From: Szymon Heidrich szymon.heidrich@gmail.com
[ 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: Szymon Heidrich szymon.heidrich@gmail.com Link: https://lore.kernel.org/r/20230316110540.77531-1-szymon.heidrich@gmail.com Signed-off-by: Jakub Kicinski kuba@kernel.org Signed-off-by: Sasha Levin sashal@kernel.org --- 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 db34f8d1d6051..5d6454fedb3f1 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);