drm/radeon: fix race condition UAF in radeon_gem_set_domain_ioctl

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

Posted by Min Li 2 years, 8 months ago

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 <lm0963hack@gmail.com>
---
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

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

Posted by Christian König 2 years, 8 months ago

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 <lm0963hack@gmail.com>

Reviewed-by: Christian König <christian.koenig@amd.com>

> ---
> 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;
>   }
>

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

Posted by Alex Deucher 2 years, 8 months ago

Applied.  Thanks!

On Mon, Jun 5, 2023 at 4:13 AM Christian König <christian.koenig@amd.com> 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 <lm0963hack@gmail.com>
>
> Reviewed-by: Christian König <christian.koenig@amd.com>
>
> > ---
> > 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;
> >   }
> >
>