Merge pull request #326 from Phlogi/fix-packet-error-partial-read

Fix partial socket reads causing ‘Failed reading packet’ errors

Author: kokarare1212

librespot/core.py

@@ -1932,6 +1932,20 @@ def read(self, length: int) -> bytes:
             """
             return self.__socket.recv(length)
 
+        def read_exact(self, length: int) -> bytes:
+            """Read exactly length bytes from socket or raise on EOF."""
+            if length == 0:
+                return b""
+            buffer = bytearray()
+            remaining = length
+            while remaining > 0:
+                chunk = self.__socket.recv(remaining)
+                if chunk == b"":
+                    raise ConnectionError("EOF")
+                buffer.extend(chunk)
+                remaining -= len(chunk)
+            return bytes(buffer)
+
         def read_int(self) -> int:
             """Read integer from socket
 
@@ -2042,7 +2056,8 @@ def run(self) -> None:
                             format(util.bytes_to_hex(packet.cmd),
                                    packet.payload))
                         continue
-                except (RuntimeError, ConnectionResetError) as ex:
+                except (RuntimeError, ConnectionResetError,
+                        ConnectionError) as ex:
                     if self.__running:
                         self.__session.logger.fatal(
                             "Failed reading packet! {}".format(ex))

librespot/crypto.py

@@ -55,16 +55,19 @@ def receive_encoded(self, connection: Session.ConnectionHolder) -> Packet:
         try:
             self.__receive_cipher.nonce(self.__receive_nonce)
             self.__receive_nonce += 1
-            header_bytes = self.__receive_cipher.decrypt(connection.read(3))
+            header_bytes = self.__receive_cipher.decrypt(
+                connection.read_exact(3))
             cmd = struct.pack(">s", bytes([header_bytes[0]]))
             payload_length = (header_bytes[1] << 8) | (header_bytes[2] & 0xff)
             payload_bytes = self.__receive_cipher.decrypt(
-                connection.read(payload_length))
-            mac = connection.read(4)
+                connection.read_exact(payload_length))
+            mac = connection.read_exact(4)
             expected_mac = self.__receive_cipher.finish(4)
             if mac != expected_mac:
-                raise RuntimeError()
+                raise RuntimeError("Bad MAC")
             return Packet(cmd, payload_bytes)
+        except ConnectionError:
+            raise
         except (IndexError, OSError):
             raise RuntimeError("Failed to receive packet")