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>
11 #include <linux/spinlock.h>
13 #include <net/protocol.h>
16 static int esp_output(struct xfrm_state *x, struct sk_buff *skb)
19 struct iphdr *top_iph;
20 struct ip_esp_hdr *esph;
21 struct crypto_blkcipher *tfm;
22 struct blkcipher_desc desc;
24 struct sk_buff *trailer;
31 /* skb is pure payload to encrypt */
35 /* Round to block size */
39 alen = esp->auth.icv_trunc_len;
43 blksize = ALIGN(crypto_blkcipher_blocksize(tfm), 4);
44 clen = ALIGN(clen + 2, blksize);
46 clen = ALIGN(clen, esp->conf.padlen);
48 if ((nfrags = skb_cow_data(skb, clen-skb->len+alen, &trailer)) < 0)
52 tail = skb_tail_pointer(trailer);
55 for (i=0; i<clen-skb->len - 2; i++)
58 tail[clen - skb->len - 2] = (clen - skb->len) - 2;
59 pskb_put(skb, trailer, clen - skb->len);
61 skb_push(skb, -skb_network_offset(skb));
62 top_iph = ip_hdr(skb);
63 esph = (struct ip_esp_hdr *)(skb_network_header(skb) +
65 top_iph->tot_len = htons(skb->len + alen);
66 *(skb_tail_pointer(trailer) - 1) = top_iph->protocol;
68 spin_lock_bh(&x->lock);
70 /* this is non-NULL only with UDP Encapsulation */
72 struct xfrm_encap_tmpl *encap = x->encap;
76 uh = (struct udphdr *)esph;
77 uh->source = encap->encap_sport;
78 uh->dest = encap->encap_dport;
79 uh->len = htons(skb->len + alen - top_iph->ihl*4);
82 switch (encap->encap_type) {
84 case UDP_ENCAP_ESPINUDP:
85 esph = (struct ip_esp_hdr *)(uh + 1);
87 case UDP_ENCAP_ESPINUDP_NON_IKE:
88 udpdata32 = (__be32 *)(uh + 1);
89 udpdata32[0] = udpdata32[1] = 0;
90 esph = (struct ip_esp_hdr *)(udpdata32 + 2);
94 top_iph->protocol = IPPROTO_UDP;
96 top_iph->protocol = IPPROTO_ESP;
98 esph->spi = x->id.spi;
99 esph->seq_no = htonl(XFRM_SKB_CB(skb)->seq);
101 if (esp->conf.ivlen) {
102 if (unlikely(!esp->conf.ivinitted)) {
103 get_random_bytes(esp->conf.ivec, esp->conf.ivlen);
104 esp->conf.ivinitted = 1;
106 crypto_blkcipher_set_iv(tfm, esp->conf.ivec, esp->conf.ivlen);
110 struct scatterlist *sg = &esp->sgbuf[0];
112 if (unlikely(nfrags > ESP_NUM_FAST_SG)) {
113 sg = kmalloc(sizeof(struct scatterlist)*nfrags, GFP_ATOMIC);
117 skb_to_sgvec(skb, sg, esph->enc_data+esp->conf.ivlen-skb->data, clen);
118 err = crypto_blkcipher_encrypt(&desc, sg, sg, clen);
119 if (unlikely(sg != &esp->sgbuf[0]))
126 if (esp->conf.ivlen) {
127 memcpy(esph->enc_data, esp->conf.ivec, esp->conf.ivlen);
128 crypto_blkcipher_get_iv(tfm, esp->conf.ivec, esp->conf.ivlen);
131 if (esp->auth.icv_full_len) {
132 err = esp_mac_digest(esp, skb, (u8 *)esph - skb->data,
133 sizeof(*esph) + esp->conf.ivlen + clen);
134 memcpy(pskb_put(skb, trailer, alen), esp->auth.work_icv, alen);
138 spin_unlock_bh(&x->lock);
140 ip_send_check(top_iph);
147 * Note: detecting truncated vs. non-truncated authentication data is very
148 * expensive, so we only support truncated data, which is the recommended
151 static int esp_input(struct xfrm_state *x, struct sk_buff *skb)
154 struct ip_esp_hdr *esph;
155 struct esp_data *esp = x->data;
156 struct crypto_blkcipher *tfm = esp->conf.tfm;
157 struct blkcipher_desc desc = { .tfm = tfm };
158 struct sk_buff *trailer;
159 int blksize = ALIGN(crypto_blkcipher_blocksize(tfm), 4);
160 int alen = esp->auth.icv_trunc_len;
161 int elen = skb->len - sizeof(struct ip_esp_hdr) - esp->conf.ivlen - alen;
165 struct scatterlist *sg;
169 if (!pskb_may_pull(skb, sizeof(struct ip_esp_hdr)))
172 if (elen <= 0 || (elen & (blksize-1)))
175 /* If integrity check is required, do this. */
176 if (esp->auth.icv_full_len) {
179 err = esp_mac_digest(esp, skb, 0, skb->len - alen);
183 if (skb_copy_bits(skb, skb->len - alen, sum, alen))
186 if (unlikely(memcmp(esp->auth.work_icv, sum, alen))) {
187 x->stats.integrity_failed++;
192 if ((nfrags = skb_cow_data(skb, 0, &trailer)) < 0)
195 skb->ip_summed = CHECKSUM_NONE;
197 esph = (struct ip_esp_hdr*)skb->data;
199 /* Get ivec. This can be wrong, check against another impls. */
201 crypto_blkcipher_set_iv(tfm, esph->enc_data, esp->conf.ivlen);
205 if (unlikely(nfrags > ESP_NUM_FAST_SG)) {
206 sg = kmalloc(sizeof(struct scatterlist)*nfrags, GFP_ATOMIC);
210 skb_to_sgvec(skb, sg, sizeof(struct ip_esp_hdr) + esp->conf.ivlen, elen);
211 err = crypto_blkcipher_decrypt(&desc, sg, sg, elen);
212 if (unlikely(sg != &esp->sgbuf[0]))
217 if (skb_copy_bits(skb, skb->len-alen-2, nexthdr, 2))
221 if (padlen+2 >= elen)
224 /* ... check padding bits here. Silly. :-) */
230 struct xfrm_encap_tmpl *encap = x->encap;
231 struct udphdr *uh = (void *)(skb_network_header(skb) + ihl);
234 * 1) if the NAT-T peer's IP or port changed then
235 * advertize the change to the keying daemon.
236 * This is an inbound SA, so just compare
239 if (iph->saddr != x->props.saddr.a4 ||
240 uh->source != encap->encap_sport) {
241 xfrm_address_t ipaddr;
243 ipaddr.a4 = iph->saddr;
244 km_new_mapping(x, &ipaddr, uh->source);
246 /* XXX: perhaps add an extra
247 * policy check here, to see
248 * if we should allow or
249 * reject a packet from a
256 * 2) ignore UDP/TCP checksums in case
257 * of NAT-T in Transport Mode, or
258 * perform other post-processing fixes
259 * as per draft-ietf-ipsec-udp-encaps-06,
262 if (x->props.mode == XFRM_MODE_TRANSPORT)
263 skb->ip_summed = CHECKSUM_UNNECESSARY;
266 iph->protocol = nexthdr[1];
267 pskb_trim(skb, skb->len - alen - padlen - 2);
268 __skb_pull(skb, sizeof(*esph) + esp->conf.ivlen);
269 skb_set_transport_header(skb, -ihl);
277 static u32 esp4_get_mtu(struct xfrm_state *x, int mtu)
279 struct esp_data *esp = x->data;
280 u32 blksize = ALIGN(crypto_blkcipher_blocksize(esp->conf.tfm), 4);
281 u32 align = max_t(u32, blksize, esp->conf.padlen);
284 mtu -= x->props.header_len + esp->auth.icv_trunc_len;
285 rem = mtu & (align - 1);
288 switch (x->props.mode) {
289 case XFRM_MODE_TUNNEL:
292 case XFRM_MODE_TRANSPORT:
295 mtu += min_t(u32, blksize - 4, rem);
298 /* The worst case. */
299 mtu += min_t(u32, IPV4_BEET_PHMAXLEN, rem);
306 static void esp4_err(struct sk_buff *skb, u32 info)
308 struct iphdr *iph = (struct iphdr*)skb->data;
309 struct ip_esp_hdr *esph = (struct ip_esp_hdr*)(skb->data+(iph->ihl<<2));
310 struct xfrm_state *x;
312 if (icmp_hdr(skb)->type != ICMP_DEST_UNREACH ||
313 icmp_hdr(skb)->code != ICMP_FRAG_NEEDED)
316 x = xfrm_state_lookup((xfrm_address_t *)&iph->daddr, esph->spi, IPPROTO_ESP, AF_INET);
319 NETDEBUG(KERN_DEBUG "pmtu discovery on SA ESP/%08x/%08x\n",
320 ntohl(esph->spi), ntohl(iph->daddr));
324 static void esp_destroy(struct xfrm_state *x)
326 struct esp_data *esp = x->data;
331 crypto_free_blkcipher(esp->conf.tfm);
332 esp->conf.tfm = NULL;
333 kfree(esp->conf.ivec);
334 esp->conf.ivec = NULL;
335 crypto_free_hash(esp->auth.tfm);
336 esp->auth.tfm = NULL;
337 kfree(esp->auth.work_icv);
338 esp->auth.work_icv = NULL;
342 static int esp_init_state(struct xfrm_state *x)
344 struct esp_data *esp = NULL;
345 struct crypto_blkcipher *tfm;
351 esp = kzalloc(sizeof(*esp), GFP_KERNEL);
356 struct xfrm_algo_desc *aalg_desc;
357 struct crypto_hash *hash;
359 hash = crypto_alloc_hash(x->aalg->alg_name, 0,
364 esp->auth.tfm = hash;
365 if (crypto_hash_setkey(hash, x->aalg->alg_key,
366 (x->aalg->alg_key_len + 7) / 8))
369 aalg_desc = xfrm_aalg_get_byname(x->aalg->alg_name, 0);
372 if (aalg_desc->uinfo.auth.icv_fullbits/8 !=
373 crypto_hash_digestsize(hash)) {
374 NETDEBUG(KERN_INFO "ESP: %s digestsize %u != %hu\n",
376 crypto_hash_digestsize(hash),
377 aalg_desc->uinfo.auth.icv_fullbits/8);
381 esp->auth.icv_full_len = aalg_desc->uinfo.auth.icv_fullbits/8;
382 esp->auth.icv_trunc_len = aalg_desc->uinfo.auth.icv_truncbits/8;
384 esp->auth.work_icv = kmalloc(esp->auth.icv_full_len, GFP_KERNEL);
385 if (!esp->auth.work_icv)
389 tfm = crypto_alloc_blkcipher(x->ealg->alg_name, 0, CRYPTO_ALG_ASYNC);
393 esp->conf.ivlen = crypto_blkcipher_ivsize(tfm);
394 esp->conf.padlen = 0;
395 if (esp->conf.ivlen) {
396 esp->conf.ivec = kmalloc(esp->conf.ivlen, GFP_KERNEL);
397 if (unlikely(esp->conf.ivec == NULL))
399 esp->conf.ivinitted = 0;
401 if (crypto_blkcipher_setkey(tfm, x->ealg->alg_key,
402 (x->ealg->alg_key_len + 7) / 8))
404 x->props.header_len = sizeof(struct ip_esp_hdr) + esp->conf.ivlen;
405 if (x->props.mode == XFRM_MODE_TUNNEL)
406 x->props.header_len += sizeof(struct iphdr);
407 else if (x->props.mode == XFRM_MODE_BEET)
408 x->props.header_len += IPV4_BEET_PHMAXLEN;
410 struct xfrm_encap_tmpl *encap = x->encap;
412 switch (encap->encap_type) {
415 case UDP_ENCAP_ESPINUDP:
416 x->props.header_len += sizeof(struct udphdr);
418 case UDP_ENCAP_ESPINUDP_NON_IKE:
419 x->props.header_len += sizeof(struct udphdr) + 2 * sizeof(u32);
424 align = ALIGN(crypto_blkcipher_blocksize(esp->conf.tfm), 4);
425 if (esp->conf.padlen)
426 align = max_t(u32, align, esp->conf.padlen);
427 x->props.trailer_len = align + 1 + esp->auth.icv_trunc_len;
437 static struct xfrm_type esp_type =
439 .description = "ESP4",
440 .owner = THIS_MODULE,
441 .proto = IPPROTO_ESP,
442 .flags = XFRM_TYPE_REPLAY_PROT,
443 .init_state = esp_init_state,
444 .destructor = esp_destroy,
445 .get_mtu = esp4_get_mtu,
450 static struct net_protocol esp4_protocol = {
451 .handler = xfrm4_rcv,
452 .err_handler = esp4_err,
456 static int __init esp4_init(void)
458 if (xfrm_register_type(&esp_type, AF_INET) < 0) {
459 printk(KERN_INFO "ip esp init: can't add xfrm type\n");
462 if (inet_add_protocol(&esp4_protocol, IPPROTO_ESP) < 0) {
463 printk(KERN_INFO "ip esp init: can't add protocol\n");
464 xfrm_unregister_type(&esp_type, AF_INET);
470 static void __exit esp4_fini(void)
472 if (inet_del_protocol(&esp4_protocol, IPPROTO_ESP) < 0)
473 printk(KERN_INFO "ip esp close: can't remove protocol\n");
474 if (xfrm_unregister_type(&esp_type, AF_INET) < 0)
475 printk(KERN_INFO "ip esp close: can't remove xfrm type\n");
478 module_init(esp4_init);
479 module_exit(esp4_fini);
480 MODULE_LICENSE("GPL");
481 MODULE_ALIAS_XFRM_TYPE(AF_INET, XFRM_PROTO_ESP);