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) { |
Eric Dumazet | 0d7da9d | 2010-10-25 03:47:05 +0000 | [diff] [blame] | 92 | unsigned int pkt_len = sk_run_filter(skb, filter->insns, filter->len); |
| 93 | |
Stephen Hemminger | 43db6d6 | 2008-04-10 01:43:09 -0700 | [diff] [blame] | 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 | { |
Patrick McHardy | 0b05b2a | 2005-07-05 14:10:21 -0700 | [diff] [blame] | 115 | void *ptr; |
Kris Katterjohn | 2966b66 | 2006-01-23 16:26:16 -0800 | [diff] [blame] | 116 | u32 A = 0; /* Accumulator */ |
| 117 | u32 X = 0; /* Index Register */ |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 118 | u32 mem[BPF_MEMWORDS]; /* Scratch Memory Store */ |
David S. Miller | 57fe93b | 2010-11-10 10:38:24 -0800 | [diff] [blame] | 119 | unsigned long memvalid = 0; |
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 | |
David S. Miller | 57fe93b | 2010-11-10 10:38:24 -0800 | [diff] [blame] | 124 | BUILD_BUG_ON(BPF_MEMWORDS > BITS_PER_LONG); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 125 | /* |
| 126 | * Process array of filter instructions. |
| 127 | */ |
| 128 | for (pc = 0; pc < flen; pc++) { |
David S. Miller | 57fe93b | 2010-11-10 10:38:24 -0800 | [diff] [blame] | 129 | const struct sock_filter *fentry = &filter[pc]; |
| 130 | u32 f_k = fentry->k; |
YOSHIFUJI Hideaki | 4ec93ed | 2007-02-09 23:24:36 +0900 | [diff] [blame] | 131 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 132 | switch (fentry->code) { |
Hagen Paul Pfeifer | 01f2f3f | 2010-06-19 17:05:36 +0000 | [diff] [blame] | 133 | case BPF_S_ALU_ADD_X: |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 134 | A += X; |
| 135 | continue; |
Hagen Paul Pfeifer | 01f2f3f | 2010-06-19 17:05:36 +0000 | [diff] [blame] | 136 | case BPF_S_ALU_ADD_K: |
David S. Miller | 57fe93b | 2010-11-10 10:38:24 -0800 | [diff] [blame] | 137 | A += f_k; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 138 | continue; |
Hagen Paul Pfeifer | 01f2f3f | 2010-06-19 17:05:36 +0000 | [diff] [blame] | 139 | case BPF_S_ALU_SUB_X: |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 140 | A -= X; |
| 141 | continue; |
Hagen Paul Pfeifer | 01f2f3f | 2010-06-19 17:05:36 +0000 | [diff] [blame] | 142 | case BPF_S_ALU_SUB_K: |
David S. Miller | 57fe93b | 2010-11-10 10:38:24 -0800 | [diff] [blame] | 143 | A -= f_k; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 144 | continue; |
Hagen Paul Pfeifer | 01f2f3f | 2010-06-19 17:05:36 +0000 | [diff] [blame] | 145 | case BPF_S_ALU_MUL_X: |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 146 | A *= X; |
| 147 | continue; |
Hagen Paul Pfeifer | 01f2f3f | 2010-06-19 17:05:36 +0000 | [diff] [blame] | 148 | case BPF_S_ALU_MUL_K: |
David S. Miller | 57fe93b | 2010-11-10 10:38:24 -0800 | [diff] [blame] | 149 | A *= f_k; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 150 | continue; |
Hagen Paul Pfeifer | 01f2f3f | 2010-06-19 17:05:36 +0000 | [diff] [blame] | 151 | case BPF_S_ALU_DIV_X: |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 152 | if (X == 0) |
| 153 | return 0; |
| 154 | A /= X; |
| 155 | continue; |
Hagen Paul Pfeifer | 01f2f3f | 2010-06-19 17:05:36 +0000 | [diff] [blame] | 156 | case BPF_S_ALU_DIV_K: |
David S. Miller | 57fe93b | 2010-11-10 10:38:24 -0800 | [diff] [blame] | 157 | A /= f_k; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 158 | continue; |
Hagen Paul Pfeifer | 01f2f3f | 2010-06-19 17:05:36 +0000 | [diff] [blame] | 159 | case BPF_S_ALU_AND_X: |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 160 | A &= X; |
| 161 | continue; |
Hagen Paul Pfeifer | 01f2f3f | 2010-06-19 17:05:36 +0000 | [diff] [blame] | 162 | case BPF_S_ALU_AND_K: |
David S. Miller | 57fe93b | 2010-11-10 10:38:24 -0800 | [diff] [blame] | 163 | A &= f_k; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 164 | continue; |
Hagen Paul Pfeifer | 01f2f3f | 2010-06-19 17:05:36 +0000 | [diff] [blame] | 165 | case BPF_S_ALU_OR_X: |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 166 | A |= X; |
| 167 | continue; |
Hagen Paul Pfeifer | 01f2f3f | 2010-06-19 17:05:36 +0000 | [diff] [blame] | 168 | case BPF_S_ALU_OR_K: |
David S. Miller | 57fe93b | 2010-11-10 10:38:24 -0800 | [diff] [blame] | 169 | A |= f_k; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 170 | continue; |
Hagen Paul Pfeifer | 01f2f3f | 2010-06-19 17:05:36 +0000 | [diff] [blame] | 171 | case BPF_S_ALU_LSH_X: |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 172 | A <<= X; |
| 173 | continue; |
Hagen Paul Pfeifer | 01f2f3f | 2010-06-19 17:05:36 +0000 | [diff] [blame] | 174 | case BPF_S_ALU_LSH_K: |
David S. Miller | 57fe93b | 2010-11-10 10:38:24 -0800 | [diff] [blame] | 175 | A <<= f_k; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 176 | continue; |
Hagen Paul Pfeifer | 01f2f3f | 2010-06-19 17:05:36 +0000 | [diff] [blame] | 177 | case BPF_S_ALU_RSH_X: |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 178 | A >>= X; |
| 179 | continue; |
Hagen Paul Pfeifer | 01f2f3f | 2010-06-19 17:05:36 +0000 | [diff] [blame] | 180 | case BPF_S_ALU_RSH_K: |
David S. Miller | 57fe93b | 2010-11-10 10:38:24 -0800 | [diff] [blame] | 181 | A >>= f_k; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 182 | continue; |
Hagen Paul Pfeifer | 01f2f3f | 2010-06-19 17:05:36 +0000 | [diff] [blame] | 183 | case BPF_S_ALU_NEG: |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 184 | A = -A; |
| 185 | continue; |
Hagen Paul Pfeifer | 01f2f3f | 2010-06-19 17:05:36 +0000 | [diff] [blame] | 186 | case BPF_S_JMP_JA: |
David S. Miller | 57fe93b | 2010-11-10 10:38:24 -0800 | [diff] [blame] | 187 | pc += f_k; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 188 | continue; |
Hagen Paul Pfeifer | 01f2f3f | 2010-06-19 17:05:36 +0000 | [diff] [blame] | 189 | case BPF_S_JMP_JGT_K: |
David S. Miller | 57fe93b | 2010-11-10 10:38:24 -0800 | [diff] [blame] | 190 | pc += (A > f_k) ? fentry->jt : fentry->jf; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 191 | continue; |
Hagen Paul Pfeifer | 01f2f3f | 2010-06-19 17:05:36 +0000 | [diff] [blame] | 192 | case BPF_S_JMP_JGE_K: |
David S. Miller | 57fe93b | 2010-11-10 10:38:24 -0800 | [diff] [blame] | 193 | pc += (A >= f_k) ? fentry->jt : fentry->jf; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 194 | continue; |
Hagen Paul Pfeifer | 01f2f3f | 2010-06-19 17:05:36 +0000 | [diff] [blame] | 195 | case BPF_S_JMP_JEQ_K: |
David S. Miller | 57fe93b | 2010-11-10 10:38:24 -0800 | [diff] [blame] | 196 | pc += (A == f_k) ? fentry->jt : fentry->jf; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 197 | continue; |
Hagen Paul Pfeifer | 01f2f3f | 2010-06-19 17:05:36 +0000 | [diff] [blame] | 198 | case BPF_S_JMP_JSET_K: |
David S. Miller | 57fe93b | 2010-11-10 10:38:24 -0800 | [diff] [blame] | 199 | pc += (A & f_k) ? fentry->jt : fentry->jf; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 200 | continue; |
Hagen Paul Pfeifer | 01f2f3f | 2010-06-19 17:05:36 +0000 | [diff] [blame] | 201 | case BPF_S_JMP_JGT_X: |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 202 | pc += (A > X) ? fentry->jt : fentry->jf; |
| 203 | continue; |
Hagen Paul Pfeifer | 01f2f3f | 2010-06-19 17:05:36 +0000 | [diff] [blame] | 204 | case BPF_S_JMP_JGE_X: |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 205 | pc += (A >= X) ? fentry->jt : fentry->jf; |
| 206 | continue; |
Hagen Paul Pfeifer | 01f2f3f | 2010-06-19 17:05:36 +0000 | [diff] [blame] | 207 | case BPF_S_JMP_JEQ_X: |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 208 | pc += (A == X) ? fentry->jt : fentry->jf; |
| 209 | continue; |
Hagen Paul Pfeifer | 01f2f3f | 2010-06-19 17:05:36 +0000 | [diff] [blame] | 210 | case BPF_S_JMP_JSET_X: |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 211 | pc += (A & X) ? fentry->jt : fentry->jf; |
| 212 | continue; |
Hagen Paul Pfeifer | 01f2f3f | 2010-06-19 17:05:36 +0000 | [diff] [blame] | 213 | case BPF_S_LD_W_ABS: |
David S. Miller | 57fe93b | 2010-11-10 10:38:24 -0800 | [diff] [blame] | 214 | k = f_k; |
Kris Katterjohn | e35bedf | 2006-01-17 02:25:52 -0800 | [diff] [blame] | 215 | load_w: |
Patrick McHardy | 0b05b2a | 2005-07-05 14:10:21 -0700 | [diff] [blame] | 216 | ptr = load_pointer(skb, k, 4, &tmp); |
| 217 | if (ptr != NULL) { |
Harvey Harrison | d3e2ce3 | 2008-05-02 16:26:16 -0700 | [diff] [blame] | 218 | A = get_unaligned_be32(ptr); |
Patrick McHardy | 0b05b2a | 2005-07-05 14:10:21 -0700 | [diff] [blame] | 219 | continue; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 220 | } |
Herbert Xu | 1198ad0 | 2005-09-05 18:44:37 -0700 | [diff] [blame] | 221 | break; |
Hagen Paul Pfeifer | 01f2f3f | 2010-06-19 17:05:36 +0000 | [diff] [blame] | 222 | case BPF_S_LD_H_ABS: |
David S. Miller | 57fe93b | 2010-11-10 10:38:24 -0800 | [diff] [blame] | 223 | k = f_k; |
Kris Katterjohn | e35bedf | 2006-01-17 02:25:52 -0800 | [diff] [blame] | 224 | load_h: |
Patrick McHardy | 0b05b2a | 2005-07-05 14:10:21 -0700 | [diff] [blame] | 225 | ptr = load_pointer(skb, k, 2, &tmp); |
| 226 | if (ptr != NULL) { |
Harvey Harrison | d3e2ce3 | 2008-05-02 16:26:16 -0700 | [diff] [blame] | 227 | A = get_unaligned_be16(ptr); |
Patrick McHardy | 0b05b2a | 2005-07-05 14:10:21 -0700 | [diff] [blame] | 228 | continue; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 229 | } |
Herbert Xu | 1198ad0 | 2005-09-05 18:44:37 -0700 | [diff] [blame] | 230 | break; |
Hagen Paul Pfeifer | 01f2f3f | 2010-06-19 17:05:36 +0000 | [diff] [blame] | 231 | case BPF_S_LD_B_ABS: |
David S. Miller | 57fe93b | 2010-11-10 10:38:24 -0800 | [diff] [blame] | 232 | k = f_k; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 233 | load_b: |
Patrick McHardy | 0b05b2a | 2005-07-05 14:10:21 -0700 | [diff] [blame] | 234 | ptr = load_pointer(skb, k, 1, &tmp); |
| 235 | if (ptr != NULL) { |
| 236 | A = *(u8 *)ptr; |
| 237 | continue; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 238 | } |
Herbert Xu | 1198ad0 | 2005-09-05 18:44:37 -0700 | [diff] [blame] | 239 | break; |
Hagen Paul Pfeifer | 01f2f3f | 2010-06-19 17:05:36 +0000 | [diff] [blame] | 240 | case BPF_S_LD_W_LEN: |
Patrick McHardy | 3154e54 | 2005-07-05 14:10:40 -0700 | [diff] [blame] | 241 | A = skb->len; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 242 | continue; |
Hagen Paul Pfeifer | 01f2f3f | 2010-06-19 17:05:36 +0000 | [diff] [blame] | 243 | case BPF_S_LDX_W_LEN: |
Patrick McHardy | 3154e54 | 2005-07-05 14:10:40 -0700 | [diff] [blame] | 244 | X = skb->len; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 245 | continue; |
Hagen Paul Pfeifer | 01f2f3f | 2010-06-19 17:05:36 +0000 | [diff] [blame] | 246 | case BPF_S_LD_W_IND: |
David S. Miller | 57fe93b | 2010-11-10 10:38:24 -0800 | [diff] [blame] | 247 | k = X + f_k; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 248 | goto load_w; |
Hagen Paul Pfeifer | 01f2f3f | 2010-06-19 17:05:36 +0000 | [diff] [blame] | 249 | case BPF_S_LD_H_IND: |
David S. Miller | 57fe93b | 2010-11-10 10:38:24 -0800 | [diff] [blame] | 250 | k = X + f_k; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 251 | goto load_h; |
Hagen Paul Pfeifer | 01f2f3f | 2010-06-19 17:05:36 +0000 | [diff] [blame] | 252 | case BPF_S_LD_B_IND: |
David S. Miller | 57fe93b | 2010-11-10 10:38:24 -0800 | [diff] [blame] | 253 | k = X + f_k; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 254 | goto load_b; |
Hagen Paul Pfeifer | 01f2f3f | 2010-06-19 17:05:36 +0000 | [diff] [blame] | 255 | case BPF_S_LDX_B_MSH: |
David S. Miller | 57fe93b | 2010-11-10 10:38:24 -0800 | [diff] [blame] | 256 | ptr = load_pointer(skb, f_k, 1, &tmp); |
Patrick McHardy | 0b05b2a | 2005-07-05 14:10:21 -0700 | [diff] [blame] | 257 | if (ptr != NULL) { |
| 258 | X = (*(u8 *)ptr & 0xf) << 2; |
| 259 | continue; |
| 260 | } |
| 261 | return 0; |
Hagen Paul Pfeifer | 01f2f3f | 2010-06-19 17:05:36 +0000 | [diff] [blame] | 262 | case BPF_S_LD_IMM: |
David S. Miller | 57fe93b | 2010-11-10 10:38:24 -0800 | [diff] [blame] | 263 | A = f_k; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 264 | continue; |
Hagen Paul Pfeifer | 01f2f3f | 2010-06-19 17:05:36 +0000 | [diff] [blame] | 265 | case BPF_S_LDX_IMM: |
David S. Miller | 57fe93b | 2010-11-10 10:38:24 -0800 | [diff] [blame] | 266 | X = f_k; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 267 | continue; |
Hagen Paul Pfeifer | 01f2f3f | 2010-06-19 17:05:36 +0000 | [diff] [blame] | 268 | case BPF_S_LD_MEM: |
David S. Miller | 57fe93b | 2010-11-10 10:38:24 -0800 | [diff] [blame] | 269 | A = (memvalid & (1UL << f_k)) ? |
| 270 | mem[f_k] : 0; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 271 | continue; |
Hagen Paul Pfeifer | 01f2f3f | 2010-06-19 17:05:36 +0000 | [diff] [blame] | 272 | case BPF_S_LDX_MEM: |
David S. Miller | 57fe93b | 2010-11-10 10:38:24 -0800 | [diff] [blame] | 273 | X = (memvalid & (1UL << f_k)) ? |
| 274 | mem[f_k] : 0; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 275 | continue; |
Hagen Paul Pfeifer | 01f2f3f | 2010-06-19 17:05:36 +0000 | [diff] [blame] | 276 | case BPF_S_MISC_TAX: |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 277 | X = A; |
| 278 | continue; |
Hagen Paul Pfeifer | 01f2f3f | 2010-06-19 17:05:36 +0000 | [diff] [blame] | 279 | case BPF_S_MISC_TXA: |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 280 | A = X; |
| 281 | continue; |
Hagen Paul Pfeifer | 01f2f3f | 2010-06-19 17:05:36 +0000 | [diff] [blame] | 282 | case BPF_S_RET_K: |
David S. Miller | 57fe93b | 2010-11-10 10:38:24 -0800 | [diff] [blame] | 283 | return f_k; |
Hagen Paul Pfeifer | 01f2f3f | 2010-06-19 17:05:36 +0000 | [diff] [blame] | 284 | case BPF_S_RET_A: |
Kris Katterjohn | 4bad4dc | 2006-01-06 13:08:20 -0800 | [diff] [blame] | 285 | return A; |
Hagen Paul Pfeifer | 01f2f3f | 2010-06-19 17:05:36 +0000 | [diff] [blame] | 286 | case BPF_S_ST: |
David S. Miller | 57fe93b | 2010-11-10 10:38:24 -0800 | [diff] [blame] | 287 | memvalid |= 1UL << f_k; |
| 288 | mem[f_k] = A; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 289 | continue; |
Hagen Paul Pfeifer | 01f2f3f | 2010-06-19 17:05:36 +0000 | [diff] [blame] | 290 | case BPF_S_STX: |
David S. Miller | 57fe93b | 2010-11-10 10:38:24 -0800 | [diff] [blame] | 291 | memvalid |= 1UL << f_k; |
| 292 | mem[f_k] = X; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 293 | continue; |
| 294 | default: |
Kris Katterjohn | 9369986 | 2006-01-04 13:58:36 -0800 | [diff] [blame] | 295 | WARN_ON(1); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 296 | return 0; |
| 297 | } |
| 298 | |
| 299 | /* |
| 300 | * Handle ancillary data, which are impossible |
| 301 | * (or very difficult) to get parsing packet contents. |
| 302 | */ |
| 303 | switch (k-SKF_AD_OFF) { |
| 304 | case SKF_AD_PROTOCOL: |
Al Viro | 252e334 | 2006-11-14 20:48:11 -0800 | [diff] [blame] | 305 | A = ntohs(skb->protocol); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 306 | continue; |
| 307 | case SKF_AD_PKTTYPE: |
| 308 | A = skb->pkt_type; |
| 309 | continue; |
| 310 | case SKF_AD_IFINDEX: |
Paul LeoNerd Evans | 40eaf96 | 2010-04-22 03:32:22 +0000 | [diff] [blame] | 311 | if (!skb->dev) |
| 312 | return 0; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 313 | A = skb->dev->ifindex; |
| 314 | continue; |
jamal | 7e75f93 | 2009-10-19 02:17:56 +0000 | [diff] [blame] | 315 | case SKF_AD_MARK: |
| 316 | A = skb->mark; |
| 317 | continue; |
Eric Dumazet | d19742f | 2009-10-20 01:06:22 -0700 | [diff] [blame] | 318 | case SKF_AD_QUEUE: |
| 319 | A = skb->queue_mapping; |
| 320 | continue; |
Paul LeoNerd Evans | 40eaf96 | 2010-04-22 03:32:22 +0000 | [diff] [blame] | 321 | case SKF_AD_HATYPE: |
| 322 | if (!skb->dev) |
| 323 | return 0; |
| 324 | A = skb->dev->type; |
| 325 | continue; |
Patrick McHardy | 4738c1d | 2008-04-10 02:02:28 -0700 | [diff] [blame] | 326 | case SKF_AD_NLATTR: { |
| 327 | struct nlattr *nla; |
| 328 | |
| 329 | if (skb_is_nonlinear(skb)) |
| 330 | return 0; |
| 331 | if (A > skb->len - sizeof(struct nlattr)) |
| 332 | return 0; |
| 333 | |
| 334 | nla = nla_find((struct nlattr *)&skb->data[A], |
| 335 | skb->len - A, X); |
| 336 | if (nla) |
| 337 | A = (void *)nla - (void *)skb->data; |
| 338 | else |
| 339 | A = 0; |
| 340 | continue; |
| 341 | } |
Pablo Neira Ayuso | d214c75 | 2008-11-20 00:49:27 -0800 | [diff] [blame] | 342 | case SKF_AD_NLATTR_NEST: { |
| 343 | struct nlattr *nla; |
| 344 | |
| 345 | if (skb_is_nonlinear(skb)) |
| 346 | return 0; |
| 347 | if (A > skb->len - sizeof(struct nlattr)) |
| 348 | return 0; |
| 349 | |
| 350 | nla = (struct nlattr *)&skb->data[A]; |
| 351 | if (nla->nla_len > A - skb->len) |
| 352 | return 0; |
| 353 | |
| 354 | nla = nla_find_nested(nla, X); |
| 355 | if (nla) |
| 356 | A = (void *)nla - (void *)skb->data; |
| 357 | else |
| 358 | A = 0; |
| 359 | continue; |
| 360 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 361 | default: |
| 362 | return 0; |
| 363 | } |
| 364 | } |
| 365 | |
| 366 | return 0; |
| 367 | } |
Stephen Hemminger | b715631 | 2008-04-10 01:33:47 -0700 | [diff] [blame] | 368 | EXPORT_SYMBOL(sk_run_filter); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 369 | |
| 370 | /** |
| 371 | * sk_chk_filter - verify socket filter code |
| 372 | * @filter: filter to verify |
| 373 | * @flen: length of filter |
| 374 | * |
| 375 | * Check the user's filter code. If we let some ugly |
| 376 | * filter code slip through kaboom! The filter must contain |
Kris Katterjohn | 9369986 | 2006-01-04 13:58:36 -0800 | [diff] [blame] | 377 | * no references or jumps that are out of range, no illegal |
| 378 | * instructions, and must end with a RET instruction. |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 379 | * |
Kris Katterjohn | 7b11f69 | 2006-01-13 14:33:06 -0800 | [diff] [blame] | 380 | * All jumps are forward as they are not signed. |
| 381 | * |
| 382 | * Returns 0 if the rule set is legal or -EINVAL if not. |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 383 | */ |
| 384 | int sk_chk_filter(struct sock_filter *filter, int flen) |
| 385 | { |
| 386 | struct sock_filter *ftest; |
| 387 | int pc; |
| 388 | |
David S. Miller | 1b93ae64 | 2005-12-27 13:57:59 -0800 | [diff] [blame] | 389 | if (flen == 0 || flen > BPF_MAXINSNS) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 390 | return -EINVAL; |
| 391 | |
| 392 | /* check the filter code now */ |
| 393 | for (pc = 0; pc < flen; pc++) { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 394 | ftest = &filter[pc]; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 395 | |
Kris Katterjohn | 9369986 | 2006-01-04 13:58:36 -0800 | [diff] [blame] | 396 | /* Only allow valid instructions */ |
| 397 | switch (ftest->code) { |
| 398 | case BPF_ALU|BPF_ADD|BPF_K: |
Hagen Paul Pfeifer | 01f2f3f | 2010-06-19 17:05:36 +0000 | [diff] [blame] | 399 | ftest->code = BPF_S_ALU_ADD_K; |
| 400 | break; |
Kris Katterjohn | 9369986 | 2006-01-04 13:58:36 -0800 | [diff] [blame] | 401 | case BPF_ALU|BPF_ADD|BPF_X: |
Hagen Paul Pfeifer | 01f2f3f | 2010-06-19 17:05:36 +0000 | [diff] [blame] | 402 | ftest->code = BPF_S_ALU_ADD_X; |
| 403 | break; |
Kris Katterjohn | 9369986 | 2006-01-04 13:58:36 -0800 | [diff] [blame] | 404 | case BPF_ALU|BPF_SUB|BPF_K: |
Hagen Paul Pfeifer | 01f2f3f | 2010-06-19 17:05:36 +0000 | [diff] [blame] | 405 | ftest->code = BPF_S_ALU_SUB_K; |
| 406 | break; |
Kris Katterjohn | 9369986 | 2006-01-04 13:58:36 -0800 | [diff] [blame] | 407 | case BPF_ALU|BPF_SUB|BPF_X: |
Hagen Paul Pfeifer | 01f2f3f | 2010-06-19 17:05:36 +0000 | [diff] [blame] | 408 | ftest->code = BPF_S_ALU_SUB_X; |
| 409 | break; |
Kris Katterjohn | 9369986 | 2006-01-04 13:58:36 -0800 | [diff] [blame] | 410 | case BPF_ALU|BPF_MUL|BPF_K: |
Hagen Paul Pfeifer | 01f2f3f | 2010-06-19 17:05:36 +0000 | [diff] [blame] | 411 | ftest->code = BPF_S_ALU_MUL_K; |
| 412 | break; |
Kris Katterjohn | 9369986 | 2006-01-04 13:58:36 -0800 | [diff] [blame] | 413 | case BPF_ALU|BPF_MUL|BPF_X: |
Hagen Paul Pfeifer | 01f2f3f | 2010-06-19 17:05:36 +0000 | [diff] [blame] | 414 | ftest->code = BPF_S_ALU_MUL_X; |
| 415 | break; |
Kris Katterjohn | 9369986 | 2006-01-04 13:58:36 -0800 | [diff] [blame] | 416 | case BPF_ALU|BPF_DIV|BPF_X: |
Hagen Paul Pfeifer | 01f2f3f | 2010-06-19 17:05:36 +0000 | [diff] [blame] | 417 | ftest->code = BPF_S_ALU_DIV_X; |
| 418 | break; |
Kris Katterjohn | 9369986 | 2006-01-04 13:58:36 -0800 | [diff] [blame] | 419 | case BPF_ALU|BPF_AND|BPF_K: |
Hagen Paul Pfeifer | 01f2f3f | 2010-06-19 17:05:36 +0000 | [diff] [blame] | 420 | ftest->code = BPF_S_ALU_AND_K; |
| 421 | break; |
Kris Katterjohn | 9369986 | 2006-01-04 13:58:36 -0800 | [diff] [blame] | 422 | case BPF_ALU|BPF_AND|BPF_X: |
Hagen Paul Pfeifer | 01f2f3f | 2010-06-19 17:05:36 +0000 | [diff] [blame] | 423 | ftest->code = BPF_S_ALU_AND_X; |
| 424 | break; |
Kris Katterjohn | 9369986 | 2006-01-04 13:58:36 -0800 | [diff] [blame] | 425 | case BPF_ALU|BPF_OR|BPF_K: |
Hagen Paul Pfeifer | 01f2f3f | 2010-06-19 17:05:36 +0000 | [diff] [blame] | 426 | ftest->code = BPF_S_ALU_OR_K; |
| 427 | break; |
Kris Katterjohn | 9369986 | 2006-01-04 13:58:36 -0800 | [diff] [blame] | 428 | case BPF_ALU|BPF_OR|BPF_X: |
Hagen Paul Pfeifer | 01f2f3f | 2010-06-19 17:05:36 +0000 | [diff] [blame] | 429 | ftest->code = BPF_S_ALU_OR_X; |
| 430 | break; |
Kris Katterjohn | 9369986 | 2006-01-04 13:58:36 -0800 | [diff] [blame] | 431 | case BPF_ALU|BPF_LSH|BPF_K: |
Hagen Paul Pfeifer | 01f2f3f | 2010-06-19 17:05:36 +0000 | [diff] [blame] | 432 | ftest->code = BPF_S_ALU_LSH_K; |
| 433 | break; |
Kris Katterjohn | 9369986 | 2006-01-04 13:58:36 -0800 | [diff] [blame] | 434 | case BPF_ALU|BPF_LSH|BPF_X: |
Hagen Paul Pfeifer | 01f2f3f | 2010-06-19 17:05:36 +0000 | [diff] [blame] | 435 | ftest->code = BPF_S_ALU_LSH_X; |
| 436 | break; |
Kris Katterjohn | 9369986 | 2006-01-04 13:58:36 -0800 | [diff] [blame] | 437 | case BPF_ALU|BPF_RSH|BPF_K: |
Hagen Paul Pfeifer | 01f2f3f | 2010-06-19 17:05:36 +0000 | [diff] [blame] | 438 | ftest->code = BPF_S_ALU_RSH_K; |
| 439 | break; |
Kris Katterjohn | 9369986 | 2006-01-04 13:58:36 -0800 | [diff] [blame] | 440 | case BPF_ALU|BPF_RSH|BPF_X: |
Hagen Paul Pfeifer | 01f2f3f | 2010-06-19 17:05:36 +0000 | [diff] [blame] | 441 | ftest->code = BPF_S_ALU_RSH_X; |
| 442 | break; |
Kris Katterjohn | 9369986 | 2006-01-04 13:58:36 -0800 | [diff] [blame] | 443 | case BPF_ALU|BPF_NEG: |
Hagen Paul Pfeifer | 01f2f3f | 2010-06-19 17:05:36 +0000 | [diff] [blame] | 444 | ftest->code = BPF_S_ALU_NEG; |
| 445 | break; |
Kris Katterjohn | 9369986 | 2006-01-04 13:58:36 -0800 | [diff] [blame] | 446 | case BPF_LD|BPF_W|BPF_ABS: |
Hagen Paul Pfeifer | 01f2f3f | 2010-06-19 17:05:36 +0000 | [diff] [blame] | 447 | ftest->code = BPF_S_LD_W_ABS; |
| 448 | break; |
Kris Katterjohn | 9369986 | 2006-01-04 13:58:36 -0800 | [diff] [blame] | 449 | case BPF_LD|BPF_H|BPF_ABS: |
Hagen Paul Pfeifer | 01f2f3f | 2010-06-19 17:05:36 +0000 | [diff] [blame] | 450 | ftest->code = BPF_S_LD_H_ABS; |
| 451 | break; |
Kris Katterjohn | 9369986 | 2006-01-04 13:58:36 -0800 | [diff] [blame] | 452 | case BPF_LD|BPF_B|BPF_ABS: |
Hagen Paul Pfeifer | 01f2f3f | 2010-06-19 17:05:36 +0000 | [diff] [blame] | 453 | ftest->code = BPF_S_LD_B_ABS; |
| 454 | break; |
Kris Katterjohn | 9369986 | 2006-01-04 13:58:36 -0800 | [diff] [blame] | 455 | case BPF_LD|BPF_W|BPF_LEN: |
Hagen Paul Pfeifer | 01f2f3f | 2010-06-19 17:05:36 +0000 | [diff] [blame] | 456 | ftest->code = BPF_S_LD_W_LEN; |
| 457 | break; |
Kris Katterjohn | 9369986 | 2006-01-04 13:58:36 -0800 | [diff] [blame] | 458 | case BPF_LD|BPF_W|BPF_IND: |
Hagen Paul Pfeifer | 01f2f3f | 2010-06-19 17:05:36 +0000 | [diff] [blame] | 459 | ftest->code = BPF_S_LD_W_IND; |
| 460 | break; |
Kris Katterjohn | 9369986 | 2006-01-04 13:58:36 -0800 | [diff] [blame] | 461 | case BPF_LD|BPF_H|BPF_IND: |
Hagen Paul Pfeifer | 01f2f3f | 2010-06-19 17:05:36 +0000 | [diff] [blame] | 462 | ftest->code = BPF_S_LD_H_IND; |
| 463 | break; |
Kris Katterjohn | 9369986 | 2006-01-04 13:58:36 -0800 | [diff] [blame] | 464 | case BPF_LD|BPF_B|BPF_IND: |
Hagen Paul Pfeifer | 01f2f3f | 2010-06-19 17:05:36 +0000 | [diff] [blame] | 465 | ftest->code = BPF_S_LD_B_IND; |
| 466 | break; |
Kris Katterjohn | 9369986 | 2006-01-04 13:58:36 -0800 | [diff] [blame] | 467 | case BPF_LD|BPF_IMM: |
Hagen Paul Pfeifer | 01f2f3f | 2010-06-19 17:05:36 +0000 | [diff] [blame] | 468 | ftest->code = BPF_S_LD_IMM; |
| 469 | break; |
Kris Katterjohn | 9369986 | 2006-01-04 13:58:36 -0800 | [diff] [blame] | 470 | case BPF_LDX|BPF_W|BPF_LEN: |
Hagen Paul Pfeifer | 01f2f3f | 2010-06-19 17:05:36 +0000 | [diff] [blame] | 471 | ftest->code = BPF_S_LDX_W_LEN; |
| 472 | break; |
Kris Katterjohn | 9369986 | 2006-01-04 13:58:36 -0800 | [diff] [blame] | 473 | case BPF_LDX|BPF_B|BPF_MSH: |
Hagen Paul Pfeifer | 01f2f3f | 2010-06-19 17:05:36 +0000 | [diff] [blame] | 474 | ftest->code = BPF_S_LDX_B_MSH; |
| 475 | break; |
Kris Katterjohn | 9369986 | 2006-01-04 13:58:36 -0800 | [diff] [blame] | 476 | case BPF_LDX|BPF_IMM: |
Hagen Paul Pfeifer | 01f2f3f | 2010-06-19 17:05:36 +0000 | [diff] [blame] | 477 | ftest->code = BPF_S_LDX_IMM; |
| 478 | break; |
Kris Katterjohn | 9369986 | 2006-01-04 13:58:36 -0800 | [diff] [blame] | 479 | case BPF_MISC|BPF_TAX: |
Hagen Paul Pfeifer | 01f2f3f | 2010-06-19 17:05:36 +0000 | [diff] [blame] | 480 | ftest->code = BPF_S_MISC_TAX; |
| 481 | break; |
Kris Katterjohn | 9369986 | 2006-01-04 13:58:36 -0800 | [diff] [blame] | 482 | case BPF_MISC|BPF_TXA: |
Hagen Paul Pfeifer | 01f2f3f | 2010-06-19 17:05:36 +0000 | [diff] [blame] | 483 | ftest->code = BPF_S_MISC_TXA; |
| 484 | break; |
Kris Katterjohn | 9369986 | 2006-01-04 13:58:36 -0800 | [diff] [blame] | 485 | case BPF_RET|BPF_K: |
Hagen Paul Pfeifer | 01f2f3f | 2010-06-19 17:05:36 +0000 | [diff] [blame] | 486 | ftest->code = BPF_S_RET_K; |
| 487 | break; |
Kris Katterjohn | 9369986 | 2006-01-04 13:58:36 -0800 | [diff] [blame] | 488 | case BPF_RET|BPF_A: |
Hagen Paul Pfeifer | 01f2f3f | 2010-06-19 17:05:36 +0000 | [diff] [blame] | 489 | ftest->code = BPF_S_RET_A; |
Kris Katterjohn | 9369986 | 2006-01-04 13:58:36 -0800 | [diff] [blame] | 490 | break; |
Kris Katterjohn | fb0d366 | 2005-11-20 13:41:34 -0800 | [diff] [blame] | 491 | |
Kris Katterjohn | 9369986 | 2006-01-04 13:58:36 -0800 | [diff] [blame] | 492 | /* Some instructions need special checks */ |
| 493 | |
Kris Katterjohn | 9369986 | 2006-01-04 13:58:36 -0800 | [diff] [blame] | 494 | /* check for division by zero */ |
Hagen Paul Pfeifer | 01f2f3f | 2010-06-19 17:05:36 +0000 | [diff] [blame] | 495 | case BPF_ALU|BPF_DIV|BPF_K: |
Kris Katterjohn | 9369986 | 2006-01-04 13:58:36 -0800 | [diff] [blame] | 496 | if (ftest->k == 0) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 497 | return -EINVAL; |
Hagen Paul Pfeifer | 01f2f3f | 2010-06-19 17:05:36 +0000 | [diff] [blame] | 498 | ftest->code = BPF_S_ALU_DIV_K; |
Kris Katterjohn | 9369986 | 2006-01-04 13:58:36 -0800 | [diff] [blame] | 499 | break; |
| 500 | |
Hagen Paul Pfeifer | 01f2f3f | 2010-06-19 17:05:36 +0000 | [diff] [blame] | 501 | /* check for invalid memory addresses */ |
Kris Katterjohn | 9369986 | 2006-01-04 13:58:36 -0800 | [diff] [blame] | 502 | case BPF_LD|BPF_MEM: |
Kris Katterjohn | 9369986 | 2006-01-04 13:58:36 -0800 | [diff] [blame] | 503 | if (ftest->k >= BPF_MEMWORDS) |
| 504 | return -EINVAL; |
Hagen Paul Pfeifer | 01f2f3f | 2010-06-19 17:05:36 +0000 | [diff] [blame] | 505 | ftest->code = BPF_S_LD_MEM; |
| 506 | break; |
| 507 | case BPF_LDX|BPF_MEM: |
| 508 | if (ftest->k >= BPF_MEMWORDS) |
| 509 | return -EINVAL; |
| 510 | ftest->code = BPF_S_LDX_MEM; |
| 511 | break; |
| 512 | case BPF_ST: |
| 513 | if (ftest->k >= BPF_MEMWORDS) |
| 514 | return -EINVAL; |
| 515 | ftest->code = BPF_S_ST; |
| 516 | break; |
| 517 | case BPF_STX: |
| 518 | if (ftest->k >= BPF_MEMWORDS) |
| 519 | return -EINVAL; |
| 520 | ftest->code = BPF_S_STX; |
Kris Katterjohn | 9369986 | 2006-01-04 13:58:36 -0800 | [diff] [blame] | 521 | break; |
| 522 | |
| 523 | case BPF_JMP|BPF_JA: |
| 524 | /* |
| 525 | * Note, the large ftest->k might cause loops. |
| 526 | * Compare this with conditional jumps below, |
| 527 | * where offsets are limited. --ANK (981016) |
| 528 | */ |
| 529 | if (ftest->k >= (unsigned)(flen-pc-1)) |
| 530 | return -EINVAL; |
Hagen Paul Pfeifer | 01f2f3f | 2010-06-19 17:05:36 +0000 | [diff] [blame] | 531 | ftest->code = BPF_S_JMP_JA; |
Kris Katterjohn | 9369986 | 2006-01-04 13:58:36 -0800 | [diff] [blame] | 532 | break; |
| 533 | |
| 534 | case BPF_JMP|BPF_JEQ|BPF_K: |
Hagen Paul Pfeifer | 01f2f3f | 2010-06-19 17:05:36 +0000 | [diff] [blame] | 535 | ftest->code = BPF_S_JMP_JEQ_K; |
| 536 | break; |
Kris Katterjohn | 9369986 | 2006-01-04 13:58:36 -0800 | [diff] [blame] | 537 | case BPF_JMP|BPF_JEQ|BPF_X: |
Hagen Paul Pfeifer | 01f2f3f | 2010-06-19 17:05:36 +0000 | [diff] [blame] | 538 | ftest->code = BPF_S_JMP_JEQ_X; |
| 539 | break; |
Kris Katterjohn | 9369986 | 2006-01-04 13:58:36 -0800 | [diff] [blame] | 540 | case BPF_JMP|BPF_JGE|BPF_K: |
Hagen Paul Pfeifer | 01f2f3f | 2010-06-19 17:05:36 +0000 | [diff] [blame] | 541 | ftest->code = BPF_S_JMP_JGE_K; |
| 542 | break; |
Kris Katterjohn | 9369986 | 2006-01-04 13:58:36 -0800 | [diff] [blame] | 543 | case BPF_JMP|BPF_JGE|BPF_X: |
Hagen Paul Pfeifer | 01f2f3f | 2010-06-19 17:05:36 +0000 | [diff] [blame] | 544 | ftest->code = BPF_S_JMP_JGE_X; |
| 545 | break; |
Kris Katterjohn | 9369986 | 2006-01-04 13:58:36 -0800 | [diff] [blame] | 546 | case BPF_JMP|BPF_JGT|BPF_K: |
Hagen Paul Pfeifer | 01f2f3f | 2010-06-19 17:05:36 +0000 | [diff] [blame] | 547 | ftest->code = BPF_S_JMP_JGT_K; |
| 548 | break; |
Kris Katterjohn | 9369986 | 2006-01-04 13:58:36 -0800 | [diff] [blame] | 549 | case BPF_JMP|BPF_JGT|BPF_X: |
Hagen Paul Pfeifer | 01f2f3f | 2010-06-19 17:05:36 +0000 | [diff] [blame] | 550 | ftest->code = BPF_S_JMP_JGT_X; |
| 551 | break; |
Kris Katterjohn | 9369986 | 2006-01-04 13:58:36 -0800 | [diff] [blame] | 552 | case BPF_JMP|BPF_JSET|BPF_K: |
Hagen Paul Pfeifer | 01f2f3f | 2010-06-19 17:05:36 +0000 | [diff] [blame] | 553 | ftest->code = BPF_S_JMP_JSET_K; |
| 554 | break; |
Kris Katterjohn | 9369986 | 2006-01-04 13:58:36 -0800 | [diff] [blame] | 555 | case BPF_JMP|BPF_JSET|BPF_X: |
Hagen Paul Pfeifer | 01f2f3f | 2010-06-19 17:05:36 +0000 | [diff] [blame] | 556 | ftest->code = BPF_S_JMP_JSET_X; |
Kris Katterjohn | 9369986 | 2006-01-04 13:58:36 -0800 | [diff] [blame] | 557 | break; |
| 558 | |
| 559 | default: |
| 560 | return -EINVAL; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 561 | } |
Hagen Paul Pfeifer | 01f2f3f | 2010-06-19 17:05:36 +0000 | [diff] [blame] | 562 | |
| 563 | /* for conditionals both must be safe */ |
| 564 | switch (ftest->code) { |
| 565 | case BPF_S_JMP_JEQ_K: |
| 566 | case BPF_S_JMP_JEQ_X: |
| 567 | case BPF_S_JMP_JGE_K: |
| 568 | case BPF_S_JMP_JGE_X: |
| 569 | case BPF_S_JMP_JGT_K: |
| 570 | case BPF_S_JMP_JGT_X: |
| 571 | case BPF_S_JMP_JSET_X: |
| 572 | case BPF_S_JMP_JSET_K: |
| 573 | if (pc + ftest->jt + 1 >= flen || |
| 574 | pc + ftest->jf + 1 >= flen) |
| 575 | return -EINVAL; |
| 576 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 577 | } |
| 578 | |
Hagen Paul Pfeifer | 01f2f3f | 2010-06-19 17:05:36 +0000 | [diff] [blame] | 579 | /* last instruction must be a RET code */ |
| 580 | switch (filter[flen - 1].code) { |
| 581 | case BPF_S_RET_K: |
| 582 | case BPF_S_RET_A: |
| 583 | return 0; |
| 584 | break; |
| 585 | default: |
| 586 | return -EINVAL; |
| 587 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 588 | } |
Stephen Hemminger | b715631 | 2008-04-10 01:33:47 -0700 | [diff] [blame] | 589 | EXPORT_SYMBOL(sk_chk_filter); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 590 | |
| 591 | /** |
Pavel Emelyanov | 47e958e | 2007-10-17 21:22:42 -0700 | [diff] [blame] | 592 | * sk_filter_rcu_release: Release a socket filter by rcu_head |
| 593 | * @rcu: rcu_head that contains the sk_filter to free |
| 594 | */ |
| 595 | static void sk_filter_rcu_release(struct rcu_head *rcu) |
| 596 | { |
| 597 | struct sk_filter *fp = container_of(rcu, struct sk_filter, rcu); |
| 598 | |
| 599 | sk_filter_release(fp); |
| 600 | } |
| 601 | |
| 602 | static void sk_filter_delayed_uncharge(struct sock *sk, struct sk_filter *fp) |
| 603 | { |
| 604 | unsigned int size = sk_filter_len(fp); |
| 605 | |
| 606 | atomic_sub(size, &sk->sk_omem_alloc); |
| 607 | call_rcu_bh(&fp->rcu, sk_filter_rcu_release); |
| 608 | } |
| 609 | |
| 610 | /** |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 611 | * sk_attach_filter - attach a socket filter |
| 612 | * @fprog: the filter program |
| 613 | * @sk: the socket to use |
| 614 | * |
| 615 | * Attach the user's filter code. We first run some sanity checks on |
| 616 | * it to make sure it does not explode on us later. If an error |
| 617 | * occurs or there is insufficient memory for the filter a negative |
| 618 | * errno code is returned. On success the return is zero. |
| 619 | */ |
| 620 | int sk_attach_filter(struct sock_fprog *fprog, struct sock *sk) |
| 621 | { |
Pavel Emelyanov | d3904b7 | 2007-10-17 21:22:17 -0700 | [diff] [blame] | 622 | struct sk_filter *fp, *old_fp; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 623 | unsigned int fsize = sizeof(struct sock_filter) * fprog->len; |
| 624 | int err; |
| 625 | |
| 626 | /* Make sure new filter is there and in the right amounts. */ |
Kris Katterjohn | e35bedf | 2006-01-17 02:25:52 -0800 | [diff] [blame] | 627 | if (fprog->filter == NULL) |
| 628 | return -EINVAL; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 629 | |
| 630 | fp = sock_kmalloc(sk, fsize+sizeof(*fp), GFP_KERNEL); |
| 631 | if (!fp) |
| 632 | return -ENOMEM; |
| 633 | if (copy_from_user(fp->insns, fprog->filter, fsize)) { |
YOSHIFUJI Hideaki | 4ec93ed | 2007-02-09 23:24:36 +0900 | [diff] [blame] | 634 | sock_kfree_s(sk, fp, fsize+sizeof(*fp)); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 635 | return -EFAULT; |
| 636 | } |
| 637 | |
| 638 | atomic_set(&fp->refcnt, 1); |
| 639 | fp->len = fprog->len; |
| 640 | |
| 641 | err = sk_chk_filter(fp->insns, fp->len); |
Pavel Emelyanov | d3904b7 | 2007-10-17 21:22:17 -0700 | [diff] [blame] | 642 | if (err) { |
| 643 | sk_filter_uncharge(sk, fp); |
| 644 | return err; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 645 | } |
| 646 | |
Eric Dumazet | f91ff5b | 2010-09-27 06:07:30 +0000 | [diff] [blame] | 647 | old_fp = rcu_dereference_protected(sk->sk_filter, |
| 648 | sock_owned_by_user(sk)); |
Pavel Emelyanov | d3904b7 | 2007-10-17 21:22:17 -0700 | [diff] [blame] | 649 | rcu_assign_pointer(sk->sk_filter, fp); |
Pavel Emelyanov | d3904b7 | 2007-10-17 21:22:17 -0700 | [diff] [blame] | 650 | |
Olof Johansson | 9b013e0 | 2007-10-18 21:48:39 -0700 | [diff] [blame] | 651 | if (old_fp) |
| 652 | sk_filter_delayed_uncharge(sk, old_fp); |
Pavel Emelyanov | d3904b7 | 2007-10-17 21:22:17 -0700 | [diff] [blame] | 653 | return 0; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 654 | } |
Michael S. Tsirkin | 5ff3f07 | 2010-02-14 01:01:00 +0000 | [diff] [blame] | 655 | EXPORT_SYMBOL_GPL(sk_attach_filter); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 656 | |
Pavel Emelyanov | 55b3332 | 2007-10-17 21:21:26 -0700 | [diff] [blame] | 657 | int sk_detach_filter(struct sock *sk) |
| 658 | { |
| 659 | int ret = -ENOENT; |
| 660 | struct sk_filter *filter; |
| 661 | |
Eric Dumazet | f91ff5b | 2010-09-27 06:07:30 +0000 | [diff] [blame] | 662 | filter = rcu_dereference_protected(sk->sk_filter, |
| 663 | sock_owned_by_user(sk)); |
Pavel Emelyanov | 55b3332 | 2007-10-17 21:21:26 -0700 | [diff] [blame] | 664 | if (filter) { |
| 665 | rcu_assign_pointer(sk->sk_filter, NULL); |
Pavel Emelyanov | 47e958e | 2007-10-17 21:22:42 -0700 | [diff] [blame] | 666 | sk_filter_delayed_uncharge(sk, filter); |
Pavel Emelyanov | 55b3332 | 2007-10-17 21:21:26 -0700 | [diff] [blame] | 667 | ret = 0; |
| 668 | } |
Pavel Emelyanov | 55b3332 | 2007-10-17 21:21:26 -0700 | [diff] [blame] | 669 | return ret; |
| 670 | } |
Michael S. Tsirkin | 5ff3f07 | 2010-02-14 01:01:00 +0000 | [diff] [blame] | 671 | EXPORT_SYMBOL_GPL(sk_detach_filter); |