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> | |
36 | #include <asm/system.h> | |
37 | #include <asm/uaccess.h> | |
40daafc8 | 38 | #include <asm/unaligned.h> |
1da177e4 | 39 | #include <linux/filter.h> |
c26aed40 | 40 | #include <linux/reciprocal_div.h> |
1da177e4 | 41 | |
4c3710af | 42 | enum { |
8c1592d6 | 43 | BPF_S_RET_K = 1, |
4c3710af CG |
44 | BPF_S_RET_A, |
45 | BPF_S_ALU_ADD_K, | |
46 | BPF_S_ALU_ADD_X, | |
47 | BPF_S_ALU_SUB_K, | |
48 | BPF_S_ALU_SUB_X, | |
49 | BPF_S_ALU_MUL_K, | |
50 | BPF_S_ALU_MUL_X, | |
51 | BPF_S_ALU_DIV_X, | |
52 | BPF_S_ALU_AND_K, | |
53 | BPF_S_ALU_AND_X, | |
54 | BPF_S_ALU_OR_K, | |
55 | BPF_S_ALU_OR_X, | |
56 | BPF_S_ALU_LSH_K, | |
57 | BPF_S_ALU_LSH_X, | |
58 | BPF_S_ALU_RSH_K, | |
59 | BPF_S_ALU_RSH_X, | |
60 | BPF_S_ALU_NEG, | |
61 | BPF_S_LD_W_ABS, | |
62 | BPF_S_LD_H_ABS, | |
63 | BPF_S_LD_B_ABS, | |
64 | BPF_S_LD_W_LEN, | |
65 | BPF_S_LD_W_IND, | |
66 | BPF_S_LD_H_IND, | |
67 | BPF_S_LD_B_IND, | |
68 | BPF_S_LD_IMM, | |
69 | BPF_S_LDX_W_LEN, | |
70 | BPF_S_LDX_B_MSH, | |
71 | BPF_S_LDX_IMM, | |
72 | BPF_S_MISC_TAX, | |
73 | BPF_S_MISC_TXA, | |
74 | BPF_S_ALU_DIV_K, | |
75 | BPF_S_LD_MEM, | |
76 | BPF_S_LDX_MEM, | |
77 | BPF_S_ST, | |
78 | BPF_S_STX, | |
79 | BPF_S_JMP_JA, | |
80 | BPF_S_JMP_JEQ_K, | |
81 | BPF_S_JMP_JEQ_X, | |
82 | BPF_S_JMP_JGE_K, | |
83 | BPF_S_JMP_JGE_X, | |
84 | BPF_S_JMP_JGT_K, | |
85 | BPF_S_JMP_JGT_X, | |
86 | BPF_S_JMP_JSET_K, | |
87 | BPF_S_JMP_JSET_X, | |
12b16dad ED |
88 | /* Ancillary data */ |
89 | BPF_S_ANC_PROTOCOL, | |
90 | BPF_S_ANC_PKTTYPE, | |
91 | BPF_S_ANC_IFINDEX, | |
92 | BPF_S_ANC_NLATTR, | |
93 | BPF_S_ANC_NLATTR_NEST, | |
94 | BPF_S_ANC_MARK, | |
95 | BPF_S_ANC_QUEUE, | |
96 | BPF_S_ANC_HATYPE, | |
97 | BPF_S_ANC_RXHASH, | |
98 | BPF_S_ANC_CPU, | |
4c3710af CG |
99 | }; |
100 | ||
1da177e4 | 101 | /* No hurry in this branch */ |
4bc65dd8 | 102 | static void *__load_pointer(const struct sk_buff *skb, int k, unsigned int size) |
1da177e4 LT |
103 | { |
104 | u8 *ptr = NULL; | |
105 | ||
106 | if (k >= SKF_NET_OFF) | |
d56f90a7 | 107 | ptr = skb_network_header(skb) + k - SKF_NET_OFF; |
1da177e4 | 108 | else if (k >= SKF_LL_OFF) |
98e399f8 | 109 | ptr = skb_mac_header(skb) + k - SKF_LL_OFF; |
1da177e4 | 110 | |
4bc65dd8 | 111 | if (ptr >= skb->head && ptr + size <= skb_tail_pointer(skb)) |
1da177e4 LT |
112 | return ptr; |
113 | return NULL; | |
114 | } | |
115 | ||
62ab0812 | 116 | static inline void *load_pointer(const struct sk_buff *skb, int k, |
4ec93edb | 117 | unsigned int size, void *buffer) |
0b05b2a4 PM |
118 | { |
119 | if (k >= 0) | |
120 | return skb_header_pointer(skb, k, size, buffer); | |
12b16dad | 121 | return __load_pointer(skb, k, size); |
0b05b2a4 PM |
122 | } |
123 | ||
43db6d65 SH |
124 | /** |
125 | * sk_filter - run a packet through a socket filter | |
126 | * @sk: sock associated with &sk_buff | |
127 | * @skb: buffer to filter | |
43db6d65 SH |
128 | * |
129 | * Run the filter code and then cut skb->data to correct size returned by | |
130 | * sk_run_filter. If pkt_len is 0 we toss packet. If skb->len is smaller | |
131 | * than pkt_len we keep whole skb->data. This is the socket level | |
132 | * wrapper to sk_run_filter. It returns 0 if the packet should | |
133 | * be accepted or -EPERM if the packet should be tossed. | |
134 | * | |
135 | */ | |
136 | int sk_filter(struct sock *sk, struct sk_buff *skb) | |
137 | { | |
138 | int err; | |
139 | struct sk_filter *filter; | |
140 | ||
141 | err = security_sock_rcv_skb(sk, skb); | |
142 | if (err) | |
143 | return err; | |
144 | ||
145 | rcu_read_lock_bh(); | |
a898def2 | 146 | filter = rcu_dereference_bh(sk->sk_filter); |
43db6d65 | 147 | if (filter) { |
93aaae2e | 148 | unsigned int pkt_len = sk_run_filter(skb, filter->insns); |
0d7da9dd | 149 | |
43db6d65 SH |
150 | err = pkt_len ? pskb_trim(skb, pkt_len) : -EPERM; |
151 | } | |
152 | rcu_read_unlock_bh(); | |
153 | ||
154 | return err; | |
155 | } | |
156 | EXPORT_SYMBOL(sk_filter); | |
157 | ||
1da177e4 | 158 | /** |
2966b66c | 159 | * sk_run_filter - run a filter on a socket |
1da177e4 LT |
160 | * @skb: buffer to run the filter on |
161 | * @filter: filter to apply | |
1da177e4 LT |
162 | * |
163 | * Decode and apply filter instructions to the skb->data. | |
93aaae2e ED |
164 | * Return length to keep, 0 for none. @skb is the data we are |
165 | * filtering, @filter is the array of filter instructions. | |
166 | * Because all jumps are guaranteed to be before last instruction, | |
167 | * and last instruction guaranteed to be a RET, we dont need to check | |
168 | * flen. (We used to pass to this function the length of filter) | |
1da177e4 | 169 | */ |
62ab0812 ED |
170 | unsigned int sk_run_filter(const struct sk_buff *skb, |
171 | const struct sock_filter *fentry) | |
1da177e4 | 172 | { |
0b05b2a4 | 173 | void *ptr; |
2966b66c KK |
174 | u32 A = 0; /* Accumulator */ |
175 | u32 X = 0; /* Index Register */ | |
1da177e4 | 176 | u32 mem[BPF_MEMWORDS]; /* Scratch Memory Store */ |
0b05b2a4 | 177 | u32 tmp; |
1da177e4 | 178 | int k; |
1da177e4 LT |
179 | |
180 | /* | |
181 | * Process array of filter instructions. | |
182 | */ | |
93aaae2e ED |
183 | for (;; fentry++) { |
184 | #if defined(CONFIG_X86_32) | |
185 | #define K (fentry->k) | |
186 | #else | |
187 | const u32 K = fentry->k; | |
188 | #endif | |
4ec93edb | 189 | |
1da177e4 | 190 | switch (fentry->code) { |
01f2f3f6 | 191 | case BPF_S_ALU_ADD_X: |
1da177e4 LT |
192 | A += X; |
193 | continue; | |
01f2f3f6 | 194 | case BPF_S_ALU_ADD_K: |
93aaae2e | 195 | A += K; |
1da177e4 | 196 | continue; |
01f2f3f6 | 197 | case BPF_S_ALU_SUB_X: |
1da177e4 LT |
198 | A -= X; |
199 | continue; | |
01f2f3f6 | 200 | case BPF_S_ALU_SUB_K: |
93aaae2e | 201 | A -= K; |
1da177e4 | 202 | continue; |
01f2f3f6 | 203 | case BPF_S_ALU_MUL_X: |
1da177e4 LT |
204 | A *= X; |
205 | continue; | |
01f2f3f6 | 206 | case BPF_S_ALU_MUL_K: |
93aaae2e | 207 | A *= K; |
1da177e4 | 208 | continue; |
01f2f3f6 | 209 | case BPF_S_ALU_DIV_X: |
1da177e4 LT |
210 | if (X == 0) |
211 | return 0; | |
212 | A /= X; | |
213 | continue; | |
01f2f3f6 | 214 | case BPF_S_ALU_DIV_K: |
c26aed40 | 215 | A = reciprocal_divide(A, K); |
1da177e4 | 216 | continue; |
01f2f3f6 | 217 | case BPF_S_ALU_AND_X: |
1da177e4 LT |
218 | A &= X; |
219 | continue; | |
01f2f3f6 | 220 | case BPF_S_ALU_AND_K: |
93aaae2e | 221 | A &= K; |
1da177e4 | 222 | continue; |
01f2f3f6 | 223 | case BPF_S_ALU_OR_X: |
1da177e4 LT |
224 | A |= X; |
225 | continue; | |
01f2f3f6 | 226 | case BPF_S_ALU_OR_K: |
93aaae2e | 227 | A |= K; |
1da177e4 | 228 | continue; |
01f2f3f6 | 229 | case BPF_S_ALU_LSH_X: |
1da177e4 LT |
230 | A <<= X; |
231 | continue; | |
01f2f3f6 | 232 | case BPF_S_ALU_LSH_K: |
93aaae2e | 233 | A <<= K; |
1da177e4 | 234 | continue; |
01f2f3f6 | 235 | case BPF_S_ALU_RSH_X: |
1da177e4 LT |
236 | A >>= X; |
237 | continue; | |
01f2f3f6 | 238 | case BPF_S_ALU_RSH_K: |
93aaae2e | 239 | A >>= K; |
1da177e4 | 240 | continue; |
01f2f3f6 | 241 | case BPF_S_ALU_NEG: |
1da177e4 LT |
242 | A = -A; |
243 | continue; | |
01f2f3f6 | 244 | case BPF_S_JMP_JA: |
93aaae2e | 245 | fentry += K; |
1da177e4 | 246 | continue; |
01f2f3f6 | 247 | case BPF_S_JMP_JGT_K: |
93aaae2e | 248 | fentry += (A > K) ? fentry->jt : fentry->jf; |
1da177e4 | 249 | continue; |
01f2f3f6 | 250 | case BPF_S_JMP_JGE_K: |
93aaae2e | 251 | fentry += (A >= K) ? fentry->jt : fentry->jf; |
1da177e4 | 252 | continue; |
01f2f3f6 | 253 | case BPF_S_JMP_JEQ_K: |
93aaae2e | 254 | fentry += (A == K) ? fentry->jt : fentry->jf; |
1da177e4 | 255 | continue; |
01f2f3f6 | 256 | case BPF_S_JMP_JSET_K: |
93aaae2e | 257 | fentry += (A & K) ? fentry->jt : fentry->jf; |
1da177e4 | 258 | continue; |
01f2f3f6 | 259 | case BPF_S_JMP_JGT_X: |
93aaae2e | 260 | fentry += (A > X) ? fentry->jt : fentry->jf; |
1da177e4 | 261 | continue; |
01f2f3f6 | 262 | case BPF_S_JMP_JGE_X: |
93aaae2e | 263 | fentry += (A >= X) ? fentry->jt : fentry->jf; |
1da177e4 | 264 | continue; |
01f2f3f6 | 265 | case BPF_S_JMP_JEQ_X: |
93aaae2e | 266 | fentry += (A == X) ? fentry->jt : fentry->jf; |
1da177e4 | 267 | continue; |
01f2f3f6 | 268 | case BPF_S_JMP_JSET_X: |
93aaae2e | 269 | fentry += (A & X) ? fentry->jt : fentry->jf; |
1da177e4 | 270 | continue; |
01f2f3f6 | 271 | case BPF_S_LD_W_ABS: |
93aaae2e | 272 | k = K; |
e35bedf3 | 273 | load_w: |
0b05b2a4 PM |
274 | ptr = load_pointer(skb, k, 4, &tmp); |
275 | if (ptr != NULL) { | |
d3e2ce3b | 276 | A = get_unaligned_be32(ptr); |
0b05b2a4 | 277 | continue; |
1da177e4 | 278 | } |
12b16dad | 279 | return 0; |
01f2f3f6 | 280 | case BPF_S_LD_H_ABS: |
93aaae2e | 281 | k = K; |
e35bedf3 | 282 | load_h: |
0b05b2a4 PM |
283 | ptr = load_pointer(skb, k, 2, &tmp); |
284 | if (ptr != NULL) { | |
d3e2ce3b | 285 | A = get_unaligned_be16(ptr); |
0b05b2a4 | 286 | continue; |
1da177e4 | 287 | } |
12b16dad | 288 | return 0; |
01f2f3f6 | 289 | case BPF_S_LD_B_ABS: |
93aaae2e | 290 | k = K; |
1da177e4 | 291 | load_b: |
0b05b2a4 PM |
292 | ptr = load_pointer(skb, k, 1, &tmp); |
293 | if (ptr != NULL) { | |
294 | A = *(u8 *)ptr; | |
295 | continue; | |
1da177e4 | 296 | } |
12b16dad | 297 | return 0; |
01f2f3f6 | 298 | case BPF_S_LD_W_LEN: |
3154e540 | 299 | A = skb->len; |
1da177e4 | 300 | continue; |
01f2f3f6 | 301 | case BPF_S_LDX_W_LEN: |
3154e540 | 302 | X = skb->len; |
1da177e4 | 303 | continue; |
01f2f3f6 | 304 | case BPF_S_LD_W_IND: |
93aaae2e | 305 | k = X + K; |
1da177e4 | 306 | goto load_w; |
01f2f3f6 | 307 | case BPF_S_LD_H_IND: |
93aaae2e | 308 | k = X + K; |
1da177e4 | 309 | goto load_h; |
01f2f3f6 | 310 | case BPF_S_LD_B_IND: |
93aaae2e | 311 | k = X + K; |
1da177e4 | 312 | goto load_b; |
01f2f3f6 | 313 | case BPF_S_LDX_B_MSH: |
93aaae2e | 314 | ptr = load_pointer(skb, K, 1, &tmp); |
0b05b2a4 PM |
315 | if (ptr != NULL) { |
316 | X = (*(u8 *)ptr & 0xf) << 2; | |
317 | continue; | |
318 | } | |
319 | return 0; | |
01f2f3f6 | 320 | case BPF_S_LD_IMM: |
93aaae2e | 321 | A = K; |
1da177e4 | 322 | continue; |
01f2f3f6 | 323 | case BPF_S_LDX_IMM: |
93aaae2e | 324 | X = K; |
1da177e4 | 325 | continue; |
01f2f3f6 | 326 | case BPF_S_LD_MEM: |
2d5311e4 | 327 | A = mem[K]; |
1da177e4 | 328 | continue; |
01f2f3f6 | 329 | case BPF_S_LDX_MEM: |
2d5311e4 | 330 | X = mem[K]; |
1da177e4 | 331 | continue; |
01f2f3f6 | 332 | case BPF_S_MISC_TAX: |
1da177e4 LT |
333 | X = A; |
334 | continue; | |
01f2f3f6 | 335 | case BPF_S_MISC_TXA: |
1da177e4 LT |
336 | A = X; |
337 | continue; | |
01f2f3f6 | 338 | case BPF_S_RET_K: |
93aaae2e | 339 | return K; |
01f2f3f6 | 340 | case BPF_S_RET_A: |
4bad4dc9 | 341 | return A; |
01f2f3f6 | 342 | case BPF_S_ST: |
93aaae2e | 343 | mem[K] = A; |
1da177e4 | 344 | continue; |
01f2f3f6 | 345 | case BPF_S_STX: |
93aaae2e | 346 | mem[K] = X; |
1da177e4 | 347 | continue; |
12b16dad | 348 | case BPF_S_ANC_PROTOCOL: |
252e3346 | 349 | A = ntohs(skb->protocol); |
1da177e4 | 350 | continue; |
12b16dad | 351 | case BPF_S_ANC_PKTTYPE: |
1da177e4 LT |
352 | A = skb->pkt_type; |
353 | continue; | |
12b16dad | 354 | case BPF_S_ANC_IFINDEX: |
40eaf962 PLE |
355 | if (!skb->dev) |
356 | return 0; | |
1da177e4 LT |
357 | A = skb->dev->ifindex; |
358 | continue; | |
12b16dad | 359 | case BPF_S_ANC_MARK: |
7e75f93e | 360 | A = skb->mark; |
361 | continue; | |
12b16dad | 362 | case BPF_S_ANC_QUEUE: |
d19742fb ED |
363 | A = skb->queue_mapping; |
364 | continue; | |
12b16dad | 365 | case BPF_S_ANC_HATYPE: |
40eaf962 PLE |
366 | if (!skb->dev) |
367 | return 0; | |
368 | A = skb->dev->type; | |
369 | continue; | |
12b16dad | 370 | case BPF_S_ANC_RXHASH: |
da2033c2 ED |
371 | A = skb->rxhash; |
372 | continue; | |
12b16dad | 373 | case BPF_S_ANC_CPU: |
da2033c2 ED |
374 | A = raw_smp_processor_id(); |
375 | continue; | |
12b16dad | 376 | case BPF_S_ANC_NLATTR: { |
4738c1db PM |
377 | struct nlattr *nla; |
378 | ||
379 | if (skb_is_nonlinear(skb)) | |
380 | return 0; | |
381 | if (A > skb->len - sizeof(struct nlattr)) | |
382 | return 0; | |
383 | ||
384 | nla = nla_find((struct nlattr *)&skb->data[A], | |
385 | skb->len - A, X); | |
386 | if (nla) | |
387 | A = (void *)nla - (void *)skb->data; | |
388 | else | |
389 | A = 0; | |
390 | continue; | |
391 | } | |
12b16dad | 392 | case BPF_S_ANC_NLATTR_NEST: { |
d214c753 PNA |
393 | struct nlattr *nla; |
394 | ||
395 | if (skb_is_nonlinear(skb)) | |
396 | return 0; | |
397 | if (A > skb->len - sizeof(struct nlattr)) | |
398 | return 0; | |
399 | ||
400 | nla = (struct nlattr *)&skb->data[A]; | |
401 | if (nla->nla_len > A - skb->len) | |
402 | return 0; | |
403 | ||
404 | nla = nla_find_nested(nla, X); | |
405 | if (nla) | |
406 | A = (void *)nla - (void *)skb->data; | |
407 | else | |
408 | A = 0; | |
409 | continue; | |
410 | } | |
1da177e4 | 411 | default: |
12b16dad | 412 | WARN_ON(1); |
1da177e4 LT |
413 | return 0; |
414 | } | |
415 | } | |
416 | ||
417 | return 0; | |
418 | } | |
b715631f | 419 | EXPORT_SYMBOL(sk_run_filter); |
1da177e4 | 420 | |
2d5311e4 ED |
421 | /* |
422 | * Security : | |
423 | * A BPF program is able to use 16 cells of memory to store intermediate | |
424 | * values (check u32 mem[BPF_MEMWORDS] in sk_run_filter()) | |
425 | * As we dont want to clear mem[] array for each packet going through | |
426 | * sk_run_filter(), we check that filter loaded by user never try to read | |
427 | * a cell if not previously written, and we check all branches to be sure | |
428 | * a malicious user doesnt try to abuse us. | |
429 | */ | |
430 | static int check_load_and_stores(struct sock_filter *filter, int flen) | |
431 | { | |
432 | u16 *masks, memvalid = 0; /* one bit per cell, 16 cells */ | |
433 | int pc, ret = 0; | |
434 | ||
435 | BUILD_BUG_ON(BPF_MEMWORDS > 16); | |
436 | masks = kmalloc(flen * sizeof(*masks), GFP_KERNEL); | |
437 | if (!masks) | |
438 | return -ENOMEM; | |
439 | memset(masks, 0xff, flen * sizeof(*masks)); | |
440 | ||
441 | for (pc = 0; pc < flen; pc++) { | |
442 | memvalid &= masks[pc]; | |
443 | ||
444 | switch (filter[pc].code) { | |
445 | case BPF_S_ST: | |
446 | case BPF_S_STX: | |
447 | memvalid |= (1 << filter[pc].k); | |
448 | break; | |
449 | case BPF_S_LD_MEM: | |
450 | case BPF_S_LDX_MEM: | |
451 | if (!(memvalid & (1 << filter[pc].k))) { | |
452 | ret = -EINVAL; | |
453 | goto error; | |
454 | } | |
455 | break; | |
456 | case BPF_S_JMP_JA: | |
457 | /* a jump must set masks on target */ | |
458 | masks[pc + 1 + filter[pc].k] &= memvalid; | |
459 | memvalid = ~0; | |
460 | break; | |
461 | case BPF_S_JMP_JEQ_K: | |
462 | case BPF_S_JMP_JEQ_X: | |
463 | case BPF_S_JMP_JGE_K: | |
464 | case BPF_S_JMP_JGE_X: | |
465 | case BPF_S_JMP_JGT_K: | |
466 | case BPF_S_JMP_JGT_X: | |
467 | case BPF_S_JMP_JSET_X: | |
468 | case BPF_S_JMP_JSET_K: | |
469 | /* a jump must set masks on targets */ | |
470 | masks[pc + 1 + filter[pc].jt] &= memvalid; | |
471 | masks[pc + 1 + filter[pc].jf] &= memvalid; | |
472 | memvalid = ~0; | |
473 | break; | |
474 | } | |
475 | } | |
476 | error: | |
477 | kfree(masks); | |
478 | return ret; | |
479 | } | |
480 | ||
1da177e4 LT |
481 | /** |
482 | * sk_chk_filter - verify socket filter code | |
483 | * @filter: filter to verify | |
484 | * @flen: length of filter | |
485 | * | |
486 | * Check the user's filter code. If we let some ugly | |
487 | * filter code slip through kaboom! The filter must contain | |
93699863 KK |
488 | * no references or jumps that are out of range, no illegal |
489 | * instructions, and must end with a RET instruction. | |
1da177e4 | 490 | * |
7b11f69f KK |
491 | * All jumps are forward as they are not signed. |
492 | * | |
493 | * Returns 0 if the rule set is legal or -EINVAL if not. | |
1da177e4 LT |
494 | */ |
495 | int sk_chk_filter(struct sock_filter *filter, int flen) | |
496 | { | |
cba328fc TH |
497 | /* |
498 | * Valid instructions are initialized to non-0. | |
499 | * Invalid instructions are initialized to 0. | |
500 | */ | |
501 | static const u8 codes[] = { | |
8c1592d6 ED |
502 | [BPF_ALU|BPF_ADD|BPF_K] = BPF_S_ALU_ADD_K, |
503 | [BPF_ALU|BPF_ADD|BPF_X] = BPF_S_ALU_ADD_X, | |
504 | [BPF_ALU|BPF_SUB|BPF_K] = BPF_S_ALU_SUB_K, | |
505 | [BPF_ALU|BPF_SUB|BPF_X] = BPF_S_ALU_SUB_X, | |
506 | [BPF_ALU|BPF_MUL|BPF_K] = BPF_S_ALU_MUL_K, | |
507 | [BPF_ALU|BPF_MUL|BPF_X] = BPF_S_ALU_MUL_X, | |
508 | [BPF_ALU|BPF_DIV|BPF_X] = BPF_S_ALU_DIV_X, | |
509 | [BPF_ALU|BPF_AND|BPF_K] = BPF_S_ALU_AND_K, | |
510 | [BPF_ALU|BPF_AND|BPF_X] = BPF_S_ALU_AND_X, | |
511 | [BPF_ALU|BPF_OR|BPF_K] = BPF_S_ALU_OR_K, | |
512 | [BPF_ALU|BPF_OR|BPF_X] = BPF_S_ALU_OR_X, | |
513 | [BPF_ALU|BPF_LSH|BPF_K] = BPF_S_ALU_LSH_K, | |
514 | [BPF_ALU|BPF_LSH|BPF_X] = BPF_S_ALU_LSH_X, | |
515 | [BPF_ALU|BPF_RSH|BPF_K] = BPF_S_ALU_RSH_K, | |
516 | [BPF_ALU|BPF_RSH|BPF_X] = BPF_S_ALU_RSH_X, | |
517 | [BPF_ALU|BPF_NEG] = BPF_S_ALU_NEG, | |
518 | [BPF_LD|BPF_W|BPF_ABS] = BPF_S_LD_W_ABS, | |
519 | [BPF_LD|BPF_H|BPF_ABS] = BPF_S_LD_H_ABS, | |
520 | [BPF_LD|BPF_B|BPF_ABS] = BPF_S_LD_B_ABS, | |
521 | [BPF_LD|BPF_W|BPF_LEN] = BPF_S_LD_W_LEN, | |
522 | [BPF_LD|BPF_W|BPF_IND] = BPF_S_LD_W_IND, | |
523 | [BPF_LD|BPF_H|BPF_IND] = BPF_S_LD_H_IND, | |
524 | [BPF_LD|BPF_B|BPF_IND] = BPF_S_LD_B_IND, | |
525 | [BPF_LD|BPF_IMM] = BPF_S_LD_IMM, | |
526 | [BPF_LDX|BPF_W|BPF_LEN] = BPF_S_LDX_W_LEN, | |
527 | [BPF_LDX|BPF_B|BPF_MSH] = BPF_S_LDX_B_MSH, | |
528 | [BPF_LDX|BPF_IMM] = BPF_S_LDX_IMM, | |
529 | [BPF_MISC|BPF_TAX] = BPF_S_MISC_TAX, | |
530 | [BPF_MISC|BPF_TXA] = BPF_S_MISC_TXA, | |
531 | [BPF_RET|BPF_K] = BPF_S_RET_K, | |
532 | [BPF_RET|BPF_A] = BPF_S_RET_A, | |
533 | [BPF_ALU|BPF_DIV|BPF_K] = BPF_S_ALU_DIV_K, | |
534 | [BPF_LD|BPF_MEM] = BPF_S_LD_MEM, | |
535 | [BPF_LDX|BPF_MEM] = BPF_S_LDX_MEM, | |
536 | [BPF_ST] = BPF_S_ST, | |
537 | [BPF_STX] = BPF_S_STX, | |
538 | [BPF_JMP|BPF_JA] = BPF_S_JMP_JA, | |
539 | [BPF_JMP|BPF_JEQ|BPF_K] = BPF_S_JMP_JEQ_K, | |
540 | [BPF_JMP|BPF_JEQ|BPF_X] = BPF_S_JMP_JEQ_X, | |
541 | [BPF_JMP|BPF_JGE|BPF_K] = BPF_S_JMP_JGE_K, | |
542 | [BPF_JMP|BPF_JGE|BPF_X] = BPF_S_JMP_JGE_X, | |
543 | [BPF_JMP|BPF_JGT|BPF_K] = BPF_S_JMP_JGT_K, | |
544 | [BPF_JMP|BPF_JGT|BPF_X] = BPF_S_JMP_JGT_X, | |
545 | [BPF_JMP|BPF_JSET|BPF_K] = BPF_S_JMP_JSET_K, | |
546 | [BPF_JMP|BPF_JSET|BPF_X] = BPF_S_JMP_JSET_X, | |
cba328fc | 547 | }; |
1da177e4 LT |
548 | int pc; |
549 | ||
1b93ae64 | 550 | if (flen == 0 || flen > BPF_MAXINSNS) |
1da177e4 LT |
551 | return -EINVAL; |
552 | ||
553 | /* check the filter code now */ | |
554 | for (pc = 0; pc < flen; pc++) { | |
cba328fc TH |
555 | struct sock_filter *ftest = &filter[pc]; |
556 | u16 code = ftest->code; | |
93699863 | 557 | |
cba328fc TH |
558 | if (code >= ARRAY_SIZE(codes)) |
559 | return -EINVAL; | |
560 | code = codes[code]; | |
8c1592d6 | 561 | if (!code) |
cba328fc | 562 | return -EINVAL; |
93699863 | 563 | /* Some instructions need special checks */ |
cba328fc TH |
564 | switch (code) { |
565 | case BPF_S_ALU_DIV_K: | |
93699863 KK |
566 | /* check for division by zero */ |
567 | if (ftest->k == 0) | |
1da177e4 | 568 | return -EINVAL; |
c26aed40 | 569 | ftest->k = reciprocal_value(ftest->k); |
93699863 | 570 | break; |
cba328fc TH |
571 | case BPF_S_LD_MEM: |
572 | case BPF_S_LDX_MEM: | |
573 | case BPF_S_ST: | |
574 | case BPF_S_STX: | |
575 | /* check for invalid memory addresses */ | |
93699863 KK |
576 | if (ftest->k >= BPF_MEMWORDS) |
577 | return -EINVAL; | |
578 | break; | |
cba328fc | 579 | case BPF_S_JMP_JA: |
93699863 KK |
580 | /* |
581 | * Note, the large ftest->k might cause loops. | |
582 | * Compare this with conditional jumps below, | |
583 | * where offsets are limited. --ANK (981016) | |
584 | */ | |
585 | if (ftest->k >= (unsigned)(flen-pc-1)) | |
586 | return -EINVAL; | |
01f2f3f6 | 587 | break; |
01f2f3f6 HPP |
588 | case BPF_S_JMP_JEQ_K: |
589 | case BPF_S_JMP_JEQ_X: | |
590 | case BPF_S_JMP_JGE_K: | |
591 | case BPF_S_JMP_JGE_X: | |
592 | case BPF_S_JMP_JGT_K: | |
593 | case BPF_S_JMP_JGT_X: | |
594 | case BPF_S_JMP_JSET_X: | |
595 | case BPF_S_JMP_JSET_K: | |
cba328fc | 596 | /* for conditionals both must be safe */ |
e35bedf3 | 597 | if (pc + ftest->jt + 1 >= flen || |
93699863 KK |
598 | pc + ftest->jf + 1 >= flen) |
599 | return -EINVAL; | |
cba328fc | 600 | break; |
12b16dad ED |
601 | case BPF_S_LD_W_ABS: |
602 | case BPF_S_LD_H_ABS: | |
603 | case BPF_S_LD_B_ABS: | |
604 | #define ANCILLARY(CODE) case SKF_AD_OFF + SKF_AD_##CODE: \ | |
605 | code = BPF_S_ANC_##CODE; \ | |
606 | break | |
607 | switch (ftest->k) { | |
608 | ANCILLARY(PROTOCOL); | |
609 | ANCILLARY(PKTTYPE); | |
610 | ANCILLARY(IFINDEX); | |
611 | ANCILLARY(NLATTR); | |
612 | ANCILLARY(NLATTR_NEST); | |
613 | ANCILLARY(MARK); | |
614 | ANCILLARY(QUEUE); | |
615 | ANCILLARY(HATYPE); | |
616 | ANCILLARY(RXHASH); | |
617 | ANCILLARY(CPU); | |
618 | } | |
01f2f3f6 | 619 | } |
cba328fc | 620 | ftest->code = code; |
01f2f3f6 | 621 | } |
93699863 | 622 | |
01f2f3f6 HPP |
623 | /* last instruction must be a RET code */ |
624 | switch (filter[flen - 1].code) { | |
625 | case BPF_S_RET_K: | |
626 | case BPF_S_RET_A: | |
2d5311e4 | 627 | return check_load_and_stores(filter, flen); |
cba328fc TH |
628 | } |
629 | return -EINVAL; | |
1da177e4 | 630 | } |
b715631f | 631 | EXPORT_SYMBOL(sk_chk_filter); |
1da177e4 | 632 | |
47e958ea | 633 | /** |
46bcf14f | 634 | * sk_filter_release_rcu - Release a socket filter by rcu_head |
47e958ea PE |
635 | * @rcu: rcu_head that contains the sk_filter to free |
636 | */ | |
46bcf14f | 637 | void sk_filter_release_rcu(struct rcu_head *rcu) |
47e958ea PE |
638 | { |
639 | struct sk_filter *fp = container_of(rcu, struct sk_filter, rcu); | |
640 | ||
46bcf14f | 641 | kfree(fp); |
47e958ea | 642 | } |
46bcf14f | 643 | EXPORT_SYMBOL(sk_filter_release_rcu); |
47e958ea | 644 | |
1da177e4 LT |
645 | /** |
646 | * sk_attach_filter - attach a socket filter | |
647 | * @fprog: the filter program | |
648 | * @sk: the socket to use | |
649 | * | |
650 | * Attach the user's filter code. We first run some sanity checks on | |
651 | * it to make sure it does not explode on us later. If an error | |
652 | * occurs or there is insufficient memory for the filter a negative | |
653 | * errno code is returned. On success the return is zero. | |
654 | */ | |
655 | int sk_attach_filter(struct sock_fprog *fprog, struct sock *sk) | |
656 | { | |
d3904b73 | 657 | struct sk_filter *fp, *old_fp; |
1da177e4 LT |
658 | unsigned int fsize = sizeof(struct sock_filter) * fprog->len; |
659 | int err; | |
660 | ||
661 | /* Make sure new filter is there and in the right amounts. */ | |
e35bedf3 KK |
662 | if (fprog->filter == NULL) |
663 | return -EINVAL; | |
1da177e4 LT |
664 | |
665 | fp = sock_kmalloc(sk, fsize+sizeof(*fp), GFP_KERNEL); | |
666 | if (!fp) | |
667 | return -ENOMEM; | |
668 | if (copy_from_user(fp->insns, fprog->filter, fsize)) { | |
4ec93edb | 669 | sock_kfree_s(sk, fp, fsize+sizeof(*fp)); |
1da177e4 LT |
670 | return -EFAULT; |
671 | } | |
672 | ||
673 | atomic_set(&fp->refcnt, 1); | |
674 | fp->len = fprog->len; | |
675 | ||
676 | err = sk_chk_filter(fp->insns, fp->len); | |
d3904b73 PE |
677 | if (err) { |
678 | sk_filter_uncharge(sk, fp); | |
679 | return err; | |
1da177e4 LT |
680 | } |
681 | ||
f91ff5b9 ED |
682 | old_fp = rcu_dereference_protected(sk->sk_filter, |
683 | sock_owned_by_user(sk)); | |
d3904b73 | 684 | rcu_assign_pointer(sk->sk_filter, fp); |
d3904b73 | 685 | |
9b013e05 | 686 | if (old_fp) |
46bcf14f | 687 | sk_filter_uncharge(sk, old_fp); |
d3904b73 | 688 | return 0; |
1da177e4 | 689 | } |
5ff3f073 | 690 | EXPORT_SYMBOL_GPL(sk_attach_filter); |
1da177e4 | 691 | |
55b33325 PE |
692 | int sk_detach_filter(struct sock *sk) |
693 | { | |
694 | int ret = -ENOENT; | |
695 | struct sk_filter *filter; | |
696 | ||
f91ff5b9 ED |
697 | filter = rcu_dereference_protected(sk->sk_filter, |
698 | sock_owned_by_user(sk)); | |
55b33325 PE |
699 | if (filter) { |
700 | rcu_assign_pointer(sk->sk_filter, NULL); | |
46bcf14f | 701 | sk_filter_uncharge(sk, filter); |
55b33325 PE |
702 | ret = 0; |
703 | } | |
55b33325 PE |
704 | return ret; |
705 | } | |
5ff3f073 | 706 | EXPORT_SYMBOL_GPL(sk_detach_filter); |