hardening: safer strncpy

Author: mkalkbrenner

src/ZeDMD.cpp

@@ -945,7 +945,7 @@ ZEDMDAPI void ZeDMD_SetLogCallback(ZeDMD* pZeDMD, ZeDMD_LogCallback callback, co
 
 ZEDMDAPI const char* ZeDMD_FormatLogMessage(const char* format, va_list args, const void* pUserData)
 {
-  char buffer[1024];
+  static thread_local char buffer[1024];
   vsnprintf(buffer, sizeof(buffer), format, args);
 
   return buffer;

src/ZeDMDComm.cpp

@@ -338,19 +338,28 @@ bool ZeDMDComm::IsQueueEmpty()
 
 void ZeDMDComm::IgnoreDevice(const char* ignore_device)
 {
-  if (sizeof(ignore_device) < 32 && m_ignoredDevicesCounter < 10)
+  if (!ignore_device || m_ignoredDevicesCounter >= 10)
   {
-    strcpy(&m_ignoredDevices[m_ignoredDevicesCounter++][0], ignore_device);
+    return;
   }
+
+  const size_t maxLen = sizeof(m_ignoredDevices[0]) - 1;
+  strncpy(&m_ignoredDevices[m_ignoredDevicesCounter][0], ignore_device, maxLen);
+  m_ignoredDevices[m_ignoredDevicesCounter][maxLen] = '\0';
+  ++m_ignoredDevicesCounter;
 }
 
 void ZeDMDComm::SetDevice(const char* device)
 {
-  if (sizeof(device) < 32)
+  if (!device)
   {
-    strcpy(m_device, device);
-    m_autoDetect = false;
+    return;
   }
+
+  const size_t maxLen = sizeof(m_device) - 1;
+  strncpy(m_device, device, maxLen);
+  m_device[maxLen] = '\0';
+  m_autoDetect = false;
 }
 
 bool ZeDMDComm::Connect()