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/capsicum.h>
38 #include <sys/systm.h>
39 #include <sys/capsicum.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, "char *");
100 SDT_PROBE_DEFINE1(proc, kernel, , exec__failure, "int");
101 SDT_PROBE_DEFINE1(proc, kernel, , exec__success, "char *");
103 MALLOC_DEFINE(M_PARGS, "proc-args", "Process arguments");
105 int coredump_pack_fileinfo = 1;
106 SYSCTL_INT(_kern, OID_AUTO, coredump_pack_fileinfo, CTLFLAG_RWTUN,
107 &coredump_pack_fileinfo, 0,
108 "Enable file path packing in 'procstat -f' coredump notes");
110 int coredump_pack_vmmapinfo = 1;
111 SYSCTL_INT(_kern, OID_AUTO, coredump_pack_vmmapinfo, CTLFLAG_RWTUN,
112 &coredump_pack_vmmapinfo, 0,
113 "Enable file path packing in 'procstat -v' coredump notes");
115 static int sysctl_kern_ps_strings(SYSCTL_HANDLER_ARGS);
116 static int sysctl_kern_usrstack(SYSCTL_HANDLER_ARGS);
117 static int sysctl_kern_stackprot(SYSCTL_HANDLER_ARGS);
118 static int do_execve(struct thread *td, struct image_args *args,
121 /* XXX This should be vm_size_t. */
122 SYSCTL_PROC(_kern, KERN_PS_STRINGS, ps_strings, CTLTYPE_ULONG|CTLFLAG_RD,
123 NULL, 0, sysctl_kern_ps_strings, "LU", "");
125 /* XXX This should be vm_size_t. */
126 SYSCTL_PROC(_kern, KERN_USRSTACK, usrstack, CTLTYPE_ULONG|CTLFLAG_RD|
127 CTLFLAG_CAPRD, NULL, 0, sysctl_kern_usrstack, "LU", "");
129 SYSCTL_PROC(_kern, OID_AUTO, stackprot, CTLTYPE_INT|CTLFLAG_RD,
130 NULL, 0, sysctl_kern_stackprot, "I", "");
132 u_long ps_arg_cache_limit = PAGE_SIZE / 16;
133 SYSCTL_ULONG(_kern, OID_AUTO, ps_arg_cache_limit, CTLFLAG_RW,
134 &ps_arg_cache_limit, 0, "");
136 static int disallow_high_osrel;
137 SYSCTL_INT(_kern, OID_AUTO, disallow_high_osrel, CTLFLAG_RW,
138 &disallow_high_osrel, 0,
139 "Disallow execution of binaries built for higher version of the world");
141 static int map_at_zero = 0;
142 TUNABLE_INT("security.bsd.map_at_zero", &map_at_zero);
143 SYSCTL_INT(_security_bsd, OID_AUTO, map_at_zero, CTLFLAG_RW, &map_at_zero, 0,
144 "Permit processes to map an object at virtual address 0.");
147 sysctl_kern_ps_strings(SYSCTL_HANDLER_ARGS)
154 if (req->flags & SCTL_MASK32) {
156 val = (unsigned int)p->p_sysent->sv_psstrings;
157 error = SYSCTL_OUT(req, &val, sizeof(val));
160 error = SYSCTL_OUT(req, &p->p_sysent->sv_psstrings,
161 sizeof(p->p_sysent->sv_psstrings));
166 sysctl_kern_usrstack(SYSCTL_HANDLER_ARGS)
173 if (req->flags & SCTL_MASK32) {
175 val = (unsigned int)p->p_sysent->sv_usrstack;
176 error = SYSCTL_OUT(req, &val, sizeof(val));
179 error = SYSCTL_OUT(req, &p->p_sysent->sv_usrstack,
180 sizeof(p->p_sysent->sv_usrstack));
185 sysctl_kern_stackprot(SYSCTL_HANDLER_ARGS)
190 return (SYSCTL_OUT(req, &p->p_sysent->sv_stackprot,
191 sizeof(p->p_sysent->sv_stackprot)));
195 * Each of the items is a pointer to a `const struct execsw', hence the
196 * double pointer here.
198 static const struct execsw **execsw;
200 #ifndef _SYS_SYSPROTO_H_
209 sys_execve(struct thread *td, struct execve_args *uap)
211 struct image_args args;
212 struct vmspace *oldvmspace;
215 error = pre_execve(td, &oldvmspace);
218 error = exec_copyin_args(&args, uap->fname, UIO_USERSPACE,
219 uap->argv, uap->envv);
221 error = kern_execve(td, &args, NULL);
222 post_execve(td, error, oldvmspace);
226 #ifndef _SYS_SYSPROTO_H_
227 struct fexecve_args {
234 sys_fexecve(struct thread *td, struct fexecve_args *uap)
236 struct image_args args;
237 struct vmspace *oldvmspace;
240 error = pre_execve(td, &oldvmspace);
243 error = exec_copyin_args(&args, NULL, UIO_SYSSPACE,
244 uap->argv, uap->envv);
247 error = kern_execve(td, &args, NULL);
249 post_execve(td, error, oldvmspace);
253 #ifndef _SYS_SYSPROTO_H_
254 struct __mac_execve_args {
263 sys___mac_execve(struct thread *td, struct __mac_execve_args *uap)
266 struct image_args args;
267 struct vmspace *oldvmspace;
270 error = pre_execve(td, &oldvmspace);
273 error = exec_copyin_args(&args, uap->fname, UIO_USERSPACE,
274 uap->argv, uap->envv);
276 error = kern_execve(td, &args, uap->mac_p);
277 post_execve(td, error, oldvmspace);
285 pre_execve(struct thread *td, struct vmspace **oldvmspace)
290 KASSERT(td == curthread, ("non-current thread %p", td));
293 if ((p->p_flag & P_HADTHREADS) != 0) {
295 if (thread_single(p, SINGLE_BOUNDARY) != 0)
299 KASSERT(error != 0 || (td->td_pflags & TDP_EXECVMSPC) == 0,
301 *oldvmspace = p->p_vmspace;
306 post_execve(struct thread *td, int error, struct vmspace *oldvmspace)
310 KASSERT(td == curthread, ("non-current thread %p", td));
312 if ((p->p_flag & P_HADTHREADS) != 0) {
315 * If success, we upgrade to SINGLE_EXIT state to
316 * force other threads to suicide.
319 thread_single(p, SINGLE_EXIT);
321 thread_single_end(p, SINGLE_BOUNDARY);
324 if ((td->td_pflags & TDP_EXECVMSPC) != 0) {
325 KASSERT(p->p_vmspace != oldvmspace,
326 ("oldvmspace still used"));
327 vmspace_free(oldvmspace);
328 td->td_pflags &= ~TDP_EXECVMSPC;
333 * XXX: kern_execve has the astonishing property of not always returning to
334 * the caller. If sufficiently bad things happen during the call to
335 * do_execve(), it can end up calling exit1(); as a result, callers must
336 * avoid doing anything which they might need to undo (e.g., allocating
340 kern_execve(struct thread *td, struct image_args *args, struct mac *mac_p)
343 AUDIT_ARG_ARGV(args->begin_argv, args->argc,
344 args->begin_envv - args->begin_argv);
345 AUDIT_ARG_ENVV(args->begin_envv, args->envc,
346 args->endp - args->begin_envv);
347 return (do_execve(td, args, mac_p));
351 * In-kernel implementation of execve(). All arguments are assumed to be
352 * userspace pointers from the passed thread.
355 do_execve(td, args, mac_p)
357 struct image_args *args;
360 struct proc *p = td->td_proc;
362 struct ucred *newcred = NULL, *oldcred;
363 struct uidinfo *euip = NULL;
364 register_t *stack_base;
366 struct image_params image_params, *imgp;
368 int (*img_first)(struct image_params *);
369 struct pargs *oldargs = NULL, *newargs = NULL;
370 struct sigacts *oldsigacts, *newsigacts;
372 struct vnode *tracevp = NULL;
373 struct ucred *tracecred = NULL;
375 struct vnode *oldtextvp = NULL, *newtextvp;
377 int credential_changing;
380 struct label *interpvplabel = NULL;
384 struct pmckern_procexec pe;
386 static const char fexecv_proc_title[] = "(fexecv)";
388 imgp = &image_params;
391 * Lock the process and set the P_INEXEC flag to indicate that
392 * it should be left alone until we're done here. This is
393 * necessary to avoid race conditions - e.g. in ptrace() -
394 * that might allow a local user to illicitly obtain elevated
398 KASSERT((p->p_flag & P_INEXEC) == 0,
399 ("%s(): process already has P_INEXEC flag", __func__));
400 p->p_flag |= P_INEXEC;
404 * Initialize part of the common data
406 bzero(imgp, sizeof(*imgp));
412 error = mac_execve_enter(imgp, mac_p);
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_PROBE1(proc, kernel, , exec, args->fname);
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)) {
449 newtextvp = nd.ni_vp;
450 imgp->vp = newtextvp;
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), &newtextvp);
460 vn_lock(newtextvp, LK_EXCLUSIVE | LK_RETRY);
461 AUDIT_ARG_VNODE1(newtextvp);
462 imgp->vp = newtextvp;
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(newtextvp, &interpvplabel);
542 VOP_CLOSE(newtextvp, 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.
601 /* close files on exec */
605 * Malloc things before we need locks.
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 vn_lock(imgp->vp, LK_SHARED | LK_RETRY);
617 * For security and other reasons, signal handlers cannot
618 * be shared after an exec. The new process gets a copy of the old
619 * handlers. In execsigs(), the new process will have its signals
622 if (sigacts_shared(p->p_sigacts)) {
623 oldsigacts = p->p_sigacts;
624 newsigacts = sigacts_alloc();
625 sigacts_copy(newsigacts, oldsigacts);
628 newsigacts = NULL; /* satisfy gcc */
633 p->p_sigacts = newsigacts;
634 oldcred = p->p_ucred;
638 /* reset caught signals */
641 /* name this process - nameiexec(p, ndp) */
642 bzero(p->p_comm, sizeof(p->p_comm));
644 bcopy(nd.ni_cnd.cn_nameptr, p->p_comm,
645 min(nd.ni_cnd.cn_namelen, MAXCOMLEN));
646 else if (vn_commname(newtextvp, p->p_comm, sizeof(p->p_comm)) != 0)
647 bcopy(fexecv_proc_title, p->p_comm, sizeof(fexecv_proc_title));
648 bcopy(p->p_comm, td->td_name, sizeof(td->td_name));
650 sched_clear_tdname(td);
654 * mark as execed, wakeup the process that vforked (if any) and tell
655 * it that it now has its own resources back
658 if ((p->p_flag2 & P2_NOTRACE_EXEC) == 0)
659 p->p_flag2 &= ~P2_NOTRACE;
660 if (p->p_flag & P_PPWAIT) {
661 p->p_flag &= ~(P_PPWAIT | P_PPTRACE);
662 cv_broadcast(&p->p_pwait);
666 * Implement image setuid/setgid.
668 * Don't honor setuid/setgid if the filesystem prohibits it or if
669 * the process is being traced.
671 * We disable setuid/setgid/etc in capability mode on the basis
672 * that most setugid applications are not written with that
673 * environment in mind, and will therefore almost certainly operate
674 * incorrectly. In principle there's no reason that setugid
675 * applications might not be useful in capability mode, so we may want
676 * to reconsider this conservative design choice in the future.
678 * XXXMAC: For the time being, use NOSUID to also prohibit
679 * transitions on the file system.
681 credential_changing = 0;
682 credential_changing |= (attr.va_mode & S_ISUID) && oldcred->cr_uid !=
684 credential_changing |= (attr.va_mode & S_ISGID) && oldcred->cr_gid !=
687 will_transition = mac_vnode_execve_will_transition(oldcred, imgp->vp,
688 interpvplabel, imgp);
689 credential_changing |= will_transition;
692 if (credential_changing &&
693 #ifdef CAPABILITY_MODE
694 ((oldcred->cr_flags & CRED_FLAG_CAPMODE) == 0) &&
696 (imgp->vp->v_mount->mnt_flag & MNT_NOSUID) == 0 &&
697 (p->p_flag & P_TRACED) == 0) {
699 * Turn off syscall tracing for set-id programs, except for
700 * root. Record any set-id flags first to make sure that
701 * we do not regain any tracing during a possible block.
706 if (p->p_tracecred != NULL &&
707 priv_check_cred(p->p_tracecred, PRIV_DEBUG_DIFFCRED, 0))
708 ktrprocexec(p, &tracecred, &tracevp);
711 * Close any file descriptors 0..2 that reference procfs,
712 * then make sure file descriptors 0..2 are in use.
714 * setugidsafety() may call closef() and then pfind()
715 * which may grab the process lock.
716 * fdcheckstd() may call falloc() which may block to
717 * allocate memory, so temporarily drop the process lock.
720 VOP_UNLOCK(imgp->vp, 0);
722 error = fdcheckstd(td);
725 newcred = crdup(oldcred);
726 euip = uifind(attr.va_uid);
727 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 proc_set_cred(p, newcred);
753 if (oldcred->cr_uid == oldcred->cr_ruid &&
754 oldcred->cr_gid == oldcred->cr_rgid)
755 p->p_flag &= ~P_SUGID;
757 * Implement correct POSIX saved-id behavior.
759 * XXX: It's not clear that the existing behavior is
760 * POSIX-compliant. A number of sources indicate that the
761 * saved uid/gid should only be updated if the new ruid is
762 * not equal to the old ruid, or the new euid is not equal
763 * to the old euid and the new euid is not equal to the old
764 * ruid. The FreeBSD code always updates the saved uid/gid.
765 * Also, this code uses the new (replaced) euid and egid as
766 * the source, which may or may not be the right ones to use.
768 if (oldcred->cr_svuid != oldcred->cr_uid ||
769 oldcred->cr_svgid != oldcred->cr_gid) {
771 VOP_UNLOCK(imgp->vp, 0);
772 newcred = crdup(oldcred);
773 vn_lock(imgp->vp, LK_SHARED | LK_RETRY);
775 change_svuid(newcred, newcred->cr_uid);
776 change_svgid(newcred, newcred->cr_gid);
777 proc_set_cred(p, newcred);
782 * Store the vp for use in procfs. This vnode was referenced by namei
785 oldtextvp = p->p_textvp;
786 p->p_textvp = newtextvp;
790 * Tell the DTrace fasttrap provider about the exec if it
791 * has declared an interest.
793 if (dtrace_fasttrap_exec)
794 dtrace_fasttrap_exec(p);
798 * Notify others that we exec'd, and clear the P_INEXEC flag
799 * as we're now a bona fide freshly-execed process.
801 KNOTE_LOCKED(&p->p_klist, NOTE_EXEC);
802 p->p_flag &= ~P_INEXEC;
804 /* clear "fork but no exec" flag, as we _are_ execing */
805 p->p_acflag &= ~AFORK;
808 * Free any previous argument cache and replace it with
809 * the new argument cache, if any.
817 * Check if system-wide sampling is in effect or if the
818 * current process is using PMCs. If so, do exec() time
819 * processing. This processing needs to happen AFTER the
820 * P_INEXEC flag is cleared.
822 * The proc lock needs to be released before taking the PMC
825 if (PMC_SYSTEM_SAMPLING_ACTIVE() || PMC_PROC_IS_USING_PMCS(p)) {
827 VOP_UNLOCK(imgp->vp, 0);
828 pe.pm_credentialschanged = credential_changing;
829 pe.pm_entryaddr = imgp->entry_addr;
831 PMC_CALL_HOOK_X(td, PMC_FN_PROCESS_EXEC, (void *) &pe);
832 vn_lock(imgp->vp, LK_SHARED | LK_RETRY);
835 #else /* !HWPMC_HOOKS */
839 /* Set values passed into the program in registers. */
840 if (p->p_sysent->sv_setregs)
841 (*p->p_sysent->sv_setregs)(td, imgp,
842 (u_long)(uintptr_t)stack_base);
844 exec_setregs(td, imgp, (u_long)(uintptr_t)stack_base);
846 vfs_mark_atime(imgp->vp, td->td_ucred);
848 SDT_PROBE1(proc, kernel, , exec__success, args->fname);
850 VOP_UNLOCK(imgp->vp, 0);
853 * Free any resources malloc'd earlier that we didn't use.
861 * Handle deferred decrement of ref counts.
863 if (oldtextvp != NULL)
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 VOP_UNLOCK(imgp->vp, 0);
896 if (imgp->object != NULL)
897 vm_object_deallocate(imgp->object);
899 free(imgp->freepath, M_TEMP);
903 td->td_dbgflags |= TDB_EXEC;
907 * Stop the process here if its stop event mask has
908 * the S_EXEC bit set.
910 STOPEVENT(p, S_EXEC, 0);
915 /* we're done here, clear P_INEXEC */
917 p->p_flag &= ~P_INEXEC;
920 SDT_PROBE1(proc, kernel, , exec__failure, error);
924 mac_execve_exit(imgp);
925 mac_execve_interpreter_exit(interpvplabel);
927 exec_free_args(args);
929 if (error && imgp->vmspace_destroyed) {
930 /* sorry, no more process anymore. exit gracefully */
931 exit1(td, W_EXITCODE(0, SIGABRT));
944 exec_map_first_page(imgp)
945 struct image_params *imgp;
949 vm_page_t ma[VM_INITIAL_PAGEIN];
952 if (imgp->firstpage != NULL)
953 exec_unmap_first_page(imgp);
955 object = imgp->vp->v_object;
958 VM_OBJECT_WLOCK(object);
959 #if VM_NRESERVLEVEL > 0
960 if ((object->flags & OBJ_COLORED) == 0) {
961 object->flags |= OBJ_COLORED;
962 object->pg_color = 0;
965 ma[0] = vm_page_grab(object, 0, VM_ALLOC_NORMAL);
966 if (ma[0]->valid != VM_PAGE_BITS_ALL) {
967 initial_pagein = VM_INITIAL_PAGEIN;
968 if (initial_pagein > object->size)
969 initial_pagein = object->size;
970 for (i = 1; i < initial_pagein; i++) {
971 if ((ma[i] = vm_page_next(ma[i - 1])) != NULL) {
974 if (vm_page_tryxbusy(ma[i]))
977 ma[i] = vm_page_alloc(object, i,
978 VM_ALLOC_NORMAL | VM_ALLOC_IFNOTCACHED);
984 rv = vm_pager_get_pages(object, ma, initial_pagein, 0);
985 ma[0] = vm_page_lookup(object, 0);
986 if ((rv != VM_PAGER_OK) || (ma[0] == NULL)) {
990 vm_page_unlock(ma[0]);
992 VM_OBJECT_WUNLOCK(object);
996 vm_page_xunbusy(ma[0]);
999 vm_page_activate(ma[0]);
1000 vm_page_unlock(ma[0]);
1001 VM_OBJECT_WUNLOCK(object);
1003 imgp->firstpage = sf_buf_alloc(ma[0], 0);
1004 imgp->image_header = (char *)sf_buf_kva(imgp->firstpage);
1010 exec_unmap_first_page(imgp)
1011 struct image_params *imgp;
1015 if (imgp->firstpage != NULL) {
1016 m = sf_buf_page(imgp->firstpage);
1017 sf_buf_free(imgp->firstpage);
1018 imgp->firstpage = NULL;
1026 * Destroy old address space, and allocate a new stack
1027 * The new stack is only SGROWSIZ large because it is grown
1028 * automatically in trap.c.
1031 exec_new_vmspace(imgp, sv)
1032 struct image_params *imgp;
1033 struct sysentvec *sv;
1036 struct proc *p = imgp->proc;
1037 struct vmspace *vmspace = p->p_vmspace;
1039 struct rlimit rlim_stack;
1040 vm_offset_t sv_minuser, stack_addr;
1044 imgp->vmspace_destroyed = 1;
1047 /* May be called with Giant held */
1048 EVENTHANDLER_INVOKE(process_exec, p, imgp);
1051 * Blow away entire process VM, if address space not shared,
1052 * otherwise, create a new VM space so that other threads are
1055 map = &vmspace->vm_map;
1057 sv_minuser = sv->sv_minuser;
1059 sv_minuser = MAX(sv->sv_minuser, PAGE_SIZE);
1060 if (vmspace->vm_refcnt == 1 && vm_map_min(map) == sv_minuser &&
1061 vm_map_max(map) == sv->sv_maxuser) {
1063 pmap_remove_pages(vmspace_pmap(vmspace));
1064 vm_map_remove(map, vm_map_min(map), vm_map_max(map));
1066 error = vmspace_exec(p, sv_minuser, sv->sv_maxuser);
1069 vmspace = p->p_vmspace;
1070 map = &vmspace->vm_map;
1073 /* Map a shared page */
1074 obj = sv->sv_shared_page_obj;
1076 vm_object_reference(obj);
1077 error = vm_map_fixed(map, obj, 0,
1078 sv->sv_shared_page_base, sv->sv_shared_page_len,
1079 VM_PROT_READ | VM_PROT_EXECUTE,
1080 VM_PROT_READ | VM_PROT_EXECUTE,
1081 MAP_INHERIT_SHARE | MAP_ACC_NO_CHARGE);
1083 vm_object_deallocate(obj);
1088 /* Allocate a new stack */
1089 if (imgp->stack_sz != 0) {
1090 ssiz = trunc_page(imgp->stack_sz);
1092 lim_rlimit(p, RLIMIT_STACK, &rlim_stack);
1094 if (ssiz > rlim_stack.rlim_max)
1095 ssiz = rlim_stack.rlim_max;
1096 if (ssiz > rlim_stack.rlim_cur) {
1097 rlim_stack.rlim_cur = ssiz;
1098 kern_setrlimit(curthread, RLIMIT_STACK, &rlim_stack);
1100 } else if (sv->sv_maxssiz != NULL) {
1101 ssiz = *sv->sv_maxssiz;
1105 stack_addr = sv->sv_usrstack - ssiz;
1106 error = vm_map_stack(map, stack_addr, (vm_size_t)ssiz,
1107 obj != NULL && imgp->stack_prot != 0 ? imgp->stack_prot :
1109 VM_PROT_ALL, MAP_STACK_GROWS_DOWN);
1114 /* Allocate a new register stack */
1115 error = vm_map_stack(map, IA64_BACKINGSTORE, (vm_size_t)ssiz,
1116 sv->sv_stackprot, VM_PROT_ALL, MAP_STACK_GROWS_UP);
1121 /* vm_ssize and vm_maxsaddr are somewhat antiquated concepts in the
1122 * VM_STACK case, but they are still used to monitor the size of the
1123 * process stack so we can check the stack rlimit.
1125 vmspace->vm_ssize = sgrowsiz >> PAGE_SHIFT;
1126 vmspace->vm_maxsaddr = (char *)stack_addr;
1132 * Copy out argument and environment strings from the old process address
1133 * space into the temporary string buffer.
1136 exec_copyin_args(struct image_args *args, char *fname,
1137 enum uio_seg segflg, char **argv, char **envv)
1143 bzero(args, sizeof(*args));
1148 * Allocate demand-paged memory for the file name, argument, and
1149 * environment strings.
1151 error = exec_alloc_args(args);
1156 * Copy the file name.
1158 if (fname != NULL) {
1159 args->fname = args->buf;
1160 error = (segflg == UIO_SYSSPACE) ?
1161 copystr(fname, args->fname, PATH_MAX, &length) :
1162 copyinstr(fname, args->fname, PATH_MAX, &length);
1168 args->begin_argv = args->buf + length;
1169 args->endp = args->begin_argv;
1170 args->stringspace = ARG_MAX;
1173 * extract arguments first
1176 error = fueword(argv++, &argp);
1183 error = copyinstr((void *)(uintptr_t)argp, args->endp,
1184 args->stringspace, &length);
1186 if (error == ENAMETOOLONG)
1190 args->stringspace -= length;
1191 args->endp += length;
1195 args->begin_envv = args->endp;
1198 * extract environment strings
1202 error = fueword(envv++, &envp);
1209 error = copyinstr((void *)(uintptr_t)envp,
1210 args->endp, args->stringspace, &length);
1212 if (error == ENAMETOOLONG)
1216 args->stringspace -= length;
1217 args->endp += length;
1225 exec_free_args(args);
1230 * Allocate temporary demand-paged, zero-filled memory for the file name,
1231 * argument, and environment strings. Returns zero if the allocation succeeds
1232 * and ENOMEM otherwise.
1235 exec_alloc_args(struct image_args *args)
1238 args->buf = (char *)kmap_alloc_wait(exec_map, PATH_MAX + ARG_MAX);
1239 return (args->buf != NULL ? 0 : ENOMEM);
1243 exec_free_args(struct image_args *args)
1246 if (args->buf != NULL) {
1247 kmap_free_wakeup(exec_map, (vm_offset_t)args->buf,
1248 PATH_MAX + ARG_MAX);
1251 if (args->fname_buf != NULL) {
1252 free(args->fname_buf, M_TEMP);
1253 args->fname_buf = NULL;
1258 * Copy strings out to the new process address space, constructing new arg
1259 * and env vector tables. Return a pointer to the base so that it can be used
1260 * as the initial stack pointer.
1263 exec_copyout_strings(imgp)
1264 struct image_params *imgp;
1270 register_t *stack_base;
1271 struct ps_strings *arginfo;
1273 size_t execpath_len;
1274 int szsigcode, szps;
1275 char canary[sizeof(long) * 8];
1277 szps = sizeof(pagesizes[0]) * MAXPAGESIZES;
1279 * Calculate string base and vector table pointers.
1280 * Also deal with signal trampoline code for this exec type.
1282 if (imgp->execpath != NULL && imgp->auxargs != NULL)
1283 execpath_len = strlen(imgp->execpath) + 1;
1288 arginfo = (struct ps_strings *)p->p_sysent->sv_psstrings;
1289 if (p->p_sysent->sv_sigcode_base == 0) {
1290 if (p->p_sysent->sv_szsigcode != NULL)
1291 szsigcode = *(p->p_sysent->sv_szsigcode);
1293 destp = (uintptr_t)arginfo;
1298 if (szsigcode != 0) {
1300 destp = rounddown2(destp, sizeof(void *));
1301 copyout(p->p_sysent->sv_sigcode, (void *)destp, szsigcode);
1305 * Copy the image path for the rtld.
1307 if (execpath_len != 0) {
1308 destp -= execpath_len;
1309 imgp->execpathp = destp;
1310 copyout(imgp->execpath, (void *)destp, execpath_len);
1314 * Prepare the canary for SSP.
1316 arc4rand(canary, sizeof(canary), 0);
1317 destp -= sizeof(canary);
1318 imgp->canary = destp;
1319 copyout(canary, (void *)destp, sizeof(canary));
1320 imgp->canarylen = sizeof(canary);
1323 * Prepare the pagesizes array.
1326 destp = rounddown2(destp, sizeof(void *));
1327 imgp->pagesizes = destp;
1328 copyout(pagesizes, (void *)destp, szps);
1329 imgp->pagesizeslen = szps;
1331 destp -= ARG_MAX - imgp->args->stringspace;
1332 destp = rounddown2(destp, sizeof(void *));
1335 * If we have a valid auxargs ptr, prepare some room
1338 if (imgp->auxargs) {
1340 * 'AT_COUNT*2' is size for the ELF Auxargs data. This is for
1341 * lower compatibility.
1343 imgp->auxarg_size = (imgp->auxarg_size) ? imgp->auxarg_size :
1346 * The '+ 2' is for the null pointers at the end of each of
1347 * the arg and env vector sets,and imgp->auxarg_size is room
1348 * for argument of Runtime loader.
1350 vectp = (char **)(destp - (imgp->args->argc +
1351 imgp->args->envc + 2 + imgp->auxarg_size)
1355 * The '+ 2' is for the null pointers at the end of each of
1356 * the arg and env vector sets
1358 vectp = (char **)(destp - (imgp->args->argc + imgp->args->envc
1359 + 2) * sizeof(char *));
1363 * vectp also becomes our initial stack base
1365 stack_base = (register_t *)vectp;
1367 stringp = imgp->args->begin_argv;
1368 argc = imgp->args->argc;
1369 envc = imgp->args->envc;
1372 * Copy out strings - arguments and environment.
1374 copyout(stringp, (void *)destp, ARG_MAX - imgp->args->stringspace);
1377 * Fill in "ps_strings" struct for ps, w, etc.
1379 suword(&arginfo->ps_argvstr, (long)(intptr_t)vectp);
1380 suword32(&arginfo->ps_nargvstr, argc);
1383 * Fill in argument portion of vector table.
1385 for (; argc > 0; --argc) {
1386 suword(vectp++, (long)(intptr_t)destp);
1387 while (*stringp++ != 0)
1392 /* a null vector table pointer separates the argp's from the envp's */
1395 suword(&arginfo->ps_envstr, (long)(intptr_t)vectp);
1396 suword32(&arginfo->ps_nenvstr, envc);
1399 * Fill in environment portion of vector table.
1401 for (; envc > 0; --envc) {
1402 suword(vectp++, (long)(intptr_t)destp);
1403 while (*stringp++ != 0)
1408 /* end of vector table is a null pointer */
1411 return (stack_base);
1415 * Check permissions of file to execute.
1416 * Called with imgp->vp locked.
1417 * Return 0 for success or error code on failure.
1420 exec_check_permissions(imgp)
1421 struct image_params *imgp;
1423 struct vnode *vp = imgp->vp;
1424 struct vattr *attr = imgp->attr;
1426 int error, writecount;
1430 /* Get file attributes */
1431 error = VOP_GETATTR(vp, attr, td->td_ucred);
1436 error = mac_vnode_check_exec(td->td_ucred, imgp->vp, imgp);
1442 * 1) Check if file execution is disabled for the filesystem that
1443 * this file resides on.
1444 * 2) Ensure that at least one execute bit is on. Otherwise, a
1445 * privileged user will always succeed, and we don't want this
1446 * to happen unless the file really is executable.
1447 * 3) Ensure that the file is a regular file.
1449 if ((vp->v_mount->mnt_flag & MNT_NOEXEC) ||
1450 (attr->va_mode & (S_IXUSR | S_IXGRP | S_IXOTH)) == 0 ||
1451 (attr->va_type != VREG))
1455 * Zero length files can't be exec'd
1457 if (attr->va_size == 0)
1461 * Check for execute permission to file based on current credentials.
1463 error = VOP_ACCESS(vp, VEXEC, td->td_ucred, td);
1468 * Check number of open-for-writes on the file and deny execution
1471 error = VOP_GET_WRITECOUNT(vp, &writecount);
1474 if (writecount != 0)
1478 * Call filesystem specific open routine (which does nothing in the
1481 error = VOP_OPEN(vp, FREAD, td->td_ucred, td, NULL);
1488 * Exec handler registration
1491 exec_register(execsw_arg)
1492 const struct execsw *execsw_arg;
1494 const struct execsw **es, **xs, **newexecsw;
1495 int count = 2; /* New slot and trailing NULL */
1498 for (es = execsw; *es; es++)
1500 newexecsw = malloc(count * sizeof(*es), M_TEMP, M_WAITOK);
1501 if (newexecsw == NULL)
1505 for (es = execsw; *es; es++)
1510 free(execsw, M_TEMP);
1516 exec_unregister(execsw_arg)
1517 const struct execsw *execsw_arg;
1519 const struct execsw **es, **xs, **newexecsw;
1523 panic("unregister with no handlers left?\n");
1525 for (es = execsw; *es; es++) {
1526 if (*es == execsw_arg)
1531 for (es = execsw; *es; es++)
1532 if (*es != execsw_arg)
1534 newexecsw = malloc(count * sizeof(*es), M_TEMP, M_WAITOK);
1535 if (newexecsw == NULL)
1538 for (es = execsw; *es; es++)
1539 if (*es != execsw_arg)
1543 free(execsw, M_TEMP);