Commit | Line | Data |
---|---|---|
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"); | |
23 | MODULE_DESCRIPTION("IPv6 AH match"); | |
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 | ||
1d93a9cb | 39 | static bool |
1da177e4 LT |
40 | match(const struct sk_buff *skb, |
41 | const struct net_device *in, | |
42 | const struct net_device *out, | |
c4986734 | 43 | const struct xt_match *match, |
1da177e4 LT |
44 | const void *matchinfo, |
45 | int offset, | |
46 | unsigned int protoff, | |
cff533ac | 47 | bool *hotdrop) |
1da177e4 | 48 | { |
a47362a2 JE |
49 | struct ip_auth_hdr _ah; |
50 | const struct ip_auth_hdr *ah; | |
1da177e4 | 51 | const struct ip6t_ah *ahinfo = matchinfo; |
1da177e4 LT |
52 | unsigned int ptr; |
53 | unsigned int hdrlen = 0; | |
6d381634 | 54 | int err; |
1da177e4 | 55 | |
6d381634 PM |
56 | err = ipv6_find_hdr(skb, &ptr, NEXTHDR_AUTH, NULL); |
57 | if (err < 0) { | |
58 | if (err != -ENOENT) | |
cff533ac | 59 | *hotdrop = true; |
1d93a9cb | 60 | return false; |
6d381634 | 61 | } |
1da177e4 | 62 | |
e674d0f3 YK |
63 | ah = skb_header_pointer(skb, ptr, sizeof(_ah), &_ah); |
64 | if (ah == NULL) { | |
cff533ac | 65 | *hotdrop = true; |
1d93a9cb | 66 | return false; |
1da177e4 LT |
67 | } |
68 | ||
e674d0f3 | 69 | hdrlen = (ah->hdrlen + 2) << 2; |
1da177e4 | 70 | |
0d53778e PM |
71 | pr_debug("IPv6 AH LEN %u %u ", hdrlen, ah->hdrlen); |
72 | pr_debug("RES %04X ", ah->reserved); | |
73 | pr_debug("SPI %u %08X\n", ntohl(ah->spi), ntohl(ah->spi)); | |
74 | ||
75 | pr_debug("IPv6 AH spi %02X ", | |
76 | spi_match(ahinfo->spis[0], ahinfo->spis[1], | |
77 | ntohl(ah->spi), | |
78 | !!(ahinfo->invflags & IP6T_AH_INV_SPI))); | |
79 | pr_debug("len %02X %04X %02X ", | |
80 | ahinfo->hdrlen, hdrlen, | |
81 | (!ahinfo->hdrlen || | |
82 | (ahinfo->hdrlen == hdrlen) ^ | |
83 | !!(ahinfo->invflags & IP6T_AH_INV_LEN))); | |
84 | pr_debug("res %02X %04X %02X\n", | |
85 | ahinfo->hdrres, ah->reserved, | |
86 | !(ahinfo->hdrres && ah->reserved)); | |
1da177e4 LT |
87 | |
88 | return (ah != NULL) | |
89 | && | |
7c4e36bc JE |
90 | spi_match(ahinfo->spis[0], ahinfo->spis[1], |
91 | ntohl(ah->spi), | |
92 | !!(ahinfo->invflags & IP6T_AH_INV_SPI)) | |
1da177e4 LT |
93 | && |
94 | (!ahinfo->hdrlen || | |
1ab1457c YH |
95 | (ahinfo->hdrlen == hdrlen) ^ |
96 | !!(ahinfo->invflags & IP6T_AH_INV_LEN)) | |
1da177e4 LT |
97 | && |
98 | !(ahinfo->hdrres && ah->reserved); | |
99 | } | |
100 | ||
101 | /* Called when user tries to insert an entry of this type. */ | |
ccb79bdc | 102 | static bool |
1da177e4 | 103 | checkentry(const char *tablename, |
1ab1457c | 104 | const void *entry, |
c4986734 | 105 | const struct xt_match *match, |
1ab1457c YH |
106 | void *matchinfo, |
107 | unsigned int hook_mask) | |
1da177e4 LT |
108 | { |
109 | const struct ip6t_ah *ahinfo = matchinfo; | |
110 | ||
1da177e4 | 111 | if (ahinfo->invflags & ~IP6T_AH_INV_MASK) { |
0d53778e | 112 | pr_debug("ip6t_ah: unknown flags %X\n", ahinfo->invflags); |
ccb79bdc | 113 | return false; |
1da177e4 | 114 | } |
ccb79bdc | 115 | return true; |
1da177e4 LT |
116 | } |
117 | ||
9f15c530 | 118 | static struct xt_match ah_match __read_mostly = { |
1da177e4 | 119 | .name = "ah", |
6709dbbb | 120 | .family = AF_INET6, |
7f939713 PM |
121 | .match = match, |
122 | .matchsize = sizeof(struct ip6t_ah), | |
123 | .checkentry = checkentry, | |
1da177e4 LT |
124 | .me = THIS_MODULE, |
125 | }; | |
126 | ||
65b4b4e8 | 127 | static int __init ip6t_ah_init(void) |
1da177e4 | 128 | { |
6709dbbb | 129 | return xt_register_match(&ah_match); |
1da177e4 LT |
130 | } |
131 | ||
65b4b4e8 | 132 | static void __exit ip6t_ah_fini(void) |
1da177e4 | 133 | { |
6709dbbb | 134 | xt_unregister_match(&ah_match); |
1da177e4 LT |
135 | } |
136 | ||
65b4b4e8 AM |
137 | module_init(ip6t_ah_init); |
138 | module_exit(ip6t_ah_fini); |