From ac21e00fa160988619c6a8a55967a92f436fb54b Mon Sep 17 00:00:00 2001
From: Jonathan Hui <jonhui@google.com>
Date: Fri, 4 Jun 2021 13:06:24 -0700
Subject: [PATCH] [mac] avoid potential assert with SetKeyId() on an invalid
 frame (#6704)

---
 src/core/mac/sub_mac.cpp | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/src/core/mac/sub_mac.cpp b/src/core/mac/sub_mac.cpp
index fea69f28b..750c8d5fe 100644
--- a/src/core/mac/sub_mac.cpp
+++ b/src/core/mac/sub_mac.cpp
@@ -331,14 +331,14 @@ void SubMac::ProcessTransmitSecurity(void)
     VerifyOrExit(mTransmitFrame.GetSecurityEnabled());
     VerifyOrExit(!mTransmitFrame.IsSecurityProcessed());
 
+    SuccessOrExit(mTransmitFrame.GetKeyIdMode(keyIdMode));
+
     if (!mTransmitFrame.IsARetransmission())
     {
         mTransmitFrame.SetKeyId(mKeyId);
     }
 
     VerifyOrExit(ShouldHandleTransmitSecurity());
-
-    SuccessOrExit(mTransmitFrame.GetKeyIdMode(keyIdMode));
     VerifyOrExit(keyIdMode == Frame::kKeyIdMode1);
 
     mTransmitFrame.SetAesKey(GetCurrentMacKey());