[PATCH 3.18 04/22] bgmac: add check for oversized packets

[Greg Kroah-Hartman <gregkh@linuxfoundation.org>]

3.18-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Felix Fietkau <nbd@openwrt.org>

commit 6a6c708469c9e10fd87adcc3abff164270538d62 upstream.

In very rare cases, the MAC can catch an internal buffer that is bigger
than it's supposed to be. Instead of crashing the kernel, simply pass
the buffer back to the hardware

Signed-off-by: Felix Fietkau <nbd@openwrt.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Amit Pundir <amit.pundir@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
 drivers/net/ethernet/broadcom/bgmac.c |    7 +++++++
 1 file changed, 7 insertions(+)

--- a/drivers/net/ethernet/broadcom/bgmac.c
+++ b/drivers/net/ethernet/broadcom/bgmac.c
@@ -373,6 +373,13 @@ static int bgmac_dma_rx_read(struct bgma
 				break;
 			}
 
+			if (len > BGMAC_RX_ALLOC_SIZE) {
+				bgmac_err(bgmac, "Found oversized packet at slot %d, DMA issue!\n",
+					  ring->start);
+				put_page(virt_to_head_page(buf));
+				break;
+			}
+
 			/* Omit CRC. */
 			len -= ETH_FCS_LEN;