[IPCOMP]: Fetch nexthdr before ipch is destroyed

When I moved the nexthdr setting out of IPComp I accidently moved
the reading of ipch->nexthdr after the decompression.  Unfortunately
this means that we'd be reading from a stale ipch pointer which
doesn't work very well.

This patch moves the reading up so that we get the correct nexthdr
value.

Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: David S. Miller <davem@davemloft.net>

2 files changed, 8 insertions, 2 deletions

diff --git a/net/ipv4/ipcomp.c b/net/ipv4/ipcomp.c
index f4af99ad8fdb..b79cdbee68a9 100644
--- a/net/ipv4/ipcomp.c
+++ b/net/ipv4/ipcomp.c
@@ -74,6 +74,7 @@ out:
 
 static int ipcomp_input(struct xfrm_state *x, struct sk_buff *skb)
 {
+        int nexthdr;
         int err = -ENOMEM;
         struct ip_comp_hdr *ipch;
 
@@ -84,13 +85,15 @@ static int ipcomp_input(struct xfrm_state *x, struct sk_buff *skb)
 
         /* Remove ipcomp header and decompress original payload */
         ipch = (void *)skb->data;
+        nexthdr = ipch->nexthdr;
+
         skb->transport_header = skb->network_header + sizeof(*ipch);
         __skb_pull(skb, sizeof(*ipch));
         err = ipcomp_decompress(x, skb);
         if (err)
                 goto out;
 
-        err = ipch->nexthdr;
+        err = nexthdr;
 
 out:
         return err;
diff --git a/net/ipv6/ipcomp6.c b/net/ipv6/ipcomp6.c
index b276d04d6db5..710325e7a842 100644
--- a/net/ipv6/ipcomp6.c
+++ b/net/ipv6/ipcomp6.c
@@ -64,6 +64,7 @@ static LIST_HEAD(ipcomp6_tfms_list);
 
 static int ipcomp6_input(struct xfrm_state *x, struct sk_buff *skb)
 {
+        int nexthdr;
         int err = -ENOMEM;
         struct ip_comp_hdr *ipch;
         int plen, dlen;
@@ -79,6 +80,8 @@ static int ipcomp6_input(struct xfrm_state *x, struct sk_buff *skb)
 
         /* Remove ipcomp header and decompress original payload */
         ipch = (void *)skb->data;
+        nexthdr = ipch->nexthdr;
+
         skb->transport_header = skb->network_header + sizeof(*ipch);
         __skb_pull(skb, sizeof(*ipch));
 
@@ -108,7 +111,7 @@ static int ipcomp6_input(struct xfrm_state *x, struct sk_buff *skb)
         skb->truesize += dlen - plen;
         __skb_put(skb, dlen - plen);
         skb_copy_to_linear_data(skb, scratch, dlen);
-        err = ipch->nexthdr;
+        err = nexthdr;
 
 out_put_cpu:
         put_cpu();