linux/crypto/aegis256.c
Eric Biggers 0f533e67d2 crypto: aegis - fix handling chunked inputs
The generic AEGIS implementations all fail the improved AEAD tests
because they produce the wrong result with some data layouts.  The issue
is that they assume that if the skcipher_walk API gives 'nbytes' not
aligned to the walksize (a.k.a. walk.stride), then it is the end of the
data.  In fact, this can happen before the end.  Fix them.

Fixes: f606a88e58 ("crypto: aegis - Add generic AEGIS AEAD implementations")
Cc: <stable@vger.kernel.org> # v4.18+
Cc: Ondrej Mosnacek <omosnace@redhat.com>
Signed-off-by: Eric Biggers <ebiggers@google.com>
Reviewed-by: Ondrej Mosnacek <omosnace@redhat.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
2019-02-08 15:30:08 +08:00

474 lines
12 KiB
C

// 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");