projects / deliverable / linux.git / blob
? search:
summary | shortlog | log | commit | commitdiff | tree
blame | history | raw | HEAD
bnx2x: Change to driver version 1.72.10-0
[deliverable/linux.git] / net / core / filter.c
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.
16 * Kris Katterjohn - Added many additional checks in sk_chk_filter()
17 */
18
19 #include <linux/module.h>
20 #include <linux/types.h>
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>
28 #include <linux/gfp.h>
29 #include <net/ip.h>
30 #include <net/protocol.h>
31 #include <net/netlink.h>
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>
38 #include <asm/unaligned.h>
39 #include <linux/filter.h>
40 #include <linux/reciprocal_div.h>
41 #include <linux/ratelimit.h>
42
43 /* No hurry in this branch */
44 static void *__load_pointer(const struct sk_buff *skb, int k, unsigned int size)
45 {
46 u8 *ptr = NULL;
47
48 if (k >= SKF_NET_OFF)
49 ptr = skb_network_header(skb) + k - SKF_NET_OFF;
50 else if (k >= SKF_LL_OFF)
51 ptr = skb_mac_header(skb) + k - SKF_LL_OFF;
52
53 if (ptr >= skb->head && ptr + size <= skb_tail_pointer(skb))
54 return ptr;
55 return NULL;
56 }
57
58 static inline void *load_pointer(const struct sk_buff *skb, int k,
59 unsigned int size, void *buffer)
60 {
61 if (k >= 0)
62 return skb_header_pointer(skb, k, size, buffer);
63 return __load_pointer(skb, k, size);
64 }
65
66 /**
67 * sk_filter - run a packet through a socket filter
68 * @sk: sock associated with &sk_buff
69 * @skb: buffer to filter
70 *
71 * Run the filter code and then cut skb->data to correct size returned by
72 * sk_run_filter. If pkt_len is 0 we toss packet. If skb->len is smaller
73 * than pkt_len we keep whole skb->data. This is the socket level
74 * wrapper to sk_run_filter. It returns 0 if the packet should
75 * be accepted or -EPERM if the packet should be tossed.
76 *
77 */
78 int sk_filter(struct sock *sk, struct sk_buff *skb)
79 {
80 int err;
81 struct sk_filter *filter;
82
83 err = security_sock_rcv_skb(sk, skb);
84 if (err)
85 return err;
86
87 rcu_read_lock();
88 filter = rcu_dereference(sk->sk_filter);
89 if (filter) {
90 unsigned int pkt_len = SK_RUN_FILTER(filter, skb);
91
92 err = pkt_len ? pskb_trim(skb, pkt_len) : -EPERM;
93 }
94 rcu_read_unlock();
95
96 return err;
97 }
98 EXPORT_SYMBOL(sk_filter);
99
100 /**
101 * sk_run_filter - run a filter on a socket
102 * @skb: buffer to run the filter on
103 * @fentry: filter to apply
104 *
105 * Decode and apply filter instructions to the skb->data.
106 * Return length to keep, 0 for none. @skb is the data we are
107 * filtering, @filter is the array of filter instructions.
108 * Because all jumps are guaranteed to be before last instruction,
109 * and last instruction guaranteed to be a RET, we dont need to check
110 * flen. (We used to pass to this function the length of filter)
111 */
112 unsigned int sk_run_filter(const struct sk_buff *skb,
113 const struct sock_filter *fentry)
114 {
115 void *ptr;
116 u32 A = 0; /* Accumulator */
117 u32 X = 0; /* Index Register */
118 u32 mem[BPF_MEMWORDS]; /* Scratch Memory Store */
119 u32 tmp;
120 int k;
121
122 /*
123 * Process array of filter instructions.
124 */
125 for (;; fentry++) {
126 #if defined(CONFIG_X86_32)
127 #define K (fentry->k)
128 #else
129 const u32 K = fentry->k;
130 #endif
131
132 switch (fentry->code) {
133 case BPF_S_ALU_ADD_X:
134 A += X;
135 continue;
136 case BPF_S_ALU_ADD_K:
137 A += K;
138 continue;
139 case BPF_S_ALU_SUB_X:
140 A -= X;
141 continue;
142 case BPF_S_ALU_SUB_K:
143 A -= K;
144 continue;
145 case BPF_S_ALU_MUL_X:
146 A *= X;
147 continue;
148 case BPF_S_ALU_MUL_K:
149 A *= K;
150 continue;
151 case BPF_S_ALU_DIV_X:
152 if (X == 0)
153 return 0;
154 A /= X;
155 continue;
156 case BPF_S_ALU_DIV_K:
157 A = reciprocal_divide(A, K);
158 continue;
159 case BPF_S_ALU_AND_X:
160 A &= X;
161 continue;
162 case BPF_S_ALU_AND_K:
163 A &= K;
164 continue;
165 case BPF_S_ALU_OR_X:
166 A |= X;
167 continue;
168 case BPF_S_ALU_OR_K:
169 A |= K;
170 continue;
171 case BPF_S_ALU_LSH_X:
172 A <<= X;
173 continue;
174 case BPF_S_ALU_LSH_K:
175 A <<= K;
176 continue;
177 case BPF_S_ALU_RSH_X:
178 A >>= X;
179 continue;
180 case BPF_S_ALU_RSH_K:
181 A >>= K;
182 continue;
183 case BPF_S_ALU_NEG:
184 A = -A;
185 continue;
186 case BPF_S_JMP_JA:
187 fentry += K;
188 continue;
189 case BPF_S_JMP_JGT_K:
190 fentry += (A > K) ? fentry->jt : fentry->jf;
191 continue;
192 case BPF_S_JMP_JGE_K:
193 fentry += (A >= K) ? fentry->jt : fentry->jf;
194 continue;
195 case BPF_S_JMP_JEQ_K:
196 fentry += (A == K) ? fentry->jt : fentry->jf;
197 continue;
198 case BPF_S_JMP_JSET_K:
199 fentry += (A & K) ? fentry->jt : fentry->jf;
200 continue;
201 case BPF_S_JMP_JGT_X:
202 fentry += (A > X) ? fentry->jt : fentry->jf;
203 continue;
204 case BPF_S_JMP_JGE_X:
205 fentry += (A >= X) ? fentry->jt : fentry->jf;
206 continue;
207 case BPF_S_JMP_JEQ_X:
208 fentry += (A == X) ? fentry->jt : fentry->jf;
209 continue;
210 case BPF_S_JMP_JSET_X:
211 fentry += (A & X) ? fentry->jt : fentry->jf;
212 continue;
213 case BPF_S_LD_W_ABS:
214 k = K;
215 load_w:
216 ptr = load_pointer(skb, k, 4, &tmp);
217 if (ptr != NULL) {
218 A = get_unaligned_be32(ptr);
219 continue;
220 }
221 return 0;
222 case BPF_S_LD_H_ABS:
223 k = K;
224 load_h:
225 ptr = load_pointer(skb, k, 2, &tmp);
226 if (ptr != NULL) {
227 A = get_unaligned_be16(ptr);
228 continue;
229 }
230 return 0;
231 case BPF_S_LD_B_ABS:
232 k = K;
233 load_b:
234 ptr = load_pointer(skb, k, 1, &tmp);
235 if (ptr != NULL) {
236 A = *(u8 *)ptr;
237 continue;
238 }
239 return 0;
240 case BPF_S_LD_W_LEN:
241 A = skb->len;
242 continue;
243 case BPF_S_LDX_W_LEN:
244 X = skb->len;
245 continue;
246 case BPF_S_LD_W_IND:
247 k = X + K;
248 goto load_w;
249 case BPF_S_LD_H_IND:
250 k = X + K;
251 goto load_h;
252 case BPF_S_LD_B_IND:
253 k = X + K;
254 goto load_b;
255 case BPF_S_LDX_B_MSH:
256 ptr = load_pointer(skb, K, 1, &tmp);
257 if (ptr != NULL) {
258 X = (*(u8 *)ptr & 0xf) << 2;
259 continue;
260 }
261 return 0;
262 case BPF_S_LD_IMM:
263 A = K;
264 continue;
265 case BPF_S_LDX_IMM:
266 X = K;
267 continue;
268 case BPF_S_LD_MEM:
269 A = mem[K];
270 continue;
271 case BPF_S_LDX_MEM:
272 X = mem[K];
273 continue;
274 case BPF_S_MISC_TAX:
275 X = A;
276 continue;
277 case BPF_S_MISC_TXA:
278 A = X;
279 continue;
280 case BPF_S_RET_K:
281 return K;
282 case BPF_S_RET_A:
283 return A;
284 case BPF_S_ST:
285 mem[K] = A;
286 continue;
287 case BPF_S_STX:
288 mem[K] = X;
289 continue;
290 case BPF_S_ANC_PROTOCOL:
291 A = ntohs(skb->protocol);
292 continue;
293 case BPF_S_ANC_PKTTYPE:
294 A = skb->pkt_type;
295 continue;
296 case BPF_S_ANC_IFINDEX:
297 if (!skb->dev)
298 return 0;
299 A = skb->dev->ifindex;
300 continue;
301 case BPF_S_ANC_MARK:
302 A = skb->mark;
303 continue;
304 case BPF_S_ANC_QUEUE:
305 A = skb->queue_mapping;
306 continue;
307 case BPF_S_ANC_HATYPE:
308 if (!skb->dev)
309 return 0;
310 A = skb->dev->type;
311 continue;
312 case BPF_S_ANC_RXHASH:
313 A = skb->rxhash;
314 continue;
315 case BPF_S_ANC_CPU:
316 A = raw_smp_processor_id();
317 continue;
318 case BPF_S_ANC_ALU_XOR_X:
319 A ^= X;
320 continue;
321 case BPF_S_ANC_NLATTR: {
322 struct nlattr *nla;
323
324 if (skb_is_nonlinear(skb))
325 return 0;
326 if (A > skb->len - sizeof(struct nlattr))
327 return 0;
328
329 nla = nla_find((struct nlattr *)&skb->data[A],
330 skb->len - A, X);
331 if (nla)
332 A = (void *)nla - (void *)skb->data;
333 else
334 A = 0;
335 continue;
336 }
337 case BPF_S_ANC_NLATTR_NEST: {
338 struct nlattr *nla;
339
340 if (skb_is_nonlinear(skb))
341 return 0;
342 if (A > skb->len - sizeof(struct nlattr))
343 return 0;
344
345 nla = (struct nlattr *)&skb->data[A];
346 if (nla->nla_len > A - skb->len)
347 return 0;
348
349 nla = nla_find_nested(nla, X);
350 if (nla)
351 A = (void *)nla - (void *)skb->data;
352 else
353 A = 0;
354 continue;
355 }
356 default:
357 WARN_RATELIMIT(1, "Unknown code:%u jt:%u tf:%u k:%u\n",
358 fentry->code, fentry->jt,
359 fentry->jf, fentry->k);
360 return 0;
361 }
362 }
363
364 return 0;
365 }
366 EXPORT_SYMBOL(sk_run_filter);
367
368 /*
369 * Security :
370 * A BPF program is able to use 16 cells of memory to store intermediate
371 * values (check u32 mem[BPF_MEMWORDS] in sk_run_filter())
372 * As we dont want to clear mem[] array for each packet going through
373 * sk_run_filter(), we check that filter loaded by user never try to read
374 * a cell if not previously written, and we check all branches to be sure
375 * a malicious user doesn't try to abuse us.
376 */
377 static int check_load_and_stores(struct sock_filter *filter, int flen)
378 {
379 u16 *masks, memvalid = 0; /* one bit per cell, 16 cells */
380 int pc, ret = 0;
381
382 BUILD_BUG_ON(BPF_MEMWORDS > 16);
383 masks = kmalloc(flen * sizeof(*masks), GFP_KERNEL);
384 if (!masks)
385 return -ENOMEM;
386 memset(masks, 0xff, flen * sizeof(*masks));
387
388 for (pc = 0; pc < flen; pc++) {
389 memvalid &= masks[pc];
390
391 switch (filter[pc].code) {
392 case BPF_S_ST:
393 case BPF_S_STX:
394 memvalid |= (1 << filter[pc].k);
395 break;
396 case BPF_S_LD_MEM:
397 case BPF_S_LDX_MEM:
398 if (!(memvalid & (1 << filter[pc].k))) {
399 ret = -EINVAL;
400 goto error;
401 }
402 break;
403 case BPF_S_JMP_JA:
404 /* a jump must set masks on target */
405 masks[pc + 1 + filter[pc].k] &= memvalid;
406 memvalid = ~0;
407 break;
408 case BPF_S_JMP_JEQ_K:
409 case BPF_S_JMP_JEQ_X:
410 case BPF_S_JMP_JGE_K:
411 case BPF_S_JMP_JGE_X:
412 case BPF_S_JMP_JGT_K:
413 case BPF_S_JMP_JGT_X:
414 case BPF_S_JMP_JSET_X:
415 case BPF_S_JMP_JSET_K:
416 /* a jump must set masks on targets */
417 masks[pc + 1 + filter[pc].jt] &= memvalid;
418 masks[pc + 1 + filter[pc].jf] &= memvalid;
419 memvalid = ~0;
420 break;
421 }
422 }
423 error:
424 kfree(masks);
425 return ret;
426 }
427
428 /**
429 * sk_chk_filter - verify socket filter code
430 * @filter: filter to verify
431 * @flen: length of filter
432 *
433 * Check the user's filter code. If we let some ugly
434 * filter code slip through kaboom! The filter must contain
435 * no references or jumps that are out of range, no illegal
436 * instructions, and must end with a RET instruction.
437 *
438 * All jumps are forward as they are not signed.
439 *
440 * Returns 0 if the rule set is legal or -EINVAL if not.
441 */
442 int sk_chk_filter(struct sock_filter *filter, unsigned int flen)
443 {
444 /*
445 * Valid instructions are initialized to non-0.
446 * Invalid instructions are initialized to 0.
447 */
448 static const u8 codes[] = {
449 [BPF_ALU|BPF_ADD|BPF_K] = BPF_S_ALU_ADD_K,
450 [BPF_ALU|BPF_ADD|BPF_X] = BPF_S_ALU_ADD_X,
451 [BPF_ALU|BPF_SUB|BPF_K] = BPF_S_ALU_SUB_K,
452 [BPF_ALU|BPF_SUB|BPF_X] = BPF_S_ALU_SUB_X,
453 [BPF_ALU|BPF_MUL|BPF_K] = BPF_S_ALU_MUL_K,
454 [BPF_ALU|BPF_MUL|BPF_X] = BPF_S_ALU_MUL_X,
455 [BPF_ALU|BPF_DIV|BPF_X] = BPF_S_ALU_DIV_X,
456 [BPF_ALU|BPF_AND|BPF_K] = BPF_S_ALU_AND_K,
457 [BPF_ALU|BPF_AND|BPF_X] = BPF_S_ALU_AND_X,
458 [BPF_ALU|BPF_OR|BPF_K] = BPF_S_ALU_OR_K,
459 [BPF_ALU|BPF_OR|BPF_X] = BPF_S_ALU_OR_X,
460 [BPF_ALU|BPF_LSH|BPF_K] = BPF_S_ALU_LSH_K,
461 [BPF_ALU|BPF_LSH|BPF_X] = BPF_S_ALU_LSH_X,
462 [BPF_ALU|BPF_RSH|BPF_K] = BPF_S_ALU_RSH_K,
463 [BPF_ALU|BPF_RSH|BPF_X] = BPF_S_ALU_RSH_X,
464 [BPF_ALU|BPF_NEG] = BPF_S_ALU_NEG,
465 [BPF_LD|BPF_W|BPF_ABS] = BPF_S_LD_W_ABS,
466 [BPF_LD|BPF_H|BPF_ABS] = BPF_S_LD_H_ABS,
467 [BPF_LD|BPF_B|BPF_ABS] = BPF_S_LD_B_ABS,
468 [BPF_LD|BPF_W|BPF_LEN] = BPF_S_LD_W_LEN,
469 [BPF_LD|BPF_W|BPF_IND] = BPF_S_LD_W_IND,
470 [BPF_LD|BPF_H|BPF_IND] = BPF_S_LD_H_IND,
471 [BPF_LD|BPF_B|BPF_IND] = BPF_S_LD_B_IND,
472 [BPF_LD|BPF_IMM] = BPF_S_LD_IMM,
473 [BPF_LDX|BPF_W|BPF_LEN] = BPF_S_LDX_W_LEN,
474 [BPF_LDX|BPF_B|BPF_MSH] = BPF_S_LDX_B_MSH,
475 [BPF_LDX|BPF_IMM] = BPF_S_LDX_IMM,
476 [BPF_MISC|BPF_TAX] = BPF_S_MISC_TAX,
477 [BPF_MISC|BPF_TXA] = BPF_S_MISC_TXA,
478 [BPF_RET|BPF_K] = BPF_S_RET_K,
479 [BPF_RET|BPF_A] = BPF_S_RET_A,
480 [BPF_ALU|BPF_DIV|BPF_K] = BPF_S_ALU_DIV_K,
481 [BPF_LD|BPF_MEM] = BPF_S_LD_MEM,
482 [BPF_LDX|BPF_MEM] = BPF_S_LDX_MEM,
483 [BPF_ST] = BPF_S_ST,
484 [BPF_STX] = BPF_S_STX,
485 [BPF_JMP|BPF_JA] = BPF_S_JMP_JA,
486 [BPF_JMP|BPF_JEQ|BPF_K] = BPF_S_JMP_JEQ_K,
487 [BPF_JMP|BPF_JEQ|BPF_X] = BPF_S_JMP_JEQ_X,
488 [BPF_JMP|BPF_JGE|BPF_K] = BPF_S_JMP_JGE_K,
489 [BPF_JMP|BPF_JGE|BPF_X] = BPF_S_JMP_JGE_X,
490 [BPF_JMP|BPF_JGT|BPF_K] = BPF_S_JMP_JGT_K,
491 [BPF_JMP|BPF_JGT|BPF_X] = BPF_S_JMP_JGT_X,
492 [BPF_JMP|BPF_JSET|BPF_K] = BPF_S_JMP_JSET_K,
493 [BPF_JMP|BPF_JSET|BPF_X] = BPF_S_JMP_JSET_X,
494 };
495 int pc;
496
497 if (flen == 0 || flen > BPF_MAXINSNS)
498 return -EINVAL;
499
500 /* check the filter code now */
501 for (pc = 0; pc < flen; pc++) {
502 struct sock_filter *ftest = &filter[pc];
503 u16 code = ftest->code;
504
505 if (code >= ARRAY_SIZE(codes))
506 return -EINVAL;
507 code = codes[code];
508 if (!code)
509 return -EINVAL;
510 /* Some instructions need special checks */
511 switch (code) {
512 case BPF_S_ALU_DIV_K:
513 /* check for division by zero */
514 if (ftest->k == 0)
515 return -EINVAL;
516 ftest->k = reciprocal_value(ftest->k);
517 break;
518 case BPF_S_LD_MEM:
519 case BPF_S_LDX_MEM:
520 case BPF_S_ST:
521 case BPF_S_STX:
522 /* check for invalid memory addresses */
523 if (ftest->k >= BPF_MEMWORDS)
524 return -EINVAL;
525 break;
526 case BPF_S_JMP_JA:
527 /*
528 * Note, the large ftest->k might cause loops.
529 * Compare this with conditional jumps below,
530 * where offsets are limited. --ANK (981016)
531 */
532 if (ftest->k >= (unsigned)(flen-pc-1))
533 return -EINVAL;
534 break;
535 case BPF_S_JMP_JEQ_K:
536 case BPF_S_JMP_JEQ_X:
537 case BPF_S_JMP_JGE_K:
538 case BPF_S_JMP_JGE_X:
539 case BPF_S_JMP_JGT_K:
540 case BPF_S_JMP_JGT_X:
541 case BPF_S_JMP_JSET_X:
542 case BPF_S_JMP_JSET_K:
543 /* for conditionals both must be safe */
544 if (pc + ftest->jt + 1 >= flen ||
545 pc + ftest->jf + 1 >= flen)
546 return -EINVAL;
547 break;
548 case BPF_S_LD_W_ABS:
549 case BPF_S_LD_H_ABS:
550 case BPF_S_LD_B_ABS:
551 #define ANCILLARY(CODE) case SKF_AD_OFF + SKF_AD_##CODE: \
552 code = BPF_S_ANC_##CODE; \
553 break
554 switch (ftest->k) {
555 ANCILLARY(PROTOCOL);
556 ANCILLARY(PKTTYPE);
557 ANCILLARY(IFINDEX);
558 ANCILLARY(NLATTR);
559 ANCILLARY(NLATTR_NEST);
560 ANCILLARY(MARK);
561 ANCILLARY(QUEUE);
562 ANCILLARY(HATYPE);
563 ANCILLARY(RXHASH);
564 ANCILLARY(CPU);
565 ANCILLARY(ALU_XOR_X);
566 }
567 }
568 ftest->code = code;
569 }
570
571 /* last instruction must be a RET code */
572 switch (filter[flen - 1].code) {
573 case BPF_S_RET_K:
574 case BPF_S_RET_A:
575 return check_load_and_stores(filter, flen);
576 }
577 return -EINVAL;
578 }
579 EXPORT_SYMBOL(sk_chk_filter);
580
581 /**
582 * sk_filter_release_rcu - Release a socket filter by rcu_head
583 * @rcu: rcu_head that contains the sk_filter to free
584 */
585 void sk_filter_release_rcu(struct rcu_head *rcu)
586 {
587 struct sk_filter *fp = container_of(rcu, struct sk_filter, rcu);
588
589 bpf_jit_free(fp);
590 kfree(fp);
591 }
592 EXPORT_SYMBOL(sk_filter_release_rcu);
593
594 static int __sk_prepare_filter(struct sk_filter *fp)
595 {
596 int err;
597
598 fp->bpf_func = sk_run_filter;
599
600 err = sk_chk_filter(fp->insns, fp->len);
601 if (err)
602 return err;
603
604 bpf_jit_compile(fp);
605 return 0;
606 }
607
608 /**
609 * sk_unattached_filter_create - create an unattached filter
610 * @fprog: the filter program
611 * @sk: the socket to use
612 *
613 * Create a filter independent ofr any socket. We first run some
614 * sanity checks on it to make sure it does not explode on us later.
615 * If an error occurs or there is insufficient memory for the filter
616 * a negative errno code is returned. On success the return is zero.
617 */
618 int sk_unattached_filter_create(struct sk_filter **pfp,
619 struct sock_fprog *fprog)
620 {
621 struct sk_filter *fp;
622 unsigned int fsize = sizeof(struct sock_filter) * fprog->len;
623 int err;
624
625 /* Make sure new filter is there and in the right amounts. */
626 if (fprog->filter == NULL)
627 return -EINVAL;
628
629 fp = kmalloc(fsize + sizeof(*fp), GFP_KERNEL);
630 if (!fp)
631 return -ENOMEM;
632 memcpy(fp->insns, fprog->filter, fsize);
633
634 atomic_set(&fp->refcnt, 1);
635 fp->len = fprog->len;
636
637 err = __sk_prepare_filter(fp);
638 if (err)
639 goto free_mem;
640
641 *pfp = fp;
642 return 0;
643 free_mem:
644 kfree(fp);
645 return err;
646 }
647 EXPORT_SYMBOL_GPL(sk_unattached_filter_create);
648
649 void sk_unattached_filter_destroy(struct sk_filter *fp)
650 {
651 sk_filter_release(fp);
652 }
653 EXPORT_SYMBOL_GPL(sk_unattached_filter_destroy);
654
655 /**
656 * sk_attach_filter - attach a socket filter
657 * @fprog: the filter program
658 * @sk: the socket to use
659 *
660 * Attach the user's filter code. We first run some sanity checks on
661 * it to make sure it does not explode on us later. If an error
662 * occurs or there is insufficient memory for the filter a negative
663 * errno code is returned. On success the return is zero.
664 */
665 int sk_attach_filter(struct sock_fprog *fprog, struct sock *sk)
666 {
667 struct sk_filter *fp, *old_fp;
668 unsigned int fsize = sizeof(struct sock_filter) * fprog->len;
669 int err;
670
671 /* Make sure new filter is there and in the right amounts. */
672 if (fprog->filter == NULL)
673 return -EINVAL;
674
675 fp = sock_kmalloc(sk, fsize+sizeof(*fp), GFP_KERNEL);
676 if (!fp)
677 return -ENOMEM;
678 if (copy_from_user(fp->insns, fprog->filter, fsize)) {
679 sock_kfree_s(sk, fp, fsize+sizeof(*fp));
680 return -EFAULT;
681 }
682
683 atomic_set(&fp->refcnt, 1);
684 fp->len = fprog->len;
685
686 err = __sk_prepare_filter(fp);
687 if (err) {
688 sk_filter_uncharge(sk, fp);
689 return err;
690 }
691
692 old_fp = rcu_dereference_protected(sk->sk_filter,
693 sock_owned_by_user(sk));
694 rcu_assign_pointer(sk->sk_filter, fp);
695
696 if (old_fp)
697 sk_filter_uncharge(sk, old_fp);
698 return 0;
699 }
700 EXPORT_SYMBOL_GPL(sk_attach_filter);
701
702 int sk_detach_filter(struct sock *sk)
703 {
704 int ret = -ENOENT;
705 struct sk_filter *filter;
706
707 filter = rcu_dereference_protected(sk->sk_filter,
708 sock_owned_by_user(sk));
709 if (filter) {
710 RCU_INIT_POINTER(sk->sk_filter, NULL);
711 sk_filter_uncharge(sk, filter);
712 ret = 0;
713 }
714 return ret;
715 }
716 EXPORT_SYMBOL_GPL(sk_detach_filter);
Linux kernel - Deliverables
This page took 0.047513 seconds and 5 git commands to generate.