tree 67f5a1b713357ce9e4cb3a875a4bf26ff8d1e7ab
parent a74bec409e337ea020306908aed16febab3fd356
author linzhang <xiaolou4617@gmail.com> 1495692438 +0800
committer Greg Kroah-Hartman <gregkh@linuxfoundation.org> 1523641687 +0200

net: llc: add lock_sock in llc_ui_bind to avoid a race condition


[ Upstream commit 0908cf4dfef35fc6ac12329007052ebe93ff1081 ]

There is a race condition in llc_ui_bind if two or more processes/threads
try to bind a same socket.

If more processes/threads bind a same socket success that will lead to
two problems, one is this action is not what we expected, another is
will lead to kernel in unstable status or oops(in my simple test case,
cause llc2.ko can't unload).

The current code is test SOCK_ZAPPED bit to avoid a process to
bind a same socket twice but that is can't avoid more processes/threads
try to bind a same socket at the same time.

So, add lock_sock in llc_ui_bind like others, such as llc_ui_connect.

Signed-off-by: Lin Zhang <xiaolou4617@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Sasha Levin <alexander.levin@microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>