Commit | Line | Data |
---|---|---|
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> | |
1da177e4 | 36 | #include <asm/uaccess.h> |
40daafc8 | 37 | #include <asm/unaligned.h> |
1da177e4 | 38 | #include <linux/filter.h> |
c26aed40 | 39 | #include <linux/reciprocal_div.h> |
86e4ca66 | 40 | #include <linux/ratelimit.h> |
46b325c7 | 41 | #include <linux/seccomp.h> |
1da177e4 | 42 | |
f03fb3f4 JS |
43 | /* No hurry in this branch |
44 | * | |
45 | * Exported for the bpf jit load helper. | |
46 | */ | |
47 | void *bpf_internal_load_pointer_neg_helper(const struct sk_buff *skb, int k, unsigned int size) | |
1da177e4 LT |
48 | { |
49 | u8 *ptr = NULL; | |
50 | ||
51 | if (k >= SKF_NET_OFF) | |
d56f90a7 | 52 | ptr = skb_network_header(skb) + k - SKF_NET_OFF; |
1da177e4 | 53 | else if (k >= SKF_LL_OFF) |
98e399f8 | 54 | ptr = skb_mac_header(skb) + k - SKF_LL_OFF; |
1da177e4 | 55 | |
4bc65dd8 | 56 | if (ptr >= skb->head && ptr + size <= skb_tail_pointer(skb)) |
1da177e4 LT |
57 | return ptr; |
58 | return NULL; | |
59 | } | |
60 | ||
62ab0812 | 61 | static inline void *load_pointer(const struct sk_buff *skb, int k, |
4ec93edb | 62 | unsigned int size, void *buffer) |
0b05b2a4 PM |
63 | { |
64 | if (k >= 0) | |
65 | return skb_header_pointer(skb, k, size, buffer); | |
f03fb3f4 | 66 | return bpf_internal_load_pointer_neg_helper(skb, k, size); |
0b05b2a4 PM |
67 | } |
68 | ||
43db6d65 SH |
69 | /** |
70 | * sk_filter - run a packet through a socket filter | |
71 | * @sk: sock associated with &sk_buff | |
72 | * @skb: buffer to filter | |
43db6d65 SH |
73 | * |
74 | * Run the filter code and then cut skb->data to correct size returned by | |
75 | * sk_run_filter. If pkt_len is 0 we toss packet. If skb->len is smaller | |
76 | * than pkt_len we keep whole skb->data. This is the socket level | |
77 | * wrapper to sk_run_filter. It returns 0 if the packet should | |
78 | * be accepted or -EPERM if the packet should be tossed. | |
79 | * | |
80 | */ | |
81 | int sk_filter(struct sock *sk, struct sk_buff *skb) | |
82 | { | |
83 | int err; | |
84 | struct sk_filter *filter; | |
85 | ||
86 | err = security_sock_rcv_skb(sk, skb); | |
87 | if (err) | |
88 | return err; | |
89 | ||
80f8f102 ED |
90 | rcu_read_lock(); |
91 | filter = rcu_dereference(sk->sk_filter); | |
43db6d65 | 92 | if (filter) { |
0a14842f | 93 | unsigned int pkt_len = SK_RUN_FILTER(filter, skb); |
0d7da9dd | 94 | |
43db6d65 SH |
95 | err = pkt_len ? pskb_trim(skb, pkt_len) : -EPERM; |
96 | } | |
80f8f102 | 97 | rcu_read_unlock(); |
43db6d65 SH |
98 | |
99 | return err; | |
100 | } | |
101 | EXPORT_SYMBOL(sk_filter); | |
102 | ||
1da177e4 | 103 | /** |
2966b66c | 104 | * sk_run_filter - run a filter on a socket |
1da177e4 | 105 | * @skb: buffer to run the filter on |
697d0e33 | 106 | * @fentry: filter to apply |
1da177e4 LT |
107 | * |
108 | * Decode and apply filter instructions to the skb->data. | |
93aaae2e ED |
109 | * Return length to keep, 0 for none. @skb is the data we are |
110 | * filtering, @filter is the array of filter instructions. | |
111 | * Because all jumps are guaranteed to be before last instruction, | |
112 | * and last instruction guaranteed to be a RET, we dont need to check | |
113 | * flen. (We used to pass to this function the length of filter) | |
1da177e4 | 114 | */ |
62ab0812 ED |
115 | unsigned int sk_run_filter(const struct sk_buff *skb, |
116 | const struct sock_filter *fentry) | |
1da177e4 | 117 | { |
0b05b2a4 | 118 | void *ptr; |
2966b66c KK |
119 | u32 A = 0; /* Accumulator */ |
120 | u32 X = 0; /* Index Register */ | |
1da177e4 | 121 | u32 mem[BPF_MEMWORDS]; /* Scratch Memory Store */ |
0b05b2a4 | 122 | u32 tmp; |
1da177e4 | 123 | int k; |
1da177e4 LT |
124 | |
125 | /* | |
126 | * Process array of filter instructions. | |
127 | */ | |
93aaae2e ED |
128 | for (;; fentry++) { |
129 | #if defined(CONFIG_X86_32) | |
130 | #define K (fentry->k) | |
131 | #else | |
132 | const u32 K = fentry->k; | |
133 | #endif | |
4ec93edb | 134 | |
1da177e4 | 135 | switch (fentry->code) { |
01f2f3f6 | 136 | case BPF_S_ALU_ADD_X: |
1da177e4 LT |
137 | A += X; |
138 | continue; | |
01f2f3f6 | 139 | case BPF_S_ALU_ADD_K: |
93aaae2e | 140 | A += K; |
1da177e4 | 141 | continue; |
01f2f3f6 | 142 | case BPF_S_ALU_SUB_X: |
1da177e4 LT |
143 | A -= X; |
144 | continue; | |
01f2f3f6 | 145 | case BPF_S_ALU_SUB_K: |
93aaae2e | 146 | A -= K; |
1da177e4 | 147 | continue; |
01f2f3f6 | 148 | case BPF_S_ALU_MUL_X: |
1da177e4 LT |
149 | A *= X; |
150 | continue; | |
01f2f3f6 | 151 | case BPF_S_ALU_MUL_K: |
93aaae2e | 152 | A *= K; |
1da177e4 | 153 | continue; |
01f2f3f6 | 154 | case BPF_S_ALU_DIV_X: |
1da177e4 LT |
155 | if (X == 0) |
156 | return 0; | |
157 | A /= X; | |
158 | continue; | |
01f2f3f6 | 159 | case BPF_S_ALU_DIV_K: |
c26aed40 | 160 | A = reciprocal_divide(A, K); |
1da177e4 | 161 | continue; |
01f2f3f6 | 162 | case BPF_S_ALU_AND_X: |
1da177e4 LT |
163 | A &= X; |
164 | continue; | |
01f2f3f6 | 165 | case BPF_S_ALU_AND_K: |
93aaae2e | 166 | A &= K; |
1da177e4 | 167 | continue; |
01f2f3f6 | 168 | case BPF_S_ALU_OR_X: |
1da177e4 LT |
169 | A |= X; |
170 | continue; | |
01f2f3f6 | 171 | case BPF_S_ALU_OR_K: |
93aaae2e | 172 | A |= K; |
1da177e4 | 173 | continue; |
01f2f3f6 | 174 | case BPF_S_ALU_LSH_X: |
1da177e4 LT |
175 | A <<= X; |
176 | continue; | |
01f2f3f6 | 177 | case BPF_S_ALU_LSH_K: |
93aaae2e | 178 | A <<= K; |
1da177e4 | 179 | continue; |
01f2f3f6 | 180 | case BPF_S_ALU_RSH_X: |
1da177e4 LT |
181 | A >>= X; |
182 | continue; | |
01f2f3f6 | 183 | case BPF_S_ALU_RSH_K: |
93aaae2e | 184 | A >>= K; |
1da177e4 | 185 | continue; |
01f2f3f6 | 186 | case BPF_S_ALU_NEG: |
1da177e4 LT |
187 | A = -A; |
188 | continue; | |
01f2f3f6 | 189 | case BPF_S_JMP_JA: |
93aaae2e | 190 | fentry += K; |
1da177e4 | 191 | continue; |
01f2f3f6 | 192 | case BPF_S_JMP_JGT_K: |
93aaae2e | 193 | fentry += (A > K) ? fentry->jt : fentry->jf; |
1da177e4 | 194 | continue; |
01f2f3f6 | 195 | case BPF_S_JMP_JGE_K: |
93aaae2e | 196 | fentry += (A >= K) ? fentry->jt : fentry->jf; |
1da177e4 | 197 | continue; |
01f2f3f6 | 198 | case BPF_S_JMP_JEQ_K: |
93aaae2e | 199 | fentry += (A == K) ? fentry->jt : fentry->jf; |
1da177e4 | 200 | continue; |
01f2f3f6 | 201 | case BPF_S_JMP_JSET_K: |
93aaae2e | 202 | fentry += (A & K) ? fentry->jt : fentry->jf; |
1da177e4 | 203 | continue; |
01f2f3f6 | 204 | case BPF_S_JMP_JGT_X: |
93aaae2e | 205 | fentry += (A > X) ? fentry->jt : fentry->jf; |
1da177e4 | 206 | continue; |
01f2f3f6 | 207 | case BPF_S_JMP_JGE_X: |
93aaae2e | 208 | fentry += (A >= X) ? fentry->jt : fentry->jf; |
1da177e4 | 209 | continue; |
01f2f3f6 | 210 | case BPF_S_JMP_JEQ_X: |
93aaae2e | 211 | fentry += (A == X) ? fentry->jt : fentry->jf; |
1da177e4 | 212 | continue; |
01f2f3f6 | 213 | case BPF_S_JMP_JSET_X: |
93aaae2e | 214 | fentry += (A & X) ? fentry->jt : fentry->jf; |
1da177e4 | 215 | continue; |
01f2f3f6 | 216 | case BPF_S_LD_W_ABS: |
93aaae2e | 217 | k = K; |
e35bedf3 | 218 | load_w: |
0b05b2a4 PM |
219 | ptr = load_pointer(skb, k, 4, &tmp); |
220 | if (ptr != NULL) { | |
d3e2ce3b | 221 | A = get_unaligned_be32(ptr); |
0b05b2a4 | 222 | continue; |
1da177e4 | 223 | } |
12b16dad | 224 | return 0; |
01f2f3f6 | 225 | case BPF_S_LD_H_ABS: |
93aaae2e | 226 | k = K; |
e35bedf3 | 227 | load_h: |
0b05b2a4 PM |
228 | ptr = load_pointer(skb, k, 2, &tmp); |
229 | if (ptr != NULL) { | |
d3e2ce3b | 230 | A = get_unaligned_be16(ptr); |
0b05b2a4 | 231 | continue; |
1da177e4 | 232 | } |
12b16dad | 233 | return 0; |
01f2f3f6 | 234 | case BPF_S_LD_B_ABS: |
93aaae2e | 235 | k = K; |
1da177e4 | 236 | load_b: |
0b05b2a4 PM |
237 | ptr = load_pointer(skb, k, 1, &tmp); |
238 | if (ptr != NULL) { | |
239 | A = *(u8 *)ptr; | |
240 | continue; | |
1da177e4 | 241 | } |
12b16dad | 242 | return 0; |
01f2f3f6 | 243 | case BPF_S_LD_W_LEN: |
3154e540 | 244 | A = skb->len; |
1da177e4 | 245 | continue; |
01f2f3f6 | 246 | case BPF_S_LDX_W_LEN: |
3154e540 | 247 | X = skb->len; |
1da177e4 | 248 | continue; |
01f2f3f6 | 249 | case BPF_S_LD_W_IND: |
93aaae2e | 250 | k = X + K; |
1da177e4 | 251 | goto load_w; |
01f2f3f6 | 252 | case BPF_S_LD_H_IND: |
93aaae2e | 253 | k = X + K; |
1da177e4 | 254 | goto load_h; |
01f2f3f6 | 255 | case BPF_S_LD_B_IND: |
93aaae2e | 256 | k = X + K; |
1da177e4 | 257 | goto load_b; |
01f2f3f6 | 258 | case BPF_S_LDX_B_MSH: |
93aaae2e | 259 | ptr = load_pointer(skb, K, 1, &tmp); |
0b05b2a4 PM |
260 | if (ptr != NULL) { |
261 | X = (*(u8 *)ptr & 0xf) << 2; | |
262 | continue; | |
263 | } | |
264 | return 0; | |
01f2f3f6 | 265 | case BPF_S_LD_IMM: |
93aaae2e | 266 | A = K; |
1da177e4 | 267 | continue; |
01f2f3f6 | 268 | case BPF_S_LDX_IMM: |
93aaae2e | 269 | X = K; |
1da177e4 | 270 | continue; |
01f2f3f6 | 271 | case BPF_S_LD_MEM: |
2d5311e4 | 272 | A = mem[K]; |
1da177e4 | 273 | continue; |
01f2f3f6 | 274 | case BPF_S_LDX_MEM: |
2d5311e4 | 275 | X = mem[K]; |
1da177e4 | 276 | continue; |
01f2f3f6 | 277 | case BPF_S_MISC_TAX: |
1da177e4 LT |
278 | X = A; |
279 | continue; | |
01f2f3f6 | 280 | case BPF_S_MISC_TXA: |
1da177e4 LT |
281 | A = X; |
282 | continue; | |
01f2f3f6 | 283 | case BPF_S_RET_K: |
93aaae2e | 284 | return K; |
01f2f3f6 | 285 | case BPF_S_RET_A: |
4bad4dc9 | 286 | return A; |
01f2f3f6 | 287 | case BPF_S_ST: |
93aaae2e | 288 | mem[K] = A; |
1da177e4 | 289 | continue; |
01f2f3f6 | 290 | case BPF_S_STX: |
93aaae2e | 291 | mem[K] = X; |
1da177e4 | 292 | continue; |
12b16dad | 293 | case BPF_S_ANC_PROTOCOL: |
252e3346 | 294 | A = ntohs(skb->protocol); |
1da177e4 | 295 | continue; |
12b16dad | 296 | case BPF_S_ANC_PKTTYPE: |
1da177e4 LT |
297 | A = skb->pkt_type; |
298 | continue; | |
12b16dad | 299 | case BPF_S_ANC_IFINDEX: |
40eaf962 PLE |
300 | if (!skb->dev) |
301 | return 0; | |
1da177e4 LT |
302 | A = skb->dev->ifindex; |
303 | continue; | |
12b16dad | 304 | case BPF_S_ANC_MARK: |
7e75f93e | 305 | A = skb->mark; |
306 | continue; | |
12b16dad | 307 | case BPF_S_ANC_QUEUE: |
d19742fb ED |
308 | A = skb->queue_mapping; |
309 | continue; | |
12b16dad | 310 | case BPF_S_ANC_HATYPE: |
40eaf962 PLE |
311 | if (!skb->dev) |
312 | return 0; | |
313 | A = skb->dev->type; | |
314 | continue; | |
12b16dad | 315 | case BPF_S_ANC_RXHASH: |
da2033c2 ED |
316 | A = skb->rxhash; |
317 | continue; | |
12b16dad | 318 | case BPF_S_ANC_CPU: |
da2033c2 ED |
319 | A = raw_smp_processor_id(); |
320 | continue; | |
ffe06c17 JP |
321 | case BPF_S_ANC_ALU_XOR_X: |
322 | A ^= X; | |
323 | continue; | |
12b16dad | 324 | case BPF_S_ANC_NLATTR: { |
4738c1db PM |
325 | struct nlattr *nla; |
326 | ||
327 | if (skb_is_nonlinear(skb)) | |
328 | return 0; | |
329 | if (A > skb->len - sizeof(struct nlattr)) | |
330 | return 0; | |
331 | ||
332 | nla = nla_find((struct nlattr *)&skb->data[A], | |
333 | skb->len - A, X); | |
334 | if (nla) | |
335 | A = (void *)nla - (void *)skb->data; | |
336 | else | |
337 | A = 0; | |
338 | continue; | |
339 | } | |
12b16dad | 340 | case BPF_S_ANC_NLATTR_NEST: { |
d214c753 PNA |
341 | struct nlattr *nla; |
342 | ||
343 | if (skb_is_nonlinear(skb)) | |
344 | return 0; | |
345 | if (A > skb->len - sizeof(struct nlattr)) | |
346 | return 0; | |
347 | ||
348 | nla = (struct nlattr *)&skb->data[A]; | |
349 | if (nla->nla_len > A - skb->len) | |
350 | return 0; | |
351 | ||
352 | nla = nla_find_nested(nla, X); | |
353 | if (nla) | |
354 | A = (void *)nla - (void *)skb->data; | |
355 | else | |
356 | A = 0; | |
357 | continue; | |
358 | } | |
46b325c7 WD |
359 | #ifdef CONFIG_SECCOMP_FILTER |
360 | case BPF_S_ANC_SECCOMP_LD_W: | |
361 | A = seccomp_bpf_load(fentry->k); | |
362 | continue; | |
363 | #endif | |
1da177e4 | 364 | default: |
6c4a5cb2 JP |
365 | WARN_RATELIMIT(1, "Unknown code:%u jt:%u tf:%u k:%u\n", |
366 | fentry->code, fentry->jt, | |
367 | fentry->jf, fentry->k); | |
1da177e4 LT |
368 | return 0; |
369 | } | |
370 | } | |
371 | ||
372 | return 0; | |
373 | } | |
b715631f | 374 | EXPORT_SYMBOL(sk_run_filter); |
1da177e4 | 375 | |
2d5311e4 ED |
376 | /* |
377 | * Security : | |
378 | * A BPF program is able to use 16 cells of memory to store intermediate | |
379 | * values (check u32 mem[BPF_MEMWORDS] in sk_run_filter()) | |
380 | * As we dont want to clear mem[] array for each packet going through | |
381 | * sk_run_filter(), we check that filter loaded by user never try to read | |
382 | * a cell if not previously written, and we check all branches to be sure | |
25985edc | 383 | * a malicious user doesn't try to abuse us. |
2d5311e4 ED |
384 | */ |
385 | static int check_load_and_stores(struct sock_filter *filter, int flen) | |
386 | { | |
387 | u16 *masks, memvalid = 0; /* one bit per cell, 16 cells */ | |
388 | int pc, ret = 0; | |
389 | ||
390 | BUILD_BUG_ON(BPF_MEMWORDS > 16); | |
391 | masks = kmalloc(flen * sizeof(*masks), GFP_KERNEL); | |
392 | if (!masks) | |
393 | return -ENOMEM; | |
394 | memset(masks, 0xff, flen * sizeof(*masks)); | |
395 | ||
396 | for (pc = 0; pc < flen; pc++) { | |
397 | memvalid &= masks[pc]; | |
398 | ||
399 | switch (filter[pc].code) { | |
400 | case BPF_S_ST: | |
401 | case BPF_S_STX: | |
402 | memvalid |= (1 << filter[pc].k); | |
403 | break; | |
404 | case BPF_S_LD_MEM: | |
405 | case BPF_S_LDX_MEM: | |
406 | if (!(memvalid & (1 << filter[pc].k))) { | |
407 | ret = -EINVAL; | |
408 | goto error; | |
409 | } | |
410 | break; | |
411 | case BPF_S_JMP_JA: | |
412 | /* a jump must set masks on target */ | |
413 | masks[pc + 1 + filter[pc].k] &= memvalid; | |
414 | memvalid = ~0; | |
415 | break; | |
416 | case BPF_S_JMP_JEQ_K: | |
417 | case BPF_S_JMP_JEQ_X: | |
418 | case BPF_S_JMP_JGE_K: | |
419 | case BPF_S_JMP_JGE_X: | |
420 | case BPF_S_JMP_JGT_K: | |
421 | case BPF_S_JMP_JGT_X: | |
422 | case BPF_S_JMP_JSET_X: | |
423 | case BPF_S_JMP_JSET_K: | |
424 | /* a jump must set masks on targets */ | |
425 | masks[pc + 1 + filter[pc].jt] &= memvalid; | |
426 | masks[pc + 1 + filter[pc].jf] &= memvalid; | |
427 | memvalid = ~0; | |
428 | break; | |
429 | } | |
430 | } | |
431 | error: | |
432 | kfree(masks); | |
433 | return ret; | |
434 | } | |
435 | ||
1da177e4 LT |
436 | /** |
437 | * sk_chk_filter - verify socket filter code | |
438 | * @filter: filter to verify | |
439 | * @flen: length of filter | |
440 | * | |
441 | * Check the user's filter code. If we let some ugly | |
442 | * filter code slip through kaboom! The filter must contain | |
93699863 KK |
443 | * no references or jumps that are out of range, no illegal |
444 | * instructions, and must end with a RET instruction. | |
1da177e4 | 445 | * |
7b11f69f KK |
446 | * All jumps are forward as they are not signed. |
447 | * | |
448 | * Returns 0 if the rule set is legal or -EINVAL if not. | |
1da177e4 | 449 | */ |
4f25af27 | 450 | int sk_chk_filter(struct sock_filter *filter, unsigned int flen) |
1da177e4 | 451 | { |
cba328fc TH |
452 | /* |
453 | * Valid instructions are initialized to non-0. | |
454 | * Invalid instructions are initialized to 0. | |
455 | */ | |
456 | static const u8 codes[] = { | |
8c1592d6 ED |
457 | [BPF_ALU|BPF_ADD|BPF_K] = BPF_S_ALU_ADD_K, |
458 | [BPF_ALU|BPF_ADD|BPF_X] = BPF_S_ALU_ADD_X, | |
459 | [BPF_ALU|BPF_SUB|BPF_K] = BPF_S_ALU_SUB_K, | |
460 | [BPF_ALU|BPF_SUB|BPF_X] = BPF_S_ALU_SUB_X, | |
461 | [BPF_ALU|BPF_MUL|BPF_K] = BPF_S_ALU_MUL_K, | |
462 | [BPF_ALU|BPF_MUL|BPF_X] = BPF_S_ALU_MUL_X, | |
463 | [BPF_ALU|BPF_DIV|BPF_X] = BPF_S_ALU_DIV_X, | |
464 | [BPF_ALU|BPF_AND|BPF_K] = BPF_S_ALU_AND_K, | |
465 | [BPF_ALU|BPF_AND|BPF_X] = BPF_S_ALU_AND_X, | |
466 | [BPF_ALU|BPF_OR|BPF_K] = BPF_S_ALU_OR_K, | |
467 | [BPF_ALU|BPF_OR|BPF_X] = BPF_S_ALU_OR_X, | |
468 | [BPF_ALU|BPF_LSH|BPF_K] = BPF_S_ALU_LSH_K, | |
469 | [BPF_ALU|BPF_LSH|BPF_X] = BPF_S_ALU_LSH_X, | |
470 | [BPF_ALU|BPF_RSH|BPF_K] = BPF_S_ALU_RSH_K, | |
471 | [BPF_ALU|BPF_RSH|BPF_X] = BPF_S_ALU_RSH_X, | |
472 | [BPF_ALU|BPF_NEG] = BPF_S_ALU_NEG, | |
473 | [BPF_LD|BPF_W|BPF_ABS] = BPF_S_LD_W_ABS, | |
474 | [BPF_LD|BPF_H|BPF_ABS] = BPF_S_LD_H_ABS, | |
475 | [BPF_LD|BPF_B|BPF_ABS] = BPF_S_LD_B_ABS, | |
476 | [BPF_LD|BPF_W|BPF_LEN] = BPF_S_LD_W_LEN, | |
477 | [BPF_LD|BPF_W|BPF_IND] = BPF_S_LD_W_IND, | |
478 | [BPF_LD|BPF_H|BPF_IND] = BPF_S_LD_H_IND, | |
479 | [BPF_LD|BPF_B|BPF_IND] = BPF_S_LD_B_IND, | |
480 | [BPF_LD|BPF_IMM] = BPF_S_LD_IMM, | |
481 | [BPF_LDX|BPF_W|BPF_LEN] = BPF_S_LDX_W_LEN, | |
482 | [BPF_LDX|BPF_B|BPF_MSH] = BPF_S_LDX_B_MSH, | |
483 | [BPF_LDX|BPF_IMM] = BPF_S_LDX_IMM, | |
484 | [BPF_MISC|BPF_TAX] = BPF_S_MISC_TAX, | |
485 | [BPF_MISC|BPF_TXA] = BPF_S_MISC_TXA, | |
486 | [BPF_RET|BPF_K] = BPF_S_RET_K, | |
487 | [BPF_RET|BPF_A] = BPF_S_RET_A, | |
488 | [BPF_ALU|BPF_DIV|BPF_K] = BPF_S_ALU_DIV_K, | |
489 | [BPF_LD|BPF_MEM] = BPF_S_LD_MEM, | |
490 | [BPF_LDX|BPF_MEM] = BPF_S_LDX_MEM, | |
491 | [BPF_ST] = BPF_S_ST, | |
492 | [BPF_STX] = BPF_S_STX, | |
493 | [BPF_JMP|BPF_JA] = BPF_S_JMP_JA, | |
494 | [BPF_JMP|BPF_JEQ|BPF_K] = BPF_S_JMP_JEQ_K, | |
495 | [BPF_JMP|BPF_JEQ|BPF_X] = BPF_S_JMP_JEQ_X, | |
496 | [BPF_JMP|BPF_JGE|BPF_K] = BPF_S_JMP_JGE_K, | |
497 | [BPF_JMP|BPF_JGE|BPF_X] = BPF_S_JMP_JGE_X, | |
498 | [BPF_JMP|BPF_JGT|BPF_K] = BPF_S_JMP_JGT_K, | |
499 | [BPF_JMP|BPF_JGT|BPF_X] = BPF_S_JMP_JGT_X, | |
500 | [BPF_JMP|BPF_JSET|BPF_K] = BPF_S_JMP_JSET_K, | |
501 | [BPF_JMP|BPF_JSET|BPF_X] = BPF_S_JMP_JSET_X, | |
cba328fc | 502 | }; |
1da177e4 LT |
503 | int pc; |
504 | ||
1b93ae64 | 505 | if (flen == 0 || flen > BPF_MAXINSNS) |
1da177e4 LT |
506 | return -EINVAL; |
507 | ||
508 | /* check the filter code now */ | |
509 | for (pc = 0; pc < flen; pc++) { | |
cba328fc TH |
510 | struct sock_filter *ftest = &filter[pc]; |
511 | u16 code = ftest->code; | |
93699863 | 512 | |
cba328fc TH |
513 | if (code >= ARRAY_SIZE(codes)) |
514 | return -EINVAL; | |
515 | code = codes[code]; | |
8c1592d6 | 516 | if (!code) |
cba328fc | 517 | return -EINVAL; |
93699863 | 518 | /* Some instructions need special checks */ |
cba328fc TH |
519 | switch (code) { |
520 | case BPF_S_ALU_DIV_K: | |
93699863 KK |
521 | /* check for division by zero */ |
522 | if (ftest->k == 0) | |
1da177e4 | 523 | return -EINVAL; |
c26aed40 | 524 | ftest->k = reciprocal_value(ftest->k); |
93699863 | 525 | break; |
cba328fc TH |
526 | case BPF_S_LD_MEM: |
527 | case BPF_S_LDX_MEM: | |
528 | case BPF_S_ST: | |
529 | case BPF_S_STX: | |
530 | /* check for invalid memory addresses */ | |
93699863 KK |
531 | if (ftest->k >= BPF_MEMWORDS) |
532 | return -EINVAL; | |
533 | break; | |
cba328fc | 534 | case BPF_S_JMP_JA: |
93699863 KK |
535 | /* |
536 | * Note, the large ftest->k might cause loops. | |
537 | * Compare this with conditional jumps below, | |
538 | * where offsets are limited. --ANK (981016) | |
539 | */ | |
95c96174 | 540 | if (ftest->k >= (unsigned int)(flen-pc-1)) |
93699863 | 541 | return -EINVAL; |
01f2f3f6 | 542 | break; |
01f2f3f6 HPP |
543 | case BPF_S_JMP_JEQ_K: |
544 | case BPF_S_JMP_JEQ_X: | |
545 | case BPF_S_JMP_JGE_K: | |
546 | case BPF_S_JMP_JGE_X: | |
547 | case BPF_S_JMP_JGT_K: | |
548 | case BPF_S_JMP_JGT_X: | |
549 | case BPF_S_JMP_JSET_X: | |
550 | case BPF_S_JMP_JSET_K: | |
cba328fc | 551 | /* for conditionals both must be safe */ |
e35bedf3 | 552 | if (pc + ftest->jt + 1 >= flen || |
93699863 KK |
553 | pc + ftest->jf + 1 >= flen) |
554 | return -EINVAL; | |
cba328fc | 555 | break; |
12b16dad ED |
556 | case BPF_S_LD_W_ABS: |
557 | case BPF_S_LD_H_ABS: | |
558 | case BPF_S_LD_B_ABS: | |
559 | #define ANCILLARY(CODE) case SKF_AD_OFF + SKF_AD_##CODE: \ | |
560 | code = BPF_S_ANC_##CODE; \ | |
561 | break | |
562 | switch (ftest->k) { | |
563 | ANCILLARY(PROTOCOL); | |
564 | ANCILLARY(PKTTYPE); | |
565 | ANCILLARY(IFINDEX); | |
566 | ANCILLARY(NLATTR); | |
567 | ANCILLARY(NLATTR_NEST); | |
568 | ANCILLARY(MARK); | |
569 | ANCILLARY(QUEUE); | |
570 | ANCILLARY(HATYPE); | |
571 | ANCILLARY(RXHASH); | |
572 | ANCILLARY(CPU); | |
ffe06c17 | 573 | ANCILLARY(ALU_XOR_X); |
12b16dad | 574 | } |
01f2f3f6 | 575 | } |
cba328fc | 576 | ftest->code = code; |
01f2f3f6 | 577 | } |
93699863 | 578 | |
01f2f3f6 HPP |
579 | /* last instruction must be a RET code */ |
580 | switch (filter[flen - 1].code) { | |
581 | case BPF_S_RET_K: | |
582 | case BPF_S_RET_A: | |
2d5311e4 | 583 | return check_load_and_stores(filter, flen); |
cba328fc TH |
584 | } |
585 | return -EINVAL; | |
1da177e4 | 586 | } |
b715631f | 587 | EXPORT_SYMBOL(sk_chk_filter); |
1da177e4 | 588 | |
47e958ea | 589 | /** |
46bcf14f | 590 | * sk_filter_release_rcu - Release a socket filter by rcu_head |
47e958ea PE |
591 | * @rcu: rcu_head that contains the sk_filter to free |
592 | */ | |
46bcf14f | 593 | void sk_filter_release_rcu(struct rcu_head *rcu) |
47e958ea PE |
594 | { |
595 | struct sk_filter *fp = container_of(rcu, struct sk_filter, rcu); | |
596 | ||
0a14842f | 597 | bpf_jit_free(fp); |
46bcf14f | 598 | kfree(fp); |
47e958ea | 599 | } |
46bcf14f | 600 | EXPORT_SYMBOL(sk_filter_release_rcu); |
47e958ea | 601 | |
302d6637 JP |
602 | static int __sk_prepare_filter(struct sk_filter *fp) |
603 | { | |
604 | int err; | |
605 | ||
606 | fp->bpf_func = sk_run_filter; | |
607 | ||
608 | err = sk_chk_filter(fp->insns, fp->len); | |
609 | if (err) | |
610 | return err; | |
611 | ||
612 | bpf_jit_compile(fp); | |
613 | return 0; | |
614 | } | |
615 | ||
616 | /** | |
617 | * sk_unattached_filter_create - create an unattached filter | |
618 | * @fprog: the filter program | |
c6c4b97c | 619 | * @pfp: the unattached filter that is created |
302d6637 | 620 | * |
c6c4b97c | 621 | * Create a filter independent of any socket. We first run some |
302d6637 JP |
622 | * sanity checks on it to make sure it does not explode on us later. |
623 | * If an error occurs or there is insufficient memory for the filter | |
624 | * a negative errno code is returned. On success the return is zero. | |
625 | */ | |
626 | int sk_unattached_filter_create(struct sk_filter **pfp, | |
627 | struct sock_fprog *fprog) | |
628 | { | |
629 | struct sk_filter *fp; | |
630 | unsigned int fsize = sizeof(struct sock_filter) * fprog->len; | |
631 | int err; | |
632 | ||
633 | /* Make sure new filter is there and in the right amounts. */ | |
634 | if (fprog->filter == NULL) | |
635 | return -EINVAL; | |
636 | ||
637 | fp = kmalloc(fsize + sizeof(*fp), GFP_KERNEL); | |
638 | if (!fp) | |
639 | return -ENOMEM; | |
640 | memcpy(fp->insns, fprog->filter, fsize); | |
641 | ||
642 | atomic_set(&fp->refcnt, 1); | |
643 | fp->len = fprog->len; | |
644 | ||
645 | err = __sk_prepare_filter(fp); | |
646 | if (err) | |
647 | goto free_mem; | |
648 | ||
649 | *pfp = fp; | |
650 | return 0; | |
651 | free_mem: | |
652 | kfree(fp); | |
653 | return err; | |
654 | } | |
655 | EXPORT_SYMBOL_GPL(sk_unattached_filter_create); | |
656 | ||
657 | void sk_unattached_filter_destroy(struct sk_filter *fp) | |
658 | { | |
659 | sk_filter_release(fp); | |
660 | } | |
661 | EXPORT_SYMBOL_GPL(sk_unattached_filter_destroy); | |
662 | ||
1da177e4 LT |
663 | /** |
664 | * sk_attach_filter - attach a socket filter | |
665 | * @fprog: the filter program | |
666 | * @sk: the socket to use | |
667 | * | |
668 | * Attach the user's filter code. We first run some sanity checks on | |
669 | * it to make sure it does not explode on us later. If an error | |
670 | * occurs or there is insufficient memory for the filter a negative | |
671 | * errno code is returned. On success the return is zero. | |
672 | */ | |
673 | int sk_attach_filter(struct sock_fprog *fprog, struct sock *sk) | |
674 | { | |
d3904b73 | 675 | struct sk_filter *fp, *old_fp; |
1da177e4 LT |
676 | unsigned int fsize = sizeof(struct sock_filter) * fprog->len; |
677 | int err; | |
678 | ||
679 | /* Make sure new filter is there and in the right amounts. */ | |
e35bedf3 KK |
680 | if (fprog->filter == NULL) |
681 | return -EINVAL; | |
1da177e4 LT |
682 | |
683 | fp = sock_kmalloc(sk, fsize+sizeof(*fp), GFP_KERNEL); | |
684 | if (!fp) | |
685 | return -ENOMEM; | |
686 | if (copy_from_user(fp->insns, fprog->filter, fsize)) { | |
4ec93edb | 687 | sock_kfree_s(sk, fp, fsize+sizeof(*fp)); |
1da177e4 LT |
688 | return -EFAULT; |
689 | } | |
690 | ||
691 | atomic_set(&fp->refcnt, 1); | |
692 | fp->len = fprog->len; | |
693 | ||
302d6637 | 694 | err = __sk_prepare_filter(fp); |
d3904b73 PE |
695 | if (err) { |
696 | sk_filter_uncharge(sk, fp); | |
697 | return err; | |
1da177e4 LT |
698 | } |
699 | ||
f91ff5b9 ED |
700 | old_fp = rcu_dereference_protected(sk->sk_filter, |
701 | sock_owned_by_user(sk)); | |
d3904b73 | 702 | rcu_assign_pointer(sk->sk_filter, fp); |
d3904b73 | 703 | |
9b013e05 | 704 | if (old_fp) |
46bcf14f | 705 | sk_filter_uncharge(sk, old_fp); |
d3904b73 | 706 | return 0; |
1da177e4 | 707 | } |
5ff3f073 | 708 | EXPORT_SYMBOL_GPL(sk_attach_filter); |
1da177e4 | 709 | |
55b33325 PE |
710 | int sk_detach_filter(struct sock *sk) |
711 | { | |
712 | int ret = -ENOENT; | |
713 | struct sk_filter *filter; | |
714 | ||
f91ff5b9 ED |
715 | filter = rcu_dereference_protected(sk->sk_filter, |
716 | sock_owned_by_user(sk)); | |
55b33325 | 717 | if (filter) { |
a9b3cd7f | 718 | RCU_INIT_POINTER(sk->sk_filter, NULL); |
46bcf14f | 719 | sk_filter_uncharge(sk, filter); |
55b33325 PE |
720 | ret = 0; |
721 | } | |
55b33325 PE |
722 | return ret; |
723 | } | |
5ff3f073 | 724 | EXPORT_SYMBOL_GPL(sk_detach_filter); |