tree d5c2e9caa911e825ee996671c8c68d94384dd4e4
parent 4f1b17edf982380ee455252802a778699ac3841c
author Kyle Zeng <zengyhkyle@gmail.com> 1694754777 -0700
committer Anil Altinay <aaltinay@google.com> 1698982375 +0000

ipv4: fix null-deref in ipv4_link_failure

[ Upstream commit 0113d9c9d1ccc07f5a3710dac4aa24b6d711278c ]

Currently, we assume the skb is associated with a device before calling
__ip_options_compile, which is not always the case if it is re-routed by
ipvs.
When skb->dev is NULL, dev_net(skb->dev) will become null-dereference.
This patch adds a check for the edge case and switch to use the net_device
from the rtable when skb->dev is NULL.

BUG=b/304963328
TEST=presubmit
RELEASE_NOTE=Fixes CVE-2023-42754 in the Linux kernel.

Fixes: ed0de45a1008 ("ipv4: recompile ip options in ipv4_link_failure")
Suggested-by: David Ahern <dsahern@kernel.org>
Signed-off-by: Kyle Zeng <zengyhkyle@gmail.com>
Cc: Stephen Suryaputra <ssuryaextr@gmail.com>
Cc: Vadim Fedorenko <vfedorenko@novek.ru>
Reviewed-by: David Ahern <dsahern@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Sasha Levin <sashal@kernel.org>
Change-Id: I557d52e7be43131c3657bd66226e80d32b9d3d6b
Reviewed-on: https://cos-review.googlesource.com/c/third_party/kernel/+/60618
Tested-by: Cusky Presubmit Bot <presubmit@cos-infra-prod.iam.gserviceaccount.com>
Reviewed-by: Oleksandr Tymoshenko <ovt@google.com>