Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1 | #include <linux/module.h> |
| 2 | #include <linux/skbuff.h> |
| 3 | #include <net/ip.h> |
Harald Welte | 2e4e6a1 | 2006-01-12 13:30:04 -0800 | [diff] [blame] | 4 | #include <net/ipv6.h> |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 5 | #include <linux/sctp.h> |
| 6 | |
Harald Welte | 2e4e6a1 | 2006-01-12 13:30:04 -0800 | [diff] [blame] | 7 | #include <linux/netfilter/x_tables.h> |
| 8 | #include <linux/netfilter/xt_sctp.h> |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 9 | #include <linux/netfilter_ipv4/ip_tables.h> |
Harald Welte | 2e4e6a1 | 2006-01-12 13:30:04 -0800 | [diff] [blame] | 10 | #include <linux/netfilter_ipv6/ip6_tables.h> |
| 11 | |
| 12 | MODULE_LICENSE("GPL"); |
| 13 | MODULE_AUTHOR("Kiran Kumar Immidi"); |
| 14 | MODULE_DESCRIPTION("Match for SCTP protocol packets"); |
| 15 | MODULE_ALIAS("ipt_sctp"); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 16 | |
| 17 | #ifdef DEBUG_SCTP |
| 18 | #define duprintf(format, args...) printk(format , ## args) |
| 19 | #else |
| 20 | #define duprintf(format, args...) |
| 21 | #endif |
| 22 | |
| 23 | #define SCCHECK(cond, option, flag, invflag) (!((flag) & (option)) \ |
| 24 | || (!!((invflag) & (option)) ^ (cond))) |
| 25 | |
Jan Engelhardt | 1d93a9c | 2007-07-07 22:15:35 -0700 | [diff] [blame] | 26 | static bool |
Harald Welte | 2e4e6a1 | 2006-01-12 13:30:04 -0800 | [diff] [blame] | 27 | match_flags(const struct xt_sctp_flag_info *flag_info, |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 28 | const int flag_count, |
| 29 | u_int8_t chunktype, |
| 30 | u_int8_t chunkflags) |
| 31 | { |
| 32 | int i; |
| 33 | |
Jan Engelhardt | 7c4e36b | 2007-07-07 22:19:08 -0700 | [diff] [blame] | 34 | for (i = 0; i < flag_count; i++) |
| 35 | if (flag_info[i].chunktype == chunktype) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 36 | return (chunkflags & flag_info[i].flag_mask) == flag_info[i].flag; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 37 | |
Jan Engelhardt | 1d93a9c | 2007-07-07 22:15:35 -0700 | [diff] [blame] | 38 | return true; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 39 | } |
| 40 | |
Jan Engelhardt | 1d93a9c | 2007-07-07 22:15:35 -0700 | [diff] [blame] | 41 | static inline bool |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 42 | match_packet(const struct sk_buff *skb, |
Harald Welte | 2e4e6a1 | 2006-01-12 13:30:04 -0800 | [diff] [blame] | 43 | unsigned int offset, |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 44 | const u_int32_t *chunkmap, |
| 45 | int chunk_match_type, |
Harald Welte | 2e4e6a1 | 2006-01-12 13:30:04 -0800 | [diff] [blame] | 46 | const struct xt_sctp_flag_info *flag_info, |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 47 | const int flag_count, |
Jan Engelhardt | cff533a | 2007-07-07 22:15:12 -0700 | [diff] [blame] | 48 | bool *hotdrop) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 49 | { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 50 | u_int32_t chunkmapcopy[256 / sizeof (u_int32_t)]; |
| 51 | sctp_chunkhdr_t _sch, *sch; |
| 52 | |
| 53 | #ifdef DEBUG_SCTP |
| 54 | int i = 0; |
| 55 | #endif |
| 56 | |
Jan Engelhardt | 7c4e36b | 2007-07-07 22:19:08 -0700 | [diff] [blame] | 57 | if (chunk_match_type == SCTP_CHUNK_MATCH_ALL) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 58 | SCTP_CHUNKMAP_COPY(chunkmapcopy, chunkmap); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 59 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 60 | do { |
| 61 | sch = skb_header_pointer(skb, offset, sizeof(_sch), &_sch); |
Patrick McHardy | d3dcd4e | 2006-06-19 23:39:45 -0700 | [diff] [blame] | 62 | if (sch == NULL || sch->length == 0) { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 63 | duprintf("Dropping invalid SCTP packet.\n"); |
Jan Engelhardt | cff533a | 2007-07-07 22:15:12 -0700 | [diff] [blame] | 64 | *hotdrop = true; |
Jan Engelhardt | 1d93a9c | 2007-07-07 22:15:35 -0700 | [diff] [blame] | 65 | return false; |
YOSHIFUJI Hideaki | 601e68e | 2007-02-12 11:15:49 -0800 | [diff] [blame] | 66 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 67 | |
YOSHIFUJI Hideaki | 601e68e | 2007-02-12 11:15:49 -0800 | [diff] [blame] | 68 | duprintf("Chunk num: %d\toffset: %d\ttype: %d\tlength: %d\tflags: %x\n", |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 69 | ++i, offset, sch->type, htons(sch->length), sch->flags); |
| 70 | |
Al Viro | 962c837 | 2006-11-20 17:26:08 -0800 | [diff] [blame] | 71 | offset += (ntohs(sch->length) + 3) & ~3; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 72 | |
| 73 | duprintf("skb->len: %d\toffset: %d\n", skb->len, offset); |
| 74 | |
| 75 | if (SCTP_CHUNKMAP_IS_SET(chunkmap, sch->type)) { |
| 76 | switch (chunk_match_type) { |
| 77 | case SCTP_CHUNK_MATCH_ANY: |
YOSHIFUJI Hideaki | 601e68e | 2007-02-12 11:15:49 -0800 | [diff] [blame] | 78 | if (match_flags(flag_info, flag_count, |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 79 | sch->type, sch->flags)) { |
Jan Engelhardt | 1d93a9c | 2007-07-07 22:15:35 -0700 | [diff] [blame] | 80 | return true; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 81 | } |
| 82 | break; |
| 83 | |
| 84 | case SCTP_CHUNK_MATCH_ALL: |
YOSHIFUJI Hideaki | 601e68e | 2007-02-12 11:15:49 -0800 | [diff] [blame] | 85 | if (match_flags(flag_info, flag_count, |
Jan Engelhardt | 7c4e36b | 2007-07-07 22:19:08 -0700 | [diff] [blame] | 86 | sch->type, sch->flags)) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 87 | SCTP_CHUNKMAP_CLEAR(chunkmapcopy, sch->type); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 88 | break; |
| 89 | |
| 90 | case SCTP_CHUNK_MATCH_ONLY: |
YOSHIFUJI Hideaki | 601e68e | 2007-02-12 11:15:49 -0800 | [diff] [blame] | 91 | if (!match_flags(flag_info, flag_count, |
Jan Engelhardt | 7c4e36b | 2007-07-07 22:19:08 -0700 | [diff] [blame] | 92 | sch->type, sch->flags)) |
Jan Engelhardt | 1d93a9c | 2007-07-07 22:15:35 -0700 | [diff] [blame] | 93 | return false; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 94 | break; |
| 95 | } |
| 96 | } else { |
| 97 | switch (chunk_match_type) { |
| 98 | case SCTP_CHUNK_MATCH_ONLY: |
Jan Engelhardt | 1d93a9c | 2007-07-07 22:15:35 -0700 | [diff] [blame] | 99 | return false; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 100 | } |
| 101 | } |
| 102 | } while (offset < skb->len); |
| 103 | |
| 104 | switch (chunk_match_type) { |
| 105 | case SCTP_CHUNK_MATCH_ALL: |
| 106 | return SCTP_CHUNKMAP_IS_CLEAR(chunkmap); |
| 107 | case SCTP_CHUNK_MATCH_ANY: |
Jan Engelhardt | 1d93a9c | 2007-07-07 22:15:35 -0700 | [diff] [blame] | 108 | return false; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 109 | case SCTP_CHUNK_MATCH_ONLY: |
Jan Engelhardt | 1d93a9c | 2007-07-07 22:15:35 -0700 | [diff] [blame] | 110 | return true; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 111 | } |
| 112 | |
| 113 | /* This will never be reached, but required to stop compiler whine */ |
Jan Engelhardt | 1d93a9c | 2007-07-07 22:15:35 -0700 | [diff] [blame] | 114 | return false; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 115 | } |
| 116 | |
Jan Engelhardt | 1d93a9c | 2007-07-07 22:15:35 -0700 | [diff] [blame] | 117 | static bool |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 118 | match(const struct sk_buff *skb, |
| 119 | const struct net_device *in, |
| 120 | const struct net_device *out, |
Patrick McHardy | c498673 | 2006-03-20 18:02:56 -0800 | [diff] [blame] | 121 | const struct xt_match *match, |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 122 | const void *matchinfo, |
| 123 | int offset, |
Harald Welte | 2e4e6a1 | 2006-01-12 13:30:04 -0800 | [diff] [blame] | 124 | unsigned int protoff, |
Jan Engelhardt | cff533a | 2007-07-07 22:15:12 -0700 | [diff] [blame] | 125 | bool *hotdrop) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 126 | { |
Patrick McHardy | 3e72b2f | 2006-05-29 18:19:19 -0700 | [diff] [blame] | 127 | const struct xt_sctp_info *info = matchinfo; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 128 | sctp_sctphdr_t _sh, *sh; |
| 129 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 130 | if (offset) { |
| 131 | duprintf("Dropping non-first fragment.. FIXME\n"); |
Jan Engelhardt | 1d93a9c | 2007-07-07 22:15:35 -0700 | [diff] [blame] | 132 | return false; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 133 | } |
YOSHIFUJI Hideaki | 601e68e | 2007-02-12 11:15:49 -0800 | [diff] [blame] | 134 | |
Harald Welte | 2e4e6a1 | 2006-01-12 13:30:04 -0800 | [diff] [blame] | 135 | sh = skb_header_pointer(skb, protoff, sizeof(_sh), &_sh); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 136 | if (sh == NULL) { |
| 137 | duprintf("Dropping evil TCP offset=0 tinygram.\n"); |
Jan Engelhardt | cff533a | 2007-07-07 22:15:12 -0700 | [diff] [blame] | 138 | *hotdrop = true; |
Jan Engelhardt | 1d93a9c | 2007-07-07 22:15:35 -0700 | [diff] [blame] | 139 | return false; |
YOSHIFUJI Hideaki | 601e68e | 2007-02-12 11:15:49 -0800 | [diff] [blame] | 140 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 141 | duprintf("spt: %d\tdpt: %d\n", ntohs(sh->source), ntohs(sh->dest)); |
| 142 | |
Jan Engelhardt | 7c4e36b | 2007-07-07 22:19:08 -0700 | [diff] [blame] | 143 | return SCCHECK(ntohs(sh->source) >= info->spts[0] |
| 144 | && ntohs(sh->source) <= info->spts[1], |
YOSHIFUJI Hideaki | 601e68e | 2007-02-12 11:15:49 -0800 | [diff] [blame] | 145 | XT_SCTP_SRC_PORTS, info->flags, info->invflags) |
Jan Engelhardt | 7c4e36b | 2007-07-07 22:19:08 -0700 | [diff] [blame] | 146 | && SCCHECK(ntohs(sh->dest) >= info->dpts[0] |
| 147 | && ntohs(sh->dest) <= info->dpts[1], |
Harald Welte | 2e4e6a1 | 2006-01-12 13:30:04 -0800 | [diff] [blame] | 148 | XT_SCTP_DEST_PORTS, info->flags, info->invflags) |
Jorge Matias | 1c7e477 | 2006-06-27 03:01:25 -0700 | [diff] [blame] | 149 | && SCCHECK(match_packet(skb, protoff + sizeof (sctp_sctphdr_t), |
Harald Welte | 2e4e6a1 | 2006-01-12 13:30:04 -0800 | [diff] [blame] | 150 | info->chunkmap, info->chunk_match_type, |
YOSHIFUJI Hideaki | 601e68e | 2007-02-12 11:15:49 -0800 | [diff] [blame] | 151 | info->flag_info, info->flag_count, |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 152 | hotdrop), |
Harald Welte | 2e4e6a1 | 2006-01-12 13:30:04 -0800 | [diff] [blame] | 153 | XT_SCTP_CHUNK_TYPES, info->flags, info->invflags); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 154 | } |
| 155 | |
Jan Engelhardt | ccb79bd | 2007-07-07 22:16:00 -0700 | [diff] [blame] | 156 | static bool |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 157 | checkentry(const char *tablename, |
Harald Welte | 2e4e6a1 | 2006-01-12 13:30:04 -0800 | [diff] [blame] | 158 | const void *inf, |
Patrick McHardy | c498673 | 2006-03-20 18:02:56 -0800 | [diff] [blame] | 159 | const struct xt_match *match, |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 160 | void *matchinfo, |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 161 | unsigned int hook_mask) |
| 162 | { |
Patrick McHardy | 5d04bff | 2006-03-20 18:01:58 -0800 | [diff] [blame] | 163 | const struct xt_sctp_info *info = matchinfo; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 164 | |
Patrick McHardy | 5d04bff | 2006-03-20 18:01:58 -0800 | [diff] [blame] | 165 | return !(info->flags & ~XT_SCTP_VALID_FLAGS) |
Harald Welte | 2e4e6a1 | 2006-01-12 13:30:04 -0800 | [diff] [blame] | 166 | && !(info->invflags & ~XT_SCTP_VALID_FLAGS) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 167 | && !(info->invflags & ~info->flags) |
YOSHIFUJI Hideaki | 601e68e | 2007-02-12 11:15:49 -0800 | [diff] [blame] | 168 | && ((!(info->flags & XT_SCTP_CHUNK_TYPES)) || |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 169 | (info->chunk_match_type & |
YOSHIFUJI Hideaki | 601e68e | 2007-02-12 11:15:49 -0800 | [diff] [blame] | 170 | (SCTP_CHUNK_MATCH_ALL |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 171 | | SCTP_CHUNK_MATCH_ANY |
| 172 | | SCTP_CHUNK_MATCH_ONLY))); |
| 173 | } |
| 174 | |
Patrick McHardy | 9f15c53 | 2007-07-07 22:22:02 -0700 | [diff] [blame^] | 175 | static struct xt_match xt_sctp_match[] __read_mostly = { |
Patrick McHardy | 4470bbc | 2006-08-22 00:34:04 -0700 | [diff] [blame] | 176 | { |
| 177 | .name = "sctp", |
| 178 | .family = AF_INET, |
| 179 | .checkentry = checkentry, |
| 180 | .match = match, |
| 181 | .matchsize = sizeof(struct xt_sctp_info), |
| 182 | .proto = IPPROTO_SCTP, |
| 183 | .me = THIS_MODULE |
| 184 | }, |
| 185 | { |
| 186 | .name = "sctp", |
| 187 | .family = AF_INET6, |
| 188 | .checkentry = checkentry, |
| 189 | .match = match, |
| 190 | .matchsize = sizeof(struct xt_sctp_info), |
| 191 | .proto = IPPROTO_SCTP, |
| 192 | .me = THIS_MODULE |
| 193 | }, |
Patrick McHardy | 5d04bff | 2006-03-20 18:01:58 -0800 | [diff] [blame] | 194 | }; |
Harald Welte | 2e4e6a1 | 2006-01-12 13:30:04 -0800 | [diff] [blame] | 195 | |
Andrew Morton | 65b4b4e | 2006-03-28 16:37:06 -0800 | [diff] [blame] | 196 | static int __init xt_sctp_init(void) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 197 | { |
Patrick McHardy | 4470bbc | 2006-08-22 00:34:04 -0700 | [diff] [blame] | 198 | return xt_register_matches(xt_sctp_match, ARRAY_SIZE(xt_sctp_match)); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 199 | } |
| 200 | |
Andrew Morton | 65b4b4e | 2006-03-28 16:37:06 -0800 | [diff] [blame] | 201 | static void __exit xt_sctp_fini(void) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 202 | { |
Patrick McHardy | 4470bbc | 2006-08-22 00:34:04 -0700 | [diff] [blame] | 203 | xt_unregister_matches(xt_sctp_match, ARRAY_SIZE(xt_sctp_match)); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 204 | } |
| 205 | |
Andrew Morton | 65b4b4e | 2006-03-28 16:37:06 -0800 | [diff] [blame] | 206 | module_init(xt_sctp_init); |
| 207 | module_exit(xt_sctp_fini); |