Commit 9bf0b2cf authored Jan 27, 2022 by Shyam Sundar S K Committed by Pavel Machek Mar 16, 2022

net: amd-xgbe: Fix skb data length underflow

commit 5aac9108a180fc06e28d4e7fb00247ce603b72ee upstream.

There will be BUG_ON() triggered in include/linux/skbuff.h leading to
intermittent kernel panic, when the skb length underflow is detected.

Fix this by dropping the packet if such length underflows are seen
because of inconsistencies in the hardware descriptors.

Fixes: 622c36f143fc ("amd-xgbe: Fix jumbo MTU processing on newer hardware")
Suggested-by: Tom Lendacky <thomas.lendacky@amd.com>
Signed-off-by: Shyam Sundar S K <Shyam-sundar.S-k@amd.com>
Acked-by: Tom Lendacky <thomas.lendacky@amd.com>
Link: https://lore.kernel.org/r/20220127092003.2812745-1-Shyam-sundar.S-k@amd.com

Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

parent 475a5269

drivers/net/ethernet/amd/xgbe/xgbe-drv.c

+11 −1

Original line number	Diff line number	Diff line
		@@ -1976,6 +1976,14 @@ read_again:
		buf2_len = xgbe_rx_buf2_len(rdata, packet, len);
		len += buf2_len;

		if (buf2_len > rdata->rx.buf.dma_len) {
		/* Hardware inconsistency within the descriptors
		* that has resulted in a length underflow.
		*/
		error = 1;
		goto skip_data;
		}

		if (!skb) {
		skb = xgbe_create_skb(pdata, napi, rdata,
		buf1_len);
		@@ -2005,8 +2013,10 @@ skip_data:
		if (!last \|\| context_next)
		goto read_again;

		if (!skb)
		if (!skb \|\| error) {
		dev_kfree_skb(skb);
		goto next_packet;
		}

		/* Be sure we don't exceed the configured MTU */
		max_len = netdev->mtu + ETH_HLEN;