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authorlinzhang <xiaolou4617@gmail.com>2017-05-25 09:07:18 +0300
committerDavid S. Miller <davem@davemloft.net>2017-05-26 21:20:29 +0300
commit0908cf4dfef35fc6ac12329007052ebe93ff1081 (patch)
tree84925b3d7052ed3117939b267024da24d680d00e
parent797a93647a48d6cb8a20641a86a71713a947f786 (diff)
downloadlinux-0908cf4dfef35fc6ac12329007052ebe93ff1081.tar.xz
net: llc: add lock_sock in llc_ui_bind to avoid a race condition
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>
-rw-r--r--net/llc/af_llc.c3
1 files changed, 3 insertions, 0 deletions
diff --git a/net/llc/af_llc.c b/net/llc/af_llc.c
index 8364fe5b59e4..c38d16f22d2a 100644
--- a/net/llc/af_llc.c
+++ b/net/llc/af_llc.c
@@ -311,6 +311,8 @@ static int llc_ui_bind(struct socket *sock, struct sockaddr *uaddr, int addrlen)
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;
@@ -382,6 +384,7 @@ static int llc_ui_bind(struct socket *sock, struct sockaddr *uaddr, int addrlen)
out_put:
llc_sap_put(sap);
out:
+ release_sock(sk);
return rc;
}