Commit | Line | Data |
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1da177e4 LT |
1 | /* Kernel module to match AH parameters. */ |
2 | ||
3 | /* (C) 2001-2002 Andras Kis-Szabo <kisza@sch.bme.hu> | |
4 | * | |
5 | * This program is free software; you can redistribute it and/or modify | |
6 | * it under the terms of the GNU General Public License version 2 as | |
7 | * published by the Free Software Foundation. | |
8 | */ | |
9 | ||
10 | #include <linux/module.h> | |
11 | #include <linux/skbuff.h> | |
14c85021 | 12 | #include <linux/ip.h> |
1da177e4 LT |
13 | #include <linux/ipv6.h> |
14 | #include <linux/types.h> | |
15 | #include <net/checksum.h> | |
16 | #include <net/ipv6.h> | |
17 | ||
6709dbbb | 18 | #include <linux/netfilter/x_tables.h> |
1da177e4 LT |
19 | #include <linux/netfilter_ipv6/ip6_tables.h> |
20 | #include <linux/netfilter_ipv6/ip6t_ah.h> | |
21 | ||
22 | MODULE_LICENSE("GPL"); | |
2ae15b64 | 23 | MODULE_DESCRIPTION("Xtables: IPv6 IPsec-AH match"); |
1da177e4 LT |
24 | MODULE_AUTHOR("Andras Kis-Szabo <kisza@sch.bme.hu>"); |
25 | ||
1da177e4 | 26 | /* Returns 1 if the spi is matched by the range, 0 otherwise */ |
1d93a9cb JE |
27 | static inline bool |
28 | spi_match(u_int32_t min, u_int32_t max, u_int32_t spi, bool invert) | |
1da177e4 | 29 | { |
1d93a9cb | 30 | bool r; |
0d53778e PM |
31 | |
32 | pr_debug("ah spi_match:%c 0x%x <= 0x%x <= 0x%x", | |
33 | invert ? '!' : ' ', min, spi, max); | |
1da177e4 | 34 | r = (spi >= min && spi <= max) ^ invert; |
0d53778e | 35 | pr_debug(" result %s\n", r ? "PASS" : "FAILED"); |
1da177e4 LT |
36 | return r; |
37 | } | |
38 | ||
f7108a20 | 39 | static bool ah_mt6(const struct sk_buff *skb, const struct xt_match_param *par) |
1da177e4 | 40 | { |
a47362a2 JE |
41 | struct ip_auth_hdr _ah; |
42 | const struct ip_auth_hdr *ah; | |
f7108a20 | 43 | const struct ip6t_ah *ahinfo = par->matchinfo; |
1da177e4 LT |
44 | unsigned int ptr; |
45 | unsigned int hdrlen = 0; | |
6d381634 | 46 | int err; |
1da177e4 | 47 | |
6d381634 PM |
48 | err = ipv6_find_hdr(skb, &ptr, NEXTHDR_AUTH, NULL); |
49 | if (err < 0) { | |
50 | if (err != -ENOENT) | |
f7108a20 | 51 | *par->hotdrop = true; |
1d93a9cb | 52 | return false; |
6d381634 | 53 | } |
1da177e4 | 54 | |
e674d0f3 YK |
55 | ah = skb_header_pointer(skb, ptr, sizeof(_ah), &_ah); |
56 | if (ah == NULL) { | |
f7108a20 | 57 | *par->hotdrop = true; |
1d93a9cb | 58 | return false; |
1da177e4 LT |
59 | } |
60 | ||
e674d0f3 | 61 | hdrlen = (ah->hdrlen + 2) << 2; |
1da177e4 | 62 | |
0d53778e PM |
63 | pr_debug("IPv6 AH LEN %u %u ", hdrlen, ah->hdrlen); |
64 | pr_debug("RES %04X ", ah->reserved); | |
65 | pr_debug("SPI %u %08X\n", ntohl(ah->spi), ntohl(ah->spi)); | |
66 | ||
67 | pr_debug("IPv6 AH spi %02X ", | |
68 | spi_match(ahinfo->spis[0], ahinfo->spis[1], | |
69 | ntohl(ah->spi), | |
70 | !!(ahinfo->invflags & IP6T_AH_INV_SPI))); | |
71 | pr_debug("len %02X %04X %02X ", | |
72 | ahinfo->hdrlen, hdrlen, | |
73 | (!ahinfo->hdrlen || | |
74 | (ahinfo->hdrlen == hdrlen) ^ | |
75 | !!(ahinfo->invflags & IP6T_AH_INV_LEN))); | |
76 | pr_debug("res %02X %04X %02X\n", | |
77 | ahinfo->hdrres, ah->reserved, | |
78 | !(ahinfo->hdrres && ah->reserved)); | |
1da177e4 LT |
79 | |
80 | return (ah != NULL) | |
81 | && | |
7c4e36bc JE |
82 | spi_match(ahinfo->spis[0], ahinfo->spis[1], |
83 | ntohl(ah->spi), | |
84 | !!(ahinfo->invflags & IP6T_AH_INV_SPI)) | |
1da177e4 LT |
85 | && |
86 | (!ahinfo->hdrlen || | |
1ab1457c YH |
87 | (ahinfo->hdrlen == hdrlen) ^ |
88 | !!(ahinfo->invflags & IP6T_AH_INV_LEN)) | |
1da177e4 LT |
89 | && |
90 | !(ahinfo->hdrres && ah->reserved); | |
91 | } | |
92 | ||
9b4fce7a | 93 | static bool ah_mt6_check(const struct xt_mtchk_param *par) |
1da177e4 | 94 | { |
9b4fce7a | 95 | const struct ip6t_ah *ahinfo = par->matchinfo; |
1da177e4 | 96 | |
1da177e4 | 97 | if (ahinfo->invflags & ~IP6T_AH_INV_MASK) { |
0d53778e | 98 | pr_debug("ip6t_ah: unknown flags %X\n", ahinfo->invflags); |
ccb79bdc | 99 | return false; |
1da177e4 | 100 | } |
ccb79bdc | 101 | return true; |
1da177e4 LT |
102 | } |
103 | ||
d3c5ee6d | 104 | static struct xt_match ah_mt6_reg __read_mostly = { |
1da177e4 | 105 | .name = "ah", |
ee999d8b | 106 | .family = NFPROTO_IPV6, |
d3c5ee6d | 107 | .match = ah_mt6, |
7f939713 | 108 | .matchsize = sizeof(struct ip6t_ah), |
d3c5ee6d | 109 | .checkentry = ah_mt6_check, |
1da177e4 LT |
110 | .me = THIS_MODULE, |
111 | }; | |
112 | ||
d3c5ee6d | 113 | static int __init ah_mt6_init(void) |
1da177e4 | 114 | { |
d3c5ee6d | 115 | return xt_register_match(&ah_mt6_reg); |
1da177e4 LT |
116 | } |
117 | ||
d3c5ee6d | 118 | static void __exit ah_mt6_exit(void) |
1da177e4 | 119 | { |
d3c5ee6d | 120 | xt_unregister_match(&ah_mt6_reg); |
1da177e4 LT |
121 | } |
122 | ||
d3c5ee6d JE |
123 | module_init(ah_mt6_init); |
124 | module_exit(ah_mt6_exit); |