This is a note to let you know that I've just added the patch titled
packet: fix tp_reserve race in packet_set_ring
to the 4.9-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
packet-fix-tp_reserve-race-in-packet_set_ring.patch
and it can be found in the queue-4.9 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From foo@baz Fri Aug 11 09:10:20 PDT 2017
From: Willem de Bruijn <willemb@xxxxxxxxxx>
Date: Thu, 10 Aug 2017 12:41:58 -0400
Subject: packet: fix tp_reserve race in packet_set_ring
From: Willem de Bruijn <willemb@xxxxxxxxxx>
[ Upstream commit c27927e372f0785f3303e8fad94b85945e2c97b7 ]
Updates to tp_reserve can race with reads of the field in
packet_set_ring. Avoid this by holding the socket lock during
updates in setsockopt PACKET_RESERVE.
This bug was discovered by syzkaller.
Fixes: 8913336a7e8d ("packet: add PACKET_RESERVE sockopt")
Reported-by: Andrey Konovalov <andreyknvl@xxxxxxxxxx>
Signed-off-by: Willem de Bruijn <willemb@xxxxxxxxxx>
Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
net/packet/af_packet.c | 13 +++++++++----
1 file changed, 9 insertions(+), 4 deletions(-)
--- a/net/packet/af_packet.c
+++ b/net/packet/af_packet.c
@@ -3698,14 +3698,19 @@ packet_setsockopt(struct socket *sock, i
if (optlen != sizeof(val))
return -EINVAL;
- if (po->rx_ring.pg_vec || po->tx_ring.pg_vec)
- return -EBUSY;
if (copy_from_user(&val, optval, sizeof(val)))
return -EFAULT;
if (val > INT_MAX)
return -EINVAL;
- po->tp_reserve = val;
- return 0;
+ lock_sock(sk);
+ if (po->rx_ring.pg_vec || po->tx_ring.pg_vec) {
+ ret = -EBUSY;
+ } else {
+ po->tp_reserve = val;
+ ret = 0;
+ }
+ release_sock(sk);
+ return ret;
}
case PACKET_LOSS:
{
Patches currently in stable-queue which might be from willemb@xxxxxxxxxx are
queue-4.9/net-avoid-skb_warn_bad_offload-false-positives-on-ufo.patch
queue-4.9/packet-fix-tp_reserve-race-in-packet_set_ring.patch
queue-4.9/udp-consistently-apply-ufo-or-fragmentation.patch