2006-08-20 06:24:50 +02:00
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#include <linux/err.h>
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2005-04-17 00:20:36 +02:00
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#include <linux/module.h>
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#include <net/ip.h>
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#include <net/xfrm.h>
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#include <net/ah.h>
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#include <linux/crypto.h>
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#include <linux/pfkeyv2.h>
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2007-10-09 22:33:35 +02:00
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#include <linux/spinlock.h>
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2005-04-17 00:20:36 +02:00
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#include <net/icmp.h>
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2005-12-27 05:43:12 +01:00
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#include <net/protocol.h>
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2005-04-17 00:20:36 +02:00
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#include <asm/scatterlist.h>
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/* Clear mutable options and find final destination to substitute
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* into IP header for icv calculation. Options are already checked
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* for validity, so paranoia is not required. */
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2006-11-08 09:23:14 +01:00
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static int ip_clear_mutable_options(struct iphdr *iph, __be32 *daddr)
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2005-04-17 00:20:36 +02:00
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{
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unsigned char * optptr = (unsigned char*)(iph+1);
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int l = iph->ihl*4 - sizeof(struct iphdr);
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int optlen;
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while (l > 0) {
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switch (*optptr) {
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case IPOPT_END:
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return 0;
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case IPOPT_NOOP:
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l--;
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optptr++;
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continue;
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}
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optlen = optptr[1];
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if (optlen<2 || optlen>l)
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return -EINVAL;
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switch (*optptr) {
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case IPOPT_SEC:
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case 0x85: /* Some "Extended Security" crap. */
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2006-08-04 01:46:20 +02:00
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case IPOPT_CIPSO:
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2005-04-17 00:20:36 +02:00
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case IPOPT_RA:
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case 0x80|21: /* RFC1770 */
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break;
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case IPOPT_LSRR:
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case IPOPT_SSRR:
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if (optlen < 6)
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return -EINVAL;
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memcpy(daddr, optptr+optlen-4, 4);
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/* Fall through */
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default:
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[IPSEC] AH4: Update IPv4 options handling to conform to RFC 4302.
In testing our ESP/AH offload hardware, I discovered an issue with how
AH handles mutable fields in IPv4. RFC 4302 (AH) states the following
on the subject:
For IPv4, the entire option is viewed as a unit; so even
though the type and length fields within most options are immutable
in transit, if an option is classified as mutable, the entire option
is zeroed for ICV computation purposes.
The current implementation does not zero the type and length fields,
resulting in authentication failures when communicating with hosts
that do (i.e. FreeBSD).
I have tested record route and timestamp options (ping -R and ping -T)
on a small network involving Windows XP, FreeBSD 6.2, and Linux hosts,
with one router. In the presence of these options, the FreeBSD and
Linux hosts (with the patch or with the hardware) can communicate.
The Windows XP host simply fails to accept these packets with or
without the patch.
I have also been trying to test source routing options (using
traceroute -g), but haven't had much luck getting this option to work
*without* AH, let alone with.
Signed-off-by: Nick Bowler <nbowler@ellipticsemi.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2007-08-22 21:33:51 +02:00
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memset(optptr, 0, optlen);
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2005-04-17 00:20:36 +02:00
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}
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l -= optlen;
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optptr += optlen;
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}
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return 0;
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}
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static int ah_output(struct xfrm_state *x, struct sk_buff *skb)
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{
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int err;
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struct iphdr *iph, *top_iph;
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struct ip_auth_hdr *ah;
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struct ah_data *ahp;
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union {
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struct iphdr iph;
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char buf[60];
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} tmp_iph;
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2007-10-11 00:44:06 +02:00
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skb_push(skb, -skb_network_offset(skb));
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2007-04-21 07:47:35 +02:00
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top_iph = ip_hdr(skb);
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2005-04-17 00:20:36 +02:00
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iph = &tmp_iph.iph;
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iph->tos = top_iph->tos;
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iph->ttl = top_iph->ttl;
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iph->frag_off = top_iph->frag_off;
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if (top_iph->ihl != 5) {
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iph->daddr = top_iph->daddr;
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memcpy(iph+1, top_iph+1, top_iph->ihl*4 - sizeof(struct iphdr));
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err = ip_clear_mutable_options(top_iph, &top_iph->daddr);
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if (err)
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goto error;
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}
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2007-10-11 00:45:25 +02:00
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ah = ip_auth_hdr(skb);
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2007-10-11 00:44:44 +02:00
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ah->nexthdr = *skb_mac_header(skb);
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*skb_mac_header(skb) = IPPROTO_AH;
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2005-04-17 00:20:36 +02:00
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top_iph->tos = 0;
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top_iph->tot_len = htons(skb->len);
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top_iph->frag_off = 0;
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top_iph->ttl = 0;
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top_iph->check = 0;
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ahp = x->data;
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2007-10-11 00:45:25 +02:00
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ah->hdrlen = (XFRM_ALIGN8(sizeof(*ah) + ahp->icv_trunc_len) >> 2) - 2;
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2005-04-17 00:20:36 +02:00
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ah->reserved = 0;
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ah->spi = x->id.spi;
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2007-10-09 02:25:53 +02:00
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ah->seq_no = htonl(XFRM_SKB_CB(skb)->seq);
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2007-10-09 22:33:35 +02:00
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spin_lock_bh(&x->lock);
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2006-08-20 06:24:50 +02:00
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err = ah_mac_digest(ahp, skb, ah->auth_data);
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2007-10-09 22:33:35 +02:00
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memcpy(ah->auth_data, ahp->work_icv, ahp->icv_trunc_len);
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spin_unlock_bh(&x->lock);
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2006-08-20 06:24:50 +02:00
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if (err)
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goto error;
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2005-04-17 00:20:36 +02:00
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top_iph->tos = iph->tos;
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top_iph->ttl = iph->ttl;
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top_iph->frag_off = iph->frag_off;
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if (top_iph->ihl != 5) {
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top_iph->daddr = iph->daddr;
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memcpy(top_iph+1, iph+1, top_iph->ihl*4 - sizeof(struct iphdr));
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}
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err = 0;
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error:
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return err;
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}
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2006-04-01 10:52:46 +02:00
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static int ah_input(struct xfrm_state *x, struct sk_buff *skb)
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2005-04-17 00:20:36 +02:00
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{
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int ah_hlen;
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2006-05-28 08:06:13 +02:00
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int ihl;
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2006-08-20 06:24:50 +02:00
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int err = -EINVAL;
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2005-04-17 00:20:36 +02:00
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struct iphdr *iph;
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struct ip_auth_hdr *ah;
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struct ah_data *ahp;
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char work_buf[60];
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2007-10-11 00:45:25 +02:00
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if (!pskb_may_pull(skb, sizeof(*ah)))
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2005-04-17 00:20:36 +02:00
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goto out;
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2007-10-11 00:45:25 +02:00
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ah = (struct ip_auth_hdr *)skb->data;
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2005-04-17 00:20:36 +02:00
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ahp = x->data;
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ah_hlen = (ah->hdrlen + 2) << 2;
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2007-02-09 15:24:47 +01:00
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2007-10-11 00:45:25 +02:00
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if (ah_hlen != XFRM_ALIGN8(sizeof(*ah) + ahp->icv_full_len) &&
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ah_hlen != XFRM_ALIGN8(sizeof(*ah) + ahp->icv_trunc_len))
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2005-04-17 00:20:36 +02:00
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goto out;
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if (!pskb_may_pull(skb, ah_hlen))
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goto out;
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/* We are going to _remove_ AH header to keep sockets happy,
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* so... Later this can change. */
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if (skb_cloned(skb) &&
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pskb_expand_head(skb, 0, 0, GFP_ATOMIC))
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goto out;
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skb->ip_summed = CHECKSUM_NONE;
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2007-10-11 00:45:25 +02:00
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ah = (struct ip_auth_hdr *)skb->data;
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2007-04-21 07:47:35 +02:00
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iph = ip_hdr(skb);
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2005-04-17 00:20:36 +02:00
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2007-04-11 05:50:43 +02:00
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ihl = skb->data - skb_network_header(skb);
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2006-05-28 08:06:13 +02:00
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memcpy(work_buf, iph, ihl);
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2005-04-17 00:20:36 +02:00
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iph->ttl = 0;
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iph->tos = 0;
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iph->frag_off = 0;
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iph->check = 0;
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2006-05-28 08:06:13 +02:00
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if (ihl > sizeof(*iph)) {
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2006-11-08 09:23:14 +01:00
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__be32 dummy;
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2005-04-17 00:20:36 +02:00
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if (ip_clear_mutable_options(iph, &dummy))
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goto out;
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}
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2007-02-09 15:24:47 +01:00
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{
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2005-04-17 00:20:36 +02:00
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u8 auth_data[MAX_AH_AUTH_LEN];
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2007-02-09 15:24:47 +01:00
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2005-04-17 00:20:36 +02:00
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memcpy(auth_data, ah->auth_data, ahp->icv_trunc_len);
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2006-05-28 08:06:13 +02:00
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skb_push(skb, ihl);
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2006-08-20 06:24:50 +02:00
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err = ah_mac_digest(ahp, skb, ah->auth_data);
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if (err)
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goto out;
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err = -EINVAL;
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if (memcmp(ahp->work_icv, auth_data, ahp->icv_trunc_len)) {
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2005-04-17 00:20:36 +02:00
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x->stats.integrity_failed++;
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goto out;
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}
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}
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((struct iphdr*)work_buf)->protocol = ah->nexthdr;
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2007-04-11 06:21:55 +02:00
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skb->network_header += ah_hlen;
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2007-03-13 17:06:52 +01:00
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memcpy(skb_network_header(skb), work_buf, ihl);
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2007-04-11 06:21:55 +02:00
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skb->transport_header = skb->network_header;
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2006-05-28 08:06:13 +02:00
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__skb_pull(skb, ah_hlen + ihl);
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2005-04-17 00:20:36 +02:00
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return 0;
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out:
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2006-08-20 06:24:50 +02:00
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return err;
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2005-04-17 00:20:36 +02:00
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}
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static void ah4_err(struct sk_buff *skb, u32 info)
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{
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struct iphdr *iph = (struct iphdr*)skb->data;
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struct ip_auth_hdr *ah = (struct ip_auth_hdr*)(skb->data+(iph->ihl<<2));
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struct xfrm_state *x;
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2007-03-13 18:43:18 +01:00
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if (icmp_hdr(skb)->type != ICMP_DEST_UNREACH ||
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icmp_hdr(skb)->code != ICMP_FRAG_NEEDED)
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2005-04-17 00:20:36 +02:00
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return;
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x = xfrm_state_lookup((xfrm_address_t *)&iph->daddr, ah->spi, IPPROTO_AH, AF_INET);
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if (!x)
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return;
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printk(KERN_DEBUG "pmtu discovery on SA AH/%08x/%08x\n",
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ntohl(ah->spi), ntohl(iph->daddr));
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xfrm_state_put(x);
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}
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2005-06-20 22:18:08 +02:00
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static int ah_init_state(struct xfrm_state *x)
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2005-04-17 00:20:36 +02:00
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{
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struct ah_data *ahp = NULL;
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struct xfrm_algo_desc *aalg_desc;
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2006-08-20 06:24:50 +02:00
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struct crypto_hash *tfm;
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2005-04-17 00:20:36 +02:00
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if (!x->aalg)
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goto error;
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if (x->encap)
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goto error;
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2006-07-21 23:51:30 +02:00
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ahp = kzalloc(sizeof(*ahp), GFP_KERNEL);
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2005-04-17 00:20:36 +02:00
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if (ahp == NULL)
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return -ENOMEM;
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2006-08-20 06:24:50 +02:00
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tfm = crypto_alloc_hash(x->aalg->alg_name, 0, CRYPTO_ALG_ASYNC);
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if (IS_ERR(tfm))
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goto error;
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ahp->tfm = tfm;
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2007-10-09 02:14:34 +02:00
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if (crypto_hash_setkey(tfm, x->aalg->alg_key,
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(x->aalg->alg_key_len + 7) / 8))
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2005-04-17 00:20:36 +02:00
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goto error;
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2007-02-09 15:24:47 +01:00
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2005-04-17 00:20:36 +02:00
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/*
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* Lookup the algorithm description maintained by xfrm_algo,
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* verify crypto transform properties, and store information
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* we need for AH processing. This lookup cannot fail here
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2006-08-20 06:24:50 +02:00
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* after a successful crypto_alloc_hash().
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2005-04-17 00:20:36 +02:00
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*/
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aalg_desc = xfrm_aalg_get_byname(x->aalg->alg_name, 0);
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BUG_ON(!aalg_desc);
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if (aalg_desc->uinfo.auth.icv_fullbits/8 !=
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2006-08-20 06:24:50 +02:00
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crypto_hash_digestsize(tfm)) {
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2005-04-17 00:20:36 +02:00
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printk(KERN_INFO "AH: %s digestsize %u != %hu\n",
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2006-08-20 06:24:50 +02:00
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x->aalg->alg_name, crypto_hash_digestsize(tfm),
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2005-04-17 00:20:36 +02:00
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aalg_desc->uinfo.auth.icv_fullbits/8);
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goto error;
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}
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2007-02-09 15:24:47 +01:00
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2005-04-17 00:20:36 +02:00
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ahp->icv_full_len = aalg_desc->uinfo.auth.icv_fullbits/8;
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ahp->icv_trunc_len = aalg_desc->uinfo.auth.icv_truncbits/8;
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2007-02-09 15:24:47 +01:00
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2005-04-17 00:20:36 +02:00
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BUG_ON(ahp->icv_trunc_len > MAX_AH_AUTH_LEN);
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2007-02-09 15:24:47 +01:00
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2005-04-17 00:20:36 +02:00
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ahp->work_icv = kmalloc(ahp->icv_full_len, GFP_KERNEL);
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if (!ahp->work_icv)
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goto error;
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2007-02-09 15:24:47 +01:00
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2007-10-11 00:45:25 +02:00
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x->props.header_len = XFRM_ALIGN8(sizeof(struct ip_auth_hdr) +
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ahp->icv_trunc_len);
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2006-09-23 00:05:15 +02:00
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if (x->props.mode == XFRM_MODE_TUNNEL)
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2005-04-17 00:20:36 +02:00
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x->props.header_len += sizeof(struct iphdr);
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x->data = ahp;
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return 0;
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error:
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if (ahp) {
|
2005-09-02 02:44:29 +02:00
|
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kfree(ahp->work_icv);
|
2006-08-20 06:24:50 +02:00
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crypto_free_hash(ahp->tfm);
|
2005-04-17 00:20:36 +02:00
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kfree(ahp);
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}
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return -EINVAL;
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}
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static void ah_destroy(struct xfrm_state *x)
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|
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{
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struct ah_data *ahp = x->data;
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if (!ahp)
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return;
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|
|
2005-09-02 02:44:29 +02:00
|
|
|
kfree(ahp->work_icv);
|
|
|
|
ahp->work_icv = NULL;
|
2006-08-20 06:24:50 +02:00
|
|
|
crypto_free_hash(ahp->tfm);
|
2005-09-02 02:44:29 +02:00
|
|
|
ahp->tfm = NULL;
|
2005-04-17 00:20:36 +02:00
|
|
|
kfree(ahp);
|
|
|
|
}
|
|
|
|
|
|
|
|
|
|
|
|
static struct xfrm_type ah_type =
|
|
|
|
{
|
|
|
|
.description = "AH4",
|
|
|
|
.owner = THIS_MODULE,
|
|
|
|
.proto = IPPROTO_AH,
|
2007-10-09 02:25:53 +02:00
|
|
|
.flags = XFRM_TYPE_REPLAY_PROT,
|
2005-04-17 00:20:36 +02:00
|
|
|
.init_state = ah_init_state,
|
|
|
|
.destructor = ah_destroy,
|
|
|
|
.input = ah_input,
|
|
|
|
.output = ah_output
|
|
|
|
};
|
|
|
|
|
|
|
|
static struct net_protocol ah4_protocol = {
|
|
|
|
.handler = xfrm4_rcv,
|
|
|
|
.err_handler = ah4_err,
|
|
|
|
.no_policy = 1,
|
|
|
|
};
|
|
|
|
|
|
|
|
static int __init ah4_init(void)
|
|
|
|
{
|
|
|
|
if (xfrm_register_type(&ah_type, AF_INET) < 0) {
|
|
|
|
printk(KERN_INFO "ip ah init: can't add xfrm type\n");
|
|
|
|
return -EAGAIN;
|
|
|
|
}
|
|
|
|
if (inet_add_protocol(&ah4_protocol, IPPROTO_AH) < 0) {
|
|
|
|
printk(KERN_INFO "ip ah init: can't add protocol\n");
|
|
|
|
xfrm_unregister_type(&ah_type, AF_INET);
|
|
|
|
return -EAGAIN;
|
|
|
|
}
|
|
|
|
return 0;
|
|
|
|
}
|
|
|
|
|
|
|
|
static void __exit ah4_fini(void)
|
|
|
|
{
|
|
|
|
if (inet_del_protocol(&ah4_protocol, IPPROTO_AH) < 0)
|
|
|
|
printk(KERN_INFO "ip ah close: can't remove protocol\n");
|
|
|
|
if (xfrm_unregister_type(&ah_type, AF_INET) < 0)
|
|
|
|
printk(KERN_INFO "ip ah close: can't remove xfrm type\n");
|
|
|
|
}
|
|
|
|
|
|
|
|
module_init(ah4_init);
|
|
|
|
module_exit(ah4_fini);
|
|
|
|
MODULE_LICENSE("GPL");
|
2007-06-27 08:57:49 +02:00
|
|
|
MODULE_ALIAS_XFRM_TYPE(AF_INET, XFRM_PROTO_AH);
|