Bug#710657: gnutls: Negiotates an SSL v3.0 cipher when talkign to openssl using TLS 1.2

[Kurt Roeckx]

Source: gnutls26
Version: 2.12.20-6
Severity: important
Tags: security

Hi,

When using gnutls-cli to talk to apache with mod_ssl, I
always get this when testing with SSL v3.0 to TLS v1.2:
- Key Exchange: DHE-RSA
- Cipher: AES-128-CBC
- MAC: SHA1

When talking to it with TLS 1.2, I really would like to see
that it doesn't use SHA1.  From gnutls-cli --list, I would
expect it to use one of the following:
TLS_DHE_RSA_AES_128_CBC_SHA256                          0x00, 0x67 TLS1.2
TLS_DHE_RSA_AES_256_CBC_SHA256                          0x00, 0x6b TLS1.2

Openssl supports both of them.

openssl also selects DHE-RSA-AES256-SHA256 when talking to itself
when GCM is disabled, so I assume this is a gnutls problem.


Kurt