From mboxrd@z Thu Jan 1 00:00:00 1970 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=-7.0 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_PASS,URIBL_BLOCKED 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 2DA86C43381 for ; Thu, 14 Mar 2019 10:30:22 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id E355021019 for ; Thu, 14 Mar 2019 10:30:21 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727382AbfCNKaU (ORCPT ); Thu, 14 Mar 2019 06:30:20 -0400 Received: from foss.arm.com ([217.140.101.70]:41852 "EHLO foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726629AbfCNKaT (ORCPT ); Thu, 14 Mar 2019 06:30:19 -0400 Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.72.51.249]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id 2B06D80D; Thu, 14 Mar 2019 03:30:19 -0700 (PDT) Received: from [10.1.196.69] (e112269-lin.cambridge.arm.com [10.1.196.69]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id A337D3F71D; Thu, 14 Mar 2019 03:30:17 -0700 (PDT) Subject: Re: [PATCH v3] media: rga: fix NULL pointer dereferences, use-after-free, memory leak To: Kangjie Lu Cc: Heiko Stuebner , Jacob chen , linux-kernel@vger.kernel.org, linux-rockchip@lists.infradead.org, pakki001@umn.edu, Mauro Carvalho Chehab , linux-arm-kernel@lists.infradead.org, linux-media@vger.kernel.org References: <20190314050344.29790-1-kjlu@umn.edu> From: Steven Price Message-ID: <3471f9df-ad8e-59c8-07d4-454dcc45e480@arm.com> Date: Thu, 14 Mar 2019 10:30:15 +0000 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:60.0) Gecko/20100101 Thunderbird/60.5.1 MIME-Version: 1.0 In-Reply-To: <20190314050344.29790-1-kjlu@umn.edu> Content-Type: text/plain; charset=utf-8 Content-Language: en-GB Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 14/03/2019 05:03, Kangjie Lu wrote: > 1. dma_alloc_attrs, __get_free_pages can fail and return NULL. > Further uses of their return values lead to NULL pointer > dereferences > > 2. In the error-handling path, video_unregister_device uses > "rga->vfd" which has been freed by video_device_release > > 3. The error handling for v4l2_m2m_init and video_register_device > has memory-leak issues > > The patch fixes the above issues. > > Signed-off-by: Kangjie Lu Reviewed-by: Steven Price Yes, that looks like it solves the issues with the clean up - thanks for reworking it! > --- > drivers/media/platform/rockchip/rga/rga.c | 26 ++++++++++++++++++++--- > 1 file changed, 23 insertions(+), 3 deletions(-) > > diff --git a/drivers/media/platform/rockchip/rga/rga.c b/drivers/media/platform/rockchip/rga/rga.c > index 5c653287185f..468365ceb99d 100644 > --- a/drivers/media/platform/rockchip/rga/rga.c > +++ b/drivers/media/platform/rockchip/rga/rga.c > @@ -889,11 +889,24 @@ static int rga_probe(struct platform_device *pdev) > rga->cmdbuf_virt = dma_alloc_attrs(rga->dev, RGA_CMDBUF_SIZE, > &rga->cmdbuf_phy, GFP_KERNEL, > DMA_ATTR_WRITE_COMBINE); > + if (!rga->cmdbuf_virt) { > + ret = -ENOMEM; > + goto unreg_video_dev; > + } > > rga->src_mmu_pages = > (unsigned int *)__get_free_pages(GFP_KERNEL | __GFP_ZERO, 3); > + if (!rga->src_mmu_pages) { > + ret = -ENOMEM; > + goto free_dma_attrs; > + } > + > rga->dst_mmu_pages = > (unsigned int *)__get_free_pages(GFP_KERNEL | __GFP_ZERO, 3); > + if (!rga->dst_mmu_pages) { > + ret = -ENOMEM; > + goto free_dst_pages; > + } > > def_frame.stride = (def_frame.width * def_frame.fmt->depth) >> 3; > def_frame.size = def_frame.stride * def_frame.height; > @@ -901,7 +914,7 @@ static int rga_probe(struct platform_device *pdev) > ret = video_register_device(vfd, VFL_TYPE_GRABBER, -1); > if (ret) { > v4l2_err(&rga->v4l2_dev, "Failed to register video device\n"); > - goto rel_vdev; > + goto free_pages; > } > > v4l2_info(&rga->v4l2_dev, "Registered %s as /dev/%s\n", > @@ -909,10 +922,17 @@ static int rga_probe(struct platform_device *pdev) > > return 0; > > -rel_vdev: > - video_device_release(vfd); > +free_pages: > + free_pages((unsigned long)rga->src_mmu_pages, 3); > +free_dst_pages: > + free_pages((unsigned long)rga->dst_mmu_pages, 3); Minor comment: free_pages accepts a NULL pointer (or more precisely 0, since it takes an unsigned long), it just returns having done nothing. So there isn't actually any harm in calling free_pages unconditionally in the error path (since rga is initialised to all zeros). You can save a couple of labels in the error path using that trick. Thanks, Steve > +free_dma_attrs: > + dma_free_attrs(rga->dev, RGA_CMDBUF_SIZE, rga->cmdbuf_virt, > + rga->cmdbuf_phy, > + DMA_ATTR_WRITE_COMBINE); > unreg_video_dev: > video_unregister_device(rga->vfd); > + video_device_release(vfd); > unreg_v4l2_dev: > v4l2_device_unregister(&rga->v4l2_dev); > err_put_clk: >