forked from luck/tmp_suning_uos_patched
crypto: salsa20-generic - cleanup and convert to skcipher API
Convert salsa20-generic from the deprecated "blkcipher" API to the "skcipher" API, in the process fixing it up to be thread-safe (as the crypto API expects) by maintaining each request's state separately from the transform context. Also remove the unnecessary cra_alignmask and tighten validation of the key size by accepting only 16 or 32 bytes, not anything in between. These changes bring the code close to the way chacha20-generic does things, so hopefully it will be easier to maintain in the future. However, the way Salsa20 interprets the IV is still slightly different; that was not changed. Signed-off-by: Eric Biggers <ebiggers@google.com> Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
This commit is contained in:
Eric Biggers
Herbert Xu
parent
148b974dee
commit
b62b3db76f
|
|
@ -19,49 +19,27 @@
|
|||
*
|
||||
*/
|
||||
|
||||
#include <linux/init.h>
|
||||
#include <asm/unaligned.h>
|
||||
#include <crypto/internal/skcipher.h>
|
||||
#include <linux/module.h>
|
||||
#include <linux/errno.h>
|
||||
#include <linux/crypto.h>
|
||||
#include <linux/types.h>
|
||||
#include <linux/bitops.h>
|
||||
#include <crypto/algapi.h>
|
||||
#include <asm/byteorder.h>
|
||||
|
||||
#define SALSA20_IV_SIZE 8U
|
||||
#define SALSA20_MIN_KEY_SIZE 16U
|
||||
#define SALSA20_MAX_KEY_SIZE 32U
|
||||
#define SALSA20_IV_SIZE 8
|
||||
#define SALSA20_MIN_KEY_SIZE 16
|
||||
#define SALSA20_MAX_KEY_SIZE 32
|
||||
#define SALSA20_BLOCK_SIZE 64
|
||||
|
||||
/*
|
||||
* Start of code taken from D. J. Bernstein's reference implementation.
|
||||
* With some modifications and optimizations made to suit our needs.
|
||||
*/
|
||||
|
||||
/*
|
||||
salsa20-ref.c version 20051118
|
||||
D. J. Bernstein
|
||||
Public domain.
|
||||
*/
|
||||
|
||||
#define U32TO8_LITTLE(p, v) \
|
||||
{ (p)[0] = (v >> 0) & 0xff; (p)[1] = (v >> 8) & 0xff; \
|
||||
(p)[2] = (v >> 16) & 0xff; (p)[3] = (v >> 24) & 0xff; }
|
||||
#define U8TO32_LITTLE(p) \
|
||||
(((u32)((p)[0]) ) | ((u32)((p)[1]) << 8) | \
|
||||
((u32)((p)[2]) << 16) | ((u32)((p)[3]) << 24) )
|
||||
|
||||
struct salsa20_ctx
|
||||
{
|
||||
u32 input[16];
|
||||
struct salsa20_ctx {
|
||||
u32 initial_state[16];
|
||||
};
|
||||
|
||||
static void salsa20_wordtobyte(u8 output[64], const u32 input[16])
|
||||
static void salsa20_block(u32 *state, __le32 *stream)
|
||||
{
|
||||
u32 x[16];
|
||||
int i;
|
||||
|
||||
memcpy(x, input, sizeof(x));
|
||||
for (i = 20; i > 0; i -= 2) {
|
||||
memcpy(x, state, sizeof(x));
|
||||
|
||||
for (i = 0; i < 20; i += 2) {
|
||||
x[ 4] ^= rol32((x[ 0] + x[12]), 7);
|
||||
x[ 8] ^= rol32((x[ 4] + x[ 0]), 9);
|
||||
x[12] ^= rol32((x[ 8] + x[ 4]), 13);
|
||||
|
|
@ -95,145 +73,135 @@ static void salsa20_wordtobyte(u8 output[64], const u32 input[16])
|
|||
x[14] ^= rol32((x[13] + x[12]), 13);
|
||||
x[15] ^= rol32((x[14] + x[13]), 18);
|
||||
}
|
||||
for (i = 0; i < 16; ++i)
|
||||
x[i] += input[i];
|
||||
for (i = 0; i < 16; ++i)
|
||||
U32TO8_LITTLE(output + 4 * i,x[i]);
|
||||
|
||||
for (i = 0; i < 16; i++)
|
||||
stream[i] = cpu_to_le32(x[i] + state[i]);
|
||||
|
||||
if (++state[8] == 0)
|
||||
state[9]++;
|
||||
}
|
||||
|
||||
static const char sigma[16] = "expand 32-byte k";
|
||||
static const char tau[16] = "expand 16-byte k";
|
||||
|
||||
static void salsa20_keysetup(struct salsa20_ctx *ctx, const u8 *k, u32 kbytes)
|
||||
static void salsa20_docrypt(u32 *state, u8 *dst, const u8 *src,
|
||||
unsigned int bytes)
|
||||
{
|
||||
const char *constants;
|
||||
|
||||
ctx->input[1] = U8TO32_LITTLE(k + 0);
|
||||
ctx->input[2] = U8TO32_LITTLE(k + 4);
|
||||
ctx->input[3] = U8TO32_LITTLE(k + 8);
|
||||
ctx->input[4] = U8TO32_LITTLE(k + 12);
|
||||
if (kbytes == 32) { /* recommended */
|
||||
k += 16;
|
||||
constants = sigma;
|
||||
} else { /* kbytes == 16 */
|
||||
constants = tau;
|
||||
}
|
||||
ctx->input[11] = U8TO32_LITTLE(k + 0);
|
||||
ctx->input[12] = U8TO32_LITTLE(k + 4);
|
||||
ctx->input[13] = U8TO32_LITTLE(k + 8);
|
||||
ctx->input[14] = U8TO32_LITTLE(k + 12);
|
||||
ctx->input[0] = U8TO32_LITTLE(constants + 0);
|
||||
ctx->input[5] = U8TO32_LITTLE(constants + 4);
|
||||
ctx->input[10] = U8TO32_LITTLE(constants + 8);
|
||||
ctx->input[15] = U8TO32_LITTLE(constants + 12);
|
||||
}
|
||||
|
||||
static void salsa20_ivsetup(struct salsa20_ctx *ctx, const u8 *iv)
|
||||
{
|
||||
ctx->input[6] = U8TO32_LITTLE(iv + 0);
|
||||
ctx->input[7] = U8TO32_LITTLE(iv + 4);
|
||||
ctx->input[8] = 0;
|
||||
ctx->input[9] = 0;
|
||||
}
|
||||
|
||||
static void salsa20_encrypt_bytes(struct salsa20_ctx *ctx, u8 *dst,
|
||||
const u8 *src, unsigned int bytes)
|
||||
{
|
||||
u8 buf[64];
|
||||
__le32 stream[SALSA20_BLOCK_SIZE / sizeof(__le32)];
|
||||
|
||||
if (dst != src)
|
||||
memcpy(dst, src, bytes);
|
||||
|
||||
while (bytes) {
|
||||
salsa20_wordtobyte(buf, ctx->input);
|
||||
|
||||
ctx->input[8]++;
|
||||
if (!ctx->input[8])
|
||||
ctx->input[9]++;
|
||||
|
||||
if (bytes <= 64) {
|
||||
crypto_xor(dst, buf, bytes);
|
||||
return;
|
||||
}
|
||||
|
||||
crypto_xor(dst, buf, 64);
|
||||
bytes -= 64;
|
||||
dst += 64;
|
||||
while (bytes >= SALSA20_BLOCK_SIZE) {
|
||||
salsa20_block(state, stream);
|
||||
crypto_xor(dst, (const u8 *)stream, SALSA20_BLOCK_SIZE);
|
||||
bytes -= SALSA20_BLOCK_SIZE;
|
||||
dst += SALSA20_BLOCK_SIZE;
|
||||
}
|
||||
if (bytes) {
|
||||
salsa20_block(state, stream);
|
||||
crypto_xor(dst, (const u8 *)stream, bytes);
|
||||
}
|
||||
}
|
||||
|
||||
/*
|
||||
* End of code taken from D. J. Bernstein's reference implementation.
|
||||
*/
|
||||
|
||||
static int setkey(struct crypto_tfm *tfm, const u8 *key,
|
||||
unsigned int keysize)
|
||||
static void salsa20_init(u32 *state, const struct salsa20_ctx *ctx,
|
||||
const u8 *iv)
|
||||
{
|
||||
struct salsa20_ctx *ctx = crypto_tfm_ctx(tfm);
|
||||
salsa20_keysetup(ctx, key, keysize);
|
||||
memcpy(state, ctx->initial_state, sizeof(ctx->initial_state));
|
||||
state[6] = get_unaligned_le32(iv + 0);
|
||||
state[7] = get_unaligned_le32(iv + 4);
|
||||
}
|
||||
|
||||
static int salsa20_setkey(struct crypto_skcipher *tfm, const u8 *key,
|
||||
unsigned int keysize)
|
||||
{
|
||||
static const char sigma[16] = "expand 32-byte k";
|
||||
static const char tau[16] = "expand 16-byte k";
|
||||
struct salsa20_ctx *ctx = crypto_skcipher_ctx(tfm);
|
||||
const char *constants;
|
||||
|
||||
if (keysize != SALSA20_MIN_KEY_SIZE &&
|
||||
keysize != SALSA20_MAX_KEY_SIZE)
|
||||
return -EINVAL;
|
||||
|
||||
ctx->initial_state[1] = get_unaligned_le32(key + 0);
|
||||
ctx->initial_state[2] = get_unaligned_le32(key + 4);
|
||||
ctx->initial_state[3] = get_unaligned_le32(key + 8);
|
||||
ctx->initial_state[4] = get_unaligned_le32(key + 12);
|
||||
if (keysize == 32) { /* recommended */
|
||||
key += 16;
|
||||
constants = sigma;
|
||||
} else { /* keysize == 16 */
|
||||
constants = tau;
|
||||
}
|
||||
ctx->initial_state[11] = get_unaligned_le32(key + 0);
|
||||
ctx->initial_state[12] = get_unaligned_le32(key + 4);
|
||||
ctx->initial_state[13] = get_unaligned_le32(key + 8);
|
||||
ctx->initial_state[14] = get_unaligned_le32(key + 12);
|
||||
ctx->initial_state[0] = get_unaligned_le32(constants + 0);
|
||||
ctx->initial_state[5] = get_unaligned_le32(constants + 4);
|
||||
ctx->initial_state[10] = get_unaligned_le32(constants + 8);
|
||||
ctx->initial_state[15] = get_unaligned_le32(constants + 12);
|
||||
|
||||
/* space for the nonce; it will be overridden for each request */
|
||||
ctx->initial_state[6] = 0;
|
||||
ctx->initial_state[7] = 0;
|
||||
|
||||
/* initial block number */
|
||||
ctx->initial_state[8] = 0;
|
||||
ctx->initial_state[9] = 0;
|
||||
|
||||
return 0;
|
||||
}
|
||||
|
||||
static int encrypt(struct blkcipher_desc *desc,
|
||||
struct scatterlist *dst, struct scatterlist *src,
|
||||
unsigned int nbytes)
|
||||
static int salsa20_crypt(struct skcipher_request *req)
|
||||
{
|
||||
struct blkcipher_walk walk;
|
||||
struct crypto_blkcipher *tfm = desc->tfm;
|
||||
struct salsa20_ctx *ctx = crypto_blkcipher_ctx(tfm);
|
||||
struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(req);
|
||||
const struct salsa20_ctx *ctx = crypto_skcipher_ctx(tfm);
|
||||
struct skcipher_walk walk;
|
||||
u32 state[16];
|
||||
int err;
|
||||
|
||||
blkcipher_walk_init(&walk, dst, src, nbytes);
|
||||
err = blkcipher_walk_virt_block(desc, &walk, 64);
|
||||
err = skcipher_walk_virt(&walk, req, true);
|
||||
|
||||
salsa20_ivsetup(ctx, walk.iv);
|
||||
salsa20_init(state, ctx, walk.iv);
|
||||
|
||||
while (walk.nbytes >= 64) {
|
||||
salsa20_encrypt_bytes(ctx, walk.dst.virt.addr,
|
||||
walk.src.virt.addr,
|
||||
walk.nbytes - (walk.nbytes % 64));
|
||||
err = blkcipher_walk_done(desc, &walk, walk.nbytes % 64);
|
||||
}
|
||||
while (walk.nbytes > 0) {
|
||||
unsigned int nbytes = walk.nbytes;
|
||||
|
||||
if (walk.nbytes) {
|
||||
salsa20_encrypt_bytes(ctx, walk.dst.virt.addr,
|
||||
walk.src.virt.addr, walk.nbytes);
|
||||
err = blkcipher_walk_done(desc, &walk, 0);
|
||||
if (nbytes < walk.total)
|
||||
nbytes = round_down(nbytes, walk.stride);
|
||||
|
||||
salsa20_docrypt(state, walk.dst.virt.addr, walk.src.virt.addr,
|
||||
nbytes);
|
||||
err = skcipher_walk_done(&walk, walk.nbytes - nbytes);
|
||||
}
|
||||
|
||||
return err;
|
||||
}
|
||||
|
||||
static struct crypto_alg alg = {
|
||||
.cra_name = "salsa20",
|
||||
.cra_driver_name = "salsa20-generic",
|
||||
.cra_priority = 100,
|
||||
.cra_flags = CRYPTO_ALG_TYPE_BLKCIPHER,
|
||||
.cra_type = &crypto_blkcipher_type,
|
||||
.cra_blocksize = 1,
|
||||
.cra_ctxsize = sizeof(struct salsa20_ctx),
|
||||
.cra_alignmask = 3,
|
||||
.cra_module = THIS_MODULE,
|
||||
.cra_u = {
|
||||
.blkcipher = {
|
||||
.setkey = setkey,
|
||||
.encrypt = encrypt,
|
||||
.decrypt = encrypt,
|
||||
.min_keysize = SALSA20_MIN_KEY_SIZE,
|
||||
.max_keysize = SALSA20_MAX_KEY_SIZE,
|
||||
.ivsize = SALSA20_IV_SIZE,
|
||||
}
|
||||
}
|
||||
static struct skcipher_alg alg = {
|
||||
.base.cra_name = "salsa20",
|
||||
.base.cra_driver_name = "salsa20-generic",
|
||||
.base.cra_priority = 100,
|
||||
.base.cra_blocksize = 1,
|
||||
.base.cra_ctxsize = sizeof(struct salsa20_ctx),
|
||||
.base.cra_module = THIS_MODULE,
|
||||
|
||||
.min_keysize = SALSA20_MIN_KEY_SIZE,
|
||||
.max_keysize = SALSA20_MAX_KEY_SIZE,
|
||||
.ivsize = SALSA20_IV_SIZE,
|
||||
.chunksize = SALSA20_BLOCK_SIZE,
|
||||
.setkey = salsa20_setkey,
|
||||
.encrypt = salsa20_crypt,
|
||||
.decrypt = salsa20_crypt,
|
||||
};
|
||||
|
||||
static int __init salsa20_generic_mod_init(void)
|
||||
{
|
||||
return crypto_register_alg(&alg);
|
||||
return crypto_register_skcipher(&alg);
|
||||
}
|
||||
|
||||
static void __exit salsa20_generic_mod_fini(void)
|
||||
{
|
||||
crypto_unregister_alg(&alg);
|
||||
crypto_unregister_skcipher(&alg);
|
||||
}
|
||||
|
||||
module_init(salsa20_generic_mod_init);
|
||||
|
|
|
|||
Loading…
Reference in New Issue
Block a user