demos/cms/cms_sign.c

   1 /*
   2  * Copyright 2008-2023 The OpenSSL Project Authors. All Rights Reserved.
   3  *
   4  * Licensed under the Apache License 2.0 (the "License").  You may not use
   5  * this file except in compliance with the License.  You can obtain a copy
   6  * in the file LICENSE in the source distribution or at
   7  * https://www.openssl.org/source/license.html
   8  */
   9
  10 /* Simple S/MIME signing example */
  11 #include <openssl/pem.h>
  12 #include <openssl/cms.h>
  13 #include <openssl/err.h>
  14
  15 int main(int argc, char **argv)
  16 {
  17     BIO *in = NULL, *out = NULL, *tbio = NULL;
  18     X509 *scert = NULL;
  19     EVP_PKEY *skey = NULL;
  20     CMS_ContentInfo *cms = NULL;
  21     int ret = EXIT_FAILURE;
  22
  23     /*
  24      * For simple S/MIME signing use CMS_DETACHED. On OpenSSL 1.0.0 only: for
  25      * streaming detached set CMS_DETACHED|CMS_STREAM for streaming
  26      * non-detached set CMS_STREAM
  27      */
  28     int flags = CMS_DETACHED | CMS_STREAM;
  29
  30     OpenSSL_add_all_algorithms();
  31     ERR_load_crypto_strings();
  32
  33     /* Read in signer certificate and private key */
  34     tbio = BIO_new_file("signer.pem", "r");
  35
  36     if (!tbio)
  37         goto err;
  38
  39     scert = PEM_read_bio_X509(tbio, NULL, 0, NULL);
  40
  41     BIO_reset(tbio);
  42
  43     skey = PEM_read_bio_PrivateKey(tbio, NULL, 0, NULL);
  44
  45     if (!scert || !skey)
  46         goto err;
  47
  48     /* Open content being signed */
  49
  50     in = BIO_new_file("sign.txt", "r");
  51
  52     if (!in)
  53         goto err;
  54
  55     /* Sign content */
  56     cms = CMS_sign(scert, skey, NULL, in, flags);
  57
  58     if (!cms)
  59         goto err;
  60
  61     out = BIO_new_file("smout.txt", "w");
  62     if (!out)
  63         goto err;
  64
  65     if (!(flags & CMS_STREAM))
  66         BIO_reset(in);
  67
  68     /* Write out S/MIME message */
  69     if (!SMIME_write_CMS(out, cms, in, flags))
  70         goto err;
  71
  72     ret = EXIT_SUCCESS;
  73  err:
  74     if (ret != EXIT_SUCCESS) {
  75         fprintf(stderr, "Error Signing Data\n");
  76         ERR_print_errors_fp(stderr);
  77     }
  78
  79     CMS_ContentInfo_free(cms);
  80     X509_free(scert);
  81     EVP_PKEY_free(skey);
  82     BIO_free(in);
  83     BIO_free(out);
  84     BIO_free(tbio);
  85     return ret;
  86 }