Thread: Certificate, login & php question ?

On Mon, Sep 11, 2006 at 02:32:26AM +0200, Jean-Gerard Pailloncy wrote:
> I have setup an apache server with SSL.
> I create a CA, serker.key, server.crt.
> I create a user.key and user.cert.
> Now the apache server accept only the correct certificate for login
> on a given directory.
>
> I have a PHP script that query the database using the HTTP login/
> password as PostgreSQL user/password.
>
> I plan to add the same SSL setup to PostreSQL.
> 1) Is it possible to use the SSL authentification done by apache with
> PostgreSQL ?

I don't think so.  If the PHP script makes an SSL connection to
PostgreSQL and PostgreSQL requests a client certificate, then the
PHP script will need access to a private key to respond correctly.
The HTTP client's private key won't be available to Apache/PHP (at
least not via the HTTP connection) so the script will need to use
a private key of its own.  I'm not aware of a way for Apache to
proxy PostgreSQL's SSL negotiation with the PHP script back to the
HTTP client.

> 2) How the DN of the certificate is match against an PostgreSQL role ?

As far as I can tell no such matching is done.  I can make SSL
connections to PostgreSQL as any user with the same certificate,
and I don't see anything in the documentation that allows that to
be configured.  If I've overlooked something then somebody please
point it out.

--
Michael Fuhr

On Sun, Sep 10, 2006 at 09:39:59PM -0600, Michael Fuhr wrote:
> On Mon, Sep 11, 2006 at 02:32:26AM +0200, Jean-Gerard Pailloncy wrote:
> > 1) Is it possible to use the SSL authentification done by apache with
> > PostgreSQL ?
>
> I'm not aware of a way for Apache to proxy PostgreSQL's SSL
> negotiation with the PHP script back to the HTTP client.

If such a capability existed then it could arguably be considered
a flaw in SSL because it would allow a server to impersonate one
of its clients to another server or to hijack a client's secure
connection with another server.  Secure protocols are designed to
prevent such attacks.

--
Michael Fuhr

On Mon, Sep 11, 2006 at 10:44:18AM +0200, Jean-Gerard Pailloncy wrote:
> Le 11 sept. 06 à 05:57, Michael Fuhr a écrit :
> > If such a capability existed then it could arguably be considered
> > a flaw in SSL because it would allow a server to impersonate one
> > of its clients to another server or to hijack a client's secure
> > connection with another server.  Secure protocols are designed to
> > prevent such attacks.
>
> The point is to USE AGAIN the authentification done by Apache with
> PostgreSQL not DO AGAIN the authentification.

To "use again" the client's authentication you'd have to "do again"
the authentication.  If the PHP script makes an SSL connection to
PostgreSQL then that connection is independent of the HTTP client's
SSL connection with the web server.  If the server in the new
connection (PostgreSQL) sends an SSL CertificateRequest message
then the client (the PHP script) needs access to a certificate and
the corresponding private key to reply with Certificate and
CertificateVerify messages.  The HTTP client's certificate would
be available but that client's private key would not, so the PHP
script would have no way to build a valid CertificateVerify message.

> Googling around, I found:
> mod_auth_krb with "AuthType KerberosV5SaveCredentials"
> The auth is done by mod_auth_krb and mod_perl is able to use the same
> ticket for PostgreSQL. It is in the doc of PG.

You didn't mention Kerberos before; you said you wanted to reuse
the client's SSL authentication.  Kerberos works differently than
SSL; I'd have to research the links you mentioned to see if reusing
the client's credientials would indeed be possible using Kerberos.

--
Michael Fuhr