Bluetooth: Fix redundant encryption when receiving Security Request

If we're already encrypted with a good enough LTK we should just ignore
an incoming SMP Security Request. The code was already taking care of
this in the smp_conn_security function before calling smp_ltk_encrypt
but failed to do the same in smp_cmd_security_req. This patch fixes the
issue by moving up the smp_sufficient_security function and using it in
the Security Request handler before trying to request encryption.

Signed-off-by: Johan Hedberg <johan.hedberg@intel.com>
Signed-off-by: Marcel Holtmann <marcel@holtmann.org>

1 files changed, 14 insertions, 11 deletions

diff --git a/net/bluetooth/smp.c b/net/bluetooth/smp.c
index 35f57090ddd0..6ce7785a2708 100644
--- a/net/bluetooth/smp.c
+++ b/net/bluetooth/smp.c
@@ -859,6 +859,17 @@ static bool smp_ltk_encrypt(struct l2cap_conn *conn, u8 sec_level)
         return true;
 }
 
+bool smp_sufficient_security(struct hci_conn *hcon, u8 sec_level)
+{
+        if (sec_level == BT_SECURITY_LOW)
+                return true;
+
+        if (hcon->sec_level >= sec_level)
+                return true;
+
+        return false;
+}
+
 static u8 smp_cmd_security_req(struct l2cap_conn *conn, struct sk_buff *skb)
 {
         struct smp_cmd_security_req *rp = (void *) skb->data;
@@ -876,6 +887,9 @@ static u8 smp_cmd_security_req(struct l2cap_conn *conn, struct sk_buff *skb)
                 return SMP_CMD_NOTSUPP;
 
         sec_level = authreq_to_seclevel(rp->auth_req);
+        if (smp_sufficient_security(hcon, sec_level))
+                return 0;
+
         if (sec_level > hcon->pending_sec_level)
                 hcon->pending_sec_level = sec_level;
 
@@ -904,17 +918,6 @@ static u8 smp_cmd_security_req(struct l2cap_conn *conn, struct sk_buff *skb)
         return 0;
 }
 
-bool smp_sufficient_security(struct hci_conn *hcon, u8 sec_level)
-{
-        if (sec_level == BT_SECURITY_LOW)
-                return true;
-
-        if (hcon->sec_level >= sec_level)
-                return true;
-
-        return false;
-}
-
 int smp_conn_security(struct hci_conn *hcon, __u8 sec_level)
 {
         struct l2cap_conn *conn = hcon->l2cap_data;