Do not try to allocate memory on de-serialization when there is no need

to do so(empty strings).
Also, do not attempt to free a string if empty.

Author: Shumaro

src/lib/support/SerializationUtils.cpp

@@ -877,18 +877,23 @@ WEAVE_ERROR ReadDataForType(TLVReader &aReader, void *aStructureData, const Fiel
 
         case SerializedFieldTypeUTF8String:
         {
-            char *dst = NULL;
             // TLV Strings are not null terminated
             uint32_t length = aReader.GetLength() + 1;
 
-            dst = (char *)memMgmt->mem_alloc(length);
-            VerifyOrExit(dst != NULL, err = WEAVE_ERROR_NO_MEMORY);
+            if (length > 1)
+            {
+                char *dst = NULL;
 
-            err = aReader.GetString(dst, length);
-            SuccessOrExit(err);
+                dst = (char *)memMgmt->mem_alloc(length);
+                VerifyOrExit(dst != NULL, err = WEAVE_ERROR_NO_MEMORY);
+
+                err = aReader.GetString(dst, length);
+                SuccessOrExit(err);
 
-            LogReadWrite("%s utf8string '%s' allocating %d bytes at %p", "R", dst, length, dst);
-            *static_cast<char**>(aStructureData) = dst;
+                LogReadWrite("%s utf8string '%s' allocating %d bytes at %p", "R", dst, length, dst);
+
+                *static_cast<char**>(aStructureData) = dst;
+            }
             break;
         }
 
@@ -897,12 +902,16 @@ WEAVE_ERROR ReadDataForType(TLVReader &aReader, void *aStructureData, const Fiel
             SerializedByteString byteString;
             byteString.mLen = aReader.GetLength();
 
-            byteString.mBuf = static_cast<uint8_t *>(memMgmt->mem_alloc(byteString.mLen));
-            VerifyOrExit(byteString.mBuf != NULL, err = WEAVE_ERROR_NO_MEMORY);
-            aReader.GetBytes(byteString.mBuf, byteString.mLen);
+            if (byteString.mLen > 0)
+            {
+                byteString.mBuf = static_cast<uint8_t *>(memMgmt->mem_alloc(byteString.mLen));
+                VerifyOrExit(byteString.mBuf != NULL, err = WEAVE_ERROR_NO_MEMORY);
+                aReader.GetBytes(byteString.mBuf, byteString.mLen);
+
+                LogReadWrite("%s bytestring allocated %d bytes at %p", "R", byteString.mLen, byteString.mBuf);
 
-            LogReadWrite("%s bytestring allocated %d bytes at %p", "R", byteString.mLen, byteString.mBuf);
-            *static_cast<SerializedByteString *>(aStructureData) = byteString;
+                *static_cast<SerializedByteString *>(aStructureData) = byteString;
+            }
             break;
         }
 
@@ -1298,10 +1307,13 @@ WEAVE_ERROR DeallocateDeserializedArray(void *aArrayData,
 
     if (aFieldDescriptors == NULL)
     {
-        LogReadWrite("%s Freeing array of primitive type at 0x%x", "R", array->mElementBuffer);
+        // The elements are of a primitive type, we can free the array now if not empty
+        if (array->mNumElements > 0)
+        {
+            LogReadWrite("%s Freeing array of primitive type at 0x%x", "R", array->mElementBuffer);
 
-        // The elements are of a primitive type, we can free the array now.
-        memMgmt->mem_free(array->mElementBuffer);
+            memMgmt->mem_free(array->mElementBuffer);
+        }
     }
     else
     {
@@ -1377,10 +1389,14 @@ WEAVE_ERROR DeallocateDeserializedStructure(void *aStructureData,
             {
                 char *str = *((char **)currentFieldData);
 
-                LogReadWrite("%s Freeing UTF8String '%s' at 0x%x", "R", str, str);
+                // Go ahead and free it here if not empty.
+                if (!(*str == 0))
+                {
+                    LogReadWrite("%s Freeing UTF8String '%s' at 0x%x", "R", str, str);
+
+                    memMgmt->mem_free(str);
+                }
 
-                // Go ahead and free it here.
-                memMgmt->mem_free(str);
                 break;
             }