[PATCH v2] qga-win: Free GMatchInfo properly

Kostiantyn Kostiuk posted 1 patch 2 days, 7 hours ago
Patches applied successfully (tree, apply log)
git fetch https://github.com/patchew-project/next-importer-push tags/patchew/20210610155811.3313927-1-konstantin@daynix.com
Maintainers: Michael Roth <michael.roth@amd.com>
qga/commands-win32.c | 3 +--
1 file changed, 1 insertion(+), 2 deletions(-)

[PATCH v2] qga-win: Free GMatchInfo properly

Posted by Kostiantyn Kostiuk 2 days, 7 hours ago
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;
             GuestDeviceIdPCI *id;
             if (!g_regex_match(device_pci_re, hw_ids[j], 0, &match_info)) {
                 continue;
@@ -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) {
-- 
2.25.1


Re: [PATCH v2] qga-win: Free GMatchInfo properly

Posted by Philippe Mathieu-Daudé 2 days, 7 hours ago
On 6/10/21 5:58 PM, 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(-)

Reviewed-by: Philippe Mathieu-Daudé <philmd@redhat.com>


Re: [PATCH v2] qga-win: Free GMatchInfo properly

Posted by Daniel P. Berrangé 2 days, 7 hours ago
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

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
-- 
|: https://berrange.com      -o-    https://www.flickr.com/photos/dberrange :|
|: https://libvirt.org         -o-            https://fstop138.berrange.com :|
|: https://entangle-photo.org    -o-    https://www.instagram.com/dberrange :|


Re: [PATCH v2] qga-win: Free GMatchInfo properly

Posted by Konstantin Kostiuk 2 days, 7 hours ago
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
> --
> |: https://berrange.com      -o-
> https://www.flickr.com/photos/dberrange :|
> |: https://libvirt.org         -o-
> https://fstop138.berrange.com :|
> |: https://entangle-photo.org    -o-
> https://www.instagram.com/dberrange :|
>
>

Best wishes,
Kostiantyn Kostiuk

Re: [PATCH v2] qga-win: Free GMatchInfo properly

Posted by Daniel P. Berrangé 2 days, 7 hours ago
On Thu, Jun 10, 2021 at 07:08:36PM +0300, Konstantin Kostiuk wrote:
> 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.

Opps, yes, you are right.

Reviewed-by: Daniel P. Berrangé <berrange@redhat.com>


Regards,
Daniel
-- 
|: https://berrange.com      -o-    https://www.flickr.com/photos/dberrange :|
|: https://libvirt.org         -o-            https://fstop138.berrange.com :|
|: https://entangle-photo.org    -o-    https://www.instagram.com/dberrange :|