From 9283413c4c9327196f03f0716a2948ef954ba0c8 Mon Sep 17 00:00:00 2001
From: paul-szczepanek-arm
 <33840200+paul-szczepanek-arm@users.noreply.github.com>
Date: Thu, 29 Mar 2018 15:44:15 +0100
Subject: [PATCH] count failures, trigger reparing when verification fails

---
 .../ble/generic/GenericSecurityManager.h      |  4 +++-
 .../FEATURE_BLE/ble/pal/PalSecurityManager.h  |  4 ++--
 .../source/generic/GenericSecurityManager.cpp | 21 +++++++++++++++----
 3 files changed, 22 insertions(+), 7 deletions(-)

diff --git a/features/FEATURE_BLE/ble/generic/GenericSecurityManager.h b/features/FEATURE_BLE/ble/generic/GenericSecurityManager.h
index a8a82a7a77..211e97ad6a 100644
--- a/features/FEATURE_BLE/ble/generic/GenericSecurityManager.h
+++ b/features/FEATURE_BLE/ble/generic/GenericSecurityManager.h
@@ -454,6 +454,8 @@ private:
         uint8_t oob_mitm_protection:1;
         uint8_t oob_present:1;
         uint8_t legacy_pairing_oob_request_pending:1;
+
+        uint8_t mic_failures:2;
     };
 
     pal::SecurityManager &_pal;
@@ -526,7 +528,7 @@ public:
 
     /** @copydoc ble::pal::SecurityManager::on_invalid_mic
      */
-    virtual void on_invalid_mic(
+    virtual void on_signature_verification_failure(
         connection_handle_t connection
     );
 
diff --git a/features/FEATURE_BLE/ble/pal/PalSecurityManager.h b/features/FEATURE_BLE/ble/pal/PalSecurityManager.h
index dcdc194e51..9b98f8e3b7 100644
--- a/features/FEATURE_BLE/ble/pal/PalSecurityManager.h
+++ b/features/FEATURE_BLE/ble/pal/PalSecurityManager.h
@@ -281,12 +281,12 @@ public:
         ) = 0;
 
         /**
-         * Indicate that the MIC verification has failed. This could
+         * Indicate that signed data was rejected due to verification failure. This could
          * be due to an invalid CSRK key.
          *
          * @param[in] connection connection handle
          */
-        virtual void on_invalid_mic(
+        virtual void on_signature_verification_failure(
             connection_handle_t connection
         ) = 0;
 
diff --git a/features/FEATURE_BLE/source/generic/GenericSecurityManager.cpp b/features/FEATURE_BLE/source/generic/GenericSecurityManager.cpp
index 3f5bf678f2..801569e4a3 100644
--- a/features/FEATURE_BLE/source/generic/GenericSecurityManager.cpp
+++ b/features/FEATURE_BLE/source/generic/GenericSecurityManager.cpp
@@ -942,9 +942,21 @@ void GenericSecurityManager::on_valid_mic_timeout(connection_handle_t connection
     (void)connection;
 }
 
-void GenericSecurityManager::on_invalid_mic(connection_handle_t connection) {
-    (void)connection;
-    /* TODO: count and re-pair when threshold reached */
+void GenericSecurityManager::on_signature_verification_failure(connection_handle_t connection) {
+    ControlBlock_t *cb = get_control_block(connection);
+    if (!cb) {
+        return;
+    }
+
+    cb->mic_failures++;
+    if (cb->mic_failures == 3) {
+        cb->mic_failures = 0;
+        if (cb->is_master) {
+           requestPairing(connection);
+        } else {
+           slave_security_request(connection);
+        }
+    }
 }
 
 void GenericSecurityManager::on_slave_security_request(
@@ -1263,7 +1275,8 @@ GenericSecurityManager::ControlBlock_t::ControlBlock_t() :
     attempt_oob(false),
     oob_mitm_protection(false),
     oob_present(false),
-    legacy_pairing_oob_request_pending(false) { }
+    legacy_pairing_oob_request_pending(false),
+    mic_failures(0) { }
 
 void GenericSecurityManager::on_ltk_request(connection_handle_t connection)
 {