Patch "net: xilinx_emaclite: fix receive buffer overflow" has been added to the 4.9-stable tree

[<gregkh@linuxfoundation.org>]

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@vger.kernel.org> know about it.


>From foo@baz Thu Jun 15 09:31:48 CEST 2017
From: Anssi Hannula <anssi.hannula@bitwise.fi>
Date: Tue, 23 May 2017 21:53:29 -0400
Subject: net: xilinx_emaclite: fix receive buffer overflow

From: Anssi Hannula <anssi.hannula@bitwise.fi>


[ 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@bitwise.fi>
Fixes: bb81b2ddfa19 ("net: add Xilinx emac lite device driver")
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Sasha Levin <alexander.levin@verizon.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
 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@bitwise.fi 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