Not honoring D.4. Middlebox Compatibility Mode

WernerWenz commented 5 years ago

As per RFC an arbitrary number of (empty, unencrypted) change_cipher_spec records may be send during the handshake. Most clients will most likeley use this feature in order to increase chances for successfully establishing a TLS connection over the Internet. OpenSSL s_client and TLS-tris for example do so and thus currently are not compatible.

Fixing might be possible at https://github.com/bifurcation/mint/blob/83ba9bc2ead9cdf8b0c8bd94e8a41243e5f6ed88/record-layer.go#L383

However, while enabling connections from OpenSSL/tris, a simple

func (r *DefaultRecordLayer) nextRecord(allowOldEpoch bool) (*TLSPlaintext, error) {
again:
....
case RecordTypeChangeCipherSpec:
   goto again

would not be sufficient as these records must only occur unencrypted during the handshake (before the client finished).

bifurcation commented 5 years ago

@ekr - Is this is a spec compliance issue or a feature request?

ekr commented 5 years ago

Assuming i am reading the report correctly, it's spec compliance. I think it's probably in one of the existing PRs though

On Mon, Feb 11, 2019 at 2:03 PM Richard Barnes notifications@github.com wrote:

@ekr https://github.com/ekr - Is this is a spec compliance issue or a feature request?

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bifurcation / mint

Not honoring D.4. Middlebox Compatibility Mode #200