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/timers.h> 62 #include <sys/vnode.h> 63 #ifdef KTRACE 64 #include <sys/ktrace.h> 65 #endif 66 67 #include <vm/vm.h> 68 #include <vm/vm_param.h> 69 #include <vm/pmap.h> 70 #include <vm/vm_page.h> 71 #include <vm/vm_map.h> 72 #include <vm/vm_kern.h> 73 #include <vm/vm_extern.h> 74 #include <vm/vm_object.h> 75 #include <vm/vm_pager.h> 76 77 #ifdef HWPMC_HOOKS 78 #include <sys/pmckern.h> 79 #endif 80 81 #include <machine/reg.h> 82 83 MALLOC_DEFINE(M_PARGS, "proc-args", "Process arguments"); 84 85 static int sysctl_kern_ps_strings(SYSCTL_HANDLER_ARGS); 86 static int sysctl_kern_usrstack(SYSCTL_HANDLER_ARGS); 87 static int sysctl_kern_stackprot(SYSCTL_HANDLER_ARGS); 88 static int do_execve(struct thread *td, struct image_args *args, 89 struct mac *mac_p); 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); 185 186 if (error == 0) 187 error = kern_execve(td, &args, NULL); 188 189 exec_free_args(&args); 190 191 return (error); 192 } 193 194 #ifndef _SYS_SYSPROTO_H_ 195 struct __mac_execve_args { 196 char *fname; 197 char **argv; 198 char **envv; 199 struct mac *mac_p; 200 }; 201 #endif 202 203 /* 204 * MPSAFE 205 */ 206 int 207 __mac_execve(td, uap) 208 struct thread *td; 209 struct __mac_execve_args /* { 210 char *fname; 211 char **argv; 212 char **envv; 213 struct mac *mac_p; 214 } */ *uap; 215 { 216 #ifdef MAC 217 int error; 218 struct image_args args; 219 220 error = exec_copyin_args(&args, uap->fname, UIO_USERSPACE, 221 uap->argv, uap->envv); 222 223 if (error == 0) 224 error = kern_execve(td, &args, uap->mac_p); 225 226 exec_free_args(&args); 227 228 return (error); 229 #else 230 return (ENOSYS); 231 #endif 232 } 233 234 /* 235 * XXX: kern_execve has the astonishing property of not always 236 * returning to the caller. If sufficiently bad things happen during 237 * the call to do_execve(), it can end up calling exit1(); as a result, 238 * callers must avoid doing anything which they might need to undo 239 * (e.g., allocating memory). 240 */ 241 int 242 kern_execve(td, args, mac_p) 243 struct thread *td; 244 struct image_args *args; 245 struct mac *mac_p; 246 { 247 struct proc *p = td->td_proc; 248 int error; 249 250 if (p->p_flag & P_HADTHREADS) { 251 PROC_LOCK(p); 252 if (thread_single(SINGLE_BOUNDARY)) { 253 PROC_UNLOCK(p); 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 ndp = &nd; 363 NDINIT(ndp, LOOKUP, ISOPEN | LOCKLEAF | FOLLOW | SAVENAME | MPSAFE, 364 UIO_SYSSPACE, args->fname, td); 365 366 interpret: 367 error = namei(ndp); 368 if (error) 369 goto exec_fail; 370 371 vfslocked = NDHASGIANT(ndp); 372 imgp->vp = ndp->ni_vp; 373 374 /* 375 * Check file permissions (also 'opens' file) 376 */ 377 error = exec_check_permissions(imgp); 378 if (error) 379 goto exec_fail_dealloc; 380 381 imgp->object = imgp->vp->v_object; 382 if (imgp->object != NULL) 383 vm_object_reference(imgp->object); 384 385 /* 386 * Set VV_TEXT now so no one can write to the executable while we're 387 * activating it. 388 * 389 * Remember if this was set before and unset it in case this is not 390 * actually an executable image. 391 */ 392 textset = imgp->vp->v_vflag & VV_TEXT; 393 imgp->vp->v_vflag |= VV_TEXT; 394 395 error = exec_map_first_page(imgp); 396 if (error) 397 goto exec_fail_dealloc; 398 399 /* 400 * If the current process has a special image activator it 401 * wants to try first, call it. For example, emulating shell 402 * scripts differently. 403 */ 404 error = -1; 405 if ((img_first = imgp->proc->p_sysent->sv_imgact_try) != NULL) 406 error = img_first(imgp); 407 408 /* 409 * Loop through the list of image activators, calling each one. 410 * An activator returns -1 if there is no match, 0 on success, 411 * and an error otherwise. 412 */ 413 for (i = 0; error == -1 && execsw[i]; ++i) { 414 if (execsw[i]->ex_imgact == NULL || 415 execsw[i]->ex_imgact == img_first) { 416 continue; 417 } 418 error = (*execsw[i]->ex_imgact)(imgp); 419 } 420 421 if (error) { 422 if (error == -1) { 423 if (textset == 0) 424 imgp->vp->v_vflag &= ~VV_TEXT; 425 error = ENOEXEC; 426 } 427 goto exec_fail_dealloc; 428 } 429 430 /* 431 * Special interpreter operation, cleanup and loop up to try to 432 * activate the interpreter. 433 */ 434 if (imgp->interpreted) { 435 exec_unmap_first_page(imgp); 436 /* 437 * VV_TEXT needs to be unset for scripts. There is a short 438 * period before we determine that something is a script where 439 * VV_TEXT will be set. The vnode lock is held over this 440 * entire period so nothing should illegitimately be blocked. 441 */ 442 imgp->vp->v_vflag &= ~VV_TEXT; 443 /* free name buffer and old vnode */ 444 NDFREE(ndp, NDF_ONLY_PNBUF); 445 #ifdef MAC 446 interplabel = mac_vnode_label_alloc(); 447 mac_copy_vnode_label(ndp->ni_vp->v_label, interplabel); 448 #endif 449 vput(ndp->ni_vp); 450 vm_object_deallocate(imgp->object); 451 imgp->object = NULL; 452 VFS_UNLOCK_GIANT(vfslocked); 453 vfslocked = 0; 454 /* set new name to that of the interpreter */ 455 NDINIT(ndp, LOOKUP, LOCKLEAF | FOLLOW | SAVENAME | MPSAFE, 456 UIO_SYSSPACE, imgp->interpreter_name, td); 457 goto interpret; 458 } 459 460 /* 461 * Copy out strings (args and env) and initialize stack base 462 */ 463 if (p->p_sysent->sv_copyout_strings) 464 stack_base = (*p->p_sysent->sv_copyout_strings)(imgp); 465 else 466 stack_base = exec_copyout_strings(imgp); 467 468 /* 469 * If custom stack fixup routine present for this process 470 * let it do the stack setup. 471 * Else stuff argument count as first item on stack 472 */ 473 if (p->p_sysent->sv_fixup != NULL) 474 (*p->p_sysent->sv_fixup)(&stack_base, imgp); 475 else 476 suword(--stack_base, imgp->args->argc); 477 478 /* 479 * For security and other reasons, the file descriptor table cannot 480 * be shared after an exec. 481 */ 482 fdunshare(p, td); 483 484 /* Clear POSIX timers */ 485 itimers_event_hook(p, ITIMER_EV_EXEC); 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 fdcloseexec(td); 501 502 /* Get a reference to the vnode prior to locking the proc */ 503 VREF(ndp->ni_vp); 504 505 /* 506 * For security and other reasons, signal handlers cannot 507 * be shared after an exec. The new process gets a copy of the old 508 * handlers. In execsigs(), the new process will have its signals 509 * reset. 510 */ 511 PROC_LOCK(p); 512 if (sigacts_shared(p->p_sigacts)) { 513 oldsigacts = p->p_sigacts; 514 PROC_UNLOCK(p); 515 newsigacts = sigacts_alloc(); 516 sigacts_copy(newsigacts, oldsigacts); 517 PROC_LOCK(p); 518 p->p_sigacts = newsigacts; 519 } else 520 oldsigacts = NULL; 521 522 /* Stop profiling */ 523 stopprofclock(p); 524 525 /* reset caught signals */ 526 execsigs(p); 527 528 /* name this process - nameiexec(p, ndp) */ 529 len = min(ndp->ni_cnd.cn_namelen,MAXCOMLEN); 530 bcopy(ndp->ni_cnd.cn_nameptr, p->p_comm, len); 531 p->p_comm[len] = 0; 532 533 /* 534 * mark as execed, wakeup the process that vforked (if any) and tell 535 * it that it now has its own resources back 536 */ 537 p->p_flag |= P_EXEC; 538 if (p->p_pptr && (p->p_flag & P_PPWAIT)) { 539 p->p_flag &= ~P_PPWAIT; 540 wakeup(p->p_pptr); 541 } 542 543 /* 544 * Implement image setuid/setgid. 545 * 546 * Don't honor setuid/setgid if the filesystem prohibits it or if 547 * the process is being traced. 548 * 549 * XXXMAC: For the time being, use NOSUID to also prohibit 550 * transitions on the file system. 551 */ 552 oldcred = p->p_ucred; 553 credential_changing = 0; 554 credential_changing |= (attr.va_mode & VSUID) && oldcred->cr_uid != 555 attr.va_uid; 556 credential_changing |= (attr.va_mode & VSGID) && oldcred->cr_gid != 557 attr.va_gid; 558 #ifdef MAC 559 will_transition = mac_execve_will_transition(oldcred, imgp->vp, 560 interplabel, imgp); 561 credential_changing |= will_transition; 562 #endif 563 564 if (credential_changing && 565 (imgp->vp->v_mount->mnt_flag & MNT_NOSUID) == 0 && 566 (p->p_flag & P_TRACED) == 0) { 567 /* 568 * Turn off syscall tracing for set-id programs, except for 569 * root. Record any set-id flags first to make sure that 570 * we do not regain any tracing during a possible block. 571 */ 572 setsugid(p); 573 #ifdef KTRACE 574 if (p->p_tracevp != NULL && suser_cred(oldcred, SUSER_ALLOWJAIL)) { 575 mtx_lock(&ktrace_mtx); 576 p->p_traceflag = 0; 577 tracevp = p->p_tracevp; 578 p->p_tracevp = NULL; 579 tracecred = p->p_tracecred; 580 p->p_tracecred = NULL; 581 mtx_unlock(&ktrace_mtx); 582 } 583 #endif 584 /* 585 * Close any file descriptors 0..2 that reference procfs, 586 * then make sure file descriptors 0..2 are in use. 587 * 588 * setugidsafety() may call closef() and then pfind() 589 * which may grab the process lock. 590 * fdcheckstd() may call falloc() which may block to 591 * allocate memory, so temporarily drop the process lock. 592 */ 593 PROC_UNLOCK(p); 594 setugidsafety(td); 595 error = fdcheckstd(td); 596 if (error != 0) 597 goto done1; 598 PROC_LOCK(p); 599 /* 600 * Set the new credentials. 601 */ 602 crcopy(newcred, oldcred); 603 if (attr.va_mode & VSUID) 604 change_euid(newcred, euip); 605 if (attr.va_mode & VSGID) 606 change_egid(newcred, attr.va_gid); 607 #ifdef MAC 608 if (will_transition) { 609 mac_execve_transition(oldcred, newcred, imgp->vp, 610 interplabel, imgp); 611 } 612 #endif 613 /* 614 * Implement correct POSIX saved-id behavior. 615 * 616 * XXXMAC: Note that the current logic will save the 617 * uid and gid if a MAC domain transition occurs, even 618 * though maybe it shouldn't. 619 */ 620 change_svuid(newcred, newcred->cr_uid); 621 change_svgid(newcred, newcred->cr_gid); 622 p->p_ucred = newcred; 623 newcred = NULL; 624 } else { 625 if (oldcred->cr_uid == oldcred->cr_ruid && 626 oldcred->cr_gid == oldcred->cr_rgid) 627 p->p_flag &= ~P_SUGID; 628 /* 629 * Implement correct POSIX saved-id behavior. 630 * 631 * XXX: It's not clear that the existing behavior is 632 * POSIX-compliant. A number of sources indicate that the 633 * saved uid/gid should only be updated if the new ruid is 634 * not equal to the old ruid, or the new euid is not equal 635 * to the old euid and the new euid is not equal to the old 636 * ruid. The FreeBSD code always updates the saved uid/gid. 637 * Also, this code uses the new (replaced) euid and egid as 638 * the source, which may or may not be the right ones to use. 639 */ 640 if (oldcred->cr_svuid != oldcred->cr_uid || 641 oldcred->cr_svgid != oldcred->cr_gid) { 642 crcopy(newcred, oldcred); 643 change_svuid(newcred, newcred->cr_uid); 644 change_svgid(newcred, newcred->cr_gid); 645 p->p_ucred = newcred; 646 newcred = NULL; 647 } 648 } 649 650 /* 651 * Store the vp for use in procfs. This vnode was referenced prior 652 * to locking the proc lock. 653 */ 654 textvp = p->p_textvp; 655 p->p_textvp = ndp->ni_vp; 656 657 /* 658 * Notify others that we exec'd, and clear the P_INEXEC flag 659 * as we're now a bona fide freshly-execed process. 660 */ 661 KNOTE_LOCKED(&p->p_klist, NOTE_EXEC); 662 p->p_flag &= ~P_INEXEC; 663 664 /* 665 * If tracing the process, trap to debugger so breakpoints 666 * can be set before the program executes. 667 * Use tdsignal to deliver signal to current thread, use 668 * psignal may cause the signal to be delivered to wrong thread 669 * because that thread will exit, remember we are going to enter 670 * single thread mode. 671 */ 672 if (p->p_flag & P_TRACED) 673 tdsignal(td, SIGTRAP, NULL, SIGTARGET_TD); 674 675 /* clear "fork but no exec" flag, as we _are_ execing */ 676 p->p_acflag &= ~AFORK; 677 678 /* 679 * Free any previous argument cache and replace it with 680 * the new argument cache, if any. 681 */ 682 oldargs = p->p_args; 683 p->p_args = newargs; 684 newargs = NULL; 685 686 #ifdef HWPMC_HOOKS 687 /* 688 * Check if system-wide sampling is in effect or if the 689 * current process is using PMCs. If so, do exec() time 690 * processing. This processing needs to happen AFTER the 691 * P_INEXEC flag is cleared. 692 * 693 * The proc lock needs to be released before taking the PMC 694 * SX. 695 */ 696 if (PMC_SYSTEM_SAMPLING_ACTIVE() || PMC_PROC_IS_USING_PMCS(p)) { 697 PROC_UNLOCK(p); 698 pe.pm_credentialschanged = credential_changing; 699 pe.pm_entryaddr = imgp->entry_addr; 700 701 PMC_CALL_HOOK_X(td, PMC_FN_PROCESS_EXEC, (void *) &pe); 702 } else 703 PROC_UNLOCK(p); 704 #else /* !HWPMC_HOOKS */ 705 PROC_UNLOCK(p); 706 #endif 707 708 /* Set values passed into the program in registers. */ 709 if (p->p_sysent->sv_setregs) 710 (*p->p_sysent->sv_setregs)(td, imgp->entry_addr, 711 (u_long)(uintptr_t)stack_base, imgp->ps_strings); 712 else 713 exec_setregs(td, imgp->entry_addr, 714 (u_long)(uintptr_t)stack_base, imgp->ps_strings); 715 716 vfs_mark_atime(imgp->vp, td); 717 718 done1: 719 /* 720 * Free any resources malloc'd earlier that we didn't use. 721 */ 722 uifree(euip); 723 if (newcred == NULL) 724 crfree(oldcred); 725 else 726 crfree(newcred); 727 /* 728 * Handle deferred decrement of ref counts. 729 */ 730 if (textvp != NULL) 731 vrele(textvp); 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 if (oldargs != NULL) 741 pargs_drop(oldargs); 742 if (newargs != NULL) 743 pargs_drop(newargs); 744 if (oldsigacts != NULL) 745 sigacts_free(oldsigacts); 746 747 exec_fail_dealloc: 748 749 /* 750 * free various allocated resources 751 */ 752 if (imgp->firstpage != NULL) 753 exec_unmap_first_page(imgp); 754 755 if (imgp->vp != NULL) { 756 NDFREE(ndp, NDF_ONLY_PNBUF); 757 vput(imgp->vp); 758 } 759 760 if (imgp->object != NULL) 761 vm_object_deallocate(imgp->object); 762 763 if (error == 0) { 764 /* 765 * Stop the process here if its stop event mask has 766 * the S_EXEC bit set. 767 */ 768 STOPEVENT(p, S_EXEC, 0); 769 goto done2; 770 } 771 772 exec_fail: 773 /* we're done here, clear P_INEXEC */ 774 PROC_LOCK(p); 775 p->p_flag &= ~P_INEXEC; 776 PROC_UNLOCK(p); 777 778 if (imgp->vmspace_destroyed) { 779 /* sorry, no more process anymore. exit gracefully */ 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 exit1(td, W_EXITCODE(0, SIGABRT)); 788 /* NOT REACHED */ 789 error = 0; 790 } 791 done2: 792 #ifdef MAC 793 mac_execve_exit(imgp); 794 if (interplabel != NULL) 795 mac_vnode_label_free(interplabel); 796 #endif 797 VFS_UNLOCK_GIANT(vfslocked); 798 return (error); 799 } 800 801 int 802 exec_map_first_page(imgp) 803 struct image_params *imgp; 804 { 805 int rv, i; 806 int initial_pagein; 807 vm_page_t ma[VM_INITIAL_PAGEIN]; 808 vm_object_t object; 809 810 if (imgp->firstpage != NULL) 811 exec_unmap_first_page(imgp); 812 813 object = imgp->vp->v_object; 814 if (object == NULL) 815 return (EACCES); 816 VM_OBJECT_LOCK(object); 817 ma[0] = vm_page_grab(object, 0, VM_ALLOC_NORMAL | VM_ALLOC_RETRY); 818 if ((ma[0]->valid & VM_PAGE_BITS_ALL) != VM_PAGE_BITS_ALL) { 819 initial_pagein = VM_INITIAL_PAGEIN; 820 if (initial_pagein > object->size) 821 initial_pagein = object->size; 822 for (i = 1; i < initial_pagein; i++) { 823 if ((ma[i] = vm_page_lookup(object, i)) != NULL) { 824 if (ma[i]->valid) 825 break; 826 vm_page_lock_queues(); 827 if ((ma[i]->flags & PG_BUSY) || ma[i]->busy) { 828 vm_page_unlock_queues(); 829 break; 830 } 831 vm_page_busy(ma[i]); 832 vm_page_unlock_queues(); 833 } else { 834 ma[i] = vm_page_alloc(object, i, 835 VM_ALLOC_NORMAL); 836 if (ma[i] == NULL) 837 break; 838 } 839 } 840 initial_pagein = i; 841 rv = vm_pager_get_pages(object, ma, initial_pagein, 0); 842 ma[0] = vm_page_lookup(object, 0); 843 if ((rv != VM_PAGER_OK) || (ma[0] == NULL) || 844 (ma[0]->valid == 0)) { 845 if (ma[0]) { 846 vm_page_lock_queues(); 847 pmap_remove_all(ma[0]); 848 vm_page_free(ma[0]); 849 vm_page_unlock_queues(); 850 } 851 VM_OBJECT_UNLOCK(object); 852 return (EIO); 853 } 854 } 855 vm_page_lock_queues(); 856 vm_page_hold(ma[0]); 857 vm_page_wakeup(ma[0]); 858 vm_page_unlock_queues(); 859 VM_OBJECT_UNLOCK(object); 860 861 imgp->firstpage = sf_buf_alloc(ma[0], 0); 862 imgp->image_header = (char *)sf_buf_kva(imgp->firstpage); 863 864 return (0); 865 } 866 867 void 868 exec_unmap_first_page(imgp) 869 struct image_params *imgp; 870 { 871 vm_page_t m; 872 873 if (imgp->firstpage != NULL) { 874 m = sf_buf_page(imgp->firstpage); 875 sf_buf_free(imgp->firstpage); 876 imgp->firstpage = NULL; 877 vm_page_lock_queues(); 878 vm_page_unhold(m); 879 vm_page_unlock_queues(); 880 } 881 } 882 883 /* 884 * Destroy old address space, and allocate a new stack 885 * The new stack is only SGROWSIZ large because it is grown 886 * automatically in trap.c. 887 */ 888 int 889 exec_new_vmspace(imgp, sv) 890 struct image_params *imgp; 891 struct sysentvec *sv; 892 { 893 int error; 894 struct proc *p = imgp->proc; 895 struct vmspace *vmspace = p->p_vmspace; 896 vm_offset_t stack_addr; 897 vm_map_t map; 898 899 imgp->vmspace_destroyed = 1; 900 901 /* Called with Giant held, do not depend on it! */ 902 EVENTHANDLER_INVOKE(process_exec, p); 903 904 /* 905 * Here is as good a place as any to do any resource limit cleanups. 906 * This is needed if a 64 bit binary exec's a 32 bit binary - the 907 * data size limit may need to be changed to a value that makes 908 * sense for the 32 bit binary. 909 */ 910 if (sv->sv_fixlimits != NULL) 911 sv->sv_fixlimits(imgp); 912 913 /* 914 * Blow away entire process VM, if address space not shared, 915 * otherwise, create a new VM space so that other threads are 916 * not disrupted 917 */ 918 map = &vmspace->vm_map; 919 if (vmspace->vm_refcnt == 1 && vm_map_min(map) == sv->sv_minuser && 920 vm_map_max(map) == sv->sv_maxuser) { 921 shmexit(vmspace); 922 pmap_remove_pages(vmspace_pmap(vmspace), vm_map_min(map), 923 vm_map_max(map)); 924 vm_map_remove(map, vm_map_min(map), vm_map_max(map)); 925 } else { 926 vmspace_exec(p, sv->sv_minuser, sv->sv_maxuser); 927 vmspace = p->p_vmspace; 928 map = &vmspace->vm_map; 929 } 930 931 /* Allocate a new stack */ 932 stack_addr = sv->sv_usrstack - maxssiz; 933 error = vm_map_stack(map, stack_addr, (vm_size_t)maxssiz, 934 sv->sv_stackprot, VM_PROT_ALL, MAP_STACK_GROWS_DOWN); 935 if (error) 936 return (error); 937 938 #ifdef __ia64__ 939 /* Allocate a new register stack */ 940 stack_addr = IA64_BACKINGSTORE; 941 error = vm_map_stack(map, stack_addr, (vm_size_t)maxssiz, 942 sv->sv_stackprot, VM_PROT_ALL, MAP_STACK_GROWS_UP); 943 if (error) 944 return (error); 945 #endif 946 947 /* vm_ssize and vm_maxsaddr are somewhat antiquated concepts in the 948 * VM_STACK case, but they are still used to monitor the size of the 949 * process stack so we can check the stack rlimit. 950 */ 951 vmspace->vm_ssize = sgrowsiz >> PAGE_SHIFT; 952 vmspace->vm_maxsaddr = (char *)sv->sv_usrstack - maxssiz; 953 954 return (0); 955 } 956 957 /* 958 * Copy out argument and environment strings from the old process 959 * address space into the temporary string buffer. 960 */ 961 int 962 exec_copyin_args(struct image_args *args, char *fname, 963 enum uio_seg segflg, char **argv, char **envv) 964 { 965 char *argp, *envp; 966 int error; 967 size_t length; 968 969 error = 0; 970 971 bzero(args, sizeof(*args)); 972 if (argv == NULL) 973 return (EFAULT); 974 /* 975 * Allocate temporary demand zeroed space for argument and 976 * environment strings: 977 * 978 * o ARG_MAX for argument and environment; 979 * o MAXSHELLCMDLEN for the name of interpreters. 980 */ 981 args->buf = (char *) kmem_alloc_wait(exec_map, 982 PATH_MAX + ARG_MAX + MAXSHELLCMDLEN); 983 if (args->buf == NULL) 984 return (ENOMEM); 985 args->begin_argv = args->buf; 986 args->endp = args->begin_argv; 987 args->stringspace = ARG_MAX; 988 989 args->fname = args->buf + ARG_MAX; 990 991 /* 992 * Copy the file name. 993 */ 994 error = (segflg == UIO_SYSSPACE) ? 995 copystr(fname, args->fname, PATH_MAX, &length) : 996 copyinstr(fname, args->fname, PATH_MAX, &length); 997 if (error != 0) 998 return (error); 999 1000 /* 1001 * extract arguments first 1002 */ 1003 while ((argp = (caddr_t) (intptr_t) fuword(argv++))) { 1004 if (argp == (caddr_t) -1) 1005 return (EFAULT); 1006 if ((error = copyinstr(argp, args->endp, 1007 args->stringspace, &length))) { 1008 if (error == ENAMETOOLONG) 1009 return (E2BIG); 1010 return (error); 1011 } 1012 args->stringspace -= length; 1013 args->endp += length; 1014 args->argc++; 1015 } 1016 1017 args->begin_envv = args->endp; 1018 1019 /* 1020 * extract environment strings 1021 */ 1022 if (envv) { 1023 while ((envp = (caddr_t)(intptr_t)fuword(envv++))) { 1024 if (envp == (caddr_t)-1) 1025 return (EFAULT); 1026 if ((error = copyinstr(envp, args->endp, 1027 args->stringspace, &length))) { 1028 if (error == ENAMETOOLONG) 1029 return (E2BIG); 1030 return (error); 1031 } 1032 args->stringspace -= length; 1033 args->endp += length; 1034 args->envc++; 1035 } 1036 } 1037 1038 return (0); 1039 } 1040 1041 void 1042 exec_free_args(struct image_args *args) 1043 { 1044 1045 if (args->buf) { 1046 kmem_free_wakeup(exec_map, (vm_offset_t)args->buf, 1047 PATH_MAX + ARG_MAX + MAXSHELLCMDLEN); 1048 args->buf = NULL; 1049 } 1050 } 1051 1052 /* 1053 * Copy strings out to the new process address space, constructing 1054 * new arg and env vector tables. Return a pointer to the base 1055 * so that it can be used as the initial stack pointer. 1056 */ 1057 register_t * 1058 exec_copyout_strings(imgp) 1059 struct image_params *imgp; 1060 { 1061 int argc, envc; 1062 char **vectp; 1063 char *stringp, *destp; 1064 register_t *stack_base; 1065 struct ps_strings *arginfo; 1066 struct proc *p; 1067 int szsigcode; 1068 1069 /* 1070 * Calculate string base and vector table pointers. 1071 * Also deal with signal trampoline code for this exec type. 1072 */ 1073 p = imgp->proc; 1074 szsigcode = 0; 1075 arginfo = (struct ps_strings *)p->p_sysent->sv_psstrings; 1076 if (p->p_sysent->sv_szsigcode != NULL) 1077 szsigcode = *(p->p_sysent->sv_szsigcode); 1078 destp = (caddr_t)arginfo - szsigcode - SPARE_USRSPACE - 1079 roundup((ARG_MAX - imgp->args->stringspace), sizeof(char *)); 1080 1081 /* 1082 * install sigcode 1083 */ 1084 if (szsigcode) 1085 copyout(p->p_sysent->sv_sigcode, ((caddr_t)arginfo - 1086 szsigcode), szsigcode); 1087 1088 /* 1089 * If we have a valid auxargs ptr, prepare some room 1090 * on the stack. 1091 */ 1092 if (imgp->auxargs) { 1093 /* 1094 * 'AT_COUNT*2' is size for the ELF Auxargs data. This is for 1095 * lower compatibility. 1096 */ 1097 imgp->auxarg_size = (imgp->auxarg_size) ? imgp->auxarg_size : 1098 (AT_COUNT * 2); 1099 /* 1100 * The '+ 2' is for the null pointers at the end of each of 1101 * the arg and env vector sets,and imgp->auxarg_size is room 1102 * for argument of Runtime loader. 1103 */ 1104 vectp = (char **)(destp - (imgp->args->argc + 1105 imgp->args->envc + 2 + imgp->auxarg_size) * 1106 sizeof(char *)); 1107 1108 } else { 1109 /* 1110 * The '+ 2' is for the null pointers at the end of each of 1111 * the arg and env vector sets 1112 */ 1113 vectp = (char **)(destp - (imgp->args->argc + imgp->args->envc + 2) * 1114 sizeof(char *)); 1115 } 1116 1117 /* 1118 * vectp also becomes our initial stack base 1119 */ 1120 stack_base = (register_t *)vectp; 1121 1122 stringp = imgp->args->begin_argv; 1123 argc = imgp->args->argc; 1124 envc = imgp->args->envc; 1125 1126 /* 1127 * Copy out strings - arguments and environment. 1128 */ 1129 copyout(stringp, destp, ARG_MAX - imgp->args->stringspace); 1130 1131 /* 1132 * Fill in "ps_strings" struct for ps, w, etc. 1133 */ 1134 suword(&arginfo->ps_argvstr, (long)(intptr_t)vectp); 1135 suword(&arginfo->ps_nargvstr, argc); 1136 1137 /* 1138 * Fill in argument portion of vector table. 1139 */ 1140 for (; argc > 0; --argc) { 1141 suword(vectp++, (long)(intptr_t)destp); 1142 while (*stringp++ != 0) 1143 destp++; 1144 destp++; 1145 } 1146 1147 /* a null vector table pointer separates the argp's from the envp's */ 1148 suword(vectp++, 0); 1149 1150 suword(&arginfo->ps_envstr, (long)(intptr_t)vectp); 1151 suword(&arginfo->ps_nenvstr, envc); 1152 1153 /* 1154 * Fill in environment portion of vector table. 1155 */ 1156 for (; envc > 0; --envc) { 1157 suword(vectp++, (long)(intptr_t)destp); 1158 while (*stringp++ != 0) 1159 destp++; 1160 destp++; 1161 } 1162 1163 /* end of vector table is a null pointer */ 1164 suword(vectp, 0); 1165 1166 return (stack_base); 1167 } 1168 1169 /* 1170 * Check permissions of file to execute. 1171 * Called with imgp->vp locked. 1172 * Return 0 for success or error code on failure. 1173 */ 1174 int 1175 exec_check_permissions(imgp) 1176 struct image_params *imgp; 1177 { 1178 struct vnode *vp = imgp->vp; 1179 struct vattr *attr = imgp->attr; 1180 struct thread *td; 1181 int error; 1182 1183 td = curthread; /* XXXKSE */ 1184 1185 /* Get file attributes */ 1186 error = VOP_GETATTR(vp, attr, td->td_ucred, td); 1187 if (error) 1188 return (error); 1189 1190 #ifdef MAC 1191 error = mac_check_vnode_exec(td->td_ucred, imgp->vp, imgp); 1192 if (error) 1193 return (error); 1194 #endif 1195 1196 /* 1197 * 1) Check if file execution is disabled for the filesystem that this 1198 * file resides on. 1199 * 2) Insure that at least one execute bit is on - otherwise root 1200 * will always succeed, and we don't want to happen unless the 1201 * file really is executable. 1202 * 3) Insure that the file is a regular file. 1203 */ 1204 if ((vp->v_mount->mnt_flag & MNT_NOEXEC) || 1205 ((attr->va_mode & 0111) == 0) || 1206 (attr->va_type != VREG)) 1207 return (EACCES); 1208 1209 /* 1210 * Zero length files can't be exec'd 1211 */ 1212 if (attr->va_size == 0) 1213 return (ENOEXEC); 1214 1215 /* 1216 * Check for execute permission to file based on current credentials. 1217 */ 1218 error = VOP_ACCESS(vp, VEXEC, td->td_ucred, td); 1219 if (error) 1220 return (error); 1221 1222 /* 1223 * Check number of open-for-writes on the file and deny execution 1224 * if there are any. 1225 */ 1226 if (vp->v_writecount) 1227 return (ETXTBSY); 1228 1229 /* 1230 * Call filesystem specific open routine (which does nothing in the 1231 * general case). 1232 */ 1233 error = VOP_OPEN(vp, FREAD, td->td_ucred, td, -1); 1234 return (error); 1235 } 1236 1237 /* 1238 * Exec handler registration 1239 */ 1240 int 1241 exec_register(execsw_arg) 1242 const struct execsw *execsw_arg; 1243 { 1244 const struct execsw **es, **xs, **newexecsw; 1245 int count = 2; /* New slot and trailing NULL */ 1246 1247 if (execsw) 1248 for (es = execsw; *es; es++) 1249 count++; 1250 newexecsw = malloc(count * sizeof(*es), M_TEMP, M_WAITOK); 1251 if (newexecsw == NULL) 1252 return (ENOMEM); 1253 xs = newexecsw; 1254 if (execsw) 1255 for (es = execsw; *es; es++) 1256 *xs++ = *es; 1257 *xs++ = execsw_arg; 1258 *xs = NULL; 1259 if (execsw) 1260 free(execsw, M_TEMP); 1261 execsw = newexecsw; 1262 return (0); 1263 } 1264 1265 int 1266 exec_unregister(execsw_arg) 1267 const struct execsw *execsw_arg; 1268 { 1269 const struct execsw **es, **xs, **newexecsw; 1270 int count = 1; 1271 1272 if (execsw == NULL) 1273 panic("unregister with no handlers left?\n"); 1274 1275 for (es = execsw; *es; es++) { 1276 if (*es == execsw_arg) 1277 break; 1278 } 1279 if (*es == NULL) 1280 return (ENOENT); 1281 for (es = execsw; *es; es++) 1282 if (*es != execsw_arg) 1283 count++; 1284 newexecsw = malloc(count * sizeof(*es), M_TEMP, M_WAITOK); 1285 if (newexecsw == NULL) 1286 return (ENOMEM); 1287 xs = newexecsw; 1288 for (es = execsw; *es; es++) 1289 if (*es != execsw_arg) 1290 *xs++ = *es; 1291 *xs = NULL; 1292 if (execsw) 1293 free(execsw, M_TEMP); 1294 execsw = newexecsw; 1295 return (0); 1296 } 1297