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;
29 /* Strip IP+ESP header. */
30 __skb_pull(skb, skb->h.raw - skb->data);
31 /* Now 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)
54 for (i=0; i<clen-skb->len - 2; i++)
55 *(u8*)(trailer->tail + i) = i+1;
57 *(u8*)(trailer->tail + clen-skb->len - 2) = (clen - skb->len)-2;
58 pskb_put(skb, trailer, clen - skb->len);
60 __skb_push(skb, skb->data - skb->nh.raw);
61 top_iph = skb->nh.iph;
62 esph = (struct ip_esp_hdr *)(skb->nh.raw + top_iph->ihl*4);
63 top_iph->tot_len = htons(skb->len + alen);
64 *(u8*)(trailer->tail - 1) = top_iph->protocol;
66 /* this is non-NULL only with UDP Encapsulation */
68 struct xfrm_encap_tmpl *encap = x->encap;
72 uh = (struct udphdr *)esph;
73 uh->source = encap->encap_sport;
74 uh->dest = encap->encap_dport;
75 uh->len = htons(skb->len + alen - top_iph->ihl*4);
78 switch (encap->encap_type) {
80 case UDP_ENCAP_ESPINUDP:
81 esph = (struct ip_esp_hdr *)(uh + 1);
83 case UDP_ENCAP_ESPINUDP_NON_IKE:
84 udpdata32 = (u32 *)(uh + 1);
85 udpdata32[0] = udpdata32[1] = 0;
86 esph = (struct ip_esp_hdr *)(udpdata32 + 2);
90 top_iph->protocol = IPPROTO_UDP;
92 top_iph->protocol = IPPROTO_ESP;
94 esph->spi = x->id.spi;
95 esph->seq_no = htonl(++x->replay.oseq);
96 xfrm_aevent_doreplay(x);
99 crypto_blkcipher_set_iv(tfm, esp->conf.ivec, esp->conf.ivlen);
102 struct scatterlist *sg = &esp->sgbuf[0];
104 if (unlikely(nfrags > ESP_NUM_FAST_SG)) {
105 sg = kmalloc(sizeof(struct scatterlist)*nfrags, GFP_ATOMIC);
109 skb_to_sgvec(skb, sg, esph->enc_data+esp->conf.ivlen-skb->data, clen);
110 err = crypto_blkcipher_encrypt(&desc, sg, sg, clen);
111 if (unlikely(sg != &esp->sgbuf[0]))
118 if (esp->conf.ivlen) {
119 memcpy(esph->enc_data, esp->conf.ivec, esp->conf.ivlen);
120 crypto_blkcipher_get_iv(tfm, esp->conf.ivec, esp->conf.ivlen);
123 if (esp->auth.icv_full_len) {
124 esp->auth.icv(esp, skb, (u8*)esph-skb->data,
125 sizeof(struct ip_esp_hdr) + esp->conf.ivlen+clen, trailer->tail);
126 pskb_put(skb, trailer, alen);
129 ip_send_check(top_iph);
136 * Note: detecting truncated vs. non-truncated authentication data is very
137 * expensive, so we only support truncated data, which is the recommended
140 static int esp_input(struct xfrm_state *x, struct sk_buff *skb)
143 struct ip_esp_hdr *esph;
144 struct esp_data *esp = x->data;
145 struct crypto_blkcipher *tfm = esp->conf.tfm;
146 struct blkcipher_desc desc = { .tfm = tfm };
147 struct sk_buff *trailer;
148 int blksize = ALIGN(crypto_blkcipher_blocksize(tfm), 4);
149 int alen = esp->auth.icv_trunc_len;
150 int elen = skb->len - sizeof(struct ip_esp_hdr) - esp->conf.ivlen - alen;
154 struct scatterlist *sg;
158 if (!pskb_may_pull(skb, sizeof(struct ip_esp_hdr)))
161 if (elen <= 0 || (elen & (blksize-1)))
164 /* If integrity check is required, do this. */
165 if (esp->auth.icv_full_len) {
166 u8 sum[esp->auth.icv_full_len];
169 esp->auth.icv(esp, skb, 0, skb->len-alen, sum);
171 if (skb_copy_bits(skb, skb->len-alen, sum1, alen))
174 if (unlikely(memcmp(sum, sum1, alen))) {
175 x->stats.integrity_failed++;
180 if ((nfrags = skb_cow_data(skb, 0, &trailer)) < 0)
183 skb->ip_summed = CHECKSUM_NONE;
185 esph = (struct ip_esp_hdr*)skb->data;
187 /* Get ivec. This can be wrong, check against another impls. */
189 crypto_blkcipher_set_iv(tfm, esph->enc_data, esp->conf.ivlen);
193 if (unlikely(nfrags > ESP_NUM_FAST_SG)) {
194 sg = kmalloc(sizeof(struct scatterlist)*nfrags, GFP_ATOMIC);
198 skb_to_sgvec(skb, sg, sizeof(struct ip_esp_hdr) + esp->conf.ivlen, elen);
199 err = crypto_blkcipher_decrypt(&desc, sg, sg, elen);
200 if (unlikely(sg != &esp->sgbuf[0]))
205 if (skb_copy_bits(skb, skb->len-alen-2, nexthdr, 2))
209 if (padlen+2 >= elen)
212 /* ... check padding bits here. Silly. :-) */
218 struct xfrm_encap_tmpl *encap = x->encap;
219 struct udphdr *uh = (void *)(skb->nh.raw + ihl);
222 * 1) if the NAT-T peer's IP or port changed then
223 * advertize the change to the keying daemon.
224 * This is an inbound SA, so just compare
227 if (iph->saddr != x->props.saddr.a4 ||
228 uh->source != encap->encap_sport) {
229 xfrm_address_t ipaddr;
231 ipaddr.a4 = iph->saddr;
232 km_new_mapping(x, &ipaddr, uh->source);
234 /* XXX: perhaps add an extra
235 * policy check here, to see
236 * if we should allow or
237 * reject a packet from a
244 * 2) ignore UDP/TCP checksums in case
245 * of NAT-T in Transport Mode, or
246 * perform other post-processing fixes
247 * as per draft-ietf-ipsec-udp-encaps-06,
251 skb->ip_summed = CHECKSUM_UNNECESSARY;
254 iph->protocol = nexthdr[1];
255 pskb_trim(skb, skb->len - alen - padlen - 2);
256 skb->h.raw = __skb_pull(skb, sizeof(*esph) + esp->conf.ivlen) - ihl;
264 static u32 esp4_get_max_size(struct xfrm_state *x, int mtu)
266 struct esp_data *esp = x->data;
267 u32 blksize = ALIGN(crypto_blkcipher_blocksize(esp->conf.tfm), 4);
270 mtu = ALIGN(mtu + 2, blksize);
272 /* The worst case. */
273 mtu = ALIGN(mtu + 2, 4) + blksize - 4;
275 if (esp->conf.padlen)
276 mtu = ALIGN(mtu, esp->conf.padlen);
278 return mtu + x->props.header_len + esp->auth.icv_trunc_len;
281 static void esp4_err(struct sk_buff *skb, u32 info)
283 struct iphdr *iph = (struct iphdr*)skb->data;
284 struct ip_esp_hdr *esph = (struct ip_esp_hdr*)(skb->data+(iph->ihl<<2));
285 struct xfrm_state *x;
287 if (skb->h.icmph->type != ICMP_DEST_UNREACH ||
288 skb->h.icmph->code != ICMP_FRAG_NEEDED)
291 x = xfrm_state_lookup((xfrm_address_t *)&iph->daddr, esph->spi, IPPROTO_ESP, AF_INET);
294 NETDEBUG(KERN_DEBUG "pmtu discovery on SA ESP/%08x/%08x\n",
295 ntohl(esph->spi), ntohl(iph->daddr));
299 static void esp_destroy(struct xfrm_state *x)
301 struct esp_data *esp = x->data;
306 crypto_free_blkcipher(esp->conf.tfm);
307 esp->conf.tfm = NULL;
308 kfree(esp->conf.ivec);
309 esp->conf.ivec = NULL;
310 crypto_free_tfm(esp->auth.tfm);
311 esp->auth.tfm = NULL;
312 kfree(esp->auth.work_icv);
313 esp->auth.work_icv = NULL;
317 static int esp_init_state(struct xfrm_state *x)
319 struct esp_data *esp = NULL;
320 struct crypto_blkcipher *tfm;
322 /* null auth and encryption can have zero length keys */
324 if (x->aalg->alg_key_len > 512)
330 esp = kzalloc(sizeof(*esp), GFP_KERNEL);
335 struct xfrm_algo_desc *aalg_desc;
337 esp->auth.key = x->aalg->alg_key;
338 esp->auth.key_len = (x->aalg->alg_key_len+7)/8;
339 esp->auth.tfm = crypto_alloc_tfm(x->aalg->alg_name, 0);
340 if (esp->auth.tfm == NULL)
342 esp->auth.icv = esp_hmac_digest;
344 aalg_desc = xfrm_aalg_get_byname(x->aalg->alg_name, 0);
347 if (aalg_desc->uinfo.auth.icv_fullbits/8 !=
348 crypto_tfm_alg_digestsize(esp->auth.tfm)) {
349 NETDEBUG(KERN_INFO "ESP: %s digestsize %u != %hu\n",
351 crypto_tfm_alg_digestsize(esp->auth.tfm),
352 aalg_desc->uinfo.auth.icv_fullbits/8);
356 esp->auth.icv_full_len = aalg_desc->uinfo.auth.icv_fullbits/8;
357 esp->auth.icv_trunc_len = aalg_desc->uinfo.auth.icv_truncbits/8;
359 esp->auth.work_icv = kmalloc(esp->auth.icv_full_len, GFP_KERNEL);
360 if (!esp->auth.work_icv)
363 esp->conf.key = x->ealg->alg_key;
364 esp->conf.key_len = (x->ealg->alg_key_len+7)/8;
365 tfm = crypto_alloc_blkcipher(x->ealg->alg_name, 0, CRYPTO_ALG_ASYNC);
369 esp->conf.ivlen = crypto_blkcipher_ivsize(tfm);
370 esp->conf.padlen = 0;
371 if (esp->conf.ivlen) {
372 esp->conf.ivec = kmalloc(esp->conf.ivlen, GFP_KERNEL);
373 if (unlikely(esp->conf.ivec == NULL))
375 get_random_bytes(esp->conf.ivec, esp->conf.ivlen);
377 if (crypto_blkcipher_setkey(tfm, esp->conf.key, esp->conf.key_len))
379 x->props.header_len = sizeof(struct ip_esp_hdr) + esp->conf.ivlen;
381 x->props.header_len += sizeof(struct iphdr);
383 struct xfrm_encap_tmpl *encap = x->encap;
385 switch (encap->encap_type) {
388 case UDP_ENCAP_ESPINUDP:
389 x->props.header_len += sizeof(struct udphdr);
391 case UDP_ENCAP_ESPINUDP_NON_IKE:
392 x->props.header_len += sizeof(struct udphdr) + 2 * sizeof(u32);
397 x->props.trailer_len = esp4_get_max_size(x, 0) - x->props.header_len;
407 static struct xfrm_type esp_type =
409 .description = "ESP4",
410 .owner = THIS_MODULE,
411 .proto = IPPROTO_ESP,
412 .init_state = esp_init_state,
413 .destructor = esp_destroy,
414 .get_max_size = esp4_get_max_size,
419 static struct net_protocol esp4_protocol = {
420 .handler = xfrm4_rcv,
421 .err_handler = esp4_err,
425 static int __init esp4_init(void)
427 if (xfrm_register_type(&esp_type, AF_INET) < 0) {
428 printk(KERN_INFO "ip esp init: can't add xfrm type\n");
431 if (inet_add_protocol(&esp4_protocol, IPPROTO_ESP) < 0) {
432 printk(KERN_INFO "ip esp init: can't add protocol\n");
433 xfrm_unregister_type(&esp_type, AF_INET);
439 static void __exit esp4_fini(void)
441 if (inet_del_protocol(&esp4_protocol, IPPROTO_ESP) < 0)
442 printk(KERN_INFO "ip esp close: can't remove protocol\n");
443 if (xfrm_unregister_type(&esp_type, AF_INET) < 0)
444 printk(KERN_INFO "ip esp close: can't remove xfrm type\n");
447 module_init(esp4_init);
448 module_exit(esp4_fini);
449 MODULE_LICENSE("GPL");