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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> | |
26 | #include <linux/syscalls.h> | |
6e2c10a1 | 27 | #include <linux/fs.h> |
6b899c4e | 28 | #include <linux/uaccess.h> |
1da177e4 | 29 | |
948b701a JB |
30 | #include "internal.h" |
31 | ||
6b899c4e MF |
32 | #ifdef DEBUG |
33 | # define USE_DEBUG 1 | |
34 | #else | |
35 | # define USE_DEBUG 0 | |
36 | #endif | |
1da177e4 LT |
37 | |
38 | enum { | |
39 | VERBOSE_STATUS = 1 /* make it zero to save 400 bytes kernel memory */ | |
40 | }; | |
41 | ||
42 | static LIST_HEAD(entries); | |
43 | static int enabled = 1; | |
44 | ||
45 | enum {Enabled, Magic}; | |
e6084d4a MF |
46 | #define MISC_FMT_PRESERVE_ARGV0 (1 << 31) |
47 | #define MISC_FMT_OPEN_BINARY (1 << 30) | |
48 | #define MISC_FMT_CREDENTIALS (1 << 29) | |
948b701a | 49 | #define MISC_FMT_OPEN_FILE (1 << 28) |
1da177e4 LT |
50 | |
51 | typedef struct { | |
52 | struct list_head list; | |
53 | unsigned long flags; /* type, status, etc. */ | |
54 | int offset; /* offset of magic */ | |
55 | int size; /* size of magic/mask */ | |
56 | char *magic; /* magic or filename extension */ | |
57 | char *mask; /* mask, NULL for exact match */ | |
50097f74 | 58 | const char *interpreter; /* filename of interpreter */ |
1da177e4 LT |
59 | char *name; |
60 | struct dentry *dentry; | |
948b701a | 61 | struct file *interp_file; |
1da177e4 LT |
62 | } Node; |
63 | ||
64 | static DEFINE_RWLOCK(entries_lock); | |
1f5ce9e9 | 65 | static struct file_system_type bm_fs_type; |
1da177e4 LT |
66 | static struct vfsmount *bm_mnt; |
67 | static int entry_count; | |
68 | ||
bbaecc08 MF |
69 | /* |
70 | * Max length of the register string. Determined by: | |
71 | * - 7 delimiters | |
72 | * - name: ~50 bytes | |
73 | * - type: 1 byte | |
74 | * - offset: 3 bytes (has to be smaller than BINPRM_BUF_SIZE) | |
75 | * - magic: 128 bytes (512 in escaped form) | |
76 | * - mask: 128 bytes (512 in escaped form) | |
77 | * - interp: ~50 bytes | |
78 | * - flags: 5 bytes | |
79 | * Round that up a bit, and then back off to hold the internal data | |
80 | * (like struct Node). | |
81 | */ | |
82 | #define MAX_REGISTER_LENGTH 1920 | |
83 | ||
84 | /* | |
1da177e4 LT |
85 | * Check if we support the binfmt |
86 | * if we do, return the node, else NULL | |
87 | * locking is done in load_misc_binary | |
88 | */ | |
89 | static Node *check_file(struct linux_binprm *bprm) | |
90 | { | |
91 | char *p = strrchr(bprm->interp, '.'); | |
92 | struct list_head *l; | |
93 | ||
6b899c4e | 94 | /* Walk all the registered handlers. */ |
1da177e4 LT |
95 | list_for_each(l, &entries) { |
96 | Node *e = list_entry(l, Node, list); | |
97 | char *s; | |
98 | int j; | |
99 | ||
6b899c4e | 100 | /* Make sure this one is currently enabled. */ |
1da177e4 LT |
101 | if (!test_bit(Enabled, &e->flags)) |
102 | continue; | |
103 | ||
6b899c4e | 104 | /* Do matching based on extension if applicable. */ |
1da177e4 LT |
105 | if (!test_bit(Magic, &e->flags)) { |
106 | if (p && !strcmp(e->magic, p + 1)) | |
107 | return e; | |
108 | continue; | |
109 | } | |
110 | ||
6b899c4e | 111 | /* Do matching based on magic & mask. */ |
1da177e4 LT |
112 | s = bprm->buf + e->offset; |
113 | if (e->mask) { | |
114 | for (j = 0; j < e->size; j++) | |
115 | if ((*s++ ^ e->magic[j]) & e->mask[j]) | |
116 | break; | |
117 | } else { | |
118 | for (j = 0; j < e->size; j++) | |
119 | if ((*s++ ^ e->magic[j])) | |
120 | break; | |
121 | } | |
122 | if (j == e->size) | |
123 | return e; | |
124 | } | |
125 | return NULL; | |
126 | } | |
127 | ||
128 | /* | |
129 | * the loader itself | |
130 | */ | |
71613c3b | 131 | static int load_misc_binary(struct linux_binprm *bprm) |
1da177e4 LT |
132 | { |
133 | Node *fmt; | |
e6084d4a | 134 | struct file *interp_file = NULL; |
1da177e4 LT |
135 | int retval; |
136 | int fd_binary = -1; | |
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) { | |
163 | ||
1da177e4 LT |
164 | /* if the binary should be opened on behalf of the |
165 | * interpreter than keep it open and assign descriptor | |
e6084d4a MF |
166 | * to it |
167 | */ | |
c6cb898b | 168 | fd_binary = get_unused_fd_flags(0); |
e6084d4a MF |
169 | if (fd_binary < 0) { |
170 | retval = fd_binary; | |
171 | goto ret; | |
172 | } | |
173 | fd_install(fd_binary, bprm->file); | |
1da177e4 LT |
174 | |
175 | /* if the binary is not readable than enforce mm->dumpable=0 | |
176 | regardless of the interpreter's permissions */ | |
1b5d783c | 177 | would_dump(bprm, bprm->file); |
1da177e4 LT |
178 | |
179 | allow_write_access(bprm->file); | |
180 | bprm->file = NULL; | |
181 | ||
182 | /* mark the bprm that fd should be passed to interp */ | |
183 | bprm->interp_flags |= BINPRM_FLAGS_EXECFD; | |
184 | bprm->interp_data = fd_binary; | |
185 | ||
e6084d4a MF |
186 | } else { |
187 | allow_write_access(bprm->file); | |
188 | fput(bprm->file); | |
189 | bprm->file = NULL; | |
190 | } | |
1da177e4 | 191 | /* make argv[1] be the path to the binary */ |
e6084d4a | 192 | retval = copy_strings_kernel(1, &bprm->interp, bprm); |
1da177e4 | 193 | if (retval < 0) |
e6084d4a | 194 | goto error; |
1da177e4 LT |
195 | bprm->argc++; |
196 | ||
197 | /* add the interp as argv[0] */ | |
50097f74 | 198 | retval = copy_strings_kernel(1, &fmt->interpreter, bprm); |
1da177e4 | 199 | if (retval < 0) |
e6084d4a MF |
200 | goto error; |
201 | bprm->argc++; | |
1da177e4 | 202 | |
b66c5984 | 203 | /* Update interp in case binfmt_script needs it. */ |
50097f74 | 204 | retval = bprm_change_interp(fmt->interpreter, bprm); |
b66c5984 | 205 | if (retval < 0) |
e6084d4a | 206 | goto error; |
1da177e4 | 207 | |
eb23aa03 | 208 | if (fmt->flags & MISC_FMT_OPEN_FILE) { |
19f391eb | 209 | interp_file = file_clone_open(fmt->interp_file); |
948b701a JB |
210 | if (!IS_ERR(interp_file)) |
211 | deny_write_access(interp_file); | |
212 | } else { | |
50097f74 | 213 | interp_file = open_exec(fmt->interpreter); |
948b701a | 214 | } |
e6084d4a MF |
215 | retval = PTR_ERR(interp_file); |
216 | if (IS_ERR(interp_file)) | |
217 | goto error; | |
1da177e4 LT |
218 | |
219 | bprm->file = interp_file; | |
220 | if (fmt->flags & MISC_FMT_CREDENTIALS) { | |
bdd1d2d3 CH |
221 | loff_t pos = 0; |
222 | ||
1da177e4 LT |
223 | /* |
224 | * No need to call prepare_binprm(), it's already been | |
225 | * done. bprm->buf is stale, update from interp_file. | |
226 | */ | |
227 | memset(bprm->buf, 0, BINPRM_BUF_SIZE); | |
bdd1d2d3 CH |
228 | retval = kernel_read(bprm->file, bprm->buf, BINPRM_BUF_SIZE, |
229 | &pos); | |
1da177e4 | 230 | } else |
e6084d4a | 231 | retval = prepare_binprm(bprm); |
1da177e4 LT |
232 | |
233 | if (retval < 0) | |
e6084d4a | 234 | goto error; |
1da177e4 | 235 | |
3c456bfc | 236 | retval = search_binary_handler(bprm); |
1da177e4 | 237 | if (retval < 0) |
e6084d4a | 238 | goto error; |
1da177e4 | 239 | |
e6084d4a | 240 | ret: |
43a4f261 | 241 | dput(fmt->dentry); |
1da177e4 | 242 | return retval; |
e6084d4a | 243 | error: |
1da177e4 | 244 | if (fd_binary > 0) |
2ca2a09d | 245 | ksys_close(fd_binary); |
1da177e4 LT |
246 | bprm->interp_flags = 0; |
247 | bprm->interp_data = 0; | |
e6084d4a | 248 | goto ret; |
1da177e4 LT |
249 | } |
250 | ||
251 | /* Command parsers */ | |
252 | ||
253 | /* | |
254 | * parses and copies one argument enclosed in del from *sp to *dp, | |
255 | * recognising the \x special. | |
256 | * returns pointer to the copied argument or NULL in case of an | |
257 | * error (and sets err) or null argument length. | |
258 | */ | |
259 | static char *scanarg(char *s, char del) | |
260 | { | |
261 | char c; | |
262 | ||
263 | while ((c = *s++) != del) { | |
264 | if (c == '\\' && *s == 'x') { | |
265 | s++; | |
266 | if (!isxdigit(*s++)) | |
267 | return NULL; | |
268 | if (!isxdigit(*s++)) | |
269 | return NULL; | |
270 | } | |
271 | } | |
7d65cf10 | 272 | s[-1] ='\0'; |
1da177e4 LT |
273 | return s; |
274 | } | |
275 | ||
e6084d4a | 276 | static char *check_special_flags(char *sfs, Node *e) |
1da177e4 | 277 | { |
e6084d4a | 278 | char *p = sfs; |
1da177e4 LT |
279 | int cont = 1; |
280 | ||
281 | /* special flags */ | |
282 | while (cont) { | |
283 | switch (*p) { | |
e6084d4a MF |
284 | case 'P': |
285 | pr_debug("register: flag: P (preserve argv0)\n"); | |
286 | p++; | |
287 | e->flags |= MISC_FMT_PRESERVE_ARGV0; | |
288 | break; | |
289 | case 'O': | |
290 | pr_debug("register: flag: O (open binary)\n"); | |
291 | p++; | |
292 | e->flags |= MISC_FMT_OPEN_BINARY; | |
293 | break; | |
294 | case 'C': | |
295 | pr_debug("register: flag: C (preserve creds)\n"); | |
296 | p++; | |
297 | /* this flags also implies the | |
298 | open-binary flag */ | |
299 | e->flags |= (MISC_FMT_CREDENTIALS | | |
300 | MISC_FMT_OPEN_BINARY); | |
301 | break; | |
948b701a JB |
302 | case 'F': |
303 | pr_debug("register: flag: F: open interpreter file now\n"); | |
304 | p++; | |
305 | e->flags |= MISC_FMT_OPEN_FILE; | |
306 | break; | |
e6084d4a MF |
307 | default: |
308 | cont = 0; | |
1da177e4 LT |
309 | } |
310 | } | |
311 | ||
312 | return p; | |
313 | } | |
e6084d4a | 314 | |
1da177e4 LT |
315 | /* |
316 | * This registers a new binary format, it recognises the syntax | |
317 | * ':name:type:offset:magic:mask:interpreter:flags' | |
318 | * where the ':' is the IFS, that can be chosen with the first char | |
319 | */ | |
320 | static Node *create_entry(const char __user *buffer, size_t count) | |
321 | { | |
322 | Node *e; | |
323 | int memsize, err; | |
324 | char *buf, *p; | |
325 | char del; | |
326 | ||
6b899c4e MF |
327 | pr_debug("register: received %zu bytes\n", count); |
328 | ||
1da177e4 LT |
329 | /* some sanity checks */ |
330 | err = -EINVAL; | |
bbaecc08 | 331 | if ((count < 11) || (count > MAX_REGISTER_LENGTH)) |
1da177e4 LT |
332 | goto out; |
333 | ||
334 | err = -ENOMEM; | |
335 | memsize = sizeof(Node) + count + 8; | |
f7e1ad1a | 336 | e = kmalloc(memsize, GFP_KERNEL); |
1da177e4 LT |
337 | if (!e) |
338 | goto out; | |
339 | ||
340 | p = buf = (char *)e + sizeof(Node); | |
341 | ||
342 | memset(e, 0, sizeof(Node)); | |
343 | if (copy_from_user(buf, buffer, count)) | |
e6084d4a | 344 | goto efault; |
1da177e4 LT |
345 | |
346 | del = *p++; /* delimeter */ | |
347 | ||
6b899c4e MF |
348 | pr_debug("register: delim: %#x {%c}\n", del, del); |
349 | ||
350 | /* Pad the buffer with the delim to simplify parsing below. */ | |
e6084d4a | 351 | memset(buf + count, del, 8); |
1da177e4 | 352 | |
6b899c4e | 353 | /* Parse the 'name' field. */ |
1da177e4 LT |
354 | e->name = p; |
355 | p = strchr(p, del); | |
356 | if (!p) | |
e6084d4a | 357 | goto einval; |
1da177e4 LT |
358 | *p++ = '\0'; |
359 | if (!e->name[0] || | |
360 | !strcmp(e->name, ".") || | |
361 | !strcmp(e->name, "..") || | |
362 | strchr(e->name, '/')) | |
e6084d4a | 363 | goto einval; |
6b899c4e MF |
364 | |
365 | pr_debug("register: name: {%s}\n", e->name); | |
366 | ||
367 | /* Parse the 'type' field. */ | |
1da177e4 | 368 | switch (*p++) { |
6b899c4e MF |
369 | case 'E': |
370 | pr_debug("register: type: E (extension)\n"); | |
371 | e->flags = 1 << Enabled; | |
372 | break; | |
373 | case 'M': | |
374 | pr_debug("register: type: M (magic)\n"); | |
375 | e->flags = (1 << Enabled) | (1 << Magic); | |
376 | break; | |
377 | default: | |
e6084d4a | 378 | goto einval; |
1da177e4 LT |
379 | } |
380 | if (*p++ != del) | |
e6084d4a | 381 | goto einval; |
6b899c4e | 382 | |
1da177e4 | 383 | if (test_bit(Magic, &e->flags)) { |
6b899c4e MF |
384 | /* Handle the 'M' (magic) format. */ |
385 | char *s; | |
386 | ||
387 | /* Parse the 'offset' field. */ | |
388 | s = strchr(p, del); | |
1da177e4 | 389 | if (!s) |
e6084d4a | 390 | goto einval; |
5cc41e09 TLSC |
391 | *s = '\0'; |
392 | if (p != s) { | |
393 | int r = kstrtoint(p, 10, &e->offset); | |
394 | if (r != 0 || e->offset < 0) | |
395 | goto einval; | |
396 | } | |
397 | p = s; | |
1da177e4 | 398 | if (*p++) |
e6084d4a | 399 | goto einval; |
6b899c4e MF |
400 | pr_debug("register: offset: %#x\n", e->offset); |
401 | ||
402 | /* Parse the 'magic' field. */ | |
1da177e4 LT |
403 | e->magic = p; |
404 | p = scanarg(p, del); | |
405 | if (!p) | |
e6084d4a | 406 | goto einval; |
7d65cf10 | 407 | if (!e->magic[0]) |
e6084d4a | 408 | goto einval; |
6b899c4e MF |
409 | if (USE_DEBUG) |
410 | print_hex_dump_bytes( | |
411 | KBUILD_MODNAME ": register: magic[raw]: ", | |
412 | DUMP_PREFIX_NONE, e->magic, p - e->magic); | |
413 | ||
414 | /* Parse the 'mask' field. */ | |
1da177e4 LT |
415 | e->mask = p; |
416 | p = scanarg(p, del); | |
417 | if (!p) | |
e6084d4a | 418 | goto einval; |
7d65cf10 | 419 | if (!e->mask[0]) { |
1da177e4 | 420 | e->mask = NULL; |
6b899c4e MF |
421 | pr_debug("register: mask[raw]: none\n"); |
422 | } else if (USE_DEBUG) | |
423 | print_hex_dump_bytes( | |
424 | KBUILD_MODNAME ": register: mask[raw]: ", | |
425 | DUMP_PREFIX_NONE, e->mask, p - e->mask); | |
426 | ||
427 | /* | |
428 | * Decode the magic & mask fields. | |
429 | * Note: while we might have accepted embedded NUL bytes from | |
430 | * above, the unescape helpers here will stop at the first one | |
431 | * it encounters. | |
432 | */ | |
8d82e180 AS |
433 | e->size = string_unescape_inplace(e->magic, UNESCAPE_HEX); |
434 | if (e->mask && | |
435 | string_unescape_inplace(e->mask, UNESCAPE_HEX) != e->size) | |
e6084d4a | 436 | goto einval; |
5cc41e09 TLSC |
437 | if (e->size > BINPRM_BUF_SIZE || |
438 | BINPRM_BUF_SIZE - e->size < e->offset) | |
e6084d4a | 439 | goto einval; |
6b899c4e MF |
440 | pr_debug("register: magic/mask length: %i\n", e->size); |
441 | if (USE_DEBUG) { | |
442 | print_hex_dump_bytes( | |
443 | KBUILD_MODNAME ": register: magic[decoded]: ", | |
444 | DUMP_PREFIX_NONE, e->magic, e->size); | |
445 | ||
446 | if (e->mask) { | |
447 | int i; | |
f7e1ad1a | 448 | char *masked = kmalloc(e->size, GFP_KERNEL); |
6b899c4e MF |
449 | |
450 | print_hex_dump_bytes( | |
451 | KBUILD_MODNAME ": register: mask[decoded]: ", | |
452 | DUMP_PREFIX_NONE, e->mask, e->size); | |
453 | ||
454 | if (masked) { | |
455 | for (i = 0; i < e->size; ++i) | |
456 | masked[i] = e->magic[i] & e->mask[i]; | |
457 | print_hex_dump_bytes( | |
458 | KBUILD_MODNAME ": register: magic[masked]: ", | |
459 | DUMP_PREFIX_NONE, masked, e->size); | |
460 | ||
461 | kfree(masked); | |
462 | } | |
463 | } | |
464 | } | |
1da177e4 | 465 | } else { |
6b899c4e MF |
466 | /* Handle the 'E' (extension) format. */ |
467 | ||
468 | /* Skip the 'offset' field. */ | |
1da177e4 LT |
469 | p = strchr(p, del); |
470 | if (!p) | |
e6084d4a | 471 | goto einval; |
1da177e4 | 472 | *p++ = '\0'; |
6b899c4e MF |
473 | |
474 | /* Parse the 'magic' field. */ | |
1da177e4 LT |
475 | e->magic = p; |
476 | p = strchr(p, del); | |
477 | if (!p) | |
e6084d4a | 478 | goto einval; |
1da177e4 LT |
479 | *p++ = '\0'; |
480 | if (!e->magic[0] || strchr(e->magic, '/')) | |
e6084d4a | 481 | goto einval; |
6b899c4e MF |
482 | pr_debug("register: extension: {%s}\n", e->magic); |
483 | ||
484 | /* Skip the 'mask' field. */ | |
1da177e4 LT |
485 | p = strchr(p, del); |
486 | if (!p) | |
e6084d4a | 487 | goto einval; |
1da177e4 LT |
488 | *p++ = '\0'; |
489 | } | |
6b899c4e MF |
490 | |
491 | /* Parse the 'interpreter' field. */ | |
1da177e4 LT |
492 | e->interpreter = p; |
493 | p = strchr(p, del); | |
494 | if (!p) | |
e6084d4a | 495 | goto einval; |
1da177e4 LT |
496 | *p++ = '\0'; |
497 | if (!e->interpreter[0]) | |
e6084d4a | 498 | goto einval; |
6b899c4e | 499 | pr_debug("register: interpreter: {%s}\n", e->interpreter); |
1da177e4 | 500 | |
6b899c4e | 501 | /* Parse the 'flags' field. */ |
e6084d4a | 502 | p = check_special_flags(p, e); |
1da177e4 LT |
503 | if (*p == '\n') |
504 | p++; | |
505 | if (p != buf + count) | |
e6084d4a MF |
506 | goto einval; |
507 | ||
1da177e4 LT |
508 | return e; |
509 | ||
510 | out: | |
511 | return ERR_PTR(err); | |
512 | ||
e6084d4a | 513 | efault: |
1da177e4 LT |
514 | kfree(e); |
515 | return ERR_PTR(-EFAULT); | |
e6084d4a | 516 | einval: |
1da177e4 LT |
517 | kfree(e); |
518 | return ERR_PTR(-EINVAL); | |
519 | } | |
520 | ||
521 | /* | |
522 | * Set status of entry/binfmt_misc: | |
523 | * '1' enables, '0' disables and '-1' clears entry/binfmt_misc | |
524 | */ | |
525 | static int parse_command(const char __user *buffer, size_t count) | |
526 | { | |
527 | char s[4]; | |
528 | ||
1da177e4 LT |
529 | if (count > 3) |
530 | return -EINVAL; | |
531 | if (copy_from_user(s, buffer, count)) | |
532 | return -EFAULT; | |
de8288b1 AB |
533 | if (!count) |
534 | return 0; | |
e6084d4a | 535 | if (s[count - 1] == '\n') |
1da177e4 LT |
536 | count--; |
537 | if (count == 1 && s[0] == '0') | |
538 | return 1; | |
539 | if (count == 1 && s[0] == '1') | |
540 | return 2; | |
541 | if (count == 2 && s[0] == '-' && s[1] == '1') | |
542 | return 3; | |
543 | return -EINVAL; | |
544 | } | |
545 | ||
546 | /* generic stuff */ | |
547 | ||
548 | static void entry_status(Node *e, char *page) | |
549 | { | |
6ceafb88 RV |
550 | char *dp = page; |
551 | const char *status = "disabled"; | |
1da177e4 LT |
552 | |
553 | if (test_bit(Enabled, &e->flags)) | |
554 | status = "enabled"; | |
555 | ||
556 | if (!VERBOSE_STATUS) { | |
557 | sprintf(page, "%s\n", status); | |
558 | return; | |
559 | } | |
560 | ||
6ceafb88 | 561 | dp += sprintf(dp, "%s\ninterpreter %s\n", status, e->interpreter); |
1da177e4 LT |
562 | |
563 | /* print the special flags */ | |
6ceafb88 | 564 | dp += sprintf(dp, "flags: "); |
e6084d4a MF |
565 | if (e->flags & MISC_FMT_PRESERVE_ARGV0) |
566 | *dp++ = 'P'; | |
567 | if (e->flags & MISC_FMT_OPEN_BINARY) | |
568 | *dp++ = 'O'; | |
569 | if (e->flags & MISC_FMT_CREDENTIALS) | |
570 | *dp++ = 'C'; | |
948b701a JB |
571 | if (e->flags & MISC_FMT_OPEN_FILE) |
572 | *dp++ = 'F'; | |
e6084d4a | 573 | *dp++ = '\n'; |
1da177e4 LT |
574 | |
575 | if (!test_bit(Magic, &e->flags)) { | |
576 | sprintf(dp, "extension .%s\n", e->magic); | |
577 | } else { | |
6ceafb88 RV |
578 | dp += sprintf(dp, "offset %i\nmagic ", e->offset); |
579 | dp = bin2hex(dp, e->magic, e->size); | |
1da177e4 | 580 | if (e->mask) { |
6ceafb88 RV |
581 | dp += sprintf(dp, "\nmask "); |
582 | dp = bin2hex(dp, e->mask, e->size); | |
1da177e4 LT |
583 | } |
584 | *dp++ = '\n'; | |
585 | *dp = '\0'; | |
586 | } | |
587 | } | |
588 | ||
589 | static struct inode *bm_get_inode(struct super_block *sb, int mode) | |
590 | { | |
e6084d4a | 591 | struct inode *inode = new_inode(sb); |
1da177e4 LT |
592 | |
593 | if (inode) { | |
85fe4025 | 594 | inode->i_ino = get_next_ino(); |
1da177e4 | 595 | inode->i_mode = mode; |
1da177e4 | 596 | inode->i_atime = inode->i_mtime = inode->i_ctime = |
c2050a45 | 597 | current_time(inode); |
1da177e4 LT |
598 | } |
599 | return inode; | |
600 | } | |
601 | ||
b57922d9 | 602 | static void bm_evict_inode(struct inode *inode) |
1da177e4 | 603 | { |
83f91827 ON |
604 | Node *e = inode->i_private; |
605 | ||
7e866006 | 606 | if (e && e->flags & MISC_FMT_OPEN_FILE) |
83f91827 ON |
607 | filp_close(e->interp_file, NULL); |
608 | ||
dbd5768f | 609 | clear_inode(inode); |
83f91827 | 610 | kfree(e); |
1da177e4 LT |
611 | } |
612 | ||
613 | static void kill_node(Node *e) | |
614 | { | |
615 | struct dentry *dentry; | |
616 | ||
617 | write_lock(&entries_lock); | |
baba1b29 | 618 | list_del_init(&e->list); |
1da177e4 LT |
619 | write_unlock(&entries_lock); |
620 | ||
baba1b29 ON |
621 | dentry = e->dentry; |
622 | drop_nlink(d_inode(dentry)); | |
623 | d_drop(dentry); | |
624 | dput(dentry); | |
625 | simple_release_fs(&bm_mnt, &entry_count); | |
1da177e4 LT |
626 | } |
627 | ||
628 | /* /<entry> */ | |
629 | ||
630 | static ssize_t | |
e6084d4a | 631 | bm_entry_read(struct file *file, char __user *buf, size_t nbytes, loff_t *ppos) |
1da177e4 | 632 | { |
496ad9aa | 633 | Node *e = file_inode(file)->i_private; |
1da177e4 LT |
634 | ssize_t res; |
635 | char *page; | |
1da177e4 | 636 | |
e6084d4a MF |
637 | page = (char *) __get_free_page(GFP_KERNEL); |
638 | if (!page) | |
1da177e4 LT |
639 | return -ENOMEM; |
640 | ||
641 | entry_status(e, page); | |
1da177e4 | 642 | |
6e2c10a1 AM |
643 | res = simple_read_from_buffer(buf, nbytes, ppos, page, strlen(page)); |
644 | ||
1da177e4 LT |
645 | free_page((unsigned long) page); |
646 | return res; | |
647 | } | |
648 | ||
649 | static ssize_t bm_entry_write(struct file *file, const char __user *buffer, | |
650 | size_t count, loff_t *ppos) | |
651 | { | |
652 | struct dentry *root; | |
496ad9aa | 653 | Node *e = file_inode(file)->i_private; |
1da177e4 LT |
654 | int res = parse_command(buffer, count); |
655 | ||
656 | switch (res) { | |
e6084d4a MF |
657 | case 1: |
658 | /* Disable this handler. */ | |
659 | clear_bit(Enabled, &e->flags); | |
660 | break; | |
661 | case 2: | |
662 | /* Enable this handler. */ | |
663 | set_bit(Enabled, &e->flags); | |
664 | break; | |
665 | case 3: | |
666 | /* Delete this handler. */ | |
ea7d4c04 | 667 | root = file_inode(file)->i_sb->s_root; |
5955102c | 668 | inode_lock(d_inode(root)); |
1da177e4 | 669 | |
baba1b29 ON |
670 | if (!list_empty(&e->list)) |
671 | kill_node(e); | |
1da177e4 | 672 | |
5955102c | 673 | inode_unlock(d_inode(root)); |
e6084d4a MF |
674 | break; |
675 | default: | |
676 | return res; | |
1da177e4 | 677 | } |
e6084d4a | 678 | |
1da177e4 LT |
679 | return count; |
680 | } | |
681 | ||
4b6f5d20 | 682 | static const struct file_operations bm_entry_operations = { |
1da177e4 LT |
683 | .read = bm_entry_read, |
684 | .write = bm_entry_write, | |
6038f373 | 685 | .llseek = default_llseek, |
1da177e4 LT |
686 | }; |
687 | ||
688 | /* /register */ | |
689 | ||
690 | static ssize_t bm_register_write(struct file *file, const char __user *buffer, | |
691 | size_t count, loff_t *ppos) | |
692 | { | |
693 | Node *e; | |
694 | struct inode *inode; | |
ea7d4c04 AV |
695 | struct super_block *sb = file_inode(file)->i_sb; |
696 | struct dentry *root = sb->s_root, *dentry; | |
1da177e4 LT |
697 | int err = 0; |
698 | ||
699 | e = create_entry(buffer, count); | |
700 | ||
701 | if (IS_ERR(e)) | |
702 | return PTR_ERR(e); | |
703 | ||
5955102c | 704 | inode_lock(d_inode(root)); |
1da177e4 LT |
705 | dentry = lookup_one_len(e->name, root, strlen(e->name)); |
706 | err = PTR_ERR(dentry); | |
707 | if (IS_ERR(dentry)) | |
708 | goto out; | |
709 | ||
710 | err = -EEXIST; | |
75c3cfa8 | 711 | if (d_really_is_positive(dentry)) |
1da177e4 LT |
712 | goto out2; |
713 | ||
714 | inode = bm_get_inode(sb, S_IFREG | 0644); | |
715 | ||
716 | err = -ENOMEM; | |
717 | if (!inode) | |
718 | goto out2; | |
719 | ||
1f5ce9e9 | 720 | err = simple_pin_fs(&bm_fs_type, &bm_mnt, &entry_count); |
1da177e4 LT |
721 | if (err) { |
722 | iput(inode); | |
723 | inode = NULL; | |
724 | goto out2; | |
725 | } | |
726 | ||
948b701a JB |
727 | if (e->flags & MISC_FMT_OPEN_FILE) { |
728 | struct file *f; | |
729 | ||
730 | f = open_exec(e->interpreter); | |
731 | if (IS_ERR(f)) { | |
732 | err = PTR_ERR(f); | |
733 | pr_notice("register: failed to install interpreter file %s\n", e->interpreter); | |
734 | simple_release_fs(&bm_mnt, &entry_count); | |
735 | iput(inode); | |
736 | inode = NULL; | |
737 | goto out2; | |
738 | } | |
739 | e->interp_file = f; | |
740 | } | |
741 | ||
1da177e4 | 742 | e->dentry = dget(dentry); |
8e18e294 | 743 | inode->i_private = e; |
1da177e4 LT |
744 | inode->i_fop = &bm_entry_operations; |
745 | ||
746 | d_instantiate(dentry, inode); | |
747 | write_lock(&entries_lock); | |
748 | list_add(&e->list, &entries); | |
749 | write_unlock(&entries_lock); | |
750 | ||
751 | err = 0; | |
752 | out2: | |
753 | dput(dentry); | |
754 | out: | |
5955102c | 755 | inode_unlock(d_inode(root)); |
1da177e4 LT |
756 | |
757 | if (err) { | |
758 | kfree(e); | |
948b701a | 759 | return err; |
1da177e4 LT |
760 | } |
761 | return count; | |
762 | } | |
763 | ||
4b6f5d20 | 764 | static const struct file_operations bm_register_operations = { |
1da177e4 | 765 | .write = bm_register_write, |
6038f373 | 766 | .llseek = noop_llseek, |
1da177e4 LT |
767 | }; |
768 | ||
769 | /* /status */ | |
770 | ||
771 | static ssize_t | |
772 | bm_status_read(struct file *file, char __user *buf, size_t nbytes, loff_t *ppos) | |
773 | { | |
87113e80 | 774 | char *s = enabled ? "enabled\n" : "disabled\n"; |
1da177e4 | 775 | |
92f4c701 | 776 | return simple_read_from_buffer(buf, nbytes, ppos, s, strlen(s)); |
1da177e4 LT |
777 | } |
778 | ||
e6084d4a | 779 | static ssize_t bm_status_write(struct file *file, const char __user *buffer, |
1da177e4 LT |
780 | size_t count, loff_t *ppos) |
781 | { | |
782 | int res = parse_command(buffer, count); | |
783 | struct dentry *root; | |
784 | ||
785 | switch (res) { | |
e6084d4a MF |
786 | case 1: |
787 | /* Disable all handlers. */ | |
788 | enabled = 0; | |
789 | break; | |
790 | case 2: | |
791 | /* Enable all handlers. */ | |
792 | enabled = 1; | |
793 | break; | |
794 | case 3: | |
795 | /* Delete all handlers. */ | |
ea7d4c04 | 796 | root = file_inode(file)->i_sb->s_root; |
5955102c | 797 | inode_lock(d_inode(root)); |
1da177e4 | 798 | |
e6084d4a | 799 | while (!list_empty(&entries)) |
baba1b29 | 800 | kill_node(list_first_entry(&entries, Node, list)); |
1da177e4 | 801 | |
5955102c | 802 | inode_unlock(d_inode(root)); |
e6084d4a MF |
803 | break; |
804 | default: | |
805 | return res; | |
1da177e4 | 806 | } |
e6084d4a | 807 | |
1da177e4 LT |
808 | return count; |
809 | } | |
810 | ||
4b6f5d20 | 811 | static const struct file_operations bm_status_operations = { |
1da177e4 LT |
812 | .read = bm_status_read, |
813 | .write = bm_status_write, | |
6038f373 | 814 | .llseek = default_llseek, |
1da177e4 LT |
815 | }; |
816 | ||
817 | /* Superblock handling */ | |
818 | ||
ee9b6d61 | 819 | static const struct super_operations s_ops = { |
1da177e4 | 820 | .statfs = simple_statfs, |
b57922d9 | 821 | .evict_inode = bm_evict_inode, |
1da177e4 LT |
822 | }; |
823 | ||
e6084d4a | 824 | static int bm_fill_super(struct super_block *sb, void *data, int silent) |
1da177e4 | 825 | { |
e6084d4a | 826 | int err; |
cda37124 | 827 | static const struct tree_descr bm_files[] = { |
1a1c9bb4 JL |
828 | [2] = {"status", &bm_status_operations, S_IWUSR|S_IRUGO}, |
829 | [3] = {"register", &bm_register_operations, S_IWUSR}, | |
1da177e4 LT |
830 | /* last one */ {""} |
831 | }; | |
e6084d4a MF |
832 | |
833 | err = simple_fill_super(sb, BINFMTFS_MAGIC, bm_files); | |
1da177e4 LT |
834 | if (!err) |
835 | sb->s_op = &s_ops; | |
836 | return err; | |
837 | } | |
838 | ||
fc14f2fe AV |
839 | static struct dentry *bm_mount(struct file_system_type *fs_type, |
840 | int flags, const char *dev_name, void *data) | |
1da177e4 | 841 | { |
fc14f2fe | 842 | return mount_single(fs_type, flags, data, bm_fill_super); |
1da177e4 LT |
843 | } |
844 | ||
845 | static struct linux_binfmt misc_format = { | |
846 | .module = THIS_MODULE, | |
847 | .load_binary = load_misc_binary, | |
848 | }; | |
849 | ||
850 | static struct file_system_type bm_fs_type = { | |
851 | .owner = THIS_MODULE, | |
852 | .name = "binfmt_misc", | |
fc14f2fe | 853 | .mount = bm_mount, |
1da177e4 LT |
854 | .kill_sb = kill_litter_super, |
855 | }; | |
7f78e035 | 856 | MODULE_ALIAS_FS("binfmt_misc"); |
1da177e4 LT |
857 | |
858 | static int __init init_misc_binfmt(void) | |
859 | { | |
860 | int err = register_filesystem(&bm_fs_type); | |
8fc3dc5a AV |
861 | if (!err) |
862 | insert_binfmt(&misc_format); | |
1da177e4 LT |
863 | return err; |
864 | } | |
865 | ||
866 | static void __exit exit_misc_binfmt(void) | |
867 | { | |
868 | unregister_binfmt(&misc_format); | |
869 | unregister_filesystem(&bm_fs_type); | |
870 | } | |
871 | ||
872 | core_initcall(init_misc_binfmt); | |
873 | module_exit(exit_misc_binfmt); | |
874 | MODULE_LICENSE("GPL"); |