net: dsa: sja1105: Check return value

Return NULL if we got unexpected value from skb_trim_rcsum() in
sja1110_rcv_inband_control_extension()

Fixes: 4913b8ebf8a9 ("net: dsa: add support for the SJA1110 native tagging protocol")
Signed-off-by: Artem Chernyshev <artem.chernyshev@red-soft.ru>
Reviewed-by: Florian Fainelli <f.fainelli@gmail.com>
Link: https://lore.kernel.org/r/20221201140032.26746-3-artem.chernyshev@red-soft.ru
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

diff --git a/net/dsa/tag_sja1105.c b/net/dsa/tag_sja1105.c
index 83e4136..1a85125 100644 (file)
--- a/net/dsa/tag_sja1105.c
+++ b/net/dsa/tag_sja1105.c
@@ -665,7 +665,8 @@ static struct sk_buff *sja1110_rcv_inband_control_extension(struct sk_buff *skb,
                 * padding and trailer we need to account for the fact that
                 * skb->data points to skb_mac_header(skb) + ETH_HLEN.
                 */
-               pskb_trim_rcsum(skb, start_of_padding - ETH_HLEN);
+               if (pskb_trim_rcsum(skb, start_of_padding - ETH_HLEN))
+                       return NULL;
        /* Trap-to-host frame, no timestamp trailer */
        } else {
                *source_port = SJA1110_RX_HEADER_SRC_PORT(rx_header);