authenc.c

/*
 * Authenc: Simple AEAD wrapper for IPsec
 *
 * Copyright (c) 2007 Herbert Xu <herbert@gondor.apana.org.au>
 *
 * 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/aead.h>
#include <crypto/internal/hash.h>
#include <crypto/internal/skcipher.h>
#include <crypto/authenc.h>
#include <crypto/scatterwalk.h>
#include <linux/err.h>
#include <linux/init.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/rtnetlink.h>
#include <linux/slab.h>
#include <linux/spinlock.h>

struct authenc_instance_ctx {
	struct crypto_spawn auth;
	struct crypto_skcipher_spawn enc;
};

struct crypto_authenc_ctx {
	spinlock_t auth_lock;
	struct crypto_hash *auth;
	struct crypto_ablkcipher *enc;
};

static int crypto_authenc_setkey(struct crypto_aead *authenc, const u8 *key,
				 unsigned int keylen)
{
	unsigned int authkeylen;
	unsigned int enckeylen;
	struct crypto_authenc_ctx *ctx = crypto_aead_ctx(authenc);
	struct crypto_hash *auth = ctx->auth;
	struct crypto_ablkcipher *enc = ctx->enc;
	struct rtattr *rta = (void *)key;
	struct crypto_authenc_key_param *param;
	int err = -EINVAL;

	if (!RTA_OK(rta, keylen))
		goto badkey;
	if (rta->rta_type != CRYPTO_AUTHENC_KEYA_PARAM)
		goto badkey;
	if (RTA_PAYLOAD(rta) < sizeof(*param))
		goto badkey;

	param = RTA_DATA(rta);
	enckeylen = be32_to_cpu(param->enckeylen);

	key += RTA_ALIGN(rta->rta_len);
	keylen -= RTA_ALIGN(rta->rta_len);

	if (keylen < enckeylen)
		goto badkey;

	authkeylen = keylen - enckeylen;

	crypto_hash_clear_flags(auth, CRYPTO_TFM_REQ_MASK);
	crypto_hash_set_flags(auth, crypto_aead_get_flags(authenc) &
				    CRYPTO_TFM_REQ_MASK);
	err = crypto_hash_setkey(auth, key, authkeylen);