i2p: limit the size of incoming messages

Put a limit on the amount of data `Sock::RecvUntilTerminator()` can read
if no terminator is received.

In the case of I2P this avoids a runaway (or malicious) I2P proxy
sending us tons of data without a terminator before a timeout is
triggered.

1 files changed, 4 insertions, 1 deletions

diff --git a/src/util/sock.h b/src/util/sock.h
index ecebb84205..4b0618dcff 100644
--- a/src/util/sock.h
+++ b/src/util/sock.h
@@ -135,13 +135,16 @@ public:
      * @param[in] terminator Character up to which to read from the socket.
      * @param[in] timeout Timeout for the entire operation.
      * @param[in] interrupt If this is signaled then the operation is canceled.
+     * @param[in] max_data The maximum amount of data (in bytes) to receive. If this many bytes
+     * are received and there is still no terminator, then this method will throw an exception.
      * @return The data that has been read, without the terminating character.
      * @throws std::runtime_error if the operation cannot be completed. In this case some bytes may
      * have been consumed from the socket.
      */
     virtual std::string RecvUntilTerminator(uint8_t terminator,
                                             std::chrono::milliseconds timeout,
-                                            CThreadInterrupt& interrupt) const;
+                                            CThreadInterrupt& interrupt,
+                                            size_t max_data) const;
 
     /**
      * Check if still connected.