1438263 - Unexpected TLS alerts should abort connections

Status: NEW

(NSS :: Libraries, enhancement, P3)

Description

[J.C. Jones [:jcj] (he/they)]

The new BoGo test SendBogusAlertType sends an alert of type 0x42 [1] and expects the server to abort the connection with :UNKNOWN_ALERT_TYPE:. NSS ignores this and the connection succeeds.

We should abort as well.

[1] https://github.com/google/boringssl/blob/67968895b3b8cace34ea6dbdf65ac922667959ac/ssl/test/runner/runner.go#L841

Comment 1

[Tim Taubert [:ttaubert] (inactive)]

Confirming, per spec:

"All alerts defined in this section below, as well as all unknown alerts, are universally considered fatal as of TLS 1.3 (see Section 6)."

Comment 2

[Daniel Veditz [:dveditz]]

Does this need to be hidden to protect our users? Or is it just a correctness bug?

Comment 3

[Martin Thomson [:mt:]]

JC, if this is an authenticated alert, then there isn't any reason for this to be marked sensitive.  Or is this sent in the clear?

Comment 4

[J.C. Jones [:jcj] (he/they)]

(In reply to Martin Thomson [:mt:] from comment #3)
> JC, if this is an authenticated alert, then there isn't any reason for this
> to be marked sensitive.  Or is this sent in the clear?

Yes, it appears that BoGo is sending this as an authenticated alert [1] [2], so I agree, let's open this up.

[1] https://github.com/google/boringssl/blob/78a832d793bb6c097bf443f3c85d6a1ee4240764/ssl/test/runner/runner.go#L841
[2] https://golang.org/src/crypto/tls/conn.go line 718, 852