Fix exception propagation on packet decompression (#365)

Author: lionkor

include/Common.h

@@ -127,7 +127,7 @@ class Application final {
     static inline std::mutex mShutdownHandlersMutex {};
     static inline std::deque<TShutdownHandler> mShutdownHandlers {};
 
-    static inline Version mVersion { 3, 5, 0 };
+    static inline Version mVersion { 3, 5, 1 };
 };
 
 void SplitString(std::string const& str, const char delim, std::vector<std::string>& out);
@@ -268,3 +268,9 @@ std::vector<uint8_t> DeComp(std::span<const uint8_t> input);
 
 std::string GetPlatformAgnosticErrorString();
 #define S_DSN SU_RAW
+
+class InvalidDataError : std::runtime_error {
+public:
+    InvalidDataError() : std::runtime_error("Invalid data") {
+    }
+};

src/Common.cpp

@@ -418,7 +418,11 @@ std::vector<uint8_t> DeComp(std::span<const uint8_t> input) {
             output_size = output_buffer.size();
         } else if (res != Z_OK) {
             beammp_error("zlib uncompress() failed: " + std::to_string(res));
-            throw std::runtime_error("zlib uncompress() failed");
+            if (res == Z_DATA_ERROR) {
+                throw InvalidDataError {};
+            } else {
+                throw std::runtime_error("zlib uncompress() failed");
+            }
         } else if (res == Z_OK) {
             break;
         }

src/TNetwork.cpp

@@ -546,7 +546,17 @@ std::vector<uint8_t> TNetwork::TCPRcv(TClient& c) {
     constexpr std::string_view ABG = "ABG:";
     if (Data.size() >= ABG.size() && std::equal(Data.begin(), Data.begin() + ABG.size(), ABG.begin(), ABG.end())) {
         Data.erase(Data.begin(), Data.begin() + ABG.size());
-        return DeComp(Data);
+        try {
+            return DeComp(Data);
+        } catch (const InvalidDataError& ) {
+            beammp_errorf("Failed to decompress packet from a client. The receive failed and the client may be disconnected as a result");
+            // return empty -> error
+            return std::vector<uint8_t>();
+        } catch (const std::runtime_error& e) {
+            beammp_errorf("Failed to decompress packet from a client: {}. The server may be out of RAM! The receive failed and the client may be disconnected as a result", e.what());
+            // return empty -> error
+            return std::vector<uint8_t>();
+        }
     } else {
         return Data;
     }

src/TServer.cpp

@@ -165,7 +165,19 @@ void TServer::GlobalParser(const std::weak_ptr<TClient>& Client, std::vector<uin
     constexpr std::string_view ABG = "ABG:";
     if (Packet.size() >= ABG.size() && std::equal(Packet.begin(), Packet.begin() + ABG.size(), ABG.begin(), ABG.end())) {
         Packet.erase(Packet.begin(), Packet.begin() + ABG.size());
-        Packet = DeComp(Packet);
+        try {
+            Packet = DeComp(Packet);
+        } catch (const InvalidDataError& ) {
+            auto LockedClient = Client.lock();
+            beammp_errorf("Failed to decompress packet from client {}. The client sent invalid data and will now be disconnected.", LockedClient->GetID());
+            Network.ClientKick(*LockedClient, "Sent invalid compressed packet (this is likely a bug on your end)");
+            return;
+        } catch (const std::runtime_error& e) {
+            auto LockedClient = Client.lock();
+            beammp_errorf("Failed to decompress packet from client {}: {}. The server might be out of RAM! The client will now be disconnected.", LockedClient->GetID(), e.what());
+            Network.ClientKick(*LockedClient, "Decompression failed (likely a server-side problem)");
+            return;
+        }
     }
     if (Packet.empty()) {
         return;