Messages in this thread | | | Subject | Re: [PATCH v3] media: rga: fix NULL pointer dereferences, use-after-free, memory leak | From | Kangjie Lu <> | Date | Thu, 28 Mar 2019 10:00:09 -0500 |
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On 3/28/19 9:47 AM, Hans Verkuil wrote: > Hi Kangjie, > > Unfortunately there are more issues with the cleanup sequence in > this probe function: > > On 3/14/19 6:03 AM, 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> >> --- >> 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; > Actually, the unreg_video_dev label makes no sense: if the video device > is successfully registered, then probe() returns 0. So you never need to > unregister the video device again. You *do* need to release it with > video_device_release(). > > So this should be a goto rel_vdev. > > And the cleanup sequence at the end also fails to call v4l2_m2m_release(). > > Can you make v4?
Thanks for the feedback. Will send a v4.
> > Thanks! > > Hans > >> + } >> >> 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); >> +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: >>
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