[msg] Initialize session counters with random per spec.

project-chip · Dec 2, 2021 · 0babc91 · 0babc91
1 parent e66e2a1
commit 0babc91
Showing 1 changed file with 7 additions and 2 deletions.
diff --git a/src/transport/MessageCounter.h b/src/transport/MessageCounter.h
@@ -21,6 +21,7 @@
  */
 #pragma once
 
+#include <crypto/RandUtils.h>
 #include <lib/support/PersistedCounter.h>
 
 namespace chip {
@@ -106,8 +107,12 @@ class GlobalEncryptedMessageCounter : public MessageCounter
 class LocalSessionMessageCounter : public MessageCounter
 {
 public:
-    static constexpr uint32_t kInitialValue = 1;
-    LocalSessionMessageCounter() : value(kInitialValue) {}
+    static constexpr uint32_t kInitialValue = 1; ///< Used for initializing peer counter
+
+    /**
+     * Initialize a local message counter with random value between [0, 2^28-1].
+     */
+    LocalSessionMessageCounter() { value = Crypto::GetRandU32() & 0x0FFFFFFF; }
 
     Type GetType() override { return Session; }
     uint32_t Value() override { return value; }