From patchwork Mon Apr 27 21:44:05 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Ezequiel Garcia X-Patchwork-Id: 11514431 Return-Path: Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 64B8114B4 for ; Tue, 28 Apr 2020 12:47:09 +0000 (UTC) Received: from gabe.freedesktop.org (gabe.freedesktop.org [131.252.210.177]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 4E200206D6 for ; Tue, 28 Apr 2020 12:47:09 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 4E200206D6 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=collabora.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=dri-devel-bounces@lists.freedesktop.org Received: from gabe.freedesktop.org (localhost [127.0.0.1]) by gabe.freedesktop.org (Postfix) with ESMTP id 3C8BD6E39B; Tue, 28 Apr 2020 12:46:25 +0000 (UTC) X-Original-To: dri-devel@lists.freedesktop.org Delivered-To: dri-devel@lists.freedesktop.org Received: from bhuna.collabora.co.uk (bhuna.collabora.co.uk [IPv6:2a00:1098:0:82:1000:25:2eeb:e3e3]) by gabe.freedesktop.org (Postfix) with ESMTPS id DB9F46E116 for ; Mon, 27 Apr 2020 21:44:23 +0000 (UTC) Received: from [127.0.0.1] (localhost [127.0.0.1]) (Authenticated sender: ezequiel) with ESMTPSA id 152542A0A40 From: Ezequiel Garcia To: dri-devel@lists.freedesktop.org Subject: [PATCH] drm/vkms: Hold gem object while still in-use Date: Mon, 27 Apr 2020 18:44:05 -0300 Message-Id: <20200427214405.13069-1-ezequiel@collabora.com> X-Mailer: git-send-email 2.26.0.rc2 MIME-Version: 1.0 X-Mailman-Approved-At: Tue, 28 Apr 2020 12:46:22 +0000 X-BeenThere: dri-devel@lists.freedesktop.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Direct Rendering Infrastructure - Development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Haneen Mohammed , syzbot+e3372a2afe1e7ef04bc7@syzkaller.appspotmail.com, Rodrigo Siqueira , David Airlie , Ezequiel Garcia Errors-To: dri-devel-bounces@lists.freedesktop.org Sender: "dri-devel" We need to keep the reference to the drm_gem_object until the last access by vkms_dumb_create. Therefore, the put the object after it is used. This fixes a use-after-free issue reported by syzbot. While here, change vkms_gem_create() symbol to static. Reported-and-tested-by: syzbot+e3372a2afe1e7ef04bc7@syzkaller.appspotmail.com Signed-off-by: Ezequiel Garcia Reviewed-by: Rodrigo Siqueira --- drivers/gpu/drm/vkms/vkms_drv.h | 5 ----- drivers/gpu/drm/vkms/vkms_gem.c | 11 ++++++----- 2 files changed, 6 insertions(+), 10 deletions(-) diff --git a/drivers/gpu/drm/vkms/vkms_drv.h b/drivers/gpu/drm/vkms/vkms_drv.h index eda04ffba7b1..f4036bb0b9a8 100644 --- a/drivers/gpu/drm/vkms/vkms_drv.h +++ b/drivers/gpu/drm/vkms/vkms_drv.h @@ -117,11 +117,6 @@ struct drm_plane *vkms_plane_init(struct vkms_device *vkmsdev, enum drm_plane_type type, int index); /* Gem stuff */ -struct drm_gem_object *vkms_gem_create(struct drm_device *dev, - struct drm_file *file, - u32 *handle, - u64 size); - vm_fault_t vkms_gem_fault(struct vm_fault *vmf); int vkms_dumb_create(struct drm_file *file, struct drm_device *dev, diff --git a/drivers/gpu/drm/vkms/vkms_gem.c b/drivers/gpu/drm/vkms/vkms_gem.c index 2e01186fb943..c541fec57566 100644 --- a/drivers/gpu/drm/vkms/vkms_gem.c +++ b/drivers/gpu/drm/vkms/vkms_gem.c @@ -97,10 +97,10 @@ vm_fault_t vkms_gem_fault(struct vm_fault *vmf) return ret; } -struct drm_gem_object *vkms_gem_create(struct drm_device *dev, - struct drm_file *file, - u32 *handle, - u64 size) +static struct drm_gem_object *vkms_gem_create(struct drm_device *dev, + struct drm_file *file, + u32 *handle, + u64 size) { struct vkms_gem_object *obj; int ret; @@ -113,7 +113,6 @@ struct drm_gem_object *vkms_gem_create(struct drm_device *dev, return ERR_CAST(obj); ret = drm_gem_handle_create(file, &obj->gem, handle); - drm_gem_object_put_unlocked(&obj->gem); if (ret) return ERR_PTR(ret); @@ -142,6 +141,8 @@ int vkms_dumb_create(struct drm_file *file, struct drm_device *dev, args->size = gem_obj->size; args->pitch = pitch; + drm_gem_object_put_unlocked(gem_obj); + DRM_DEBUG_DRIVER("Created object of size %lld\n", size); return 0;