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/sched.h>
62 #include <sys/sf_buf.h>
63 #include <sys/syscallsubr.h>
64 #include <sys/sysent.h>
66 #include <sys/sysctl.h>
67 #include <sys/vnode.h>
70 #include <sys/ktrace.h>
74 #include <vm/vm_param.h>
76 #include <vm/vm_page.h>
77 #include <vm/vm_map.h>
78 #include <vm/vm_kern.h>
79 #include <vm/vm_extern.h>
80 #include <vm/vm_object.h>
81 #include <vm/vm_pager.h>
84 #include <sys/pmckern.h>
87 #include <machine/reg.h>
89 #include <security/audit/audit.h>
90 #include <security/mac/mac_framework.h>
93 #include <sys/dtrace_bsd.h>
94 dtrace_execexit_func_t dtrace_fasttrap_exec;
97 SDT_PROVIDER_DECLARE(proc);
98 SDT_PROBE_DEFINE(proc, kernel, , exec, exec);
99 SDT_PROBE_ARGTYPE(proc, kernel, , exec, 0, "char *");
100 SDT_PROBE_DEFINE(proc, kernel, , exec_failure, exec-failure);
101 SDT_PROBE_ARGTYPE(proc, kernel, , exec_failure, 0, "int");
102 SDT_PROBE_DEFINE(proc, kernel, , exec_success, exec-success);
103 SDT_PROBE_ARGTYPE(proc, kernel, , exec_success, 0, "char *");
105 MALLOC_DEFINE(M_PARGS, "proc-args", "Process arguments");
107 static int sysctl_kern_ps_strings(SYSCTL_HANDLER_ARGS);
108 static int sysctl_kern_usrstack(SYSCTL_HANDLER_ARGS);
109 static int sysctl_kern_stackprot(SYSCTL_HANDLER_ARGS);
110 static int do_execve(struct thread *td, struct image_args *args,
113 /* XXX This should be vm_size_t. */
114 SYSCTL_PROC(_kern, KERN_PS_STRINGS, ps_strings, CTLTYPE_ULONG|CTLFLAG_RD,
115 NULL, 0, sysctl_kern_ps_strings, "LU", "");
117 /* XXX This should be vm_size_t. */
118 SYSCTL_PROC(_kern, KERN_USRSTACK, usrstack, CTLTYPE_ULONG|CTLFLAG_RD|
119 CTLFLAG_CAPRD, NULL, 0, sysctl_kern_usrstack, "LU", "");
121 SYSCTL_PROC(_kern, OID_AUTO, stackprot, CTLTYPE_INT|CTLFLAG_RD,
122 NULL, 0, sysctl_kern_stackprot, "I", "");
124 u_long ps_arg_cache_limit = PAGE_SIZE / 16;
125 SYSCTL_ULONG(_kern, OID_AUTO, ps_arg_cache_limit, CTLFLAG_RW,
126 &ps_arg_cache_limit, 0, "");
128 static int map_at_zero = 0;
129 TUNABLE_INT("security.bsd.map_at_zero", &map_at_zero);
130 SYSCTL_INT(_security_bsd, OID_AUTO, map_at_zero, CTLFLAG_RW, &map_at_zero, 0,
131 "Permit processes to map an object at virtual address 0.");
134 sysctl_kern_ps_strings(SYSCTL_HANDLER_ARGS)
141 if (req->flags & SCTL_MASK32) {
143 val = (unsigned int)p->p_sysent->sv_psstrings;
144 error = SYSCTL_OUT(req, &val, sizeof(val));
147 error = SYSCTL_OUT(req, &p->p_sysent->sv_psstrings,
148 sizeof(p->p_sysent->sv_psstrings));
153 sysctl_kern_usrstack(SYSCTL_HANDLER_ARGS)
160 if (req->flags & SCTL_MASK32) {
162 val = (unsigned int)p->p_sysent->sv_usrstack;
163 error = SYSCTL_OUT(req, &val, sizeof(val));
166 error = SYSCTL_OUT(req, &p->p_sysent->sv_usrstack,
167 sizeof(p->p_sysent->sv_usrstack));
172 sysctl_kern_stackprot(SYSCTL_HANDLER_ARGS)
177 return (SYSCTL_OUT(req, &p->p_sysent->sv_stackprot,
178 sizeof(p->p_sysent->sv_stackprot)));
182 * Each of the items is a pointer to a `const struct execsw', hence the
183 * double pointer here.
185 static const struct execsw **execsw;
187 #ifndef _SYS_SYSPROTO_H_
198 struct execve_args /* {
205 struct image_args args;
207 error = exec_copyin_args(&args, uap->fname, UIO_USERSPACE,
208 uap->argv, uap->envv);
210 error = kern_execve(td, &args, NULL);
214 #ifndef _SYS_SYSPROTO_H_
215 struct fexecve_args {
222 sys_fexecve(struct thread *td, struct fexecve_args *uap)
225 struct image_args args;
227 error = exec_copyin_args(&args, NULL, UIO_SYSSPACE,
228 uap->argv, uap->envv);
231 error = kern_execve(td, &args, NULL);
236 #ifndef _SYS_SYSPROTO_H_
237 struct __mac_execve_args {
246 sys___mac_execve(td, uap)
248 struct __mac_execve_args /* {
257 struct image_args args;
259 error = exec_copyin_args(&args, uap->fname, UIO_USERSPACE,
260 uap->argv, uap->envv);
262 error = kern_execve(td, &args, uap->mac_p);
270 * XXX: kern_execve has the astonishing property of not always returning to
271 * the caller. If sufficiently bad things happen during the call to
272 * do_execve(), it can end up calling exit1(); as a result, callers must
273 * avoid doing anything which they might need to undo (e.g., allocating
277 kern_execve(td, args, mac_p)
279 struct image_args *args;
282 struct proc *p = td->td_proc;
285 AUDIT_ARG_ARGV(args->begin_argv, args->argc,
286 args->begin_envv - args->begin_argv);
287 AUDIT_ARG_ENVV(args->begin_envv, args->envc,
288 args->endp - args->begin_envv);
289 if (p->p_flag & P_HADTHREADS) {
291 if (thread_single(SINGLE_BOUNDARY)) {
293 exec_free_args(args);
294 return (ERESTART); /* Try again later. */
299 error = do_execve(td, args, mac_p);
301 if (p->p_flag & P_HADTHREADS) {
304 * If success, we upgrade to SINGLE_EXIT state to
305 * force other threads to suicide.
308 thread_single(SINGLE_EXIT);
318 * In-kernel implementation of execve(). All arguments are assumed to be
319 * userspace pointers from the passed thread.
322 do_execve(td, args, mac_p)
324 struct image_args *args;
327 struct proc *p = td->td_proc;
329 struct ucred *newcred = NULL, *oldcred;
330 struct uidinfo *euip;
331 register_t *stack_base;
333 struct image_params image_params, *imgp;
335 int (*img_first)(struct image_params *);
336 struct pargs *oldargs = NULL, *newargs = NULL;
337 struct sigacts *oldsigacts, *newsigacts;
339 struct vnode *tracevp = NULL;
340 struct ucred *tracecred = NULL;
342 struct vnode *textvp = NULL, *binvp = NULL;
343 int credential_changing;
346 struct label *interpvplabel = NULL;
350 struct pmckern_procexec pe;
352 static const char fexecv_proc_title[] = "(fexecv)";
354 imgp = &image_params;
357 * Lock the process and set the P_INEXEC flag to indicate that
358 * it should be left alone until we're done here. This is
359 * necessary to avoid race conditions - e.g. in ptrace() -
360 * that might allow a local user to illicitly obtain elevated
364 KASSERT((p->p_flag & P_INEXEC) == 0,
365 ("%s(): process already has P_INEXEC flag", __func__));
366 p->p_flag |= P_INEXEC;
370 * Initialize part of the common data
373 imgp->execlabel = NULL;
375 imgp->entry_addr = 0;
376 imgp->reloc_base = 0;
377 imgp->vmspace_destroyed = 0;
378 imgp->interpreted = 0;
380 imgp->interpreter_name = NULL;
381 imgp->auxargs = NULL;
384 imgp->firstpage = NULL;
385 imgp->ps_strings = 0;
386 imgp->auxarg_size = 0;
388 imgp->execpath = imgp->freepath = NULL;
393 imgp->pagesizeslen = 0;
394 imgp->stack_prot = 0;
397 error = mac_execve_enter(imgp, mac_p);
402 imgp->image_header = NULL;
405 * Translate the file name. namei() returns a vnode pointer
406 * in ni_vp amoung other things.
408 * XXXAUDIT: It would be desirable to also audit the name of the
409 * interpreter if this is an interpreted binary.
411 if (args->fname != NULL) {
412 NDINIT(&nd, LOOKUP, ISOPEN | LOCKLEAF | FOLLOW | SAVENAME
413 | AUDITVNODE1, UIO_SYSSPACE, args->fname, td);
416 SDT_PROBE(proc, kernel, , exec, args->fname, 0, 0, 0, 0 );
419 if (args->fname != NULL) {
420 #ifdef CAPABILITY_MODE
422 * While capability mode can't reach this point via direct
423 * path arguments to execve(), we also don't allow
424 * interpreters to be used in capability mode (for now).
425 * Catch indirect lookups and return a permissions error.
427 if (IN_CAPABILITY_MODE(td)) {
439 AUDIT_ARG_FD(args->fd);
441 * Some might argue that CAP_READ and/or CAP_MMAP should also
442 * be required here; such arguments will be entertained.
444 * Descriptors opened only with O_EXEC or O_RDONLY are allowed.
446 error = fgetvp_exec(td, args->fd, CAP_FEXECVE, &binvp);
449 vn_lock(binvp, LK_EXCLUSIVE | LK_RETRY);
450 AUDIT_ARG_VNODE1(binvp);
455 * Check file permissions (also 'opens' file)
457 error = exec_check_permissions(imgp);
459 goto exec_fail_dealloc;
461 imgp->object = imgp->vp->v_object;
462 if (imgp->object != NULL)
463 vm_object_reference(imgp->object);
466 * Set VV_TEXT now so no one can write to the executable while we're
469 * Remember if this was set before and unset it in case this is not
470 * actually an executable image.
472 textset = VOP_IS_TEXT(imgp->vp);
473 VOP_SET_TEXT(imgp->vp);
475 error = exec_map_first_page(imgp);
477 goto exec_fail_dealloc;
479 imgp->proc->p_osrel = 0;
481 * If the current process has a special image activator it
482 * wants to try first, call it. For example, emulating shell
483 * scripts differently.
486 if ((img_first = imgp->proc->p_sysent->sv_imgact_try) != NULL)
487 error = img_first(imgp);
490 * Loop through the list of image activators, calling each one.
491 * An activator returns -1 if there is no match, 0 on success,
492 * and an error otherwise.
494 for (i = 0; error == -1 && execsw[i]; ++i) {
495 if (execsw[i]->ex_imgact == NULL ||
496 execsw[i]->ex_imgact == img_first) {
499 error = (*execsw[i]->ex_imgact)(imgp);
505 VOP_UNSET_TEXT(imgp->vp);
508 goto exec_fail_dealloc;
512 * Special interpreter operation, cleanup and loop up to try to
513 * activate the interpreter.
515 if (imgp->interpreted) {
516 exec_unmap_first_page(imgp);
518 * VV_TEXT needs to be unset for scripts. There is a short
519 * period before we determine that something is a script where
520 * VV_TEXT will be set. The vnode lock is held over this
521 * entire period so nothing should illegitimately be blocked.
523 VOP_UNSET_TEXT(imgp->vp);
524 /* free name buffer and old vnode */
525 if (args->fname != NULL)
526 NDFREE(&nd, NDF_ONLY_PNBUF);
528 mac_execve_interpreter_enter(binvp, &interpvplabel);
531 VOP_CLOSE(binvp, FREAD, td->td_ucred, td);
535 vm_object_deallocate(imgp->object);
537 /* set new name to that of the interpreter */
538 NDINIT(&nd, LOOKUP, LOCKLEAF | FOLLOW | SAVENAME,
539 UIO_SYSSPACE, imgp->interpreter_name, td);
540 args->fname = imgp->interpreter_name;
545 * NB: We unlock the vnode here because it is believed that none
546 * of the sv_copyout_strings/sv_fixup operations require the vnode.
548 VOP_UNLOCK(imgp->vp, 0);
551 * Do the best to calculate the full path to the image file.
553 if (imgp->auxargs != NULL &&
554 ((args->fname != NULL && args->fname[0] == '/') ||
555 vn_fullpath(td, imgp->vp, &imgp->execpath, &imgp->freepath) != 0))
556 imgp->execpath = args->fname;
559 * Copy out strings (args and env) and initialize stack base
561 if (p->p_sysent->sv_copyout_strings)
562 stack_base = (*p->p_sysent->sv_copyout_strings)(imgp);
564 stack_base = exec_copyout_strings(imgp);
567 * If custom stack fixup routine present for this process
568 * let it do the stack setup.
569 * Else stuff argument count as first item on stack
571 if (p->p_sysent->sv_fixup != NULL)
572 (*p->p_sysent->sv_fixup)(&stack_base, imgp);
574 suword(--stack_base, imgp->args->argc);
577 * For security and other reasons, the file descriptor table cannot
578 * be shared after an exec.
583 * Malloc things before we need locks.
586 euip = uifind(attr.va_uid);
587 i = imgp->args->begin_envv - imgp->args->begin_argv;
588 /* Cache arguments if they fit inside our allowance */
589 if (ps_arg_cache_limit >= i + sizeof(struct pargs)) {
590 newargs = pargs_alloc(i);
591 bcopy(imgp->args->begin_argv, newargs->ar_args, i);
594 /* close files on exec */
596 vn_lock(imgp->vp, LK_SHARED | LK_RETRY);
598 /* Get a reference to the vnode prior to locking the proc */
602 * For security and other reasons, signal handlers cannot
603 * be shared after an exec. The new process gets a copy of the old
604 * handlers. In execsigs(), the new process will have its signals
608 oldcred = crcopysafe(p, newcred);
609 if (sigacts_shared(p->p_sigacts)) {
610 oldsigacts = p->p_sigacts;
612 newsigacts = sigacts_alloc();
613 sigacts_copy(newsigacts, oldsigacts);
615 p->p_sigacts = newsigacts;
622 /* reset caught signals */
625 /* name this process - nameiexec(p, ndp) */
626 bzero(p->p_comm, sizeof(p->p_comm));
628 bcopy(nd.ni_cnd.cn_nameptr, p->p_comm,
629 min(nd.ni_cnd.cn_namelen, MAXCOMLEN));
630 else if (vn_commname(binvp, p->p_comm, sizeof(p->p_comm)) != 0)
631 bcopy(fexecv_proc_title, p->p_comm, sizeof(fexecv_proc_title));
632 bcopy(p->p_comm, td->td_name, sizeof(td->td_name));
634 sched_clear_tdname(td);
638 * mark as execed, wakeup the process that vforked (if any) and tell
639 * it that it now has its own resources back
642 if (p->p_pptr && (p->p_flag & P_PPWAIT)) {
643 p->p_flag &= ~(P_PPWAIT | P_PPTRACE);
644 cv_broadcast(&p->p_pwait);
648 * Implement image setuid/setgid.
650 * Don't honor setuid/setgid if the filesystem prohibits it or if
651 * the process is being traced.
653 * We disable setuid/setgid/etc in compatibility mode on the basis
654 * that most setugid applications are not written with that
655 * environment in mind, and will therefore almost certainly operate
656 * incorrectly. In principle there's no reason that setugid
657 * applications might not be useful in capability mode, so we may want
658 * to reconsider this conservative design choice in the future.
660 * XXXMAC: For the time being, use NOSUID to also prohibit
661 * transitions on the file system.
663 credential_changing = 0;
664 credential_changing |= (attr.va_mode & S_ISUID) && oldcred->cr_uid !=
666 credential_changing |= (attr.va_mode & S_ISGID) && oldcred->cr_gid !=
669 will_transition = mac_vnode_execve_will_transition(oldcred, imgp->vp,
670 interpvplabel, imgp);
671 credential_changing |= will_transition;
674 if (credential_changing &&
675 #ifdef CAPABILITY_MODE
676 ((oldcred->cr_flags & CRED_FLAG_CAPMODE) == 0) &&
678 (imgp->vp->v_mount->mnt_flag & MNT_NOSUID) == 0 &&
679 (p->p_flag & P_TRACED) == 0) {
681 * Turn off syscall tracing for set-id programs, except for
682 * root. Record any set-id flags first to make sure that
683 * we do not regain any tracing during a possible block.
688 if (p->p_tracecred != NULL &&
689 priv_check_cred(p->p_tracecred, PRIV_DEBUG_DIFFCRED, 0))
690 ktrprocexec(p, &tracecred, &tracevp);
693 * Close any file descriptors 0..2 that reference procfs,
694 * then make sure file descriptors 0..2 are in use.
696 * setugidsafety() may call closef() and then pfind()
697 * which may grab the process lock.
698 * fdcheckstd() may call falloc() which may block to
699 * allocate memory, so temporarily drop the process lock.
702 VOP_UNLOCK(imgp->vp, 0);
704 error = fdcheckstd(td);
705 vn_lock(imgp->vp, LK_SHARED | LK_RETRY);
710 * Set the new credentials.
712 if (attr.va_mode & S_ISUID)
713 change_euid(newcred, euip);
714 if (attr.va_mode & S_ISGID)
715 change_egid(newcred, attr.va_gid);
717 if (will_transition) {
718 mac_vnode_execve_transition(oldcred, newcred, imgp->vp,
719 interpvplabel, imgp);
723 * Implement correct POSIX saved-id behavior.
725 * XXXMAC: Note that the current logic will save the
726 * uid and gid if a MAC domain transition occurs, even
727 * though maybe it shouldn't.
729 change_svuid(newcred, newcred->cr_uid);
730 change_svgid(newcred, newcred->cr_gid);
731 p->p_ucred = newcred;
734 if (oldcred->cr_uid == oldcred->cr_ruid &&
735 oldcred->cr_gid == oldcred->cr_rgid)
736 p->p_flag &= ~P_SUGID;
738 * Implement correct POSIX saved-id behavior.
740 * XXX: It's not clear that the existing behavior is
741 * POSIX-compliant. A number of sources indicate that the
742 * saved uid/gid should only be updated if the new ruid is
743 * not equal to the old ruid, or the new euid is not equal
744 * to the old euid and the new euid is not equal to the old
745 * ruid. The FreeBSD code always updates the saved uid/gid.
746 * Also, this code uses the new (replaced) euid and egid as
747 * the source, which may or may not be the right ones to use.
749 if (oldcred->cr_svuid != oldcred->cr_uid ||
750 oldcred->cr_svgid != oldcred->cr_gid) {
751 change_svuid(newcred, newcred->cr_uid);
752 change_svgid(newcred, newcred->cr_gid);
753 p->p_ucred = newcred;
759 * Store the vp for use in procfs. This vnode was referenced prior
760 * to locking the proc lock.
762 textvp = p->p_textvp;
767 * Tell the DTrace fasttrap provider about the exec if it
768 * has declared an interest.
770 if (dtrace_fasttrap_exec)
771 dtrace_fasttrap_exec(p);
775 * Notify others that we exec'd, and clear the P_INEXEC flag
776 * as we're now a bona fide freshly-execed process.
778 KNOTE_LOCKED(&p->p_klist, NOTE_EXEC);
779 p->p_flag &= ~P_INEXEC;
781 /* clear "fork but no exec" flag, as we _are_ execing */
782 p->p_acflag &= ~AFORK;
785 * Free any previous argument cache and replace it with
786 * the new argument cache, if any.
794 * Check if system-wide sampling is in effect or if the
795 * current process is using PMCs. If so, do exec() time
796 * processing. This processing needs to happen AFTER the
797 * P_INEXEC flag is cleared.
799 * The proc lock needs to be released before taking the PMC
802 if (PMC_SYSTEM_SAMPLING_ACTIVE() || PMC_PROC_IS_USING_PMCS(p)) {
804 VOP_UNLOCK(imgp->vp, 0);
805 pe.pm_credentialschanged = credential_changing;
806 pe.pm_entryaddr = imgp->entry_addr;
808 PMC_CALL_HOOK_X(td, PMC_FN_PROCESS_EXEC, (void *) &pe);
809 vn_lock(imgp->vp, LK_SHARED | LK_RETRY);
812 #else /* !HWPMC_HOOKS */
816 /* Set values passed into the program in registers. */
817 if (p->p_sysent->sv_setregs)
818 (*p->p_sysent->sv_setregs)(td, imgp,
819 (u_long)(uintptr_t)stack_base);
821 exec_setregs(td, imgp, (u_long)(uintptr_t)stack_base);
823 vfs_mark_atime(imgp->vp, td->td_ucred);
825 SDT_PROBE(proc, kernel, , exec_success, args->fname, 0, 0, 0, 0);
829 * Free any resources malloc'd earlier that we didn't use.
836 VOP_UNLOCK(imgp->vp, 0);
839 * Handle deferred decrement of ref counts.
843 if (binvp && error != 0)
848 if (tracecred != NULL)
851 vn_lock(imgp->vp, LK_SHARED | LK_RETRY);
854 if (oldsigacts != NULL)
855 sigacts_free(oldsigacts);
860 * free various allocated resources
862 if (imgp->firstpage != NULL)
863 exec_unmap_first_page(imgp);
865 if (imgp->vp != NULL) {
867 NDFREE(&nd, NDF_ONLY_PNBUF);
869 VOP_CLOSE(imgp->vp, FREAD, td->td_ucred, td);
873 if (imgp->object != NULL)
874 vm_object_deallocate(imgp->object);
876 free(imgp->freepath, M_TEMP);
880 td->td_dbgflags |= TDB_EXEC;
884 * Stop the process here if its stop event mask has
885 * the S_EXEC bit set.
887 STOPEVENT(p, S_EXEC, 0);
892 /* we're done here, clear P_INEXEC */
894 p->p_flag &= ~P_INEXEC;
897 SDT_PROBE(proc, kernel, , exec_failure, error, 0, 0, 0, 0);
901 mac_execve_exit(imgp);
902 mac_execve_interpreter_exit(interpvplabel);
904 exec_free_args(args);
906 if (error && imgp->vmspace_destroyed) {
907 /* sorry, no more process anymore. exit gracefully */
908 exit1(td, W_EXITCODE(0, SIGABRT));
921 exec_map_first_page(imgp)
922 struct image_params *imgp;
926 vm_page_t ma[VM_INITIAL_PAGEIN];
929 if (imgp->firstpage != NULL)
930 exec_unmap_first_page(imgp);
932 object = imgp->vp->v_object;
935 VM_OBJECT_LOCK(object);
936 #if VM_NRESERVLEVEL > 0
937 if ((object->flags & OBJ_COLORED) == 0) {
938 object->flags |= OBJ_COLORED;
939 object->pg_color = 0;
942 ma[0] = vm_page_grab(object, 0, VM_ALLOC_NORMAL | VM_ALLOC_RETRY);
943 if (ma[0]->valid != VM_PAGE_BITS_ALL) {
944 initial_pagein = VM_INITIAL_PAGEIN;
945 if (initial_pagein > object->size)
946 initial_pagein = object->size;
947 for (i = 1; i < initial_pagein; i++) {
948 if ((ma[i] = vm_page_next(ma[i - 1])) != NULL) {
951 if ((ma[i]->oflags & VPO_BUSY) || ma[i]->busy)
955 ma[i] = vm_page_alloc(object, i,
956 VM_ALLOC_NORMAL | VM_ALLOC_IFNOTCACHED);
962 rv = vm_pager_get_pages(object, ma, initial_pagein, 0);
963 ma[0] = vm_page_lookup(object, 0);
964 if ((rv != VM_PAGER_OK) || (ma[0] == NULL)) {
968 vm_page_unlock(ma[0]);
970 VM_OBJECT_UNLOCK(object);
976 vm_page_unlock(ma[0]);
977 vm_page_wakeup(ma[0]);
978 VM_OBJECT_UNLOCK(object);
980 imgp->firstpage = sf_buf_alloc(ma[0], 0);
981 imgp->image_header = (char *)sf_buf_kva(imgp->firstpage);
987 exec_unmap_first_page(imgp)
988 struct image_params *imgp;
992 if (imgp->firstpage != NULL) {
993 m = sf_buf_page(imgp->firstpage);
994 sf_buf_free(imgp->firstpage);
995 imgp->firstpage = NULL;
1003 * Destroy old address space, and allocate a new stack
1004 * The new stack is only SGROWSIZ large because it is grown
1005 * automatically in trap.c.
1008 exec_new_vmspace(imgp, sv)
1009 struct image_params *imgp;
1010 struct sysentvec *sv;
1013 struct proc *p = imgp->proc;
1014 struct vmspace *vmspace = p->p_vmspace;
1016 vm_offset_t sv_minuser, stack_addr;
1020 imgp->vmspace_destroyed = 1;
1023 /* May be called with Giant held */
1024 EVENTHANDLER_INVOKE(process_exec, p, imgp);
1027 * Blow away entire process VM, if address space not shared,
1028 * otherwise, create a new VM space so that other threads are
1031 map = &vmspace->vm_map;
1033 sv_minuser = sv->sv_minuser;
1035 sv_minuser = MAX(sv->sv_minuser, PAGE_SIZE);
1036 if (vmspace->vm_refcnt == 1 && vm_map_min(map) == sv_minuser &&
1037 vm_map_max(map) == sv->sv_maxuser) {
1039 pmap_remove_pages(vmspace_pmap(vmspace));
1040 vm_map_remove(map, vm_map_min(map), vm_map_max(map));
1042 error = vmspace_exec(p, sv_minuser, sv->sv_maxuser);
1045 vmspace = p->p_vmspace;
1046 map = &vmspace->vm_map;
1049 /* Map a shared page */
1050 obj = sv->sv_shared_page_obj;
1052 vm_object_reference(obj);
1053 error = vm_map_fixed(map, obj, 0,
1054 sv->sv_shared_page_base, sv->sv_shared_page_len,
1055 VM_PROT_READ | VM_PROT_EXECUTE, VM_PROT_ALL,
1056 MAP_COPY_ON_WRITE | MAP_ACC_NO_CHARGE);
1058 vm_object_deallocate(obj);
1063 /* Allocate a new stack */
1064 if (sv->sv_maxssiz != NULL)
1065 ssiz = *sv->sv_maxssiz;
1068 stack_addr = sv->sv_usrstack - ssiz;
1069 error = vm_map_stack(map, stack_addr, (vm_size_t)ssiz,
1070 obj != NULL && imgp->stack_prot != 0 ? imgp->stack_prot :
1072 VM_PROT_ALL, MAP_STACK_GROWS_DOWN);
1077 /* Allocate a new register stack */
1078 stack_addr = IA64_BACKINGSTORE;
1079 error = vm_map_stack(map, stack_addr, (vm_size_t)ssiz,
1080 sv->sv_stackprot, VM_PROT_ALL, MAP_STACK_GROWS_UP);
1085 /* vm_ssize and vm_maxsaddr are somewhat antiquated concepts in the
1086 * VM_STACK case, but they are still used to monitor the size of the
1087 * process stack so we can check the stack rlimit.
1089 vmspace->vm_ssize = sgrowsiz >> PAGE_SHIFT;
1090 vmspace->vm_maxsaddr = (char *)sv->sv_usrstack - ssiz;
1096 * Copy out argument and environment strings from the old process address
1097 * space into the temporary string buffer.
1100 exec_copyin_args(struct image_args *args, char *fname,
1101 enum uio_seg segflg, char **argv, char **envv)
1107 bzero(args, sizeof(*args));
1112 * Allocate demand-paged memory for the file name, argument, and
1113 * environment strings.
1115 error = exec_alloc_args(args);
1120 * Copy the file name.
1122 if (fname != NULL) {
1123 args->fname = args->buf;
1124 error = (segflg == UIO_SYSSPACE) ?
1125 copystr(fname, args->fname, PATH_MAX, &length) :
1126 copyinstr(fname, args->fname, PATH_MAX, &length);
1132 args->begin_argv = args->buf + length;
1133 args->endp = args->begin_argv;
1134 args->stringspace = ARG_MAX;
1137 * extract arguments first
1139 while ((argp = (caddr_t) (intptr_t) fuword(argv++))) {
1140 if (argp == (caddr_t) -1) {
1144 if ((error = copyinstr(argp, args->endp,
1145 args->stringspace, &length))) {
1146 if (error == ENAMETOOLONG)
1150 args->stringspace -= length;
1151 args->endp += length;
1155 args->begin_envv = args->endp;
1158 * extract environment strings
1161 while ((envp = (caddr_t)(intptr_t)fuword(envv++))) {
1162 if (envp == (caddr_t)-1) {
1166 if ((error = copyinstr(envp, args->endp,
1167 args->stringspace, &length))) {
1168 if (error == ENAMETOOLONG)
1172 args->stringspace -= length;
1173 args->endp += length;
1181 exec_free_args(args);
1186 * Allocate temporary demand-paged, zero-filled memory for the file name,
1187 * argument, and environment strings. Returns zero if the allocation succeeds
1188 * and ENOMEM otherwise.
1191 exec_alloc_args(struct image_args *args)
1194 args->buf = (char *)kmem_alloc_wait(exec_map, PATH_MAX + ARG_MAX);
1195 return (args->buf != NULL ? 0 : ENOMEM);
1199 exec_free_args(struct image_args *args)
1202 if (args->buf != NULL) {
1203 kmem_free_wakeup(exec_map, (vm_offset_t)args->buf,
1204 PATH_MAX + ARG_MAX);
1207 if (args->fname_buf != NULL) {
1208 free(args->fname_buf, M_TEMP);
1209 args->fname_buf = NULL;
1214 * Copy strings out to the new process address space, constructing new arg
1215 * and env vector tables. Return a pointer to the base so that it can be used
1216 * as the initial stack pointer.
1219 exec_copyout_strings(imgp)
1220 struct image_params *imgp;
1224 char *stringp, *destp;
1225 register_t *stack_base;
1226 struct ps_strings *arginfo;
1228 size_t execpath_len;
1229 int szsigcode, szps;
1230 char canary[sizeof(long) * 8];
1232 szps = sizeof(pagesizes[0]) * MAXPAGESIZES;
1234 * Calculate string base and vector table pointers.
1235 * Also deal with signal trampoline code for this exec type.
1237 if (imgp->execpath != NULL && imgp->auxargs != NULL)
1238 execpath_len = strlen(imgp->execpath) + 1;
1243 arginfo = (struct ps_strings *)p->p_sysent->sv_psstrings;
1244 if (p->p_sysent->sv_sigcode_base == 0) {
1245 if (p->p_sysent->sv_szsigcode != NULL)
1246 szsigcode = *(p->p_sysent->sv_szsigcode);
1248 destp = (caddr_t)arginfo - szsigcode - SPARE_USRSPACE -
1249 roundup(execpath_len, sizeof(char *)) -
1250 roundup(sizeof(canary), sizeof(char *)) -
1251 roundup(szps, sizeof(char *)) -
1252 roundup((ARG_MAX - imgp->args->stringspace), sizeof(char *));
1258 copyout(p->p_sysent->sv_sigcode, ((caddr_t)arginfo -
1259 szsigcode), szsigcode);
1262 * Copy the image path for the rtld.
1264 if (execpath_len != 0) {
1265 imgp->execpathp = (uintptr_t)arginfo - szsigcode - execpath_len;
1266 copyout(imgp->execpath, (void *)imgp->execpathp,
1271 * Prepare the canary for SSP.
1273 arc4rand(canary, sizeof(canary), 0);
1274 imgp->canary = (uintptr_t)arginfo - szsigcode - execpath_len -
1276 copyout(canary, (void *)imgp->canary, sizeof(canary));
1277 imgp->canarylen = sizeof(canary);
1280 * Prepare the pagesizes array.
1282 imgp->pagesizes = (uintptr_t)arginfo - szsigcode - execpath_len -
1283 roundup(sizeof(canary), sizeof(char *)) - szps;
1284 copyout(pagesizes, (void *)imgp->pagesizes, szps);
1285 imgp->pagesizeslen = szps;
1288 * If we have a valid auxargs ptr, prepare some room
1291 if (imgp->auxargs) {
1293 * 'AT_COUNT*2' is size for the ELF Auxargs data. This is for
1294 * lower compatibility.
1296 imgp->auxarg_size = (imgp->auxarg_size) ? imgp->auxarg_size :
1299 * The '+ 2' is for the null pointers at the end of each of
1300 * the arg and env vector sets,and imgp->auxarg_size is room
1301 * for argument of Runtime loader.
1303 vectp = (char **)(destp - (imgp->args->argc +
1304 imgp->args->envc + 2 + imgp->auxarg_size)
1308 * The '+ 2' is for the null pointers at the end of each of
1309 * the arg and env vector sets
1311 vectp = (char **)(destp - (imgp->args->argc + imgp->args->envc + 2) *
1316 * vectp also becomes our initial stack base
1318 stack_base = (register_t *)vectp;
1320 stringp = imgp->args->begin_argv;
1321 argc = imgp->args->argc;
1322 envc = imgp->args->envc;
1325 * Copy out strings - arguments and environment.
1327 copyout(stringp, destp, ARG_MAX - imgp->args->stringspace);
1330 * Fill in "ps_strings" struct for ps, w, etc.
1332 suword(&arginfo->ps_argvstr, (long)(intptr_t)vectp);
1333 suword32(&arginfo->ps_nargvstr, argc);
1336 * Fill in argument portion of vector table.
1338 for (; argc > 0; --argc) {
1339 suword(vectp++, (long)(intptr_t)destp);
1340 while (*stringp++ != 0)
1345 /* a null vector table pointer separates the argp's from the envp's */
1348 suword(&arginfo->ps_envstr, (long)(intptr_t)vectp);
1349 suword32(&arginfo->ps_nenvstr, envc);
1352 * Fill in environment portion of vector table.
1354 for (; envc > 0; --envc) {
1355 suword(vectp++, (long)(intptr_t)destp);
1356 while (*stringp++ != 0)
1361 /* end of vector table is a null pointer */
1364 return (stack_base);
1368 * Check permissions of file to execute.
1369 * Called with imgp->vp locked.
1370 * Return 0 for success or error code on failure.
1373 exec_check_permissions(imgp)
1374 struct image_params *imgp;
1376 struct vnode *vp = imgp->vp;
1377 struct vattr *attr = imgp->attr;
1379 int error, writecount;
1383 /* Get file attributes */
1384 error = VOP_GETATTR(vp, attr, td->td_ucred);
1389 error = mac_vnode_check_exec(td->td_ucred, imgp->vp, imgp);
1395 * 1) Check if file execution is disabled for the filesystem that
1396 * this file resides on.
1397 * 2) Ensure that at least one execute bit is on. Otherwise, a
1398 * privileged user will always succeed, and we don't want this
1399 * to happen unless the file really is executable.
1400 * 3) Ensure that the file is a regular file.
1402 if ((vp->v_mount->mnt_flag & MNT_NOEXEC) ||
1403 (attr->va_mode & (S_IXUSR | S_IXGRP | S_IXOTH)) == 0 ||
1404 (attr->va_type != VREG))
1408 * Zero length files can't be exec'd
1410 if (attr->va_size == 0)
1414 * Check for execute permission to file based on current credentials.
1416 error = VOP_ACCESS(vp, VEXEC, td->td_ucred, td);
1421 * Check number of open-for-writes on the file and deny execution
1424 error = VOP_GET_WRITECOUNT(vp, &writecount);
1427 if (writecount != 0)
1431 * Call filesystem specific open routine (which does nothing in the
1434 error = VOP_OPEN(vp, FREAD, td->td_ucred, td, NULL);
1441 * Exec handler registration
1444 exec_register(execsw_arg)
1445 const struct execsw *execsw_arg;
1447 const struct execsw **es, **xs, **newexecsw;
1448 int count = 2; /* New slot and trailing NULL */
1451 for (es = execsw; *es; es++)
1453 newexecsw = malloc(count * sizeof(*es), M_TEMP, M_WAITOK);
1454 if (newexecsw == NULL)
1458 for (es = execsw; *es; es++)
1463 free(execsw, M_TEMP);
1469 exec_unregister(execsw_arg)
1470 const struct execsw *execsw_arg;
1472 const struct execsw **es, **xs, **newexecsw;
1476 panic("unregister with no handlers left?\n");
1478 for (es = execsw; *es; es++) {
1479 if (*es == execsw_arg)
1484 for (es = execsw; *es; es++)
1485 if (*es != execsw_arg)
1487 newexecsw = malloc(count * sizeof(*es), M_TEMP, M_WAITOK);
1488 if (newexecsw == NULL)
1491 for (es = execsw; *es; es++)
1492 if (*es != execsw_arg)
1496 free(execsw, M_TEMP);