Bluetooth: Remove LTK re-encryption procedure

Due to several devices being unable to handle this procedure reliably
(resulting in forced disconnections before pairing completes) it's
better to remove it altogether.

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

2 files changed, 7 insertions, 49 deletions

diff --git a/net/bluetooth/smp.c b/net/bluetooth/smp.c
index b952041bf4ac..10a8e622ab2b 100644
--- a/net/bluetooth/smp.c
+++ b/net/bluetooth/smp.c
@@ -556,20 +556,6 @@ error:
         smp_failure(conn, reason);
 }
 
-static void smp_reencrypt(struct work_struct *work)
-{
-        struct smp_chan *smp = container_of(work, struct smp_chan,
-                                            reencrypt.work);
-        struct l2cap_conn *conn = smp->conn;
-        struct hci_conn *hcon = conn->hcon;
-        struct smp_ltk *ltk = smp->ltk;
-
-        BT_DBG("");
-
-        hci_le_start_enc(hcon, ltk->ediv, ltk->rand, ltk->val);
-        hcon->enc_key_size = ltk->enc_size;
-}
-
 static struct smp_chan *smp_chan_create(struct l2cap_conn *conn)
 {
         struct smp_chan *smp;
@@ -580,7 +566,6 @@ static struct smp_chan *smp_chan_create(struct l2cap_conn *conn)
 
         INIT_WORK(&smp->confirm, confirm_work);
         INIT_WORK(&smp->random, random_work);
-        INIT_DELAYED_WORK(&smp->reencrypt, smp_reencrypt);
 
         smp->conn = conn;
         conn->smp_chan = smp;
@@ -598,8 +583,6 @@ void smp_chan_destroy(struct l2cap_conn *conn)
 
         BUG_ON(!smp);
 
-        cancel_delayed_work_sync(&smp->reencrypt);
-
         complete = test_bit(SMP_FLAG_COMPLETE, &smp->smp_flags);
         mgmt_smp_complete(conn->hcon, complete);
 
@@ -1276,7 +1259,6 @@ int smp_distribute_keys(struct l2cap_conn *conn)
         struct smp_chan *smp = conn->smp_chan;
         struct hci_conn *hcon = conn->hcon;
         struct hci_dev *hdev = hcon->hdev;
-        bool ltk_encrypt;
         __u8 *keydist;
 
         BT_DBG("conn %p", conn);
@@ -1376,32 +1358,12 @@ int smp_distribute_keys(struct l2cap_conn *conn)
         if ((smp->remote_key_dist & 0x07))
                 return 0;
 
-        /* Check if we should try to re-encrypt the link with the LTK.
-         * SMP_FLAG_LTK_ENCRYPT flag is used to track whether we've
-         * already tried this (in which case we shouldn't try again).
-         *
-         * The request will trigger an encryption key refresh event
-         * which will cause a call to auth_cfm and eventually lead to
-         * l2cap_core.c calling this smp_distribute_keys function again
-         * and thereby completing the process.
-         */
-        if (smp->ltk)
-                ltk_encrypt = !test_and_set_bit(SMP_FLAG_LTK_ENCRYPT,
-                                                &smp->smp_flags);
-        else
-                ltk_encrypt = false;
+        clear_bit(HCI_CONN_LE_SMP_PEND, &hcon->flags);
+        cancel_delayed_work_sync(&conn->security_timer);
+        set_bit(SMP_FLAG_COMPLETE, &smp->smp_flags);
+        smp_notify_keys(conn);
 
-        /* Re-encrypt the link with LTK if possible */
-        if (ltk_encrypt && hcon->out) {
-                queue_delayed_work(hdev->req_workqueue, &smp->reencrypt,
-                                   SMP_REENCRYPT_TIMEOUT);
-        } else {
-                clear_bit(HCI_CONN_LE_SMP_PEND, &hcon->flags);
-                cancel_delayed_work_sync(&conn->security_timer);
-                set_bit(SMP_FLAG_COMPLETE, &smp->smp_flags);
-                smp_notify_keys(conn);
-                smp_chan_destroy(conn);
-        }
+        smp_chan_destroy(conn);
 
         return 0;
 }
diff --git a/net/bluetooth/smp.h b/net/bluetooth/smp.h
index 0d536b8b3f9a..1277147a9150 100644
--- a/net/bluetooth/smp.h
+++ b/net/bluetooth/smp.h
@@ -118,11 +118,8 @@ struct smp_cmd_security_req {
 #define SMP_FLAG_TK_VALID       1
 #define SMP_FLAG_CFM_PENDING    2
 #define SMP_FLAG_MITM_AUTH      3
-#define SMP_FLAG_LTK_ENCRYPT    4
-#define SMP_FLAG_COMPLETE       5
-#define SMP_FLAG_INITIATOR      6
-
-#define SMP_REENCRYPT_TIMEOUT   msecs_to_jiffies(500)
+#define SMP_FLAG_COMPLETE       4
+#define SMP_FLAG_INITIATOR      5
 
 struct smp_chan {
         struct l2cap_conn *conn;
@@ -145,7 +142,6 @@ struct smp_chan {
         unsigned long   smp_flags;
         struct work_struct confirm;
         struct work_struct random;
-        struct delayed_work reencrypt;
 };
 
 /* SMP Commands */