netdev - [PATCH net v4] net: dlink: handle copy

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [day] [month] [year] [list]

Message-ID: <20250928190124.1156-1-yyyynoom@gmail.com>
Date: Mon, 29 Sep 2025 04:01:24 +0900
From: Yeounsu Moon <yyyynoom@...il.com>
To: Andrew Lunn <andrew+netdev@...n.ch>,
	"David S. Miller" <davem@...emloft.net>,
	Eric Dumazet <edumazet@...gle.com>,
	Jakub Kicinski <kuba@...nel.org>,
	Paolo Abeni <pabeni@...hat.com>
Cc: netdev@...r.kernel.org,
	linux-kernel@...r.kernel.org,
	Yeounsu Moon <yyyynoom@...il.com>,
	Andrew Lunn <andrew@...n.ch>
Subject: [PATCH net v4] net: dlink: handle copy_thresh allocation failure

The driver did not handle failure of `netdev_alloc_skb_ip_align()`.
If the allocation failed, dereferencing `skb->protocol` could lead to
a NULL pointer dereference.

This patch tries to allocate `skb`. If the allocation fails, it falls
back to the normal path.

Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2")
Suggested-by: Jakub Kicinski <kuba@...nel.org>
Tested-on: D-Link DGE-550T Rev-A3
Signed-off-by: Yeounsu Moon <yyyynoom@...il.com>
Reviewed-by: Andrew Lunn <andrew@...n.ch>
---
 drivers/net/ethernet/dlink/dl2k.c | 7 +++++--
 1 file changed, 5 insertions(+), 2 deletions(-)
---
Changelog:
v4:
- consolidated into a single patch
- removed goto statement, per Jakub's suggestion
- reorder changelog for clarity
v3: https://lore.kernel.org/netdev/20250916183305.2808-1-yyyynoom@gmail.com/
- change confusing label name
v2: https://lore.kernel.org/netdev/20250914182653.3152-4-yyyynoom@gmail.com/
- split into two patches: whitespace cleanup and functional fix
v1: https://lore.kernel.org/netdev/20250912145339.67448-2-yyyynoom@gmail.com/
---

diff --git a/drivers/net/ethernet/dlink/dl2k.c b/drivers/net/ethernet/dlink/dl2k.c
index 6bbf6e5584e5..1996d2e4e3e2 100644
--- a/drivers/net/ethernet/dlink/dl2k.c
+++ b/drivers/net/ethernet/dlink/dl2k.c
@@ -964,15 +964,18 @@ receive_packet (struct net_device *dev)
 		} else {
 			struct sk_buff *skb;
 
+			skb = NULL;
 			/* Small skbuffs for short packets */
-			if (pkt_len > copy_thresh) {
+			if (pkt_len <= copy_thresh)
+				skb = netdev_alloc_skb_ip_align(dev, pkt_len);
+			if (!skb) {
 				dma_unmap_single(&np->pdev->dev,
 						 desc_to_dma(desc),
 						 np->rx_buf_sz,
 						 DMA_FROM_DEVICE);
 				skb_put (skb = np->rx_skbuff[entry], pkt_len);
 				np->rx_skbuff[entry] = NULL;
-			} else if ((skb = netdev_alloc_skb_ip_align(dev, pkt_len))) {
+			} else {
 				dma_sync_single_for_cpu(&np->pdev->dev,
 							desc_to_dma(desc),
 							np->rx_buf_sz,
-- 
2.51.0