2 #include <linux/module.h>
6 #include <asm/scatterlist.h>
7 #include <linux/crypto.h>
8 #include <linux/kernel.h>
9 #include <linux/pfkeyv2.h>
10 #include <linux/random.h>
12 #include <net/protocol.h>
15 static int esp_output(struct xfrm_state *x, struct sk_buff *skb)
18 struct iphdr *top_iph;
19 struct ip_esp_hdr *esph;
20 struct crypto_blkcipher *tfm;
21 struct blkcipher_desc desc;
23 struct sk_buff *trailer;
30 /* Strip IP+ESP header. */
31 __skb_pull(skb, skb_transport_offset(skb));
32 /* Now skb is pure payload to encrypt */
36 /* Round to block size */
40 alen = esp->auth.icv_trunc_len;
44 blksize = ALIGN(crypto_blkcipher_blocksize(tfm), 4);
45 clen = ALIGN(clen + 2, blksize);
47 clen = ALIGN(clen, esp->conf.padlen);
49 if ((nfrags = skb_cow_data(skb, clen-skb->len+alen, &trailer)) < 0)
53 tail = skb_tail_pointer(trailer);
56 for (i=0; i<clen-skb->len - 2; i++)
59 tail[clen - skb->len - 2] = (clen - skb->len) - 2;
60 pskb_put(skb, trailer, clen - skb->len);
62 __skb_push(skb, -skb_network_offset(skb));
63 top_iph = ip_hdr(skb);
64 esph = (struct ip_esp_hdr *)(skb_network_header(skb) +
66 top_iph->tot_len = htons(skb->len + alen);
67 *(skb_tail_pointer(trailer) - 1) = top_iph->protocol;
69 /* this is non-NULL only with UDP Encapsulation */
71 struct xfrm_encap_tmpl *encap = x->encap;
75 uh = (struct udphdr *)esph;
76 uh->source = encap->encap_sport;
77 uh->dest = encap->encap_dport;
78 uh->len = htons(skb->len + alen - top_iph->ihl*4);
81 switch (encap->encap_type) {
83 case UDP_ENCAP_ESPINUDP:
84 esph = (struct ip_esp_hdr *)(uh + 1);
86 case UDP_ENCAP_ESPINUDP_NON_IKE:
87 udpdata32 = (__be32 *)(uh + 1);
88 udpdata32[0] = udpdata32[1] = 0;
89 esph = (struct ip_esp_hdr *)(udpdata32 + 2);
93 top_iph->protocol = IPPROTO_UDP;
95 top_iph->protocol = IPPROTO_ESP;
97 esph->spi = x->id.spi;
98 esph->seq_no = htonl(XFRM_SKB_CB(skb)->seq);
100 if (esp->conf.ivlen) {
101 if (unlikely(!esp->conf.ivinitted)) {
102 get_random_bytes(esp->conf.ivec, esp->conf.ivlen);
103 esp->conf.ivinitted = 1;
105 crypto_blkcipher_set_iv(tfm, esp->conf.ivec, esp->conf.ivlen);
109 struct scatterlist *sg = &esp->sgbuf[0];
111 if (unlikely(nfrags > ESP_NUM_FAST_SG)) {
112 sg = kmalloc(sizeof(struct scatterlist)*nfrags, GFP_ATOMIC);
116 skb_to_sgvec(skb, sg, esph->enc_data+esp->conf.ivlen-skb->data, clen);
117 err = crypto_blkcipher_encrypt(&desc, sg, sg, clen);
118 if (unlikely(sg != &esp->sgbuf[0]))
125 if (esp->conf.ivlen) {
126 memcpy(esph->enc_data, esp->conf.ivec, esp->conf.ivlen);
127 crypto_blkcipher_get_iv(tfm, esp->conf.ivec, esp->conf.ivlen);
130 if (esp->auth.icv_full_len) {
131 err = esp_mac_digest(esp, skb, (u8 *)esph - skb->data,
132 sizeof(*esph) + esp->conf.ivlen + clen);
133 memcpy(pskb_put(skb, trailer, alen), esp->auth.work_icv, alen);
136 ip_send_check(top_iph);
143 * Note: detecting truncated vs. non-truncated authentication data is very
144 * expensive, so we only support truncated data, which is the recommended
147 static int esp_input(struct xfrm_state *x, struct sk_buff *skb)
150 struct ip_esp_hdr *esph;
151 struct esp_data *esp = x->data;
152 struct crypto_blkcipher *tfm = esp->conf.tfm;
153 struct blkcipher_desc desc = { .tfm = tfm };
154 struct sk_buff *trailer;
155 int blksize = ALIGN(crypto_blkcipher_blocksize(tfm), 4);
156 int alen = esp->auth.icv_trunc_len;
157 int elen = skb->len - sizeof(struct ip_esp_hdr) - esp->conf.ivlen - alen;
161 struct scatterlist *sg;
165 if (!pskb_may_pull(skb, sizeof(struct ip_esp_hdr)))
168 if (elen <= 0 || (elen & (blksize-1)))
171 /* If integrity check is required, do this. */
172 if (esp->auth.icv_full_len) {
175 err = esp_mac_digest(esp, skb, 0, skb->len - alen);
179 if (skb_copy_bits(skb, skb->len - alen, sum, alen))
182 if (unlikely(memcmp(esp->auth.work_icv, sum, alen))) {
183 x->stats.integrity_failed++;
188 if ((nfrags = skb_cow_data(skb, 0, &trailer)) < 0)
191 skb->ip_summed = CHECKSUM_NONE;
193 esph = (struct ip_esp_hdr*)skb->data;
195 /* Get ivec. This can be wrong, check against another impls. */
197 crypto_blkcipher_set_iv(tfm, esph->enc_data, esp->conf.ivlen);
201 if (unlikely(nfrags > ESP_NUM_FAST_SG)) {
202 sg = kmalloc(sizeof(struct scatterlist)*nfrags, GFP_ATOMIC);
206 skb_to_sgvec(skb, sg, sizeof(struct ip_esp_hdr) + esp->conf.ivlen, elen);
207 err = crypto_blkcipher_decrypt(&desc, sg, sg, elen);
208 if (unlikely(sg != &esp->sgbuf[0]))
213 if (skb_copy_bits(skb, skb->len-alen-2, nexthdr, 2))
217 if (padlen+2 >= elen)
220 /* ... check padding bits here. Silly. :-) */
226 struct xfrm_encap_tmpl *encap = x->encap;
227 struct udphdr *uh = (void *)(skb_network_header(skb) + ihl);
230 * 1) if the NAT-T peer's IP or port changed then
231 * advertize the change to the keying daemon.
232 * This is an inbound SA, so just compare
235 if (iph->saddr != x->props.saddr.a4 ||
236 uh->source != encap->encap_sport) {
237 xfrm_address_t ipaddr;
239 ipaddr.a4 = iph->saddr;
240 km_new_mapping(x, &ipaddr, uh->source);
242 /* XXX: perhaps add an extra
243 * policy check here, to see
244 * if we should allow or
245 * reject a packet from a
252 * 2) ignore UDP/TCP checksums in case
253 * of NAT-T in Transport Mode, or
254 * perform other post-processing fixes
255 * as per draft-ietf-ipsec-udp-encaps-06,
258 if (x->props.mode == XFRM_MODE_TRANSPORT ||
259 x->props.mode == XFRM_MODE_BEET)
260 skb->ip_summed = CHECKSUM_UNNECESSARY;
263 iph->protocol = nexthdr[1];
264 pskb_trim(skb, skb->len - alen - padlen - 2);
265 __skb_pull(skb, sizeof(*esph) + esp->conf.ivlen);
266 skb_set_transport_header(skb, -ihl);
274 static u32 esp4_get_mtu(struct xfrm_state *x, int mtu)
276 struct esp_data *esp = x->data;
277 u32 blksize = ALIGN(crypto_blkcipher_blocksize(esp->conf.tfm), 4);
278 u32 align = max_t(u32, blksize, esp->conf.padlen);
281 mtu -= x->props.header_len + esp->auth.icv_trunc_len;
282 rem = mtu & (align - 1);
285 switch (x->props.mode) {
286 case XFRM_MODE_TUNNEL:
289 case XFRM_MODE_TRANSPORT:
292 mtu += min_t(u32, blksize - 4, rem);
295 /* The worst case. */
296 mtu += min_t(u32, IPV4_BEET_PHMAXLEN, rem);
303 static void esp4_err(struct sk_buff *skb, u32 info)
305 struct iphdr *iph = (struct iphdr*)skb->data;
306 struct ip_esp_hdr *esph = (struct ip_esp_hdr*)(skb->data+(iph->ihl<<2));
307 struct xfrm_state *x;
309 if (icmp_hdr(skb)->type != ICMP_DEST_UNREACH ||
310 icmp_hdr(skb)->code != ICMP_FRAG_NEEDED)
313 x = xfrm_state_lookup((xfrm_address_t *)&iph->daddr, esph->spi, IPPROTO_ESP, AF_INET);
316 NETDEBUG(KERN_DEBUG "pmtu discovery on SA ESP/%08x/%08x\n",
317 ntohl(esph->spi), ntohl(iph->daddr));
321 static void esp_destroy(struct xfrm_state *x)
323 struct esp_data *esp = x->data;
328 crypto_free_blkcipher(esp->conf.tfm);
329 esp->conf.tfm = NULL;
330 kfree(esp->conf.ivec);
331 esp->conf.ivec = NULL;
332 crypto_free_hash(esp->auth.tfm);
333 esp->auth.tfm = NULL;
334 kfree(esp->auth.work_icv);
335 esp->auth.work_icv = NULL;
339 static int esp_init_state(struct xfrm_state *x)
341 struct esp_data *esp = NULL;
342 struct crypto_blkcipher *tfm;
348 esp = kzalloc(sizeof(*esp), GFP_KERNEL);
353 struct xfrm_algo_desc *aalg_desc;
354 struct crypto_hash *hash;
356 hash = crypto_alloc_hash(x->aalg->alg_name, 0,
361 esp->auth.tfm = hash;
362 if (crypto_hash_setkey(hash, x->aalg->alg_key,
363 (x->aalg->alg_key_len + 7) / 8))
366 aalg_desc = xfrm_aalg_get_byname(x->aalg->alg_name, 0);
369 if (aalg_desc->uinfo.auth.icv_fullbits/8 !=
370 crypto_hash_digestsize(hash)) {
371 NETDEBUG(KERN_INFO "ESP: %s digestsize %u != %hu\n",
373 crypto_hash_digestsize(hash),
374 aalg_desc->uinfo.auth.icv_fullbits/8);
378 esp->auth.icv_full_len = aalg_desc->uinfo.auth.icv_fullbits/8;
379 esp->auth.icv_trunc_len = aalg_desc->uinfo.auth.icv_truncbits/8;
381 esp->auth.work_icv = kmalloc(esp->auth.icv_full_len, GFP_KERNEL);
382 if (!esp->auth.work_icv)
386 tfm = crypto_alloc_blkcipher(x->ealg->alg_name, 0, CRYPTO_ALG_ASYNC);
390 esp->conf.ivlen = crypto_blkcipher_ivsize(tfm);
391 esp->conf.padlen = 0;
392 if (esp->conf.ivlen) {
393 esp->conf.ivec = kmalloc(esp->conf.ivlen, GFP_KERNEL);
394 if (unlikely(esp->conf.ivec == NULL))
396 esp->conf.ivinitted = 0;
398 if (crypto_blkcipher_setkey(tfm, x->ealg->alg_key,
399 (x->ealg->alg_key_len + 7) / 8))
401 x->props.header_len = sizeof(struct ip_esp_hdr) + esp->conf.ivlen;
402 if (x->props.mode == XFRM_MODE_TUNNEL)
403 x->props.header_len += sizeof(struct iphdr);
404 else if (x->props.mode == XFRM_MODE_BEET)
405 x->props.header_len += IPV4_BEET_PHMAXLEN;
407 struct xfrm_encap_tmpl *encap = x->encap;
409 switch (encap->encap_type) {
412 case UDP_ENCAP_ESPINUDP:
413 x->props.header_len += sizeof(struct udphdr);
415 case UDP_ENCAP_ESPINUDP_NON_IKE:
416 x->props.header_len += sizeof(struct udphdr) + 2 * sizeof(u32);
421 align = ALIGN(crypto_blkcipher_blocksize(esp->conf.tfm), 4);
422 if (esp->conf.padlen)
423 align = max_t(u32, align, esp->conf.padlen);
424 x->props.trailer_len = align + 1 + esp->auth.icv_trunc_len;
434 static struct xfrm_type esp_type =
436 .description = "ESP4",
437 .owner = THIS_MODULE,
438 .proto = IPPROTO_ESP,
439 .flags = XFRM_TYPE_REPLAY_PROT,
440 .init_state = esp_init_state,
441 .destructor = esp_destroy,
442 .get_mtu = esp4_get_mtu,
447 static struct net_protocol esp4_protocol = {
448 .handler = xfrm4_rcv,
449 .err_handler = esp4_err,
453 static int __init esp4_init(void)
455 if (xfrm_register_type(&esp_type, AF_INET) < 0) {
456 printk(KERN_INFO "ip esp init: can't add xfrm type\n");
459 if (inet_add_protocol(&esp4_protocol, IPPROTO_ESP) < 0) {
460 printk(KERN_INFO "ip esp init: can't add protocol\n");
461 xfrm_unregister_type(&esp_type, AF_INET);
467 static void __exit esp4_fini(void)
469 if (inet_del_protocol(&esp4_protocol, IPPROTO_ESP) < 0)
470 printk(KERN_INFO "ip esp close: can't remove protocol\n");
471 if (xfrm_unregister_type(&esp_type, AF_INET) < 0)
472 printk(KERN_INFO "ip esp close: can't remove xfrm type\n");
475 module_init(esp4_init);
476 module_exit(esp4_fini);
477 MODULE_LICENSE("GPL");
478 MODULE_ALIAS_XFRM_TYPE(AF_INET, XFRM_PROTO_ESP);