Re: [PATCH v3] media: rga: fix NULL pointer dereferences, use-after-free, memory leak
From: Steven Price <steven.price@arm.com>
Date: 2019-03-14 10:30:22
Also in:
linux-media, linux-rockchip, lkml
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 <redacted>
Reviewed-by: Steven Price <steven.price@arm.com> Yes, that looks like it solves the issues with the clean up - thanks for reworking it!
quoted hunk ↗ jump to hunk
--- 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