2 * Copyright (c) 1993, David Greenman
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
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.
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
27 #include <sys/cdefs.h>
28 __FBSDID("$FreeBSD$");
30 #include "opt_capsicum.h"
31 #include "opt_hwpmc_hooks.h"
32 #include "opt_kdtrace.h"
33 #include "opt_ktrace.h"
36 #include <sys/param.h>
37 #include <sys/capability.h>
38 #include <sys/systm.h>
39 #include <sys/capability.h>
40 #include <sys/eventhandler.h>
42 #include <sys/mutex.h>
43 #include <sys/sysproto.h>
44 #include <sys/signalvar.h>
45 #include <sys/kernel.h>
46 #include <sys/mount.h>
47 #include <sys/filedesc.h>
48 #include <sys/fcntl.h>
51 #include <sys/imgact.h>
52 #include <sys/imgact_elf.h>
54 #include <sys/malloc.h>
57 #include <sys/pioctl.h>
58 #include <sys/namei.h>
59 #include <sys/resourcevar.h>
60 #include <sys/rwlock.h>
61 #include <sys/sched.h>
63 #include <sys/sf_buf.h>
64 #include <sys/syscallsubr.h>
65 #include <sys/sysent.h>
67 #include <sys/sysctl.h>
68 #include <sys/vnode.h>
71 #include <sys/ktrace.h>
75 #include <vm/vm_param.h>
77 #include <vm/vm_page.h>
78 #include <vm/vm_map.h>
79 #include <vm/vm_kern.h>
80 #include <vm/vm_extern.h>
81 #include <vm/vm_object.h>
82 #include <vm/vm_pager.h>
85 #include <sys/pmckern.h>
88 #include <machine/reg.h>
90 #include <security/audit/audit.h>
91 #include <security/mac/mac_framework.h>
94 #include <sys/dtrace_bsd.h>
95 dtrace_execexit_func_t dtrace_fasttrap_exec;
98 SDT_PROVIDER_DECLARE(proc);
99 SDT_PROBE_DEFINE1(proc, kernel, , exec, exec, "char *");
100 SDT_PROBE_DEFINE1(proc, kernel, , exec_failure, exec-failure, "int");
101 SDT_PROBE_DEFINE1(proc, kernel, , exec_success, exec-success, "char *");
103 MALLOC_DEFINE(M_PARGS, "proc-args", "Process arguments");
105 static int sysctl_kern_ps_strings(SYSCTL_HANDLER_ARGS);
106 static int sysctl_kern_usrstack(SYSCTL_HANDLER_ARGS);
107 static int sysctl_kern_stackprot(SYSCTL_HANDLER_ARGS);
108 static int do_execve(struct thread *td, struct image_args *args,
111 /* XXX This should be vm_size_t. */
112 SYSCTL_PROC(_kern, KERN_PS_STRINGS, ps_strings, CTLTYPE_ULONG|CTLFLAG_RD,
113 NULL, 0, sysctl_kern_ps_strings, "LU", "");
115 /* XXX This should be vm_size_t. */
116 SYSCTL_PROC(_kern, KERN_USRSTACK, usrstack, CTLTYPE_ULONG|CTLFLAG_RD|
117 CTLFLAG_CAPRD, NULL, 0, sysctl_kern_usrstack, "LU", "");
119 SYSCTL_PROC(_kern, OID_AUTO, stackprot, CTLTYPE_INT|CTLFLAG_RD,
120 NULL, 0, sysctl_kern_stackprot, "I", "");
122 u_long ps_arg_cache_limit = PAGE_SIZE / 16;
123 SYSCTL_ULONG(_kern, OID_AUTO, ps_arg_cache_limit, CTLFLAG_RW,
124 &ps_arg_cache_limit, 0, "");
126 static int map_at_zero = 0;
127 TUNABLE_INT("security.bsd.map_at_zero", &map_at_zero);
128 SYSCTL_INT(_security_bsd, OID_AUTO, map_at_zero, CTLFLAG_RW, &map_at_zero, 0,
129 "Permit processes to map an object at virtual address 0.");
132 sysctl_kern_ps_strings(SYSCTL_HANDLER_ARGS)
139 if (req->flags & SCTL_MASK32) {
141 val = (unsigned int)p->p_sysent->sv_psstrings;
142 error = SYSCTL_OUT(req, &val, sizeof(val));
145 error = SYSCTL_OUT(req, &p->p_sysent->sv_psstrings,
146 sizeof(p->p_sysent->sv_psstrings));
151 sysctl_kern_usrstack(SYSCTL_HANDLER_ARGS)
158 if (req->flags & SCTL_MASK32) {
160 val = (unsigned int)p->p_sysent->sv_usrstack;
161 error = SYSCTL_OUT(req, &val, sizeof(val));
164 error = SYSCTL_OUT(req, &p->p_sysent->sv_usrstack,
165 sizeof(p->p_sysent->sv_usrstack));
170 sysctl_kern_stackprot(SYSCTL_HANDLER_ARGS)
175 return (SYSCTL_OUT(req, &p->p_sysent->sv_stackprot,
176 sizeof(p->p_sysent->sv_stackprot)));
180 * Each of the items is a pointer to a `const struct execsw', hence the
181 * double pointer here.
183 static const struct execsw **execsw;
185 #ifndef _SYS_SYSPROTO_H_
196 struct execve_args /* {
203 struct image_args args;
205 error = exec_copyin_args(&args, uap->fname, UIO_USERSPACE,
206 uap->argv, uap->envv);
208 error = kern_execve(td, &args, NULL);
212 #ifndef _SYS_SYSPROTO_H_
213 struct fexecve_args {
220 sys_fexecve(struct thread *td, struct fexecve_args *uap)
223 struct image_args args;
225 error = exec_copyin_args(&args, NULL, UIO_SYSSPACE,
226 uap->argv, uap->envv);
229 error = kern_execve(td, &args, NULL);
234 #ifndef _SYS_SYSPROTO_H_
235 struct __mac_execve_args {
244 sys___mac_execve(td, uap)
246 struct __mac_execve_args /* {
255 struct image_args args;
257 error = exec_copyin_args(&args, uap->fname, UIO_USERSPACE,
258 uap->argv, uap->envv);
260 error = kern_execve(td, &args, uap->mac_p);
268 * XXX: kern_execve has the astonishing property of not always returning to
269 * the caller. If sufficiently bad things happen during the call to
270 * do_execve(), it can end up calling exit1(); as a result, callers must
271 * avoid doing anything which they might need to undo (e.g., allocating
275 kern_execve(td, args, mac_p)
277 struct image_args *args;
280 struct proc *p = td->td_proc;
283 AUDIT_ARG_ARGV(args->begin_argv, args->argc,
284 args->begin_envv - args->begin_argv);
285 AUDIT_ARG_ENVV(args->begin_envv, args->envc,
286 args->endp - args->begin_envv);
287 if (p->p_flag & P_HADTHREADS) {
289 if (thread_single(SINGLE_BOUNDARY)) {
291 exec_free_args(args);
292 return (ERESTART); /* Try again later. */
297 error = do_execve(td, args, mac_p);
299 if (p->p_flag & P_HADTHREADS) {
302 * If success, we upgrade to SINGLE_EXIT state to
303 * force other threads to suicide.
306 thread_single(SINGLE_EXIT);
316 * In-kernel implementation of execve(). All arguments are assumed to be
317 * userspace pointers from the passed thread.
320 do_execve(td, args, mac_p)
322 struct image_args *args;
325 struct proc *p = td->td_proc;
327 struct ucred *newcred = NULL, *oldcred;
328 struct uidinfo *euip;
329 register_t *stack_base;
331 struct image_params image_params, *imgp;
333 int (*img_first)(struct image_params *);
334 struct pargs *oldargs = NULL, *newargs = NULL;
335 struct sigacts *oldsigacts, *newsigacts;
337 struct vnode *tracevp = NULL;
338 struct ucred *tracecred = NULL;
340 struct vnode *textvp = NULL, *binvp = NULL;
341 int credential_changing;
344 struct label *interpvplabel = NULL;
348 struct pmckern_procexec pe;
350 static const char fexecv_proc_title[] = "(fexecv)";
352 imgp = &image_params;
355 * Lock the process and set the P_INEXEC flag to indicate that
356 * it should be left alone until we're done here. This is
357 * necessary to avoid race conditions - e.g. in ptrace() -
358 * that might allow a local user to illicitly obtain elevated
362 KASSERT((p->p_flag & P_INEXEC) == 0,
363 ("%s(): process already has P_INEXEC flag", __func__));
364 p->p_flag |= P_INEXEC;
368 * Initialize part of the common data
371 imgp->execlabel = NULL;
373 imgp->entry_addr = 0;
374 imgp->reloc_base = 0;
375 imgp->vmspace_destroyed = 0;
376 imgp->interpreted = 0;
378 imgp->interpreter_name = NULL;
379 imgp->auxargs = NULL;
382 imgp->firstpage = NULL;
383 imgp->ps_strings = 0;
384 imgp->auxarg_size = 0;
386 imgp->execpath = imgp->freepath = NULL;
391 imgp->pagesizeslen = 0;
392 imgp->stack_prot = 0;
395 error = mac_execve_enter(imgp, mac_p);
400 imgp->image_header = NULL;
403 * Translate the file name. namei() returns a vnode pointer
404 * in ni_vp amoung other things.
406 * XXXAUDIT: It would be desirable to also audit the name of the
407 * interpreter if this is an interpreted binary.
409 if (args->fname != NULL) {
410 NDINIT(&nd, LOOKUP, ISOPEN | LOCKLEAF | FOLLOW | SAVENAME
411 | AUDITVNODE1, UIO_SYSSPACE, args->fname, td);
414 SDT_PROBE(proc, kernel, , exec, args->fname, 0, 0, 0, 0 );
417 if (args->fname != NULL) {
418 #ifdef CAPABILITY_MODE
420 * While capability mode can't reach this point via direct
421 * path arguments to execve(), we also don't allow
422 * interpreters to be used in capability mode (for now).
423 * Catch indirect lookups and return a permissions error.
425 if (IN_CAPABILITY_MODE(td)) {
437 AUDIT_ARG_FD(args->fd);
439 * Descriptors opened only with O_EXEC or O_RDONLY are allowed.
441 error = fgetvp_exec(td, args->fd, CAP_FEXECVE, &binvp);
444 vn_lock(binvp, LK_EXCLUSIVE | LK_RETRY);
445 AUDIT_ARG_VNODE1(binvp);
450 * Check file permissions (also 'opens' file)
452 error = exec_check_permissions(imgp);
454 goto exec_fail_dealloc;
456 imgp->object = imgp->vp->v_object;
457 if (imgp->object != NULL)
458 vm_object_reference(imgp->object);
461 * Set VV_TEXT now so no one can write to the executable while we're
464 * Remember if this was set before and unset it in case this is not
465 * actually an executable image.
467 textset = VOP_IS_TEXT(imgp->vp);
468 VOP_SET_TEXT(imgp->vp);
470 error = exec_map_first_page(imgp);
472 goto exec_fail_dealloc;
474 imgp->proc->p_osrel = 0;
476 * If the current process has a special image activator it
477 * wants to try first, call it. For example, emulating shell
478 * scripts differently.
481 if ((img_first = imgp->proc->p_sysent->sv_imgact_try) != NULL)
482 error = img_first(imgp);
485 * Loop through the list of image activators, calling each one.
486 * An activator returns -1 if there is no match, 0 on success,
487 * and an error otherwise.
489 for (i = 0; error == -1 && execsw[i]; ++i) {
490 if (execsw[i]->ex_imgact == NULL ||
491 execsw[i]->ex_imgact == img_first) {
494 error = (*execsw[i]->ex_imgact)(imgp);
500 VOP_UNSET_TEXT(imgp->vp);
503 goto exec_fail_dealloc;
507 * Special interpreter operation, cleanup and loop up to try to
508 * activate the interpreter.
510 if (imgp->interpreted) {
511 exec_unmap_first_page(imgp);
513 * VV_TEXT needs to be unset for scripts. There is a short
514 * period before we determine that something is a script where
515 * VV_TEXT will be set. The vnode lock is held over this
516 * entire period so nothing should illegitimately be blocked.
518 VOP_UNSET_TEXT(imgp->vp);
519 /* free name buffer and old vnode */
520 if (args->fname != NULL)
521 NDFREE(&nd, NDF_ONLY_PNBUF);
523 mac_execve_interpreter_enter(binvp, &interpvplabel);
526 VOP_CLOSE(binvp, FREAD, td->td_ucred, td);
530 vm_object_deallocate(imgp->object);
532 /* set new name to that of the interpreter */
533 NDINIT(&nd, LOOKUP, LOCKLEAF | FOLLOW | SAVENAME,
534 UIO_SYSSPACE, imgp->interpreter_name, td);
535 args->fname = imgp->interpreter_name;
540 * NB: We unlock the vnode here because it is believed that none
541 * of the sv_copyout_strings/sv_fixup operations require the vnode.
543 VOP_UNLOCK(imgp->vp, 0);
546 * Do the best to calculate the full path to the image file.
548 if (imgp->auxargs != NULL &&
549 ((args->fname != NULL && args->fname[0] == '/') ||
550 vn_fullpath(td, imgp->vp, &imgp->execpath, &imgp->freepath) != 0))
551 imgp->execpath = args->fname;
554 * Copy out strings (args and env) and initialize stack base
556 if (p->p_sysent->sv_copyout_strings)
557 stack_base = (*p->p_sysent->sv_copyout_strings)(imgp);
559 stack_base = exec_copyout_strings(imgp);
562 * If custom stack fixup routine present for this process
563 * let it do the stack setup.
564 * Else stuff argument count as first item on stack
566 if (p->p_sysent->sv_fixup != NULL)
567 (*p->p_sysent->sv_fixup)(&stack_base, imgp);
569 suword(--stack_base, imgp->args->argc);
572 * For security and other reasons, the file descriptor table cannot
573 * be shared after an exec.
578 * Malloc things before we need locks.
581 euip = uifind(attr.va_uid);
582 i = imgp->args->begin_envv - imgp->args->begin_argv;
583 /* Cache arguments if they fit inside our allowance */
584 if (ps_arg_cache_limit >= i + sizeof(struct pargs)) {
585 newargs = pargs_alloc(i);
586 bcopy(imgp->args->begin_argv, newargs->ar_args, i);
589 /* close files on exec */
591 vn_lock(imgp->vp, LK_SHARED | LK_RETRY);
593 /* Get a reference to the vnode prior to locking the proc */
597 * For security and other reasons, signal handlers cannot
598 * be shared after an exec. The new process gets a copy of the old
599 * handlers. In execsigs(), the new process will have its signals
603 oldcred = crcopysafe(p, newcred);
604 if (sigacts_shared(p->p_sigacts)) {
605 oldsigacts = p->p_sigacts;
607 newsigacts = sigacts_alloc();
608 sigacts_copy(newsigacts, oldsigacts);
610 p->p_sigacts = newsigacts;
617 /* reset caught signals */
620 /* name this process - nameiexec(p, ndp) */
621 bzero(p->p_comm, sizeof(p->p_comm));
623 bcopy(nd.ni_cnd.cn_nameptr, p->p_comm,
624 min(nd.ni_cnd.cn_namelen, MAXCOMLEN));
625 else if (vn_commname(binvp, p->p_comm, sizeof(p->p_comm)) != 0)
626 bcopy(fexecv_proc_title, p->p_comm, sizeof(fexecv_proc_title));
627 bcopy(p->p_comm, td->td_name, sizeof(td->td_name));
629 sched_clear_tdname(td);
633 * mark as execed, wakeup the process that vforked (if any) and tell
634 * it that it now has its own resources back
637 if (p->p_pptr && (p->p_flag & P_PPWAIT)) {
638 p->p_flag &= ~(P_PPWAIT | P_PPTRACE);
639 cv_broadcast(&p->p_pwait);
643 * Implement image setuid/setgid.
645 * Don't honor setuid/setgid if the filesystem prohibits it or if
646 * the process is being traced.
648 * We disable setuid/setgid/etc in compatibility mode on the basis
649 * that most setugid applications are not written with that
650 * environment in mind, and will therefore almost certainly operate
651 * incorrectly. In principle there's no reason that setugid
652 * applications might not be useful in capability mode, so we may want
653 * to reconsider this conservative design choice in the future.
655 * XXXMAC: For the time being, use NOSUID to also prohibit
656 * transitions on the file system.
658 credential_changing = 0;
659 credential_changing |= (attr.va_mode & S_ISUID) && oldcred->cr_uid !=
661 credential_changing |= (attr.va_mode & S_ISGID) && oldcred->cr_gid !=
664 will_transition = mac_vnode_execve_will_transition(oldcred, imgp->vp,
665 interpvplabel, imgp);
666 credential_changing |= will_transition;
669 if (credential_changing &&
670 #ifdef CAPABILITY_MODE
671 ((oldcred->cr_flags & CRED_FLAG_CAPMODE) == 0) &&
673 (imgp->vp->v_mount->mnt_flag & MNT_NOSUID) == 0 &&
674 (p->p_flag & P_TRACED) == 0) {
676 * Turn off syscall tracing for set-id programs, except for
677 * root. Record any set-id flags first to make sure that
678 * we do not regain any tracing during a possible block.
683 if (p->p_tracecred != NULL &&
684 priv_check_cred(p->p_tracecred, PRIV_DEBUG_DIFFCRED, 0))
685 ktrprocexec(p, &tracecred, &tracevp);
688 * Close any file descriptors 0..2 that reference procfs,
689 * then make sure file descriptors 0..2 are in use.
691 * setugidsafety() may call closef() and then pfind()
692 * which may grab the process lock.
693 * fdcheckstd() may call falloc() which may block to
694 * allocate memory, so temporarily drop the process lock.
697 VOP_UNLOCK(imgp->vp, 0);
699 error = fdcheckstd(td);
700 vn_lock(imgp->vp, LK_SHARED | LK_RETRY);
705 * Set the new credentials.
707 if (attr.va_mode & S_ISUID)
708 change_euid(newcred, euip);
709 if (attr.va_mode & S_ISGID)
710 change_egid(newcred, attr.va_gid);
712 if (will_transition) {
713 mac_vnode_execve_transition(oldcred, newcred, imgp->vp,
714 interpvplabel, imgp);
718 * Implement correct POSIX saved-id behavior.
720 * XXXMAC: Note that the current logic will save the
721 * uid and gid if a MAC domain transition occurs, even
722 * though maybe it shouldn't.
724 change_svuid(newcred, newcred->cr_uid);
725 change_svgid(newcred, newcred->cr_gid);
726 p->p_ucred = newcred;
729 if (oldcred->cr_uid == oldcred->cr_ruid &&
730 oldcred->cr_gid == oldcred->cr_rgid)
731 p->p_flag &= ~P_SUGID;
733 * Implement correct POSIX saved-id behavior.
735 * XXX: It's not clear that the existing behavior is
736 * POSIX-compliant. A number of sources indicate that the
737 * saved uid/gid should only be updated if the new ruid is
738 * not equal to the old ruid, or the new euid is not equal
739 * to the old euid and the new euid is not equal to the old
740 * ruid. The FreeBSD code always updates the saved uid/gid.
741 * Also, this code uses the new (replaced) euid and egid as
742 * the source, which may or may not be the right ones to use.
744 if (oldcred->cr_svuid != oldcred->cr_uid ||
745 oldcred->cr_svgid != oldcred->cr_gid) {
746 change_svuid(newcred, newcred->cr_uid);
747 change_svgid(newcred, newcred->cr_gid);
748 p->p_ucred = newcred;
754 * Store the vp for use in procfs. This vnode was referenced prior
755 * to locking the proc lock.
757 textvp = p->p_textvp;
762 * Tell the DTrace fasttrap provider about the exec if it
763 * has declared an interest.
765 if (dtrace_fasttrap_exec)
766 dtrace_fasttrap_exec(p);
770 * Notify others that we exec'd, and clear the P_INEXEC flag
771 * as we're now a bona fide freshly-execed process.
773 KNOTE_LOCKED(&p->p_klist, NOTE_EXEC);
774 p->p_flag &= ~P_INEXEC;
776 /* clear "fork but no exec" flag, as we _are_ execing */
777 p->p_acflag &= ~AFORK;
780 * Free any previous argument cache and replace it with
781 * the new argument cache, if any.
789 * Check if system-wide sampling is in effect or if the
790 * current process is using PMCs. If so, do exec() time
791 * processing. This processing needs to happen AFTER the
792 * P_INEXEC flag is cleared.
794 * The proc lock needs to be released before taking the PMC
797 if (PMC_SYSTEM_SAMPLING_ACTIVE() || PMC_PROC_IS_USING_PMCS(p)) {
799 VOP_UNLOCK(imgp->vp, 0);
800 pe.pm_credentialschanged = credential_changing;
801 pe.pm_entryaddr = imgp->entry_addr;
803 PMC_CALL_HOOK_X(td, PMC_FN_PROCESS_EXEC, (void *) &pe);
804 vn_lock(imgp->vp, LK_SHARED | LK_RETRY);
807 #else /* !HWPMC_HOOKS */
811 /* Set values passed into the program in registers. */
812 if (p->p_sysent->sv_setregs)
813 (*p->p_sysent->sv_setregs)(td, imgp,
814 (u_long)(uintptr_t)stack_base);
816 exec_setregs(td, imgp, (u_long)(uintptr_t)stack_base);
818 vfs_mark_atime(imgp->vp, td->td_ucred);
820 SDT_PROBE(proc, kernel, , exec_success, args->fname, 0, 0, 0, 0);
824 * Free any resources malloc'd earlier that we didn't use.
831 VOP_UNLOCK(imgp->vp, 0);
834 * Handle deferred decrement of ref counts.
838 if (binvp && error != 0)
843 if (tracecred != NULL)
846 vn_lock(imgp->vp, LK_SHARED | LK_RETRY);
849 if (oldsigacts != NULL)
850 sigacts_free(oldsigacts);
855 * free various allocated resources
857 if (imgp->firstpage != NULL)
858 exec_unmap_first_page(imgp);
860 if (imgp->vp != NULL) {
862 NDFREE(&nd, NDF_ONLY_PNBUF);
864 VOP_CLOSE(imgp->vp, FREAD, td->td_ucred, td);
868 if (imgp->object != NULL)
869 vm_object_deallocate(imgp->object);
871 free(imgp->freepath, M_TEMP);
875 td->td_dbgflags |= TDB_EXEC;
879 * Stop the process here if its stop event mask has
880 * the S_EXEC bit set.
882 STOPEVENT(p, S_EXEC, 0);
887 /* we're done here, clear P_INEXEC */
889 p->p_flag &= ~P_INEXEC;
892 SDT_PROBE(proc, kernel, , exec_failure, error, 0, 0, 0, 0);
896 mac_execve_exit(imgp);
897 mac_execve_interpreter_exit(interpvplabel);
899 exec_free_args(args);
901 if (error && imgp->vmspace_destroyed) {
902 /* sorry, no more process anymore. exit gracefully */
903 exit1(td, W_EXITCODE(0, SIGABRT));
916 exec_map_first_page(imgp)
917 struct image_params *imgp;
921 vm_page_t ma[VM_INITIAL_PAGEIN];
924 if (imgp->firstpage != NULL)
925 exec_unmap_first_page(imgp);
927 object = imgp->vp->v_object;
930 VM_OBJECT_WLOCK(object);
931 #if VM_NRESERVLEVEL > 0
932 if ((object->flags & OBJ_COLORED) == 0) {
933 object->flags |= OBJ_COLORED;
934 object->pg_color = 0;
937 ma[0] = vm_page_grab(object, 0, VM_ALLOC_NORMAL);
938 if (ma[0]->valid != VM_PAGE_BITS_ALL) {
939 initial_pagein = VM_INITIAL_PAGEIN;
940 if (initial_pagein > object->size)
941 initial_pagein = object->size;
942 for (i = 1; i < initial_pagein; i++) {
943 if ((ma[i] = vm_page_next(ma[i - 1])) != NULL) {
946 if (vm_page_tryxbusy(ma[i]))
949 ma[i] = vm_page_alloc(object, i,
950 VM_ALLOC_NORMAL | VM_ALLOC_IFNOTCACHED);
956 rv = vm_pager_get_pages(object, ma, initial_pagein, 0);
957 ma[0] = vm_page_lookup(object, 0);
958 if ((rv != VM_PAGER_OK) || (ma[0] == NULL)) {
962 vm_page_unlock(ma[0]);
964 VM_OBJECT_WUNLOCK(object);
968 vm_page_xunbusy(ma[0]);
971 vm_page_unlock(ma[0]);
972 VM_OBJECT_WUNLOCK(object);
974 imgp->firstpage = sf_buf_alloc(ma[0], 0);
975 imgp->image_header = (char *)sf_buf_kva(imgp->firstpage);
981 exec_unmap_first_page(imgp)
982 struct image_params *imgp;
986 if (imgp->firstpage != NULL) {
987 m = sf_buf_page(imgp->firstpage);
988 sf_buf_free(imgp->firstpage);
989 imgp->firstpage = NULL;
997 * Destroy old address space, and allocate a new stack
998 * The new stack is only SGROWSIZ large because it is grown
999 * automatically in trap.c.
1002 exec_new_vmspace(imgp, sv)
1003 struct image_params *imgp;
1004 struct sysentvec *sv;
1007 struct proc *p = imgp->proc;
1008 struct vmspace *vmspace = p->p_vmspace;
1010 vm_offset_t sv_minuser, stack_addr;
1014 imgp->vmspace_destroyed = 1;
1017 /* May be called with Giant held */
1018 EVENTHANDLER_INVOKE(process_exec, p, imgp);
1021 * Blow away entire process VM, if address space not shared,
1022 * otherwise, create a new VM space so that other threads are
1025 map = &vmspace->vm_map;
1027 sv_minuser = sv->sv_minuser;
1029 sv_minuser = MAX(sv->sv_minuser, PAGE_SIZE);
1030 if (vmspace->vm_refcnt == 1 && vm_map_min(map) == sv_minuser &&
1031 vm_map_max(map) == sv->sv_maxuser) {
1033 pmap_remove_pages(vmspace_pmap(vmspace));
1034 vm_map_remove(map, vm_map_min(map), vm_map_max(map));
1036 error = vmspace_exec(p, sv_minuser, sv->sv_maxuser);
1039 vmspace = p->p_vmspace;
1040 map = &vmspace->vm_map;
1043 /* Map a shared page */
1044 obj = sv->sv_shared_page_obj;
1046 vm_object_reference(obj);
1047 error = vm_map_fixed(map, obj, 0,
1048 sv->sv_shared_page_base, sv->sv_shared_page_len,
1049 VM_PROT_READ | VM_PROT_EXECUTE,
1050 VM_PROT_READ | VM_PROT_EXECUTE,
1051 MAP_INHERIT_SHARE | MAP_ACC_NO_CHARGE);
1053 vm_object_deallocate(obj);
1058 /* Allocate a new stack */
1059 if (sv->sv_maxssiz != NULL)
1060 ssiz = *sv->sv_maxssiz;
1063 stack_addr = sv->sv_usrstack - ssiz;
1064 error = vm_map_stack(map, stack_addr, (vm_size_t)ssiz,
1065 obj != NULL && imgp->stack_prot != 0 ? imgp->stack_prot :
1067 VM_PROT_ALL, MAP_STACK_GROWS_DOWN);
1072 /* Allocate a new register stack */
1073 stack_addr = IA64_BACKINGSTORE;
1074 error = vm_map_stack(map, stack_addr, (vm_size_t)ssiz,
1075 sv->sv_stackprot, VM_PROT_ALL, MAP_STACK_GROWS_UP);
1080 /* vm_ssize and vm_maxsaddr are somewhat antiquated concepts in the
1081 * VM_STACK case, but they are still used to monitor the size of the
1082 * process stack so we can check the stack rlimit.
1084 vmspace->vm_ssize = sgrowsiz >> PAGE_SHIFT;
1085 vmspace->vm_maxsaddr = (char *)sv->sv_usrstack - ssiz;
1091 * Copy out argument and environment strings from the old process address
1092 * space into the temporary string buffer.
1095 exec_copyin_args(struct image_args *args, char *fname,
1096 enum uio_seg segflg, char **argv, char **envv)
1102 bzero(args, sizeof(*args));
1107 * Allocate demand-paged memory for the file name, argument, and
1108 * environment strings.
1110 error = exec_alloc_args(args);
1115 * Copy the file name.
1117 if (fname != NULL) {
1118 args->fname = args->buf;
1119 error = (segflg == UIO_SYSSPACE) ?
1120 copystr(fname, args->fname, PATH_MAX, &length) :
1121 copyinstr(fname, args->fname, PATH_MAX, &length);
1127 args->begin_argv = args->buf + length;
1128 args->endp = args->begin_argv;
1129 args->stringspace = ARG_MAX;
1132 * extract arguments first
1134 while ((argp = (caddr_t) (intptr_t) fuword(argv++))) {
1135 if (argp == (caddr_t) -1) {
1139 if ((error = copyinstr(argp, args->endp,
1140 args->stringspace, &length))) {
1141 if (error == ENAMETOOLONG)
1145 args->stringspace -= length;
1146 args->endp += length;
1150 args->begin_envv = args->endp;
1153 * extract environment strings
1156 while ((envp = (caddr_t)(intptr_t)fuword(envv++))) {
1157 if (envp == (caddr_t)-1) {
1161 if ((error = copyinstr(envp, args->endp,
1162 args->stringspace, &length))) {
1163 if (error == ENAMETOOLONG)
1167 args->stringspace -= length;
1168 args->endp += length;
1176 exec_free_args(args);
1181 * Allocate temporary demand-paged, zero-filled memory for the file name,
1182 * argument, and environment strings. Returns zero if the allocation succeeds
1183 * and ENOMEM otherwise.
1186 exec_alloc_args(struct image_args *args)
1189 args->buf = (char *)kmap_alloc_wait(exec_map, PATH_MAX + ARG_MAX);
1190 return (args->buf != NULL ? 0 : ENOMEM);
1194 exec_free_args(struct image_args *args)
1197 if (args->buf != NULL) {
1198 kmap_free_wakeup(exec_map, (vm_offset_t)args->buf,
1199 PATH_MAX + ARG_MAX);
1202 if (args->fname_buf != NULL) {
1203 free(args->fname_buf, M_TEMP);
1204 args->fname_buf = NULL;
1209 * Copy strings out to the new process address space, constructing new arg
1210 * and env vector tables. Return a pointer to the base so that it can be used
1211 * as the initial stack pointer.
1214 exec_copyout_strings(imgp)
1215 struct image_params *imgp;
1219 char *stringp, *destp;
1220 register_t *stack_base;
1221 struct ps_strings *arginfo;
1223 size_t execpath_len;
1224 int szsigcode, szps;
1225 char canary[sizeof(long) * 8];
1227 szps = sizeof(pagesizes[0]) * MAXPAGESIZES;
1229 * Calculate string base and vector table pointers.
1230 * Also deal with signal trampoline code for this exec type.
1232 if (imgp->execpath != NULL && imgp->auxargs != NULL)
1233 execpath_len = strlen(imgp->execpath) + 1;
1238 arginfo = (struct ps_strings *)p->p_sysent->sv_psstrings;
1239 if (p->p_sysent->sv_sigcode_base == 0) {
1240 if (p->p_sysent->sv_szsigcode != NULL)
1241 szsigcode = *(p->p_sysent->sv_szsigcode);
1243 destp = (caddr_t)arginfo - szsigcode - SPARE_USRSPACE -
1244 roundup(execpath_len, sizeof(char *)) -
1245 roundup(sizeof(canary), sizeof(char *)) -
1246 roundup(szps, sizeof(char *)) -
1247 roundup((ARG_MAX - imgp->args->stringspace), sizeof(char *));
1253 copyout(p->p_sysent->sv_sigcode, ((caddr_t)arginfo -
1254 szsigcode), szsigcode);
1257 * Copy the image path for the rtld.
1259 if (execpath_len != 0) {
1260 imgp->execpathp = (uintptr_t)arginfo - szsigcode - execpath_len;
1261 copyout(imgp->execpath, (void *)imgp->execpathp,
1266 * Prepare the canary for SSP.
1268 arc4rand(canary, sizeof(canary), 0);
1269 imgp->canary = (uintptr_t)arginfo - szsigcode - execpath_len -
1271 copyout(canary, (void *)imgp->canary, sizeof(canary));
1272 imgp->canarylen = sizeof(canary);
1275 * Prepare the pagesizes array.
1277 imgp->pagesizes = (uintptr_t)arginfo - szsigcode - execpath_len -
1278 roundup(sizeof(canary), sizeof(char *)) - szps;
1279 copyout(pagesizes, (void *)imgp->pagesizes, szps);
1280 imgp->pagesizeslen = szps;
1283 * If we have a valid auxargs ptr, prepare some room
1286 if (imgp->auxargs) {
1288 * 'AT_COUNT*2' is size for the ELF Auxargs data. This is for
1289 * lower compatibility.
1291 imgp->auxarg_size = (imgp->auxarg_size) ? imgp->auxarg_size :
1294 * The '+ 2' is for the null pointers at the end of each of
1295 * the arg and env vector sets,and imgp->auxarg_size is room
1296 * for argument of Runtime loader.
1298 vectp = (char **)(destp - (imgp->args->argc +
1299 imgp->args->envc + 2 + imgp->auxarg_size)
1303 * The '+ 2' is for the null pointers at the end of each of
1304 * the arg and env vector sets
1306 vectp = (char **)(destp - (imgp->args->argc + imgp->args->envc + 2) *
1311 * vectp also becomes our initial stack base
1313 stack_base = (register_t *)vectp;
1315 stringp = imgp->args->begin_argv;
1316 argc = imgp->args->argc;
1317 envc = imgp->args->envc;
1320 * Copy out strings - arguments and environment.
1322 copyout(stringp, destp, ARG_MAX - imgp->args->stringspace);
1325 * Fill in "ps_strings" struct for ps, w, etc.
1327 suword(&arginfo->ps_argvstr, (long)(intptr_t)vectp);
1328 suword32(&arginfo->ps_nargvstr, argc);
1331 * Fill in argument portion of vector table.
1333 for (; argc > 0; --argc) {
1334 suword(vectp++, (long)(intptr_t)destp);
1335 while (*stringp++ != 0)
1340 /* a null vector table pointer separates the argp's from the envp's */
1343 suword(&arginfo->ps_envstr, (long)(intptr_t)vectp);
1344 suword32(&arginfo->ps_nenvstr, envc);
1347 * Fill in environment portion of vector table.
1349 for (; envc > 0; --envc) {
1350 suword(vectp++, (long)(intptr_t)destp);
1351 while (*stringp++ != 0)
1356 /* end of vector table is a null pointer */
1359 return (stack_base);
1363 * Check permissions of file to execute.
1364 * Called with imgp->vp locked.
1365 * Return 0 for success or error code on failure.
1368 exec_check_permissions(imgp)
1369 struct image_params *imgp;
1371 struct vnode *vp = imgp->vp;
1372 struct vattr *attr = imgp->attr;
1374 int error, writecount;
1378 /* Get file attributes */
1379 error = VOP_GETATTR(vp, attr, td->td_ucred);
1384 error = mac_vnode_check_exec(td->td_ucred, imgp->vp, imgp);
1390 * 1) Check if file execution is disabled for the filesystem that
1391 * this file resides on.
1392 * 2) Ensure that at least one execute bit is on. Otherwise, a
1393 * privileged user will always succeed, and we don't want this
1394 * to happen unless the file really is executable.
1395 * 3) Ensure that the file is a regular file.
1397 if ((vp->v_mount->mnt_flag & MNT_NOEXEC) ||
1398 (attr->va_mode & (S_IXUSR | S_IXGRP | S_IXOTH)) == 0 ||
1399 (attr->va_type != VREG))
1403 * Zero length files can't be exec'd
1405 if (attr->va_size == 0)
1409 * Check for execute permission to file based on current credentials.
1411 error = VOP_ACCESS(vp, VEXEC, td->td_ucred, td);
1416 * Check number of open-for-writes on the file and deny execution
1419 error = VOP_GET_WRITECOUNT(vp, &writecount);
1422 if (writecount != 0)
1426 * Call filesystem specific open routine (which does nothing in the
1429 error = VOP_OPEN(vp, FREAD, td->td_ucred, td, NULL);
1436 * Exec handler registration
1439 exec_register(execsw_arg)
1440 const struct execsw *execsw_arg;
1442 const struct execsw **es, **xs, **newexecsw;
1443 int count = 2; /* New slot and trailing NULL */
1446 for (es = execsw; *es; es++)
1448 newexecsw = malloc(count * sizeof(*es), M_TEMP, M_WAITOK);
1449 if (newexecsw == NULL)
1453 for (es = execsw; *es; es++)
1458 free(execsw, M_TEMP);
1464 exec_unregister(execsw_arg)
1465 const struct execsw *execsw_arg;
1467 const struct execsw **es, **xs, **newexecsw;
1471 panic("unregister with no handlers left?\n");
1473 for (es = execsw; *es; es++) {
1474 if (*es == execsw_arg)
1479 for (es = execsw; *es; es++)
1480 if (*es != execsw_arg)
1482 newexecsw = malloc(count * sizeof(*es), M_TEMP, M_WAITOK);
1483 if (newexecsw == NULL)
1486 for (es = execsw; *es; es++)
1487 if (*es != execsw_arg)
1491 free(execsw, M_TEMP);