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 disallow_high_osrel;
127 SYSCTL_INT(_kern, OID_AUTO, disallow_high_osrel, CTLFLAG_RW,
128 &disallow_high_osrel, 0,
129 "Disallow execution of binaries built for higher version of the world");
131 static int map_at_zero = 0;
132 TUNABLE_INT("security.bsd.map_at_zero", &map_at_zero);
133 SYSCTL_INT(_security_bsd, OID_AUTO, map_at_zero, CTLFLAG_RW, &map_at_zero, 0,
134 "Permit processes to map an object at virtual address 0.");
137 sysctl_kern_ps_strings(SYSCTL_HANDLER_ARGS)
144 if (req->flags & SCTL_MASK32) {
146 val = (unsigned int)p->p_sysent->sv_psstrings;
147 error = SYSCTL_OUT(req, &val, sizeof(val));
150 error = SYSCTL_OUT(req, &p->p_sysent->sv_psstrings,
151 sizeof(p->p_sysent->sv_psstrings));
156 sysctl_kern_usrstack(SYSCTL_HANDLER_ARGS)
163 if (req->flags & SCTL_MASK32) {
165 val = (unsigned int)p->p_sysent->sv_usrstack;
166 error = SYSCTL_OUT(req, &val, sizeof(val));
169 error = SYSCTL_OUT(req, &p->p_sysent->sv_usrstack,
170 sizeof(p->p_sysent->sv_usrstack));
175 sysctl_kern_stackprot(SYSCTL_HANDLER_ARGS)
180 return (SYSCTL_OUT(req, &p->p_sysent->sv_stackprot,
181 sizeof(p->p_sysent->sv_stackprot)));
185 * Each of the items is a pointer to a `const struct execsw', hence the
186 * double pointer here.
188 static const struct execsw **execsw;
190 #ifndef _SYS_SYSPROTO_H_
201 struct execve_args /* {
208 struct image_args args;
210 error = exec_copyin_args(&args, uap->fname, UIO_USERSPACE,
211 uap->argv, uap->envv);
213 error = kern_execve(td, &args, NULL);
217 #ifndef _SYS_SYSPROTO_H_
218 struct fexecve_args {
225 sys_fexecve(struct thread *td, struct fexecve_args *uap)
228 struct image_args args;
230 error = exec_copyin_args(&args, NULL, UIO_SYSSPACE,
231 uap->argv, uap->envv);
234 error = kern_execve(td, &args, NULL);
239 #ifndef _SYS_SYSPROTO_H_
240 struct __mac_execve_args {
249 sys___mac_execve(td, uap)
251 struct __mac_execve_args /* {
260 struct image_args args;
262 error = exec_copyin_args(&args, uap->fname, UIO_USERSPACE,
263 uap->argv, uap->envv);
265 error = kern_execve(td, &args, uap->mac_p);
273 * XXX: kern_execve has the astonishing property of not always returning to
274 * the caller. If sufficiently bad things happen during the call to
275 * do_execve(), it can end up calling exit1(); as a result, callers must
276 * avoid doing anything which they might need to undo (e.g., allocating
280 kern_execve(td, args, mac_p)
282 struct image_args *args;
285 struct proc *p = td->td_proc;
286 struct vmspace *oldvmspace;
289 AUDIT_ARG_ARGV(args->begin_argv, args->argc,
290 args->begin_envv - args->begin_argv);
291 AUDIT_ARG_ENVV(args->begin_envv, args->envc,
292 args->endp - args->begin_envv);
293 if (p->p_flag & P_HADTHREADS) {
295 if (thread_single(SINGLE_BOUNDARY)) {
297 exec_free_args(args);
298 return (ERESTART); /* Try again later. */
303 KASSERT((td->td_pflags & TDP_EXECVMSPC) == 0, ("nested execve"));
304 oldvmspace = td->td_proc->p_vmspace;
305 error = do_execve(td, args, mac_p);
307 if (p->p_flag & P_HADTHREADS) {
310 * If success, we upgrade to SINGLE_EXIT state to
311 * force other threads to suicide.
314 thread_single(SINGLE_EXIT);
319 if ((td->td_pflags & TDP_EXECVMSPC) != 0) {
320 KASSERT(td->td_proc->p_vmspace != oldvmspace,
321 ("oldvmspace still used"));
322 vmspace_free(oldvmspace);
323 td->td_pflags &= ~TDP_EXECVMSPC;
330 * In-kernel implementation of execve(). All arguments are assumed to be
331 * userspace pointers from the passed thread.
334 do_execve(td, args, mac_p)
336 struct image_args *args;
339 struct proc *p = td->td_proc;
341 struct ucred *newcred = NULL, *oldcred;
342 struct uidinfo *euip;
343 register_t *stack_base;
345 struct image_params image_params, *imgp;
347 int (*img_first)(struct image_params *);
348 struct pargs *oldargs = NULL, *newargs = NULL;
349 struct sigacts *oldsigacts, *newsigacts;
351 struct vnode *tracevp = NULL;
352 struct ucred *tracecred = NULL;
354 struct vnode *textvp = NULL, *binvp = NULL;
356 int credential_changing;
359 struct label *interpvplabel = NULL;
363 struct pmckern_procexec pe;
365 static const char fexecv_proc_title[] = "(fexecv)";
367 imgp = &image_params;
370 * Lock the process and set the P_INEXEC flag to indicate that
371 * it should be left alone until we're done here. This is
372 * necessary to avoid race conditions - e.g. in ptrace() -
373 * that might allow a local user to illicitly obtain elevated
377 KASSERT((p->p_flag & P_INEXEC) == 0,
378 ("%s(): process already has P_INEXEC flag", __func__));
379 p->p_flag |= P_INEXEC;
383 * Initialize part of the common data
386 imgp->execlabel = NULL;
388 imgp->entry_addr = 0;
389 imgp->reloc_base = 0;
390 imgp->vmspace_destroyed = 0;
391 imgp->interpreted = 0;
393 imgp->interpreter_name = NULL;
394 imgp->auxargs = NULL;
397 imgp->firstpage = NULL;
398 imgp->ps_strings = 0;
399 imgp->auxarg_size = 0;
401 imgp->execpath = imgp->freepath = NULL;
406 imgp->pagesizeslen = 0;
407 imgp->stack_prot = 0;
410 error = mac_execve_enter(imgp, mac_p);
415 imgp->image_header = NULL;
418 * Translate the file name. namei() returns a vnode pointer
419 * in ni_vp amoung other things.
421 * XXXAUDIT: It would be desirable to also audit the name of the
422 * interpreter if this is an interpreted binary.
424 if (args->fname != NULL) {
425 NDINIT(&nd, LOOKUP, ISOPEN | LOCKLEAF | FOLLOW | SAVENAME
426 | AUDITVNODE1, UIO_SYSSPACE, args->fname, td);
429 SDT_PROBE(proc, kernel, , exec, args->fname, 0, 0, 0, 0 );
432 if (args->fname != NULL) {
433 #ifdef CAPABILITY_MODE
435 * While capability mode can't reach this point via direct
436 * path arguments to execve(), we also don't allow
437 * interpreters to be used in capability mode (for now).
438 * Catch indirect lookups and return a permissions error.
440 if (IN_CAPABILITY_MODE(td)) {
452 AUDIT_ARG_FD(args->fd);
454 * Descriptors opened only with O_EXEC or O_RDONLY are allowed.
456 error = fgetvp_exec(td, args->fd,
457 cap_rights_init(&rights, CAP_FEXECVE), &binvp);
460 vn_lock(binvp, LK_EXCLUSIVE | LK_RETRY);
461 AUDIT_ARG_VNODE1(binvp);
466 * Check file permissions (also 'opens' file)
468 error = exec_check_permissions(imgp);
470 goto exec_fail_dealloc;
472 imgp->object = imgp->vp->v_object;
473 if (imgp->object != NULL)
474 vm_object_reference(imgp->object);
477 * Set VV_TEXT now so no one can write to the executable while we're
480 * Remember if this was set before and unset it in case this is not
481 * actually an executable image.
483 textset = VOP_IS_TEXT(imgp->vp);
484 VOP_SET_TEXT(imgp->vp);
486 error = exec_map_first_page(imgp);
488 goto exec_fail_dealloc;
490 imgp->proc->p_osrel = 0;
492 * If the current process has a special image activator it
493 * wants to try first, call it. For example, emulating shell
494 * scripts differently.
497 if ((img_first = imgp->proc->p_sysent->sv_imgact_try) != NULL)
498 error = img_first(imgp);
501 * Loop through the list of image activators, calling each one.
502 * An activator returns -1 if there is no match, 0 on success,
503 * and an error otherwise.
505 for (i = 0; error == -1 && execsw[i]; ++i) {
506 if (execsw[i]->ex_imgact == NULL ||
507 execsw[i]->ex_imgact == img_first) {
510 error = (*execsw[i]->ex_imgact)(imgp);
516 VOP_UNSET_TEXT(imgp->vp);
519 goto exec_fail_dealloc;
523 * Special interpreter operation, cleanup and loop up to try to
524 * activate the interpreter.
526 if (imgp->interpreted) {
527 exec_unmap_first_page(imgp);
529 * VV_TEXT needs to be unset for scripts. There is a short
530 * period before we determine that something is a script where
531 * VV_TEXT will be set. The vnode lock is held over this
532 * entire period so nothing should illegitimately be blocked.
534 VOP_UNSET_TEXT(imgp->vp);
535 /* free name buffer and old vnode */
536 if (args->fname != NULL)
537 NDFREE(&nd, NDF_ONLY_PNBUF);
539 mac_execve_interpreter_enter(binvp, &interpvplabel);
542 VOP_CLOSE(binvp, FREAD, td->td_ucred, td);
546 vm_object_deallocate(imgp->object);
548 /* set new name to that of the interpreter */
549 NDINIT(&nd, LOOKUP, LOCKLEAF | FOLLOW | SAVENAME,
550 UIO_SYSSPACE, imgp->interpreter_name, td);
551 args->fname = imgp->interpreter_name;
556 * NB: We unlock the vnode here because it is believed that none
557 * of the sv_copyout_strings/sv_fixup operations require the vnode.
559 VOP_UNLOCK(imgp->vp, 0);
562 * Do the best to calculate the full path to the image file.
564 if (imgp->auxargs != NULL &&
565 ((args->fname != NULL && args->fname[0] == '/') ||
566 vn_fullpath(td, imgp->vp, &imgp->execpath, &imgp->freepath) != 0))
567 imgp->execpath = args->fname;
569 if (disallow_high_osrel &&
570 P_OSREL_MAJOR(p->p_osrel) > P_OSREL_MAJOR(__FreeBSD_version)) {
572 uprintf("Osrel %d for image %s too high\n", p->p_osrel,
573 imgp->execpath != NULL ? imgp->execpath : "<unresolved>");
574 vn_lock(imgp->vp, LK_SHARED | LK_RETRY);
575 goto exec_fail_dealloc;
579 * Copy out strings (args and env) and initialize stack base
581 if (p->p_sysent->sv_copyout_strings)
582 stack_base = (*p->p_sysent->sv_copyout_strings)(imgp);
584 stack_base = exec_copyout_strings(imgp);
587 * If custom stack fixup routine present for this process
588 * let it do the stack setup.
589 * Else stuff argument count as first item on stack
591 if (p->p_sysent->sv_fixup != NULL)
592 (*p->p_sysent->sv_fixup)(&stack_base, imgp);
594 suword(--stack_base, imgp->args->argc);
597 * For security and other reasons, the file descriptor table cannot
598 * be shared after an exec.
603 * Malloc things before we need locks.
606 euip = uifind(attr.va_uid);
607 i = imgp->args->begin_envv - imgp->args->begin_argv;
608 /* Cache arguments if they fit inside our allowance */
609 if (ps_arg_cache_limit >= i + sizeof(struct pargs)) {
610 newargs = pargs_alloc(i);
611 bcopy(imgp->args->begin_argv, newargs->ar_args, i);
614 /* close files on exec */
616 vn_lock(imgp->vp, LK_SHARED | LK_RETRY);
618 /* Get a reference to the vnode prior to locking the proc */
622 * For security and other reasons, signal handlers cannot
623 * be shared after an exec. The new process gets a copy of the old
624 * handlers. In execsigs(), the new process will have its signals
628 oldcred = crcopysafe(p, newcred);
629 if (sigacts_shared(p->p_sigacts)) {
630 oldsigacts = p->p_sigacts;
632 newsigacts = sigacts_alloc();
633 sigacts_copy(newsigacts, oldsigacts);
635 p->p_sigacts = newsigacts;
642 /* reset caught signals */
645 /* name this process - nameiexec(p, ndp) */
646 bzero(p->p_comm, sizeof(p->p_comm));
648 bcopy(nd.ni_cnd.cn_nameptr, p->p_comm,
649 min(nd.ni_cnd.cn_namelen, MAXCOMLEN));
650 else if (vn_commname(binvp, p->p_comm, sizeof(p->p_comm)) != 0)
651 bcopy(fexecv_proc_title, p->p_comm, sizeof(fexecv_proc_title));
652 bcopy(p->p_comm, td->td_name, sizeof(td->td_name));
654 sched_clear_tdname(td);
658 * mark as execed, wakeup the process that vforked (if any) and tell
659 * it that it now has its own resources back
662 if (p->p_pptr && (p->p_flag & P_PPWAIT)) {
663 p->p_flag &= ~(P_PPWAIT | P_PPTRACE);
664 cv_broadcast(&p->p_pwait);
668 * Implement image setuid/setgid.
670 * Don't honor setuid/setgid if the filesystem prohibits it or if
671 * the process is being traced.
673 * We disable setuid/setgid/etc in compatibility mode on the basis
674 * that most setugid applications are not written with that
675 * environment in mind, and will therefore almost certainly operate
676 * incorrectly. In principle there's no reason that setugid
677 * applications might not be useful in capability mode, so we may want
678 * to reconsider this conservative design choice in the future.
680 * XXXMAC: For the time being, use NOSUID to also prohibit
681 * transitions on the file system.
683 credential_changing = 0;
684 credential_changing |= (attr.va_mode & S_ISUID) && oldcred->cr_uid !=
686 credential_changing |= (attr.va_mode & S_ISGID) && oldcred->cr_gid !=
689 will_transition = mac_vnode_execve_will_transition(oldcred, imgp->vp,
690 interpvplabel, imgp);
691 credential_changing |= will_transition;
694 if (credential_changing &&
695 #ifdef CAPABILITY_MODE
696 ((oldcred->cr_flags & CRED_FLAG_CAPMODE) == 0) &&
698 (imgp->vp->v_mount->mnt_flag & MNT_NOSUID) == 0 &&
699 (p->p_flag & P_TRACED) == 0) {
701 * Turn off syscall tracing for set-id programs, except for
702 * root. Record any set-id flags first to make sure that
703 * we do not regain any tracing during a possible block.
708 if (p->p_tracecred != NULL &&
709 priv_check_cred(p->p_tracecred, PRIV_DEBUG_DIFFCRED, 0))
710 ktrprocexec(p, &tracecred, &tracevp);
713 * Close any file descriptors 0..2 that reference procfs,
714 * then make sure file descriptors 0..2 are in use.
716 * setugidsafety() may call closef() and then pfind()
717 * which may grab the process lock.
718 * fdcheckstd() may call falloc() which may block to
719 * allocate memory, so temporarily drop the process lock.
722 VOP_UNLOCK(imgp->vp, 0);
724 error = fdcheckstd(td);
725 vn_lock(imgp->vp, LK_SHARED | LK_RETRY);
730 * Set the new credentials.
732 if (attr.va_mode & S_ISUID)
733 change_euid(newcred, euip);
734 if (attr.va_mode & S_ISGID)
735 change_egid(newcred, attr.va_gid);
737 if (will_transition) {
738 mac_vnode_execve_transition(oldcred, newcred, imgp->vp,
739 interpvplabel, imgp);
743 * Implement correct POSIX saved-id behavior.
745 * XXXMAC: Note that the current logic will save the
746 * uid and gid if a MAC domain transition occurs, even
747 * though maybe it shouldn't.
749 change_svuid(newcred, newcred->cr_uid);
750 change_svgid(newcred, newcred->cr_gid);
751 p->p_ucred = newcred;
754 if (oldcred->cr_uid == oldcred->cr_ruid &&
755 oldcred->cr_gid == oldcred->cr_rgid)
756 p->p_flag &= ~P_SUGID;
758 * Implement correct POSIX saved-id behavior.
760 * XXX: It's not clear that the existing behavior is
761 * POSIX-compliant. A number of sources indicate that the
762 * saved uid/gid should only be updated if the new ruid is
763 * not equal to the old ruid, or the new euid is not equal
764 * to the old euid and the new euid is not equal to the old
765 * ruid. The FreeBSD code always updates the saved uid/gid.
766 * Also, this code uses the new (replaced) euid and egid as
767 * the source, which may or may not be the right ones to use.
769 if (oldcred->cr_svuid != oldcred->cr_uid ||
770 oldcred->cr_svgid != oldcred->cr_gid) {
771 change_svuid(newcred, newcred->cr_uid);
772 change_svgid(newcred, newcred->cr_gid);
773 p->p_ucred = newcred;
779 * Store the vp for use in procfs. This vnode was referenced prior
780 * to locking the proc lock.
782 textvp = p->p_textvp;
787 * Tell the DTrace fasttrap provider about the exec if it
788 * has declared an interest.
790 if (dtrace_fasttrap_exec)
791 dtrace_fasttrap_exec(p);
795 * Notify others that we exec'd, and clear the P_INEXEC flag
796 * as we're now a bona fide freshly-execed process.
798 KNOTE_LOCKED(&p->p_klist, NOTE_EXEC);
799 p->p_flag &= ~P_INEXEC;
801 /* clear "fork but no exec" flag, as we _are_ execing */
802 p->p_acflag &= ~AFORK;
805 * Free any previous argument cache and replace it with
806 * the new argument cache, if any.
814 * Check if system-wide sampling is in effect or if the
815 * current process is using PMCs. If so, do exec() time
816 * processing. This processing needs to happen AFTER the
817 * P_INEXEC flag is cleared.
819 * The proc lock needs to be released before taking the PMC
822 if (PMC_SYSTEM_SAMPLING_ACTIVE() || PMC_PROC_IS_USING_PMCS(p)) {
824 VOP_UNLOCK(imgp->vp, 0);
825 pe.pm_credentialschanged = credential_changing;
826 pe.pm_entryaddr = imgp->entry_addr;
828 PMC_CALL_HOOK_X(td, PMC_FN_PROCESS_EXEC, (void *) &pe);
829 vn_lock(imgp->vp, LK_SHARED | LK_RETRY);
832 #else /* !HWPMC_HOOKS */
836 /* Set values passed into the program in registers. */
837 if (p->p_sysent->sv_setregs)
838 (*p->p_sysent->sv_setregs)(td, imgp,
839 (u_long)(uintptr_t)stack_base);
841 exec_setregs(td, imgp, (u_long)(uintptr_t)stack_base);
843 vfs_mark_atime(imgp->vp, td->td_ucred);
845 SDT_PROBE(proc, kernel, , exec_success, args->fname, 0, 0, 0, 0);
849 * Free any resources malloc'd earlier that we didn't use.
856 VOP_UNLOCK(imgp->vp, 0);
859 * Handle deferred decrement of ref counts.
863 if (binvp && error != 0)
868 if (tracecred != NULL)
871 vn_lock(imgp->vp, LK_SHARED | LK_RETRY);
874 if (oldsigacts != NULL)
875 sigacts_free(oldsigacts);
880 * free various allocated resources
882 if (imgp->firstpage != NULL)
883 exec_unmap_first_page(imgp);
885 if (imgp->vp != NULL) {
887 NDFREE(&nd, NDF_ONLY_PNBUF);
889 VOP_CLOSE(imgp->vp, FREAD, td->td_ucred, td);
893 if (imgp->object != NULL)
894 vm_object_deallocate(imgp->object);
896 free(imgp->freepath, M_TEMP);
900 td->td_dbgflags |= TDB_EXEC;
904 * Stop the process here if its stop event mask has
905 * the S_EXEC bit set.
907 STOPEVENT(p, S_EXEC, 0);
912 /* we're done here, clear P_INEXEC */
914 p->p_flag &= ~P_INEXEC;
917 SDT_PROBE(proc, kernel, , exec_failure, error, 0, 0, 0, 0);
921 mac_execve_exit(imgp);
922 mac_execve_interpreter_exit(interpvplabel);
924 exec_free_args(args);
926 if (error && imgp->vmspace_destroyed) {
927 /* sorry, no more process anymore. exit gracefully */
928 exit1(td, W_EXITCODE(0, SIGABRT));
941 exec_map_first_page(imgp)
942 struct image_params *imgp;
946 vm_page_t ma[VM_INITIAL_PAGEIN];
949 if (imgp->firstpage != NULL)
950 exec_unmap_first_page(imgp);
952 object = imgp->vp->v_object;
955 VM_OBJECT_WLOCK(object);
956 #if VM_NRESERVLEVEL > 0
957 if ((object->flags & OBJ_COLORED) == 0) {
958 object->flags |= OBJ_COLORED;
959 object->pg_color = 0;
962 ma[0] = vm_page_grab(object, 0, VM_ALLOC_NORMAL);
963 if (ma[0]->valid != VM_PAGE_BITS_ALL) {
964 initial_pagein = VM_INITIAL_PAGEIN;
965 if (initial_pagein > object->size)
966 initial_pagein = object->size;
967 for (i = 1; i < initial_pagein; i++) {
968 if ((ma[i] = vm_page_next(ma[i - 1])) != NULL) {
971 if (vm_page_tryxbusy(ma[i]))
974 ma[i] = vm_page_alloc(object, i,
975 VM_ALLOC_NORMAL | VM_ALLOC_IFNOTCACHED);
981 rv = vm_pager_get_pages(object, ma, initial_pagein, 0);
982 ma[0] = vm_page_lookup(object, 0);
983 if ((rv != VM_PAGER_OK) || (ma[0] == NULL)) {
987 vm_page_unlock(ma[0]);
989 VM_OBJECT_WUNLOCK(object);
993 vm_page_xunbusy(ma[0]);
996 vm_page_unlock(ma[0]);
997 VM_OBJECT_WUNLOCK(object);
999 imgp->firstpage = sf_buf_alloc(ma[0], 0);
1000 imgp->image_header = (char *)sf_buf_kva(imgp->firstpage);
1006 exec_unmap_first_page(imgp)
1007 struct image_params *imgp;
1011 if (imgp->firstpage != NULL) {
1012 m = sf_buf_page(imgp->firstpage);
1013 sf_buf_free(imgp->firstpage);
1014 imgp->firstpage = NULL;
1022 * Destroy old address space, and allocate a new stack
1023 * The new stack is only SGROWSIZ large because it is grown
1024 * automatically in trap.c.
1027 exec_new_vmspace(imgp, sv)
1028 struct image_params *imgp;
1029 struct sysentvec *sv;
1032 struct proc *p = imgp->proc;
1033 struct vmspace *vmspace = p->p_vmspace;
1035 vm_offset_t sv_minuser, stack_addr;
1039 imgp->vmspace_destroyed = 1;
1042 /* May be called with Giant held */
1043 EVENTHANDLER_INVOKE(process_exec, p, imgp);
1046 * Blow away entire process VM, if address space not shared,
1047 * otherwise, create a new VM space so that other threads are
1050 map = &vmspace->vm_map;
1052 sv_minuser = sv->sv_minuser;
1054 sv_minuser = MAX(sv->sv_minuser, PAGE_SIZE);
1055 if (vmspace->vm_refcnt == 1 && vm_map_min(map) == sv_minuser &&
1056 vm_map_max(map) == sv->sv_maxuser) {
1058 pmap_remove_pages(vmspace_pmap(vmspace));
1059 vm_map_remove(map, vm_map_min(map), vm_map_max(map));
1061 error = vmspace_exec(p, sv_minuser, sv->sv_maxuser);
1064 vmspace = p->p_vmspace;
1065 map = &vmspace->vm_map;
1068 /* Map a shared page */
1069 obj = sv->sv_shared_page_obj;
1071 vm_object_reference(obj);
1072 error = vm_map_fixed(map, obj, 0,
1073 sv->sv_shared_page_base, sv->sv_shared_page_len,
1074 VM_PROT_READ | VM_PROT_EXECUTE,
1075 VM_PROT_READ | VM_PROT_EXECUTE,
1076 MAP_INHERIT_SHARE | MAP_ACC_NO_CHARGE);
1078 vm_object_deallocate(obj);
1083 /* Allocate a new stack */
1084 if (sv->sv_maxssiz != NULL)
1085 ssiz = *sv->sv_maxssiz;
1088 stack_addr = sv->sv_usrstack - ssiz;
1089 error = vm_map_stack(map, stack_addr, (vm_size_t)ssiz,
1090 obj != NULL && imgp->stack_prot != 0 ? imgp->stack_prot :
1092 VM_PROT_ALL, MAP_STACK_GROWS_DOWN);
1097 /* Allocate a new register stack */
1098 stack_addr = IA64_BACKINGSTORE;
1099 error = vm_map_stack(map, stack_addr, (vm_size_t)ssiz,
1100 sv->sv_stackprot, VM_PROT_ALL, MAP_STACK_GROWS_UP);
1105 /* vm_ssize and vm_maxsaddr are somewhat antiquated concepts in the
1106 * VM_STACK case, but they are still used to monitor the size of the
1107 * process stack so we can check the stack rlimit.
1109 vmspace->vm_ssize = sgrowsiz >> PAGE_SHIFT;
1110 vmspace->vm_maxsaddr = (char *)sv->sv_usrstack - ssiz;
1116 * Copy out argument and environment strings from the old process address
1117 * space into the temporary string buffer.
1120 exec_copyin_args(struct image_args *args, char *fname,
1121 enum uio_seg segflg, char **argv, char **envv)
1127 bzero(args, sizeof(*args));
1132 * Allocate demand-paged memory for the file name, argument, and
1133 * environment strings.
1135 error = exec_alloc_args(args);
1140 * Copy the file name.
1142 if (fname != NULL) {
1143 args->fname = args->buf;
1144 error = (segflg == UIO_SYSSPACE) ?
1145 copystr(fname, args->fname, PATH_MAX, &length) :
1146 copyinstr(fname, args->fname, PATH_MAX, &length);
1152 args->begin_argv = args->buf + length;
1153 args->endp = args->begin_argv;
1154 args->stringspace = ARG_MAX;
1157 * extract arguments first
1159 while ((argp = (caddr_t) (intptr_t) fuword(argv++))) {
1160 if (argp == (caddr_t) -1) {
1164 if ((error = copyinstr(argp, args->endp,
1165 args->stringspace, &length))) {
1166 if (error == ENAMETOOLONG)
1170 args->stringspace -= length;
1171 args->endp += length;
1175 args->begin_envv = args->endp;
1178 * extract environment strings
1181 while ((envp = (caddr_t)(intptr_t)fuword(envv++))) {
1182 if (envp == (caddr_t)-1) {
1186 if ((error = copyinstr(envp, args->endp,
1187 args->stringspace, &length))) {
1188 if (error == ENAMETOOLONG)
1192 args->stringspace -= length;
1193 args->endp += length;
1201 exec_free_args(args);
1206 * Allocate temporary demand-paged, zero-filled memory for the file name,
1207 * argument, and environment strings. Returns zero if the allocation succeeds
1208 * and ENOMEM otherwise.
1211 exec_alloc_args(struct image_args *args)
1214 args->buf = (char *)kmap_alloc_wait(exec_map, PATH_MAX + ARG_MAX);
1215 return (args->buf != NULL ? 0 : ENOMEM);
1219 exec_free_args(struct image_args *args)
1222 if (args->buf != NULL) {
1223 kmap_free_wakeup(exec_map, (vm_offset_t)args->buf,
1224 PATH_MAX + ARG_MAX);
1227 if (args->fname_buf != NULL) {
1228 free(args->fname_buf, M_TEMP);
1229 args->fname_buf = NULL;
1234 * Copy strings out to the new process address space, constructing new arg
1235 * and env vector tables. Return a pointer to the base so that it can be used
1236 * as the initial stack pointer.
1239 exec_copyout_strings(imgp)
1240 struct image_params *imgp;
1244 char *stringp, *destp;
1245 register_t *stack_base;
1246 struct ps_strings *arginfo;
1248 size_t execpath_len;
1249 int szsigcode, szps;
1250 char canary[sizeof(long) * 8];
1252 szps = sizeof(pagesizes[0]) * MAXPAGESIZES;
1254 * Calculate string base and vector table pointers.
1255 * Also deal with signal trampoline code for this exec type.
1257 if (imgp->execpath != NULL && imgp->auxargs != NULL)
1258 execpath_len = strlen(imgp->execpath) + 1;
1263 arginfo = (struct ps_strings *)p->p_sysent->sv_psstrings;
1264 if (p->p_sysent->sv_sigcode_base == 0) {
1265 if (p->p_sysent->sv_szsigcode != NULL)
1266 szsigcode = *(p->p_sysent->sv_szsigcode);
1268 destp = (caddr_t)arginfo - szsigcode - SPARE_USRSPACE -
1269 roundup(execpath_len, sizeof(char *)) -
1270 roundup(sizeof(canary), sizeof(char *)) -
1271 roundup(szps, sizeof(char *)) -
1272 roundup((ARG_MAX - imgp->args->stringspace), sizeof(char *));
1278 copyout(p->p_sysent->sv_sigcode, ((caddr_t)arginfo -
1279 szsigcode), szsigcode);
1282 * Copy the image path for the rtld.
1284 if (execpath_len != 0) {
1285 imgp->execpathp = (uintptr_t)arginfo - szsigcode - execpath_len;
1286 copyout(imgp->execpath, (void *)imgp->execpathp,
1291 * Prepare the canary for SSP.
1293 arc4rand(canary, sizeof(canary), 0);
1294 imgp->canary = (uintptr_t)arginfo - szsigcode - execpath_len -
1296 copyout(canary, (void *)imgp->canary, sizeof(canary));
1297 imgp->canarylen = sizeof(canary);
1300 * Prepare the pagesizes array.
1302 imgp->pagesizes = (uintptr_t)arginfo - szsigcode - execpath_len -
1303 roundup(sizeof(canary), sizeof(char *)) - szps;
1304 copyout(pagesizes, (void *)imgp->pagesizes, szps);
1305 imgp->pagesizeslen = szps;
1308 * If we have a valid auxargs ptr, prepare some room
1311 if (imgp->auxargs) {
1313 * 'AT_COUNT*2' is size for the ELF Auxargs data. This is for
1314 * lower compatibility.
1316 imgp->auxarg_size = (imgp->auxarg_size) ? imgp->auxarg_size :
1319 * The '+ 2' is for the null pointers at the end of each of
1320 * the arg and env vector sets,and imgp->auxarg_size is room
1321 * for argument of Runtime loader.
1323 vectp = (char **)(destp - (imgp->args->argc +
1324 imgp->args->envc + 2 + imgp->auxarg_size)
1328 * The '+ 2' is for the null pointers at the end of each of
1329 * the arg and env vector sets
1331 vectp = (char **)(destp - (imgp->args->argc + imgp->args->envc + 2) *
1336 * vectp also becomes our initial stack base
1338 stack_base = (register_t *)vectp;
1340 stringp = imgp->args->begin_argv;
1341 argc = imgp->args->argc;
1342 envc = imgp->args->envc;
1345 * Copy out strings - arguments and environment.
1347 copyout(stringp, destp, ARG_MAX - imgp->args->stringspace);
1350 * Fill in "ps_strings" struct for ps, w, etc.
1352 suword(&arginfo->ps_argvstr, (long)(intptr_t)vectp);
1353 suword32(&arginfo->ps_nargvstr, argc);
1356 * Fill in argument portion of vector table.
1358 for (; argc > 0; --argc) {
1359 suword(vectp++, (long)(intptr_t)destp);
1360 while (*stringp++ != 0)
1365 /* a null vector table pointer separates the argp's from the envp's */
1368 suword(&arginfo->ps_envstr, (long)(intptr_t)vectp);
1369 suword32(&arginfo->ps_nenvstr, envc);
1372 * Fill in environment portion of vector table.
1374 for (; envc > 0; --envc) {
1375 suword(vectp++, (long)(intptr_t)destp);
1376 while (*stringp++ != 0)
1381 /* end of vector table is a null pointer */
1384 return (stack_base);
1388 * Check permissions of file to execute.
1389 * Called with imgp->vp locked.
1390 * Return 0 for success or error code on failure.
1393 exec_check_permissions(imgp)
1394 struct image_params *imgp;
1396 struct vnode *vp = imgp->vp;
1397 struct vattr *attr = imgp->attr;
1399 int error, writecount;
1403 /* Get file attributes */
1404 error = VOP_GETATTR(vp, attr, td->td_ucred);
1409 error = mac_vnode_check_exec(td->td_ucred, imgp->vp, imgp);
1415 * 1) Check if file execution is disabled for the filesystem that
1416 * this file resides on.
1417 * 2) Ensure that at least one execute bit is on. Otherwise, a
1418 * privileged user will always succeed, and we don't want this
1419 * to happen unless the file really is executable.
1420 * 3) Ensure that the file is a regular file.
1422 if ((vp->v_mount->mnt_flag & MNT_NOEXEC) ||
1423 (attr->va_mode & (S_IXUSR | S_IXGRP | S_IXOTH)) == 0 ||
1424 (attr->va_type != VREG))
1428 * Zero length files can't be exec'd
1430 if (attr->va_size == 0)
1434 * Check for execute permission to file based on current credentials.
1436 error = VOP_ACCESS(vp, VEXEC, td->td_ucred, td);
1441 * Check number of open-for-writes on the file and deny execution
1444 error = VOP_GET_WRITECOUNT(vp, &writecount);
1447 if (writecount != 0)
1451 * Call filesystem specific open routine (which does nothing in the
1454 error = VOP_OPEN(vp, FREAD, td->td_ucred, td, NULL);
1461 * Exec handler registration
1464 exec_register(execsw_arg)
1465 const struct execsw *execsw_arg;
1467 const struct execsw **es, **xs, **newexecsw;
1468 int count = 2; /* New slot and trailing NULL */
1471 for (es = execsw; *es; es++)
1473 newexecsw = malloc(count * sizeof(*es), M_TEMP, M_WAITOK);
1474 if (newexecsw == NULL)
1478 for (es = execsw; *es; es++)
1483 free(execsw, M_TEMP);
1489 exec_unregister(execsw_arg)
1490 const struct execsw *execsw_arg;
1492 const struct execsw **es, **xs, **newexecsw;
1496 panic("unregister with no handlers left?\n");
1498 for (es = execsw; *es; es++) {
1499 if (*es == execsw_arg)
1504 for (es = execsw; *es; es++)
1505 if (*es != execsw_arg)
1507 newexecsw = malloc(count * sizeof(*es), M_TEMP, M_WAITOK);
1508 if (newexecsw == NULL)
1511 for (es = execsw; *es; es++)
1512 if (*es != execsw_arg)
1516 free(execsw, M_TEMP);