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crypto: sha256-generic - move to generic glue implementation
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This updates the generic SHA-256 implementation to use the
new shared SHA-256 glue code.

It also implements a .finup hook crypto_sha256_finup() and exports
it to other modules. The import and export() functions and the
.statesize member are dropped, since the default implementation
is perfectly suitable for this module.

Signed-off-by: Ard Biesheuvel <[email protected]>
Signed-off-by: Herbert Xu <[email protected]>
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@herbertx
Ard Biesheuvel authored and herbertx committed Apr 10, 2015
1 parent 7c71f0f commit a2e5ba4
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Showing 2 changed files with 23 additions and 113 deletions.
133 changes: 20 additions & 113 deletions crypto/sha256_generic.c
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Original file line number Diff line number Diff line change
Expand Up @@ -23,6 +23,7 @@
#include <linux/mm.h>
#include <linux/types.h>
#include <crypto/sha.h>
#include <crypto/sha256_base.h>
#include <asm/byteorder.h>
#include <asm/unaligned.h>

Expand Down Expand Up @@ -214,138 +215,43 @@ static void sha256_transform(u32 *state, const u8 *input)
memzero_explicit(W, 64 * sizeof(u32));
}

static int sha224_init(struct shash_desc *desc)
static void sha256_generic_block_fn(struct sha256_state *sst, u8 const *src,
int blocks)
{
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 int sha256_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;
while (blocks--) {
sha256_transform(sst->state, src);
src += SHA256_BLOCK_SIZE;
}
}

int crypto_sha256_update(struct shash_desc *desc, const u8 *data,
unsigned int len)
{
struct sha256_state *sctx = shash_desc_ctx(desc);
unsigned int partial, done;
const u8 *src;

partial = sctx->count & 0x3f;
sctx->count += len;
done = 0;
src = data;

if ((partial + len) > 63) {
if (partial) {
done = -partial;
memcpy(sctx->buf + partial, data, done + 64);
src = sctx->buf;
}

do {
sha256_transform(sctx->state, src);
done += 64;
src = data + done;
} while (done + 63 < len);

partial = 0;
}
memcpy(sctx->buf + partial, src, len - done);

return 0;
return sha256_base_do_update(desc, data, len, sha256_generic_block_fn);
}
EXPORT_SYMBOL(crypto_sha256_update);

static int sha256_final(struct shash_desc *desc, u8 *out)
{
struct sha256_state *sctx = shash_desc_ctx(desc);
__be32 *dst = (__be32 *)out;
__be64 bits;
unsigned int index, pad_len;
int i;
static const u8 padding[64] = { 0x80, };

/* Save number of bits */
bits = cpu_to_be64(sctx->count << 3);

/* Pad out to 56 mod 64. */
index = sctx->count & 0x3f;
pad_len = (index < 56) ? (56 - index) : ((64+56) - index);
crypto_sha256_update(desc, padding, pad_len);

/* Append length (before padding) */
crypto_sha256_update(desc, (const u8 *)&bits, sizeof(bits));

/* Store state in digest */
for (i = 0; i < 8; i++)
dst[i] = cpu_to_be32(sctx->state[i]);

/* Zeroize sensitive information. */
memset(sctx, 0, sizeof(*sctx));

return 0;
sha256_base_do_finalize(desc, sha256_generic_block_fn);
return sha256_base_finish(desc, out);
}

static int sha224_final(struct shash_desc *desc, u8 *hash)
int crypto_sha256_finup(struct shash_desc *desc, const u8 *data,
unsigned int len, u8 *hash)
{
u8 D[SHA256_DIGEST_SIZE];

sha256_final(desc, D);

memcpy(hash, D, SHA224_DIGEST_SIZE);
memzero_explicit(D, SHA256_DIGEST_SIZE);

return 0;
}

static int sha256_export(struct shash_desc *desc, void *out)
{
struct sha256_state *sctx = shash_desc_ctx(desc);

memcpy(out, sctx, sizeof(*sctx));
return 0;
}

static int sha256_import(struct shash_desc *desc, const void *in)
{
struct sha256_state *sctx = shash_desc_ctx(desc);

memcpy(sctx, in, sizeof(*sctx));
return 0;
sha256_base_do_update(desc, data, len, sha256_generic_block_fn);
return sha256_final(desc, hash);
}
EXPORT_SYMBOL(crypto_sha256_finup);

static struct shash_alg sha256_algs[2] = { {
.digestsize = SHA256_DIGEST_SIZE,
.init = sha256_init,
.init = sha256_base_init,
.update = crypto_sha256_update,
.final = sha256_final,
.export = sha256_export,
.import = sha256_import,
.finup = crypto_sha256_finup,
.descsize = sizeof(struct sha256_state),
.statesize = sizeof(struct sha256_state),
.base = {
.cra_name = "sha256",
.cra_driver_name= "sha256-generic",
Expand All @@ -355,9 +261,10 @@ static struct shash_alg sha256_algs[2] = { {
}
}, {
.digestsize = SHA224_DIGEST_SIZE,
.init = sha224_init,
.init = sha224_base_init,
.update = crypto_sha256_update,
.final = sha224_final,
.final = sha256_final,
.finup = crypto_sha256_finup,
.descsize = sizeof(struct sha256_state),
.base = {
.cra_name = "sha224",
Expand Down
3 changes: 3 additions & 0 deletions include/crypto/sha.h
View file
Original file line number Diff line number Diff line change
Expand Up @@ -93,6 +93,9 @@ extern int crypto_sha1_finup(struct shash_desc *desc, const u8 *data,
extern int crypto_sha256_update(struct shash_desc *desc, const u8 *data,
unsigned int len);

extern int crypto_sha256_finup(struct shash_desc *desc, const u8 *data,
unsigned int len, u8 *hash);

extern int crypto_sha512_update(struct shash_desc *desc, const u8 *data,
unsigned int len);
#endif

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