[PATCH AUTOSEL 6.3 25/30] drm/radeon: fix race condition UAF in radeon_gem_set_domain_ioctl

Sasha Levin
2023-06-16T10:28:44Z

From: Min Li <lm0963hack@gmail.com>

[ Upstream commit 982b173a6c6d9472730c3116051977e05d17c8c5 ]

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.

Reviewed-by: Christian König <christian.koenig@amd.com>
Signed-off-by: Min Li <lm0963hack@gmail.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
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 261fcbae88d78..75d79c3110389 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;
}

--
2.39.2