[ESP]: Ensure IV is in linear part of the skb to avoid BUG() due to O…

…OB access ESP does not account for the IV size when calling pskb_may_pull() to ensure everything it accesses directly is within the linear part of a potential fragment. This results in a BUG() being triggered when the both the IPv4 and IPv6 ESP stack is fed with an skb where the first fragment ends between the end of the esp header and the end of the IV. This bug was found by Dirk Nehring <[email protected]> . Signed-off-by: Thomas Graf <[email protected]> Signed-off-by: David S. Miller <[email protected]>
chewitt · Mar 27, 2008 · 920fc94 · 920fc94
1 parent 732c8bd
commit 920fc94
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Showing 2 changed files with 2 additions and 2 deletions.
diff --git a/net/ipv4/esp4.c b/net/ipv4/esp4.c
@@ -336,7 +336,7 @@ static int esp_input(struct xfrm_state *x, struct sk_buff *skb)
 	struct scatterlist *asg;
 	int err = -EINVAL;
 
-	if (!pskb_may_pull(skb, sizeof(*esph)))
+	if (!pskb_may_pull(skb, sizeof(*esph) + crypto_aead_ivsize(aead)))
 		goto out;
 
 	if (elen <= 0)

diff --git a/net/ipv6/esp6.c b/net/ipv6/esp6.c
@@ -282,7 +282,7 @@ static int esp6_input(struct xfrm_state *x, struct sk_buff *skb)
 	struct scatterlist *sg;
 	struct scatterlist *asg;
 
-	if (!pskb_may_pull(skb, sizeof(*esph))) {
+	if (!pskb_may_pull(skb, sizeof(*esph) + crypto_aead_ivsize(aead))) {
 		ret = -EINVAL;
 		goto out;
 	}