{IPv4,xfrm} Add ESN support for AH ingress part

This patch add esn support for AH input stage by attaching upper 32bits sequence number right after packet payload as specified by RFC 4302. Then the ICV value will guard upper 32bits sequence number as well when packet getting in. Signed-off-by: Fan Du <[email protected]> Signed-off-by: Steffen Klassert <[email protected]>
Baughn · Feb 12, 2014 · d8b2a86 · d8b2a86
1 parent d4d573d
commit d8b2a86
Showing 1 changed file with 22 additions and 5 deletions.
diff --git a/net/ipv4/ah4.c b/net/ipv4/ah4.c
@@ -309,6 +309,10 @@ static int ah_input(struct xfrm_state *x, struct sk_buff *skb)
 	struct ip_auth_hdr *ah;
 	struct ah_data *ahp;
 	int err = -ENOMEM;
+	int seqhi_len = 0;
+	__be32 *seqhi;
+	int sglists = 0;
+	struct scatterlist *seqhisg;
 
 	if (!pskb_may_pull(skb, sizeof(*ah)))
 		goto out;
@@ -349,14 +353,22 @@ static int ah_input(struct xfrm_state *x, struct sk_buff *skb)
 	iph = ip_hdr(skb);
 	ihl = ip_hdrlen(skb);
 
-	work_iph = ah_alloc_tmp(ahash, nfrags, ihl + ahp->icv_trunc_len);
+	if (x->props.flags & XFRM_STATE_ESN) {
+		sglists = 1;
+		seqhi_len = sizeof(*seqhi);
+	}
+
+	work_iph = ah_alloc_tmp(ahash, nfrags + sglists, ihl +
+				ahp->icv_trunc_len + seqhi_len);
 	if (!work_iph)
 		goto out;
 
-	auth_data = ah_tmp_auth(work_iph, ihl);
+	seqhi = (__be32 *)((char *)work_iph + ihl);
+	auth_data = ah_tmp_auth(seqhi, seqhi_len);
 	icv = ah_tmp_icv(ahash, auth_data, ahp->icv_trunc_len);
 	req = ah_tmp_req(ahash, icv);
 	sg = ah_req_sg(ahash, req);
+	seqhisg = sg + nfrags;
 
 	memcpy(work_iph, iph, ihl);
 	memcpy(auth_data, ah->auth_data, ahp->icv_trunc_len);
@@ -375,10 +387,15 @@ static int ah_input(struct xfrm_state *x, struct sk_buff *skb)
 
 	skb_push(skb, ihl);
 
-	sg_init_table(sg, nfrags);
-	skb_to_sgvec(skb, sg, 0, skb->len);
+	sg_init_table(sg, nfrags + sglists);
+	skb_to_sgvec_nomark(skb, sg, 0, skb->len);
 
-	ahash_request_set_crypt(req, sg, icv, skb->len);
+	if (x->props.flags & XFRM_STATE_ESN) {
+		/* Attach seqhi sg right after packet payload */
+		*seqhi = XFRM_SKB_CB(skb)->seq.input.hi;
+		sg_set_buf(seqhisg, seqhi, seqhi_len);
+	}
+	ahash_request_set_crypt(req, sg, icv, skb->len + seqhi_len);
 	ahash_request_set_callback(req, 0, ah_input_done, skb);
 
 	AH_SKB_CB(skb)->tmp = work_iph;