Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1 | /* Kernel module to match FRAG 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 | */ |
Jan Engelhardt | ff67e4e | 2010-03-19 21:08:16 +0100 | [diff] [blame] | 9 | #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt |
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/ipv6.h> |
| 13 | #include <linux/types.h> |
| 14 | #include <net/checksum.h> |
| 15 | #include <net/ipv6.h> |
| 16 | |
Jan Engelhardt | 6709dbb | 2007-02-07 15:11:19 -0800 | [diff] [blame] | 17 | #include <linux/netfilter/x_tables.h> |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 18 | #include <linux/netfilter_ipv6/ip6_tables.h> |
| 19 | #include <linux/netfilter_ipv6/ip6t_frag.h> |
| 20 | |
| 21 | MODULE_LICENSE("GPL"); |
Jan Engelhardt | 2ae15b6 | 2008-01-14 23:42:28 -0800 | [diff] [blame] | 22 | MODULE_DESCRIPTION("Xtables: IPv6 fragment match"); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 23 | MODULE_AUTHOR("Andras Kis-Szabo <kisza@sch.bme.hu>"); |
| 24 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 25 | /* Returns 1 if the id is matched by the range, 0 otherwise */ |
Jan Engelhardt | 1d93a9c | 2007-07-07 22:15:35 -0700 | [diff] [blame] | 26 | static inline bool |
| 27 | id_match(u_int32_t min, u_int32_t max, u_int32_t id, bool invert) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 28 | { |
Jan Engelhardt | 1d93a9c | 2007-07-07 22:15:35 -0700 | [diff] [blame] | 29 | bool r; |
Jan Engelhardt | ff67e4e | 2010-03-19 21:08:16 +0100 | [diff] [blame] | 30 | pr_debug("id_match:%c 0x%x <= 0x%x <= 0x%x\n", invert ? '!' : ' ', |
Patrick McHardy | 0d53778 | 2007-07-07 22:39:38 -0700 | [diff] [blame] | 31 | min, id, max); |
Yasuyuki Kozakai | f0daaa6 | 2006-01-17 02:39:39 -0800 | [diff] [blame] | 32 | r = (id >= min && id <= max) ^ invert; |
Patrick McHardy | 0d53778 | 2007-07-07 22:39:38 -0700 | [diff] [blame] | 33 | pr_debug(" result %s\n", r ? "PASS" : "FAILED"); |
Yasuyuki Kozakai | f0daaa6 | 2006-01-17 02:39:39 -0800 | [diff] [blame] | 34 | return r; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 35 | } |
| 36 | |
Jan Engelhardt | 1d93a9c | 2007-07-07 22:15:35 -0700 | [diff] [blame] | 37 | static bool |
Jan Engelhardt | 62fc805 | 2009-07-07 20:42:08 +0200 | [diff] [blame] | 38 | frag_mt6(const struct sk_buff *skb, struct xt_action_param *par) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 39 | { |
Jan Engelhardt | a47362a | 2007-07-07 22:16:55 -0700 | [diff] [blame] | 40 | struct frag_hdr _frag; |
| 41 | const struct frag_hdr *fh; |
Jan Engelhardt | f7108a2 | 2008-10-08 11:35:18 +0200 | [diff] [blame] | 42 | const struct ip6t_frag *fraginfo = par->matchinfo; |
Hans Schillstrom | 84018f5 | 2012-04-23 03:35:26 +0000 | [diff] [blame] | 43 | unsigned int ptr = 0; |
Patrick McHardy | 6d38163 | 2006-10-24 16:15:10 -0700 | [diff] [blame] | 44 | int err; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 45 | |
Hans Schillstrom | 84018f5 | 2012-04-23 03:35:26 +0000 | [diff] [blame] | 46 | err = ipv6_find_hdr(skb, &ptr, NEXTHDR_FRAGMENT, NULL, NULL); |
Patrick McHardy | 6d38163 | 2006-10-24 16:15:10 -0700 | [diff] [blame] | 47 | if (err < 0) { |
| 48 | if (err != -ENOENT) |
Jan Engelhardt | b4ba261 | 2009-07-07 20:54:30 +0200 | [diff] [blame] | 49 | par->hotdrop = true; |
Jan Engelhardt | 1d93a9c | 2007-07-07 22:15:35 -0700 | [diff] [blame] | 50 | return false; |
Patrick McHardy | 6d38163 | 2006-10-24 16:15:10 -0700 | [diff] [blame] | 51 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 52 | |
Yasuyuki Kozakai | e674d0f | 2005-09-19 15:34:40 -0700 | [diff] [blame] | 53 | fh = skb_header_pointer(skb, ptr, sizeof(_frag), &_frag); |
Yasuyuki Kozakai | f0daaa6 | 2006-01-17 02:39:39 -0800 | [diff] [blame] | 54 | if (fh == NULL) { |
Jan Engelhardt | b4ba261 | 2009-07-07 20:54:30 +0200 | [diff] [blame] | 55 | par->hotdrop = true; |
Jan Engelhardt | 1d93a9c | 2007-07-07 22:15:35 -0700 | [diff] [blame] | 56 | return false; |
Yasuyuki Kozakai | e674d0f | 2005-09-19 15:34:40 -0700 | [diff] [blame] | 57 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 58 | |
Patrick McHardy | 0d53778 | 2007-07-07 22:39:38 -0700 | [diff] [blame] | 59 | pr_debug("INFO %04X ", fh->frag_off); |
| 60 | pr_debug("OFFSET %04X ", ntohs(fh->frag_off) & ~0x7); |
| 61 | pr_debug("RES %02X %04X", fh->reserved, ntohs(fh->frag_off) & 0x6); |
| 62 | pr_debug("MF %04X ", fh->frag_off & htons(IP6_MF)); |
| 63 | pr_debug("ID %u %08X\n", ntohl(fh->identification), |
| 64 | ntohl(fh->identification)); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 65 | |
Patrick McHardy | 0d53778 | 2007-07-07 22:39:38 -0700 | [diff] [blame] | 66 | pr_debug("IPv6 FRAG id %02X ", |
| 67 | id_match(fraginfo->ids[0], fraginfo->ids[1], |
| 68 | ntohl(fh->identification), |
| 69 | !!(fraginfo->invflags & IP6T_FRAG_INV_IDS))); |
| 70 | pr_debug("res %02X %02X%04X %02X ", |
| 71 | fraginfo->flags & IP6T_FRAG_RES, fh->reserved, |
| 72 | ntohs(fh->frag_off) & 0x6, |
Joe Perches | 3666ed1 | 2009-11-23 23:17:06 +0100 | [diff] [blame] | 73 | !((fraginfo->flags & IP6T_FRAG_RES) && |
| 74 | (fh->reserved || (ntohs(fh->frag_off) & 0x06)))); |
Patrick McHardy | 0d53778 | 2007-07-07 22:39:38 -0700 | [diff] [blame] | 75 | pr_debug("first %02X %02X %02X ", |
| 76 | fraginfo->flags & IP6T_FRAG_FST, |
| 77 | ntohs(fh->frag_off) & ~0x7, |
Joe Perches | 3666ed1 | 2009-11-23 23:17:06 +0100 | [diff] [blame] | 78 | !((fraginfo->flags & IP6T_FRAG_FST) && |
| 79 | (ntohs(fh->frag_off) & ~0x7))); |
Patrick McHardy | 0d53778 | 2007-07-07 22:39:38 -0700 | [diff] [blame] | 80 | pr_debug("mf %02X %02X %02X ", |
| 81 | fraginfo->flags & IP6T_FRAG_MF, |
| 82 | ntohs(fh->frag_off) & IP6_MF, |
Joe Perches | 3666ed1 | 2009-11-23 23:17:06 +0100 | [diff] [blame] | 83 | !((fraginfo->flags & IP6T_FRAG_MF) && |
| 84 | !((ntohs(fh->frag_off) & IP6_MF)))); |
Patrick McHardy | 0d53778 | 2007-07-07 22:39:38 -0700 | [diff] [blame] | 85 | pr_debug("last %02X %02X %02X\n", |
| 86 | fraginfo->flags & IP6T_FRAG_NMF, |
| 87 | ntohs(fh->frag_off) & IP6_MF, |
Joe Perches | 3666ed1 | 2009-11-23 23:17:06 +0100 | [diff] [blame] | 88 | !((fraginfo->flags & IP6T_FRAG_NMF) && |
| 89 | (ntohs(fh->frag_off) & IP6_MF))); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 90 | |
Joe Perches | 3666ed1 | 2009-11-23 23:17:06 +0100 | [diff] [blame] | 91 | return (fh != NULL) && |
| 92 | id_match(fraginfo->ids[0], fraginfo->ids[1], |
| 93 | ntohl(fh->identification), |
| 94 | !!(fraginfo->invflags & IP6T_FRAG_INV_IDS)) && |
| 95 | !((fraginfo->flags & IP6T_FRAG_RES) && |
| 96 | (fh->reserved || (ntohs(fh->frag_off) & 0x6))) && |
| 97 | !((fraginfo->flags & IP6T_FRAG_FST) && |
| 98 | (ntohs(fh->frag_off) & ~0x7)) && |
| 99 | !((fraginfo->flags & IP6T_FRAG_MF) && |
| 100 | !(ntohs(fh->frag_off) & IP6_MF)) && |
| 101 | !((fraginfo->flags & IP6T_FRAG_NMF) && |
| 102 | (ntohs(fh->frag_off) & IP6_MF)); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 103 | } |
| 104 | |
Jan Engelhardt | b0f3845 | 2010-03-19 17:16:42 +0100 | [diff] [blame] | 105 | static int frag_mt6_check(const struct xt_mtchk_param *par) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 106 | { |
Jan Engelhardt | 9b4fce7 | 2008-10-08 11:35:18 +0200 | [diff] [blame] | 107 | const struct ip6t_frag *fraginfo = par->matchinfo; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 108 | |
Yasuyuki Kozakai | f0daaa6 | 2006-01-17 02:39:39 -0800 | [diff] [blame] | 109 | if (fraginfo->invflags & ~IP6T_FRAG_INV_MASK) { |
Jan Engelhardt | ff67e4e | 2010-03-19 21:08:16 +0100 | [diff] [blame] | 110 | pr_debug("unknown flags %X\n", fraginfo->invflags); |
Jan Engelhardt | bd414ee | 2010-03-23 16:35:56 +0100 | [diff] [blame] | 111 | return -EINVAL; |
Yasuyuki Kozakai | f0daaa6 | 2006-01-17 02:39:39 -0800 | [diff] [blame] | 112 | } |
Jan Engelhardt | bd414ee | 2010-03-23 16:35:56 +0100 | [diff] [blame] | 113 | return 0; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 114 | } |
| 115 | |
Jan Engelhardt | d3c5ee6 | 2007-12-04 23:24:03 -0800 | [diff] [blame] | 116 | static struct xt_match frag_mt6_reg __read_mostly = { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 117 | .name = "frag", |
Jan Engelhardt | ee999d8 | 2008-10-08 11:35:01 +0200 | [diff] [blame] | 118 | .family = NFPROTO_IPV6, |
Jan Engelhardt | d3c5ee6 | 2007-12-04 23:24:03 -0800 | [diff] [blame] | 119 | .match = frag_mt6, |
Patrick McHardy | 7f93971 | 2006-03-20 18:01:43 -0800 | [diff] [blame] | 120 | .matchsize = sizeof(struct ip6t_frag), |
Jan Engelhardt | d3c5ee6 | 2007-12-04 23:24:03 -0800 | [diff] [blame] | 121 | .checkentry = frag_mt6_check, |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 122 | .me = THIS_MODULE, |
| 123 | }; |
| 124 | |
Jan Engelhardt | d3c5ee6 | 2007-12-04 23:24:03 -0800 | [diff] [blame] | 125 | static int __init frag_mt6_init(void) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 126 | { |
Jan Engelhardt | d3c5ee6 | 2007-12-04 23:24:03 -0800 | [diff] [blame] | 127 | return xt_register_match(&frag_mt6_reg); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 128 | } |
| 129 | |
Jan Engelhardt | d3c5ee6 | 2007-12-04 23:24:03 -0800 | [diff] [blame] | 130 | static void __exit frag_mt6_exit(void) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 131 | { |
Jan Engelhardt | d3c5ee6 | 2007-12-04 23:24:03 -0800 | [diff] [blame] | 132 | xt_unregister_match(&frag_mt6_reg); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 133 | } |
| 134 | |
Jan Engelhardt | d3c5ee6 | 2007-12-04 23:24:03 -0800 | [diff] [blame] | 135 | module_init(frag_mt6_init); |
| 136 | module_exit(frag_mt6_exit); |