Re: [Qemu-devel] [PATCH 01/21] qga: Fix crash on non-dictionary QMP argument

[Eric Blake]

On 02/23/2017 03:44 PM, Markus Armbruster wrote:
> The value of key 'arguments' must be a JSON object.  qemu-ga neglects
> to check, and crashes.  To reproduce, send
> 
>     { 'execute': 'guest-sync', 'arguments': [] }
> 
> to qemu-ga.
> 
> do_qmp_dispatch() uses qdict_get_qdict() to get the arguments.  When
> not a JSON object, this gets a null pointer, which flows through the
> generated marshalling function to qobject_input_visitor_new(), where
> it fails the assertion.  qmp_dispatch_check_obj() needs to catch this
> error.
> 
> QEMU isn't affected, because it runs qmp_check_input_obj() first,
> which basically duplicates qmp_check_input_obj()'s checks, plus the
> missing one.
> 
> Fix by copying the missing one from qmp_check_input_obj() to
> qmp_dispatch_check_obj().
> 
> Signed-off-by: Markus Armbruster <address@hidden>
> Cc: Michael Roth <address@hidden>
> ---
>  qapi/qmp-dispatch.c | 8 +++++++-
>  1 file changed, 7 insertions(+), 1 deletion(-)

Reviewed-by: Eric Blake <address@hidden>

-- 
Eric Blake   eblake redhat com    +1-919-301-3266
Libvirt virtualization library http://libvirt.org

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