From: Elena Petrova <lena...@google.com>

commit 6bd934de1e393466b319d29c4427598fda096c57 upstream.

The sha256-ce finup implementation for ARM64 produces wrong digest
for empty input (len=0). Expected: the actual digest, result: initial
value of SHA internal state. The error is in sha256_ce_finup:
for empty data `finalize` will be 1, so the code is relying on
sha2_ce_transform to make the final round. However, in
sha256_base_do_update, the block function will not be called when
len == 0.

Fix it by setting finalize to 0 if data is empty.

Fixes: 03802f6a80b3a ("crypto: arm64/sha2-ce - move SHA-224/256 ARMv8 
implementation to base layer")
Cc: sta...@vger.kernel.org
Signed-off-by: Elena Petrova <lena...@google.com>
Reviewed-by: Ard Biesheuvel <ard.biesheu...@linaro.org>
Signed-off-by: Herbert Xu <herb...@gondor.apana.org.au>
Signed-off-by: Greg Kroah-Hartman <gre...@linuxfoundation.org>

---
 arch/arm64/crypto/sha2-ce-glue.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

--- a/arch/arm64/crypto/sha2-ce-glue.c
+++ b/arch/arm64/crypto/sha2-ce-glue.c
@@ -57,7 +57,7 @@ static int sha256_ce_finup(struct shash_
                           unsigned int len, u8 *out)
 {
        struct sha256_ce_state *sctx = shash_desc_ctx(desc);
-       bool finalize = !sctx->sst.count && !(len % SHA256_BLOCK_SIZE);
+       bool finalize = !sctx->sst.count && !(len % SHA256_BLOCK_SIZE) && len;
 
        if (!crypto_simd_usable()) {
                if (len)


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