net/tls: avoid NULL pointer deref on nskb->sk in fallback

update_chksum() accesses nskb->sk before it has been set
by complete_skb(), move the init up.

Fixes: e8f69799810c ("net/tls: Add generic NIC offload infrastructure")
Signed-off-by: Jakub Kicinski <jakub.kicinski@netronome.com>
Reviewed-by: Simon Horman <simon.horman@netronome.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 2 insertions, 1 deletions

diff --git a/net/tls/tls_device_fallback.c b/net/tls/tls_device_fallback.c
index a3ebd4b02714..c3a5fe624b4e 100644
--- a/net/tls/tls_device_fallback.c
+++ b/net/tls/tls_device_fallback.c
@@ -201,13 +201,14 @@ static void complete_skb(struct sk_buff *nskb, struct sk_buff *skb, int headln)
 
         skb_put(nskb, skb->len);
         memcpy(nskb->data, skb->data, headln);
-        update_chksum(nskb, headln);
 
         nskb->destructor = skb->destructor;
         nskb->sk = sk;
         skb->destructor = NULL;
         skb->sk = NULL;
 
+        update_chksum(nskb, headln);
+
         delta = nskb->truesize - skb->truesize;
         if (likely(delta < 0))
                 WARN_ON_ONCE(refcount_sub_and_test(-delta, &sk->sk_wmem_alloc));