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Commit | Line | Data |
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96518518 | 1 | /* |
ef1f7df9 | 2 | * Copyright (c) 2008-2009 Patrick McHardy <kaber@trash.net> |
18140969 | 3 | * Copyright (c) 2016 Pablo Neira Ayuso <pablo@netfilter.org> |
96518518 PM |
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 | * Development of this code funded by Astaro AG (http://www.astaro.com/) | |
10 | */ | |
11 | ||
12 | #include <linux/kernel.h> | |
8cfd23e6 | 13 | #include <linux/if_vlan.h> |
96518518 PM |
14 | #include <linux/init.h> |
15 | #include <linux/module.h> | |
16 | #include <linux/netlink.h> | |
17 | #include <linux/netfilter.h> | |
18 | #include <linux/netfilter/nf_tables.h> | |
19 | #include <net/netfilter/nf_tables_core.h> | |
20 | #include <net/netfilter/nf_tables.h> | |
18140969 PNA |
21 | /* For layer 4 checksum field offset. */ |
22 | #include <linux/tcp.h> | |
23 | #include <linux/udp.h> | |
24 | #include <linux/icmpv6.h> | |
96518518 | 25 | |
8cfd23e6 FW |
26 | /* add vlan header into the user buffer for if tag was removed by offloads */ |
27 | static bool | |
28 | nft_payload_copy_vlan(u32 *d, const struct sk_buff *skb, u8 offset, u8 len) | |
29 | { | |
30 | int mac_off = skb_mac_header(skb) - skb->data; | |
31 | u8 vlan_len, *vlanh, *dst_u8 = (u8 *) d; | |
32 | struct vlan_ethhdr veth; | |
33 | ||
34 | vlanh = (u8 *) &veth; | |
35 | if (offset < ETH_HLEN) { | |
36 | u8 ethlen = min_t(u8, len, ETH_HLEN - offset); | |
37 | ||
38 | if (skb_copy_bits(skb, mac_off, &veth, ETH_HLEN)) | |
39 | return false; | |
40 | ||
41 | veth.h_vlan_proto = skb->vlan_proto; | |
42 | ||
43 | memcpy(dst_u8, vlanh + offset, ethlen); | |
44 | ||
45 | len -= ethlen; | |
46 | if (len == 0) | |
47 | return true; | |
48 | ||
49 | dst_u8 += ethlen; | |
50 | offset = ETH_HLEN; | |
51 | } else if (offset >= VLAN_ETH_HLEN) { | |
52 | offset -= VLAN_HLEN; | |
53 | goto skip; | |
54 | } | |
55 | ||
56 | veth.h_vlan_TCI = htons(skb_vlan_tag_get(skb)); | |
57 | veth.h_vlan_encapsulated_proto = skb->protocol; | |
58 | ||
59 | vlanh += offset; | |
60 | ||
61 | vlan_len = min_t(u8, len, VLAN_ETH_HLEN - offset); | |
62 | memcpy(dst_u8, vlanh, vlan_len); | |
63 | ||
64 | len -= vlan_len; | |
65 | if (!len) | |
66 | return true; | |
67 | ||
68 | dst_u8 += vlan_len; | |
69 | skip: | |
70 | return skb_copy_bits(skb, offset + mac_off, dst_u8, len) == 0; | |
71 | } | |
72 | ||
96518518 | 73 | static void nft_payload_eval(const struct nft_expr *expr, |
a55e22e9 | 74 | struct nft_regs *regs, |
96518518 PM |
75 | const struct nft_pktinfo *pkt) |
76 | { | |
77 | const struct nft_payload *priv = nft_expr_priv(expr); | |
78 | const struct sk_buff *skb = pkt->skb; | |
49499c3e | 79 | u32 *dest = ®s->data[priv->dreg]; |
96518518 PM |
80 | int offset; |
81 | ||
8cfd23e6 | 82 | dest[priv->len / NFT_REG32_SIZE] = 0; |
96518518 PM |
83 | switch (priv->base) { |
84 | case NFT_PAYLOAD_LL_HEADER: | |
85 | if (!skb_mac_header_was_set(skb)) | |
86 | goto err; | |
8cfd23e6 FW |
87 | |
88 | if (skb_vlan_tag_present(skb)) { | |
89 | if (!nft_payload_copy_vlan(dest, skb, | |
90 | priv->offset, priv->len)) | |
91 | goto err; | |
92 | return; | |
93 | } | |
96518518 PM |
94 | offset = skb_mac_header(skb) - skb->data; |
95 | break; | |
96 | case NFT_PAYLOAD_NETWORK_HEADER: | |
97 | offset = skb_network_offset(skb); | |
98 | break; | |
99 | case NFT_PAYLOAD_TRANSPORT_HEADER: | |
a20877b5 LZ |
100 | if (!pkt->tprot_set) |
101 | goto err; | |
c54032e0 | 102 | offset = pkt->xt.thoff; |
96518518 PM |
103 | break; |
104 | default: | |
105 | BUG(); | |
106 | } | |
107 | offset += priv->offset; | |
108 | ||
fad136ea | 109 | if (skb_copy_bits(skb, offset, dest, priv->len) < 0) |
96518518 PM |
110 | goto err; |
111 | return; | |
112 | err: | |
a55e22e9 | 113 | regs->verdict.code = NFT_BREAK; |
96518518 PM |
114 | } |
115 | ||
116 | static const struct nla_policy nft_payload_policy[NFTA_PAYLOAD_MAX + 1] = { | |
7ec3f7b4 PM |
117 | [NFTA_PAYLOAD_SREG] = { .type = NLA_U32 }, |
118 | [NFTA_PAYLOAD_DREG] = { .type = NLA_U32 }, | |
119 | [NFTA_PAYLOAD_BASE] = { .type = NLA_U32 }, | |
120 | [NFTA_PAYLOAD_OFFSET] = { .type = NLA_U32 }, | |
121 | [NFTA_PAYLOAD_LEN] = { .type = NLA_U32 }, | |
122 | [NFTA_PAYLOAD_CSUM_TYPE] = { .type = NLA_U32 }, | |
123 | [NFTA_PAYLOAD_CSUM_OFFSET] = { .type = NLA_U32 }, | |
96518518 PM |
124 | }; |
125 | ||
126 | static int nft_payload_init(const struct nft_ctx *ctx, | |
127 | const struct nft_expr *expr, | |
128 | const struct nlattr * const tb[]) | |
129 | { | |
130 | struct nft_payload *priv = nft_expr_priv(expr); | |
96518518 | 131 | |
c29b72e0 | 132 | priv->base = ntohl(nla_get_be32(tb[NFTA_PAYLOAD_BASE])); |
96518518 PM |
133 | priv->offset = ntohl(nla_get_be32(tb[NFTA_PAYLOAD_OFFSET])); |
134 | priv->len = ntohl(nla_get_be32(tb[NFTA_PAYLOAD_LEN])); | |
b1c96ed3 | 135 | priv->dreg = nft_parse_register(tb[NFTA_PAYLOAD_DREG]); |
96518518 | 136 | |
1ec10212 PM |
137 | return nft_validate_register_store(ctx, priv->dreg, NULL, |
138 | NFT_DATA_VALUE, priv->len); | |
96518518 PM |
139 | } |
140 | ||
141 | static int nft_payload_dump(struct sk_buff *skb, const struct nft_expr *expr) | |
142 | { | |
143 | const struct nft_payload *priv = nft_expr_priv(expr); | |
144 | ||
b1c96ed3 | 145 | if (nft_dump_register(skb, NFTA_PAYLOAD_DREG, priv->dreg) || |
96518518 PM |
146 | nla_put_be32(skb, NFTA_PAYLOAD_BASE, htonl(priv->base)) || |
147 | nla_put_be32(skb, NFTA_PAYLOAD_OFFSET, htonl(priv->offset)) || | |
148 | nla_put_be32(skb, NFTA_PAYLOAD_LEN, htonl(priv->len))) | |
149 | goto nla_put_failure; | |
150 | return 0; | |
151 | ||
152 | nla_put_failure: | |
153 | return -1; | |
154 | } | |
155 | ||
ef1f7df9 PM |
156 | static const struct nft_expr_ops nft_payload_ops = { |
157 | .type = &nft_payload_type, | |
96518518 | 158 | .size = NFT_EXPR_SIZE(sizeof(struct nft_payload)), |
96518518 PM |
159 | .eval = nft_payload_eval, |
160 | .init = nft_payload_init, | |
161 | .dump = nft_payload_dump, | |
ef1f7df9 PM |
162 | }; |
163 | ||
c29b72e0 PM |
164 | const struct nft_expr_ops nft_payload_fast_ops = { |
165 | .type = &nft_payload_type, | |
166 | .size = NFT_EXPR_SIZE(sizeof(struct nft_payload)), | |
167 | .eval = nft_payload_eval, | |
168 | .init = nft_payload_init, | |
169 | .dump = nft_payload_dump, | |
170 | }; | |
171 | ||
18140969 PNA |
172 | static inline void nft_csum_replace(__sum16 *sum, __wsum fsum, __wsum tsum) |
173 | { | |
174 | *sum = csum_fold(csum_add(csum_sub(~csum_unfold(*sum), fsum), tsum)); | |
175 | if (*sum == 0) | |
176 | *sum = CSUM_MANGLED_0; | |
177 | } | |
178 | ||
179 | static bool nft_payload_udp_checksum(struct sk_buff *skb, unsigned int thoff) | |
180 | { | |
181 | struct udphdr *uh, _uh; | |
182 | ||
183 | uh = skb_header_pointer(skb, thoff, sizeof(_uh), &_uh); | |
184 | if (!uh) | |
185 | return false; | |
186 | ||
187 | return uh->check; | |
188 | } | |
189 | ||
190 | static int nft_payload_l4csum_offset(const struct nft_pktinfo *pkt, | |
191 | struct sk_buff *skb, | |
192 | unsigned int *l4csum_offset) | |
193 | { | |
194 | switch (pkt->tprot) { | |
195 | case IPPROTO_TCP: | |
196 | *l4csum_offset = offsetof(struct tcphdr, check); | |
197 | break; | |
198 | case IPPROTO_UDP: | |
199 | if (!nft_payload_udp_checksum(skb, pkt->xt.thoff)) | |
200 | return -1; | |
201 | /* Fall through. */ | |
202 | case IPPROTO_UDPLITE: | |
203 | *l4csum_offset = offsetof(struct udphdr, check); | |
204 | break; | |
205 | case IPPROTO_ICMPV6: | |
206 | *l4csum_offset = offsetof(struct icmp6hdr, icmp6_cksum); | |
207 | break; | |
208 | default: | |
209 | return -1; | |
210 | } | |
211 | ||
212 | *l4csum_offset += pkt->xt.thoff; | |
213 | return 0; | |
214 | } | |
215 | ||
216 | static int nft_payload_l4csum_update(const struct nft_pktinfo *pkt, | |
217 | struct sk_buff *skb, | |
218 | __wsum fsum, __wsum tsum) | |
219 | { | |
220 | int l4csum_offset; | |
221 | __sum16 sum; | |
222 | ||
223 | /* If we cannot determine layer 4 checksum offset or this packet doesn't | |
224 | * require layer 4 checksum recalculation, skip this packet. | |
225 | */ | |
226 | if (nft_payload_l4csum_offset(pkt, skb, &l4csum_offset) < 0) | |
227 | return 0; | |
228 | ||
229 | if (skb_copy_bits(skb, l4csum_offset, &sum, sizeof(sum)) < 0) | |
230 | return -1; | |
231 | ||
232 | /* Checksum mangling for an arbitrary amount of bytes, based on | |
233 | * inet_proto_csum_replace*() functions. | |
234 | */ | |
235 | if (skb->ip_summed != CHECKSUM_PARTIAL) { | |
236 | nft_csum_replace(&sum, fsum, tsum); | |
237 | if (skb->ip_summed == CHECKSUM_COMPLETE) { | |
238 | skb->csum = ~csum_add(csum_sub(~(skb->csum), fsum), | |
239 | tsum); | |
240 | } | |
241 | } else { | |
242 | sum = ~csum_fold(csum_add(csum_sub(csum_unfold(sum), fsum), | |
243 | tsum)); | |
244 | } | |
245 | ||
246 | if (!skb_make_writable(skb, l4csum_offset + sizeof(sum)) || | |
247 | skb_store_bits(skb, l4csum_offset, &sum, sizeof(sum)) < 0) | |
248 | return -1; | |
249 | ||
250 | return 0; | |
251 | } | |
252 | ||
053d20f5 PNA |
253 | static int nft_payload_csum_inet(struct sk_buff *skb, const u32 *src, |
254 | __wsum fsum, __wsum tsum, int csum_offset) | |
255 | { | |
256 | __sum16 sum; | |
257 | ||
258 | if (skb_copy_bits(skb, csum_offset, &sum, sizeof(sum)) < 0) | |
259 | return -1; | |
260 | ||
261 | nft_csum_replace(&sum, fsum, tsum); | |
262 | if (!skb_make_writable(skb, csum_offset + sizeof(sum)) || | |
263 | skb_store_bits(skb, csum_offset, &sum, sizeof(sum)) < 0) | |
264 | return -1; | |
265 | ||
266 | return 0; | |
267 | } | |
268 | ||
7ec3f7b4 PM |
269 | static void nft_payload_set_eval(const struct nft_expr *expr, |
270 | struct nft_regs *regs, | |
271 | const struct nft_pktinfo *pkt) | |
272 | { | |
273 | const struct nft_payload_set *priv = nft_expr_priv(expr); | |
274 | struct sk_buff *skb = pkt->skb; | |
275 | const u32 *src = ®s->data[priv->sreg]; | |
276 | int offset, csum_offset; | |
277 | __wsum fsum, tsum; | |
7ec3f7b4 PM |
278 | |
279 | switch (priv->base) { | |
280 | case NFT_PAYLOAD_LL_HEADER: | |
281 | if (!skb_mac_header_was_set(skb)) | |
282 | goto err; | |
283 | offset = skb_mac_header(skb) - skb->data; | |
284 | break; | |
285 | case NFT_PAYLOAD_NETWORK_HEADER: | |
286 | offset = skb_network_offset(skb); | |
287 | break; | |
288 | case NFT_PAYLOAD_TRANSPORT_HEADER: | |
a20877b5 LZ |
289 | if (!pkt->tprot_set) |
290 | goto err; | |
7ec3f7b4 PM |
291 | offset = pkt->xt.thoff; |
292 | break; | |
293 | default: | |
294 | BUG(); | |
295 | } | |
296 | ||
297 | csum_offset = offset + priv->csum_offset; | |
298 | offset += priv->offset; | |
299 | ||
053d20f5 | 300 | if ((priv->csum_type == NFT_PAYLOAD_CSUM_INET || priv->csum_flags) && |
7ec3f7b4 PM |
301 | (priv->base != NFT_PAYLOAD_TRANSPORT_HEADER || |
302 | skb->ip_summed != CHECKSUM_PARTIAL)) { | |
7ec3f7b4 PM |
303 | fsum = skb_checksum(skb, offset, priv->len, 0); |
304 | tsum = csum_partial(src, priv->len, 0); | |
7ec3f7b4 | 305 | |
053d20f5 PNA |
306 | if (priv->csum_type == NFT_PAYLOAD_CSUM_INET && |
307 | nft_payload_csum_inet(skb, src, fsum, tsum, csum_offset)) | |
7ec3f7b4 | 308 | goto err; |
18140969 PNA |
309 | |
310 | if (priv->csum_flags && | |
311 | nft_payload_l4csum_update(pkt, skb, fsum, tsum) < 0) | |
312 | goto err; | |
7ec3f7b4 PM |
313 | } |
314 | ||
315 | if (!skb_make_writable(skb, max(offset + priv->len, 0)) || | |
316 | skb_store_bits(skb, offset, src, priv->len) < 0) | |
317 | goto err; | |
318 | ||
319 | return; | |
320 | err: | |
321 | regs->verdict.code = NFT_BREAK; | |
322 | } | |
323 | ||
324 | static int nft_payload_set_init(const struct nft_ctx *ctx, | |
325 | const struct nft_expr *expr, | |
326 | const struct nlattr * const tb[]) | |
327 | { | |
328 | struct nft_payload_set *priv = nft_expr_priv(expr); | |
329 | ||
330 | priv->base = ntohl(nla_get_be32(tb[NFTA_PAYLOAD_BASE])); | |
331 | priv->offset = ntohl(nla_get_be32(tb[NFTA_PAYLOAD_OFFSET])); | |
332 | priv->len = ntohl(nla_get_be32(tb[NFTA_PAYLOAD_LEN])); | |
333 | priv->sreg = nft_parse_register(tb[NFTA_PAYLOAD_SREG]); | |
334 | ||
335 | if (tb[NFTA_PAYLOAD_CSUM_TYPE]) | |
336 | priv->csum_type = | |
337 | ntohl(nla_get_be32(tb[NFTA_PAYLOAD_CSUM_TYPE])); | |
338 | if (tb[NFTA_PAYLOAD_CSUM_OFFSET]) | |
339 | priv->csum_offset = | |
340 | ntohl(nla_get_be32(tb[NFTA_PAYLOAD_CSUM_OFFSET])); | |
18140969 PNA |
341 | if (tb[NFTA_PAYLOAD_CSUM_FLAGS]) { |
342 | u32 flags; | |
343 | ||
344 | flags = ntohl(nla_get_be32(tb[NFTA_PAYLOAD_CSUM_FLAGS])); | |
345 | if (flags & ~NFT_PAYLOAD_L4CSUM_PSEUDOHDR) | |
346 | return -EINVAL; | |
347 | ||
348 | priv->csum_flags = flags; | |
349 | } | |
7ec3f7b4 PM |
350 | |
351 | switch (priv->csum_type) { | |
352 | case NFT_PAYLOAD_CSUM_NONE: | |
353 | case NFT_PAYLOAD_CSUM_INET: | |
354 | break; | |
355 | default: | |
356 | return -EOPNOTSUPP; | |
357 | } | |
358 | ||
359 | return nft_validate_register_load(priv->sreg, priv->len); | |
360 | } | |
361 | ||
362 | static int nft_payload_set_dump(struct sk_buff *skb, const struct nft_expr *expr) | |
363 | { | |
364 | const struct nft_payload_set *priv = nft_expr_priv(expr); | |
365 | ||
366 | if (nft_dump_register(skb, NFTA_PAYLOAD_SREG, priv->sreg) || | |
367 | nla_put_be32(skb, NFTA_PAYLOAD_BASE, htonl(priv->base)) || | |
368 | nla_put_be32(skb, NFTA_PAYLOAD_OFFSET, htonl(priv->offset)) || | |
369 | nla_put_be32(skb, NFTA_PAYLOAD_LEN, htonl(priv->len)) || | |
370 | nla_put_be32(skb, NFTA_PAYLOAD_CSUM_TYPE, htonl(priv->csum_type)) || | |
371 | nla_put_be32(skb, NFTA_PAYLOAD_CSUM_OFFSET, | |
18140969 PNA |
372 | htonl(priv->csum_offset)) || |
373 | nla_put_be32(skb, NFTA_PAYLOAD_CSUM_FLAGS, htonl(priv->csum_flags))) | |
7ec3f7b4 PM |
374 | goto nla_put_failure; |
375 | return 0; | |
376 | ||
377 | nla_put_failure: | |
378 | return -1; | |
379 | } | |
380 | ||
381 | static const struct nft_expr_ops nft_payload_set_ops = { | |
382 | .type = &nft_payload_type, | |
383 | .size = NFT_EXPR_SIZE(sizeof(struct nft_payload_set)), | |
384 | .eval = nft_payload_set_eval, | |
385 | .init = nft_payload_set_init, | |
386 | .dump = nft_payload_set_dump, | |
387 | }; | |
388 | ||
0ca743a5 PNA |
389 | static const struct nft_expr_ops * |
390 | nft_payload_select_ops(const struct nft_ctx *ctx, | |
391 | const struct nlattr * const tb[]) | |
c29b72e0 PM |
392 | { |
393 | enum nft_payload_bases base; | |
394 | unsigned int offset, len; | |
395 | ||
7ec3f7b4 | 396 | if (tb[NFTA_PAYLOAD_BASE] == NULL || |
c29b72e0 PM |
397 | tb[NFTA_PAYLOAD_OFFSET] == NULL || |
398 | tb[NFTA_PAYLOAD_LEN] == NULL) | |
399 | return ERR_PTR(-EINVAL); | |
400 | ||
401 | base = ntohl(nla_get_be32(tb[NFTA_PAYLOAD_BASE])); | |
402 | switch (base) { | |
403 | case NFT_PAYLOAD_LL_HEADER: | |
404 | case NFT_PAYLOAD_NETWORK_HEADER: | |
405 | case NFT_PAYLOAD_TRANSPORT_HEADER: | |
406 | break; | |
407 | default: | |
408 | return ERR_PTR(-EOPNOTSUPP); | |
409 | } | |
410 | ||
7ec3f7b4 PM |
411 | if (tb[NFTA_PAYLOAD_SREG] != NULL) { |
412 | if (tb[NFTA_PAYLOAD_DREG] != NULL) | |
413 | return ERR_PTR(-EINVAL); | |
414 | return &nft_payload_set_ops; | |
415 | } | |
416 | ||
417 | if (tb[NFTA_PAYLOAD_DREG] == NULL) | |
418 | return ERR_PTR(-EINVAL); | |
419 | ||
c29b72e0 | 420 | offset = ntohl(nla_get_be32(tb[NFTA_PAYLOAD_OFFSET])); |
45d9bcda | 421 | len = ntohl(nla_get_be32(tb[NFTA_PAYLOAD_LEN])); |
c29b72e0 | 422 | |
f627ed91 NA |
423 | if (len <= 4 && is_power_of_2(len) && IS_ALIGNED(offset, len) && |
424 | base != NFT_PAYLOAD_LL_HEADER) | |
c29b72e0 PM |
425 | return &nft_payload_fast_ops; |
426 | else | |
427 | return &nft_payload_ops; | |
428 | } | |
429 | ||
4e24877e | 430 | struct nft_expr_type nft_payload_type __read_mostly = { |
ef1f7df9 | 431 | .name = "payload", |
c29b72e0 | 432 | .select_ops = nft_payload_select_ops, |
96518518 PM |
433 | .policy = nft_payload_policy, |
434 | .maxattr = NFTA_PAYLOAD_MAX, | |
ef1f7df9 | 435 | .owner = THIS_MODULE, |
96518518 | 436 | }; |