From 512efafc7ec4dbc40094a462c4689a156d06dded Mon Sep 17 00:00:00 2001
From: Alami-Amine <aalami90@gmail.com>
Date: Fri, 13 Sep 2024 17:33:45 +0200
Subject: [PATCH] fixing ubsan issues

---
 src/lib/support/BufferWriter.cpp |  6 ++++--
 src/lib/support/CHIPMemString.h  | 13 ++++++++++---
 2 files changed, 14 insertions(+), 5 deletions(-)

diff --git a/src/lib/support/BufferWriter.cpp b/src/lib/support/BufferWriter.cpp
index c606cba6e2b37d..2ba03e22d24e03 100644
--- a/src/lib/support/BufferWriter.cpp
+++ b/src/lib/support/BufferWriter.cpp
@@ -73,8 +73,9 @@ LittleEndian::BufferWriter & LittleEndian::BufferWriter::EndianPutSigned(int64_t
 
 BigEndian::BufferWriter & BigEndian::BufferWriter::EndianPut(uint64_t x, size_t size)
 {
-    while (size-- > 0)
+    while (size > 0)
     {
+        size--;
         Put(static_cast<uint8_t>((x >> (size * 8)) & 0xff));
     }
     return *this;
@@ -82,8 +83,9 @@ BigEndian::BufferWriter & BigEndian::BufferWriter::EndianPut(uint64_t x, size_t
 
 BigEndian::BufferWriter & BigEndian::BufferWriter::EndianPutSigned(int64_t x, size_t size)
 {
-    while (size-- > 0)
+    while (size > 0)
     {
+        size--;
         Put(static_cast<uint8_t>((x >> (size * 8)) & 0xff));
     }
     return *this;
diff --git a/src/lib/support/CHIPMemString.h b/src/lib/support/CHIPMemString.h
index 51341192a76250..f15003b8a2d354 100644
--- a/src/lib/support/CHIPMemString.h
+++ b/src/lib/support/CHIPMemString.h
@@ -84,9 +84,16 @@ inline void CopyString(char * dest, size_t destLength, ByteSpan source)
 {
     if (dest && destLength)
     {
-        size_t maxChars = std::min(destLength - 1, source.size());
-        memcpy(dest, source.data(), maxChars);
-        dest[maxChars] = '\0';
+        if (!source.empty())
+        {
+            size_t maxChars = std::min(destLength - 1, source.size());
+            memcpy(dest, source.data(), maxChars);
+            dest[maxChars] = '\0';
+        }
+        else
+        {
+            dest[0] = '\0';
+        }
     }
 }