On Thu, Jun 10, 2021 at 7:02 PM Daniel P. Berrangé <berrange@redhat.com>
wrote:

> On Thu, Jun 10, 2021 at 06:58:11PM +0300, Kostiantyn Kostiuk wrote:
> > The g_regex_match function creates match_info even if it
> > returns FALSE. So we should always call g_match_info_free.
> > A better solution is using g_autoptr for match_info variable.
> >
> > Signed-off-by: Kostiantyn Kostiuk <konstantin@daynix.com>
> > ---
> >  qga/commands-win32.c | 3 +--
> >  1 file changed, 1 insertion(+), 2 deletions(-)
> >
> > diff --git a/qga/commands-win32.c b/qga/commands-win32.c
> > index 300b87c859..785a5cc6b2 100644
> > --- a/qga/commands-win32.c
> > +++ b/qga/commands-win32.c
> > @@ -2494,7 +2494,7 @@ GuestDeviceInfoList *qmp_guest_get_devices(Error
> **errp)
> >              continue;
> >          }
> >          for (j = 0; hw_ids[j] != NULL; j++) {
> > -            GMatchInfo *match_info;
> > +            g_autoptr(GMatchInfo) match_info;
>
> This should be initialized to NULL otherwise...
>
> >              GuestDeviceIdPCI *id;
> >              if (!g_regex_match(device_pci_re, hw_ids[j], 0,
> &match_info)) {
> >                  continue;
>
> this continue will trigger freeing of unintialized memory
>

But we always call match_info, so match_info is always initialized.
The g_regex_match function creates match_info even if it returns FALSE.


>
> Essentially all g_auto* variables should be init to NULL
> at all times, even if it currently looks harmless.
>
> > @@ -2511,7 +2511,6 @@ GuestDeviceInfoList *qmp_guest_get_devices(Error
> **errp)
> >              id->vendor_id = g_ascii_strtoull(vendor_id, NULL, 16);
> >              id->device_id = g_ascii_strtoull(device_id, NULL, 16);
> >
> > -            g_match_info_free(match_info);
> >              break;
> >          }
> >          if (skip) {
>
> Regards,
> Daniel
> --
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>
>

Best wishes,
Kostiantyn Kostiuk