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SubjectRe: [PATCH 4/4] crypto: qce: If total text size is zero, return pre-computed digest
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On 30/08/2016 17:53, Iaroslav Gridin wrote:
> From: Voker57 <voker57@gmail.com>
>
> If total data amount to hash is zero, we cannot submit it to QCE,
> since it locks up on zero-sized updates. So, return pre-computed
> SHA256/SHA1 hash.
> Signed-off-by: Iaroslav Gridin <voker57@gmail.com>
> ---
> drivers/crypto/qce/sha.c | 27 ++++++++++++++++++++++++---
> 1 file changed, 24 insertions(+), 3 deletions(-)
>
> diff --git a/drivers/crypto/qce/sha.c b/drivers/crypto/qce/sha.c
> index f199f28..c627b5d 100644
> --- a/drivers/crypto/qce/sha.c
> +++ b/drivers/crypto/qce/sha.c
> @@ -80,6 +80,7 @@ static int qce_ahash_async_req_handle(struct crypto_async_request *async_req)
> struct qce_sha_ctx *ctx = crypto_tfm_ctx(async_req->tfm);
> struct qce_alg_template *tmpl = to_ahash_tmpl(async_req->tfm);
> struct qce_device *qce = tmpl->qce;
> + unsigned int digestsize = crypto_ahash_digestsize(crypto_ahash_reqtfm(req));
> unsigned long flags = rctx->flags;
> int ret;
>
> @@ -91,6 +92,29 @@ static int qce_ahash_async_req_handle(struct crypto_async_request *async_req)
> rctx->authklen = AES_KEYSIZE_128;
> }
>
> + if (!req->nbytes) {
> + /* Only way that can happen is if total size of digest is zero
> + * So since QCE gets stuck on zero-sized texts, we return
> + * pre-calculated hash
> + */
> + if (digestsize == SHA1_DIGEST_SIZE) {
> + memcpy(rctx->digest,
> + "\xda\x39\xa3\xee\x5e\x6b\x4b\x0d\x32\x55\xbf\xef\x95\x60\x18\x90\xaf\xd8\x07\x09",
> + SHA1_DIGEST_SIZE);
> + } else if (digestsize == SHA256_DIGEST_SIZE) {
> + memcpy(rctx->digest,
> + "\xe3\xb0\xc4\x42\x98\xfc\x1c\x14\x9a\xfb\xf4\xc8\x99\x6f\xb9\x24\x27\xae\x41\xe4\x64\x9b\x93\x4c\xa4\x95\x99\x1b\x78\x52\xb8\x55",
> + SHA256_DIGEST_SIZE);

Hello

You could use sha1_zero_message_hash/sha256_zero_message_hash declared in crypto/sha.h

Regards

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