2023-03-16 11:06:48

by Szymon Heidrich

Subject: [PATCH] net: usb: smsc75xx: Move packet length check to prevent kernel panic in skb_pull

Packet length check needs to be located after size and align_count
calculation to prevent kernel panic in skb_pull() in case
rx_cmd_a & RX_CMD_A_RED evaluates to true.

Fixes: d8b228318935 ("net: usb: smsc75xx: Limit packet length to skb->len")
Signed-off-by: Szymon Heidrich <[email protected]>
---
drivers/net/usb/smsc75xx.c | 10 ++++++++--
1 file changed, 8 insertions(+), 2 deletions(-)

diff --git a/drivers/net/usb/smsc75xx.c b/drivers/net/usb/smsc75xx.c
index db34f8d1d..5d6454fed 100644
--- a/drivers/net/usb/smsc75xx.c
+++ b/drivers/net/usb/smsc75xx.c
@@ -2200,6 +2200,13 @@ static int smsc75xx_rx_fixup(struct usbnet *dev, struct sk_buff *skb)
size = (rx_cmd_a & RX_CMD_A_LEN) - RXW_PADDING;
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\n", rx_cmd_a);
@@ -2212,8 +2219,7 @@ static int smsc75xx_rx_fixup(struct usbnet *dev, struct sk_buff *skb)
dev->net->stats.rx_frame_errors++;
} else {
/* MAX_SINGLE_PACKET_SIZE + 4(CRC) + 2(COE) + 4(Vlan) */
- if (unlikely(size > (MAX_SINGLE_PACKET_SIZE + ETH_HLEN + 12) ||
- size > skb->len)) {
+ if (unlikely(size > (MAX_SINGLE_PACKET_SIZE + ETH_HLEN + 12))) {
netif_dbg(dev, rx_err, dev->net,
"size err rx_cmd_a=0x%08x\n",
rx_cmd_a);
--
2.40.0

2023-03-17 00:30:29

by patchwork-bot+netdevbpf

Subject: Re: [PATCH] net: usb: smsc75xx: Move packet length check to prevent kernel panic in skb_pull

Hello:

This patch was applied to netdev/net.git (main)
by Jakub Kicinski <[email protected]>:

On Thu, 16 Mar 2023 12:05:40 +0100 you wrote:
> Packet length check needs to be located after size and align_count
> calculation to prevent kernel panic in skb_pull() in case
> rx_cmd_a & RX_CMD_A_RED evaluates to true.
>
> Fixes: d8b228318935 ("net: usb: smsc75xx: Limit packet length to skb->len")
> Signed-off-by: Szymon Heidrich <[email protected]>
>
> [...]

Here is the summary with links:
- net: usb: smsc75xx: Move packet length check to prevent kernel panic in skb_pull
https://git.kernel.org/netdev/net/c/43ffe6caccc7

You are awesome, thank you!
--
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