| #include <linux/err.h> |
| #include <linux/module.h> |
| #include <net/ip.h> |
| #include <net/xfrm.h> |
| #include <net/esp.h> |
| #include <asm/scatterlist.h> |
| #include <linux/crypto.h> |
| #include <linux/kernel.h> |
| #include <linux/pfkeyv2.h> |
| #include <linux/random.h> |
| #include <linux/spinlock.h> |
| #include <net/icmp.h> |
| #include <net/protocol.h> |
| #include <net/udp.h> |
| |
| static int esp_output(struct xfrm_state *x, struct sk_buff *skb) |
| { |
| int err; |
| struct ip_esp_hdr *esph; |
| struct crypto_blkcipher *tfm; |
| struct blkcipher_desc desc; |
| struct esp_data *esp; |
| struct sk_buff *trailer; |
| u8 *tail; |
| int blksize; |
| int clen; |
| int alen; |
| int nfrags; |
| |
| /* skb is pure payload to encrypt */ |
| |
| err = -ENOMEM; |
| |
| /* Round to block size */ |
| clen = skb->len; |
| |
| esp = x->data; |
| alen = esp->auth.icv_trunc_len; |
| tfm = esp->conf.tfm; |
| desc.tfm = tfm; |
| desc.flags = 0; |
| blksize = ALIGN(crypto_blkcipher_blocksize(tfm), 4); |
| clen = ALIGN(clen + 2, blksize); |
| if (esp->conf.padlen) |
| clen = ALIGN(clen, esp->conf.padlen); |
| |
| if ((nfrags = skb_cow_data(skb, clen-skb->len+alen, &trailer)) < 0) |
| goto error; |
| |
| /* Fill padding... */ |
| tail = skb_tail_pointer(trailer); |
| do { |
| int i; |
| for (i=0; i<clen-skb->len - 2; i++) |
| tail[i] = i + 1; |
| } while (0); |
| tail[clen - skb->len - 2] = (clen - skb->len) - 2; |
| pskb_put(skb, trailer, clen - skb->len); |
| |
| skb_push(skb, -skb_network_offset(skb)); |
| esph = ip_esp_hdr(skb); |
| *(skb_tail_pointer(trailer) - 1) = *skb_mac_header(skb); |
| *skb_mac_header(skb) = IPPROTO_ESP; |
| |
| spin_lock_bh(&x->lock); |
| |
| /* this is non-NULL only with UDP Encapsulation */ |
| if (x->encap) { |
| struct xfrm_encap_tmpl *encap = x->encap; |
| struct udphdr *uh; |
| __be32 *udpdata32; |
| |
| uh = (struct udphdr *)esph; |
| uh->source = encap->encap_sport; |
| uh->dest = encap->encap_dport; |
| uh->len = htons(skb->len + alen - skb_transport_offset(skb)); |
| uh->check = 0; |
| |
| switch (encap->encap_type) { |
| default: |
| case UDP_ENCAP_ESPINUDP: |
| esph = (struct ip_esp_hdr *)(uh + 1); |
| break; |
| case UDP_ENCAP_ESPINUDP_NON_IKE: |
| udpdata32 = (__be32 *)(uh + 1); |
| udpdata32[0] = udpdata32[1] = 0; |
| esph = (struct ip_esp_hdr *)(udpdata32 + 2); |
| break; |
| } |
| |
| *skb_mac_header(skb) = IPPROTO_UDP; |
| } |
| |
| esph->spi = x->id.spi; |
| esph->seq_no = htonl(XFRM_SKB_CB(skb)->seq); |
| |
| if (esp->conf.ivlen) { |
| if (unlikely(!esp->conf.ivinitted)) { |
| get_random_bytes(esp->conf.ivec, esp->conf.ivlen); |
| esp->conf.ivinitted = 1; |
| } |
| crypto_blkcipher_set_iv(tfm, esp->conf.ivec, esp->conf.ivlen); |
| } |
| |
| do { |
| struct scatterlist *sg = &esp->sgbuf[0]; |
| |
| if (unlikely(nfrags > ESP_NUM_FAST_SG)) { |
| sg = kmalloc(sizeof(struct scatterlist)*nfrags, GFP_ATOMIC); |
| if (!sg) |
| goto unlock; |
| } |
| sg_init_table(sg, nfrags); |
| skb_to_sgvec(skb, sg, esph->enc_data+esp->conf.ivlen-skb->data, clen); |
| err = crypto_blkcipher_encrypt(&desc, sg, sg, clen); |
| if (unlikely(sg != &esp->sgbuf[0])) |
| kfree(sg); |
| } while (0); |
| |
| if (unlikely(err)) |
| goto unlock; |
| |
| if (esp->conf.ivlen) { |
| memcpy(esph->enc_data, esp->conf.ivec, esp->conf.ivlen); |
| crypto_blkcipher_get_iv(tfm, esp->conf.ivec, esp->conf.ivlen); |
| } |
| |
| if (esp->auth.icv_full_len) { |
| err = esp_mac_digest(esp, skb, (u8 *)esph - skb->data, |
| sizeof(*esph) + esp->conf.ivlen + clen); |
| memcpy(pskb_put(skb, trailer, alen), esp->auth.work_icv, alen); |
| } |
| |
| unlock: |
| spin_unlock_bh(&x->lock); |
| |
| error: |
| return err; |
| } |
| |
| /* |
| * Note: detecting truncated vs. non-truncated authentication data is very |
| * expensive, so we only support truncated data, which is the recommended |
| * and common case. |
| */ |
| static int esp_input(struct xfrm_state *x, struct sk_buff *skb) |
| { |
| struct iphdr *iph; |
| struct ip_esp_hdr *esph; |
| struct esp_data *esp = x->data; |
| struct crypto_blkcipher *tfm = esp->conf.tfm; |
| struct blkcipher_desc desc = { .tfm = tfm }; |
| struct sk_buff *trailer; |
| int blksize = ALIGN(crypto_blkcipher_blocksize(tfm), 4); |
| int alen = esp->auth.icv_trunc_len; |
| int elen = skb->len - sizeof(*esph) - esp->conf.ivlen - alen; |
| int nfrags; |
| int ihl; |
| u8 nexthdr[2]; |
| struct scatterlist *sg; |
| int padlen; |
| int err; |
| |
| if (!pskb_may_pull(skb, sizeof(*esph))) |
| goto out; |
| |
| if (elen <= 0 || (elen & (blksize-1))) |
| goto out; |
| |
| /* If integrity check is required, do this. */ |
| if (esp->auth.icv_full_len) { |
| u8 sum[alen]; |
| |
| err = esp_mac_digest(esp, skb, 0, skb->len - alen); |
| if (err) |
| goto out; |
| |
| if (skb_copy_bits(skb, skb->len - alen, sum, alen)) |
| BUG(); |
| |
| if (unlikely(memcmp(esp->auth.work_icv, sum, alen))) { |
| x->stats.integrity_failed++; |
| goto out; |
| } |
| } |
| |
| if ((nfrags = skb_cow_data(skb, 0, &trailer)) < 0) |
| goto out; |
| |
| skb->ip_summed = CHECKSUM_NONE; |
| |
| esph = (struct ip_esp_hdr *)skb->data; |
| |
| /* Get ivec. This can be wrong, check against another impls. */ |
| if (esp->conf.ivlen) |
| crypto_blkcipher_set_iv(tfm, esph->enc_data, esp->conf.ivlen); |
| |
| sg = &esp->sgbuf[0]; |
| |
| if (unlikely(nfrags > ESP_NUM_FAST_SG)) { |
| sg = kmalloc(sizeof(struct scatterlist)*nfrags, GFP_ATOMIC); |
| if (!sg) |
| goto out; |
| } |
| sg_init_table(sg, nfrags); |
| skb_to_sgvec(skb, sg, sizeof(*esph) + esp->conf.ivlen, elen); |
| err = crypto_blkcipher_decrypt(&desc, sg, sg, elen); |
| if (unlikely(sg != &esp->sgbuf[0])) |
| kfree(sg); |
| if (unlikely(err)) |
| return err; |
| |
| if (skb_copy_bits(skb, skb->len-alen-2, nexthdr, 2)) |
| BUG(); |
| |
| padlen = nexthdr[0]; |
| if (padlen+2 >= elen) |
| goto out; |
| |
| /* ... check padding bits here. Silly. :-) */ |
| |
| iph = ip_hdr(skb); |
| ihl = iph->ihl * 4; |
| |
| if (x->encap) { |
| struct xfrm_encap_tmpl *encap = x->encap; |
| struct udphdr *uh = (void *)(skb_network_header(skb) + ihl); |
| |
| /* |
| * 1) if the NAT-T peer's IP or port changed then |
| * advertize the change to the keying daemon. |
| * This is an inbound SA, so just compare |
| * SRC ports. |
| */ |
| if (iph->saddr != x->props.saddr.a4 || |
| uh->source != encap->encap_sport) { |
| xfrm_address_t ipaddr; |
| |
| ipaddr.a4 = iph->saddr; |
| km_new_mapping(x, &ipaddr, uh->source); |
| |
| /* XXX: perhaps add an extra |
| * policy check here, to see |
| * if we should allow or |
| * reject a packet from a |
| * different source |
| * address/port. |
| */ |
| } |
| |
| /* |
| * 2) ignore UDP/TCP checksums in case |
| * of NAT-T in Transport Mode, or |
| * perform other post-processing fixes |
| * as per draft-ietf-ipsec-udp-encaps-06, |
| * section 3.1.2 |
| */ |
| if (x->props.mode == XFRM_MODE_TRANSPORT) |
| skb->ip_summed = CHECKSUM_UNNECESSARY; |
| } |
| |
| pskb_trim(skb, skb->len - alen - padlen - 2); |
| __skb_pull(skb, sizeof(*esph) + esp->conf.ivlen); |
| skb_set_transport_header(skb, -ihl); |
| |
| return nexthdr[1]; |
| |
| out: |
| return -EINVAL; |
| } |
| |
| static u32 esp4_get_mtu(struct xfrm_state *x, int mtu) |
| { |
| struct esp_data *esp = x->data; |
| u32 blksize = ALIGN(crypto_blkcipher_blocksize(esp->conf.tfm), 4); |
| u32 align = max_t(u32, blksize, esp->conf.padlen); |
| u32 rem; |
| |
| mtu -= x->props.header_len + esp->auth.icv_trunc_len; |
| rem = mtu & (align - 1); |
| mtu &= ~(align - 1); |
| |
| switch (x->props.mode) { |
| case XFRM_MODE_TUNNEL: |
| break; |
| default: |
| case XFRM_MODE_TRANSPORT: |
| /* The worst case */ |
| mtu -= blksize - 4; |
| mtu += min_t(u32, blksize - 4, rem); |
| break; |
| case XFRM_MODE_BEET: |
| /* The worst case. */ |
| mtu += min_t(u32, IPV4_BEET_PHMAXLEN, rem); |
| break; |
| } |
| |
| return mtu - 2; |
| } |
| |
| static void esp4_err(struct sk_buff *skb, u32 info) |
| { |
| struct iphdr *iph = (struct iphdr*)skb->data; |
| struct ip_esp_hdr *esph = (struct ip_esp_hdr*)(skb->data+(iph->ihl<<2)); |
| struct xfrm_state *x; |
| |
| if (icmp_hdr(skb)->type != ICMP_DEST_UNREACH || |
| icmp_hdr(skb)->code != ICMP_FRAG_NEEDED) |
| return; |
| |
| x = xfrm_state_lookup((xfrm_address_t *)&iph->daddr, esph->spi, IPPROTO_ESP, AF_INET); |
| if (!x) |
| return; |
| NETDEBUG(KERN_DEBUG "pmtu discovery on SA ESP/%08x/%08x\n", |
| ntohl(esph->spi), ntohl(iph->daddr)); |
| xfrm_state_put(x); |
| } |
| |
| static void esp_destroy(struct xfrm_state *x) |
| { |
| struct esp_data *esp = x->data; |
| |
| if (!esp) |
| return; |
| |
| crypto_free_blkcipher(esp->conf.tfm); |
| esp->conf.tfm = NULL; |
| kfree(esp->conf.ivec); |
| esp->conf.ivec = NULL; |
| crypto_free_hash(esp->auth.tfm); |
| esp->auth.tfm = NULL; |
| kfree(esp->auth.work_icv); |
| esp->auth.work_icv = NULL; |
| kfree(esp); |
| } |
| |
| static int esp_init_state(struct xfrm_state *x) |
| { |
| struct esp_data *esp = NULL; |
| struct crypto_blkcipher *tfm; |
| u32 align; |
| |
| if (x->ealg == NULL) |
| goto error; |
| |
| esp = kzalloc(sizeof(*esp), GFP_KERNEL); |
| if (esp == NULL) |
| return -ENOMEM; |
| |
| if (x->aalg) { |
| struct xfrm_algo_desc *aalg_desc; |
| struct crypto_hash *hash; |
| |
| hash = crypto_alloc_hash(x->aalg->alg_name, 0, |
| CRYPTO_ALG_ASYNC); |
| if (IS_ERR(hash)) |
| goto error; |
| |
| esp->auth.tfm = hash; |
| if (crypto_hash_setkey(hash, x->aalg->alg_key, |
| (x->aalg->alg_key_len + 7) / 8)) |
| goto error; |
| |
| aalg_desc = xfrm_aalg_get_byname(x->aalg->alg_name, 0); |
| BUG_ON(!aalg_desc); |
| |
| if (aalg_desc->uinfo.auth.icv_fullbits/8 != |
| crypto_hash_digestsize(hash)) { |
| NETDEBUG(KERN_INFO "ESP: %s digestsize %u != %hu\n", |
| x->aalg->alg_name, |
| crypto_hash_digestsize(hash), |
| aalg_desc->uinfo.auth.icv_fullbits/8); |
| goto error; |
| } |
| |
| esp->auth.icv_full_len = aalg_desc->uinfo.auth.icv_fullbits/8; |
| esp->auth.icv_trunc_len = aalg_desc->uinfo.auth.icv_truncbits/8; |
| |
| esp->auth.work_icv = kmalloc(esp->auth.icv_full_len, GFP_KERNEL); |
| if (!esp->auth.work_icv) |
| goto error; |
| } |
| |
| tfm = crypto_alloc_blkcipher(x->ealg->alg_name, 0, CRYPTO_ALG_ASYNC); |
| if (IS_ERR(tfm)) |
| goto error; |
| esp->conf.tfm = tfm; |
| esp->conf.ivlen = crypto_blkcipher_ivsize(tfm); |
| esp->conf.padlen = 0; |
| if (esp->conf.ivlen) { |
| esp->conf.ivec = kmalloc(esp->conf.ivlen, GFP_KERNEL); |
| if (unlikely(esp->conf.ivec == NULL)) |
| goto error; |
| esp->conf.ivinitted = 0; |
| } |
| if (crypto_blkcipher_setkey(tfm, x->ealg->alg_key, |
| (x->ealg->alg_key_len + 7) / 8)) |
| goto error; |
| x->props.header_len = sizeof(struct ip_esp_hdr) + esp->conf.ivlen; |
| if (x->props.mode == XFRM_MODE_TUNNEL) |
| x->props.header_len += sizeof(struct iphdr); |
| else if (x->props.mode == XFRM_MODE_BEET) |
| x->props.header_len += IPV4_BEET_PHMAXLEN; |
| if (x->encap) { |
| struct xfrm_encap_tmpl *encap = x->encap; |
| |
| switch (encap->encap_type) { |
| default: |
| goto error; |
| case UDP_ENCAP_ESPINUDP: |
| x->props.header_len += sizeof(struct udphdr); |
| break; |
| case UDP_ENCAP_ESPINUDP_NON_IKE: |
| x->props.header_len += sizeof(struct udphdr) + 2 * sizeof(u32); |
| break; |
| } |
| } |
| x->data = esp; |
| align = ALIGN(crypto_blkcipher_blocksize(esp->conf.tfm), 4); |
| if (esp->conf.padlen) |
| align = max_t(u32, align, esp->conf.padlen); |
| x->props.trailer_len = align + 1 + esp->auth.icv_trunc_len; |
| return 0; |
| |
| error: |
| x->data = esp; |
| esp_destroy(x); |
| x->data = NULL; |
| return -EINVAL; |
| } |
| |
| static struct xfrm_type esp_type = |
| { |
| .description = "ESP4", |
| .owner = THIS_MODULE, |
| .proto = IPPROTO_ESP, |
| .flags = XFRM_TYPE_REPLAY_PROT, |
| .init_state = esp_init_state, |
| .destructor = esp_destroy, |
| .get_mtu = esp4_get_mtu, |
| .input = esp_input, |
| .output = esp_output |
| }; |
| |
| static struct net_protocol esp4_protocol = { |
| .handler = xfrm4_rcv, |
| .err_handler = esp4_err, |
| .no_policy = 1, |
| }; |
| |
| static int __init esp4_init(void) |
| { |
| if (xfrm_register_type(&esp_type, AF_INET) < 0) { |
| printk(KERN_INFO "ip esp init: can't add xfrm type\n"); |
| return -EAGAIN; |
| } |
| if (inet_add_protocol(&esp4_protocol, IPPROTO_ESP) < 0) { |
| printk(KERN_INFO "ip esp init: can't add protocol\n"); |
| xfrm_unregister_type(&esp_type, AF_INET); |
| return -EAGAIN; |
| } |
| return 0; |
| } |
| |
| static void __exit esp4_fini(void) |
| { |
| if (inet_del_protocol(&esp4_protocol, IPPROTO_ESP) < 0) |
| printk(KERN_INFO "ip esp close: can't remove protocol\n"); |
| if (xfrm_unregister_type(&esp_type, AF_INET) < 0) |
| printk(KERN_INFO "ip esp close: can't remove xfrm type\n"); |
| } |
| |
| module_init(esp4_init); |
| module_exit(esp4_fini); |
| MODULE_LICENSE("GPL"); |
| MODULE_ALIAS_XFRM_TYPE(AF_INET, XFRM_PROTO_ESP); |