crypto: arm64/sha1-ce - correct digest for empty data in finup

commit 1d4aaf16defa86d2665ae7db0259d6cb07e2091f upstream.

The sha1-ce finup implementation for ARM64 produces wrong digest
for empty input (len=0). Expected: da39a3ee..., result: 67452301...
(initial value of SHA internal state). The error is in sha1_ce_finup:
for empty data `finalize` will be 1, so the code is relying on
sha1_ce_transform to make the final round. However, in
sha1_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: 07eb54d306f4 ("crypto: arm64/sha1-ce - move SHA-1 ARMv8 implementation to base layer")
Cc: stable@vger.kernel.org
Signed-off-by: Elena Petrova <lenaptr@google.com>
Reviewed-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/arch/arm64/crypto/sha1-ce-glue.c b/arch/arm64/crypto/sha1-ce-glue.c
index efbeb3e0dcfb048099095a971512d8a9a1f62595..70568e6db77b78ed189d7478c3f2442d2052db2b 100644 (file)
--- a/arch/arm64/crypto/sha1-ce-glue.c
+++ b/arch/arm64/crypto/sha1-ce-glue.c
@@ -54,7 +54,7 @@ static int sha1_ce_finup(struct shash_desc *desc, const u8 *data,
                         unsigned int len, u8 *out)
 {
        struct sha1_ce_state *sctx = shash_desc_ctx(desc);
-       bool finalize = !sctx->sst.count && !(len % SHA1_BLOCK_SIZE);
+       bool finalize = !sctx->sst.count && !(len % SHA1_BLOCK_SIZE) && len;
 
        if (!may_use_simd())
                return crypto_sha1_finup(desc, data, len, out);