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 | |
a16b3357 | 224 | retval = prepare_binprm(bprm); |
1da177e4 | 225 | if (retval < 0) |
e6084d4a | 226 | goto error; |
1da177e4 | 227 | |
3c456bfc | 228 | retval = search_binary_handler(bprm); |
1da177e4 | 229 | if (retval < 0) |
e6084d4a | 230 | goto error; |
1da177e4 | 231 | |
e6084d4a | 232 | ret: |
43a4f261 | 233 | dput(fmt->dentry); |
1da177e4 | 234 | return retval; |
e6084d4a | 235 | error: |
1da177e4 | 236 | if (fd_binary > 0) |
2ca2a09d | 237 | ksys_close(fd_binary); |
1da177e4 LT |
238 | bprm->interp_flags = 0; |
239 | bprm->interp_data = 0; | |
e6084d4a | 240 | goto ret; |
1da177e4 LT |
241 | } |
242 | ||
243 | /* Command parsers */ | |
244 | ||
245 | /* | |
246 | * parses and copies one argument enclosed in del from *sp to *dp, | |
247 | * recognising the \x special. | |
248 | * returns pointer to the copied argument or NULL in case of an | |
249 | * error (and sets err) or null argument length. | |
250 | */ | |
251 | static char *scanarg(char *s, char del) | |
252 | { | |
253 | char c; | |
254 | ||
255 | while ((c = *s++) != del) { | |
256 | if (c == '\\' && *s == 'x') { | |
257 | s++; | |
258 | if (!isxdigit(*s++)) | |
259 | return NULL; | |
260 | if (!isxdigit(*s++)) | |
261 | return NULL; | |
262 | } | |
263 | } | |
7d65cf10 | 264 | s[-1] ='\0'; |
1da177e4 LT |
265 | return s; |
266 | } | |
267 | ||
e6084d4a | 268 | static char *check_special_flags(char *sfs, Node *e) |
1da177e4 | 269 | { |
e6084d4a | 270 | char *p = sfs; |
1da177e4 LT |
271 | int cont = 1; |
272 | ||
273 | /* special flags */ | |
274 | while (cont) { | |
275 | switch (*p) { | |
e6084d4a MF |
276 | case 'P': |
277 | pr_debug("register: flag: P (preserve argv0)\n"); | |
278 | p++; | |
279 | e->flags |= MISC_FMT_PRESERVE_ARGV0; | |
280 | break; | |
281 | case 'O': | |
282 | pr_debug("register: flag: O (open binary)\n"); | |
283 | p++; | |
284 | e->flags |= MISC_FMT_OPEN_BINARY; | |
285 | break; | |
286 | case 'C': | |
287 | pr_debug("register: flag: C (preserve creds)\n"); | |
288 | p++; | |
289 | /* this flags also implies the | |
290 | open-binary flag */ | |
291 | e->flags |= (MISC_FMT_CREDENTIALS | | |
292 | MISC_FMT_OPEN_BINARY); | |
293 | break; | |
948b701a JB |
294 | case 'F': |
295 | pr_debug("register: flag: F: open interpreter file now\n"); | |
296 | p++; | |
297 | e->flags |= MISC_FMT_OPEN_FILE; | |
298 | break; | |
e6084d4a MF |
299 | default: |
300 | cont = 0; | |
1da177e4 LT |
301 | } |
302 | } | |
303 | ||
304 | return p; | |
305 | } | |
e6084d4a | 306 | |
1da177e4 LT |
307 | /* |
308 | * This registers a new binary format, it recognises the syntax | |
309 | * ':name:type:offset:magic:mask:interpreter:flags' | |
310 | * where the ':' is the IFS, that can be chosen with the first char | |
311 | */ | |
312 | static Node *create_entry(const char __user *buffer, size_t count) | |
313 | { | |
314 | Node *e; | |
315 | int memsize, err; | |
316 | char *buf, *p; | |
317 | char del; | |
318 | ||
6b899c4e MF |
319 | pr_debug("register: received %zu bytes\n", count); |
320 | ||
1da177e4 LT |
321 | /* some sanity checks */ |
322 | err = -EINVAL; | |
bbaecc08 | 323 | if ((count < 11) || (count > MAX_REGISTER_LENGTH)) |
1da177e4 LT |
324 | goto out; |
325 | ||
326 | err = -ENOMEM; | |
327 | memsize = sizeof(Node) + count + 8; | |
f7e1ad1a | 328 | e = kmalloc(memsize, GFP_KERNEL); |
1da177e4 LT |
329 | if (!e) |
330 | goto out; | |
331 | ||
332 | p = buf = (char *)e + sizeof(Node); | |
333 | ||
334 | memset(e, 0, sizeof(Node)); | |
335 | if (copy_from_user(buf, buffer, count)) | |
e6084d4a | 336 | goto efault; |
1da177e4 LT |
337 | |
338 | del = *p++; /* delimeter */ | |
339 | ||
6b899c4e MF |
340 | pr_debug("register: delim: %#x {%c}\n", del, del); |
341 | ||
342 | /* Pad the buffer with the delim to simplify parsing below. */ | |
e6084d4a | 343 | memset(buf + count, del, 8); |
1da177e4 | 344 | |
6b899c4e | 345 | /* Parse the 'name' field. */ |
1da177e4 LT |
346 | e->name = p; |
347 | p = strchr(p, del); | |
348 | if (!p) | |
e6084d4a | 349 | goto einval; |
1da177e4 LT |
350 | *p++ = '\0'; |
351 | if (!e->name[0] || | |
352 | !strcmp(e->name, ".") || | |
353 | !strcmp(e->name, "..") || | |
354 | strchr(e->name, '/')) | |
e6084d4a | 355 | goto einval; |
6b899c4e MF |
356 | |
357 | pr_debug("register: name: {%s}\n", e->name); | |
358 | ||
359 | /* Parse the 'type' field. */ | |
1da177e4 | 360 | switch (*p++) { |
6b899c4e MF |
361 | case 'E': |
362 | pr_debug("register: type: E (extension)\n"); | |
363 | e->flags = 1 << Enabled; | |
364 | break; | |
365 | case 'M': | |
366 | pr_debug("register: type: M (magic)\n"); | |
367 | e->flags = (1 << Enabled) | (1 << Magic); | |
368 | break; | |
369 | default: | |
e6084d4a | 370 | goto einval; |
1da177e4 LT |
371 | } |
372 | if (*p++ != del) | |
e6084d4a | 373 | goto einval; |
6b899c4e | 374 | |
1da177e4 | 375 | if (test_bit(Magic, &e->flags)) { |
6b899c4e MF |
376 | /* Handle the 'M' (magic) format. */ |
377 | char *s; | |
378 | ||
379 | /* Parse the 'offset' field. */ | |
380 | s = strchr(p, del); | |
1da177e4 | 381 | if (!s) |
e6084d4a | 382 | goto einval; |
5cc41e09 TLSC |
383 | *s = '\0'; |
384 | if (p != s) { | |
385 | int r = kstrtoint(p, 10, &e->offset); | |
386 | if (r != 0 || e->offset < 0) | |
387 | goto einval; | |
388 | } | |
389 | p = s; | |
1da177e4 | 390 | if (*p++) |
e6084d4a | 391 | goto einval; |
6b899c4e MF |
392 | pr_debug("register: offset: %#x\n", e->offset); |
393 | ||
394 | /* Parse the 'magic' field. */ | |
1da177e4 LT |
395 | e->magic = p; |
396 | p = scanarg(p, del); | |
397 | if (!p) | |
e6084d4a | 398 | goto einval; |
7d65cf10 | 399 | if (!e->magic[0]) |
e6084d4a | 400 | goto einval; |
6b899c4e MF |
401 | if (USE_DEBUG) |
402 | print_hex_dump_bytes( | |
403 | KBUILD_MODNAME ": register: magic[raw]: ", | |
404 | DUMP_PREFIX_NONE, e->magic, p - e->magic); | |
405 | ||
406 | /* Parse the 'mask' field. */ | |
1da177e4 LT |
407 | e->mask = p; |
408 | p = scanarg(p, del); | |
409 | if (!p) | |
e6084d4a | 410 | goto einval; |
7d65cf10 | 411 | if (!e->mask[0]) { |
1da177e4 | 412 | e->mask = NULL; |
6b899c4e MF |
413 | pr_debug("register: mask[raw]: none\n"); |
414 | } else if (USE_DEBUG) | |
415 | print_hex_dump_bytes( | |
416 | KBUILD_MODNAME ": register: mask[raw]: ", | |
417 | DUMP_PREFIX_NONE, e->mask, p - e->mask); | |
418 | ||
419 | /* | |
420 | * Decode the magic & mask fields. | |
421 | * Note: while we might have accepted embedded NUL bytes from | |
422 | * above, the unescape helpers here will stop at the first one | |
423 | * it encounters. | |
424 | */ | |
8d82e180 AS |
425 | e->size = string_unescape_inplace(e->magic, UNESCAPE_HEX); |
426 | if (e->mask && | |
427 | string_unescape_inplace(e->mask, UNESCAPE_HEX) != e->size) | |
e6084d4a | 428 | goto einval; |
5cc41e09 TLSC |
429 | if (e->size > BINPRM_BUF_SIZE || |
430 | BINPRM_BUF_SIZE - e->size < e->offset) | |
e6084d4a | 431 | goto einval; |
6b899c4e MF |
432 | pr_debug("register: magic/mask length: %i\n", e->size); |
433 | if (USE_DEBUG) { | |
434 | print_hex_dump_bytes( | |
435 | KBUILD_MODNAME ": register: magic[decoded]: ", | |
436 | DUMP_PREFIX_NONE, e->magic, e->size); | |
437 | ||
438 | if (e->mask) { | |
439 | int i; | |
f7e1ad1a | 440 | char *masked = kmalloc(e->size, GFP_KERNEL); |
6b899c4e MF |
441 | |
442 | print_hex_dump_bytes( | |
443 | KBUILD_MODNAME ": register: mask[decoded]: ", | |
444 | DUMP_PREFIX_NONE, e->mask, e->size); | |
445 | ||
446 | if (masked) { | |
447 | for (i = 0; i < e->size; ++i) | |
448 | masked[i] = e->magic[i] & e->mask[i]; | |
449 | print_hex_dump_bytes( | |
450 | KBUILD_MODNAME ": register: magic[masked]: ", | |
451 | DUMP_PREFIX_NONE, masked, e->size); | |
452 | ||
453 | kfree(masked); | |
454 | } | |
455 | } | |
456 | } | |
1da177e4 | 457 | } else { |
6b899c4e MF |
458 | /* Handle the 'E' (extension) format. */ |
459 | ||
460 | /* Skip the 'offset' field. */ | |
1da177e4 LT |
461 | p = strchr(p, del); |
462 | if (!p) | |
e6084d4a | 463 | goto einval; |
1da177e4 | 464 | *p++ = '\0'; |
6b899c4e MF |
465 | |
466 | /* Parse the 'magic' field. */ | |
1da177e4 LT |
467 | e->magic = p; |
468 | p = strchr(p, del); | |
469 | if (!p) | |
e6084d4a | 470 | goto einval; |
1da177e4 LT |
471 | *p++ = '\0'; |
472 | if (!e->magic[0] || strchr(e->magic, '/')) | |
e6084d4a | 473 | goto einval; |
6b899c4e MF |
474 | pr_debug("register: extension: {%s}\n", e->magic); |
475 | ||
476 | /* Skip the 'mask' field. */ | |
1da177e4 LT |
477 | p = strchr(p, del); |
478 | if (!p) | |
e6084d4a | 479 | goto einval; |
1da177e4 LT |
480 | *p++ = '\0'; |
481 | } | |
6b899c4e MF |
482 | |
483 | /* Parse the 'interpreter' field. */ | |
1da177e4 LT |
484 | e->interpreter = p; |
485 | p = strchr(p, del); | |
486 | if (!p) | |
e6084d4a | 487 | goto einval; |
1da177e4 LT |
488 | *p++ = '\0'; |
489 | if (!e->interpreter[0]) | |
e6084d4a | 490 | goto einval; |
6b899c4e | 491 | pr_debug("register: interpreter: {%s}\n", e->interpreter); |
1da177e4 | 492 | |
6b899c4e | 493 | /* Parse the 'flags' field. */ |
e6084d4a | 494 | p = check_special_flags(p, e); |
1da177e4 LT |
495 | if (*p == '\n') |
496 | p++; | |
497 | if (p != buf + count) | |
e6084d4a MF |
498 | goto einval; |
499 | ||
1da177e4 LT |
500 | return e; |
501 | ||
502 | out: | |
503 | return ERR_PTR(err); | |
504 | ||
e6084d4a | 505 | efault: |
1da177e4 LT |
506 | kfree(e); |
507 | return ERR_PTR(-EFAULT); | |
e6084d4a | 508 | einval: |
1da177e4 LT |
509 | kfree(e); |
510 | return ERR_PTR(-EINVAL); | |
511 | } | |
512 | ||
513 | /* | |
514 | * Set status of entry/binfmt_misc: | |
515 | * '1' enables, '0' disables and '-1' clears entry/binfmt_misc | |
516 | */ | |
517 | static int parse_command(const char __user *buffer, size_t count) | |
518 | { | |
519 | char s[4]; | |
520 | ||
1da177e4 LT |
521 | if (count > 3) |
522 | return -EINVAL; | |
523 | if (copy_from_user(s, buffer, count)) | |
524 | return -EFAULT; | |
de8288b1 AB |
525 | if (!count) |
526 | return 0; | |
e6084d4a | 527 | if (s[count - 1] == '\n') |
1da177e4 LT |
528 | count--; |
529 | if (count == 1 && s[0] == '0') | |
530 | return 1; | |
531 | if (count == 1 && s[0] == '1') | |
532 | return 2; | |
533 | if (count == 2 && s[0] == '-' && s[1] == '1') | |
534 | return 3; | |
535 | return -EINVAL; | |
536 | } | |
537 | ||
538 | /* generic stuff */ | |
539 | ||
540 | static void entry_status(Node *e, char *page) | |
541 | { | |
6ceafb88 RV |
542 | char *dp = page; |
543 | const char *status = "disabled"; | |
1da177e4 LT |
544 | |
545 | if (test_bit(Enabled, &e->flags)) | |
546 | status = "enabled"; | |
547 | ||
548 | if (!VERBOSE_STATUS) { | |
549 | sprintf(page, "%s\n", status); | |
550 | return; | |
551 | } | |
552 | ||
6ceafb88 | 553 | dp += sprintf(dp, "%s\ninterpreter %s\n", status, e->interpreter); |
1da177e4 LT |
554 | |
555 | /* print the special flags */ | |
6ceafb88 | 556 | dp += sprintf(dp, "flags: "); |
e6084d4a MF |
557 | if (e->flags & MISC_FMT_PRESERVE_ARGV0) |
558 | *dp++ = 'P'; | |
559 | if (e->flags & MISC_FMT_OPEN_BINARY) | |
560 | *dp++ = 'O'; | |
561 | if (e->flags & MISC_FMT_CREDENTIALS) | |
562 | *dp++ = 'C'; | |
948b701a JB |
563 | if (e->flags & MISC_FMT_OPEN_FILE) |
564 | *dp++ = 'F'; | |
e6084d4a | 565 | *dp++ = '\n'; |
1da177e4 LT |
566 | |
567 | if (!test_bit(Magic, &e->flags)) { | |
568 | sprintf(dp, "extension .%s\n", e->magic); | |
569 | } else { | |
6ceafb88 RV |
570 | dp += sprintf(dp, "offset %i\nmagic ", e->offset); |
571 | dp = bin2hex(dp, e->magic, e->size); | |
1da177e4 | 572 | if (e->mask) { |
6ceafb88 RV |
573 | dp += sprintf(dp, "\nmask "); |
574 | dp = bin2hex(dp, e->mask, e->size); | |
1da177e4 LT |
575 | } |
576 | *dp++ = '\n'; | |
577 | *dp = '\0'; | |
578 | } | |
579 | } | |
580 | ||
581 | static struct inode *bm_get_inode(struct super_block *sb, int mode) | |
582 | { | |
e6084d4a | 583 | struct inode *inode = new_inode(sb); |
1da177e4 LT |
584 | |
585 | if (inode) { | |
85fe4025 | 586 | inode->i_ino = get_next_ino(); |
1da177e4 | 587 | inode->i_mode = mode; |
1da177e4 | 588 | inode->i_atime = inode->i_mtime = inode->i_ctime = |
c2050a45 | 589 | current_time(inode); |
1da177e4 LT |
590 | } |
591 | return inode; | |
592 | } | |
593 | ||
b57922d9 | 594 | static void bm_evict_inode(struct inode *inode) |
1da177e4 | 595 | { |
83f91827 ON |
596 | Node *e = inode->i_private; |
597 | ||
7e866006 | 598 | if (e && e->flags & MISC_FMT_OPEN_FILE) |
83f91827 ON |
599 | filp_close(e->interp_file, NULL); |
600 | ||
dbd5768f | 601 | clear_inode(inode); |
83f91827 | 602 | kfree(e); |
1da177e4 LT |
603 | } |
604 | ||
605 | static void kill_node(Node *e) | |
606 | { | |
607 | struct dentry *dentry; | |
608 | ||
609 | write_lock(&entries_lock); | |
baba1b29 | 610 | list_del_init(&e->list); |
1da177e4 LT |
611 | write_unlock(&entries_lock); |
612 | ||
baba1b29 ON |
613 | dentry = e->dentry; |
614 | drop_nlink(d_inode(dentry)); | |
615 | d_drop(dentry); | |
616 | dput(dentry); | |
617 | simple_release_fs(&bm_mnt, &entry_count); | |
1da177e4 LT |
618 | } |
619 | ||
620 | /* /<entry> */ | |
621 | ||
622 | static ssize_t | |
e6084d4a | 623 | bm_entry_read(struct file *file, char __user *buf, size_t nbytes, loff_t *ppos) |
1da177e4 | 624 | { |
496ad9aa | 625 | Node *e = file_inode(file)->i_private; |
1da177e4 LT |
626 | ssize_t res; |
627 | char *page; | |
1da177e4 | 628 | |
e6084d4a MF |
629 | page = (char *) __get_free_page(GFP_KERNEL); |
630 | if (!page) | |
1da177e4 LT |
631 | return -ENOMEM; |
632 | ||
633 | entry_status(e, page); | |
1da177e4 | 634 | |
6e2c10a1 AM |
635 | res = simple_read_from_buffer(buf, nbytes, ppos, page, strlen(page)); |
636 | ||
1da177e4 LT |
637 | free_page((unsigned long) page); |
638 | return res; | |
639 | } | |
640 | ||
641 | static ssize_t bm_entry_write(struct file *file, const char __user *buffer, | |
642 | size_t count, loff_t *ppos) | |
643 | { | |
644 | struct dentry *root; | |
496ad9aa | 645 | Node *e = file_inode(file)->i_private; |
1da177e4 LT |
646 | int res = parse_command(buffer, count); |
647 | ||
648 | switch (res) { | |
e6084d4a MF |
649 | case 1: |
650 | /* Disable this handler. */ | |
651 | clear_bit(Enabled, &e->flags); | |
652 | break; | |
653 | case 2: | |
654 | /* Enable this handler. */ | |
655 | set_bit(Enabled, &e->flags); | |
656 | break; | |
657 | case 3: | |
658 | /* Delete this handler. */ | |
ea7d4c04 | 659 | root = file_inode(file)->i_sb->s_root; |
5955102c | 660 | inode_lock(d_inode(root)); |
1da177e4 | 661 | |
baba1b29 ON |
662 | if (!list_empty(&e->list)) |
663 | kill_node(e); | |
1da177e4 | 664 | |
5955102c | 665 | inode_unlock(d_inode(root)); |
e6084d4a MF |
666 | break; |
667 | default: | |
668 | return res; | |
1da177e4 | 669 | } |
e6084d4a | 670 | |
1da177e4 LT |
671 | return count; |
672 | } | |
673 | ||
4b6f5d20 | 674 | static const struct file_operations bm_entry_operations = { |
1da177e4 LT |
675 | .read = bm_entry_read, |
676 | .write = bm_entry_write, | |
6038f373 | 677 | .llseek = default_llseek, |
1da177e4 LT |
678 | }; |
679 | ||
680 | /* /register */ | |
681 | ||
682 | static ssize_t bm_register_write(struct file *file, const char __user *buffer, | |
683 | size_t count, loff_t *ppos) | |
684 | { | |
685 | Node *e; | |
686 | struct inode *inode; | |
ea7d4c04 AV |
687 | struct super_block *sb = file_inode(file)->i_sb; |
688 | struct dentry *root = sb->s_root, *dentry; | |
1da177e4 LT |
689 | int err = 0; |
690 | ||
691 | e = create_entry(buffer, count); | |
692 | ||
693 | if (IS_ERR(e)) | |
694 | return PTR_ERR(e); | |
695 | ||
5955102c | 696 | inode_lock(d_inode(root)); |
1da177e4 LT |
697 | dentry = lookup_one_len(e->name, root, strlen(e->name)); |
698 | err = PTR_ERR(dentry); | |
699 | if (IS_ERR(dentry)) | |
700 | goto out; | |
701 | ||
702 | err = -EEXIST; | |
75c3cfa8 | 703 | if (d_really_is_positive(dentry)) |
1da177e4 LT |
704 | goto out2; |
705 | ||
706 | inode = bm_get_inode(sb, S_IFREG | 0644); | |
707 | ||
708 | err = -ENOMEM; | |
709 | if (!inode) | |
710 | goto out2; | |
711 | ||
1f5ce9e9 | 712 | err = simple_pin_fs(&bm_fs_type, &bm_mnt, &entry_count); |
1da177e4 LT |
713 | if (err) { |
714 | iput(inode); | |
715 | inode = NULL; | |
716 | goto out2; | |
717 | } | |
718 | ||
948b701a JB |
719 | if (e->flags & MISC_FMT_OPEN_FILE) { |
720 | struct file *f; | |
721 | ||
722 | f = open_exec(e->interpreter); | |
723 | if (IS_ERR(f)) { | |
724 | err = PTR_ERR(f); | |
725 | pr_notice("register: failed to install interpreter file %s\n", e->interpreter); | |
726 | simple_release_fs(&bm_mnt, &entry_count); | |
727 | iput(inode); | |
728 | inode = NULL; | |
729 | goto out2; | |
730 | } | |
731 | e->interp_file = f; | |
732 | } | |
733 | ||
1da177e4 | 734 | e->dentry = dget(dentry); |
8e18e294 | 735 | inode->i_private = e; |
1da177e4 LT |
736 | inode->i_fop = &bm_entry_operations; |
737 | ||
738 | d_instantiate(dentry, inode); | |
739 | write_lock(&entries_lock); | |
740 | list_add(&e->list, &entries); | |
741 | write_unlock(&entries_lock); | |
742 | ||
743 | err = 0; | |
744 | out2: | |
745 | dput(dentry); | |
746 | out: | |
5955102c | 747 | inode_unlock(d_inode(root)); |
1da177e4 LT |
748 | |
749 | if (err) { | |
750 | kfree(e); | |
948b701a | 751 | return err; |
1da177e4 LT |
752 | } |
753 | return count; | |
754 | } | |
755 | ||
4b6f5d20 | 756 | static const struct file_operations bm_register_operations = { |
1da177e4 | 757 | .write = bm_register_write, |
6038f373 | 758 | .llseek = noop_llseek, |
1da177e4 LT |
759 | }; |
760 | ||
761 | /* /status */ | |
762 | ||
763 | static ssize_t | |
764 | bm_status_read(struct file *file, char __user *buf, size_t nbytes, loff_t *ppos) | |
765 | { | |
87113e80 | 766 | char *s = enabled ? "enabled\n" : "disabled\n"; |
1da177e4 | 767 | |
92f4c701 | 768 | return simple_read_from_buffer(buf, nbytes, ppos, s, strlen(s)); |
1da177e4 LT |
769 | } |
770 | ||
e6084d4a | 771 | static ssize_t bm_status_write(struct file *file, const char __user *buffer, |
1da177e4 LT |
772 | size_t count, loff_t *ppos) |
773 | { | |
774 | int res = parse_command(buffer, count); | |
775 | struct dentry *root; | |
776 | ||
777 | switch (res) { | |
e6084d4a MF |
778 | case 1: |
779 | /* Disable all handlers. */ | |
780 | enabled = 0; | |
781 | break; | |
782 | case 2: | |
783 | /* Enable all handlers. */ | |
784 | enabled = 1; | |
785 | break; | |
786 | case 3: | |
787 | /* Delete all handlers. */ | |
ea7d4c04 | 788 | root = file_inode(file)->i_sb->s_root; |
5955102c | 789 | inode_lock(d_inode(root)); |
1da177e4 | 790 | |
e6084d4a | 791 | while (!list_empty(&entries)) |
baba1b29 | 792 | kill_node(list_first_entry(&entries, Node, list)); |
1da177e4 | 793 | |
5955102c | 794 | inode_unlock(d_inode(root)); |
e6084d4a MF |
795 | break; |
796 | default: | |
797 | return res; | |
1da177e4 | 798 | } |
e6084d4a | 799 | |
1da177e4 LT |
800 | return count; |
801 | } | |
802 | ||
4b6f5d20 | 803 | static const struct file_operations bm_status_operations = { |
1da177e4 LT |
804 | .read = bm_status_read, |
805 | .write = bm_status_write, | |
6038f373 | 806 | .llseek = default_llseek, |
1da177e4 LT |
807 | }; |
808 | ||
809 | /* Superblock handling */ | |
810 | ||
ee9b6d61 | 811 | static const struct super_operations s_ops = { |
1da177e4 | 812 | .statfs = simple_statfs, |
b57922d9 | 813 | .evict_inode = bm_evict_inode, |
1da177e4 LT |
814 | }; |
815 | ||
bc99a664 | 816 | static int bm_fill_super(struct super_block *sb, struct fs_context *fc) |
1da177e4 | 817 | { |
e6084d4a | 818 | int err; |
cda37124 | 819 | static const struct tree_descr bm_files[] = { |
1a1c9bb4 JL |
820 | [2] = {"status", &bm_status_operations, S_IWUSR|S_IRUGO}, |
821 | [3] = {"register", &bm_register_operations, S_IWUSR}, | |
1da177e4 LT |
822 | /* last one */ {""} |
823 | }; | |
e6084d4a MF |
824 | |
825 | err = simple_fill_super(sb, BINFMTFS_MAGIC, bm_files); | |
1da177e4 LT |
826 | if (!err) |
827 | sb->s_op = &s_ops; | |
828 | return err; | |
829 | } | |
830 | ||
bc99a664 | 831 | static int bm_get_tree(struct fs_context *fc) |
1da177e4 | 832 | { |
bc99a664 DH |
833 | return get_tree_single(fc, bm_fill_super); |
834 | } | |
835 | ||
836 | static const struct fs_context_operations bm_context_ops = { | |
837 | .get_tree = bm_get_tree, | |
838 | }; | |
839 | ||
840 | static int bm_init_fs_context(struct fs_context *fc) | |
841 | { | |
842 | fc->ops = &bm_context_ops; | |
843 | return 0; | |
1da177e4 LT |
844 | } |
845 | ||
846 | static struct linux_binfmt misc_format = { | |
847 | .module = THIS_MODULE, | |
848 | .load_binary = load_misc_binary, | |
849 | }; | |
850 | ||
851 | static struct file_system_type bm_fs_type = { | |
852 | .owner = THIS_MODULE, | |
853 | .name = "binfmt_misc", | |
bc99a664 | 854 | .init_fs_context = bm_init_fs_context, |
1da177e4 LT |
855 | .kill_sb = kill_litter_super, |
856 | }; | |
7f78e035 | 857 | MODULE_ALIAS_FS("binfmt_misc"); |
1da177e4 LT |
858 | |
859 | static int __init init_misc_binfmt(void) | |
860 | { | |
861 | int err = register_filesystem(&bm_fs_type); | |
8fc3dc5a AV |
862 | if (!err) |
863 | insert_binfmt(&misc_format); | |
1da177e4 LT |
864 | return err; |
865 | } | |
866 | ||
867 | static void __exit exit_misc_binfmt(void) | |
868 | { | |
869 | unregister_binfmt(&misc_format); | |
870 | unregister_filesystem(&bm_fs_type); | |
871 | } | |
872 | ||
873 | core_initcall(init_misc_binfmt); | |
874 | module_exit(exit_misc_binfmt); | |
875 | MODULE_LICENSE("GPL"); |