diff mbox series

[v3] net: usb: lan78xx: Limit packet length to skb->len

Message ID 20230318092552.93145-1-szymon.heidrich@gmail.com
State Superseded
Headers show
Series [v3] net: usb: lan78xx: Limit packet length to skb->len | expand

Commit Message

Szymon Heidrich March 18, 2023, 9:25 a.m. UTC
Packet length retrieved from descriptor may be larger than
the actual socket buffer length. In such case the cloned
skb passed up the network stack will leak kernel memory contents.

Additionally prevent integer underflow when size is less than
ETH_FCS_LEN.

Fixes: 55d7de9de6c3 ("Microchip's LAN7800 family USB 2/3 to 10/100/1000 Ethernet device driver")
Signed-off-by: Szymon Heidrich <szymon.heidrich@gmail.com>
---
V1 -> V2: Fix ISO C90 forbids mixed declarations and code
V2 -> V3: Removed the Reported-by tag

 drivers/net/usb/lan78xx.c | 18 +++++++++++++++++-
 1 file changed, 17 insertions(+), 1 deletion(-)

Comments

patchwork-bot+netdevbpf@kernel.org March 20, 2023, 10:20 a.m. UTC | #1
Hello:

This patch was applied to netdev/net.git (main)
by David S. Miller <davem@davemloft.net>:

On Sat, 18 Mar 2023 10:25:52 +0100 you wrote:
> Packet length retrieved from descriptor may be larger than
> the actual socket buffer length. In such case the cloned
> skb passed up the network stack will leak kernel memory contents.
> 
> Additionally prevent integer underflow when size is less than
> ETH_FCS_LEN.
> 
> [...]

Here is the summary with links:
  - [v3] net: usb: lan78xx: Limit packet length to skb->len
    https://git.kernel.org/netdev/net/c/7f247f5a2c18

You are awesome, thank you!
diff mbox series

Patch

diff --git a/drivers/net/usb/lan78xx.c b/drivers/net/usb/lan78xx.c
index 068488890..c458c030f 100644
--- a/drivers/net/usb/lan78xx.c
+++ b/drivers/net/usb/lan78xx.c
@@ -3579,13 +3579,29 @@  static int lan78xx_rx(struct lan78xx_net *dev, struct sk_buff *skb,
 		size = (rx_cmd_a & RX_CMD_A_LEN_MASK_);
 		align_count = (4 - ((size + RXW_PADDING) % 4)) % 4;
 
+		if (unlikely(size > skb->len)) {
+			netif_dbg(dev, rx_err, dev->net,
+				  "size err rx_cmd_a=0x%08x\n",
+				  rx_cmd_a);
+			return 0;
+		}
+
 		if (unlikely(rx_cmd_a & RX_CMD_A_RED_)) {
 			netif_dbg(dev, rx_err, dev->net,
 				  "Error rx_cmd_a=0x%08x", rx_cmd_a);
 		} else {
-			u32 frame_len = size - ETH_FCS_LEN;
+			u32 frame_len;
 			struct sk_buff *skb2;
 
+			if (unlikely(size < ETH_FCS_LEN)) {
+				netif_dbg(dev, rx_err, dev->net,
+					  "size err rx_cmd_a=0x%08x\n",
+					  rx_cmd_a);
+				return 0;
+			}
+
+			frame_len = size - ETH_FCS_LEN;
+
 			skb2 = napi_alloc_skb(&dev->napi, frame_len);
 			if (!skb2)
 				return 0;