Merge pull request #166 from kpreisser/fixDecodeRemainingLength

Fix the algorithm for decoding the body length
This commit is contained in:
Christian
2018-01-24 20:09:14 +01:00
committed by GitHub
@@ -86,7 +86,7 @@ namespace MQTTnet.Serializer
private static async Task<int> ReadBodyLengthFromSourceAsync(Stream stream, CancellationToken cancellationToken)
{
// Alorithm taken from http://docs.oasis-open.org/mqtt/mqtt/v3.1.1/os/mqtt-v3.1.1-os.html.
// Alorithm taken from https://docs.oasis-open.org/mqtt/mqtt/v3.1.1/errata01/os/mqtt-v3.1.1-errata01-os-complete.html.
var multiplier = 1;
var value = 0;
byte encodedByte;
@@ -110,11 +110,11 @@ namespace MQTTnet.Serializer
readBytes.Add(encodedByte);
value += (byte)(encodedByte & 127) * multiplier;
multiplier *= 128;
if (multiplier > 128 * 128 * 128)
{
throw new MqttProtocolViolationException($"Remaining length is invalid (Data={string.Join(",", readBytes)}).");
}
multiplier *= 128;
} while ((encodedByte & 128) != 0);
return value;