/* * Copyright (C)2002 USAGI/WIDE Project * * This program is free software; you can redistribute it and/or modify * it under the terms of the GNU General Public License as published by * the Free Software Foundation; either version 2 of the License, or * (at your option) any later version. * * This program is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the * GNU General Public License for more details. * * You should have received a copy of the GNU General Public License * along with this program; if not, write to the Free Software * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA * * Authors * * Mitsuru KANDA @USAGI : IPv6 Support * Kazunori MIYAZAWA @USAGI : * Kunihiro Ishiguro <kunihiro@ipinfusion.com> * * This file is derived from net/ipv4/esp.c */ #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 <net/icmp.h> #include <net/ipv6.h> #include <net/protocol.h> #include <linux/icmpv6.h> static int esp6_output(struct xfrm_state *x, struct sk_buff *skb) { int err; struct ipv6hdr *top_iph; struct ipv6_esp_hdr *esph; struct crypto_blkcipher *tfm; struct blkcipher_desc desc; struct sk_buff *trailer; int blksize; int clen; int alen; int nfrags; u8 *tail; struct esp_data *esp = x->data; int hdr_len = (skb_transport_offset(skb) + sizeof(*esph) + esp->conf.ivlen); /* Strip IP+ESP header. */ __skb_pull(skb, hdr_len); /* Now skb is pure payload to encrypt */ err = -ENOMEM; /* Round to block size */ clen = skb->len; 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); top_iph = (struct ipv6hdr *)__skb_push(skb, hdr_len); esph = (struct ipv6_esp_hdr *)skb_transport_header(skb); top_iph->payload_len = htons(skb->len + alen - sizeof(*top_iph)); *(skb_tail_pointer(trailer) - 1) = *skb_network_header(skb); *skb_network_header(skb) = IPPROTO_ESP; esph->spi = x->id.spi; esph->seq_no = htonl(++x->replay.oseq); xfrm_aevent_doreplay(x); 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 error; } 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 error; 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); } error: return err; } static int esp6_input(struct xfrm_state *x, struct sk_buff *skb) { struct ipv6hdr *iph; struct ipv6_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(struct ipv6_esp_hdr) - esp->conf.ivlen - alen; int hdr_len = skb_network_header_len(skb); int nfrags; int ret = 0; if (!pskb_may_pull(skb, sizeof(struct ipv6_esp_hdr))) { ret = -EINVAL; goto out; } if (elen <= 0 || (elen & (blksize-1))) { ret = -EINVAL; goto out; } /* If integrity check is required, do this. */ if (esp->auth.icv_full_len) { u8 sum[alen]; ret = esp_mac_digest(esp, skb, 0, skb->len - alen); if (ret) 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++; ret = -EINVAL; goto out; } } if ((nfrags = skb_cow_data(skb, 0, &trailer)) < 0) { ret = -EINVAL; goto out; } skb->ip_summed = CHECKSUM_NONE; esph = (struct ipv6_esp_hdr*)skb->data; iph = ipv6_hdr(skb); /* 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); { u8 nexthdr[2]; struct scatterlist *sg = &esp->sgbuf[0]; u8 padlen; if (unlikely(nfrags > ESP_NUM_FAST_SG)) { sg = kmalloc(sizeof(struct scatterlist)*nfrags, GFP_ATOMIC); if (!sg) { ret = -ENOMEM; goto out; } } skb_to_sgvec(skb, sg, sizeof(struct ipv6_esp_hdr) + esp->conf.ivlen, elen); ret = crypto_blkcipher_decrypt(&desc, sg, sg, elen); if (unlikely(sg != &esp->sgbuf[0])) kfree(sg); if (unlikely(ret)) goto out; if (skb_copy_bits(skb, skb->len-alen-2, nexthdr, 2)) BUG(); padlen = nexthdr[0]; if (padlen+2 >= elen) { LIMIT_NETDEBUG(KERN_WARNING "ipsec esp packet is garbage padlen=%d, elen=%d\n", padlen+2, elen); ret = -EINVAL; goto out; } /* ... check padding bits here. Silly. :-) */ pskb_trim(skb, skb->len - alen - padlen - 2); ret = nexthdr[1]; } __skb_pull(skb, sizeof(*esph) + esp->conf.ivlen); skb_set_transport_header(skb, -hdr_len); out: return ret; } static u32 esp6_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); if (x->props.mode != XFRM_MODE_TUNNEL) { u32 padsize = ((blksize - 1) & 7) + 1; mtu -= blksize - padsize; mtu += min_t(u32, blksize - padsize, rem); } return mtu - 2; } static void esp6_err(struct sk_buff *skb, struct inet6_skb_parm *opt, int type, int code, int offset, __be32 info) { struct ipv6hdr *iph = (struct ipv6hdr*)skb->data; struct ipv6_esp_hdr *esph = (struct ipv6_esp_hdr*)(skb->data+offset); struct xfrm_state *x; if (type != ICMPV6_DEST_UNREACH && type != ICMPV6_PKT_TOOBIG) return; x = xfrm_state_lookup((xfrm_address_t *)&iph->daddr, esph->spi, IPPROTO_ESP, AF_INET6); if (!x) return; printk(KERN_DEBUG "pmtu discovery on SA ESP/%08x/" NIP6_FMT "\n", ntohl(esph->spi), NIP6(iph->daddr)); xfrm_state_put(x); } static void esp6_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 esp6_init_state(struct xfrm_state *x) { struct esp_data *esp = NULL; struct crypto_blkcipher *tfm; /* null auth and encryption can have zero length keys */ if (x->aalg) { if (x->aalg->alg_key_len > 512) goto error; } if (x->ealg == NULL) goto error; if (x->encap) 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; esp->auth.key = x->aalg->alg_key; esp->auth.key_len = (x->aalg->alg_key_len+7)/8; 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, esp->auth.key, esp->auth.key_len)) 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; } esp->conf.key = x->ealg->alg_key; esp->conf.key_len = (x->ealg->alg_key_len+7)/8; 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, esp->conf.key, esp->conf.key_len)) goto error; x->props.header_len = sizeof(struct ipv6_esp_hdr) + esp->conf.ivlen; if (x->props.mode == XFRM_MODE_TUNNEL) x->props.header_len += sizeof(struct ipv6hdr); x->data = esp; return 0; error: x->data = esp; esp6_destroy(x); x->data = NULL; return -EINVAL; } static struct xfrm_type esp6_type = { .description = "ESP6", .owner = THIS_MODULE, .proto = IPPROTO_ESP, .init_state = esp6_init_state, .destructor = esp6_destroy, .get_mtu = esp6_get_mtu, .input = esp6_input, .output = esp6_output, .hdr_offset = xfrm6_find_1stfragopt, }; static struct inet6_protocol esp6_protocol = { .handler = xfrm6_rcv, .err_handler = esp6_err, .flags = INET6_PROTO_NOPOLICY, }; static int __init esp6_init(void) { if (xfrm_register_type(&esp6_type, AF_INET6) < 0) { printk(KERN_INFO "ipv6 esp init: can't add xfrm type\n"); return -EAGAIN; } if (inet6_add_protocol(&esp6_protocol, IPPROTO_ESP) < 0) { printk(KERN_INFO "ipv6 esp init: can't add protocol\n"); xfrm_unregister_type(&esp6_type, AF_INET6); return -EAGAIN; } return 0; } static void __exit esp6_fini(void) { if (inet6_del_protocol(&esp6_protocol, IPPROTO_ESP) < 0) printk(KERN_INFO "ipv6 esp close: can't remove protocol\n"); if (xfrm_unregister_type(&esp6_type, AF_INET6) < 0) printk(KERN_INFO "ipv6 esp close: can't remove xfrm type\n"); } module_init(esp6_init); module_exit(esp6_fini); MODULE_LICENSE("GPL");