29
30#include "opt_hwpmc_hooks.h"
31#include "opt_kdtrace.h"
32#include "opt_ktrace.h"
33#include "opt_vm.h"
34
35#include <sys/param.h>
36#include <sys/systm.h>
37#include <sys/eventhandler.h>
38#include <sys/lock.h>
39#include <sys/mutex.h>
40#include <sys/sysproto.h>
41#include <sys/signalvar.h>
42#include <sys/kernel.h>
43#include <sys/mount.h>
44#include <sys/filedesc.h>
45#include <sys/fcntl.h>
46#include <sys/acct.h>
47#include <sys/exec.h>
48#include <sys/imgact.h>
49#include <sys/imgact_elf.h>
50#include <sys/wait.h>
51#include <sys/malloc.h>
52#include <sys/priv.h>
53#include <sys/proc.h>
54#include <sys/pioctl.h>
55#include <sys/namei.h>
56#include <sys/resourcevar.h>
57#include <sys/sdt.h>
58#include <sys/sf_buf.h>
59#include <sys/syscallsubr.h>
60#include <sys/sysent.h>
61#include <sys/shm.h>
62#include <sys/sysctl.h>
63#include <sys/vnode.h>
64#include <sys/stat.h>
65#ifdef KTRACE
66#include <sys/ktrace.h>
67#endif
68
69#include <vm/vm.h>
70#include <vm/vm_param.h>
71#include <vm/pmap.h>
72#include <vm/vm_page.h>
73#include <vm/vm_map.h>
74#include <vm/vm_kern.h>
75#include <vm/vm_extern.h>
76#include <vm/vm_object.h>
77#include <vm/vm_pager.h>
78
79#ifdef HWPMC_HOOKS
80#include <sys/pmckern.h>
81#endif
82
83#include <machine/reg.h>
84
85#include <security/audit/audit.h>
86#include <security/mac/mac_framework.h>
87
88#ifdef KDTRACE_HOOKS
89#include <sys/dtrace_bsd.h>
90dtrace_execexit_func_t dtrace_fasttrap_exec;
91#endif
92
93SDT_PROVIDER_DECLARE(proc);
94SDT_PROBE_DEFINE(proc, kernel, , exec);
95SDT_PROBE_ARGTYPE(proc, kernel, , exec, 0, "char *");
96SDT_PROBE_DEFINE(proc, kernel, , exec_failure);
97SDT_PROBE_ARGTYPE(proc, kernel, , exec_failure, 0, "int");
98SDT_PROBE_DEFINE(proc, kernel, , exec_success);
99SDT_PROBE_ARGTYPE(proc, kernel, , exec_success, 0, "char *");
100
101MALLOC_DEFINE(M_PARGS, "proc-args", "Process arguments");
102
103static int sysctl_kern_ps_strings(SYSCTL_HANDLER_ARGS);
104static int sysctl_kern_usrstack(SYSCTL_HANDLER_ARGS);
105static int sysctl_kern_stackprot(SYSCTL_HANDLER_ARGS);
106static int do_execve(struct thread *td, struct image_args *args,
107 struct mac *mac_p);
108static void exec_free_args(struct image_args *);
109
110/* XXX This should be vm_size_t. */
111SYSCTL_PROC(_kern, KERN_PS_STRINGS, ps_strings, CTLTYPE_ULONG|CTLFLAG_RD,
112 NULL, 0, sysctl_kern_ps_strings, "LU", "");
113
114/* XXX This should be vm_size_t. */
115SYSCTL_PROC(_kern, KERN_USRSTACK, usrstack, CTLTYPE_ULONG|CTLFLAG_RD,
116 NULL, 0, sysctl_kern_usrstack, "LU", "");
117
118SYSCTL_PROC(_kern, OID_AUTO, stackprot, CTLTYPE_INT|CTLFLAG_RD,
119 NULL, 0, sysctl_kern_stackprot, "I", "");
120
121u_long ps_arg_cache_limit = PAGE_SIZE / 16;
122SYSCTL_ULONG(_kern, OID_AUTO, ps_arg_cache_limit, CTLFLAG_RW,
123 &ps_arg_cache_limit, 0, "");
124
125static int map_at_zero = 0;
126TUNABLE_INT("security.bsd.map_at_zero", &map_at_zero);
127SYSCTL_INT(_security_bsd, OID_AUTO, map_at_zero, CTLFLAG_RW, &map_at_zero, 0,
128 "Permit processes to map an object at virtual address 0.");
129
130static int
131sysctl_kern_ps_strings(SYSCTL_HANDLER_ARGS)
132{
133 struct proc *p;
134 int error;
135
136 p = curproc;
137#ifdef SCTL_MASK32
138 if (req->flags & SCTL_MASK32) {
139 unsigned int val;
140 val = (unsigned int)p->p_sysent->sv_psstrings;
141 error = SYSCTL_OUT(req, &val, sizeof(val));
142 } else
143#endif
144 error = SYSCTL_OUT(req, &p->p_sysent->sv_psstrings,
145 sizeof(p->p_sysent->sv_psstrings));
146 return error;
147}
148
149static int
150sysctl_kern_usrstack(SYSCTL_HANDLER_ARGS)
151{
152 struct proc *p;
153 int error;
154
155 p = curproc;
156#ifdef SCTL_MASK32
157 if (req->flags & SCTL_MASK32) {
158 unsigned int val;
159 val = (unsigned int)p->p_sysent->sv_usrstack;
160 error = SYSCTL_OUT(req, &val, sizeof(val));
161 } else
162#endif
163 error = SYSCTL_OUT(req, &p->p_sysent->sv_usrstack,
164 sizeof(p->p_sysent->sv_usrstack));
165 return error;
166}
167
168static int
169sysctl_kern_stackprot(SYSCTL_HANDLER_ARGS)
170{
171 struct proc *p;
172
173 p = curproc;
174 return (SYSCTL_OUT(req, &p->p_sysent->sv_stackprot,
175 sizeof(p->p_sysent->sv_stackprot)));
176}
177
178/*
179 * Each of the items is a pointer to a `const struct execsw', hence the
180 * double pointer here.
181 */
182static const struct execsw **execsw;
183
184#ifndef _SYS_SYSPROTO_H_
185struct execve_args {
186 char *fname;
187 char **argv;
188 char **envv;
189};
190#endif
191
192int
193execve(td, uap)
194 struct thread *td;
195 struct execve_args /* {
196 char *fname;
197 char **argv;
198 char **envv;
199 } */ *uap;
200{
201 int error;
202 struct image_args args;
203
204 error = exec_copyin_args(&args, uap->fname, UIO_USERSPACE,
205 uap->argv, uap->envv);
206 if (error == 0)
207 error = kern_execve(td, &args, NULL);
208 return (error);
209}
210
211#ifndef _SYS_SYSPROTO_H_
212struct fexecve_args {
213 int fd;
214 char **argv;
215 char **envv;
216}
217#endif
218int
219fexecve(struct thread *td, struct fexecve_args *uap)
220{
221 int error;
222 struct image_args args;
223
224 error = exec_copyin_args(&args, NULL, UIO_SYSSPACE,
225 uap->argv, uap->envv);
226 if (error == 0) {
227 args.fd = uap->fd;
228 error = kern_execve(td, &args, NULL);
229 }
230 return (error);
231}
232
233#ifndef _SYS_SYSPROTO_H_
234struct __mac_execve_args {
235 char *fname;
236 char **argv;
237 char **envv;
238 struct mac *mac_p;
239};
240#endif
241
242int
243__mac_execve(td, uap)
244 struct thread *td;
245 struct __mac_execve_args /* {
246 char *fname;
247 char **argv;
248 char **envv;
249 struct mac *mac_p;
250 } */ *uap;
251{
252#ifdef MAC
253 int error;
254 struct image_args args;
255
256 error = exec_copyin_args(&args, uap->fname, UIO_USERSPACE,
257 uap->argv, uap->envv);
258 if (error == 0)
259 error = kern_execve(td, &args, uap->mac_p);
260 return (error);
261#else
262 return (ENOSYS);
263#endif
264}
265
266/*
267 * XXX: kern_execve has the astonishing property of not always returning to
268 * the caller. If sufficiently bad things happen during the call to
269 * do_execve(), it can end up calling exit1(); as a result, callers must
270 * avoid doing anything which they might need to undo (e.g., allocating
271 * memory).
272 */
273int
274kern_execve(td, args, mac_p)
275 struct thread *td;
276 struct image_args *args;
277 struct mac *mac_p;
278{
279 struct proc *p = td->td_proc;
280 int error;
281
282 AUDIT_ARG_ARGV(args->begin_argv, args->argc,
283 args->begin_envv - args->begin_argv);
284 AUDIT_ARG_ENVV(args->begin_envv, args->envc,
285 args->endp - args->begin_envv);
286 if (p->p_flag & P_HADTHREADS) {
287 PROC_LOCK(p);
288 if (thread_single(SINGLE_BOUNDARY)) {
289 PROC_UNLOCK(p);
290 exec_free_args(args);
291 return (ERESTART); /* Try again later. */
292 }
293 PROC_UNLOCK(p);
294 }
295
296 error = do_execve(td, args, mac_p);
297
298 if (p->p_flag & P_HADTHREADS) {
299 PROC_LOCK(p);
300 /*
301 * If success, we upgrade to SINGLE_EXIT state to
302 * force other threads to suicide.
303 */
304 if (error == 0)
305 thread_single(SINGLE_EXIT);
306 else
307 thread_single_end();
308 PROC_UNLOCK(p);
309 }
310
311 return (error);
312}
313
314/*
315 * In-kernel implementation of execve(). All arguments are assumed to be
316 * userspace pointers from the passed thread.
317 */
318static int
319do_execve(td, args, mac_p)
320 struct thread *td;
321 struct image_args *args;
322 struct mac *mac_p;
323{
324 struct proc *p = td->td_proc;
325 struct nameidata nd;
326 struct ucred *newcred = NULL, *oldcred;
327 struct uidinfo *euip;
328 register_t *stack_base;
329 int error, i;
330 struct image_params image_params, *imgp;
331 struct vattr attr;
332 int (*img_first)(struct image_params *);
333 struct pargs *oldargs = NULL, *newargs = NULL;
334 struct sigacts *oldsigacts, *newsigacts;
335#ifdef KTRACE
336 struct vnode *tracevp = NULL;
337 struct ucred *tracecred = NULL;
338#endif
339 struct vnode *textvp = NULL, *binvp = NULL;
340 int credential_changing;
341 int vfslocked;
342 int textset;
343#ifdef MAC
344 struct label *interpvplabel = NULL;
345 int will_transition;
346#endif
347#ifdef HWPMC_HOOKS
348 struct pmckern_procexec pe;
349#endif
350 static const char fexecv_proc_title[] = "(fexecv)";
351
352 vfslocked = 0;
353 imgp = &image_params;
354
355 /*
356 * Lock the process and set the P_INEXEC flag to indicate that
357 * it should be left alone until we're done here. This is
358 * necessary to avoid race conditions - e.g. in ptrace() -
359 * that might allow a local user to illicitly obtain elevated
360 * privileges.
361 */
362 PROC_LOCK(p);
363 KASSERT((p->p_flag & P_INEXEC) == 0,
364 ("%s(): process already has P_INEXEC flag", __func__));
365 p->p_flag |= P_INEXEC;
366 PROC_UNLOCK(p);
367
368 /*
369 * Initialize part of the common data
370 */
371 imgp->proc = p;
372 imgp->execlabel = NULL;
373 imgp->attr = &attr;
374 imgp->entry_addr = 0;
375 imgp->vmspace_destroyed = 0;
376 imgp->interpreted = 0;
377 imgp->opened = 0;
378 imgp->interpreter_name = args->buf + PATH_MAX + ARG_MAX;
379 imgp->auxargs = NULL;
380 imgp->vp = NULL;
381 imgp->object = NULL;
382 imgp->firstpage = NULL;
383 imgp->ps_strings = 0;
384 imgp->auxarg_size = 0;
385 imgp->args = args;
386 imgp->execpath = imgp->freepath = NULL;
387 imgp->execpathp = 0;
388
389#ifdef MAC
390 error = mac_execve_enter(imgp, mac_p);
391 if (error)
392 goto exec_fail;
393#endif
394
395 imgp->image_header = NULL;
396
397 /*
398 * Translate the file name. namei() returns a vnode pointer
399 * in ni_vp amoung other things.
400 *
401 * XXXAUDIT: It would be desirable to also audit the name of the
402 * interpreter if this is an interpreted binary.
403 */
404 if (args->fname != NULL) {
405 NDINIT(&nd, LOOKUP, ISOPEN | LOCKLEAF | FOLLOW | SAVENAME
406 | MPSAFE | AUDITVNODE1, UIO_SYSSPACE, args->fname, td);
407 }
408
409 SDT_PROBE(proc, kernel, , exec, args->fname, 0, 0, 0, 0 );
410
411interpret:
412 if (args->fname != NULL) {
413 error = namei(&nd);
414 if (error)
415 goto exec_fail;
416
417 vfslocked = NDHASGIANT(&nd);
418 binvp = nd.ni_vp;
419 imgp->vp = binvp;
420 } else {
421 AUDIT_ARG_FD(args->fd);
422 error = fgetvp(td, args->fd, &binvp);
423 if (error)
424 goto exec_fail;
425 vfslocked = VFS_LOCK_GIANT(binvp->v_mount);
426 vn_lock(binvp, LK_EXCLUSIVE | LK_RETRY);
427 AUDIT_ARG_VNODE1(binvp);
428 imgp->vp = binvp;
429 }
430
431 /*
432 * Check file permissions (also 'opens' file)
433 */
434 error = exec_check_permissions(imgp);
435 if (error)
436 goto exec_fail_dealloc;
437
438 imgp->object = imgp->vp->v_object;
439 if (imgp->object != NULL)
440 vm_object_reference(imgp->object);
441
442 /*
443 * Set VV_TEXT now so no one can write to the executable while we're
444 * activating it.
445 *
446 * Remember if this was set before and unset it in case this is not
447 * actually an executable image.
448 */
449 textset = imgp->vp->v_vflag & VV_TEXT;
450 imgp->vp->v_vflag |= VV_TEXT;
451
452 error = exec_map_first_page(imgp);
453 if (error)
454 goto exec_fail_dealloc;
455
456 imgp->proc->p_osrel = 0;
457 /*
458 * If the current process has a special image activator it
459 * wants to try first, call it. For example, emulating shell
460 * scripts differently.
461 */
462 error = -1;
463 if ((img_first = imgp->proc->p_sysent->sv_imgact_try) != NULL)
464 error = img_first(imgp);
465
466 /*
467 * Loop through the list of image activators, calling each one.
468 * An activator returns -1 if there is no match, 0 on success,
469 * and an error otherwise.
470 */
471 for (i = 0; error == -1 && execsw[i]; ++i) {
472 if (execsw[i]->ex_imgact == NULL ||
473 execsw[i]->ex_imgact == img_first) {
474 continue;
475 }
476 error = (*execsw[i]->ex_imgact)(imgp);
477 }
478
479 if (error) {
480 if (error == -1) {
481 if (textset == 0)
482 imgp->vp->v_vflag &= ~VV_TEXT;
483 error = ENOEXEC;
484 }
485 goto exec_fail_dealloc;
486 }
487
488 /*
489 * Special interpreter operation, cleanup and loop up to try to
490 * activate the interpreter.
491 */
492 if (imgp->interpreted) {
493 exec_unmap_first_page(imgp);
494 /*
495 * VV_TEXT needs to be unset for scripts. There is a short
496 * period before we determine that something is a script where
497 * VV_TEXT will be set. The vnode lock is held over this
498 * entire period so nothing should illegitimately be blocked.
499 */
500 imgp->vp->v_vflag &= ~VV_TEXT;
501 /* free name buffer and old vnode */
502 if (args->fname != NULL)
503 NDFREE(&nd, NDF_ONLY_PNBUF);
504#ifdef MAC
505 mac_execve_interpreter_enter(binvp, &interpvplabel);
506#endif
507 if (imgp->opened) {
508 VOP_CLOSE(binvp, FREAD, td->td_ucred, td);
509 imgp->opened = 0;
510 }
511 vput(binvp);
512 vm_object_deallocate(imgp->object);
513 imgp->object = NULL;
514 VFS_UNLOCK_GIANT(vfslocked);
515 vfslocked = 0;
516 /* set new name to that of the interpreter */
517 NDINIT(&nd, LOOKUP, LOCKLEAF | FOLLOW | SAVENAME | MPSAFE,
518 UIO_SYSSPACE, imgp->interpreter_name, td);
519 args->fname = imgp->interpreter_name;
520 goto interpret;
521 }
522
523 /*
524 * NB: We unlock the vnode here because it is believed that none
525 * of the sv_copyout_strings/sv_fixup operations require the vnode.
526 */
527 VOP_UNLOCK(imgp->vp, 0);
528
529 /*
530 * Do the best to calculate the full path to the image file.
531 */
532 if (imgp->auxargs != NULL &&
533 ((args->fname != NULL && args->fname[0] == '/') ||
534 vn_fullpath(td, imgp->vp, &imgp->execpath, &imgp->freepath) != 0))
535 imgp->execpath = args->fname;
536
537 /*
538 * Copy out strings (args and env) and initialize stack base
539 */
540 if (p->p_sysent->sv_copyout_strings)
541 stack_base = (*p->p_sysent->sv_copyout_strings)(imgp);
542 else
543 stack_base = exec_copyout_strings(imgp);
544
545 /*
546 * If custom stack fixup routine present for this process
547 * let it do the stack setup.
548 * Else stuff argument count as first item on stack
549 */
550 if (p->p_sysent->sv_fixup != NULL)
551 (*p->p_sysent->sv_fixup)(&stack_base, imgp);
552 else
553 suword(--stack_base, imgp->args->argc);
554
555 /*
556 * For security and other reasons, the file descriptor table cannot
557 * be shared after an exec.
558 */
559 fdunshare(p, td);
560
561 /*
562 * Malloc things before we need locks.
563 */
564 newcred = crget();
565 euip = uifind(attr.va_uid);
566 i = imgp->args->begin_envv - imgp->args->begin_argv;
567 /* Cache arguments if they fit inside our allowance */
568 if (ps_arg_cache_limit >= i + sizeof(struct pargs)) {
569 newargs = pargs_alloc(i);
570 bcopy(imgp->args->begin_argv, newargs->ar_args, i);
571 }
572
573 /* close files on exec */
574 fdcloseexec(td);
575 vn_lock(imgp->vp, LK_EXCLUSIVE | LK_RETRY);
576
577 /* Get a reference to the vnode prior to locking the proc */
578 VREF(binvp);
579
580 /*
581 * For security and other reasons, signal handlers cannot
582 * be shared after an exec. The new process gets a copy of the old
583 * handlers. In execsigs(), the new process will have its signals
584 * reset.
585 */
586 PROC_LOCK(p);
587 oldcred = crcopysafe(p, newcred);
588 if (sigacts_shared(p->p_sigacts)) {
589 oldsigacts = p->p_sigacts;
590 PROC_UNLOCK(p);
591 newsigacts = sigacts_alloc();
592 sigacts_copy(newsigacts, oldsigacts);
593 PROC_LOCK(p);
594 p->p_sigacts = newsigacts;
595 } else
596 oldsigacts = NULL;
597
598 /* Stop profiling */
599 stopprofclock(p);
600
601 /* reset caught signals */
602 execsigs(p);
603
604 /* name this process - nameiexec(p, ndp) */
605 bzero(p->p_comm, sizeof(p->p_comm));
606 if (args->fname)
607 bcopy(nd.ni_cnd.cn_nameptr, p->p_comm,
608 min(nd.ni_cnd.cn_namelen, MAXCOMLEN));
609 else if (vn_commname(binvp, p->p_comm, sizeof(p->p_comm)) != 0)
610 bcopy(fexecv_proc_title, p->p_comm, sizeof(fexecv_proc_title));
611 bcopy(p->p_comm, td->td_name, sizeof(td->td_name));
612
613 /*
614 * mark as execed, wakeup the process that vforked (if any) and tell
615 * it that it now has its own resources back
616 */
617 p->p_flag |= P_EXEC;
618 if (p->p_pptr && (p->p_flag & P_PPWAIT)) {
619 p->p_flag &= ~P_PPWAIT;
620 cv_broadcast(&p->p_pwait);
621 }
622
623 /*
624 * Implement image setuid/setgid.
625 *
626 * Don't honor setuid/setgid if the filesystem prohibits it or if
627 * the process is being traced.
628 *
629 * XXXMAC: For the time being, use NOSUID to also prohibit
630 * transitions on the file system.
631 */
632 credential_changing = 0;
633 credential_changing |= (attr.va_mode & S_ISUID) && oldcred->cr_uid !=
634 attr.va_uid;
635 credential_changing |= (attr.va_mode & S_ISGID) && oldcred->cr_gid !=
636 attr.va_gid;
637#ifdef MAC
638 will_transition = mac_vnode_execve_will_transition(oldcred, imgp->vp,
639 interpvplabel, imgp);
640 credential_changing |= will_transition;
641#endif
642
643 if (credential_changing &&
644 (imgp->vp->v_mount->mnt_flag & MNT_NOSUID) == 0 &&
645 (p->p_flag & P_TRACED) == 0) {
646 /*
647 * Turn off syscall tracing for set-id programs, except for
648 * root. Record any set-id flags first to make sure that
649 * we do not regain any tracing during a possible block.
650 */
651 setsugid(p);
652
653#ifdef KTRACE
654 if (p->p_tracevp != NULL &&
655 priv_check_cred(oldcred, PRIV_DEBUG_DIFFCRED, 0)) {
656 mtx_lock(&ktrace_mtx);
657 p->p_traceflag = 0;
658 tracevp = p->p_tracevp;
659 p->p_tracevp = NULL;
660 tracecred = p->p_tracecred;
661 p->p_tracecred = NULL;
662 mtx_unlock(&ktrace_mtx);
663 }
664#endif
665 /*
666 * Close any file descriptors 0..2 that reference procfs,
667 * then make sure file descriptors 0..2 are in use.
668 *
669 * setugidsafety() may call closef() and then pfind()
670 * which may grab the process lock.
671 * fdcheckstd() may call falloc() which may block to
672 * allocate memory, so temporarily drop the process lock.
673 */
674 PROC_UNLOCK(p);
675 VOP_UNLOCK(imgp->vp, 0);
676 setugidsafety(td);
677 error = fdcheckstd(td);
678 vn_lock(imgp->vp, LK_EXCLUSIVE | LK_RETRY);
679 if (error != 0)
680 goto done1;
681 PROC_LOCK(p);
682 /*
683 * Set the new credentials.
684 */
685 if (attr.va_mode & S_ISUID)
686 change_euid(newcred, euip);
687 if (attr.va_mode & S_ISGID)
688 change_egid(newcred, attr.va_gid);
689#ifdef MAC
690 if (will_transition) {
691 mac_vnode_execve_transition(oldcred, newcred, imgp->vp,
692 interpvplabel, imgp);
693 }
694#endif
695 /*
696 * Implement correct POSIX saved-id behavior.
697 *
698 * XXXMAC: Note that the current logic will save the
699 * uid and gid if a MAC domain transition occurs, even
700 * though maybe it shouldn't.
701 */
702 change_svuid(newcred, newcred->cr_uid);
703 change_svgid(newcred, newcred->cr_gid);
704 p->p_ucred = newcred;
705 newcred = NULL;
706 } else {
707 if (oldcred->cr_uid == oldcred->cr_ruid &&
708 oldcred->cr_gid == oldcred->cr_rgid)
709 p->p_flag &= ~P_SUGID;
710 /*
711 * Implement correct POSIX saved-id behavior.
712 *
713 * XXX: It's not clear that the existing behavior is
714 * POSIX-compliant. A number of sources indicate that the
715 * saved uid/gid should only be updated if the new ruid is
716 * not equal to the old ruid, or the new euid is not equal
717 * to the old euid and the new euid is not equal to the old
718 * ruid. The FreeBSD code always updates the saved uid/gid.
719 * Also, this code uses the new (replaced) euid and egid as
720 * the source, which may or may not be the right ones to use.
721 */
722 if (oldcred->cr_svuid != oldcred->cr_uid ||
723 oldcred->cr_svgid != oldcred->cr_gid) {
724 change_svuid(newcred, newcred->cr_uid);
725 change_svgid(newcred, newcred->cr_gid);
726 p->p_ucred = newcred;
727 newcred = NULL;
728 }
729 }
730
731 /*
732 * Store the vp for use in procfs. This vnode was referenced prior
733 * to locking the proc lock.
734 */
735 textvp = p->p_textvp;
736 p->p_textvp = binvp;
737
738#ifdef KDTRACE_HOOKS
739 /*
740 * Tell the DTrace fasttrap provider about the exec if it
741 * has declared an interest.
742 */
743 if (dtrace_fasttrap_exec)
744 dtrace_fasttrap_exec(p);
745#endif
746
747 /*
748 * Notify others that we exec'd, and clear the P_INEXEC flag
749 * as we're now a bona fide freshly-execed process.
750 */
751 KNOTE_LOCKED(&p->p_klist, NOTE_EXEC);
752 p->p_flag &= ~P_INEXEC;
753
754 /*
755 * If tracing the process, trap to debugger so breakpoints
756 * can be set before the program executes.
757 * Use tdsignal to deliver signal to current thread, use
758 * psignal may cause the signal to be delivered to wrong thread
759 * because that thread will exit, remember we are going to enter
760 * single thread mode.
761 */
762 if (p->p_flag & P_TRACED)
763 tdsignal(p, td, SIGTRAP, NULL);
764
765 /* clear "fork but no exec" flag, as we _are_ execing */
766 p->p_acflag &= ~AFORK;
767
768 /*
769 * Free any previous argument cache and replace it with
770 * the new argument cache, if any.
771 */
772 oldargs = p->p_args;
773 p->p_args = newargs;
774 newargs = NULL;
775
776#ifdef HWPMC_HOOKS
777 /*
778 * Check if system-wide sampling is in effect or if the
779 * current process is using PMCs. If so, do exec() time
780 * processing. This processing needs to happen AFTER the
781 * P_INEXEC flag is cleared.
782 *
783 * The proc lock needs to be released before taking the PMC
784 * SX.
785 */
786 if (PMC_SYSTEM_SAMPLING_ACTIVE() || PMC_PROC_IS_USING_PMCS(p)) {
787 PROC_UNLOCK(p);
788 VOP_UNLOCK(imgp->vp, 0);
789 pe.pm_credentialschanged = credential_changing;
790 pe.pm_entryaddr = imgp->entry_addr;
791
792 PMC_CALL_HOOK_X(td, PMC_FN_PROCESS_EXEC, (void *) &pe);
793 vn_lock(imgp->vp, LK_EXCLUSIVE | LK_RETRY);
794 } else
795 PROC_UNLOCK(p);
796#else /* !HWPMC_HOOKS */
797 PROC_UNLOCK(p);
798#endif
799
800 /* Set values passed into the program in registers. */
801 if (p->p_sysent->sv_setregs)
| 29
30#include "opt_hwpmc_hooks.h"
31#include "opt_kdtrace.h"
32#include "opt_ktrace.h"
33#include "opt_vm.h"
34
35#include <sys/param.h>
36#include <sys/systm.h>
37#include <sys/eventhandler.h>
38#include <sys/lock.h>
39#include <sys/mutex.h>
40#include <sys/sysproto.h>
41#include <sys/signalvar.h>
42#include <sys/kernel.h>
43#include <sys/mount.h>
44#include <sys/filedesc.h>
45#include <sys/fcntl.h>
46#include <sys/acct.h>
47#include <sys/exec.h>
48#include <sys/imgact.h>
49#include <sys/imgact_elf.h>
50#include <sys/wait.h>
51#include <sys/malloc.h>
52#include <sys/priv.h>
53#include <sys/proc.h>
54#include <sys/pioctl.h>
55#include <sys/namei.h>
56#include <sys/resourcevar.h>
57#include <sys/sdt.h>
58#include <sys/sf_buf.h>
59#include <sys/syscallsubr.h>
60#include <sys/sysent.h>
61#include <sys/shm.h>
62#include <sys/sysctl.h>
63#include <sys/vnode.h>
64#include <sys/stat.h>
65#ifdef KTRACE
66#include <sys/ktrace.h>
67#endif
68
69#include <vm/vm.h>
70#include <vm/vm_param.h>
71#include <vm/pmap.h>
72#include <vm/vm_page.h>
73#include <vm/vm_map.h>
74#include <vm/vm_kern.h>
75#include <vm/vm_extern.h>
76#include <vm/vm_object.h>
77#include <vm/vm_pager.h>
78
79#ifdef HWPMC_HOOKS
80#include <sys/pmckern.h>
81#endif
82
83#include <machine/reg.h>
84
85#include <security/audit/audit.h>
86#include <security/mac/mac_framework.h>
87
88#ifdef KDTRACE_HOOKS
89#include <sys/dtrace_bsd.h>
90dtrace_execexit_func_t dtrace_fasttrap_exec;
91#endif
92
93SDT_PROVIDER_DECLARE(proc);
94SDT_PROBE_DEFINE(proc, kernel, , exec);
95SDT_PROBE_ARGTYPE(proc, kernel, , exec, 0, "char *");
96SDT_PROBE_DEFINE(proc, kernel, , exec_failure);
97SDT_PROBE_ARGTYPE(proc, kernel, , exec_failure, 0, "int");
98SDT_PROBE_DEFINE(proc, kernel, , exec_success);
99SDT_PROBE_ARGTYPE(proc, kernel, , exec_success, 0, "char *");
100
101MALLOC_DEFINE(M_PARGS, "proc-args", "Process arguments");
102
103static int sysctl_kern_ps_strings(SYSCTL_HANDLER_ARGS);
104static int sysctl_kern_usrstack(SYSCTL_HANDLER_ARGS);
105static int sysctl_kern_stackprot(SYSCTL_HANDLER_ARGS);
106static int do_execve(struct thread *td, struct image_args *args,
107 struct mac *mac_p);
108static void exec_free_args(struct image_args *);
109
110/* XXX This should be vm_size_t. */
111SYSCTL_PROC(_kern, KERN_PS_STRINGS, ps_strings, CTLTYPE_ULONG|CTLFLAG_RD,
112 NULL, 0, sysctl_kern_ps_strings, "LU", "");
113
114/* XXX This should be vm_size_t. */
115SYSCTL_PROC(_kern, KERN_USRSTACK, usrstack, CTLTYPE_ULONG|CTLFLAG_RD,
116 NULL, 0, sysctl_kern_usrstack, "LU", "");
117
118SYSCTL_PROC(_kern, OID_AUTO, stackprot, CTLTYPE_INT|CTLFLAG_RD,
119 NULL, 0, sysctl_kern_stackprot, "I", "");
120
121u_long ps_arg_cache_limit = PAGE_SIZE / 16;
122SYSCTL_ULONG(_kern, OID_AUTO, ps_arg_cache_limit, CTLFLAG_RW,
123 &ps_arg_cache_limit, 0, "");
124
125static int map_at_zero = 0;
126TUNABLE_INT("security.bsd.map_at_zero", &map_at_zero);
127SYSCTL_INT(_security_bsd, OID_AUTO, map_at_zero, CTLFLAG_RW, &map_at_zero, 0,
128 "Permit processes to map an object at virtual address 0.");
129
130static int
131sysctl_kern_ps_strings(SYSCTL_HANDLER_ARGS)
132{
133 struct proc *p;
134 int error;
135
136 p = curproc;
137#ifdef SCTL_MASK32
138 if (req->flags & SCTL_MASK32) {
139 unsigned int val;
140 val = (unsigned int)p->p_sysent->sv_psstrings;
141 error = SYSCTL_OUT(req, &val, sizeof(val));
142 } else
143#endif
144 error = SYSCTL_OUT(req, &p->p_sysent->sv_psstrings,
145 sizeof(p->p_sysent->sv_psstrings));
146 return error;
147}
148
149static int
150sysctl_kern_usrstack(SYSCTL_HANDLER_ARGS)
151{
152 struct proc *p;
153 int error;
154
155 p = curproc;
156#ifdef SCTL_MASK32
157 if (req->flags & SCTL_MASK32) {
158 unsigned int val;
159 val = (unsigned int)p->p_sysent->sv_usrstack;
160 error = SYSCTL_OUT(req, &val, sizeof(val));
161 } else
162#endif
163 error = SYSCTL_OUT(req, &p->p_sysent->sv_usrstack,
164 sizeof(p->p_sysent->sv_usrstack));
165 return error;
166}
167
168static int
169sysctl_kern_stackprot(SYSCTL_HANDLER_ARGS)
170{
171 struct proc *p;
172
173 p = curproc;
174 return (SYSCTL_OUT(req, &p->p_sysent->sv_stackprot,
175 sizeof(p->p_sysent->sv_stackprot)));
176}
177
178/*
179 * Each of the items is a pointer to a `const struct execsw', hence the
180 * double pointer here.
181 */
182static const struct execsw **execsw;
183
184#ifndef _SYS_SYSPROTO_H_
185struct execve_args {
186 char *fname;
187 char **argv;
188 char **envv;
189};
190#endif
191
192int
193execve(td, uap)
194 struct thread *td;
195 struct execve_args /* {
196 char *fname;
197 char **argv;
198 char **envv;
199 } */ *uap;
200{
201 int error;
202 struct image_args args;
203
204 error = exec_copyin_args(&args, uap->fname, UIO_USERSPACE,
205 uap->argv, uap->envv);
206 if (error == 0)
207 error = kern_execve(td, &args, NULL);
208 return (error);
209}
210
211#ifndef _SYS_SYSPROTO_H_
212struct fexecve_args {
213 int fd;
214 char **argv;
215 char **envv;
216}
217#endif
218int
219fexecve(struct thread *td, struct fexecve_args *uap)
220{
221 int error;
222 struct image_args args;
223
224 error = exec_copyin_args(&args, NULL, UIO_SYSSPACE,
225 uap->argv, uap->envv);
226 if (error == 0) {
227 args.fd = uap->fd;
228 error = kern_execve(td, &args, NULL);
229 }
230 return (error);
231}
232
233#ifndef _SYS_SYSPROTO_H_
234struct __mac_execve_args {
235 char *fname;
236 char **argv;
237 char **envv;
238 struct mac *mac_p;
239};
240#endif
241
242int
243__mac_execve(td, uap)
244 struct thread *td;
245 struct __mac_execve_args /* {
246 char *fname;
247 char **argv;
248 char **envv;
249 struct mac *mac_p;
250 } */ *uap;
251{
252#ifdef MAC
253 int error;
254 struct image_args args;
255
256 error = exec_copyin_args(&args, uap->fname, UIO_USERSPACE,
257 uap->argv, uap->envv);
258 if (error == 0)
259 error = kern_execve(td, &args, uap->mac_p);
260 return (error);
261#else
262 return (ENOSYS);
263#endif
264}
265
266/*
267 * XXX: kern_execve has the astonishing property of not always returning to
268 * the caller. If sufficiently bad things happen during the call to
269 * do_execve(), it can end up calling exit1(); as a result, callers must
270 * avoid doing anything which they might need to undo (e.g., allocating
271 * memory).
272 */
273int
274kern_execve(td, args, mac_p)
275 struct thread *td;
276 struct image_args *args;
277 struct mac *mac_p;
278{
279 struct proc *p = td->td_proc;
280 int error;
281
282 AUDIT_ARG_ARGV(args->begin_argv, args->argc,
283 args->begin_envv - args->begin_argv);
284 AUDIT_ARG_ENVV(args->begin_envv, args->envc,
285 args->endp - args->begin_envv);
286 if (p->p_flag & P_HADTHREADS) {
287 PROC_LOCK(p);
288 if (thread_single(SINGLE_BOUNDARY)) {
289 PROC_UNLOCK(p);
290 exec_free_args(args);
291 return (ERESTART); /* Try again later. */
292 }
293 PROC_UNLOCK(p);
294 }
295
296 error = do_execve(td, args, mac_p);
297
298 if (p->p_flag & P_HADTHREADS) {
299 PROC_LOCK(p);
300 /*
301 * If success, we upgrade to SINGLE_EXIT state to
302 * force other threads to suicide.
303 */
304 if (error == 0)
305 thread_single(SINGLE_EXIT);
306 else
307 thread_single_end();
308 PROC_UNLOCK(p);
309 }
310
311 return (error);
312}
313
314/*
315 * In-kernel implementation of execve(). All arguments are assumed to be
316 * userspace pointers from the passed thread.
317 */
318static int
319do_execve(td, args, mac_p)
320 struct thread *td;
321 struct image_args *args;
322 struct mac *mac_p;
323{
324 struct proc *p = td->td_proc;
325 struct nameidata nd;
326 struct ucred *newcred = NULL, *oldcred;
327 struct uidinfo *euip;
328 register_t *stack_base;
329 int error, i;
330 struct image_params image_params, *imgp;
331 struct vattr attr;
332 int (*img_first)(struct image_params *);
333 struct pargs *oldargs = NULL, *newargs = NULL;
334 struct sigacts *oldsigacts, *newsigacts;
335#ifdef KTRACE
336 struct vnode *tracevp = NULL;
337 struct ucred *tracecred = NULL;
338#endif
339 struct vnode *textvp = NULL, *binvp = NULL;
340 int credential_changing;
341 int vfslocked;
342 int textset;
343#ifdef MAC
344 struct label *interpvplabel = NULL;
345 int will_transition;
346#endif
347#ifdef HWPMC_HOOKS
348 struct pmckern_procexec pe;
349#endif
350 static const char fexecv_proc_title[] = "(fexecv)";
351
352 vfslocked = 0;
353 imgp = &image_params;
354
355 /*
356 * Lock the process and set the P_INEXEC flag to indicate that
357 * it should be left alone until we're done here. This is
358 * necessary to avoid race conditions - e.g. in ptrace() -
359 * that might allow a local user to illicitly obtain elevated
360 * privileges.
361 */
362 PROC_LOCK(p);
363 KASSERT((p->p_flag & P_INEXEC) == 0,
364 ("%s(): process already has P_INEXEC flag", __func__));
365 p->p_flag |= P_INEXEC;
366 PROC_UNLOCK(p);
367
368 /*
369 * Initialize part of the common data
370 */
371 imgp->proc = p;
372 imgp->execlabel = NULL;
373 imgp->attr = &attr;
374 imgp->entry_addr = 0;
375 imgp->vmspace_destroyed = 0;
376 imgp->interpreted = 0;
377 imgp->opened = 0;
378 imgp->interpreter_name = args->buf + PATH_MAX + ARG_MAX;
379 imgp->auxargs = NULL;
380 imgp->vp = NULL;
381 imgp->object = NULL;
382 imgp->firstpage = NULL;
383 imgp->ps_strings = 0;
384 imgp->auxarg_size = 0;
385 imgp->args = args;
386 imgp->execpath = imgp->freepath = NULL;
387 imgp->execpathp = 0;
388
389#ifdef MAC
390 error = mac_execve_enter(imgp, mac_p);
391 if (error)
392 goto exec_fail;
393#endif
394
395 imgp->image_header = NULL;
396
397 /*
398 * Translate the file name. namei() returns a vnode pointer
399 * in ni_vp amoung other things.
400 *
401 * XXXAUDIT: It would be desirable to also audit the name of the
402 * interpreter if this is an interpreted binary.
403 */
404 if (args->fname != NULL) {
405 NDINIT(&nd, LOOKUP, ISOPEN | LOCKLEAF | FOLLOW | SAVENAME
406 | MPSAFE | AUDITVNODE1, UIO_SYSSPACE, args->fname, td);
407 }
408
409 SDT_PROBE(proc, kernel, , exec, args->fname, 0, 0, 0, 0 );
410
411interpret:
412 if (args->fname != NULL) {
413 error = namei(&nd);
414 if (error)
415 goto exec_fail;
416
417 vfslocked = NDHASGIANT(&nd);
418 binvp = nd.ni_vp;
419 imgp->vp = binvp;
420 } else {
421 AUDIT_ARG_FD(args->fd);
422 error = fgetvp(td, args->fd, &binvp);
423 if (error)
424 goto exec_fail;
425 vfslocked = VFS_LOCK_GIANT(binvp->v_mount);
426 vn_lock(binvp, LK_EXCLUSIVE | LK_RETRY);
427 AUDIT_ARG_VNODE1(binvp);
428 imgp->vp = binvp;
429 }
430
431 /*
432 * Check file permissions (also 'opens' file)
433 */
434 error = exec_check_permissions(imgp);
435 if (error)
436 goto exec_fail_dealloc;
437
438 imgp->object = imgp->vp->v_object;
439 if (imgp->object != NULL)
440 vm_object_reference(imgp->object);
441
442 /*
443 * Set VV_TEXT now so no one can write to the executable while we're
444 * activating it.
445 *
446 * Remember if this was set before and unset it in case this is not
447 * actually an executable image.
448 */
449 textset = imgp->vp->v_vflag & VV_TEXT;
450 imgp->vp->v_vflag |= VV_TEXT;
451
452 error = exec_map_first_page(imgp);
453 if (error)
454 goto exec_fail_dealloc;
455
456 imgp->proc->p_osrel = 0;
457 /*
458 * If the current process has a special image activator it
459 * wants to try first, call it. For example, emulating shell
460 * scripts differently.
461 */
462 error = -1;
463 if ((img_first = imgp->proc->p_sysent->sv_imgact_try) != NULL)
464 error = img_first(imgp);
465
466 /*
467 * Loop through the list of image activators, calling each one.
468 * An activator returns -1 if there is no match, 0 on success,
469 * and an error otherwise.
470 */
471 for (i = 0; error == -1 && execsw[i]; ++i) {
472 if (execsw[i]->ex_imgact == NULL ||
473 execsw[i]->ex_imgact == img_first) {
474 continue;
475 }
476 error = (*execsw[i]->ex_imgact)(imgp);
477 }
478
479 if (error) {
480 if (error == -1) {
481 if (textset == 0)
482 imgp->vp->v_vflag &= ~VV_TEXT;
483 error = ENOEXEC;
484 }
485 goto exec_fail_dealloc;
486 }
487
488 /*
489 * Special interpreter operation, cleanup and loop up to try to
490 * activate the interpreter.
491 */
492 if (imgp->interpreted) {
493 exec_unmap_first_page(imgp);
494 /*
495 * VV_TEXT needs to be unset for scripts. There is a short
496 * period before we determine that something is a script where
497 * VV_TEXT will be set. The vnode lock is held over this
498 * entire period so nothing should illegitimately be blocked.
499 */
500 imgp->vp->v_vflag &= ~VV_TEXT;
501 /* free name buffer and old vnode */
502 if (args->fname != NULL)
503 NDFREE(&nd, NDF_ONLY_PNBUF);
504#ifdef MAC
505 mac_execve_interpreter_enter(binvp, &interpvplabel);
506#endif
507 if (imgp->opened) {
508 VOP_CLOSE(binvp, FREAD, td->td_ucred, td);
509 imgp->opened = 0;
510 }
511 vput(binvp);
512 vm_object_deallocate(imgp->object);
513 imgp->object = NULL;
514 VFS_UNLOCK_GIANT(vfslocked);
515 vfslocked = 0;
516 /* set new name to that of the interpreter */
517 NDINIT(&nd, LOOKUP, LOCKLEAF | FOLLOW | SAVENAME | MPSAFE,
518 UIO_SYSSPACE, imgp->interpreter_name, td);
519 args->fname = imgp->interpreter_name;
520 goto interpret;
521 }
522
523 /*
524 * NB: We unlock the vnode here because it is believed that none
525 * of the sv_copyout_strings/sv_fixup operations require the vnode.
526 */
527 VOP_UNLOCK(imgp->vp, 0);
528
529 /*
530 * Do the best to calculate the full path to the image file.
531 */
532 if (imgp->auxargs != NULL &&
533 ((args->fname != NULL && args->fname[0] == '/') ||
534 vn_fullpath(td, imgp->vp, &imgp->execpath, &imgp->freepath) != 0))
535 imgp->execpath = args->fname;
536
537 /*
538 * Copy out strings (args and env) and initialize stack base
539 */
540 if (p->p_sysent->sv_copyout_strings)
541 stack_base = (*p->p_sysent->sv_copyout_strings)(imgp);
542 else
543 stack_base = exec_copyout_strings(imgp);
544
545 /*
546 * If custom stack fixup routine present for this process
547 * let it do the stack setup.
548 * Else stuff argument count as first item on stack
549 */
550 if (p->p_sysent->sv_fixup != NULL)
551 (*p->p_sysent->sv_fixup)(&stack_base, imgp);
552 else
553 suword(--stack_base, imgp->args->argc);
554
555 /*
556 * For security and other reasons, the file descriptor table cannot
557 * be shared after an exec.
558 */
559 fdunshare(p, td);
560
561 /*
562 * Malloc things before we need locks.
563 */
564 newcred = crget();
565 euip = uifind(attr.va_uid);
566 i = imgp->args->begin_envv - imgp->args->begin_argv;
567 /* Cache arguments if they fit inside our allowance */
568 if (ps_arg_cache_limit >= i + sizeof(struct pargs)) {
569 newargs = pargs_alloc(i);
570 bcopy(imgp->args->begin_argv, newargs->ar_args, i);
571 }
572
573 /* close files on exec */
574 fdcloseexec(td);
575 vn_lock(imgp->vp, LK_EXCLUSIVE | LK_RETRY);
576
577 /* Get a reference to the vnode prior to locking the proc */
578 VREF(binvp);
579
580 /*
581 * For security and other reasons, signal handlers cannot
582 * be shared after an exec. The new process gets a copy of the old
583 * handlers. In execsigs(), the new process will have its signals
584 * reset.
585 */
586 PROC_LOCK(p);
587 oldcred = crcopysafe(p, newcred);
588 if (sigacts_shared(p->p_sigacts)) {
589 oldsigacts = p->p_sigacts;
590 PROC_UNLOCK(p);
591 newsigacts = sigacts_alloc();
592 sigacts_copy(newsigacts, oldsigacts);
593 PROC_LOCK(p);
594 p->p_sigacts = newsigacts;
595 } else
596 oldsigacts = NULL;
597
598 /* Stop profiling */
599 stopprofclock(p);
600
601 /* reset caught signals */
602 execsigs(p);
603
604 /* name this process - nameiexec(p, ndp) */
605 bzero(p->p_comm, sizeof(p->p_comm));
606 if (args->fname)
607 bcopy(nd.ni_cnd.cn_nameptr, p->p_comm,
608 min(nd.ni_cnd.cn_namelen, MAXCOMLEN));
609 else if (vn_commname(binvp, p->p_comm, sizeof(p->p_comm)) != 0)
610 bcopy(fexecv_proc_title, p->p_comm, sizeof(fexecv_proc_title));
611 bcopy(p->p_comm, td->td_name, sizeof(td->td_name));
612
613 /*
614 * mark as execed, wakeup the process that vforked (if any) and tell
615 * it that it now has its own resources back
616 */
617 p->p_flag |= P_EXEC;
618 if (p->p_pptr && (p->p_flag & P_PPWAIT)) {
619 p->p_flag &= ~P_PPWAIT;
620 cv_broadcast(&p->p_pwait);
621 }
622
623 /*
624 * Implement image setuid/setgid.
625 *
626 * Don't honor setuid/setgid if the filesystem prohibits it or if
627 * the process is being traced.
628 *
629 * XXXMAC: For the time being, use NOSUID to also prohibit
630 * transitions on the file system.
631 */
632 credential_changing = 0;
633 credential_changing |= (attr.va_mode & S_ISUID) && oldcred->cr_uid !=
634 attr.va_uid;
635 credential_changing |= (attr.va_mode & S_ISGID) && oldcred->cr_gid !=
636 attr.va_gid;
637#ifdef MAC
638 will_transition = mac_vnode_execve_will_transition(oldcred, imgp->vp,
639 interpvplabel, imgp);
640 credential_changing |= will_transition;
641#endif
642
643 if (credential_changing &&
644 (imgp->vp->v_mount->mnt_flag & MNT_NOSUID) == 0 &&
645 (p->p_flag & P_TRACED) == 0) {
646 /*
647 * Turn off syscall tracing for set-id programs, except for
648 * root. Record any set-id flags first to make sure that
649 * we do not regain any tracing during a possible block.
650 */
651 setsugid(p);
652
653#ifdef KTRACE
654 if (p->p_tracevp != NULL &&
655 priv_check_cred(oldcred, PRIV_DEBUG_DIFFCRED, 0)) {
656 mtx_lock(&ktrace_mtx);
657 p->p_traceflag = 0;
658 tracevp = p->p_tracevp;
659 p->p_tracevp = NULL;
660 tracecred = p->p_tracecred;
661 p->p_tracecred = NULL;
662 mtx_unlock(&ktrace_mtx);
663 }
664#endif
665 /*
666 * Close any file descriptors 0..2 that reference procfs,
667 * then make sure file descriptors 0..2 are in use.
668 *
669 * setugidsafety() may call closef() and then pfind()
670 * which may grab the process lock.
671 * fdcheckstd() may call falloc() which may block to
672 * allocate memory, so temporarily drop the process lock.
673 */
674 PROC_UNLOCK(p);
675 VOP_UNLOCK(imgp->vp, 0);
676 setugidsafety(td);
677 error = fdcheckstd(td);
678 vn_lock(imgp->vp, LK_EXCLUSIVE | LK_RETRY);
679 if (error != 0)
680 goto done1;
681 PROC_LOCK(p);
682 /*
683 * Set the new credentials.
684 */
685 if (attr.va_mode & S_ISUID)
686 change_euid(newcred, euip);
687 if (attr.va_mode & S_ISGID)
688 change_egid(newcred, attr.va_gid);
689#ifdef MAC
690 if (will_transition) {
691 mac_vnode_execve_transition(oldcred, newcred, imgp->vp,
692 interpvplabel, imgp);
693 }
694#endif
695 /*
696 * Implement correct POSIX saved-id behavior.
697 *
698 * XXXMAC: Note that the current logic will save the
699 * uid and gid if a MAC domain transition occurs, even
700 * though maybe it shouldn't.
701 */
702 change_svuid(newcred, newcred->cr_uid);
703 change_svgid(newcred, newcred->cr_gid);
704 p->p_ucred = newcred;
705 newcred = NULL;
706 } else {
707 if (oldcred->cr_uid == oldcred->cr_ruid &&
708 oldcred->cr_gid == oldcred->cr_rgid)
709 p->p_flag &= ~P_SUGID;
710 /*
711 * Implement correct POSIX saved-id behavior.
712 *
713 * XXX: It's not clear that the existing behavior is
714 * POSIX-compliant. A number of sources indicate that the
715 * saved uid/gid should only be updated if the new ruid is
716 * not equal to the old ruid, or the new euid is not equal
717 * to the old euid and the new euid is not equal to the old
718 * ruid. The FreeBSD code always updates the saved uid/gid.
719 * Also, this code uses the new (replaced) euid and egid as
720 * the source, which may or may not be the right ones to use.
721 */
722 if (oldcred->cr_svuid != oldcred->cr_uid ||
723 oldcred->cr_svgid != oldcred->cr_gid) {
724 change_svuid(newcred, newcred->cr_uid);
725 change_svgid(newcred, newcred->cr_gid);
726 p->p_ucred = newcred;
727 newcred = NULL;
728 }
729 }
730
731 /*
732 * Store the vp for use in procfs. This vnode was referenced prior
733 * to locking the proc lock.
734 */
735 textvp = p->p_textvp;
736 p->p_textvp = binvp;
737
738#ifdef KDTRACE_HOOKS
739 /*
740 * Tell the DTrace fasttrap provider about the exec if it
741 * has declared an interest.
742 */
743 if (dtrace_fasttrap_exec)
744 dtrace_fasttrap_exec(p);
745#endif
746
747 /*
748 * Notify others that we exec'd, and clear the P_INEXEC flag
749 * as we're now a bona fide freshly-execed process.
750 */
751 KNOTE_LOCKED(&p->p_klist, NOTE_EXEC);
752 p->p_flag &= ~P_INEXEC;
753
754 /*
755 * If tracing the process, trap to debugger so breakpoints
756 * can be set before the program executes.
757 * Use tdsignal to deliver signal to current thread, use
758 * psignal may cause the signal to be delivered to wrong thread
759 * because that thread will exit, remember we are going to enter
760 * single thread mode.
761 */
762 if (p->p_flag & P_TRACED)
763 tdsignal(p, td, SIGTRAP, NULL);
764
765 /* clear "fork but no exec" flag, as we _are_ execing */
766 p->p_acflag &= ~AFORK;
767
768 /*
769 * Free any previous argument cache and replace it with
770 * the new argument cache, if any.
771 */
772 oldargs = p->p_args;
773 p->p_args = newargs;
774 newargs = NULL;
775
776#ifdef HWPMC_HOOKS
777 /*
778 * Check if system-wide sampling is in effect or if the
779 * current process is using PMCs. If so, do exec() time
780 * processing. This processing needs to happen AFTER the
781 * P_INEXEC flag is cleared.
782 *
783 * The proc lock needs to be released before taking the PMC
784 * SX.
785 */
786 if (PMC_SYSTEM_SAMPLING_ACTIVE() || PMC_PROC_IS_USING_PMCS(p)) {
787 PROC_UNLOCK(p);
788 VOP_UNLOCK(imgp->vp, 0);
789 pe.pm_credentialschanged = credential_changing;
790 pe.pm_entryaddr = imgp->entry_addr;
791
792 PMC_CALL_HOOK_X(td, PMC_FN_PROCESS_EXEC, (void *) &pe);
793 vn_lock(imgp->vp, LK_EXCLUSIVE | LK_RETRY);
794 } else
795 PROC_UNLOCK(p);
796#else /* !HWPMC_HOOKS */
797 PROC_UNLOCK(p);
798#endif
799
800 /* Set values passed into the program in registers. */
801 if (p->p_sysent->sv_setregs)
|
807
808 vfs_mark_atime(imgp->vp, td->td_ucred);
809
810 SDT_PROBE(proc, kernel, , exec_success, args->fname, 0, 0, 0, 0);
811
812done1:
813 /*
814 * Free any resources malloc'd earlier that we didn't use.
815 */
816 uifree(euip);
817 if (newcred == NULL)
818 crfree(oldcred);
819 else
820 crfree(newcred);
821 VOP_UNLOCK(imgp->vp, 0);
822
823 /*
824 * Handle deferred decrement of ref counts.
825 */
826 if (textvp != NULL) {
827 int tvfslocked;
828
829 tvfslocked = VFS_LOCK_GIANT(textvp->v_mount);
830 vrele(textvp);
831 VFS_UNLOCK_GIANT(tvfslocked);
832 }
833 if (binvp && error != 0)
834 vrele(binvp);
835#ifdef KTRACE
836 if (tracevp != NULL) {
837 int tvfslocked;
838
839 tvfslocked = VFS_LOCK_GIANT(tracevp->v_mount);
840 vrele(tracevp);
841 VFS_UNLOCK_GIANT(tvfslocked);
842 }
843 if (tracecred != NULL)
844 crfree(tracecred);
845#endif
846 vn_lock(imgp->vp, LK_EXCLUSIVE | LK_RETRY);
847 pargs_drop(oldargs);
848 pargs_drop(newargs);
849 if (oldsigacts != NULL)
850 sigacts_free(oldsigacts);
851
852exec_fail_dealloc:
853
854 /*
855 * free various allocated resources
856 */
857 if (imgp->firstpage != NULL)
858 exec_unmap_first_page(imgp);
859
860 if (imgp->vp != NULL) {
861 if (args->fname)
862 NDFREE(&nd, NDF_ONLY_PNBUF);
863 if (imgp->opened)
864 VOP_CLOSE(imgp->vp, FREAD, td->td_ucred, td);
865 vput(imgp->vp);
866 }
867
868 if (imgp->object != NULL)
869 vm_object_deallocate(imgp->object);
870
871 free(imgp->freepath, M_TEMP);
872
873 if (error == 0) {
874 /*
875 * Stop the process here if its stop event mask has
876 * the S_EXEC bit set.
877 */
878 STOPEVENT(p, S_EXEC, 0);
879 goto done2;
880 }
881
882exec_fail:
883 /* we're done here, clear P_INEXEC */
884 PROC_LOCK(p);
885 p->p_flag &= ~P_INEXEC;
886 PROC_UNLOCK(p);
887
888 SDT_PROBE(proc, kernel, , exec_failure, error, 0, 0, 0, 0);
889
890done2:
891#ifdef MAC
892 mac_execve_exit(imgp);
893 mac_execve_interpreter_exit(interpvplabel);
894#endif
895 VFS_UNLOCK_GIANT(vfslocked);
896 exec_free_args(args);
897
898 if (error && imgp->vmspace_destroyed) {
899 /* sorry, no more process anymore. exit gracefully */
900 exit1(td, W_EXITCODE(0, SIGABRT));
901 /* NOT REACHED */
902 }
903 return (error);
904}
905
906int
907exec_map_first_page(imgp)
908 struct image_params *imgp;
909{
910 int rv, i;
911 int initial_pagein;
912 vm_page_t ma[VM_INITIAL_PAGEIN];
913 vm_object_t object;
914
915 if (imgp->firstpage != NULL)
916 exec_unmap_first_page(imgp);
917
918 object = imgp->vp->v_object;
919 if (object == NULL)
920 return (EACCES);
921 VM_OBJECT_LOCK(object);
922#if VM_NRESERVLEVEL > 0
923 if ((object->flags & OBJ_COLORED) == 0) {
924 object->flags |= OBJ_COLORED;
925 object->pg_color = 0;
926 }
927#endif
928 ma[0] = vm_page_grab(object, 0, VM_ALLOC_NORMAL | VM_ALLOC_RETRY);
929 if (ma[0]->valid != VM_PAGE_BITS_ALL) {
930 initial_pagein = VM_INITIAL_PAGEIN;
931 if (initial_pagein > object->size)
932 initial_pagein = object->size;
933 for (i = 1; i < initial_pagein; i++) {
934 if ((ma[i] = vm_page_lookup(object, i)) != NULL) {
935 if (ma[i]->valid)
936 break;
937 if ((ma[i]->oflags & VPO_BUSY) || ma[i]->busy)
938 break;
939 vm_page_busy(ma[i]);
940 } else {
941 ma[i] = vm_page_alloc(object, i,
942 VM_ALLOC_NORMAL | VM_ALLOC_IFNOTCACHED);
943 if (ma[i] == NULL)
944 break;
945 }
946 }
947 initial_pagein = i;
948 rv = vm_pager_get_pages(object, ma, initial_pagein, 0);
949 ma[0] = vm_page_lookup(object, 0);
950 if ((rv != VM_PAGER_OK) || (ma[0] == NULL)) {
951 if (ma[0]) {
952 vm_page_lock_queues();
953 vm_page_free(ma[0]);
954 vm_page_unlock_queues();
955 }
956 VM_OBJECT_UNLOCK(object);
957 return (EIO);
958 }
959 }
960 vm_page_lock_queues();
961 vm_page_hold(ma[0]);
962 vm_page_unlock_queues();
963 vm_page_wakeup(ma[0]);
964 VM_OBJECT_UNLOCK(object);
965
966 imgp->firstpage = sf_buf_alloc(ma[0], 0);
967 imgp->image_header = (char *)sf_buf_kva(imgp->firstpage);
968
969 return (0);
970}
971
972void
973exec_unmap_first_page(imgp)
974 struct image_params *imgp;
975{
976 vm_page_t m;
977
978 if (imgp->firstpage != NULL) {
979 m = sf_buf_page(imgp->firstpage);
980 sf_buf_free(imgp->firstpage);
981 imgp->firstpage = NULL;
982 vm_page_lock_queues();
983 vm_page_unhold(m);
984 vm_page_unlock_queues();
985 }
986}
987
988/*
989 * Destroy old address space, and allocate a new stack
990 * The new stack is only SGROWSIZ large because it is grown
991 * automatically in trap.c.
992 */
993int
994exec_new_vmspace(imgp, sv)
995 struct image_params *imgp;
996 struct sysentvec *sv;
997{
998 int error;
999 struct proc *p = imgp->proc;
1000 struct vmspace *vmspace = p->p_vmspace;
1001 vm_offset_t sv_minuser, stack_addr;
1002 vm_map_t map;
1003 u_long ssiz;
1004
1005 imgp->vmspace_destroyed = 1;
1006 imgp->sysent = sv;
1007
1008 /* May be called with Giant held */
1009 EVENTHANDLER_INVOKE(process_exec, p, imgp);
1010
1011 /*
1012 * Blow away entire process VM, if address space not shared,
1013 * otherwise, create a new VM space so that other threads are
1014 * not disrupted
1015 */
1016 map = &vmspace->vm_map;
1017 if (map_at_zero)
1018 sv_minuser = sv->sv_minuser;
1019 else
1020 sv_minuser = MAX(sv->sv_minuser, PAGE_SIZE);
1021 if (vmspace->vm_refcnt == 1 && vm_map_min(map) == sv_minuser &&
1022 vm_map_max(map) == sv->sv_maxuser) {
1023 shmexit(vmspace);
1024 pmap_remove_pages(vmspace_pmap(vmspace));
1025 vm_map_remove(map, vm_map_min(map), vm_map_max(map));
1026 } else {
1027 error = vmspace_exec(p, sv_minuser, sv->sv_maxuser);
1028 if (error)
1029 return (error);
1030 vmspace = p->p_vmspace;
1031 map = &vmspace->vm_map;
1032 }
1033
1034 /* Allocate a new stack */
1035 if (sv->sv_maxssiz != NULL)
1036 ssiz = *sv->sv_maxssiz;
1037 else
1038 ssiz = maxssiz;
1039 stack_addr = sv->sv_usrstack - ssiz;
1040 error = vm_map_stack(map, stack_addr, (vm_size_t)ssiz,
1041 sv->sv_stackprot, VM_PROT_ALL, MAP_STACK_GROWS_DOWN);
1042 if (error)
1043 return (error);
1044
1045#ifdef __ia64__
1046 /* Allocate a new register stack */
1047 stack_addr = IA64_BACKINGSTORE;
1048 error = vm_map_stack(map, stack_addr, (vm_size_t)ssiz,
1049 sv->sv_stackprot, VM_PROT_ALL, MAP_STACK_GROWS_UP);
1050 if (error)
1051 return (error);
1052#endif
1053
1054 /* vm_ssize and vm_maxsaddr are somewhat antiquated concepts in the
1055 * VM_STACK case, but they are still used to monitor the size of the
1056 * process stack so we can check the stack rlimit.
1057 */
1058 vmspace->vm_ssize = sgrowsiz >> PAGE_SHIFT;
1059 vmspace->vm_maxsaddr = (char *)sv->sv_usrstack - ssiz;
1060
1061 return (0);
1062}
1063
1064/*
1065 * Copy out argument and environment strings from the old process address
1066 * space into the temporary string buffer.
1067 */
1068int
1069exec_copyin_args(struct image_args *args, char *fname,
1070 enum uio_seg segflg, char **argv, char **envv)
1071{
1072 char *argp, *envp;
1073 int error;
1074 size_t length;
1075
1076 bzero(args, sizeof(*args));
1077 if (argv == NULL)
1078 return (EFAULT);
1079 /*
1080 * Allocate temporary demand zeroed space for argument and
1081 * environment strings:
1082 *
1083 * o ARG_MAX for argument and environment;
1084 * o MAXSHELLCMDLEN for the name of interpreters.
1085 */
1086 args->buf = (char *) kmem_alloc_wait(exec_map,
1087 PATH_MAX + ARG_MAX + MAXSHELLCMDLEN);
1088 if (args->buf == NULL)
1089 return (ENOMEM);
1090 args->begin_argv = args->buf;
1091 args->endp = args->begin_argv;
1092 args->stringspace = ARG_MAX;
1093 /*
1094 * Copy the file name.
1095 */
1096 if (fname != NULL) {
1097 args->fname = args->buf + ARG_MAX;
1098 error = (segflg == UIO_SYSSPACE) ?
1099 copystr(fname, args->fname, PATH_MAX, &length) :
1100 copyinstr(fname, args->fname, PATH_MAX, &length);
1101 if (error != 0)
1102 goto err_exit;
1103 } else
1104 args->fname = NULL;
1105
1106 /*
1107 * extract arguments first
1108 */
1109 while ((argp = (caddr_t) (intptr_t) fuword(argv++))) {
1110 if (argp == (caddr_t) -1) {
1111 error = EFAULT;
1112 goto err_exit;
1113 }
1114 if ((error = copyinstr(argp, args->endp,
1115 args->stringspace, &length))) {
1116 if (error == ENAMETOOLONG)
1117 error = E2BIG;
1118 goto err_exit;
1119 }
1120 args->stringspace -= length;
1121 args->endp += length;
1122 args->argc++;
1123 }
1124
1125 args->begin_envv = args->endp;
1126
1127 /*
1128 * extract environment strings
1129 */
1130 if (envv) {
1131 while ((envp = (caddr_t)(intptr_t)fuword(envv++))) {
1132 if (envp == (caddr_t)-1) {
1133 error = EFAULT;
1134 goto err_exit;
1135 }
1136 if ((error = copyinstr(envp, args->endp,
1137 args->stringspace, &length))) {
1138 if (error == ENAMETOOLONG)
1139 error = E2BIG;
1140 goto err_exit;
1141 }
1142 args->stringspace -= length;
1143 args->endp += length;
1144 args->envc++;
1145 }
1146 }
1147
1148 return (0);
1149
1150err_exit:
1151 exec_free_args(args);
1152 return (error);
1153}
1154
1155static void
1156exec_free_args(struct image_args *args)
1157{
1158
1159 if (args->buf) {
1160 kmem_free_wakeup(exec_map, (vm_offset_t)args->buf,
1161 PATH_MAX + ARG_MAX + MAXSHELLCMDLEN);
1162 args->buf = NULL;
1163 }
1164}
1165
1166/*
1167 * Copy strings out to the new process address space, constructing new arg
1168 * and env vector tables. Return a pointer to the base so that it can be used
1169 * as the initial stack pointer.
1170 */
1171register_t *
1172exec_copyout_strings(imgp)
1173 struct image_params *imgp;
1174{
1175 int argc, envc;
1176 char **vectp;
1177 char *stringp, *destp;
1178 register_t *stack_base;
1179 struct ps_strings *arginfo;
1180 struct proc *p;
1181 size_t execpath_len;
1182 int szsigcode;
1183
1184 /*
1185 * Calculate string base and vector table pointers.
1186 * Also deal with signal trampoline code for this exec type.
1187 */
1188 if (imgp->execpath != NULL && imgp->auxargs != NULL)
1189 execpath_len = strlen(imgp->execpath) + 1;
1190 else
1191 execpath_len = 0;
1192 p = imgp->proc;
1193 szsigcode = 0;
1194 arginfo = (struct ps_strings *)p->p_sysent->sv_psstrings;
1195 if (p->p_sysent->sv_szsigcode != NULL)
1196 szsigcode = *(p->p_sysent->sv_szsigcode);
1197 destp = (caddr_t)arginfo - szsigcode - SPARE_USRSPACE -
1198 roundup(execpath_len, sizeof(char *)) -
1199 roundup((ARG_MAX - imgp->args->stringspace), sizeof(char *));
1200
1201 /*
1202 * install sigcode
1203 */
1204 if (szsigcode)
1205 copyout(p->p_sysent->sv_sigcode, ((caddr_t)arginfo -
1206 szsigcode), szsigcode);
1207
1208 /*
1209 * Copy the image path for the rtld.
1210 */
1211 if (execpath_len != 0) {
1212 imgp->execpathp = (uintptr_t)arginfo - szsigcode - execpath_len;
1213 copyout(imgp->execpath, (void *)imgp->execpathp,
1214 execpath_len);
1215 }
1216
1217 /*
1218 * If we have a valid auxargs ptr, prepare some room
1219 * on the stack.
1220 */
1221 if (imgp->auxargs) {
1222 /*
1223 * 'AT_COUNT*2' is size for the ELF Auxargs data. This is for
1224 * lower compatibility.
1225 */
1226 imgp->auxarg_size = (imgp->auxarg_size) ? imgp->auxarg_size :
1227 (AT_COUNT * 2);
1228 /*
1229 * The '+ 2' is for the null pointers at the end of each of
1230 * the arg and env vector sets,and imgp->auxarg_size is room
1231 * for argument of Runtime loader.
1232 */
1233 vectp = (char **)(destp - (imgp->args->argc +
1234 imgp->args->envc + 2 + imgp->auxarg_size + execpath_len) *
1235 sizeof(char *));
1236 } else {
1237 /*
1238 * The '+ 2' is for the null pointers at the end of each of
1239 * the arg and env vector sets
1240 */
1241 vectp = (char **)(destp - (imgp->args->argc + imgp->args->envc + 2) *
1242 sizeof(char *));
1243 }
1244
1245 /*
1246 * vectp also becomes our initial stack base
1247 */
1248 stack_base = (register_t *)vectp;
1249
1250 stringp = imgp->args->begin_argv;
1251 argc = imgp->args->argc;
1252 envc = imgp->args->envc;
1253
1254 /*
1255 * Copy out strings - arguments and environment.
1256 */
1257 copyout(stringp, destp, ARG_MAX - imgp->args->stringspace);
1258
1259 /*
1260 * Fill in "ps_strings" struct for ps, w, etc.
1261 */
1262 suword(&arginfo->ps_argvstr, (long)(intptr_t)vectp);
1263 suword32(&arginfo->ps_nargvstr, argc);
1264
1265 /*
1266 * Fill in argument portion of vector table.
1267 */
1268 for (; argc > 0; --argc) {
1269 suword(vectp++, (long)(intptr_t)destp);
1270 while (*stringp++ != 0)
1271 destp++;
1272 destp++;
1273 }
1274
1275 /* a null vector table pointer separates the argp's from the envp's */
1276 suword(vectp++, 0);
1277
1278 suword(&arginfo->ps_envstr, (long)(intptr_t)vectp);
1279 suword32(&arginfo->ps_nenvstr, envc);
1280
1281 /*
1282 * Fill in environment portion of vector table.
1283 */
1284 for (; envc > 0; --envc) {
1285 suword(vectp++, (long)(intptr_t)destp);
1286 while (*stringp++ != 0)
1287 destp++;
1288 destp++;
1289 }
1290
1291 /* end of vector table is a null pointer */
1292 suword(vectp, 0);
1293
1294 return (stack_base);
1295}
1296
1297/*
1298 * Check permissions of file to execute.
1299 * Called with imgp->vp locked.
1300 * Return 0 for success or error code on failure.
1301 */
1302int
1303exec_check_permissions(imgp)
1304 struct image_params *imgp;
1305{
1306 struct vnode *vp = imgp->vp;
1307 struct vattr *attr = imgp->attr;
1308 struct thread *td;
1309 int error;
1310
1311 td = curthread;
1312
1313 /* Get file attributes */
1314 error = VOP_GETATTR(vp, attr, td->td_ucred);
1315 if (error)
1316 return (error);
1317
1318#ifdef MAC
1319 error = mac_vnode_check_exec(td->td_ucred, imgp->vp, imgp);
1320 if (error)
1321 return (error);
1322#endif
1323
1324 /*
1325 * 1) Check if file execution is disabled for the filesystem that this
1326 * file resides on.
1327 * 2) Insure that at least one execute bit is on - otherwise root
1328 * will always succeed, and we don't want to happen unless the
1329 * file really is executable.
1330 * 3) Insure that the file is a regular file.
1331 */
1332 if ((vp->v_mount->mnt_flag & MNT_NOEXEC) ||
1333 ((attr->va_mode & 0111) == 0) ||
1334 (attr->va_type != VREG))
1335 return (EACCES);
1336
1337 /*
1338 * Zero length files can't be exec'd
1339 */
1340 if (attr->va_size == 0)
1341 return (ENOEXEC);
1342
1343 /*
1344 * Check for execute permission to file based on current credentials.
1345 */
1346 error = VOP_ACCESS(vp, VEXEC, td->td_ucred, td);
1347 if (error)
1348 return (error);
1349
1350 /*
1351 * Check number of open-for-writes on the file and deny execution
1352 * if there are any.
1353 */
1354 if (vp->v_writecount)
1355 return (ETXTBSY);
1356
1357 /*
1358 * Call filesystem specific open routine (which does nothing in the
1359 * general case).
1360 */
1361 error = VOP_OPEN(vp, FREAD, td->td_ucred, td, NULL);
1362 if (error == 0)
1363 imgp->opened = 1;
1364 return (error);
1365}
1366
1367/*
1368 * Exec handler registration
1369 */
1370int
1371exec_register(execsw_arg)
1372 const struct execsw *execsw_arg;
1373{
1374 const struct execsw **es, **xs, **newexecsw;
1375 int count = 2; /* New slot and trailing NULL */
1376
1377 if (execsw)
1378 for (es = execsw; *es; es++)
1379 count++;
1380 newexecsw = malloc(count * sizeof(*es), M_TEMP, M_WAITOK);
1381 if (newexecsw == NULL)
1382 return (ENOMEM);
1383 xs = newexecsw;
1384 if (execsw)
1385 for (es = execsw; *es; es++)
1386 *xs++ = *es;
1387 *xs++ = execsw_arg;
1388 *xs = NULL;
1389 if (execsw)
1390 free(execsw, M_TEMP);
1391 execsw = newexecsw;
1392 return (0);
1393}
1394
1395int
1396exec_unregister(execsw_arg)
1397 const struct execsw *execsw_arg;
1398{
1399 const struct execsw **es, **xs, **newexecsw;
1400 int count = 1;
1401
1402 if (execsw == NULL)
1403 panic("unregister with no handlers left?\n");
1404
1405 for (es = execsw; *es; es++) {
1406 if (*es == execsw_arg)
1407 break;
1408 }
1409 if (*es == NULL)
1410 return (ENOENT);
1411 for (es = execsw; *es; es++)
1412 if (*es != execsw_arg)
1413 count++;
1414 newexecsw = malloc(count * sizeof(*es), M_TEMP, M_WAITOK);
1415 if (newexecsw == NULL)
1416 return (ENOMEM);
1417 xs = newexecsw;
1418 for (es = execsw; *es; es++)
1419 if (*es != execsw_arg)
1420 *xs++ = *es;
1421 *xs = NULL;
1422 if (execsw)
1423 free(execsw, M_TEMP);
1424 execsw = newexecsw;
1425 return (0);
1426}
| 806
807 vfs_mark_atime(imgp->vp, td->td_ucred);
808
809 SDT_PROBE(proc, kernel, , exec_success, args->fname, 0, 0, 0, 0);
810
811done1:
812 /*
813 * Free any resources malloc'd earlier that we didn't use.
814 */
815 uifree(euip);
816 if (newcred == NULL)
817 crfree(oldcred);
818 else
819 crfree(newcred);
820 VOP_UNLOCK(imgp->vp, 0);
821
822 /*
823 * Handle deferred decrement of ref counts.
824 */
825 if (textvp != NULL) {
826 int tvfslocked;
827
828 tvfslocked = VFS_LOCK_GIANT(textvp->v_mount);
829 vrele(textvp);
830 VFS_UNLOCK_GIANT(tvfslocked);
831 }
832 if (binvp && error != 0)
833 vrele(binvp);
834#ifdef KTRACE
835 if (tracevp != NULL) {
836 int tvfslocked;
837
838 tvfslocked = VFS_LOCK_GIANT(tracevp->v_mount);
839 vrele(tracevp);
840 VFS_UNLOCK_GIANT(tvfslocked);
841 }
842 if (tracecred != NULL)
843 crfree(tracecred);
844#endif
845 vn_lock(imgp->vp, LK_EXCLUSIVE | LK_RETRY);
846 pargs_drop(oldargs);
847 pargs_drop(newargs);
848 if (oldsigacts != NULL)
849 sigacts_free(oldsigacts);
850
851exec_fail_dealloc:
852
853 /*
854 * free various allocated resources
855 */
856 if (imgp->firstpage != NULL)
857 exec_unmap_first_page(imgp);
858
859 if (imgp->vp != NULL) {
860 if (args->fname)
861 NDFREE(&nd, NDF_ONLY_PNBUF);
862 if (imgp->opened)
863 VOP_CLOSE(imgp->vp, FREAD, td->td_ucred, td);
864 vput(imgp->vp);
865 }
866
867 if (imgp->object != NULL)
868 vm_object_deallocate(imgp->object);
869
870 free(imgp->freepath, M_TEMP);
871
872 if (error == 0) {
873 /*
874 * Stop the process here if its stop event mask has
875 * the S_EXEC bit set.
876 */
877 STOPEVENT(p, S_EXEC, 0);
878 goto done2;
879 }
880
881exec_fail:
882 /* we're done here, clear P_INEXEC */
883 PROC_LOCK(p);
884 p->p_flag &= ~P_INEXEC;
885 PROC_UNLOCK(p);
886
887 SDT_PROBE(proc, kernel, , exec_failure, error, 0, 0, 0, 0);
888
889done2:
890#ifdef MAC
891 mac_execve_exit(imgp);
892 mac_execve_interpreter_exit(interpvplabel);
893#endif
894 VFS_UNLOCK_GIANT(vfslocked);
895 exec_free_args(args);
896
897 if (error && imgp->vmspace_destroyed) {
898 /* sorry, no more process anymore. exit gracefully */
899 exit1(td, W_EXITCODE(0, SIGABRT));
900 /* NOT REACHED */
901 }
902 return (error);
903}
904
905int
906exec_map_first_page(imgp)
907 struct image_params *imgp;
908{
909 int rv, i;
910 int initial_pagein;
911 vm_page_t ma[VM_INITIAL_PAGEIN];
912 vm_object_t object;
913
914 if (imgp->firstpage != NULL)
915 exec_unmap_first_page(imgp);
916
917 object = imgp->vp->v_object;
918 if (object == NULL)
919 return (EACCES);
920 VM_OBJECT_LOCK(object);
921#if VM_NRESERVLEVEL > 0
922 if ((object->flags & OBJ_COLORED) == 0) {
923 object->flags |= OBJ_COLORED;
924 object->pg_color = 0;
925 }
926#endif
927 ma[0] = vm_page_grab(object, 0, VM_ALLOC_NORMAL | VM_ALLOC_RETRY);
928 if (ma[0]->valid != VM_PAGE_BITS_ALL) {
929 initial_pagein = VM_INITIAL_PAGEIN;
930 if (initial_pagein > object->size)
931 initial_pagein = object->size;
932 for (i = 1; i < initial_pagein; i++) {
933 if ((ma[i] = vm_page_lookup(object, i)) != NULL) {
934 if (ma[i]->valid)
935 break;
936 if ((ma[i]->oflags & VPO_BUSY) || ma[i]->busy)
937 break;
938 vm_page_busy(ma[i]);
939 } else {
940 ma[i] = vm_page_alloc(object, i,
941 VM_ALLOC_NORMAL | VM_ALLOC_IFNOTCACHED);
942 if (ma[i] == NULL)
943 break;
944 }
945 }
946 initial_pagein = i;
947 rv = vm_pager_get_pages(object, ma, initial_pagein, 0);
948 ma[0] = vm_page_lookup(object, 0);
949 if ((rv != VM_PAGER_OK) || (ma[0] == NULL)) {
950 if (ma[0]) {
951 vm_page_lock_queues();
952 vm_page_free(ma[0]);
953 vm_page_unlock_queues();
954 }
955 VM_OBJECT_UNLOCK(object);
956 return (EIO);
957 }
958 }
959 vm_page_lock_queues();
960 vm_page_hold(ma[0]);
961 vm_page_unlock_queues();
962 vm_page_wakeup(ma[0]);
963 VM_OBJECT_UNLOCK(object);
964
965 imgp->firstpage = sf_buf_alloc(ma[0], 0);
966 imgp->image_header = (char *)sf_buf_kva(imgp->firstpage);
967
968 return (0);
969}
970
971void
972exec_unmap_first_page(imgp)
973 struct image_params *imgp;
974{
975 vm_page_t m;
976
977 if (imgp->firstpage != NULL) {
978 m = sf_buf_page(imgp->firstpage);
979 sf_buf_free(imgp->firstpage);
980 imgp->firstpage = NULL;
981 vm_page_lock_queues();
982 vm_page_unhold(m);
983 vm_page_unlock_queues();
984 }
985}
986
987/*
988 * Destroy old address space, and allocate a new stack
989 * The new stack is only SGROWSIZ large because it is grown
990 * automatically in trap.c.
991 */
992int
993exec_new_vmspace(imgp, sv)
994 struct image_params *imgp;
995 struct sysentvec *sv;
996{
997 int error;
998 struct proc *p = imgp->proc;
999 struct vmspace *vmspace = p->p_vmspace;
1000 vm_offset_t sv_minuser, stack_addr;
1001 vm_map_t map;
1002 u_long ssiz;
1003
1004 imgp->vmspace_destroyed = 1;
1005 imgp->sysent = sv;
1006
1007 /* May be called with Giant held */
1008 EVENTHANDLER_INVOKE(process_exec, p, imgp);
1009
1010 /*
1011 * Blow away entire process VM, if address space not shared,
1012 * otherwise, create a new VM space so that other threads are
1013 * not disrupted
1014 */
1015 map = &vmspace->vm_map;
1016 if (map_at_zero)
1017 sv_minuser = sv->sv_minuser;
1018 else
1019 sv_minuser = MAX(sv->sv_minuser, PAGE_SIZE);
1020 if (vmspace->vm_refcnt == 1 && vm_map_min(map) == sv_minuser &&
1021 vm_map_max(map) == sv->sv_maxuser) {
1022 shmexit(vmspace);
1023 pmap_remove_pages(vmspace_pmap(vmspace));
1024 vm_map_remove(map, vm_map_min(map), vm_map_max(map));
1025 } else {
1026 error = vmspace_exec(p, sv_minuser, sv->sv_maxuser);
1027 if (error)
1028 return (error);
1029 vmspace = p->p_vmspace;
1030 map = &vmspace->vm_map;
1031 }
1032
1033 /* Allocate a new stack */
1034 if (sv->sv_maxssiz != NULL)
1035 ssiz = *sv->sv_maxssiz;
1036 else
1037 ssiz = maxssiz;
1038 stack_addr = sv->sv_usrstack - ssiz;
1039 error = vm_map_stack(map, stack_addr, (vm_size_t)ssiz,
1040 sv->sv_stackprot, VM_PROT_ALL, MAP_STACK_GROWS_DOWN);
1041 if (error)
1042 return (error);
1043
1044#ifdef __ia64__
1045 /* Allocate a new register stack */
1046 stack_addr = IA64_BACKINGSTORE;
1047 error = vm_map_stack(map, stack_addr, (vm_size_t)ssiz,
1048 sv->sv_stackprot, VM_PROT_ALL, MAP_STACK_GROWS_UP);
1049 if (error)
1050 return (error);
1051#endif
1052
1053 /* vm_ssize and vm_maxsaddr are somewhat antiquated concepts in the
1054 * VM_STACK case, but they are still used to monitor the size of the
1055 * process stack so we can check the stack rlimit.
1056 */
1057 vmspace->vm_ssize = sgrowsiz >> PAGE_SHIFT;
1058 vmspace->vm_maxsaddr = (char *)sv->sv_usrstack - ssiz;
1059
1060 return (0);
1061}
1062
1063/*
1064 * Copy out argument and environment strings from the old process address
1065 * space into the temporary string buffer.
1066 */
1067int
1068exec_copyin_args(struct image_args *args, char *fname,
1069 enum uio_seg segflg, char **argv, char **envv)
1070{
1071 char *argp, *envp;
1072 int error;
1073 size_t length;
1074
1075 bzero(args, sizeof(*args));
1076 if (argv == NULL)
1077 return (EFAULT);
1078 /*
1079 * Allocate temporary demand zeroed space for argument and
1080 * environment strings:
1081 *
1082 * o ARG_MAX for argument and environment;
1083 * o MAXSHELLCMDLEN for the name of interpreters.
1084 */
1085 args->buf = (char *) kmem_alloc_wait(exec_map,
1086 PATH_MAX + ARG_MAX + MAXSHELLCMDLEN);
1087 if (args->buf == NULL)
1088 return (ENOMEM);
1089 args->begin_argv = args->buf;
1090 args->endp = args->begin_argv;
1091 args->stringspace = ARG_MAX;
1092 /*
1093 * Copy the file name.
1094 */
1095 if (fname != NULL) {
1096 args->fname = args->buf + ARG_MAX;
1097 error = (segflg == UIO_SYSSPACE) ?
1098 copystr(fname, args->fname, PATH_MAX, &length) :
1099 copyinstr(fname, args->fname, PATH_MAX, &length);
1100 if (error != 0)
1101 goto err_exit;
1102 } else
1103 args->fname = NULL;
1104
1105 /*
1106 * extract arguments first
1107 */
1108 while ((argp = (caddr_t) (intptr_t) fuword(argv++))) {
1109 if (argp == (caddr_t) -1) {
1110 error = EFAULT;
1111 goto err_exit;
1112 }
1113 if ((error = copyinstr(argp, args->endp,
1114 args->stringspace, &length))) {
1115 if (error == ENAMETOOLONG)
1116 error = E2BIG;
1117 goto err_exit;
1118 }
1119 args->stringspace -= length;
1120 args->endp += length;
1121 args->argc++;
1122 }
1123
1124 args->begin_envv = args->endp;
1125
1126 /*
1127 * extract environment strings
1128 */
1129 if (envv) {
1130 while ((envp = (caddr_t)(intptr_t)fuword(envv++))) {
1131 if (envp == (caddr_t)-1) {
1132 error = EFAULT;
1133 goto err_exit;
1134 }
1135 if ((error = copyinstr(envp, args->endp,
1136 args->stringspace, &length))) {
1137 if (error == ENAMETOOLONG)
1138 error = E2BIG;
1139 goto err_exit;
1140 }
1141 args->stringspace -= length;
1142 args->endp += length;
1143 args->envc++;
1144 }
1145 }
1146
1147 return (0);
1148
1149err_exit:
1150 exec_free_args(args);
1151 return (error);
1152}
1153
1154static void
1155exec_free_args(struct image_args *args)
1156{
1157
1158 if (args->buf) {
1159 kmem_free_wakeup(exec_map, (vm_offset_t)args->buf,
1160 PATH_MAX + ARG_MAX + MAXSHELLCMDLEN);
1161 args->buf = NULL;
1162 }
1163}
1164
1165/*
1166 * Copy strings out to the new process address space, constructing new arg
1167 * and env vector tables. Return a pointer to the base so that it can be used
1168 * as the initial stack pointer.
1169 */
1170register_t *
1171exec_copyout_strings(imgp)
1172 struct image_params *imgp;
1173{
1174 int argc, envc;
1175 char **vectp;
1176 char *stringp, *destp;
1177 register_t *stack_base;
1178 struct ps_strings *arginfo;
1179 struct proc *p;
1180 size_t execpath_len;
1181 int szsigcode;
1182
1183 /*
1184 * Calculate string base and vector table pointers.
1185 * Also deal with signal trampoline code for this exec type.
1186 */
1187 if (imgp->execpath != NULL && imgp->auxargs != NULL)
1188 execpath_len = strlen(imgp->execpath) + 1;
1189 else
1190 execpath_len = 0;
1191 p = imgp->proc;
1192 szsigcode = 0;
1193 arginfo = (struct ps_strings *)p->p_sysent->sv_psstrings;
1194 if (p->p_sysent->sv_szsigcode != NULL)
1195 szsigcode = *(p->p_sysent->sv_szsigcode);
1196 destp = (caddr_t)arginfo - szsigcode - SPARE_USRSPACE -
1197 roundup(execpath_len, sizeof(char *)) -
1198 roundup((ARG_MAX - imgp->args->stringspace), sizeof(char *));
1199
1200 /*
1201 * install sigcode
1202 */
1203 if (szsigcode)
1204 copyout(p->p_sysent->sv_sigcode, ((caddr_t)arginfo -
1205 szsigcode), szsigcode);
1206
1207 /*
1208 * Copy the image path for the rtld.
1209 */
1210 if (execpath_len != 0) {
1211 imgp->execpathp = (uintptr_t)arginfo - szsigcode - execpath_len;
1212 copyout(imgp->execpath, (void *)imgp->execpathp,
1213 execpath_len);
1214 }
1215
1216 /*
1217 * If we have a valid auxargs ptr, prepare some room
1218 * on the stack.
1219 */
1220 if (imgp->auxargs) {
1221 /*
1222 * 'AT_COUNT*2' is size for the ELF Auxargs data. This is for
1223 * lower compatibility.
1224 */
1225 imgp->auxarg_size = (imgp->auxarg_size) ? imgp->auxarg_size :
1226 (AT_COUNT * 2);
1227 /*
1228 * The '+ 2' is for the null pointers at the end of each of
1229 * the arg and env vector sets,and imgp->auxarg_size is room
1230 * for argument of Runtime loader.
1231 */
1232 vectp = (char **)(destp - (imgp->args->argc +
1233 imgp->args->envc + 2 + imgp->auxarg_size + execpath_len) *
1234 sizeof(char *));
1235 } else {
1236 /*
1237 * The '+ 2' is for the null pointers at the end of each of
1238 * the arg and env vector sets
1239 */
1240 vectp = (char **)(destp - (imgp->args->argc + imgp->args->envc + 2) *
1241 sizeof(char *));
1242 }
1243
1244 /*
1245 * vectp also becomes our initial stack base
1246 */
1247 stack_base = (register_t *)vectp;
1248
1249 stringp = imgp->args->begin_argv;
1250 argc = imgp->args->argc;
1251 envc = imgp->args->envc;
1252
1253 /*
1254 * Copy out strings - arguments and environment.
1255 */
1256 copyout(stringp, destp, ARG_MAX - imgp->args->stringspace);
1257
1258 /*
1259 * Fill in "ps_strings" struct for ps, w, etc.
1260 */
1261 suword(&arginfo->ps_argvstr, (long)(intptr_t)vectp);
1262 suword32(&arginfo->ps_nargvstr, argc);
1263
1264 /*
1265 * Fill in argument portion of vector table.
1266 */
1267 for (; argc > 0; --argc) {
1268 suword(vectp++, (long)(intptr_t)destp);
1269 while (*stringp++ != 0)
1270 destp++;
1271 destp++;
1272 }
1273
1274 /* a null vector table pointer separates the argp's from the envp's */
1275 suword(vectp++, 0);
1276
1277 suword(&arginfo->ps_envstr, (long)(intptr_t)vectp);
1278 suword32(&arginfo->ps_nenvstr, envc);
1279
1280 /*
1281 * Fill in environment portion of vector table.
1282 */
1283 for (; envc > 0; --envc) {
1284 suword(vectp++, (long)(intptr_t)destp);
1285 while (*stringp++ != 0)
1286 destp++;
1287 destp++;
1288 }
1289
1290 /* end of vector table is a null pointer */
1291 suword(vectp, 0);
1292
1293 return (stack_base);
1294}
1295
1296/*
1297 * Check permissions of file to execute.
1298 * Called with imgp->vp locked.
1299 * Return 0 for success or error code on failure.
1300 */
1301int
1302exec_check_permissions(imgp)
1303 struct image_params *imgp;
1304{
1305 struct vnode *vp = imgp->vp;
1306 struct vattr *attr = imgp->attr;
1307 struct thread *td;
1308 int error;
1309
1310 td = curthread;
1311
1312 /* Get file attributes */
1313 error = VOP_GETATTR(vp, attr, td->td_ucred);
1314 if (error)
1315 return (error);
1316
1317#ifdef MAC
1318 error = mac_vnode_check_exec(td->td_ucred, imgp->vp, imgp);
1319 if (error)
1320 return (error);
1321#endif
1322
1323 /*
1324 * 1) Check if file execution is disabled for the filesystem that this
1325 * file resides on.
1326 * 2) Insure that at least one execute bit is on - otherwise root
1327 * will always succeed, and we don't want to happen unless the
1328 * file really is executable.
1329 * 3) Insure that the file is a regular file.
1330 */
1331 if ((vp->v_mount->mnt_flag & MNT_NOEXEC) ||
1332 ((attr->va_mode & 0111) == 0) ||
1333 (attr->va_type != VREG))
1334 return (EACCES);
1335
1336 /*
1337 * Zero length files can't be exec'd
1338 */
1339 if (attr->va_size == 0)
1340 return (ENOEXEC);
1341
1342 /*
1343 * Check for execute permission to file based on current credentials.
1344 */
1345 error = VOP_ACCESS(vp, VEXEC, td->td_ucred, td);
1346 if (error)
1347 return (error);
1348
1349 /*
1350 * Check number of open-for-writes on the file and deny execution
1351 * if there are any.
1352 */
1353 if (vp->v_writecount)
1354 return (ETXTBSY);
1355
1356 /*
1357 * Call filesystem specific open routine (which does nothing in the
1358 * general case).
1359 */
1360 error = VOP_OPEN(vp, FREAD, td->td_ucred, td, NULL);
1361 if (error == 0)
1362 imgp->opened = 1;
1363 return (error);
1364}
1365
1366/*
1367 * Exec handler registration
1368 */
1369int
1370exec_register(execsw_arg)
1371 const struct execsw *execsw_arg;
1372{
1373 const struct execsw **es, **xs, **newexecsw;
1374 int count = 2; /* New slot and trailing NULL */
1375
1376 if (execsw)
1377 for (es = execsw; *es; es++)
1378 count++;
1379 newexecsw = malloc(count * sizeof(*es), M_TEMP, M_WAITOK);
1380 if (newexecsw == NULL)
1381 return (ENOMEM);
1382 xs = newexecsw;
1383 if (execsw)
1384 for (es = execsw; *es; es++)
1385 *xs++ = *es;
1386 *xs++ = execsw_arg;
1387 *xs = NULL;
1388 if (execsw)
1389 free(execsw, M_TEMP);
1390 execsw = newexecsw;
1391 return (0);
1392}
1393
1394int
1395exec_unregister(execsw_arg)
1396 const struct execsw *execsw_arg;
1397{
1398 const struct execsw **es, **xs, **newexecsw;
1399 int count = 1;
1400
1401 if (execsw == NULL)
1402 panic("unregister with no handlers left?\n");
1403
1404 for (es = execsw; *es; es++) {
1405 if (*es == execsw_arg)
1406 break;
1407 }
1408 if (*es == NULL)
1409 return (ENOENT);
1410 for (es = execsw; *es; es++)
1411 if (*es != execsw_arg)
1412 count++;
1413 newexecsw = malloc(count * sizeof(*es), M_TEMP, M_WAITOK);
1414 if (newexecsw == NULL)
1415 return (ENOMEM);
1416 xs = newexecsw;
1417 for (es = execsw; *es; es++)
1418 if (*es != execsw_arg)
1419 *xs++ = *es;
1420 *xs = NULL;
1421 if (execsw)
1422 free(execsw, M_TEMP);
1423 execsw = newexecsw;
1424 return (0);
1425}
|