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

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

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

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.

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]

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

[snip]

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

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

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.

+		iv = memcpy(((u8 *)edesc) + alloc_len - ivsize, iv, ivsize);
+
 	edesc->src_nents = src_nents;
 	edesc->dst_nents = dst_nents;
-	edesc->iv_dma = iv_dma;
+	if (ivsize)
+		edesc->iv_dma = dma_map_single(dev, iv, ivsize, DMA_TO_DEVICE);
+	else
+		edesc->iv_dma = 0;
+