[PATCH v3 3/3] net: dsa: sja1105: Check return value

[Artem Chernyshev]

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@xxxxxxxxxxx>
---
V1->V2 Fixes for tag_hellcreek.c and tag_sja1105.c
V2->V3 Split patch in 3 separate parts

 net/dsa/tag_sja1105.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/net/dsa/tag_sja1105.c b/net/dsa/tag_sja1105.c
index 83e4136516b0..1a85125bda6d 100644
--- 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);
-- 
2.30.3