This is a note to let you know that I've just added the patch titled net: xilinx_emaclite: fix receive buffer overflow to the 4.9-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary The filename of the patch is: net-xilinx_emaclite-fix-receive-buffer-overflow.patch and it can be found in the queue-4.9 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let <stable@xxxxxxxxxxxxxxx> know about it. >From foo@baz Thu Jun 15 09:31:48 CEST 2017 From: Anssi Hannula <anssi.hannula@xxxxxxxxxx> Date: Tue, 23 May 2017 21:53:29 -0400 Subject: net: xilinx_emaclite: fix receive buffer overflow From: Anssi Hannula <anssi.hannula@xxxxxxxxxx> [ 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 <anssi.hannula@xxxxxxxxxx> Fixes: bb81b2ddfa19 ("net: add Xilinx emac lite device driver") Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx> Signed-off-by: Sasha Levin <alexander.levin@xxxxxxxxxxx> Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- drivers/net/ethernet/xilinx/xilinx_emaclite.c | 10 +++++++--- 1 file changed, 7 insertions(+), 3 deletions(-) --- a/drivers/net/ethernet/xilinx/xilinx_emaclite.c +++ b/drivers/net/ethernet/xilinx/xilinx_emaclite.c @@ -377,7 +377,7 @@ static int xemaclite_send_data(struct ne * * 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; @@ -417,7 +417,7 @@ static u16 xemaclite_recv_data(struct ne /* 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 + @@ -425,6 +425,7 @@ static u16 xemaclite_recv_data(struct ne 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) @@ -437,6 +438,9 @@ static u16 xemaclite_recv_data(struct ne /* 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); @@ -611,7 +615,7 @@ static void xemaclite_rx_handler(struct 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++; Patches currently in stable-queue which might be from anssi.hannula@xxxxxxxxxx are queue-4.9/net-xilinx_emaclite-fix-freezes-due-to-unordered-i-o.patch queue-4.9/net-xilinx_emaclite-fix-receive-buffer-overflow.patch