[PATCH] Add TLS-SRP (RFC 5054) support to mod_ssl

[Quinn Slack <sq...@cs.stanford.edu>]

Posted at: https://issues.apache.org/bugzilla/show_bug.cgi?id=51075

TLS-SRP (RFC 5054)[1] is an implementation of the Secure Remote Password
(SRP)[2] protocol as a key exchange method for TLS. It uses a shared secret
derived from a user's password to supplement or replace third-party
certificates in authenticating a TLS connection.

This patch adds TLS-SRP support to mod_ssl, adds two new directives
(SSLSRPVerifierFile and SSLSRPUnknownUserSeed), adds two new SSL env vars
(SSL_SRP_USER and SSL_SRP_USERINFO), and includes basic documentation.

The TLS-SRP-specific code uses preprocessor guards on OPENSSL_NO_SRP and is
enabled only if OpenSSL >= 1.0.1, which is the first version of OpenSSL that
will include SRP support[3].

To use this patch:
(1) install OpenSSL 1.0.1;
(2) create an OpenSSL SRP verifier (passwd) file with `openssl srp -srpvfile
passwd.srpv -add username`;
(3) specify this file in the server config with: SSLSRPVerifierFile
/path/to/passwd.srpv
(4) optionally, for easier testing, force the use of SRP: SSLCipherSuite
"!DSS:!aRSA:SRP"

To test the TLS-SRP functionality, use gnutls-cli or a version of cURL with
TLS-SRP support:

gnutls-cli --srpusername user --srppasswd secret host
curl --tlsuser user --tlspassword secret -k https://host

TLS-SRP support for Apache is already provided by mod_gnutls[4]. Now that PAKE
patents have expired and the security of CAs is increasingly being doubted,
TLS-SRP is gaining wider acceptance. GnuTLS, mod_gnutls, and TLSLite have
supported it for years; cURL since February; OpenSSL will support it in the
next release; and I have also assembled patches[5] for Chrome, Firefox, and
NSS.

This patch was originally created by Christophe Renou and Peter Sylvester of
EdelWeb. I updated it to work with Apache 2's mod_ssl.

Bugzilla entry: https://issues.apache.org/bugzilla/show_bug.cgi?id=51075
Patch: https://issues.apache.org/bugzilla/attachment.cgi?id=26892


[1] http://tools.ietf.org/html/rfc5054
[2] http://srp.stanford.edu/
[3] http://cvs.openssl.org/chngview?cn=20484
[4] http://trustedhttp.org/wiki/TLS-SRP_in_Apache_mod_gnutls
[5] http://trustedhttp.org/

Re: [PATCH] Add TLS-SRP (RFC 5054) support to mod_ssl

[Andrew Oliver <ac...@gmail.com>]

This is excellent news!
On Apr 17, 2011 5:48 PM, "Quinn Slack" <sq...@cs.stanford.edu> wrote:
> Posted at: https://issues.apache.org/bugzilla/show_bug.cgi?id=51075
>
> TLS-SRP (RFC 5054)[1] is an implementation of the Secure Remote Password
> (SRP)[2] protocol as a key exchange method for TLS. It uses a shared
secret
> derived from a user's password to supplement or replace third-party
> certificates in authenticating a TLS connection.
>
> This patch adds TLS-SRP support to mod_ssl, adds two new directives
> (SSLSRPVerifierFile and SSLSRPUnknownUserSeed), adds two new SSL env vars
> (SSL_SRP_USER and SSL_SRP_USERINFO), and includes basic documentation.
>
> The TLS-SRP-specific code uses preprocessor guards on OPENSSL_NO_SRP and
is
> enabled only if OpenSSL >= 1.0.1, which is the first version of OpenSSL
that
> will include SRP support[3].
>
> To use this patch:
> (1) install OpenSSL 1.0.1;
> (2) create an OpenSSL SRP verifier (passwd) file with `openssl srp
-srpvfile
> passwd.srpv -add username`;
> (3) specify this file in the server config with: SSLSRPVerifierFile
> /path/to/passwd.srpv
> (4) optionally, for easier testing, force the use of SRP: SSLCipherSuite
> "!DSS:!aRSA:SRP"
>
> To test the TLS-SRP functionality, use gnutls-cli or a version of cURL
with
> TLS-SRP support:
>
> gnutls-cli --srpusername user --srppasswd secret host
> curl --tlsuser user --tlspassword secret -k https://host
>
> TLS-SRP support for Apache is already provided by mod_gnutls[4]. Now that
PAKE
> patents have expired and the security of CAs is increasingly being
doubted,
> TLS-SRP is gaining wider acceptance. GnuTLS, mod_gnutls, and TLSLite have
> supported it for years; cURL since February; OpenSSL will support it in
the
> next release; and I have also assembled patches[5] for Chrome, Firefox,
and
> NSS.
>
> This patch was originally created by Christophe Renou and Peter Sylvester
of
> EdelWeb. I updated it to work with Apache 2's mod_ssl.
>
> Bugzilla entry: https://issues.apache.org/bugzilla/show_bug.cgi?id=51075
> Patch: https://issues.apache.org/bugzilla/attachment.cgi?id=26892
>
>
> [1] http://tools.ietf.org/html/rfc5054
> [2] http://srp.stanford.edu/
> [3] http://cvs.openssl.org/chngview?cn=20484
> [4] http://trustedhttp.org/wiki/TLS-SRP_in_Apache_mod_gnutls
> [5] http://trustedhttp.org/