doc/man3/OSSL_DECODER_from_bio.pod

   1 =pod
   2
   3 =head1 NAME
   4
   5 OSSL_DECODER_from_data,
   6 OSSL_DECODER_from_bio,
   7 OSSL_DECODER_from_fp
   8 - Routines to perform a decoding
   9
  10 =head1 SYNOPSIS
  11
  12  #include <openssl/decoder.h>
  13
  14  int OSSL_DECODER_from_bio(OSSL_DECODER_CTX *ctx, BIO *in);
  15  int OSSL_DECODER_from_fp(OSSL_DECODER_CTX *ctx, FILE *fp);
  16  int OSSL_DECODER_from_data(OSSL_DECODER_CTX *ctx, const unsigned char **pdata,
  17                             size_t *pdata_len);
  18
  19 Feature availability macros:
  20
  21 =over 4
  22
  23 =item OSSL_DECODER_from_fp() is only available when B<OPENSSL_NO_STDIO>
  24 is undefined.
  25
  26 =back
  27
  28 =head1 DESCRIPTION
  29
  30 OSSL_DECODER_from_data() runs the decoding process for the context I<ctx>,
  31 with input coming from I<*pdata>, I<*pdata_len> bytes long.  Both I<*pdata>
  32 and I<*pdata_len> must be non-NULL.  When OSSL_DECODER_from_data() returns,
  33 I<*pdata> is updated to point at the location after what has been decoded,
  34 and I<*pdata_len> to have the number of remaining bytes.
  35
  36 OSSL_DECODER_from_bio() runs the decoding process for the context I<ctx>,
  37 with the input coming from the B<BIO> I<in>.  Should it make a difference,
  38 it's recommended to have the BIO set in binary mode rather than text mode.
  39
  40 OSSL_DECODER_from_fp() does the same thing as OSSL_DECODER_from_bio(),
  41 except that the input is coming from the B<FILE> I<fp>.
  42
  43 =head1 RETURN VALUES
  44
  45 OSSL_DECODER_from_bio() and OSSL_DECODER_from_fp() return 1 on success, or 0
  46 on failure.
  47
  48 =head1 EXAMPLES
  49
  50 To decode an RSA key encoded with PEM from a bio:
  51
  52  OSSL_DECODER_CTX *dctx;
  53  EVP_PKEY *pkey = NULL;
  54  const char *format = "PEM";   /* NULL for any format */
  55  const char *structure = NULL; /* any structure */
  56  const char *keytype = "RSA";  /* NULL for any key */
  57  const unsigned char *pass = "my password";
  58
  59  dctx = OSSL_DECODER_CTX_new_for_pkey(&pkey, format, structure,
  60                                       keytype,
  61                                       OSSL_KEYMGMT_SELECT_KEYPAIR,
  62                                       NULL, NULL);
  63  if (dctx == NULL) {
  64      /* error: no suitable potential decoders found */
  65  }
  66  if (pass != NULL)
  67      OSSL_DECODER_CTX_set_passphrase(dctx, pass, strlen(pass));
  68  if (OSSL_DECODER_from_bio(dctx, bio)) {
  69      /* pkey is created with the decoded data from the bio */
  70  } else {
  71      /* decoding failure */
  72  }
  73  OSSL_DECODER_CTX_free(dctx);
  74
  75 To decode an EC key encoded with DER from a buffer:
  76
  77  OSSL_DECODER_CTX *dctx;
  78  EVP_PKEY *pkey = NULL;
  79  const char *format = "DER";   /* NULL for any format */
  80  const char *structure = NULL; /* any structure */
  81  const char *keytype = "EC";   /* NULL for any key */
  82  const unsigned char *pass = NULL
  83  const unsigned char *data = buffer;
  84  size_t datalen = sizeof(buffer);
  85
  86  dctx = OSSL_DECODER_CTX_new_for_pkey(&pkey, format, structure,
  87                                       keytype,
  88                                       OSSL_KEYMGMT_SELECT_KEYPAIR
  89                                       | OSSL_KEYMGMT_SELECT_DOMAIN_PARAMETERS,
  90                                       NULL, NULL);
  91  if (dctx == NULL) {
  92      /* error: no suitable potential decoders found */
  93  }
  94  if (pass != NULL)
  95      OSSL_DECODER_CTX_set_passphrase(dctx, pass, strlen(pass));
  96  if (OSSL_DECODER_from_data(dctx, &data, &datalen)) {
  97      /* pkey is created with the decoded data from the buffer */
  98  } else {
  99      /* decoding failure */
 100  }
 101  OSSL_DECODER_CTX_free(dctx);
 102
 103 =head1 SEE ALSO
 104
 105 L<provider(7)>, L<OSSL_DECODER_CTX(3)>
 106
 107 =head1 HISTORY
 108
 109 The functions described here were added in OpenSSL 3.0.
 110
 111 =head1 COPYRIGHT
 112
 113 Copyright 2020-2021 The OpenSSL Project Authors. All Rights Reserved.
 114
 115 Licensed under the Apache License 2.0 (the "License").  You may not use
 116 this file except in compliance with the License.  You can obtain a copy
 117 in the file LICENSE in the source distribution or at
 118 L<https://www.openssl.org/source/license.html>.
 119
 120 =cut