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 | |
2347961b LV |
156 | if (fmt->flags & MISC_FMT_PRESERVE_ARGV0) { |
157 | bprm->interp_flags |= BINPRM_FLAGS_PRESERVE_ARGV0; | |
158 | } else { | |
b6a2fea3 OW |
159 | retval = remove_arg_zero(bprm); |
160 | if (retval) | |
e6084d4a | 161 | goto ret; |
1da177e4 LT |
162 | } |
163 | ||
bc2bf338 | 164 | if (fmt->flags & MISC_FMT_OPEN_BINARY) |
b8a61c9e | 165 | bprm->have_execfd = 1; |
1da177e4 | 166 | |
1da177e4 | 167 | /* make argv[1] be the path to the binary */ |
986db2d1 | 168 | retval = copy_string_kernel(bprm->interp, bprm); |
1da177e4 | 169 | if (retval < 0) |
b8a61c9e | 170 | goto ret; |
1da177e4 LT |
171 | bprm->argc++; |
172 | ||
173 | /* add the interp as argv[0] */ | |
986db2d1 | 174 | retval = copy_string_kernel(fmt->interpreter, bprm); |
1da177e4 | 175 | if (retval < 0) |
b8a61c9e | 176 | goto ret; |
e6084d4a | 177 | bprm->argc++; |
1da177e4 | 178 | |
b66c5984 | 179 | /* Update interp in case binfmt_script needs it. */ |
50097f74 | 180 | retval = bprm_change_interp(fmt->interpreter, bprm); |
b66c5984 | 181 | if (retval < 0) |
b8a61c9e | 182 | goto ret; |
1da177e4 | 183 | |
eb23aa03 | 184 | if (fmt->flags & MISC_FMT_OPEN_FILE) { |
19f391eb | 185 | interp_file = file_clone_open(fmt->interp_file); |
948b701a JB |
186 | if (!IS_ERR(interp_file)) |
187 | deny_write_access(interp_file); | |
188 | } else { | |
50097f74 | 189 | interp_file = open_exec(fmt->interpreter); |
948b701a | 190 | } |
e6084d4a MF |
191 | retval = PTR_ERR(interp_file); |
192 | if (IS_ERR(interp_file)) | |
b8a61c9e | 193 | goto ret; |
1da177e4 | 194 | |
bc2bf338 | 195 | bprm->interpreter = interp_file; |
a16b3357 | 196 | if (fmt->flags & MISC_FMT_CREDENTIALS) |
56305aa9 | 197 | bprm->execfd_creds = 1; |
1da177e4 | 198 | |
bc2bf338 | 199 | retval = 0; |
e6084d4a | 200 | ret: |
43a4f261 | 201 | dput(fmt->dentry); |
1da177e4 | 202 | return retval; |
1da177e4 LT |
203 | } |
204 | ||
205 | /* Command parsers */ | |
206 | ||
207 | /* | |
208 | * parses and copies one argument enclosed in del from *sp to *dp, | |
209 | * recognising the \x special. | |
210 | * returns pointer to the copied argument or NULL in case of an | |
211 | * error (and sets err) or null argument length. | |
212 | */ | |
213 | static char *scanarg(char *s, char del) | |
214 | { | |
215 | char c; | |
216 | ||
217 | while ((c = *s++) != del) { | |
218 | if (c == '\\' && *s == 'x') { | |
219 | s++; | |
220 | if (!isxdigit(*s++)) | |
221 | return NULL; | |
222 | if (!isxdigit(*s++)) | |
223 | return NULL; | |
224 | } | |
225 | } | |
7d65cf10 | 226 | s[-1] ='\0'; |
1da177e4 LT |
227 | return s; |
228 | } | |
229 | ||
e6084d4a | 230 | static char *check_special_flags(char *sfs, Node *e) |
1da177e4 | 231 | { |
e6084d4a | 232 | char *p = sfs; |
1da177e4 LT |
233 | int cont = 1; |
234 | ||
235 | /* special flags */ | |
236 | while (cont) { | |
237 | switch (*p) { | |
e6084d4a MF |
238 | case 'P': |
239 | pr_debug("register: flag: P (preserve argv0)\n"); | |
240 | p++; | |
241 | e->flags |= MISC_FMT_PRESERVE_ARGV0; | |
242 | break; | |
243 | case 'O': | |
244 | pr_debug("register: flag: O (open binary)\n"); | |
245 | p++; | |
246 | e->flags |= MISC_FMT_OPEN_BINARY; | |
247 | break; | |
248 | case 'C': | |
249 | pr_debug("register: flag: C (preserve creds)\n"); | |
250 | p++; | |
251 | /* this flags also implies the | |
252 | open-binary flag */ | |
253 | e->flags |= (MISC_FMT_CREDENTIALS | | |
254 | MISC_FMT_OPEN_BINARY); | |
255 | break; | |
948b701a JB |
256 | case 'F': |
257 | pr_debug("register: flag: F: open interpreter file now\n"); | |
258 | p++; | |
259 | e->flags |= MISC_FMT_OPEN_FILE; | |
260 | break; | |
e6084d4a MF |
261 | default: |
262 | cont = 0; | |
1da177e4 LT |
263 | } |
264 | } | |
265 | ||
266 | return p; | |
267 | } | |
e6084d4a | 268 | |
1da177e4 LT |
269 | /* |
270 | * This registers a new binary format, it recognises the syntax | |
271 | * ':name:type:offset:magic:mask:interpreter:flags' | |
272 | * where the ':' is the IFS, that can be chosen with the first char | |
273 | */ | |
274 | static Node *create_entry(const char __user *buffer, size_t count) | |
275 | { | |
276 | Node *e; | |
277 | int memsize, err; | |
278 | char *buf, *p; | |
279 | char del; | |
280 | ||
6b899c4e MF |
281 | pr_debug("register: received %zu bytes\n", count); |
282 | ||
1da177e4 LT |
283 | /* some sanity checks */ |
284 | err = -EINVAL; | |
bbaecc08 | 285 | if ((count < 11) || (count > MAX_REGISTER_LENGTH)) |
1da177e4 LT |
286 | goto out; |
287 | ||
288 | err = -ENOMEM; | |
289 | memsize = sizeof(Node) + count + 8; | |
f7e1ad1a | 290 | e = kmalloc(memsize, GFP_KERNEL); |
1da177e4 LT |
291 | if (!e) |
292 | goto out; | |
293 | ||
294 | p = buf = (char *)e + sizeof(Node); | |
295 | ||
296 | memset(e, 0, sizeof(Node)); | |
297 | if (copy_from_user(buf, buffer, count)) | |
e6084d4a | 298 | goto efault; |
1da177e4 LT |
299 | |
300 | del = *p++; /* delimeter */ | |
301 | ||
6b899c4e MF |
302 | pr_debug("register: delim: %#x {%c}\n", del, del); |
303 | ||
304 | /* Pad the buffer with the delim to simplify parsing below. */ | |
e6084d4a | 305 | memset(buf + count, del, 8); |
1da177e4 | 306 | |
6b899c4e | 307 | /* Parse the 'name' field. */ |
1da177e4 LT |
308 | e->name = p; |
309 | p = strchr(p, del); | |
310 | if (!p) | |
e6084d4a | 311 | goto einval; |
1da177e4 LT |
312 | *p++ = '\0'; |
313 | if (!e->name[0] || | |
314 | !strcmp(e->name, ".") || | |
315 | !strcmp(e->name, "..") || | |
316 | strchr(e->name, '/')) | |
e6084d4a | 317 | goto einval; |
6b899c4e MF |
318 | |
319 | pr_debug("register: name: {%s}\n", e->name); | |
320 | ||
321 | /* Parse the 'type' field. */ | |
1da177e4 | 322 | switch (*p++) { |
6b899c4e MF |
323 | case 'E': |
324 | pr_debug("register: type: E (extension)\n"); | |
325 | e->flags = 1 << Enabled; | |
326 | break; | |
327 | case 'M': | |
328 | pr_debug("register: type: M (magic)\n"); | |
329 | e->flags = (1 << Enabled) | (1 << Magic); | |
330 | break; | |
331 | default: | |
e6084d4a | 332 | goto einval; |
1da177e4 LT |
333 | } |
334 | if (*p++ != del) | |
e6084d4a | 335 | goto einval; |
6b899c4e | 336 | |
1da177e4 | 337 | if (test_bit(Magic, &e->flags)) { |
6b899c4e MF |
338 | /* Handle the 'M' (magic) format. */ |
339 | char *s; | |
340 | ||
341 | /* Parse the 'offset' field. */ | |
342 | s = strchr(p, del); | |
1da177e4 | 343 | if (!s) |
e6084d4a | 344 | goto einval; |
5cc41e09 TLSC |
345 | *s = '\0'; |
346 | if (p != s) { | |
347 | int r = kstrtoint(p, 10, &e->offset); | |
348 | if (r != 0 || e->offset < 0) | |
349 | goto einval; | |
350 | } | |
351 | p = s; | |
1da177e4 | 352 | if (*p++) |
e6084d4a | 353 | goto einval; |
6b899c4e MF |
354 | pr_debug("register: offset: %#x\n", e->offset); |
355 | ||
356 | /* Parse the 'magic' field. */ | |
1da177e4 LT |
357 | e->magic = p; |
358 | p = scanarg(p, del); | |
359 | if (!p) | |
e6084d4a | 360 | goto einval; |
7d65cf10 | 361 | if (!e->magic[0]) |
e6084d4a | 362 | goto einval; |
6b899c4e MF |
363 | if (USE_DEBUG) |
364 | print_hex_dump_bytes( | |
365 | KBUILD_MODNAME ": register: magic[raw]: ", | |
366 | DUMP_PREFIX_NONE, e->magic, p - e->magic); | |
367 | ||
368 | /* Parse the 'mask' field. */ | |
1da177e4 LT |
369 | e->mask = p; |
370 | p = scanarg(p, del); | |
371 | if (!p) | |
e6084d4a | 372 | goto einval; |
7d65cf10 | 373 | if (!e->mask[0]) { |
1da177e4 | 374 | e->mask = NULL; |
6b899c4e MF |
375 | pr_debug("register: mask[raw]: none\n"); |
376 | } else if (USE_DEBUG) | |
377 | print_hex_dump_bytes( | |
378 | KBUILD_MODNAME ": register: mask[raw]: ", | |
379 | DUMP_PREFIX_NONE, e->mask, p - e->mask); | |
380 | ||
381 | /* | |
382 | * Decode the magic & mask fields. | |
383 | * Note: while we might have accepted embedded NUL bytes from | |
384 | * above, the unescape helpers here will stop at the first one | |
385 | * it encounters. | |
386 | */ | |
8d82e180 AS |
387 | e->size = string_unescape_inplace(e->magic, UNESCAPE_HEX); |
388 | if (e->mask && | |
389 | string_unescape_inplace(e->mask, UNESCAPE_HEX) != e->size) | |
e6084d4a | 390 | goto einval; |
5cc41e09 TLSC |
391 | if (e->size > BINPRM_BUF_SIZE || |
392 | BINPRM_BUF_SIZE - e->size < e->offset) | |
e6084d4a | 393 | goto einval; |
6b899c4e MF |
394 | pr_debug("register: magic/mask length: %i\n", e->size); |
395 | if (USE_DEBUG) { | |
396 | print_hex_dump_bytes( | |
397 | KBUILD_MODNAME ": register: magic[decoded]: ", | |
398 | DUMP_PREFIX_NONE, e->magic, e->size); | |
399 | ||
400 | if (e->mask) { | |
401 | int i; | |
f7e1ad1a | 402 | char *masked = kmalloc(e->size, GFP_KERNEL); |
6b899c4e MF |
403 | |
404 | print_hex_dump_bytes( | |
405 | KBUILD_MODNAME ": register: mask[decoded]: ", | |
406 | DUMP_PREFIX_NONE, e->mask, e->size); | |
407 | ||
408 | if (masked) { | |
409 | for (i = 0; i < e->size; ++i) | |
410 | masked[i] = e->magic[i] & e->mask[i]; | |
411 | print_hex_dump_bytes( | |
412 | KBUILD_MODNAME ": register: magic[masked]: ", | |
413 | DUMP_PREFIX_NONE, masked, e->size); | |
414 | ||
415 | kfree(masked); | |
416 | } | |
417 | } | |
418 | } | |
1da177e4 | 419 | } else { |
6b899c4e MF |
420 | /* Handle the 'E' (extension) format. */ |
421 | ||
422 | /* Skip the 'offset' field. */ | |
1da177e4 LT |
423 | p = strchr(p, del); |
424 | if (!p) | |
e6084d4a | 425 | goto einval; |
1da177e4 | 426 | *p++ = '\0'; |
6b899c4e MF |
427 | |
428 | /* Parse the 'magic' field. */ | |
1da177e4 LT |
429 | e->magic = p; |
430 | p = strchr(p, del); | |
431 | if (!p) | |
e6084d4a | 432 | goto einval; |
1da177e4 LT |
433 | *p++ = '\0'; |
434 | if (!e->magic[0] || strchr(e->magic, '/')) | |
e6084d4a | 435 | goto einval; |
6b899c4e MF |
436 | pr_debug("register: extension: {%s}\n", e->magic); |
437 | ||
438 | /* Skip the 'mask' field. */ | |
1da177e4 LT |
439 | p = strchr(p, del); |
440 | if (!p) | |
e6084d4a | 441 | goto einval; |
1da177e4 LT |
442 | *p++ = '\0'; |
443 | } | |
6b899c4e MF |
444 | |
445 | /* Parse the 'interpreter' field. */ | |
1da177e4 LT |
446 | e->interpreter = p; |
447 | p = strchr(p, del); | |
448 | if (!p) | |
e6084d4a | 449 | goto einval; |
1da177e4 LT |
450 | *p++ = '\0'; |
451 | if (!e->interpreter[0]) | |
e6084d4a | 452 | goto einval; |
6b899c4e | 453 | pr_debug("register: interpreter: {%s}\n", e->interpreter); |
1da177e4 | 454 | |
6b899c4e | 455 | /* Parse the 'flags' field. */ |
e6084d4a | 456 | p = check_special_flags(p, e); |
1da177e4 LT |
457 | if (*p == '\n') |
458 | p++; | |
459 | if (p != buf + count) | |
e6084d4a MF |
460 | goto einval; |
461 | ||
1da177e4 LT |
462 | return e; |
463 | ||
464 | out: | |
465 | return ERR_PTR(err); | |
466 | ||
e6084d4a | 467 | efault: |
1da177e4 LT |
468 | kfree(e); |
469 | return ERR_PTR(-EFAULT); | |
e6084d4a | 470 | einval: |
1da177e4 LT |
471 | kfree(e); |
472 | return ERR_PTR(-EINVAL); | |
473 | } | |
474 | ||
475 | /* | |
476 | * Set status of entry/binfmt_misc: | |
477 | * '1' enables, '0' disables and '-1' clears entry/binfmt_misc | |
478 | */ | |
479 | static int parse_command(const char __user *buffer, size_t count) | |
480 | { | |
481 | char s[4]; | |
482 | ||
1da177e4 LT |
483 | if (count > 3) |
484 | return -EINVAL; | |
485 | if (copy_from_user(s, buffer, count)) | |
486 | return -EFAULT; | |
de8288b1 AB |
487 | if (!count) |
488 | return 0; | |
e6084d4a | 489 | if (s[count - 1] == '\n') |
1da177e4 LT |
490 | count--; |
491 | if (count == 1 && s[0] == '0') | |
492 | return 1; | |
493 | if (count == 1 && s[0] == '1') | |
494 | return 2; | |
495 | if (count == 2 && s[0] == '-' && s[1] == '1') | |
496 | return 3; | |
497 | return -EINVAL; | |
498 | } | |
499 | ||
500 | /* generic stuff */ | |
501 | ||
502 | static void entry_status(Node *e, char *page) | |
503 | { | |
6ceafb88 RV |
504 | char *dp = page; |
505 | const char *status = "disabled"; | |
1da177e4 LT |
506 | |
507 | if (test_bit(Enabled, &e->flags)) | |
508 | status = "enabled"; | |
509 | ||
510 | if (!VERBOSE_STATUS) { | |
511 | sprintf(page, "%s\n", status); | |
512 | return; | |
513 | } | |
514 | ||
6ceafb88 | 515 | dp += sprintf(dp, "%s\ninterpreter %s\n", status, e->interpreter); |
1da177e4 LT |
516 | |
517 | /* print the special flags */ | |
6ceafb88 | 518 | dp += sprintf(dp, "flags: "); |
e6084d4a MF |
519 | if (e->flags & MISC_FMT_PRESERVE_ARGV0) |
520 | *dp++ = 'P'; | |
521 | if (e->flags & MISC_FMT_OPEN_BINARY) | |
522 | *dp++ = 'O'; | |
523 | if (e->flags & MISC_FMT_CREDENTIALS) | |
524 | *dp++ = 'C'; | |
948b701a JB |
525 | if (e->flags & MISC_FMT_OPEN_FILE) |
526 | *dp++ = 'F'; | |
e6084d4a | 527 | *dp++ = '\n'; |
1da177e4 LT |
528 | |
529 | if (!test_bit(Magic, &e->flags)) { | |
530 | sprintf(dp, "extension .%s\n", e->magic); | |
531 | } else { | |
6ceafb88 RV |
532 | dp += sprintf(dp, "offset %i\nmagic ", e->offset); |
533 | dp = bin2hex(dp, e->magic, e->size); | |
1da177e4 | 534 | if (e->mask) { |
6ceafb88 RV |
535 | dp += sprintf(dp, "\nmask "); |
536 | dp = bin2hex(dp, e->mask, e->size); | |
1da177e4 LT |
537 | } |
538 | *dp++ = '\n'; | |
539 | *dp = '\0'; | |
540 | } | |
541 | } | |
542 | ||
543 | static struct inode *bm_get_inode(struct super_block *sb, int mode) | |
544 | { | |
e6084d4a | 545 | struct inode *inode = new_inode(sb); |
1da177e4 LT |
546 | |
547 | if (inode) { | |
85fe4025 | 548 | inode->i_ino = get_next_ino(); |
1da177e4 | 549 | inode->i_mode = mode; |
1da177e4 | 550 | inode->i_atime = inode->i_mtime = inode->i_ctime = |
c2050a45 | 551 | current_time(inode); |
1da177e4 LT |
552 | } |
553 | return inode; | |
554 | } | |
555 | ||
b57922d9 | 556 | static void bm_evict_inode(struct inode *inode) |
1da177e4 | 557 | { |
83f91827 ON |
558 | Node *e = inode->i_private; |
559 | ||
7e866006 | 560 | if (e && e->flags & MISC_FMT_OPEN_FILE) |
83f91827 ON |
561 | filp_close(e->interp_file, NULL); |
562 | ||
dbd5768f | 563 | clear_inode(inode); |
83f91827 | 564 | kfree(e); |
1da177e4 LT |
565 | } |
566 | ||
567 | static void kill_node(Node *e) | |
568 | { | |
569 | struct dentry *dentry; | |
570 | ||
571 | write_lock(&entries_lock); | |
baba1b29 | 572 | list_del_init(&e->list); |
1da177e4 LT |
573 | write_unlock(&entries_lock); |
574 | ||
baba1b29 ON |
575 | dentry = e->dentry; |
576 | drop_nlink(d_inode(dentry)); | |
577 | d_drop(dentry); | |
578 | dput(dentry); | |
579 | simple_release_fs(&bm_mnt, &entry_count); | |
1da177e4 LT |
580 | } |
581 | ||
582 | /* /<entry> */ | |
583 | ||
584 | static ssize_t | |
e6084d4a | 585 | bm_entry_read(struct file *file, char __user *buf, size_t nbytes, loff_t *ppos) |
1da177e4 | 586 | { |
496ad9aa | 587 | Node *e = file_inode(file)->i_private; |
1da177e4 LT |
588 | ssize_t res; |
589 | char *page; | |
1da177e4 | 590 | |
e6084d4a MF |
591 | page = (char *) __get_free_page(GFP_KERNEL); |
592 | if (!page) | |
1da177e4 LT |
593 | return -ENOMEM; |
594 | ||
595 | entry_status(e, page); | |
1da177e4 | 596 | |
6e2c10a1 AM |
597 | res = simple_read_from_buffer(buf, nbytes, ppos, page, strlen(page)); |
598 | ||
1da177e4 LT |
599 | free_page((unsigned long) page); |
600 | return res; | |
601 | } | |
602 | ||
603 | static ssize_t bm_entry_write(struct file *file, const char __user *buffer, | |
604 | size_t count, loff_t *ppos) | |
605 | { | |
606 | struct dentry *root; | |
496ad9aa | 607 | Node *e = file_inode(file)->i_private; |
1da177e4 LT |
608 | int res = parse_command(buffer, count); |
609 | ||
610 | switch (res) { | |
e6084d4a MF |
611 | case 1: |
612 | /* Disable this handler. */ | |
613 | clear_bit(Enabled, &e->flags); | |
614 | break; | |
615 | case 2: | |
616 | /* Enable this handler. */ | |
617 | set_bit(Enabled, &e->flags); | |
618 | break; | |
619 | case 3: | |
620 | /* Delete this handler. */ | |
ea7d4c04 | 621 | root = file_inode(file)->i_sb->s_root; |
5955102c | 622 | inode_lock(d_inode(root)); |
1da177e4 | 623 | |
baba1b29 ON |
624 | if (!list_empty(&e->list)) |
625 | kill_node(e); | |
1da177e4 | 626 | |
5955102c | 627 | inode_unlock(d_inode(root)); |
e6084d4a MF |
628 | break; |
629 | default: | |
630 | return res; | |
1da177e4 | 631 | } |
e6084d4a | 632 | |
1da177e4 LT |
633 | return count; |
634 | } | |
635 | ||
4b6f5d20 | 636 | static const struct file_operations bm_entry_operations = { |
1da177e4 LT |
637 | .read = bm_entry_read, |
638 | .write = bm_entry_write, | |
6038f373 | 639 | .llseek = default_llseek, |
1da177e4 LT |
640 | }; |
641 | ||
642 | /* /register */ | |
643 | ||
644 | static ssize_t bm_register_write(struct file *file, const char __user *buffer, | |
645 | size_t count, loff_t *ppos) | |
646 | { | |
647 | Node *e; | |
648 | struct inode *inode; | |
ea7d4c04 AV |
649 | struct super_block *sb = file_inode(file)->i_sb; |
650 | struct dentry *root = sb->s_root, *dentry; | |
1da177e4 | 651 | int err = 0; |
e7850f4d | 652 | struct file *f = NULL; |
1da177e4 LT |
653 | |
654 | e = create_entry(buffer, count); | |
655 | ||
656 | if (IS_ERR(e)) | |
657 | return PTR_ERR(e); | |
658 | ||
e7850f4d LR |
659 | if (e->flags & MISC_FMT_OPEN_FILE) { |
660 | f = open_exec(e->interpreter); | |
661 | if (IS_ERR(f)) { | |
662 | pr_notice("register: failed to install interpreter file %s\n", | |
663 | e->interpreter); | |
664 | kfree(e); | |
665 | return PTR_ERR(f); | |
666 | } | |
667 | e->interp_file = f; | |
668 | } | |
669 | ||
5955102c | 670 | inode_lock(d_inode(root)); |
1da177e4 LT |
671 | dentry = lookup_one_len(e->name, root, strlen(e->name)); |
672 | err = PTR_ERR(dentry); | |
673 | if (IS_ERR(dentry)) | |
674 | goto out; | |
675 | ||
676 | err = -EEXIST; | |
75c3cfa8 | 677 | if (d_really_is_positive(dentry)) |
1da177e4 LT |
678 | goto out2; |
679 | ||
680 | inode = bm_get_inode(sb, S_IFREG | 0644); | |
681 | ||
682 | err = -ENOMEM; | |
683 | if (!inode) | |
684 | goto out2; | |
685 | ||
1f5ce9e9 | 686 | err = simple_pin_fs(&bm_fs_type, &bm_mnt, &entry_count); |
1da177e4 LT |
687 | if (err) { |
688 | iput(inode); | |
689 | inode = NULL; | |
690 | goto out2; | |
691 | } | |
692 | ||
693 | e->dentry = dget(dentry); | |
8e18e294 | 694 | inode->i_private = e; |
1da177e4 LT |
695 | inode->i_fop = &bm_entry_operations; |
696 | ||
697 | d_instantiate(dentry, inode); | |
698 | write_lock(&entries_lock); | |
699 | list_add(&e->list, &entries); | |
700 | write_unlock(&entries_lock); | |
701 | ||
702 | err = 0; | |
703 | out2: | |
704 | dput(dentry); | |
705 | out: | |
5955102c | 706 | inode_unlock(d_inode(root)); |
1da177e4 LT |
707 | |
708 | if (err) { | |
e7850f4d LR |
709 | if (f) |
710 | filp_close(f, NULL); | |
1da177e4 | 711 | kfree(e); |
948b701a | 712 | return err; |
1da177e4 LT |
713 | } |
714 | return count; | |
715 | } | |
716 | ||
4b6f5d20 | 717 | static const struct file_operations bm_register_operations = { |
1da177e4 | 718 | .write = bm_register_write, |
6038f373 | 719 | .llseek = noop_llseek, |
1da177e4 LT |
720 | }; |
721 | ||
722 | /* /status */ | |
723 | ||
724 | static ssize_t | |
725 | bm_status_read(struct file *file, char __user *buf, size_t nbytes, loff_t *ppos) | |
726 | { | |
87113e80 | 727 | char *s = enabled ? "enabled\n" : "disabled\n"; |
1da177e4 | 728 | |
92f4c701 | 729 | return simple_read_from_buffer(buf, nbytes, ppos, s, strlen(s)); |
1da177e4 LT |
730 | } |
731 | ||
e6084d4a | 732 | static ssize_t bm_status_write(struct file *file, const char __user *buffer, |
1da177e4 LT |
733 | size_t count, loff_t *ppos) |
734 | { | |
735 | int res = parse_command(buffer, count); | |
736 | struct dentry *root; | |
737 | ||
738 | switch (res) { | |
e6084d4a MF |
739 | case 1: |
740 | /* Disable all handlers. */ | |
741 | enabled = 0; | |
742 | break; | |
743 | case 2: | |
744 | /* Enable all handlers. */ | |
745 | enabled = 1; | |
746 | break; | |
747 | case 3: | |
748 | /* Delete all handlers. */ | |
ea7d4c04 | 749 | root = file_inode(file)->i_sb->s_root; |
5955102c | 750 | inode_lock(d_inode(root)); |
1da177e4 | 751 | |
e6084d4a | 752 | while (!list_empty(&entries)) |
baba1b29 | 753 | kill_node(list_first_entry(&entries, Node, list)); |
1da177e4 | 754 | |
5955102c | 755 | inode_unlock(d_inode(root)); |
e6084d4a MF |
756 | break; |
757 | default: | |
758 | return res; | |
1da177e4 | 759 | } |
e6084d4a | 760 | |
1da177e4 LT |
761 | return count; |
762 | } | |
763 | ||
4b6f5d20 | 764 | static const struct file_operations bm_status_operations = { |
1da177e4 LT |
765 | .read = bm_status_read, |
766 | .write = bm_status_write, | |
6038f373 | 767 | .llseek = default_llseek, |
1da177e4 LT |
768 | }; |
769 | ||
770 | /* Superblock handling */ | |
771 | ||
ee9b6d61 | 772 | static const struct super_operations s_ops = { |
1da177e4 | 773 | .statfs = simple_statfs, |
b57922d9 | 774 | .evict_inode = bm_evict_inode, |
1da177e4 LT |
775 | }; |
776 | ||
bc99a664 | 777 | static int bm_fill_super(struct super_block *sb, struct fs_context *fc) |
1da177e4 | 778 | { |
e6084d4a | 779 | int err; |
cda37124 | 780 | static const struct tree_descr bm_files[] = { |
1a1c9bb4 JL |
781 | [2] = {"status", &bm_status_operations, S_IWUSR|S_IRUGO}, |
782 | [3] = {"register", &bm_register_operations, S_IWUSR}, | |
1da177e4 LT |
783 | /* last one */ {""} |
784 | }; | |
e6084d4a MF |
785 | |
786 | err = simple_fill_super(sb, BINFMTFS_MAGIC, bm_files); | |
1da177e4 LT |
787 | if (!err) |
788 | sb->s_op = &s_ops; | |
789 | return err; | |
790 | } | |
791 | ||
bc99a664 | 792 | static int bm_get_tree(struct fs_context *fc) |
1da177e4 | 793 | { |
bc99a664 DH |
794 | return get_tree_single(fc, bm_fill_super); |
795 | } | |
796 | ||
797 | static const struct fs_context_operations bm_context_ops = { | |
798 | .get_tree = bm_get_tree, | |
799 | }; | |
800 | ||
801 | static int bm_init_fs_context(struct fs_context *fc) | |
802 | { | |
803 | fc->ops = &bm_context_ops; | |
804 | return 0; | |
1da177e4 LT |
805 | } |
806 | ||
807 | static struct linux_binfmt misc_format = { | |
808 | .module = THIS_MODULE, | |
809 | .load_binary = load_misc_binary, | |
810 | }; | |
811 | ||
812 | static struct file_system_type bm_fs_type = { | |
813 | .owner = THIS_MODULE, | |
814 | .name = "binfmt_misc", | |
bc99a664 | 815 | .init_fs_context = bm_init_fs_context, |
1da177e4 LT |
816 | .kill_sb = kill_litter_super, |
817 | }; | |
7f78e035 | 818 | MODULE_ALIAS_FS("binfmt_misc"); |
1da177e4 LT |
819 | |
820 | static int __init init_misc_binfmt(void) | |
821 | { | |
822 | int err = register_filesystem(&bm_fs_type); | |
8fc3dc5a AV |
823 | if (!err) |
824 | insert_binfmt(&misc_format); | |
b42bc9a3 | 825 | return err; |
1da177e4 LT |
826 | } |
827 | ||
828 | static void __exit exit_misc_binfmt(void) | |
829 | { | |
830 | unregister_binfmt(&misc_format); | |
831 | unregister_filesystem(&bm_fs_type); | |
832 | } | |
833 | ||
834 | core_initcall(init_misc_binfmt); | |
835 | module_exit(exit_misc_binfmt); | |
836 | MODULE_LICENSE("GPL"); |