[hal] Fix potential gamedata out of bounds read (#3983)

The size was uninitialized. If the size is smaller than the data, NetComm just updates the size and does not initialize the data.
wpilibsuite · Feb 2, 2022 · fcf23fc · fcf23fc
1 parent af5ef51
commit fcf23fc
Showing 1 changed file with 5 additions and 0 deletions.
diff --git a/hal/src/main/native/athena/FRCDriverStation.cpp b/hal/src/main/native/athena/FRCDriverStation.cpp
@@ -110,10 +110,15 @@ static int32_t HAL_GetControlWordInternal(HAL_ControlWord* controlWord) {
 
 static int32_t HAL_GetMatchInfoInternal(HAL_MatchInfo* info) {
   MatchType_t matchType = MatchType_t::kMatchType_none;
+  info->gameSpecificMessageSize = sizeof(info->gameSpecificMessage);
   int status = FRC_NetworkCommunication_getMatchInfo(
       info->eventName, &matchType, &info->matchNumber, &info->replayNumber,
       info->gameSpecificMessage, &info->gameSpecificMessageSize);
 
+  if (info->gameSpecificMessageSize > sizeof(info->gameSpecificMessage)) {
+    info->gameSpecificMessageSize = 0;
+  }
+
   info->matchType = static_cast<HAL_MatchType>(matchType);
 
   *(std::end(info->eventName) - 1) = '\0';