sock: fix possible NULL sk dereference in __skb_tstamp_tx
Test that sk != NULL before reading sk->sk_tsflags.
Fixes: 49ca0d8bfaf3 ("net-timestamp: no-payload option")
Reported-by: One Thousand Gnomes <gnomes@lxorguk.ukuu.org.uk>
Signed-off-by: Willem de Bruijn <willemb@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/core/skbuff.c b/net/core/skbuff.c
index 434e78e..8e4ac97 100644
--- a/net/core/skbuff.c
+++ b/net/core/skbuff.c
@@ -3733,9 +3733,13 @@
struct sock *sk, int tstype)
{
struct sk_buff *skb;
- bool tsonly = sk->sk_tsflags & SOF_TIMESTAMPING_OPT_TSONLY;
+ bool tsonly;
- if (!sk || !skb_may_tx_timestamp(sk, tsonly))
+ if (!sk)
+ return;
+
+ tsonly = sk->sk_tsflags & SOF_TIMESTAMPING_OPT_TSONLY;
+ if (!skb_may_tx_timestamp(sk, tsonly))
return;
if (tsonly)