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crypto: sha1 - implement base layer for SHA-1

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To reduce the number of copies of boilerplate code throughout
the tree, this patch implements generic glue for the SHA-1
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 (sha1_block_fn)(struct sha1_state *sst, u8 const *src, int blocks)

and pass it to the SHA-1 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 sha1_state is
moved to the base of the struct.

Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
This commit is contained in:
Ard Biesheuvel 2015-04-09 12:55:33 +02:00 committed by Herbert Xu
parent 9c521a200b
commit c4d5b9ffa3
2 changed files with 107 additions and 1 deletions
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2
include/crypto/sha.h
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@ -65,8 +65,8 @@
#define SHA512_H7 0x5be0cd19137e2179ULL
struct sha1_state {
u64 count;
u32 state[SHA1_DIGEST_SIZE / 4];
u64 count;
u8 buffer[SHA1_BLOCK_SIZE];
};

106
include/crypto/sha1_base.h Normal file
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@ -0,0 +1,106 @@
/*
* sha1_base.h - core logic for SHA-1 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 (sha1_block_fn)(struct sha1_state *sst, u8 const *src, int blocks);
static inline int sha1_base_init(struct shash_desc *desc)
{
struct sha1_state *sctx = shash_desc_ctx(desc);
sctx->state[0] = SHA1_H0;
sctx->state[1] = SHA1_H1;
sctx->state[2] = SHA1_H2;
sctx->state[3] = SHA1_H3;
sctx->state[4] = SHA1_H4;
sctx->count = 0;
return 0;
}
static inline int sha1_base_do_update(struct shash_desc *desc,
const u8 *data,
unsigned int len,
sha1_block_fn *block_fn)
{
struct sha1_state *sctx = shash_desc_ctx(desc);
unsigned int partial = sctx->count % SHA1_BLOCK_SIZE;
sctx->count += len;
if (unlikely((partial + len) >= SHA1_BLOCK_SIZE)) {
int blocks;
if (partial) {
int p = SHA1_BLOCK_SIZE - partial;
memcpy(sctx->buffer + partial, data, p);
data += p;
len -= p;
block_fn(sctx, sctx->buffer, 1);
}
blocks = len / SHA1_BLOCK_SIZE;
len %= SHA1_BLOCK_SIZE;
if (blocks) {
block_fn(sctx, data, blocks);
data += blocks * SHA1_BLOCK_SIZE;
}
partial = 0;
}
if (len)
memcpy(sctx->buffer + partial, data, len);
return 0;
}
static inline int sha1_base_do_finalize(struct shash_desc *desc,
sha1_block_fn *block_fn)
{
const int bit_offset = SHA1_BLOCK_SIZE - sizeof(__be64);
struct sha1_state *sctx = shash_desc_ctx(desc);
__be64 *bits = (__be64 *)(sctx->buffer + bit_offset);
unsigned int partial = sctx->count % SHA1_BLOCK_SIZE;
sctx->buffer[partial++] = 0x80;
if (partial > bit_offset) {
memset(sctx->buffer + partial, 0x0, SHA1_BLOCK_SIZE - partial);
partial = 0;
block_fn(sctx, sctx->buffer, 1);
}
memset(sctx->buffer + partial, 0x0, bit_offset - partial);
*bits = cpu_to_be64(sctx->count << 3);
block_fn(sctx, sctx->buffer, 1);
return 0;
}
static inline int sha1_base_finish(struct shash_desc *desc, u8 *out)
{
struct sha1_state *sctx = shash_desc_ctx(desc);
__be32 *digest = (__be32 *)out;
int i;
for (i = 0; i < SHA1_DIGEST_SIZE / sizeof(__be32); i++)
put_unaligned_be32(sctx->state[i], digest++);
*sctx = (struct sha1_state){};
return 0;
}