2 #include <linux/module.h>
6 #include <linux/crypto.h>
7 #include <linux/pfkeyv2.h>
8 #include <linux/spinlock.h>
10 #include <net/protocol.h>
11 #include <asm/scatterlist.h>
14 /* Clear mutable options and find final destination to substitute
15 * into IP header for icv calculation. Options are already checked
16 * for validity, so paranoia is not required. */
18 static int ip_clear_mutable_options(struct iphdr *iph, __be32 *daddr)
20 unsigned char * optptr = (unsigned char*)(iph+1);
21 int l = iph->ihl*4 - sizeof(struct iphdr);
34 if (optlen<2 || optlen>l)
38 case 0x85: /* Some "Extended Security" crap. */
41 case 0x80|21: /* RFC1770 */
47 memcpy(daddr, optptr+optlen-4, 4);
50 memset(optptr, 0, optlen);
58 static int ah_output(struct xfrm_state *x, struct sk_buff *skb)
61 struct iphdr *iph, *top_iph;
62 struct ip_auth_hdr *ah;
69 skb_push(skb, -skb_network_offset(skb));
70 top_iph = ip_hdr(skb);
73 iph->tos = top_iph->tos;
74 iph->ttl = top_iph->ttl;
75 iph->frag_off = top_iph->frag_off;
77 if (top_iph->ihl != 5) {
78 iph->daddr = top_iph->daddr;
79 memcpy(iph+1, top_iph+1, top_iph->ihl*4 - sizeof(struct iphdr));
80 err = ip_clear_mutable_options(top_iph, &top_iph->daddr);
85 ah = (struct ip_auth_hdr *)((char *)top_iph+top_iph->ihl*4);
86 ah->nexthdr = top_iph->protocol;
89 top_iph->tot_len = htons(skb->len);
90 top_iph->frag_off = 0;
92 top_iph->protocol = IPPROTO_AH;
96 ah->hdrlen = (XFRM_ALIGN8(sizeof(struct ip_auth_hdr) +
97 ahp->icv_trunc_len) >> 2) - 2;
101 ah->seq_no = htonl(XFRM_SKB_CB(skb)->seq);
103 spin_lock_bh(&x->lock);
104 err = ah_mac_digest(ahp, skb, ah->auth_data);
105 memcpy(ah->auth_data, ahp->work_icv, ahp->icv_trunc_len);
106 spin_unlock_bh(&x->lock);
111 top_iph->tos = iph->tos;
112 top_iph->ttl = iph->ttl;
113 top_iph->frag_off = iph->frag_off;
114 if (top_iph->ihl != 5) {
115 top_iph->daddr = iph->daddr;
116 memcpy(top_iph+1, iph+1, top_iph->ihl*4 - sizeof(struct iphdr));
119 ip_send_check(top_iph);
127 static int ah_input(struct xfrm_state *x, struct sk_buff *skb)
133 struct ip_auth_hdr *ah;
137 if (!pskb_may_pull(skb, sizeof(struct ip_auth_hdr)))
140 ah = (struct ip_auth_hdr*)skb->data;
142 ah_hlen = (ah->hdrlen + 2) << 2;
144 if (ah_hlen != XFRM_ALIGN8(sizeof(struct ip_auth_hdr) + ahp->icv_full_len) &&
145 ah_hlen != XFRM_ALIGN8(sizeof(struct ip_auth_hdr) + ahp->icv_trunc_len))
148 if (!pskb_may_pull(skb, ah_hlen))
151 /* We are going to _remove_ AH header to keep sockets happy,
152 * so... Later this can change. */
153 if (skb_cloned(skb) &&
154 pskb_expand_head(skb, 0, 0, GFP_ATOMIC))
157 skb->ip_summed = CHECKSUM_NONE;
159 ah = (struct ip_auth_hdr*)skb->data;
162 ihl = skb->data - skb_network_header(skb);
163 memcpy(work_buf, iph, ihl);
169 if (ihl > sizeof(*iph)) {
171 if (ip_clear_mutable_options(iph, &dummy))
175 u8 auth_data[MAX_AH_AUTH_LEN];
177 memcpy(auth_data, ah->auth_data, ahp->icv_trunc_len);
179 err = ah_mac_digest(ahp, skb, ah->auth_data);
183 if (memcmp(ahp->work_icv, auth_data, ahp->icv_trunc_len)) {
184 x->stats.integrity_failed++;
188 ((struct iphdr*)work_buf)->protocol = ah->nexthdr;
189 skb->network_header += ah_hlen;
190 memcpy(skb_network_header(skb), work_buf, ihl);
191 skb->transport_header = skb->network_header;
192 __skb_pull(skb, ah_hlen + ihl);
200 static void ah4_err(struct sk_buff *skb, u32 info)
202 struct iphdr *iph = (struct iphdr*)skb->data;
203 struct ip_auth_hdr *ah = (struct ip_auth_hdr*)(skb->data+(iph->ihl<<2));
204 struct xfrm_state *x;
206 if (icmp_hdr(skb)->type != ICMP_DEST_UNREACH ||
207 icmp_hdr(skb)->code != ICMP_FRAG_NEEDED)
210 x = xfrm_state_lookup((xfrm_address_t *)&iph->daddr, ah->spi, IPPROTO_AH, AF_INET);
213 printk(KERN_DEBUG "pmtu discovery on SA AH/%08x/%08x\n",
214 ntohl(ah->spi), ntohl(iph->daddr));
218 static int ah_init_state(struct xfrm_state *x)
220 struct ah_data *ahp = NULL;
221 struct xfrm_algo_desc *aalg_desc;
222 struct crypto_hash *tfm;
230 ahp = kzalloc(sizeof(*ahp), GFP_KERNEL);
234 tfm = crypto_alloc_hash(x->aalg->alg_name, 0, CRYPTO_ALG_ASYNC);
239 if (crypto_hash_setkey(tfm, x->aalg->alg_key,
240 (x->aalg->alg_key_len + 7) / 8))
244 * Lookup the algorithm description maintained by xfrm_algo,
245 * verify crypto transform properties, and store information
246 * we need for AH processing. This lookup cannot fail here
247 * after a successful crypto_alloc_hash().
249 aalg_desc = xfrm_aalg_get_byname(x->aalg->alg_name, 0);
252 if (aalg_desc->uinfo.auth.icv_fullbits/8 !=
253 crypto_hash_digestsize(tfm)) {
254 printk(KERN_INFO "AH: %s digestsize %u != %hu\n",
255 x->aalg->alg_name, crypto_hash_digestsize(tfm),
256 aalg_desc->uinfo.auth.icv_fullbits/8);
260 ahp->icv_full_len = aalg_desc->uinfo.auth.icv_fullbits/8;
261 ahp->icv_trunc_len = aalg_desc->uinfo.auth.icv_truncbits/8;
263 BUG_ON(ahp->icv_trunc_len > MAX_AH_AUTH_LEN);
265 ahp->work_icv = kmalloc(ahp->icv_full_len, GFP_KERNEL);
269 x->props.header_len = XFRM_ALIGN8(sizeof(struct ip_auth_hdr) + ahp->icv_trunc_len);
270 if (x->props.mode == XFRM_MODE_TUNNEL)
271 x->props.header_len += sizeof(struct iphdr);
278 kfree(ahp->work_icv);
279 crypto_free_hash(ahp->tfm);
285 static void ah_destroy(struct xfrm_state *x)
287 struct ah_data *ahp = x->data;
292 kfree(ahp->work_icv);
293 ahp->work_icv = NULL;
294 crypto_free_hash(ahp->tfm);
300 static struct xfrm_type ah_type =
302 .description = "AH4",
303 .owner = THIS_MODULE,
305 .flags = XFRM_TYPE_REPLAY_PROT,
306 .init_state = ah_init_state,
307 .destructor = ah_destroy,
312 static struct net_protocol ah4_protocol = {
313 .handler = xfrm4_rcv,
314 .err_handler = ah4_err,
318 static int __init ah4_init(void)
320 if (xfrm_register_type(&ah_type, AF_INET) < 0) {
321 printk(KERN_INFO "ip ah init: can't add xfrm type\n");
324 if (inet_add_protocol(&ah4_protocol, IPPROTO_AH) < 0) {
325 printk(KERN_INFO "ip ah init: can't add protocol\n");
326 xfrm_unregister_type(&ah_type, AF_INET);
332 static void __exit ah4_fini(void)
334 if (inet_del_protocol(&ah4_protocol, IPPROTO_AH) < 0)
335 printk(KERN_INFO "ip ah close: can't remove protocol\n");
336 if (xfrm_unregister_type(&ah_type, AF_INET) < 0)
337 printk(KERN_INFO "ip ah close: can't remove xfrm type\n");
340 module_init(ah4_init);
341 module_exit(ah4_fini);
342 MODULE_LICENSE("GPL");
343 MODULE_ALIAS_XFRM_TYPE(AF_INET, XFRM_PROTO_AH);