From: Robin Murphy <robin.murphy@arm.com>
To: Christoph Hellwig <hch@lst.de>, iommu@lists.linux-foundation.org
Cc: David Rientjes <rientjes@google.com>
Subject: Re: [PATCH 03/10] dma-direct: leak memory that can't be re-encrypted
Date: Thu, 4 Nov 2021 12:35:49 +0000 [thread overview]
Message-ID: <8556aafc-f006-ad25-3bd0-0664d06dcaaf@arm.com> (raw)
In-Reply-To: <20211021090611.488281-4-hch@lst.de>
On 2021-10-21 10:06, Christoph Hellwig wrote:
> We must never unencryped memory go back into the general page pool.
> So if we fail to set it back to encrypted when freeing DMA memory, leak
> the memory insted and warn the user.
>
> Signed-off-by: Christoph Hellwig <hch@lst.de>
> ---
> kernel/dma/direct.c | 18 ++++++++++++++----
> 1 file changed, 14 insertions(+), 4 deletions(-)
>
> diff --git a/kernel/dma/direct.c b/kernel/dma/direct.c
> index 2fef8dd401fe9..60cb75aa6778e 100644
> --- a/kernel/dma/direct.c
> +++ b/kernel/dma/direct.c
> @@ -263,9 +263,11 @@ void *dma_direct_alloc(struct device *dev, size_t size,
> return ret;
>
> out_encrypt_pages:
> - /* If memory cannot be re-encrypted, it must be leaked */
> - if (dma_set_encrypted(dev, page_address(page), size))
> + if (dma_set_encrypted(dev, page_address(page), size)) {
> + pr_warn_ratelimited(
> + "leaking DMA memory that can't be re-encrypted\n");
Given that this is consistent for all uses of dma_set_encrypted(), seems
like it should be factored into the helper itself.
Robin.
> return NULL;
> + }
> out_unmap_pages:
> if (IS_ENABLED(CONFIG_DMA_REMAP) && is_vmalloc_addr(ret))
> vunmap(ret);
> @@ -307,7 +309,11 @@ void dma_direct_free(struct device *dev, size_t size,
> dma_free_from_pool(dev, cpu_addr, PAGE_ALIGN(size)))
> return;
>
> - dma_set_encrypted(dev, cpu_addr, 1 << page_order);
> + if (dma_set_encrypted(dev, cpu_addr, 1 << page_order)) {
> + pr_warn_ratelimited(
> + "leaking DMA memory that can't be re-encrypted\n");
> + return;
> + }
>
> if (IS_ENABLED(CONFIG_DMA_REMAP) && is_vmalloc_addr(cpu_addr))
> vunmap(cpu_addr);
> @@ -365,7 +371,11 @@ void dma_direct_free_pages(struct device *dev, size_t size,
> dma_free_from_pool(dev, vaddr, size))
> return;
>
> - dma_set_encrypted(dev, vaddr, 1 << page_order);
> + if (dma_set_encrypted(dev, vaddr, 1 << page_order)) {
> + pr_warn_ratelimited(
> + "leaking DMA memory that can't be re-encrypted\n");
> + return;
> + }
> __dma_direct_free_pages(dev, page, size);
> }
>
>
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next prev parent reply other threads:[~2021-11-04 12:35 UTC|newest]
Thread overview: 29+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-10-21 9:06 dma-direct fixes and cleanups v2 Christoph Hellwig
2021-10-21 9:06 ` [PATCH 01/10] dma-direct: factor out dma_set_{de,en}crypted helpers Christoph Hellwig
2021-11-04 12:35 ` Robin Murphy
2021-10-21 9:06 ` [PATCH 02/10] dma-direct: unmapped remapped pages when dma_set_decrypted Christoph Hellwig
2021-11-04 12:35 ` Robin Murphy
2021-11-09 14:10 ` Christoph Hellwig
2021-11-09 14:27 ` Robin Murphy
2021-10-21 9:06 ` [PATCH 03/10] dma-direct: leak memory that can't be re-encrypted Christoph Hellwig
2021-11-04 12:35 ` Robin Murphy [this message]
2021-11-09 14:19 ` Christoph Hellwig
2021-10-21 9:06 ` [PATCH 04/10] dma-direct: clean up the remapping checks in dma_direct_alloc Christoph Hellwig
2021-11-04 12:35 ` Robin Murphy
2021-11-09 14:23 ` Christoph Hellwig
2021-10-21 9:06 ` [PATCH 05/10] dma-direct: factor out a helper for DMA_ATTR_NO_KERNEL_MAPPING allocations Christoph Hellwig
2021-11-04 12:36 ` Robin Murphy
2021-11-09 14:25 ` Christoph Hellwig
2021-11-09 14:39 ` Robin Murphy
2021-10-21 9:06 ` [PATCH 06/10] dma-direct: refactor the !coherent checks in dma_direct_alloc Christoph Hellwig
2021-11-04 12:36 ` Robin Murphy
2021-11-09 14:27 ` Christoph Hellwig
2021-10-21 9:06 ` [PATCH 07/10] dma-direct: warn if there is no pool for force unencrypted allocations Christoph Hellwig
2021-11-04 12:36 ` Robin Murphy
2021-10-21 9:06 ` [PATCH 08/10] dma-direct: drop two CONFIG_DMA_RESTRICTED_POOL conditionals Christoph Hellwig
2021-11-04 12:37 ` Robin Murphy
2021-10-21 9:06 ` [PATCH 09/10] dma-direct: factor the swiotlb code out of __dma_direct_alloc_pages Christoph Hellwig
2021-11-04 12:37 ` Robin Murphy
2021-10-21 9:06 ` [PATCH 10/10] dma-direct: add a dma_direct_use_pool helper Christoph Hellwig
2021-11-04 12:37 ` Robin Murphy
2021-11-04 8:54 ` dma-direct fixes and cleanups v2 Christoph Hellwig
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