Piteball
/
android_kernel_samsung_msm8226
mirror of https://github.com/S3NEO/android_kernel_samsung_msm8226.git
1
0
Fork 0
Code Issues Packages Projects Releases Wiki Activity

BACKPORT: packet: in packet_do_bind, test fanout with bind_lock held 

[ Upstream commit 4971613c1639d8e5f102c4e797c3bf8f83a5a69e ]

Once a socket has po->fanout set, it remains a member of the group
until it is destroyed. The prot_hook must be constant and identical
across sockets in the group.

If fanout_add races with packet_do_bind between the test of po->fanout
and taking the lock, the bind call may make type or dev inconsistent
with that of the fanout group.

Hold po->bind_lock when testing po->fanout to avoid this race.

I had to introduce artificial delay (local_bh_enable) to actually
observe the race.

Bug: 69160446
Fixes: dc99f60069 ("packet: Add fanout support.")
Change-Id: I899f9b6bcbd1d4b033388ef22c472857574bfc30
Signed-off-by: Willem de Bruijn <willemb@google.com>
Reviewed-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Marissa Wall <marissaw@google.com>
Signed-off-by: Siqi Lin <siqilin@google.com>
CVE-2017-15649
Signed-off-by: Kevin F. Haggerty <haggertk@lineageos.org>
This commit is contained in:
Marissa Wall 2017-11-16 16:56:10 -08:00 committed by Francescodario Cuzzocrea
parent 346a910ec8
commit 7f03a90e40
1 changed files with 8 additions and 5 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

13
net/packet/af_packet.c
View File

@ -2479,17 +2479,20 @@ static int packet_release(struct socket *sock)
static int packet_do_bind(struct sock *sk, struct net_device *dev, __be16 protocol)
{
struct packet_sock *po = pkt_sk(sk);
int ret = 0;
lock_sock(sk);
spin_lock(&po->bind_lock);
if (po->fanout) {
if (dev)
dev_put(dev);
return -EINVAL;
ret = -EINVAL;
goto out_unlock;
}
lock_sock(sk);
spin_lock(&po->bind_lock);
unregister_prot_hook(sk, true);
po->num = protocol;
po->prot_hook.type = protocol;
@ -2513,7 +2516,7 @@ static int packet_do_bind(struct sock *sk, struct net_device *dev, __be16 protoc
out_unlock:
spin_unlock(&po->bind_lock);
release_sock(sk);
return 0;
return ret;
}
/*