 { 857 vm_page_t m; 858 859 if (imgp->firstpage != NULL) { 860 m = sf_buf_page(imgp->firstpage); 861 sf_buf_free(imgp->firstpage); 862 imgp->firstpage = NULL; 863 vm_page_lock_queues(); 864 vm_page_unhold(m); 865 vm_page_unlock_queues(); 866 } 867 } 868 869 /* 870 * Destroy old address space, and allocate a new stack 871 * The new stack is only SGROWSIZ large because it is grown 872 * automatically in trap.c. 873 */ 874 int 875 exec_new_vmspace(imgp, sv) 876 struct image_params *imgp; 877 struct sysentvec *sv; 878 { 879 int error; 880 struct proc *p = imgp->proc; 881 struct vmspace *vmspace = p->p_vmspace; 882 vm_offset_t stack_addr; 883 vm_map_t map; 884 885 imgp->vmspace_destroyed = 1; 886 887 /* Called with Giant held, do not depend on it! */ 888 EVENTHANDLER_INVOKE(process_exec, p); 889 890 /* 891 * Here is as good a place as any to do any resource limit cleanups. 892 * This is needed if a 64 bit binary exec's a 32 bit binary - the 893 * data size limit may need to be changed to a value that makes 894 * sense for the 32 bit binary. 895 */ 896 if (sv->sv_fixlimits != NULL) 897 sv->sv_fixlimits(p); 898 899 /* 900 * Blow away entire process VM, if address space not shared, 901 * otherwise, create a new VM space so that other threads are 902 * not disrupted 903 */ 904 map = &vmspace->vm_map; 905 if (vmspace->vm_refcnt == 1 && vm_map_min(map) == sv->sv_minuser && 906 vm_map_max(map) == sv->sv_maxuser) { 907 shmexit(vmspace); 908 pmap_remove_pages(vmspace_pmap(vmspace)); 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 goto err_exit; 984 985 /* 986 * extract arguments first 987 */ 988 while ((argp = (caddr_t) (intptr_t) fuword(argv++))) { 989 if (argp == (caddr_t) -1) { 990 error = EFAULT; 991 goto err_exit; 992 } 993 if ((error = copyinstr(argp, args->endp, 994 args->stringspace, &length))) { 995 if (error == ENAMETOOLONG) 996 error = E2BIG; 997 goto err_exit; 998 } 999 args->stringspace -= length; 1000 args->endp += length; 1001 args->argc++; 1002 } 1003 1004 args->begin_envv = args->endp; 1005 1006 /* 1007 * extract environment strings 1008 */ 1009 if (envv) { 1010 while ((envp = (caddr_t)(intptr_t)fuword(envv++))) { 1011 if (envp == (caddr_t)-1) { 1012 error = EFAULT; 1013 goto err_exit; 1014 } 1015 if ((error = copyinstr(envp, args->endp, 1016 args->stringspace, &length))) { 1017 if (error == ENAMETOOLONG) 1018 error = E2BIG; 1019 goto err_exit; 1020 } 1021 args->stringspace -= length; 1022 args->endp += length; 1023 args->envc++; 1024 } 1025 } 1026 1027 return (0); 1028 1029 err_exit: 1030 exec_free_args(args); 1031 return (error); 1032 } 1033 1034 static void 1035 exec_free_args(struct image_args *args) 1036 { 1037 1038 if (args->buf) { 1039 kmem_free_wakeup(exec_map, (vm_offset_t)args->buf, 1040 PATH_MAX + ARG_MAX + MAXSHELLCMDLEN); 1041 args->buf = NULL; 1042 } 1043 } 1044 1045 /* 1046 * Copy strings out to the new process address space, constructing 1047 * new arg and env vector tables. Return a pointer to the base 1048 * so that it can be used as the initial stack pointer. 1049 */ 1050 register_t * 1051 exec_copyout_strings(imgp) 1052 struct image_params *imgp; 1053 { 1054 int argc, envc; 1055 char **vectp; 1056 char *stringp, *destp; 1057 register_t *stack_base; 1058 struct ps_strings *arginfo; 1059 struct proc *p; 1060 int szsigcode; 1061 1062 /* 1063 * Calculate string base and vector table pointers. 1064 * Also deal with signal trampoline code for this exec type. 1065 */ 1066 p = imgp->proc; 1067 szsigcode = 0; 1068 arginfo = (struct ps_strings *)p->p_sysent->sv_psstrings; 1069 if (p->p_sysent->sv_szsigcode != NULL) 1070 szsigcode = *(p->p_sysent->sv_szsigcode); 1071 destp = (caddr_t)arginfo - szsigcode - SPARE_USRSPACE - 1072 roundup((ARG_MAX - imgp->args->stringspace), sizeof(char *)); 1073 1074 /* 1075 * install sigcode 1076 */ 1077 if (szsigcode) 1078 copyout(p->p_sysent->sv_sigcode, ((caddr_t)arginfo - 1079 szsigcode), szsigcode); 1080 1081 /* 1082 * If we have a valid auxargs ptr, prepare some room 1083 * on the stack. 1084 */ 1085 if (imgp->auxargs) { 1086 /* 1087 * 'AT_COUNT*2' is size for the ELF Auxargs data. This is for 1088 * lower compatibility. 1089 */ 1090 imgp->auxarg_size = (imgp->auxarg_size) ? imgp->auxarg_size : 1091 (AT_COUNT * 2); 1092 /* 1093 * The '+ 2' is for the null pointers at the end of each of 1094 * the arg and env vector sets,and imgp->auxarg_size is room 1095 * for argument of Runtime loader. 1096 */ 1097 vectp = (char **)(destp - (imgp->args->argc + 1098 imgp->args->envc + 2 + imgp->auxarg_size) * 1099 sizeof(char *)); 1100 1101 } else { 1102 /* 1103 * The '+ 2' is for the null pointers at the end of each of 1104 * the arg and env vector sets 1105 */ 1106 vectp = (char **)(destp - (imgp->args->argc + imgp->args->envc + 2) * 1107 sizeof(char *)); 1108 } 1109 1110 /* 1111 * vectp also becomes our initial stack base 1112 */ 1113 stack_base = (register_t *)vectp; 1114 1115 stringp = imgp->args->begin_argv; 1116 argc = imgp->args->argc; 1117 envc = imgp->args->envc; 1118 1119 /* 1120 * Copy out strings - arguments and environment. 1121 */ 1122 copyout(stringp, destp, ARG_MAX - imgp->args->stringspace); 1123 1124 /* 1125 * Fill in "ps_strings" struct for ps, w, etc. 1126 */ 1127 suword(&arginfo->ps_argvstr, (long)(intptr_t)vectp); 1128 suword(&arginfo->ps_nargvstr, argc); 1129 1130 /* 1131 * Fill in argument portion of vector table. 1132 */ 1133 for (; argc > 0; --argc) { 1134 suword(vectp++, (long)(intptr_t)destp); 1135 while (*stringp++ != 0) 1136 destp++; 1137 destp++; 1138 } 1139 1140 /* a null vector table pointer separates the argp's from the envp's */ 1141 suword(vectp++, 0); 1142 1143 suword(&arginfo->ps_envstr, (long)(intptr_t)vectp); 1144 suword(&arginfo->ps_nenvstr, envc); 1145 1146 /* 1147 * Fill in environment portion of vector table. 1148 */ 1149 for (; envc > 0; --envc) { 1150 suword(vectp++, (long)(intptr_t)destp); 1151 while (*stringp++ != 0) 1152 destp++; 1153 destp++; 1154 } 1155 1156 /* end of vector table is a null pointer */ 1157 suword(vectp, 0); 1158 1159 return (stack_base); 1160 } 1161 1162 /* 1163 * Check permissions of file to execute. 1164 * Called with imgp->vp locked. 1165 * Return 0 for success or error code on failure. 1166 */ 1167 int 1168 exec_check_permissions(imgp) 1169 struct image_params *imgp; 1170 { 1171 struct vnode *vp = imgp->vp; 1172 struct vattr *attr = imgp->attr; 1173 struct thread *td; 1174 int error; 1175 1176 td = curthread; /* XXXKSE */ 1177 1178 /* Get file attributes */ 1179 error = VOP_GETATTR(vp, attr, td->td_ucred, td); 1180 if (error) 1181 return (error); 1182 1183 #ifdef MAC 1184 error = mac_check_vnode_exec(td->td_ucred, imgp->vp, imgp); 1185 if (error) 1186 return (error); 1187 #endif 1188 1189 /* 1190 * 1) Check if file execution is disabled for the filesystem that this 1191 * file resides on. 1192 * 2) Insure that at least one execute bit is on - otherwise root 1193 * will always succeed, and we don't want to happen unless the 1194 * file really is executable. 1195 * 3) Insure that the file is a regular file. 1196 */ 1197 if ((vp->v_mount->mnt_flag & MNT_NOEXEC) || 1198 ((attr->va_mode & 0111) == 0) || 1199 (attr->va_type != VREG)) 1200 return (EACCES); 1201 1202 /* 1203 * Zero length files can't be exec'd 1204 */ 1205 if (attr->va_size == 0) 1206 return (ENOEXEC); 1207 1208 /* 1209 * Check for execute permission to file based on current credentials. 1210 */ 1211 error = VOP_ACCESS(vp, VEXEC, td->td_ucred, td); 1212 if (error) 1213 return (error); 1214 1215 /* 1216 * Check number of open-for-writes on the file and deny execution 1217 * if there are any. 1218 */ 1219 if (vp->v_writecount) 1220 return (ETXTBSY); 1221 1222 /* 1223 * Call filesystem specific open routine (which does nothing in the 1224 * general case). 1225 */ 1226 error = VOP_OPEN(vp, FREAD, td->td_ucred, td, -1); 1227 return (error); 1228 } 1229 1230 /* 1231 * Exec handler registration 1232 */ 1233 int 1234 exec_register(execsw_arg) 1235 const struct execsw *execsw_arg; 1236 { 1237 const struct execsw **es, **xs, **newexecsw; 1238 int count = 2; /* New slot and trailing NULL */ 1239 1240 if (execsw) 1241 for (es = execsw; *es; es++) 1242 count++; 1243 newexecsw = malloc(count * sizeof(*es), M_TEMP, M_WAITOK); 1244 if (newexecsw == NULL) 1245 return (ENOMEM); 1246 xs = newexecsw; 1247 if (execsw) 1248 for (es = execsw; *es; es++) 1249 *xs++ = *es; 1250 *xs++ = execsw_arg; 1251 *xs = NULL; 1252 if (execsw) 1253 free(execsw, M_TEMP); 1254 execsw = newexecsw; 1255 return (0); 1256 } 1257 1258 int 1259 exec_unregister(execsw_arg) 1260 const struct execsw *execsw_arg; 1261 { 1262 const struct execsw **es, **xs, **newexecsw; 1263 int count = 1; 1264 1265 if (execsw == NULL) 1266 panic("unregister with no handlers left?\n"); 1267 1268 for (es = execsw; *es; es++) { 1269 if (*es == execsw_arg) 1270 break; 1271 } 1272 if (*es == NULL) 1273 return (ENOENT); 1274 for (es = execsw; *es; es++) 1275 if (*es != execsw_arg) 1276 count++; 1277 newexecsw = malloc(count * sizeof(*es), M_TEMP, M_WAITOK); 1278 if (newexecsw == NULL) 1279 return (ENOMEM); 1280 xs = newexecsw; 1281 for (es = execsw; *es; es++) 1282 if (*es != execsw_arg) 1283 *xs++ = *es; 1284 *xs = NULL; 1285 if (execsw) 1286 free(execsw, M_TEMP); 1287 execsw = newexecsw; 1288 return (0); 1289 } 1290