dma-direct: check return value when encrypting or decrypting memory (56fccf21) · Commits · 戴 / test

__change_page_attr() can fail which will cause set_memory_encrypted() and set_memory_decrypted() to return non-zero. If the device requires unencrypted DMA memory and decryption fails, simply free the memory and fail. If attempting to re-encrypt in the failure path and that encryption fails, there is no alternative other than to leak the memory. Fixes: ("dma/direct: Handle force decryption for DMA coherent buffers in common code") Signed-off-by:

David Rientjes <rientjes@google.com> Signed-off-by:

Christoph Hellwig <hch@lst.de>

kernel/dma/direct.c

+14 −5

Original line number	Diff line number	Diff line
		@@ -158,6 +158,7 @@ void dma_direct_alloc_pages(struct device dev, size_t size,
		{
		struct page *page;
		void *ret;
		int err;

		size = PAGE_ALIGN(size);

		@@ -210,8 +211,12 @@ void dma_direct_alloc_pages(struct device dev, size_t size,
		}

		ret = page_address(page);
		if (force_dma_unencrypted(dev))
		set_memory_decrypted((unsigned long)ret, 1 << get_order(size));
		if (force_dma_unencrypted(dev)) {
		err = set_memory_decrypted((unsigned long)ret,
		1 << get_order(size));
		if (err)
		goto out_free_pages;
		}

		memset(ret, 0, size);

		@@ -230,9 +235,13 @@ done:
		return ret;

		out_encrypt_pages:
		if (force_dma_unencrypted(dev))
		set_memory_encrypted((unsigned long)page_address(page),
		if (force_dma_unencrypted(dev)) {
		err = set_memory_encrypted((unsigned long)page_address(page),
		1 << get_order(size));
		/* If memory cannot be re-encrypted, it must be leaked */
		if (err)
		return NULL;
		}
		out_free_pages:
		dma_free_contiguous(dev, page, size);
		return NULL;

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