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-rw-r--r--net/ipv6/ah6.c478
1 files changed, 478 insertions, 0 deletions
diff --git a/net/ipv6/ah6.c b/net/ipv6/ah6.c
new file mode 100644
index 0000000..e3ecf62
--- /dev/null
+++ b/net/ipv6/ah6.c
@@ -0,0 +1,478 @@
+/*
+ * 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/ah.c.
+ */
+
+#include <linux/config.h>
+#include <linux/module.h>
+#include <net/ip.h>
+#include <net/ah.h>
+#include <linux/crypto.h>
+#include <linux/pfkeyv2.h>
+#include <linux/string.h>
+#include <net/icmp.h>
+#include <net/ipv6.h>
+#include <net/xfrm.h>
+#include <asm/scatterlist.h>
+
+static int zero_out_mutable_opts(struct ipv6_opt_hdr *opthdr)
+{
+ u8 *opt = (u8 *)opthdr;
+ int len = ipv6_optlen(opthdr);
+ int off = 0;
+ int optlen = 0;
+
+ off += 2;
+ len -= 2;
+
+ while (len > 0) {
+
+ switch (opt[off]) {
+
+ case IPV6_TLV_PAD0:
+ optlen = 1;
+ break;
+ default:
+ if (len < 2)
+ goto bad;
+ optlen = opt[off+1]+2;
+ if (len < optlen)
+ goto bad;
+ if (opt[off] & 0x20)
+ memset(&opt[off+2], 0, opt[off+1]);
+ break;
+ }
+
+ off += optlen;
+ len -= optlen;
+ }
+ if (len == 0)
+ return 1;
+
+bad:
+ return 0;
+}
+
+/**
+ * ipv6_rearrange_rthdr - rearrange IPv6 routing header
+ * @iph: IPv6 header
+ * @rthdr: routing header
+ *
+ * Rearrange the destination address in @iph and the addresses in @rthdr
+ * so that they appear in the order they will at the final destination.
+ * See Appendix A2 of RFC 2402 for details.
+ */
+static void ipv6_rearrange_rthdr(struct ipv6hdr *iph, struct ipv6_rt_hdr *rthdr)
+{
+ int segments, segments_left;
+ struct in6_addr *addrs;
+ struct in6_addr final_addr;
+
+ segments_left = rthdr->segments_left;
+ if (segments_left == 0)
+ return;
+ rthdr->segments_left = 0;
+
+ /* The value of rthdr->hdrlen has been verified either by the system
+ * call if it is locally generated, or by ipv6_rthdr_rcv() for incoming
+ * packets. So we can assume that it is even and that segments is
+ * greater than or equal to segments_left.
+ *
+ * For the same reason we can assume that this option is of type 0.
+ */
+ segments = rthdr->hdrlen >> 1;
+
+ addrs = ((struct rt0_hdr *)rthdr)->addr;
+ ipv6_addr_copy(&final_addr, addrs + segments - 1);
+
+ addrs += segments - segments_left;
+ memmove(addrs + 1, addrs, (segments_left - 1) * sizeof(*addrs));
+
+ ipv6_addr_copy(addrs, &iph->daddr);
+ ipv6_addr_copy(&iph->daddr, &final_addr);
+}
+
+static int ipv6_clear_mutable_options(struct ipv6hdr *iph, int len)
+{
+ union {
+ struct ipv6hdr *iph;
+ struct ipv6_opt_hdr *opth;
+ struct ipv6_rt_hdr *rth;
+ char *raw;
+ } exthdr = { .iph = iph };
+ char *end = exthdr.raw + len;
+ int nexthdr = iph->nexthdr;
+
+ exthdr.iph++;
+
+ while (exthdr.raw < end) {
+ switch (nexthdr) {
+ case NEXTHDR_HOP:
+ case NEXTHDR_DEST:
+ if (!zero_out_mutable_opts(exthdr.opth)) {
+ LIMIT_NETDEBUG(printk(
+ KERN_WARNING "overrun %sopts\n",
+ nexthdr == NEXTHDR_HOP ?
+ "hop" : "dest"));
+ return -EINVAL;
+ }
+ break;
+
+ case NEXTHDR_ROUTING:
+ ipv6_rearrange_rthdr(iph, exthdr.rth);
+ break;
+
+ default :
+ return 0;
+ }
+
+ nexthdr = exthdr.opth->nexthdr;
+ exthdr.raw += ipv6_optlen(exthdr.opth);
+ }
+
+ return 0;
+}
+
+static int ah6_output(struct xfrm_state *x, struct sk_buff *skb)
+{
+ int err;
+ int extlen;
+ struct ipv6hdr *top_iph;
+ struct ip_auth_hdr *ah;
+ struct ah_data *ahp;
+ u8 nexthdr;
+ char tmp_base[8];
+ struct {
+ struct in6_addr daddr;
+ char hdrs[0];
+ } *tmp_ext;
+
+ top_iph = (struct ipv6hdr *)skb->data;
+ top_iph->payload_len = htons(skb->len - sizeof(*top_iph));
+
+ nexthdr = *skb->nh.raw;
+ *skb->nh.raw = IPPROTO_AH;
+
+ /* When there are no extension headers, we only need to save the first
+ * 8 bytes of the base IP header.
+ */
+ memcpy(tmp_base, top_iph, sizeof(tmp_base));
+
+ tmp_ext = NULL;
+ extlen = skb->h.raw - (unsigned char *)(top_iph + 1);
+ if (extlen) {
+ extlen += sizeof(*tmp_ext);
+ tmp_ext = kmalloc(extlen, GFP_ATOMIC);
+ if (!tmp_ext) {
+ err = -ENOMEM;
+ goto error;
+ }
+ memcpy(tmp_ext, &top_iph->daddr, extlen);
+ err = ipv6_clear_mutable_options(top_iph,
+ extlen - sizeof(*tmp_ext) +
+ sizeof(*top_iph));
+ if (err)
+ goto error_free_iph;
+ }
+
+ ah = (struct ip_auth_hdr *)skb->h.raw;
+ ah->nexthdr = nexthdr;
+
+ top_iph->priority = 0;
+ top_iph->flow_lbl[0] = 0;
+ top_iph->flow_lbl[1] = 0;
+ top_iph->flow_lbl[2] = 0;
+ top_iph->hop_limit = 0;
+
+ ahp = x->data;
+ ah->hdrlen = (XFRM_ALIGN8(sizeof(struct ipv6_auth_hdr) +
+ ahp->icv_trunc_len) >> 2) - 2;
+
+ ah->reserved = 0;
+ ah->spi = x->id.spi;
+ ah->seq_no = htonl(++x->replay.oseq);
+ ahp->icv(ahp, skb, ah->auth_data);
+
+ err = 0;
+
+ memcpy(top_iph, tmp_base, sizeof(tmp_base));
+ if (tmp_ext) {
+ memcpy(&top_iph->daddr, tmp_ext, extlen);
+error_free_iph:
+ kfree(tmp_ext);
+ }
+
+error:
+ return err;
+}
+
+static int ah6_input(struct xfrm_state *x, struct xfrm_decap_state *decap, struct sk_buff *skb)
+{
+ /*
+ * Before process AH
+ * [IPv6][Ext1][Ext2][AH][Dest][Payload]
+ * |<-------------->| hdr_len
+ *
+ * To erase AH:
+ * Keeping copy of cleared headers. After AH processing,
+ * Moving the pointer of skb->nh.raw by using skb_pull as long as AH
+ * header length. Then copy back the copy as long as hdr_len
+ * If destination header following AH exists, copy it into after [Ext2].
+ *
+ * |<>|[IPv6][Ext1][Ext2][Dest][Payload]
+ * There is offset of AH before IPv6 header after the process.
+ */
+
+ struct ipv6_auth_hdr *ah;
+ struct ah_data *ahp;
+ unsigned char *tmp_hdr = NULL;
+ u16 hdr_len;
+ u16 ah_hlen;
+ int nexthdr;
+
+ if (!pskb_may_pull(skb, sizeof(struct ip_auth_hdr)))
+ goto out;
+
+ /* We are going to _remove_ AH header to keep sockets happy,
+ * so... Later this can change. */
+ if (skb_cloned(skb) &&
+ pskb_expand_head(skb, 0, 0, GFP_ATOMIC))
+ goto out;
+
+ hdr_len = skb->data - skb->nh.raw;
+ ah = (struct ipv6_auth_hdr*)skb->data;
+ ahp = x->data;
+ nexthdr = ah->nexthdr;
+ ah_hlen = (ah->hdrlen + 2) << 2;
+
+ if (ah_hlen != XFRM_ALIGN8(sizeof(struct ipv6_auth_hdr) + ahp->icv_full_len) &&
+ ah_hlen != XFRM_ALIGN8(sizeof(struct ipv6_auth_hdr) + ahp->icv_trunc_len))
+ goto out;
+
+ if (!pskb_may_pull(skb, ah_hlen))
+ goto out;
+
+ tmp_hdr = kmalloc(hdr_len, GFP_ATOMIC);
+ if (!tmp_hdr)
+ goto out;
+ memcpy(tmp_hdr, skb->nh.raw, hdr_len);
+ if (ipv6_clear_mutable_options(skb->nh.ipv6h, hdr_len))
+ goto out;
+ skb->nh.ipv6h->priority = 0;
+ skb->nh.ipv6h->flow_lbl[0] = 0;
+ skb->nh.ipv6h->flow_lbl[1] = 0;
+ skb->nh.ipv6h->flow_lbl[2] = 0;
+ skb->nh.ipv6h->hop_limit = 0;
+
+ {
+ u8 auth_data[MAX_AH_AUTH_LEN];
+
+ memcpy(auth_data, ah->auth_data, ahp->icv_trunc_len);
+ memset(ah->auth_data, 0, ahp->icv_trunc_len);
+ skb_push(skb, skb->data - skb->nh.raw);
+ ahp->icv(ahp, skb, ah->auth_data);
+ if (memcmp(ah->auth_data, auth_data, ahp->icv_trunc_len)) {
+ LIMIT_NETDEBUG(
+ printk(KERN_WARNING "ipsec ah authentication error\n"));
+ x->stats.integrity_failed++;
+ goto free_out;
+ }
+ }
+
+ skb->nh.raw = skb_pull(skb, ah_hlen);
+ memcpy(skb->nh.raw, tmp_hdr, hdr_len);
+ skb->nh.ipv6h->payload_len = htons(skb->len - sizeof(struct ipv6hdr));
+ skb_pull(skb, hdr_len);
+ skb->h.raw = skb->data;
+
+
+ kfree(tmp_hdr);
+
+ return nexthdr;
+
+free_out:
+ kfree(tmp_hdr);
+out:
+ return -EINVAL;
+}
+
+static void ah6_err(struct sk_buff *skb, struct inet6_skb_parm *opt,
+ int type, int code, int offset, __u32 info)
+{
+ struct ipv6hdr *iph = (struct ipv6hdr*)skb->data;
+ struct ip_auth_hdr *ah = (struct ip_auth_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, ah->spi, IPPROTO_AH, AF_INET6);
+ if (!x)
+ return;
+
+ NETDEBUG(printk(KERN_DEBUG "pmtu discovery on SA AH/%08x/"
+ "%04x:%04x:%04x:%04x:%04x:%04x:%04x:%04x\n",
+ ntohl(ah->spi), NIP6(iph->daddr)));
+
+ xfrm_state_put(x);
+}
+
+static int ah6_init_state(struct xfrm_state *x, void *args)
+{
+ struct ah_data *ahp = NULL;
+ struct xfrm_algo_desc *aalg_desc;
+
+ if (!x->aalg)
+ goto error;
+
+ /* null auth can use a zero length key */
+ if (x->aalg->alg_key_len > 512)
+ goto error;
+
+ if (x->encap)
+ goto error;
+
+ ahp = kmalloc(sizeof(*ahp), GFP_KERNEL);
+ if (ahp == NULL)
+ return -ENOMEM;
+
+ memset(ahp, 0, sizeof(*ahp));
+
+ ahp->key = x->aalg->alg_key;
+ ahp->key_len = (x->aalg->alg_key_len+7)/8;
+ ahp->tfm = crypto_alloc_tfm(x->aalg->alg_name, 0);
+ if (!ahp->tfm)
+ goto error;
+ ahp->icv = ah_hmac_digest;
+
+ /*
+ * Lookup the algorithm description maintained by xfrm_algo,
+ * verify crypto transform properties, and store information
+ * we need for AH processing. This lookup cannot fail here
+ * after a successful crypto_alloc_tfm().
+ */
+ aalg_desc = xfrm_aalg_get_byname(x->aalg->alg_name, 0);
+ BUG_ON(!aalg_desc);
+
+ if (aalg_desc->uinfo.auth.icv_fullbits/8 !=
+ crypto_tfm_alg_digestsize(ahp->tfm)) {
+ printk(KERN_INFO "AH: %s digestsize %u != %hu\n",
+ x->aalg->alg_name, crypto_tfm_alg_digestsize(ahp->tfm),
+ aalg_desc->uinfo.auth.icv_fullbits/8);
+ goto error;
+ }
+
+ ahp->icv_full_len = aalg_desc->uinfo.auth.icv_fullbits/8;
+ ahp->icv_trunc_len = aalg_desc->uinfo.auth.icv_truncbits/8;
+
+ BUG_ON(ahp->icv_trunc_len > MAX_AH_AUTH_LEN);
+
+ ahp->work_icv = kmalloc(ahp->icv_full_len, GFP_KERNEL);
+ if (!ahp->work_icv)
+ goto error;
+
+ x->props.header_len = XFRM_ALIGN8(sizeof(struct ipv6_auth_hdr) + ahp->icv_trunc_len);
+ if (x->props.mode)
+ x->props.header_len += sizeof(struct ipv6hdr);
+ x->data = ahp;
+
+ return 0;
+
+error:
+ if (ahp) {
+ if (ahp->work_icv)
+ kfree(ahp->work_icv);
+ if (ahp->tfm)
+ crypto_free_tfm(ahp->tfm);
+ kfree(ahp);
+ }
+ return -EINVAL;
+}
+
+static void ah6_destroy(struct xfrm_state *x)
+{
+ struct ah_data *ahp = x->data;
+
+ if (!ahp)
+ return;
+
+ if (ahp->work_icv) {
+ kfree(ahp->work_icv);
+ ahp->work_icv = NULL;
+ }
+ if (ahp->tfm) {
+ crypto_free_tfm(ahp->tfm);
+ ahp->tfm = NULL;
+ }
+ kfree(ahp);
+}
+
+static struct xfrm_type ah6_type =
+{
+ .description = "AH6",
+ .owner = THIS_MODULE,
+ .proto = IPPROTO_AH,
+ .init_state = ah6_init_state,
+ .destructor = ah6_destroy,
+ .input = ah6_input,
+ .output = ah6_output
+};
+
+static struct inet6_protocol ah6_protocol = {
+ .handler = xfrm6_rcv,
+ .err_handler = ah6_err,
+ .flags = INET6_PROTO_NOPOLICY,
+};
+
+static int __init ah6_init(void)
+{
+ if (xfrm_register_type(&ah6_type, AF_INET6) < 0) {
+ printk(KERN_INFO "ipv6 ah init: can't add xfrm type\n");
+ return -EAGAIN;
+ }
+
+ if (inet6_add_protocol(&ah6_protocol, IPPROTO_AH) < 0) {
+ printk(KERN_INFO "ipv6 ah init: can't add protocol\n");
+ xfrm_unregister_type(&ah6_type, AF_INET6);
+ return -EAGAIN;
+ }
+
+ return 0;
+}
+
+static void __exit ah6_fini(void)
+{
+ if (inet6_del_protocol(&ah6_protocol, IPPROTO_AH) < 0)
+ printk(KERN_INFO "ipv6 ah close: can't remove protocol\n");
+
+ if (xfrm_unregister_type(&ah6_type, AF_INET6) < 0)
+ printk(KERN_INFO "ipv6 ah close: can't remove xfrm type\n");
+
+}
+
+module_init(ah6_init);
+module_exit(ah6_fini);
+
+MODULE_LICENSE("GPL");
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