Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1 | /* Kernel module to match AH parameters. */ |
| 2 | /* (C) 1999-2000 Yon Uriarte <yon@astaro.de> |
| 3 | * |
| 4 | * This program is free software; you can redistribute it and/or modify |
| 5 | * it under the terms of the GNU General Public License version 2 as |
| 6 | * published by the Free Software Foundation. |
| 7 | */ |
Jan Engelhardt | be91fd5 | 2010-03-18 02:22:32 +0100 | [diff] [blame] | 8 | #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt |
Jan Engelhardt | 6709dbb | 2007-02-07 15:11:19 -0800 | [diff] [blame] | 9 | #include <linux/in.h> |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 10 | #include <linux/module.h> |
| 11 | #include <linux/skbuff.h> |
| 12 | #include <linux/ip.h> |
| 13 | |
| 14 | #include <linux/netfilter_ipv4/ipt_ah.h> |
Jan Engelhardt | 6709dbb | 2007-02-07 15:11:19 -0800 | [diff] [blame] | 15 | #include <linux/netfilter/x_tables.h> |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 16 | |
| 17 | MODULE_LICENSE("GPL"); |
| 18 | MODULE_AUTHOR("Yon Uriarte <yon@astaro.de>"); |
Jan Engelhardt | 2ae15b6 | 2008-01-14 23:42:28 -0800 | [diff] [blame] | 19 | MODULE_DESCRIPTION("Xtables: IPv4 IPsec-AH SPI match"); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 20 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 21 | /* Returns 1 if the spi is matched by the range, 0 otherwise */ |
Jan Engelhardt | 1d93a9c | 2007-07-07 22:15:35 -0700 | [diff] [blame] | 22 | static inline bool |
| 23 | spi_match(u_int32_t min, u_int32_t max, u_int32_t spi, bool invert) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 24 | { |
Jan Engelhardt | 1d93a9c | 2007-07-07 22:15:35 -0700 | [diff] [blame] | 25 | bool r; |
Jan Engelhardt | be91fd5 | 2010-03-18 02:22:32 +0100 | [diff] [blame] | 26 | pr_debug("spi_match:%c 0x%x <= 0x%x <= 0x%x\n", |
| 27 | invert ? '!' : ' ', min, spi, max); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 28 | r=(spi >= min && spi <= max) ^ invert; |
Jan Engelhardt | be91fd5 | 2010-03-18 02:22:32 +0100 | [diff] [blame] | 29 | pr_debug(" result %s\n", r ? "PASS" : "FAILED"); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 30 | return r; |
| 31 | } |
| 32 | |
Jan Engelhardt | 62fc805 | 2009-07-07 20:42:08 +0200 | [diff] [blame] | 33 | static bool ah_mt(const struct sk_buff *skb, struct xt_action_param *par) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 34 | { |
Jan Engelhardt | a47362a | 2007-07-07 22:16:55 -0700 | [diff] [blame] | 35 | struct ip_auth_hdr _ahdr; |
| 36 | const struct ip_auth_hdr *ah; |
Jan Engelhardt | f7108a2 | 2008-10-08 11:35:18 +0200 | [diff] [blame] | 37 | const struct ipt_ah *ahinfo = par->matchinfo; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 38 | |
| 39 | /* Must not be a fragment. */ |
Jan Engelhardt | f7108a2 | 2008-10-08 11:35:18 +0200 | [diff] [blame] | 40 | if (par->fragoff != 0) |
Jan Engelhardt | 1d93a9c | 2007-07-07 22:15:35 -0700 | [diff] [blame] | 41 | return false; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 42 | |
Jan Engelhardt | f7108a2 | 2008-10-08 11:35:18 +0200 | [diff] [blame] | 43 | ah = skb_header_pointer(skb, par->thoff, sizeof(_ahdr), &_ahdr); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 44 | if (ah == NULL) { |
| 45 | /* We've been asked to examine this packet, and we |
| 46 | * can't. Hence, no choice but to drop. |
| 47 | */ |
Jan Engelhardt | be91fd5 | 2010-03-18 02:22:32 +0100 | [diff] [blame] | 48 | pr_debug("Dropping evil AH tinygram.\n"); |
Jan Engelhardt | b4ba261 | 2009-07-07 20:54:30 +0200 | [diff] [blame] | 49 | par->hotdrop = true; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 50 | return 0; |
| 51 | } |
| 52 | |
| 53 | return spi_match(ahinfo->spis[0], ahinfo->spis[1], |
| 54 | ntohl(ah->spi), |
| 55 | !!(ahinfo->invflags & IPT_AH_INV_SPI)); |
| 56 | } |
| 57 | |
Jan Engelhardt | b0f3845 | 2010-03-19 17:16:42 +0100 | [diff] [blame] | 58 | static int ah_mt_check(const struct xt_mtchk_param *par) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 59 | { |
Jan Engelhardt | 9b4fce7 | 2008-10-08 11:35:18 +0200 | [diff] [blame] | 60 | const struct ipt_ah *ahinfo = par->matchinfo; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 61 | |
Patrick McHardy | 1d5cd90 | 2006-03-20 18:01:14 -0800 | [diff] [blame] | 62 | /* Must specify no unknown invflags */ |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 63 | if (ahinfo->invflags & ~IPT_AH_INV_MASK) { |
Jan Engelhardt | be91fd5 | 2010-03-18 02:22:32 +0100 | [diff] [blame] | 64 | pr_debug("unknown flags %X\n", ahinfo->invflags); |
Jan Engelhardt | bd414ee | 2010-03-23 16:35:56 +0100 | [diff] [blame] | 65 | return -EINVAL; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 66 | } |
Jan Engelhardt | bd414ee | 2010-03-23 16:35:56 +0100 | [diff] [blame] | 67 | return 0; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 68 | } |
| 69 | |
Jan Engelhardt | d3c5ee6 | 2007-12-04 23:24:03 -0800 | [diff] [blame] | 70 | static struct xt_match ah_mt_reg __read_mostly = { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 71 | .name = "ah", |
Jan Engelhardt | ee999d8 | 2008-10-08 11:35:01 +0200 | [diff] [blame] | 72 | .family = NFPROTO_IPV4, |
Jan Engelhardt | d3c5ee6 | 2007-12-04 23:24:03 -0800 | [diff] [blame] | 73 | .match = ah_mt, |
Patrick McHardy | 1d5cd90 | 2006-03-20 18:01:14 -0800 | [diff] [blame] | 74 | .matchsize = sizeof(struct ipt_ah), |
| 75 | .proto = IPPROTO_AH, |
Jan Engelhardt | d3c5ee6 | 2007-12-04 23:24:03 -0800 | [diff] [blame] | 76 | .checkentry = ah_mt_check, |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 77 | .me = THIS_MODULE, |
| 78 | }; |
| 79 | |
Jan Engelhardt | d3c5ee6 | 2007-12-04 23:24:03 -0800 | [diff] [blame] | 80 | static int __init ah_mt_init(void) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 81 | { |
Jan Engelhardt | d3c5ee6 | 2007-12-04 23:24:03 -0800 | [diff] [blame] | 82 | return xt_register_match(&ah_mt_reg); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 83 | } |
| 84 | |
Jan Engelhardt | d3c5ee6 | 2007-12-04 23:24:03 -0800 | [diff] [blame] | 85 | static void __exit ah_mt_exit(void) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 86 | { |
Jan Engelhardt | d3c5ee6 | 2007-12-04 23:24:03 -0800 | [diff] [blame] | 87 | xt_unregister_match(&ah_mt_reg); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 88 | } |
| 89 | |
Jan Engelhardt | d3c5ee6 | 2007-12-04 23:24:03 -0800 | [diff] [blame] | 90 | module_init(ah_mt_init); |
| 91 | module_exit(ah_mt_exit); |