From: Steven Price <steven.price@arm.com> To: Kangjie Lu <kjlu@umn.edu> Cc: Heiko Stuebner <heiko@sntech.de>, Jacob chen <jacob2.chen@rock-chips.com>, linux-kernel@vger.kernel.org, linux-rockchip@lists.infradead.org, pakki001@umn.edu, Mauro Carvalho Chehab <mchehab@kernel.org>, linux-arm-kernel@lists.infradead.org, linux-media@vger.kernel.org Subject: Re: [PATCH v3] media: rga: fix NULL pointer dereferences, use-after-free, memory leak Date: Thu, 14 Mar 2019 10:30:15 +0000 [thread overview] Message-ID: <3471f9df-ad8e-59c8-07d4-454dcc45e480@arm.com> (raw) In-Reply-To: <20190314050344.29790-1-kjlu@umn.edu> 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 <kjlu@umn.edu> Reviewed-by: Steven Price <steven.price@arm.com> 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: >
WARNING: multiple messages have this Message-ID (diff)
From: Steven Price <steven.price@arm.com> To: Kangjie Lu <kjlu@umn.edu> Cc: Heiko Stuebner <heiko@sntech.de>, Jacob chen <jacob2.chen@rock-chips.com>, linux-kernel@vger.kernel.org, linux-rockchip@lists.infradead.org, pakki001@umn.edu, Mauro Carvalho Chehab <mchehab@kernel.org>, linux-arm-kernel@lists.infradead.org, linux-media@vger.kernel.org Subject: Re: [PATCH v3] media: rga: fix NULL pointer dereferences, use-after-free, memory leak Date: Thu, 14 Mar 2019 10:30:15 +0000 [thread overview] Message-ID: <3471f9df-ad8e-59c8-07d4-454dcc45e480@arm.com> (raw) In-Reply-To: <20190314050344.29790-1-kjlu@umn.edu> 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 <kjlu@umn.edu> Reviewed-by: Steven Price <steven.price@arm.com> 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: > _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel
next prev parent reply other threads:[~2019-03-14 10:30 UTC|newest] Thread overview: 16+ messages / expand[flat|nested] mbox.gz Atom feed top 2019-03-09 6:35 [PATCH] media: rga: fix NULL pointer dereferences Kangjie Lu 2019-03-09 6:35 ` Kangjie Lu 2019-03-11 13:15 ` Steven Price 2019-03-11 13:15 ` Steven Price 2019-03-12 6:58 ` [PATCH v2] media: rga: fix NULL pointer dereferences and a memory leak Kangjie Lu 2019-03-12 6:58 ` Kangjie Lu 2019-03-13 13:35 ` Steven Price 2019-03-13 13:35 ` Steven Price 2019-03-14 5:03 ` [PATCH v3] media: rga: fix NULL pointer dereferences, use-after-free, " Kangjie Lu 2019-03-14 5:03 ` Kangjie Lu 2019-03-14 10:30 ` Steven Price [this message] 2019-03-14 10:30 ` Steven Price 2019-03-28 14:47 ` Hans Verkuil 2019-03-28 14:47 ` Hans Verkuil 2019-03-28 15:00 ` Kangjie Lu 2019-03-28 15:00 ` Kangjie Lu
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