2 * Copyright (c) 2013-15, 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 #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 {
69 uint8_t *ibe_interpreter;
70 uint32_t ibe_interp_argcnt;
71 uint32_t ibe_interp_length;
73 SLIST_ENTRY(imgact_binmisc_entry) link;
74 } imgact_binmisc_entry_t;
79 #define IBC_ADD 1 /* Add given entry. */
80 #define IBC_REMOVE 2 /* Remove entry for a given name. */
81 #define IBC_DISABLE 3 /* Disable entry for a given name. */
82 #define IBC_ENABLE 4 /* Enable entry for a given name. */
83 #define IBC_LOOKUP 5 /* Lookup and return entry for given name. */
84 #define IBC_LIST 6 /* Get a snapshot of the interpretor list. */
87 * Interpreter string macros.
89 * They all start with '#' followed by a single letter:
91 #define ISM_POUND '#' /* "##" is the escape sequence for single #. */
92 #define ISM_OLD_ARGV0 'a' /* "#a" is replaced with the old argv0. */
94 MALLOC_DEFINE(M_BINMISC, KMOD_NAME, "misc binary image activator");
96 /* The interpreter list. */
97 static SLIST_HEAD(, imgact_binmisc_entry) interpreter_list =
98 SLIST_HEAD_INITIALIZER(interpreter_list);
100 static int interp_list_entry_count = 0;
102 static struct sx interp_list_sx;
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];
114 memset(t, 0, sizeof(t));
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 ibe = malloc(sizeof(*ibe), M_BINMISC, M_WAITOK|M_ZERO);
157 ibe->ibe_name = malloc(namesz, M_BINMISC, M_WAITOK|M_ZERO);
158 strlcpy(ibe->ibe_name, xbe->xbe_name, namesz);
160 imgact_binmisc_populate_interp(xbe->xbe_interpreter, ibe);
162 ibe->ibe_magic = malloc(xbe->xbe_msize, M_BINMISC, M_WAITOK|M_ZERO);
163 memcpy(ibe->ibe_magic, xbe->xbe_magic, xbe->xbe_msize);
165 ibe->ibe_mask = malloc(xbe->xbe_msize, M_BINMISC, M_WAITOK|M_ZERO);
166 memcpy(ibe->ibe_mask, xbe->xbe_mask, xbe->xbe_msize);
168 ibe->ibe_moffset = xbe->xbe_moffset;
169 ibe->ibe_msize = xbe->xbe_msize;
170 ibe->ibe_flags = xbe->xbe_flags;
176 * Free the allocated memory for a given list item.
179 imgact_binmisc_destroy_entry(imgact_binmisc_entry_t *ibe)
184 free(ibe->ibe_magic, M_BINMISC);
186 free(ibe->ibe_mask, M_BINMISC);
187 if (ibe->ibe_interpreter)
188 free(ibe->ibe_interpreter, M_BINMISC);
190 free(ibe->ibe_name, M_BINMISC);
192 free(ibe, M_BINMISC);
196 * Find the interpreter in the list by the given name. Return NULL if not
199 static imgact_binmisc_entry_t *
200 imgact_binmisc_find_entry(char *name)
202 imgact_binmisc_entry_t *ibe;
204 sx_assert(&interp_list_sx, SA_LOCKED);
206 SLIST_FOREACH(ibe, &interpreter_list, link) {
207 if (strncmp(name, ibe->ibe_name, IBE_NAME_MAX) == 0)
215 * Add the given interpreter if it doesn't already exist. Return EEXIST
216 * if the name already exist in the interpreter list.
219 imgact_binmisc_add_entry(ximgact_binmisc_entry_t *xbe)
221 imgact_binmisc_entry_t *ibe;
224 if (xbe->xbe_msize > IBE_MAGIC_MAX)
227 for(p = xbe->xbe_name; *p != 0; p++)
228 if (!isascii((int)*p))
231 for(p = xbe->xbe_interpreter; *p != 0; p++)
232 if (!isascii((int)*p))
235 /* Make sure we don't have any invalid #'s. */
236 p = xbe->xbe_interpreter;
256 /* Anything besides the above is invalid. */
261 sx_xlock(&interp_list_sx);
262 if (imgact_binmisc_find_entry(xbe->xbe_name) != NULL) {
263 sx_xunlock(&interp_list_sx);
267 /* Preallocate a new entry. */
268 ibe = imgact_binmisc_new_entry(xbe);
272 SLIST_INSERT_HEAD(&interpreter_list, ibe, link);
273 interp_list_entry_count++;
274 sx_xunlock(&interp_list_sx);
280 * Remove the interpreter in the list with the given name. Return ENOENT
284 imgact_binmisc_remove_entry(char *name)
286 imgact_binmisc_entry_t *ibe;
288 sx_xlock(&interp_list_sx);
289 if ((ibe = imgact_binmisc_find_entry(name)) == NULL) {
290 sx_xunlock(&interp_list_sx);
293 SLIST_REMOVE(&interpreter_list, ibe, imgact_binmisc_entry, link);
294 interp_list_entry_count--;
295 sx_xunlock(&interp_list_sx);
297 imgact_binmisc_destroy_entry(ibe);
303 * Disable the interpreter in the list with the given name. Return ENOENT
307 imgact_binmisc_disable_entry(char *name)
309 imgact_binmisc_entry_t *ibe;
311 sx_xlock(&interp_list_sx);
312 if ((ibe = imgact_binmisc_find_entry(name)) == NULL) {
313 sx_xunlock(&interp_list_sx);
317 ibe->ibe_flags &= ~IBF_ENABLED;
318 sx_xunlock(&interp_list_sx);
324 * Enable the interpreter in the list with the given name. Return ENOENT
328 imgact_binmisc_enable_entry(char *name)
330 imgact_binmisc_entry_t *ibe;
332 sx_xlock(&interp_list_sx);
333 if ((ibe = imgact_binmisc_find_entry(name)) == NULL) {
334 sx_xunlock(&interp_list_sx);
338 ibe->ibe_flags |= IBF_ENABLED;
339 sx_xunlock(&interp_list_sx);
345 imgact_binmisc_populate_xbe(ximgact_binmisc_entry_t *xbe,
346 imgact_binmisc_entry_t *ibe)
350 sx_assert(&interp_list_sx, SA_LOCKED);
352 memset(xbe, 0, sizeof(*xbe));
353 strlcpy(xbe->xbe_name, ibe->ibe_name, IBE_NAME_MAX);
355 /* Copy interpreter string. Replace NULL breaks with space. */
356 memcpy(xbe->xbe_interpreter, ibe->ibe_interpreter,
357 ibe->ibe_interp_length);
358 for(i = 0; i < (ibe->ibe_interp_length - 1); i++)
359 if (xbe->xbe_interpreter[i] == '\0')
360 xbe->xbe_interpreter[i] = ' ';
362 memcpy(xbe->xbe_magic, ibe->ibe_magic, ibe->ibe_msize);
363 memcpy(xbe->xbe_mask, ibe->ibe_mask, ibe->ibe_msize);
364 xbe->xbe_version = IBE_VERSION;
365 xbe->xbe_flags = ibe->ibe_flags;
366 xbe->xbe_moffset = ibe->ibe_moffset;
367 xbe->xbe_msize = ibe->ibe_msize;
373 * Retrieve the interpreter with the give name and populate the
374 * ximgact_binmisc_entry structure. Return ENOENT if not found.
377 imgact_binmisc_lookup_entry(char *name, ximgact_binmisc_entry_t *xbe)
379 imgact_binmisc_entry_t *ibe;
382 sx_slock(&interp_list_sx);
383 if ((ibe = imgact_binmisc_find_entry(name)) == NULL) {
384 sx_sunlock(&interp_list_sx);
388 error = imgact_binmisc_populate_xbe(xbe, ibe);
389 sx_sunlock(&interp_list_sx);
395 * Get a snapshot of all the interpreter entries in the list.
398 imgact_binmisc_get_all_entries(struct sysctl_req *req)
400 ximgact_binmisc_entry_t *xbe, *xbep;
401 imgact_binmisc_entry_t *ibe;
402 int error = 0, count;
404 sx_slock(&interp_list_sx);
405 count = interp_list_entry_count;
406 xbe = malloc(sizeof(*xbe) * count, M_BINMISC, M_WAITOK|M_ZERO);
409 SLIST_FOREACH(ibe, &interpreter_list, link) {
410 error = imgact_binmisc_populate_xbe(xbep++, ibe);
414 sx_sunlock(&interp_list_sx);
417 error = SYSCTL_OUT(req, xbe, sizeof(*xbe) * count);
419 free(xbe, M_BINMISC);
424 * sysctl() handler for munipulating interpretor table.
425 * Not MP safe (locked by sysctl).
428 sysctl_kern_binmisc(SYSCTL_HANDLER_ARGS)
430 ximgact_binmisc_entry_t xbe;
435 /* Add an entry. Limited to IBE_MAX_ENTRIES. */
436 error = SYSCTL_IN(req, &xbe, sizeof(xbe));
439 if (IBE_VERSION != xbe.xbe_version)
441 if (interp_list_entry_count == IBE_MAX_ENTRIES)
443 error = imgact_binmisc_add_entry(&xbe);
447 /* Remove an entry. */
448 error = SYSCTL_IN(req, &xbe, sizeof(xbe));
451 if (IBE_VERSION != xbe.xbe_version)
453 error = imgact_binmisc_remove_entry(xbe.xbe_name);
457 /* Disable an entry. */
458 error = SYSCTL_IN(req, &xbe, sizeof(xbe));
461 if (IBE_VERSION != xbe.xbe_version)
463 error = imgact_binmisc_disable_entry(xbe.xbe_name);
467 /* Enable an entry. */
468 error = SYSCTL_IN(req, &xbe, sizeof(xbe));
471 if (IBE_VERSION != xbe.xbe_version)
473 error = imgact_binmisc_enable_entry(xbe.xbe_name);
477 /* Lookup an entry. */
478 error = SYSCTL_IN(req, &xbe, sizeof(xbe));
481 if (IBE_VERSION != xbe.xbe_version)
483 error = imgact_binmisc_lookup_entry(xbe.xbe_name, &xbe);
485 error = SYSCTL_OUT(req, &xbe, sizeof(xbe));
489 /* Return a snapshot of the interpretor list. */
492 /* No pointer then just return the list size. */
493 error = SYSCTL_OUT(req, 0, interp_list_entry_count *
494 sizeof(ximgact_binmisc_entry_t));
500 error = imgact_binmisc_get_all_entries(req);
510 SYSCTL_NODE(_kern, OID_AUTO, binmisc, CTLFLAG_RW, 0,
511 "Image activator for miscellaneous binaries");
513 SYSCTL_PROC(_kern_binmisc, OID_AUTO, add,
514 CTLFLAG_MPSAFE|CTLTYPE_STRUCT|CTLFLAG_WR, NULL, IBC_ADD,
515 sysctl_kern_binmisc, "S,ximgact_binmisc_entry",
516 "Add an activator entry");
518 SYSCTL_PROC(_kern_binmisc, OID_AUTO, remove,
519 CTLFLAG_MPSAFE|CTLTYPE_STRUCT|CTLFLAG_WR, NULL, IBC_REMOVE,
520 sysctl_kern_binmisc, "S,ximgact_binmisc_entry",
521 "Remove an activator entry");
523 SYSCTL_PROC(_kern_binmisc, OID_AUTO, disable,
524 CTLFLAG_MPSAFE|CTLTYPE_STRUCT|CTLFLAG_WR, NULL, IBC_DISABLE,
525 sysctl_kern_binmisc, "S,ximgact_binmisc_entry",
526 "Disable an activator entry");
528 SYSCTL_PROC(_kern_binmisc, OID_AUTO, enable,
529 CTLFLAG_MPSAFE|CTLTYPE_STRUCT|CTLFLAG_WR, NULL, IBC_ENABLE,
530 sysctl_kern_binmisc, "S,ximgact_binmisc_entry",
531 "Enable an activator entry");
533 SYSCTL_PROC(_kern_binmisc, OID_AUTO, lookup,
534 CTLFLAG_MPSAFE|CTLTYPE_STRUCT|CTLFLAG_RW|CTLFLAG_ANYBODY, NULL, IBC_LOOKUP,
535 sysctl_kern_binmisc, "S,ximgact_binmisc_entry",
536 "Lookup an activator entry");
538 SYSCTL_PROC(_kern_binmisc, OID_AUTO, list,
539 CTLFLAG_MPSAFE|CTLTYPE_STRUCT|CTLFLAG_RD|CTLFLAG_ANYBODY, NULL, IBC_LIST,
540 sysctl_kern_binmisc, "S,ximgact_binmisc_entry",
541 "Get snapshot of all the activator entries");
543 static imgact_binmisc_entry_t *
544 imgact_binmisc_find_interpreter(const char *image_header)
546 imgact_binmisc_entry_t *ibe;
551 sx_assert(&interp_list_sx, SA_LOCKED);
553 SLIST_FOREACH(ibe, &interpreter_list, link) {
554 if (!(IBF_ENABLED & ibe->ibe_flags))
557 p = image_header + ibe->ibe_moffset;
559 if (IBF_USE_MASK & ibe->ibe_flags) {
560 /* Compare using mask. */
561 for (i = 0; i < sz; i++)
562 if ((*p++ ^ ibe->ibe_magic[i]) &
566 for (i = 0; i < sz; i++)
567 if (*p++ ^ ibe->ibe_magic[i])
570 if (i == ibe->ibe_msize)
577 imgact_binmisc_exec(struct image_params *imgp)
579 const char *image_header = imgp->image_header;
580 const char *fname = NULL;
583 imgact_binmisc_entry_t *ibe;
587 /* Do we have an interpreter for the given image header? */
588 sx_slock(&interp_list_sx);
589 if ((ibe = imgact_binmisc_find_interpreter(image_header)) == NULL) {
590 sx_sunlock(&interp_list_sx);
594 /* No interpreter nesting allowed. */
595 if (imgp->interpreted & IMGACT_BINMISC) {
596 sx_sunlock(&interp_list_sx);
600 imgp->interpreted |= IMGACT_BINMISC;
602 if (imgp->args->fname != NULL) {
603 fname = imgp->args->fname;
606 /* Use the fdescfs(5) path for fexecve(2). */
607 sname = sbuf_new_auto();
608 sbuf_printf(sname, "/dev/fd/%d", imgp->args->fd);
610 fname = sbuf_data(sname);
615 * We need to "push" the interpreter in the arg[] list. To do this,
616 * we first shift all the other values in the `begin_argv' area to
617 * provide the exact amount of room for the values added. Set up
618 * `offset' as the number of bytes to be added to the `begin_argv'
621 offset = ibe->ibe_interp_length;
623 /* Adjust the offset for #'s. */
624 s = ibe->ibe_interpreter;
633 /* "##" -> "#": reduce offset by one. */
638 /* "#a" -> (old argv0): increase offset to fit fname */
639 offset += strlen(fname) - 2;
643 /* Hmm... This shouldn't happen. */
644 sx_sunlock(&interp_list_sx);
645 printf("%s: Unknown macro #%c sequence in "
646 "interpreter string\n", KMOD_NAME, *(s + 1));
653 /* Check to make sure we won't overrun the stringspace. */
654 if (offset > imgp->args->stringspace) {
655 sx_sunlock(&interp_list_sx);
660 /* Make room for the interpreter */
661 bcopy(imgp->args->begin_argv, imgp->args->begin_argv + offset,
662 imgp->args->endp - imgp->args->begin_argv);
664 /* Adjust everything by the offset. */
665 imgp->args->begin_envv += offset;
666 imgp->args->endp += offset;
667 imgp->args->stringspace -= offset;
669 /* Add the new argument(s) in the count. */
670 imgp->args->argc += ibe->ibe_interp_argcnt;
673 * The original arg[] list has been shifted appropriately. Copy in
674 * the interpreter path.
676 s = ibe->ibe_interpreter;
677 d = imgp->args->begin_argv;
681 /* Handle "#" in interpreter string. */
685 /* "##": Replace with a single '#' */
690 /* "#a": Replace with old arg0 (fname). */
691 if ((l = strlen(fname)) != 0) {
698 /* Shouldn't happen but skip it if it does. */
704 /* Replace space with NUL to seperate arguments. */
715 sx_sunlock(&interp_list_sx);
718 imgp->interpreter_name = imgp->args->begin_argv;
728 imgact_binmisc_init(void *arg)
731 sx_init(&interp_list_sx, KMOD_NAME);
735 imgact_binmisc_fini(void *arg)
737 imgact_binmisc_entry_t *ibe, *ibe_tmp;
739 /* Free all the interpreters. */
740 sx_xlock(&interp_list_sx);
741 SLIST_FOREACH_SAFE(ibe, &interpreter_list, link, ibe_tmp) {
742 SLIST_REMOVE(&interpreter_list, ibe, imgact_binmisc_entry,
744 imgact_binmisc_destroy_entry(ibe);
746 sx_xunlock(&interp_list_sx);
748 sx_destroy(&interp_list_sx);
751 SYSINIT(imgact_binmisc, SI_SUB_EXEC, SI_ORDER_MIDDLE, imgact_binmisc_init, 0);
752 SYSUNINIT(imgact_binmisc, SI_SUB_EXEC, SI_ORDER_MIDDLE, imgact_binmisc_fini, 0);
755 * Tell kern_execve.c about it, with a little help from the linker.
757 static struct execsw imgact_binmisc_execsw = { imgact_binmisc_exec, KMOD_NAME };
758 EXEC_SET(imgact_binmisc, imgact_binmisc_execsw);