Commit | Line | Data |
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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 | ||
43 | static LIST_HEAD(entries); | |
44 | static int enabled = 1; | |
45 | ||
46 | enum {Enabled, Magic}; | |
e6084d4a MF |
47 | #define MISC_FMT_PRESERVE_ARGV0 (1 << 31) |
48 | #define MISC_FMT_OPEN_BINARY (1 << 30) | |
49 | #define MISC_FMT_CREDENTIALS (1 << 29) | |
948b701a | 50 | #define MISC_FMT_OPEN_FILE (1 << 28) |
1da177e4 LT |
51 | |
52 | typedef struct { | |
53 | struct list_head list; | |
54 | unsigned long flags; /* type, status, etc. */ | |
55 | int offset; /* offset of magic */ | |
56 | int size; /* size of magic/mask */ | |
57 | char *magic; /* magic or filename extension */ | |
58 | char *mask; /* mask, NULL for exact match */ | |
50097f74 | 59 | const char *interpreter; /* filename of interpreter */ |
1da177e4 LT |
60 | char *name; |
61 | struct dentry *dentry; | |
948b701a | 62 | struct file *interp_file; |
1da177e4 LT |
63 | } Node; |
64 | ||
65 | static DEFINE_RWLOCK(entries_lock); | |
1f5ce9e9 | 66 | static struct file_system_type bm_fs_type; |
1da177e4 LT |
67 | static struct vfsmount *bm_mnt; |
68 | static int entry_count; | |
69 | ||
bbaecc08 MF |
70 | /* |
71 | * Max length of the register string. Determined by: | |
72 | * - 7 delimiters | |
73 | * - name: ~50 bytes | |
74 | * - type: 1 byte | |
75 | * - offset: 3 bytes (has to be smaller than BINPRM_BUF_SIZE) | |
76 | * - magic: 128 bytes (512 in escaped form) | |
77 | * - mask: 128 bytes (512 in escaped form) | |
78 | * - interp: ~50 bytes | |
79 | * - flags: 5 bytes | |
80 | * Round that up a bit, and then back off to hold the internal data | |
81 | * (like struct Node). | |
82 | */ | |
83 | #define MAX_REGISTER_LENGTH 1920 | |
84 | ||
85 | /* | |
1da177e4 LT |
86 | * Check if we support the binfmt |
87 | * if we do, return the node, else NULL | |
88 | * locking is done in load_misc_binary | |
89 | */ | |
90 | static Node *check_file(struct linux_binprm *bprm) | |
91 | { | |
92 | char *p = strrchr(bprm->interp, '.'); | |
93 | struct list_head *l; | |
94 | ||
6b899c4e | 95 | /* Walk all the registered handlers. */ |
1da177e4 LT |
96 | list_for_each(l, &entries) { |
97 | Node *e = list_entry(l, Node, list); | |
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 | } | |
126 | return NULL; | |
127 | } | |
128 | ||
129 | /* | |
130 | * the loader itself | |
131 | */ | |
71613c3b | 132 | static int load_misc_binary(struct linux_binprm *bprm) |
1da177e4 LT |
133 | { |
134 | Node *fmt; | |
e6084d4a | 135 | struct file *interp_file = NULL; |
1da177e4 | 136 | int retval; |
1da177e4 LT |
137 | |
138 | retval = -ENOEXEC; | |
139 | if (!enabled) | |
43a4f261 | 140 | return retval; |
1da177e4 LT |
141 | |
142 | /* to keep locking time low, we copy the interpreter string */ | |
143 | read_lock(&entries_lock); | |
144 | fmt = check_file(bprm); | |
50097f74 | 145 | if (fmt) |
43a4f261 | 146 | dget(fmt->dentry); |
1da177e4 LT |
147 | read_unlock(&entries_lock); |
148 | if (!fmt) | |
43a4f261 | 149 | return retval; |
1da177e4 | 150 | |
51f39a1f | 151 | /* Need to be able to load the file after exec */ |
43a4f261 | 152 | retval = -ENOENT; |
51f39a1f | 153 | if (bprm->interp_flags & BINPRM_FLAGS_PATH_INACCESSIBLE) |
43a4f261 | 154 | goto ret; |
51f39a1f | 155 | |
1da177e4 | 156 | if (!(fmt->flags & MISC_FMT_PRESERVE_ARGV0)) { |
b6a2fea3 OW |
157 | retval = remove_arg_zero(bprm); |
158 | if (retval) | |
e6084d4a | 159 | goto ret; |
1da177e4 LT |
160 | } |
161 | ||
162 | if (fmt->flags & MISC_FMT_OPEN_BINARY) { | |
b8a61c9e EB |
163 | /* Pass the open binary to the interpreter */ |
164 | bprm->have_execfd = 1; | |
165 | bprm->executable = bprm->file; | |
1da177e4 LT |
166 | |
167 | allow_write_access(bprm->file); | |
168 | bprm->file = NULL; | |
e6084d4a MF |
169 | } else { |
170 | allow_write_access(bprm->file); | |
171 | fput(bprm->file); | |
172 | bprm->file = NULL; | |
173 | } | |
1da177e4 | 174 | /* make argv[1] be the path to the binary */ |
e6084d4a | 175 | retval = copy_strings_kernel(1, &bprm->interp, bprm); |
1da177e4 | 176 | if (retval < 0) |
b8a61c9e | 177 | goto ret; |
1da177e4 LT |
178 | bprm->argc++; |
179 | ||
180 | /* add the interp as argv[0] */ | |
50097f74 | 181 | retval = copy_strings_kernel(1, &fmt->interpreter, bprm); |
1da177e4 | 182 | if (retval < 0) |
b8a61c9e | 183 | goto ret; |
e6084d4a | 184 | bprm->argc++; |
1da177e4 | 185 | |
b66c5984 | 186 | /* Update interp in case binfmt_script needs it. */ |
50097f74 | 187 | retval = bprm_change_interp(fmt->interpreter, bprm); |
b66c5984 | 188 | if (retval < 0) |
b8a61c9e | 189 | goto ret; |
1da177e4 | 190 | |
eb23aa03 | 191 | if (fmt->flags & MISC_FMT_OPEN_FILE) { |
19f391eb | 192 | interp_file = file_clone_open(fmt->interp_file); |
948b701a JB |
193 | if (!IS_ERR(interp_file)) |
194 | deny_write_access(interp_file); | |
195 | } else { | |
50097f74 | 196 | interp_file = open_exec(fmt->interpreter); |
948b701a | 197 | } |
e6084d4a MF |
198 | retval = PTR_ERR(interp_file); |
199 | if (IS_ERR(interp_file)) | |
b8a61c9e | 200 | goto ret; |
1da177e4 LT |
201 | |
202 | bprm->file = interp_file; | |
a16b3357 EB |
203 | if (fmt->flags & MISC_FMT_CREDENTIALS) |
204 | bprm->preserve_creds = 1; | |
1da177e4 | 205 | |
3c456bfc | 206 | retval = search_binary_handler(bprm); |
1da177e4 | 207 | if (retval < 0) |
b8a61c9e | 208 | goto ret; |
1da177e4 | 209 | |
e6084d4a | 210 | ret: |
43a4f261 | 211 | dput(fmt->dentry); |
1da177e4 | 212 | return retval; |
1da177e4 LT |
213 | } |
214 | ||
215 | /* Command parsers */ | |
216 | ||
217 | /* | |
218 | * parses and copies one argument enclosed in del from *sp to *dp, | |
219 | * recognising the \x special. | |
220 | * returns pointer to the copied argument or NULL in case of an | |
221 | * error (and sets err) or null argument length. | |
222 | */ | |
223 | static char *scanarg(char *s, char del) | |
224 | { | |
225 | char c; | |
226 | ||
227 | while ((c = *s++) != del) { | |
228 | if (c == '\\' && *s == 'x') { | |
229 | s++; | |
230 | if (!isxdigit(*s++)) | |
231 | return NULL; | |
232 | if (!isxdigit(*s++)) | |
233 | return NULL; | |
234 | } | |
235 | } | |
7d65cf10 | 236 | s[-1] ='\0'; |
1da177e4 LT |
237 | return s; |
238 | } | |
239 | ||
e6084d4a | 240 | static char *check_special_flags(char *sfs, Node *e) |
1da177e4 | 241 | { |
e6084d4a | 242 | char *p = sfs; |
1da177e4 LT |
243 | int cont = 1; |
244 | ||
245 | /* special flags */ | |
246 | while (cont) { | |
247 | switch (*p) { | |
e6084d4a MF |
248 | case 'P': |
249 | pr_debug("register: flag: P (preserve argv0)\n"); | |
250 | p++; | |
251 | e->flags |= MISC_FMT_PRESERVE_ARGV0; | |
252 | break; | |
253 | case 'O': | |
254 | pr_debug("register: flag: O (open binary)\n"); | |
255 | p++; | |
256 | e->flags |= MISC_FMT_OPEN_BINARY; | |
257 | break; | |
258 | case 'C': | |
259 | pr_debug("register: flag: C (preserve creds)\n"); | |
260 | p++; | |
261 | /* this flags also implies the | |
262 | open-binary flag */ | |
263 | e->flags |= (MISC_FMT_CREDENTIALS | | |
264 | MISC_FMT_OPEN_BINARY); | |
265 | break; | |
948b701a JB |
266 | case 'F': |
267 | pr_debug("register: flag: F: open interpreter file now\n"); | |
268 | p++; | |
269 | e->flags |= MISC_FMT_OPEN_FILE; | |
270 | break; | |
e6084d4a MF |
271 | default: |
272 | cont = 0; | |
1da177e4 LT |
273 | } |
274 | } | |
275 | ||
276 | return p; | |
277 | } | |
e6084d4a | 278 | |
1da177e4 LT |
279 | /* |
280 | * This registers a new binary format, it recognises the syntax | |
281 | * ':name:type:offset:magic:mask:interpreter:flags' | |
282 | * where the ':' is the IFS, that can be chosen with the first char | |
283 | */ | |
284 | static Node *create_entry(const char __user *buffer, size_t count) | |
285 | { | |
286 | Node *e; | |
287 | int memsize, err; | |
288 | char *buf, *p; | |
289 | char del; | |
290 | ||
6b899c4e MF |
291 | pr_debug("register: received %zu bytes\n", count); |
292 | ||
1da177e4 LT |
293 | /* some sanity checks */ |
294 | err = -EINVAL; | |
bbaecc08 | 295 | if ((count < 11) || (count > MAX_REGISTER_LENGTH)) |
1da177e4 LT |
296 | goto out; |
297 | ||
298 | err = -ENOMEM; | |
299 | memsize = sizeof(Node) + count + 8; | |
f7e1ad1a | 300 | e = kmalloc(memsize, GFP_KERNEL); |
1da177e4 LT |
301 | if (!e) |
302 | goto out; | |
303 | ||
304 | p = buf = (char *)e + sizeof(Node); | |
305 | ||
306 | memset(e, 0, sizeof(Node)); | |
307 | if (copy_from_user(buf, buffer, count)) | |
e6084d4a | 308 | goto efault; |
1da177e4 LT |
309 | |
310 | del = *p++; /* delimeter */ | |
311 | ||
6b899c4e MF |
312 | pr_debug("register: delim: %#x {%c}\n", del, del); |
313 | ||
314 | /* Pad the buffer with the delim to simplify parsing below. */ | |
e6084d4a | 315 | memset(buf + count, del, 8); |
1da177e4 | 316 | |
6b899c4e | 317 | /* Parse the 'name' field. */ |
1da177e4 LT |
318 | e->name = p; |
319 | p = strchr(p, del); | |
320 | if (!p) | |
e6084d4a | 321 | goto einval; |
1da177e4 LT |
322 | *p++ = '\0'; |
323 | if (!e->name[0] || | |
324 | !strcmp(e->name, ".") || | |
325 | !strcmp(e->name, "..") || | |
326 | strchr(e->name, '/')) | |
e6084d4a | 327 | goto einval; |
6b899c4e MF |
328 | |
329 | pr_debug("register: name: {%s}\n", e->name); | |
330 | ||
331 | /* Parse the 'type' field. */ | |
1da177e4 | 332 | switch (*p++) { |
6b899c4e MF |
333 | case 'E': |
334 | pr_debug("register: type: E (extension)\n"); | |
335 | e->flags = 1 << Enabled; | |
336 | break; | |
337 | case 'M': | |
338 | pr_debug("register: type: M (magic)\n"); | |
339 | e->flags = (1 << Enabled) | (1 << Magic); | |
340 | break; | |
341 | default: | |
e6084d4a | 342 | goto einval; |
1da177e4 LT |
343 | } |
344 | if (*p++ != del) | |
e6084d4a | 345 | goto einval; |
6b899c4e | 346 | |
1da177e4 | 347 | if (test_bit(Magic, &e->flags)) { |
6b899c4e MF |
348 | /* Handle the 'M' (magic) format. */ |
349 | char *s; | |
350 | ||
351 | /* Parse the 'offset' field. */ | |
352 | s = strchr(p, del); | |
1da177e4 | 353 | if (!s) |
e6084d4a | 354 | goto einval; |
5cc41e09 TLSC |
355 | *s = '\0'; |
356 | if (p != s) { | |
357 | int r = kstrtoint(p, 10, &e->offset); | |
358 | if (r != 0 || e->offset < 0) | |
359 | goto einval; | |
360 | } | |
361 | p = s; | |
1da177e4 | 362 | if (*p++) |
e6084d4a | 363 | goto einval; |
6b899c4e MF |
364 | pr_debug("register: offset: %#x\n", e->offset); |
365 | ||
366 | /* Parse the 'magic' field. */ | |
1da177e4 LT |
367 | e->magic = p; |
368 | p = scanarg(p, del); | |
369 | if (!p) | |
e6084d4a | 370 | goto einval; |
7d65cf10 | 371 | if (!e->magic[0]) |
e6084d4a | 372 | goto einval; |
6b899c4e MF |
373 | if (USE_DEBUG) |
374 | print_hex_dump_bytes( | |
375 | KBUILD_MODNAME ": register: magic[raw]: ", | |
376 | DUMP_PREFIX_NONE, e->magic, p - e->magic); | |
377 | ||
378 | /* Parse the 'mask' field. */ | |
1da177e4 LT |
379 | e->mask = p; |
380 | p = scanarg(p, del); | |
381 | if (!p) | |
e6084d4a | 382 | goto einval; |
7d65cf10 | 383 | if (!e->mask[0]) { |
1da177e4 | 384 | e->mask = NULL; |
6b899c4e MF |
385 | pr_debug("register: mask[raw]: none\n"); |
386 | } else if (USE_DEBUG) | |
387 | print_hex_dump_bytes( | |
388 | KBUILD_MODNAME ": register: mask[raw]: ", | |
389 | DUMP_PREFIX_NONE, e->mask, p - e->mask); | |
390 | ||
391 | /* | |
392 | * Decode the magic & mask fields. | |
393 | * Note: while we might have accepted embedded NUL bytes from | |
394 | * above, the unescape helpers here will stop at the first one | |
395 | * it encounters. | |
396 | */ | |
8d82e180 AS |
397 | e->size = string_unescape_inplace(e->magic, UNESCAPE_HEX); |
398 | if (e->mask && | |
399 | string_unescape_inplace(e->mask, UNESCAPE_HEX) != e->size) | |
e6084d4a | 400 | goto einval; |
5cc41e09 TLSC |
401 | if (e->size > BINPRM_BUF_SIZE || |
402 | BINPRM_BUF_SIZE - e->size < e->offset) | |
e6084d4a | 403 | goto einval; |
6b899c4e MF |
404 | pr_debug("register: magic/mask length: %i\n", e->size); |
405 | if (USE_DEBUG) { | |
406 | print_hex_dump_bytes( | |
407 | KBUILD_MODNAME ": register: magic[decoded]: ", | |
408 | DUMP_PREFIX_NONE, e->magic, e->size); | |
409 | ||
410 | if (e->mask) { | |
411 | int i; | |
f7e1ad1a | 412 | char *masked = kmalloc(e->size, GFP_KERNEL); |
6b899c4e MF |
413 | |
414 | print_hex_dump_bytes( | |
415 | KBUILD_MODNAME ": register: mask[decoded]: ", | |
416 | DUMP_PREFIX_NONE, e->mask, e->size); | |
417 | ||
418 | if (masked) { | |
419 | for (i = 0; i < e->size; ++i) | |
420 | masked[i] = e->magic[i] & e->mask[i]; | |
421 | print_hex_dump_bytes( | |
422 | KBUILD_MODNAME ": register: magic[masked]: ", | |
423 | DUMP_PREFIX_NONE, masked, e->size); | |
424 | ||
425 | kfree(masked); | |
426 | } | |
427 | } | |
428 | } | |
1da177e4 | 429 | } else { |
6b899c4e MF |
430 | /* Handle the 'E' (extension) format. */ |
431 | ||
432 | /* Skip the 'offset' field. */ | |
1da177e4 LT |
433 | p = strchr(p, del); |
434 | if (!p) | |
e6084d4a | 435 | goto einval; |
1da177e4 | 436 | *p++ = '\0'; |
6b899c4e MF |
437 | |
438 | /* Parse the 'magic' field. */ | |
1da177e4 LT |
439 | e->magic = p; |
440 | p = strchr(p, del); | |
441 | if (!p) | |
e6084d4a | 442 | goto einval; |
1da177e4 LT |
443 | *p++ = '\0'; |
444 | if (!e->magic[0] || strchr(e->magic, '/')) | |
e6084d4a | 445 | goto einval; |
6b899c4e MF |
446 | pr_debug("register: extension: {%s}\n", e->magic); |
447 | ||
448 | /* Skip the 'mask' field. */ | |
1da177e4 LT |
449 | p = strchr(p, del); |
450 | if (!p) | |
e6084d4a | 451 | goto einval; |
1da177e4 LT |
452 | *p++ = '\0'; |
453 | } | |
6b899c4e MF |
454 | |
455 | /* Parse the 'interpreter' field. */ | |
1da177e4 LT |
456 | e->interpreter = p; |
457 | p = strchr(p, del); | |
458 | if (!p) | |
e6084d4a | 459 | goto einval; |
1da177e4 LT |
460 | *p++ = '\0'; |
461 | if (!e->interpreter[0]) | |
e6084d4a | 462 | goto einval; |
6b899c4e | 463 | pr_debug("register: interpreter: {%s}\n", e->interpreter); |
1da177e4 | 464 | |
6b899c4e | 465 | /* Parse the 'flags' field. */ |
e6084d4a | 466 | p = check_special_flags(p, e); |
1da177e4 LT |
467 | if (*p == '\n') |
468 | p++; | |
469 | if (p != buf + count) | |
e6084d4a MF |
470 | goto einval; |
471 | ||
1da177e4 LT |
472 | return e; |
473 | ||
474 | out: | |
475 | return ERR_PTR(err); | |
476 | ||
e6084d4a | 477 | efault: |
1da177e4 LT |
478 | kfree(e); |
479 | return ERR_PTR(-EFAULT); | |
e6084d4a | 480 | einval: |
1da177e4 LT |
481 | kfree(e); |
482 | return ERR_PTR(-EINVAL); | |
483 | } | |
484 | ||
485 | /* | |
486 | * Set status of entry/binfmt_misc: | |
487 | * '1' enables, '0' disables and '-1' clears entry/binfmt_misc | |
488 | */ | |
489 | static int parse_command(const char __user *buffer, size_t count) | |
490 | { | |
491 | char s[4]; | |
492 | ||
1da177e4 LT |
493 | if (count > 3) |
494 | return -EINVAL; | |
495 | if (copy_from_user(s, buffer, count)) | |
496 | return -EFAULT; | |
de8288b1 AB |
497 | if (!count) |
498 | return 0; | |
e6084d4a | 499 | if (s[count - 1] == '\n') |
1da177e4 LT |
500 | count--; |
501 | if (count == 1 && s[0] == '0') | |
502 | return 1; | |
503 | if (count == 1 && s[0] == '1') | |
504 | return 2; | |
505 | if (count == 2 && s[0] == '-' && s[1] == '1') | |
506 | return 3; | |
507 | return -EINVAL; | |
508 | } | |
509 | ||
510 | /* generic stuff */ | |
511 | ||
512 | static void entry_status(Node *e, char *page) | |
513 | { | |
6ceafb88 RV |
514 | char *dp = page; |
515 | const char *status = "disabled"; | |
1da177e4 LT |
516 | |
517 | if (test_bit(Enabled, &e->flags)) | |
518 | status = "enabled"; | |
519 | ||
520 | if (!VERBOSE_STATUS) { | |
521 | sprintf(page, "%s\n", status); | |
522 | return; | |
523 | } | |
524 | ||
6ceafb88 | 525 | dp += sprintf(dp, "%s\ninterpreter %s\n", status, e->interpreter); |
1da177e4 LT |
526 | |
527 | /* print the special flags */ | |
6ceafb88 | 528 | dp += sprintf(dp, "flags: "); |
e6084d4a MF |
529 | if (e->flags & MISC_FMT_PRESERVE_ARGV0) |
530 | *dp++ = 'P'; | |
531 | if (e->flags & MISC_FMT_OPEN_BINARY) | |
532 | *dp++ = 'O'; | |
533 | if (e->flags & MISC_FMT_CREDENTIALS) | |
534 | *dp++ = 'C'; | |
948b701a JB |
535 | if (e->flags & MISC_FMT_OPEN_FILE) |
536 | *dp++ = 'F'; | |
e6084d4a | 537 | *dp++ = '\n'; |
1da177e4 LT |
538 | |
539 | if (!test_bit(Magic, &e->flags)) { | |
540 | sprintf(dp, "extension .%s\n", e->magic); | |
541 | } else { | |
6ceafb88 RV |
542 | dp += sprintf(dp, "offset %i\nmagic ", e->offset); |
543 | dp = bin2hex(dp, e->magic, e->size); | |
1da177e4 | 544 | if (e->mask) { |
6ceafb88 RV |
545 | dp += sprintf(dp, "\nmask "); |
546 | dp = bin2hex(dp, e->mask, e->size); | |
1da177e4 LT |
547 | } |
548 | *dp++ = '\n'; | |
549 | *dp = '\0'; | |
550 | } | |
551 | } | |
552 | ||
553 | static struct inode *bm_get_inode(struct super_block *sb, int mode) | |
554 | { | |
e6084d4a | 555 | struct inode *inode = new_inode(sb); |
1da177e4 LT |
556 | |
557 | if (inode) { | |
85fe4025 | 558 | inode->i_ino = get_next_ino(); |
1da177e4 | 559 | inode->i_mode = mode; |
1da177e4 | 560 | inode->i_atime = inode->i_mtime = inode->i_ctime = |
c2050a45 | 561 | current_time(inode); |
1da177e4 LT |
562 | } |
563 | return inode; | |
564 | } | |
565 | ||
b57922d9 | 566 | static void bm_evict_inode(struct inode *inode) |
1da177e4 | 567 | { |
83f91827 ON |
568 | Node *e = inode->i_private; |
569 | ||
7e866006 | 570 | if (e && e->flags & MISC_FMT_OPEN_FILE) |
83f91827 ON |
571 | filp_close(e->interp_file, NULL); |
572 | ||
dbd5768f | 573 | clear_inode(inode); |
83f91827 | 574 | kfree(e); |
1da177e4 LT |
575 | } |
576 | ||
577 | static void kill_node(Node *e) | |
578 | { | |
579 | struct dentry *dentry; | |
580 | ||
581 | write_lock(&entries_lock); | |
baba1b29 | 582 | list_del_init(&e->list); |
1da177e4 LT |
583 | write_unlock(&entries_lock); |
584 | ||
baba1b29 ON |
585 | dentry = e->dentry; |
586 | drop_nlink(d_inode(dentry)); | |
587 | d_drop(dentry); | |
588 | dput(dentry); | |
589 | simple_release_fs(&bm_mnt, &entry_count); | |
1da177e4 LT |
590 | } |
591 | ||
592 | /* /<entry> */ | |
593 | ||
594 | static ssize_t | |
e6084d4a | 595 | bm_entry_read(struct file *file, char __user *buf, size_t nbytes, loff_t *ppos) |
1da177e4 | 596 | { |
496ad9aa | 597 | Node *e = file_inode(file)->i_private; |
1da177e4 LT |
598 | ssize_t res; |
599 | char *page; | |
1da177e4 | 600 | |
e6084d4a MF |
601 | page = (char *) __get_free_page(GFP_KERNEL); |
602 | if (!page) | |
1da177e4 LT |
603 | return -ENOMEM; |
604 | ||
605 | entry_status(e, page); | |
1da177e4 | 606 | |
6e2c10a1 AM |
607 | res = simple_read_from_buffer(buf, nbytes, ppos, page, strlen(page)); |
608 | ||
1da177e4 LT |
609 | free_page((unsigned long) page); |
610 | return res; | |
611 | } | |
612 | ||
613 | static ssize_t bm_entry_write(struct file *file, const char __user *buffer, | |
614 | size_t count, loff_t *ppos) | |
615 | { | |
616 | struct dentry *root; | |
496ad9aa | 617 | Node *e = file_inode(file)->i_private; |
1da177e4 LT |
618 | int res = parse_command(buffer, count); |
619 | ||
620 | switch (res) { | |
e6084d4a MF |
621 | case 1: |
622 | /* Disable this handler. */ | |
623 | clear_bit(Enabled, &e->flags); | |
624 | break; | |
625 | case 2: | |
626 | /* Enable this handler. */ | |
627 | set_bit(Enabled, &e->flags); | |
628 | break; | |
629 | case 3: | |
630 | /* Delete this handler. */ | |
ea7d4c04 | 631 | root = file_inode(file)->i_sb->s_root; |
5955102c | 632 | inode_lock(d_inode(root)); |
1da177e4 | 633 | |
baba1b29 ON |
634 | if (!list_empty(&e->list)) |
635 | kill_node(e); | |
1da177e4 | 636 | |
5955102c | 637 | inode_unlock(d_inode(root)); |
e6084d4a MF |
638 | break; |
639 | default: | |
640 | return res; | |
1da177e4 | 641 | } |
e6084d4a | 642 | |
1da177e4 LT |
643 | return count; |
644 | } | |
645 | ||
4b6f5d20 | 646 | static const struct file_operations bm_entry_operations = { |
1da177e4 LT |
647 | .read = bm_entry_read, |
648 | .write = bm_entry_write, | |
6038f373 | 649 | .llseek = default_llseek, |
1da177e4 LT |
650 | }; |
651 | ||
652 | /* /register */ | |
653 | ||
654 | static ssize_t bm_register_write(struct file *file, const char __user *buffer, | |
655 | size_t count, loff_t *ppos) | |
656 | { | |
657 | Node *e; | |
658 | struct inode *inode; | |
ea7d4c04 AV |
659 | struct super_block *sb = file_inode(file)->i_sb; |
660 | struct dentry *root = sb->s_root, *dentry; | |
1da177e4 LT |
661 | int err = 0; |
662 | ||
663 | e = create_entry(buffer, count); | |
664 | ||
665 | if (IS_ERR(e)) | |
666 | return PTR_ERR(e); | |
667 | ||
5955102c | 668 | inode_lock(d_inode(root)); |
1da177e4 LT |
669 | dentry = lookup_one_len(e->name, root, strlen(e->name)); |
670 | err = PTR_ERR(dentry); | |
671 | if (IS_ERR(dentry)) | |
672 | goto out; | |
673 | ||
674 | err = -EEXIST; | |
75c3cfa8 | 675 | if (d_really_is_positive(dentry)) |
1da177e4 LT |
676 | goto out2; |
677 | ||
678 | inode = bm_get_inode(sb, S_IFREG | 0644); | |
679 | ||
680 | err = -ENOMEM; | |
681 | if (!inode) | |
682 | goto out2; | |
683 | ||
1f5ce9e9 | 684 | err = simple_pin_fs(&bm_fs_type, &bm_mnt, &entry_count); |
1da177e4 LT |
685 | if (err) { |
686 | iput(inode); | |
687 | inode = NULL; | |
688 | goto out2; | |
689 | } | |
690 | ||
948b701a JB |
691 | if (e->flags & MISC_FMT_OPEN_FILE) { |
692 | struct file *f; | |
693 | ||
694 | f = open_exec(e->interpreter); | |
695 | if (IS_ERR(f)) { | |
696 | err = PTR_ERR(f); | |
697 | pr_notice("register: failed to install interpreter file %s\n", e->interpreter); | |
698 | simple_release_fs(&bm_mnt, &entry_count); | |
699 | iput(inode); | |
700 | inode = NULL; | |
701 | goto out2; | |
702 | } | |
703 | e->interp_file = f; | |
704 | } | |
705 | ||
1da177e4 | 706 | e->dentry = dget(dentry); |
8e18e294 | 707 | inode->i_private = e; |
1da177e4 LT |
708 | inode->i_fop = &bm_entry_operations; |
709 | ||
710 | d_instantiate(dentry, inode); | |
711 | write_lock(&entries_lock); | |
712 | list_add(&e->list, &entries); | |
713 | write_unlock(&entries_lock); | |
714 | ||
715 | err = 0; | |
716 | out2: | |
717 | dput(dentry); | |
718 | out: | |
5955102c | 719 | inode_unlock(d_inode(root)); |
1da177e4 LT |
720 | |
721 | if (err) { | |
722 | kfree(e); | |
948b701a | 723 | return err; |
1da177e4 LT |
724 | } |
725 | return count; | |
726 | } | |
727 | ||
4b6f5d20 | 728 | static const struct file_operations bm_register_operations = { |
1da177e4 | 729 | .write = bm_register_write, |
6038f373 | 730 | .llseek = noop_llseek, |
1da177e4 LT |
731 | }; |
732 | ||
733 | /* /status */ | |
734 | ||
735 | static ssize_t | |
736 | bm_status_read(struct file *file, char __user *buf, size_t nbytes, loff_t *ppos) | |
737 | { | |
87113e80 | 738 | char *s = enabled ? "enabled\n" : "disabled\n"; |
1da177e4 | 739 | |
92f4c701 | 740 | return simple_read_from_buffer(buf, nbytes, ppos, s, strlen(s)); |
1da177e4 LT |
741 | } |
742 | ||
e6084d4a | 743 | static ssize_t bm_status_write(struct file *file, const char __user *buffer, |
1da177e4 LT |
744 | size_t count, loff_t *ppos) |
745 | { | |
746 | int res = parse_command(buffer, count); | |
747 | struct dentry *root; | |
748 | ||
749 | switch (res) { | |
e6084d4a MF |
750 | case 1: |
751 | /* Disable all handlers. */ | |
752 | enabled = 0; | |
753 | break; | |
754 | case 2: | |
755 | /* Enable all handlers. */ | |
756 | enabled = 1; | |
757 | break; | |
758 | case 3: | |
759 | /* Delete all handlers. */ | |
ea7d4c04 | 760 | root = file_inode(file)->i_sb->s_root; |
5955102c | 761 | inode_lock(d_inode(root)); |
1da177e4 | 762 | |
e6084d4a | 763 | while (!list_empty(&entries)) |
baba1b29 | 764 | kill_node(list_first_entry(&entries, Node, list)); |
1da177e4 | 765 | |
5955102c | 766 | inode_unlock(d_inode(root)); |
e6084d4a MF |
767 | break; |
768 | default: | |
769 | return res; | |
1da177e4 | 770 | } |
e6084d4a | 771 | |
1da177e4 LT |
772 | return count; |
773 | } | |
774 | ||
4b6f5d20 | 775 | static const struct file_operations bm_status_operations = { |
1da177e4 LT |
776 | .read = bm_status_read, |
777 | .write = bm_status_write, | |
6038f373 | 778 | .llseek = default_llseek, |
1da177e4 LT |
779 | }; |
780 | ||
781 | /* Superblock handling */ | |
782 | ||
ee9b6d61 | 783 | static const struct super_operations s_ops = { |
1da177e4 | 784 | .statfs = simple_statfs, |
b57922d9 | 785 | .evict_inode = bm_evict_inode, |
1da177e4 LT |
786 | }; |
787 | ||
bc99a664 | 788 | static int bm_fill_super(struct super_block *sb, struct fs_context *fc) |
1da177e4 | 789 | { |
e6084d4a | 790 | int err; |
cda37124 | 791 | static const struct tree_descr bm_files[] = { |
1a1c9bb4 JL |
792 | [2] = {"status", &bm_status_operations, S_IWUSR|S_IRUGO}, |
793 | [3] = {"register", &bm_register_operations, S_IWUSR}, | |
1da177e4 LT |
794 | /* last one */ {""} |
795 | }; | |
e6084d4a MF |
796 | |
797 | err = simple_fill_super(sb, BINFMTFS_MAGIC, bm_files); | |
1da177e4 LT |
798 | if (!err) |
799 | sb->s_op = &s_ops; | |
800 | return err; | |
801 | } | |
802 | ||
bc99a664 | 803 | static int bm_get_tree(struct fs_context *fc) |
1da177e4 | 804 | { |
bc99a664 DH |
805 | return get_tree_single(fc, bm_fill_super); |
806 | } | |
807 | ||
808 | static const struct fs_context_operations bm_context_ops = { | |
809 | .get_tree = bm_get_tree, | |
810 | }; | |
811 | ||
812 | static int bm_init_fs_context(struct fs_context *fc) | |
813 | { | |
814 | fc->ops = &bm_context_ops; | |
815 | return 0; | |
1da177e4 LT |
816 | } |
817 | ||
818 | static struct linux_binfmt misc_format = { | |
819 | .module = THIS_MODULE, | |
820 | .load_binary = load_misc_binary, | |
821 | }; | |
822 | ||
823 | static struct file_system_type bm_fs_type = { | |
824 | .owner = THIS_MODULE, | |
825 | .name = "binfmt_misc", | |
bc99a664 | 826 | .init_fs_context = bm_init_fs_context, |
1da177e4 LT |
827 | .kill_sb = kill_litter_super, |
828 | }; | |
7f78e035 | 829 | MODULE_ALIAS_FS("binfmt_misc"); |
1da177e4 LT |
830 | |
831 | static int __init init_misc_binfmt(void) | |
832 | { | |
833 | int err = register_filesystem(&bm_fs_type); | |
8fc3dc5a AV |
834 | if (!err) |
835 | insert_binfmt(&misc_format); | |
1da177e4 LT |
836 | return err; |
837 | } | |
838 | ||
839 | static void __exit exit_misc_binfmt(void) | |
840 | { | |
841 | unregister_binfmt(&misc_format); | |
842 | unregister_filesystem(&bm_fs_type); | |
843 | } | |
844 | ||
845 | core_initcall(init_misc_binfmt); | |
846 | module_exit(exit_misc_binfmt); | |
847 | MODULE_LICENSE("GPL"); |