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/mount.h> 43 #include <sys/filedesc.h> 44 #include <sys/fcntl.h> 45 #include <sys/acct.h> 46 #include <sys/exec.h> 47 #include <sys/imgact.h> 48 #include <sys/imgact_elf.h> 49 #include <sys/wait.h> 50 #include <sys/malloc.h> 51 #include <sys/priv.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 #include <security/audit/audit.h> 83 #include <security/mac/mac_framework.h> 84 85 MALLOC_DEFINE(M_PARGS, "proc-args", "Process arguments"); 86 87 static int sysctl_kern_ps_strings(SYSCTL_HANDLER_ARGS); 88 static int sysctl_kern_usrstack(SYSCTL_HANDLER_ARGS); 89 static int sysctl_kern_stackprot(SYSCTL_HANDLER_ARGS); 90 static int do_execve(struct thread *td, struct image_args *args, 91 struct mac *mac_p); 92 static void exec_free_args(struct image_args *); 93 94 /* XXX This should be vm_size_t. */ 95 SYSCTL_PROC(_kern, KERN_PS_STRINGS, ps_strings, CTLTYPE_ULONG|CTLFLAG_RD, 96 NULL, 0, sysctl_kern_ps_strings, "LU", ""); 97 98 /* XXX This should be vm_size_t. */ 99 SYSCTL_PROC(_kern, KERN_USRSTACK, usrstack, CTLTYPE_ULONG|CTLFLAG_RD, 100 NULL, 0, sysctl_kern_usrstack, "LU", ""); 101 102 SYSCTL_PROC(_kern, OID_AUTO, stackprot, CTLTYPE_INT|CTLFLAG_RD, 103 NULL, 0, sysctl_kern_stackprot, "I", ""); 104 105 u_long ps_arg_cache_limit = PAGE_SIZE / 16; 106 SYSCTL_ULONG(_kern, OID_AUTO, ps_arg_cache_limit, CTLFLAG_RW, 107 &ps_arg_cache_limit, 0, ""); 108 109 static int 110 sysctl_kern_ps_strings(SYSCTL_HANDLER_ARGS) 111 { 112 struct proc *p; 113 int error; 114 115 p = curproc; 116 #ifdef SCTL_MASK32 117 if (req->flags & SCTL_MASK32) { 118 unsigned int val; 119 val = (unsigned int)p->p_sysent->sv_psstrings; 120 error = SYSCTL_OUT(req, &val, sizeof(val)); 121 } else 122 #endif 123 error = SYSCTL_OUT(req, &p->p_sysent->sv_psstrings, 124 sizeof(p->p_sysent->sv_psstrings)); 125 return error; 126 } 127 128 static int 129 sysctl_kern_usrstack(SYSCTL_HANDLER_ARGS) 130 { 131 struct proc *p; 132 int error; 133 134 p = curproc; 135 #ifdef SCTL_MASK32 136 if (req->flags & SCTL_MASK32) { 137 unsigned int val; 138 val = (unsigned int)p->p_sysent->sv_usrstack; 139 error = SYSCTL_OUT(req, &val, sizeof(val)); 140 } else 141 #endif 142 error = SYSCTL_OUT(req, &p->p_sysent->sv_usrstack, 143 sizeof(p->p_sysent->sv_usrstack)); 144 return error; 145 } 146 147 static int 148 sysctl_kern_stackprot(SYSCTL_HANDLER_ARGS) 149 { 150 struct proc *p; 151 152 p = curproc; 153 return (SYSCTL_OUT(req, &p->p_sysent->sv_stackprot, 154 sizeof(p->p_sysent->sv_stackprot))); 155 } 156 157 /* 158 * Each of the items is a pointer to a `const struct execsw', hence the 159 * double pointer here. 160 */ 161 static const struct execsw **execsw; 162 163 #ifndef _SYS_SYSPROTO_H_ 164 struct execve_args { 165 char *fname; 166 char **argv; 167 char **envv; 168 }; 169 #endif 170 171 /* 172 * MPSAFE 173 */ 174 int 175 execve(td, uap) 176 struct thread *td; 177 struct execve_args /* { 178 char *fname; 179 char **argv; 180 char **envv; 181 } */ *uap; 182 { 183 int error; 184 struct image_args args; 185 186 error = exec_copyin_args(&args, uap->fname, UIO_USERSPACE, 187 uap->argv, uap->envv); 188 if (error == 0) 189 error = kern_execve(td, &args, NULL); 190 return (error); 191 } 192 193 #ifndef _SYS_SYSPROTO_H_ 194 struct __mac_execve_args { 195 char *fname; 196 char **argv; 197 char **envv; 198 struct mac *mac_p; 199 }; 200 #endif 201 202 /* 203 * MPSAFE 204 */ 205 int 206 __mac_execve(td, uap) 207 struct thread *td; 208 struct __mac_execve_args /* { 209 char *fname; 210 char **argv; 211 char **envv; 212 struct mac *mac_p; 213 } */ *uap; 214 { 215 #ifdef MAC 216 int error; 217 struct image_args args; 218 219 error = exec_copyin_args(&args, uap->fname, UIO_USERSPACE, 220 uap->argv, uap->envv); 221 if (error == 0) 222 error = kern_execve(td, &args, uap->mac_p); 223 return (error); 224 #else 225 return (ENOSYS); 226 #endif 227 } 228 229 /* 230 * XXX: kern_execve has the astonishing property of not always 231 * returning to the caller. If sufficiently bad things happen during 232 * the call to do_execve(), it can end up calling exit1(); as a result, 233 * callers must avoid doing anything which they might need to undo 234 * (e.g., allocating memory). 235 */ 236 int 237 kern_execve(td, args, mac_p) 238 struct thread *td; 239 struct image_args *args; 240 struct mac *mac_p; 241 { 242 struct proc *p = td->td_proc; 243 int error; 244 245 AUDIT_ARG(argv, args->begin_argv, args->argc, 246 args->begin_envv - args->begin_argv); 247 AUDIT_ARG(envv, args->begin_envv, args->envc, 248 args->endp - args->begin_envv); 249 if (p->p_flag & P_HADTHREADS) { 250 PROC_LOCK(p); 251 if (thread_single(SINGLE_BOUNDARY)) { 252 PROC_UNLOCK(p); 253 exec_free_args(args); 254 return (ERESTART); /* Try again later. */ 255 } 256 PROC_UNLOCK(p); 257 } 258 259 error = do_execve(td, args, mac_p); 260 261 if (p->p_flag & P_HADTHREADS) { 262 PROC_LOCK(p); 263 /* 264 * If success, we upgrade to SINGLE_EXIT state to 265 * force other threads to suicide. 266 */ 267 if (error == 0) 268 thread_single(SINGLE_EXIT); 269 else 270 thread_single_end(); 271 PROC_UNLOCK(p); 272 } 273 274 return (error); 275 } 276 277 /* 278 * In-kernel implementation of execve(). All arguments are assumed to be 279 * userspace pointers from the passed thread. 280 * 281 * MPSAFE 282 */ 283 static int 284 do_execve(td, args, mac_p) 285 struct thread *td; 286 struct image_args *args; 287 struct mac *mac_p; 288 { 289 struct proc *p = td->td_proc; 290 struct nameidata nd, *ndp; 291 struct ucred *newcred = NULL, *oldcred; 292 struct uidinfo *euip; 293 register_t *stack_base; 294 int error, len, i; 295 struct image_params image_params, *imgp; 296 struct vattr attr; 297 int (*img_first)(struct image_params *); 298 struct pargs *oldargs = NULL, *newargs = NULL; 299 struct sigacts *oldsigacts, *newsigacts; 300 #ifdef KTRACE 301 struct vnode *tracevp = NULL; 302 struct ucred *tracecred = NULL; 303 #endif 304 struct vnode *textvp = NULL; 305 int credential_changing; 306 int vfslocked; 307 int textset; 308 #ifdef MAC 309 struct label *interplabel = NULL; 310 int will_transition; 311 #endif 312 #ifdef HWPMC_HOOKS 313 struct pmckern_procexec pe; 314 #endif 315 316 vfslocked = 0; 317 imgp = &image_params; 318 319 /* 320 * Lock the process and set the P_INEXEC flag to indicate that 321 * it should be left alone until we're done here. This is 322 * necessary to avoid race conditions - e.g. in ptrace() - 323 * that might allow a local user to illicitly obtain elevated 324 * privileges. 325 */ 326 PROC_LOCK(p); 327 KASSERT((p->p_flag & P_INEXEC) == 0, 328 ("%s(): process already has P_INEXEC flag", __func__)); 329 p->p_flag |= P_INEXEC; 330 PROC_UNLOCK(p); 331 332 /* 333 * Initialize part of the common data 334 */ 335 imgp->proc = p; 336 imgp->execlabel = NULL; 337 imgp->attr = &attr; 338 imgp->entry_addr = 0; 339 imgp->vmspace_destroyed = 0; 340 imgp->interpreted = 0; 341 imgp->interpreter_name = args->buf + PATH_MAX + ARG_MAX; 342 imgp->auxargs = NULL; 343 imgp->vp = NULL; 344 imgp->object = NULL; 345 imgp->firstpage = NULL; 346 imgp->ps_strings = 0; 347 imgp->auxarg_size = 0; 348 imgp->args = args; 349 350 #ifdef MAC 351 error = mac_execve_enter(imgp, mac_p); 352 if (error) 353 goto exec_fail; 354 #endif 355 356 imgp->image_header = NULL; 357 358 /* 359 * Translate the file name. namei() returns a vnode pointer 360 * in ni_vp amoung other things. 361 * 362 * XXXAUDIT: It would be desirable to also audit the name of the 363 * interpreter if this is an interpreted binary. 364 */ 365 ndp = &nd; 366 NDINIT(ndp, LOOKUP, ISOPEN | LOCKLEAF | FOLLOW | SAVENAME | MPSAFE | 367 AUDITVNODE1, UIO_SYSSPACE, args->fname, td); 368 369 interpret: 370 error = namei(ndp); 371 if (error) 372 goto exec_fail; 373 374 vfslocked = NDHASGIANT(ndp); 375 imgp->vp = ndp->ni_vp; 376 377 /* 378 * Check file permissions (also 'opens' file) 379 */ 380 error = exec_check_permissions(imgp); 381 if (error) 382 goto exec_fail_dealloc; 383 384 imgp->object = imgp->vp->v_object; 385 if (imgp->object != NULL) 386 vm_object_reference(imgp->object); 387 388 /* 389 * Set VV_TEXT now so no one can write to the executable while we're 390 * activating it. 391 * 392 * Remember if this was set before and unset it in case this is not 393 * actually an executable image. 394 */ 395 textset = imgp->vp->v_vflag & VV_TEXT; 396 imgp->vp->v_vflag |= VV_TEXT; 397 398 error = exec_map_first_page(imgp); 399 if (error) 400 goto exec_fail_dealloc; 401 402 /* 403 * If the current process has a special image activator it 404 * wants to try first, call it. For example, emulating shell 405 * scripts differently. 406 */ 407 error = -1; 408 if ((img_first = imgp->proc->p_sysent->sv_imgact_try) != NULL) 409 error = img_first(imgp); 410 411 /* 412 * Loop through the list of image activators, calling each one. 413 * An activator returns -1 if there is no match, 0 on success, 414 * and an error otherwise. 415 */ 416 for (i = 0; error == -1 && execsw[i]; ++i) { 417 if (execsw[i]->ex_imgact == NULL || 418 execsw[i]->ex_imgact == img_first) { 419 continue; 420 } 421 error = (*execsw[i]->ex_imgact)(imgp); 422 } 423 424 if (error) { 425 if (error == -1) { 426 if (textset == 0) 427 imgp->vp->v_vflag &= ~VV_TEXT; 428 error = ENOEXEC; 429 } 430 goto exec_fail_dealloc; 431 } 432 433 /* 434 * Special interpreter operation, cleanup and loop up to try to 435 * activate the interpreter. 436 */ 437 if (imgp->interpreted) { 438 exec_unmap_first_page(imgp); 439 /* 440 * VV_TEXT needs to be unset for scripts. There is a short 441 * period before we determine that something is a script where 442 * VV_TEXT will be set. The vnode lock is held over this 443 * entire period so nothing should illegitimately be blocked. 444 */ 445 imgp->vp->v_vflag &= ~VV_TEXT; 446 /* free name buffer and old vnode */ 447 NDFREE(ndp, NDF_ONLY_PNBUF); 448 #ifdef MAC 449 interplabel = mac_vnode_label_alloc(); 450 mac_copy_vnode_label(ndp->ni_vp->v_label, interplabel); 451 #endif 452 vput(ndp->ni_vp); 453 vm_object_deallocate(imgp->object); 454 imgp->object = NULL; 455 VFS_UNLOCK_GIANT(vfslocked); 456 vfslocked = 0; 457 /* set new name to that of the interpreter */ 458 NDINIT(ndp, LOOKUP, LOCKLEAF | FOLLOW | SAVENAME | MPSAFE, 459 UIO_SYSSPACE, imgp->interpreter_name, td); 460 goto interpret; 461 } 462 463 /* 464 * Copy out strings (args and env) and initialize stack base 465 */ 466 if (p->p_sysent->sv_copyout_strings) 467 stack_base = (*p->p_sysent->sv_copyout_strings)(imgp); 468 else 469 stack_base = exec_copyout_strings(imgp); 470 471 /* 472 * If custom stack fixup routine present for this process 473 * let it do the stack setup. 474 * Else stuff argument count as first item on stack 475 */ 476 if (p->p_sysent->sv_fixup != NULL) 477 (*p->p_sysent->sv_fixup)(&stack_base, imgp); 478 else 479 suword(--stack_base, imgp->args->argc); 480 481 /* 482 * For security and other reasons, the file descriptor table cannot 483 * be shared after an exec. 484 */ 485 fdunshare(p, td); 486 487 /* 488 * Malloc things before we need locks. 489 */ 490 newcred = crget(); 491 euip = uifind(attr.va_uid); 492 i = imgp->args->begin_envv - imgp->args->begin_argv; 493 /* Cache arguments if they fit inside our allowance */ 494 if (ps_arg_cache_limit >= i + sizeof(struct pargs)) { 495 newargs = pargs_alloc(i); 496 bcopy(imgp->args->begin_argv, newargs->ar_args, i); 497 } 498 499 /* close files on exec */ 500 VOP_UNLOCK(imgp->vp, 0, td); 501 fdcloseexec(td); 502 vn_lock(imgp->vp, LK_EXCLUSIVE | LK_RETRY, td); 503 504 /* Get a reference to the vnode prior to locking the proc */ 505 VREF(ndp->ni_vp); 506 507 /* 508 * For security and other reasons, signal handlers cannot 509 * be shared after an exec. The new process gets a copy of the old 510 * handlers. In execsigs(), the new process will have its signals 511 * reset. 512 */ 513 PROC_LOCK(p); 514 if (sigacts_shared(p->p_sigacts)) { 515 oldsigacts = p->p_sigacts; 516 PROC_UNLOCK(p); 517 newsigacts = sigacts_alloc(); 518 sigacts_copy(newsigacts, oldsigacts); 519 PROC_LOCK(p); 520 p->p_sigacts = newsigacts; 521 } else 522 oldsigacts = NULL; 523 524 /* Stop profiling */ 525 stopprofclock(p); 526 527 /* reset caught signals */ 528 execsigs(p); 529 530 /* name this process - nameiexec(p, ndp) */ 531 len = min(ndp->ni_cnd.cn_namelen,MAXCOMLEN); 532 bcopy(ndp->ni_cnd.cn_nameptr, p->p_comm, len); 533 p->p_comm[len] = 0; 534 535 /* 536 * mark as execed, wakeup the process that vforked (if any) and tell 537 * it that it now has its own resources back 538 */ 539 p->p_flag |= P_EXEC; 540 if (p->p_pptr && (p->p_flag & P_PPWAIT)) { 541 p->p_flag &= ~P_PPWAIT; 542 wakeup(p->p_pptr); 543 } 544 545 /* 546 * Implement image setuid/setgid. 547 * 548 * Don't honor setuid/setgid if the filesystem prohibits it or if 549 * the process is being traced. 550 * 551 * XXXMAC: For the time being, use NOSUID to also prohibit 552 * transitions on the file system. 553 */ 554 oldcred = p->p_ucred; 555 credential_changing = 0; 556 credential_changing |= (attr.va_mode & VSUID) && oldcred->cr_uid != 557 attr.va_uid; 558 credential_changing |= (attr.va_mode & VSGID) && oldcred->cr_gid != 559 attr.va_gid; 560 #ifdef MAC 561 will_transition = mac_execve_will_transition(oldcred, imgp->vp, 562 interplabel, imgp); 563 credential_changing |= will_transition; 564 #endif 565 566 if (credential_changing && 567 (imgp->vp->v_mount->mnt_flag & MNT_NOSUID) == 0 && 568 (p->p_flag & P_TRACED) == 0) { 569 /* 570 * Turn off syscall tracing for set-id programs, except for 571 * root. Record any set-id flags first to make sure that 572 * we do not regain any tracing during a possible block. 573 */ 574 setsugid(p); 575 576 #ifdef KTRACE 577 if (p->p_tracevp != NULL && 578 priv_check_cred(oldcred, PRIV_DEBUG_DIFFCRED, 579 SUSER_ALLOWJAIL)) { 580 mtx_lock(&ktrace_mtx); 581 p->p_traceflag = 0; 582 tracevp = p->p_tracevp; 583 p->p_tracevp = NULL; 584 tracecred = p->p_tracecred; 585 p->p_tracecred = NULL; 586 mtx_unlock(&ktrace_mtx); 587 } 588 #endif 589 /* 590 * Close any file descriptors 0..2 that reference procfs, 591 * then make sure file descriptors 0..2 are in use. 592 * 593 * setugidsafety() may call closef() and then pfind() 594 * which may grab the process lock. 595 * fdcheckstd() may call falloc() which may block to 596 * allocate memory, so temporarily drop the process lock. 597 */ 598 PROC_UNLOCK(p); 599 setugidsafety(td); 600 VOP_UNLOCK(imgp->vp, 0, td); 601 error = fdcheckstd(td); 602 vn_lock(imgp->vp, LK_EXCLUSIVE | LK_RETRY, td); 603 if (error != 0) 604 goto done1; 605 PROC_LOCK(p); 606 /* 607 * Set the new credentials. 608 */ 609 crcopy(newcred, oldcred); 610 if (attr.va_mode & VSUID) 611 change_euid(newcred, euip); 612 if (attr.va_mode & VSGID) 613 change_egid(newcred, attr.va_gid); 614 #ifdef MAC 615 if (will_transition) { 616 mac_execve_transition(oldcred, newcred, imgp->vp, 617 interplabel, imgp); 618 } 619 #endif 620 /* 621 * Implement correct POSIX saved-id behavior. 622 * 623 * XXXMAC: Note that the current logic will save the 624 * uid and gid if a MAC domain transition occurs, even 625 * though maybe it shouldn't. 626 */ 627 change_svuid(newcred, newcred->cr_uid); 628 change_svgid(newcred, newcred->cr_gid); 629 p->p_ucred = newcred; 630 newcred = NULL; 631 } else { 632 if (oldcred->cr_uid == oldcred->cr_ruid && 633 oldcred->cr_gid == oldcred->cr_rgid) 634 p->p_flag &= ~P_SUGID; 635 /* 636 * Implement correct POSIX saved-id behavior. 637 * 638 * XXX: It's not clear that the existing behavior is 639 * POSIX-compliant. A number of sources indicate that the 640 * saved uid/gid should only be updated if the new ruid is 641 * not equal to the old ruid, or the new euid is not equal 642 * to the old euid and the new euid is not equal to the old 643 * ruid. The FreeBSD code always updates the saved uid/gid. 644 * Also, this code uses the new (replaced) euid and egid as 645 * the source, which may or may not be the right ones to use. 646 */ 647 if (oldcred->cr_svuid != oldcred->cr_uid || 648 oldcred->cr_svgid != oldcred->cr_gid) { 649 crcopy(newcred, oldcred); 650 change_svuid(newcred, newcred->cr_uid); 651 change_svgid(newcred, newcred->cr_gid); 652 p->p_ucred = newcred; 653 newcred = NULL; 654 } 655 } 656 657 /* 658 * Store the vp for use in procfs. This vnode was referenced prior 659 * to locking the proc lock. 660 */ 661 textvp = p->p_textvp; 662 p->p_textvp = ndp->ni_vp; 663 664 /* 665 * Notify others that we exec'd, and clear the P_INEXEC flag 666 * as we're now a bona fide freshly-execed process. 667 */ 668 KNOTE_LOCKED(&p->p_klist, NOTE_EXEC); 669 p->p_flag &= ~P_INEXEC; 670 671 /* 672 * If tracing the process, trap to debugger so breakpoints 673 * can be set before the program executes. 674 * Use tdsignal to deliver signal to current thread, use 675 * psignal may cause the signal to be delivered to wrong thread 676 * because that thread will exit, remember we are going to enter 677 * single thread mode. 678 */ 679 if (p->p_flag & P_TRACED) 680 tdsignal(p, td, SIGTRAP, NULL); 681 682 /* clear "fork but no exec" flag, as we _are_ execing */ 683 p->p_acflag &= ~AFORK; 684 685 /* 686 * Free any previous argument cache and replace it with 687 * the new argument cache, if any. 688 */ 689 oldargs = p->p_args; 690 p->p_args = newargs; 691 newargs = NULL; 692 693 #ifdef HWPMC_HOOKS 694 /* 695 * Check if system-wide sampling is in effect or if the 696 * current process is using PMCs. If so, do exec() time 697 * processing. This processing needs to happen AFTER the 698 * P_INEXEC flag is cleared. 699 * 700 * The proc lock needs to be released before taking the PMC 701 * SX. 702 */ 703 if (PMC_SYSTEM_SAMPLING_ACTIVE() || PMC_PROC_IS_USING_PMCS(p)) { 704 PROC_UNLOCK(p); 705 pe.pm_credentialschanged = credential_changing; 706 pe.pm_entryaddr = imgp->entry_addr; 707 708 PMC_CALL_HOOK_X(td, PMC_FN_PROCESS_EXEC, (void *) &pe); 709 } else 710 PROC_UNLOCK(p); 711 #else /* !HWPMC_HOOKS */ 712 PROC_UNLOCK(p); 713 #endif 714 715 /* Set values passed into the program in registers. */ 716 if (p->p_sysent->sv_setregs) 717 (*p->p_sysent->sv_setregs)(td, imgp->entry_addr, 718 (u_long)(uintptr_t)stack_base, imgp->ps_strings); 719 else 720 exec_setregs(td, imgp->entry_addr, 721 (u_long)(uintptr_t)stack_base, imgp->ps_strings); 722 723 vfs_mark_atime(imgp->vp, td); 724 725 done1: 726 /* 727 * Free any resources malloc'd earlier that we didn't use. 728 */ 729 uifree(euip); 730 if (newcred == NULL) 731 crfree(oldcred); 732 else 733 crfree(newcred); 734 VOP_UNLOCK(imgp->vp, 0, td); 735 /* 736 * Handle deferred decrement of ref counts. 737 */ 738 if (textvp != NULL) { 739 int tvfslocked; 740 741 tvfslocked = VFS_LOCK_GIANT(textvp->v_mount); 742 vrele(textvp); 743 VFS_UNLOCK_GIANT(tvfslocked); 744 } 745 if (ndp->ni_vp && error != 0) 746 vrele(ndp->ni_vp); 747 #ifdef KTRACE 748 if (tracevp != NULL) 749 vrele(tracevp); 750 if (tracecred != NULL) 751 crfree(tracecred); 752 #endif 753 vn_lock(imgp->vp, LK_EXCLUSIVE | LK_RETRY, td); 754 if (oldargs != NULL) 755 pargs_drop(oldargs); 756 if (newargs != NULL) 757 pargs_drop(newargs); 758 if (oldsigacts != NULL) 759 sigacts_free(oldsigacts); 760 761 exec_fail_dealloc: 762 763 /* 764 * free various allocated resources 765 */ 766 if (imgp->firstpage != NULL) 767 exec_unmap_first_page(imgp); 768 769 if (imgp->vp != NULL) { 770 NDFREE(ndp, NDF_ONLY_PNBUF); 771 vput(imgp->vp); 772 } 773 774 if (imgp->object != NULL) 775 vm_object_deallocate(imgp->object); 776 777 if (error == 0) { 778 /* 779 * Stop the process here if its stop event mask has 780 * the S_EXEC bit set. 781 */ 782 STOPEVENT(p, S_EXEC, 0); 783 goto done2; 784 } 785 786 exec_fail: 787 /* we're done here, clear P_INEXEC */ 788 PROC_LOCK(p); 789 p->p_flag &= ~P_INEXEC; 790 PROC_UNLOCK(p); 791 792 done2: 793 #ifdef MAC 794 mac_execve_exit(imgp); 795 if (interplabel != NULL) 796 mac_vnode_label_free(interplabel); 797 #endif 798 VFS_UNLOCK_GIANT(vfslocked); 799 exec_free_args(args); 800 801 if (error && imgp->vmspace_destroyed) { 802 /* sorry, no more process anymore. exit gracefully */ 803 exit1(td, W_EXITCODE(0, SIGABRT)); 804 /* NOT REACHED */ 805 } 806 return (error); 807 } 808 809 int 810 exec_map_first_page(imgp) 811 struct image_params *imgp; 812 { 813 int rv, i; 814 int initial_pagein; 815 vm_page_t ma[VM_INITIAL_PAGEIN]; 816 vm_object_t object; 817 818 if (imgp->firstpage != NULL) 819 exec_unmap_first_page(imgp); 820 821 object = imgp->vp->v_object; 822 if (object == NULL) 823 return (EACCES); 824 VM_OBJECT_LOCK(object); 825 ma[0] = vm_page_grab(object, 0, VM_ALLOC_NORMAL | VM_ALLOC_RETRY); 826 if ((ma[0]->valid & VM_PAGE_BITS_ALL) != VM_PAGE_BITS_ALL) { 827 initial_pagein = VM_INITIAL_PAGEIN; 828 if (initial_pagein > object->size) 829 initial_pagein = object->size; 830 for (i = 1; i < initial_pagein; i++) { 831 if ((ma[i] = vm_page_lookup(object, i)) != NULL) { 832 if (ma[i]->valid) 833 break; 834 if ((ma[i]->oflags & VPO_BUSY) || ma[i]->busy) 835 break; 836 vm_page_busy(ma[i]); 837 } else { 838 ma[i] = vm_page_alloc(object, i, 839 VM_ALLOC_NORMAL); 840 if (ma[i] == NULL) 841 break; 842 } 843 } 844 initial_pagein = i; 845 rv = vm_pager_get_pages(object, ma, initial_pagein, 0); 846 ma[0] = vm_page_lookup(object, 0); 847 if ((rv != VM_PAGER_OK) || (ma[0] == NULL) || 848 (ma[0]->valid == 0)) { 849 if (ma[0]) { 850 vm_page_lock_queues(); 851 vm_page_free(ma[0]); 852 vm_page_unlock_queues(); 853 } 854 VM_OBJECT_UNLOCK(object); 855 return (EIO); 856 } 857 } 858 vm_page_lock_queues(); 859 vm_page_hold(ma[0]); 860 vm_page_unlock_queues(); 861 vm_page_wakeup(ma[0]); 862 VM_OBJECT_UNLOCK(object); 863 864 imgp->firstpage = sf_buf_alloc(ma[0], 0); 865 imgp->image_header = (char *)sf_buf_kva(imgp->firstpage); 866 867 return (0); 868 } 869 870 void 871 exec_unmap_first_page(imgp) 872 struct image_params *imgp; 873 { 874 vm_page_t m; 875 876 if (imgp->firstpage != NULL) { 877 m = sf_buf_page(imgp->firstpage); 878 sf_buf_free(imgp->firstpage); 879 imgp->firstpage = NULL; 880 vm_page_lock_queues(); 881 vm_page_unhold(m); 882 vm_page_unlock_queues(); 883 } 884 } 885 886 /* 887 * Destroy old address space, and allocate a new stack 888 * The new stack is only SGROWSIZ large because it is grown 889 * automatically in trap.c. 890 */ 891 int 892 exec_new_vmspace(imgp, sv) 893 struct image_params *imgp; 894 struct sysentvec *sv; 895 { 896 int error; 897 struct proc *p = imgp->proc; 898 struct vmspace *vmspace = p->p_vmspace; 899 vm_offset_t stack_addr; 900 vm_map_t map; 901 902 imgp->vmspace_destroyed = 1; 903 imgp->sysent = sv; 904 905 /* Called with Giant held, do not depend on it! */ 906 EVENTHANDLER_INVOKE(process_exec, p, imgp); 907 908 /* 909 * Here is as good a place as any to do any resource limit cleanups. 910 * This is needed if a 64 bit binary exec's a 32 bit binary - the 911 * data size limit may need to be changed to a value that makes 912 * sense for the 32 bit binary. 913 */ 914 if (sv->sv_fixlimits != NULL) 915 sv->sv_fixlimits(p); 916 917 /* 918 * Blow away entire process VM, if address space not shared, 919 * otherwise, create a new VM space so that other threads are 920 * not disrupted 921 */ 922 map = &vmspace->vm_map; 923 if (vmspace->vm_refcnt == 1 && vm_map_min(map) == sv->sv_minuser && 924 vm_map_max(map) == sv->sv_maxuser) { 925 shmexit(vmspace); 926 pmap_remove_pages(vmspace_pmap(vmspace)); 927 vm_map_remove(map, vm_map_min(map), vm_map_max(map)); 928 } else { 929 vmspace_exec(p, sv->sv_minuser, sv->sv_maxuser); 930 vmspace = p->p_vmspace; 931 map = &vmspace->vm_map; 932 } 933 934 /* Allocate a new stack */ 935 stack_addr = sv->sv_usrstack - maxssiz; 936 error = vm_map_stack(map, stack_addr, (vm_size_t)maxssiz, 937 sv->sv_stackprot, VM_PROT_ALL, MAP_STACK_GROWS_DOWN); 938 if (error) 939 return (error); 940 941 #ifdef __ia64__ 942 /* Allocate a new register stack */ 943 stack_addr = IA64_BACKINGSTORE; 944 error = vm_map_stack(map, stack_addr, (vm_size_t)maxssiz, 945 sv->sv_stackprot, VM_PROT_ALL, MAP_STACK_GROWS_UP); 946 if (error) 947 return (error); 948 #endif 949 950 /* vm_ssize and vm_maxsaddr are somewhat antiquated concepts in the 951 * VM_STACK case, but they are still used to monitor the size of the 952 * process stack so we can check the stack rlimit. 953 */ 954 vmspace->vm_ssize = sgrowsiz >> PAGE_SHIFT; 955 vmspace->vm_maxsaddr = (char *)sv->sv_usrstack - maxssiz; 956 957 return (0); 958 } 959 960 /* 961 * Copy out argument and environment strings from the old process 962 * address space into the temporary string buffer. 963 */ 964 int 965 exec_copyin_args(struct image_args *args, char *fname, 966 enum uio_seg segflg, char **argv, char **envv) 967 { 968 char *argp, *envp; 969 int error; 970 size_t length; 971 972 error = 0; 973 974 bzero(args, sizeof(*args)); 975 if (argv == NULL) 976 return (EFAULT); 977 /* 978 * Allocate temporary demand zeroed space for argument and 979 * environment strings: 980 * 981 * o ARG_MAX for argument and environment; 982 * o MAXSHELLCMDLEN for the name of interpreters. 983 */ 984 args->buf = (char *) kmem_alloc_wait(exec_map, 985 PATH_MAX + ARG_MAX + MAXSHELLCMDLEN); 986 if (args->buf == NULL) 987 return (ENOMEM); 988 args->begin_argv = args->buf; 989 args->endp = args->begin_argv; 990 args->stringspace = ARG_MAX; 991 992 args->fname = args->buf + ARG_MAX; 993 994 /* 995 * Copy the file name. 996 */ 997 error = (segflg == UIO_SYSSPACE) ? 998 copystr(fname, args->fname, PATH_MAX, &length) : 999 copyinstr(fname, args->fname, PATH_MAX, &length); 1000 if (error != 0) 1001 goto err_exit; 1002 1003 /* 1004 * extract arguments first 1005 */ 1006 while ((argp = (caddr_t) (intptr_t) fuword(argv++))) { 1007 if (argp == (caddr_t) -1) { 1008 error = EFAULT; 1009 goto err_exit; 1010 } 1011 if ((error = copyinstr(argp, args->endp, 1012 args->stringspace, &length))) { 1013 if (error == ENAMETOOLONG) 1014 error = E2BIG; 1015 goto err_exit; 1016 } 1017 args->stringspace -= length; 1018 args->endp += length; 1019 args->argc++; 1020 } 1021 1022 args->begin_envv = args->endp; 1023 1024 /* 1025 * extract environment strings 1026 */ 1027 if (envv) { 1028 while ((envp = (caddr_t)(intptr_t)fuword(envv++))) { 1029 if (envp == (caddr_t)-1) { 1030 error = EFAULT; 1031 goto err_exit; 1032 } 1033 if ((error = copyinstr(envp, args->endp, 1034 args->stringspace, &length))) { 1035 if (error == ENAMETOOLONG) 1036 error = E2BIG; 1037 goto err_exit; 1038 } 1039 args->stringspace -= length; 1040 args->endp += length; 1041 args->envc++; 1042 } 1043 } 1044 1045 return (0); 1046 1047 err_exit: 1048 exec_free_args(args); 1049 return (error); 1050 } 1051 1052 static void 1053 exec_free_args(struct image_args *args) 1054 { 1055 1056 if (args->buf) { 1057 kmem_free_wakeup(exec_map, (vm_offset_t)args->buf, 1058 PATH_MAX + ARG_MAX + MAXSHELLCMDLEN); 1059 args->buf = NULL; 1060 } 1061 } 1062 1063 /* 1064 * Copy strings out to the new process address space, constructing 1065 * new arg and env vector tables. Return a pointer to the base 1066 * so that it can be used as the initial stack pointer. 1067 */ 1068 register_t * 1069 exec_copyout_strings(imgp) 1070 struct image_params *imgp; 1071 { 1072 int argc, envc; 1073 char **vectp; 1074 char *stringp, *destp; 1075 register_t *stack_base; 1076 struct ps_strings *arginfo; 1077 struct proc *p; 1078 int szsigcode; 1079 1080 /* 1081 * Calculate string base and vector table pointers. 1082 * Also deal with signal trampoline code for this exec type. 1083 */ 1084 p = imgp->proc; 1085 szsigcode = 0; 1086 arginfo = (struct ps_strings *)p->p_sysent->sv_psstrings; 1087 if (p->p_sysent->sv_szsigcode != NULL) 1088 szsigcode = *(p->p_sysent->sv_szsigcode); 1089 destp = (caddr_t)arginfo - szsigcode - SPARE_USRSPACE - 1090 roundup((ARG_MAX - imgp->args->stringspace), sizeof(char *)); 1091 1092 /* 1093 * install sigcode 1094 */ 1095 if (szsigcode) 1096 copyout(p->p_sysent->sv_sigcode, ((caddr_t)arginfo - 1097 szsigcode), szsigcode); 1098 1099 /* 1100 * If we have a valid auxargs ptr, prepare some room 1101 * on the stack. 1102 */ 1103 if (imgp->auxargs) { 1104 /* 1105 * 'AT_COUNT*2' is size for the ELF Auxargs data. This is for 1106 * lower compatibility. 1107 */ 1108 imgp->auxarg_size = (imgp->auxarg_size) ? imgp->auxarg_size : 1109 (AT_COUNT * 2); 1110 /* 1111 * The '+ 2' is for the null pointers at the end of each of 1112 * the arg and env vector sets,and imgp->auxarg_size is room 1113 * for argument of Runtime loader. 1114 */ 1115 vectp = (char **)(destp - (imgp->args->argc + 1116 imgp->args->envc + 2 + imgp->auxarg_size) * 1117 sizeof(char *)); 1118 1119 } else { 1120 /* 1121 * The '+ 2' is for the null pointers at the end of each of 1122 * the arg and env vector sets 1123 */ 1124 vectp = (char **)(destp - (imgp->args->argc + imgp->args->envc + 2) * 1125 sizeof(char *)); 1126 } 1127 1128 /* 1129 * vectp also becomes our initial stack base 1130 */ 1131 stack_base = (register_t *)vectp; 1132 1133 stringp = imgp->args->begin_argv; 1134 argc = imgp->args->argc; 1135 envc = imgp->args->envc; 1136 1137 /* 1138 * Copy out strings - arguments and environment. 1139 */ 1140 copyout(stringp, destp, ARG_MAX - imgp->args->stringspace); 1141 1142 /* 1143 * Fill in "ps_strings" struct for ps, w, etc. 1144 */ 1145 suword(&arginfo->ps_argvstr, (long)(intptr_t)vectp); 1146 suword(&arginfo->ps_nargvstr, argc); 1147 1148 /* 1149 * Fill in argument portion of vector table. 1150 */ 1151 for (; argc > 0; --argc) { 1152 suword(vectp++, (long)(intptr_t)destp); 1153 while (*stringp++ != 0) 1154 destp++; 1155 destp++; 1156 } 1157 1158 /* a null vector table pointer separates the argp's from the envp's */ 1159 suword(vectp++, 0); 1160 1161 suword(&arginfo->ps_envstr, (long)(intptr_t)vectp); 1162 suword(&arginfo->ps_nenvstr, envc); 1163 1164 /* 1165 * Fill in environment portion of vector table. 1166 */ 1167 for (; envc > 0; --envc) { 1168 suword(vectp++, (long)(intptr_t)destp); 1169 while (*stringp++ != 0) 1170 destp++; 1171 destp++; 1172 } 1173 1174 /* end of vector table is a null pointer */ 1175 suword(vectp, 0); 1176 1177 return (stack_base); 1178 } 1179 1180 /* 1181 * Check permissions of file to execute. 1182 * Called with imgp->vp locked. 1183 * Return 0 for success or error code on failure. 1184 */ 1185 int 1186 exec_check_permissions(imgp) 1187 struct image_params *imgp; 1188 { 1189 struct vnode *vp = imgp->vp; 1190 struct vattr *attr = imgp->attr; 1191 struct thread *td; 1192 int error; 1193 1194 td = curthread; /* XXXKSE */ 1195 1196 /* Get file attributes */ 1197 error = VOP_GETATTR(vp, attr, td->td_ucred, td); 1198 if (error) 1199 return (error); 1200 1201 #ifdef MAC 1202 error = mac_check_vnode_exec(td->td_ucred, imgp->vp, imgp); 1203 if (error) 1204 return (error); 1205 #endif 1206 1207 /* 1208 * 1) Check if file execution is disabled for the filesystem that this 1209 * file resides on. 1210 * 2) Insure that at least one execute bit is on - otherwise root 1211 * will always succeed, and we don't want to happen unless the 1212 * file really is executable. 1213 * 3) Insure that the file is a regular file. 1214 */ 1215 if ((vp->v_mount->mnt_flag & MNT_NOEXEC) || 1216 ((attr->va_mode & 0111) == 0) || 1217 (attr->va_type != VREG)) 1218 return (EACCES); 1219 1220 /* 1221 * Zero length files can't be exec'd 1222 */ 1223 if (attr->va_size == 0) 1224 return (ENOEXEC); 1225 1226 /* 1227 * Check for execute permission to file based on current credentials. 1228 */ 1229 error = VOP_ACCESS(vp, VEXEC, td->td_ucred, td); 1230 if (error) 1231 return (error); 1232 1233 /* 1234 * Check number of open-for-writes on the file and deny execution 1235 * if there are any. 1236 */ 1237 if (vp->v_writecount) 1238 return (ETXTBSY); 1239 1240 /* 1241 * Call filesystem specific open routine (which does nothing in the 1242 * general case). 1243 */ 1244 error = VOP_OPEN(vp, FREAD, td->td_ucred, td, -1); 1245 return (error); 1246 } 1247 1248 /* 1249 * Exec handler registration 1250 */ 1251 int 1252 exec_register(execsw_arg) 1253 const struct execsw *execsw_arg; 1254 { 1255 const struct execsw **es, **xs, **newexecsw; 1256 int count = 2; /* New slot and trailing NULL */ 1257 1258 if (execsw) 1259 for (es = execsw; *es; es++) 1260 count++; 1261 newexecsw = malloc(count * sizeof(*es), M_TEMP, M_WAITOK); 1262 if (newexecsw == NULL) 1263 return (ENOMEM); 1264 xs = newexecsw; 1265 if (execsw) 1266 for (es = execsw; *es; es++) 1267 *xs++ = *es; 1268 *xs++ = execsw_arg; 1269 *xs = NULL; 1270 if (execsw) 1271 free(execsw, M_TEMP); 1272 execsw = newexecsw; 1273 return (0); 1274 } 1275 1276 int 1277 exec_unregister(execsw_arg) 1278 const struct execsw *execsw_arg; 1279 { 1280 const struct execsw **es, **xs, **newexecsw; 1281 int count = 1; 1282 1283 if (execsw == NULL) 1284 panic("unregister with no handlers left?\n"); 1285 1286 for (es = execsw; *es; es++) { 1287 if (*es == execsw_arg) 1288 break; 1289 } 1290 if (*es == NULL) 1291 return (ENOENT); 1292 for (es = execsw; *es; es++) 1293 if (*es != execsw_arg) 1294 count++; 1295 newexecsw = malloc(count * sizeof(*es), M_TEMP, M_WAITOK); 1296 if (newexecsw == NULL) 1297 return (ENOMEM); 1298 xs = newexecsw; 1299 for (es = execsw; *es; es++) 1300 if (*es != execsw_arg) 1301 *xs++ = *es; 1302 *xs = NULL; 1303 if (execsw) 1304 free(execsw, M_TEMP); 1305 execsw = newexecsw; 1306 return (0); 1307 } 1308