net/tls: Only attach to sockets in ESTABLISHED state
[ Upstream commit d91c3e17f75f218022140dee18cf515292184a8f ]
Calling accept on a TCP socket with a TLS ulp attached results
in two sockets that share the same ulp context.
The ulp context is freed while a socket is destroyed, so
after one of the sockets is released, the second second will
trigger a use after free when it tries to access the ulp context
attached to it.
We restrict the TLS ulp to sockets in ESTABLISHED state
to prevent the scenario above.
Fixes: 3c4d7559159b ("tls: kernel TLS support")
Reported-by: syzbot+904e7cd6c5c741609228@syzkaller.appspotmail.com
Signed-off-by: Ilya Lesokhin <ilyal@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
diff --git a/net/tls/tls_main.c b/net/tls/tls_main.c
index 60aff60..7075709 100644
--- a/net/tls/tls_main.c
+++ b/net/tls/tls_main.c
@@ -444,6 +444,15 @@ static int tls_init(struct sock *sk)
struct tls_context *ctx;
int rc = 0;
+ /* The TLS ulp is currently supported only for TCP sockets
+ * in ESTABLISHED state.
+ * Supporting sockets in LISTEN state will require us
+ * to modify the accept implementation to clone rather then
+ * share the ulp context.
+ */
+ if (sk->sk_state != TCP_ESTABLISHED)
+ return -ENOTSUPP;
+
/* allocate tls context */
ctx = kzalloc(sizeof(*ctx), GFP_KERNEL);
if (!ctx) {