[PATCH] qemuDomainDefPostParse: Fail if unable to fill machine type

[Pavel Mores]

On Thu, Apr 16, 2020 at 02:33:33PM +0200, Michal Privoznik wrote:
> Previously, we used virCapabilitiesDomainDataLookup() to fill
> machine type in post parse callback if none was provided in the
> domain XML. If machine type couldn't be filled in an error was
> reported. After 4a4132b4625 we've changed it to
> virQEMUCapsGetPreferredMachine() which returns NULL, but we no
> longer report an error and proceed with the post parse callbacks
> processing. This may lead to a crash because the code later on
> assumes def->os.machine is not NULL.
> 
> Fixes: 4a4132b4625
> 
> Signed-off-by: Michal Privoznik <mprivozn at redhat.com>
> ---
>  src/qemu/qemu_domain.c | 8 ++++++++
>  1 file changed, 8 insertions(+)
> 
> diff --git a/src/qemu/qemu_domain.c b/src/qemu/qemu_domain.c
> index 91e234d644..98ffd23a71 100644
> --- a/src/qemu/qemu_domain.c
> +++ b/src/qemu/qemu_domain.c
> @@ -4973,6 +4973,14 @@ qemuDomainDefPostParse(virDomainDefPtr def,
>      if (!def->os.machine) {
>          const char *machine = virQEMUCapsGetPreferredMachine(qemuCaps,
>                                                               def->virtType);
> +        if (!machine) {
> +            virReportError(VIR_ERR_INVALID_ARG,
> +                           _("could not get preferred machine for %s type=%s"),
> +                           def->emulator,
> +                           virDomainVirtTypeToString(def->virtType));
> +            return -1;
> +        }
> +
>          def->os.machine = g_strdup(machine);
>      }
>  
> -- 
> 2.25.3
> 

Reviewed-by: Pavel Mores <pmores at redhat.com>