Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 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. |
Kris Katterjohn | 9369986 | 2006-01-04 13:58:36 -0800 | [diff] [blame] | 16 | * Kris Katterjohn - Added many additional checks in sk_chk_filter() |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 17 | */ |
| 18 | |
| 19 | #include <linux/module.h> |
| 20 | #include <linux/types.h> |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 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> |
Tejun Heo | 5a0e3ad | 2010-03-24 17:04:11 +0900 | [diff] [blame] | 28 | #include <linux/gfp.h> |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 29 | #include <net/ip.h> |
| 30 | #include <net/protocol.h> |
Patrick McHardy | 4738c1d | 2008-04-10 02:02:28 -0700 | [diff] [blame] | 31 | #include <net/netlink.h> |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 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> |
Dmitry Mishin | 40daafc | 2006-04-18 14:50:10 -0700 | [diff] [blame] | 38 | #include <asm/unaligned.h> |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 39 | #include <linux/filter.h> |
| 40 | |
| 41 | /* No hurry in this branch */ |
Patrick McHardy | 0b05b2a | 2005-07-05 14:10:21 -0700 | [diff] [blame] | 42 | static void *__load_pointer(struct sk_buff *skb, int k) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 43 | { |
| 44 | u8 *ptr = NULL; |
| 45 | |
| 46 | if (k >= SKF_NET_OFF) |
Arnaldo Carvalho de Melo | d56f90a | 2007-04-10 20:50:43 -0700 | [diff] [blame] | 47 | ptr = skb_network_header(skb) + k - SKF_NET_OFF; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 48 | else if (k >= SKF_LL_OFF) |
Arnaldo Carvalho de Melo | 98e399f | 2007-03-19 15:33:04 -0700 | [diff] [blame] | 49 | ptr = skb_mac_header(skb) + k - SKF_LL_OFF; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 50 | |
Arnaldo Carvalho de Melo | 27a884d | 2007-04-19 20:29:13 -0700 | [diff] [blame] | 51 | if (ptr >= skb->head && ptr < skb_tail_pointer(skb)) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 52 | return ptr; |
| 53 | return NULL; |
| 54 | } |
| 55 | |
Patrick McHardy | 0b05b2a | 2005-07-05 14:10:21 -0700 | [diff] [blame] | 56 | static inline void *load_pointer(struct sk_buff *skb, int k, |
YOSHIFUJI Hideaki | 4ec93ed | 2007-02-09 23:24:36 +0900 | [diff] [blame] | 57 | unsigned int size, void *buffer) |
Patrick McHardy | 0b05b2a | 2005-07-05 14:10:21 -0700 | [diff] [blame] | 58 | { |
| 59 | if (k >= 0) |
| 60 | return skb_header_pointer(skb, k, size, buffer); |
| 61 | else { |
| 62 | if (k >= SKF_AD_OFF) |
| 63 | return NULL; |
| 64 | return __load_pointer(skb, k); |
| 65 | } |
| 66 | } |
| 67 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 68 | /** |
Stephen Hemminger | 43db6d6 | 2008-04-10 01:43:09 -0700 | [diff] [blame] | 69 | * sk_filter - run a packet through a socket filter |
| 70 | * @sk: sock associated with &sk_buff |
| 71 | * @skb: buffer to filter |
Stephen Hemminger | 43db6d6 | 2008-04-10 01:43:09 -0700 | [diff] [blame] | 72 | * |
| 73 | * Run the filter code and then cut skb->data to correct size returned by |
| 74 | * sk_run_filter. If pkt_len is 0 we toss packet. If skb->len is smaller |
| 75 | * than pkt_len we keep whole skb->data. This is the socket level |
| 76 | * wrapper to sk_run_filter. It returns 0 if the packet should |
| 77 | * be accepted or -EPERM if the packet should be tossed. |
| 78 | * |
| 79 | */ |
| 80 | int sk_filter(struct sock *sk, struct sk_buff *skb) |
| 81 | { |
| 82 | int err; |
| 83 | struct sk_filter *filter; |
| 84 | |
| 85 | err = security_sock_rcv_skb(sk, skb); |
| 86 | if (err) |
| 87 | return err; |
| 88 | |
| 89 | rcu_read_lock_bh(); |
Paul E. McKenney | a898def | 2010-02-22 17:04:49 -0800 | [diff] [blame] | 90 | filter = rcu_dereference_bh(sk->sk_filter); |
Stephen Hemminger | 43db6d6 | 2008-04-10 01:43:09 -0700 | [diff] [blame] | 91 | if (filter) { |
| 92 | unsigned int pkt_len = sk_run_filter(skb, filter->insns, |
| 93 | filter->len); |
| 94 | err = pkt_len ? pskb_trim(skb, pkt_len) : -EPERM; |
| 95 | } |
| 96 | rcu_read_unlock_bh(); |
| 97 | |
| 98 | return err; |
| 99 | } |
| 100 | EXPORT_SYMBOL(sk_filter); |
| 101 | |
| 102 | /** |
Kris Katterjohn | 2966b66 | 2006-01-23 16:26:16 -0800 | [diff] [blame] | 103 | * sk_run_filter - run a filter on a socket |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 104 | * @skb: buffer to run the filter on |
| 105 | * @filter: filter to apply |
| 106 | * @flen: length of filter |
| 107 | * |
| 108 | * Decode and apply filter instructions to the skb->data. |
| 109 | * Return length to keep, 0 for none. skb is the data we are |
| 110 | * filtering, filter is the array of filter instructions, and |
| 111 | * len is the number of filter blocks in the array. |
| 112 | */ |
Kris Katterjohn | 4bad4dc | 2006-01-06 13:08:20 -0800 | [diff] [blame] | 113 | unsigned int sk_run_filter(struct sk_buff *skb, struct sock_filter *filter, int flen) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 114 | { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 115 | struct sock_filter *fentry; /* We walk down these */ |
Patrick McHardy | 0b05b2a | 2005-07-05 14:10:21 -0700 | [diff] [blame] | 116 | void *ptr; |
Kris Katterjohn | 2966b66 | 2006-01-23 16:26:16 -0800 | [diff] [blame] | 117 | u32 A = 0; /* Accumulator */ |
| 118 | u32 X = 0; /* Index Register */ |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 119 | u32 mem[BPF_MEMWORDS]; /* Scratch Memory Store */ |
Patrick McHardy | 0b05b2a | 2005-07-05 14:10:21 -0700 | [diff] [blame] | 120 | u32 tmp; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 121 | int k; |
| 122 | int pc; |
| 123 | |
| 124 | /* |
| 125 | * Process array of filter instructions. |
| 126 | */ |
| 127 | for (pc = 0; pc < flen; pc++) { |
| 128 | fentry = &filter[pc]; |
YOSHIFUJI Hideaki | 4ec93ed | 2007-02-09 23:24:36 +0900 | [diff] [blame] | 129 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 130 | switch (fentry->code) { |
Hagen Paul Pfeifer | 01f2f3f | 2010-06-19 17:05:36 +0000 | [diff] [blame] | 131 | case BPF_S_ALU_ADD_X: |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 132 | A += X; |
| 133 | continue; |
Hagen Paul Pfeifer | 01f2f3f | 2010-06-19 17:05:36 +0000 | [diff] [blame] | 134 | case BPF_S_ALU_ADD_K: |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 135 | A += fentry->k; |
| 136 | continue; |
Hagen Paul Pfeifer | 01f2f3f | 2010-06-19 17:05:36 +0000 | [diff] [blame] | 137 | case BPF_S_ALU_SUB_X: |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 138 | A -= X; |
| 139 | continue; |
Hagen Paul Pfeifer | 01f2f3f | 2010-06-19 17:05:36 +0000 | [diff] [blame] | 140 | case BPF_S_ALU_SUB_K: |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 141 | A -= fentry->k; |
| 142 | continue; |
Hagen Paul Pfeifer | 01f2f3f | 2010-06-19 17:05:36 +0000 | [diff] [blame] | 143 | case BPF_S_ALU_MUL_X: |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 144 | A *= X; |
| 145 | continue; |
Hagen Paul Pfeifer | 01f2f3f | 2010-06-19 17:05:36 +0000 | [diff] [blame] | 146 | case BPF_S_ALU_MUL_K: |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 147 | A *= fentry->k; |
| 148 | continue; |
Hagen Paul Pfeifer | 01f2f3f | 2010-06-19 17:05:36 +0000 | [diff] [blame] | 149 | case BPF_S_ALU_DIV_X: |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 150 | if (X == 0) |
| 151 | return 0; |
| 152 | A /= X; |
| 153 | continue; |
Hagen Paul Pfeifer | 01f2f3f | 2010-06-19 17:05:36 +0000 | [diff] [blame] | 154 | case BPF_S_ALU_DIV_K: |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 155 | A /= fentry->k; |
| 156 | continue; |
Hagen Paul Pfeifer | 01f2f3f | 2010-06-19 17:05:36 +0000 | [diff] [blame] | 157 | case BPF_S_ALU_AND_X: |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 158 | A &= X; |
| 159 | continue; |
Hagen Paul Pfeifer | 01f2f3f | 2010-06-19 17:05:36 +0000 | [diff] [blame] | 160 | case BPF_S_ALU_AND_K: |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 161 | A &= fentry->k; |
| 162 | continue; |
Hagen Paul Pfeifer | 01f2f3f | 2010-06-19 17:05:36 +0000 | [diff] [blame] | 163 | case BPF_S_ALU_OR_X: |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 164 | A |= X; |
| 165 | continue; |
Hagen Paul Pfeifer | 01f2f3f | 2010-06-19 17:05:36 +0000 | [diff] [blame] | 166 | case BPF_S_ALU_OR_K: |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 167 | A |= fentry->k; |
| 168 | continue; |
Hagen Paul Pfeifer | 01f2f3f | 2010-06-19 17:05:36 +0000 | [diff] [blame] | 169 | case BPF_S_ALU_LSH_X: |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 170 | A <<= X; |
| 171 | continue; |
Hagen Paul Pfeifer | 01f2f3f | 2010-06-19 17:05:36 +0000 | [diff] [blame] | 172 | case BPF_S_ALU_LSH_K: |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 173 | A <<= fentry->k; |
| 174 | continue; |
Hagen Paul Pfeifer | 01f2f3f | 2010-06-19 17:05:36 +0000 | [diff] [blame] | 175 | case BPF_S_ALU_RSH_X: |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 176 | A >>= X; |
| 177 | continue; |
Hagen Paul Pfeifer | 01f2f3f | 2010-06-19 17:05:36 +0000 | [diff] [blame] | 178 | case BPF_S_ALU_RSH_K: |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 179 | A >>= fentry->k; |
| 180 | continue; |
Hagen Paul Pfeifer | 01f2f3f | 2010-06-19 17:05:36 +0000 | [diff] [blame] | 181 | case BPF_S_ALU_NEG: |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 182 | A = -A; |
| 183 | continue; |
Hagen Paul Pfeifer | 01f2f3f | 2010-06-19 17:05:36 +0000 | [diff] [blame] | 184 | case BPF_S_JMP_JA: |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 185 | pc += fentry->k; |
| 186 | continue; |
Hagen Paul Pfeifer | 01f2f3f | 2010-06-19 17:05:36 +0000 | [diff] [blame] | 187 | case BPF_S_JMP_JGT_K: |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 188 | pc += (A > fentry->k) ? fentry->jt : fentry->jf; |
| 189 | continue; |
Hagen Paul Pfeifer | 01f2f3f | 2010-06-19 17:05:36 +0000 | [diff] [blame] | 190 | case BPF_S_JMP_JGE_K: |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 191 | pc += (A >= fentry->k) ? fentry->jt : fentry->jf; |
| 192 | continue; |
Hagen Paul Pfeifer | 01f2f3f | 2010-06-19 17:05:36 +0000 | [diff] [blame] | 193 | case BPF_S_JMP_JEQ_K: |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 194 | pc += (A == fentry->k) ? fentry->jt : fentry->jf; |
| 195 | continue; |
Hagen Paul Pfeifer | 01f2f3f | 2010-06-19 17:05:36 +0000 | [diff] [blame] | 196 | case BPF_S_JMP_JSET_K: |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 197 | pc += (A & fentry->k) ? fentry->jt : fentry->jf; |
| 198 | continue; |
Hagen Paul Pfeifer | 01f2f3f | 2010-06-19 17:05:36 +0000 | [diff] [blame] | 199 | case BPF_S_JMP_JGT_X: |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 200 | pc += (A > X) ? fentry->jt : fentry->jf; |
| 201 | continue; |
Hagen Paul Pfeifer | 01f2f3f | 2010-06-19 17:05:36 +0000 | [diff] [blame] | 202 | case BPF_S_JMP_JGE_X: |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 203 | pc += (A >= X) ? fentry->jt : fentry->jf; |
| 204 | continue; |
Hagen Paul Pfeifer | 01f2f3f | 2010-06-19 17:05:36 +0000 | [diff] [blame] | 205 | case BPF_S_JMP_JEQ_X: |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 206 | pc += (A == X) ? fentry->jt : fentry->jf; |
| 207 | continue; |
Hagen Paul Pfeifer | 01f2f3f | 2010-06-19 17:05:36 +0000 | [diff] [blame] | 208 | case BPF_S_JMP_JSET_X: |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 209 | pc += (A & X) ? fentry->jt : fentry->jf; |
| 210 | continue; |
Hagen Paul Pfeifer | 01f2f3f | 2010-06-19 17:05:36 +0000 | [diff] [blame] | 211 | case BPF_S_LD_W_ABS: |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 212 | k = fentry->k; |
Kris Katterjohn | e35bedf | 2006-01-17 02:25:52 -0800 | [diff] [blame] | 213 | load_w: |
Patrick McHardy | 0b05b2a | 2005-07-05 14:10:21 -0700 | [diff] [blame] | 214 | ptr = load_pointer(skb, k, 4, &tmp); |
| 215 | if (ptr != NULL) { |
Harvey Harrison | d3e2ce3 | 2008-05-02 16:26:16 -0700 | [diff] [blame] | 216 | A = get_unaligned_be32(ptr); |
Patrick McHardy | 0b05b2a | 2005-07-05 14:10:21 -0700 | [diff] [blame] | 217 | continue; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 218 | } |
Herbert Xu | 1198ad0 | 2005-09-05 18:44:37 -0700 | [diff] [blame] | 219 | break; |
Hagen Paul Pfeifer | 01f2f3f | 2010-06-19 17:05:36 +0000 | [diff] [blame] | 220 | case BPF_S_LD_H_ABS: |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 221 | k = fentry->k; |
Kris Katterjohn | e35bedf | 2006-01-17 02:25:52 -0800 | [diff] [blame] | 222 | load_h: |
Patrick McHardy | 0b05b2a | 2005-07-05 14:10:21 -0700 | [diff] [blame] | 223 | ptr = load_pointer(skb, k, 2, &tmp); |
| 224 | if (ptr != NULL) { |
Harvey Harrison | d3e2ce3 | 2008-05-02 16:26:16 -0700 | [diff] [blame] | 225 | A = get_unaligned_be16(ptr); |
Patrick McHardy | 0b05b2a | 2005-07-05 14:10:21 -0700 | [diff] [blame] | 226 | continue; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 227 | } |
Herbert Xu | 1198ad0 | 2005-09-05 18:44:37 -0700 | [diff] [blame] | 228 | break; |
Hagen Paul Pfeifer | 01f2f3f | 2010-06-19 17:05:36 +0000 | [diff] [blame] | 229 | case BPF_S_LD_B_ABS: |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 230 | k = fentry->k; |
| 231 | load_b: |
Patrick McHardy | 0b05b2a | 2005-07-05 14:10:21 -0700 | [diff] [blame] | 232 | ptr = load_pointer(skb, k, 1, &tmp); |
| 233 | if (ptr != NULL) { |
| 234 | A = *(u8 *)ptr; |
| 235 | continue; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 236 | } |
Herbert Xu | 1198ad0 | 2005-09-05 18:44:37 -0700 | [diff] [blame] | 237 | break; |
Hagen Paul Pfeifer | 01f2f3f | 2010-06-19 17:05:36 +0000 | [diff] [blame] | 238 | case BPF_S_LD_W_LEN: |
Patrick McHardy | 3154e54 | 2005-07-05 14:10:40 -0700 | [diff] [blame] | 239 | A = skb->len; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 240 | continue; |
Hagen Paul Pfeifer | 01f2f3f | 2010-06-19 17:05:36 +0000 | [diff] [blame] | 241 | case BPF_S_LDX_W_LEN: |
Patrick McHardy | 3154e54 | 2005-07-05 14:10:40 -0700 | [diff] [blame] | 242 | X = skb->len; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 243 | continue; |
Hagen Paul Pfeifer | 01f2f3f | 2010-06-19 17:05:36 +0000 | [diff] [blame] | 244 | case BPF_S_LD_W_IND: |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 245 | k = X + fentry->k; |
| 246 | goto load_w; |
Hagen Paul Pfeifer | 01f2f3f | 2010-06-19 17:05:36 +0000 | [diff] [blame] | 247 | case BPF_S_LD_H_IND: |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 248 | k = X + fentry->k; |
| 249 | goto load_h; |
Hagen Paul Pfeifer | 01f2f3f | 2010-06-19 17:05:36 +0000 | [diff] [blame] | 250 | case BPF_S_LD_B_IND: |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 251 | k = X + fentry->k; |
| 252 | goto load_b; |
Hagen Paul Pfeifer | 01f2f3f | 2010-06-19 17:05:36 +0000 | [diff] [blame] | 253 | case BPF_S_LDX_B_MSH: |
Patrick McHardy | 0b05b2a | 2005-07-05 14:10:21 -0700 | [diff] [blame] | 254 | ptr = load_pointer(skb, fentry->k, 1, &tmp); |
| 255 | if (ptr != NULL) { |
| 256 | X = (*(u8 *)ptr & 0xf) << 2; |
| 257 | continue; |
| 258 | } |
| 259 | return 0; |
Hagen Paul Pfeifer | 01f2f3f | 2010-06-19 17:05:36 +0000 | [diff] [blame] | 260 | case BPF_S_LD_IMM: |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 261 | A = fentry->k; |
| 262 | continue; |
Hagen Paul Pfeifer | 01f2f3f | 2010-06-19 17:05:36 +0000 | [diff] [blame] | 263 | case BPF_S_LDX_IMM: |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 264 | X = fentry->k; |
| 265 | continue; |
Hagen Paul Pfeifer | 01f2f3f | 2010-06-19 17:05:36 +0000 | [diff] [blame] | 266 | case BPF_S_LD_MEM: |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 267 | A = mem[fentry->k]; |
| 268 | continue; |
Hagen Paul Pfeifer | 01f2f3f | 2010-06-19 17:05:36 +0000 | [diff] [blame] | 269 | case BPF_S_LDX_MEM: |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 270 | X = mem[fentry->k]; |
| 271 | continue; |
Hagen Paul Pfeifer | 01f2f3f | 2010-06-19 17:05:36 +0000 | [diff] [blame] | 272 | case BPF_S_MISC_TAX: |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 273 | X = A; |
| 274 | continue; |
Hagen Paul Pfeifer | 01f2f3f | 2010-06-19 17:05:36 +0000 | [diff] [blame] | 275 | case BPF_S_MISC_TXA: |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 276 | A = X; |
| 277 | continue; |
Hagen Paul Pfeifer | 01f2f3f | 2010-06-19 17:05:36 +0000 | [diff] [blame] | 278 | case BPF_S_RET_K: |
Kris Katterjohn | 4bad4dc | 2006-01-06 13:08:20 -0800 | [diff] [blame] | 279 | return fentry->k; |
Hagen Paul Pfeifer | 01f2f3f | 2010-06-19 17:05:36 +0000 | [diff] [blame] | 280 | case BPF_S_RET_A: |
Kris Katterjohn | 4bad4dc | 2006-01-06 13:08:20 -0800 | [diff] [blame] | 281 | return A; |
Hagen Paul Pfeifer | 01f2f3f | 2010-06-19 17:05:36 +0000 | [diff] [blame] | 282 | case BPF_S_ST: |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 283 | mem[fentry->k] = A; |
| 284 | continue; |
Hagen Paul Pfeifer | 01f2f3f | 2010-06-19 17:05:36 +0000 | [diff] [blame] | 285 | case BPF_S_STX: |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 286 | mem[fentry->k] = X; |
| 287 | continue; |
| 288 | default: |
Kris Katterjohn | 9369986 | 2006-01-04 13:58:36 -0800 | [diff] [blame] | 289 | WARN_ON(1); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 290 | return 0; |
| 291 | } |
| 292 | |
| 293 | /* |
| 294 | * Handle ancillary data, which are impossible |
| 295 | * (or very difficult) to get parsing packet contents. |
| 296 | */ |
| 297 | switch (k-SKF_AD_OFF) { |
| 298 | case SKF_AD_PROTOCOL: |
Al Viro | 252e334 | 2006-11-14 20:48:11 -0800 | [diff] [blame] | 299 | A = ntohs(skb->protocol); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 300 | continue; |
| 301 | case SKF_AD_PKTTYPE: |
| 302 | A = skb->pkt_type; |
| 303 | continue; |
| 304 | case SKF_AD_IFINDEX: |
Paul LeoNerd Evans | 40eaf96 | 2010-04-22 03:32:22 +0000 | [diff] [blame] | 305 | if (!skb->dev) |
| 306 | return 0; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 307 | A = skb->dev->ifindex; |
| 308 | continue; |
jamal | 7e75f93 | 2009-10-19 02:17:56 +0000 | [diff] [blame] | 309 | case SKF_AD_MARK: |
| 310 | A = skb->mark; |
| 311 | continue; |
Eric Dumazet | d19742f | 2009-10-20 01:06:22 -0700 | [diff] [blame] | 312 | case SKF_AD_QUEUE: |
| 313 | A = skb->queue_mapping; |
| 314 | continue; |
Paul LeoNerd Evans | 40eaf96 | 2010-04-22 03:32:22 +0000 | [diff] [blame] | 315 | case SKF_AD_HATYPE: |
| 316 | if (!skb->dev) |
| 317 | return 0; |
| 318 | A = skb->dev->type; |
| 319 | continue; |
Patrick McHardy | 4738c1d | 2008-04-10 02:02:28 -0700 | [diff] [blame] | 320 | case SKF_AD_NLATTR: { |
| 321 | struct nlattr *nla; |
| 322 | |
| 323 | if (skb_is_nonlinear(skb)) |
| 324 | return 0; |
| 325 | if (A > skb->len - sizeof(struct nlattr)) |
| 326 | return 0; |
| 327 | |
| 328 | nla = nla_find((struct nlattr *)&skb->data[A], |
| 329 | skb->len - A, X); |
| 330 | if (nla) |
| 331 | A = (void *)nla - (void *)skb->data; |
| 332 | else |
| 333 | A = 0; |
| 334 | continue; |
| 335 | } |
Pablo Neira Ayuso | d214c75 | 2008-11-20 00:49:27 -0800 | [diff] [blame] | 336 | case SKF_AD_NLATTR_NEST: { |
| 337 | struct nlattr *nla; |
| 338 | |
| 339 | if (skb_is_nonlinear(skb)) |
| 340 | return 0; |
| 341 | if (A > skb->len - sizeof(struct nlattr)) |
| 342 | return 0; |
| 343 | |
| 344 | nla = (struct nlattr *)&skb->data[A]; |
| 345 | if (nla->nla_len > A - skb->len) |
| 346 | return 0; |
| 347 | |
| 348 | nla = nla_find_nested(nla, X); |
| 349 | if (nla) |
| 350 | A = (void *)nla - (void *)skb->data; |
| 351 | else |
| 352 | A = 0; |
| 353 | continue; |
| 354 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 355 | default: |
| 356 | return 0; |
| 357 | } |
| 358 | } |
| 359 | |
| 360 | return 0; |
| 361 | } |
Stephen Hemminger | b715631 | 2008-04-10 01:33:47 -0700 | [diff] [blame] | 362 | EXPORT_SYMBOL(sk_run_filter); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 363 | |
| 364 | /** |
| 365 | * sk_chk_filter - verify socket filter code |
| 366 | * @filter: filter to verify |
| 367 | * @flen: length of filter |
| 368 | * |
| 369 | * Check the user's filter code. If we let some ugly |
| 370 | * filter code slip through kaboom! The filter must contain |
Kris Katterjohn | 9369986 | 2006-01-04 13:58:36 -0800 | [diff] [blame] | 371 | * no references or jumps that are out of range, no illegal |
| 372 | * instructions, and must end with a RET instruction. |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 373 | * |
Kris Katterjohn | 7b11f69 | 2006-01-13 14:33:06 -0800 | [diff] [blame] | 374 | * All jumps are forward as they are not signed. |
| 375 | * |
| 376 | * Returns 0 if the rule set is legal or -EINVAL if not. |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 377 | */ |
| 378 | int sk_chk_filter(struct sock_filter *filter, int flen) |
| 379 | { |
| 380 | struct sock_filter *ftest; |
| 381 | int pc; |
| 382 | |
David S. Miller | 1b93ae64 | 2005-12-27 13:57:59 -0800 | [diff] [blame] | 383 | if (flen == 0 || flen > BPF_MAXINSNS) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 384 | return -EINVAL; |
| 385 | |
| 386 | /* check the filter code now */ |
| 387 | for (pc = 0; pc < flen; pc++) { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 388 | ftest = &filter[pc]; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 389 | |
Kris Katterjohn | 9369986 | 2006-01-04 13:58:36 -0800 | [diff] [blame] | 390 | /* Only allow valid instructions */ |
| 391 | switch (ftest->code) { |
| 392 | case BPF_ALU|BPF_ADD|BPF_K: |
Hagen Paul Pfeifer | 01f2f3f | 2010-06-19 17:05:36 +0000 | [diff] [blame] | 393 | ftest->code = BPF_S_ALU_ADD_K; |
| 394 | break; |
Kris Katterjohn | 9369986 | 2006-01-04 13:58:36 -0800 | [diff] [blame] | 395 | case BPF_ALU|BPF_ADD|BPF_X: |
Hagen Paul Pfeifer | 01f2f3f | 2010-06-19 17:05:36 +0000 | [diff] [blame] | 396 | ftest->code = BPF_S_ALU_ADD_X; |
| 397 | break; |
Kris Katterjohn | 9369986 | 2006-01-04 13:58:36 -0800 | [diff] [blame] | 398 | case BPF_ALU|BPF_SUB|BPF_K: |
Hagen Paul Pfeifer | 01f2f3f | 2010-06-19 17:05:36 +0000 | [diff] [blame] | 399 | ftest->code = BPF_S_ALU_SUB_K; |
| 400 | break; |
Kris Katterjohn | 9369986 | 2006-01-04 13:58:36 -0800 | [diff] [blame] | 401 | case BPF_ALU|BPF_SUB|BPF_X: |
Hagen Paul Pfeifer | 01f2f3f | 2010-06-19 17:05:36 +0000 | [diff] [blame] | 402 | ftest->code = BPF_S_ALU_SUB_X; |
| 403 | break; |
Kris Katterjohn | 9369986 | 2006-01-04 13:58:36 -0800 | [diff] [blame] | 404 | case BPF_ALU|BPF_MUL|BPF_K: |
Hagen Paul Pfeifer | 01f2f3f | 2010-06-19 17:05:36 +0000 | [diff] [blame] | 405 | ftest->code = BPF_S_ALU_MUL_K; |
| 406 | break; |
Kris Katterjohn | 9369986 | 2006-01-04 13:58:36 -0800 | [diff] [blame] | 407 | case BPF_ALU|BPF_MUL|BPF_X: |
Hagen Paul Pfeifer | 01f2f3f | 2010-06-19 17:05:36 +0000 | [diff] [blame] | 408 | ftest->code = BPF_S_ALU_MUL_X; |
| 409 | break; |
Kris Katterjohn | 9369986 | 2006-01-04 13:58:36 -0800 | [diff] [blame] | 410 | case BPF_ALU|BPF_DIV|BPF_X: |
Hagen Paul Pfeifer | 01f2f3f | 2010-06-19 17:05:36 +0000 | [diff] [blame] | 411 | ftest->code = BPF_S_ALU_DIV_X; |
| 412 | break; |
Kris Katterjohn | 9369986 | 2006-01-04 13:58:36 -0800 | [diff] [blame] | 413 | case BPF_ALU|BPF_AND|BPF_K: |
Hagen Paul Pfeifer | 01f2f3f | 2010-06-19 17:05:36 +0000 | [diff] [blame] | 414 | ftest->code = BPF_S_ALU_AND_K; |
| 415 | break; |
Kris Katterjohn | 9369986 | 2006-01-04 13:58:36 -0800 | [diff] [blame] | 416 | case BPF_ALU|BPF_AND|BPF_X: |
Hagen Paul Pfeifer | 01f2f3f | 2010-06-19 17:05:36 +0000 | [diff] [blame] | 417 | ftest->code = BPF_S_ALU_AND_X; |
| 418 | break; |
Kris Katterjohn | 9369986 | 2006-01-04 13:58:36 -0800 | [diff] [blame] | 419 | case BPF_ALU|BPF_OR|BPF_K: |
Hagen Paul Pfeifer | 01f2f3f | 2010-06-19 17:05:36 +0000 | [diff] [blame] | 420 | ftest->code = BPF_S_ALU_OR_K; |
| 421 | break; |
Kris Katterjohn | 9369986 | 2006-01-04 13:58:36 -0800 | [diff] [blame] | 422 | case BPF_ALU|BPF_OR|BPF_X: |
Hagen Paul Pfeifer | 01f2f3f | 2010-06-19 17:05:36 +0000 | [diff] [blame] | 423 | ftest->code = BPF_S_ALU_OR_X; |
| 424 | break; |
Kris Katterjohn | 9369986 | 2006-01-04 13:58:36 -0800 | [diff] [blame] | 425 | case BPF_ALU|BPF_LSH|BPF_K: |
Hagen Paul Pfeifer | 01f2f3f | 2010-06-19 17:05:36 +0000 | [diff] [blame] | 426 | ftest->code = BPF_S_ALU_LSH_K; |
| 427 | break; |
Kris Katterjohn | 9369986 | 2006-01-04 13:58:36 -0800 | [diff] [blame] | 428 | case BPF_ALU|BPF_LSH|BPF_X: |
Hagen Paul Pfeifer | 01f2f3f | 2010-06-19 17:05:36 +0000 | [diff] [blame] | 429 | ftest->code = BPF_S_ALU_LSH_X; |
| 430 | break; |
Kris Katterjohn | 9369986 | 2006-01-04 13:58:36 -0800 | [diff] [blame] | 431 | case BPF_ALU|BPF_RSH|BPF_K: |
Hagen Paul Pfeifer | 01f2f3f | 2010-06-19 17:05:36 +0000 | [diff] [blame] | 432 | ftest->code = BPF_S_ALU_RSH_K; |
| 433 | break; |
Kris Katterjohn | 9369986 | 2006-01-04 13:58:36 -0800 | [diff] [blame] | 434 | case BPF_ALU|BPF_RSH|BPF_X: |
Hagen Paul Pfeifer | 01f2f3f | 2010-06-19 17:05:36 +0000 | [diff] [blame] | 435 | ftest->code = BPF_S_ALU_RSH_X; |
| 436 | break; |
Kris Katterjohn | 9369986 | 2006-01-04 13:58:36 -0800 | [diff] [blame] | 437 | case BPF_ALU|BPF_NEG: |
Hagen Paul Pfeifer | 01f2f3f | 2010-06-19 17:05:36 +0000 | [diff] [blame] | 438 | ftest->code = BPF_S_ALU_NEG; |
| 439 | break; |
Kris Katterjohn | 9369986 | 2006-01-04 13:58:36 -0800 | [diff] [blame] | 440 | case BPF_LD|BPF_W|BPF_ABS: |
Hagen Paul Pfeifer | 01f2f3f | 2010-06-19 17:05:36 +0000 | [diff] [blame] | 441 | ftest->code = BPF_S_LD_W_ABS; |
| 442 | break; |
Kris Katterjohn | 9369986 | 2006-01-04 13:58:36 -0800 | [diff] [blame] | 443 | case BPF_LD|BPF_H|BPF_ABS: |
Hagen Paul Pfeifer | 01f2f3f | 2010-06-19 17:05:36 +0000 | [diff] [blame] | 444 | ftest->code = BPF_S_LD_H_ABS; |
| 445 | break; |
Kris Katterjohn | 9369986 | 2006-01-04 13:58:36 -0800 | [diff] [blame] | 446 | case BPF_LD|BPF_B|BPF_ABS: |
Hagen Paul Pfeifer | 01f2f3f | 2010-06-19 17:05:36 +0000 | [diff] [blame] | 447 | ftest->code = BPF_S_LD_B_ABS; |
| 448 | break; |
Kris Katterjohn | 9369986 | 2006-01-04 13:58:36 -0800 | [diff] [blame] | 449 | case BPF_LD|BPF_W|BPF_LEN: |
Hagen Paul Pfeifer | 01f2f3f | 2010-06-19 17:05:36 +0000 | [diff] [blame] | 450 | ftest->code = BPF_S_LD_W_LEN; |
| 451 | break; |
Kris Katterjohn | 9369986 | 2006-01-04 13:58:36 -0800 | [diff] [blame] | 452 | case BPF_LD|BPF_W|BPF_IND: |
Hagen Paul Pfeifer | 01f2f3f | 2010-06-19 17:05:36 +0000 | [diff] [blame] | 453 | ftest->code = BPF_S_LD_W_IND; |
| 454 | break; |
Kris Katterjohn | 9369986 | 2006-01-04 13:58:36 -0800 | [diff] [blame] | 455 | case BPF_LD|BPF_H|BPF_IND: |
Hagen Paul Pfeifer | 01f2f3f | 2010-06-19 17:05:36 +0000 | [diff] [blame] | 456 | ftest->code = BPF_S_LD_H_IND; |
| 457 | break; |
Kris Katterjohn | 9369986 | 2006-01-04 13:58:36 -0800 | [diff] [blame] | 458 | case BPF_LD|BPF_B|BPF_IND: |
Hagen Paul Pfeifer | 01f2f3f | 2010-06-19 17:05:36 +0000 | [diff] [blame] | 459 | ftest->code = BPF_S_LD_B_IND; |
| 460 | break; |
Kris Katterjohn | 9369986 | 2006-01-04 13:58:36 -0800 | [diff] [blame] | 461 | case BPF_LD|BPF_IMM: |
Hagen Paul Pfeifer | 01f2f3f | 2010-06-19 17:05:36 +0000 | [diff] [blame] | 462 | ftest->code = BPF_S_LD_IMM; |
| 463 | break; |
Kris Katterjohn | 9369986 | 2006-01-04 13:58:36 -0800 | [diff] [blame] | 464 | case BPF_LDX|BPF_W|BPF_LEN: |
Hagen Paul Pfeifer | 01f2f3f | 2010-06-19 17:05:36 +0000 | [diff] [blame] | 465 | ftest->code = BPF_S_LDX_W_LEN; |
| 466 | break; |
Kris Katterjohn | 9369986 | 2006-01-04 13:58:36 -0800 | [diff] [blame] | 467 | case BPF_LDX|BPF_B|BPF_MSH: |
Hagen Paul Pfeifer | 01f2f3f | 2010-06-19 17:05:36 +0000 | [diff] [blame] | 468 | ftest->code = BPF_S_LDX_B_MSH; |
| 469 | break; |
Kris Katterjohn | 9369986 | 2006-01-04 13:58:36 -0800 | [diff] [blame] | 470 | case BPF_LDX|BPF_IMM: |
Hagen Paul Pfeifer | 01f2f3f | 2010-06-19 17:05:36 +0000 | [diff] [blame] | 471 | ftest->code = BPF_S_LDX_IMM; |
| 472 | break; |
Kris Katterjohn | 9369986 | 2006-01-04 13:58:36 -0800 | [diff] [blame] | 473 | case BPF_MISC|BPF_TAX: |
Hagen Paul Pfeifer | 01f2f3f | 2010-06-19 17:05:36 +0000 | [diff] [blame] | 474 | ftest->code = BPF_S_MISC_TAX; |
| 475 | break; |
Kris Katterjohn | 9369986 | 2006-01-04 13:58:36 -0800 | [diff] [blame] | 476 | case BPF_MISC|BPF_TXA: |
Hagen Paul Pfeifer | 01f2f3f | 2010-06-19 17:05:36 +0000 | [diff] [blame] | 477 | ftest->code = BPF_S_MISC_TXA; |
| 478 | break; |
Kris Katterjohn | 9369986 | 2006-01-04 13:58:36 -0800 | [diff] [blame] | 479 | case BPF_RET|BPF_K: |
Hagen Paul Pfeifer | 01f2f3f | 2010-06-19 17:05:36 +0000 | [diff] [blame] | 480 | ftest->code = BPF_S_RET_K; |
| 481 | break; |
Kris Katterjohn | 9369986 | 2006-01-04 13:58:36 -0800 | [diff] [blame] | 482 | case BPF_RET|BPF_A: |
Hagen Paul Pfeifer | 01f2f3f | 2010-06-19 17:05:36 +0000 | [diff] [blame] | 483 | ftest->code = BPF_S_RET_A; |
Kris Katterjohn | 9369986 | 2006-01-04 13:58:36 -0800 | [diff] [blame] | 484 | break; |
Kris Katterjohn | fb0d366 | 2005-11-20 13:41:34 -0800 | [diff] [blame] | 485 | |
Kris Katterjohn | 9369986 | 2006-01-04 13:58:36 -0800 | [diff] [blame] | 486 | /* Some instructions need special checks */ |
| 487 | |
Kris Katterjohn | 9369986 | 2006-01-04 13:58:36 -0800 | [diff] [blame] | 488 | /* check for division by zero */ |
Hagen Paul Pfeifer | 01f2f3f | 2010-06-19 17:05:36 +0000 | [diff] [blame] | 489 | case BPF_ALU|BPF_DIV|BPF_K: |
Kris Katterjohn | 9369986 | 2006-01-04 13:58:36 -0800 | [diff] [blame] | 490 | if (ftest->k == 0) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 491 | return -EINVAL; |
Hagen Paul Pfeifer | 01f2f3f | 2010-06-19 17:05:36 +0000 | [diff] [blame] | 492 | ftest->code = BPF_S_ALU_DIV_K; |
Kris Katterjohn | 9369986 | 2006-01-04 13:58:36 -0800 | [diff] [blame] | 493 | break; |
| 494 | |
Hagen Paul Pfeifer | 01f2f3f | 2010-06-19 17:05:36 +0000 | [diff] [blame] | 495 | /* check for invalid memory addresses */ |
Kris Katterjohn | 9369986 | 2006-01-04 13:58:36 -0800 | [diff] [blame] | 496 | case BPF_LD|BPF_MEM: |
Kris Katterjohn | 9369986 | 2006-01-04 13:58:36 -0800 | [diff] [blame] | 497 | if (ftest->k >= BPF_MEMWORDS) |
| 498 | return -EINVAL; |
Hagen Paul Pfeifer | 01f2f3f | 2010-06-19 17:05:36 +0000 | [diff] [blame] | 499 | ftest->code = BPF_S_LD_MEM; |
| 500 | break; |
| 501 | case BPF_LDX|BPF_MEM: |
| 502 | if (ftest->k >= BPF_MEMWORDS) |
| 503 | return -EINVAL; |
| 504 | ftest->code = BPF_S_LDX_MEM; |
| 505 | break; |
| 506 | case BPF_ST: |
| 507 | if (ftest->k >= BPF_MEMWORDS) |
| 508 | return -EINVAL; |
| 509 | ftest->code = BPF_S_ST; |
| 510 | break; |
| 511 | case BPF_STX: |
| 512 | if (ftest->k >= BPF_MEMWORDS) |
| 513 | return -EINVAL; |
| 514 | ftest->code = BPF_S_STX; |
Kris Katterjohn | 9369986 | 2006-01-04 13:58:36 -0800 | [diff] [blame] | 515 | break; |
| 516 | |
| 517 | case BPF_JMP|BPF_JA: |
| 518 | /* |
| 519 | * Note, the large ftest->k might cause loops. |
| 520 | * Compare this with conditional jumps below, |
| 521 | * where offsets are limited. --ANK (981016) |
| 522 | */ |
| 523 | if (ftest->k >= (unsigned)(flen-pc-1)) |
| 524 | return -EINVAL; |
Hagen Paul Pfeifer | 01f2f3f | 2010-06-19 17:05:36 +0000 | [diff] [blame] | 525 | ftest->code = BPF_S_JMP_JA; |
Kris Katterjohn | 9369986 | 2006-01-04 13:58:36 -0800 | [diff] [blame] | 526 | break; |
| 527 | |
| 528 | case BPF_JMP|BPF_JEQ|BPF_K: |
Hagen Paul Pfeifer | 01f2f3f | 2010-06-19 17:05:36 +0000 | [diff] [blame] | 529 | ftest->code = BPF_S_JMP_JEQ_K; |
| 530 | break; |
Kris Katterjohn | 9369986 | 2006-01-04 13:58:36 -0800 | [diff] [blame] | 531 | case BPF_JMP|BPF_JEQ|BPF_X: |
Hagen Paul Pfeifer | 01f2f3f | 2010-06-19 17:05:36 +0000 | [diff] [blame] | 532 | ftest->code = BPF_S_JMP_JEQ_X; |
| 533 | break; |
Kris Katterjohn | 9369986 | 2006-01-04 13:58:36 -0800 | [diff] [blame] | 534 | case BPF_JMP|BPF_JGE|BPF_K: |
Hagen Paul Pfeifer | 01f2f3f | 2010-06-19 17:05:36 +0000 | [diff] [blame] | 535 | ftest->code = BPF_S_JMP_JGE_K; |
| 536 | break; |
Kris Katterjohn | 9369986 | 2006-01-04 13:58:36 -0800 | [diff] [blame] | 537 | case BPF_JMP|BPF_JGE|BPF_X: |
Hagen Paul Pfeifer | 01f2f3f | 2010-06-19 17:05:36 +0000 | [diff] [blame] | 538 | ftest->code = BPF_S_JMP_JGE_X; |
| 539 | break; |
Kris Katterjohn | 9369986 | 2006-01-04 13:58:36 -0800 | [diff] [blame] | 540 | case BPF_JMP|BPF_JGT|BPF_K: |
Hagen Paul Pfeifer | 01f2f3f | 2010-06-19 17:05:36 +0000 | [diff] [blame] | 541 | ftest->code = BPF_S_JMP_JGT_K; |
| 542 | break; |
Kris Katterjohn | 9369986 | 2006-01-04 13:58:36 -0800 | [diff] [blame] | 543 | case BPF_JMP|BPF_JGT|BPF_X: |
Hagen Paul Pfeifer | 01f2f3f | 2010-06-19 17:05:36 +0000 | [diff] [blame] | 544 | ftest->code = BPF_S_JMP_JGT_X; |
| 545 | break; |
Kris Katterjohn | 9369986 | 2006-01-04 13:58:36 -0800 | [diff] [blame] | 546 | case BPF_JMP|BPF_JSET|BPF_K: |
Hagen Paul Pfeifer | 01f2f3f | 2010-06-19 17:05:36 +0000 | [diff] [blame] | 547 | ftest->code = BPF_S_JMP_JSET_K; |
| 548 | break; |
Kris Katterjohn | 9369986 | 2006-01-04 13:58:36 -0800 | [diff] [blame] | 549 | case BPF_JMP|BPF_JSET|BPF_X: |
Hagen Paul Pfeifer | 01f2f3f | 2010-06-19 17:05:36 +0000 | [diff] [blame] | 550 | ftest->code = BPF_S_JMP_JSET_X; |
Kris Katterjohn | 9369986 | 2006-01-04 13:58:36 -0800 | [diff] [blame] | 551 | break; |
| 552 | |
| 553 | default: |
| 554 | return -EINVAL; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 555 | } |
Hagen Paul Pfeifer | 01f2f3f | 2010-06-19 17:05:36 +0000 | [diff] [blame] | 556 | |
| 557 | /* for conditionals both must be safe */ |
| 558 | switch (ftest->code) { |
| 559 | case BPF_S_JMP_JEQ_K: |
| 560 | case BPF_S_JMP_JEQ_X: |
| 561 | case BPF_S_JMP_JGE_K: |
| 562 | case BPF_S_JMP_JGE_X: |
| 563 | case BPF_S_JMP_JGT_K: |
| 564 | case BPF_S_JMP_JGT_X: |
| 565 | case BPF_S_JMP_JSET_X: |
| 566 | case BPF_S_JMP_JSET_K: |
| 567 | if (pc + ftest->jt + 1 >= flen || |
| 568 | pc + ftest->jf + 1 >= flen) |
| 569 | return -EINVAL; |
| 570 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 571 | } |
| 572 | |
Hagen Paul Pfeifer | 01f2f3f | 2010-06-19 17:05:36 +0000 | [diff] [blame] | 573 | /* last instruction must be a RET code */ |
| 574 | switch (filter[flen - 1].code) { |
| 575 | case BPF_S_RET_K: |
| 576 | case BPF_S_RET_A: |
| 577 | return 0; |
| 578 | break; |
| 579 | default: |
| 580 | return -EINVAL; |
| 581 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 582 | } |
Stephen Hemminger | b715631 | 2008-04-10 01:33:47 -0700 | [diff] [blame] | 583 | EXPORT_SYMBOL(sk_chk_filter); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 584 | |
| 585 | /** |
Pavel Emelyanov | 47e958e | 2007-10-17 21:22:42 -0700 | [diff] [blame] | 586 | * sk_filter_rcu_release: Release a socket filter by rcu_head |
| 587 | * @rcu: rcu_head that contains the sk_filter to free |
| 588 | */ |
| 589 | static void sk_filter_rcu_release(struct rcu_head *rcu) |
| 590 | { |
| 591 | struct sk_filter *fp = container_of(rcu, struct sk_filter, rcu); |
| 592 | |
| 593 | sk_filter_release(fp); |
| 594 | } |
| 595 | |
| 596 | static void sk_filter_delayed_uncharge(struct sock *sk, struct sk_filter *fp) |
| 597 | { |
| 598 | unsigned int size = sk_filter_len(fp); |
| 599 | |
| 600 | atomic_sub(size, &sk->sk_omem_alloc); |
| 601 | call_rcu_bh(&fp->rcu, sk_filter_rcu_release); |
| 602 | } |
| 603 | |
| 604 | /** |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 605 | * sk_attach_filter - attach a socket filter |
| 606 | * @fprog: the filter program |
| 607 | * @sk: the socket to use |
| 608 | * |
| 609 | * Attach the user's filter code. We first run some sanity checks on |
| 610 | * it to make sure it does not explode on us later. If an error |
| 611 | * occurs or there is insufficient memory for the filter a negative |
| 612 | * errno code is returned. On success the return is zero. |
| 613 | */ |
| 614 | int sk_attach_filter(struct sock_fprog *fprog, struct sock *sk) |
| 615 | { |
Pavel Emelyanov | d3904b7 | 2007-10-17 21:22:17 -0700 | [diff] [blame] | 616 | struct sk_filter *fp, *old_fp; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 617 | unsigned int fsize = sizeof(struct sock_filter) * fprog->len; |
| 618 | int err; |
| 619 | |
| 620 | /* Make sure new filter is there and in the right amounts. */ |
Kris Katterjohn | e35bedf | 2006-01-17 02:25:52 -0800 | [diff] [blame] | 621 | if (fprog->filter == NULL) |
| 622 | return -EINVAL; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 623 | |
| 624 | fp = sock_kmalloc(sk, fsize+sizeof(*fp), GFP_KERNEL); |
| 625 | if (!fp) |
| 626 | return -ENOMEM; |
| 627 | if (copy_from_user(fp->insns, fprog->filter, fsize)) { |
YOSHIFUJI Hideaki | 4ec93ed | 2007-02-09 23:24:36 +0900 | [diff] [blame] | 628 | sock_kfree_s(sk, fp, fsize+sizeof(*fp)); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 629 | return -EFAULT; |
| 630 | } |
| 631 | |
| 632 | atomic_set(&fp->refcnt, 1); |
| 633 | fp->len = fprog->len; |
| 634 | |
| 635 | err = sk_chk_filter(fp->insns, fp->len); |
Pavel Emelyanov | d3904b7 | 2007-10-17 21:22:17 -0700 | [diff] [blame] | 636 | if (err) { |
| 637 | sk_filter_uncharge(sk, fp); |
| 638 | return err; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 639 | } |
| 640 | |
Eric Dumazet | f91ff5b | 2010-09-27 06:07:30 +0000 | [diff] [blame] | 641 | old_fp = rcu_dereference_protected(sk->sk_filter, |
| 642 | sock_owned_by_user(sk)); |
Pavel Emelyanov | d3904b7 | 2007-10-17 21:22:17 -0700 | [diff] [blame] | 643 | rcu_assign_pointer(sk->sk_filter, fp); |
Pavel Emelyanov | d3904b7 | 2007-10-17 21:22:17 -0700 | [diff] [blame] | 644 | |
Olof Johansson | 9b013e0 | 2007-10-18 21:48:39 -0700 | [diff] [blame] | 645 | if (old_fp) |
| 646 | sk_filter_delayed_uncharge(sk, old_fp); |
Pavel Emelyanov | d3904b7 | 2007-10-17 21:22:17 -0700 | [diff] [blame] | 647 | return 0; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 648 | } |
Michael S. Tsirkin | 5ff3f07 | 2010-02-14 01:01:00 +0000 | [diff] [blame] | 649 | EXPORT_SYMBOL_GPL(sk_attach_filter); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 650 | |
Pavel Emelyanov | 55b3332 | 2007-10-17 21:21:26 -0700 | [diff] [blame] | 651 | int sk_detach_filter(struct sock *sk) |
| 652 | { |
| 653 | int ret = -ENOENT; |
| 654 | struct sk_filter *filter; |
| 655 | |
Eric Dumazet | f91ff5b | 2010-09-27 06:07:30 +0000 | [diff] [blame] | 656 | filter = rcu_dereference_protected(sk->sk_filter, |
| 657 | sock_owned_by_user(sk)); |
Pavel Emelyanov | 55b3332 | 2007-10-17 21:21:26 -0700 | [diff] [blame] | 658 | if (filter) { |
| 659 | rcu_assign_pointer(sk->sk_filter, NULL); |
Pavel Emelyanov | 47e958e | 2007-10-17 21:22:42 -0700 | [diff] [blame] | 660 | sk_filter_delayed_uncharge(sk, filter); |
Pavel Emelyanov | 55b3332 | 2007-10-17 21:21:26 -0700 | [diff] [blame] | 661 | ret = 0; |
| 662 | } |
Pavel Emelyanov | 55b3332 | 2007-10-17 21:21:26 -0700 | [diff] [blame] | 663 | return ret; |
| 664 | } |
Michael S. Tsirkin | 5ff3f07 | 2010-02-14 01:01:00 +0000 | [diff] [blame] | 665 | EXPORT_SYMBOL_GPL(sk_detach_filter); |