library/pkcs12.c

/*
 *  PKCS#12 Personal Information Exchange Syntax
 *
 *  Copyright The Mbed TLS Contributors
 *  SPDX-License-Identifier: Apache-2.0
 *
 *  Licensed under the Apache License, Version 2.0 (the "License"); you may
 *  not use this file except in compliance with the License.
 *  You may obtain a copy of the License at
 *
 *  http://www.apache.org/licenses/LICENSE-2.0
 *
 *  Unless required by applicable law or agreed to in writing, software
 *  distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
 *  WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 *  See the License for the specific language governing permissions and
 *  limitations under the License.
 */
/*
 *  The PKCS #12 Personal Information Exchange Syntax Standard v1.1
 *
 *  http://www.rsa.com/rsalabs/pkcs/files/h11301-wp-pkcs-12v1-1-personal-information-exchange-syntax.pdf
 *  ftp://ftp.rsasecurity.com/pub/pkcs/pkcs-12/pkcs-12v1-1.asn
 */

#include "common.h"

#if defined(MBEDTLS_PKCS12_C)

#    include "mbedtls/pkcs12.h"
#    include "mbedtls/asn1.h"
#    include "mbedtls/cipher.h"
#    include "mbedtls/platform_util.h"
#    include "mbedtls/error.h"

#    include <string.h>

#    if defined(MBEDTLS_DES_C)
#        include "mbedtls/des.h"
#    endif

#    if defined(MBEDTLS_ASN1_PARSE_C)

static int pkcs12_parse_pbe_params(mbedtls_asn1_buf *params,
                                   mbedtls_asn1_buf *salt,
                                   int *iterations)
{
    int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
    unsigned char **p = &params->p;
    const unsigned char *end = params->p + params->len;

    /*
     *  pkcs-12PbeParams ::= SEQUENCE {
     *    salt          OCTET STRING,
     *    iterations    INTEGER
     *  }
     *
     */
    if (params->tag != (MBEDTLS_ASN1_CONSTRUCTED | MBEDTLS_ASN1_SEQUENCE))
        return (MBEDTLS_ERROR_ADD(MBEDTLS_ERR_PKCS12_PBE_INVALID_FORMAT,
                                  MBEDTLS_ERR_ASN1_UNEXPECTED_TAG));

    if ((ret = mbedtls_asn1_get_tag(p, end, &salt->len,
                                    MBEDTLS_ASN1_OCTET_STRING)) != 0)
        return MBEDTLS_ERROR_ADD(MBEDTLS_ERR_PKCS12_PBE_INVALID_FORMAT, ret);

    salt->p = *p;
    *p += salt->len;

    if ((ret = mbedtls_asn1_get_int(p, end, iterations)) != 0)
        return MBEDTLS_ERROR_ADD(MBEDTLS_ERR_PKCS12_PBE_INVALID_FORMAT, ret);

    if (*p != end)
        return (MBEDTLS_ERROR_ADD(MBEDTLS_ERR_PKCS12_PBE_INVALID_FORMAT,
                                  MBEDTLS_ERR_ASN1_LENGTH_MISMATCH));

    return 0;
}

#        define PKCS12_MAX_PWDLEN 128

static int pkcs12_pbe_derive_key_iv(mbedtls_asn1_buf *pbe_params,
                                    mbedtls_md_type_t md_type,
                                    const unsigned char *pwd,
                                    size_t pwdlen,
                                    unsigned char *key,
                                    size_t keylen,
                                    unsigned char *iv,
                                    size_t ivlen)
{
    int ret, iterations = 0;
    mbedtls_asn1_buf salt;
    size_t i;
    unsigned char unipwd[PKCS12_MAX_PWDLEN * 2 + 2];

    if (pwdlen > PKCS12_MAX_PWDLEN)
        return MBEDTLS_ERR_PKCS12_BAD_INPUT_DATA;

    memset(&salt, 0, sizeof(mbedtls_asn1_buf));
    memset(&unipwd, 0, sizeof(unipwd));

    if ((ret = pkcs12_parse_pbe_params(pbe_params, &salt, &iterations)) != 0)
        return ret;

    for (i = 0; i < pwdlen; i++)
        unipwd[i * 2 + 1] = pwd[i];

    if ((ret = mbedtls_pkcs12_derivation(
             key, keylen, unipwd, pwdlen * 2 + 2, salt.p, salt.len, md_type,
             MBEDTLS_PKCS12_DERIVE_KEY, iterations)) != 0) {
        return ret;
    }

    if (iv == NULL || ivlen == 0)
        return 0;

    if ((ret = mbedtls_pkcs12_derivation(
             iv, ivlen, unipwd, pwdlen * 2 + 2, salt.p, salt.len, md_type,
             MBEDTLS_PKCS12_DERIVE_IV, iterations)) != 0) {
        return ret;
    }
    return 0;
}

#        undef PKCS12_MAX_PWDLEN

int mbedtls_pkcs12_pbe(mbedtls_asn1_buf *pbe_params,
                       int mode,
                       mbedtls_cipher_type_t cipher_type,
                       mbedtls_md_type_t md_type,
                       const unsigned char *pwd,
                       size_t pwdlen,
                       const unsigned char *data,
                       size_t len,
                       unsigned char *output)
{
    int ret, keylen = 0;
    unsigned char key[32];
    unsigned char iv[16];
    const mbedtls_cipher_info_t *cipher_info;
    mbedtls_cipher_context_t cipher_ctx;
    size_t olen = 0;

    cipher_info = mbedtls_cipher_info_from_type(cipher_type);
    if (cipher_info == NULL)
        return MBEDTLS_ERR_PKCS12_FEATURE_UNAVAILABLE;

    keylen = cipher_info->key_bitlen / 8;

    if ((ret = pkcs12_pbe_derive_key_iv(pbe_params, md_type, pwd, pwdlen, key,
                                        keylen, iv, cipher_info->iv_size)) !=
        0) {
        return ret;
    }

    mbedtls_cipher_init(&cipher_ctx);

    if ((ret = mbedtls_cipher_setup(&cipher_ctx, cipher_info)) != 0)
        goto exit;

    if ((ret = mbedtls_cipher_setkey(&cipher_ctx, key, 8 * keylen,
                                     (mbedtls_operation_t)mode)) != 0)
        goto exit;

    if ((ret = mbedtls_cipher_set_iv(&cipher_ctx, iv, cipher_info->iv_size)) !=
        0)
        goto exit;

    if ((ret = mbedtls_cipher_reset(&cipher_ctx)) != 0)
        goto exit;

    if ((ret = mbedtls_cipher_update(&cipher_ctx, data, len, output, &olen)) !=
        0) {
        goto exit;
    }

    if ((ret = mbedtls_cipher_finish(&cipher_ctx, output + olen, &olen)) != 0)
        ret = MBEDTLS_ERR_PKCS12_PASSWORD_MISMATCH;

exit:
    mbedtls_platform_zeroize(key, sizeof(key));
    mbedtls_platform_zeroize(iv, sizeof(iv));
    mbedtls_cipher_free(&cipher_ctx);

    return ret;
}

#    endif /* MBEDTLS_ASN1_PARSE_C */

static void pkcs12_fill_buffer(unsigned char *data,
                               size_t data_len,
                               const unsigned char *filler,
                               size_t fill_len)
{
    unsigned char *p = data;
    size_t use_len;

    while (data_len > 0) {
        use_len = (data_len > fill_len) ? fill_len : data_len;
        memcpy(p, filler, use_len);
        p += use_len;
        data_len -= use_len;
    }
}

int mbedtls_pkcs12_derivation(unsigned char *data,
                              size_t datalen,
                              const unsigned char *pwd,
                              size_t pwdlen,
                              const unsigned char *salt,
                              size_t saltlen,
                              mbedtls_md_type_t md_type,
                              int id,
                              int iterations)
{
    int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
    unsigned int j;

    unsigned char diversifier[128];
    unsigned char salt_block[128], pwd_block[128], hash_block[128];
    unsigned char hash_output[MBEDTLS_MD_MAX_SIZE];
    unsigned char *p;
    unsigned char c;

    size_t hlen, use_len, v, i;

    const mbedtls_md_info_t *md_info;
    mbedtls_md_context_t md_ctx;

    // This version only allows max of 64 bytes of password or salt
    if (datalen > 128 || pwdlen > 64 || saltlen > 64)
        return MBEDTLS_ERR_PKCS12_BAD_INPUT_DATA;

    md_info = mbedtls_md_info_from_type(md_type);
    if (md_info == NULL)
        return MBEDTLS_ERR_PKCS12_FEATURE_UNAVAILABLE;

    mbedtls_md_init(&md_ctx);

    if ((ret = mbedtls_md_setup(&md_ctx, md_info, 0)) != 0)
        return ret;
    hlen = mbedtls_md_get_size(md_info);

    if (hlen <= 32)
        v = 64;
    else
        v = 128;

    memset(diversifier, (unsigned char)id, v);

    pkcs12_fill_buffer(salt_block, v, salt, saltlen);
    pkcs12_fill_buffer(pwd_block, v, pwd, pwdlen);

    p = data;
    while (datalen > 0) {
        // Calculate hash( diversifier || salt_block || pwd_block )
        if ((ret = mbedtls_md_starts(&md_ctx)) != 0)
            goto exit;

        if ((ret = mbedtls_md_update(&md_ctx, diversifier, v)) != 0)
            goto exit;

        if ((ret = mbedtls_md_update(&md_ctx, salt_block, v)) != 0)
            goto exit;

        if ((ret = mbedtls_md_update(&md_ctx, pwd_block, v)) != 0)
            goto exit;

        if ((ret = mbedtls_md_finish(&md_ctx, hash_output)) != 0)
            goto exit;

        // Perform remaining ( iterations - 1 ) recursive hash calculations
        for (i = 1; i < (size_t)iterations; i++) {
            if ((ret = mbedtls_md(md_info, hash_output, hlen, hash_output)) !=
                0)
                goto exit;
        }

        use_len = (datalen > hlen) ? hlen : datalen;
        memcpy(p, hash_output, use_len);
        datalen -= use_len;
        p += use_len;

        if (datalen == 0)
            break;

        // Concatenating copies of hash_output into hash_block (B)
        pkcs12_fill_buffer(hash_block, v, hash_output, hlen);

        // B += 1
        for (i = v; i > 0; i--)
            if (++hash_block[i - 1] != 0)
                break;

        // salt_block += B
        c = 0;
        for (i = v; i > 0; i--) {
            j = salt_block[i - 1] + hash_block[i - 1] + c;
            c = (unsigned char)(j >> 8);
            salt_block[i - 1] = j & 0xFF;
        }

        // pwd_block  += B
        c = 0;
        for (i = v; i > 0; i--) {
            j = pwd_block[i - 1] + hash_block[i - 1] + c;
            c = (unsigned char)(j >> 8);
            pwd_block[i - 1] = j & 0xFF;
        }
    }

    ret = 0;

exit:
    mbedtls_platform_zeroize(salt_block, sizeof(salt_block));
    mbedtls_platform_zeroize(pwd_block, sizeof(pwd_block));
    mbedtls_platform_zeroize(hash_block, sizeof(hash_block));
    mbedtls_platform_zeroize(hash_output, sizeof(hash_output));

    mbedtls_md_free(&md_ctx);

    return ret;
}

#endif /* MBEDTLS_PKCS12_C */