From patchwork Fri Nov 27 09:43:55 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Qinglang Miao X-Patchwork-Id: 11935393 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-16.7 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_GIT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 0498FC2D0E4 for ; Fri, 27 Nov 2020 10:11:53 +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 91434206CA for ; Fri, 27 Nov 2020 10:11:52 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 91434206CA Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=huawei.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 99D0C6EB9B; Fri, 27 Nov 2020 10:11:40 +0000 (UTC) Received: from szxga05-in.huawei.com (szxga05-in.huawei.com [45.249.212.191]) by gabe.freedesktop.org (Postfix) with ESMTPS id CD5936EB65 for ; Fri, 27 Nov 2020 09:39:53 +0000 (UTC) Received: from DGGEMS401-HUB.china.huawei.com (unknown [172.30.72.59]) by szxga05-in.huawei.com (SkyGuard) with ESMTP id 4Cj8jC4pSwzhjJL; Fri, 27 Nov 2020 17:39:27 +0800 (CST) Received: from localhost.localdomain.localdomain (10.175.113.25) by DGGEMS401-HUB.china.huawei.com (10.3.19.201) with Microsoft SMTP Server id 14.3.487.0; Fri, 27 Nov 2020 17:39:39 +0800 From: Qinglang Miao To: Maarten Lankhorst , Maxime Ripard , Thomas Zimmermann , David Airlie , Daniel Vetter Subject: [PATCH] drm/dev: Fix NULL pointer dereference in drm_minor_alloc Date: Fri, 27 Nov 2020 17:43:55 +0800 Message-ID: <20201127094355.120520-1-miaoqinglang@huawei.com> X-Mailer: git-send-email 2.20.1 MIME-Version: 1.0 X-Originating-IP: [10.175.113.25] X-CFilter-Loop: Reflected X-Mailman-Approved-At: Fri, 27 Nov 2020 10:11:27 +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: Qinglang Miao , linux-kernel@vger.kernel.org, dri-devel@lists.freedesktop.org Errors-To: dri-devel-bounces@lists.freedesktop.org Sender: "dri-devel" KASAN: null-ptr-deref in range [0x0000000000000030-0x0000000000000037] CPU: 0 PID: 18491 Comm: syz-executor.0 Tainted: G C 5.10.0-rc4+ #1 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.13.0-1ubuntu1 04/01/2014 RIP: 0010:kobject_put+0x2f/0x140 Call Trace: put_device+0x20/0x40 drm_minor_alloc_release+0x60/0xe0 [drm] drm_managed_release+0x1b6/0x440 [drm] drm_dev_init+0x50b/0x8e0 [drm] __devm_drm_dev_alloc+0x50/0x160 [drm] vgem_init+0x15c/0x1000 [vgem] do_one_initcall+0x149/0x7e0 do_init_module+0x1ef/0x700 load_module+0x3467/0x4140 __do_sys_finit_module+0x10d/0x1a0 do_syscall_64+0x34/0x80 entry_SYSCALL_64_after_hwframe+0x44/0xa9 kfree(minor->kdev) in put_device would raise a null-ptr-deref bug when minor->kdev is null or error pointer. So do check before put_device in drm_minor_alloc_release and prohibit minor->kdev becoming an error pointer. Fixes: f96306f9892b ("drm: manage drm_minor cleanup with drmm_") Signed-off-by: Qinglang Miao --- drivers/gpu/drm/drm_drv.c | 10 +++++++--- 1 file changed, 7 insertions(+), 3 deletions(-) diff --git a/drivers/gpu/drm/drm_drv.c b/drivers/gpu/drm/drm_drv.c index cd162d406..c253d3cd4 100644 --- a/drivers/gpu/drm/drm_drv.c +++ b/drivers/gpu/drm/drm_drv.c @@ -100,7 +100,8 @@ static void drm_minor_alloc_release(struct drm_device *dev, void *data) WARN_ON(dev != minor->dev); - put_device(minor->kdev); + if (minor->kdev) + put_device(minor->kdev); spin_lock_irqsave(&drm_minor_lock, flags); idr_remove(&drm_minors_idr, minor->index); @@ -140,8 +141,11 @@ static int drm_minor_alloc(struct drm_device *dev, unsigned int type) return r; minor->kdev = drm_sysfs_minor_alloc(minor); - if (IS_ERR(minor->kdev)) - return PTR_ERR(minor->kdev); + if (IS_ERR(minor->kdev)) { + r = PTR_ERR(minor->kdev); + minor->kdev = NULL; + return r; + } *drm_minor_get_slot(dev, type) = minor; return 0;