Merge git://git.kernel.org/pub/scm/linux/kernel/git/herbert/crypto-2.6
[linux-2.6/btrfs-unstable.git] / net / ipv4 / esp4.c
blob360b565918c4b524d561a010ed7ec5df02312cdb
1 #define pr_fmt(fmt) "IPsec: " fmt
3 #include <crypto/aead.h>
4 #include <crypto/authenc.h>
5 #include <linux/err.h>
6 #include <linux/module.h>
7 #include <net/ip.h>
8 #include <net/xfrm.h>
9 #include <net/esp.h>
10 #include <linux/scatterlist.h>
11 #include <linux/kernel.h>
12 #include <linux/pfkeyv2.h>
13 #include <linux/rtnetlink.h>
14 #include <linux/slab.h>
15 #include <linux/spinlock.h>
16 #include <linux/in6.h>
17 #include <net/icmp.h>
18 #include <net/protocol.h>
19 #include <net/udp.h>
21 struct esp_skb_cb {
22 struct xfrm_skb_cb xfrm;
23 void *tmp;
26 #define ESP_SKB_CB(__skb) ((struct esp_skb_cb *)&((__skb)->cb[0]))
28 static u32 esp4_get_mtu(struct xfrm_state *x, int mtu);
31 * Allocate an AEAD request structure with extra space for SG and IV.
33 * For alignment considerations the IV is placed at the front, followed
34 * by the request and finally the SG list.
36 * TODO: Use spare space in skb for this where possible.
38 static void *esp_alloc_tmp(struct crypto_aead *aead, int nfrags, int seqhilen)
40 unsigned int len;
42 len = seqhilen;
44 len += crypto_aead_ivsize(aead);
46 if (len) {
47 len += crypto_aead_alignmask(aead) &
48 ~(crypto_tfm_ctx_alignment() - 1);
49 len = ALIGN(len, crypto_tfm_ctx_alignment());
52 len += sizeof(struct aead_givcrypt_request) + crypto_aead_reqsize(aead);
53 len = ALIGN(len, __alignof__(struct scatterlist));
55 len += sizeof(struct scatterlist) * nfrags;
57 return kmalloc(len, GFP_ATOMIC);
60 static inline __be32 *esp_tmp_seqhi(void *tmp)
62 return PTR_ALIGN((__be32 *)tmp, __alignof__(__be32));
64 static inline u8 *esp_tmp_iv(struct crypto_aead *aead, void *tmp, int seqhilen)
66 return crypto_aead_ivsize(aead) ?
67 PTR_ALIGN((u8 *)tmp + seqhilen,
68 crypto_aead_alignmask(aead) + 1) : tmp + seqhilen;
71 static inline struct aead_givcrypt_request *esp_tmp_givreq(
72 struct crypto_aead *aead, u8 *iv)
74 struct aead_givcrypt_request *req;
76 req = (void *)PTR_ALIGN(iv + crypto_aead_ivsize(aead),
77 crypto_tfm_ctx_alignment());
78 aead_givcrypt_set_tfm(req, aead);
79 return req;
82 static inline struct aead_request *esp_tmp_req(struct crypto_aead *aead, u8 *iv)
84 struct aead_request *req;
86 req = (void *)PTR_ALIGN(iv + crypto_aead_ivsize(aead),
87 crypto_tfm_ctx_alignment());
88 aead_request_set_tfm(req, aead);
89 return req;
92 static inline struct scatterlist *esp_req_sg(struct crypto_aead *aead,
93 struct aead_request *req)
95 return (void *)ALIGN((unsigned long)(req + 1) +
96 crypto_aead_reqsize(aead),
97 __alignof__(struct scatterlist));
100 static inline struct scatterlist *esp_givreq_sg(
101 struct crypto_aead *aead, struct aead_givcrypt_request *req)
103 return (void *)ALIGN((unsigned long)(req + 1) +
104 crypto_aead_reqsize(aead),
105 __alignof__(struct scatterlist));
108 static void esp_output_done(struct crypto_async_request *base, int err)
110 struct sk_buff *skb = base->data;
112 kfree(ESP_SKB_CB(skb)->tmp);
113 xfrm_output_resume(skb, err);
116 static int esp_output(struct xfrm_state *x, struct sk_buff *skb)
118 int err;
119 struct ip_esp_hdr *esph;
120 struct crypto_aead *aead;
121 struct aead_givcrypt_request *req;
122 struct scatterlist *sg;
123 struct scatterlist *asg;
124 struct sk_buff *trailer;
125 void *tmp;
126 u8 *iv;
127 u8 *tail;
128 int blksize;
129 int clen;
130 int alen;
131 int plen;
132 int tfclen;
133 int nfrags;
134 int assoclen;
135 int sglists;
136 int seqhilen;
137 __be32 *seqhi;
139 /* skb is pure payload to encrypt */
141 aead = x->data;
142 alen = crypto_aead_authsize(aead);
144 tfclen = 0;
145 if (x->tfcpad) {
146 struct xfrm_dst *dst = (struct xfrm_dst *)skb_dst(skb);
147 u32 padto;
149 padto = min(x->tfcpad, esp4_get_mtu(x, dst->child_mtu_cached));
150 if (skb->len < padto)
151 tfclen = padto - skb->len;
153 blksize = ALIGN(crypto_aead_blocksize(aead), 4);
154 clen = ALIGN(skb->len + 2 + tfclen, blksize);
155 plen = clen - skb->len - tfclen;
157 err = skb_cow_data(skb, tfclen + plen + alen, &trailer);
158 if (err < 0)
159 goto error;
160 nfrags = err;
162 assoclen = sizeof(*esph);
163 sglists = 1;
164 seqhilen = 0;
166 if (x->props.flags & XFRM_STATE_ESN) {
167 sglists += 2;
168 seqhilen += sizeof(__be32);
169 assoclen += seqhilen;
172 tmp = esp_alloc_tmp(aead, nfrags + sglists, seqhilen);
173 if (!tmp) {
174 err = -ENOMEM;
175 goto error;
178 seqhi = esp_tmp_seqhi(tmp);
179 iv = esp_tmp_iv(aead, tmp, seqhilen);
180 req = esp_tmp_givreq(aead, iv);
181 asg = esp_givreq_sg(aead, req);
182 sg = asg + sglists;
184 /* Fill padding... */
185 tail = skb_tail_pointer(trailer);
186 if (tfclen) {
187 memset(tail, 0, tfclen);
188 tail += tfclen;
190 do {
191 int i;
192 for (i = 0; i < plen - 2; i++)
193 tail[i] = i + 1;
194 } while (0);
195 tail[plen - 2] = plen - 2;
196 tail[plen - 1] = *skb_mac_header(skb);
197 pskb_put(skb, trailer, clen - skb->len + alen);
199 skb_push(skb, -skb_network_offset(skb));
200 esph = ip_esp_hdr(skb);
201 *skb_mac_header(skb) = IPPROTO_ESP;
203 /* this is non-NULL only with UDP Encapsulation */
204 if (x->encap) {
205 struct xfrm_encap_tmpl *encap = x->encap;
206 struct udphdr *uh;
207 __be32 *udpdata32;
208 __be16 sport, dport;
209 int encap_type;
211 spin_lock_bh(&x->lock);
212 sport = encap->encap_sport;
213 dport = encap->encap_dport;
214 encap_type = encap->encap_type;
215 spin_unlock_bh(&x->lock);
217 uh = (struct udphdr *)esph;
218 uh->source = sport;
219 uh->dest = dport;
220 uh->len = htons(skb->len - skb_transport_offset(skb));
221 uh->check = 0;
223 switch (encap_type) {
224 default:
225 case UDP_ENCAP_ESPINUDP:
226 esph = (struct ip_esp_hdr *)(uh + 1);
227 break;
228 case UDP_ENCAP_ESPINUDP_NON_IKE:
229 udpdata32 = (__be32 *)(uh + 1);
230 udpdata32[0] = udpdata32[1] = 0;
231 esph = (struct ip_esp_hdr *)(udpdata32 + 2);
232 break;
235 *skb_mac_header(skb) = IPPROTO_UDP;
238 esph->spi = x->id.spi;
239 esph->seq_no = htonl(XFRM_SKB_CB(skb)->seq.output.low);
241 sg_init_table(sg, nfrags);
242 skb_to_sgvec(skb, sg,
243 esph->enc_data + crypto_aead_ivsize(aead) - skb->data,
244 clen + alen);
246 if ((x->props.flags & XFRM_STATE_ESN)) {
247 sg_init_table(asg, 3);
248 sg_set_buf(asg, &esph->spi, sizeof(__be32));
249 *seqhi = htonl(XFRM_SKB_CB(skb)->seq.output.hi);
250 sg_set_buf(asg + 1, seqhi, seqhilen);
251 sg_set_buf(asg + 2, &esph->seq_no, sizeof(__be32));
252 } else
253 sg_init_one(asg, esph, sizeof(*esph));
255 aead_givcrypt_set_callback(req, 0, esp_output_done, skb);
256 aead_givcrypt_set_crypt(req, sg, sg, clen, iv);
257 aead_givcrypt_set_assoc(req, asg, assoclen);
258 aead_givcrypt_set_giv(req, esph->enc_data,
259 XFRM_SKB_CB(skb)->seq.output.low);
261 ESP_SKB_CB(skb)->tmp = tmp;
262 err = crypto_aead_givencrypt(req);
263 if (err == -EINPROGRESS)
264 goto error;
266 if (err == -EBUSY)
267 err = NET_XMIT_DROP;
269 kfree(tmp);
271 error:
272 return err;
275 static int esp_input_done2(struct sk_buff *skb, int err)
277 const struct iphdr *iph;
278 struct xfrm_state *x = xfrm_input_state(skb);
279 struct crypto_aead *aead = x->data;
280 int alen = crypto_aead_authsize(aead);
281 int hlen = sizeof(struct ip_esp_hdr) + crypto_aead_ivsize(aead);
282 int elen = skb->len - hlen;
283 int ihl;
284 u8 nexthdr[2];
285 int padlen;
287 kfree(ESP_SKB_CB(skb)->tmp);
289 if (unlikely(err))
290 goto out;
292 if (skb_copy_bits(skb, skb->len-alen-2, nexthdr, 2))
293 BUG();
295 err = -EINVAL;
296 padlen = nexthdr[0];
297 if (padlen + 2 + alen >= elen)
298 goto out;
300 /* ... check padding bits here. Silly. :-) */
302 iph = ip_hdr(skb);
303 ihl = iph->ihl * 4;
305 if (x->encap) {
306 struct xfrm_encap_tmpl *encap = x->encap;
307 struct udphdr *uh = (void *)(skb_network_header(skb) + ihl);
310 * 1) if the NAT-T peer's IP or port changed then
311 * advertize the change to the keying daemon.
312 * This is an inbound SA, so just compare
313 * SRC ports.
315 if (iph->saddr != x->props.saddr.a4 ||
316 uh->source != encap->encap_sport) {
317 xfrm_address_t ipaddr;
319 ipaddr.a4 = iph->saddr;
320 km_new_mapping(x, &ipaddr, uh->source);
322 /* XXX: perhaps add an extra
323 * policy check here, to see
324 * if we should allow or
325 * reject a packet from a
326 * different source
327 * address/port.
332 * 2) ignore UDP/TCP checksums in case
333 * of NAT-T in Transport Mode, or
334 * perform other post-processing fixes
335 * as per draft-ietf-ipsec-udp-encaps-06,
336 * section 3.1.2
338 if (x->props.mode == XFRM_MODE_TRANSPORT)
339 skb->ip_summed = CHECKSUM_UNNECESSARY;
342 pskb_trim(skb, skb->len - alen - padlen - 2);
343 __skb_pull(skb, hlen);
344 if (x->props.mode == XFRM_MODE_TUNNEL)
345 skb_reset_transport_header(skb);
346 else
347 skb_set_transport_header(skb, -ihl);
349 err = nexthdr[1];
351 /* RFC4303: Drop dummy packets without any error */
352 if (err == IPPROTO_NONE)
353 err = -EINVAL;
355 out:
356 return err;
359 static void esp_input_done(struct crypto_async_request *base, int err)
361 struct sk_buff *skb = base->data;
363 xfrm_input_resume(skb, esp_input_done2(skb, err));
367 * Note: detecting truncated vs. non-truncated authentication data is very
368 * expensive, so we only support truncated data, which is the recommended
369 * and common case.
371 static int esp_input(struct xfrm_state *x, struct sk_buff *skb)
373 struct ip_esp_hdr *esph;
374 struct crypto_aead *aead = x->data;
375 struct aead_request *req;
376 struct sk_buff *trailer;
377 int elen = skb->len - sizeof(*esph) - crypto_aead_ivsize(aead);
378 int nfrags;
379 int assoclen;
380 int sglists;
381 int seqhilen;
382 __be32 *seqhi;
383 void *tmp;
384 u8 *iv;
385 struct scatterlist *sg;
386 struct scatterlist *asg;
387 int err = -EINVAL;
389 if (!pskb_may_pull(skb, sizeof(*esph) + crypto_aead_ivsize(aead)))
390 goto out;
392 if (elen <= 0)
393 goto out;
395 if ((err = skb_cow_data(skb, 0, &trailer)) < 0)
396 goto out;
397 nfrags = err;
399 assoclen = sizeof(*esph);
400 sglists = 1;
401 seqhilen = 0;
403 if (x->props.flags & XFRM_STATE_ESN) {
404 sglists += 2;
405 seqhilen += sizeof(__be32);
406 assoclen += seqhilen;
409 err = -ENOMEM;
410 tmp = esp_alloc_tmp(aead, nfrags + sglists, seqhilen);
411 if (!tmp)
412 goto out;
414 ESP_SKB_CB(skb)->tmp = tmp;
415 seqhi = esp_tmp_seqhi(tmp);
416 iv = esp_tmp_iv(aead, tmp, seqhilen);
417 req = esp_tmp_req(aead, iv);
418 asg = esp_req_sg(aead, req);
419 sg = asg + sglists;
421 skb->ip_summed = CHECKSUM_NONE;
423 esph = (struct ip_esp_hdr *)skb->data;
425 /* Get ivec. This can be wrong, check against another impls. */
426 iv = esph->enc_data;
428 sg_init_table(sg, nfrags);
429 skb_to_sgvec(skb, sg, sizeof(*esph) + crypto_aead_ivsize(aead), elen);
431 if ((x->props.flags & XFRM_STATE_ESN)) {
432 sg_init_table(asg, 3);
433 sg_set_buf(asg, &esph->spi, sizeof(__be32));
434 *seqhi = XFRM_SKB_CB(skb)->seq.input.hi;
435 sg_set_buf(asg + 1, seqhi, seqhilen);
436 sg_set_buf(asg + 2, &esph->seq_no, sizeof(__be32));
437 } else
438 sg_init_one(asg, esph, sizeof(*esph));
440 aead_request_set_callback(req, 0, esp_input_done, skb);
441 aead_request_set_crypt(req, sg, sg, elen, iv);
442 aead_request_set_assoc(req, asg, assoclen);
444 err = crypto_aead_decrypt(req);
445 if (err == -EINPROGRESS)
446 goto out;
448 err = esp_input_done2(skb, err);
450 out:
451 return err;
454 static u32 esp4_get_mtu(struct xfrm_state *x, int mtu)
456 struct crypto_aead *aead = x->data;
457 u32 blksize = ALIGN(crypto_aead_blocksize(aead), 4);
458 unsigned int net_adj;
460 switch (x->props.mode) {
461 case XFRM_MODE_TRANSPORT:
462 case XFRM_MODE_BEET:
463 net_adj = sizeof(struct iphdr);
464 break;
465 case XFRM_MODE_TUNNEL:
466 net_adj = 0;
467 break;
468 default:
469 BUG();
472 return ((mtu - x->props.header_len - crypto_aead_authsize(aead) -
473 net_adj) & ~(blksize - 1)) + net_adj - 2;
476 static int esp4_err(struct sk_buff *skb, u32 info)
478 struct net *net = dev_net(skb->dev);
479 const struct iphdr *iph = (const struct iphdr *)skb->data;
480 struct ip_esp_hdr *esph = (struct ip_esp_hdr *)(skb->data+(iph->ihl<<2));
481 struct xfrm_state *x;
483 switch (icmp_hdr(skb)->type) {
484 case ICMP_DEST_UNREACH:
485 if (icmp_hdr(skb)->code != ICMP_FRAG_NEEDED)
486 return 0;
487 case ICMP_REDIRECT:
488 break;
489 default:
490 return 0;
493 x = xfrm_state_lookup(net, skb->mark, (const xfrm_address_t *)&iph->daddr,
494 esph->spi, IPPROTO_ESP, AF_INET);
495 if (!x)
496 return 0;
498 if (icmp_hdr(skb)->type == ICMP_DEST_UNREACH)
499 ipv4_update_pmtu(skb, net, info, 0, 0, IPPROTO_ESP, 0);
500 else
501 ipv4_redirect(skb, net, 0, 0, IPPROTO_ESP, 0);
502 xfrm_state_put(x);
504 return 0;
507 static void esp_destroy(struct xfrm_state *x)
509 struct crypto_aead *aead = x->data;
511 if (!aead)
512 return;
514 crypto_free_aead(aead);
517 static int esp_init_aead(struct xfrm_state *x)
519 struct crypto_aead *aead;
520 int err;
522 aead = crypto_alloc_aead(x->aead->alg_name, 0, 0);
523 err = PTR_ERR(aead);
524 if (IS_ERR(aead))
525 goto error;
527 x->data = aead;
529 err = crypto_aead_setkey(aead, x->aead->alg_key,
530 (x->aead->alg_key_len + 7) / 8);
531 if (err)
532 goto error;
534 err = crypto_aead_setauthsize(aead, x->aead->alg_icv_len / 8);
535 if (err)
536 goto error;
538 error:
539 return err;
542 static int esp_init_authenc(struct xfrm_state *x)
544 struct crypto_aead *aead;
545 struct crypto_authenc_key_param *param;
546 struct rtattr *rta;
547 char *key;
548 char *p;
549 char authenc_name[CRYPTO_MAX_ALG_NAME];
550 unsigned int keylen;
551 int err;
553 err = -EINVAL;
554 if (x->ealg == NULL)
555 goto error;
557 err = -ENAMETOOLONG;
559 if ((x->props.flags & XFRM_STATE_ESN)) {
560 if (snprintf(authenc_name, CRYPTO_MAX_ALG_NAME,
561 "authencesn(%s,%s)",
562 x->aalg ? x->aalg->alg_name : "digest_null",
563 x->ealg->alg_name) >= CRYPTO_MAX_ALG_NAME)
564 goto error;
565 } else {
566 if (snprintf(authenc_name, CRYPTO_MAX_ALG_NAME,
567 "authenc(%s,%s)",
568 x->aalg ? x->aalg->alg_name : "digest_null",
569 x->ealg->alg_name) >= CRYPTO_MAX_ALG_NAME)
570 goto error;
573 aead = crypto_alloc_aead(authenc_name, 0, 0);
574 err = PTR_ERR(aead);
575 if (IS_ERR(aead))
576 goto error;
578 x->data = aead;
580 keylen = (x->aalg ? (x->aalg->alg_key_len + 7) / 8 : 0) +
581 (x->ealg->alg_key_len + 7) / 8 + RTA_SPACE(sizeof(*param));
582 err = -ENOMEM;
583 key = kmalloc(keylen, GFP_KERNEL);
584 if (!key)
585 goto error;
587 p = key;
588 rta = (void *)p;
589 rta->rta_type = CRYPTO_AUTHENC_KEYA_PARAM;
590 rta->rta_len = RTA_LENGTH(sizeof(*param));
591 param = RTA_DATA(rta);
592 p += RTA_SPACE(sizeof(*param));
594 if (x->aalg) {
595 struct xfrm_algo_desc *aalg_desc;
597 memcpy(p, x->aalg->alg_key, (x->aalg->alg_key_len + 7) / 8);
598 p += (x->aalg->alg_key_len + 7) / 8;
600 aalg_desc = xfrm_aalg_get_byname(x->aalg->alg_name, 0);
601 BUG_ON(!aalg_desc);
603 err = -EINVAL;
604 if (aalg_desc->uinfo.auth.icv_fullbits/8 !=
605 crypto_aead_authsize(aead)) {
606 NETDEBUG(KERN_INFO "ESP: %s digestsize %u != %hu\n",
607 x->aalg->alg_name,
608 crypto_aead_authsize(aead),
609 aalg_desc->uinfo.auth.icv_fullbits/8);
610 goto free_key;
613 err = crypto_aead_setauthsize(
614 aead, x->aalg->alg_trunc_len / 8);
615 if (err)
616 goto free_key;
619 param->enckeylen = cpu_to_be32((x->ealg->alg_key_len + 7) / 8);
620 memcpy(p, x->ealg->alg_key, (x->ealg->alg_key_len + 7) / 8);
622 err = crypto_aead_setkey(aead, key, keylen);
624 free_key:
625 kfree(key);
627 error:
628 return err;
631 static int esp_init_state(struct xfrm_state *x)
633 struct crypto_aead *aead;
634 u32 align;
635 int err;
637 x->data = NULL;
639 if (x->aead)
640 err = esp_init_aead(x);
641 else
642 err = esp_init_authenc(x);
644 if (err)
645 goto error;
647 aead = x->data;
649 x->props.header_len = sizeof(struct ip_esp_hdr) +
650 crypto_aead_ivsize(aead);
651 if (x->props.mode == XFRM_MODE_TUNNEL)
652 x->props.header_len += sizeof(struct iphdr);
653 else if (x->props.mode == XFRM_MODE_BEET && x->sel.family != AF_INET6)
654 x->props.header_len += IPV4_BEET_PHMAXLEN;
655 if (x->encap) {
656 struct xfrm_encap_tmpl *encap = x->encap;
658 switch (encap->encap_type) {
659 default:
660 goto error;
661 case UDP_ENCAP_ESPINUDP:
662 x->props.header_len += sizeof(struct udphdr);
663 break;
664 case UDP_ENCAP_ESPINUDP_NON_IKE:
665 x->props.header_len += sizeof(struct udphdr) + 2 * sizeof(u32);
666 break;
670 align = ALIGN(crypto_aead_blocksize(aead), 4);
671 x->props.trailer_len = align + 1 + crypto_aead_authsize(aead);
673 error:
674 return err;
677 static int esp4_rcv_cb(struct sk_buff *skb, int err)
679 return 0;
682 static const struct xfrm_type esp_type =
684 .description = "ESP4",
685 .owner = THIS_MODULE,
686 .proto = IPPROTO_ESP,
687 .flags = XFRM_TYPE_REPLAY_PROT,
688 .init_state = esp_init_state,
689 .destructor = esp_destroy,
690 .get_mtu = esp4_get_mtu,
691 .input = esp_input,
692 .output = esp_output
695 static struct xfrm4_protocol esp4_protocol = {
696 .handler = xfrm4_rcv,
697 .input_handler = xfrm_input,
698 .cb_handler = esp4_rcv_cb,
699 .err_handler = esp4_err,
700 .priority = 0,
703 static int __init esp4_init(void)
705 if (xfrm_register_type(&esp_type, AF_INET) < 0) {
706 pr_info("%s: can't add xfrm type\n", __func__);
707 return -EAGAIN;
709 if (xfrm4_protocol_register(&esp4_protocol, IPPROTO_ESP) < 0) {
710 pr_info("%s: can't add protocol\n", __func__);
711 xfrm_unregister_type(&esp_type, AF_INET);
712 return -EAGAIN;
714 return 0;
717 static void __exit esp4_fini(void)
719 if (xfrm4_protocol_deregister(&esp4_protocol, IPPROTO_ESP) < 0)
720 pr_info("%s: can't remove protocol\n", __func__);
721 if (xfrm_unregister_type(&esp_type, AF_INET) < 0)
722 pr_info("%s: can't remove xfrm type\n", __func__);
725 module_init(esp4_init);
726 module_exit(esp4_fini);
727 MODULE_LICENSE("GPL");
728 MODULE_ALIAS_XFRM_TYPE(AF_INET, XFRM_PROTO_ESP);