Re: ioemu: empty vnc passwd

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

On Wed, Jan 23, 2008 at 04:11:30PM +0000, Samuel Thibault wrote:
> Hello,
> 
> There is a small bug in xenstore.c: the following patch is needed
> because else xenstore_read_vncpasswd would return 0 even when it is
> unable to read the passwd.
> 
> diff -r 9e92672385a5 tools/ioemu/xenstore.c
> --- a/tools/ioemu/xenstore.c	Wed Jan 23 13:37:03 2008 +0000
> +++ b/tools/ioemu/xenstore.c	Wed Jan 23 15:53:01 2008 +0000
> @@ -518,7 +518,7 @@ int xenstore_read_vncpasswd(int domid, c
>          pwbuf[0] = '\0';
>          free(uuid);
>          free(path);
> -        return rc;
> +        return -1;
>      }
>  
>      for (i=0; i<len && i<pwbuflen; i++) {
> 
> However, that means we can't use an empty passwd any more, while that
> may be quite useful e.g. in testing environments, so that we would need
> the following patch:

This is handled in XenD.

  - If a non-empty passwd is found in the guest config, or in the
    global XenD config,, then qemu has  -vnc :1,passwd  on its CLI
    to turn on password auth.
  - If there is no guest password and no global XenD password,
    then   qemu has  -vnc :1   and no password auth is enabled
    at all.

If you were to turn on password auth, and the password is a zero
length string, then all clients would be rejected, because the QEMU
VNC server explicitly fails password auth for "". This shouldn't
occur, because XenD should't have turned on password auth in the
first place if the guest password was ""

Regards,
Dan.
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