107d4ee58SHerbert Xu #include <linux/err.h> 21da177e4SLinus Torvalds #include <linux/module.h> 31da177e4SLinus Torvalds #include <net/ip.h> 41da177e4SLinus Torvalds #include <net/xfrm.h> 51da177e4SLinus Torvalds #include <net/ah.h> 61da177e4SLinus Torvalds #include <linux/crypto.h> 71da177e4SLinus Torvalds #include <linux/pfkeyv2.h> 8b7c6538cSHerbert Xu #include <linux/spinlock.h> 91da177e4SLinus Torvalds #include <net/icmp.h> 1014c85021SArnaldo Carvalho de Melo #include <net/protocol.h> 111da177e4SLinus Torvalds 121da177e4SLinus Torvalds 131da177e4SLinus Torvalds /* Clear mutable options and find final destination to substitute 141da177e4SLinus Torvalds * into IP header for icv calculation. Options are already checked 151da177e4SLinus Torvalds * for validity, so paranoia is not required. */ 161da177e4SLinus Torvalds 17d5a0a1e3SAl Viro static int ip_clear_mutable_options(struct iphdr *iph, __be32 *daddr) 181da177e4SLinus Torvalds { 191da177e4SLinus Torvalds unsigned char * optptr = (unsigned char*)(iph+1); 201da177e4SLinus Torvalds int l = iph->ihl*4 - sizeof(struct iphdr); 211da177e4SLinus Torvalds int optlen; 221da177e4SLinus Torvalds 231da177e4SLinus Torvalds while (l > 0) { 241da177e4SLinus Torvalds switch (*optptr) { 251da177e4SLinus Torvalds case IPOPT_END: 261da177e4SLinus Torvalds return 0; 271da177e4SLinus Torvalds case IPOPT_NOOP: 281da177e4SLinus Torvalds l--; 291da177e4SLinus Torvalds optptr++; 301da177e4SLinus Torvalds continue; 311da177e4SLinus Torvalds } 321da177e4SLinus Torvalds optlen = optptr[1]; 331da177e4SLinus Torvalds if (optlen<2 || optlen>l) 341da177e4SLinus Torvalds return -EINVAL; 351da177e4SLinus Torvalds switch (*optptr) { 361da177e4SLinus Torvalds case IPOPT_SEC: 371da177e4SLinus Torvalds case 0x85: /* Some "Extended Security" crap. */ 3811a03f78SPaul Moore case IPOPT_CIPSO: 391da177e4SLinus Torvalds case IPOPT_RA: 401da177e4SLinus Torvalds case 0x80|21: /* RFC1770 */ 411da177e4SLinus Torvalds break; 421da177e4SLinus Torvalds case IPOPT_LSRR: 431da177e4SLinus Torvalds case IPOPT_SSRR: 441da177e4SLinus Torvalds if (optlen < 6) 451da177e4SLinus Torvalds return -EINVAL; 461da177e4SLinus Torvalds memcpy(daddr, optptr+optlen-4, 4); 471da177e4SLinus Torvalds /* Fall through */ 481da177e4SLinus Torvalds default: 4996fe1c02SNick Bowler memset(optptr, 0, optlen); 501da177e4SLinus Torvalds } 511da177e4SLinus Torvalds l -= optlen; 521da177e4SLinus Torvalds optptr += optlen; 531da177e4SLinus Torvalds } 541da177e4SLinus Torvalds return 0; 551da177e4SLinus Torvalds } 561da177e4SLinus Torvalds 571da177e4SLinus Torvalds static int ah_output(struct xfrm_state *x, struct sk_buff *skb) 581da177e4SLinus Torvalds { 591da177e4SLinus Torvalds int err; 601da177e4SLinus Torvalds struct iphdr *iph, *top_iph; 611da177e4SLinus Torvalds struct ip_auth_hdr *ah; 621da177e4SLinus Torvalds struct ah_data *ahp; 631da177e4SLinus Torvalds union { 641da177e4SLinus Torvalds struct iphdr iph; 651da177e4SLinus Torvalds char buf[60]; 661da177e4SLinus Torvalds } tmp_iph; 671da177e4SLinus Torvalds 687b277b1aSHerbert Xu skb_push(skb, -skb_network_offset(skb)); 69eddc9ec5SArnaldo Carvalho de Melo top_iph = ip_hdr(skb); 701da177e4SLinus Torvalds iph = &tmp_iph.iph; 711da177e4SLinus Torvalds 721da177e4SLinus Torvalds iph->tos = top_iph->tos; 731da177e4SLinus Torvalds iph->ttl = top_iph->ttl; 741da177e4SLinus Torvalds iph->frag_off = top_iph->frag_off; 751da177e4SLinus Torvalds 761da177e4SLinus Torvalds if (top_iph->ihl != 5) { 771da177e4SLinus Torvalds iph->daddr = top_iph->daddr; 781da177e4SLinus Torvalds memcpy(iph+1, top_iph+1, top_iph->ihl*4 - sizeof(struct iphdr)); 791da177e4SLinus Torvalds err = ip_clear_mutable_options(top_iph, &top_iph->daddr); 801da177e4SLinus Torvalds if (err) 811da177e4SLinus Torvalds goto error; 821da177e4SLinus Torvalds } 831da177e4SLinus Torvalds 8487bdc48dSHerbert Xu ah = ip_auth_hdr(skb); 8537fedd3aSHerbert Xu ah->nexthdr = *skb_mac_header(skb); 8637fedd3aSHerbert Xu *skb_mac_header(skb) = IPPROTO_AH; 871da177e4SLinus Torvalds 881da177e4SLinus Torvalds top_iph->tos = 0; 891da177e4SLinus Torvalds top_iph->tot_len = htons(skb->len); 901da177e4SLinus Torvalds top_iph->frag_off = 0; 911da177e4SLinus Torvalds top_iph->ttl = 0; 921da177e4SLinus Torvalds top_iph->check = 0; 931da177e4SLinus Torvalds 941da177e4SLinus Torvalds ahp = x->data; 9587bdc48dSHerbert Xu ah->hdrlen = (XFRM_ALIGN8(sizeof(*ah) + ahp->icv_trunc_len) >> 2) - 2; 961da177e4SLinus Torvalds 971da177e4SLinus Torvalds ah->reserved = 0; 981da177e4SLinus Torvalds ah->spi = x->id.spi; 99b318e0e4SHerbert Xu ah->seq_no = htonl(XFRM_SKB_CB(skb)->seq.output); 100b7c6538cSHerbert Xu 101b7c6538cSHerbert Xu spin_lock_bh(&x->lock); 10207d4ee58SHerbert Xu err = ah_mac_digest(ahp, skb, ah->auth_data); 103b7c6538cSHerbert Xu memcpy(ah->auth_data, ahp->work_icv, ahp->icv_trunc_len); 104b7c6538cSHerbert Xu spin_unlock_bh(&x->lock); 105b7c6538cSHerbert Xu 10607d4ee58SHerbert Xu if (err) 10707d4ee58SHerbert Xu goto error; 1081da177e4SLinus Torvalds 1091da177e4SLinus Torvalds top_iph->tos = iph->tos; 1101da177e4SLinus Torvalds top_iph->ttl = iph->ttl; 1111da177e4SLinus Torvalds top_iph->frag_off = iph->frag_off; 1121da177e4SLinus Torvalds if (top_iph->ihl != 5) { 1131da177e4SLinus Torvalds top_iph->daddr = iph->daddr; 1141da177e4SLinus Torvalds memcpy(top_iph+1, iph+1, top_iph->ihl*4 - sizeof(struct iphdr)); 1151da177e4SLinus Torvalds } 1161da177e4SLinus Torvalds 1171da177e4SLinus Torvalds err = 0; 1181da177e4SLinus Torvalds 1191da177e4SLinus Torvalds error: 1201da177e4SLinus Torvalds return err; 1211da177e4SLinus Torvalds } 1221da177e4SLinus Torvalds 123e695633eSHerbert Xu static int ah_input(struct xfrm_state *x, struct sk_buff *skb) 1241da177e4SLinus Torvalds { 1251da177e4SLinus Torvalds int ah_hlen; 12631a4ab93SHerbert Xu int ihl; 127631a6698SHerbert Xu int nexthdr; 12807d4ee58SHerbert Xu int err = -EINVAL; 1291da177e4SLinus Torvalds struct iphdr *iph; 1301da177e4SLinus Torvalds struct ip_auth_hdr *ah; 1311da177e4SLinus Torvalds struct ah_data *ahp; 1321da177e4SLinus Torvalds char work_buf[60]; 1331da177e4SLinus Torvalds 13487bdc48dSHerbert Xu if (!pskb_may_pull(skb, sizeof(*ah))) 1351da177e4SLinus Torvalds goto out; 1361da177e4SLinus Torvalds 1371da177e4SLinus Torvalds ah = (struct ip_auth_hdr *)skb->data; 1381da177e4SLinus Torvalds ahp = x->data; 139631a6698SHerbert Xu nexthdr = ah->nexthdr; 1401da177e4SLinus Torvalds ah_hlen = (ah->hdrlen + 2) << 2; 1411da177e4SLinus Torvalds 14287bdc48dSHerbert Xu if (ah_hlen != XFRM_ALIGN8(sizeof(*ah) + ahp->icv_full_len) && 14387bdc48dSHerbert Xu ah_hlen != XFRM_ALIGN8(sizeof(*ah) + ahp->icv_trunc_len)) 1441da177e4SLinus Torvalds goto out; 1451da177e4SLinus Torvalds 1461da177e4SLinus Torvalds if (!pskb_may_pull(skb, ah_hlen)) 1471da177e4SLinus Torvalds goto out; 1481da177e4SLinus Torvalds 1491da177e4SLinus Torvalds /* We are going to _remove_ AH header to keep sockets happy, 1501da177e4SLinus Torvalds * so... Later this can change. */ 1511da177e4SLinus Torvalds if (skb_cloned(skb) && 1521da177e4SLinus Torvalds pskb_expand_head(skb, 0, 0, GFP_ATOMIC)) 1531da177e4SLinus Torvalds goto out; 1541da177e4SLinus Torvalds 1551da177e4SLinus Torvalds skb->ip_summed = CHECKSUM_NONE; 1561da177e4SLinus Torvalds 1571da177e4SLinus Torvalds ah = (struct ip_auth_hdr *)skb->data; 158eddc9ec5SArnaldo Carvalho de Melo iph = ip_hdr(skb); 1591da177e4SLinus Torvalds 160d56f90a7SArnaldo Carvalho de Melo ihl = skb->data - skb_network_header(skb); 16131a4ab93SHerbert Xu memcpy(work_buf, iph, ihl); 1621da177e4SLinus Torvalds 1631da177e4SLinus Torvalds iph->ttl = 0; 1641da177e4SLinus Torvalds iph->tos = 0; 1651da177e4SLinus Torvalds iph->frag_off = 0; 1661da177e4SLinus Torvalds iph->check = 0; 16731a4ab93SHerbert Xu if (ihl > sizeof(*iph)) { 168d5a0a1e3SAl Viro __be32 dummy; 1691da177e4SLinus Torvalds if (ip_clear_mutable_options(iph, &dummy)) 1701da177e4SLinus Torvalds goto out; 1711da177e4SLinus Torvalds } 1720ebea8efSHerbert Xu 1730ebea8efSHerbert Xu spin_lock(&x->lock); 1741da177e4SLinus Torvalds { 1751da177e4SLinus Torvalds u8 auth_data[MAX_AH_AUTH_LEN]; 1761da177e4SLinus Torvalds 1771da177e4SLinus Torvalds memcpy(auth_data, ah->auth_data, ahp->icv_trunc_len); 17831a4ab93SHerbert Xu skb_push(skb, ihl); 17907d4ee58SHerbert Xu err = ah_mac_digest(ahp, skb, ah->auth_data); 18007d4ee58SHerbert Xu if (err) 1810ebea8efSHerbert Xu goto unlock; 1829dd3245aSHerbert Xu if (memcmp(ahp->work_icv, auth_data, ahp->icv_trunc_len)) 183668dc8afSHerbert Xu err = -EBADMSG; 1840ebea8efSHerbert Xu } 1850ebea8efSHerbert Xu unlock: 1860ebea8efSHerbert Xu spin_unlock(&x->lock); 1870ebea8efSHerbert Xu 1880ebea8efSHerbert Xu if (err) 1891da177e4SLinus Torvalds goto out; 1900ebea8efSHerbert Xu 191b0e380b1SArnaldo Carvalho de Melo skb->network_header += ah_hlen; 192badff6d0SArnaldo Carvalho de Melo memcpy(skb_network_header(skb), work_buf, ihl); 193b0e380b1SArnaldo Carvalho de Melo skb->transport_header = skb->network_header; 19431a4ab93SHerbert Xu __skb_pull(skb, ah_hlen + ihl); 1951da177e4SLinus Torvalds 196631a6698SHerbert Xu return nexthdr; 1971da177e4SLinus Torvalds 1981da177e4SLinus Torvalds out: 19907d4ee58SHerbert Xu return err; 2001da177e4SLinus Torvalds } 2011da177e4SLinus Torvalds 2021da177e4SLinus Torvalds static void ah4_err(struct sk_buff *skb, u32 info) 2031da177e4SLinus Torvalds { 2044fb236baSAlexey Dobriyan struct net *net = dev_net(skb->dev); 2051da177e4SLinus Torvalds struct iphdr *iph = (struct iphdr *)skb->data; 2061da177e4SLinus Torvalds struct ip_auth_hdr *ah = (struct ip_auth_hdr *)(skb->data+(iph->ihl<<2)); 2071da177e4SLinus Torvalds struct xfrm_state *x; 2081da177e4SLinus Torvalds 20988c7664fSArnaldo Carvalho de Melo if (icmp_hdr(skb)->type != ICMP_DEST_UNREACH || 21088c7664fSArnaldo Carvalho de Melo icmp_hdr(skb)->code != ICMP_FRAG_NEEDED) 2111da177e4SLinus Torvalds return; 2121da177e4SLinus Torvalds 2134fb236baSAlexey Dobriyan x = xfrm_state_lookup(net, (xfrm_address_t *)&iph->daddr, ah->spi, IPPROTO_AH, AF_INET); 2141da177e4SLinus Torvalds if (!x) 2151da177e4SLinus Torvalds return; 2161da177e4SLinus Torvalds printk(KERN_DEBUG "pmtu discovery on SA AH/%08x/%08x\n", 2171da177e4SLinus Torvalds ntohl(ah->spi), ntohl(iph->daddr)); 2181da177e4SLinus Torvalds xfrm_state_put(x); 2191da177e4SLinus Torvalds } 2201da177e4SLinus Torvalds 22172cb6962SHerbert Xu static int ah_init_state(struct xfrm_state *x) 2221da177e4SLinus Torvalds { 2231da177e4SLinus Torvalds struct ah_data *ahp = NULL; 2241da177e4SLinus Torvalds struct xfrm_algo_desc *aalg_desc; 22507d4ee58SHerbert Xu struct crypto_hash *tfm; 2261da177e4SLinus Torvalds 2271da177e4SLinus Torvalds if (!x->aalg) 2281da177e4SLinus Torvalds goto error; 2291da177e4SLinus Torvalds 2301da177e4SLinus Torvalds if (x->encap) 2311da177e4SLinus Torvalds goto error; 2321da177e4SLinus Torvalds 2330da974f4SPanagiotis Issaris ahp = kzalloc(sizeof(*ahp), GFP_KERNEL); 2341da177e4SLinus Torvalds if (ahp == NULL) 2351da177e4SLinus Torvalds return -ENOMEM; 2361da177e4SLinus Torvalds 23707d4ee58SHerbert Xu tfm = crypto_alloc_hash(x->aalg->alg_name, 0, CRYPTO_ALG_ASYNC); 23807d4ee58SHerbert Xu if (IS_ERR(tfm)) 2391da177e4SLinus Torvalds goto error; 24007d4ee58SHerbert Xu 24107d4ee58SHerbert Xu ahp->tfm = tfm; 242bc31d3b2SHerbert Xu if (crypto_hash_setkey(tfm, x->aalg->alg_key, 243bc31d3b2SHerbert Xu (x->aalg->alg_key_len + 7) / 8)) 24407d4ee58SHerbert Xu goto error; 2451da177e4SLinus Torvalds 2461da177e4SLinus Torvalds /* 2471da177e4SLinus Torvalds * Lookup the algorithm description maintained by xfrm_algo, 2481da177e4SLinus Torvalds * verify crypto transform properties, and store information 2491da177e4SLinus Torvalds * we need for AH processing. This lookup cannot fail here 25007d4ee58SHerbert Xu * after a successful crypto_alloc_hash(). 2511da177e4SLinus Torvalds */ 2521da177e4SLinus Torvalds aalg_desc = xfrm_aalg_get_byname(x->aalg->alg_name, 0); 2531da177e4SLinus Torvalds BUG_ON(!aalg_desc); 2541da177e4SLinus Torvalds 2551da177e4SLinus Torvalds if (aalg_desc->uinfo.auth.icv_fullbits/8 != 25607d4ee58SHerbert Xu crypto_hash_digestsize(tfm)) { 2571da177e4SLinus Torvalds printk(KERN_INFO "AH: %s digestsize %u != %hu\n", 25807d4ee58SHerbert Xu x->aalg->alg_name, crypto_hash_digestsize(tfm), 2591da177e4SLinus Torvalds aalg_desc->uinfo.auth.icv_fullbits/8); 2601da177e4SLinus Torvalds goto error; 2611da177e4SLinus Torvalds } 2621da177e4SLinus Torvalds 2631da177e4SLinus Torvalds ahp->icv_full_len = aalg_desc->uinfo.auth.icv_fullbits/8; 2641da177e4SLinus Torvalds ahp->icv_trunc_len = aalg_desc->uinfo.auth.icv_truncbits/8; 2651da177e4SLinus Torvalds 2661da177e4SLinus Torvalds BUG_ON(ahp->icv_trunc_len > MAX_AH_AUTH_LEN); 2671da177e4SLinus Torvalds 2681da177e4SLinus Torvalds ahp->work_icv = kmalloc(ahp->icv_full_len, GFP_KERNEL); 2691da177e4SLinus Torvalds if (!ahp->work_icv) 2701da177e4SLinus Torvalds goto error; 2711da177e4SLinus Torvalds 27287bdc48dSHerbert Xu x->props.header_len = XFRM_ALIGN8(sizeof(struct ip_auth_hdr) + 27387bdc48dSHerbert Xu ahp->icv_trunc_len); 2747e49e6deSMasahide NAKAMURA if (x->props.mode == XFRM_MODE_TUNNEL) 2751da177e4SLinus Torvalds x->props.header_len += sizeof(struct iphdr); 2761da177e4SLinus Torvalds x->data = ahp; 2771da177e4SLinus Torvalds 2781da177e4SLinus Torvalds return 0; 2791da177e4SLinus Torvalds 2801da177e4SLinus Torvalds error: 2811da177e4SLinus Torvalds if (ahp) { 2821da177e4SLinus Torvalds kfree(ahp->work_icv); 28307d4ee58SHerbert Xu crypto_free_hash(ahp->tfm); 2841da177e4SLinus Torvalds kfree(ahp); 2851da177e4SLinus Torvalds } 2861da177e4SLinus Torvalds return -EINVAL; 2871da177e4SLinus Torvalds } 2881da177e4SLinus Torvalds 2891da177e4SLinus Torvalds static void ah_destroy(struct xfrm_state *x) 2901da177e4SLinus Torvalds { 2911da177e4SLinus Torvalds struct ah_data *ahp = x->data; 2921da177e4SLinus Torvalds 2931da177e4SLinus Torvalds if (!ahp) 2941da177e4SLinus Torvalds return; 2951da177e4SLinus Torvalds 2961da177e4SLinus Torvalds kfree(ahp->work_icv); 29707d4ee58SHerbert Xu crypto_free_hash(ahp->tfm); 2981da177e4SLinus Torvalds kfree(ahp); 2991da177e4SLinus Torvalds } 3001da177e4SLinus Torvalds 3011da177e4SLinus Torvalds 302533cb5b0SEric Dumazet static const struct xfrm_type ah_type = 3031da177e4SLinus Torvalds { 3041da177e4SLinus Torvalds .description = "AH4", 3051da177e4SLinus Torvalds .owner = THIS_MODULE, 3061da177e4SLinus Torvalds .proto = IPPROTO_AH, 307436a0a40SHerbert Xu .flags = XFRM_TYPE_REPLAY_PROT, 3081da177e4SLinus Torvalds .init_state = ah_init_state, 3091da177e4SLinus Torvalds .destructor = ah_destroy, 3101da177e4SLinus Torvalds .input = ah_input, 3111da177e4SLinus Torvalds .output = ah_output 3121da177e4SLinus Torvalds }; 3131da177e4SLinus Torvalds 314*32613090SAlexey Dobriyan static const struct net_protocol ah4_protocol = { 3151da177e4SLinus Torvalds .handler = xfrm4_rcv, 3161da177e4SLinus Torvalds .err_handler = ah4_err, 3171da177e4SLinus Torvalds .no_policy = 1, 3184fb236baSAlexey Dobriyan .netns_ok = 1, 3191da177e4SLinus Torvalds }; 3201da177e4SLinus Torvalds 3211da177e4SLinus Torvalds static int __init ah4_init(void) 3221da177e4SLinus Torvalds { 3231da177e4SLinus Torvalds if (xfrm_register_type(&ah_type, AF_INET) < 0) { 3241da177e4SLinus Torvalds printk(KERN_INFO "ip ah init: can't add xfrm type\n"); 3251da177e4SLinus Torvalds return -EAGAIN; 3261da177e4SLinus Torvalds } 3271da177e4SLinus Torvalds if (inet_add_protocol(&ah4_protocol, IPPROTO_AH) < 0) { 3281da177e4SLinus Torvalds printk(KERN_INFO "ip ah init: can't add protocol\n"); 3291da177e4SLinus Torvalds xfrm_unregister_type(&ah_type, AF_INET); 3301da177e4SLinus Torvalds return -EAGAIN; 3311da177e4SLinus Torvalds } 3321da177e4SLinus Torvalds return 0; 3331da177e4SLinus Torvalds } 3341da177e4SLinus Torvalds 3351da177e4SLinus Torvalds static void __exit ah4_fini(void) 3361da177e4SLinus Torvalds { 3371da177e4SLinus Torvalds if (inet_del_protocol(&ah4_protocol, IPPROTO_AH) < 0) 3381da177e4SLinus Torvalds printk(KERN_INFO "ip ah close: can't remove protocol\n"); 3391da177e4SLinus Torvalds if (xfrm_unregister_type(&ah_type, AF_INET) < 0) 3401da177e4SLinus Torvalds printk(KERN_INFO "ip ah close: can't remove xfrm type\n"); 3411da177e4SLinus Torvalds } 3421da177e4SLinus Torvalds 3431da177e4SLinus Torvalds module_init(ah4_init); 3441da177e4SLinus Torvalds module_exit(ah4_fini); 3451da177e4SLinus Torvalds MODULE_LICENSE("GPL"); 346d3d6dd3aSMasahide NAKAMURA MODULE_ALIAS_XFRM_TYPE(AF_INET, XFRM_PROTO_AH); 347