Commit | Line | Data |
---|---|---|
09c434b8 | 1 | // SPDX-License-Identifier: GPL-2.0-only |
1da177e4 | 2 | /* |
e6084d4a | 3 | * binfmt_misc.c |
1da177e4 | 4 | * |
e6084d4a | 5 | * Copyright (C) 1997 Richard Günther |
1da177e4 | 6 | * |
e6084d4a | 7 | * binfmt_misc detects binaries via a magic or filename extension and invokes |
34962fb8 | 8 | * a specified wrapper. See Documentation/admin-guide/binfmt-misc.rst for more details. |
1da177e4 LT |
9 | */ |
10 | ||
6b899c4e MF |
11 | #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt |
12 | ||
6ceafb88 | 13 | #include <linux/kernel.h> |
1da177e4 LT |
14 | #include <linux/module.h> |
15 | #include <linux/init.h> | |
589ee628 | 16 | #include <linux/sched/mm.h> |
b502bd11 | 17 | #include <linux/magic.h> |
1da177e4 LT |
18 | #include <linux/binfmts.h> |
19 | #include <linux/slab.h> | |
20 | #include <linux/ctype.h> | |
8d82e180 | 21 | #include <linux/string_helpers.h> |
1da177e4 LT |
22 | #include <linux/file.h> |
23 | #include <linux/pagemap.h> | |
24 | #include <linux/namei.h> | |
25 | #include <linux/mount.h> | |
bc99a664 | 26 | #include <linux/fs_context.h> |
1da177e4 | 27 | #include <linux/syscalls.h> |
6e2c10a1 | 28 | #include <linux/fs.h> |
6b899c4e | 29 | #include <linux/uaccess.h> |
1da177e4 | 30 | |
948b701a JB |
31 | #include "internal.h" |
32 | ||
6b899c4e MF |
33 | #ifdef DEBUG |
34 | # define USE_DEBUG 1 | |
35 | #else | |
36 | # define USE_DEBUG 0 | |
37 | #endif | |
1da177e4 LT |
38 | |
39 | enum { | |
40 | VERBOSE_STATUS = 1 /* make it zero to save 400 bytes kernel memory */ | |
41 | }; | |
42 | ||
1da177e4 | 43 | enum {Enabled, Magic}; |
6a46bf55 LS |
44 | #define MISC_FMT_PRESERVE_ARGV0 (1UL << 31) |
45 | #define MISC_FMT_OPEN_BINARY (1UL << 30) | |
46 | #define MISC_FMT_CREDENTIALS (1UL << 29) | |
47 | #define MISC_FMT_OPEN_FILE (1UL << 28) | |
1da177e4 LT |
48 | |
49 | typedef struct { | |
50 | struct list_head list; | |
51 | unsigned long flags; /* type, status, etc. */ | |
52 | int offset; /* offset of magic */ | |
53 | int size; /* size of magic/mask */ | |
54 | char *magic; /* magic or filename extension */ | |
55 | char *mask; /* mask, NULL for exact match */ | |
50097f74 | 56 | const char *interpreter; /* filename of interpreter */ |
1da177e4 LT |
57 | char *name; |
58 | struct dentry *dentry; | |
948b701a | 59 | struct file *interp_file; |
1c5976ef | 60 | refcount_t users; /* sync removal with load_misc_binary() */ |
1da177e4 LT |
61 | } Node; |
62 | ||
1f5ce9e9 | 63 | static struct file_system_type bm_fs_type; |
1da177e4 | 64 | |
bbaecc08 MF |
65 | /* |
66 | * Max length of the register string. Determined by: | |
67 | * - 7 delimiters | |
68 | * - name: ~50 bytes | |
69 | * - type: 1 byte | |
70 | * - offset: 3 bytes (has to be smaller than BINPRM_BUF_SIZE) | |
71 | * - magic: 128 bytes (512 in escaped form) | |
72 | * - mask: 128 bytes (512 in escaped form) | |
73 | * - interp: ~50 bytes | |
74 | * - flags: 5 bytes | |
75 | * Round that up a bit, and then back off to hold the internal data | |
76 | * (like struct Node). | |
77 | */ | |
78 | #define MAX_REGISTER_LENGTH 1920 | |
79 | ||
1c5976ef CB |
80 | /** |
81 | * search_binfmt_handler - search for a binary handler for @bprm | |
82 | * @misc: handle to binfmt_misc instance | |
83 | * @bprm: binary for which we are looking for a handler | |
84 | * | |
85 | * Search for a binary type handler for @bprm in the list of registered binary | |
86 | * type handlers. | |
87 | * | |
88 | * Return: binary type list entry on success, NULL on failure | |
1da177e4 | 89 | */ |
21ca59b3 CB |
90 | static Node *search_binfmt_handler(struct binfmt_misc *misc, |
91 | struct linux_binprm *bprm) | |
1da177e4 LT |
92 | { |
93 | char *p = strrchr(bprm->interp, '.'); | |
1c5976ef | 94 | Node *e; |
1da177e4 | 95 | |
6b899c4e | 96 | /* Walk all the registered handlers. */ |
21ca59b3 | 97 | list_for_each_entry(e, &misc->entries, list) { |
1da177e4 LT |
98 | char *s; |
99 | int j; | |
100 | ||
6b899c4e | 101 | /* Make sure this one is currently enabled. */ |
1da177e4 LT |
102 | if (!test_bit(Enabled, &e->flags)) |
103 | continue; | |
104 | ||
6b899c4e | 105 | /* Do matching based on extension if applicable. */ |
1da177e4 LT |
106 | if (!test_bit(Magic, &e->flags)) { |
107 | if (p && !strcmp(e->magic, p + 1)) | |
108 | return e; | |
109 | continue; | |
110 | } | |
111 | ||
6b899c4e | 112 | /* Do matching based on magic & mask. */ |
1da177e4 LT |
113 | s = bprm->buf + e->offset; |
114 | if (e->mask) { | |
115 | for (j = 0; j < e->size; j++) | |
116 | if ((*s++ ^ e->magic[j]) & e->mask[j]) | |
117 | break; | |
118 | } else { | |
119 | for (j = 0; j < e->size; j++) | |
120 | if ((*s++ ^ e->magic[j])) | |
121 | break; | |
122 | } | |
123 | if (j == e->size) | |
124 | return e; | |
125 | } | |
1c5976ef | 126 | |
1da177e4 LT |
127 | return NULL; |
128 | } | |
129 | ||
1c5976ef CB |
130 | /** |
131 | * get_binfmt_handler - try to find a binary type handler | |
132 | * @misc: handle to binfmt_misc instance | |
133 | * @bprm: binary for which we are looking for a handler | |
134 | * | |
135 | * Try to find a binfmt handler for the binary type. If one is found take a | |
136 | * reference to protect against removal via bm_{entry,status}_write(). | |
137 | * | |
138 | * Return: binary type list entry on success, NULL on failure | |
139 | */ | |
21ca59b3 CB |
140 | static Node *get_binfmt_handler(struct binfmt_misc *misc, |
141 | struct linux_binprm *bprm) | |
1c5976ef CB |
142 | { |
143 | Node *e; | |
144 | ||
21ca59b3 CB |
145 | read_lock(&misc->entries_lock); |
146 | e = search_binfmt_handler(misc, bprm); | |
1c5976ef CB |
147 | if (e) |
148 | refcount_inc(&e->users); | |
21ca59b3 | 149 | read_unlock(&misc->entries_lock); |
1c5976ef CB |
150 | return e; |
151 | } | |
152 | ||
153 | /** | |
154 | * put_binfmt_handler - put binary handler node | |
155 | * @e: node to put | |
156 | * | |
157 | * Free node syncing with load_misc_binary() and defer final free to | |
158 | * load_misc_binary() in case it is using the binary type handler we were | |
159 | * requested to remove. | |
160 | */ | |
161 | static void put_binfmt_handler(Node *e) | |
162 | { | |
163 | if (refcount_dec_and_test(&e->users)) { | |
164 | if (e->flags & MISC_FMT_OPEN_FILE) | |
165 | filp_close(e->interp_file, NULL); | |
166 | kfree(e); | |
167 | } | |
168 | } | |
169 | ||
21ca59b3 CB |
170 | /** |
171 | * load_binfmt_misc - load the binfmt_misc of the caller's user namespace | |
172 | * | |
173 | * To be called in load_misc_binary() to load the relevant struct binfmt_misc. | |
174 | * If a user namespace doesn't have its own binfmt_misc mount it can make use | |
175 | * of its ancestor's binfmt_misc handlers. This mimicks the behavior of | |
176 | * pre-namespaced binfmt_misc where all registered binfmt_misc handlers where | |
177 | * available to all user and user namespaces on the system. | |
178 | * | |
179 | * Return: the binfmt_misc instance of the caller's user namespace | |
180 | */ | |
181 | static struct binfmt_misc *load_binfmt_misc(void) | |
182 | { | |
183 | const struct user_namespace *user_ns; | |
184 | struct binfmt_misc *misc; | |
185 | ||
186 | user_ns = current_user_ns(); | |
187 | while (user_ns) { | |
188 | /* Pairs with smp_store_release() in bm_fill_super(). */ | |
189 | misc = smp_load_acquire(&user_ns->binfmt_misc); | |
190 | if (misc) | |
191 | return misc; | |
192 | ||
193 | user_ns = user_ns->parent; | |
194 | } | |
195 | ||
196 | return &init_binfmt_misc; | |
197 | } | |
198 | ||
1da177e4 LT |
199 | /* |
200 | * the loader itself | |
201 | */ | |
71613c3b | 202 | static int load_misc_binary(struct linux_binprm *bprm) |
1da177e4 LT |
203 | { |
204 | Node *fmt; | |
e6084d4a | 205 | struct file *interp_file = NULL; |
21ca59b3 CB |
206 | int retval = -ENOEXEC; |
207 | struct binfmt_misc *misc; | |
1da177e4 | 208 | |
21ca59b3 CB |
209 | misc = load_binfmt_misc(); |
210 | if (!misc->enabled) | |
43a4f261 | 211 | return retval; |
1da177e4 | 212 | |
21ca59b3 | 213 | fmt = get_binfmt_handler(misc, bprm); |
1da177e4 | 214 | if (!fmt) |
43a4f261 | 215 | return retval; |
1da177e4 | 216 | |
51f39a1f | 217 | /* Need to be able to load the file after exec */ |
43a4f261 | 218 | retval = -ENOENT; |
51f39a1f | 219 | if (bprm->interp_flags & BINPRM_FLAGS_PATH_INACCESSIBLE) |
43a4f261 | 220 | goto ret; |
51f39a1f | 221 | |
2347961b LV |
222 | if (fmt->flags & MISC_FMT_PRESERVE_ARGV0) { |
223 | bprm->interp_flags |= BINPRM_FLAGS_PRESERVE_ARGV0; | |
224 | } else { | |
b6a2fea3 OW |
225 | retval = remove_arg_zero(bprm); |
226 | if (retval) | |
e6084d4a | 227 | goto ret; |
1da177e4 LT |
228 | } |
229 | ||
bc2bf338 | 230 | if (fmt->flags & MISC_FMT_OPEN_BINARY) |
b8a61c9e | 231 | bprm->have_execfd = 1; |
1da177e4 | 232 | |
1da177e4 | 233 | /* make argv[1] be the path to the binary */ |
986db2d1 | 234 | retval = copy_string_kernel(bprm->interp, bprm); |
1da177e4 | 235 | if (retval < 0) |
b8a61c9e | 236 | goto ret; |
1da177e4 LT |
237 | bprm->argc++; |
238 | ||
239 | /* add the interp as argv[0] */ | |
986db2d1 | 240 | retval = copy_string_kernel(fmt->interpreter, bprm); |
1da177e4 | 241 | if (retval < 0) |
b8a61c9e | 242 | goto ret; |
e6084d4a | 243 | bprm->argc++; |
1da177e4 | 244 | |
b66c5984 | 245 | /* Update interp in case binfmt_script needs it. */ |
50097f74 | 246 | retval = bprm_change_interp(fmt->interpreter, bprm); |
b66c5984 | 247 | if (retval < 0) |
b8a61c9e | 248 | goto ret; |
1da177e4 | 249 | |
2a010c41 | 250 | if (fmt->flags & MISC_FMT_OPEN_FILE) |
19f391eb | 251 | interp_file = file_clone_open(fmt->interp_file); |
2a010c41 | 252 | else |
50097f74 | 253 | interp_file = open_exec(fmt->interpreter); |
e6084d4a MF |
254 | retval = PTR_ERR(interp_file); |
255 | if (IS_ERR(interp_file)) | |
b8a61c9e | 256 | goto ret; |
1da177e4 | 257 | |
bc2bf338 | 258 | bprm->interpreter = interp_file; |
a16b3357 | 259 | if (fmt->flags & MISC_FMT_CREDENTIALS) |
56305aa9 | 260 | bprm->execfd_creds = 1; |
1da177e4 | 261 | |
bc2bf338 | 262 | retval = 0; |
e6084d4a | 263 | ret: |
1c5976ef CB |
264 | |
265 | /* | |
266 | * If we actually put the node here all concurrent calls to | |
267 | * load_misc_binary() will have finished. We also know | |
21ca59b3 CB |
268 | * that for the refcount to be zero someone must have concurently |
269 | * removed the binary type handler from the list and it's our job to | |
270 | * free it. | |
1c5976ef CB |
271 | */ |
272 | put_binfmt_handler(fmt); | |
273 | ||
1da177e4 | 274 | return retval; |
1da177e4 LT |
275 | } |
276 | ||
277 | /* Command parsers */ | |
278 | ||
279 | /* | |
280 | * parses and copies one argument enclosed in del from *sp to *dp, | |
281 | * recognising the \x special. | |
282 | * returns pointer to the copied argument or NULL in case of an | |
283 | * error (and sets err) or null argument length. | |
284 | */ | |
285 | static char *scanarg(char *s, char del) | |
286 | { | |
287 | char c; | |
288 | ||
289 | while ((c = *s++) != del) { | |
290 | if (c == '\\' && *s == 'x') { | |
291 | s++; | |
292 | if (!isxdigit(*s++)) | |
293 | return NULL; | |
294 | if (!isxdigit(*s++)) | |
295 | return NULL; | |
296 | } | |
297 | } | |
7d65cf10 | 298 | s[-1] ='\0'; |
1da177e4 LT |
299 | return s; |
300 | } | |
301 | ||
e6084d4a | 302 | static char *check_special_flags(char *sfs, Node *e) |
1da177e4 | 303 | { |
e6084d4a | 304 | char *p = sfs; |
1da177e4 LT |
305 | int cont = 1; |
306 | ||
307 | /* special flags */ | |
308 | while (cont) { | |
309 | switch (*p) { | |
e6084d4a MF |
310 | case 'P': |
311 | pr_debug("register: flag: P (preserve argv0)\n"); | |
312 | p++; | |
313 | e->flags |= MISC_FMT_PRESERVE_ARGV0; | |
314 | break; | |
315 | case 'O': | |
316 | pr_debug("register: flag: O (open binary)\n"); | |
317 | p++; | |
318 | e->flags |= MISC_FMT_OPEN_BINARY; | |
319 | break; | |
320 | case 'C': | |
321 | pr_debug("register: flag: C (preserve creds)\n"); | |
322 | p++; | |
323 | /* this flags also implies the | |
324 | open-binary flag */ | |
325 | e->flags |= (MISC_FMT_CREDENTIALS | | |
326 | MISC_FMT_OPEN_BINARY); | |
327 | break; | |
948b701a JB |
328 | case 'F': |
329 | pr_debug("register: flag: F: open interpreter file now\n"); | |
330 | p++; | |
331 | e->flags |= MISC_FMT_OPEN_FILE; | |
332 | break; | |
e6084d4a MF |
333 | default: |
334 | cont = 0; | |
1da177e4 LT |
335 | } |
336 | } | |
337 | ||
338 | return p; | |
339 | } | |
e6084d4a | 340 | |
1da177e4 LT |
341 | /* |
342 | * This registers a new binary format, it recognises the syntax | |
343 | * ':name:type:offset:magic:mask:interpreter:flags' | |
344 | * where the ':' is the IFS, that can be chosen with the first char | |
345 | */ | |
346 | static Node *create_entry(const char __user *buffer, size_t count) | |
347 | { | |
348 | Node *e; | |
349 | int memsize, err; | |
350 | char *buf, *p; | |
351 | char del; | |
352 | ||
6b899c4e MF |
353 | pr_debug("register: received %zu bytes\n", count); |
354 | ||
1da177e4 LT |
355 | /* some sanity checks */ |
356 | err = -EINVAL; | |
bbaecc08 | 357 | if ((count < 11) || (count > MAX_REGISTER_LENGTH)) |
1da177e4 LT |
358 | goto out; |
359 | ||
360 | err = -ENOMEM; | |
361 | memsize = sizeof(Node) + count + 8; | |
21ca59b3 | 362 | e = kmalloc(memsize, GFP_KERNEL_ACCOUNT); |
1da177e4 LT |
363 | if (!e) |
364 | goto out; | |
365 | ||
366 | p = buf = (char *)e + sizeof(Node); | |
367 | ||
368 | memset(e, 0, sizeof(Node)); | |
369 | if (copy_from_user(buf, buffer, count)) | |
e6084d4a | 370 | goto efault; |
1da177e4 LT |
371 | |
372 | del = *p++; /* delimeter */ | |
373 | ||
6b899c4e MF |
374 | pr_debug("register: delim: %#x {%c}\n", del, del); |
375 | ||
376 | /* Pad the buffer with the delim to simplify parsing below. */ | |
e6084d4a | 377 | memset(buf + count, del, 8); |
1da177e4 | 378 | |
6b899c4e | 379 | /* Parse the 'name' field. */ |
1da177e4 LT |
380 | e->name = p; |
381 | p = strchr(p, del); | |
382 | if (!p) | |
e6084d4a | 383 | goto einval; |
1da177e4 LT |
384 | *p++ = '\0'; |
385 | if (!e->name[0] || | |
386 | !strcmp(e->name, ".") || | |
387 | !strcmp(e->name, "..") || | |
388 | strchr(e->name, '/')) | |
e6084d4a | 389 | goto einval; |
6b899c4e MF |
390 | |
391 | pr_debug("register: name: {%s}\n", e->name); | |
392 | ||
393 | /* Parse the 'type' field. */ | |
1da177e4 | 394 | switch (*p++) { |
6b899c4e MF |
395 | case 'E': |
396 | pr_debug("register: type: E (extension)\n"); | |
397 | e->flags = 1 << Enabled; | |
398 | break; | |
399 | case 'M': | |
400 | pr_debug("register: type: M (magic)\n"); | |
401 | e->flags = (1 << Enabled) | (1 << Magic); | |
402 | break; | |
403 | default: | |
e6084d4a | 404 | goto einval; |
1da177e4 LT |
405 | } |
406 | if (*p++ != del) | |
e6084d4a | 407 | goto einval; |
6b899c4e | 408 | |
1da177e4 | 409 | if (test_bit(Magic, &e->flags)) { |
6b899c4e MF |
410 | /* Handle the 'M' (magic) format. */ |
411 | char *s; | |
412 | ||
413 | /* Parse the 'offset' field. */ | |
414 | s = strchr(p, del); | |
1da177e4 | 415 | if (!s) |
e6084d4a | 416 | goto einval; |
5cc41e09 TLSC |
417 | *s = '\0'; |
418 | if (p != s) { | |
419 | int r = kstrtoint(p, 10, &e->offset); | |
420 | if (r != 0 || e->offset < 0) | |
421 | goto einval; | |
422 | } | |
423 | p = s; | |
1da177e4 | 424 | if (*p++) |
e6084d4a | 425 | goto einval; |
6b899c4e MF |
426 | pr_debug("register: offset: %#x\n", e->offset); |
427 | ||
428 | /* Parse the 'magic' field. */ | |
1da177e4 LT |
429 | e->magic = p; |
430 | p = scanarg(p, del); | |
431 | if (!p) | |
e6084d4a | 432 | goto einval; |
7d65cf10 | 433 | if (!e->magic[0]) |
e6084d4a | 434 | goto einval; |
6b899c4e MF |
435 | if (USE_DEBUG) |
436 | print_hex_dump_bytes( | |
437 | KBUILD_MODNAME ": register: magic[raw]: ", | |
438 | DUMP_PREFIX_NONE, e->magic, p - e->magic); | |
439 | ||
440 | /* Parse the 'mask' field. */ | |
1da177e4 LT |
441 | e->mask = p; |
442 | p = scanarg(p, del); | |
443 | if (!p) | |
e6084d4a | 444 | goto einval; |
7d65cf10 | 445 | if (!e->mask[0]) { |
1da177e4 | 446 | e->mask = NULL; |
6b899c4e MF |
447 | pr_debug("register: mask[raw]: none\n"); |
448 | } else if (USE_DEBUG) | |
449 | print_hex_dump_bytes( | |
450 | KBUILD_MODNAME ": register: mask[raw]: ", | |
451 | DUMP_PREFIX_NONE, e->mask, p - e->mask); | |
452 | ||
453 | /* | |
454 | * Decode the magic & mask fields. | |
455 | * Note: while we might have accepted embedded NUL bytes from | |
456 | * above, the unescape helpers here will stop at the first one | |
457 | * it encounters. | |
458 | */ | |
8d82e180 AS |
459 | e->size = string_unescape_inplace(e->magic, UNESCAPE_HEX); |
460 | if (e->mask && | |
461 | string_unescape_inplace(e->mask, UNESCAPE_HEX) != e->size) | |
e6084d4a | 462 | goto einval; |
5cc41e09 TLSC |
463 | if (e->size > BINPRM_BUF_SIZE || |
464 | BINPRM_BUF_SIZE - e->size < e->offset) | |
e6084d4a | 465 | goto einval; |
6b899c4e MF |
466 | pr_debug("register: magic/mask length: %i\n", e->size); |
467 | if (USE_DEBUG) { | |
468 | print_hex_dump_bytes( | |
469 | KBUILD_MODNAME ": register: magic[decoded]: ", | |
470 | DUMP_PREFIX_NONE, e->magic, e->size); | |
471 | ||
472 | if (e->mask) { | |
473 | int i; | |
21ca59b3 | 474 | char *masked = kmalloc(e->size, GFP_KERNEL_ACCOUNT); |
6b899c4e MF |
475 | |
476 | print_hex_dump_bytes( | |
477 | KBUILD_MODNAME ": register: mask[decoded]: ", | |
478 | DUMP_PREFIX_NONE, e->mask, e->size); | |
479 | ||
480 | if (masked) { | |
481 | for (i = 0; i < e->size; ++i) | |
482 | masked[i] = e->magic[i] & e->mask[i]; | |
483 | print_hex_dump_bytes( | |
484 | KBUILD_MODNAME ": register: magic[masked]: ", | |
485 | DUMP_PREFIX_NONE, masked, e->size); | |
486 | ||
487 | kfree(masked); | |
488 | } | |
489 | } | |
490 | } | |
1da177e4 | 491 | } else { |
6b899c4e MF |
492 | /* Handle the 'E' (extension) format. */ |
493 | ||
494 | /* Skip the 'offset' field. */ | |
1da177e4 LT |
495 | p = strchr(p, del); |
496 | if (!p) | |
e6084d4a | 497 | goto einval; |
1da177e4 | 498 | *p++ = '\0'; |
6b899c4e MF |
499 | |
500 | /* Parse the 'magic' field. */ | |
1da177e4 LT |
501 | e->magic = p; |
502 | p = strchr(p, del); | |
503 | if (!p) | |
e6084d4a | 504 | goto einval; |
1da177e4 LT |
505 | *p++ = '\0'; |
506 | if (!e->magic[0] || strchr(e->magic, '/')) | |
e6084d4a | 507 | goto einval; |
6b899c4e MF |
508 | pr_debug("register: extension: {%s}\n", e->magic); |
509 | ||
510 | /* Skip the 'mask' field. */ | |
1da177e4 LT |
511 | p = strchr(p, del); |
512 | if (!p) | |
e6084d4a | 513 | goto einval; |
1da177e4 LT |
514 | *p++ = '\0'; |
515 | } | |
6b899c4e MF |
516 | |
517 | /* Parse the 'interpreter' field. */ | |
1da177e4 LT |
518 | e->interpreter = p; |
519 | p = strchr(p, del); | |
520 | if (!p) | |
e6084d4a | 521 | goto einval; |
1da177e4 LT |
522 | *p++ = '\0'; |
523 | if (!e->interpreter[0]) | |
e6084d4a | 524 | goto einval; |
6b899c4e | 525 | pr_debug("register: interpreter: {%s}\n", e->interpreter); |
1da177e4 | 526 | |
6b899c4e | 527 | /* Parse the 'flags' field. */ |
e6084d4a | 528 | p = check_special_flags(p, e); |
1da177e4 LT |
529 | if (*p == '\n') |
530 | p++; | |
531 | if (p != buf + count) | |
e6084d4a MF |
532 | goto einval; |
533 | ||
1da177e4 LT |
534 | return e; |
535 | ||
536 | out: | |
537 | return ERR_PTR(err); | |
538 | ||
e6084d4a | 539 | efault: |
1da177e4 LT |
540 | kfree(e); |
541 | return ERR_PTR(-EFAULT); | |
e6084d4a | 542 | einval: |
1da177e4 LT |
543 | kfree(e); |
544 | return ERR_PTR(-EINVAL); | |
545 | } | |
546 | ||
547 | /* | |
548 | * Set status of entry/binfmt_misc: | |
549 | * '1' enables, '0' disables and '-1' clears entry/binfmt_misc | |
550 | */ | |
551 | static int parse_command(const char __user *buffer, size_t count) | |
552 | { | |
553 | char s[4]; | |
554 | ||
1da177e4 LT |
555 | if (count > 3) |
556 | return -EINVAL; | |
557 | if (copy_from_user(s, buffer, count)) | |
558 | return -EFAULT; | |
de8288b1 AB |
559 | if (!count) |
560 | return 0; | |
e6084d4a | 561 | if (s[count - 1] == '\n') |
1da177e4 LT |
562 | count--; |
563 | if (count == 1 && s[0] == '0') | |
564 | return 1; | |
565 | if (count == 1 && s[0] == '1') | |
566 | return 2; | |
567 | if (count == 2 && s[0] == '-' && s[1] == '1') | |
568 | return 3; | |
569 | return -EINVAL; | |
570 | } | |
571 | ||
572 | /* generic stuff */ | |
573 | ||
574 | static void entry_status(Node *e, char *page) | |
575 | { | |
6ceafb88 RV |
576 | char *dp = page; |
577 | const char *status = "disabled"; | |
1da177e4 LT |
578 | |
579 | if (test_bit(Enabled, &e->flags)) | |
580 | status = "enabled"; | |
581 | ||
582 | if (!VERBOSE_STATUS) { | |
583 | sprintf(page, "%s\n", status); | |
584 | return; | |
585 | } | |
586 | ||
6ceafb88 | 587 | dp += sprintf(dp, "%s\ninterpreter %s\n", status, e->interpreter); |
1da177e4 LT |
588 | |
589 | /* print the special flags */ | |
6ceafb88 | 590 | dp += sprintf(dp, "flags: "); |
e6084d4a MF |
591 | if (e->flags & MISC_FMT_PRESERVE_ARGV0) |
592 | *dp++ = 'P'; | |
593 | if (e->flags & MISC_FMT_OPEN_BINARY) | |
594 | *dp++ = 'O'; | |
595 | if (e->flags & MISC_FMT_CREDENTIALS) | |
596 | *dp++ = 'C'; | |
948b701a JB |
597 | if (e->flags & MISC_FMT_OPEN_FILE) |
598 | *dp++ = 'F'; | |
e6084d4a | 599 | *dp++ = '\n'; |
1da177e4 LT |
600 | |
601 | if (!test_bit(Magic, &e->flags)) { | |
602 | sprintf(dp, "extension .%s\n", e->magic); | |
603 | } else { | |
6ceafb88 RV |
604 | dp += sprintf(dp, "offset %i\nmagic ", e->offset); |
605 | dp = bin2hex(dp, e->magic, e->size); | |
1da177e4 | 606 | if (e->mask) { |
6ceafb88 RV |
607 | dp += sprintf(dp, "\nmask "); |
608 | dp = bin2hex(dp, e->mask, e->size); | |
1da177e4 LT |
609 | } |
610 | *dp++ = '\n'; | |
611 | *dp = '\0'; | |
612 | } | |
613 | } | |
614 | ||
615 | static struct inode *bm_get_inode(struct super_block *sb, int mode) | |
616 | { | |
e6084d4a | 617 | struct inode *inode = new_inode(sb); |
1da177e4 LT |
618 | |
619 | if (inode) { | |
85fe4025 | 620 | inode->i_ino = get_next_ino(); |
1da177e4 | 621 | inode->i_mode = mode; |
16a94965 | 622 | simple_inode_init_ts(inode); |
1da177e4 LT |
623 | } |
624 | return inode; | |
625 | } | |
626 | ||
21ca59b3 CB |
627 | /** |
628 | * i_binfmt_misc - retrieve struct binfmt_misc from a binfmt_misc inode | |
629 | * @inode: inode of the relevant binfmt_misc instance | |
630 | * | |
631 | * This helper retrieves struct binfmt_misc from a binfmt_misc inode. This can | |
632 | * be done without any memory barriers because we are guaranteed that | |
633 | * user_ns->binfmt_misc is fully initialized. It was fully initialized when the | |
634 | * binfmt_misc mount was first created. | |
635 | * | |
636 | * Return: struct binfmt_misc of the relevant binfmt_misc instance | |
637 | */ | |
638 | static struct binfmt_misc *i_binfmt_misc(struct inode *inode) | |
639 | { | |
640 | return inode->i_sb->s_user_ns->binfmt_misc; | |
641 | } | |
642 | ||
1c5976ef CB |
643 | /** |
644 | * bm_evict_inode - cleanup data associated with @inode | |
645 | * @inode: inode to which the data is attached | |
646 | * | |
647 | * Cleanup the binary type handler data associated with @inode if a binary type | |
648 | * entry is removed or the filesystem is unmounted and the super block is | |
649 | * shutdown. | |
650 | * | |
651 | * If the ->evict call was not caused by a super block shutdown but by a write | |
652 | * to remove the entry or all entries via bm_{entry,status}_write() the entry | |
653 | * will have already been removed from the list. We keep the list_empty() check | |
654 | * to make that explicit. | |
655 | */ | |
b57922d9 | 656 | static void bm_evict_inode(struct inode *inode) |
1da177e4 | 657 | { |
83f91827 ON |
658 | Node *e = inode->i_private; |
659 | ||
dbd5768f | 660 | clear_inode(inode); |
1c5976ef CB |
661 | |
662 | if (e) { | |
21ca59b3 CB |
663 | struct binfmt_misc *misc; |
664 | ||
665 | misc = i_binfmt_misc(inode); | |
666 | write_lock(&misc->entries_lock); | |
1c5976ef CB |
667 | if (!list_empty(&e->list)) |
668 | list_del_init(&e->list); | |
21ca59b3 | 669 | write_unlock(&misc->entries_lock); |
1c5976ef CB |
670 | put_binfmt_handler(e); |
671 | } | |
1da177e4 LT |
672 | } |
673 | ||
1c5976ef CB |
674 | /** |
675 | * unlink_binfmt_dentry - remove the dentry for the binary type handler | |
676 | * @dentry: dentry associated with the binary type handler | |
677 | * | |
678 | * Do the actual filesystem work to remove a dentry for a registered binary | |
679 | * type handler. Since binfmt_misc only allows simple files to be created | |
680 | * directly under the root dentry of the filesystem we ensure that we are | |
681 | * indeed passed a dentry directly beneath the root dentry, that the inode | |
682 | * associated with the root dentry is locked, and that it is a regular file we | |
683 | * are asked to remove. | |
684 | */ | |
685 | static void unlink_binfmt_dentry(struct dentry *dentry) | |
1da177e4 | 686 | { |
1c5976ef CB |
687 | struct dentry *parent = dentry->d_parent; |
688 | struct inode *inode, *parent_inode; | |
1da177e4 | 689 | |
1c5976ef CB |
690 | /* All entries are immediate descendants of the root dentry. */ |
691 | if (WARN_ON_ONCE(dentry->d_sb->s_root != parent)) | |
692 | return; | |
1da177e4 | 693 | |
1c5976ef CB |
694 | /* We only expect to be called on regular files. */ |
695 | inode = d_inode(dentry); | |
696 | if (WARN_ON_ONCE(!S_ISREG(inode->i_mode))) | |
697 | return; | |
698 | ||
699 | /* The parent inode must be locked. */ | |
700 | parent_inode = d_inode(parent); | |
701 | if (WARN_ON_ONCE(!inode_is_locked(parent_inode))) | |
702 | return; | |
703 | ||
704 | if (simple_positive(dentry)) { | |
705 | dget(dentry); | |
706 | simple_unlink(parent_inode, dentry); | |
707 | d_delete(dentry); | |
708 | dput(dentry); | |
709 | } | |
710 | } | |
711 | ||
712 | /** | |
713 | * remove_binfmt_handler - remove a binary type handler | |
714 | * @misc: handle to binfmt_misc instance | |
715 | * @e: binary type handler to remove | |
716 | * | |
717 | * Remove a binary type handler from the list of binary type handlers and | |
718 | * remove its associated dentry. This is called from | |
719 | * binfmt_{entry,status}_write(). In the future, we might want to think about | |
720 | * adding a proper ->unlink() method to binfmt_misc instead of forcing caller's | |
721 | * to use writes to files in order to delete binary type handlers. But it has | |
722 | * worked for so long that it's not a pressing issue. | |
723 | */ | |
21ca59b3 | 724 | static void remove_binfmt_handler(struct binfmt_misc *misc, Node *e) |
1c5976ef | 725 | { |
21ca59b3 | 726 | write_lock(&misc->entries_lock); |
baba1b29 | 727 | list_del_init(&e->list); |
21ca59b3 | 728 | write_unlock(&misc->entries_lock); |
1c5976ef | 729 | unlink_binfmt_dentry(e->dentry); |
1da177e4 LT |
730 | } |
731 | ||
732 | /* /<entry> */ | |
733 | ||
734 | static ssize_t | |
e6084d4a | 735 | bm_entry_read(struct file *file, char __user *buf, size_t nbytes, loff_t *ppos) |
1da177e4 | 736 | { |
496ad9aa | 737 | Node *e = file_inode(file)->i_private; |
1da177e4 LT |
738 | ssize_t res; |
739 | char *page; | |
1da177e4 | 740 | |
e6084d4a MF |
741 | page = (char *) __get_free_page(GFP_KERNEL); |
742 | if (!page) | |
1da177e4 LT |
743 | return -ENOMEM; |
744 | ||
745 | entry_status(e, page); | |
1da177e4 | 746 | |
6e2c10a1 AM |
747 | res = simple_read_from_buffer(buf, nbytes, ppos, page, strlen(page)); |
748 | ||
1da177e4 LT |
749 | free_page((unsigned long) page); |
750 | return res; | |
751 | } | |
752 | ||
753 | static ssize_t bm_entry_write(struct file *file, const char __user *buffer, | |
754 | size_t count, loff_t *ppos) | |
755 | { | |
1c5976ef CB |
756 | struct inode *inode = file_inode(file); |
757 | Node *e = inode->i_private; | |
1da177e4 LT |
758 | int res = parse_command(buffer, count); |
759 | ||
760 | switch (res) { | |
e6084d4a MF |
761 | case 1: |
762 | /* Disable this handler. */ | |
763 | clear_bit(Enabled, &e->flags); | |
764 | break; | |
765 | case 2: | |
766 | /* Enable this handler. */ | |
767 | set_bit(Enabled, &e->flags); | |
768 | break; | |
769 | case 3: | |
770 | /* Delete this handler. */ | |
1c5976ef CB |
771 | inode = d_inode(inode->i_sb->s_root); |
772 | inode_lock(inode); | |
1da177e4 | 773 | |
1c5976ef CB |
774 | /* |
775 | * In order to add new element or remove elements from the list | |
776 | * via bm_{entry,register,status}_write() inode_lock() on the | |
777 | * root inode must be held. | |
778 | * The lock is exclusive ensuring that the list can't be | |
779 | * modified. Only load_misc_binary() can access but does so | |
780 | * read-only. So we only need to take the write lock when we | |
781 | * actually remove the entry from the list. | |
782 | */ | |
baba1b29 | 783 | if (!list_empty(&e->list)) |
21ca59b3 | 784 | remove_binfmt_handler(i_binfmt_misc(inode), e); |
1da177e4 | 785 | |
1c5976ef | 786 | inode_unlock(inode); |
e6084d4a MF |
787 | break; |
788 | default: | |
789 | return res; | |
1da177e4 | 790 | } |
e6084d4a | 791 | |
1da177e4 LT |
792 | return count; |
793 | } | |
794 | ||
4b6f5d20 | 795 | static const struct file_operations bm_entry_operations = { |
1da177e4 LT |
796 | .read = bm_entry_read, |
797 | .write = bm_entry_write, | |
6038f373 | 798 | .llseek = default_llseek, |
1da177e4 LT |
799 | }; |
800 | ||
801 | /* /register */ | |
802 | ||
803 | static ssize_t bm_register_write(struct file *file, const char __user *buffer, | |
804 | size_t count, loff_t *ppos) | |
805 | { | |
806 | Node *e; | |
807 | struct inode *inode; | |
ea7d4c04 AV |
808 | struct super_block *sb = file_inode(file)->i_sb; |
809 | struct dentry *root = sb->s_root, *dentry; | |
21ca59b3 | 810 | struct binfmt_misc *misc; |
1da177e4 | 811 | int err = 0; |
e7850f4d | 812 | struct file *f = NULL; |
1da177e4 LT |
813 | |
814 | e = create_entry(buffer, count); | |
815 | ||
816 | if (IS_ERR(e)) | |
817 | return PTR_ERR(e); | |
818 | ||
e7850f4d | 819 | if (e->flags & MISC_FMT_OPEN_FILE) { |
21ca59b3 CB |
820 | const struct cred *old_cred; |
821 | ||
822 | /* | |
823 | * Now that we support unprivileged binfmt_misc mounts make | |
824 | * sure we use the credentials that the register @file was | |
825 | * opened with to also open the interpreter. Before that this | |
826 | * didn't matter much as only a privileged process could open | |
827 | * the register file. | |
828 | */ | |
829 | old_cred = override_creds(file->f_cred); | |
e7850f4d | 830 | f = open_exec(e->interpreter); |
21ca59b3 | 831 | revert_creds(old_cred); |
e7850f4d LR |
832 | if (IS_ERR(f)) { |
833 | pr_notice("register: failed to install interpreter file %s\n", | |
834 | e->interpreter); | |
835 | kfree(e); | |
836 | return PTR_ERR(f); | |
837 | } | |
838 | e->interp_file = f; | |
839 | } | |
840 | ||
5955102c | 841 | inode_lock(d_inode(root)); |
1da177e4 LT |
842 | dentry = lookup_one_len(e->name, root, strlen(e->name)); |
843 | err = PTR_ERR(dentry); | |
844 | if (IS_ERR(dentry)) | |
845 | goto out; | |
846 | ||
847 | err = -EEXIST; | |
75c3cfa8 | 848 | if (d_really_is_positive(dentry)) |
1da177e4 LT |
849 | goto out2; |
850 | ||
851 | inode = bm_get_inode(sb, S_IFREG | 0644); | |
852 | ||
853 | err = -ENOMEM; | |
854 | if (!inode) | |
855 | goto out2; | |
856 | ||
1c5976ef | 857 | refcount_set(&e->users, 1); |
1da177e4 | 858 | e->dentry = dget(dentry); |
8e18e294 | 859 | inode->i_private = e; |
1da177e4 LT |
860 | inode->i_fop = &bm_entry_operations; |
861 | ||
862 | d_instantiate(dentry, inode); | |
21ca59b3 CB |
863 | misc = i_binfmt_misc(inode); |
864 | write_lock(&misc->entries_lock); | |
865 | list_add(&e->list, &misc->entries); | |
866 | write_unlock(&misc->entries_lock); | |
1da177e4 LT |
867 | |
868 | err = 0; | |
869 | out2: | |
870 | dput(dentry); | |
871 | out: | |
5955102c | 872 | inode_unlock(d_inode(root)); |
1da177e4 LT |
873 | |
874 | if (err) { | |
e7850f4d LR |
875 | if (f) |
876 | filp_close(f, NULL); | |
1da177e4 | 877 | kfree(e); |
948b701a | 878 | return err; |
1da177e4 LT |
879 | } |
880 | return count; | |
881 | } | |
882 | ||
4b6f5d20 | 883 | static const struct file_operations bm_register_operations = { |
1da177e4 | 884 | .write = bm_register_write, |
6038f373 | 885 | .llseek = noop_llseek, |
1da177e4 LT |
886 | }; |
887 | ||
888 | /* /status */ | |
889 | ||
890 | static ssize_t | |
891 | bm_status_read(struct file *file, char __user *buf, size_t nbytes, loff_t *ppos) | |
892 | { | |
21ca59b3 CB |
893 | struct binfmt_misc *misc; |
894 | char *s; | |
1da177e4 | 895 | |
21ca59b3 CB |
896 | misc = i_binfmt_misc(file_inode(file)); |
897 | s = misc->enabled ? "enabled\n" : "disabled\n"; | |
92f4c701 | 898 | return simple_read_from_buffer(buf, nbytes, ppos, s, strlen(s)); |
1da177e4 LT |
899 | } |
900 | ||
e6084d4a | 901 | static ssize_t bm_status_write(struct file *file, const char __user *buffer, |
1da177e4 LT |
902 | size_t count, loff_t *ppos) |
903 | { | |
21ca59b3 | 904 | struct binfmt_misc *misc; |
1da177e4 | 905 | int res = parse_command(buffer, count); |
1c5976ef CB |
906 | Node *e, *next; |
907 | struct inode *inode; | |
1da177e4 | 908 | |
21ca59b3 | 909 | misc = i_binfmt_misc(file_inode(file)); |
1da177e4 | 910 | switch (res) { |
e6084d4a MF |
911 | case 1: |
912 | /* Disable all handlers. */ | |
21ca59b3 | 913 | misc->enabled = false; |
e6084d4a MF |
914 | break; |
915 | case 2: | |
916 | /* Enable all handlers. */ | |
21ca59b3 | 917 | misc->enabled = true; |
e6084d4a MF |
918 | break; |
919 | case 3: | |
920 | /* Delete all handlers. */ | |
1c5976ef CB |
921 | inode = d_inode(file_inode(file)->i_sb->s_root); |
922 | inode_lock(inode); | |
1da177e4 | 923 | |
1c5976ef CB |
924 | /* |
925 | * In order to add new element or remove elements from the list | |
926 | * via bm_{entry,register,status}_write() inode_lock() on the | |
927 | * root inode must be held. | |
928 | * The lock is exclusive ensuring that the list can't be | |
929 | * modified. Only load_misc_binary() can access but does so | |
930 | * read-only. So we only need to take the write lock when we | |
931 | * actually remove the entry from the list. | |
932 | */ | |
21ca59b3 CB |
933 | list_for_each_entry_safe(e, next, &misc->entries, list) |
934 | remove_binfmt_handler(misc, e); | |
1da177e4 | 935 | |
1c5976ef | 936 | inode_unlock(inode); |
e6084d4a MF |
937 | break; |
938 | default: | |
939 | return res; | |
1da177e4 | 940 | } |
e6084d4a | 941 | |
1da177e4 LT |
942 | return count; |
943 | } | |
944 | ||
4b6f5d20 | 945 | static const struct file_operations bm_status_operations = { |
1da177e4 LT |
946 | .read = bm_status_read, |
947 | .write = bm_status_write, | |
6038f373 | 948 | .llseek = default_llseek, |
1da177e4 LT |
949 | }; |
950 | ||
951 | /* Superblock handling */ | |
952 | ||
21ca59b3 CB |
953 | static void bm_put_super(struct super_block *sb) |
954 | { | |
955 | struct user_namespace *user_ns = sb->s_fs_info; | |
956 | ||
957 | sb->s_fs_info = NULL; | |
958 | put_user_ns(user_ns); | |
959 | } | |
960 | ||
ee9b6d61 | 961 | static const struct super_operations s_ops = { |
1da177e4 | 962 | .statfs = simple_statfs, |
b57922d9 | 963 | .evict_inode = bm_evict_inode, |
21ca59b3 | 964 | .put_super = bm_put_super, |
1da177e4 LT |
965 | }; |
966 | ||
bc99a664 | 967 | static int bm_fill_super(struct super_block *sb, struct fs_context *fc) |
1da177e4 | 968 | { |
e6084d4a | 969 | int err; |
21ca59b3 CB |
970 | struct user_namespace *user_ns = sb->s_user_ns; |
971 | struct binfmt_misc *misc; | |
cda37124 | 972 | static const struct tree_descr bm_files[] = { |
1a1c9bb4 JL |
973 | [2] = {"status", &bm_status_operations, S_IWUSR|S_IRUGO}, |
974 | [3] = {"register", &bm_register_operations, S_IWUSR}, | |
1da177e4 LT |
975 | /* last one */ {""} |
976 | }; | |
e6084d4a | 977 | |
21ca59b3 CB |
978 | if (WARN_ON(user_ns != current_user_ns())) |
979 | return -EINVAL; | |
980 | ||
981 | /* | |
982 | * Lazily allocate a new binfmt_misc instance for this namespace, i.e. | |
983 | * do it here during the first mount of binfmt_misc. We don't need to | |
984 | * waste memory for every user namespace allocation. It's likely much | |
985 | * more common to not mount a separate binfmt_misc instance than it is | |
986 | * to mount one. | |
987 | * | |
988 | * While multiple superblocks can exist they are keyed by userns in | |
989 | * s_fs_info for binfmt_misc. Hence, the vfs guarantees that | |
990 | * bm_fill_super() is called exactly once whenever a binfmt_misc | |
991 | * superblock for a userns is created. This in turn lets us conclude | |
992 | * that when a binfmt_misc superblock is created for the first time for | |
993 | * a userns there's no one racing us. Therefore we don't need any | |
994 | * barriers when we dereference binfmt_misc. | |
995 | */ | |
996 | misc = user_ns->binfmt_misc; | |
997 | if (!misc) { | |
998 | /* | |
999 | * If it turns out that most user namespaces actually want to | |
1000 | * register their own binary type handler and therefore all | |
1001 | * create their own separate binfm_misc mounts we should | |
1002 | * consider turning this into a kmem cache. | |
1003 | */ | |
1004 | misc = kzalloc(sizeof(struct binfmt_misc), GFP_KERNEL); | |
1005 | if (!misc) | |
1006 | return -ENOMEM; | |
1007 | ||
1008 | INIT_LIST_HEAD(&misc->entries); | |
1009 | rwlock_init(&misc->entries_lock); | |
1010 | ||
1011 | /* Pairs with smp_load_acquire() in load_binfmt_misc(). */ | |
1012 | smp_store_release(&user_ns->binfmt_misc, misc); | |
1013 | } | |
1014 | ||
1015 | /* | |
1016 | * When the binfmt_misc superblock for this userns is shutdown | |
1017 | * ->enabled might have been set to false and we don't reinitialize | |
1018 | * ->enabled again in put_super() as someone might already be mounting | |
1019 | * binfmt_misc again. It also would be pointless since by the time | |
1020 | * ->put_super() is called we know that the binary type list for this | |
1021 | * bintfmt_misc mount is empty making load_misc_binary() return | |
1022 | * -ENOEXEC independent of whether ->enabled is true. Instead, if | |
1023 | * someone mounts binfmt_misc for the first time or again we simply | |
1024 | * reset ->enabled to true. | |
1025 | */ | |
1026 | misc->enabled = true; | |
1027 | ||
e6084d4a | 1028 | err = simple_fill_super(sb, BINFMTFS_MAGIC, bm_files); |
1da177e4 LT |
1029 | if (!err) |
1030 | sb->s_op = &s_ops; | |
1031 | return err; | |
1032 | } | |
1033 | ||
21ca59b3 CB |
1034 | static void bm_free(struct fs_context *fc) |
1035 | { | |
1036 | if (fc->s_fs_info) | |
1037 | put_user_ns(fc->s_fs_info); | |
1038 | } | |
1039 | ||
bc99a664 | 1040 | static int bm_get_tree(struct fs_context *fc) |
1da177e4 | 1041 | { |
21ca59b3 | 1042 | return get_tree_keyed(fc, bm_fill_super, get_user_ns(fc->user_ns)); |
bc99a664 DH |
1043 | } |
1044 | ||
1045 | static const struct fs_context_operations bm_context_ops = { | |
21ca59b3 | 1046 | .free = bm_free, |
bc99a664 DH |
1047 | .get_tree = bm_get_tree, |
1048 | }; | |
1049 | ||
1050 | static int bm_init_fs_context(struct fs_context *fc) | |
1051 | { | |
1052 | fc->ops = &bm_context_ops; | |
1053 | return 0; | |
1da177e4 LT |
1054 | } |
1055 | ||
1056 | static struct linux_binfmt misc_format = { | |
1057 | .module = THIS_MODULE, | |
1058 | .load_binary = load_misc_binary, | |
1059 | }; | |
1060 | ||
1061 | static struct file_system_type bm_fs_type = { | |
1062 | .owner = THIS_MODULE, | |
1063 | .name = "binfmt_misc", | |
bc99a664 | 1064 | .init_fs_context = bm_init_fs_context, |
21ca59b3 | 1065 | .fs_flags = FS_USERNS_MOUNT, |
1da177e4 LT |
1066 | .kill_sb = kill_litter_super, |
1067 | }; | |
7f78e035 | 1068 | MODULE_ALIAS_FS("binfmt_misc"); |
1da177e4 LT |
1069 | |
1070 | static int __init init_misc_binfmt(void) | |
1071 | { | |
1072 | int err = register_filesystem(&bm_fs_type); | |
8fc3dc5a AV |
1073 | if (!err) |
1074 | insert_binfmt(&misc_format); | |
b42bc9a3 | 1075 | return err; |
1da177e4 LT |
1076 | } |
1077 | ||
1078 | static void __exit exit_misc_binfmt(void) | |
1079 | { | |
1080 | unregister_binfmt(&misc_format); | |
1081 | unregister_filesystem(&bm_fs_type); | |
1082 | } | |
1083 | ||
1084 | core_initcall(init_misc_binfmt); | |
1085 | module_exit(exit_misc_binfmt); | |
2c2a3f62 | 1086 | MODULE_DESCRIPTION("Kernel support for miscellaneous binaries"); |
1da177e4 | 1087 | MODULE_LICENSE("GPL"); |