net: dsa: ksz: Check return value

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

Found by Linux Verification Center (linuxtesting.org) with SVACE.

Fixes: bafe9ba7d908 ("net: dsa: ksz: Factor out common tag code")
Signed-off-by: Artem Chernyshev <artem.chernyshev@red-soft.ru>
Reviewed-by: Vladimir Oltean <olteanv@gmail.com>
Reviewed-by: Florian Fainelli <f.fainelli@gmail.com>
Link: https://lore.kernel.org/r/20221201140032.26746-1-artem.chernyshev@red-soft.ru
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

diff --git a/net/dsa/tag_ksz.c b/net/dsa/tag_ksz.c
index 38fa19c..4292502 100644 (file)
--- a/net/dsa/tag_ksz.c
+++ b/net/dsa/tag_ksz.c
@@ -21,7 +21,8 @@ static struct sk_buff *ksz_common_rcv(struct sk_buff *skb,
        if (!skb->dev)
                return NULL;
 
-       pskb_trim_rcsum(skb, skb->len - len);
+       if (pskb_trim_rcsum(skb, skb->len - len))
+               return NULL;
 
        dsa_default_offload_fwd_mark(skb);