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 <szymon.heidrich@xxxxxxxxx>
---
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
