blob: 1ec49fe5845f1ec8f289f411d456a5765303e244 [file] [log] [blame]
Patrick McHardy96518512013-10-14 11:00:02 +02001/*
2 * Copyright (c) 2008 Patrick McHardy <kaber@trash.net>
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 *
8 * Development of this code funded by Astaro AG (http://www.astaro.com/)
9 */
10
11#include <linux/kernel.h>
12#include <linux/init.h>
13#include <linux/module.h>
14#include <linux/netlink.h>
15#include <linux/netfilter.h>
16#include <linux/netfilter/nf_tables.h>
17#include <net/netfilter/nf_tables.h>
Manuel Messner935b7f62017-02-07 03:14:53 +010018#include <net/tcp.h>
Patrick McHardy96518512013-10-14 11:00:02 +020019
20struct nft_exthdr {
21 u8 type;
22 u8 offset;
23 u8 len;
Manuel Messner935b7f62017-02-07 03:14:53 +010024 u8 op;
Patrick McHardy96518512013-10-14 11:00:02 +020025 enum nft_registers dreg:8;
Phil Sutterc078ca32017-01-17 22:51:26 +010026 u8 flags;
Patrick McHardy96518512013-10-14 11:00:02 +020027};
28
Manuel Messner935b7f62017-02-07 03:14:53 +010029static unsigned int optlen(const u8 *opt, unsigned int offset)
30{
31 /* Beware zero-length options: make finite progress */
32 if (opt[offset] <= TCPOPT_NOP || opt[offset + 1] == 0)
33 return 1;
34 else
35 return opt[offset + 1];
36}
37
38static void nft_exthdr_ipv6_eval(const struct nft_expr *expr,
39 struct nft_regs *regs,
40 const struct nft_pktinfo *pkt)
Patrick McHardy96518512013-10-14 11:00:02 +020041{
42 struct nft_exthdr *priv = nft_expr_priv(expr);
Patrick McHardy49499c32015-04-11 02:27:37 +010043 u32 *dest = &regs->data[priv->dreg];
Daniel Borkmann540436c2013-12-20 11:23:15 +010044 unsigned int offset = 0;
Patrick McHardy96518512013-10-14 11:00:02 +020045 int err;
46
47 err = ipv6_find_hdr(pkt->skb, &offset, priv->type, NULL, NULL);
Phil Sutterc078ca32017-01-17 22:51:26 +010048 if (priv->flags & NFT_EXTHDR_F_PRESENT) {
49 *dest = (err >= 0);
50 return;
51 } else if (err < 0) {
Patrick McHardy96518512013-10-14 11:00:02 +020052 goto err;
Phil Sutterc078ca32017-01-17 22:51:26 +010053 }
Patrick McHardy96518512013-10-14 11:00:02 +020054 offset += priv->offset;
55
Patrick McHardy49499c32015-04-11 02:27:37 +010056 dest[priv->len / NFT_REG32_SIZE] = 0;
Patrick McHardyfad136e2015-04-11 02:27:33 +010057 if (skb_copy_bits(pkt->skb, offset, dest, priv->len) < 0)
Patrick McHardy96518512013-10-14 11:00:02 +020058 goto err;
59 return;
60err:
Patrick McHardya55e22e2015-04-11 02:27:31 +010061 regs->verdict.code = NFT_BREAK;
Patrick McHardy96518512013-10-14 11:00:02 +020062}
63
Manuel Messner935b7f62017-02-07 03:14:53 +010064static void nft_exthdr_tcp_eval(const struct nft_expr *expr,
65 struct nft_regs *regs,
66 const struct nft_pktinfo *pkt)
67{
68 u8 buff[sizeof(struct tcphdr) + MAX_TCP_OPTION_SPACE];
69 struct nft_exthdr *priv = nft_expr_priv(expr);
70 unsigned int i, optl, tcphdr_len, offset;
71 u32 *dest = &regs->data[priv->dreg];
72 struct tcphdr *tcph;
73 u8 *opt;
74
75 if (!pkt->tprot_set || pkt->tprot != IPPROTO_TCP)
76 goto err;
77
78 tcph = skb_header_pointer(pkt->skb, pkt->xt.thoff, sizeof(*tcph), buff);
79 if (!tcph)
80 goto err;
81
82 tcphdr_len = __tcp_hdrlen(tcph);
83 if (tcphdr_len < sizeof(*tcph))
84 goto err;
85
86 tcph = skb_header_pointer(pkt->skb, pkt->xt.thoff, tcphdr_len, buff);
87 if (!tcph)
88 goto err;
89
90 opt = (u8 *)tcph;
91 for (i = sizeof(*tcph); i < tcphdr_len - 1; i += optl) {
92 optl = optlen(opt, i);
93
94 if (priv->type != opt[i])
95 continue;
96
97 if (i + optl > tcphdr_len || priv->len + priv->offset > optl)
98 goto err;
99
100 offset = i + priv->offset;
Phil Sutter3c1fece2017-02-20 17:52:27 +0100101 if (priv->flags & NFT_EXTHDR_F_PRESENT) {
102 *dest = 1;
103 } else {
104 dest[priv->len / NFT_REG32_SIZE] = 0;
105 memcpy(dest, opt + offset, priv->len);
106 }
Manuel Messner935b7f62017-02-07 03:14:53 +0100107
108 return;
109 }
110
111err:
Phil Sutter3c1fece2017-02-20 17:52:27 +0100112 if (priv->flags & NFT_EXTHDR_F_PRESENT)
113 *dest = 0;
114 else
115 regs->verdict.code = NFT_BREAK;
Manuel Messner935b7f62017-02-07 03:14:53 +0100116}
117
Patrick McHardy96518512013-10-14 11:00:02 +0200118static const struct nla_policy nft_exthdr_policy[NFTA_EXTHDR_MAX + 1] = {
119 [NFTA_EXTHDR_DREG] = { .type = NLA_U32 },
120 [NFTA_EXTHDR_TYPE] = { .type = NLA_U8 },
121 [NFTA_EXTHDR_OFFSET] = { .type = NLA_U32 },
122 [NFTA_EXTHDR_LEN] = { .type = NLA_U32 },
Phil Sutterc078ca32017-01-17 22:51:26 +0100123 [NFTA_EXTHDR_FLAGS] = { .type = NLA_U32 },
Patrick McHardy96518512013-10-14 11:00:02 +0200124};
125
126static int nft_exthdr_init(const struct nft_ctx *ctx,
127 const struct nft_expr *expr,
128 const struct nlattr * const tb[])
129{
130 struct nft_exthdr *priv = nft_expr_priv(expr);
Manuel Messner935b7f62017-02-07 03:14:53 +0100131 u32 offset, len, flags = 0, op = NFT_EXTHDR_OP_IPV6;
Dan Carpenter21a9e0f2016-10-12 09:09:12 +0300132 int err;
Patrick McHardy96518512013-10-14 11:00:02 +0200133
Manuel Messner935b7f62017-02-07 03:14:53 +0100134 if (!tb[NFTA_EXTHDR_DREG] ||
135 !tb[NFTA_EXTHDR_TYPE] ||
136 !tb[NFTA_EXTHDR_OFFSET] ||
137 !tb[NFTA_EXTHDR_LEN])
Patrick McHardy96518512013-10-14 11:00:02 +0200138 return -EINVAL;
139
Laura Garcia Liebana36b701f2016-09-14 15:00:02 +0200140 err = nft_parse_u32_check(tb[NFTA_EXTHDR_OFFSET], U8_MAX, &offset);
141 if (err < 0)
142 return err;
Laura Garcia Liebana4da449a2016-08-09 20:46:16 +0200143
Laura Garcia Liebana36b701f2016-09-14 15:00:02 +0200144 err = nft_parse_u32_check(tb[NFTA_EXTHDR_LEN], U8_MAX, &len);
145 if (err < 0)
146 return err;
Laura Garcia Liebana4da449a2016-08-09 20:46:16 +0200147
Phil Sutterc078ca32017-01-17 22:51:26 +0100148 if (tb[NFTA_EXTHDR_FLAGS]) {
149 err = nft_parse_u32_check(tb[NFTA_EXTHDR_FLAGS], U8_MAX, &flags);
150 if (err < 0)
151 return err;
152
153 if (flags & ~NFT_EXTHDR_F_PRESENT)
154 return -EINVAL;
155 }
156
Manuel Messner935b7f62017-02-07 03:14:53 +0100157 if (tb[NFTA_EXTHDR_OP]) {
158 err = nft_parse_u32_check(tb[NFTA_EXTHDR_OP], U8_MAX, &op);
159 if (err < 0)
160 return err;
161 }
162
Patrick McHardy96518512013-10-14 11:00:02 +0200163 priv->type = nla_get_u8(tb[NFTA_EXTHDR_TYPE]);
Laura Garcia Liebana4da449a2016-08-09 20:46:16 +0200164 priv->offset = offset;
165 priv->len = len;
Patrick McHardyb1c96ed2015-04-11 02:27:36 +0100166 priv->dreg = nft_parse_register(tb[NFTA_EXTHDR_DREG]);
Phil Sutterc078ca32017-01-17 22:51:26 +0100167 priv->flags = flags;
Manuel Messner935b7f62017-02-07 03:14:53 +0100168 priv->op = op;
Patrick McHardy96518512013-10-14 11:00:02 +0200169
Patrick McHardy1ec10212015-04-11 02:27:27 +0100170 return nft_validate_register_store(ctx, priv->dreg, NULL,
171 NFT_DATA_VALUE, priv->len);
Patrick McHardy96518512013-10-14 11:00:02 +0200172}
173
174static int nft_exthdr_dump(struct sk_buff *skb, const struct nft_expr *expr)
175{
176 const struct nft_exthdr *priv = nft_expr_priv(expr);
177
Patrick McHardyb1c96ed2015-04-11 02:27:36 +0100178 if (nft_dump_register(skb, NFTA_EXTHDR_DREG, priv->dreg))
Patrick McHardy96518512013-10-14 11:00:02 +0200179 goto nla_put_failure;
180 if (nla_put_u8(skb, NFTA_EXTHDR_TYPE, priv->type))
181 goto nla_put_failure;
182 if (nla_put_be32(skb, NFTA_EXTHDR_OFFSET, htonl(priv->offset)))
183 goto nla_put_failure;
184 if (nla_put_be32(skb, NFTA_EXTHDR_LEN, htonl(priv->len)))
185 goto nla_put_failure;
Phil Sutterc078ca32017-01-17 22:51:26 +0100186 if (nla_put_be32(skb, NFTA_EXTHDR_FLAGS, htonl(priv->flags)))
187 goto nla_put_failure;
Manuel Messner935b7f62017-02-07 03:14:53 +0100188 if (nla_put_be32(skb, NFTA_EXTHDR_OP, htonl(priv->op)))
189 goto nla_put_failure;
Patrick McHardy96518512013-10-14 11:00:02 +0200190 return 0;
191
192nla_put_failure:
193 return -1;
194}
195
Patrick McHardyef1f7df2013-10-10 11:41:20 +0200196static struct nft_expr_type nft_exthdr_type;
Manuel Messner935b7f62017-02-07 03:14:53 +0100197static const struct nft_expr_ops nft_exthdr_ipv6_ops = {
Patrick McHardyef1f7df2013-10-10 11:41:20 +0200198 .type = &nft_exthdr_type,
Patrick McHardy96518512013-10-14 11:00:02 +0200199 .size = NFT_EXPR_SIZE(sizeof(struct nft_exthdr)),
Manuel Messner935b7f62017-02-07 03:14:53 +0100200 .eval = nft_exthdr_ipv6_eval,
Patrick McHardy96518512013-10-14 11:00:02 +0200201 .init = nft_exthdr_init,
202 .dump = nft_exthdr_dump,
Patrick McHardyef1f7df2013-10-10 11:41:20 +0200203};
204
Manuel Messner935b7f62017-02-07 03:14:53 +0100205static const struct nft_expr_ops nft_exthdr_tcp_ops = {
206 .type = &nft_exthdr_type,
207 .size = NFT_EXPR_SIZE(sizeof(struct nft_exthdr)),
208 .eval = nft_exthdr_tcp_eval,
209 .init = nft_exthdr_init,
210 .dump = nft_exthdr_dump,
211};
212
213static const struct nft_expr_ops *
214nft_exthdr_select_ops(const struct nft_ctx *ctx,
215 const struct nlattr * const tb[])
216{
217 u32 op;
218
219 if (!tb[NFTA_EXTHDR_OP])
220 return &nft_exthdr_ipv6_ops;
221
222 op = ntohl(nla_get_u32(tb[NFTA_EXTHDR_OP]));
223 switch (op) {
224 case NFT_EXTHDR_OP_TCPOPT:
225 return &nft_exthdr_tcp_ops;
226 case NFT_EXTHDR_OP_IPV6:
227 return &nft_exthdr_ipv6_ops;
228 }
229
230 return ERR_PTR(-EOPNOTSUPP);
231}
232
Patrick McHardyef1f7df2013-10-10 11:41:20 +0200233static struct nft_expr_type nft_exthdr_type __read_mostly = {
234 .name = "exthdr",
Arushi Singhald4ef3832017-04-02 14:52:12 +0530235 .select_ops = nft_exthdr_select_ops,
Patrick McHardy96518512013-10-14 11:00:02 +0200236 .policy = nft_exthdr_policy,
237 .maxattr = NFTA_EXTHDR_MAX,
Patrick McHardyef1f7df2013-10-10 11:41:20 +0200238 .owner = THIS_MODULE,
Patrick McHardy96518512013-10-14 11:00:02 +0200239};
240
241static int __init nft_exthdr_module_init(void)
242{
Patrick McHardyef1f7df2013-10-10 11:41:20 +0200243 return nft_register_expr(&nft_exthdr_type);
Patrick McHardy96518512013-10-14 11:00:02 +0200244}
245
246static void __exit nft_exthdr_module_exit(void)
247{
Patrick McHardyef1f7df2013-10-10 11:41:20 +0200248 nft_unregister_expr(&nft_exthdr_type);
Patrick McHardy96518512013-10-14 11:00:02 +0200249}
250
251module_init(nft_exthdr_module_init);
252module_exit(nft_exthdr_module_exit);
253
254MODULE_LICENSE("GPL");
255MODULE_AUTHOR("Patrick McHardy <kaber@trash.net>");
256MODULE_ALIAS_NFT_EXPR("exthdr");