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| author | Robin Murphy <robin.murphy@arm.com> | 2022-05-20 18:10:13 +0100 |
|---|---|---|
| committer | Christoph Hellwig <hch@lst.de> | 2022-05-23 15:25:40 +0200 |
| commit | 4a37f3dd9a83186cb88d44808ab35b78375082c9 (patch) | |
| tree | ba5dc0010beb736ab375eecc72890bb71a4cb131 /kernel/dma | |
| parent | 82806744fd7dde603b64c151eeddaa4ee62193fd (diff) | |
| download | linux-4a37f3dd9a83186cb88d44808ab35b78375082c9.tar.bz2 | |
dma-direct: don't over-decrypt memory
The original x86 sev_alloc() only called set_memory_decrypted() on
memory returned by alloc_pages_node(), so the page order calculation
fell out of that logic. However, the common dma-direct code has several
potential allocators, not all of which are guaranteed to round up the
underlying allocation to a power-of-two size, so carrying over that
calculation for the encryption/decryption size was a mistake. Fix it by
rounding to a *number* of pages, rather than an order.
Until recently there was an even worse interaction with DMA_DIRECT_REMAP
where we could have ended up decrypting part of the next adjacent
vmalloc area, only averted by no architecture actually supporting both
configs at once. Don't ask how I found that one out...
Fixes: c10f07aa27da ("dma/direct: Handle force decryption for DMA coherent buffers in common code")
Signed-off-by: Robin Murphy <robin.murphy@arm.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Acked-by: David Rientjes <rientjes@google.com>
Diffstat (limited to 'kernel/dma')
| -rw-r--r-- | kernel/dma/direct.c | 4 |
1 files changed, 2 insertions, 2 deletions
diff --git a/kernel/dma/direct.c b/kernel/dma/direct.c index 3e7f4aab740e..e978f36e6be8 100644 --- a/kernel/dma/direct.c +++ b/kernel/dma/direct.c @@ -79,7 +79,7 @@ static int dma_set_decrypted(struct device *dev, void *vaddr, size_t size) { if (!force_dma_unencrypted(dev)) return 0; - return set_memory_decrypted((unsigned long)vaddr, 1 << get_order(size)); + return set_memory_decrypted((unsigned long)vaddr, PFN_UP(size)); } static int dma_set_encrypted(struct device *dev, void *vaddr, size_t size) @@ -88,7 +88,7 @@ static int dma_set_encrypted(struct device *dev, void *vaddr, size_t size) if (!force_dma_unencrypted(dev)) return 0; - ret = set_memory_encrypted((unsigned long)vaddr, 1 << get_order(size)); + ret = set_memory_encrypted((unsigned long)vaddr, PFN_UP(size)); if (ret) pr_warn_ratelimited("leaking DMA memory that can't be re-encrypted\n"); return ret; |