This is a note to let you know that I've just added the patch titled
net: llc: add lock_sock in llc_ui_bind to avoid a race condition
to the 3.18-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git%3Ba=su...
The filename of the patch is: net-llc-add-lock_sock-in-llc_ui_bind-to-avoid-a-race-condition.patch and it can be found in the queue-3.18 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree, please let stable@vger.kernel.org know about it.
From foo@baz Tue Apr 10 13:58:07 CEST 2018
From: linzhang xiaolou4617@gmail.com Date: Thu, 25 May 2017 14:07:18 +0800 Subject: net: llc: add lock_sock in llc_ui_bind to avoid a race condition
From: linzhang xiaolou4617@gmail.com
[ 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 --- net/llc/af_llc.c | 3 +++ 1 file changed, 3 insertions(+)
--- a/net/llc/af_llc.c +++ b/net/llc/af_llc.c @@ -309,6 +309,8 @@ static int llc_ui_bind(struct socket *so int rc = -EINVAL;
dprintk("%s: binding %02X\n", __func__, addr->sllc_sap); + + lock_sock(sk); if (unlikely(!sock_flag(sk, SOCK_ZAPPED) || addrlen != sizeof(*addr))) goto out; rc = -EAFNOSUPPORT; @@ -380,6 +382,7 @@ static int llc_ui_bind(struct socket *so out_put: llc_sap_put(sap); out: + release_sock(sk); return rc; }
Patches currently in stable-queue which might be from xiaolou4617@gmail.com are
queue-3.18/net-x25-fix-one-potential-use-after-free-issue.patch queue-3.18/net-llc-add-lock_sock-in-llc_ui_bind-to-avoid-a-race-condition.patch