/*
 *  Public Key abstraction layer: wrapper functions
 *
 *  Copyright (C) 2006-2015, ARM Limited, All Rights Reserved
 *  SPDX-License-Identifier: GPL-2.0
 *
 *  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.
 *
 *  This program is distributed in the hope that it will be useful,
 *  but WITHOUT ANY WARRANTY; without even the implied warranty of
 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *  GNU General Public License for more details.
 *
 *  You should have received a copy of the GNU General Public License along
 *  with this program; if not, write to the Free Software Foundation, Inc.,
 *  51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
 *
 *  This file is part of mbed TLS (https://tls.mbed.org)
 */

#if !defined(MBEDTLS_CONFIG_FILE)
#include "mbedtls/config.h"
#else
#include MBEDTLS_CONFIG_FILE
#endif

#if defined(MBEDTLS_PK_C)
#include "mbedtls/pk_internal.h"

/* Even if RSA not activated, for the sake of RSA-alt */
#include "mbedtls/rsa.h"

#include <string.h>

#if defined(MBEDTLS_ECP_C)
#include "mbedtls/ecp.h"
#endif

#if defined(MBEDTLS_ECDSA_C)
#include "mbedtls/ecdsa.h"
#endif

#if defined(MBEDTLS_PK_RSA_ALT_SUPPORT)
#include "mbedtls/platform_util.h"
#endif

#if defined(MBEDTLS_PLATFORM_C)
#include "mbedtls/platform.h"
#else
#include <stdlib.h>
#define mbedtls_calloc    calloc
#define mbedtls_free       free
#endif

#include <limits.h>
#include <stdint.h>

#if defined(MBEDTLS_RSA_C)
static int rsa_can_do(mbedtls_pk_type_t type) {
    return (type == MBEDTLS_PK_RSA ||
            type == MBEDTLS_PK_RSASSA_PSS);
}

static size_t rsa_get_bitlen(const void *ctx) {
    const mbedtls_rsa_context *rsa = (const mbedtls_rsa_context *) ctx;
    return (8 * mbedtls_rsa_get_len(rsa));
}

static int rsa_verify_wrap(void *ctx, mbedtls_md_type_t md_alg,
                           const unsigned char *hash, size_t hash_len,
                           const unsigned char *sig, size_t sig_len) {
    int ret;
    mbedtls_rsa_context *rsa = (mbedtls_rsa_context *) ctx;
    size_t rsa_len = mbedtls_rsa_get_len(rsa);

#if SIZE_MAX > UINT_MAX
    if (md_alg == MBEDTLS_MD_NONE && UINT_MAX < hash_len)
        return (MBEDTLS_ERR_PK_BAD_INPUT_DATA);
#endif /* SIZE_MAX > UINT_MAX */

    if (sig_len < rsa_len)
        return (MBEDTLS_ERR_RSA_VERIFY_FAILED);

    if ((ret = mbedtls_rsa_pkcs1_verify(rsa, NULL, NULL,
                                        MBEDTLS_RSA_PUBLIC, md_alg,
                                        (unsigned int) hash_len, hash, sig)) != 0)
        return (ret);

    /* The buffer contains a valid signature followed by extra data.
     * We have a special error code for that so that so that callers can
     * use mbedtls_pk_verify() to check "Does the buffer start with a
     * valid signature?" and not just "Does the buffer contain a valid
     * signature?". */
    if (sig_len > rsa_len)
        return (MBEDTLS_ERR_PK_SIG_LEN_MISMATCH);

    return (0);
}

static int rsa_sign_wrap(void *ctx, mbedtls_md_type_t md_alg,
                         const unsigned char *hash, size_t hash_len,
                         unsigned char *sig, size_t *sig_len,
                         int (*f_rng)(void *, unsigned char *, size_t), void *p_rng) {
    mbedtls_rsa_context *rsa = (mbedtls_rsa_context *) ctx;

#if SIZE_MAX > UINT_MAX
    if (md_alg == MBEDTLS_MD_NONE && UINT_MAX < hash_len)
        return (MBEDTLS_ERR_PK_BAD_INPUT_DATA);
#endif /* SIZE_MAX > UINT_MAX */

    *sig_len = mbedtls_rsa_get_len(rsa);

    return (mbedtls_rsa_pkcs1_sign(rsa, f_rng, p_rng, MBEDTLS_RSA_PRIVATE,
                                   md_alg, (unsigned int) hash_len, hash, sig));
}

static int rsa_decrypt_wrap(void *ctx,
                            const unsigned char *input, size_t ilen,
                            unsigned char *output, size_t *olen, size_t osize,
                            int (*f_rng)(void *, unsigned char *, size_t), void *p_rng) {
    mbedtls_rsa_context *rsa = (mbedtls_rsa_context *) ctx;

    if (ilen != mbedtls_rsa_get_len(rsa))
        return (MBEDTLS_ERR_RSA_BAD_INPUT_DATA);

    return (mbedtls_rsa_pkcs1_decrypt(rsa, f_rng, p_rng,
                                      MBEDTLS_RSA_PRIVATE, olen, input, output, osize));
}

static int rsa_encrypt_wrap(void *ctx,
                            const unsigned char *input, size_t ilen,
                            unsigned char *output, size_t *olen, size_t osize,
                            int (*f_rng)(void *, unsigned char *, size_t), void *p_rng) {
    mbedtls_rsa_context *rsa = (mbedtls_rsa_context *) ctx;
    *olen = mbedtls_rsa_get_len(rsa);

    if (*olen > osize)
        return (MBEDTLS_ERR_RSA_OUTPUT_TOO_LARGE);

    return (mbedtls_rsa_pkcs1_encrypt(rsa, f_rng, p_rng, MBEDTLS_RSA_PUBLIC,
                                      ilen, input, output));
}

static int rsa_check_pair_wrap(const void *pub, const void *prv) {
    return (mbedtls_rsa_check_pub_priv((const mbedtls_rsa_context *) pub,
                                       (const mbedtls_rsa_context *) prv));
}

static void *rsa_alloc_wrap(void) {
    void *ctx = mbedtls_calloc(1, sizeof(mbedtls_rsa_context));

    if (ctx != NULL)
        mbedtls_rsa_init((mbedtls_rsa_context *) ctx, 0, 0);

    return (ctx);
}

static void rsa_free_wrap(void *ctx) {
    mbedtls_rsa_free((mbedtls_rsa_context *) ctx);
    mbedtls_free(ctx);
}

static void rsa_debug(const void *ctx, mbedtls_pk_debug_item *items) {
    items->type = MBEDTLS_PK_DEBUG_MPI;
    items->name = "rsa.N";
    items->value = &(((mbedtls_rsa_context *) ctx)->N);

    items++;

    items->type = MBEDTLS_PK_DEBUG_MPI;
    items->name = "rsa.E";
    items->value = &(((mbedtls_rsa_context *) ctx)->E);
}

const mbedtls_pk_info_t mbedtls_rsa_info = {
    MBEDTLS_PK_RSA,
    "RSA",
    rsa_get_bitlen,
    rsa_can_do,
    rsa_verify_wrap,
    rsa_sign_wrap,
    rsa_decrypt_wrap,
    rsa_encrypt_wrap,
    rsa_check_pair_wrap,
    rsa_alloc_wrap,
    rsa_free_wrap,
    rsa_debug,
};
#endif /* MBEDTLS_RSA_C */

#if defined(MBEDTLS_ECP_C)
/*
 * Generic EC key
 */
static int eckey_can_do(mbedtls_pk_type_t type) {
    return (type == MBEDTLS_PK_ECKEY ||
            type == MBEDTLS_PK_ECKEY_DH ||
            type == MBEDTLS_PK_ECDSA);
}

static size_t eckey_get_bitlen(const void *ctx) {
    return (((mbedtls_ecp_keypair *) ctx)->grp.pbits);
}

#if defined(MBEDTLS_ECDSA_C)
/* Forward declarations */
static int ecdsa_verify_wrap(void *ctx, mbedtls_md_type_t md_alg,
                             const unsigned char *hash, size_t hash_len,
                             const unsigned char *sig, size_t sig_len);

static int ecdsa_sign_wrap(void *ctx, mbedtls_md_type_t md_alg,
                           const unsigned char *hash, size_t hash_len,
                           unsigned char *sig, size_t *sig_len,
                           int (*f_rng)(void *, unsigned char *, size_t), void *p_rng);

static int eckey_verify_wrap(void *ctx, mbedtls_md_type_t md_alg,
                             const unsigned char *hash, size_t hash_len,
                             const unsigned char *sig, size_t sig_len) {
    int ret;
    mbedtls_ecdsa_context ecdsa;

    mbedtls_ecdsa_init(&ecdsa);

    if ((ret = mbedtls_ecdsa_from_keypair(&ecdsa, ctx)) == 0)
        ret = ecdsa_verify_wrap(&ecdsa, md_alg, hash, hash_len, sig, sig_len);

    mbedtls_ecdsa_free(&ecdsa);

    return (ret);
}

static int eckey_sign_wrap(void *ctx, mbedtls_md_type_t md_alg,
                           const unsigned char *hash, size_t hash_len,
                           unsigned char *sig, size_t *sig_len,
                           int (*f_rng)(void *, unsigned char *, size_t), void *p_rng) {
    int ret;
    mbedtls_ecdsa_context ecdsa;

    mbedtls_ecdsa_init(&ecdsa);

    if ((ret = mbedtls_ecdsa_from_keypair(&ecdsa, ctx)) == 0)
        ret = ecdsa_sign_wrap(&ecdsa, md_alg, hash, hash_len, sig, sig_len,
                              f_rng, p_rng);

    mbedtls_ecdsa_free(&ecdsa);

    return (ret);
}

#endif /* MBEDTLS_ECDSA_C */

static int eckey_check_pair(const void *pub, const void *prv) {
    return (mbedtls_ecp_check_pub_priv((const mbedtls_ecp_keypair *) pub,
                                       (const mbedtls_ecp_keypair *) prv));
}

static void *eckey_alloc_wrap(void) {
    void *ctx = mbedtls_calloc(1, sizeof(mbedtls_ecp_keypair));

    if (ctx != NULL)
        mbedtls_ecp_keypair_init(ctx);

    return (ctx);
}

static void eckey_free_wrap(void *ctx) {
    mbedtls_ecp_keypair_free((mbedtls_ecp_keypair *) ctx);
    mbedtls_free(ctx);
}

static void eckey_debug(const void *ctx, mbedtls_pk_debug_item *items) {
    items->type = MBEDTLS_PK_DEBUG_ECP;
    items->name = "eckey.Q";
    items->value = &(((mbedtls_ecp_keypair *) ctx)->Q);
}

const mbedtls_pk_info_t mbedtls_eckey_info = {
    MBEDTLS_PK_ECKEY,
    "EC",
    eckey_get_bitlen,
    eckey_can_do,
#if defined(MBEDTLS_ECDSA_C)
    eckey_verify_wrap,
    eckey_sign_wrap,
#else
    NULL,
    NULL,
#endif
    NULL,
    NULL,
    eckey_check_pair,
    eckey_alloc_wrap,
    eckey_free_wrap,
    eckey_debug,
};

/*
 * EC key restricted to ECDH
 */
static int eckeydh_can_do(mbedtls_pk_type_t type) {
    return (type == MBEDTLS_PK_ECKEY ||
            type == MBEDTLS_PK_ECKEY_DH);
}

const mbedtls_pk_info_t mbedtls_eckeydh_info = {
    MBEDTLS_PK_ECKEY_DH,
    "EC_DH",
    eckey_get_bitlen,         /* Same underlying key structure */
    eckeydh_can_do,
    NULL,
    NULL,
    NULL,
    NULL,
    eckey_check_pair,
    eckey_alloc_wrap,       /* Same underlying key structure */
    eckey_free_wrap,        /* Same underlying key structure */
    eckey_debug,            /* Same underlying key structure */
};
#endif /* MBEDTLS_ECP_C */

#if defined(MBEDTLS_ECDSA_C)
static int ecdsa_can_do(mbedtls_pk_type_t type) {
    return (type == MBEDTLS_PK_ECDSA);
}

static int ecdsa_verify_wrap(void *ctx, mbedtls_md_type_t md_alg,
                             const unsigned char *hash, size_t hash_len,
                             const unsigned char *sig, size_t sig_len) {
    int ret;
    ((void) md_alg);

    ret = mbedtls_ecdsa_read_signature((mbedtls_ecdsa_context *) ctx,
                                       hash, hash_len, sig, sig_len);

    if (ret == MBEDTLS_ERR_ECP_SIG_LEN_MISMATCH)
        return (MBEDTLS_ERR_PK_SIG_LEN_MISMATCH);

    return (ret);
}

static int ecdsa_sign_wrap(void *ctx, mbedtls_md_type_t md_alg,
                           const unsigned char *hash, size_t hash_len,
                           unsigned char *sig, size_t *sig_len,
                           int (*f_rng)(void *, unsigned char *, size_t), void *p_rng) {
    return (mbedtls_ecdsa_write_signature((mbedtls_ecdsa_context *) ctx,
                                          md_alg, hash, hash_len, sig, sig_len, f_rng, p_rng));
}

static void *ecdsa_alloc_wrap(void) {
    void *ctx = mbedtls_calloc(1, sizeof(mbedtls_ecdsa_context));

    if (ctx != NULL)
        mbedtls_ecdsa_init((mbedtls_ecdsa_context *) ctx);

    return (ctx);
}

static void ecdsa_free_wrap(void *ctx) {
    mbedtls_ecdsa_free((mbedtls_ecdsa_context *) ctx);
    mbedtls_free(ctx);
}

const mbedtls_pk_info_t mbedtls_ecdsa_info = {
    MBEDTLS_PK_ECDSA,
    "ECDSA",
    eckey_get_bitlen,     /* Compatible key structures */
    ecdsa_can_do,
    ecdsa_verify_wrap,
    ecdsa_sign_wrap,
    NULL,
    NULL,
    eckey_check_pair,   /* Compatible key structures */
    ecdsa_alloc_wrap,
    ecdsa_free_wrap,
    eckey_debug,        /* Compatible key structures */
};
#endif /* MBEDTLS_ECDSA_C */

#if defined(MBEDTLS_PK_RSA_ALT_SUPPORT)
/*
 * Support for alternative RSA-private implementations
 */

static int rsa_alt_can_do(mbedtls_pk_type_t type) {
    return (type == MBEDTLS_PK_RSA);
}

static size_t rsa_alt_get_bitlen(const void *ctx) {
    const mbedtls_rsa_alt_context *rsa_alt = (const mbedtls_rsa_alt_context *) ctx;

    return (8 * rsa_alt->key_len_func(rsa_alt->key));
}

static int rsa_alt_sign_wrap(void *ctx, mbedtls_md_type_t md_alg,
                             const unsigned char *hash, size_t hash_len,
                             unsigned char *sig, size_t *sig_len,
                             int (*f_rng)(void *, unsigned char *, size_t), void *p_rng) {
    mbedtls_rsa_alt_context *rsa_alt = (mbedtls_rsa_alt_context *) ctx;

#if SIZE_MAX > UINT_MAX
    if (UINT_MAX < hash_len)
        return (MBEDTLS_ERR_PK_BAD_INPUT_DATA);
#endif /* SIZE_MAX > UINT_MAX */

    *sig_len = rsa_alt->key_len_func(rsa_alt->key);

    return (rsa_alt->sign_func(rsa_alt->key, f_rng, p_rng, MBEDTLS_RSA_PRIVATE,
                               md_alg, (unsigned int) hash_len, hash, sig));
}

static int rsa_alt_decrypt_wrap(void *ctx,
                                const unsigned char *input, size_t ilen,
                                unsigned char *output, size_t *olen, size_t osize,
                                int (*f_rng)(void *, unsigned char *, size_t), void *p_rng) {
    mbedtls_rsa_alt_context *rsa_alt = (mbedtls_rsa_alt_context *) ctx;

    ((void) f_rng);
    ((void) p_rng);

    if (ilen != rsa_alt->key_len_func(rsa_alt->key))
        return (MBEDTLS_ERR_RSA_BAD_INPUT_DATA);

    return (rsa_alt->decrypt_func(rsa_alt->key,
                                  MBEDTLS_RSA_PRIVATE, olen, input, output, osize));
}

#if defined(MBEDTLS_RSA_C)
static int rsa_alt_check_pair(const void *pub, const void *prv) {
    unsigned char sig[MBEDTLS_MPI_MAX_SIZE];
    unsigned char hash[32];
    size_t sig_len = 0;
    int ret;

    if (rsa_alt_get_bitlen(prv) != rsa_get_bitlen(pub))
        return (MBEDTLS_ERR_RSA_KEY_CHECK_FAILED);

    memset(hash, 0x2a, sizeof(hash));

    if ((ret = rsa_alt_sign_wrap((void *) prv, MBEDTLS_MD_NONE,
                                 hash, sizeof(hash),
                                 sig, &sig_len, NULL, NULL)) != 0) {
        return (ret);
    }

    if (rsa_verify_wrap((void *) pub, MBEDTLS_MD_NONE,
                        hash, sizeof(hash), sig, sig_len) != 0) {
        return (MBEDTLS_ERR_RSA_KEY_CHECK_FAILED);
    }

    return (0);
}
#endif /* MBEDTLS_RSA_C */

static void *rsa_alt_alloc_wrap(void) {
    void *ctx = mbedtls_calloc(1, sizeof(mbedtls_rsa_alt_context));

    if (ctx != NULL)
        memset(ctx, 0, sizeof(mbedtls_rsa_alt_context));

    return (ctx);
}

static void rsa_alt_free_wrap(void *ctx) {
    mbedtls_platform_zeroize(ctx, sizeof(mbedtls_rsa_alt_context));
    mbedtls_free(ctx);
}

const mbedtls_pk_info_t mbedtls_rsa_alt_info = {
    MBEDTLS_PK_RSA_ALT,
    "RSA-alt",
    rsa_alt_get_bitlen,
    rsa_alt_can_do,
    NULL,
    rsa_alt_sign_wrap,
    rsa_alt_decrypt_wrap,
    NULL,
#if defined(MBEDTLS_RSA_C)
    rsa_alt_check_pair,
#else
    NULL,
#endif
    rsa_alt_alloc_wrap,
    rsa_alt_free_wrap,
    NULL,
};

#endif /* MBEDTLS_PK_RSA_ALT_SUPPORT */

#endif /* MBEDTLS_PK_C */