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 LT |
136 | int retval; |
137 | int fd_binary = -1; | |
1da177e4 LT |
138 | |
139 | retval = -ENOEXEC; | |
140 | if (!enabled) | |
43a4f261 | 141 | return retval; |
1da177e4 LT |
142 | |
143 | /* to keep locking time low, we copy the interpreter string */ | |
144 | read_lock(&entries_lock); | |
145 | fmt = check_file(bprm); | |
50097f74 | 146 | if (fmt) |
43a4f261 | 147 | dget(fmt->dentry); |
1da177e4 LT |
148 | read_unlock(&entries_lock); |
149 | if (!fmt) | |
43a4f261 | 150 | return retval; |
1da177e4 | 151 | |
51f39a1f | 152 | /* Need to be able to load the file after exec */ |
43a4f261 | 153 | retval = -ENOENT; |
51f39a1f | 154 | if (bprm->interp_flags & BINPRM_FLAGS_PATH_INACCESSIBLE) |
43a4f261 | 155 | goto ret; |
51f39a1f | 156 | |
1da177e4 | 157 | if (!(fmt->flags & MISC_FMT_PRESERVE_ARGV0)) { |
b6a2fea3 OW |
158 | retval = remove_arg_zero(bprm); |
159 | if (retval) | |
e6084d4a | 160 | goto ret; |
1da177e4 LT |
161 | } |
162 | ||
163 | if (fmt->flags & MISC_FMT_OPEN_BINARY) { | |
164 | ||
1da177e4 LT |
165 | /* if the binary should be opened on behalf of the |
166 | * interpreter than keep it open and assign descriptor | |
e6084d4a MF |
167 | * to it |
168 | */ | |
c6cb898b | 169 | fd_binary = get_unused_fd_flags(0); |
e6084d4a MF |
170 | if (fd_binary < 0) { |
171 | retval = fd_binary; | |
172 | goto ret; | |
173 | } | |
174 | fd_install(fd_binary, bprm->file); | |
1da177e4 LT |
175 | |
176 | /* if the binary is not readable than enforce mm->dumpable=0 | |
177 | regardless of the interpreter's permissions */ | |
1b5d783c | 178 | would_dump(bprm, bprm->file); |
1da177e4 LT |
179 | |
180 | allow_write_access(bprm->file); | |
181 | bprm->file = NULL; | |
182 | ||
183 | /* mark the bprm that fd should be passed to interp */ | |
184 | bprm->interp_flags |= BINPRM_FLAGS_EXECFD; | |
185 | bprm->interp_data = fd_binary; | |
186 | ||
e6084d4a MF |
187 | } else { |
188 | allow_write_access(bprm->file); | |
189 | fput(bprm->file); | |
190 | bprm->file = NULL; | |
191 | } | |
1da177e4 | 192 | /* make argv[1] be the path to the binary */ |
e6084d4a | 193 | retval = copy_strings_kernel(1, &bprm->interp, bprm); |
1da177e4 | 194 | if (retval < 0) |
e6084d4a | 195 | goto error; |
1da177e4 LT |
196 | bprm->argc++; |
197 | ||
198 | /* add the interp as argv[0] */ | |
50097f74 | 199 | retval = copy_strings_kernel(1, &fmt->interpreter, bprm); |
1da177e4 | 200 | if (retval < 0) |
e6084d4a MF |
201 | goto error; |
202 | bprm->argc++; | |
1da177e4 | 203 | |
b66c5984 | 204 | /* Update interp in case binfmt_script needs it. */ |
50097f74 | 205 | retval = bprm_change_interp(fmt->interpreter, bprm); |
b66c5984 | 206 | if (retval < 0) |
e6084d4a | 207 | goto error; |
1da177e4 | 208 | |
eb23aa03 | 209 | if (fmt->flags & MISC_FMT_OPEN_FILE) { |
19f391eb | 210 | interp_file = file_clone_open(fmt->interp_file); |
948b701a JB |
211 | if (!IS_ERR(interp_file)) |
212 | deny_write_access(interp_file); | |
213 | } else { | |
50097f74 | 214 | interp_file = open_exec(fmt->interpreter); |
948b701a | 215 | } |
e6084d4a MF |
216 | retval = PTR_ERR(interp_file); |
217 | if (IS_ERR(interp_file)) | |
218 | goto error; | |
1da177e4 LT |
219 | |
220 | bprm->file = interp_file; | |
a16b3357 EB |
221 | if (fmt->flags & MISC_FMT_CREDENTIALS) |
222 | bprm->preserve_creds = 1; | |
1da177e4 | 223 | |
3c456bfc | 224 | retval = search_binary_handler(bprm); |
1da177e4 | 225 | if (retval < 0) |
e6084d4a | 226 | goto error; |
1da177e4 | 227 | |
e6084d4a | 228 | ret: |
43a4f261 | 229 | dput(fmt->dentry); |
1da177e4 | 230 | return retval; |
e6084d4a | 231 | error: |
1da177e4 | 232 | if (fd_binary > 0) |
2ca2a09d | 233 | ksys_close(fd_binary); |
1da177e4 LT |
234 | bprm->interp_flags = 0; |
235 | bprm->interp_data = 0; | |
e6084d4a | 236 | goto ret; |
1da177e4 LT |
237 | } |
238 | ||
239 | /* Command parsers */ | |
240 | ||
241 | /* | |
242 | * parses and copies one argument enclosed in del from *sp to *dp, | |
243 | * recognising the \x special. | |
244 | * returns pointer to the copied argument or NULL in case of an | |
245 | * error (and sets err) or null argument length. | |
246 | */ | |
247 | static char *scanarg(char *s, char del) | |
248 | { | |
249 | char c; | |
250 | ||
251 | while ((c = *s++) != del) { | |
252 | if (c == '\\' && *s == 'x') { | |
253 | s++; | |
254 | if (!isxdigit(*s++)) | |
255 | return NULL; | |
256 | if (!isxdigit(*s++)) | |
257 | return NULL; | |
258 | } | |
259 | } | |
7d65cf10 | 260 | s[-1] ='\0'; |
1da177e4 LT |
261 | return s; |
262 | } | |
263 | ||
e6084d4a | 264 | static char *check_special_flags(char *sfs, Node *e) |
1da177e4 | 265 | { |
e6084d4a | 266 | char *p = sfs; |
1da177e4 LT |
267 | int cont = 1; |
268 | ||
269 | /* special flags */ | |
270 | while (cont) { | |
271 | switch (*p) { | |
e6084d4a MF |
272 | case 'P': |
273 | pr_debug("register: flag: P (preserve argv0)\n"); | |
274 | p++; | |
275 | e->flags |= MISC_FMT_PRESERVE_ARGV0; | |
276 | break; | |
277 | case 'O': | |
278 | pr_debug("register: flag: O (open binary)\n"); | |
279 | p++; | |
280 | e->flags |= MISC_FMT_OPEN_BINARY; | |
281 | break; | |
282 | case 'C': | |
283 | pr_debug("register: flag: C (preserve creds)\n"); | |
284 | p++; | |
285 | /* this flags also implies the | |
286 | open-binary flag */ | |
287 | e->flags |= (MISC_FMT_CREDENTIALS | | |
288 | MISC_FMT_OPEN_BINARY); | |
289 | break; | |
948b701a JB |
290 | case 'F': |
291 | pr_debug("register: flag: F: open interpreter file now\n"); | |
292 | p++; | |
293 | e->flags |= MISC_FMT_OPEN_FILE; | |
294 | break; | |
e6084d4a MF |
295 | default: |
296 | cont = 0; | |
1da177e4 LT |
297 | } |
298 | } | |
299 | ||
300 | return p; | |
301 | } | |
e6084d4a | 302 | |
1da177e4 LT |
303 | /* |
304 | * This registers a new binary format, it recognises the syntax | |
305 | * ':name:type:offset:magic:mask:interpreter:flags' | |
306 | * where the ':' is the IFS, that can be chosen with the first char | |
307 | */ | |
308 | static Node *create_entry(const char __user *buffer, size_t count) | |
309 | { | |
310 | Node *e; | |
311 | int memsize, err; | |
312 | char *buf, *p; | |
313 | char del; | |
314 | ||
6b899c4e MF |
315 | pr_debug("register: received %zu bytes\n", count); |
316 | ||
1da177e4 LT |
317 | /* some sanity checks */ |
318 | err = -EINVAL; | |
bbaecc08 | 319 | if ((count < 11) || (count > MAX_REGISTER_LENGTH)) |
1da177e4 LT |
320 | goto out; |
321 | ||
322 | err = -ENOMEM; | |
323 | memsize = sizeof(Node) + count + 8; | |
f7e1ad1a | 324 | e = kmalloc(memsize, GFP_KERNEL); |
1da177e4 LT |
325 | if (!e) |
326 | goto out; | |
327 | ||
328 | p = buf = (char *)e + sizeof(Node); | |
329 | ||
330 | memset(e, 0, sizeof(Node)); | |
331 | if (copy_from_user(buf, buffer, count)) | |
e6084d4a | 332 | goto efault; |
1da177e4 LT |
333 | |
334 | del = *p++; /* delimeter */ | |
335 | ||
6b899c4e MF |
336 | pr_debug("register: delim: %#x {%c}\n", del, del); |
337 | ||
338 | /* Pad the buffer with the delim to simplify parsing below. */ | |
e6084d4a | 339 | memset(buf + count, del, 8); |
1da177e4 | 340 | |
6b899c4e | 341 | /* Parse the 'name' field. */ |
1da177e4 LT |
342 | e->name = p; |
343 | p = strchr(p, del); | |
344 | if (!p) | |
e6084d4a | 345 | goto einval; |
1da177e4 LT |
346 | *p++ = '\0'; |
347 | if (!e->name[0] || | |
348 | !strcmp(e->name, ".") || | |
349 | !strcmp(e->name, "..") || | |
350 | strchr(e->name, '/')) | |
e6084d4a | 351 | goto einval; |
6b899c4e MF |
352 | |
353 | pr_debug("register: name: {%s}\n", e->name); | |
354 | ||
355 | /* Parse the 'type' field. */ | |
1da177e4 | 356 | switch (*p++) { |
6b899c4e MF |
357 | case 'E': |
358 | pr_debug("register: type: E (extension)\n"); | |
359 | e->flags = 1 << Enabled; | |
360 | break; | |
361 | case 'M': | |
362 | pr_debug("register: type: M (magic)\n"); | |
363 | e->flags = (1 << Enabled) | (1 << Magic); | |
364 | break; | |
365 | default: | |
e6084d4a | 366 | goto einval; |
1da177e4 LT |
367 | } |
368 | if (*p++ != del) | |
e6084d4a | 369 | goto einval; |
6b899c4e | 370 | |
1da177e4 | 371 | if (test_bit(Magic, &e->flags)) { |
6b899c4e MF |
372 | /* Handle the 'M' (magic) format. */ |
373 | char *s; | |
374 | ||
375 | /* Parse the 'offset' field. */ | |
376 | s = strchr(p, del); | |
1da177e4 | 377 | if (!s) |
e6084d4a | 378 | goto einval; |
5cc41e09 TLSC |
379 | *s = '\0'; |
380 | if (p != s) { | |
381 | int r = kstrtoint(p, 10, &e->offset); | |
382 | if (r != 0 || e->offset < 0) | |
383 | goto einval; | |
384 | } | |
385 | p = s; | |
1da177e4 | 386 | if (*p++) |
e6084d4a | 387 | goto einval; |
6b899c4e MF |
388 | pr_debug("register: offset: %#x\n", e->offset); |
389 | ||
390 | /* Parse the 'magic' field. */ | |
1da177e4 LT |
391 | e->magic = p; |
392 | p = scanarg(p, del); | |
393 | if (!p) | |
e6084d4a | 394 | goto einval; |
7d65cf10 | 395 | if (!e->magic[0]) |
e6084d4a | 396 | goto einval; |
6b899c4e MF |
397 | if (USE_DEBUG) |
398 | print_hex_dump_bytes( | |
399 | KBUILD_MODNAME ": register: magic[raw]: ", | |
400 | DUMP_PREFIX_NONE, e->magic, p - e->magic); | |
401 | ||
402 | /* Parse the 'mask' field. */ | |
1da177e4 LT |
403 | e->mask = p; |
404 | p = scanarg(p, del); | |
405 | if (!p) | |
e6084d4a | 406 | goto einval; |
7d65cf10 | 407 | if (!e->mask[0]) { |
1da177e4 | 408 | e->mask = NULL; |
6b899c4e MF |
409 | pr_debug("register: mask[raw]: none\n"); |
410 | } else if (USE_DEBUG) | |
411 | print_hex_dump_bytes( | |
412 | KBUILD_MODNAME ": register: mask[raw]: ", | |
413 | DUMP_PREFIX_NONE, e->mask, p - e->mask); | |
414 | ||
415 | /* | |
416 | * Decode the magic & mask fields. | |
417 | * Note: while we might have accepted embedded NUL bytes from | |
418 | * above, the unescape helpers here will stop at the first one | |
419 | * it encounters. | |
420 | */ | |
8d82e180 AS |
421 | e->size = string_unescape_inplace(e->magic, UNESCAPE_HEX); |
422 | if (e->mask && | |
423 | string_unescape_inplace(e->mask, UNESCAPE_HEX) != e->size) | |
e6084d4a | 424 | goto einval; |
5cc41e09 TLSC |
425 | if (e->size > BINPRM_BUF_SIZE || |
426 | BINPRM_BUF_SIZE - e->size < e->offset) | |
e6084d4a | 427 | goto einval; |
6b899c4e MF |
428 | pr_debug("register: magic/mask length: %i\n", e->size); |
429 | if (USE_DEBUG) { | |
430 | print_hex_dump_bytes( | |
431 | KBUILD_MODNAME ": register: magic[decoded]: ", | |
432 | DUMP_PREFIX_NONE, e->magic, e->size); | |
433 | ||
434 | if (e->mask) { | |
435 | int i; | |
f7e1ad1a | 436 | char *masked = kmalloc(e->size, GFP_KERNEL); |
6b899c4e MF |
437 | |
438 | print_hex_dump_bytes( | |
439 | KBUILD_MODNAME ": register: mask[decoded]: ", | |
440 | DUMP_PREFIX_NONE, e->mask, e->size); | |
441 | ||
442 | if (masked) { | |
443 | for (i = 0; i < e->size; ++i) | |
444 | masked[i] = e->magic[i] & e->mask[i]; | |
445 | print_hex_dump_bytes( | |
446 | KBUILD_MODNAME ": register: magic[masked]: ", | |
447 | DUMP_PREFIX_NONE, masked, e->size); | |
448 | ||
449 | kfree(masked); | |
450 | } | |
451 | } | |
452 | } | |
1da177e4 | 453 | } else { |
6b899c4e MF |
454 | /* Handle the 'E' (extension) format. */ |
455 | ||
456 | /* Skip the 'offset' field. */ | |
1da177e4 LT |
457 | p = strchr(p, del); |
458 | if (!p) | |
e6084d4a | 459 | goto einval; |
1da177e4 | 460 | *p++ = '\0'; |
6b899c4e MF |
461 | |
462 | /* Parse the 'magic' field. */ | |
1da177e4 LT |
463 | e->magic = p; |
464 | p = strchr(p, del); | |
465 | if (!p) | |
e6084d4a | 466 | goto einval; |
1da177e4 LT |
467 | *p++ = '\0'; |
468 | if (!e->magic[0] || strchr(e->magic, '/')) | |
e6084d4a | 469 | goto einval; |
6b899c4e MF |
470 | pr_debug("register: extension: {%s}\n", e->magic); |
471 | ||
472 | /* Skip the 'mask' field. */ | |
1da177e4 LT |
473 | p = strchr(p, del); |
474 | if (!p) | |
e6084d4a | 475 | goto einval; |
1da177e4 LT |
476 | *p++ = '\0'; |
477 | } | |
6b899c4e MF |
478 | |
479 | /* Parse the 'interpreter' field. */ | |
1da177e4 LT |
480 | e->interpreter = p; |
481 | p = strchr(p, del); | |
482 | if (!p) | |
e6084d4a | 483 | goto einval; |
1da177e4 LT |
484 | *p++ = '\0'; |
485 | if (!e->interpreter[0]) | |
e6084d4a | 486 | goto einval; |
6b899c4e | 487 | pr_debug("register: interpreter: {%s}\n", e->interpreter); |
1da177e4 | 488 | |
6b899c4e | 489 | /* Parse the 'flags' field. */ |
e6084d4a | 490 | p = check_special_flags(p, e); |
1da177e4 LT |
491 | if (*p == '\n') |
492 | p++; | |
493 | if (p != buf + count) | |
e6084d4a MF |
494 | goto einval; |
495 | ||
1da177e4 LT |
496 | return e; |
497 | ||
498 | out: | |
499 | return ERR_PTR(err); | |
500 | ||
e6084d4a | 501 | efault: |
1da177e4 LT |
502 | kfree(e); |
503 | return ERR_PTR(-EFAULT); | |
e6084d4a | 504 | einval: |
1da177e4 LT |
505 | kfree(e); |
506 | return ERR_PTR(-EINVAL); | |
507 | } | |
508 | ||
509 | /* | |
510 | * Set status of entry/binfmt_misc: | |
511 | * '1' enables, '0' disables and '-1' clears entry/binfmt_misc | |
512 | */ | |
513 | static int parse_command(const char __user *buffer, size_t count) | |
514 | { | |
515 | char s[4]; | |
516 | ||
1da177e4 LT |
517 | if (count > 3) |
518 | return -EINVAL; | |
519 | if (copy_from_user(s, buffer, count)) | |
520 | return -EFAULT; | |
de8288b1 AB |
521 | if (!count) |
522 | return 0; | |
e6084d4a | 523 | if (s[count - 1] == '\n') |
1da177e4 LT |
524 | count--; |
525 | if (count == 1 && s[0] == '0') | |
526 | return 1; | |
527 | if (count == 1 && s[0] == '1') | |
528 | return 2; | |
529 | if (count == 2 && s[0] == '-' && s[1] == '1') | |
530 | return 3; | |
531 | return -EINVAL; | |
532 | } | |
533 | ||
534 | /* generic stuff */ | |
535 | ||
536 | static void entry_status(Node *e, char *page) | |
537 | { | |
6ceafb88 RV |
538 | char *dp = page; |
539 | const char *status = "disabled"; | |
1da177e4 LT |
540 | |
541 | if (test_bit(Enabled, &e->flags)) | |
542 | status = "enabled"; | |
543 | ||
544 | if (!VERBOSE_STATUS) { | |
545 | sprintf(page, "%s\n", status); | |
546 | return; | |
547 | } | |
548 | ||
6ceafb88 | 549 | dp += sprintf(dp, "%s\ninterpreter %s\n", status, e->interpreter); |
1da177e4 LT |
550 | |
551 | /* print the special flags */ | |
6ceafb88 | 552 | dp += sprintf(dp, "flags: "); |
e6084d4a MF |
553 | if (e->flags & MISC_FMT_PRESERVE_ARGV0) |
554 | *dp++ = 'P'; | |
555 | if (e->flags & MISC_FMT_OPEN_BINARY) | |
556 | *dp++ = 'O'; | |
557 | if (e->flags & MISC_FMT_CREDENTIALS) | |
558 | *dp++ = 'C'; | |
948b701a JB |
559 | if (e->flags & MISC_FMT_OPEN_FILE) |
560 | *dp++ = 'F'; | |
e6084d4a | 561 | *dp++ = '\n'; |
1da177e4 LT |
562 | |
563 | if (!test_bit(Magic, &e->flags)) { | |
564 | sprintf(dp, "extension .%s\n", e->magic); | |
565 | } else { | |
6ceafb88 RV |
566 | dp += sprintf(dp, "offset %i\nmagic ", e->offset); |
567 | dp = bin2hex(dp, e->magic, e->size); | |
1da177e4 | 568 | if (e->mask) { |
6ceafb88 RV |
569 | dp += sprintf(dp, "\nmask "); |
570 | dp = bin2hex(dp, e->mask, e->size); | |
1da177e4 LT |
571 | } |
572 | *dp++ = '\n'; | |
573 | *dp = '\0'; | |
574 | } | |
575 | } | |
576 | ||
577 | static struct inode *bm_get_inode(struct super_block *sb, int mode) | |
578 | { | |
e6084d4a | 579 | struct inode *inode = new_inode(sb); |
1da177e4 LT |
580 | |
581 | if (inode) { | |
85fe4025 | 582 | inode->i_ino = get_next_ino(); |
1da177e4 | 583 | inode->i_mode = mode; |
1da177e4 | 584 | inode->i_atime = inode->i_mtime = inode->i_ctime = |
c2050a45 | 585 | current_time(inode); |
1da177e4 LT |
586 | } |
587 | return inode; | |
588 | } | |
589 | ||
b57922d9 | 590 | static void bm_evict_inode(struct inode *inode) |
1da177e4 | 591 | { |
83f91827 ON |
592 | Node *e = inode->i_private; |
593 | ||
7e866006 | 594 | if (e && e->flags & MISC_FMT_OPEN_FILE) |
83f91827 ON |
595 | filp_close(e->interp_file, NULL); |
596 | ||
dbd5768f | 597 | clear_inode(inode); |
83f91827 | 598 | kfree(e); |
1da177e4 LT |
599 | } |
600 | ||
601 | static void kill_node(Node *e) | |
602 | { | |
603 | struct dentry *dentry; | |
604 | ||
605 | write_lock(&entries_lock); | |
baba1b29 | 606 | list_del_init(&e->list); |
1da177e4 LT |
607 | write_unlock(&entries_lock); |
608 | ||
baba1b29 ON |
609 | dentry = e->dentry; |
610 | drop_nlink(d_inode(dentry)); | |
611 | d_drop(dentry); | |
612 | dput(dentry); | |
613 | simple_release_fs(&bm_mnt, &entry_count); | |
1da177e4 LT |
614 | } |
615 | ||
616 | /* /<entry> */ | |
617 | ||
618 | static ssize_t | |
e6084d4a | 619 | bm_entry_read(struct file *file, char __user *buf, size_t nbytes, loff_t *ppos) |
1da177e4 | 620 | { |
496ad9aa | 621 | Node *e = file_inode(file)->i_private; |
1da177e4 LT |
622 | ssize_t res; |
623 | char *page; | |
1da177e4 | 624 | |
e6084d4a MF |
625 | page = (char *) __get_free_page(GFP_KERNEL); |
626 | if (!page) | |
1da177e4 LT |
627 | return -ENOMEM; |
628 | ||
629 | entry_status(e, page); | |
1da177e4 | 630 | |
6e2c10a1 AM |
631 | res = simple_read_from_buffer(buf, nbytes, ppos, page, strlen(page)); |
632 | ||
1da177e4 LT |
633 | free_page((unsigned long) page); |
634 | return res; | |
635 | } | |
636 | ||
637 | static ssize_t bm_entry_write(struct file *file, const char __user *buffer, | |
638 | size_t count, loff_t *ppos) | |
639 | { | |
640 | struct dentry *root; | |
496ad9aa | 641 | Node *e = file_inode(file)->i_private; |
1da177e4 LT |
642 | int res = parse_command(buffer, count); |
643 | ||
644 | switch (res) { | |
e6084d4a MF |
645 | case 1: |
646 | /* Disable this handler. */ | |
647 | clear_bit(Enabled, &e->flags); | |
648 | break; | |
649 | case 2: | |
650 | /* Enable this handler. */ | |
651 | set_bit(Enabled, &e->flags); | |
652 | break; | |
653 | case 3: | |
654 | /* Delete this handler. */ | |
ea7d4c04 | 655 | root = file_inode(file)->i_sb->s_root; |
5955102c | 656 | inode_lock(d_inode(root)); |
1da177e4 | 657 | |
baba1b29 ON |
658 | if (!list_empty(&e->list)) |
659 | kill_node(e); | |
1da177e4 | 660 | |
5955102c | 661 | inode_unlock(d_inode(root)); |
e6084d4a MF |
662 | break; |
663 | default: | |
664 | return res; | |
1da177e4 | 665 | } |
e6084d4a | 666 | |
1da177e4 LT |
667 | return count; |
668 | } | |
669 | ||
4b6f5d20 | 670 | static const struct file_operations bm_entry_operations = { |
1da177e4 LT |
671 | .read = bm_entry_read, |
672 | .write = bm_entry_write, | |
6038f373 | 673 | .llseek = default_llseek, |
1da177e4 LT |
674 | }; |
675 | ||
676 | /* /register */ | |
677 | ||
678 | static ssize_t bm_register_write(struct file *file, const char __user *buffer, | |
679 | size_t count, loff_t *ppos) | |
680 | { | |
681 | Node *e; | |
682 | struct inode *inode; | |
ea7d4c04 AV |
683 | struct super_block *sb = file_inode(file)->i_sb; |
684 | struct dentry *root = sb->s_root, *dentry; | |
1da177e4 LT |
685 | int err = 0; |
686 | ||
687 | e = create_entry(buffer, count); | |
688 | ||
689 | if (IS_ERR(e)) | |
690 | return PTR_ERR(e); | |
691 | ||
5955102c | 692 | inode_lock(d_inode(root)); |
1da177e4 LT |
693 | dentry = lookup_one_len(e->name, root, strlen(e->name)); |
694 | err = PTR_ERR(dentry); | |
695 | if (IS_ERR(dentry)) | |
696 | goto out; | |
697 | ||
698 | err = -EEXIST; | |
75c3cfa8 | 699 | if (d_really_is_positive(dentry)) |
1da177e4 LT |
700 | goto out2; |
701 | ||
702 | inode = bm_get_inode(sb, S_IFREG | 0644); | |
703 | ||
704 | err = -ENOMEM; | |
705 | if (!inode) | |
706 | goto out2; | |
707 | ||
1f5ce9e9 | 708 | err = simple_pin_fs(&bm_fs_type, &bm_mnt, &entry_count); |
1da177e4 LT |
709 | if (err) { |
710 | iput(inode); | |
711 | inode = NULL; | |
712 | goto out2; | |
713 | } | |
714 | ||
948b701a JB |
715 | if (e->flags & MISC_FMT_OPEN_FILE) { |
716 | struct file *f; | |
717 | ||
718 | f = open_exec(e->interpreter); | |
719 | if (IS_ERR(f)) { | |
720 | err = PTR_ERR(f); | |
721 | pr_notice("register: failed to install interpreter file %s\n", e->interpreter); | |
722 | simple_release_fs(&bm_mnt, &entry_count); | |
723 | iput(inode); | |
724 | inode = NULL; | |
725 | goto out2; | |
726 | } | |
727 | e->interp_file = f; | |
728 | } | |
729 | ||
1da177e4 | 730 | e->dentry = dget(dentry); |
8e18e294 | 731 | inode->i_private = e; |
1da177e4 LT |
732 | inode->i_fop = &bm_entry_operations; |
733 | ||
734 | d_instantiate(dentry, inode); | |
735 | write_lock(&entries_lock); | |
736 | list_add(&e->list, &entries); | |
737 | write_unlock(&entries_lock); | |
738 | ||
739 | err = 0; | |
740 | out2: | |
741 | dput(dentry); | |
742 | out: | |
5955102c | 743 | inode_unlock(d_inode(root)); |
1da177e4 LT |
744 | |
745 | if (err) { | |
746 | kfree(e); | |
948b701a | 747 | return err; |
1da177e4 LT |
748 | } |
749 | return count; | |
750 | } | |
751 | ||
4b6f5d20 | 752 | static const struct file_operations bm_register_operations = { |
1da177e4 | 753 | .write = bm_register_write, |
6038f373 | 754 | .llseek = noop_llseek, |
1da177e4 LT |
755 | }; |
756 | ||
757 | /* /status */ | |
758 | ||
759 | static ssize_t | |
760 | bm_status_read(struct file *file, char __user *buf, size_t nbytes, loff_t *ppos) | |
761 | { | |
87113e80 | 762 | char *s = enabled ? "enabled\n" : "disabled\n"; |
1da177e4 | 763 | |
92f4c701 | 764 | return simple_read_from_buffer(buf, nbytes, ppos, s, strlen(s)); |
1da177e4 LT |
765 | } |
766 | ||
e6084d4a | 767 | static ssize_t bm_status_write(struct file *file, const char __user *buffer, |
1da177e4 LT |
768 | size_t count, loff_t *ppos) |
769 | { | |
770 | int res = parse_command(buffer, count); | |
771 | struct dentry *root; | |
772 | ||
773 | switch (res) { | |
e6084d4a MF |
774 | case 1: |
775 | /* Disable all handlers. */ | |
776 | enabled = 0; | |
777 | break; | |
778 | case 2: | |
779 | /* Enable all handlers. */ | |
780 | enabled = 1; | |
781 | break; | |
782 | case 3: | |
783 | /* Delete all handlers. */ | |
ea7d4c04 | 784 | root = file_inode(file)->i_sb->s_root; |
5955102c | 785 | inode_lock(d_inode(root)); |
1da177e4 | 786 | |
e6084d4a | 787 | while (!list_empty(&entries)) |
baba1b29 | 788 | kill_node(list_first_entry(&entries, Node, list)); |
1da177e4 | 789 | |
5955102c | 790 | inode_unlock(d_inode(root)); |
e6084d4a MF |
791 | break; |
792 | default: | |
793 | return res; | |
1da177e4 | 794 | } |
e6084d4a | 795 | |
1da177e4 LT |
796 | return count; |
797 | } | |
798 | ||
4b6f5d20 | 799 | static const struct file_operations bm_status_operations = { |
1da177e4 LT |
800 | .read = bm_status_read, |
801 | .write = bm_status_write, | |
6038f373 | 802 | .llseek = default_llseek, |
1da177e4 LT |
803 | }; |
804 | ||
805 | /* Superblock handling */ | |
806 | ||
ee9b6d61 | 807 | static const struct super_operations s_ops = { |
1da177e4 | 808 | .statfs = simple_statfs, |
b57922d9 | 809 | .evict_inode = bm_evict_inode, |
1da177e4 LT |
810 | }; |
811 | ||
bc99a664 | 812 | static int bm_fill_super(struct super_block *sb, struct fs_context *fc) |
1da177e4 | 813 | { |
e6084d4a | 814 | int err; |
cda37124 | 815 | static const struct tree_descr bm_files[] = { |
1a1c9bb4 JL |
816 | [2] = {"status", &bm_status_operations, S_IWUSR|S_IRUGO}, |
817 | [3] = {"register", &bm_register_operations, S_IWUSR}, | |
1da177e4 LT |
818 | /* last one */ {""} |
819 | }; | |
e6084d4a MF |
820 | |
821 | err = simple_fill_super(sb, BINFMTFS_MAGIC, bm_files); | |
1da177e4 LT |
822 | if (!err) |
823 | sb->s_op = &s_ops; | |
824 | return err; | |
825 | } | |
826 | ||
bc99a664 | 827 | static int bm_get_tree(struct fs_context *fc) |
1da177e4 | 828 | { |
bc99a664 DH |
829 | return get_tree_single(fc, bm_fill_super); |
830 | } | |
831 | ||
832 | static const struct fs_context_operations bm_context_ops = { | |
833 | .get_tree = bm_get_tree, | |
834 | }; | |
835 | ||
836 | static int bm_init_fs_context(struct fs_context *fc) | |
837 | { | |
838 | fc->ops = &bm_context_ops; | |
839 | return 0; | |
1da177e4 LT |
840 | } |
841 | ||
842 | static struct linux_binfmt misc_format = { | |
843 | .module = THIS_MODULE, | |
844 | .load_binary = load_misc_binary, | |
845 | }; | |
846 | ||
847 | static struct file_system_type bm_fs_type = { | |
848 | .owner = THIS_MODULE, | |
849 | .name = "binfmt_misc", | |
bc99a664 | 850 | .init_fs_context = bm_init_fs_context, |
1da177e4 LT |
851 | .kill_sb = kill_litter_super, |
852 | }; | |
7f78e035 | 853 | MODULE_ALIAS_FS("binfmt_misc"); |
1da177e4 LT |
854 | |
855 | static int __init init_misc_binfmt(void) | |
856 | { | |
857 | int err = register_filesystem(&bm_fs_type); | |
8fc3dc5a AV |
858 | if (!err) |
859 | insert_binfmt(&misc_format); | |
1da177e4 LT |
860 | return err; |
861 | } | |
862 | ||
863 | static void __exit exit_misc_binfmt(void) | |
864 | { | |
865 | unregister_binfmt(&misc_format); | |
866 | unregister_filesystem(&bm_fs_type); | |
867 | } | |
868 | ||
869 | core_initcall(init_misc_binfmt); | |
870 | module_exit(exit_misc_binfmt); | |
871 | MODULE_LICENSE("GPL"); |