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Commit | Line | Data |
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1da177e4 LT |
1 | /* |
2 | * Linux Socket Filter - Kernel level socket filtering | |
3 | * | |
4 | * Author: | |
5 | * Jay Schulist <jschlst@samba.org> | |
6 | * | |
7 | * Based on the design of: | |
8 | * - The Berkeley Packet Filter | |
9 | * | |
10 | * This program is free software; you can redistribute it and/or | |
11 | * modify it under the terms of the GNU General Public License | |
12 | * as published by the Free Software Foundation; either version | |
13 | * 2 of the License, or (at your option) any later version. | |
14 | * | |
15 | * Andi Kleen - Fix a few bad bugs and races. | |
93699863 | 16 | * Kris Katterjohn - Added many additional checks in sk_chk_filter() |
1da177e4 LT |
17 | */ |
18 | ||
19 | #include <linux/module.h> | |
20 | #include <linux/types.h> | |
1da177e4 LT |
21 | #include <linux/mm.h> |
22 | #include <linux/fcntl.h> | |
23 | #include <linux/socket.h> | |
24 | #include <linux/in.h> | |
25 | #include <linux/inet.h> | |
26 | #include <linux/netdevice.h> | |
27 | #include <linux/if_packet.h> | |
5a0e3ad6 | 28 | #include <linux/gfp.h> |
1da177e4 LT |
29 | #include <net/ip.h> |
30 | #include <net/protocol.h> | |
4738c1db | 31 | #include <net/netlink.h> |
1da177e4 LT |
32 | #include <linux/skbuff.h> |
33 | #include <net/sock.h> | |
34 | #include <linux/errno.h> | |
35 | #include <linux/timer.h> | |
36 | #include <asm/system.h> | |
37 | #include <asm/uaccess.h> | |
40daafc8 | 38 | #include <asm/unaligned.h> |
1da177e4 LT |
39 | #include <linux/filter.h> |
40 | ||
41 | /* No hurry in this branch */ | |
0b05b2a4 | 42 | static void *__load_pointer(struct sk_buff *skb, int k) |
1da177e4 LT |
43 | { |
44 | u8 *ptr = NULL; | |
45 | ||
46 | if (k >= SKF_NET_OFF) | |
d56f90a7 | 47 | ptr = skb_network_header(skb) + k - SKF_NET_OFF; |
1da177e4 | 48 | else if (k >= SKF_LL_OFF) |
98e399f8 | 49 | ptr = skb_mac_header(skb) + k - SKF_LL_OFF; |
1da177e4 | 50 | |
27a884dc | 51 | if (ptr >= skb->head && ptr < skb_tail_pointer(skb)) |
1da177e4 LT |
52 | return ptr; |
53 | return NULL; | |
54 | } | |
55 | ||
0b05b2a4 | 56 | static inline void *load_pointer(struct sk_buff *skb, int k, |
4ec93edb | 57 | unsigned int size, void *buffer) |
0b05b2a4 PM |
58 | { |
59 | if (k >= 0) | |
60 | return skb_header_pointer(skb, k, size, buffer); | |
61 | else { | |
62 | if (k >= SKF_AD_OFF) | |
63 | return NULL; | |
64 | return __load_pointer(skb, k); | |
65 | } | |
66 | } | |
67 | ||
43db6d65 SH |
68 | /** |
69 | * sk_filter - run a packet through a socket filter | |
70 | * @sk: sock associated with &sk_buff | |
71 | * @skb: buffer to filter | |
43db6d65 SH |
72 | * |
73 | * Run the filter code and then cut skb->data to correct size returned by | |
74 | * sk_run_filter. If pkt_len is 0 we toss packet. If skb->len is smaller | |
75 | * than pkt_len we keep whole skb->data. This is the socket level | |
76 | * wrapper to sk_run_filter. It returns 0 if the packet should | |
77 | * be accepted or -EPERM if the packet should be tossed. | |
78 | * | |
79 | */ | |
80 | int sk_filter(struct sock *sk, struct sk_buff *skb) | |
81 | { | |
82 | int err; | |
83 | struct sk_filter *filter; | |
84 | ||
85 | err = security_sock_rcv_skb(sk, skb); | |
86 | if (err) | |
87 | return err; | |
88 | ||
89 | rcu_read_lock_bh(); | |
a898def2 | 90 | filter = rcu_dereference_bh(sk->sk_filter); |
43db6d65 SH |
91 | if (filter) { |
92 | unsigned int pkt_len = sk_run_filter(skb, filter->insns, | |
93 | filter->len); | |
94 | err = pkt_len ? pskb_trim(skb, pkt_len) : -EPERM; | |
95 | } | |
96 | rcu_read_unlock_bh(); | |
97 | ||
98 | return err; | |
99 | } | |
100 | EXPORT_SYMBOL(sk_filter); | |
101 | ||
1da177e4 | 102 | /** |
2966b66c | 103 | * sk_run_filter - run a filter on a socket |
1da177e4 LT |
104 | * @skb: buffer to run the filter on |
105 | * @filter: filter to apply | |
106 | * @flen: length of filter | |
107 | * | |
108 | * Decode and apply filter instructions to the skb->data. | |
109 | * Return length to keep, 0 for none. skb is the data we are | |
110 | * filtering, filter is the array of filter instructions, and | |
111 | * len is the number of filter blocks in the array. | |
112 | */ | |
4bad4dc9 | 113 | unsigned int sk_run_filter(struct sk_buff *skb, struct sock_filter *filter, int flen) |
1da177e4 | 114 | { |
1da177e4 | 115 | struct sock_filter *fentry; /* We walk down these */ |
0b05b2a4 | 116 | void *ptr; |
2966b66c KK |
117 | u32 A = 0; /* Accumulator */ |
118 | u32 X = 0; /* Index Register */ | |
1da177e4 | 119 | u32 mem[BPF_MEMWORDS]; /* Scratch Memory Store */ |
0b05b2a4 | 120 | u32 tmp; |
1da177e4 LT |
121 | int k; |
122 | int pc; | |
123 | ||
124 | /* | |
125 | * Process array of filter instructions. | |
126 | */ | |
127 | for (pc = 0; pc < flen; pc++) { | |
128 | fentry = &filter[pc]; | |
4ec93edb | 129 | |
1da177e4 LT |
130 | switch (fentry->code) { |
131 | case BPF_ALU|BPF_ADD|BPF_X: | |
132 | A += X; | |
133 | continue; | |
134 | case BPF_ALU|BPF_ADD|BPF_K: | |
135 | A += fentry->k; | |
136 | continue; | |
137 | case BPF_ALU|BPF_SUB|BPF_X: | |
138 | A -= X; | |
139 | continue; | |
140 | case BPF_ALU|BPF_SUB|BPF_K: | |
141 | A -= fentry->k; | |
142 | continue; | |
143 | case BPF_ALU|BPF_MUL|BPF_X: | |
144 | A *= X; | |
145 | continue; | |
146 | case BPF_ALU|BPF_MUL|BPF_K: | |
147 | A *= fentry->k; | |
148 | continue; | |
149 | case BPF_ALU|BPF_DIV|BPF_X: | |
150 | if (X == 0) | |
151 | return 0; | |
152 | A /= X; | |
153 | continue; | |
154 | case BPF_ALU|BPF_DIV|BPF_K: | |
1da177e4 LT |
155 | A /= fentry->k; |
156 | continue; | |
157 | case BPF_ALU|BPF_AND|BPF_X: | |
158 | A &= X; | |
159 | continue; | |
160 | case BPF_ALU|BPF_AND|BPF_K: | |
161 | A &= fentry->k; | |
162 | continue; | |
163 | case BPF_ALU|BPF_OR|BPF_X: | |
164 | A |= X; | |
165 | continue; | |
166 | case BPF_ALU|BPF_OR|BPF_K: | |
167 | A |= fentry->k; | |
168 | continue; | |
169 | case BPF_ALU|BPF_LSH|BPF_X: | |
170 | A <<= X; | |
171 | continue; | |
172 | case BPF_ALU|BPF_LSH|BPF_K: | |
173 | A <<= fentry->k; | |
174 | continue; | |
175 | case BPF_ALU|BPF_RSH|BPF_X: | |
176 | A >>= X; | |
177 | continue; | |
178 | case BPF_ALU|BPF_RSH|BPF_K: | |
179 | A >>= fentry->k; | |
180 | continue; | |
181 | case BPF_ALU|BPF_NEG: | |
182 | A = -A; | |
183 | continue; | |
184 | case BPF_JMP|BPF_JA: | |
185 | pc += fentry->k; | |
186 | continue; | |
187 | case BPF_JMP|BPF_JGT|BPF_K: | |
188 | pc += (A > fentry->k) ? fentry->jt : fentry->jf; | |
189 | continue; | |
190 | case BPF_JMP|BPF_JGE|BPF_K: | |
191 | pc += (A >= fentry->k) ? fentry->jt : fentry->jf; | |
192 | continue; | |
193 | case BPF_JMP|BPF_JEQ|BPF_K: | |
194 | pc += (A == fentry->k) ? fentry->jt : fentry->jf; | |
195 | continue; | |
196 | case BPF_JMP|BPF_JSET|BPF_K: | |
197 | pc += (A & fentry->k) ? fentry->jt : fentry->jf; | |
198 | continue; | |
199 | case BPF_JMP|BPF_JGT|BPF_X: | |
200 | pc += (A > X) ? fentry->jt : fentry->jf; | |
201 | continue; | |
202 | case BPF_JMP|BPF_JGE|BPF_X: | |
203 | pc += (A >= X) ? fentry->jt : fentry->jf; | |
204 | continue; | |
205 | case BPF_JMP|BPF_JEQ|BPF_X: | |
206 | pc += (A == X) ? fentry->jt : fentry->jf; | |
207 | continue; | |
208 | case BPF_JMP|BPF_JSET|BPF_X: | |
209 | pc += (A & X) ? fentry->jt : fentry->jf; | |
210 | continue; | |
211 | case BPF_LD|BPF_W|BPF_ABS: | |
212 | k = fentry->k; | |
e35bedf3 | 213 | load_w: |
0b05b2a4 PM |
214 | ptr = load_pointer(skb, k, 4, &tmp); |
215 | if (ptr != NULL) { | |
d3e2ce3b | 216 | A = get_unaligned_be32(ptr); |
0b05b2a4 | 217 | continue; |
1da177e4 | 218 | } |
1198ad00 | 219 | break; |
1da177e4 LT |
220 | case BPF_LD|BPF_H|BPF_ABS: |
221 | k = fentry->k; | |
e35bedf3 | 222 | load_h: |
0b05b2a4 PM |
223 | ptr = load_pointer(skb, k, 2, &tmp); |
224 | if (ptr != NULL) { | |
d3e2ce3b | 225 | A = get_unaligned_be16(ptr); |
0b05b2a4 | 226 | continue; |
1da177e4 | 227 | } |
1198ad00 | 228 | break; |
1da177e4 LT |
229 | case BPF_LD|BPF_B|BPF_ABS: |
230 | k = fentry->k; | |
231 | load_b: | |
0b05b2a4 PM |
232 | ptr = load_pointer(skb, k, 1, &tmp); |
233 | if (ptr != NULL) { | |
234 | A = *(u8 *)ptr; | |
235 | continue; | |
1da177e4 | 236 | } |
1198ad00 | 237 | break; |
1da177e4 | 238 | case BPF_LD|BPF_W|BPF_LEN: |
3154e540 | 239 | A = skb->len; |
1da177e4 LT |
240 | continue; |
241 | case BPF_LDX|BPF_W|BPF_LEN: | |
3154e540 | 242 | X = skb->len; |
1da177e4 LT |
243 | continue; |
244 | case BPF_LD|BPF_W|BPF_IND: | |
245 | k = X + fentry->k; | |
246 | goto load_w; | |
247 | case BPF_LD|BPF_H|BPF_IND: | |
248 | k = X + fentry->k; | |
249 | goto load_h; | |
250 | case BPF_LD|BPF_B|BPF_IND: | |
251 | k = X + fentry->k; | |
252 | goto load_b; | |
253 | case BPF_LDX|BPF_B|BPF_MSH: | |
0b05b2a4 PM |
254 | ptr = load_pointer(skb, fentry->k, 1, &tmp); |
255 | if (ptr != NULL) { | |
256 | X = (*(u8 *)ptr & 0xf) << 2; | |
257 | continue; | |
258 | } | |
259 | return 0; | |
1da177e4 LT |
260 | case BPF_LD|BPF_IMM: |
261 | A = fentry->k; | |
262 | continue; | |
263 | case BPF_LDX|BPF_IMM: | |
264 | X = fentry->k; | |
265 | continue; | |
266 | case BPF_LD|BPF_MEM: | |
267 | A = mem[fentry->k]; | |
268 | continue; | |
269 | case BPF_LDX|BPF_MEM: | |
270 | X = mem[fentry->k]; | |
271 | continue; | |
272 | case BPF_MISC|BPF_TAX: | |
273 | X = A; | |
274 | continue; | |
275 | case BPF_MISC|BPF_TXA: | |
276 | A = X; | |
277 | continue; | |
278 | case BPF_RET|BPF_K: | |
4bad4dc9 | 279 | return fentry->k; |
1da177e4 | 280 | case BPF_RET|BPF_A: |
4bad4dc9 | 281 | return A; |
1da177e4 LT |
282 | case BPF_ST: |
283 | mem[fentry->k] = A; | |
284 | continue; | |
285 | case BPF_STX: | |
286 | mem[fentry->k] = X; | |
287 | continue; | |
288 | default: | |
93699863 | 289 | WARN_ON(1); |
1da177e4 LT |
290 | return 0; |
291 | } | |
292 | ||
293 | /* | |
294 | * Handle ancillary data, which are impossible | |
295 | * (or very difficult) to get parsing packet contents. | |
296 | */ | |
297 | switch (k-SKF_AD_OFF) { | |
298 | case SKF_AD_PROTOCOL: | |
252e3346 | 299 | A = ntohs(skb->protocol); |
1da177e4 LT |
300 | continue; |
301 | case SKF_AD_PKTTYPE: | |
302 | A = skb->pkt_type; | |
303 | continue; | |
304 | case SKF_AD_IFINDEX: | |
305 | A = skb->dev->ifindex; | |
306 | continue; | |
7e75f93e | 307 | case SKF_AD_MARK: |
308 | A = skb->mark; | |
309 | continue; | |
d19742fb ED |
310 | case SKF_AD_QUEUE: |
311 | A = skb->queue_mapping; | |
312 | continue; | |
4738c1db PM |
313 | case SKF_AD_NLATTR: { |
314 | struct nlattr *nla; | |
315 | ||
316 | if (skb_is_nonlinear(skb)) | |
317 | return 0; | |
318 | if (A > skb->len - sizeof(struct nlattr)) | |
319 | return 0; | |
320 | ||
321 | nla = nla_find((struct nlattr *)&skb->data[A], | |
322 | skb->len - A, X); | |
323 | if (nla) | |
324 | A = (void *)nla - (void *)skb->data; | |
325 | else | |
326 | A = 0; | |
327 | continue; | |
328 | } | |
d214c753 PNA |
329 | case SKF_AD_NLATTR_NEST: { |
330 | struct nlattr *nla; | |
331 | ||
332 | if (skb_is_nonlinear(skb)) | |
333 | return 0; | |
334 | if (A > skb->len - sizeof(struct nlattr)) | |
335 | return 0; | |
336 | ||
337 | nla = (struct nlattr *)&skb->data[A]; | |
338 | if (nla->nla_len > A - skb->len) | |
339 | return 0; | |
340 | ||
341 | nla = nla_find_nested(nla, X); | |
342 | if (nla) | |
343 | A = (void *)nla - (void *)skb->data; | |
344 | else | |
345 | A = 0; | |
346 | continue; | |
347 | } | |
1da177e4 LT |
348 | default: |
349 | return 0; | |
350 | } | |
351 | } | |
352 | ||
353 | return 0; | |
354 | } | |
b715631f | 355 | EXPORT_SYMBOL(sk_run_filter); |
1da177e4 LT |
356 | |
357 | /** | |
358 | * sk_chk_filter - verify socket filter code | |
359 | * @filter: filter to verify | |
360 | * @flen: length of filter | |
361 | * | |
362 | * Check the user's filter code. If we let some ugly | |
363 | * filter code slip through kaboom! The filter must contain | |
93699863 KK |
364 | * no references or jumps that are out of range, no illegal |
365 | * instructions, and must end with a RET instruction. | |
1da177e4 | 366 | * |
7b11f69f KK |
367 | * All jumps are forward as they are not signed. |
368 | * | |
369 | * Returns 0 if the rule set is legal or -EINVAL if not. | |
1da177e4 LT |
370 | */ |
371 | int sk_chk_filter(struct sock_filter *filter, int flen) | |
372 | { | |
373 | struct sock_filter *ftest; | |
374 | int pc; | |
375 | ||
1b93ae64 | 376 | if (flen == 0 || flen > BPF_MAXINSNS) |
1da177e4 LT |
377 | return -EINVAL; |
378 | ||
379 | /* check the filter code now */ | |
380 | for (pc = 0; pc < flen; pc++) { | |
1da177e4 | 381 | ftest = &filter[pc]; |
1da177e4 | 382 | |
93699863 KK |
383 | /* Only allow valid instructions */ |
384 | switch (ftest->code) { | |
385 | case BPF_ALU|BPF_ADD|BPF_K: | |
386 | case BPF_ALU|BPF_ADD|BPF_X: | |
387 | case BPF_ALU|BPF_SUB|BPF_K: | |
388 | case BPF_ALU|BPF_SUB|BPF_X: | |
389 | case BPF_ALU|BPF_MUL|BPF_K: | |
390 | case BPF_ALU|BPF_MUL|BPF_X: | |
391 | case BPF_ALU|BPF_DIV|BPF_X: | |
392 | case BPF_ALU|BPF_AND|BPF_K: | |
393 | case BPF_ALU|BPF_AND|BPF_X: | |
394 | case BPF_ALU|BPF_OR|BPF_K: | |
395 | case BPF_ALU|BPF_OR|BPF_X: | |
396 | case BPF_ALU|BPF_LSH|BPF_K: | |
397 | case BPF_ALU|BPF_LSH|BPF_X: | |
398 | case BPF_ALU|BPF_RSH|BPF_K: | |
399 | case BPF_ALU|BPF_RSH|BPF_X: | |
400 | case BPF_ALU|BPF_NEG: | |
401 | case BPF_LD|BPF_W|BPF_ABS: | |
402 | case BPF_LD|BPF_H|BPF_ABS: | |
403 | case BPF_LD|BPF_B|BPF_ABS: | |
404 | case BPF_LD|BPF_W|BPF_LEN: | |
405 | case BPF_LD|BPF_W|BPF_IND: | |
406 | case BPF_LD|BPF_H|BPF_IND: | |
407 | case BPF_LD|BPF_B|BPF_IND: | |
408 | case BPF_LD|BPF_IMM: | |
409 | case BPF_LDX|BPF_W|BPF_LEN: | |
410 | case BPF_LDX|BPF_B|BPF_MSH: | |
411 | case BPF_LDX|BPF_IMM: | |
412 | case BPF_MISC|BPF_TAX: | |
413 | case BPF_MISC|BPF_TXA: | |
414 | case BPF_RET|BPF_K: | |
415 | case BPF_RET|BPF_A: | |
416 | break; | |
417 | ||
418 | /* Some instructions need special checks */ | |
fb0d366b | 419 | |
93699863 KK |
420 | case BPF_ALU|BPF_DIV|BPF_K: |
421 | /* check for division by zero */ | |
422 | if (ftest->k == 0) | |
1da177e4 | 423 | return -EINVAL; |
93699863 KK |
424 | break; |
425 | ||
426 | case BPF_LD|BPF_MEM: | |
427 | case BPF_LDX|BPF_MEM: | |
428 | case BPF_ST: | |
429 | case BPF_STX: | |
430 | /* check for invalid memory addresses */ | |
431 | if (ftest->k >= BPF_MEMWORDS) | |
432 | return -EINVAL; | |
433 | break; | |
434 | ||
435 | case BPF_JMP|BPF_JA: | |
436 | /* | |
437 | * Note, the large ftest->k might cause loops. | |
438 | * Compare this with conditional jumps below, | |
439 | * where offsets are limited. --ANK (981016) | |
440 | */ | |
441 | if (ftest->k >= (unsigned)(flen-pc-1)) | |
442 | return -EINVAL; | |
443 | break; | |
444 | ||
445 | case BPF_JMP|BPF_JEQ|BPF_K: | |
446 | case BPF_JMP|BPF_JEQ|BPF_X: | |
447 | case BPF_JMP|BPF_JGE|BPF_K: | |
448 | case BPF_JMP|BPF_JGE|BPF_X: | |
449 | case BPF_JMP|BPF_JGT|BPF_K: | |
450 | case BPF_JMP|BPF_JGT|BPF_X: | |
451 | case BPF_JMP|BPF_JSET|BPF_K: | |
452 | case BPF_JMP|BPF_JSET|BPF_X: | |
453 | /* for conditionals both must be safe */ | |
e35bedf3 | 454 | if (pc + ftest->jt + 1 >= flen || |
93699863 KK |
455 | pc + ftest->jf + 1 >= flen) |
456 | return -EINVAL; | |
457 | break; | |
458 | ||
459 | default: | |
460 | return -EINVAL; | |
1da177e4 LT |
461 | } |
462 | } | |
463 | ||
e35bedf3 | 464 | return (BPF_CLASS(filter[flen - 1].code) == BPF_RET) ? 0 : -EINVAL; |
1da177e4 | 465 | } |
b715631f | 466 | EXPORT_SYMBOL(sk_chk_filter); |
1da177e4 | 467 | |
47e958ea PE |
468 | /** |
469 | * sk_filter_rcu_release: Release a socket filter by rcu_head | |
470 | * @rcu: rcu_head that contains the sk_filter to free | |
471 | */ | |
472 | static void sk_filter_rcu_release(struct rcu_head *rcu) | |
473 | { | |
474 | struct sk_filter *fp = container_of(rcu, struct sk_filter, rcu); | |
475 | ||
476 | sk_filter_release(fp); | |
477 | } | |
478 | ||
479 | static void sk_filter_delayed_uncharge(struct sock *sk, struct sk_filter *fp) | |
480 | { | |
481 | unsigned int size = sk_filter_len(fp); | |
482 | ||
483 | atomic_sub(size, &sk->sk_omem_alloc); | |
484 | call_rcu_bh(&fp->rcu, sk_filter_rcu_release); | |
485 | } | |
486 | ||
1da177e4 LT |
487 | /** |
488 | * sk_attach_filter - attach a socket filter | |
489 | * @fprog: the filter program | |
490 | * @sk: the socket to use | |
491 | * | |
492 | * Attach the user's filter code. We first run some sanity checks on | |
493 | * it to make sure it does not explode on us later. If an error | |
494 | * occurs or there is insufficient memory for the filter a negative | |
495 | * errno code is returned. On success the return is zero. | |
496 | */ | |
497 | int sk_attach_filter(struct sock_fprog *fprog, struct sock *sk) | |
498 | { | |
d3904b73 | 499 | struct sk_filter *fp, *old_fp; |
1da177e4 LT |
500 | unsigned int fsize = sizeof(struct sock_filter) * fprog->len; |
501 | int err; | |
502 | ||
503 | /* Make sure new filter is there and in the right amounts. */ | |
e35bedf3 KK |
504 | if (fprog->filter == NULL) |
505 | return -EINVAL; | |
1da177e4 LT |
506 | |
507 | fp = sock_kmalloc(sk, fsize+sizeof(*fp), GFP_KERNEL); | |
508 | if (!fp) | |
509 | return -ENOMEM; | |
510 | if (copy_from_user(fp->insns, fprog->filter, fsize)) { | |
4ec93edb | 511 | sock_kfree_s(sk, fp, fsize+sizeof(*fp)); |
1da177e4 LT |
512 | return -EFAULT; |
513 | } | |
514 | ||
515 | atomic_set(&fp->refcnt, 1); | |
516 | fp->len = fprog->len; | |
517 | ||
518 | err = sk_chk_filter(fp->insns, fp->len); | |
d3904b73 PE |
519 | if (err) { |
520 | sk_filter_uncharge(sk, fp); | |
521 | return err; | |
1da177e4 LT |
522 | } |
523 | ||
d3904b73 | 524 | rcu_read_lock_bh(); |
a898def2 | 525 | old_fp = rcu_dereference_bh(sk->sk_filter); |
d3904b73 PE |
526 | rcu_assign_pointer(sk->sk_filter, fp); |
527 | rcu_read_unlock_bh(); | |
528 | ||
9b013e05 OJ |
529 | if (old_fp) |
530 | sk_filter_delayed_uncharge(sk, old_fp); | |
d3904b73 | 531 | return 0; |
1da177e4 | 532 | } |
5ff3f073 | 533 | EXPORT_SYMBOL_GPL(sk_attach_filter); |
1da177e4 | 534 | |
55b33325 PE |
535 | int sk_detach_filter(struct sock *sk) |
536 | { | |
537 | int ret = -ENOENT; | |
538 | struct sk_filter *filter; | |
539 | ||
540 | rcu_read_lock_bh(); | |
a898def2 | 541 | filter = rcu_dereference_bh(sk->sk_filter); |
55b33325 PE |
542 | if (filter) { |
543 | rcu_assign_pointer(sk->sk_filter, NULL); | |
47e958ea | 544 | sk_filter_delayed_uncharge(sk, filter); |
55b33325 PE |
545 | ret = 0; |
546 | } | |
547 | rcu_read_unlock_bh(); | |
548 | return ret; | |
549 | } | |
5ff3f073 | 550 | EXPORT_SYMBOL_GPL(sk_detach_filter); |