1 #define pr_fmt(fmt) "IPsec: " fmt
3 #include <crypto/hash.h>
5 #include <linux/module.h>
6 #include <linux/slab.h>
10 #include <linux/crypto.h>
11 #include <linux/pfkeyv2.h>
12 #include <linux/scatterlist.h>
14 #include <net/protocol.h>
17 struct xfrm_skb_cb xfrm;
21 #define AH_SKB_CB(__skb) ((struct ah_skb_cb *)&((__skb)->cb[0]))
23 static void *ah_alloc_tmp(struct crypto_ahash *ahash, int nfrags,
28 len = size + crypto_ahash_digestsize(ahash) +
29 (crypto_ahash_alignmask(ahash) &
30 ~(crypto_tfm_ctx_alignment() - 1));
32 len = ALIGN(len, crypto_tfm_ctx_alignment());
34 len += sizeof(struct ahash_request) + crypto_ahash_reqsize(ahash);
35 len = ALIGN(len, __alignof__(struct scatterlist));
37 len += sizeof(struct scatterlist) * nfrags;
39 return kmalloc(len, GFP_ATOMIC);
42 static inline u8 *ah_tmp_auth(void *tmp, unsigned int offset)
47 static inline u8 *ah_tmp_icv(struct crypto_ahash *ahash, void *tmp,
50 return PTR_ALIGN((u8 *)tmp + offset, crypto_ahash_alignmask(ahash) + 1);
53 static inline struct ahash_request *ah_tmp_req(struct crypto_ahash *ahash,
56 struct ahash_request *req;
58 req = (void *)PTR_ALIGN(icv + crypto_ahash_digestsize(ahash),
59 crypto_tfm_ctx_alignment());
61 ahash_request_set_tfm(req, ahash);
66 static inline struct scatterlist *ah_req_sg(struct crypto_ahash *ahash,
67 struct ahash_request *req)
69 return (void *)ALIGN((unsigned long)(req + 1) +
70 crypto_ahash_reqsize(ahash),
71 __alignof__(struct scatterlist));
74 /* Clear mutable options and find final destination to substitute
75 * into IP header for icv calculation. Options are already checked
76 * for validity, so paranoia is not required. */
78 static int ip_clear_mutable_options(const struct iphdr *iph, __be32 *daddr)
80 unsigned char *optptr = (unsigned char *)(iph+1);
81 int l = iph->ihl*4 - sizeof(struct iphdr);
94 if (optlen<2 || optlen>l)
98 case 0x85: /* Some "Extended Security" crap. */
101 case 0x80|21: /* RFC1770 */
107 memcpy(daddr, optptr+optlen-4, 4);
110 memset(optptr, 0, optlen);
118 static void ah_output_done(struct crypto_async_request *base, int err)
122 struct sk_buff *skb = base->data;
123 struct xfrm_state *x = skb_dst(skb)->xfrm;
124 struct ah_data *ahp = x->data;
125 struct iphdr *top_iph = ip_hdr(skb);
126 struct ip_auth_hdr *ah = ip_auth_hdr(skb);
127 int ihl = ip_hdrlen(skb);
129 iph = AH_SKB_CB(skb)->tmp;
130 icv = ah_tmp_icv(ahp->ahash, iph, ihl);
131 memcpy(ah->auth_data, icv, ahp->icv_trunc_len);
133 top_iph->tos = iph->tos;
134 top_iph->ttl = iph->ttl;
135 top_iph->frag_off = iph->frag_off;
136 if (top_iph->ihl != 5) {
137 top_iph->daddr = iph->daddr;
138 memcpy(top_iph+1, iph+1, top_iph->ihl*4 - sizeof(struct iphdr));
141 kfree(AH_SKB_CB(skb)->tmp);
142 xfrm_output_resume(skb, err);
145 static int ah_output(struct xfrm_state *x, struct sk_buff *skb)
151 struct sk_buff *trailer;
152 struct crypto_ahash *ahash;
153 struct ahash_request *req;
154 struct scatterlist *sg;
155 struct iphdr *iph, *top_iph;
156 struct ip_auth_hdr *ah;
161 struct scatterlist *seqhisg;
166 if ((err = skb_cow_data(skb, 0, &trailer)) < 0)
170 skb_push(skb, -skb_network_offset(skb));
171 ah = ip_auth_hdr(skb);
172 ihl = ip_hdrlen(skb);
174 if (x->props.flags & XFRM_STATE_ESN) {
176 seqhi_len = sizeof(*seqhi);
179 iph = ah_alloc_tmp(ahash, nfrags + sglists, ihl + seqhi_len);
182 seqhi = (__be32 *)((char *)iph + ihl);
183 icv = ah_tmp_icv(ahash, seqhi, seqhi_len);
184 req = ah_tmp_req(ahash, icv);
185 sg = ah_req_sg(ahash, req);
186 seqhisg = sg + nfrags;
188 memset(ah->auth_data, 0, ahp->icv_trunc_len);
190 top_iph = ip_hdr(skb);
192 iph->tos = top_iph->tos;
193 iph->ttl = top_iph->ttl;
194 iph->frag_off = top_iph->frag_off;
196 if (top_iph->ihl != 5) {
197 iph->daddr = top_iph->daddr;
198 memcpy(iph+1, top_iph+1, top_iph->ihl*4 - sizeof(struct iphdr));
199 err = ip_clear_mutable_options(top_iph, &top_iph->daddr);
204 ah->nexthdr = *skb_mac_header(skb);
205 *skb_mac_header(skb) = IPPROTO_AH;
208 top_iph->tot_len = htons(skb->len);
209 top_iph->frag_off = 0;
213 if (x->props.flags & XFRM_STATE_ALIGN4)
214 ah->hdrlen = (XFRM_ALIGN4(sizeof(*ah) + ahp->icv_trunc_len) >> 2) - 2;
216 ah->hdrlen = (XFRM_ALIGN8(sizeof(*ah) + ahp->icv_trunc_len) >> 2) - 2;
220 ah->seq_no = htonl(XFRM_SKB_CB(skb)->seq.output.low);
222 sg_init_table(sg, nfrags + sglists);
223 err = skb_to_sgvec_nomark(skb, sg, 0, skb->len);
224 if (unlikely(err < 0))
227 if (x->props.flags & XFRM_STATE_ESN) {
228 /* Attach seqhi sg right after packet payload */
229 *seqhi = htonl(XFRM_SKB_CB(skb)->seq.output.hi);
230 sg_set_buf(seqhisg, seqhi, seqhi_len);
232 ahash_request_set_crypt(req, sg, icv, skb->len + seqhi_len);
233 ahash_request_set_callback(req, 0, ah_output_done, skb);
235 AH_SKB_CB(skb)->tmp = iph;
237 err = crypto_ahash_digest(req);
239 if (err == -EINPROGRESS)
247 memcpy(ah->auth_data, icv, ahp->icv_trunc_len);
249 top_iph->tos = iph->tos;
250 top_iph->ttl = iph->ttl;
251 top_iph->frag_off = iph->frag_off;
252 if (top_iph->ihl != 5) {
253 top_iph->daddr = iph->daddr;
254 memcpy(top_iph+1, iph+1, top_iph->ihl*4 - sizeof(struct iphdr));
263 static void ah_input_done(struct crypto_async_request *base, int err)
267 struct iphdr *work_iph;
268 struct sk_buff *skb = base->data;
269 struct xfrm_state *x = xfrm_input_state(skb);
270 struct ah_data *ahp = x->data;
271 struct ip_auth_hdr *ah = ip_auth_hdr(skb);
272 int ihl = ip_hdrlen(skb);
273 int ah_hlen = (ah->hdrlen + 2) << 2;
278 work_iph = AH_SKB_CB(skb)->tmp;
279 auth_data = ah_tmp_auth(work_iph, ihl);
280 icv = ah_tmp_icv(ahp->ahash, auth_data, ahp->icv_trunc_len);
282 err = memcmp(icv, auth_data, ahp->icv_trunc_len) ? -EBADMSG: 0;
288 skb->network_header += ah_hlen;
289 memcpy(skb_network_header(skb), work_iph, ihl);
290 __skb_pull(skb, ah_hlen + ihl);
292 if (x->props.mode == XFRM_MODE_TUNNEL)
293 skb_reset_transport_header(skb);
295 skb_set_transport_header(skb, -ihl);
297 kfree(AH_SKB_CB(skb)->tmp);
298 xfrm_input_resume(skb, err);
301 static int ah_input(struct xfrm_state *x, struct sk_buff *skb)
309 struct sk_buff *trailer;
310 struct crypto_ahash *ahash;
311 struct ahash_request *req;
312 struct scatterlist *sg;
313 struct iphdr *iph, *work_iph;
314 struct ip_auth_hdr *ah;
320 struct scatterlist *seqhisg;
322 if (!pskb_may_pull(skb, sizeof(*ah)))
325 ah = (struct ip_auth_hdr *)skb->data;
329 nexthdr = ah->nexthdr;
330 ah_hlen = (ah->hdrlen + 2) << 2;
332 if (x->props.flags & XFRM_STATE_ALIGN4) {
333 if (ah_hlen != XFRM_ALIGN4(sizeof(*ah) + ahp->icv_full_len) &&
334 ah_hlen != XFRM_ALIGN4(sizeof(*ah) + ahp->icv_trunc_len))
337 if (ah_hlen != XFRM_ALIGN8(sizeof(*ah) + ahp->icv_full_len) &&
338 ah_hlen != XFRM_ALIGN8(sizeof(*ah) + ahp->icv_trunc_len))
342 if (!pskb_may_pull(skb, ah_hlen))
345 /* We are going to _remove_ AH header to keep sockets happy,
346 * so... Later this can change. */
347 if (skb_unclone(skb, GFP_ATOMIC))
350 skb->ip_summed = CHECKSUM_NONE;
353 if ((err = skb_cow_data(skb, 0, &trailer)) < 0)
357 ah = (struct ip_auth_hdr *)skb->data;
359 ihl = ip_hdrlen(skb);
361 if (x->props.flags & XFRM_STATE_ESN) {
363 seqhi_len = sizeof(*seqhi);
366 work_iph = ah_alloc_tmp(ahash, nfrags + sglists, ihl +
367 ahp->icv_trunc_len + seqhi_len);
373 seqhi = (__be32 *)((char *)work_iph + ihl);
374 auth_data = ah_tmp_auth(seqhi, seqhi_len);
375 icv = ah_tmp_icv(ahash, auth_data, ahp->icv_trunc_len);
376 req = ah_tmp_req(ahash, icv);
377 sg = ah_req_sg(ahash, req);
378 seqhisg = sg + nfrags;
380 memcpy(work_iph, iph, ihl);
381 memcpy(auth_data, ah->auth_data, ahp->icv_trunc_len);
382 memset(ah->auth_data, 0, ahp->icv_trunc_len);
388 if (ihl > sizeof(*iph)) {
390 err = ip_clear_mutable_options(iph, &dummy);
397 sg_init_table(sg, nfrags + sglists);
398 err = skb_to_sgvec_nomark(skb, sg, 0, skb->len);
399 if (unlikely(err < 0))
402 if (x->props.flags & XFRM_STATE_ESN) {
403 /* Attach seqhi sg right after packet payload */
404 *seqhi = XFRM_SKB_CB(skb)->seq.input.hi;
405 sg_set_buf(seqhisg, seqhi, seqhi_len);
407 ahash_request_set_crypt(req, sg, icv, skb->len + seqhi_len);
408 ahash_request_set_callback(req, 0, ah_input_done, skb);
410 AH_SKB_CB(skb)->tmp = work_iph;
412 err = crypto_ahash_digest(req);
414 if (err == -EINPROGRESS)
420 err = memcmp(icv, auth_data, ahp->icv_trunc_len) ? -EBADMSG: 0;
424 skb->network_header += ah_hlen;
425 memcpy(skb_network_header(skb), work_iph, ihl);
426 __skb_pull(skb, ah_hlen + ihl);
427 if (x->props.mode == XFRM_MODE_TUNNEL)
428 skb_reset_transport_header(skb);
430 skb_set_transport_header(skb, -ihl);
440 static int ah4_err(struct sk_buff *skb, u32 info)
442 struct net *net = dev_net(skb->dev);
443 const struct iphdr *iph = (const struct iphdr *)skb->data;
444 struct ip_auth_hdr *ah = (struct ip_auth_hdr *)(skb->data+(iph->ihl<<2));
445 struct xfrm_state *x;
447 switch (icmp_hdr(skb)->type) {
448 case ICMP_DEST_UNREACH:
449 if (icmp_hdr(skb)->code != ICMP_FRAG_NEEDED)
457 x = xfrm_state_lookup(net, skb->mark, (const xfrm_address_t *)&iph->daddr,
458 ah->spi, IPPROTO_AH, AF_INET);
462 if (icmp_hdr(skb)->type == ICMP_DEST_UNREACH)
463 ipv4_update_pmtu(skb, net, info, 0, 0, IPPROTO_AH, 0);
465 ipv4_redirect(skb, net, 0, 0, IPPROTO_AH, 0);
471 static int ah_init_state(struct xfrm_state *x)
473 struct ah_data *ahp = NULL;
474 struct xfrm_algo_desc *aalg_desc;
475 struct crypto_ahash *ahash;
483 ahp = kzalloc(sizeof(*ahp), GFP_KERNEL);
487 ahash = crypto_alloc_ahash(x->aalg->alg_name, 0, 0);
492 if (crypto_ahash_setkey(ahash, x->aalg->alg_key,
493 (x->aalg->alg_key_len + 7) / 8))
497 * Lookup the algorithm description maintained by xfrm_algo,
498 * verify crypto transform properties, and store information
499 * we need for AH processing. This lookup cannot fail here
500 * after a successful crypto_alloc_ahash().
502 aalg_desc = xfrm_aalg_get_byname(x->aalg->alg_name, 0);
505 if (aalg_desc->uinfo.auth.icv_fullbits/8 !=
506 crypto_ahash_digestsize(ahash)) {
507 pr_info("%s: %s digestsize %u != %hu\n",
508 __func__, x->aalg->alg_name,
509 crypto_ahash_digestsize(ahash),
510 aalg_desc->uinfo.auth.icv_fullbits / 8);
514 ahp->icv_full_len = aalg_desc->uinfo.auth.icv_fullbits/8;
515 ahp->icv_trunc_len = x->aalg->alg_trunc_len/8;
517 if (x->props.flags & XFRM_STATE_ALIGN4)
518 x->props.header_len = XFRM_ALIGN4(sizeof(struct ip_auth_hdr) +
521 x->props.header_len = XFRM_ALIGN8(sizeof(struct ip_auth_hdr) +
523 if (x->props.mode == XFRM_MODE_TUNNEL)
524 x->props.header_len += sizeof(struct iphdr);
531 crypto_free_ahash(ahp->ahash);
537 static void ah_destroy(struct xfrm_state *x)
539 struct ah_data *ahp = x->data;
544 crypto_free_ahash(ahp->ahash);
548 static int ah4_rcv_cb(struct sk_buff *skb, int err)
553 static const struct xfrm_type ah_type =
555 .description = "AH4",
556 .owner = THIS_MODULE,
558 .flags = XFRM_TYPE_REPLAY_PROT,
559 .init_state = ah_init_state,
560 .destructor = ah_destroy,
565 static struct xfrm4_protocol ah4_protocol = {
566 .handler = xfrm4_rcv,
567 .input_handler = xfrm_input,
568 .cb_handler = ah4_rcv_cb,
569 .err_handler = ah4_err,
573 static int __init ah4_init(void)
575 if (xfrm_register_type(&ah_type, AF_INET) < 0) {
576 pr_info("%s: can't add xfrm type\n", __func__);
579 if (xfrm4_protocol_register(&ah4_protocol, IPPROTO_AH) < 0) {
580 pr_info("%s: can't add protocol\n", __func__);
581 xfrm_unregister_type(&ah_type, AF_INET);
587 static void __exit ah4_fini(void)
589 if (xfrm4_protocol_deregister(&ah4_protocol, IPPROTO_AH) < 0)
590 pr_info("%s: can't remove protocol\n", __func__);
591 if (xfrm_unregister_type(&ah_type, AF_INET) < 0)
592 pr_info("%s: can't remove xfrm type\n", __func__);
595 module_init(ah4_init);
596 module_exit(ah4_fini);
597 MODULE_LICENSE("GPL");
598 MODULE_ALIAS_XFRM_TYPE(AF_INET, XFRM_PROTO_AH);