crypto: aegis - Add generic AEGIS AEAD implementations

This patch adds the generic implementation of the AEGIS family of AEAD
algorithms (AEGIS-128, AEGIS-128L, and AEGIS-256). The original
authors of AEGIS are Hongjun Wu and Bart Preneel.

At the time of writing, AEGIS is one of the finalists in CAESAR, an
open competition intended to select a portfolio of alternatives to
the problematic AES-GCM:

https://competitions.cr.yp.to/caesar-submissions.html
https://competitions.cr.yp.to/round3/aegisv11.pdf

Signed-off-by: Ondrej Mosnacek <omosnacek@gmail.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

1 files changed, 478 insertions, 0 deletions

diff --git a/crypto/aegis256.c b/crypto/aegis256.c
new file mode 100644
index 000000000000..a489d741d33a
--- /dev/null
+++ b/crypto/aegis256.c
@@ -0,0 +1,478 @@
+/*
+ * 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_flags = CRYPTO_ALG_TYPE_AEAD,
+		.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");