tree 7b80fcacb49ea539c788f6997b5a94ba91f52693
parent f3840362814ca21bfa6f70c6c38074ad51ecce48
author He Gao <hegao@google.com> 1755207368 +0000
committer He Gao <hegao@google.com> 1755226612 -0700

net/packet: fix a race in packet_set_ring() and packet_notifier()

upstream commit: 01d3c8417b9c1b884a8a981a3b886da556512f36

When packet_set_ring() releases po->bind_lock, another thread can
run packet_notifier() and process an NETDEV_UP event.

This race and the fix are both similar to that of commit 15fe076edea7
("net/packet: fix a race in packet_bind() and packet_notifier()").

There too the packet_notifier NETDEV_UP event managed to run while a
po->bind_lock critical section had to be temporarily released. And
the fix was similarly to temporarily set po->num to zero to keep
the socket unhooked until the lock is retaken.

The po->bind_lock in packet_set_ring and packet_notifier precede the
introduction of git history.

BUG=b/438677841
TEST=presubmit
RELEASE_NOTE=Fixed KCTF-01d3c84 in the Linux kernel.

cos-patch: security-high
Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2")
Cc: stable@vger.kernel.org
Change-Id: I7efa71cc24262d1658ab2669798793eb5954ad2c
Signed-off-by: Quang Le <quanglex97@gmail.com>
Signed-off-by: Willem de Bruijn <willemb@google.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Reviewed-on: https://cos-review.googlesource.com/c/third_party/kernel/+/109090
Tested-by: Cusky Presubmit Bot <presubmit@cos-infra-prod.iam.gserviceaccount.com>
Reviewed-by: Kevin Berry <kpberry@google.com>
Main-Branch-Verified: Cusky Presubmit Bot <presubmit@cos-infra-prod.iam.gserviceaccount.com>