Re: [Qemu-devel] [PATCH] support for unsetting the VNC password from the monitor.

Re: [Qemu-devel] [PATCH] support for unsetting the VNC password from the monitor.

[Nolan]

Anthony wrote:
> Nolan wrote:
> > Add monitor support for setting the VNC password to "", disabling VNC.
> > 
> > The magic sentinel value is "<<unset>>" which is not a valid VNC
> > password by virtue of being 9 characters long.
> 
> That's a little too magical for me. If you want to disable VNC, can't
> you just say change vnc none?

If you start with "-vnc :0,password", you will have no password set
(thus logins are disabled), but qemu is listening on the port (keeping
it occupied).

"vnc change none" will close the socket.  The intent of "change vnc
password <<unset>>" is to leave the socket open, but disallow logins
until the password is reset.  Basically the goal is to provide a way to
get back into state we were in immediately after process start.  This is
currently possible with the interactive "change vnc password" command,
but not possible with the non-interactive variant.

Re: [Qemu-devel] [PATCH] support for unsetting the VNC password from the monitor.

[Daniel P. Berrange]

On Thu, Mar 05, 2009 at 03:18:41PM -0800, Nolan wrote:
> Anthony wrote:
> > Nolan wrote:
> > > Add monitor support for setting the VNC password to "", disabling VNC.
> > > 
> > > The magic sentinel value is "<<unset>>" which is not a valid VNC
> > > password by virtue of being 9 characters long.
> > 
> > That's a little too magical for me. If you want to disable VNC, can't
> > you just say change vnc none?
> 
> If you start with "-vnc :0,password", you will have no password set
> (thus logins are disabled), but qemu is listening on the port (keeping
> it occupied).
> 
> "vnc change none" will close the socket.  The intent of "change vnc
> password <<unset>>" is to leave the socket open, but disallow logins
> until the password is reset.  Basically the goal is to provide a way to
> get back into state we were in immediately after process start.  This is
> currently possible with the interactive "change vnc password" command,
> but not possible with the non-interactive variant.

How about just making it parse quotes for the password, so you could
do 

  change vnc password ""

and thus have it set to the empty string. This would also let people have
passwords with spaces in them

Daniel
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Re: [Qemu-devel] [PATCH] support for unsetting the VNC password from the monitor.

[Nolan]

Daniel wrote:
> How about just making it parse quotes for the password, so you could
> do 
> 
>   change vnc password ""
> 
> and thus have it set to the empty string. This would also let people
> have passwords with spaces in them

An excellent suggestion.  So excellent in fact, that it already works
with qemu as is.

I rescind my request to apply this patch.  Either quotes being parsed by
the monitor is a relatively new phenomenon, or I spaced pretty badly
when I wrote this last summer.

Re: [Qemu-devel] [PATCH] support for unsetting the VNC password from the monitor.

[Daniel P. Berrange]

On Fri, Mar 06, 2009 at 02:34:18PM -0800, Nolan wrote:
> Daniel wrote:
> > How about just making it parse quotes for the password, so you could
> > do 
> > 
> >   change vnc password ""
> > 
> > and thus have it set to the empty string. This would also let people
> > have passwords with spaces in them
> 
> An excellent suggestion.  So excellent in fact, that it already works
> with qemu as is.

I aim to please :-)

> I rescind my request to apply this patch.  Either quotes being parsed by
> the monitor is a relatively new phenomenon, or I spaced pretty badly
> when I wrote this last summer.

This was news to me too! It is probably worth mentioning this explicitly
in the qemu-doc.texi  documentation file on the 'change vnc passwd' 
command, if you wish to provide a patch to that.

Regards,
Daniel
-- 
|: Red Hat, Engineering, London   -o-   http://people.redhat.com/berrange/ :|
|: http://libvirt.org  -o-  http://virt-manager.org  -o-  http://ovirt.org :|
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[Qemu-devel] [PATCH] support for unsetting the VNC password from the monitor.

[Nolan]

Add monitor support for setting the VNC password to "", disabling VNC.

The magic sentinel value is "<<unset>>" which is not a valid VNC password by
virtue of being 9 characters long.

diff --git a/qemu/monitor.c b/qemu/monitor.c
index 1b2adc8..7bbb457 100644
--- a/qemu/monitor.c
+++ b/qemu/monitor.c
@@ -466,8 +466,13 @@ static void do_change_vnc(const char *target, const char *arg)
 	strcmp(target, "password") == 0) {
 	char password[9];
 	if (arg) {
-	    strncpy(password, arg, sizeof(password));
-	    password[sizeof(password) - 1] = '\0';
+            /* "<<unset>>" is 9 chars long, so it is not a valid VNC passwd. */
+            if (strcmp(arg, "<<unset>>") == 0) {
+                password[0] = '\0';
+            } else {
+                strncpy(password, arg, sizeof(password));
+                password[sizeof(password) - 1] = '\0';
+            }
 	} else
 	    monitor_readline("Password: ", 1, password, sizeof(password));
 	if (vnc_display_password(NULL, password) < 0)

Re: [Qemu-devel] [PATCH] support for unsetting the VNC password from the monitor.

[Anthony Liguori]

Nolan wrote:
> Add monitor support for setting the VNC password to "", disabling VNC.
>
> The magic sentinel value is "<<unset>>" which is not a valid VNC password by
> virtue of being 9 characters long.
>   

That's a little too magical for me.  If you want to disable VNC, can't 
you just say change vnc none?

Regards,

Anthony Liguori

> diff --git a/qemu/monitor.c b/qemu/monitor.c
> index 1b2adc8..7bbb457 100644
> --- a/qemu/monitor.c
> +++ b/qemu/monitor.c
> @@ -466,8 +466,13 @@ static void do_change_vnc(const char *target, const char *arg)
>  	strcmp(target, "password") == 0) {
>  	char password[9];
>  	if (arg) {
> -	    strncpy(password, arg, sizeof(password));
> -	    password[sizeof(password) - 1] = '\0';
> +            /* "<<unset>>" is 9 chars long, so it is not a valid VNC passwd. */
> +            if (strcmp(arg, "<<unset>>") == 0) {
> +                password[0] = '\0';
> +            } else {
> +                strncpy(password, arg, sizeof(password));
> +                password[sizeof(password) - 1] = '\0';
> +            }
>  	} else
>  	    monitor_readline("Password: ", 1, password, sizeof(password));
>  	if (vnc_display_password(NULL, password) < 0)
>
>
>
>
>
>