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 #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;
225 if (xbe->xbe_msize > IBE_MAGIC_MAX)
228 for(cnt = 0, p = xbe->xbe_name; *p != 0; cnt++, p++)
229 if (cnt >= IBE_NAME_MAX || !isascii((int)*p))
232 for(cnt = 0, p = xbe->xbe_interpreter; *p != 0; cnt++, p++)
233 if (cnt >= IBE_INTERP_LEN_MAX || !isascii((int)*p))
236 /* Make sure we don't have any invalid #'s. */
237 p = xbe->xbe_interpreter;
257 /* Anything besides the above is invalid. */
262 sx_xlock(&interp_list_sx);
263 if (imgact_binmisc_find_entry(xbe->xbe_name) != NULL) {
264 sx_xunlock(&interp_list_sx);
268 /* Preallocate a new entry. */
269 ibe = imgact_binmisc_new_entry(xbe);
271 SLIST_INSERT_HEAD(&interpreter_list, ibe, link);
272 interp_list_entry_count++;
273 sx_xunlock(&interp_list_sx);
279 * Remove the interpreter in the list with the given name. Return ENOENT
283 imgact_binmisc_remove_entry(char *name)
285 imgact_binmisc_entry_t *ibe;
287 sx_xlock(&interp_list_sx);
288 if ((ibe = imgact_binmisc_find_entry(name)) == NULL) {
289 sx_xunlock(&interp_list_sx);
292 SLIST_REMOVE(&interpreter_list, ibe, imgact_binmisc_entry, link);
293 interp_list_entry_count--;
294 sx_xunlock(&interp_list_sx);
296 imgact_binmisc_destroy_entry(ibe);
302 * Disable the interpreter in the list with the given name. Return ENOENT
306 imgact_binmisc_disable_entry(char *name)
308 imgact_binmisc_entry_t *ibe;
310 sx_xlock(&interp_list_sx);
311 if ((ibe = imgact_binmisc_find_entry(name)) == NULL) {
312 sx_xunlock(&interp_list_sx);
316 ibe->ibe_flags &= ~IBF_ENABLED;
317 sx_xunlock(&interp_list_sx);
323 * Enable the interpreter in the list with the given name. Return ENOENT
327 imgact_binmisc_enable_entry(char *name)
329 imgact_binmisc_entry_t *ibe;
331 sx_xlock(&interp_list_sx);
332 if ((ibe = imgact_binmisc_find_entry(name)) == NULL) {
333 sx_xunlock(&interp_list_sx);
337 ibe->ibe_flags |= IBF_ENABLED;
338 sx_xunlock(&interp_list_sx);
344 imgact_binmisc_populate_xbe(ximgact_binmisc_entry_t *xbe,
345 imgact_binmisc_entry_t *ibe)
349 sx_assert(&interp_list_sx, SA_LOCKED);
351 memset(xbe, 0, sizeof(*xbe));
352 strlcpy(xbe->xbe_name, ibe->ibe_name, IBE_NAME_MAX);
354 /* Copy interpreter string. Replace NULL breaks with space. */
355 memcpy(xbe->xbe_interpreter, ibe->ibe_interpreter,
356 ibe->ibe_interp_length);
357 for(i = 0; i < (ibe->ibe_interp_length - 1); i++)
358 if (xbe->xbe_interpreter[i] == '\0')
359 xbe->xbe_interpreter[i] = ' ';
361 memcpy(xbe->xbe_magic, ibe->ibe_magic, ibe->ibe_msize);
362 memcpy(xbe->xbe_mask, ibe->ibe_mask, ibe->ibe_msize);
363 xbe->xbe_version = IBE_VERSION;
364 xbe->xbe_flags = ibe->ibe_flags;
365 xbe->xbe_moffset = ibe->ibe_moffset;
366 xbe->xbe_msize = ibe->ibe_msize;
372 * Retrieve the interpreter with the give name and populate the
373 * ximgact_binmisc_entry structure. Return ENOENT if not found.
376 imgact_binmisc_lookup_entry(char *name, ximgact_binmisc_entry_t *xbe)
378 imgact_binmisc_entry_t *ibe;
381 sx_slock(&interp_list_sx);
382 if ((ibe = imgact_binmisc_find_entry(name)) == NULL) {
383 sx_sunlock(&interp_list_sx);
387 error = imgact_binmisc_populate_xbe(xbe, ibe);
388 sx_sunlock(&interp_list_sx);
394 * Get a snapshot of all the interpreter entries in the list.
397 imgact_binmisc_get_all_entries(struct sysctl_req *req)
399 ximgact_binmisc_entry_t *xbe, *xbep;
400 imgact_binmisc_entry_t *ibe;
401 int error = 0, count;
403 sx_slock(&interp_list_sx);
404 count = interp_list_entry_count;
405 xbe = malloc(sizeof(*xbe) * count, M_BINMISC, M_WAITOK|M_ZERO);
408 SLIST_FOREACH(ibe, &interpreter_list, link) {
409 error = imgact_binmisc_populate_xbe(xbep++, ibe);
413 sx_sunlock(&interp_list_sx);
416 error = SYSCTL_OUT(req, xbe, sizeof(*xbe) * count);
418 free(xbe, M_BINMISC);
423 * sysctl() handler for munipulating interpretor table.
424 * Not MP safe (locked by sysctl).
427 sysctl_kern_binmisc(SYSCTL_HANDLER_ARGS)
429 ximgact_binmisc_entry_t xbe;
434 /* Add an entry. Limited to IBE_MAX_ENTRIES. */
435 error = SYSCTL_IN(req, &xbe, sizeof(xbe));
438 if (IBE_VERSION != xbe.xbe_version)
440 if (interp_list_entry_count == IBE_MAX_ENTRIES)
442 error = imgact_binmisc_add_entry(&xbe);
446 /* Remove an entry. */
447 error = SYSCTL_IN(req, &xbe, sizeof(xbe));
450 if (IBE_VERSION != xbe.xbe_version)
452 error = imgact_binmisc_remove_entry(xbe.xbe_name);
456 /* Disable an entry. */
457 error = SYSCTL_IN(req, &xbe, sizeof(xbe));
460 if (IBE_VERSION != xbe.xbe_version)
462 error = imgact_binmisc_disable_entry(xbe.xbe_name);
466 /* Enable an entry. */
467 error = SYSCTL_IN(req, &xbe, sizeof(xbe));
470 if (IBE_VERSION != xbe.xbe_version)
472 error = imgact_binmisc_enable_entry(xbe.xbe_name);
476 /* Lookup an entry. */
477 error = SYSCTL_IN(req, &xbe, sizeof(xbe));
480 if (IBE_VERSION != xbe.xbe_version)
482 error = imgact_binmisc_lookup_entry(xbe.xbe_name, &xbe);
484 error = SYSCTL_OUT(req, &xbe, sizeof(xbe));
488 /* Return a snapshot of the interpretor list. */
491 /* No pointer then just return the list size. */
492 error = SYSCTL_OUT(req, 0, interp_list_entry_count *
493 sizeof(ximgact_binmisc_entry_t));
499 error = imgact_binmisc_get_all_entries(req);
509 SYSCTL_NODE(_kern, OID_AUTO, binmisc, CTLFLAG_RW, 0,
510 "Image activator for miscellaneous binaries");
512 SYSCTL_PROC(_kern_binmisc, OID_AUTO, add,
513 CTLFLAG_MPSAFE|CTLTYPE_STRUCT|CTLFLAG_WR, NULL, IBC_ADD,
514 sysctl_kern_binmisc, "S,ximgact_binmisc_entry",
515 "Add an activator entry");
517 SYSCTL_PROC(_kern_binmisc, OID_AUTO, remove,
518 CTLFLAG_MPSAFE|CTLTYPE_STRUCT|CTLFLAG_WR, NULL, IBC_REMOVE,
519 sysctl_kern_binmisc, "S,ximgact_binmisc_entry",
520 "Remove an activator entry");
522 SYSCTL_PROC(_kern_binmisc, OID_AUTO, disable,
523 CTLFLAG_MPSAFE|CTLTYPE_STRUCT|CTLFLAG_WR, NULL, IBC_DISABLE,
524 sysctl_kern_binmisc, "S,ximgact_binmisc_entry",
525 "Disable an activator entry");
527 SYSCTL_PROC(_kern_binmisc, OID_AUTO, enable,
528 CTLFLAG_MPSAFE|CTLTYPE_STRUCT|CTLFLAG_WR, NULL, IBC_ENABLE,
529 sysctl_kern_binmisc, "S,ximgact_binmisc_entry",
530 "Enable an activator entry");
532 SYSCTL_PROC(_kern_binmisc, OID_AUTO, lookup,
533 CTLFLAG_MPSAFE|CTLTYPE_STRUCT|CTLFLAG_RW|CTLFLAG_ANYBODY, NULL, IBC_LOOKUP,
534 sysctl_kern_binmisc, "S,ximgact_binmisc_entry",
535 "Lookup an activator entry");
537 SYSCTL_PROC(_kern_binmisc, OID_AUTO, list,
538 CTLFLAG_MPSAFE|CTLTYPE_STRUCT|CTLFLAG_RD|CTLFLAG_ANYBODY, NULL, IBC_LIST,
539 sysctl_kern_binmisc, "S,ximgact_binmisc_entry",
540 "Get snapshot of all the activator entries");
542 static imgact_binmisc_entry_t *
543 imgact_binmisc_find_interpreter(const char *image_header)
545 imgact_binmisc_entry_t *ibe;
550 sx_assert(&interp_list_sx, SA_LOCKED);
552 SLIST_FOREACH(ibe, &interpreter_list, link) {
553 if (!(IBF_ENABLED & ibe->ibe_flags))
556 p = image_header + ibe->ibe_moffset;
558 if (IBF_USE_MASK & ibe->ibe_flags) {
559 /* Compare using mask. */
560 for (i = 0; i < sz; i++)
561 if ((*p++ ^ ibe->ibe_magic[i]) &
565 for (i = 0; i < sz; i++)
566 if (*p++ ^ ibe->ibe_magic[i])
569 if (i == ibe->ibe_msize)
576 imgact_binmisc_exec(struct image_params *imgp)
578 const char *image_header = imgp->image_header;
579 const char *fname = NULL;
582 imgact_binmisc_entry_t *ibe;
586 /* Do we have an interpreter for the given image header? */
587 sx_slock(&interp_list_sx);
588 if ((ibe = imgact_binmisc_find_interpreter(image_header)) == NULL) {
589 sx_sunlock(&interp_list_sx);
593 /* No interpreter nesting allowed. */
594 if (imgp->interpreted & IMGACT_BINMISC) {
595 sx_sunlock(&interp_list_sx);
599 imgp->interpreted |= IMGACT_BINMISC;
601 if (imgp->args->fname != NULL) {
602 fname = imgp->args->fname;
605 /* Use the fdescfs(5) path for fexecve(2). */
606 sname = sbuf_new_auto();
607 sbuf_printf(sname, "/dev/fd/%d", imgp->args->fd);
609 fname = sbuf_data(sname);
614 * We need to "push" the interpreter in the arg[] list. To do this,
615 * we first shift all the other values in the `begin_argv' area to
616 * provide the exact amount of room for the values added. Set up
617 * `offset' as the number of bytes to be added to the `begin_argv'
620 offset = ibe->ibe_interp_length;
622 /* Adjust the offset for #'s. */
623 s = ibe->ibe_interpreter;
632 /* "##" -> "#": reduce offset by one. */
637 /* "#a" -> (old argv0): increase offset to fit fname */
638 offset += strlen(fname) - 2;
642 /* Hmm... This shouldn't happen. */
643 sx_sunlock(&interp_list_sx);
644 printf("%s: Unknown macro #%c sequence in "
645 "interpreter string\n", KMOD_NAME, *(s + 1));
652 /* Check to make sure we won't overrun the stringspace. */
653 if (offset > imgp->args->stringspace) {
654 sx_sunlock(&interp_list_sx);
659 /* Make room for the interpreter */
660 bcopy(imgp->args->begin_argv, imgp->args->begin_argv + offset,
661 imgp->args->endp - imgp->args->begin_argv);
663 /* Adjust everything by the offset. */
664 imgp->args->begin_envv += offset;
665 imgp->args->endp += offset;
666 imgp->args->stringspace -= offset;
668 /* Add the new argument(s) in the count. */
669 imgp->args->argc += ibe->ibe_interp_argcnt;
672 * The original arg[] list has been shifted appropriately. Copy in
673 * the interpreter path.
675 s = ibe->ibe_interpreter;
676 d = imgp->args->begin_argv;
680 /* Handle "#" in interpreter string. */
684 /* "##": Replace with a single '#' */
689 /* "#a": Replace with old arg0 (fname). */
690 if ((l = strlen(fname)) != 0) {
697 /* Shouldn't happen but skip it if it does. */
703 /* Replace space with NUL to separate arguments. */
714 sx_sunlock(&interp_list_sx);
717 imgp->interpreter_name = imgp->args->begin_argv;
727 imgact_binmisc_init(void *arg)
730 sx_init(&interp_list_sx, KMOD_NAME);
734 imgact_binmisc_fini(void *arg)
736 imgact_binmisc_entry_t *ibe, *ibe_tmp;
738 /* Free all the interpreters. */
739 sx_xlock(&interp_list_sx);
740 SLIST_FOREACH_SAFE(ibe, &interpreter_list, link, ibe_tmp) {
741 SLIST_REMOVE(&interpreter_list, ibe, imgact_binmisc_entry,
743 imgact_binmisc_destroy_entry(ibe);
745 sx_xunlock(&interp_list_sx);
747 sx_destroy(&interp_list_sx);
750 SYSINIT(imgact_binmisc, SI_SUB_EXEC, SI_ORDER_MIDDLE, imgact_binmisc_init, 0);
751 SYSUNINIT(imgact_binmisc, SI_SUB_EXEC, SI_ORDER_MIDDLE, imgact_binmisc_fini, 0);
754 * Tell kern_execve.c about it, with a little help from the linker.
756 static struct execsw imgact_binmisc_execsw = { imgact_binmisc_exec, KMOD_NAME };
757 EXEC_SET(imgact_binmisc, imgact_binmisc_execsw);