diff options
| author | Quang Le <quanglex97@gmail.com> | 2025-08-01 13:54:16 -0400 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2025-08-15 16:39:31 +0200 |
| commit | f1791fd7b845bea0ce9674fcf2febee7bc87a893 (patch) | |
| tree | 0a7a6b56d6b577107b4c5d900f5a6b18bbedf832 | |
| parent | 8b09bb5c42024d50cfeee0f45f29f43fb6652057 (diff) | |
net/packet: fix a race in packet_set_ring() and packet_notifier()
commit 01d3c8417b9c1b884a8a981a3b886da556512f36 upstream.
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.
Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2")
Cc: stable@vger.kernel.org
Signed-off-by: Quang Le <quanglex97@gmail.com>
Signed-off-by: Willem de Bruijn <willemb@google.com>
Link: https://patch.msgid.link/20250801175423.2970334-1-willemdebruijn.kernel@gmail.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
| -rw-r--r-- | net/packet/af_packet.c | 12 |
1 files changed, 6 insertions, 6 deletions
diff --git a/net/packet/af_packet.c b/net/packet/af_packet.c index be608f07441f..c7c7de3403f7 100644 --- a/net/packet/af_packet.c +++ b/net/packet/af_packet.c @@ -4573,10 +4573,10 @@ static int packet_set_ring(struct sock *sk, union tpacket_req_u *req_u, spin_lock(&po->bind_lock); was_running = packet_sock_flag(po, PACKET_SOCK_RUNNING); num = po->num; - if (was_running) { - WRITE_ONCE(po->num, 0); + WRITE_ONCE(po->num, 0); + if (was_running) __unregister_prot_hook(sk, false); - } + spin_unlock(&po->bind_lock); synchronize_net(); @@ -4608,10 +4608,10 @@ static int packet_set_ring(struct sock *sk, union tpacket_req_u *req_u, mutex_unlock(&po->pg_vec_lock); spin_lock(&po->bind_lock); - if (was_running) { - WRITE_ONCE(po->num, num); + WRITE_ONCE(po->num, num); + if (was_running) register_prot_hook(sk); - } + spin_unlock(&po->bind_lock); if (pg_vec && (po->tp_version > TPACKET_V2)) { /* Because we don't support block-based V3 on tx-ring */ |