/* * 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. * * This program is free software; you can redistribute it and/or modify it * under the terms of the GNU General Public License as published by the Free * Software Foundation; either version 2 of the License, or (at your option) * any later version. */ #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; u8 *src, *dst; unsigned int chunksize; ops->skcipher_walk_init(&walk, req, false); while (walk.nbytes) { src = walk.src.virt.addr; dst = walk.dst.virt.addr; chunksize = walk.nbytes; ops->crypt_chunk(state, dst, src, chunksize); skcipher_walk_done(&walk, 0); } } 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");