From 8980298abd5f3615ed3d33eb0574b5490c556f19 Mon Sep 17 00:00:00 2001
From: Matthias Ringwald <matthias@ringwald.ch>
Date: Wed, 5 Oct 2022 14:20:57 +0200
Subject: [PATCH] sm: add distributed key validation ability

---
 src/ble/sm.c | 21 ++++++++++++++++-----
 1 file changed, 16 insertions(+), 5 deletions(-)

diff --git a/src/ble/sm.c b/src/ble/sm.c
index db0e03b80..d2d6ed25e 100644
--- a/src/ble/sm.c
+++ b/src/ble/sm.c
@@ -1530,8 +1530,24 @@ static void sm_store_bonding_information(sm_connection_t * sm_conn){
     }
 }
 
+static void sm_pairing_error(sm_connection_t * sm_conn, uint8_t reason){
+    sm_conn->sm_pairing_failed_reason = reason;
+    sm_conn->sm_engine_state = SM_GENERAL_SEND_PAIRING_FAILED;
+}
+
+static uint8_t sm_key_distribution_validate_received(sm_connection_t * sm_conn){
+    return 0;
+}
+
 static void sm_key_distribution_handle_all_received(sm_connection_t * sm_conn){
 
+    // abort pairing if received keys are not valid
+    uint8_t reason = sm_key_distribution_validate_received(sm_conn);
+    if (reason != 0){
+        sm_pairing_error(sm_conn, reason);
+        return;
+    }
+
     // only store pairing information if both sides are bondable, i.e., the bonadble flag is set
     bool bonding_enabled = (sm_pairing_packet_get_auth_req(setup->sm_m_preq)
                             & sm_pairing_packet_get_auth_req(setup->sm_s_pres)
@@ -1544,11 +1560,6 @@ static void sm_key_distribution_handle_all_received(sm_connection_t * sm_conn){
     }
 }
 
-static void sm_pairing_error(sm_connection_t * sm_conn, uint8_t reason){
-    sm_conn->sm_pairing_failed_reason = reason;
-    sm_conn->sm_engine_state = SM_GENERAL_SEND_PAIRING_FAILED;
-}
-
 static inline void sm_pdu_received_in_wrong_state(sm_connection_t * sm_conn){
     sm_pairing_error(sm_conn, SM_REASON_UNSPECIFIED_REASON);
 }