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Sender: Paolo Bonzini <paolo.bonzini@gmail.com>
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Date: Wed, 11 Dec 2013 17:06:54 +0100
From: Paolo Bonzini <pbonzini@redhat.com>
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Subject: Re: [Qemu-devel] [PATCH] vnc: refuse to set a password with
	VNC_AUTH_NONE
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To: Gerd Hoffmann <kraxel@redhat.com>
Cc: qemu-devel@nongnu.org, Anthony Liguori <aliguori@amazon.com>

Il 11/12/2013 16:54, Gerd Hoffmann ha scritto:
> Current code silently changes the authentication settings
> in case you try to set a password without password authentication
> turned on.  This is bad.  Return an error instead.
> 
> If we want allow changing auth settings at runtime this should
> be done explicitly using a separate monitor command, not as
> side effect of set_passwd.
> 
> Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>

Isn't this backwards-incompatible?

Paolo

> ---
>  ui/vnc.c | 34 ++++++----------------------------
>  1 file changed, 6 insertions(+), 28 deletions(-)
> 
> diff --git a/ui/vnc.c b/ui/vnc.c
> index 5601cc3..79efb80 100644
> --- a/ui/vnc.c
> +++ b/ui/vnc.c
> @@ -2971,26 +2971,6 @@ static void vnc_display_close(DisplayState *ds)
>  #endif
>  }
>  
> -static int vnc_display_disable_login(DisplayState *ds)
> -{
> -    VncDisplay *vs = vnc_display;
> -
> -    if (!vs) {
> -        return -1;
> -    }
> -
> -    if (vs->password) {
> -        g_free(vs->password);
> -    }
> -
> -    vs->password = NULL;
> -    if (vs->auth == VNC_AUTH_NONE) {
> -        vs->auth = VNC_AUTH_VNC;
> -    }
> -
> -    return 0;
> -}
> -
>  int vnc_display_password(DisplayState *ds, const char *password)
>  {
>      VncDisplay *vs = vnc_display;
> @@ -2998,20 +2978,18 @@ int vnc_display_password(DisplayState *ds, const char *password)
>      if (!vs) {
>          return -EINVAL;
>      }
> -
> -    if (!password) {
> -        /* This is not the intention of this interface but err on the side
> -           of being safe */
> -        return vnc_display_disable_login(ds);
> +    if (vs->auth == VNC_AUTH_NONE) {
> +        error_printf_unless_qmp("If you want use passwords please enable "
> +                                "password auth using '-vnc ${dpy},password'.");
> +        return -EINVAL;
>      }
>  
>      if (vs->password) {
>          g_free(vs->password);
>          vs->password = NULL;
>      }
> -    vs->password = g_strdup(password);
> -    if (vs->auth == VNC_AUTH_NONE) {
> -        vs->auth = VNC_AUTH_VNC;
> +    if (password) {
> +        vs->password = g_strdup(password);
>      }
>  
>      return 0;
>