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");