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 AUDITVNODE1, 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 VOP_UNLOCK(imgp->vp, 0, td); 491 fdcloseexec(td); 492 vn_lock(imgp->vp, LK_EXCLUSIVE | LK_RETRY, td); 493 494 /* Get a reference to the vnode prior to locking the proc */ 495 VREF(ndp->ni_vp); 496 497 /* 498 * For security and other reasons, signal handlers cannot 499 * be shared after an exec. The new process gets a copy of the old 500 * handlers. In execsigs(), the new process will have its signals 501 * reset. 502 */ 503 PROC_LOCK(p); 504 if (sigacts_shared(p->p_sigacts)) { 505 oldsigacts = p->p_sigacts; 506 PROC_UNLOCK(p); 507 newsigacts = sigacts_alloc(); 508 sigacts_copy(newsigacts, oldsigacts); 509 PROC_LOCK(p); 510 p->p_sigacts = newsigacts; 511 } else 512 oldsigacts = NULL; 513 514 /* Stop profiling */ 515 stopprofclock(p); 516 517 /* reset caught signals */ 518 execsigs(p); 519 520 /* name this process - nameiexec(p, ndp) */ 521 len = min(ndp->ni_cnd.cn_namelen,MAXCOMLEN); 522 bcopy(ndp->ni_cnd.cn_nameptr, p->p_comm, len); 523 p->p_comm[len] = 0; 524 525 /* 526 * mark as execed, wakeup the process that vforked (if any) and tell 527 * it that it now has its own resources back 528 */ 529 p->p_flag |= P_EXEC; 530 if (p->p_pptr && (p->p_flag & P_PPWAIT)) { 531 p->p_flag &= ~P_PPWAIT; 532 wakeup(p->p_pptr); 533 } 534 535 /* 536 * Implement image setuid/setgid. 537 * 538 * Don't honor setuid/setgid if the filesystem prohibits it or if 539 * the process is being traced. 540 * 541 * XXXMAC: For the time being, use NOSUID to also prohibit 542 * transitions on the file system. 543 */ 544 oldcred = p->p_ucred; 545 credential_changing = 0; 546 credential_changing |= (attr.va_mode & VSUID) && oldcred->cr_uid != 547 attr.va_uid; 548 credential_changing |= (attr.va_mode & VSGID) && oldcred->cr_gid != 549 attr.va_gid; 550 #ifdef MAC 551 will_transition = mac_execve_will_transition(oldcred, imgp->vp, 552 interplabel, imgp); 553 credential_changing |= will_transition; 554 #endif 555 556 if (credential_changing && 557 (imgp->vp->v_mount->mnt_flag & MNT_NOSUID) == 0 && 558 (p->p_flag & P_TRACED) == 0) { 559 /* 560 * Turn off syscall tracing for set-id programs, except for 561 * root. Record any set-id flags first to make sure that 562 * we do not regain any tracing during a possible block. 563 */ 564 setsugid(p); 565 #ifdef KTRACE 566 if (p->p_tracevp != NULL && suser_cred(oldcred, SUSER_ALLOWJAIL)) { 567 mtx_lock(&ktrace_mtx); 568 p->p_traceflag = 0; 569 tracevp = p->p_tracevp; 570 p->p_tracevp = NULL; 571 tracecred = p->p_tracecred; 572 p->p_tracecred = NULL; 573 mtx_unlock(&ktrace_mtx); 574 } 575 #endif 576 /* 577 * Close any file descriptors 0..2 that reference procfs, 578 * then make sure file descriptors 0..2 are in use. 579 * 580 * setugidsafety() may call closef() and then pfind() 581 * which may grab the process lock. 582 * fdcheckstd() may call falloc() which may block to 583 * allocate memory, so temporarily drop the process lock. 584 */ 585 PROC_UNLOCK(p); 586 setugidsafety(td); 587 VOP_UNLOCK(imgp->vp, 0, td); 588 error = fdcheckstd(td); 589 vn_lock(imgp->vp, LK_EXCLUSIVE | LK_RETRY, td); 590 if (error != 0) 591 goto done1; 592 PROC_LOCK(p); 593 /* 594 * Set the new credentials. 595 */ 596 crcopy(newcred, oldcred); 597 if (attr.va_mode & VSUID) 598 change_euid(newcred, euip); 599 if (attr.va_mode & VSGID) 600 change_egid(newcred, attr.va_gid); 601 #ifdef MAC 602 if (will_transition) { 603 mac_execve_transition(oldcred, newcred, imgp->vp, 604 interplabel, imgp); 605 } 606 #endif 607 /* 608 * Implement correct POSIX saved-id behavior. 609 * 610 * XXXMAC: Note that the current logic will save the 611 * uid and gid if a MAC domain transition occurs, even 612 * though maybe it shouldn't. 613 */ 614 change_svuid(newcred, newcred->cr_uid); 615 change_svgid(newcred, newcred->cr_gid); 616 p->p_ucred = newcred; 617 newcred = NULL; 618 } else { 619 if (oldcred->cr_uid == oldcred->cr_ruid && 620 oldcred->cr_gid == oldcred->cr_rgid) 621 p->p_flag &= ~P_SUGID; 622 /* 623 * Implement correct POSIX saved-id behavior. 624 * 625 * XXX: It's not clear that the existing behavior is 626 * POSIX-compliant. A number of sources indicate that the 627 * saved uid/gid should only be updated if the new ruid is 628 * not equal to the old ruid, or the new euid is not equal 629 * to the old euid and the new euid is not equal to the old 630 * ruid. The FreeBSD code always updates the saved uid/gid. 631 * Also, this code uses the new (replaced) euid and egid as 632 * the source, which may or may not be the right ones to use. 633 */ 634 if (oldcred->cr_svuid != oldcred->cr_uid || 635 oldcred->cr_svgid != oldcred->cr_gid) { 636 crcopy(newcred, oldcred); 637 change_svuid(newcred, newcred->cr_uid); 638 change_svgid(newcred, newcred->cr_gid); 639 p->p_ucred = newcred; 640 newcred = NULL; 641 } 642 } 643 644 /* 645 * Store the vp for use in procfs. This vnode was referenced prior 646 * to locking the proc lock. 647 */ 648 textvp = p->p_textvp; 649 p->p_textvp = ndp->ni_vp; 650 651 /* 652 * Notify others that we exec'd, and clear the P_INEXEC flag 653 * as we're now a bona fide freshly-execed process. 654 */ 655 KNOTE_LOCKED(&p->p_klist, NOTE_EXEC); 656 p->p_flag &= ~P_INEXEC; 657 658 /* 659 * If tracing the process, trap to debugger so breakpoints 660 * can be set before the program executes. 661 * Use tdsignal to deliver signal to current thread, use 662 * psignal may cause the signal to be delivered to wrong thread 663 * because that thread will exit, remember we are going to enter 664 * single thread mode. 665 */ 666 if (p->p_flag & P_TRACED) 667 tdsignal(p, td, SIGTRAP, NULL); 668 669 /* clear "fork but no exec" flag, as we _are_ execing */ 670 p->p_acflag &= ~AFORK; 671 672 /* 673 * Free any previous argument cache and replace it with 674 * the new argument cache, if any. 675 */ 676 oldargs = p->p_args; 677 p->p_args = newargs; 678 newargs = NULL; 679 680 #ifdef HWPMC_HOOKS 681 /* 682 * Check if system-wide sampling is in effect or if the 683 * current process is using PMCs. If so, do exec() time 684 * processing. This processing needs to happen AFTER the 685 * P_INEXEC flag is cleared. 686 * 687 * The proc lock needs to be released before taking the PMC 688 * SX. 689 */ 690 if (PMC_SYSTEM_SAMPLING_ACTIVE() || PMC_PROC_IS_USING_PMCS(p)) { 691 PROC_UNLOCK(p); 692 pe.pm_credentialschanged = credential_changing; 693 pe.pm_entryaddr = imgp->entry_addr; 694 695 PMC_CALL_HOOK_X(td, PMC_FN_PROCESS_EXEC, (void *) &pe); 696 } else 697 PROC_UNLOCK(p); 698 #else /* !HWPMC_HOOKS */ 699 PROC_UNLOCK(p); 700 #endif 701 702 /* Set values passed into the program in registers. */ 703 if (p->p_sysent->sv_setregs) 704 (*p->p_sysent->sv_setregs)(td, imgp->entry_addr, 705 (u_long)(uintptr_t)stack_base, imgp->ps_strings); 706 else 707 exec_setregs(td, imgp->entry_addr, 708 (u_long)(uintptr_t)stack_base, imgp->ps_strings); 709 710 vfs_mark_atime(imgp->vp, td); 711 712 done1: 713 /* 714 * Free any resources malloc'd earlier that we didn't use. 715 */ 716 uifree(euip); 717 if (newcred == NULL) 718 crfree(oldcred); 719 else 720 crfree(newcred); 721 VOP_UNLOCK(imgp->vp, 0, td); 722 /* 723 * Handle deferred decrement of ref counts. 724 */ 725 if (textvp != NULL) { 726 int tvfslocked; 727 728 tvfslocked = VFS_LOCK_GIANT(textvp->v_mount); 729 vrele(textvp); 730 VFS_UNLOCK_GIANT(tvfslocked); 731 } 732 if (ndp->ni_vp && error != 0) 733 vrele(ndp->ni_vp); 734 #ifdef KTRACE 735 if (tracevp != NULL) 736 vrele(tracevp); 737 if (tracecred != NULL) 738 crfree(tracecred); 739 #endif 740 vn_lock(imgp->vp, LK_EXCLUSIVE | LK_RETRY, td); 741 if (oldargs != NULL) 742 pargs_drop(oldargs); 743 if (newargs != NULL) 744 pargs_drop(newargs); 745 if (oldsigacts != NULL) 746 sigacts_free(oldsigacts); 747 748 exec_fail_dealloc: 749 750 /* 751 * free various allocated resources 752 */ 753 if (imgp->firstpage != NULL) 754 exec_unmap_first_page(imgp); 755 756 if (imgp->vp != NULL) { 757 NDFREE(ndp, NDF_ONLY_PNBUF); 758 vput(imgp->vp); 759 } 760 761 if (imgp->object != NULL) 762 vm_object_deallocate(imgp->object); 763 764 if (error == 0) { 765 /* 766 * Stop the process here if its stop event mask has 767 * the S_EXEC bit set. 768 */ 769 STOPEVENT(p, S_EXEC, 0); 770 goto done2; 771 } 772 773 exec_fail: 774 /* we're done here, clear P_INEXEC */ 775 PROC_LOCK(p); 776 p->p_flag &= ~P_INEXEC; 777 PROC_UNLOCK(p); 778 779 done2: 780 #ifdef MAC 781 mac_execve_exit(imgp); 782 if (interplabel != NULL) 783 mac_vnode_label_free(interplabel); 784 #endif 785 VFS_UNLOCK_GIANT(vfslocked); 786 exec_free_args(args); 787 788 if (error && imgp->vmspace_destroyed) { 789 /* sorry, no more process anymore. exit gracefully */ 790 exit1(td, W_EXITCODE(0, SIGABRT)); 791 /* NOT REACHED */ 792 } 793 return (error); 794 } 795 796 int 797 exec_map_first_page(imgp) 798 struct image_params *imgp; 799 { 800 int rv, i; 801 int initial_pagein; 802 vm_page_t ma[VM_INITIAL_PAGEIN]; 803 vm_object_t object; 804 805 if (imgp->firstpage != NULL) 806 exec_unmap_first_page(imgp); 807 808 object = imgp->vp->v_object; 809 if (object == NULL) 810 return (EACCES); 811 VM_OBJECT_LOCK(object); 812 ma[0] = vm_page_grab(object, 0, VM_ALLOC_NORMAL | VM_ALLOC_RETRY); 813 if ((ma[0]->valid & VM_PAGE_BITS_ALL) != VM_PAGE_BITS_ALL) { 814 initial_pagein = VM_INITIAL_PAGEIN; 815 if (initial_pagein > object->size) 816 initial_pagein = object->size; 817 for (i = 1; i < initial_pagein; i++) { 818 if ((ma[i] = vm_page_lookup(object, i)) != NULL) { 819 if (ma[i]->valid) 820 break; 821 if ((ma[i]->flags & PG_BUSY) || ma[i]->busy) 822 break; 823 vm_page_lock_queues(); 824 vm_page_busy(ma[i]); 825 vm_page_unlock_queues(); 826 } else { 827 ma[i] = vm_page_alloc(object, i, 828 VM_ALLOC_NORMAL); 829 if (ma[i] == NULL) 830 break; 831 } 832 } 833 initial_pagein = i; 834 rv = vm_pager_get_pages(object, ma, initial_pagein, 0); 835 ma[0] = vm_page_lookup(object, 0); 836 if ((rv != VM_PAGER_OK) || (ma[0] == NULL) || 837 (ma[0]->valid == 0)) { 838 if (ma[0]) { 839 vm_page_lock_queues(); 840 vm_page_free(ma[0]); 841 vm_page_unlock_queues(); 842 } 843 VM_OBJECT_UNLOCK(object); 844 return (EIO); 845 } 846 } 847 vm_page_lock_queues(); 848 vm_page_hold(ma[0]); 849 vm_page_wakeup(ma[0]); 850 vm_page_unlock_queues(); 851 VM_OBJECT_UNLOCK(object); 852 853 imgp->firstpage = sf_buf_alloc(ma[0], 0); 854 imgp->image_header = (char *)sf_buf_kva(imgp->firstpage); 855 856 return (0); 857 } 858 859 void 860 exec_unmap_first_page(imgp) 861 struct image_params *imgp; 862 { 863 vm_page_t m; 864 865 if (imgp->firstpage != NULL) { 866 m = sf_buf_page(imgp->firstpage); 867 sf_buf_free(imgp->firstpage); 868 imgp->firstpage = NULL; 869 vm_page_lock_queues(); 870 vm_page_unhold(m); 871 vm_page_unlock_queues(); 872 } 873 } 874 875 /* 876 * Destroy old address space, and allocate a new stack 877 * The new stack is only SGROWSIZ large because it is grown 878 * automatically in trap.c. 879 */ 880 int 881 exec_new_vmspace(imgp, sv) 882 struct image_params *imgp; 883 struct sysentvec *sv; 884 { 885 int error; 886 struct proc *p = imgp->proc; 887 struct vmspace *vmspace = p->p_vmspace; 888 vm_offset_t stack_addr; 889 vm_map_t map; 890 891 imgp->vmspace_destroyed = 1; 892 893 /* Called with Giant held, do not depend on it! */ 894 EVENTHANDLER_INVOKE(process_exec, p); 895 896 /* 897 * Here is as good a place as any to do any resource limit cleanups. 898 * This is needed if a 64 bit binary exec's a 32 bit binary - the 899 * data size limit may need to be changed to a value that makes 900 * sense for the 32 bit binary. 901 */ 902 if (sv->sv_fixlimits != NULL) 903 sv->sv_fixlimits(p); 904 905 /* 906 * Blow away entire process VM, if address space not shared, 907 * otherwise, create a new VM space so that other threads are 908 * not disrupted 909 */ 910 map = &vmspace->vm_map; 911 if (vmspace->vm_refcnt == 1 && vm_map_min(map) == sv->sv_minuser && 912 vm_map_max(map) == sv->sv_maxuser) { 913 shmexit(vmspace); 914 pmap_remove_pages(vmspace_pmap(vmspace)); 915 vm_map_remove(map, vm_map_min(map), vm_map_max(map)); 916 } else { 917 vmspace_exec(p, sv->sv_minuser, sv->sv_maxuser); 918 vmspace = p->p_vmspace; 919 map = &vmspace->vm_map; 920 } 921 922 /* Allocate a new stack */ 923 stack_addr = sv->sv_usrstack - maxssiz; 924 error = vm_map_stack(map, stack_addr, (vm_size_t)maxssiz, 925 sv->sv_stackprot, VM_PROT_ALL, MAP_STACK_GROWS_DOWN); 926 if (error) 927 return (error); 928 929 #ifdef __ia64__ 930 /* Allocate a new register stack */ 931 stack_addr = IA64_BACKINGSTORE; 932 error = vm_map_stack(map, stack_addr, (vm_size_t)maxssiz, 933 sv->sv_stackprot, VM_PROT_ALL, MAP_STACK_GROWS_UP); 934 if (error) 935 return (error); 936 #endif 937 938 /* vm_ssize and vm_maxsaddr are somewhat antiquated concepts in the 939 * VM_STACK case, but they are still used to monitor the size of the 940 * process stack so we can check the stack rlimit. 941 */ 942 vmspace->vm_ssize = sgrowsiz >> PAGE_SHIFT; 943 vmspace->vm_maxsaddr = (char *)sv->sv_usrstack - maxssiz; 944 945 return (0); 946 } 947 948 /* 949 * Copy out argument and environment strings from the old process 950 * address space into the temporary string buffer. 951 */ 952 int 953 exec_copyin_args(struct image_args *args, char *fname, 954 enum uio_seg segflg, char **argv, char **envv) 955 { 956 char *argp, *envp; 957 int error; 958 size_t length; 959 960 error = 0; 961 962 bzero(args, sizeof(*args)); 963 if (argv == NULL) 964 return (EFAULT); 965 /* 966 * Allocate temporary demand zeroed space for argument and 967 * environment strings: 968 * 969 * o ARG_MAX for argument and environment; 970 * o MAXSHELLCMDLEN for the name of interpreters. 971 */ 972 args->buf = (char *) kmem_alloc_wait(exec_map, 973 PATH_MAX + ARG_MAX + MAXSHELLCMDLEN); 974 if (args->buf == NULL) 975 return (ENOMEM); 976 args->begin_argv = args->buf; 977 args->endp = args->begin_argv; 978 args->stringspace = ARG_MAX; 979 980 args->fname = args->buf + ARG_MAX; 981 982 /* 983 * Copy the file name. 984 */ 985 error = (segflg == UIO_SYSSPACE) ? 986 copystr(fname, args->fname, PATH_MAX, &length) : 987 copyinstr(fname, args->fname, PATH_MAX, &length); 988 if (error != 0) 989 goto err_exit; 990 991 /* 992 * extract arguments first 993 */ 994 while ((argp = (caddr_t) (intptr_t) fuword(argv++))) { 995 if (argp == (caddr_t) -1) { 996 error = EFAULT; 997 goto err_exit; 998 } 999 if ((error = copyinstr(argp, args->endp, 1000 args->stringspace, &length))) { 1001 if (error == ENAMETOOLONG) 1002 error = E2BIG; 1003 goto err_exit; 1004 } 1005 args->stringspace -= length; 1006 args->endp += length; 1007 args->argc++; 1008 } 1009 1010 args->begin_envv = args->endp; 1011 1012 /* 1013 * extract environment strings 1014 */ 1015 if (envv) { 1016 while ((envp = (caddr_t)(intptr_t)fuword(envv++))) { 1017 if (envp == (caddr_t)-1) { 1018 error = EFAULT; 1019 goto err_exit; 1020 } 1021 if ((error = copyinstr(envp, args->endp, 1022 args->stringspace, &length))) { 1023 if (error == ENAMETOOLONG) 1024 error = E2BIG; 1025 goto err_exit; 1026 } 1027 args->stringspace -= length; 1028 args->endp += length; 1029 args->envc++; 1030 } 1031 } 1032 1033 return (0); 1034 1035 err_exit: 1036 exec_free_args(args); 1037 return (error); 1038 } 1039 1040 static void 1041 exec_free_args(struct image_args *args) 1042 { 1043 1044 if (args->buf) { 1045 kmem_free_wakeup(exec_map, (vm_offset_t)args->buf, 1046 PATH_MAX + ARG_MAX + MAXSHELLCMDLEN); 1047 args->buf = NULL; 1048 } 1049 } 1050 1051 /* 1052 * Copy strings out to the new process address space, constructing 1053 * new arg and env vector tables. Return a pointer to the base 1054 * so that it can be used as the initial stack pointer. 1055 */ 1056 register_t * 1057 exec_copyout_strings(imgp) 1058 struct image_params *imgp; 1059 { 1060 int argc, envc; 1061 char **vectp; 1062 char *stringp, *destp; 1063 register_t *stack_base; 1064 struct ps_strings *arginfo; 1065 struct proc *p; 1066 int szsigcode; 1067 1068 /* 1069 * Calculate string base and vector table pointers. 1070 * Also deal with signal trampoline code for this exec type. 1071 */ 1072 p = imgp->proc; 1073 szsigcode = 0; 1074 arginfo = (struct ps_strings *)p->p_sysent->sv_psstrings; 1075 if (p->p_sysent->sv_szsigcode != NULL) 1076 szsigcode = *(p->p_sysent->sv_szsigcode); 1077 destp = (caddr_t)arginfo - szsigcode - SPARE_USRSPACE - 1078 roundup((ARG_MAX - imgp->args->stringspace), sizeof(char *)); 1079 1080 /* 1081 * install sigcode 1082 */ 1083 if (szsigcode) 1084 copyout(p->p_sysent->sv_sigcode, ((caddr_t)arginfo - 1085 szsigcode), szsigcode); 1086 1087 /* 1088 * If we have a valid auxargs ptr, prepare some room 1089 * on the stack. 1090 */ 1091 if (imgp->auxargs) { 1092 /* 1093 * 'AT_COUNT*2' is size for the ELF Auxargs data. This is for 1094 * lower compatibility. 1095 */ 1096 imgp->auxarg_size = (imgp->auxarg_size) ? imgp->auxarg_size : 1097 (AT_COUNT * 2); 1098 /* 1099 * The '+ 2' is for the null pointers at the end of each of 1100 * the arg and env vector sets,and imgp->auxarg_size is room 1101 * for argument of Runtime loader. 1102 */ 1103 vectp = (char **)(destp - (imgp->args->argc + 1104 imgp->args->envc + 2 + imgp->auxarg_size) * 1105 sizeof(char *)); 1106 1107 } else { 1108 /* 1109 * The '+ 2' is for the null pointers at the end of each of 1110 * the arg and env vector sets 1111 */ 1112 vectp = (char **)(destp - (imgp->args->argc + imgp->args->envc + 2) * 1113 sizeof(char *)); 1114 } 1115 1116 /* 1117 * vectp also becomes our initial stack base 1118 */ 1119 stack_base = (register_t *)vectp; 1120 1121 stringp = imgp->args->begin_argv; 1122 argc = imgp->args->argc; 1123 envc = imgp->args->envc; 1124 1125 /* 1126 * Copy out strings - arguments and environment. 1127 */ 1128 copyout(stringp, destp, ARG_MAX - imgp->args->stringspace); 1129 1130 /* 1131 * Fill in "ps_strings" struct for ps, w, etc. 1132 */ 1133 suword(&arginfo->ps_argvstr, (long)(intptr_t)vectp); 1134 suword(&arginfo->ps_nargvstr, argc); 1135 1136 /* 1137 * Fill in argument portion of vector table. 1138 */ 1139 for (; argc > 0; --argc) { 1140 suword(vectp++, (long)(intptr_t)destp); 1141 while (*stringp++ != 0) 1142 destp++; 1143 destp++; 1144 } 1145 1146 /* a null vector table pointer separates the argp's from the envp's */ 1147 suword(vectp++, 0); 1148 1149 suword(&arginfo->ps_envstr, (long)(intptr_t)vectp); 1150 suword(&arginfo->ps_nenvstr, envc); 1151 1152 /* 1153 * Fill in environment portion of vector table. 1154 */ 1155 for (; envc > 0; --envc) { 1156 suword(vectp++, (long)(intptr_t)destp); 1157 while (*stringp++ != 0) 1158 destp++; 1159 destp++; 1160 } 1161 1162 /* end of vector table is a null pointer */ 1163 suword(vectp, 0); 1164 1165 return (stack_base); 1166 } 1167 1168 /* 1169 * Check permissions of file to execute. 1170 * Called with imgp->vp locked. 1171 * Return 0 for success or error code on failure. 1172 */ 1173 int 1174 exec_check_permissions(imgp) 1175 struct image_params *imgp; 1176 { 1177 struct vnode *vp = imgp->vp; 1178 struct vattr *attr = imgp->attr; 1179 struct thread *td; 1180 int error; 1181 1182 td = curthread; /* XXXKSE */ 1183 1184 /* Get file attributes */ 1185 error = VOP_GETATTR(vp, attr, td->td_ucred, td); 1186 if (error) 1187 return (error); 1188 1189 #ifdef MAC 1190 error = mac_check_vnode_exec(td->td_ucred, imgp->vp, imgp); 1191 if (error) 1192 return (error); 1193 #endif 1194 1195 /* 1196 * 1) Check if file execution is disabled for the filesystem that this 1197 * file resides on. 1198 * 2) Insure that at least one execute bit is on - otherwise root 1199 * will always succeed, and we don't want to happen unless the 1200 * file really is executable. 1201 * 3) Insure that the file is a regular file. 1202 */ 1203 if ((vp->v_mount->mnt_flag & MNT_NOEXEC) || 1204 ((attr->va_mode & 0111) == 0) || 1205 (attr->va_type != VREG)) 1206 return (EACCES); 1207 1208 /* 1209 * Zero length files can't be exec'd 1210 */ 1211 if (attr->va_size == 0) 1212 return (ENOEXEC); 1213 1214 /* 1215 * Check for execute permission to file based on current credentials. 1216 */ 1217 error = VOP_ACCESS(vp, VEXEC, td->td_ucred, td); 1218 if (error) 1219 return (error); 1220 1221 /* 1222 * Check number of open-for-writes on the file and deny execution 1223 * if there are any. 1224 */ 1225 if (vp->v_writecount) 1226 return (ETXTBSY); 1227 1228 /* 1229 * Call filesystem specific open routine (which does nothing in the 1230 * general case). 1231 */ 1232 error = VOP_OPEN(vp, FREAD, td->td_ucred, td, -1); 1233 return (error); 1234 } 1235 1236 /* 1237 * Exec handler registration 1238 */ 1239 int 1240 exec_register(execsw_arg) 1241 const struct execsw *execsw_arg; 1242 { 1243 const struct execsw **es, **xs, **newexecsw; 1244 int count = 2; /* New slot and trailing NULL */ 1245 1246 if (execsw) 1247 for (es = execsw; *es; es++) 1248 count++; 1249 newexecsw = malloc(count * sizeof(*es), M_TEMP, M_WAITOK); 1250 if (newexecsw == NULL) 1251 return (ENOMEM); 1252 xs = newexecsw; 1253 if (execsw) 1254 for (es = execsw; *es; es++) 1255 *xs++ = *es; 1256 *xs++ = execsw_arg; 1257 *xs = NULL; 1258 if (execsw) 1259 free(execsw, M_TEMP); 1260 execsw = newexecsw; 1261 return (0); 1262 } 1263 1264 int 1265 exec_unregister(execsw_arg) 1266 const struct execsw *execsw_arg; 1267 { 1268 const struct execsw **es, **xs, **newexecsw; 1269 int count = 1; 1270 1271 if (execsw == NULL) 1272 panic("unregister with no handlers left?\n"); 1273 1274 for (es = execsw; *es; es++) { 1275 if (*es == execsw_arg) 1276 break; 1277 } 1278 if (*es == NULL) 1279 return (ENOENT); 1280 for (es = execsw; *es; es++) 1281 if (*es != execsw_arg) 1282 count++; 1283 newexecsw = malloc(count * sizeof(*es), M_TEMP, M_WAITOK); 1284 if (newexecsw == NULL) 1285 return (ENOMEM); 1286 xs = newexecsw; 1287 for (es = execsw; *es; es++) 1288 if (*es != execsw_arg) 1289 *xs++ = *es; 1290 *xs = NULL; 1291 if (execsw) 1292 free(execsw, M_TEMP); 1293 execsw = newexecsw; 1294 return (0); 1295 } 1296