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authorDavid Rientjes <rientjes@google.com>2020-06-11 12:20:30 -0700
committerChristoph Hellwig <hch@lst.de>2020-06-17 09:29:38 +0200
commit56fccf21d1961a06e2a0c96ce446ebf036651062 (patch)
treec47f6ddb7b3afd5e0ffefafad4af257cb200b486 /kernel
parent96a539fa3bb71f443ae08e57b9f63d6e5bb2207c (diff)
downloadlinux-56fccf21d1961a06e2a0c96ce446ebf036651062.tar.bz2
dma-direct: check return value when encrypting or decrypting memory
__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: c10f07aa27da ("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>
Diffstat (limited to 'kernel')
-rw-r--r--kernel/dma/direct.c19
1 files changed, 14 insertions, 5 deletions
diff --git a/kernel/dma/direct.c b/kernel/dma/direct.c
index 80d33f215a2e..2f69bfdbe315 100644
--- a/kernel/dma/direct.c
+++ b/kernel/dma/direct.c
@@ -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),
- 1 << get_order(size));
+ 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;