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From:   Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To:     linux-kernel@vger.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        stable@vger.kernel.org,
        Jakub Kicinski <jakub.kicinski@netronome.com>,
        Simon Horman <simon.horman@netronome.com>,
        "David S. Miller" <davem@davemloft.net>
Subject: [PATCH 4.19 10/23] net/tls: avoid NULL pointer deref on nskb->sk in fallback
Date:   Sat,  4 May 2019 12:25:12 +0200
Message-Id: <20190504102451.887482769@linuxfoundation.org>
In-Reply-To: <20190504102451.512405835@linuxfoundation.org>
References: <20190504102451.512405835@linuxfoundation.org>
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From: Jakub Kicinski <jakub.kicinski@netronome.com>

[ Upstream commit 2dcb003314032c6efb13a065ffae60d164b2dd35 ]

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>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
 net/tls/tls_device_fallback.c |    3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

--- a/net/tls/tls_device_fallback.c
+++ b/net/tls/tls_device_fallback.c
@@ -200,13 +200,14 @@ static void complete_skb(struct sk_buff
 
 	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));