Re: [Qemu-devel] [PATCH v4 2/7] crypto: introduce new module for TLS anonymous credentials

["Daniel P. Berrange" <berrange@redhat.com>]

On Mon, Aug 24, 2015 at 02:46:30PM -0600, Eric Blake wrote:
> On 08/24/2015 08:14 AM, Daniel P. Berrange wrote:
> > Introduce a QCryptoTLSCredsAnon class which is used to
> > manage anonymous TLS credentials. Use of this class is
> > generally discouraged since it does not offer strong
> > security, but it is required for backwards compatibility
> > with the current VNC server implementation.
> > 
> > Simple example CLI configuration:
> > 
> >  $QEMU -object tls-creds-anon,id=tls0,endpoint=server
> > 
> > Example using pre-created diffie-hellman parameters
> > 
> >  $QEMU -object tls-creds-anon,id=tls0,endpoint=server,\
> >                dir=/path/to/creds/dir
> > 
> > The 'id' value in the -object args will be used to associate the
> > credentials with the network services. For eample, when the VNC
> 
> s/eample/example/
> 
> > server is later converted it would use
> > 
> >  $QEMU -object tls-creds-anon,id=tls0,.... \
> >        -vnc 127.0.0.1:1,tls-creds=tls0
> > 
> > Signed-off-by: Daniel P. Berrange <berrange@redhat.com>
> > ---
> 
> > +++ b/crypto/init.c
> > @@ -20,6 +20,7 @@
> >  
> >  #include "crypto/init.h"
> >  #include "crypto/tlscreds.h"
> > +#include "crypto/tlscredsanon.h"
> >  #include "qemu/thread.h"
> >  
> >  #ifdef CONFIG_GNUTLS
> > @@ -144,6 +145,7 @@ int qcrypto_init(Error **errp)
> >       * clever enough to see the constructor :-(
> >       */
> >      qcrypto_tls_creds_dummy();
> > +    qcrypto_tls_creds_anon_dummy();
> 
> Are there any gcc hacks such as adding __attribute__((used)) that might
> help?

I finally figured out that we can use  -Wl,--whole-archive when
linking to libqemuutil.a to fix this properly.


Regards,
Daniel
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