[PATCH net-next v2 04/10] net: niu: check for failure when pulling in the RX header

[Josef Bacik <josef@toxicpanda.com>]

niu_process_rx_pkt() uses __pskb_pull_tail() to pull the hardware RX
header and the Ethernet header into the skb head, and ignores the
return value.  If that pull failed, the skb_pull() of the RX header
right after it would BUG() in __skb_pull().

It doesn't fail today because the skb is freshly allocated, isn't
shared and has room in the head.  Use pskb_may_pull() anyway and drop
the packet if it fails, rather than depending on that.

Assisted-by: LLM
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
---
 drivers/net/ethernet/sun/niu.c | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/drivers/net/ethernet/sun/niu.c b/drivers/net/ethernet/sun/niu.c
index c74a97fe5464..d1c0e868004d 100644
--- a/drivers/net/ethernet/sun/niu.c
+++ b/drivers/net/ethernet/sun/niu.c
@@ -3488,7 +3488,11 @@ static int niu_process_rx_pkt(struct napi_struct *napi, struct niu *np,
 
 	len += sizeof(*rh);
 	len = min_t(int, len, sizeof(*rh) + VLAN_ETH_HLEN);
-	__pskb_pull_tail(skb, len);
+	if (unlikely(!pskb_may_pull(skb, len))) {
+		rp->rx_dropped++;
+		kfree_skb(skb);
+		return num_rcr;
+	}
 
 	rh = (struct rx_pkt_hdr1 *) skb->data;
 	if (np->dev->features & NETIF_F_RXHASH)

-- 
2.55.0