2023-06-03 08:19:30

by Min Li

Subject: [PATCH v2] drm/radeon: fix race condition UAF in radeon_gem_set_domain_ioctl

Userspace can race to free the gobj(robj converted from), robj should not
be accessed again after drm_gem_object_put, otherwith it will result in
use-after-free.

Signed-off-by: Min Li <[email protected]>
---
Changes in v2:
- Remove unused robj, avoid compile complain

drivers/gpu/drm/radeon/radeon_gem.c | 4 +---
1 file changed, 1 insertion(+), 3 deletions(-)

diff --git a/drivers/gpu/drm/radeon/radeon_gem.c b/drivers/gpu/drm/radeon/radeon_gem.c
index bdc5af23f005..d3f5ddbc1704 100644
--- a/drivers/gpu/drm/radeon/radeon_gem.c
+++ b/drivers/gpu/drm/radeon/radeon_gem.c
@@ -459,7 +459,6 @@ int radeon_gem_set_domain_ioctl(struct drm_device *dev, void *data,
struct radeon_device *rdev = dev->dev_private;
struct drm_radeon_gem_set_domain *args = data;
struct drm_gem_object *gobj;
- struct radeon_bo *robj;
int r;

/* for now if someone requests domain CPU -
@@ -472,13 +471,12 @@ int radeon_gem_set_domain_ioctl(struct drm_device *dev, void *data,
up_read(&rdev->exclusive_lock);
return -ENOENT;
}
- robj = gem_to_radeon_bo(gobj);

r = radeon_gem_set_domain(gobj, args->read_domains, args->write_domain);

drm_gem_object_put(gobj);
up_read(&rdev->exclusive_lock);
- r = radeon_gem_handle_lockup(robj->rdev, r);
+ r = radeon_gem_handle_lockup(rdev, r);
return r;
}

--
2.34.1

2023-06-05 08:32:48

by Christian König

Subject: Re: [PATCH v2] drm/radeon: fix race condition UAF in radeon_gem_set_domain_ioctl

Am 03.06.23 um 09:43 schrieb Min Li:
> Userspace can race to free the gobj(robj converted from), robj should not
> be accessed again after drm_gem_object_put, otherwith it will result in
> use-after-free.
>
> Signed-off-by: Min Li <[email protected]>

Reviewed-by: Christian König <[email protected]>

> ---
> Changes in v2:
> - Remove unused robj, avoid compile complain
>
> drivers/gpu/drm/radeon/radeon_gem.c | 4 +---
> 1 file changed, 1 insertion(+), 3 deletions(-)
>
> diff --git a/drivers/gpu/drm/radeon/radeon_gem.c b/drivers/gpu/drm/radeon/radeon_gem.c
> index bdc5af23f005..d3f5ddbc1704 100644
> --- a/drivers/gpu/drm/radeon/radeon_gem.c
> +++ b/drivers/gpu/drm/radeon/radeon_gem.c
> @@ -459,7 +459,6 @@ int radeon_gem_set_domain_ioctl(struct drm_device *dev, void *data,
> struct radeon_device *rdev = dev->dev_private;
> struct drm_radeon_gem_set_domain *args = data;
> struct drm_gem_object *gobj;
> - struct radeon_bo *robj;
> int r;
>
> /* for now if someone requests domain CPU -
> @@ -472,13 +471,12 @@ int radeon_gem_set_domain_ioctl(struct drm_device *dev, void *data,
> up_read(&rdev->exclusive_lock);
> return -ENOENT;
> }
> - robj = gem_to_radeon_bo(gobj);
>
> r = radeon_gem_set_domain(gobj, args->read_domains, args->write_domain);
>
> drm_gem_object_put(gobj);
> up_read(&rdev->exclusive_lock);
> - r = radeon_gem_handle_lockup(robj->rdev, r);
> + r = radeon_gem_handle_lockup(rdev, r);
> return r;
> }
>

2023-06-05 15:31:52

by Alex Deucher

Subject: Re: [PATCH v2] drm/radeon: fix race condition UAF in radeon_gem_set_domain_ioctl

Applied. Thanks!

On Mon, Jun 5, 2023 at 4:13 AM Christian König <[email protected]> wrote:
>
> Am 03.06.23 um 09:43 schrieb Min Li:
> > Userspace can race to free the gobj(robj converted from), robj should not
> > be accessed again after drm_gem_object_put, otherwith it will result in
> > use-after-free.
> >
> > Signed-off-by: Min Li <[email protected]>
>
> Reviewed-by: Christian König <[email protected]>
>
> > ---
> > Changes in v2:
> > - Remove unused robj, avoid compile complain
> >
> > drivers/gpu/drm/radeon/radeon_gem.c | 4 +---
> > 1 file changed, 1 insertion(+), 3 deletions(-)
> >
> > diff --git a/drivers/gpu/drm/radeon/radeon_gem.c b/drivers/gpu/drm/radeon/radeon_gem.c
> > index bdc5af23f005..d3f5ddbc1704 100644
> > --- a/drivers/gpu/drm/radeon/radeon_gem.c
> > +++ b/drivers/gpu/drm/radeon/radeon_gem.c
> > @@ -459,7 +459,6 @@ int radeon_gem_set_domain_ioctl(struct drm_device *dev, void *data,
> > struct radeon_device *rdev = dev->dev_private;
> > struct drm_radeon_gem_set_domain *args = data;
> > struct drm_gem_object *gobj;
> > - struct radeon_bo *robj;
> > int r;
> >
> > /* for now if someone requests domain CPU -
> > @@ -472,13 +471,12 @@ int radeon_gem_set_domain_ioctl(struct drm_device *dev, void *data,
> > up_read(&rdev->exclusive_lock);
> > return -ENOENT;
> > }
> > - robj = gem_to_radeon_bo(gobj);
> >
> > r = radeon_gem_set_domain(gobj, args->read_domains, args->write_domain);
> >
> > drm_gem_object_put(gobj);
> > up_read(&rdev->exclusive_lock);
> > - r = radeon_gem_handle_lockup(robj->rdev, r);
> > + r = radeon_gem_handle_lockup(rdev, r);
> > return r;
> > }
> >
>