linux-kernel - [PATCH v18 22/26] drm/shmem-helper: Don't free refcounted GEM

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <20231029230205.93277-23-dmitry.osipenko@collabora.com>
Date:   Mon, 30 Oct 2023 02:02:01 +0300
From:   Dmitry Osipenko <dmitry.osipenko@...labora.com>
To:     David Airlie <airlied@...il.com>,
        Gerd Hoffmann <kraxel@...hat.com>,
        Gurchetan Singh <gurchetansingh@...omium.org>,
        Chia-I Wu <olvaffe@...il.com>, Daniel Vetter <daniel@...ll.ch>,
        Maarten Lankhorst <maarten.lankhorst@...ux.intel.com>,
        Maxime Ripard <mripard@...nel.org>,
        Thomas Zimmermann <tzimmermann@...e.de>,
        Christian König <christian.koenig@....com>,
        Qiang Yu <yuq825@...il.com>,
        Steven Price <steven.price@....com>,
        Boris Brezillon <boris.brezillon@...labora.com>,
        Emma Anholt <emma@...olt.net>, Melissa Wen <mwen@...lia.com>
Cc:     dri-devel@...ts.freedesktop.org, linux-kernel@...r.kernel.org,
        kernel@...labora.com, virtualization@...ts.linux-foundation.org
Subject: [PATCH v18 22/26] drm/shmem-helper: Don't free refcounted GEM

Don't free refcounted shmem object to prevent use-after-free bug that
is worse than a memory leak.

Signed-off-by: Dmitry Osipenko <dmitry.osipenko@...labora.com>
---
 drivers/gpu/drm/drm_gem_shmem_helper.c | 7 ++++---
 1 file changed, 4 insertions(+), 3 deletions(-)

diff --git a/drivers/gpu/drm/drm_gem_shmem_helper.c b/drivers/gpu/drm/drm_gem_shmem_helper.c
index 6dd087f19ea3..4253c367dc07 100644
--- a/drivers/gpu/drm/drm_gem_shmem_helper.c
+++ b/drivers/gpu/drm/drm_gem_shmem_helper.c
@@ -203,9 +203,10 @@ void drm_gem_shmem_free(struct drm_gem_shmem_object *shmem)
 	if (obj->import_attach)
 		drm_prime_gem_destroy(obj, shmem->sgt);
 
-	drm_WARN_ON(obj->dev, refcount_read(&shmem->vmap_use_count));
-	drm_WARN_ON(obj->dev, refcount_read(&shmem->pages_use_count));
-	drm_WARN_ON(obj->dev, refcount_read(&shmem->pages_pin_count));
+	if (drm_WARN_ON(obj->dev, refcount_read(&shmem->vmap_use_count)) ||
+	    drm_WARN_ON(obj->dev, refcount_read(&shmem->pages_use_count)) ||
+	    drm_WARN_ON(obj->dev, refcount_read(&shmem->pages_pin_count)))
+		return;
 
 	drm_gem_object_release(obj);
 	kfree(shmem);
-- 
2.41.0