Re: [TLS] Another ClientHello length intolerance bug?

2018-09-12 Thread David A. Cooper
It would be unlikely to hit this bug in practice. I just tried a test with Chromium 65. In the default configuration, with a 9-byte server name, the TLSCiphertext.length was 192 bytes. So, in order to hit the bug it would seem that the server's DNS name would have

Re: [TLS] Another ClientHello length intolerance bug?

2018-09-12 Thread David Benjamin
Wow! That's a bizarre one. I don't think we've run into this one before, but, from your description, any given implementation would only have a 1/256 chance of hitting it on every ClientHello change. 10 is a newline, so perhaps some implementation is doing a terrible job detecting TLS vs. some pla

[TLS] Another ClientHello length intolerance bug?

2018-09-12 Thread David A. Cooper
According to RFC 7685 there was at least one TLS implementation that would hang the connection if it received a ClientHello record with a TLSCiphertext.length between 256 and 511 bytes. During some recent testing I believe that I have come across a similar length int