1 files changed, 46 insertions, 14 deletions

diff --git a/net/bluetooth/smp.c b/net/bluetooth/smp.c
index f2829a7932e2..e33a982161c1 100644
--- a/net/bluetooth/smp.c
+++ b/net/bluetooth/smp.c
@@ -385,6 +385,16 @@ static const u8 gen_method[5][5] = {
         { CFM_PASSKEY, CFM_PASSKEY, REQ_PASSKEY, JUST_WORKS, OVERLAP     },
 };
 
+static u8 get_auth_method(struct smp_chan *smp, u8 local_io, u8 remote_io)
+{
+        /* If either side has unknown io_caps, use JUST WORKS */
+        if (local_io > SMP_IO_KEYBOARD_DISPLAY ||
+            remote_io > SMP_IO_KEYBOARD_DISPLAY)
+                return JUST_WORKS;
+
+        return gen_method[remote_io][local_io];
+}
+
 static int tk_request(struct l2cap_conn *conn, u8 remote_oob, u8 auth,
                                                 u8 local_io, u8 remote_io)
 {
@@ -401,14 +411,11 @@ static int tk_request(struct l2cap_conn *conn, u8 remote_oob, u8 auth,
         BT_DBG("tk_request: auth:%d lcl:%d rem:%d", auth, local_io, remote_io);
 
         /* If neither side wants MITM, use JUST WORKS */
-        /* If either side has unknown io_caps, use JUST WORKS */
         /* Otherwise, look up method from the table */
-        if (!(auth & SMP_AUTH_MITM) ||
-            local_io > SMP_IO_KEYBOARD_DISPLAY ||
-            remote_io > SMP_IO_KEYBOARD_DISPLAY)
+        if (!(auth & SMP_AUTH_MITM))
                 method = JUST_WORKS;
         else
-                method = gen_method[remote_io][local_io];
+                method = get_auth_method(smp, local_io, remote_io);
 
         /* If not bonding, don't ask user to confirm a Zero TK */
         if (!(auth & SMP_AUTH_BONDING) && method == JUST_CFM)
@@ -669,7 +676,7 @@ static u8 smp_cmd_pairing_req(struct l2cap_conn *conn, struct sk_buff *skb)
 {
         struct smp_cmd_pairing rsp, *req = (void *) skb->data;
         struct smp_chan *smp;
-        u8 key_size, auth;
+        u8 key_size, auth, sec_level;
         int ret;
 
         BT_DBG("conn %p", conn);
@@ -695,7 +702,19 @@ static u8 smp_cmd_pairing_req(struct l2cap_conn *conn, struct sk_buff *skb)
         /* We didn't start the pairing, so match remote */
         auth = req->auth_req;
 
-        conn->hcon->pending_sec_level = authreq_to_seclevel(auth);
+        sec_level = authreq_to_seclevel(auth);
+        if (sec_level > conn->hcon->pending_sec_level)
+                conn->hcon->pending_sec_level = sec_level;
+
+        /* If we need MITM check that it can be acheived */
+        if (conn->hcon->pending_sec_level >= BT_SECURITY_HIGH) {
+                u8 method;
+
+                method = get_auth_method(smp, conn->hcon->io_capability,
+                                         req->io_capability);
+                if (method == JUST_WORKS || method == JUST_CFM)
+                        return SMP_AUTH_REQUIREMENTS;
+        }
 
         build_pairing_cmd(conn, req, &rsp, auth);
 
@@ -743,6 +762,16 @@ static u8 smp_cmd_pairing_rsp(struct l2cap_conn *conn, struct sk_buff *skb)
         if (check_enc_key_size(conn, key_size))
                 return SMP_ENC_KEY_SIZE;
 
+        /* If we need MITM check that it can be acheived */
+        if (conn->hcon->pending_sec_level >= BT_SECURITY_HIGH) {
+                u8 method;
+
+                method = get_auth_method(smp, req->io_capability,
+                                         rsp->io_capability);
+                if (method == JUST_WORKS || method == JUST_CFM)
+                        return SMP_AUTH_REQUIREMENTS;
+        }
+
         get_random_bytes(smp->prnd, sizeof(smp->prnd));
 
         smp->prsp[0] = SMP_CMD_PAIRING_RSP;
@@ -838,6 +867,7 @@ static u8 smp_cmd_security_req(struct l2cap_conn *conn, struct sk_buff *skb)
         struct smp_cmd_pairing cp;
         struct hci_conn *hcon = conn->hcon;
         struct smp_chan *smp;
+        u8 sec_level;
 
         BT_DBG("conn %p", conn);
 
@@ -847,7 +877,9 @@ static u8 smp_cmd_security_req(struct l2cap_conn *conn, struct sk_buff *skb)
         if (!(conn->hcon->link_mode & HCI_LM_MASTER))
                 return SMP_CMD_NOTSUPP;
 
-        hcon->pending_sec_level = authreq_to_seclevel(rp->auth_req);
+        sec_level = authreq_to_seclevel(rp->auth_req);
+        if (sec_level > hcon->pending_sec_level)
+                hcon->pending_sec_level = sec_level;
 
         if (smp_ltk_encrypt(conn, hcon->pending_sec_level))
                 return 0;
@@ -901,9 +933,12 @@ int smp_conn_security(struct hci_conn *hcon, __u8 sec_level)
         if (smp_sufficient_security(hcon, sec_level))
                 return 1;
 
+        if (sec_level > hcon->pending_sec_level)
+                hcon->pending_sec_level = sec_level;
+
         if (hcon->link_mode & HCI_LM_MASTER)
-                if (smp_ltk_encrypt(conn, sec_level))
-                        goto done;
+                if (smp_ltk_encrypt(conn, hcon->pending_sec_level))
+                        return 0;
 
         if (test_and_set_bit(HCI_CONN_LE_SMP_PEND, &hcon->flags))
                 return 0;
@@ -918,7 +953,7 @@ int smp_conn_security(struct hci_conn *hcon, __u8 sec_level)
          * requires it.
          */
         if (hcon->io_capability != HCI_IO_NO_INPUT_OUTPUT ||
-            sec_level > BT_SECURITY_MEDIUM)
+            hcon->pending_sec_level > BT_SECURITY_MEDIUM)
                 authreq |= SMP_AUTH_MITM;
 
         if (hcon->link_mode & HCI_LM_MASTER) {
@@ -937,9 +972,6 @@ int smp_conn_security(struct hci_conn *hcon, __u8 sec_level)
 
         set_bit(SMP_FLAG_INITIATOR, &smp->flags);
 
-done:
-        hcon->pending_sec_level = sec_level;
-
         return 0;
 }