library/pkcs11.c

/**
 * \file pkcs11.c
 *
 * \brief Wrapper for PKCS#11 library libpkcs11-helper
 *
 * \author Adriaan de Jong <dejong@fox-it.com>
 *
 *  Copyright The Mbed TLS Contributors
 *  SPDX-License-Identifier: Apache-2.0 OR GPL-2.0-or-later
 */

#include "mbedtls/pkcs11.h"

#if defined(MBEDTLS_PKCS11_C)

#include "mbedtls/md.h"
#include "mbedtls/oid.h"
#include "mbedtls/x509_crt.h"

#include "mbedtls/platform.h"

#include <string.h>

void mbedtls_pkcs11_init(mbedtls_pkcs11_context *ctx)
{
    memset(ctx, 0, sizeof(mbedtls_pkcs11_context));
}

int mbedtls_pkcs11_x509_cert_bind(mbedtls_x509_crt *cert, pkcs11h_certificate_t pkcs11_cert)
{
    int ret = 1;
    unsigned char *cert_blob = NULL;
    size_t cert_blob_size = 0;

    if (cert == NULL) {
        ret = 2;
        goto cleanup;
    }

    if (pkcs11h_certificate_getCertificateBlob(pkcs11_cert, NULL,
                                               &cert_blob_size) != CKR_OK) {
        ret = 3;
        goto cleanup;
    }

    cert_blob = mbedtls_calloc(1, cert_blob_size);
    if (NULL == cert_blob) {
        ret = 4;
        goto cleanup;
    }

    if (pkcs11h_certificate_getCertificateBlob(pkcs11_cert, cert_blob,
                                               &cert_blob_size) != CKR_OK) {
        ret = 5;
        goto cleanup;
    }

    if (0 != mbedtls_x509_crt_parse(cert, cert_blob, cert_blob_size)) {
        ret = 6;
        goto cleanup;
    }

    ret = 0;

cleanup:
    if (NULL != cert_blob) {
        mbedtls_free(cert_blob);
    }

    return ret;
}


int mbedtls_pkcs11_priv_key_bind(mbedtls_pkcs11_context *priv_key,
                                 pkcs11h_certificate_t pkcs11_cert)
{
    int ret = 1;
    mbedtls_x509_crt cert;

    mbedtls_x509_crt_init(&cert);

    if (priv_key == NULL) {
        goto cleanup;
    }

    if (0 != mbedtls_pkcs11_x509_cert_bind(&cert, pkcs11_cert)) {
        goto cleanup;
    }

    priv_key->len = mbedtls_pk_get_len(&cert.pk);
    priv_key->pkcs11h_cert = pkcs11_cert;

    ret = 0;

cleanup:
    mbedtls_x509_crt_free(&cert);

    return ret;
}

void mbedtls_pkcs11_priv_key_free(mbedtls_pkcs11_context *priv_key)
{
    if (NULL != priv_key) {
        pkcs11h_certificate_freeCertificate(priv_key->pkcs11h_cert);
    }
}

int mbedtls_pkcs11_decrypt(mbedtls_pkcs11_context *ctx,
                           int mode, size_t *olen,
                           const unsigned char *input,
                           unsigned char *output,
                           size_t output_max_len)
{
    size_t input_len, output_len;

    if (NULL == ctx) {
        return MBEDTLS_ERR_RSA_BAD_INPUT_DATA;
    }

    if (MBEDTLS_RSA_PRIVATE != mode) {
        return MBEDTLS_ERR_RSA_BAD_INPUT_DATA;
    }

    output_len = input_len = ctx->len;

    if (input_len < 16 || input_len > output_max_len) {
        return MBEDTLS_ERR_RSA_BAD_INPUT_DATA;
    }

    /* Determine size of output buffer */
    if (pkcs11h_certificate_decryptAny(ctx->pkcs11h_cert, CKM_RSA_PKCS, input,
                                       input_len, NULL, &output_len) != CKR_OK) {
        return MBEDTLS_ERR_RSA_BAD_INPUT_DATA;
    }

    if (output_len > output_max_len) {
        return MBEDTLS_ERR_RSA_OUTPUT_TOO_LARGE;
    }

    if (pkcs11h_certificate_decryptAny(ctx->pkcs11h_cert, CKM_RSA_PKCS, input,
                                       input_len, output, &output_len) != CKR_OK) {
        return MBEDTLS_ERR_RSA_BAD_INPUT_DATA;
    }
    *olen = output_len;
    return 0;
}

int mbedtls_pkcs11_sign(mbedtls_pkcs11_context *ctx,
                        int mode,
                        mbedtls_md_type_t md_alg,
                        unsigned int hashlen,
                        const unsigned char *hash,
                        unsigned char *sig)
{
    size_t sig_len = 0, asn_len = 0, oid_size = 0;
    unsigned char *p = sig;
    const char *oid;

    if (NULL == ctx) {
        return MBEDTLS_ERR_RSA_BAD_INPUT_DATA;
    }

    if (MBEDTLS_RSA_PRIVATE != mode) {
        return MBEDTLS_ERR_RSA_BAD_INPUT_DATA;
    }

    if (md_alg != MBEDTLS_MD_NONE) {
        const mbedtls_md_info_t *md_info = mbedtls_md_info_from_type(md_alg);
        if (md_info == NULL) {
            return MBEDTLS_ERR_RSA_BAD_INPUT_DATA;
        }

        if (mbedtls_oid_get_oid_by_md(md_alg, &oid, &oid_size) != 0) {
            return MBEDTLS_ERR_RSA_BAD_INPUT_DATA;
        }

        hashlen = mbedtls_md_get_size(md_info);
        asn_len = 10 + oid_size;
    }

    sig_len = ctx->len;
    if (hashlen > sig_len || asn_len > sig_len ||
        hashlen + asn_len > sig_len) {
        return MBEDTLS_ERR_RSA_BAD_INPUT_DATA;
    }

    if (md_alg != MBEDTLS_MD_NONE) {
        /*
         * DigestInfo ::= SEQUENCE {
         *   digestAlgorithm DigestAlgorithmIdentifier,
         *   digest Digest }
         *
         * DigestAlgorithmIdentifier ::= AlgorithmIdentifier
         *
         * Digest ::= OCTET STRING
         */
        *p++ = MBEDTLS_ASN1_SEQUENCE | MBEDTLS_ASN1_CONSTRUCTED;
        *p++ = (unsigned char) (0x08 + oid_size + hashlen);
        *p++ = MBEDTLS_ASN1_SEQUENCE | MBEDTLS_ASN1_CONSTRUCTED;
        *p++ = (unsigned char) (0x04 + oid_size);
        *p++ = MBEDTLS_ASN1_OID;
        *p++ = oid_size & 0xFF;
        memcpy(p, oid, oid_size);
        p += oid_size;
        *p++ = MBEDTLS_ASN1_NULL;
        *p++ = 0x00;
        *p++ = MBEDTLS_ASN1_OCTET_STRING;
        *p++ = hashlen;
    }

    memcpy(p, hash, hashlen);

    if (pkcs11h_certificate_signAny(ctx->pkcs11h_cert, CKM_RSA_PKCS, sig,
                                    asn_len + hashlen, sig, &sig_len) != CKR_OK) {
        return MBEDTLS_ERR_RSA_BAD_INPUT_DATA;
    }

    return 0;
}

#endif /* defined(MBEDTLS_PKCS11_C) */