Re: [Qemu-devel] [PATCH v4 2/3] qapi: fix crash when a parameter is missing

[Markus Armbruster <armbru@redhat.com>]

Marc-André Lureau <marcandre.lureau@redhat.com> writes:

> Calling:
>
> { "execute": "qom-set",
>   "arguments": { "path": "/machine", "property": "rtc-time" } }
>
> Will crash with:
>
> qapi/qapi-visit-core.c:277: visit_type_any: Assertion `!err != !*obj'
> failed

This is actually a recent regression.  Let's add "Broken in commit
5c678ee."  Can do on commit.

> Clear the obj and return an error.
>
> The patch also fixes a similar potential crash in qmp_input_type_null()
> by checking qmp_input_get_object() returned a valid qobj.
>
> Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com>
> Reviewed-by: Eric Blake <eblake@redhat.com>
> ---
>  qapi/qmp-input-visitor.c | 11 +++++++++++
>  1 file changed, 11 insertions(+)
>
> diff --git a/qapi/qmp-input-visitor.c b/qapi/qmp-input-visitor.c
> index 64dd392..fc91e74 100644
> --- a/qapi/qmp-input-visitor.c
> +++ b/qapi/qmp-input-visitor.c
> @@ -338,6 +338,12 @@ static void qmp_input_type_any(Visitor *v, const char *name, QObject **obj,
>      QmpInputVisitor *qiv = to_qiv(v);
>      QObject *qobj = qmp_input_get_object(qiv, name, true);
>  
> +    if (!qobj) {
> +        error_setg(errp, QERR_MISSING_PARAMETER, name ? name : "null");
> +        *obj = NULL;
> +        return;
> +    }
> +
>      qobject_incref(qobj);
>      *obj = qobj;
>  }
> @@ -347,6 +353,11 @@ static void qmp_input_type_null(Visitor *v, const char *name, Error **errp)
>      QmpInputVisitor *qiv = to_qiv(v);
>      QObject *qobj = qmp_input_get_object(qiv, name, true);
>  
> +    if (!qobj) {
> +        error_setg(errp, QERR_MISSING_PARAMETER, name ? name : "null");
> +        return;
> +    }
> +
>      if (qobject_type(qobj) != QTYPE_QNULL) {
>          error_setg(errp, QERR_INVALID_PARAMETER_TYPE, name ? name : "null",
>                     "null");