From 4f791a8f09472ffac7df1c7e8a12de52f80082b1 Mon Sep 17 00:00:00 2001
From: Silvano Seva <silseva@fastwebnet.it>
Date: Mon, 23 Dec 2024 12:40:57 +0100
Subject: [PATCH] M17: FrameDecoder: decodeLich: added validation of LICH chunk
 number

---
 openrtx/src/protocols/M17/M17FrameDecoder.cpp | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/openrtx/src/protocols/M17/M17FrameDecoder.cpp b/openrtx/src/protocols/M17/M17FrameDecoder.cpp
index c35a2643..1c6685f0 100644
--- a/openrtx/src/protocols/M17/M17FrameDecoder.cpp
+++ b/openrtx/src/protocols/M17/M17FrameDecoder.cpp
@@ -202,8 +202,12 @@ bool M17FrameDecoder::decodeLich(std::array < uint8_t, 6 >& segment,
     }
 
     // Last byte of the segment contains the segment number, shift left
-    // by five when packing the LICH.
+    // by five when packing the LICH. The segment number must range between
+    // zero and five.
     segment[5] >>= 5;
 
+    if(segment[5] > 5)
+        return false;
+
     return true;
 }