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

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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: Ryan Wanner <Ryan.Wanner@microchip.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
This commit is contained in:
Ryan Wanner 2023-03-28 12:56:26 -07:00 committed by Herbert Xu
parent a4b16dad46
commit 232c1e8e19
1 changed files with 30 additions and 4 deletions
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34
drivers/crypto/atmel-sha.c
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@ -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);
}