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/param.h>
28 #include <sys/ctype.h>
30 #include <sys/fcntl.h>
31 #include <sys/imgact.h>
32 #include <sys/imgact_binmisc.h>
33 #include <sys/kernel.h>
35 #include <sys/malloc.h>
36 #include <sys/mutex.h>
37 #include <sys/namei.h>
39 #include <sys/sysctl.h>
41 #include <sys/vnode.h>
43 #include <machine/atomic.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 {
61 SLIST_ENTRY(imgact_binmisc_entry) link;
65 uint8_t *ibe_interpreter;
66 struct vnode *ibe_interpreter_vnode;
67 ssize_t ibe_interp_offset;
68 uint32_t ibe_interp_argcnt;
69 uint32_t ibe_interp_length;
70 uint32_t ibe_argv0_cnt;
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;
102 static struct sx interp_list_sx;
104 #define INTERP_LIST_WLOCK() sx_xlock(&interp_list_sx)
105 #define INTERP_LIST_RLOCK() sx_slock(&interp_list_sx)
106 #define INTERP_LIST_WUNLOCK() sx_xunlock(&interp_list_sx)
107 #define INTERP_LIST_RUNLOCK() sx_sunlock(&interp_list_sx)
109 #define INTERP_LIST_LOCK_INIT() sx_init(&interp_list_sx, KMOD_NAME)
110 #define INTERP_LIST_LOCK_DESTROY() sx_destroy(&interp_list_sx)
112 #define INTERP_LIST_ASSERT_LOCKED() sx_assert(&interp_list_sx, SA_LOCKED)
115 * Populate the entry with the information about the interpreter.
118 imgact_binmisc_populate_interp(char *str, imgact_binmisc_entry_t *ibe, int flags)
120 uint32_t len = 0, argc = 1;
121 char t[IBE_INTERP_LEN_MAX];
124 memset(t, 0, sizeof(t));
127 * Normalize interpreter string. Replace white space between args with
131 while (*sp != '\0') {
132 if (*sp == ' ' || *sp == '\t') {
133 if (++len >= IBE_INTERP_LEN_MAX)
137 while (*sp == ' ' || *sp == '\t')
148 ibe->ibe_interpreter = malloc(len, M_BINMISC, M_WAITOK|M_ZERO);
150 /* Populate all the ibe fields for the interpreter. */
151 memcpy(ibe->ibe_interpreter, t, len);
152 ibe->ibe_interp_argcnt = argc;
153 ibe->ibe_interp_length = len;
155 ibe->ibe_interpreter_vnode = NULL;
156 if (flags & IBF_PRE_OPEN) {
161 while (*tp != '\0' && *tp != ' ') {
165 NDINIT(&nd, LOOKUP, FOLLOW | ISOPEN, UIO_SYSSPACE, t);
168 * If there is an error, just stop now and fall back
169 * to the non pre-open case where we lookup during
176 ibe->ibe_interpreter_vnode = nd.ni_vp;
181 * Allocate memory and populate a new entry for the interpreter table.
183 static imgact_binmisc_entry_t *
184 imgact_binmisc_new_entry(ximgact_binmisc_entry_t *xbe, ssize_t interp_offset,
187 imgact_binmisc_entry_t *ibe = NULL;
188 size_t namesz = min(strlen(xbe->xbe_name) + 1, IBE_NAME_MAX);
190 ibe = malloc(sizeof(*ibe), M_BINMISC, M_WAITOK|M_ZERO);
192 ibe->ibe_name = malloc(namesz, M_BINMISC, M_WAITOK|M_ZERO);
193 strlcpy(ibe->ibe_name, xbe->xbe_name, namesz);
195 imgact_binmisc_populate_interp(xbe->xbe_interpreter, ibe, xbe->xbe_flags);
197 ibe->ibe_magic = malloc(xbe->xbe_msize, M_BINMISC, M_WAITOK|M_ZERO);
198 memcpy(ibe->ibe_magic, xbe->xbe_magic, xbe->xbe_msize);
200 ibe->ibe_mask = malloc(xbe->xbe_msize, M_BINMISC, M_WAITOK|M_ZERO);
201 memcpy(ibe->ibe_mask, xbe->xbe_mask, xbe->xbe_msize);
203 ibe->ibe_moffset = xbe->xbe_moffset;
204 ibe->ibe_msize = xbe->xbe_msize;
205 ibe->ibe_flags = xbe->xbe_flags;
206 ibe->ibe_interp_offset = interp_offset;
207 ibe->ibe_argv0_cnt = argv0_cnt;
212 * Free the allocated memory for a given list item.
215 imgact_binmisc_destroy_entry(imgact_binmisc_entry_t *ibe)
220 free(ibe->ibe_magic, M_BINMISC);
222 free(ibe->ibe_mask, M_BINMISC);
223 if (ibe->ibe_interpreter)
224 free(ibe->ibe_interpreter, M_BINMISC);
226 free(ibe->ibe_name, M_BINMISC);
227 if (ibe->ibe_interpreter_vnode)
228 vrele(ibe->ibe_interpreter_vnode);
230 free(ibe, M_BINMISC);
234 * Find the interpreter in the list by the given name. Return NULL if not
237 static imgact_binmisc_entry_t *
238 imgact_binmisc_find_entry(char *name)
240 imgact_binmisc_entry_t *ibe;
242 INTERP_LIST_ASSERT_LOCKED();
244 SLIST_FOREACH(ibe, &interpreter_list, link) {
245 if (strncmp(name, ibe->ibe_name, IBE_NAME_MAX) == 0)
253 * Add the given interpreter if it doesn't already exist. Return EEXIST
254 * if the name already exist in the interpreter list.
257 imgact_binmisc_add_entry(ximgact_binmisc_entry_t *xbe)
259 imgact_binmisc_entry_t *ibe;
261 ssize_t interp_offset;
264 if (xbe->xbe_msize > IBE_MAGIC_MAX)
266 if (xbe->xbe_moffset + xbe->xbe_msize > IBE_MATCH_MAX)
269 for(cnt = 0, p = xbe->xbe_name; *p != 0; cnt++, p++)
270 if (cnt >= IBE_NAME_MAX || !isascii((int)*p))
273 for(cnt = 0, p = xbe->xbe_interpreter; *p != 0; cnt++, p++)
274 if (cnt >= IBE_INTERP_LEN_MAX || !isascii((int)*p))
277 /* Make sure we don't have any invalid #'s. */
278 p = xbe->xbe_interpreter;
281 while ((p = strchr(p, '#')) != NULL) {
296 /* Anything besides the above is invalid. */
302 * Preallocate a new entry. We do this without holding the
303 * lock to avoid lock-order problems if IBF_PRE_OPEN is
306 ibe = imgact_binmisc_new_entry(xbe, interp_offset, argv0_cnt);
309 if (imgact_binmisc_find_entry(xbe->xbe_name) != NULL) {
310 INTERP_LIST_WUNLOCK();
311 imgact_binmisc_destroy_entry(ibe);
315 SLIST_INSERT_HEAD(&interpreter_list, ibe, link);
316 interp_list_entry_count++;
317 INTERP_LIST_WUNLOCK();
323 * Remove the interpreter in the list with the given name. Return ENOENT
327 imgact_binmisc_remove_entry(char *name)
329 imgact_binmisc_entry_t *ibe;
332 if ((ibe = imgact_binmisc_find_entry(name)) == NULL) {
333 INTERP_LIST_WUNLOCK();
336 SLIST_REMOVE(&interpreter_list, ibe, imgact_binmisc_entry, link);
337 interp_list_entry_count--;
338 INTERP_LIST_WUNLOCK();
340 imgact_binmisc_destroy_entry(ibe);
346 * Disable the interpreter in the list with the given name. Return ENOENT
350 imgact_binmisc_disable_entry(char *name)
352 imgact_binmisc_entry_t *ibe;
355 if ((ibe = imgact_binmisc_find_entry(name)) == NULL) {
356 INTERP_LIST_WUNLOCK();
360 ibe->ibe_flags &= ~IBF_ENABLED;
361 INTERP_LIST_WUNLOCK();
367 * Enable the interpreter in the list with the given name. Return ENOENT
371 imgact_binmisc_enable_entry(char *name)
373 imgact_binmisc_entry_t *ibe;
376 if ((ibe = imgact_binmisc_find_entry(name)) == NULL) {
377 INTERP_LIST_WUNLOCK();
381 ibe->ibe_flags |= IBF_ENABLED;
382 INTERP_LIST_WUNLOCK();
388 imgact_binmisc_populate_xbe(ximgact_binmisc_entry_t *xbe,
389 imgact_binmisc_entry_t *ibe)
393 INTERP_LIST_ASSERT_LOCKED();
394 memset(xbe, 0, sizeof(*xbe));
395 strlcpy(xbe->xbe_name, ibe->ibe_name, IBE_NAME_MAX);
397 /* Copy interpreter string. Replace NULL breaks with space. */
398 memcpy(xbe->xbe_interpreter, ibe->ibe_interpreter,
399 ibe->ibe_interp_length);
400 for(i = 0; i < (ibe->ibe_interp_length - 1); i++)
401 if (xbe->xbe_interpreter[i] == '\0')
402 xbe->xbe_interpreter[i] = ' ';
404 memcpy(xbe->xbe_magic, ibe->ibe_magic, ibe->ibe_msize);
405 memcpy(xbe->xbe_mask, ibe->ibe_mask, ibe->ibe_msize);
406 xbe->xbe_version = IBE_VERSION;
407 xbe->xbe_flags = ibe->ibe_flags;
408 xbe->xbe_moffset = ibe->ibe_moffset;
409 xbe->xbe_msize = ibe->ibe_msize;
415 * Retrieve the interpreter with the give name and populate the
416 * ximgact_binmisc_entry structure. Return ENOENT if not found.
419 imgact_binmisc_lookup_entry(char *name, ximgact_binmisc_entry_t *xbe)
421 imgact_binmisc_entry_t *ibe;
425 if ((ibe = imgact_binmisc_find_entry(name)) == NULL) {
426 INTERP_LIST_RUNLOCK();
430 error = imgact_binmisc_populate_xbe(xbe, ibe);
431 INTERP_LIST_RUNLOCK();
437 * Get a snapshot of all the interpreter entries in the list.
440 imgact_binmisc_get_all_entries(struct sysctl_req *req)
442 ximgact_binmisc_entry_t *xbe, *xbep;
443 imgact_binmisc_entry_t *ibe;
444 int error = 0, count;
447 count = interp_list_entry_count;
448 xbe = malloc(sizeof(*xbe) * count, M_BINMISC, M_WAITOK|M_ZERO);
451 SLIST_FOREACH(ibe, &interpreter_list, link) {
452 error = imgact_binmisc_populate_xbe(xbep++, ibe);
456 INTERP_LIST_RUNLOCK();
459 error = SYSCTL_OUT(req, xbe, sizeof(*xbe) * count);
461 free(xbe, M_BINMISC);
466 * sysctl() handler for munipulating interpretor table.
467 * Not MP safe (locked by sysctl).
470 sysctl_kern_binmisc(SYSCTL_HANDLER_ARGS)
472 ximgact_binmisc_entry_t xbe;
477 /* Add an entry. Limited to IBE_MAX_ENTRIES. */
478 error = SYSCTL_IN(req, &xbe, sizeof(xbe));
481 if (IBE_VERSION != xbe.xbe_version)
483 if ((xbe.xbe_flags & ~IBF_VALID_UFLAGS) != 0)
485 if (interp_list_entry_count == IBE_MAX_ENTRIES)
487 error = imgact_binmisc_add_entry(&xbe);
491 /* Remove an entry. */
492 error = SYSCTL_IN(req, &xbe, sizeof(xbe));
495 if (IBE_VERSION != xbe.xbe_version)
497 error = imgact_binmisc_remove_entry(xbe.xbe_name);
501 /* Disable an entry. */
502 error = SYSCTL_IN(req, &xbe, sizeof(xbe));
505 if (IBE_VERSION != xbe.xbe_version)
507 error = imgact_binmisc_disable_entry(xbe.xbe_name);
511 /* Enable an entry. */
512 error = SYSCTL_IN(req, &xbe, sizeof(xbe));
515 if (IBE_VERSION != xbe.xbe_version)
517 error = imgact_binmisc_enable_entry(xbe.xbe_name);
521 /* Lookup an entry. */
522 error = SYSCTL_IN(req, &xbe, sizeof(xbe));
525 if (IBE_VERSION != xbe.xbe_version)
527 error = imgact_binmisc_lookup_entry(xbe.xbe_name, &xbe);
529 error = SYSCTL_OUT(req, &xbe, sizeof(xbe));
533 /* Return a snapshot of the interpretor list. */
536 /* No pointer then just return the list size. */
537 error = SYSCTL_OUT(req, 0, interp_list_entry_count *
538 sizeof(ximgact_binmisc_entry_t));
544 error = imgact_binmisc_get_all_entries(req);
554 SYSCTL_NODE(_kern, OID_AUTO, binmisc, CTLFLAG_RW | CTLFLAG_MPSAFE, 0,
555 "Image activator for miscellaneous binaries");
557 SYSCTL_PROC(_kern_binmisc, OID_AUTO, add,
558 CTLFLAG_MPSAFE|CTLTYPE_STRUCT|CTLFLAG_WR, NULL, IBC_ADD,
559 sysctl_kern_binmisc, "S,ximgact_binmisc_entry",
560 "Add an activator entry");
562 SYSCTL_PROC(_kern_binmisc, OID_AUTO, remove,
563 CTLFLAG_MPSAFE|CTLTYPE_STRUCT|CTLFLAG_WR, NULL, IBC_REMOVE,
564 sysctl_kern_binmisc, "S,ximgact_binmisc_entry",
565 "Remove an activator entry");
567 SYSCTL_PROC(_kern_binmisc, OID_AUTO, disable,
568 CTLFLAG_MPSAFE|CTLTYPE_STRUCT|CTLFLAG_WR, NULL, IBC_DISABLE,
569 sysctl_kern_binmisc, "S,ximgact_binmisc_entry",
570 "Disable an activator entry");
572 SYSCTL_PROC(_kern_binmisc, OID_AUTO, enable,
573 CTLFLAG_MPSAFE|CTLTYPE_STRUCT|CTLFLAG_WR, NULL, IBC_ENABLE,
574 sysctl_kern_binmisc, "S,ximgact_binmisc_entry",
575 "Enable an activator entry");
577 SYSCTL_PROC(_kern_binmisc, OID_AUTO, lookup,
578 CTLFLAG_MPSAFE|CTLTYPE_STRUCT|CTLFLAG_RW|CTLFLAG_ANYBODY, NULL, IBC_LOOKUP,
579 sysctl_kern_binmisc, "S,ximgact_binmisc_entry",
580 "Lookup an activator entry");
582 SYSCTL_PROC(_kern_binmisc, OID_AUTO, list,
583 CTLFLAG_MPSAFE|CTLTYPE_STRUCT|CTLFLAG_RD|CTLFLAG_ANYBODY, NULL, IBC_LIST,
584 sysctl_kern_binmisc, "S,ximgact_binmisc_entry",
585 "Get snapshot of all the activator entries");
587 static imgact_binmisc_entry_t *
588 imgact_binmisc_find_interpreter(const char *image_header)
590 imgact_binmisc_entry_t *ibe;
595 INTERP_LIST_ASSERT_LOCKED();
597 SLIST_FOREACH(ibe, &interpreter_list, link) {
598 if (!(IBF_ENABLED & ibe->ibe_flags))
601 p = image_header + ibe->ibe_moffset;
603 if (IBF_USE_MASK & ibe->ibe_flags) {
604 /* Compare using mask. */
605 for (i = 0; i < sz; i++)
606 if ((*p++ ^ ibe->ibe_magic[i]) &
610 for (i = 0; i < sz; i++)
611 if (*p++ ^ ibe->ibe_magic[i])
614 if (i == ibe->ibe_msize)
621 imgact_binmisc_exec(struct image_params *imgp)
623 const char *image_header = imgp->image_header;
624 const char *fname = NULL;
629 size_t namelen, offset;
630 imgact_binmisc_entry_t *ibe;
636 /* Do we have an interpreter for the given image header? */
638 if ((ibe = imgact_binmisc_find_interpreter(image_header)) == NULL) {
643 /* No interpreter nesting allowed. */
644 if (imgp->interpreted & IMGACT_BINMISC) {
649 imgp->interpreted |= IMGACT_BINMISC;
652 * Don't bother with the overhead of putting fname together if we're not
655 if (ibe->ibe_argv0_cnt != 0) {
656 if (imgp->args->fname != NULL) {
657 fname = imgp->args->fname;
659 /* Use the fdescfs(5) path for fexecve(2). */
660 sname = sbuf_new_auto();
661 sbuf_printf(sname, "/dev/fd/%d", imgp->args->fd);
663 fname = sbuf_data(sname);
666 namelen = strlen(fname);
670 * We need to "push" the interpreter in the arg[] list. To do this,
671 * we first shift all the other values in the `begin_argv' area to
672 * provide the exact amount of room for the values added. Set up
673 * `offset' as the number of bytes to be added to the `begin_argv'
674 * area. ibe_interp_offset is the fixed offset from macros present in
675 * the interpreter string.
677 offset = ibe->ibe_interp_length + ibe->ibe_interp_offset;
679 /* Variable offset to be added from macros to the interpreter string. */
680 MPASS(ibe->ibe_argv0_cnt == 0 || namelen > 0);
681 offset += ibe->ibe_argv0_cnt * (namelen - 2);
683 /* Make room for the interpreter */
684 error = exec_args_adjust_args(imgp->args, 0, offset);
689 /* Add the new argument(s) in the count. */
690 imgp->args->argc += ibe->ibe_interp_argcnt;
693 * The original arg[] list has been shifted appropriately. Copy in
694 * the interpreter path.
696 s = ibe->ibe_interpreter;
697 d = imgp->args->begin_argv;
701 /* Handle "#" in interpreter string. */
705 /* "##": Replace with a single '#' */
709 /* "#a": Replace with old arg0 (fname). */
710 MPASS(ibe->ibe_argv0_cnt >= ++argv0_cnt);
711 memcpy(d, fname, namelen);
715 __assert_unreachable();
719 /* Replace space with NUL to separate arguments. */
730 /* Catch ibe->ibe_argv0_cnt counting more #a than we did. */
731 MPASS(ibe->ibe_argv0_cnt == argv0_cnt);
732 imgp->interpreter_name = imgp->args->begin_argv;
733 if (ibe->ibe_interpreter_vnode) {
734 imgp->interpreter_vp = ibe->ibe_interpreter_vnode;
735 vref(imgp->interpreter_vp);
739 INTERP_LIST_RUNLOCK();
746 imgact_binmisc_init(void *arg)
749 INTERP_LIST_LOCK_INIT();
753 imgact_binmisc_fini(void *arg)
755 imgact_binmisc_entry_t *ibe, *ibe_tmp;
757 /* Free all the interpreters. */
759 SLIST_FOREACH_SAFE(ibe, &interpreter_list, link, ibe_tmp) {
760 SLIST_REMOVE(&interpreter_list, ibe, imgact_binmisc_entry,
762 imgact_binmisc_destroy_entry(ibe);
764 INTERP_LIST_WUNLOCK();
766 INTERP_LIST_LOCK_DESTROY();
769 SYSINIT(imgact_binmisc, SI_SUB_EXEC, SI_ORDER_MIDDLE, imgact_binmisc_init,
771 SYSUNINIT(imgact_binmisc, SI_SUB_EXEC, SI_ORDER_MIDDLE, imgact_binmisc_fini,
775 * Tell kern_execve.c about it, with a little help from the linker.
777 static struct execsw imgact_binmisc_execsw = {
778 .ex_imgact = imgact_binmisc_exec,
781 EXEC_SET(imgact_binmisc, imgact_binmisc_execsw);