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I'm trying to configure my Debian box with mod_gnutls implementation (for sake of SNI), to achieve best possible results in TLSv1.0/1.1/1.2 (disregarding both SSL2 and SSL3)

However it seems to me, that it's not possible to use ECDHE-ECDSA/ECDHE-RSA in mod_gnutls, when it is possible with gnutls-cli

+ECDHE-RSA:+ECDHE-ECDSA in GnuTLSPriorities triggers error Syntax error parsing priorities string at ...

My current configuration line:

GnuTLSPriorities    NONE:+SHA512:+SHA384:+SHA256:+DHE-RSA:+DHE-PSK:
                    +DHE-DSS:+AES-256-CBC:+AES-128-CBC:+3DES-CBC:+VERS-TLS1.2:
                    +VERS-TLS1.1:+VERS-TLS1.0:+COMP-NULL:+SHA1:+SIGN-ALL

Where output of nmap

> nmap --script ssl-enum-ciphers -p 443 www.mydomain.tld

Starting Nmap 6.47 ( http://nmap.org ) at 2014-10-27 00:55 CET
Nmap scan report for www.mydomain.tld (46.249.37.143)
Host is up (0.046s latency).
rDNS record for 46.249.37.143: lampicka.cz
PORT    STATE SERVICE
443/tcp open  https
| ssl-enum-ciphers: 
|   TLSv1.0: 
|     ciphers: 
|       TLS_DHE_RSA_WITH_3DES_EDE_CBC_SHA - strong
|       TLS_DHE_RSA_WITH_AES_128_CBC_SHA - strong
|       TLS_DHE_RSA_WITH_AES_256_CBC_SHA - strong
|     compressors: 
|       NULL
|   TLSv1.1: 
|     ciphers: 
|       TLS_DHE_RSA_WITH_3DES_EDE_CBC_SHA - strong
|       TLS_DHE_RSA_WITH_AES_128_CBC_SHA - strong
|       TLS_DHE_RSA_WITH_AES_256_CBC_SHA - strong
|     compressors: 
|       NULL
|   TLSv1.2: 
|     ciphers: 
|       TLS_DHE_RSA_WITH_3DES_EDE_CBC_SHA - strong
|       TLS_DHE_RSA_WITH_AES_128_CBC_SHA - strong
|       TLS_DHE_RSA_WITH_AES_128_CBC_SHA256 - strong
|       TLS_DHE_RSA_WITH_AES_256_CBC_SHA - strong
|       TLS_DHE_RSA_WITH_AES_256_CBC_SHA256 - strong
|     compressors: 
|       NULL

And output of gnutls-cli, when given additional config +ECDHE-RSA:+ECDHE-ECDSA

> gnutls-cli -l --priority "NONE:+SHA512:+SHA384:+SHA256:+DHE-RSA:+DHE-PSK:+DHE-DSS:+AES-256-CBC:+AES-128-CBC:+3DES-CBC:+VERS-TLS1.2:+VERS-TLS1.1:+VERS-TLS1.0:+COMP-NULL:+SHA1:+SIGN-ALL:+ECDHE-RSA:+ECDHE-ECDSA"
Cipher suites for NONE:+SHA512:+SHA384:+SHA256:+DHE-RSA:+DHE-PSK:+DHE-DSS:+AES-256-CBC:+AES-128-CBC:+3DES-CBC:+VERS-TLS1.2:+VERS-TLS1.1:+VERS-TLS1.0:+COMP-NULL:+SHA1:+SIGN-ALL:+ECDHE-RSA:+ECDHE-ECDSA
TLS_DHE_RSA_AES_256_CBC_SHA256                          0x00, 0x6b      TLS1.0
TLS_DHE_RSA_AES_256_CBC_SHA1                            0x00, 0x39      SSL3.0
TLS_DHE_RSA_AES_128_CBC_SHA256                          0x00, 0x67      TLS1.0
TLS_DHE_RSA_AES_128_CBC_SHA1                            0x00, 0x33      SSL3.0
TLS_DHE_RSA_3DES_EDE_CBC_SHA1                           0x00, 0x16      SSL3.0
TLS_DHE_PSK_AES_256_CBC_SHA384                          0x00, 0xb3      TLS1.0
TLS_DHE_PSK_AES_256_CBC_SHA1                            0x00, 0x91      SSL3.0
TLS_DHE_PSK_AES_128_CBC_SHA256                          0x00, 0xb2      TLS1.0
TLS_DHE_PSK_AES_128_CBC_SHA1                            0x00, 0x90      SSL3.0
TLS_DHE_PSK_3DES_EDE_CBC_SHA1                           0x00, 0x8f      SSL3.0
TLS_DHE_DSS_AES_256_CBC_SHA256                          0x00, 0x6a      TLS1.0
TLS_DHE_DSS_AES_256_CBC_SHA1                            0x00, 0x38      SSL3.0
TLS_DHE_DSS_AES_128_CBC_SHA256                          0x00, 0x40      TLS1.0
TLS_DHE_DSS_AES_128_CBC_SHA1                            0x00, 0x32      SSL3.0
TLS_DHE_DSS_3DES_EDE_CBC_SHA1                           0x00, 0x13      SSL3.0
TLS_ECDHE_RSA_AES_256_CBC_SHA384                        0xc0, 0x28      TLS1.0
TLS_ECDHE_RSA_AES_256_CBC_SHA1                          0xc0, 0x14      SSL3.0
TLS_ECDHE_RSA_AES_128_CBC_SHA256                        0xc0, 0x27      TLS1.0
TLS_ECDHE_RSA_AES_128_CBC_SHA1                          0xc0, 0x13      SSL3.0
TLS_ECDHE_RSA_3DES_EDE_CBC_SHA1                         0xc0, 0x12      SSL3.0
TLS_ECDHE_ECDSA_AES_256_CBC_SHA384                      0xc0, 0x24      TLS1.0
TLS_ECDHE_ECDSA_AES_256_CBC_SHA1                        0xc0, 0x0a      SSL3.0
TLS_ECDHE_ECDSA_AES_128_CBC_SHA256                      0xc0, 0x23      TLS1.0
TLS_ECDHE_ECDSA_AES_128_CBC_SHA1                        0xc0, 0x09      SSL3.0
TLS_ECDHE_ECDSA_3DES_EDE_CBC_SHA1                       0xc0, 0x08      SSL3.0

Certificate types: none
Protocols: VERS-TLS1.2, VERS-TLS1.1, VERS-TLS1.0
Compression: COMP-NULL
Elliptic curves: none
PK-signatures: SIGN-RSA-SHA256, SIGN-DSA-SHA256, SIGN-ECDSA-SHA256, SIGN-RSA-SHA384, SIGN-ECDSA-SHA384, SIGN-RSA-SHA512, SIGN-ECDSA-SHA512, SIGN-RSA-SHA224, SIGN-DSA-SHA224, SIGN-ECDSA-SHA224, SIGN-RSA-SHA1, SIGN-DSA-SHA1, SIGN-ECDSA-SHA1

My software versions are:

  • libapache2-mod-gnutls
    • 0.5.10-1.1
  • apache2
    • 2.2.22-13+deb7u3
  • gnutls-bin
    • 3.3.8-3

1 Answer 1

1

Well, it turns out that the problem is in libapache2-mod-gnutls version.

Version 0.5.X is linked with libgnutls26, which doesn't contain those ciphers
Version 0.6.X is linked with libgnutls28, which contains ECDHE-RSA/ECDHE-ECDSA

So the solutions are two:

  • Upgrade to newer version of libapache2-mod-gnutls, which requires Apache 2.4
  • Use OpenSSL contained in Apache 2.2 version, and configure it appropriately

Valid configuration for libapache2-mod-gnutls is:

GnuTLSPriorities    NONE:+SHA512:+SHA384:+SHA256:+ECDHE-RSA:+ECDHE-ECDSA:+DHE-RSA:+DHE-PSK:
                    +DHE-DSS:+AES-256-CBC:+AES-128-CBC:+3DES-CBC:+VERS-TLS1.2:
                    +VERS-TLS1.1:+VERS-TLS1.0:+COMP-NULL:+SHA1:+SIGN-ALL

Valid configiuration for apache2 (openssl) is:

SSLCipherSuite ECDHE-ECDSA-AES256-SHA:ECDHE-ECDSA-AES128-GCM-SHA256:ECDHE-RSA-AES128-SHA256:DHE-RSA-AES128-SHA:RC4-RSA:HIGH:!MD5:!aNULL
SSLHonorCipherOrder     on
SSLCompression          off
SSLProtocol all -SSLv2 -SSLv3
Header add Strict-Transport-Security "max-age=15768000"

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