Re: [PATCH v3] crypto: talitos - fix ablkcipher for CONFIG_VMAP_STACK

Le 04/01/2019 à 16:24, Horia Geanta a écrit :

On 1/4/2019 5:17 PM, Horia Geanta wrote:

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On 12/21/2018 10:07 AM, Christophe Leroy wrote:
[snip]

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IV cannot be on stack when CONFIG_VMAP_STACK is selected because the stack
cannot be DMA mapped anymore.
This looks better, thanks.

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This patch copies the IV into the extended descriptor when iv is not
a valid linear address.

Though I am not sure the checks in place are enough.

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Fixes: 4de9d0b547b9 ("crypto: talitos - Add ablkcipher algorithms")
Cc: stable@vger.kernel.org
Signed-off-by: Christophe Leroy <redacted>
---
  v3: Using struct edesc buffer.

  v2: Using per-request context.

[snip]

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+	if (ivsize && !virt_addr_valid(iv))
+		alloc_len += ivsize;

[snip]

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+	if (ivsize && !virt_addr_valid(iv))

A more precise condition would be (!is_vmalloc_addr || is_vmalloc_addr(iv))

Sorry for the typo, I meant:
(!virt_addr_valid(iv) || is_vmalloc_addr(iv))

As far as I know, virt_addr_valid() means the address is in the linear 
memory space. So it cannot be a vmalloc_addr if it is a linear space 
addr, can it ?

At least, it is that way on powerpc which is the arch embedding the 
talitos crypto engine. virt_addr_valid() means we are under max_pfn, 
while VMALLOC_START is above max_pfn.

Christophe

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It matches the checks in debug_dma_map_single() helper, though I am not sure
they are enough to rule out all exceptions of DMA API.