Messages in this thread Patch in this message | | | Date | Thu, 24 Aug 2017 20:47:33 +0800 | From | Baoquan He <> | Subject | Re: [PATCH] iommu/amd: Check if domain is NULL before dereference it |
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On 08/24/17 at 03:32pm, Dan Carpenter wrote: > Take a look at this code for example. But all the places which call > get_domain() are the same: > > drivers/iommu/amd_iommu.c > 2648 page = virt_to_page(virt_addr); > 2649 size = PAGE_ALIGN(size); > 2650 > 2651 domain = get_domain(dev); > ^^^^^^^^^^^^^^ > imagined get_domain() returns NULL. > > 2652 if (IS_ERR(domain)) > 2653 goto free_mem; > 2654 > 2655 dma_dom = to_dma_ops_domain(domain); > ^^^^^^^^^^^^^^^^^^^^^^^^^ > This will Oops.
I see, it's a problem. Thanks for telling!
How about below change? But I am not very sure which errno should be picked, seems the latter one, EBUSY is better since it has passed the check_device() checking.
diff --git a/drivers/iommu/amd_iommu.c b/drivers/iommu/amd_iommu.c index 16f1e6af00b0..2d7d04472555 100644 --- a/drivers/iommu/amd_iommu.c +++ b/drivers/iommu/amd_iommu.c @@ -2262,6 +2262,9 @@ static struct protection_domain *get_domain(struct device *dev) domain = to_pdomain(io_domain); attach_device(dev, domain); } + if (domain == NULL) + return ERR_PTR(-EBUSY); + if (!dma_ops_domain(domain)) return ERR_PTR(-EBUSY); -- 2.5.5
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