/*

 * Copyright 2007-2016 The OpenSSL Project Authors. All Rights Reserved.

 *

 * Licensed under the OpenSSL license (the "License").  You may not use

 * this file except in compliance with the License.  You can obtain a copy

 * in the file LICENSE in the source distribution or at

 * https://www.openssl.org/source/license.html

 */

/* Simple S/MIME verification example */

#include <openssl/pem.h>

#include <openssl/pkcs7.h>

#include <openssl/err.h>

int main(int argc, char **argv)

{

    BIO *in = NULL, *out = NULL, *tbio = NULL, *cont = NULL;

    X509_STORE *st = NULL;

    X509 *cacert = NULL;

    PKCS7 *p7 = NULL;

    int ret = 1;

    OpenSSL_add_all_algorithms();

    ERR_load_crypto_strings();

    /* Set up trusted CA certificate store */

    st = X509_STORE_new();

    /* Read in signer certificate and private key */

    tbio = BIO_new_file("cacert.pem", "r");

    if (!tbio)

        goto err;

    cacert = PEM_read_bio_X509(tbio, NULL, 0, NULL);

    if (!cacert)

        goto err;

    if (!X509_STORE_add_cert(st, cacert))

        goto err;

    /* Open content being signed */

    in = BIO_new_file("smout.txt", "r");

    if (!in)

        goto err;

    /* Sign content */

    p7 = SMIME_read_PKCS7(in, &cont;;

    if (!p7)

        goto err;

    /* File to output verified content to */

    out = BIO_new_file("smver.txt", "w");

    if (!out)

        goto err;

    if (!PKCS7_verify(p7, NULL, st, cont, out, 0)) {

        fprintf(stderr, "Verification Failure\n");

        goto err;

    }

    fprintf(stderr, "Verification Successful\n");

    ret = 0;

 err:

    if (ret) {

        fprintf(stderr, "Error Verifying Data\n");

        ERR_print_errors_fp(stderr);

    }

    PKCS7_free(p7);

    X509_free(cacert);

    BIO_free(in);

    BIO_free(out);

    BIO_free(tbio);

    return ret;

}