From mboxrd@z Thu Jan 1 00:00:00 1970 From: davidriley@chromium.org Subject: [PATCH v2 1/4] drm/virtio: Ensure cached capset entries are valid before copying. Date: Mon, 10 Jun 2019 14:18:07 -0700 Message-ID: <20190610211810.253227-2-davidriley__28624.6138204419$1560201516$gmane$org@chromium.org> References: <20190605234423.11348-1-davidriley@chromium.org> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <20190605234423.11348-1-davidriley@chromium.org> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: virtualization-bounces@lists.linux-foundation.org Errors-To: virtualization-bounces@lists.linux-foundation.org To: Gerd Hoffmann , dri-devel@lists.freedesktop.org, virtualization@lists.linux-foundation.org Cc: David Airlie , linux-kernel@vger.kernel.org, Daniel Vetter List-Id: virtualization@lists.linuxfoundation.org From: David Riley virtio_gpu_get_caps_ioctl could return success with invalid data if a second caller to the function occurred after the entry was created in virtio_gpu_cmd_get_capset but prior to the virtio_gpu_cmd_capset_cb callback being called. This could leak contents of memory as well since the caps_cache allocation is done without zeroing. Signed-off-by: David Riley --- drivers/gpu/drm/virtio/virtgpu_ioctl.c | 3 +-- 1 file changed, 1 insertion(+), 2 deletions(-) diff --git a/drivers/gpu/drm/virtio/virtgpu_ioctl.c b/drivers/gpu/drm/virtio/virtgpu_ioctl.c index 949a264985fc..88c1ed57a3c5 100644 --- a/drivers/gpu/drm/virtio/virtgpu_ioctl.c +++ b/drivers/gpu/drm/virtio/virtgpu_ioctl.c @@ -526,7 +526,6 @@ static int virtio_gpu_get_caps_ioctl(struct drm_device *dev, list_for_each_entry(cache_ent, &vgdev->cap_cache, head) { if (cache_ent->id == args->cap_set_id && cache_ent->version == args->cap_set_ver) { - ptr = cache_ent->caps_cache; spin_unlock(&vgdev->display_info_lock); goto copy_exit; } @@ -537,6 +536,7 @@ static int virtio_gpu_get_caps_ioctl(struct drm_device *dev, virtio_gpu_cmd_get_capset(vgdev, found_valid, args->cap_set_ver, &cache_ent); +copy_exit: ret = wait_event_timeout(vgdev->resp_wq, atomic_read(&cache_ent->is_valid), 5 * HZ); if (!ret) @@ -544,7 +544,6 @@ static int virtio_gpu_get_caps_ioctl(struct drm_device *dev, ptr = cache_ent->caps_cache; -copy_exit: if (copy_to_user((void __user *)(unsigned long)args->addr, ptr, size)) return -EFAULT; -- 2.22.0.rc2.383.gf4fbbf30c2-goog