blob: ecd6b7f34a2d235503af93bc08ef0a123ee932c1 [file] [log] [blame]
// SPDX-License-Identifier: GPL-2.0-or-later
/*
* The AEGIS-256 Authenticated-Encryption Algorithm
*
* Copyright (c) 2017-2018 Ondrej Mosnacek <omosnacek@gmail.com>
* Copyright (C) 2017-2018 Red Hat, Inc. All rights reserved.
*/
#include <crypto/algapi.h>
#include <crypto/internal/aead.h>
#include <crypto/internal/skcipher.h>
#include <crypto/scatterwalk.h>
#include <linux/err.h>
#include <linux/init.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/scatterlist.h>
#include "aegis.h"
#define AEGIS256_NONCE_SIZE 32
#define AEGIS256_STATE_BLOCKS 6
#define AEGIS256_KEY_SIZE 32
#define AEGIS256_MIN_AUTH_SIZE 8
#define AEGIS256_MAX_AUTH_SIZE 16
struct aegis_state {
union aegis_block blocks[AEGIS256_STATE_BLOCKS];
};
struct aegis_ctx {
union aegis_block key[AEGIS256_KEY_SIZE / AEGIS_BLOCK_SIZE];
};
struct aegis256_ops {
int (*skcipher_walk_init)(struct skcipher_walk *walk,
struct aead_request *req, bool atomic);
void (*crypt_chunk)(struct aegis_state *state, u8 *dst,
const u8 *src, unsigned int size);
};
static void crypto_aegis256_update(struct aegis_state *state)
{
union aegis_block tmp;
unsigned int i;
tmp = state->blocks[AEGIS256_STATE_BLOCKS - 1];
for (i = AEGIS256_STATE_BLOCKS - 1; i > 0; i--)
crypto_aegis_aesenc(&state->blocks[i], &state->blocks[i - 1],
&state->blocks[i]);
crypto_aegis_aesenc(&state->blocks[0], &tmp, &state->blocks[0]);
}
static void crypto_aegis256_update_a(struct aegis_state *state,
const union aegis_block *msg)
{
crypto_aegis256_update(state);
crypto_aegis_block_xor(&state->blocks[0], msg);
}
static void crypto_aegis256_update_u(struct aegis_state *state, const void *msg)
{
crypto_aegis256_update(state);
crypto_xor(state->blocks[0].bytes, msg, AEGIS_BLOCK_SIZE);
}
static void crypto_aegis256_init(struct aegis_state *state,
const union aegis_block *key,
const u8 *iv)
{
union aegis_block key_iv[2];
unsigned int i;
key_iv[0] = key[0];
key_iv[1] = key[1];
crypto_xor(key_iv[0].bytes, iv + 0 * AEGIS_BLOCK_SIZE,
AEGIS_BLOCK_SIZE);
crypto_xor(key_iv[1].bytes, iv + 1 * AEGIS_BLOCK_SIZE,
AEGIS_BLOCK_SIZE);
state->blocks[0] = key_iv[0];
state->blocks[1] = key_iv[1];
state->blocks[2] = crypto_aegis_const[1];
state->blocks[3] = crypto_aegis_const[0];
state->blocks[4] = key[0];
state->blocks[5] = key[1];
crypto_aegis_block_xor(&state->blocks[4], &crypto_aegis_const[0]);
crypto_aegis_block_xor(&state->blocks[5], &crypto_aegis_const[1]);
for (i = 0; i < 4; i++) {
crypto_aegis256_update_a(state, &key[0]);
crypto_aegis256_update_a(state, &key[1]);
crypto_aegis256_update_a(state, &key_iv[0]);
crypto_aegis256_update_a(state, &key_iv[1]);
}
}
static void crypto_aegis256_ad(struct aegis_state *state,
const u8 *src, unsigned int size)
{
if (AEGIS_ALIGNED(src)) {
const union aegis_block *src_blk =
(const union aegis_block *)src;
while (size >= AEGIS_BLOCK_SIZE) {
crypto_aegis256_update_a(state, src_blk);
size -= AEGIS_BLOCK_SIZE;
src_blk++;
}
} else {
while (size >= AEGIS_BLOCK_SIZE) {
crypto_aegis256_update_u(state, src);
size -= AEGIS_BLOCK_SIZE;
src += AEGIS_BLOCK_SIZE;
}
}
}
static void crypto_aegis256_encrypt_chunk(struct aegis_state *state, u8 *dst,
const u8 *src, unsigned int size)
{
union aegis_block tmp;
if (AEGIS_ALIGNED(src) && AEGIS_ALIGNED(dst)) {
while (size >= AEGIS_BLOCK_SIZE) {
union aegis_block *dst_blk =
(union aegis_block *)dst;
const union aegis_block *src_blk =
(const union aegis_block *)src;
tmp = state->blocks[2];
crypto_aegis_block_and(&tmp, &state->blocks[3]);
crypto_aegis_block_xor(&tmp, &state->blocks[5]);
crypto_aegis_block_xor(&tmp, &state->blocks[4]);
crypto_aegis_block_xor(&tmp, &state->blocks[1]);
crypto_aegis_block_xor(&tmp, src_blk);
crypto_aegis256_update_a(state, src_blk);
*dst_blk = tmp;
size -= AEGIS_BLOCK_SIZE;
src += AEGIS_BLOCK_SIZE;
dst += AEGIS_BLOCK_SIZE;
}
} else {
while (size >= AEGIS_BLOCK_SIZE) {
tmp = state->blocks[2];
crypto_aegis_block_and(&tmp, &state->blocks[3]);
crypto_aegis_block_xor(&tmp, &state->blocks[5]);
crypto_aegis_block_xor(&tmp, &state->blocks[4]);
crypto_aegis_block_xor(&tmp, &state->blocks[1]);
crypto_xor(tmp.bytes, src, AEGIS_BLOCK_SIZE);
crypto_aegis256_update_u(state, src);
memcpy(dst, tmp.bytes, AEGIS_BLOCK_SIZE);
size -= AEGIS_BLOCK_SIZE;
src += AEGIS_BLOCK_SIZE;
dst += AEGIS_BLOCK_SIZE;
}
}
if (size > 0) {
union aegis_block msg = {};
memcpy(msg.bytes, src, size);
tmp = state->blocks[2];
crypto_aegis_block_and(&tmp, &state->blocks[3]);
crypto_aegis_block_xor(&tmp, &state->blocks[5]);
crypto_aegis_block_xor(&tmp, &state->blocks[4]);
crypto_aegis_block_xor(&tmp, &state->blocks[1]);
crypto_aegis256_update_a(state, &msg);
crypto_aegis_block_xor(&msg, &tmp);
memcpy(dst, msg.bytes, size);
}
}
static void crypto_aegis256_decrypt_chunk(struct aegis_state *state, u8 *dst,
const u8 *src, unsigned int size)
{
union aegis_block tmp;
if (AEGIS_ALIGNED(src) && AEGIS_ALIGNED(dst)) {
while (size >= AEGIS_BLOCK_SIZE) {
union aegis_block *dst_blk =
(union aegis_block *)dst;
const union aegis_block *src_blk =
(const union aegis_block *)src;
tmp = state->blocks[2];
crypto_aegis_block_and(&tmp, &state->blocks[3]);
crypto_aegis_block_xor(&tmp, &state->blocks[5]);
crypto_aegis_block_xor(&tmp, &state->blocks[4]);
crypto_aegis_block_xor(&tmp, &state->blocks[1]);
crypto_aegis_block_xor(&tmp, src_blk);
crypto_aegis256_update_a(state, &tmp);
*dst_blk = tmp;
size -= AEGIS_BLOCK_SIZE;
src += AEGIS_BLOCK_SIZE;
dst += AEGIS_BLOCK_SIZE;
}
} else {
while (size >= AEGIS_BLOCK_SIZE) {
tmp = state->blocks[2];
crypto_aegis_block_and(&tmp, &state->blocks[3]);
crypto_aegis_block_xor(&tmp, &state->blocks[5]);
crypto_aegis_block_xor(&tmp, &state->blocks[4]);
crypto_aegis_block_xor(&tmp, &state->blocks[1]);
crypto_xor(tmp.bytes, src, AEGIS_BLOCK_SIZE);
crypto_aegis256_update_a(state, &tmp);
memcpy(dst, tmp.bytes, AEGIS_BLOCK_SIZE);
size -= AEGIS_BLOCK_SIZE;
src += AEGIS_BLOCK_SIZE;
dst += AEGIS_BLOCK_SIZE;
}
}
if (size > 0) {
union aegis_block msg = {};
memcpy(msg.bytes, src, size);
tmp = state->blocks[2];
crypto_aegis_block_and(&tmp, &state->blocks[3]);
crypto_aegis_block_xor(&tmp, &state->blocks[5]);
crypto_aegis_block_xor(&tmp, &state->blocks[4]);
crypto_aegis_block_xor(&tmp, &state->blocks[1]);
crypto_aegis_block_xor(&msg, &tmp);
memset(msg.bytes + size, 0, AEGIS_BLOCK_SIZE - size);
crypto_aegis256_update_a(state, &msg);
memcpy(dst, msg.bytes, size);
}
}
static void crypto_aegis256_process_ad(struct aegis_state *state,
struct scatterlist *sg_src,
unsigned int assoclen)
{
struct scatter_walk walk;
union aegis_block buf;
unsigned int pos = 0;
scatterwalk_start(&walk, sg_src);
while (assoclen != 0) {
unsigned int size = scatterwalk_clamp(&walk, assoclen);
unsigned int left = size;
void *mapped = scatterwalk_map(&walk);
const u8 *src = (const u8 *)mapped;
if (pos + size >= AEGIS_BLOCK_SIZE) {
if (pos > 0) {
unsigned int fill = AEGIS_BLOCK_SIZE - pos;
memcpy(buf.bytes + pos, src, fill);
crypto_aegis256_update_a(state, &buf);
pos = 0;
left -= fill;
src += fill;
}
crypto_aegis256_ad(state, src, left);
src += left & ~(AEGIS_BLOCK_SIZE - 1);
left &= AEGIS_BLOCK_SIZE - 1;
}
memcpy(buf.bytes + pos, src, left);
pos += left;
assoclen -= size;
scatterwalk_unmap(mapped);
scatterwalk_advance(&walk, size);
scatterwalk_done(&walk, 0, assoclen);
}
if (pos > 0) {
memset(buf.bytes + pos, 0, AEGIS_BLOCK_SIZE - pos);
crypto_aegis256_update_a(state, &buf);
}
}
static void crypto_aegis256_process_crypt(struct aegis_state *state,
struct aead_request *req,
const struct aegis256_ops *ops)
{
struct skcipher_walk walk;
ops->skcipher_walk_init(&walk, req, false);
while (walk.nbytes) {
unsigned int nbytes = walk.nbytes;
if (nbytes < walk.total)
nbytes = round_down(nbytes, walk.stride);
ops->crypt_chunk(state, walk.dst.virt.addr, walk.src.virt.addr,
nbytes);
skcipher_walk_done(&walk, walk.nbytes - nbytes);
}
}
static void crypto_aegis256_final(struct aegis_state *state,
union aegis_block *tag_xor,
u64 assoclen, u64 cryptlen)
{
u64 assocbits = assoclen * 8;
u64 cryptbits = cryptlen * 8;
union aegis_block tmp;
unsigned int i;
tmp.words64[0] = cpu_to_le64(assocbits);
tmp.words64[1] = cpu_to_le64(cryptbits);
crypto_aegis_block_xor(&tmp, &state->blocks[3]);
for (i = 0; i < 7; i++)
crypto_aegis256_update_a(state, &tmp);
for (i = 0; i < AEGIS256_STATE_BLOCKS; i++)
crypto_aegis_block_xor(tag_xor, &state->blocks[i]);
}
static int crypto_aegis256_setkey(struct crypto_aead *aead, const u8 *key,
unsigned int keylen)
{
struct aegis_ctx *ctx = crypto_aead_ctx(aead);
if (keylen != AEGIS256_KEY_SIZE) {
crypto_aead_set_flags(aead, CRYPTO_TFM_RES_BAD_KEY_LEN);
return -EINVAL;
}
memcpy(ctx->key[0].bytes, key, AEGIS_BLOCK_SIZE);
memcpy(ctx->key[1].bytes, key + AEGIS_BLOCK_SIZE,
AEGIS_BLOCK_SIZE);
return 0;
}
static int crypto_aegis256_setauthsize(struct crypto_aead *tfm,
unsigned int authsize)
{
if (authsize > AEGIS256_MAX_AUTH_SIZE)
return -EINVAL;
if (authsize < AEGIS256_MIN_AUTH_SIZE)
return -EINVAL;
return 0;
}
static void crypto_aegis256_crypt(struct aead_request *req,
union aegis_block *tag_xor,
unsigned int cryptlen,
const struct aegis256_ops *ops)
{
struct crypto_aead *tfm = crypto_aead_reqtfm(req);
struct aegis_ctx *ctx = crypto_aead_ctx(tfm);
struct aegis_state state;
crypto_aegis256_init(&state, ctx->key, req->iv);
crypto_aegis256_process_ad(&state, req->src, req->assoclen);
crypto_aegis256_process_crypt(&state, req, ops);
crypto_aegis256_final(&state, tag_xor, req->assoclen, cryptlen);
}
static int crypto_aegis256_encrypt(struct aead_request *req)
{
static const struct aegis256_ops ops = {
.skcipher_walk_init = skcipher_walk_aead_encrypt,
.crypt_chunk = crypto_aegis256_encrypt_chunk,
};
struct crypto_aead *tfm = crypto_aead_reqtfm(req);
union aegis_block tag = {};
unsigned int authsize = crypto_aead_authsize(tfm);
unsigned int cryptlen = req->cryptlen;
crypto_aegis256_crypt(req, &tag, cryptlen, &ops);
scatterwalk_map_and_copy(tag.bytes, req->dst, req->assoclen + cryptlen,
authsize, 1);
return 0;
}
static int crypto_aegis256_decrypt(struct aead_request *req)
{
static const struct aegis256_ops ops = {
.skcipher_walk_init = skcipher_walk_aead_decrypt,
.crypt_chunk = crypto_aegis256_decrypt_chunk,
};
static const u8 zeros[AEGIS256_MAX_AUTH_SIZE] = {};
struct crypto_aead *tfm = crypto_aead_reqtfm(req);
union aegis_block tag;
unsigned int authsize = crypto_aead_authsize(tfm);
unsigned int cryptlen = req->cryptlen - authsize;
scatterwalk_map_and_copy(tag.bytes, req->src, req->assoclen + cryptlen,
authsize, 0);
crypto_aegis256_crypt(req, &tag, cryptlen, &ops);
return crypto_memneq(tag.bytes, zeros, authsize) ? -EBADMSG : 0;
}
static int crypto_aegis256_init_tfm(struct crypto_aead *tfm)
{
return 0;
}
static void crypto_aegis256_exit_tfm(struct crypto_aead *tfm)
{
}
static struct aead_alg crypto_aegis256_alg = {
.setkey = crypto_aegis256_setkey,
.setauthsize = crypto_aegis256_setauthsize,
.encrypt = crypto_aegis256_encrypt,
.decrypt = crypto_aegis256_decrypt,
.init = crypto_aegis256_init_tfm,
.exit = crypto_aegis256_exit_tfm,
.ivsize = AEGIS256_NONCE_SIZE,
.maxauthsize = AEGIS256_MAX_AUTH_SIZE,
.chunksize = AEGIS_BLOCK_SIZE,
.base = {
.cra_blocksize = 1,
.cra_ctxsize = sizeof(struct aegis_ctx),
.cra_alignmask = 0,
.cra_priority = 100,
.cra_name = "aegis256",
.cra_driver_name = "aegis256-generic",
.cra_module = THIS_MODULE,
}
};
static int __init crypto_aegis256_module_init(void)
{
return crypto_register_aead(&crypto_aegis256_alg);
}
static void __exit crypto_aegis256_module_exit(void)
{
crypto_unregister_aead(&crypto_aegis256_alg);
}
module_init(crypto_aegis256_module_init);
module_exit(crypto_aegis256_module_exit);
MODULE_LICENSE("GPL");
MODULE_AUTHOR("Ondrej Mosnacek <omosnacek@gmail.com>");
MODULE_DESCRIPTION("AEGIS-256 AEAD algorithm");
MODULE_ALIAS_CRYPTO("aegis256");
MODULE_ALIAS_CRYPTO("aegis256-generic");