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Commit | Line | Data |
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1da177e4 LT |
1 | /* |
2 | * Linux Socket Filter - Kernel level socket filtering | |
3 | * | |
bd4cf0ed AS |
4 | * Based on the design of the Berkeley Packet Filter. The new |
5 | * internal format has been designed by PLUMgrid: | |
1da177e4 | 6 | * |
bd4cf0ed AS |
7 | * Copyright (c) 2011 - 2014 PLUMgrid, http://plumgrid.com |
8 | * | |
9 | * Authors: | |
10 | * | |
11 | * Jay Schulist <jschlst@samba.org> | |
12 | * Alexei Starovoitov <ast@plumgrid.com> | |
13 | * Daniel Borkmann <dborkman@redhat.com> | |
1da177e4 LT |
14 | * |
15 | * This program is free software; you can redistribute it and/or | |
16 | * modify it under the terms of the GNU General Public License | |
17 | * as published by the Free Software Foundation; either version | |
18 | * 2 of the License, or (at your option) any later version. | |
19 | * | |
20 | * Andi Kleen - Fix a few bad bugs and races. | |
93699863 | 21 | * Kris Katterjohn - Added many additional checks in sk_chk_filter() |
1da177e4 LT |
22 | */ |
23 | ||
24 | #include <linux/module.h> | |
25 | #include <linux/types.h> | |
1da177e4 LT |
26 | #include <linux/mm.h> |
27 | #include <linux/fcntl.h> | |
28 | #include <linux/socket.h> | |
29 | #include <linux/in.h> | |
30 | #include <linux/inet.h> | |
31 | #include <linux/netdevice.h> | |
32 | #include <linux/if_packet.h> | |
5a0e3ad6 | 33 | #include <linux/gfp.h> |
1da177e4 LT |
34 | #include <net/ip.h> |
35 | #include <net/protocol.h> | |
4738c1db | 36 | #include <net/netlink.h> |
1da177e4 LT |
37 | #include <linux/skbuff.h> |
38 | #include <net/sock.h> | |
39 | #include <linux/errno.h> | |
40 | #include <linux/timer.h> | |
1da177e4 | 41 | #include <asm/uaccess.h> |
40daafc8 | 42 | #include <asm/unaligned.h> |
1da177e4 | 43 | #include <linux/filter.h> |
86e4ca66 | 44 | #include <linux/ratelimit.h> |
46b325c7 | 45 | #include <linux/seccomp.h> |
f3335031 | 46 | #include <linux/if_vlan.h> |
1da177e4 | 47 | |
30743837 | 48 | /* Registers */ |
1268e253 DM |
49 | #define BPF_R0 regs[BPF_REG_0] |
50 | #define BPF_R1 regs[BPF_REG_1] | |
51 | #define BPF_R2 regs[BPF_REG_2] | |
52 | #define BPF_R3 regs[BPF_REG_3] | |
53 | #define BPF_R4 regs[BPF_REG_4] | |
54 | #define BPF_R5 regs[BPF_REG_5] | |
55 | #define BPF_R6 regs[BPF_REG_6] | |
56 | #define BPF_R7 regs[BPF_REG_7] | |
57 | #define BPF_R8 regs[BPF_REG_8] | |
58 | #define BPF_R9 regs[BPF_REG_9] | |
59 | #define BPF_R10 regs[BPF_REG_10] | |
30743837 DB |
60 | |
61 | /* Named registers */ | |
e430f34e AS |
62 | #define DST regs[insn->dst_reg] |
63 | #define SRC regs[insn->src_reg] | |
30743837 DB |
64 | #define FP regs[BPF_REG_FP] |
65 | #define ARG1 regs[BPF_REG_ARG1] | |
66 | #define CTX regs[BPF_REG_CTX] | |
e430f34e | 67 | #define IMM insn->imm |
30743837 | 68 | |
f03fb3f4 JS |
69 | /* No hurry in this branch |
70 | * | |
71 | * Exported for the bpf jit load helper. | |
72 | */ | |
73 | void *bpf_internal_load_pointer_neg_helper(const struct sk_buff *skb, int k, unsigned int size) | |
1da177e4 LT |
74 | { |
75 | u8 *ptr = NULL; | |
76 | ||
77 | if (k >= SKF_NET_OFF) | |
d56f90a7 | 78 | ptr = skb_network_header(skb) + k - SKF_NET_OFF; |
1da177e4 | 79 | else if (k >= SKF_LL_OFF) |
98e399f8 | 80 | ptr = skb_mac_header(skb) + k - SKF_LL_OFF; |
4bc65dd8 | 81 | if (ptr >= skb->head && ptr + size <= skb_tail_pointer(skb)) |
1da177e4 | 82 | return ptr; |
eb9672f4 | 83 | |
1da177e4 LT |
84 | return NULL; |
85 | } | |
86 | ||
62ab0812 | 87 | static inline void *load_pointer(const struct sk_buff *skb, int k, |
4ec93edb | 88 | unsigned int size, void *buffer) |
0b05b2a4 PM |
89 | { |
90 | if (k >= 0) | |
91 | return skb_header_pointer(skb, k, size, buffer); | |
eb9672f4 | 92 | |
f03fb3f4 | 93 | return bpf_internal_load_pointer_neg_helper(skb, k, size); |
0b05b2a4 PM |
94 | } |
95 | ||
43db6d65 SH |
96 | /** |
97 | * sk_filter - run a packet through a socket filter | |
98 | * @sk: sock associated with &sk_buff | |
99 | * @skb: buffer to filter | |
43db6d65 SH |
100 | * |
101 | * Run the filter code and then cut skb->data to correct size returned by | |
102 | * sk_run_filter. If pkt_len is 0 we toss packet. If skb->len is smaller | |
103 | * than pkt_len we keep whole skb->data. This is the socket level | |
104 | * wrapper to sk_run_filter. It returns 0 if the packet should | |
105 | * be accepted or -EPERM if the packet should be tossed. | |
106 | * | |
107 | */ | |
108 | int sk_filter(struct sock *sk, struct sk_buff *skb) | |
109 | { | |
110 | int err; | |
111 | struct sk_filter *filter; | |
112 | ||
c93bdd0e MG |
113 | /* |
114 | * If the skb was allocated from pfmemalloc reserves, only | |
115 | * allow SOCK_MEMALLOC sockets to use it as this socket is | |
116 | * helping free memory | |
117 | */ | |
118 | if (skb_pfmemalloc(skb) && !sock_flag(sk, SOCK_MEMALLOC)) | |
119 | return -ENOMEM; | |
120 | ||
43db6d65 SH |
121 | err = security_sock_rcv_skb(sk, skb); |
122 | if (err) | |
123 | return err; | |
124 | ||
80f8f102 ED |
125 | rcu_read_lock(); |
126 | filter = rcu_dereference(sk->sk_filter); | |
43db6d65 | 127 | if (filter) { |
0a14842f | 128 | unsigned int pkt_len = SK_RUN_FILTER(filter, skb); |
0d7da9dd | 129 | |
43db6d65 SH |
130 | err = pkt_len ? pskb_trim(skb, pkt_len) : -EPERM; |
131 | } | |
80f8f102 | 132 | rcu_read_unlock(); |
43db6d65 SH |
133 | |
134 | return err; | |
135 | } | |
136 | EXPORT_SYMBOL(sk_filter); | |
137 | ||
bd4cf0ed AS |
138 | /* Base function for offset calculation. Needs to go into .text section, |
139 | * therefore keeping it non-static as well; will also be used by JITs | |
140 | * anyway later on, so do not let the compiler omit it. | |
141 | */ | |
142 | noinline u64 __bpf_call_base(u64 r1, u64 r2, u64 r3, u64 r4, u64 r5) | |
143 | { | |
144 | return 0; | |
145 | } | |
146 | ||
1da177e4 | 147 | /** |
bd4cf0ed AS |
148 | * __sk_run_filter - run a filter on a given context |
149 | * @ctx: buffer to run the filter on | |
01d32f6e | 150 | * @insn: filter to apply |
1da177e4 | 151 | * |
bd4cf0ed | 152 | * Decode and apply filter instructions to the skb->data. Return length to |
01d32f6e | 153 | * keep, 0 for none. @ctx is the data we are operating on, @insn is the |
bd4cf0ed | 154 | * array of filter instructions. |
1da177e4 | 155 | */ |
5fe821a9 | 156 | static unsigned int __sk_run_filter(void *ctx, const struct sock_filter_int *insn) |
1da177e4 | 157 | { |
bd4cf0ed AS |
158 | u64 stack[MAX_BPF_STACK / sizeof(u64)]; |
159 | u64 regs[MAX_BPF_REG], tmp; | |
bd4cf0ed AS |
160 | static const void *jumptable[256] = { |
161 | [0 ... 255] = &&default_label, | |
162 | /* Now overwrite non-defaults ... */ | |
8556ce79 DB |
163 | /* 32 bit ALU operations */ |
164 | [BPF_ALU | BPF_ADD | BPF_X] = &&ALU_ADD_X, | |
165 | [BPF_ALU | BPF_ADD | BPF_K] = &&ALU_ADD_K, | |
166 | [BPF_ALU | BPF_SUB | BPF_X] = &&ALU_SUB_X, | |
167 | [BPF_ALU | BPF_SUB | BPF_K] = &&ALU_SUB_K, | |
168 | [BPF_ALU | BPF_AND | BPF_X] = &&ALU_AND_X, | |
169 | [BPF_ALU | BPF_AND | BPF_K] = &&ALU_AND_K, | |
170 | [BPF_ALU | BPF_OR | BPF_X] = &&ALU_OR_X, | |
171 | [BPF_ALU | BPF_OR | BPF_K] = &&ALU_OR_K, | |
172 | [BPF_ALU | BPF_LSH | BPF_X] = &&ALU_LSH_X, | |
173 | [BPF_ALU | BPF_LSH | BPF_K] = &&ALU_LSH_K, | |
174 | [BPF_ALU | BPF_RSH | BPF_X] = &&ALU_RSH_X, | |
175 | [BPF_ALU | BPF_RSH | BPF_K] = &&ALU_RSH_K, | |
176 | [BPF_ALU | BPF_XOR | BPF_X] = &&ALU_XOR_X, | |
177 | [BPF_ALU | BPF_XOR | BPF_K] = &&ALU_XOR_K, | |
178 | [BPF_ALU | BPF_MUL | BPF_X] = &&ALU_MUL_X, | |
179 | [BPF_ALU | BPF_MUL | BPF_K] = &&ALU_MUL_K, | |
180 | [BPF_ALU | BPF_MOV | BPF_X] = &&ALU_MOV_X, | |
181 | [BPF_ALU | BPF_MOV | BPF_K] = &&ALU_MOV_K, | |
182 | [BPF_ALU | BPF_DIV | BPF_X] = &&ALU_DIV_X, | |
183 | [BPF_ALU | BPF_DIV | BPF_K] = &&ALU_DIV_K, | |
184 | [BPF_ALU | BPF_MOD | BPF_X] = &&ALU_MOD_X, | |
185 | [BPF_ALU | BPF_MOD | BPF_K] = &&ALU_MOD_K, | |
186 | [BPF_ALU | BPF_NEG] = &&ALU_NEG, | |
187 | [BPF_ALU | BPF_END | BPF_TO_BE] = &&ALU_END_TO_BE, | |
188 | [BPF_ALU | BPF_END | BPF_TO_LE] = &&ALU_END_TO_LE, | |
189 | /* 64 bit ALU operations */ | |
190 | [BPF_ALU64 | BPF_ADD | BPF_X] = &&ALU64_ADD_X, | |
191 | [BPF_ALU64 | BPF_ADD | BPF_K] = &&ALU64_ADD_K, | |
192 | [BPF_ALU64 | BPF_SUB | BPF_X] = &&ALU64_SUB_X, | |
193 | [BPF_ALU64 | BPF_SUB | BPF_K] = &&ALU64_SUB_K, | |
194 | [BPF_ALU64 | BPF_AND | BPF_X] = &&ALU64_AND_X, | |
195 | [BPF_ALU64 | BPF_AND | BPF_K] = &&ALU64_AND_K, | |
196 | [BPF_ALU64 | BPF_OR | BPF_X] = &&ALU64_OR_X, | |
197 | [BPF_ALU64 | BPF_OR | BPF_K] = &&ALU64_OR_K, | |
198 | [BPF_ALU64 | BPF_LSH | BPF_X] = &&ALU64_LSH_X, | |
199 | [BPF_ALU64 | BPF_LSH | BPF_K] = &&ALU64_LSH_K, | |
200 | [BPF_ALU64 | BPF_RSH | BPF_X] = &&ALU64_RSH_X, | |
201 | [BPF_ALU64 | BPF_RSH | BPF_K] = &&ALU64_RSH_K, | |
202 | [BPF_ALU64 | BPF_XOR | BPF_X] = &&ALU64_XOR_X, | |
203 | [BPF_ALU64 | BPF_XOR | BPF_K] = &&ALU64_XOR_K, | |
204 | [BPF_ALU64 | BPF_MUL | BPF_X] = &&ALU64_MUL_X, | |
205 | [BPF_ALU64 | BPF_MUL | BPF_K] = &&ALU64_MUL_K, | |
206 | [BPF_ALU64 | BPF_MOV | BPF_X] = &&ALU64_MOV_X, | |
207 | [BPF_ALU64 | BPF_MOV | BPF_K] = &&ALU64_MOV_K, | |
208 | [BPF_ALU64 | BPF_ARSH | BPF_X] = &&ALU64_ARSH_X, | |
209 | [BPF_ALU64 | BPF_ARSH | BPF_K] = &&ALU64_ARSH_K, | |
210 | [BPF_ALU64 | BPF_DIV | BPF_X] = &&ALU64_DIV_X, | |
211 | [BPF_ALU64 | BPF_DIV | BPF_K] = &&ALU64_DIV_K, | |
212 | [BPF_ALU64 | BPF_MOD | BPF_X] = &&ALU64_MOD_X, | |
213 | [BPF_ALU64 | BPF_MOD | BPF_K] = &&ALU64_MOD_K, | |
214 | [BPF_ALU64 | BPF_NEG] = &&ALU64_NEG, | |
215 | /* Call instruction */ | |
216 | [BPF_JMP | BPF_CALL] = &&JMP_CALL, | |
217 | /* Jumps */ | |
218 | [BPF_JMP | BPF_JA] = &&JMP_JA, | |
219 | [BPF_JMP | BPF_JEQ | BPF_X] = &&JMP_JEQ_X, | |
220 | [BPF_JMP | BPF_JEQ | BPF_K] = &&JMP_JEQ_K, | |
221 | [BPF_JMP | BPF_JNE | BPF_X] = &&JMP_JNE_X, | |
222 | [BPF_JMP | BPF_JNE | BPF_K] = &&JMP_JNE_K, | |
223 | [BPF_JMP | BPF_JGT | BPF_X] = &&JMP_JGT_X, | |
224 | [BPF_JMP | BPF_JGT | BPF_K] = &&JMP_JGT_K, | |
225 | [BPF_JMP | BPF_JGE | BPF_X] = &&JMP_JGE_X, | |
226 | [BPF_JMP | BPF_JGE | BPF_K] = &&JMP_JGE_K, | |
227 | [BPF_JMP | BPF_JSGT | BPF_X] = &&JMP_JSGT_X, | |
228 | [BPF_JMP | BPF_JSGT | BPF_K] = &&JMP_JSGT_K, | |
229 | [BPF_JMP | BPF_JSGE | BPF_X] = &&JMP_JSGE_X, | |
230 | [BPF_JMP | BPF_JSGE | BPF_K] = &&JMP_JSGE_K, | |
231 | [BPF_JMP | BPF_JSET | BPF_X] = &&JMP_JSET_X, | |
232 | [BPF_JMP | BPF_JSET | BPF_K] = &&JMP_JSET_K, | |
233 | /* Program return */ | |
234 | [BPF_JMP | BPF_EXIT] = &&JMP_EXIT, | |
235 | /* Store instructions */ | |
236 | [BPF_STX | BPF_MEM | BPF_B] = &&STX_MEM_B, | |
237 | [BPF_STX | BPF_MEM | BPF_H] = &&STX_MEM_H, | |
238 | [BPF_STX | BPF_MEM | BPF_W] = &&STX_MEM_W, | |
239 | [BPF_STX | BPF_MEM | BPF_DW] = &&STX_MEM_DW, | |
240 | [BPF_STX | BPF_XADD | BPF_W] = &&STX_XADD_W, | |
241 | [BPF_STX | BPF_XADD | BPF_DW] = &&STX_XADD_DW, | |
242 | [BPF_ST | BPF_MEM | BPF_B] = &&ST_MEM_B, | |
243 | [BPF_ST | BPF_MEM | BPF_H] = &&ST_MEM_H, | |
244 | [BPF_ST | BPF_MEM | BPF_W] = &&ST_MEM_W, | |
245 | [BPF_ST | BPF_MEM | BPF_DW] = &&ST_MEM_DW, | |
246 | /* Load instructions */ | |
247 | [BPF_LDX | BPF_MEM | BPF_B] = &&LDX_MEM_B, | |
248 | [BPF_LDX | BPF_MEM | BPF_H] = &&LDX_MEM_H, | |
249 | [BPF_LDX | BPF_MEM | BPF_W] = &&LDX_MEM_W, | |
250 | [BPF_LDX | BPF_MEM | BPF_DW] = &&LDX_MEM_DW, | |
251 | [BPF_LD | BPF_ABS | BPF_W] = &&LD_ABS_W, | |
252 | [BPF_LD | BPF_ABS | BPF_H] = &&LD_ABS_H, | |
253 | [BPF_LD | BPF_ABS | BPF_B] = &&LD_ABS_B, | |
254 | [BPF_LD | BPF_IND | BPF_W] = &&LD_IND_W, | |
255 | [BPF_LD | BPF_IND | BPF_H] = &&LD_IND_H, | |
256 | [BPF_LD | BPF_IND | BPF_B] = &&LD_IND_B, | |
bd4cf0ed | 257 | }; |
30743837 DB |
258 | void *ptr; |
259 | int off; | |
1da177e4 | 260 | |
30743837 DB |
261 | #define CONT ({ insn++; goto select_insn; }) |
262 | #define CONT_JMP ({ insn++; goto select_insn; }) | |
263 | ||
264 | FP = (u64) (unsigned long) &stack[ARRAY_SIZE(stack)]; | |
265 | ARG1 = (u64) (unsigned long) ctx; | |
266 | ||
e430f34e | 267 | /* Registers used in classic BPF programs need to be reset first. */ |
30743837 DB |
268 | regs[BPF_REG_A] = 0; |
269 | regs[BPF_REG_X] = 0; | |
bd4cf0ed AS |
270 | |
271 | select_insn: | |
272 | goto *jumptable[insn->code]; | |
273 | ||
274 | /* ALU */ | |
275 | #define ALU(OPCODE, OP) \ | |
5bcfedf0 | 276 | ALU64_##OPCODE##_X: \ |
e430f34e | 277 | DST = DST OP SRC; \ |
bd4cf0ed | 278 | CONT; \ |
5bcfedf0 | 279 | ALU_##OPCODE##_X: \ |
e430f34e | 280 | DST = (u32) DST OP (u32) SRC; \ |
bd4cf0ed | 281 | CONT; \ |
5bcfedf0 | 282 | ALU64_##OPCODE##_K: \ |
e430f34e | 283 | DST = DST OP IMM; \ |
bd4cf0ed | 284 | CONT; \ |
5bcfedf0 | 285 | ALU_##OPCODE##_K: \ |
e430f34e | 286 | DST = (u32) DST OP (u32) IMM; \ |
bd4cf0ed AS |
287 | CONT; |
288 | ||
5bcfedf0 DB |
289 | ALU(ADD, +) |
290 | ALU(SUB, -) | |
291 | ALU(AND, &) | |
292 | ALU(OR, |) | |
293 | ALU(LSH, <<) | |
294 | ALU(RSH, >>) | |
295 | ALU(XOR, ^) | |
296 | ALU(MUL, *) | |
bd4cf0ed | 297 | #undef ALU |
8556ce79 | 298 | ALU_NEG: |
e430f34e | 299 | DST = (u32) -DST; |
bd4cf0ed | 300 | CONT; |
8556ce79 | 301 | ALU64_NEG: |
e430f34e | 302 | DST = -DST; |
bd4cf0ed | 303 | CONT; |
5bcfedf0 | 304 | ALU_MOV_X: |
e430f34e | 305 | DST = (u32) SRC; |
bd4cf0ed | 306 | CONT; |
5bcfedf0 | 307 | ALU_MOV_K: |
e430f34e | 308 | DST = (u32) IMM; |
bd4cf0ed | 309 | CONT; |
5bcfedf0 | 310 | ALU64_MOV_X: |
e430f34e | 311 | DST = SRC; |
bd4cf0ed | 312 | CONT; |
5bcfedf0 | 313 | ALU64_MOV_K: |
e430f34e | 314 | DST = IMM; |
bd4cf0ed | 315 | CONT; |
5bcfedf0 | 316 | ALU64_ARSH_X: |
e430f34e | 317 | (*(s64 *) &DST) >>= SRC; |
bd4cf0ed | 318 | CONT; |
5bcfedf0 | 319 | ALU64_ARSH_K: |
e430f34e | 320 | (*(s64 *) &DST) >>= IMM; |
bd4cf0ed | 321 | CONT; |
5bcfedf0 | 322 | ALU64_MOD_X: |
e430f34e | 323 | if (unlikely(SRC == 0)) |
5f9fde5f | 324 | return 0; |
e430f34e AS |
325 | tmp = DST; |
326 | DST = do_div(tmp, SRC); | |
bd4cf0ed | 327 | CONT; |
5bcfedf0 | 328 | ALU_MOD_X: |
e430f34e | 329 | if (unlikely(SRC == 0)) |
5f9fde5f | 330 | return 0; |
e430f34e AS |
331 | tmp = (u32) DST; |
332 | DST = do_div(tmp, (u32) SRC); | |
bd4cf0ed | 333 | CONT; |
5bcfedf0 | 334 | ALU64_MOD_K: |
e430f34e AS |
335 | tmp = DST; |
336 | DST = do_div(tmp, IMM); | |
bd4cf0ed | 337 | CONT; |
5bcfedf0 | 338 | ALU_MOD_K: |
e430f34e AS |
339 | tmp = (u32) DST; |
340 | DST = do_div(tmp, (u32) IMM); | |
bd4cf0ed | 341 | CONT; |
5bcfedf0 | 342 | ALU64_DIV_X: |
e430f34e | 343 | if (unlikely(SRC == 0)) |
5f9fde5f | 344 | return 0; |
e430f34e | 345 | do_div(DST, SRC); |
bd4cf0ed | 346 | CONT; |
5bcfedf0 | 347 | ALU_DIV_X: |
e430f34e | 348 | if (unlikely(SRC == 0)) |
5f9fde5f | 349 | return 0; |
e430f34e AS |
350 | tmp = (u32) DST; |
351 | do_div(tmp, (u32) SRC); | |
352 | DST = (u32) tmp; | |
bd4cf0ed | 353 | CONT; |
5bcfedf0 | 354 | ALU64_DIV_K: |
e430f34e | 355 | do_div(DST, IMM); |
bd4cf0ed | 356 | CONT; |
5bcfedf0 | 357 | ALU_DIV_K: |
e430f34e AS |
358 | tmp = (u32) DST; |
359 | do_div(tmp, (u32) IMM); | |
360 | DST = (u32) tmp; | |
bd4cf0ed | 361 | CONT; |
5bcfedf0 | 362 | ALU_END_TO_BE: |
e430f34e | 363 | switch (IMM) { |
bd4cf0ed | 364 | case 16: |
e430f34e | 365 | DST = (__force u16) cpu_to_be16(DST); |
bd4cf0ed AS |
366 | break; |
367 | case 32: | |
e430f34e | 368 | DST = (__force u32) cpu_to_be32(DST); |
bd4cf0ed AS |
369 | break; |
370 | case 64: | |
e430f34e | 371 | DST = (__force u64) cpu_to_be64(DST); |
bd4cf0ed AS |
372 | break; |
373 | } | |
374 | CONT; | |
5bcfedf0 | 375 | ALU_END_TO_LE: |
e430f34e | 376 | switch (IMM) { |
bd4cf0ed | 377 | case 16: |
e430f34e | 378 | DST = (__force u16) cpu_to_le16(DST); |
bd4cf0ed AS |
379 | break; |
380 | case 32: | |
e430f34e | 381 | DST = (__force u32) cpu_to_le32(DST); |
bd4cf0ed AS |
382 | break; |
383 | case 64: | |
e430f34e | 384 | DST = (__force u64) cpu_to_le64(DST); |
bd4cf0ed AS |
385 | break; |
386 | } | |
387 | CONT; | |
388 | ||
389 | /* CALL */ | |
8556ce79 | 390 | JMP_CALL: |
1268e253 DM |
391 | /* Function call scratches BPF_R1-BPF_R5 registers, |
392 | * preserves BPF_R6-BPF_R9, and stores return value | |
393 | * into BPF_R0. | |
bd4cf0ed | 394 | */ |
1268e253 DM |
395 | BPF_R0 = (__bpf_call_base + insn->imm)(BPF_R1, BPF_R2, BPF_R3, |
396 | BPF_R4, BPF_R5); | |
bd4cf0ed AS |
397 | CONT; |
398 | ||
399 | /* JMP */ | |
8556ce79 | 400 | JMP_JA: |
bd4cf0ed AS |
401 | insn += insn->off; |
402 | CONT; | |
5bcfedf0 | 403 | JMP_JEQ_X: |
e430f34e | 404 | if (DST == SRC) { |
bd4cf0ed AS |
405 | insn += insn->off; |
406 | CONT_JMP; | |
407 | } | |
408 | CONT; | |
5bcfedf0 | 409 | JMP_JEQ_K: |
e430f34e | 410 | if (DST == IMM) { |
bd4cf0ed AS |
411 | insn += insn->off; |
412 | CONT_JMP; | |
413 | } | |
414 | CONT; | |
5bcfedf0 | 415 | JMP_JNE_X: |
e430f34e | 416 | if (DST != SRC) { |
bd4cf0ed AS |
417 | insn += insn->off; |
418 | CONT_JMP; | |
419 | } | |
420 | CONT; | |
5bcfedf0 | 421 | JMP_JNE_K: |
e430f34e | 422 | if (DST != IMM) { |
bd4cf0ed AS |
423 | insn += insn->off; |
424 | CONT_JMP; | |
425 | } | |
426 | CONT; | |
5bcfedf0 | 427 | JMP_JGT_X: |
e430f34e | 428 | if (DST > SRC) { |
bd4cf0ed AS |
429 | insn += insn->off; |
430 | CONT_JMP; | |
431 | } | |
432 | CONT; | |
5bcfedf0 | 433 | JMP_JGT_K: |
e430f34e | 434 | if (DST > IMM) { |
bd4cf0ed AS |
435 | insn += insn->off; |
436 | CONT_JMP; | |
437 | } | |
438 | CONT; | |
5bcfedf0 | 439 | JMP_JGE_X: |
e430f34e | 440 | if (DST >= SRC) { |
bd4cf0ed AS |
441 | insn += insn->off; |
442 | CONT_JMP; | |
443 | } | |
444 | CONT; | |
5bcfedf0 | 445 | JMP_JGE_K: |
e430f34e | 446 | if (DST >= IMM) { |
bd4cf0ed AS |
447 | insn += insn->off; |
448 | CONT_JMP; | |
449 | } | |
450 | CONT; | |
5bcfedf0 | 451 | JMP_JSGT_X: |
e430f34e | 452 | if (((s64) DST) > ((s64) SRC)) { |
bd4cf0ed AS |
453 | insn += insn->off; |
454 | CONT_JMP; | |
455 | } | |
456 | CONT; | |
5bcfedf0 | 457 | JMP_JSGT_K: |
e430f34e | 458 | if (((s64) DST) > ((s64) IMM)) { |
bd4cf0ed AS |
459 | insn += insn->off; |
460 | CONT_JMP; | |
461 | } | |
462 | CONT; | |
5bcfedf0 | 463 | JMP_JSGE_X: |
e430f34e | 464 | if (((s64) DST) >= ((s64) SRC)) { |
bd4cf0ed AS |
465 | insn += insn->off; |
466 | CONT_JMP; | |
467 | } | |
468 | CONT; | |
5bcfedf0 | 469 | JMP_JSGE_K: |
e430f34e | 470 | if (((s64) DST) >= ((s64) IMM)) { |
bd4cf0ed AS |
471 | insn += insn->off; |
472 | CONT_JMP; | |
473 | } | |
474 | CONT; | |
5bcfedf0 | 475 | JMP_JSET_X: |
e430f34e | 476 | if (DST & SRC) { |
bd4cf0ed AS |
477 | insn += insn->off; |
478 | CONT_JMP; | |
479 | } | |
480 | CONT; | |
5bcfedf0 | 481 | JMP_JSET_K: |
e430f34e | 482 | if (DST & IMM) { |
bd4cf0ed AS |
483 | insn += insn->off; |
484 | CONT_JMP; | |
485 | } | |
486 | CONT; | |
8556ce79 | 487 | JMP_EXIT: |
1268e253 | 488 | return BPF_R0; |
bd4cf0ed AS |
489 | |
490 | /* STX and ST and LDX*/ | |
e430f34e AS |
491 | #define LDST(SIZEOP, SIZE) \ |
492 | STX_MEM_##SIZEOP: \ | |
493 | *(SIZE *)(unsigned long) (DST + insn->off) = SRC; \ | |
494 | CONT; \ | |
495 | ST_MEM_##SIZEOP: \ | |
496 | *(SIZE *)(unsigned long) (DST + insn->off) = IMM; \ | |
497 | CONT; \ | |
498 | LDX_MEM_##SIZEOP: \ | |
499 | DST = *(SIZE *)(unsigned long) (SRC + insn->off); \ | |
bd4cf0ed AS |
500 | CONT; |
501 | ||
5bcfedf0 DB |
502 | LDST(B, u8) |
503 | LDST(H, u16) | |
504 | LDST(W, u32) | |
505 | LDST(DW, u64) | |
bd4cf0ed | 506 | #undef LDST |
e430f34e AS |
507 | STX_XADD_W: /* lock xadd *(u32 *)(dst_reg + off16) += src_reg */ |
508 | atomic_add((u32) SRC, (atomic_t *)(unsigned long) | |
509 | (DST + insn->off)); | |
bd4cf0ed | 510 | CONT; |
e430f34e AS |
511 | STX_XADD_DW: /* lock xadd *(u64 *)(dst_reg + off16) += src_reg */ |
512 | atomic64_add((u64) SRC, (atomic64_t *)(unsigned long) | |
513 | (DST + insn->off)); | |
bd4cf0ed | 514 | CONT; |
e430f34e AS |
515 | LD_ABS_W: /* BPF_R0 = ntohl(*(u32 *) (skb->data + imm32)) */ |
516 | off = IMM; | |
bd4cf0ed | 517 | load_word: |
1268e253 DM |
518 | /* BPF_LD + BPD_ABS and BPF_LD + BPF_IND insns are |
519 | * only appearing in the programs where ctx == | |
520 | * skb. All programs keep 'ctx' in regs[BPF_REG_CTX] | |
521 | * == BPF_R6, sk_convert_filter() saves it in BPF_R6, | |
522 | * internal BPF verifier will check that BPF_R6 == | |
523 | * ctx. | |
bd4cf0ed | 524 | * |
1268e253 DM |
525 | * BPF_ABS and BPF_IND are wrappers of function calls, |
526 | * so they scratch BPF_R1-BPF_R5 registers, preserve | |
527 | * BPF_R6-BPF_R9, and store return value into BPF_R0. | |
bd4cf0ed AS |
528 | * |
529 | * Implicit input: | |
e430f34e | 530 | * ctx == skb == BPF_R6 == CTX |
bd4cf0ed AS |
531 | * |
532 | * Explicit input: | |
e430f34e AS |
533 | * SRC == any register |
534 | * IMM == 32-bit immediate | |
bd4cf0ed AS |
535 | * |
536 | * Output: | |
1268e253 | 537 | * BPF_R0 - 8/16/32-bit skb data converted to cpu endianness |
bd4cf0ed | 538 | */ |
34805931 | 539 | |
61f83d0d | 540 | ptr = load_pointer((struct sk_buff *) (unsigned long) CTX, off, 4, &tmp); |
bd4cf0ed | 541 | if (likely(ptr != NULL)) { |
1268e253 | 542 | BPF_R0 = get_unaligned_be32(ptr); |
bd4cf0ed AS |
543 | CONT; |
544 | } | |
34805931 | 545 | |
bd4cf0ed | 546 | return 0; |
e430f34e AS |
547 | LD_ABS_H: /* BPF_R0 = ntohs(*(u16 *) (skb->data + imm32)) */ |
548 | off = IMM; | |
bd4cf0ed | 549 | load_half: |
61f83d0d | 550 | ptr = load_pointer((struct sk_buff *) (unsigned long) CTX, off, 2, &tmp); |
bd4cf0ed | 551 | if (likely(ptr != NULL)) { |
1268e253 | 552 | BPF_R0 = get_unaligned_be16(ptr); |
bd4cf0ed AS |
553 | CONT; |
554 | } | |
34805931 | 555 | |
bd4cf0ed | 556 | return 0; |
e430f34e AS |
557 | LD_ABS_B: /* BPF_R0 = *(u8 *) (skb->data + imm32) */ |
558 | off = IMM; | |
bd4cf0ed | 559 | load_byte: |
61f83d0d | 560 | ptr = load_pointer((struct sk_buff *) (unsigned long) CTX, off, 1, &tmp); |
bd4cf0ed | 561 | if (likely(ptr != NULL)) { |
1268e253 | 562 | BPF_R0 = *(u8 *)ptr; |
bd4cf0ed AS |
563 | CONT; |
564 | } | |
34805931 | 565 | |
bd4cf0ed | 566 | return 0; |
e430f34e AS |
567 | LD_IND_W: /* BPF_R0 = ntohl(*(u32 *) (skb->data + src_reg + imm32)) */ |
568 | off = IMM + SRC; | |
bd4cf0ed | 569 | goto load_word; |
e430f34e AS |
570 | LD_IND_H: /* BPF_R0 = ntohs(*(u16 *) (skb->data + src_reg + imm32)) */ |
571 | off = IMM + SRC; | |
bd4cf0ed | 572 | goto load_half; |
e430f34e AS |
573 | LD_IND_B: /* BPF_R0 = *(u8 *) (skb->data + src_reg + imm32) */ |
574 | off = IMM + SRC; | |
bd4cf0ed AS |
575 | goto load_byte; |
576 | ||
577 | default_label: | |
578 | /* If we ever reach this, we have a bug somewhere. */ | |
579 | WARN_RATELIMIT(1, "unknown opcode %02x\n", insn->code); | |
580 | return 0; | |
bd4cf0ed AS |
581 | } |
582 | ||
bd4cf0ed AS |
583 | /* Helper to find the offset of pkt_type in sk_buff structure. We want |
584 | * to make sure its still a 3bit field starting at a byte boundary; | |
585 | * taken from arch/x86/net/bpf_jit_comp.c. | |
586 | */ | |
0dcceabb AS |
587 | #ifdef __BIG_ENDIAN_BITFIELD |
588 | #define PKT_TYPE_MAX (7 << 5) | |
589 | #else | |
bd4cf0ed | 590 | #define PKT_TYPE_MAX 7 |
0dcceabb | 591 | #endif |
bd4cf0ed AS |
592 | static unsigned int pkt_type_offset(void) |
593 | { | |
594 | struct sk_buff skb_probe = { .pkt_type = ~0, }; | |
595 | u8 *ct = (u8 *) &skb_probe; | |
596 | unsigned int off; | |
597 | ||
598 | for (off = 0; off < sizeof(struct sk_buff); off++) { | |
599 | if (ct[off] == PKT_TYPE_MAX) | |
600 | return off; | |
601 | } | |
602 | ||
603 | pr_err_once("Please fix %s, as pkt_type couldn't be found!\n", __func__); | |
604 | return -1; | |
605 | } | |
606 | ||
30743837 | 607 | static u64 __skb_get_pay_offset(u64 ctx, u64 a, u64 x, u64 r4, u64 r5) |
bd4cf0ed | 608 | { |
eb9672f4 | 609 | return __skb_get_poff((struct sk_buff *)(unsigned long) ctx); |
bd4cf0ed AS |
610 | } |
611 | ||
30743837 | 612 | static u64 __skb_get_nlattr(u64 ctx, u64 a, u64 x, u64 r4, u64 r5) |
bd4cf0ed | 613 | { |
eb9672f4 | 614 | struct sk_buff *skb = (struct sk_buff *)(unsigned long) ctx; |
bd4cf0ed AS |
615 | struct nlattr *nla; |
616 | ||
617 | if (skb_is_nonlinear(skb)) | |
618 | return 0; | |
619 | ||
05ab8f26 MK |
620 | if (skb->len < sizeof(struct nlattr)) |
621 | return 0; | |
622 | ||
30743837 | 623 | if (a > skb->len - sizeof(struct nlattr)) |
bd4cf0ed AS |
624 | return 0; |
625 | ||
30743837 | 626 | nla = nla_find((struct nlattr *) &skb->data[a], skb->len - a, x); |
bd4cf0ed AS |
627 | if (nla) |
628 | return (void *) nla - (void *) skb->data; | |
629 | ||
630 | return 0; | |
631 | } | |
632 | ||
30743837 | 633 | static u64 __skb_get_nlattr_nest(u64 ctx, u64 a, u64 x, u64 r4, u64 r5) |
bd4cf0ed | 634 | { |
eb9672f4 | 635 | struct sk_buff *skb = (struct sk_buff *)(unsigned long) ctx; |
bd4cf0ed AS |
636 | struct nlattr *nla; |
637 | ||
638 | if (skb_is_nonlinear(skb)) | |
639 | return 0; | |
640 | ||
05ab8f26 MK |
641 | if (skb->len < sizeof(struct nlattr)) |
642 | return 0; | |
643 | ||
30743837 | 644 | if (a > skb->len - sizeof(struct nlattr)) |
bd4cf0ed AS |
645 | return 0; |
646 | ||
30743837 DB |
647 | nla = (struct nlattr *) &skb->data[a]; |
648 | if (nla->nla_len > skb->len - a) | |
bd4cf0ed AS |
649 | return 0; |
650 | ||
30743837 | 651 | nla = nla_find_nested(nla, x); |
bd4cf0ed AS |
652 | if (nla) |
653 | return (void *) nla - (void *) skb->data; | |
654 | ||
655 | return 0; | |
656 | } | |
657 | ||
30743837 | 658 | static u64 __get_raw_cpu_id(u64 ctx, u64 a, u64 x, u64 r4, u64 r5) |
bd4cf0ed AS |
659 | { |
660 | return raw_smp_processor_id(); | |
661 | } | |
662 | ||
4cd3675e | 663 | /* note that this only generates 32-bit random numbers */ |
30743837 | 664 | static u64 __get_random_u32(u64 ctx, u64 a, u64 x, u64 r4, u64 r5) |
4cd3675e | 665 | { |
eb9672f4 | 666 | return prandom_u32(); |
4cd3675e CG |
667 | } |
668 | ||
bd4cf0ed AS |
669 | static bool convert_bpf_extensions(struct sock_filter *fp, |
670 | struct sock_filter_int **insnp) | |
671 | { | |
672 | struct sock_filter_int *insn = *insnp; | |
673 | ||
674 | switch (fp->k) { | |
675 | case SKF_AD_OFF + SKF_AD_PROTOCOL: | |
676 | BUILD_BUG_ON(FIELD_SIZEOF(struct sk_buff, protocol) != 2); | |
677 | ||
e430f34e | 678 | /* A = *(u16 *) (CTX + offsetof(protocol)) */ |
f8f6d679 DB |
679 | *insn++ = BPF_LDX_MEM(BPF_H, BPF_REG_A, BPF_REG_CTX, |
680 | offsetof(struct sk_buff, protocol)); | |
bd4cf0ed | 681 | /* A = ntohs(A) [emitting a nop or swap16] */ |
f8f6d679 | 682 | *insn = BPF_ENDIAN(BPF_FROM_BE, BPF_REG_A, 16); |
bd4cf0ed AS |
683 | break; |
684 | ||
685 | case SKF_AD_OFF + SKF_AD_PKTTYPE: | |
9739eef1 AS |
686 | *insn = BPF_LDX_MEM(BPF_B, BPF_REG_A, BPF_REG_CTX, |
687 | pkt_type_offset()); | |
bd4cf0ed AS |
688 | if (insn->off < 0) |
689 | return false; | |
690 | insn++; | |
9739eef1 | 691 | *insn = BPF_ALU32_IMM(BPF_AND, BPF_REG_A, PKT_TYPE_MAX); |
0dcceabb AS |
692 | #ifdef __BIG_ENDIAN_BITFIELD |
693 | insn++; | |
f666f87b | 694 | *insn = BPF_ALU32_IMM(BPF_RSH, BPF_REG_A, 5); |
0dcceabb | 695 | #endif |
bd4cf0ed AS |
696 | break; |
697 | ||
698 | case SKF_AD_OFF + SKF_AD_IFINDEX: | |
699 | case SKF_AD_OFF + SKF_AD_HATYPE: | |
bd4cf0ed AS |
700 | BUILD_BUG_ON(FIELD_SIZEOF(struct net_device, ifindex) != 4); |
701 | BUILD_BUG_ON(FIELD_SIZEOF(struct net_device, type) != 2); | |
f8f6d679 DB |
702 | BUILD_BUG_ON(bytes_to_bpf_size(FIELD_SIZEOF(struct sk_buff, dev)) < 0); |
703 | ||
704 | *insn++ = BPF_LDX_MEM(bytes_to_bpf_size(FIELD_SIZEOF(struct sk_buff, dev)), | |
705 | BPF_REG_TMP, BPF_REG_CTX, | |
706 | offsetof(struct sk_buff, dev)); | |
707 | /* if (tmp != 0) goto pc + 1 */ | |
708 | *insn++ = BPF_JMP_IMM(BPF_JNE, BPF_REG_TMP, 0, 1); | |
709 | *insn++ = BPF_EXIT_INSN(); | |
710 | if (fp->k == SKF_AD_OFF + SKF_AD_IFINDEX) | |
711 | *insn = BPF_LDX_MEM(BPF_W, BPF_REG_A, BPF_REG_TMP, | |
712 | offsetof(struct net_device, ifindex)); | |
713 | else | |
714 | *insn = BPF_LDX_MEM(BPF_H, BPF_REG_A, BPF_REG_TMP, | |
715 | offsetof(struct net_device, type)); | |
bd4cf0ed AS |
716 | break; |
717 | ||
718 | case SKF_AD_OFF + SKF_AD_MARK: | |
719 | BUILD_BUG_ON(FIELD_SIZEOF(struct sk_buff, mark) != 4); | |
720 | ||
9739eef1 AS |
721 | *insn = BPF_LDX_MEM(BPF_W, BPF_REG_A, BPF_REG_CTX, |
722 | offsetof(struct sk_buff, mark)); | |
bd4cf0ed AS |
723 | break; |
724 | ||
725 | case SKF_AD_OFF + SKF_AD_RXHASH: | |
726 | BUILD_BUG_ON(FIELD_SIZEOF(struct sk_buff, hash) != 4); | |
727 | ||
9739eef1 AS |
728 | *insn = BPF_LDX_MEM(BPF_W, BPF_REG_A, BPF_REG_CTX, |
729 | offsetof(struct sk_buff, hash)); | |
bd4cf0ed AS |
730 | break; |
731 | ||
732 | case SKF_AD_OFF + SKF_AD_QUEUE: | |
733 | BUILD_BUG_ON(FIELD_SIZEOF(struct sk_buff, queue_mapping) != 2); | |
734 | ||
9739eef1 AS |
735 | *insn = BPF_LDX_MEM(BPF_H, BPF_REG_A, BPF_REG_CTX, |
736 | offsetof(struct sk_buff, queue_mapping)); | |
bd4cf0ed AS |
737 | break; |
738 | ||
739 | case SKF_AD_OFF + SKF_AD_VLAN_TAG: | |
740 | case SKF_AD_OFF + SKF_AD_VLAN_TAG_PRESENT: | |
741 | BUILD_BUG_ON(FIELD_SIZEOF(struct sk_buff, vlan_tci) != 2); | |
bd4cf0ed AS |
742 | BUILD_BUG_ON(VLAN_TAG_PRESENT != 0x1000); |
743 | ||
e430f34e | 744 | /* A = *(u16 *) (CTX + offsetof(vlan_tci)) */ |
f8f6d679 DB |
745 | *insn++ = BPF_LDX_MEM(BPF_H, BPF_REG_A, BPF_REG_CTX, |
746 | offsetof(struct sk_buff, vlan_tci)); | |
bd4cf0ed | 747 | if (fp->k == SKF_AD_OFF + SKF_AD_VLAN_TAG) { |
9739eef1 AS |
748 | *insn = BPF_ALU32_IMM(BPF_AND, BPF_REG_A, |
749 | ~VLAN_TAG_PRESENT); | |
bd4cf0ed | 750 | } else { |
9739eef1 | 751 | /* A >>= 12 */ |
f8f6d679 | 752 | *insn++ = BPF_ALU32_IMM(BPF_RSH, BPF_REG_A, 12); |
9739eef1 AS |
753 | /* A &= 1 */ |
754 | *insn = BPF_ALU32_IMM(BPF_AND, BPF_REG_A, 1); | |
bd4cf0ed AS |
755 | } |
756 | break; | |
757 | ||
758 | case SKF_AD_OFF + SKF_AD_PAY_OFFSET: | |
759 | case SKF_AD_OFF + SKF_AD_NLATTR: | |
760 | case SKF_AD_OFF + SKF_AD_NLATTR_NEST: | |
761 | case SKF_AD_OFF + SKF_AD_CPU: | |
4cd3675e | 762 | case SKF_AD_OFF + SKF_AD_RANDOM: |
e430f34e | 763 | /* arg1 = CTX */ |
f8f6d679 | 764 | *insn++ = BPF_MOV64_REG(BPF_REG_ARG1, BPF_REG_CTX); |
bd4cf0ed | 765 | /* arg2 = A */ |
f8f6d679 | 766 | *insn++ = BPF_MOV64_REG(BPF_REG_ARG2, BPF_REG_A); |
bd4cf0ed | 767 | /* arg3 = X */ |
f8f6d679 | 768 | *insn++ = BPF_MOV64_REG(BPF_REG_ARG3, BPF_REG_X); |
e430f34e | 769 | /* Emit call(arg1=CTX, arg2=A, arg3=X) */ |
bd4cf0ed AS |
770 | switch (fp->k) { |
771 | case SKF_AD_OFF + SKF_AD_PAY_OFFSET: | |
f8f6d679 | 772 | *insn = BPF_EMIT_CALL(__skb_get_pay_offset); |
bd4cf0ed AS |
773 | break; |
774 | case SKF_AD_OFF + SKF_AD_NLATTR: | |
f8f6d679 | 775 | *insn = BPF_EMIT_CALL(__skb_get_nlattr); |
bd4cf0ed AS |
776 | break; |
777 | case SKF_AD_OFF + SKF_AD_NLATTR_NEST: | |
f8f6d679 | 778 | *insn = BPF_EMIT_CALL(__skb_get_nlattr_nest); |
bd4cf0ed AS |
779 | break; |
780 | case SKF_AD_OFF + SKF_AD_CPU: | |
f8f6d679 | 781 | *insn = BPF_EMIT_CALL(__get_raw_cpu_id); |
bd4cf0ed | 782 | break; |
4cd3675e | 783 | case SKF_AD_OFF + SKF_AD_RANDOM: |
f8f6d679 | 784 | *insn = BPF_EMIT_CALL(__get_random_u32); |
4cd3675e | 785 | break; |
bd4cf0ed AS |
786 | } |
787 | break; | |
788 | ||
789 | case SKF_AD_OFF + SKF_AD_ALU_XOR_X: | |
9739eef1 AS |
790 | /* A ^= X */ |
791 | *insn = BPF_ALU32_REG(BPF_XOR, BPF_REG_A, BPF_REG_X); | |
bd4cf0ed AS |
792 | break; |
793 | ||
794 | default: | |
795 | /* This is just a dummy call to avoid letting the compiler | |
796 | * evict __bpf_call_base() as an optimization. Placed here | |
797 | * where no-one bothers. | |
798 | */ | |
799 | BUG_ON(__bpf_call_base(0, 0, 0, 0, 0) != 0); | |
800 | return false; | |
801 | } | |
802 | ||
803 | *insnp = insn; | |
804 | return true; | |
805 | } | |
806 | ||
807 | /** | |
808 | * sk_convert_filter - convert filter program | |
809 | * @prog: the user passed filter program | |
810 | * @len: the length of the user passed filter program | |
811 | * @new_prog: buffer where converted program will be stored | |
812 | * @new_len: pointer to store length of converted program | |
813 | * | |
814 | * Remap 'sock_filter' style BPF instruction set to 'sock_filter_ext' style. | |
815 | * Conversion workflow: | |
816 | * | |
817 | * 1) First pass for calculating the new program length: | |
818 | * sk_convert_filter(old_prog, old_len, NULL, &new_len) | |
819 | * | |
820 | * 2) 2nd pass to remap in two passes: 1st pass finds new | |
821 | * jump offsets, 2nd pass remapping: | |
822 | * new_prog = kmalloc(sizeof(struct sock_filter_int) * new_len); | |
823 | * sk_convert_filter(old_prog, old_len, new_prog, &new_len); | |
824 | * | |
825 | * User BPF's register A is mapped to our BPF register 6, user BPF | |
826 | * register X is mapped to BPF register 7; frame pointer is always | |
827 | * register 10; Context 'void *ctx' is stored in register 1, that is, | |
828 | * for socket filters: ctx == 'struct sk_buff *', for seccomp: | |
829 | * ctx == 'struct seccomp_data *'. | |
830 | */ | |
831 | int sk_convert_filter(struct sock_filter *prog, int len, | |
832 | struct sock_filter_int *new_prog, int *new_len) | |
833 | { | |
834 | int new_flen = 0, pass = 0, target, i; | |
835 | struct sock_filter_int *new_insn; | |
836 | struct sock_filter *fp; | |
837 | int *addrs = NULL; | |
838 | u8 bpf_src; | |
839 | ||
840 | BUILD_BUG_ON(BPF_MEMWORDS * sizeof(u32) > MAX_BPF_STACK); | |
30743837 | 841 | BUILD_BUG_ON(BPF_REG_FP + 1 != MAX_BPF_REG); |
bd4cf0ed | 842 | |
6f9a093b | 843 | if (len <= 0 || len > BPF_MAXINSNS) |
bd4cf0ed AS |
844 | return -EINVAL; |
845 | ||
846 | if (new_prog) { | |
847 | addrs = kzalloc(len * sizeof(*addrs), GFP_KERNEL); | |
848 | if (!addrs) | |
849 | return -ENOMEM; | |
850 | } | |
851 | ||
852 | do_pass: | |
853 | new_insn = new_prog; | |
854 | fp = prog; | |
855 | ||
f8f6d679 DB |
856 | if (new_insn) |
857 | *new_insn = BPF_MOV64_REG(BPF_REG_CTX, BPF_REG_ARG1); | |
bd4cf0ed AS |
858 | new_insn++; |
859 | ||
860 | for (i = 0; i < len; fp++, i++) { | |
861 | struct sock_filter_int tmp_insns[6] = { }; | |
862 | struct sock_filter_int *insn = tmp_insns; | |
863 | ||
864 | if (addrs) | |
865 | addrs[i] = new_insn - new_prog; | |
866 | ||
867 | switch (fp->code) { | |
868 | /* All arithmetic insns and skb loads map as-is. */ | |
869 | case BPF_ALU | BPF_ADD | BPF_X: | |
870 | case BPF_ALU | BPF_ADD | BPF_K: | |
871 | case BPF_ALU | BPF_SUB | BPF_X: | |
872 | case BPF_ALU | BPF_SUB | BPF_K: | |
873 | case BPF_ALU | BPF_AND | BPF_X: | |
874 | case BPF_ALU | BPF_AND | BPF_K: | |
875 | case BPF_ALU | BPF_OR | BPF_X: | |
876 | case BPF_ALU | BPF_OR | BPF_K: | |
877 | case BPF_ALU | BPF_LSH | BPF_X: | |
878 | case BPF_ALU | BPF_LSH | BPF_K: | |
879 | case BPF_ALU | BPF_RSH | BPF_X: | |
880 | case BPF_ALU | BPF_RSH | BPF_K: | |
881 | case BPF_ALU | BPF_XOR | BPF_X: | |
882 | case BPF_ALU | BPF_XOR | BPF_K: | |
883 | case BPF_ALU | BPF_MUL | BPF_X: | |
884 | case BPF_ALU | BPF_MUL | BPF_K: | |
885 | case BPF_ALU | BPF_DIV | BPF_X: | |
886 | case BPF_ALU | BPF_DIV | BPF_K: | |
887 | case BPF_ALU | BPF_MOD | BPF_X: | |
888 | case BPF_ALU | BPF_MOD | BPF_K: | |
889 | case BPF_ALU | BPF_NEG: | |
890 | case BPF_LD | BPF_ABS | BPF_W: | |
891 | case BPF_LD | BPF_ABS | BPF_H: | |
892 | case BPF_LD | BPF_ABS | BPF_B: | |
893 | case BPF_LD | BPF_IND | BPF_W: | |
894 | case BPF_LD | BPF_IND | BPF_H: | |
895 | case BPF_LD | BPF_IND | BPF_B: | |
896 | /* Check for overloaded BPF extension and | |
897 | * directly convert it if found, otherwise | |
898 | * just move on with mapping. | |
899 | */ | |
900 | if (BPF_CLASS(fp->code) == BPF_LD && | |
901 | BPF_MODE(fp->code) == BPF_ABS && | |
902 | convert_bpf_extensions(fp, &insn)) | |
903 | break; | |
904 | ||
f8f6d679 | 905 | *insn = BPF_RAW_INSN(fp->code, BPF_REG_A, BPF_REG_X, 0, fp->k); |
bd4cf0ed AS |
906 | break; |
907 | ||
f8f6d679 DB |
908 | /* Jump transformation cannot use BPF block macros |
909 | * everywhere as offset calculation and target updates | |
910 | * require a bit more work than the rest, i.e. jump | |
911 | * opcodes map as-is, but offsets need adjustment. | |
912 | */ | |
913 | ||
914 | #define BPF_EMIT_JMP \ | |
bd4cf0ed AS |
915 | do { \ |
916 | if (target >= len || target < 0) \ | |
917 | goto err; \ | |
918 | insn->off = addrs ? addrs[target] - addrs[i] - 1 : 0; \ | |
919 | /* Adjust pc relative offset for 2nd or 3rd insn. */ \ | |
920 | insn->off -= insn - tmp_insns; \ | |
921 | } while (0) | |
922 | ||
f8f6d679 DB |
923 | case BPF_JMP | BPF_JA: |
924 | target = i + fp->k + 1; | |
925 | insn->code = fp->code; | |
926 | BPF_EMIT_JMP; | |
bd4cf0ed AS |
927 | break; |
928 | ||
929 | case BPF_JMP | BPF_JEQ | BPF_K: | |
930 | case BPF_JMP | BPF_JEQ | BPF_X: | |
931 | case BPF_JMP | BPF_JSET | BPF_K: | |
932 | case BPF_JMP | BPF_JSET | BPF_X: | |
933 | case BPF_JMP | BPF_JGT | BPF_K: | |
934 | case BPF_JMP | BPF_JGT | BPF_X: | |
935 | case BPF_JMP | BPF_JGE | BPF_K: | |
936 | case BPF_JMP | BPF_JGE | BPF_X: | |
937 | if (BPF_SRC(fp->code) == BPF_K && (int) fp->k < 0) { | |
938 | /* BPF immediates are signed, zero extend | |
939 | * immediate into tmp register and use it | |
940 | * in compare insn. | |
941 | */ | |
f8f6d679 | 942 | *insn++ = BPF_MOV32_IMM(BPF_REG_TMP, fp->k); |
bd4cf0ed | 943 | |
e430f34e AS |
944 | insn->dst_reg = BPF_REG_A; |
945 | insn->src_reg = BPF_REG_TMP; | |
bd4cf0ed AS |
946 | bpf_src = BPF_X; |
947 | } else { | |
e430f34e AS |
948 | insn->dst_reg = BPF_REG_A; |
949 | insn->src_reg = BPF_REG_X; | |
bd4cf0ed AS |
950 | insn->imm = fp->k; |
951 | bpf_src = BPF_SRC(fp->code); | |
1da177e4 | 952 | } |
bd4cf0ed AS |
953 | |
954 | /* Common case where 'jump_false' is next insn. */ | |
955 | if (fp->jf == 0) { | |
956 | insn->code = BPF_JMP | BPF_OP(fp->code) | bpf_src; | |
957 | target = i + fp->jt + 1; | |
f8f6d679 | 958 | BPF_EMIT_JMP; |
bd4cf0ed | 959 | break; |
1da177e4 | 960 | } |
bd4cf0ed AS |
961 | |
962 | /* Convert JEQ into JNE when 'jump_true' is next insn. */ | |
963 | if (fp->jt == 0 && BPF_OP(fp->code) == BPF_JEQ) { | |
964 | insn->code = BPF_JMP | BPF_JNE | bpf_src; | |
965 | target = i + fp->jf + 1; | |
f8f6d679 | 966 | BPF_EMIT_JMP; |
bd4cf0ed | 967 | break; |
0b05b2a4 | 968 | } |
bd4cf0ed AS |
969 | |
970 | /* Other jumps are mapped into two insns: Jxx and JA. */ | |
971 | target = i + fp->jt + 1; | |
972 | insn->code = BPF_JMP | BPF_OP(fp->code) | bpf_src; | |
f8f6d679 | 973 | BPF_EMIT_JMP; |
bd4cf0ed AS |
974 | insn++; |
975 | ||
976 | insn->code = BPF_JMP | BPF_JA; | |
977 | target = i + fp->jf + 1; | |
f8f6d679 | 978 | BPF_EMIT_JMP; |
bd4cf0ed AS |
979 | break; |
980 | ||
981 | /* ldxb 4 * ([14] & 0xf) is remaped into 6 insns. */ | |
982 | case BPF_LDX | BPF_MSH | BPF_B: | |
9739eef1 | 983 | /* tmp = A */ |
f8f6d679 | 984 | *insn++ = BPF_MOV64_REG(BPF_REG_TMP, BPF_REG_A); |
1268e253 | 985 | /* A = BPF_R0 = *(u8 *) (skb->data + K) */ |
f8f6d679 | 986 | *insn++ = BPF_LD_ABS(BPF_B, fp->k); |
9739eef1 | 987 | /* A &= 0xf */ |
f8f6d679 | 988 | *insn++ = BPF_ALU32_IMM(BPF_AND, BPF_REG_A, 0xf); |
9739eef1 | 989 | /* A <<= 2 */ |
f8f6d679 | 990 | *insn++ = BPF_ALU32_IMM(BPF_LSH, BPF_REG_A, 2); |
9739eef1 | 991 | /* X = A */ |
f8f6d679 | 992 | *insn++ = BPF_MOV64_REG(BPF_REG_X, BPF_REG_A); |
9739eef1 | 993 | /* A = tmp */ |
f8f6d679 | 994 | *insn = BPF_MOV64_REG(BPF_REG_A, BPF_REG_TMP); |
bd4cf0ed AS |
995 | break; |
996 | ||
997 | /* RET_K, RET_A are remaped into 2 insns. */ | |
998 | case BPF_RET | BPF_A: | |
999 | case BPF_RET | BPF_K: | |
f8f6d679 DB |
1000 | *insn++ = BPF_MOV32_RAW(BPF_RVAL(fp->code) == BPF_K ? |
1001 | BPF_K : BPF_X, BPF_REG_0, | |
1002 | BPF_REG_A, fp->k); | |
9739eef1 | 1003 | *insn = BPF_EXIT_INSN(); |
bd4cf0ed AS |
1004 | break; |
1005 | ||
1006 | /* Store to stack. */ | |
1007 | case BPF_ST: | |
1008 | case BPF_STX: | |
f8f6d679 DB |
1009 | *insn = BPF_STX_MEM(BPF_W, BPF_REG_FP, BPF_CLASS(fp->code) == |
1010 | BPF_ST ? BPF_REG_A : BPF_REG_X, | |
1011 | -(BPF_MEMWORDS - fp->k) * 4); | |
bd4cf0ed AS |
1012 | break; |
1013 | ||
1014 | /* Load from stack. */ | |
1015 | case BPF_LD | BPF_MEM: | |
1016 | case BPF_LDX | BPF_MEM: | |
f8f6d679 DB |
1017 | *insn = BPF_LDX_MEM(BPF_W, BPF_CLASS(fp->code) == BPF_LD ? |
1018 | BPF_REG_A : BPF_REG_X, BPF_REG_FP, | |
1019 | -(BPF_MEMWORDS - fp->k) * 4); | |
bd4cf0ed AS |
1020 | break; |
1021 | ||
1022 | /* A = K or X = K */ | |
1023 | case BPF_LD | BPF_IMM: | |
1024 | case BPF_LDX | BPF_IMM: | |
f8f6d679 DB |
1025 | *insn = BPF_MOV32_IMM(BPF_CLASS(fp->code) == BPF_LD ? |
1026 | BPF_REG_A : BPF_REG_X, fp->k); | |
bd4cf0ed AS |
1027 | break; |
1028 | ||
1029 | /* X = A */ | |
1030 | case BPF_MISC | BPF_TAX: | |
f8f6d679 | 1031 | *insn = BPF_MOV64_REG(BPF_REG_X, BPF_REG_A); |
bd4cf0ed AS |
1032 | break; |
1033 | ||
1034 | /* A = X */ | |
1035 | case BPF_MISC | BPF_TXA: | |
f8f6d679 | 1036 | *insn = BPF_MOV64_REG(BPF_REG_A, BPF_REG_X); |
bd4cf0ed AS |
1037 | break; |
1038 | ||
1039 | /* A = skb->len or X = skb->len */ | |
1040 | case BPF_LD | BPF_W | BPF_LEN: | |
1041 | case BPF_LDX | BPF_W | BPF_LEN: | |
f8f6d679 DB |
1042 | *insn = BPF_LDX_MEM(BPF_W, BPF_CLASS(fp->code) == BPF_LD ? |
1043 | BPF_REG_A : BPF_REG_X, BPF_REG_CTX, | |
1044 | offsetof(struct sk_buff, len)); | |
bd4cf0ed AS |
1045 | break; |
1046 | ||
f8f6d679 | 1047 | /* Access seccomp_data fields. */ |
bd4cf0ed | 1048 | case BPF_LDX | BPF_ABS | BPF_W: |
9739eef1 AS |
1049 | /* A = *(u32 *) (ctx + K) */ |
1050 | *insn = BPF_LDX_MEM(BPF_W, BPF_REG_A, BPF_REG_CTX, fp->k); | |
bd4cf0ed AS |
1051 | break; |
1052 | ||
f8f6d679 | 1053 | /* Unkown instruction. */ |
1da177e4 | 1054 | default: |
bd4cf0ed | 1055 | goto err; |
1da177e4 | 1056 | } |
bd4cf0ed AS |
1057 | |
1058 | insn++; | |
1059 | if (new_prog) | |
1060 | memcpy(new_insn, tmp_insns, | |
1061 | sizeof(*insn) * (insn - tmp_insns)); | |
bd4cf0ed | 1062 | new_insn += insn - tmp_insns; |
1da177e4 LT |
1063 | } |
1064 | ||
bd4cf0ed AS |
1065 | if (!new_prog) { |
1066 | /* Only calculating new length. */ | |
1067 | *new_len = new_insn - new_prog; | |
1068 | return 0; | |
1069 | } | |
1070 | ||
1071 | pass++; | |
1072 | if (new_flen != new_insn - new_prog) { | |
1073 | new_flen = new_insn - new_prog; | |
1074 | if (pass > 2) | |
1075 | goto err; | |
bd4cf0ed AS |
1076 | goto do_pass; |
1077 | } | |
1078 | ||
1079 | kfree(addrs); | |
1080 | BUG_ON(*new_len != new_flen); | |
1da177e4 | 1081 | return 0; |
bd4cf0ed AS |
1082 | err: |
1083 | kfree(addrs); | |
1084 | return -EINVAL; | |
1da177e4 LT |
1085 | } |
1086 | ||
bd4cf0ed AS |
1087 | /* Security: |
1088 | * | |
2d5311e4 | 1089 | * A BPF program is able to use 16 cells of memory to store intermediate |
bd4cf0ed AS |
1090 | * values (check u32 mem[BPF_MEMWORDS] in sk_run_filter()). |
1091 | * | |
2d5311e4 ED |
1092 | * As we dont want to clear mem[] array for each packet going through |
1093 | * sk_run_filter(), we check that filter loaded by user never try to read | |
1094 | * a cell if not previously written, and we check all branches to be sure | |
25985edc | 1095 | * a malicious user doesn't try to abuse us. |
2d5311e4 ED |
1096 | */ |
1097 | static int check_load_and_stores(struct sock_filter *filter, int flen) | |
1098 | { | |
34805931 | 1099 | u16 *masks, memvalid = 0; /* One bit per cell, 16 cells */ |
2d5311e4 ED |
1100 | int pc, ret = 0; |
1101 | ||
1102 | BUILD_BUG_ON(BPF_MEMWORDS > 16); | |
34805931 | 1103 | |
2d5311e4 ED |
1104 | masks = kmalloc(flen * sizeof(*masks), GFP_KERNEL); |
1105 | if (!masks) | |
1106 | return -ENOMEM; | |
34805931 | 1107 | |
2d5311e4 ED |
1108 | memset(masks, 0xff, flen * sizeof(*masks)); |
1109 | ||
1110 | for (pc = 0; pc < flen; pc++) { | |
1111 | memvalid &= masks[pc]; | |
1112 | ||
1113 | switch (filter[pc].code) { | |
34805931 DB |
1114 | case BPF_ST: |
1115 | case BPF_STX: | |
2d5311e4 ED |
1116 | memvalid |= (1 << filter[pc].k); |
1117 | break; | |
34805931 DB |
1118 | case BPF_LD | BPF_MEM: |
1119 | case BPF_LDX | BPF_MEM: | |
2d5311e4 ED |
1120 | if (!(memvalid & (1 << filter[pc].k))) { |
1121 | ret = -EINVAL; | |
1122 | goto error; | |
1123 | } | |
1124 | break; | |
34805931 DB |
1125 | case BPF_JMP | BPF_JA: |
1126 | /* A jump must set masks on target */ | |
2d5311e4 ED |
1127 | masks[pc + 1 + filter[pc].k] &= memvalid; |
1128 | memvalid = ~0; | |
1129 | break; | |
34805931 DB |
1130 | case BPF_JMP | BPF_JEQ | BPF_K: |
1131 | case BPF_JMP | BPF_JEQ | BPF_X: | |
1132 | case BPF_JMP | BPF_JGE | BPF_K: | |
1133 | case BPF_JMP | BPF_JGE | BPF_X: | |
1134 | case BPF_JMP | BPF_JGT | BPF_K: | |
1135 | case BPF_JMP | BPF_JGT | BPF_X: | |
1136 | case BPF_JMP | BPF_JSET | BPF_K: | |
1137 | case BPF_JMP | BPF_JSET | BPF_X: | |
1138 | /* A jump must set masks on targets */ | |
2d5311e4 ED |
1139 | masks[pc + 1 + filter[pc].jt] &= memvalid; |
1140 | masks[pc + 1 + filter[pc].jf] &= memvalid; | |
1141 | memvalid = ~0; | |
1142 | break; | |
1143 | } | |
1144 | } | |
1145 | error: | |
1146 | kfree(masks); | |
1147 | return ret; | |
1148 | } | |
1149 | ||
34805931 DB |
1150 | static bool chk_code_allowed(u16 code_to_probe) |
1151 | { | |
1152 | static const bool codes[] = { | |
1153 | /* 32 bit ALU operations */ | |
1154 | [BPF_ALU | BPF_ADD | BPF_K] = true, | |
1155 | [BPF_ALU | BPF_ADD | BPF_X] = true, | |
1156 | [BPF_ALU | BPF_SUB | BPF_K] = true, | |
1157 | [BPF_ALU | BPF_SUB | BPF_X] = true, | |
1158 | [BPF_ALU | BPF_MUL | BPF_K] = true, | |
1159 | [BPF_ALU | BPF_MUL | BPF_X] = true, | |
1160 | [BPF_ALU | BPF_DIV | BPF_K] = true, | |
1161 | [BPF_ALU | BPF_DIV | BPF_X] = true, | |
1162 | [BPF_ALU | BPF_MOD | BPF_K] = true, | |
1163 | [BPF_ALU | BPF_MOD | BPF_X] = true, | |
1164 | [BPF_ALU | BPF_AND | BPF_K] = true, | |
1165 | [BPF_ALU | BPF_AND | BPF_X] = true, | |
1166 | [BPF_ALU | BPF_OR | BPF_K] = true, | |
1167 | [BPF_ALU | BPF_OR | BPF_X] = true, | |
1168 | [BPF_ALU | BPF_XOR | BPF_K] = true, | |
1169 | [BPF_ALU | BPF_XOR | BPF_X] = true, | |
1170 | [BPF_ALU | BPF_LSH | BPF_K] = true, | |
1171 | [BPF_ALU | BPF_LSH | BPF_X] = true, | |
1172 | [BPF_ALU | BPF_RSH | BPF_K] = true, | |
1173 | [BPF_ALU | BPF_RSH | BPF_X] = true, | |
1174 | [BPF_ALU | BPF_NEG] = true, | |
1175 | /* Load instructions */ | |
1176 | [BPF_LD | BPF_W | BPF_ABS] = true, | |
1177 | [BPF_LD | BPF_H | BPF_ABS] = true, | |
1178 | [BPF_LD | BPF_B | BPF_ABS] = true, | |
1179 | [BPF_LD | BPF_W | BPF_LEN] = true, | |
1180 | [BPF_LD | BPF_W | BPF_IND] = true, | |
1181 | [BPF_LD | BPF_H | BPF_IND] = true, | |
1182 | [BPF_LD | BPF_B | BPF_IND] = true, | |
1183 | [BPF_LD | BPF_IMM] = true, | |
1184 | [BPF_LD | BPF_MEM] = true, | |
1185 | [BPF_LDX | BPF_W | BPF_LEN] = true, | |
1186 | [BPF_LDX | BPF_B | BPF_MSH] = true, | |
1187 | [BPF_LDX | BPF_IMM] = true, | |
1188 | [BPF_LDX | BPF_MEM] = true, | |
1189 | /* Store instructions */ | |
1190 | [BPF_ST] = true, | |
1191 | [BPF_STX] = true, | |
1192 | /* Misc instructions */ | |
1193 | [BPF_MISC | BPF_TAX] = true, | |
1194 | [BPF_MISC | BPF_TXA] = true, | |
1195 | /* Return instructions */ | |
1196 | [BPF_RET | BPF_K] = true, | |
1197 | [BPF_RET | BPF_A] = true, | |
1198 | /* Jump instructions */ | |
1199 | [BPF_JMP | BPF_JA] = true, | |
1200 | [BPF_JMP | BPF_JEQ | BPF_K] = true, | |
1201 | [BPF_JMP | BPF_JEQ | BPF_X] = true, | |
1202 | [BPF_JMP | BPF_JGE | BPF_K] = true, | |
1203 | [BPF_JMP | BPF_JGE | BPF_X] = true, | |
1204 | [BPF_JMP | BPF_JGT | BPF_K] = true, | |
1205 | [BPF_JMP | BPF_JGT | BPF_X] = true, | |
1206 | [BPF_JMP | BPF_JSET | BPF_K] = true, | |
1207 | [BPF_JMP | BPF_JSET | BPF_X] = true, | |
1208 | }; | |
1209 | ||
1210 | if (code_to_probe >= ARRAY_SIZE(codes)) | |
1211 | return false; | |
1212 | ||
1213 | return codes[code_to_probe]; | |
1214 | } | |
1215 | ||
1da177e4 LT |
1216 | /** |
1217 | * sk_chk_filter - verify socket filter code | |
1218 | * @filter: filter to verify | |
1219 | * @flen: length of filter | |
1220 | * | |
1221 | * Check the user's filter code. If we let some ugly | |
1222 | * filter code slip through kaboom! The filter must contain | |
93699863 KK |
1223 | * no references or jumps that are out of range, no illegal |
1224 | * instructions, and must end with a RET instruction. | |
1da177e4 | 1225 | * |
7b11f69f KK |
1226 | * All jumps are forward as they are not signed. |
1227 | * | |
1228 | * Returns 0 if the rule set is legal or -EINVAL if not. | |
1da177e4 | 1229 | */ |
4f25af27 | 1230 | int sk_chk_filter(struct sock_filter *filter, unsigned int flen) |
1da177e4 | 1231 | { |
aa1113d9 | 1232 | bool anc_found; |
34805931 | 1233 | int pc; |
1da177e4 | 1234 | |
1b93ae64 | 1235 | if (flen == 0 || flen > BPF_MAXINSNS) |
1da177e4 LT |
1236 | return -EINVAL; |
1237 | ||
34805931 | 1238 | /* Check the filter code now */ |
1da177e4 | 1239 | for (pc = 0; pc < flen; pc++) { |
cba328fc | 1240 | struct sock_filter *ftest = &filter[pc]; |
93699863 | 1241 | |
34805931 DB |
1242 | /* May we actually operate on this code? */ |
1243 | if (!chk_code_allowed(ftest->code)) | |
cba328fc | 1244 | return -EINVAL; |
34805931 | 1245 | |
93699863 | 1246 | /* Some instructions need special checks */ |
34805931 DB |
1247 | switch (ftest->code) { |
1248 | case BPF_ALU | BPF_DIV | BPF_K: | |
1249 | case BPF_ALU | BPF_MOD | BPF_K: | |
1250 | /* Check for division by zero */ | |
b6069a95 ED |
1251 | if (ftest->k == 0) |
1252 | return -EINVAL; | |
1253 | break; | |
34805931 DB |
1254 | case BPF_LD | BPF_MEM: |
1255 | case BPF_LDX | BPF_MEM: | |
1256 | case BPF_ST: | |
1257 | case BPF_STX: | |
1258 | /* Check for invalid memory addresses */ | |
93699863 KK |
1259 | if (ftest->k >= BPF_MEMWORDS) |
1260 | return -EINVAL; | |
1261 | break; | |
34805931 DB |
1262 | case BPF_JMP | BPF_JA: |
1263 | /* Note, the large ftest->k might cause loops. | |
93699863 KK |
1264 | * Compare this with conditional jumps below, |
1265 | * where offsets are limited. --ANK (981016) | |
1266 | */ | |
34805931 | 1267 | if (ftest->k >= (unsigned int)(flen - pc - 1)) |
93699863 | 1268 | return -EINVAL; |
01f2f3f6 | 1269 | break; |
34805931 DB |
1270 | case BPF_JMP | BPF_JEQ | BPF_K: |
1271 | case BPF_JMP | BPF_JEQ | BPF_X: | |
1272 | case BPF_JMP | BPF_JGE | BPF_K: | |
1273 | case BPF_JMP | BPF_JGE | BPF_X: | |
1274 | case BPF_JMP | BPF_JGT | BPF_K: | |
1275 | case BPF_JMP | BPF_JGT | BPF_X: | |
1276 | case BPF_JMP | BPF_JSET | BPF_K: | |
1277 | case BPF_JMP | BPF_JSET | BPF_X: | |
1278 | /* Both conditionals must be safe */ | |
e35bedf3 | 1279 | if (pc + ftest->jt + 1 >= flen || |
93699863 KK |
1280 | pc + ftest->jf + 1 >= flen) |
1281 | return -EINVAL; | |
cba328fc | 1282 | break; |
34805931 DB |
1283 | case BPF_LD | BPF_W | BPF_ABS: |
1284 | case BPF_LD | BPF_H | BPF_ABS: | |
1285 | case BPF_LD | BPF_B | BPF_ABS: | |
aa1113d9 | 1286 | anc_found = false; |
34805931 DB |
1287 | if (bpf_anc_helper(ftest) & BPF_ANC) |
1288 | anc_found = true; | |
1289 | /* Ancillary operation unknown or unsupported */ | |
aa1113d9 DB |
1290 | if (anc_found == false && ftest->k >= SKF_AD_OFF) |
1291 | return -EINVAL; | |
01f2f3f6 HPP |
1292 | } |
1293 | } | |
93699863 | 1294 | |
34805931 | 1295 | /* Last instruction must be a RET code */ |
01f2f3f6 | 1296 | switch (filter[flen - 1].code) { |
34805931 DB |
1297 | case BPF_RET | BPF_K: |
1298 | case BPF_RET | BPF_A: | |
2d5311e4 | 1299 | return check_load_and_stores(filter, flen); |
cba328fc | 1300 | } |
34805931 | 1301 | |
cba328fc | 1302 | return -EINVAL; |
1da177e4 | 1303 | } |
b715631f | 1304 | EXPORT_SYMBOL(sk_chk_filter); |
1da177e4 | 1305 | |
a3ea269b DB |
1306 | static int sk_store_orig_filter(struct sk_filter *fp, |
1307 | const struct sock_fprog *fprog) | |
1308 | { | |
1309 | unsigned int fsize = sk_filter_proglen(fprog); | |
1310 | struct sock_fprog_kern *fkprog; | |
1311 | ||
1312 | fp->orig_prog = kmalloc(sizeof(*fkprog), GFP_KERNEL); | |
1313 | if (!fp->orig_prog) | |
1314 | return -ENOMEM; | |
1315 | ||
1316 | fkprog = fp->orig_prog; | |
1317 | fkprog->len = fprog->len; | |
1318 | fkprog->filter = kmemdup(fp->insns, fsize, GFP_KERNEL); | |
1319 | if (!fkprog->filter) { | |
1320 | kfree(fp->orig_prog); | |
1321 | return -ENOMEM; | |
1322 | } | |
1323 | ||
1324 | return 0; | |
1325 | } | |
1326 | ||
1327 | static void sk_release_orig_filter(struct sk_filter *fp) | |
1328 | { | |
1329 | struct sock_fprog_kern *fprog = fp->orig_prog; | |
1330 | ||
1331 | if (fprog) { | |
1332 | kfree(fprog->filter); | |
1333 | kfree(fprog); | |
1334 | } | |
1335 | } | |
1336 | ||
47e958ea | 1337 | /** |
46bcf14f | 1338 | * sk_filter_release_rcu - Release a socket filter by rcu_head |
47e958ea PE |
1339 | * @rcu: rcu_head that contains the sk_filter to free |
1340 | */ | |
fbc907f0 | 1341 | static void sk_filter_release_rcu(struct rcu_head *rcu) |
47e958ea PE |
1342 | { |
1343 | struct sk_filter *fp = container_of(rcu, struct sk_filter, rcu); | |
1344 | ||
a3ea269b | 1345 | sk_release_orig_filter(fp); |
5fe821a9 | 1346 | sk_filter_free(fp); |
47e958ea | 1347 | } |
fbc907f0 DB |
1348 | |
1349 | /** | |
1350 | * sk_filter_release - release a socket filter | |
1351 | * @fp: filter to remove | |
1352 | * | |
1353 | * Remove a filter from a socket and release its resources. | |
1354 | */ | |
1355 | static void sk_filter_release(struct sk_filter *fp) | |
1356 | { | |
1357 | if (atomic_dec_and_test(&fp->refcnt)) | |
1358 | call_rcu(&fp->rcu, sk_filter_release_rcu); | |
1359 | } | |
1360 | ||
1361 | void sk_filter_uncharge(struct sock *sk, struct sk_filter *fp) | |
1362 | { | |
1363 | atomic_sub(sk_filter_size(fp->len), &sk->sk_omem_alloc); | |
1364 | sk_filter_release(fp); | |
1365 | } | |
1366 | ||
1367 | void sk_filter_charge(struct sock *sk, struct sk_filter *fp) | |
1368 | { | |
1369 | atomic_inc(&fp->refcnt); | |
1370 | atomic_add(sk_filter_size(fp->len), &sk->sk_omem_alloc); | |
1371 | } | |
47e958ea | 1372 | |
bd4cf0ed AS |
1373 | static struct sk_filter *__sk_migrate_realloc(struct sk_filter *fp, |
1374 | struct sock *sk, | |
1375 | unsigned int len) | |
1376 | { | |
1377 | struct sk_filter *fp_new; | |
1378 | ||
1379 | if (sk == NULL) | |
1380 | return krealloc(fp, len, GFP_KERNEL); | |
1381 | ||
1382 | fp_new = sock_kmalloc(sk, len, GFP_KERNEL); | |
1383 | if (fp_new) { | |
eb9672f4 | 1384 | *fp_new = *fp; |
285276e7 | 1385 | /* As we're keeping orig_prog in fp_new along, |
bd4cf0ed AS |
1386 | * we need to make sure we're not evicting it |
1387 | * from the old fp. | |
1388 | */ | |
1389 | fp->orig_prog = NULL; | |
1390 | sk_filter_uncharge(sk, fp); | |
1391 | } | |
1392 | ||
1393 | return fp_new; | |
1394 | } | |
1395 | ||
1396 | static struct sk_filter *__sk_migrate_filter(struct sk_filter *fp, | |
1397 | struct sock *sk) | |
1398 | { | |
1399 | struct sock_filter *old_prog; | |
1400 | struct sk_filter *old_fp; | |
34805931 | 1401 | int err, new_len, old_len = fp->len; |
bd4cf0ed AS |
1402 | |
1403 | /* We are free to overwrite insns et al right here as it | |
1404 | * won't be used at this point in time anymore internally | |
1405 | * after the migration to the internal BPF instruction | |
1406 | * representation. | |
1407 | */ | |
1408 | BUILD_BUG_ON(sizeof(struct sock_filter) != | |
1409 | sizeof(struct sock_filter_int)); | |
1410 | ||
bd4cf0ed AS |
1411 | /* Conversion cannot happen on overlapping memory areas, |
1412 | * so we need to keep the user BPF around until the 2nd | |
1413 | * pass. At this time, the user BPF is stored in fp->insns. | |
1414 | */ | |
1415 | old_prog = kmemdup(fp->insns, old_len * sizeof(struct sock_filter), | |
1416 | GFP_KERNEL); | |
1417 | if (!old_prog) { | |
1418 | err = -ENOMEM; | |
1419 | goto out_err; | |
1420 | } | |
1421 | ||
1422 | /* 1st pass: calculate the new program length. */ | |
1423 | err = sk_convert_filter(old_prog, old_len, NULL, &new_len); | |
1424 | if (err) | |
1425 | goto out_err_free; | |
1426 | ||
1427 | /* Expand fp for appending the new filter representation. */ | |
1428 | old_fp = fp; | |
1429 | fp = __sk_migrate_realloc(old_fp, sk, sk_filter_size(new_len)); | |
1430 | if (!fp) { | |
1431 | /* The old_fp is still around in case we couldn't | |
1432 | * allocate new memory, so uncharge on that one. | |
1433 | */ | |
1434 | fp = old_fp; | |
1435 | err = -ENOMEM; | |
1436 | goto out_err_free; | |
1437 | } | |
1438 | ||
bd4cf0ed AS |
1439 | fp->len = new_len; |
1440 | ||
1441 | /* 2nd pass: remap sock_filter insns into sock_filter_int insns. */ | |
1442 | err = sk_convert_filter(old_prog, old_len, fp->insnsi, &new_len); | |
1443 | if (err) | |
1444 | /* 2nd sk_convert_filter() can fail only if it fails | |
1445 | * to allocate memory, remapping must succeed. Note, | |
1446 | * that at this time old_fp has already been released | |
1447 | * by __sk_migrate_realloc(). | |
1448 | */ | |
1449 | goto out_err_free; | |
1450 | ||
5fe821a9 AS |
1451 | sk_filter_select_runtime(fp); |
1452 | ||
bd4cf0ed AS |
1453 | kfree(old_prog); |
1454 | return fp; | |
1455 | ||
1456 | out_err_free: | |
1457 | kfree(old_prog); | |
1458 | out_err: | |
1459 | /* Rollback filter setup. */ | |
1460 | if (sk != NULL) | |
1461 | sk_filter_uncharge(sk, fp); | |
1462 | else | |
1463 | kfree(fp); | |
1464 | return ERR_PTR(err); | |
1465 | } | |
1466 | ||
62258278 AS |
1467 | void __weak bpf_int_jit_compile(struct sk_filter *prog) |
1468 | { | |
1469 | } | |
1470 | ||
5fe821a9 AS |
1471 | /** |
1472 | * sk_filter_select_runtime - select execution runtime for BPF program | |
1473 | * @fp: sk_filter populated with internal BPF program | |
1474 | * | |
1475 | * try to JIT internal BPF program, if JIT is not available select interpreter | |
1476 | * BPF program will be executed via SK_RUN_FILTER() macro | |
1477 | */ | |
1478 | void sk_filter_select_runtime(struct sk_filter *fp) | |
1479 | { | |
1480 | fp->bpf_func = (void *) __sk_run_filter; | |
1481 | ||
1482 | /* Probe if internal BPF can be JITed */ | |
1483 | bpf_int_jit_compile(fp); | |
1484 | } | |
1485 | EXPORT_SYMBOL_GPL(sk_filter_select_runtime); | |
1486 | ||
1487 | /* free internal BPF program */ | |
1488 | void sk_filter_free(struct sk_filter *fp) | |
1489 | { | |
1490 | bpf_jit_free(fp); | |
1491 | } | |
1492 | EXPORT_SYMBOL_GPL(sk_filter_free); | |
1493 | ||
bd4cf0ed AS |
1494 | static struct sk_filter *__sk_prepare_filter(struct sk_filter *fp, |
1495 | struct sock *sk) | |
302d6637 JP |
1496 | { |
1497 | int err; | |
1498 | ||
bd4cf0ed | 1499 | fp->bpf_func = NULL; |
f8bbbfc3 | 1500 | fp->jited = 0; |
302d6637 JP |
1501 | |
1502 | err = sk_chk_filter(fp->insns, fp->len); | |
418c96ac LY |
1503 | if (err) { |
1504 | if (sk != NULL) | |
1505 | sk_filter_uncharge(sk, fp); | |
1506 | else | |
1507 | kfree(fp); | |
bd4cf0ed | 1508 | return ERR_PTR(err); |
418c96ac | 1509 | } |
302d6637 | 1510 | |
bd4cf0ed AS |
1511 | /* Probe if we can JIT compile the filter and if so, do |
1512 | * the compilation of the filter. | |
1513 | */ | |
302d6637 | 1514 | bpf_jit_compile(fp); |
bd4cf0ed AS |
1515 | |
1516 | /* JIT compiler couldn't process this filter, so do the | |
1517 | * internal BPF translation for the optimized interpreter. | |
1518 | */ | |
5fe821a9 | 1519 | if (!fp->jited) |
bd4cf0ed AS |
1520 | fp = __sk_migrate_filter(fp, sk); |
1521 | ||
1522 | return fp; | |
302d6637 JP |
1523 | } |
1524 | ||
1525 | /** | |
1526 | * sk_unattached_filter_create - create an unattached filter | |
1527 | * @fprog: the filter program | |
c6c4b97c | 1528 | * @pfp: the unattached filter that is created |
302d6637 | 1529 | * |
c6c4b97c | 1530 | * Create a filter independent of any socket. We first run some |
302d6637 JP |
1531 | * sanity checks on it to make sure it does not explode on us later. |
1532 | * If an error occurs or there is insufficient memory for the filter | |
1533 | * a negative errno code is returned. On success the return is zero. | |
1534 | */ | |
1535 | int sk_unattached_filter_create(struct sk_filter **pfp, | |
b1fcd35c | 1536 | struct sock_fprog_kern *fprog) |
302d6637 | 1537 | { |
a3ea269b | 1538 | unsigned int fsize = sk_filter_proglen(fprog); |
302d6637 | 1539 | struct sk_filter *fp; |
302d6637 JP |
1540 | |
1541 | /* Make sure new filter is there and in the right amounts. */ | |
1542 | if (fprog->filter == NULL) | |
1543 | return -EINVAL; | |
1544 | ||
d45ed4a4 | 1545 | fp = kmalloc(sk_filter_size(fprog->len), GFP_KERNEL); |
302d6637 JP |
1546 | if (!fp) |
1547 | return -ENOMEM; | |
a3ea269b | 1548 | |
302d6637 JP |
1549 | memcpy(fp->insns, fprog->filter, fsize); |
1550 | ||
1551 | atomic_set(&fp->refcnt, 1); | |
1552 | fp->len = fprog->len; | |
a3ea269b DB |
1553 | /* Since unattached filters are not copied back to user |
1554 | * space through sk_get_filter(), we do not need to hold | |
1555 | * a copy here, and can spare us the work. | |
1556 | */ | |
1557 | fp->orig_prog = NULL; | |
302d6637 | 1558 | |
bd4cf0ed AS |
1559 | /* __sk_prepare_filter() already takes care of uncharging |
1560 | * memory in case something goes wrong. | |
1561 | */ | |
1562 | fp = __sk_prepare_filter(fp, NULL); | |
1563 | if (IS_ERR(fp)) | |
1564 | return PTR_ERR(fp); | |
302d6637 JP |
1565 | |
1566 | *pfp = fp; | |
1567 | return 0; | |
302d6637 JP |
1568 | } |
1569 | EXPORT_SYMBOL_GPL(sk_unattached_filter_create); | |
1570 | ||
1571 | void sk_unattached_filter_destroy(struct sk_filter *fp) | |
1572 | { | |
1573 | sk_filter_release(fp); | |
1574 | } | |
1575 | EXPORT_SYMBOL_GPL(sk_unattached_filter_destroy); | |
1576 | ||
1da177e4 LT |
1577 | /** |
1578 | * sk_attach_filter - attach a socket filter | |
1579 | * @fprog: the filter program | |
1580 | * @sk: the socket to use | |
1581 | * | |
1582 | * Attach the user's filter code. We first run some sanity checks on | |
1583 | * it to make sure it does not explode on us later. If an error | |
1584 | * occurs or there is insufficient memory for the filter a negative | |
1585 | * errno code is returned. On success the return is zero. | |
1586 | */ | |
1587 | int sk_attach_filter(struct sock_fprog *fprog, struct sock *sk) | |
1588 | { | |
d3904b73 | 1589 | struct sk_filter *fp, *old_fp; |
a3ea269b | 1590 | unsigned int fsize = sk_filter_proglen(fprog); |
d45ed4a4 | 1591 | unsigned int sk_fsize = sk_filter_size(fprog->len); |
1da177e4 LT |
1592 | int err; |
1593 | ||
d59577b6 VB |
1594 | if (sock_flag(sk, SOCK_FILTER_LOCKED)) |
1595 | return -EPERM; | |
1596 | ||
1da177e4 | 1597 | /* Make sure new filter is there and in the right amounts. */ |
e35bedf3 KK |
1598 | if (fprog->filter == NULL) |
1599 | return -EINVAL; | |
1da177e4 | 1600 | |
d45ed4a4 | 1601 | fp = sock_kmalloc(sk, sk_fsize, GFP_KERNEL); |
1da177e4 LT |
1602 | if (!fp) |
1603 | return -ENOMEM; | |
a3ea269b | 1604 | |
1da177e4 | 1605 | if (copy_from_user(fp->insns, fprog->filter, fsize)) { |
d45ed4a4 | 1606 | sock_kfree_s(sk, fp, sk_fsize); |
1da177e4 LT |
1607 | return -EFAULT; |
1608 | } | |
1609 | ||
1610 | atomic_set(&fp->refcnt, 1); | |
1611 | fp->len = fprog->len; | |
1612 | ||
a3ea269b DB |
1613 | err = sk_store_orig_filter(fp, fprog); |
1614 | if (err) { | |
1615 | sk_filter_uncharge(sk, fp); | |
1616 | return -ENOMEM; | |
1617 | } | |
1618 | ||
bd4cf0ed AS |
1619 | /* __sk_prepare_filter() already takes care of uncharging |
1620 | * memory in case something goes wrong. | |
1621 | */ | |
1622 | fp = __sk_prepare_filter(fp, sk); | |
1623 | if (IS_ERR(fp)) | |
1624 | return PTR_ERR(fp); | |
1da177e4 | 1625 | |
f91ff5b9 ED |
1626 | old_fp = rcu_dereference_protected(sk->sk_filter, |
1627 | sock_owned_by_user(sk)); | |
d3904b73 | 1628 | rcu_assign_pointer(sk->sk_filter, fp); |
d3904b73 | 1629 | |
9b013e05 | 1630 | if (old_fp) |
46bcf14f | 1631 | sk_filter_uncharge(sk, old_fp); |
a3ea269b | 1632 | |
d3904b73 | 1633 | return 0; |
1da177e4 | 1634 | } |
5ff3f073 | 1635 | EXPORT_SYMBOL_GPL(sk_attach_filter); |
1da177e4 | 1636 | |
55b33325 PE |
1637 | int sk_detach_filter(struct sock *sk) |
1638 | { | |
1639 | int ret = -ENOENT; | |
1640 | struct sk_filter *filter; | |
1641 | ||
d59577b6 VB |
1642 | if (sock_flag(sk, SOCK_FILTER_LOCKED)) |
1643 | return -EPERM; | |
1644 | ||
f91ff5b9 ED |
1645 | filter = rcu_dereference_protected(sk->sk_filter, |
1646 | sock_owned_by_user(sk)); | |
55b33325 | 1647 | if (filter) { |
a9b3cd7f | 1648 | RCU_INIT_POINTER(sk->sk_filter, NULL); |
46bcf14f | 1649 | sk_filter_uncharge(sk, filter); |
55b33325 PE |
1650 | ret = 0; |
1651 | } | |
a3ea269b | 1652 | |
55b33325 PE |
1653 | return ret; |
1654 | } | |
5ff3f073 | 1655 | EXPORT_SYMBOL_GPL(sk_detach_filter); |
a8fc9277 | 1656 | |
a3ea269b DB |
1657 | int sk_get_filter(struct sock *sk, struct sock_filter __user *ubuf, |
1658 | unsigned int len) | |
a8fc9277 | 1659 | { |
a3ea269b | 1660 | struct sock_fprog_kern *fprog; |
a8fc9277 | 1661 | struct sk_filter *filter; |
a3ea269b | 1662 | int ret = 0; |
a8fc9277 PE |
1663 | |
1664 | lock_sock(sk); | |
1665 | filter = rcu_dereference_protected(sk->sk_filter, | |
a3ea269b | 1666 | sock_owned_by_user(sk)); |
a8fc9277 PE |
1667 | if (!filter) |
1668 | goto out; | |
a3ea269b DB |
1669 | |
1670 | /* We're copying the filter that has been originally attached, | |
1671 | * so no conversion/decode needed anymore. | |
1672 | */ | |
1673 | fprog = filter->orig_prog; | |
1674 | ||
1675 | ret = fprog->len; | |
a8fc9277 | 1676 | if (!len) |
a3ea269b | 1677 | /* User space only enquires number of filter blocks. */ |
a8fc9277 | 1678 | goto out; |
a3ea269b | 1679 | |
a8fc9277 | 1680 | ret = -EINVAL; |
a3ea269b | 1681 | if (len < fprog->len) |
a8fc9277 PE |
1682 | goto out; |
1683 | ||
1684 | ret = -EFAULT; | |
a3ea269b DB |
1685 | if (copy_to_user(ubuf, fprog->filter, sk_filter_proglen(fprog))) |
1686 | goto out; | |
a8fc9277 | 1687 | |
a3ea269b DB |
1688 | /* Instead of bytes, the API requests to return the number |
1689 | * of filter blocks. | |
1690 | */ | |
1691 | ret = fprog->len; | |
a8fc9277 PE |
1692 | out: |
1693 | release_sock(sk); | |
1694 | return ret; | |
1695 | } |