Donate to e Foundation | Murena handsets with /e/OS | Own a part of Murena! Learn more

Commit 11b8d5ef authored by Ard Biesheuvel's avatar Ard Biesheuvel Committed by Herbert Xu
Browse files

crypto: sha256 - implement base layer for SHA-256 



To reduce the number of copies of boilerplate code throughout
the tree, this patch implements generic glue for the SHA-256
algorithm. This allows a specific arch or hardware implementation
to only implement the special handling that it needs.

The users need to supply an implementation of

  void (sha256_block_fn)(struct sha256_state *sst, u8 const *src, int blocks)

and pass it to the SHA-256 base functions. For easy casting between the
prototype above and existing block functions that take a 'u32 state[]'
as their first argument, the 'state' member of struct sha256_state is
moved to the base of the struct.

Signed-off-by: default avatarArd Biesheuvel <ard.biesheuvel@linaro.org>
Signed-off-by: default avatarHerbert Xu <herbert@gondor.apana.org.au>
parent c4d5b9ff

include/crypto/sha.h

+1 −1
Original line number Diff line number Diff line
@@ -71,8 +71,8 @@ struct sha1_state { 
};



struct sha256_state {

	u64 count;

	u32 state[SHA256_DIGEST_SIZE / 4];

	u64 count;

	u8 buf[SHA256_BLOCK_SIZE];

};

include/crypto/sha256_base.h

0 → 100644
+128 −0
Original line number Diff line number Diff line 
/*

 * sha256_base.h - core logic for SHA-256 implementations

 *

 * Copyright (C) 2015 Linaro Ltd <ard.biesheuvel@linaro.org>

 *

 * This program is free software; you can redistribute it and/or modify

 * it under the terms of the GNU General Public License version 2 as

 * published by the Free Software Foundation.

 */



#include <crypto/internal/hash.h>

#include <crypto/sha.h>

#include <linux/crypto.h>

#include <linux/module.h>



#include <asm/unaligned.h>



typedef void (sha256_block_fn)(struct sha256_state *sst, u8 const *src,

			       int blocks);



static inline int sha224_base_init(struct shash_desc *desc)

{

	struct sha256_state *sctx = shash_desc_ctx(desc);



	sctx->state[0] = SHA224_H0;

	sctx->state[1] = SHA224_H1;

	sctx->state[2] = SHA224_H2;

	sctx->state[3] = SHA224_H3;

	sctx->state[4] = SHA224_H4;

	sctx->state[5] = SHA224_H5;

	sctx->state[6] = SHA224_H6;

	sctx->state[7] = SHA224_H7;

	sctx->count = 0;



	return 0;

}



static inline int sha256_base_init(struct shash_desc *desc)

{

	struct sha256_state *sctx = shash_desc_ctx(desc);



	sctx->state[0] = SHA256_H0;

	sctx->state[1] = SHA256_H1;

	sctx->state[2] = SHA256_H2;

	sctx->state[3] = SHA256_H3;

	sctx->state[4] = SHA256_H4;

	sctx->state[5] = SHA256_H5;

	sctx->state[6] = SHA256_H6;

	sctx->state[7] = SHA256_H7;

	sctx->count = 0;



	return 0;

}



static inline int sha256_base_do_update(struct shash_desc *desc,

					const u8 *data,

					unsigned int len,

					sha256_block_fn *block_fn)

{

	struct sha256_state *sctx = shash_desc_ctx(desc);

	unsigned int partial = sctx->count % SHA256_BLOCK_SIZE;



	sctx->count += len;



	if (unlikely((partial + len) >= SHA256_BLOCK_SIZE)) {

		int blocks;



		if (partial) {

			int p = SHA256_BLOCK_SIZE - partial;



			memcpy(sctx->buf + partial, data, p);

			data += p;

			len -= p;



			block_fn(sctx, sctx->buf, 1);

		}



		blocks = len / SHA256_BLOCK_SIZE;

		len %= SHA256_BLOCK_SIZE;



		if (blocks) {

			block_fn(sctx, data, blocks);

			data += blocks * SHA256_BLOCK_SIZE;

		}

		partial = 0;

	}

	if (len)

		memcpy(sctx->buf + partial, data, len);



	return 0;

}



static inline int sha256_base_do_finalize(struct shash_desc *desc,

					  sha256_block_fn *block_fn)

{

	const int bit_offset = SHA256_BLOCK_SIZE - sizeof(__be64);

	struct sha256_state *sctx = shash_desc_ctx(desc);

	__be64 *bits = (__be64 *)(sctx->buf + bit_offset);

	unsigned int partial = sctx->count % SHA256_BLOCK_SIZE;



	sctx->buf[partial++] = 0x80;

	if (partial > bit_offset) {

		memset(sctx->buf + partial, 0x0, SHA256_BLOCK_SIZE - partial);

		partial = 0;



		block_fn(sctx, sctx->buf, 1);

	}



	memset(sctx->buf + partial, 0x0, bit_offset - partial);

	*bits = cpu_to_be64(sctx->count << 3);

	block_fn(sctx, sctx->buf, 1);



	return 0;

}



static inline int sha256_base_finish(struct shash_desc *desc, u8 *out)

{

	unsigned int digest_size = crypto_shash_digestsize(desc->tfm);

	struct sha256_state *sctx = shash_desc_ctx(desc);

	__be32 *digest = (__be32 *)out;

	int i;



	for (i = 0; digest_size > 0; i++, digest_size -= sizeof(__be32))

		put_unaligned_be32(sctx->state[i], digest++);



	*sctx = (struct sha256_state){};

	return 0;

}