[Bluetooth] Add locking for bt_proto array manipulation

The bt_proto array needs to be protected by some kind of locking to
prevent a race condition between bt_sock_create and bt_sock_register.

And in addition all calls to sk_alloc need to be made GFP_ATOMIC now.

Signed-off-by: Masatake YAMATO <jet@gyve.org>
Signed-off-by: Frederik Deweerdt <frederik.deweerdt@gmail.com>
Signed-off-by: Marcel Holtmann <marcel@holtmann.org>

1 files changed, 29 insertions, 7 deletions

diff --git a/net/bluetooth/af_bluetooth.c b/net/bluetooth/af_bluetooth.c
index a91fee4f2705..67df99e2e5c8 100644
--- a/net/bluetooth/af_bluetooth.c
+++ b/net/bluetooth/af_bluetooth.c
@@ -53,36 +53,51 @@
 /* Bluetooth sockets */
 #define BT_MAX_PROTO    8
 static struct net_proto_family *bt_proto[BT_MAX_PROTO];
+static DEFINE_RWLOCK(bt_proto_lock);
 
 int bt_sock_register(int proto, struct net_proto_family *ops)
 {
+        int err = 0;
+
         if (proto < 0 || proto >= BT_MAX_PROTO)
                 return -EINVAL;
 
+        write_lock(&bt_proto_lock);
+
         if (bt_proto[proto])
-                return -EEXIST;
+                err = -EEXIST;
+        else
+                bt_proto[proto] = ops;
 
-        bt_proto[proto] = ops;
-        return 0;
+        write_unlock(&bt_proto_lock);
+
+        return err;
 }
 EXPORT_SYMBOL(bt_sock_register);
 
 int bt_sock_unregister(int proto)
 {
+        int err = 0;
+
         if (proto < 0 || proto >= BT_MAX_PROTO)
                 return -EINVAL;
 
+        write_lock(&bt_proto_lock);
+
         if (!bt_proto[proto])
-                return -ENOENT;
+                err = -ENOENT;
+        else
+                bt_proto[proto] = NULL;
 
-        bt_proto[proto] = NULL;
-        return 0;
+        write_unlock(&bt_proto_lock);
+
+        return err;
 }
 EXPORT_SYMBOL(bt_sock_unregister);
 
 static int bt_sock_create(struct socket *sock, int proto)
 {
-        int err = 0;
+        int err;
 
         if (proto < 0 || proto >= BT_MAX_PROTO)
                 return -EINVAL;
@@ -92,11 +107,18 @@ static int bt_sock_create(struct socket *sock, int proto)
                 request_module("bt-proto-%d", proto);
         }
 #endif
+
         err = -EPROTONOSUPPORT;
+
+        read_lock(&bt_proto_lock);
+
         if (bt_proto[proto] && try_module_get(bt_proto[proto]->owner)) {
                 err = bt_proto[proto]->create(sock, proto);
                 module_put(bt_proto[proto]->owner);
         }
+
+        read_unlock(&bt_proto_lock);
+
         return err; 
 }