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/systm.h>
34 #include <sys/sysproto.h>
36 #include <sys/imgact.h>
37 #include <sys/imgact_binmisc.h>
38 #include <sys/kernel.h>
39 #include <sys/libkern.h>
41 #include <sys/malloc.h>
42 #include <sys/mutex.h>
43 #include <sys/sysctl.h>
46 * Miscellaneous binary interpreter image activator.
48 * If the given target executable's header matches 'xbe_magic' field in the
49 * 'interpreter_list' then it will use the user-level interpreter specified in
50 * the 'xbe_interpreter' field to execute the binary. The 'xbe_magic' field may
51 * be adjusted to a given offset using the value in the 'xbe_moffset' field
52 * and bits of the header may be masked using the 'xbe_mask' field. The
53 * 'interpreter_list' entries are managed using sysctl(3) as described in the
54 * <sys/imgact_binmisc.h> file.
58 * Node of the interpreter list.
60 typedef struct imgact_binmisc_entry {
66 uint8_t *ibe_interpreter;
67 uint32_t ibe_interp_argcnt;
68 uint32_t ibe_interp_length;
70 SLIST_ENTRY(imgact_binmisc_entry) link;
71 } imgact_binmisc_entry_t;
76 #define IBC_ADD 1 /* Add given entry. */
77 #define IBC_REMOVE 2 /* Remove entry for a given name. */
78 #define IBC_DISABLE 3 /* Disable entry for a given name. */
79 #define IBC_ENABLE 4 /* Enable entry for a given name. */
80 #define IBC_LOOKUP 5 /* Lookup and return entry for given name. */
81 #define IBC_LIST 6 /* Get a snapshot of the interpretor list. */
84 * Interpreter string macros.
86 * They all start with '#' followed by a single letter:
88 #define ISM_POUND '#' /* "##" is the escape sequence for single #. */
89 #define ISM_OLD_ARGV0 'a' /* "#a" is replaced with the old argv0. */
91 MALLOC_DEFINE(M_BINMISC, KMOD_NAME, "misc binary image activator");
93 /* The interpreter list. */
94 static SLIST_HEAD(, imgact_binmisc_entry) interpreter_list =
95 SLIST_HEAD_INITIALIZER(interpreter_list);
97 static int interp_list_entry_count = 0;
99 static struct mtx interp_list_mtx;
101 int imgact_binmisc_exec(struct image_params *imgp);
105 * Populate the entry with the information about the interpreter.
108 imgact_binmisc_populate_interp(char *str, imgact_binmisc_entry_t *ibe)
110 uint32_t len = 0, argc = 1;
111 char t[IBE_INTERP_LEN_MAX];
117 * Normalize interpreter string. Replace white space between args with
121 while (*sp != '\0') {
122 if (*sp == ' ' || *sp == '\t') {
123 if (++len > IBE_INTERP_LEN_MAX)
127 while (*sp == ' ' || *sp == '\t')
138 ibe->ibe_interpreter = malloc(len, M_BINMISC, M_WAITOK|M_ZERO);
140 /* Populate all the ibe fields for the interpreter. */
141 memcpy(ibe->ibe_interpreter, t, len);
142 ibe->ibe_interp_argcnt = argc;
143 ibe->ibe_interp_length = len;
147 * Allocate memory and populate a new entry for the interpreter table.
149 static imgact_binmisc_entry_t *
150 imgact_binmisc_new_entry(ximgact_binmisc_entry_t *xbe)
152 imgact_binmisc_entry_t *ibe = NULL;
153 size_t namesz = min(strlen(xbe->xbe_name) + 1, IBE_NAME_MAX);
155 mtx_assert(&interp_list_mtx, MA_NOTOWNED);
157 ibe = malloc(sizeof(*ibe), M_BINMISC, M_WAITOK|M_ZERO);
159 ibe->ibe_name = malloc(namesz, M_BINMISC, M_WAITOK|M_ZERO);
160 strlcpy(ibe->ibe_name, xbe->xbe_name, namesz);
162 imgact_binmisc_populate_interp(xbe->xbe_interpreter, ibe);
164 ibe->ibe_magic = malloc(xbe->xbe_msize, M_BINMISC, M_WAITOK|M_ZERO);
165 memcpy(ibe->ibe_magic, xbe->xbe_magic, xbe->xbe_msize);
167 ibe->ibe_mask = malloc(xbe->xbe_msize, M_BINMISC, M_WAITOK|M_ZERO);
168 memcpy(ibe->ibe_mask, xbe->xbe_mask, xbe->xbe_msize);
170 ibe->ibe_moffset = xbe->xbe_moffset;
171 ibe->ibe_msize = xbe->xbe_msize;
172 ibe->ibe_flags = xbe->xbe_flags;
178 * Free the allocated memory for a given list item.
181 imgact_binmisc_destroy_entry(imgact_binmisc_entry_t *ibe)
186 free(ibe->ibe_magic, M_BINMISC);
188 free(ibe->ibe_mask, M_BINMISC);
189 if (ibe->ibe_interpreter)
190 free(ibe->ibe_interpreter, M_BINMISC);
192 free(ibe->ibe_name, M_BINMISC);
194 free(ibe, M_BINMISC);
198 * Find the interpreter in the list by the given name. Return NULL if not
201 static imgact_binmisc_entry_t *
202 imgact_binmisc_find_entry(char *name)
204 imgact_binmisc_entry_t *ibe;
206 mtx_assert(&interp_list_mtx, MA_OWNED);
208 SLIST_FOREACH(ibe, &interpreter_list, link) {
209 if (strncmp(name, ibe->ibe_name, IBE_NAME_MAX) == 0)
217 * Add the given interpreter if it doesn't already exist. Return EEXIST
218 * if the name already exist in the interpreter list.
221 imgact_binmisc_add_entry(ximgact_binmisc_entry_t *xbe)
223 imgact_binmisc_entry_t *ibe;
227 if (xbe->xbe_msize > IBE_MAGIC_MAX)
230 for(cnt = 0, p = xbe->xbe_name; *p != 0; cnt++, p++)
231 if (cnt >= IBE_NAME_MAX || !isascii((int)*p))
234 for(cnt = 0, p = xbe->xbe_interpreter; *p != 0; cnt++, p++)
235 if (cnt >= IBE_INTERP_LEN_MAX || !isascii((int)*p))
238 /* Make sure we don't have any invalid #'s. */
239 p = xbe->xbe_interpreter;
259 /* Anything besides the above is invalid. */
264 mtx_lock(&interp_list_mtx);
265 if (imgact_binmisc_find_entry(xbe->xbe_name) != NULL) {
266 mtx_unlock(&interp_list_mtx);
269 mtx_unlock(&interp_list_mtx);
271 ibe = imgact_binmisc_new_entry(xbe);
273 mtx_lock(&interp_list_mtx);
274 SLIST_INSERT_HEAD(&interpreter_list, ibe, link);
275 interp_list_entry_count++;
276 mtx_unlock(&interp_list_mtx);
282 * Remove the interpreter in the list with the given name. Return ENOENT
286 imgact_binmisc_remove_entry(char *name)
288 imgact_binmisc_entry_t *ibe;
290 mtx_lock(&interp_list_mtx);
291 if ((ibe = imgact_binmisc_find_entry(name)) == NULL) {
292 mtx_unlock(&interp_list_mtx);
295 SLIST_REMOVE(&interpreter_list, ibe, imgact_binmisc_entry, link);
296 interp_list_entry_count--;
297 mtx_unlock(&interp_list_mtx);
299 imgact_binmisc_destroy_entry(ibe);
305 * Disable the interpreter in the list with the given name. Return ENOENT
309 imgact_binmisc_disable_entry(char *name)
311 imgact_binmisc_entry_t *ibe;
313 mtx_lock(&interp_list_mtx);
314 if ((ibe = imgact_binmisc_find_entry(name)) == NULL) {
315 mtx_unlock(&interp_list_mtx);
319 ibe->ibe_flags &= ~IBF_ENABLED;
320 mtx_unlock(&interp_list_mtx);
326 * Enable the interpreter in the list with the given name. Return ENOENT
330 imgact_binmisc_enable_entry(char *name)
332 imgact_binmisc_entry_t *ibe;
334 mtx_lock(&interp_list_mtx);
335 if ((ibe = imgact_binmisc_find_entry(name)) == NULL) {
336 mtx_unlock(&interp_list_mtx);
340 ibe->ibe_flags |= IBF_ENABLED;
341 mtx_unlock(&interp_list_mtx);
347 imgact_binmisc_populate_xbe(ximgact_binmisc_entry_t *xbe,
348 imgact_binmisc_entry_t *ibe)
352 mtx_assert(&interp_list_mtx, MA_OWNED);
354 bzero(xbe, sizeof(*xbe));
355 strlcpy(xbe->xbe_name, ibe->ibe_name, IBE_NAME_MAX);
357 /* Copy interpreter string. Replace NULL breaks with space. */
358 memcpy(xbe->xbe_interpreter, ibe->ibe_interpreter,
359 ibe->ibe_interp_length);
360 for(i = 0; i < (ibe->ibe_interp_length - 1); i++)
361 if (xbe->xbe_interpreter[i] == '\0')
362 xbe->xbe_interpreter[i] = ' ';
364 memcpy(xbe->xbe_magic, ibe->ibe_magic, ibe->ibe_msize);
365 memcpy(xbe->xbe_mask, ibe->ibe_mask, ibe->ibe_msize);
366 xbe->xbe_version = IBE_VERSION;
367 xbe->xbe_flags = ibe->ibe_flags;
368 xbe->xbe_moffset = ibe->ibe_moffset;
369 xbe->xbe_msize = ibe->ibe_msize;
375 * Retrieve the interpreter with the give name and populate the
376 * ximgact_binmisc_entry structure. Return ENOENT if not found.
379 imgact_binmisc_lookup_entry(char *name, ximgact_binmisc_entry_t *xbe)
381 imgact_binmisc_entry_t *ibe;
384 mtx_lock(&interp_list_mtx);
385 if ((ibe = imgact_binmisc_find_entry(name)) == NULL) {
386 mtx_unlock(&interp_list_mtx);
390 error = imgact_binmisc_populate_xbe(xbe, ibe);
391 mtx_unlock(&interp_list_mtx);
397 * Get a snapshot of all the interpreter entries in the list.
400 imgact_binmisc_get_all_entries(struct sysctl_req *req)
402 ximgact_binmisc_entry_t *xbe, *xbep;
403 imgact_binmisc_entry_t *ibe;
404 int error = 0, count;
406 mtx_lock(&interp_list_mtx);
407 count = interp_list_entry_count;
408 /* Don't block in malloc() while holding lock. */
409 xbe = malloc(sizeof(*xbe) * count, M_BINMISC, M_NOWAIT|M_ZERO);
411 mtx_unlock(&interp_list_mtx);
416 SLIST_FOREACH(ibe, &interpreter_list, link) {
417 error = imgact_binmisc_populate_xbe(xbep++, ibe);
421 mtx_unlock(&interp_list_mtx);
424 error = SYSCTL_OUT(req, xbe, sizeof(*xbe) * count);
426 free(xbe, M_BINMISC);
431 * sysctl() handler for munipulating interpretor table.
432 * Not MP safe (locked by sysctl).
435 sysctl_kern_binmisc(SYSCTL_HANDLER_ARGS)
437 ximgact_binmisc_entry_t xbe;
442 /* Add an entry. Limited to IBE_MAX_ENTRIES. */
443 error = SYSCTL_IN(req, &xbe, sizeof(xbe));
446 if (IBE_VERSION != xbe.xbe_version)
448 if (interp_list_entry_count == IBE_MAX_ENTRIES)
450 error = imgact_binmisc_add_entry(&xbe);
454 /* Remove an entry. */
455 error = SYSCTL_IN(req, &xbe, sizeof(xbe));
458 if (IBE_VERSION != xbe.xbe_version)
460 error = imgact_binmisc_remove_entry(xbe.xbe_name);
464 /* Disable an entry. */
465 error = SYSCTL_IN(req, &xbe, sizeof(xbe));
468 if (IBE_VERSION != xbe.xbe_version)
470 error = imgact_binmisc_disable_entry(xbe.xbe_name);
474 /* Enable an entry. */
475 error = SYSCTL_IN(req, &xbe, sizeof(xbe));
478 if (IBE_VERSION != xbe.xbe_version)
480 error = imgact_binmisc_enable_entry(xbe.xbe_name);
484 /* Lookup an entry. */
485 error = SYSCTL_IN(req, &xbe, sizeof(xbe));
488 if (IBE_VERSION != xbe.xbe_version)
490 error = imgact_binmisc_lookup_entry(xbe.xbe_name, &xbe);
492 error = SYSCTL_OUT(req, &xbe, sizeof(xbe));
496 /* Return a snapshot of the interpretor list. */
499 /* No pointer then just return the list size. */
500 error = SYSCTL_OUT(req, 0, interp_list_entry_count *
501 sizeof(ximgact_binmisc_entry_t));
507 error = imgact_binmisc_get_all_entries(req);
517 SYSCTL_NODE(_kern, OID_AUTO, binmisc, CTLFLAG_RW, 0,
518 "Image activator for miscellaneous binaries");
520 SYSCTL_PROC(_kern_binmisc, OID_AUTO, add,
521 CTLFLAG_MPSAFE|CTLTYPE_STRUCT|CTLFLAG_WR, NULL, IBC_ADD,
522 sysctl_kern_binmisc, "S,ximgact_binmisc_entry",
523 "Add an activator entry");
525 SYSCTL_PROC(_kern_binmisc, OID_AUTO, remove,
526 CTLFLAG_MPSAFE|CTLTYPE_STRUCT|CTLFLAG_WR, NULL, IBC_REMOVE,
527 sysctl_kern_binmisc, "S,ximgact_binmisc_entry",
528 "Remove an activator entry");
530 SYSCTL_PROC(_kern_binmisc, OID_AUTO, disable,
531 CTLFLAG_MPSAFE|CTLTYPE_STRUCT|CTLFLAG_WR, NULL, IBC_DISABLE,
532 sysctl_kern_binmisc, "S,ximgact_binmisc_entry",
533 "Disable an activator entry");
535 SYSCTL_PROC(_kern_binmisc, OID_AUTO, enable,
536 CTLFLAG_MPSAFE|CTLTYPE_STRUCT|CTLFLAG_WR, NULL, IBC_ENABLE,
537 sysctl_kern_binmisc, "S,ximgact_binmisc_entry",
538 "Enable an activator entry");
540 SYSCTL_PROC(_kern_binmisc, OID_AUTO, lookup,
541 CTLFLAG_MPSAFE|CTLTYPE_STRUCT|CTLFLAG_RW|CTLFLAG_ANYBODY, NULL, IBC_LOOKUP,
542 sysctl_kern_binmisc, "S,ximgact_binmisc_entry",
543 "Lookup an activator entry");
545 SYSCTL_PROC(_kern_binmisc, OID_AUTO, list,
546 CTLFLAG_MPSAFE|CTLTYPE_STRUCT|CTLFLAG_RD|CTLFLAG_ANYBODY, NULL, IBC_LIST,
547 sysctl_kern_binmisc, "S,ximgact_binmisc_entry",
548 "Get snapshot of all the activator entries");
550 static imgact_binmisc_entry_t *
551 imgact_binmisc_find_interpreter(const char *image_header)
553 imgact_binmisc_entry_t *ibe;
558 mtx_assert(&interp_list_mtx, MA_OWNED);
560 SLIST_FOREACH(ibe, &interpreter_list, link) {
561 if (!(IBF_ENABLED & ibe->ibe_flags))
564 p = image_header + ibe->ibe_moffset;
566 if (IBF_USE_MASK & ibe->ibe_flags) {
567 /* Compare using mask. */
568 for (i = 0; i < sz; i++)
569 if ((*p++ ^ ibe->ibe_magic[i]) &
573 for (i = 0; i < sz; i++)
574 if (*p++ ^ ibe->ibe_magic[i])
577 if (i == ibe->ibe_msize)
584 imgact_binmisc_exec(struct image_params *imgp)
586 const char *image_header = imgp->image_header;
587 const char *fname = NULL;
590 imgact_binmisc_entry_t *ibe;
594 /* Do we have an interpreter for the given image header? */
595 mtx_lock(&interp_list_mtx);
596 if ((ibe = imgact_binmisc_find_interpreter(image_header)) == NULL) {
597 mtx_unlock(&interp_list_mtx);
601 /* No interpreter nesting allowed. */
602 if (imgp->interpreted & IMGACT_BINMISC) {
603 mtx_unlock(&interp_list_mtx);
607 imgp->interpreted |= IMGACT_BINMISC;
609 if (imgp->args->fname != NULL) {
610 fname = imgp->args->fname;
613 /* Use the fdescfs(5) path for fexecve(2). */
614 sname = sbuf_new_auto();
615 sbuf_printf(sname, "/dev/fd/%d", imgp->args->fd);
617 fname = sbuf_data(sname);
622 * We need to "push" the interpreter in the arg[] list. To do this,
623 * we first shift all the other values in the `begin_argv' area to
624 * provide the exact amount of room for the values added. Set up
625 * `offset' as the number of bytes to be added to the `begin_argv'
628 offset = ibe->ibe_interp_length;
630 /* Adjust the offset for #'s. */
631 s = ibe->ibe_interpreter;
640 /* "##" -> "#": reduce offset by one. */
645 /* "#a" -> (old argv0): increase offset to fit fname */
646 offset += strlen(fname) - 2;
650 /* Hmm... This shouldn't happen. */
651 mtx_unlock(&interp_list_mtx);
652 printf("%s: Unknown macro #%c sequence in "
653 "interpreter string\n", KMOD_NAME, *(s + 1));
660 /* Check to make sure we won't overrun the stringspace. */
661 if (offset > imgp->args->stringspace) {
662 mtx_unlock(&interp_list_mtx);
667 /* Make room for the interpreter */
668 bcopy(imgp->args->begin_argv, imgp->args->begin_argv + offset,
669 imgp->args->endp - imgp->args->begin_argv);
671 /* Adjust everything by the offset. */
672 imgp->args->begin_envv += offset;
673 imgp->args->endp += offset;
674 imgp->args->stringspace -= offset;
676 /* Add the new argument(s) in the count. */
677 imgp->args->argc += ibe->ibe_interp_argcnt;
680 * The original arg[] list has been shifted appropriately. Copy in
681 * the interpreter path.
683 s = ibe->ibe_interpreter;
684 d = imgp->args->begin_argv;
688 /* Handle "#" in interpreter string. */
692 /* "##": Replace with a single '#' */
697 /* "#a": Replace with old arg0 (fname). */
698 if ((l = strlen(fname)) != 0) {
705 /* Shouldn't happen but skip it if it does. */
711 /* Replace space with NUL to separate arguments. */
722 mtx_unlock(&interp_list_mtx);
725 imgp->interpreter_name = imgp->args->begin_argv;
735 imgact_binmisc_init(void *arg)
738 mtx_init(&interp_list_mtx, KMOD_NAME, NULL, MTX_DEF);
742 imgact_binmisc_fini(void *arg)
744 imgact_binmisc_entry_t *ibe, *ibe_tmp;
746 /* Free all the interpreters. */
747 mtx_lock(&interp_list_mtx);
748 SLIST_FOREACH_SAFE(ibe, &interpreter_list, link, ibe_tmp) {
749 SLIST_REMOVE(&interpreter_list, ibe, imgact_binmisc_entry,
751 imgact_binmisc_destroy_entry(ibe);
753 mtx_unlock(&interp_list_mtx);
755 mtx_destroy(&interp_list_mtx);
758 SYSINIT(imgact_binmisc, SI_SUB_EXEC, SI_ORDER_MIDDLE, imgact_binmisc_init, 0);
759 SYSUNINIT(imgact_binmisc, SI_SUB_EXEC, SI_ORDER_MIDDLE, imgact_binmisc_fini, 0);
762 * Tell kern_execve.c about it, with a little help from the linker.
764 static struct execsw imgact_binmisc_execsw = { imgact_binmisc_exec, KMOD_NAME };
765 EXEC_SET(imgact_binmisc, imgact_binmisc_execsw);