1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3 * Copyright (c) 2008-2009 Patrick McHardy <kaber@trash.net>
4 * Copyright (c) 2016 Pablo Neira Ayuso <pablo@netfilter.org>
5 *
6 * Development of this code funded by Astaro AG (http://www.astaro.com/)
7 */
8
9 #include <linux/kernel.h>
10 #include <linux/if_vlan.h>
11 #include <linux/init.h>
12 #include <linux/module.h>
13 #include <linux/netlink.h>
14 #include <linux/netfilter.h>
15 #include <linux/netfilter/nf_tables.h>
16 #include <net/netfilter/nf_tables_core.h>
17 #include <net/netfilter/nf_tables.h>
18 #include <net/netfilter/nf_tables_offload.h>
19 /* For layer 4 checksum field offset. */
20 #include <linux/tcp.h>
21 #include <linux/udp.h>
22 #include <linux/icmpv6.h>
23 #include <linux/ip.h>
24 #include <linux/ipv6.h>
25 #include <net/sctp/checksum.h>
26
nft_payload_rebuild_vlan_hdr(const struct sk_buff * skb,int mac_off,struct vlan_ethhdr * veth)27 static bool nft_payload_rebuild_vlan_hdr(const struct sk_buff *skb, int mac_off,
28 struct vlan_ethhdr *veth)
29 {
30 if (skb_copy_bits(skb, mac_off, veth, ETH_HLEN))
31 return false;
32
33 veth->h_vlan_proto = skb->vlan_proto;
34 veth->h_vlan_TCI = htons(skb_vlan_tag_get(skb));
35 veth->h_vlan_encapsulated_proto = skb->protocol;
36
37 return true;
38 }
39
40 /* add vlan header into the user buffer for if tag was removed by offloads */
41 static bool
nft_payload_copy_vlan(u32 * d,const struct sk_buff * skb,u8 offset,u8 len)42 nft_payload_copy_vlan(u32 *d, const struct sk_buff *skb, u8 offset, u8 len)
43 {
44 int mac_off = skb_mac_header(skb) - skb->data;
45 u8 *vlanh, *dst_u8 = (u8 *) d;
46 struct vlan_ethhdr veth;
47 u8 vlan_hlen = 0;
48
49 if ((skb->protocol == htons(ETH_P_8021AD) ||
50 skb->protocol == htons(ETH_P_8021Q)) &&
51 offset >= VLAN_ETH_HLEN && offset < VLAN_ETH_HLEN + VLAN_HLEN)
52 vlan_hlen += VLAN_HLEN;
53
54 vlanh = (u8 *) &veth;
55 if (offset < VLAN_ETH_HLEN + vlan_hlen) {
56 u8 ethlen = len;
57
58 if (vlan_hlen &&
59 skb_copy_bits(skb, mac_off, &veth, VLAN_ETH_HLEN) < 0)
60 return false;
61 else if (!nft_payload_rebuild_vlan_hdr(skb, mac_off, &veth))
62 return false;
63
64 if (offset + len > VLAN_ETH_HLEN + vlan_hlen)
65 ethlen -= offset + len - VLAN_ETH_HLEN + vlan_hlen;
66
67 memcpy(dst_u8, vlanh + offset - vlan_hlen, ethlen);
68
69 len -= ethlen;
70 if (len == 0)
71 return true;
72
73 dst_u8 += ethlen;
74 offset = ETH_HLEN + vlan_hlen;
75 } else {
76 offset -= VLAN_HLEN + vlan_hlen;
77 }
78
79 return skb_copy_bits(skb, offset + mac_off, dst_u8, len) == 0;
80 }
81
nft_payload_eval(const struct nft_expr * expr,struct nft_regs * regs,const struct nft_pktinfo * pkt)82 void nft_payload_eval(const struct nft_expr *expr,
83 struct nft_regs *regs,
84 const struct nft_pktinfo *pkt)
85 {
86 const struct nft_payload *priv = nft_expr_priv(expr);
87 const struct sk_buff *skb = pkt->skb;
88 u32 *dest = ®s->data[priv->dreg];
89 int offset;
90
91 if (priv->len % NFT_REG32_SIZE)
92 dest[priv->len / NFT_REG32_SIZE] = 0;
93
94 switch (priv->base) {
95 case NFT_PAYLOAD_LL_HEADER:
96 if (!skb_mac_header_was_set(skb))
97 goto err;
98
99 if (skb_vlan_tag_present(skb)) {
100 if (!nft_payload_copy_vlan(dest, skb,
101 priv->offset, priv->len))
102 goto err;
103 return;
104 }
105 offset = skb_mac_header(skb) - skb->data;
106 break;
107 case NFT_PAYLOAD_NETWORK_HEADER:
108 offset = skb_network_offset(skb);
109 break;
110 case NFT_PAYLOAD_TRANSPORT_HEADER:
111 if (!pkt->tprot_set)
112 goto err;
113 offset = pkt->xt.thoff;
114 break;
115 default:
116 BUG();
117 }
118 offset += priv->offset;
119
120 if (skb_copy_bits(skb, offset, dest, priv->len) < 0)
121 goto err;
122 return;
123 err:
124 regs->verdict.code = NFT_BREAK;
125 }
126
127 static const struct nla_policy nft_payload_policy[NFTA_PAYLOAD_MAX + 1] = {
128 [NFTA_PAYLOAD_SREG] = { .type = NLA_U32 },
129 [NFTA_PAYLOAD_DREG] = { .type = NLA_U32 },
130 [NFTA_PAYLOAD_BASE] = { .type = NLA_U32 },
131 [NFTA_PAYLOAD_OFFSET] = { .type = NLA_U32 },
132 [NFTA_PAYLOAD_LEN] = { .type = NLA_U32 },
133 [NFTA_PAYLOAD_CSUM_TYPE] = { .type = NLA_U32 },
134 [NFTA_PAYLOAD_CSUM_OFFSET] = { .type = NLA_U32 },
135 [NFTA_PAYLOAD_CSUM_FLAGS] = { .type = NLA_U32 },
136 };
137
nft_payload_init(const struct nft_ctx * ctx,const struct nft_expr * expr,const struct nlattr * const tb[])138 static int nft_payload_init(const struct nft_ctx *ctx,
139 const struct nft_expr *expr,
140 const struct nlattr * const tb[])
141 {
142 struct nft_payload *priv = nft_expr_priv(expr);
143
144 priv->base = ntohl(nla_get_be32(tb[NFTA_PAYLOAD_BASE]));
145 priv->offset = ntohl(nla_get_be32(tb[NFTA_PAYLOAD_OFFSET]));
146 priv->len = ntohl(nla_get_be32(tb[NFTA_PAYLOAD_LEN]));
147
148 return nft_parse_register_store(ctx, tb[NFTA_PAYLOAD_DREG],
149 &priv->dreg, NULL, NFT_DATA_VALUE,
150 priv->len);
151 }
152
nft_payload_dump(struct sk_buff * skb,const struct nft_expr * expr)153 static int nft_payload_dump(struct sk_buff *skb, const struct nft_expr *expr)
154 {
155 const struct nft_payload *priv = nft_expr_priv(expr);
156
157 if (nft_dump_register(skb, NFTA_PAYLOAD_DREG, priv->dreg) ||
158 nla_put_be32(skb, NFTA_PAYLOAD_BASE, htonl(priv->base)) ||
159 nla_put_be32(skb, NFTA_PAYLOAD_OFFSET, htonl(priv->offset)) ||
160 nla_put_be32(skb, NFTA_PAYLOAD_LEN, htonl(priv->len)))
161 goto nla_put_failure;
162 return 0;
163
164 nla_put_failure:
165 return -1;
166 }
167
nft_payload_offload_mask(struct nft_offload_reg * reg,u32 priv_len,u32 field_len)168 static bool nft_payload_offload_mask(struct nft_offload_reg *reg,
169 u32 priv_len, u32 field_len)
170 {
171 unsigned int remainder, delta, k;
172 struct nft_data mask = {};
173 __be32 remainder_mask;
174
175 if (priv_len == field_len) {
176 memset(®->mask, 0xff, priv_len);
177 return true;
178 } else if (priv_len > field_len) {
179 return false;
180 }
181
182 memset(&mask, 0xff, field_len);
183 remainder = priv_len % sizeof(u32);
184 if (remainder) {
185 k = priv_len / sizeof(u32);
186 delta = field_len - priv_len;
187 remainder_mask = htonl(~((1 << (delta * BITS_PER_BYTE)) - 1));
188 mask.data[k] = (__force u32)remainder_mask;
189 }
190
191 memcpy(®->mask, &mask, field_len);
192
193 return true;
194 }
195
nft_payload_offload_ll(struct nft_offload_ctx * ctx,struct nft_flow_rule * flow,const struct nft_payload * priv)196 static int nft_payload_offload_ll(struct nft_offload_ctx *ctx,
197 struct nft_flow_rule *flow,
198 const struct nft_payload *priv)
199 {
200 struct nft_offload_reg *reg = &ctx->regs[priv->dreg];
201
202 switch (priv->offset) {
203 case offsetof(struct ethhdr, h_source):
204 if (!nft_payload_offload_mask(reg, priv->len, ETH_ALEN))
205 return -EOPNOTSUPP;
206
207 NFT_OFFLOAD_MATCH(FLOW_DISSECTOR_KEY_ETH_ADDRS, eth_addrs,
208 src, ETH_ALEN, reg);
209 break;
210 case offsetof(struct ethhdr, h_dest):
211 if (!nft_payload_offload_mask(reg, priv->len, ETH_ALEN))
212 return -EOPNOTSUPP;
213
214 NFT_OFFLOAD_MATCH(FLOW_DISSECTOR_KEY_ETH_ADDRS, eth_addrs,
215 dst, ETH_ALEN, reg);
216 break;
217 case offsetof(struct ethhdr, h_proto):
218 if (!nft_payload_offload_mask(reg, priv->len, sizeof(__be16)))
219 return -EOPNOTSUPP;
220
221 NFT_OFFLOAD_MATCH(FLOW_DISSECTOR_KEY_BASIC, basic,
222 n_proto, sizeof(__be16), reg);
223 nft_offload_set_dependency(ctx, NFT_OFFLOAD_DEP_NETWORK);
224 break;
225 case offsetof(struct vlan_ethhdr, h_vlan_TCI):
226 if (!nft_payload_offload_mask(reg, priv->len, sizeof(__be16)))
227 return -EOPNOTSUPP;
228
229 NFT_OFFLOAD_MATCH_FLAGS(FLOW_DISSECTOR_KEY_VLAN, vlan,
230 vlan_tci, sizeof(__be16), reg,
231 NFT_OFFLOAD_F_NETWORK2HOST);
232 break;
233 case offsetof(struct vlan_ethhdr, h_vlan_encapsulated_proto):
234 if (!nft_payload_offload_mask(reg, priv->len, sizeof(__be16)))
235 return -EOPNOTSUPP;
236
237 NFT_OFFLOAD_MATCH(FLOW_DISSECTOR_KEY_VLAN, vlan,
238 vlan_tpid, sizeof(__be16), reg);
239 nft_offload_set_dependency(ctx, NFT_OFFLOAD_DEP_NETWORK);
240 break;
241 case offsetof(struct vlan_ethhdr, h_vlan_TCI) + sizeof(struct vlan_hdr):
242 if (!nft_payload_offload_mask(reg, priv->len, sizeof(__be16)))
243 return -EOPNOTSUPP;
244
245 NFT_OFFLOAD_MATCH_FLAGS(FLOW_DISSECTOR_KEY_CVLAN, cvlan,
246 vlan_tci, sizeof(__be16), reg,
247 NFT_OFFLOAD_F_NETWORK2HOST);
248 break;
249 case offsetof(struct vlan_ethhdr, h_vlan_encapsulated_proto) +
250 sizeof(struct vlan_hdr):
251 if (!nft_payload_offload_mask(reg, priv->len, sizeof(__be16)))
252 return -EOPNOTSUPP;
253
254 NFT_OFFLOAD_MATCH(FLOW_DISSECTOR_KEY_CVLAN, cvlan,
255 vlan_tpid, sizeof(__be16), reg);
256 nft_offload_set_dependency(ctx, NFT_OFFLOAD_DEP_NETWORK);
257 break;
258 default:
259 return -EOPNOTSUPP;
260 }
261
262 return 0;
263 }
264
nft_payload_offload_ip(struct nft_offload_ctx * ctx,struct nft_flow_rule * flow,const struct nft_payload * priv)265 static int nft_payload_offload_ip(struct nft_offload_ctx *ctx,
266 struct nft_flow_rule *flow,
267 const struct nft_payload *priv)
268 {
269 struct nft_offload_reg *reg = &ctx->regs[priv->dreg];
270
271 switch (priv->offset) {
272 case offsetof(struct iphdr, saddr):
273 if (!nft_payload_offload_mask(reg, priv->len,
274 sizeof(struct in_addr)))
275 return -EOPNOTSUPP;
276
277 NFT_OFFLOAD_MATCH(FLOW_DISSECTOR_KEY_IPV4_ADDRS, ipv4, src,
278 sizeof(struct in_addr), reg);
279 nft_flow_rule_set_addr_type(flow, FLOW_DISSECTOR_KEY_IPV4_ADDRS);
280 break;
281 case offsetof(struct iphdr, daddr):
282 if (!nft_payload_offload_mask(reg, priv->len,
283 sizeof(struct in_addr)))
284 return -EOPNOTSUPP;
285
286 NFT_OFFLOAD_MATCH(FLOW_DISSECTOR_KEY_IPV4_ADDRS, ipv4, dst,
287 sizeof(struct in_addr), reg);
288 nft_flow_rule_set_addr_type(flow, FLOW_DISSECTOR_KEY_IPV4_ADDRS);
289 break;
290 case offsetof(struct iphdr, protocol):
291 if (!nft_payload_offload_mask(reg, priv->len, sizeof(__u8)))
292 return -EOPNOTSUPP;
293
294 NFT_OFFLOAD_MATCH(FLOW_DISSECTOR_KEY_BASIC, basic, ip_proto,
295 sizeof(__u8), reg);
296 nft_offload_set_dependency(ctx, NFT_OFFLOAD_DEP_TRANSPORT);
297 break;
298 default:
299 return -EOPNOTSUPP;
300 }
301
302 return 0;
303 }
304
nft_payload_offload_ip6(struct nft_offload_ctx * ctx,struct nft_flow_rule * flow,const struct nft_payload * priv)305 static int nft_payload_offload_ip6(struct nft_offload_ctx *ctx,
306 struct nft_flow_rule *flow,
307 const struct nft_payload *priv)
308 {
309 struct nft_offload_reg *reg = &ctx->regs[priv->dreg];
310
311 switch (priv->offset) {
312 case offsetof(struct ipv6hdr, saddr):
313 if (!nft_payload_offload_mask(reg, priv->len,
314 sizeof(struct in6_addr)))
315 return -EOPNOTSUPP;
316
317 NFT_OFFLOAD_MATCH(FLOW_DISSECTOR_KEY_IPV6_ADDRS, ipv6, src,
318 sizeof(struct in6_addr), reg);
319 nft_flow_rule_set_addr_type(flow, FLOW_DISSECTOR_KEY_IPV6_ADDRS);
320 break;
321 case offsetof(struct ipv6hdr, daddr):
322 if (!nft_payload_offload_mask(reg, priv->len,
323 sizeof(struct in6_addr)))
324 return -EOPNOTSUPP;
325
326 NFT_OFFLOAD_MATCH(FLOW_DISSECTOR_KEY_IPV6_ADDRS, ipv6, dst,
327 sizeof(struct in6_addr), reg);
328 nft_flow_rule_set_addr_type(flow, FLOW_DISSECTOR_KEY_IPV6_ADDRS);
329 break;
330 case offsetof(struct ipv6hdr, nexthdr):
331 if (!nft_payload_offload_mask(reg, priv->len, sizeof(__u8)))
332 return -EOPNOTSUPP;
333
334 NFT_OFFLOAD_MATCH(FLOW_DISSECTOR_KEY_BASIC, basic, ip_proto,
335 sizeof(__u8), reg);
336 nft_offload_set_dependency(ctx, NFT_OFFLOAD_DEP_TRANSPORT);
337 break;
338 default:
339 return -EOPNOTSUPP;
340 }
341
342 return 0;
343 }
344
nft_payload_offload_nh(struct nft_offload_ctx * ctx,struct nft_flow_rule * flow,const struct nft_payload * priv)345 static int nft_payload_offload_nh(struct nft_offload_ctx *ctx,
346 struct nft_flow_rule *flow,
347 const struct nft_payload *priv)
348 {
349 int err;
350
351 switch (ctx->dep.l3num) {
352 case htons(ETH_P_IP):
353 err = nft_payload_offload_ip(ctx, flow, priv);
354 break;
355 case htons(ETH_P_IPV6):
356 err = nft_payload_offload_ip6(ctx, flow, priv);
357 break;
358 default:
359 return -EOPNOTSUPP;
360 }
361
362 return err;
363 }
364
nft_payload_offload_tcp(struct nft_offload_ctx * ctx,struct nft_flow_rule * flow,const struct nft_payload * priv)365 static int nft_payload_offload_tcp(struct nft_offload_ctx *ctx,
366 struct nft_flow_rule *flow,
367 const struct nft_payload *priv)
368 {
369 struct nft_offload_reg *reg = &ctx->regs[priv->dreg];
370
371 switch (priv->offset) {
372 case offsetof(struct tcphdr, source):
373 if (!nft_payload_offload_mask(reg, priv->len, sizeof(__be16)))
374 return -EOPNOTSUPP;
375
376 NFT_OFFLOAD_MATCH(FLOW_DISSECTOR_KEY_PORTS, tp, src,
377 sizeof(__be16), reg);
378 break;
379 case offsetof(struct tcphdr, dest):
380 if (!nft_payload_offload_mask(reg, priv->len, sizeof(__be16)))
381 return -EOPNOTSUPP;
382
383 NFT_OFFLOAD_MATCH(FLOW_DISSECTOR_KEY_PORTS, tp, dst,
384 sizeof(__be16), reg);
385 break;
386 default:
387 return -EOPNOTSUPP;
388 }
389
390 return 0;
391 }
392
nft_payload_offload_udp(struct nft_offload_ctx * ctx,struct nft_flow_rule * flow,const struct nft_payload * priv)393 static int nft_payload_offload_udp(struct nft_offload_ctx *ctx,
394 struct nft_flow_rule *flow,
395 const struct nft_payload *priv)
396 {
397 struct nft_offload_reg *reg = &ctx->regs[priv->dreg];
398
399 switch (priv->offset) {
400 case offsetof(struct udphdr, source):
401 if (!nft_payload_offload_mask(reg, priv->len, sizeof(__be16)))
402 return -EOPNOTSUPP;
403
404 NFT_OFFLOAD_MATCH(FLOW_DISSECTOR_KEY_PORTS, tp, src,
405 sizeof(__be16), reg);
406 break;
407 case offsetof(struct udphdr, dest):
408 if (!nft_payload_offload_mask(reg, priv->len, sizeof(__be16)))
409 return -EOPNOTSUPP;
410
411 NFT_OFFLOAD_MATCH(FLOW_DISSECTOR_KEY_PORTS, tp, dst,
412 sizeof(__be16), reg);
413 break;
414 default:
415 return -EOPNOTSUPP;
416 }
417
418 return 0;
419 }
420
nft_payload_offload_th(struct nft_offload_ctx * ctx,struct nft_flow_rule * flow,const struct nft_payload * priv)421 static int nft_payload_offload_th(struct nft_offload_ctx *ctx,
422 struct nft_flow_rule *flow,
423 const struct nft_payload *priv)
424 {
425 int err;
426
427 switch (ctx->dep.protonum) {
428 case IPPROTO_TCP:
429 err = nft_payload_offload_tcp(ctx, flow, priv);
430 break;
431 case IPPROTO_UDP:
432 err = nft_payload_offload_udp(ctx, flow, priv);
433 break;
434 default:
435 return -EOPNOTSUPP;
436 }
437
438 return err;
439 }
440
nft_payload_offload(struct nft_offload_ctx * ctx,struct nft_flow_rule * flow,const struct nft_expr * expr)441 static int nft_payload_offload(struct nft_offload_ctx *ctx,
442 struct nft_flow_rule *flow,
443 const struct nft_expr *expr)
444 {
445 const struct nft_payload *priv = nft_expr_priv(expr);
446 int err;
447
448 switch (priv->base) {
449 case NFT_PAYLOAD_LL_HEADER:
450 err = nft_payload_offload_ll(ctx, flow, priv);
451 break;
452 case NFT_PAYLOAD_NETWORK_HEADER:
453 err = nft_payload_offload_nh(ctx, flow, priv);
454 break;
455 case NFT_PAYLOAD_TRANSPORT_HEADER:
456 err = nft_payload_offload_th(ctx, flow, priv);
457 break;
458 default:
459 err = -EOPNOTSUPP;
460 break;
461 }
462 return err;
463 }
464
465 static const struct nft_expr_ops nft_payload_ops = {
466 .type = &nft_payload_type,
467 .size = NFT_EXPR_SIZE(sizeof(struct nft_payload)),
468 .eval = nft_payload_eval,
469 .init = nft_payload_init,
470 .dump = nft_payload_dump,
471 .offload = nft_payload_offload,
472 };
473
474 const struct nft_expr_ops nft_payload_fast_ops = {
475 .type = &nft_payload_type,
476 .size = NFT_EXPR_SIZE(sizeof(struct nft_payload)),
477 .eval = nft_payload_eval,
478 .init = nft_payload_init,
479 .dump = nft_payload_dump,
480 .offload = nft_payload_offload,
481 };
482
nft_csum_replace(__sum16 * sum,__wsum fsum,__wsum tsum)483 static inline void nft_csum_replace(__sum16 *sum, __wsum fsum, __wsum tsum)
484 {
485 *sum = csum_fold(csum_add(csum_sub(~csum_unfold(*sum), fsum), tsum));
486 if (*sum == 0)
487 *sum = CSUM_MANGLED_0;
488 }
489
nft_payload_udp_checksum(struct sk_buff * skb,unsigned int thoff)490 static bool nft_payload_udp_checksum(struct sk_buff *skb, unsigned int thoff)
491 {
492 struct udphdr *uh, _uh;
493
494 uh = skb_header_pointer(skb, thoff, sizeof(_uh), &_uh);
495 if (!uh)
496 return false;
497
498 return (__force bool)uh->check;
499 }
500
nft_payload_l4csum_offset(const struct nft_pktinfo * pkt,struct sk_buff * skb,unsigned int * l4csum_offset)501 static int nft_payload_l4csum_offset(const struct nft_pktinfo *pkt,
502 struct sk_buff *skb,
503 unsigned int *l4csum_offset)
504 {
505 switch (pkt->tprot) {
506 case IPPROTO_TCP:
507 *l4csum_offset = offsetof(struct tcphdr, check);
508 break;
509 case IPPROTO_UDP:
510 if (!nft_payload_udp_checksum(skb, pkt->xt.thoff))
511 return -1;
512 fallthrough;
513 case IPPROTO_UDPLITE:
514 *l4csum_offset = offsetof(struct udphdr, check);
515 break;
516 case IPPROTO_ICMPV6:
517 *l4csum_offset = offsetof(struct icmp6hdr, icmp6_cksum);
518 break;
519 default:
520 return -1;
521 }
522
523 *l4csum_offset += pkt->xt.thoff;
524 return 0;
525 }
526
nft_payload_csum_sctp(struct sk_buff * skb,int offset)527 static int nft_payload_csum_sctp(struct sk_buff *skb, int offset)
528 {
529 struct sctphdr *sh;
530
531 if (skb_ensure_writable(skb, offset + sizeof(*sh)))
532 return -1;
533
534 sh = (struct sctphdr *)(skb->data + offset);
535 sh->checksum = sctp_compute_cksum(skb, offset);
536 skb->ip_summed = CHECKSUM_UNNECESSARY;
537 return 0;
538 }
539
nft_payload_l4csum_update(const struct nft_pktinfo * pkt,struct sk_buff * skb,__wsum fsum,__wsum tsum)540 static int nft_payload_l4csum_update(const struct nft_pktinfo *pkt,
541 struct sk_buff *skb,
542 __wsum fsum, __wsum tsum)
543 {
544 int l4csum_offset;
545 __sum16 sum;
546
547 /* If we cannot determine layer 4 checksum offset or this packet doesn't
548 * require layer 4 checksum recalculation, skip this packet.
549 */
550 if (nft_payload_l4csum_offset(pkt, skb, &l4csum_offset) < 0)
551 return 0;
552
553 if (skb_copy_bits(skb, l4csum_offset, &sum, sizeof(sum)) < 0)
554 return -1;
555
556 /* Checksum mangling for an arbitrary amount of bytes, based on
557 * inet_proto_csum_replace*() functions.
558 */
559 if (skb->ip_summed != CHECKSUM_PARTIAL) {
560 nft_csum_replace(&sum, fsum, tsum);
561 if (skb->ip_summed == CHECKSUM_COMPLETE) {
562 skb->csum = ~csum_add(csum_sub(~(skb->csum), fsum),
563 tsum);
564 }
565 } else {
566 sum = ~csum_fold(csum_add(csum_sub(csum_unfold(sum), fsum),
567 tsum));
568 }
569
570 if (skb_ensure_writable(skb, l4csum_offset + sizeof(sum)) ||
571 skb_store_bits(skb, l4csum_offset, &sum, sizeof(sum)) < 0)
572 return -1;
573
574 return 0;
575 }
576
nft_payload_csum_inet(struct sk_buff * skb,const u32 * src,__wsum fsum,__wsum tsum,int csum_offset)577 static int nft_payload_csum_inet(struct sk_buff *skb, const u32 *src,
578 __wsum fsum, __wsum tsum, int csum_offset)
579 {
580 __sum16 sum;
581
582 if (skb_copy_bits(skb, csum_offset, &sum, sizeof(sum)) < 0)
583 return -1;
584
585 nft_csum_replace(&sum, fsum, tsum);
586 if (skb_ensure_writable(skb, csum_offset + sizeof(sum)) ||
587 skb_store_bits(skb, csum_offset, &sum, sizeof(sum)) < 0)
588 return -1;
589
590 return 0;
591 }
592
nft_payload_set_eval(const struct nft_expr * expr,struct nft_regs * regs,const struct nft_pktinfo * pkt)593 static void nft_payload_set_eval(const struct nft_expr *expr,
594 struct nft_regs *regs,
595 const struct nft_pktinfo *pkt)
596 {
597 const struct nft_payload_set *priv = nft_expr_priv(expr);
598 struct sk_buff *skb = pkt->skb;
599 const u32 *src = ®s->data[priv->sreg];
600 int offset, csum_offset;
601 __wsum fsum, tsum;
602
603 switch (priv->base) {
604 case NFT_PAYLOAD_LL_HEADER:
605 if (!skb_mac_header_was_set(skb))
606 goto err;
607 offset = skb_mac_header(skb) - skb->data;
608 break;
609 case NFT_PAYLOAD_NETWORK_HEADER:
610 offset = skb_network_offset(skb);
611 break;
612 case NFT_PAYLOAD_TRANSPORT_HEADER:
613 if (!pkt->tprot_set)
614 goto err;
615 offset = pkt->xt.thoff;
616 break;
617 default:
618 BUG();
619 }
620
621 csum_offset = offset + priv->csum_offset;
622 offset += priv->offset;
623
624 if ((priv->csum_type == NFT_PAYLOAD_CSUM_INET || priv->csum_flags) &&
625 (priv->base != NFT_PAYLOAD_TRANSPORT_HEADER ||
626 skb->ip_summed != CHECKSUM_PARTIAL)) {
627 fsum = skb_checksum(skb, offset, priv->len, 0);
628 tsum = csum_partial(src, priv->len, 0);
629
630 if (priv->csum_type == NFT_PAYLOAD_CSUM_INET &&
631 nft_payload_csum_inet(skb, src, fsum, tsum, csum_offset))
632 goto err;
633
634 if (priv->csum_flags &&
635 nft_payload_l4csum_update(pkt, skb, fsum, tsum) < 0)
636 goto err;
637 }
638
639 if (skb_ensure_writable(skb, max(offset + priv->len, 0)) ||
640 skb_store_bits(skb, offset, src, priv->len) < 0)
641 goto err;
642
643 if (priv->csum_type == NFT_PAYLOAD_CSUM_SCTP &&
644 pkt->tprot == IPPROTO_SCTP &&
645 skb->ip_summed != CHECKSUM_PARTIAL) {
646 if (nft_payload_csum_sctp(skb, pkt->xt.thoff))
647 goto err;
648 }
649
650 return;
651 err:
652 regs->verdict.code = NFT_BREAK;
653 }
654
nft_payload_set_init(const struct nft_ctx * ctx,const struct nft_expr * expr,const struct nlattr * const tb[])655 static int nft_payload_set_init(const struct nft_ctx *ctx,
656 const struct nft_expr *expr,
657 const struct nlattr * const tb[])
658 {
659 struct nft_payload_set *priv = nft_expr_priv(expr);
660
661 priv->base = ntohl(nla_get_be32(tb[NFTA_PAYLOAD_BASE]));
662 priv->offset = ntohl(nla_get_be32(tb[NFTA_PAYLOAD_OFFSET]));
663 priv->len = ntohl(nla_get_be32(tb[NFTA_PAYLOAD_LEN]));
664
665 if (tb[NFTA_PAYLOAD_CSUM_TYPE])
666 priv->csum_type =
667 ntohl(nla_get_be32(tb[NFTA_PAYLOAD_CSUM_TYPE]));
668 if (tb[NFTA_PAYLOAD_CSUM_OFFSET])
669 priv->csum_offset =
670 ntohl(nla_get_be32(tb[NFTA_PAYLOAD_CSUM_OFFSET]));
671 if (tb[NFTA_PAYLOAD_CSUM_FLAGS]) {
672 u32 flags;
673
674 flags = ntohl(nla_get_be32(tb[NFTA_PAYLOAD_CSUM_FLAGS]));
675 if (flags & ~NFT_PAYLOAD_L4CSUM_PSEUDOHDR)
676 return -EINVAL;
677
678 priv->csum_flags = flags;
679 }
680
681 switch (priv->csum_type) {
682 case NFT_PAYLOAD_CSUM_NONE:
683 case NFT_PAYLOAD_CSUM_INET:
684 break;
685 case NFT_PAYLOAD_CSUM_SCTP:
686 if (priv->base != NFT_PAYLOAD_TRANSPORT_HEADER)
687 return -EINVAL;
688
689 if (priv->csum_offset != offsetof(struct sctphdr, checksum))
690 return -EINVAL;
691 break;
692 default:
693 return -EOPNOTSUPP;
694 }
695
696 return nft_parse_register_load(tb[NFTA_PAYLOAD_SREG], &priv->sreg,
697 priv->len);
698 }
699
nft_payload_set_dump(struct sk_buff * skb,const struct nft_expr * expr)700 static int nft_payload_set_dump(struct sk_buff *skb, const struct nft_expr *expr)
701 {
702 const struct nft_payload_set *priv = nft_expr_priv(expr);
703
704 if (nft_dump_register(skb, NFTA_PAYLOAD_SREG, priv->sreg) ||
705 nla_put_be32(skb, NFTA_PAYLOAD_BASE, htonl(priv->base)) ||
706 nla_put_be32(skb, NFTA_PAYLOAD_OFFSET, htonl(priv->offset)) ||
707 nla_put_be32(skb, NFTA_PAYLOAD_LEN, htonl(priv->len)) ||
708 nla_put_be32(skb, NFTA_PAYLOAD_CSUM_TYPE, htonl(priv->csum_type)) ||
709 nla_put_be32(skb, NFTA_PAYLOAD_CSUM_OFFSET,
710 htonl(priv->csum_offset)) ||
711 nla_put_be32(skb, NFTA_PAYLOAD_CSUM_FLAGS, htonl(priv->csum_flags)))
712 goto nla_put_failure;
713 return 0;
714
715 nla_put_failure:
716 return -1;
717 }
718
719 static const struct nft_expr_ops nft_payload_set_ops = {
720 .type = &nft_payload_type,
721 .size = NFT_EXPR_SIZE(sizeof(struct nft_payload_set)),
722 .eval = nft_payload_set_eval,
723 .init = nft_payload_set_init,
724 .dump = nft_payload_set_dump,
725 };
726
727 static const struct nft_expr_ops *
nft_payload_select_ops(const struct nft_ctx * ctx,const struct nlattr * const tb[])728 nft_payload_select_ops(const struct nft_ctx *ctx,
729 const struct nlattr * const tb[])
730 {
731 enum nft_payload_bases base;
732 unsigned int offset, len;
733
734 if (tb[NFTA_PAYLOAD_BASE] == NULL ||
735 tb[NFTA_PAYLOAD_OFFSET] == NULL ||
736 tb[NFTA_PAYLOAD_LEN] == NULL)
737 return ERR_PTR(-EINVAL);
738
739 base = ntohl(nla_get_be32(tb[NFTA_PAYLOAD_BASE]));
740 switch (base) {
741 case NFT_PAYLOAD_LL_HEADER:
742 case NFT_PAYLOAD_NETWORK_HEADER:
743 case NFT_PAYLOAD_TRANSPORT_HEADER:
744 break;
745 default:
746 return ERR_PTR(-EOPNOTSUPP);
747 }
748
749 if (tb[NFTA_PAYLOAD_SREG] != NULL) {
750 if (tb[NFTA_PAYLOAD_DREG] != NULL)
751 return ERR_PTR(-EINVAL);
752 return &nft_payload_set_ops;
753 }
754
755 if (tb[NFTA_PAYLOAD_DREG] == NULL)
756 return ERR_PTR(-EINVAL);
757
758 offset = ntohl(nla_get_be32(tb[NFTA_PAYLOAD_OFFSET]));
759 len = ntohl(nla_get_be32(tb[NFTA_PAYLOAD_LEN]));
760
761 if (len <= 4 && is_power_of_2(len) && IS_ALIGNED(offset, len) &&
762 base != NFT_PAYLOAD_LL_HEADER)
763 return &nft_payload_fast_ops;
764 else
765 return &nft_payload_ops;
766 }
767
768 struct nft_expr_type nft_payload_type __read_mostly = {
769 .name = "payload",
770 .select_ops = nft_payload_select_ops,
771 .policy = nft_payload_policy,
772 .maxattr = NFTA_PAYLOAD_MAX,
773 .owner = THIS_MODULE,
774 };
775