Commit 232c1e8e authored by Ryan Wanner's avatar Ryan Wanner Committed by Herbert Xu
Browse files

crypto: atmel-sha - Add zero length message digest support for hmac 



Add softare padding to hmac-sha digest for zero length messages.
Using the atmel_sha_fill_padding() to fill the buffer with a padded
empty message with a length of the block size.

Create a temporary scatter list from the padded buffer to pass into the
data processing functions.

Signed-off-by: default avatarRyan Wanner <Ryan.Wanner@microchip.com>
Signed-off-by: default avatarHerbert Xu <herbert@gondor.apana.org.au>
parent a4b16dad

drivers/crypto/atmel-sha.c

+30 −4
Original line number Diff line number Diff line
@@ -1948,14 +1948,32 @@ static int atmel_sha_hmac_digest2(struct atmel_sha_dev *dd) 
	struct atmel_sha_reqctx *ctx = ahash_request_ctx(req);

	struct crypto_ahash *tfm = crypto_ahash_reqtfm(req);

	struct atmel_sha_hmac_ctx *hmac = crypto_ahash_ctx(tfm);

	struct scatterlist *sgbuf;

	size_t hs = ctx->hash_size;

	size_t i, num_words = hs / sizeof(u32);

	bool use_dma = false;

	u32 mr;



	/* Special case for empty message. */

	if (!req->nbytes)

		return atmel_sha_complete(dd, -EINVAL); // TODO:

	if (!req->nbytes) {

		req->nbytes = 0;

		ctx->bufcnt = 0;

		ctx->digcnt[0] = 0;

		ctx->digcnt[1] = 0;

		switch (ctx->flags & SHA_FLAGS_ALGO_MASK) {

		case SHA_FLAGS_SHA1:

		case SHA_FLAGS_SHA224:

		case SHA_FLAGS_SHA256:

			atmel_sha_fill_padding(ctx, 64);

			break;



		case SHA_FLAGS_SHA384:

		case SHA_FLAGS_SHA512:

			atmel_sha_fill_padding(ctx, 128);

			break;

		}

		sg_init_one(&dd->tmp, ctx->buffer, ctx->bufcnt);

	}



	/* Check DMA threshold and alignment. */

	if (req->nbytes > ATMEL_SHA_DMA_THRESHOLD &&
@@ -1985,12 +2003,20 @@ static int atmel_sha_hmac_digest2(struct atmel_sha_dev *dd) 


	atmel_sha_write(dd, SHA_CR, SHA_CR_FIRST);



	/* Special case for empty message. */

	if (!req->nbytes) {

		sgbuf = &dd->tmp;

		req->nbytes = ctx->bufcnt;

	} else {

		sgbuf = req->src;

	}



	/* Process data. */

	if (use_dma)

		return atmel_sha_dma_start(dd, req->src, req->nbytes,

		return atmel_sha_dma_start(dd, sgbuf, req->nbytes,

					   atmel_sha_hmac_final_done);



	return atmel_sha_cpu_start(dd, req->src, req->nbytes, false, true,

	return atmel_sha_cpu_start(dd, sgbuf, req->nbytes, false, true,

				   atmel_sha_hmac_final_done);

}