2 * Copyright (c) 2013-16, Stacey D. Son
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 <sys/param.h>
31 #include <sys/ctype.h>
33 #include <sys/fcntl.h>
34 #include <sys/imgact.h>
35 #include <sys/imgact_binmisc.h>
36 #include <sys/kernel.h>
38 #include <sys/malloc.h>
39 #include <sys/mutex.h>
40 #include <sys/namei.h>
42 #include <sys/sysctl.h>
44 #include <sys/vnode.h>
46 #include <machine/atomic.h>
49 * Miscellaneous binary interpreter image activator.
51 * If the given target executable's header matches 'xbe_magic' field in the
52 * 'interpreter_list' then it will use the user-level interpreter specified in
53 * the 'xbe_interpreter' field to execute the binary. The 'xbe_magic' field may
54 * be adjusted to a given offset using the value in the 'xbe_moffset' field
55 * and bits of the header may be masked using the 'xbe_mask' field. The
56 * 'interpreter_list' entries are managed using sysctl(3) as described in the
57 * <sys/imgact_binmisc.h> file.
61 * Node of the interpreter list.
63 typedef struct imgact_binmisc_entry {
64 SLIST_ENTRY(imgact_binmisc_entry) link;
68 uint8_t *ibe_interpreter;
69 struct vnode *ibe_interpreter_vnode;
70 ssize_t ibe_interp_offset;
71 uint32_t ibe_interp_argcnt;
72 uint32_t ibe_interp_length;
73 uint32_t ibe_argv0_cnt;
77 } imgact_binmisc_entry_t;
82 #define IBC_ADD 1 /* Add given entry. */
83 #define IBC_REMOVE 2 /* Remove entry for a given name. */
84 #define IBC_DISABLE 3 /* Disable entry for a given name. */
85 #define IBC_ENABLE 4 /* Enable entry for a given name. */
86 #define IBC_LOOKUP 5 /* Lookup and return entry for given name. */
87 #define IBC_LIST 6 /* Get a snapshot of the interpretor list. */
90 * Interpreter string macros.
92 * They all start with '#' followed by a single letter:
94 #define ISM_POUND '#' /* "##" is the escape sequence for single #. */
95 #define ISM_OLD_ARGV0 'a' /* "#a" is replaced with the old argv0. */
97 MALLOC_DEFINE(M_BINMISC, KMOD_NAME, "misc binary image activator");
99 /* The interpreter list. */
100 static SLIST_HEAD(, imgact_binmisc_entry) interpreter_list =
101 SLIST_HEAD_INITIALIZER(interpreter_list);
103 static int interp_list_entry_count;
105 static struct sx interp_list_sx;
107 #define INTERP_LIST_WLOCK() sx_xlock(&interp_list_sx)
108 #define INTERP_LIST_RLOCK() sx_slock(&interp_list_sx)
109 #define INTERP_LIST_WUNLOCK() sx_xunlock(&interp_list_sx)
110 #define INTERP_LIST_RUNLOCK() sx_sunlock(&interp_list_sx)
112 #define INTERP_LIST_LOCK_INIT() sx_init(&interp_list_sx, KMOD_NAME)
113 #define INTERP_LIST_LOCK_DESTROY() sx_destroy(&interp_list_sx)
115 #define INTERP_LIST_ASSERT_LOCKED() sx_assert(&interp_list_sx, SA_LOCKED)
118 * Populate the entry with the information about the interpreter.
121 imgact_binmisc_populate_interp(char *str, imgact_binmisc_entry_t *ibe, int flags)
123 uint32_t len = 0, argc = 1;
124 char t[IBE_INTERP_LEN_MAX];
127 memset(t, 0, sizeof(t));
130 * Normalize interpreter string. Replace white space between args with
134 while (*sp != '\0') {
135 if (*sp == ' ' || *sp == '\t') {
136 if (++len >= IBE_INTERP_LEN_MAX)
140 while (*sp == ' ' || *sp == '\t')
151 ibe->ibe_interpreter = malloc(len, M_BINMISC, M_WAITOK|M_ZERO);
153 /* Populate all the ibe fields for the interpreter. */
154 memcpy(ibe->ibe_interpreter, t, len);
155 ibe->ibe_interp_argcnt = argc;
156 ibe->ibe_interp_length = len;
158 ibe->ibe_interpreter_vnode = NULL;
159 if (flags & IBF_PRE_OPEN) {
164 while (*tp != '\0' && *tp != ' ') {
168 NDINIT(&nd, LOOKUP, FOLLOW | ISOPEN, UIO_SYSSPACE, t, curthread);
171 * If there is an error, just stop now and fall back
172 * to the non pre-open case where we lookup during
179 ibe->ibe_interpreter_vnode = nd.ni_vp;
184 * Allocate memory and populate a new entry for the interpreter table.
186 static imgact_binmisc_entry_t *
187 imgact_binmisc_new_entry(ximgact_binmisc_entry_t *xbe, ssize_t interp_offset,
190 imgact_binmisc_entry_t *ibe = NULL;
191 size_t namesz = min(strlen(xbe->xbe_name) + 1, IBE_NAME_MAX);
193 ibe = malloc(sizeof(*ibe), M_BINMISC, M_WAITOK|M_ZERO);
195 ibe->ibe_name = malloc(namesz, M_BINMISC, M_WAITOK|M_ZERO);
196 strlcpy(ibe->ibe_name, xbe->xbe_name, namesz);
198 imgact_binmisc_populate_interp(xbe->xbe_interpreter, ibe, xbe->xbe_flags);
200 ibe->ibe_magic = malloc(xbe->xbe_msize, M_BINMISC, M_WAITOK|M_ZERO);
201 memcpy(ibe->ibe_magic, xbe->xbe_magic, xbe->xbe_msize);
203 ibe->ibe_mask = malloc(xbe->xbe_msize, M_BINMISC, M_WAITOK|M_ZERO);
204 memcpy(ibe->ibe_mask, xbe->xbe_mask, xbe->xbe_msize);
206 ibe->ibe_moffset = xbe->xbe_moffset;
207 ibe->ibe_msize = xbe->xbe_msize;
208 ibe->ibe_flags = xbe->xbe_flags;
209 ibe->ibe_interp_offset = interp_offset;
210 ibe->ibe_argv0_cnt = argv0_cnt;
215 * Free the allocated memory for a given list item.
218 imgact_binmisc_destroy_entry(imgact_binmisc_entry_t *ibe)
223 free(ibe->ibe_magic, M_BINMISC);
225 free(ibe->ibe_mask, M_BINMISC);
226 if (ibe->ibe_interpreter)
227 free(ibe->ibe_interpreter, M_BINMISC);
229 free(ibe->ibe_name, M_BINMISC);
230 if (ibe->ibe_interpreter_vnode)
231 vrele(ibe->ibe_interpreter_vnode);
233 free(ibe, M_BINMISC);
237 * Find the interpreter in the list by the given name. Return NULL if not
240 static imgact_binmisc_entry_t *
241 imgact_binmisc_find_entry(char *name)
243 imgact_binmisc_entry_t *ibe;
245 INTERP_LIST_ASSERT_LOCKED();
247 SLIST_FOREACH(ibe, &interpreter_list, link) {
248 if (strncmp(name, ibe->ibe_name, IBE_NAME_MAX) == 0)
256 * Add the given interpreter if it doesn't already exist. Return EEXIST
257 * if the name already exist in the interpreter list.
260 imgact_binmisc_add_entry(ximgact_binmisc_entry_t *xbe)
262 imgact_binmisc_entry_t *ibe;
264 ssize_t interp_offset;
267 if (xbe->xbe_msize > IBE_MAGIC_MAX)
269 if (xbe->xbe_moffset + xbe->xbe_msize > IBE_MATCH_MAX)
272 for(cnt = 0, p = xbe->xbe_name; *p != 0; cnt++, p++)
273 if (cnt >= IBE_NAME_MAX || !isascii((int)*p))
276 for(cnt = 0, p = xbe->xbe_interpreter; *p != 0; cnt++, p++)
277 if (cnt >= IBE_INTERP_LEN_MAX || !isascii((int)*p))
280 /* Make sure we don't have any invalid #'s. */
281 p = xbe->xbe_interpreter;
284 while ((p = strchr(p, '#')) != NULL) {
299 /* Anything besides the above is invalid. */
305 * Preallocate a new entry. We do this without holding the
306 * lock to avoid lock-order problems if IBF_PRE_OPEN is
309 ibe = imgact_binmisc_new_entry(xbe, interp_offset, argv0_cnt);
312 if (imgact_binmisc_find_entry(xbe->xbe_name) != NULL) {
313 INTERP_LIST_WUNLOCK();
314 imgact_binmisc_destroy_entry(ibe);
318 SLIST_INSERT_HEAD(&interpreter_list, ibe, link);
319 interp_list_entry_count++;
320 INTERP_LIST_WUNLOCK();
326 * Remove the interpreter in the list with the given name. Return ENOENT
330 imgact_binmisc_remove_entry(char *name)
332 imgact_binmisc_entry_t *ibe;
335 if ((ibe = imgact_binmisc_find_entry(name)) == NULL) {
336 INTERP_LIST_WUNLOCK();
339 SLIST_REMOVE(&interpreter_list, ibe, imgact_binmisc_entry, link);
340 interp_list_entry_count--;
341 INTERP_LIST_WUNLOCK();
343 imgact_binmisc_destroy_entry(ibe);
349 * Disable the interpreter in the list with the given name. Return ENOENT
353 imgact_binmisc_disable_entry(char *name)
355 imgact_binmisc_entry_t *ibe;
358 if ((ibe = imgact_binmisc_find_entry(name)) == NULL) {
359 INTERP_LIST_WUNLOCK();
363 ibe->ibe_flags &= ~IBF_ENABLED;
364 INTERP_LIST_WUNLOCK();
370 * Enable the interpreter in the list with the given name. Return ENOENT
374 imgact_binmisc_enable_entry(char *name)
376 imgact_binmisc_entry_t *ibe;
379 if ((ibe = imgact_binmisc_find_entry(name)) == NULL) {
380 INTERP_LIST_WUNLOCK();
384 ibe->ibe_flags |= IBF_ENABLED;
385 INTERP_LIST_WUNLOCK();
391 imgact_binmisc_populate_xbe(ximgact_binmisc_entry_t *xbe,
392 imgact_binmisc_entry_t *ibe)
396 INTERP_LIST_ASSERT_LOCKED();
397 memset(xbe, 0, sizeof(*xbe));
398 strlcpy(xbe->xbe_name, ibe->ibe_name, IBE_NAME_MAX);
400 /* Copy interpreter string. Replace NULL breaks with space. */
401 memcpy(xbe->xbe_interpreter, ibe->ibe_interpreter,
402 ibe->ibe_interp_length);
403 for(i = 0; i < (ibe->ibe_interp_length - 1); i++)
404 if (xbe->xbe_interpreter[i] == '\0')
405 xbe->xbe_interpreter[i] = ' ';
407 memcpy(xbe->xbe_magic, ibe->ibe_magic, ibe->ibe_msize);
408 memcpy(xbe->xbe_mask, ibe->ibe_mask, ibe->ibe_msize);
409 xbe->xbe_version = IBE_VERSION;
410 xbe->xbe_flags = ibe->ibe_flags;
411 xbe->xbe_moffset = ibe->ibe_moffset;
412 xbe->xbe_msize = ibe->ibe_msize;
418 * Retrieve the interpreter with the give name and populate the
419 * ximgact_binmisc_entry structure. Return ENOENT if not found.
422 imgact_binmisc_lookup_entry(char *name, ximgact_binmisc_entry_t *xbe)
424 imgact_binmisc_entry_t *ibe;
428 if ((ibe = imgact_binmisc_find_entry(name)) == NULL) {
429 INTERP_LIST_RUNLOCK();
433 error = imgact_binmisc_populate_xbe(xbe, ibe);
434 INTERP_LIST_RUNLOCK();
440 * Get a snapshot of all the interpreter entries in the list.
443 imgact_binmisc_get_all_entries(struct sysctl_req *req)
445 ximgact_binmisc_entry_t *xbe, *xbep;
446 imgact_binmisc_entry_t *ibe;
447 int error = 0, count;
450 count = interp_list_entry_count;
451 xbe = malloc(sizeof(*xbe) * count, M_BINMISC, M_WAITOK|M_ZERO);
454 SLIST_FOREACH(ibe, &interpreter_list, link) {
455 error = imgact_binmisc_populate_xbe(xbep++, ibe);
459 INTERP_LIST_RUNLOCK();
462 error = SYSCTL_OUT(req, xbe, sizeof(*xbe) * count);
464 free(xbe, M_BINMISC);
469 * sysctl() handler for munipulating interpretor table.
470 * Not MP safe (locked by sysctl).
473 sysctl_kern_binmisc(SYSCTL_HANDLER_ARGS)
475 ximgact_binmisc_entry_t xbe;
480 /* Add an entry. Limited to IBE_MAX_ENTRIES. */
481 error = SYSCTL_IN(req, &xbe, sizeof(xbe));
484 if (IBE_VERSION != xbe.xbe_version)
486 if ((xbe.xbe_flags & ~IBF_VALID_UFLAGS) != 0)
488 if (interp_list_entry_count == IBE_MAX_ENTRIES)
490 error = imgact_binmisc_add_entry(&xbe);
494 /* Remove an entry. */
495 error = SYSCTL_IN(req, &xbe, sizeof(xbe));
498 if (IBE_VERSION != xbe.xbe_version)
500 error = imgact_binmisc_remove_entry(xbe.xbe_name);
504 /* Disable an entry. */
505 error = SYSCTL_IN(req, &xbe, sizeof(xbe));
508 if (IBE_VERSION != xbe.xbe_version)
510 error = imgact_binmisc_disable_entry(xbe.xbe_name);
514 /* Enable an entry. */
515 error = SYSCTL_IN(req, &xbe, sizeof(xbe));
518 if (IBE_VERSION != xbe.xbe_version)
520 error = imgact_binmisc_enable_entry(xbe.xbe_name);
524 /* Lookup an entry. */
525 error = SYSCTL_IN(req, &xbe, sizeof(xbe));
528 if (IBE_VERSION != xbe.xbe_version)
530 error = imgact_binmisc_lookup_entry(xbe.xbe_name, &xbe);
532 error = SYSCTL_OUT(req, &xbe, sizeof(xbe));
536 /* Return a snapshot of the interpretor list. */
539 /* No pointer then just return the list size. */
540 error = SYSCTL_OUT(req, 0, interp_list_entry_count *
541 sizeof(ximgact_binmisc_entry_t));
547 error = imgact_binmisc_get_all_entries(req);
557 SYSCTL_NODE(_kern, OID_AUTO, binmisc, CTLFLAG_RW | CTLFLAG_MPSAFE, 0,
558 "Image activator for miscellaneous binaries");
560 SYSCTL_PROC(_kern_binmisc, OID_AUTO, add,
561 CTLFLAG_MPSAFE|CTLTYPE_STRUCT|CTLFLAG_WR, NULL, IBC_ADD,
562 sysctl_kern_binmisc, "S,ximgact_binmisc_entry",
563 "Add an activator entry");
565 SYSCTL_PROC(_kern_binmisc, OID_AUTO, remove,
566 CTLFLAG_MPSAFE|CTLTYPE_STRUCT|CTLFLAG_WR, NULL, IBC_REMOVE,
567 sysctl_kern_binmisc, "S,ximgact_binmisc_entry",
568 "Remove an activator entry");
570 SYSCTL_PROC(_kern_binmisc, OID_AUTO, disable,
571 CTLFLAG_MPSAFE|CTLTYPE_STRUCT|CTLFLAG_WR, NULL, IBC_DISABLE,
572 sysctl_kern_binmisc, "S,ximgact_binmisc_entry",
573 "Disable an activator entry");
575 SYSCTL_PROC(_kern_binmisc, OID_AUTO, enable,
576 CTLFLAG_MPSAFE|CTLTYPE_STRUCT|CTLFLAG_WR, NULL, IBC_ENABLE,
577 sysctl_kern_binmisc, "S,ximgact_binmisc_entry",
578 "Enable an activator entry");
580 SYSCTL_PROC(_kern_binmisc, OID_AUTO, lookup,
581 CTLFLAG_MPSAFE|CTLTYPE_STRUCT|CTLFLAG_RW|CTLFLAG_ANYBODY, NULL, IBC_LOOKUP,
582 sysctl_kern_binmisc, "S,ximgact_binmisc_entry",
583 "Lookup an activator entry");
585 SYSCTL_PROC(_kern_binmisc, OID_AUTO, list,
586 CTLFLAG_MPSAFE|CTLTYPE_STRUCT|CTLFLAG_RD|CTLFLAG_ANYBODY, NULL, IBC_LIST,
587 sysctl_kern_binmisc, "S,ximgact_binmisc_entry",
588 "Get snapshot of all the activator entries");
590 static imgact_binmisc_entry_t *
591 imgact_binmisc_find_interpreter(const char *image_header)
593 imgact_binmisc_entry_t *ibe;
598 INTERP_LIST_ASSERT_LOCKED();
600 SLIST_FOREACH(ibe, &interpreter_list, link) {
601 if (!(IBF_ENABLED & ibe->ibe_flags))
604 p = image_header + ibe->ibe_moffset;
606 if (IBF_USE_MASK & ibe->ibe_flags) {
607 /* Compare using mask. */
608 for (i = 0; i < sz; i++)
609 if ((*p++ ^ ibe->ibe_magic[i]) &
613 for (i = 0; i < sz; i++)
614 if (*p++ ^ ibe->ibe_magic[i])
617 if (i == ibe->ibe_msize)
624 imgact_binmisc_exec(struct image_params *imgp)
626 const char *image_header = imgp->image_header;
627 const char *fname = NULL;
632 size_t namelen, offset;
633 imgact_binmisc_entry_t *ibe;
639 /* Do we have an interpreter for the given image header? */
641 if ((ibe = imgact_binmisc_find_interpreter(image_header)) == NULL) {
646 /* No interpreter nesting allowed. */
647 if (imgp->interpreted & IMGACT_BINMISC) {
652 imgp->interpreted |= IMGACT_BINMISC;
655 * Don't bother with the overhead of putting fname together if we're not
658 if (ibe->ibe_argv0_cnt != 0) {
659 if (imgp->args->fname != NULL) {
660 fname = imgp->args->fname;
662 /* Use the fdescfs(5) path for fexecve(2). */
663 sname = sbuf_new_auto();
664 sbuf_printf(sname, "/dev/fd/%d", imgp->args->fd);
666 fname = sbuf_data(sname);
669 namelen = strlen(fname);
673 * We need to "push" the interpreter in the arg[] list. To do this,
674 * we first shift all the other values in the `begin_argv' area to
675 * provide the exact amount of room for the values added. Set up
676 * `offset' as the number of bytes to be added to the `begin_argv'
677 * area. ibe_interp_offset is the fixed offset from macros present in
678 * the interpreter string.
680 offset = ibe->ibe_interp_length + ibe->ibe_interp_offset;
682 /* Variable offset to be added from macros to the interpreter string. */
683 MPASS(ibe->ibe_argv0_cnt == 0 || namelen > 0);
684 offset += ibe->ibe_argv0_cnt * (namelen - 2);
686 /* Make room for the interpreter */
687 error = exec_args_adjust_args(imgp->args, 0, offset);
692 /* Add the new argument(s) in the count. */
693 imgp->args->argc += ibe->ibe_interp_argcnt;
696 * The original arg[] list has been shifted appropriately. Copy in
697 * the interpreter path.
699 s = ibe->ibe_interpreter;
700 d = imgp->args->begin_argv;
704 /* Handle "#" in interpreter string. */
708 /* "##": Replace with a single '#' */
712 /* "#a": Replace with old arg0 (fname). */
713 MPASS(ibe->ibe_argv0_cnt >= ++argv0_cnt);
714 memcpy(d, fname, namelen);
718 __assert_unreachable();
722 /* Replace space with NUL to separate arguments. */
733 /* Catch ibe->ibe_argv0_cnt counting more #a than we did. */
734 MPASS(ibe->ibe_argv0_cnt == argv0_cnt);
735 imgp->interpreter_name = imgp->args->begin_argv;
736 if (ibe->ibe_interpreter_vnode) {
737 imgp->interpreter_vp = ibe->ibe_interpreter_vnode;
738 vref(imgp->interpreter_vp);
742 INTERP_LIST_RUNLOCK();
749 imgact_binmisc_init(void *arg)
752 INTERP_LIST_LOCK_INIT();
756 imgact_binmisc_fini(void *arg)
758 imgact_binmisc_entry_t *ibe, *ibe_tmp;
760 /* Free all the interpreters. */
762 SLIST_FOREACH_SAFE(ibe, &interpreter_list, link, ibe_tmp) {
763 SLIST_REMOVE(&interpreter_list, ibe, imgact_binmisc_entry,
765 imgact_binmisc_destroy_entry(ibe);
767 INTERP_LIST_WUNLOCK();
769 INTERP_LIST_LOCK_DESTROY();
772 SYSINIT(imgact_binmisc, SI_SUB_EXEC, SI_ORDER_MIDDLE, imgact_binmisc_init,
774 SYSUNINIT(imgact_binmisc, SI_SUB_EXEC, SI_ORDER_MIDDLE, imgact_binmisc_fini,
778 * Tell kern_execve.c about it, with a little help from the linker.
780 static struct execsw imgact_binmisc_execsw = {
781 .ex_imgact = imgact_binmisc_exec,
784 EXEC_SET(imgact_binmisc, imgact_binmisc_execsw);