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Commit e0d07a32 authored by Szymon Heidrich's avatar Szymon Heidrich Committed by Greg Kroah-Hartman
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net: usb: smsc75xx: Move packet length check to prevent kernel panic in skb_pull 



[ Upstream commit 43ffe6caccc7a1bb9d7442fbab521efbf6c1378c ]

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: default avatarSzymon Heidrich <szymon.heidrich@gmail.com>
Link: https://lore.kernel.org/r/20230316110540.77531-1-szymon.heidrich@gmail.com


Signed-off-by: default avatarJakub Kicinski <kuba@kernel.org>
Signed-off-by: default avatarSasha Levin <sashal@kernel.org>
parent 5c06bd3d

drivers/net/usb/smsc75xx.c

+8 −2
Original line number Diff line number Diff line
@@ -2198,6 +2198,13 @@ 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);
@@ -2210,8 +2217,7 @@ 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);