From 10a7629772676694cb4da272df2b391f1963fc7d Mon Sep 17 00:00:00 2001 From: Anssi Hannula Date: Tue, 23 May 2017 21:53:29 -0400 Subject: [PATCH] net: xilinx_emaclite: fix receive buffer overflow [ Upstream commit cd224553641848dd17800fe559e4ff5d208553e8 ] xilinx_emaclite looks at the received data to try to determine the Ethernet packet length but does not properly clamp it if proto_type == ETH_P_IP or 1500 < proto_type <= 1518, causing a buffer overflow and a panic via skb_panic() as the length exceeds the allocated skb size. Fix those cases. Also add an additional unconditional check with WARN_ON() at the end. Signed-off-by: Anssi Hannula Fixes: bb81b2ddfa19 ("net: add Xilinx emac lite device driver") Signed-off-by: David S. Miller Signed-off-by: Sasha Levin Signed-off-by: Greg Kroah-Hartman --- drivers/net/ethernet/xilinx/xilinx_emaclite.c | 10 +++++++--- 1 file changed, 7 insertions(+), 3 deletions(-) diff --git a/drivers/net/ethernet/xilinx/xilinx_emaclite.c b/drivers/net/ethernet/xilinx/xilinx_emaclite.c index 73d1657..4cb8b85 100644 --- a/drivers/net/ethernet/xilinx/xilinx_emaclite.c +++ b/drivers/net/ethernet/xilinx/xilinx_emaclite.c @@ -379,7 +379,7 @@ static int xemaclite_send_data(struct net_local *drvdata, u8 *data, * * Return: Total number of bytes received */ -static u16 xemaclite_recv_data(struct net_local *drvdata, u8 *data) +static u16 xemaclite_recv_data(struct net_local *drvdata, u8 *data, int maxlen) { void __iomem *addr; u16 length, proto_type; @@ -419,7 +419,7 @@ static u16 xemaclite_recv_data(struct net_local *drvdata, u8 *data) /* Check if received ethernet frame is a raw ethernet frame * or an IP packet or an ARP packet */ - if (proto_type > (ETH_FRAME_LEN + ETH_FCS_LEN)) { + if (proto_type > ETH_DATA_LEN) { if (proto_type == ETH_P_IP) { length = ((ntohl(xemaclite_readl(addr + @@ -427,6 +427,7 @@ static u16 xemaclite_recv_data(struct net_local *drvdata, u8 *data) XEL_RXBUFF_OFFSET)) >> XEL_HEADER_SHIFT) & XEL_RPLR_LENGTH_MASK); + length = min_t(u16, length, ETH_DATA_LEN); length += ETH_HLEN + ETH_FCS_LEN; } else if (proto_type == ETH_P_ARP) @@ -439,6 +440,9 @@ static u16 xemaclite_recv_data(struct net_local *drvdata, u8 *data) /* Use the length in the frame, plus the header and trailer */ length = proto_type + ETH_HLEN + ETH_FCS_LEN; + if (WARN_ON(length > maxlen)) + length = maxlen; + /* Read from the EmacLite device */ xemaclite_aligned_read((u32 __force *) (addr + XEL_RXBUFF_OFFSET), data, length); @@ -613,7 +617,7 @@ static void xemaclite_rx_handler(struct net_device *dev) skb_reserve(skb, 2); - len = xemaclite_recv_data(lp, (u8 *) skb->data); + len = xemaclite_recv_data(lp, (u8 *) skb->data, len); if (!len) { dev->stats.rx_errors++; -- 2.7.4