Subject: [PATCH] dl2k: Fix potential NULL pointer dereference in receive_packet()

From: Rand Deeb <[email-masked]>
Date: Tue, 13 Feb 2024 23:09:00 +0300

This patch addresses a potential NULL pointer dereference issue in the
receive_packet() function of the dl2k network driver. Previously, there was
a possibility of dereferencing a NULL pointer when the pointer 'skb'
returned from the function 'netdev_alloc_skb_ip_align()' was not checked
before being used. To resolve this issue, the patch introduces a check to
ensure that 'skb' is not NULL before dereferencing it.

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

Signed-off-by: Rand Deeb <[email-masked]>
---
 drivers/net/ethernet/dlink/dl2k.c | 8 ++++++++
 1 file changed, 8 insertions(+)

diff --git a/drivers/net/ethernet/dlink/dl2k.c b/drivers/net/ethernet/dlink/dl2k.c
index 734acb834c98..9cee510247e1 100644
--- a/drivers/net/ethernet/dlink/dl2k.c
+++ b/drivers/net/ethernet/dlink/dl2k.c
@@ -972,6 +972,14 @@ receive_packet (struct net_device *dev)
 							   np->rx_buf_sz,
 							   DMA_FROM_DEVICE);
 			}
+			if (skb == NULL) {
+				np->rx_ring[entry].fraginfo = 0;
+				printk (KERN_INFO
+				       "%s: receive_packet: "
+				       "Unable to re-allocate Rx skbuff.#%d\n",
+				       dev->name, entry);
+				break;
+			}
 			skb->protocol = eth_type_trans (skb, dev);
 #if 0
 			/* Checksum done by hw, but csum value unavailable. */
-- 
2.34.1