// SPDX-License-Identifier: GPL-2.0-only
/*
 * Copyright 2003-2004, Instant802 Networks, Inc.
 * Copyright 2005-2006, Devicescape Software, Inc.
 * Copyright 2014-2015, Qualcomm Atheros, Inc.
 *
 * Rewrite: Copyright (C) 2013 Linaro Ltd <ard.biesheuvel@linaro.org>
 */

#include <linux/kernel.h>
#include <linux/types.h>
#include <linux/err.h>
#include <linux/scatterlist.h>
#include <crypto/aead.h>

#include "aead_api.h"

int aead_encrypt(struct crypto_aead *tfm, u8 *b_0, u8 *aad, size_t aad_len,
                 u8 *data, size_t data_len, u8 *mic)
{
        size_t mic_len = crypto_aead_authsize(tfm);
        struct scatterlist sg[3];
        struct aead_request *aead_req;
        int reqsize = sizeof(*aead_req) + crypto_aead_reqsize(tfm);
        u8 *__aad;
        int ret;

        aead_req = kzalloc(reqsize + aad_len, GFP_ATOMIC);
        if (!aead_req)
                return -ENOMEM;

        __aad = (u8 *)aead_req + reqsize;
        memcpy(__aad, aad, aad_len);

        sg_init_table(sg, 3);
        sg_set_buf(&sg[0], __aad, aad_len);
        sg_set_buf(&sg[1], data, data_len);
        sg_set_buf(&sg[2], mic, mic_len);

        aead_request_set_tfm(aead_req, tfm);
        aead_request_set_crypt(aead_req, sg, sg, data_len, b_0);
        aead_request_set_ad(aead_req, sg[0].length);

        ret = crypto_aead_encrypt(aead_req);
        kfree_sensitive(aead_req);

        return ret;
}

int aead_decrypt(struct crypto_aead *tfm, u8 *b_0, u8 *aad, size_t aad_len,
                 u8 *data, size_t data_len, u8 *mic)
{
        size_t mic_len = crypto_aead_authsize(tfm);
        struct scatterlist sg[3];
        struct aead_request *aead_req;
        int reqsize = sizeof(*aead_req) + crypto_aead_reqsize(tfm);
        u8 *__aad;
        int err;

        if (data_len == 0)
                return -EINVAL;

        aead_req = kzalloc(reqsize + aad_len, GFP_ATOMIC);
        if (!aead_req)
                return -ENOMEM;

        __aad = (u8 *)aead_req + reqsize;
        memcpy(__aad, aad, aad_len);

        sg_init_table(sg, 3);
        sg_set_buf(&sg[0], __aad, aad_len);
        sg_set_buf(&sg[1], data, data_len);
        sg_set_buf(&sg[2], mic, mic_len);

        aead_request_set_tfm(aead_req, tfm);
        aead_request_set_crypt(aead_req, sg, sg, data_len + mic_len, b_0);
        aead_request_set_ad(aead_req, sg[0].length);

        err = crypto_aead_decrypt(aead_req);
        kfree_sensitive(aead_req);

        return err;
}

struct crypto_aead *
aead_key_setup_encrypt(const char *alg, const u8 key[],
                       size_t key_len, size_t mic_len)
{
        struct crypto_aead *tfm;
        int err;

        tfm = crypto_alloc_aead(alg, 0, CRYPTO_ALG_ASYNC);
        if (IS_ERR(tfm))
                return tfm;

        err = crypto_aead_setkey(tfm, key, key_len);
        if (err)
                goto free_aead;
        err = crypto_aead_setauthsize(tfm, mic_len);
        if (err)
                goto free_aead;

        return tfm;

free_aead:
        crypto_free_aead(tfm);
        return ERR_PTR(err);
}

void aead_key_free(struct crypto_aead *tfm)
{
        crypto_free_aead(tfm);
}