net: dsa: hellcreek: Check return value

[ Upstream commit d4edb50688652eb10be270bc515da63815de428f ]

Return NULL if we got unexpected value from skb_trim_rcsum()
in hellcreek_rcv()

Fixes: 01ef09caad66 ("net: dsa: Add tag handling for Hirschmann Hellcreek switches")
Signed-off-by: Artem Chernyshev <artem.chernyshev@red-soft.ru>
Reviewed-by: Florian Fainelli <f.fainelli@gmail.com>
Reviewed-by: Kurt Kanzenbach <kurt@linutronix.de>
Link: https://lore.kernel.org/r/20221201140032.26746-2-artem.chernyshev@red-soft.ru
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>

diff --git a/net/dsa/tag_hellcreek.c b/net/dsa/tag_hellcreek.c
index 846588c0070a5e2a43afee4a1bb553203643d51f..53a206d116850b2748b2f6df7ba416be64d7ec40 100644 (file)
--- a/net/dsa/tag_hellcreek.c
+++ b/net/dsa/tag_hellcreek.c
@@ -49,7 +49,8 @@ static struct sk_buff *hellcreek_rcv(struct sk_buff *skb,
                return NULL;
        }
 
-       pskb_trim_rcsum(skb, skb->len - HELLCREEK_TAG_LEN);
+       if (pskb_trim_rcsum(skb, skb->len - HELLCREEK_TAG_LEN))
+               return NULL;
 
        dsa_default_offload_fwd_mark(skb);