Added gnutls_certificate_get_issuer() to allow getting the issuer a certificate from...

diff --git a/.gitignore b/.gitignore
index be6c73bae2abfb0138003fdf921b93d1a44c061d..d0fc83e5b87097d4ca02090a1793612e1e32c3dc 100644 (file)
--- a/.gitignore
+++ b/.gitignore
@@ -452,3 +452,4 @@ lib/ext/libgnutls_ext.la
 lib/auth/libgnutls_auth.la
 tests/cipher-test
 tests/suite/x509paths/X509tests
+tests/x509cert

diff --git a/NEWS b/NEWS
index 00ced7cb6c8ba2b97c23591367cbcc06e29a287e..eea62cac8ea8dc67d5c41130a103e59a73687419 100644 (file)
--- a/NEWS
+++ b/NEWS
@@ -3,6 +3,16 @@ Copyright (C) 2000, 2001, 2002, 2003, 2004, 2005,
               2006, 2007, 2008, 2009, 2010 Free Software Foundation, Inc.
 See the end for copying conditions.
 
+* Version 2.99.2 (unreleased)
+
+** libgnutls: Added gnutls_certificate_get_issuer() and
+gnutls_x509_trust_list_get_issuer() to compensate for the
+missing gnutls_certificate_get_x509_cas().
+
+** API and ABI modifications:
+gnutls_certificate_get_issuer: ADDED
+gnutls_x509_trust_list_get_issuer: ADDED
+
 * Version 2.99.1 (released 2011-04-23)
 
 ** libgnutls: LZO support was removed.

diff --git a/lib/gnutls_cert.c b/lib/gnutls_cert.c
index 91ad7caccfd1bef3c9a1c2c715baba797e7a4ff5..2b8101c24bdb082cfe815f616ead2ddcf5995781 100644 (file)
--- a/lib/gnutls_cert.c
+++ b/lib/gnutls_cert.c
@@ -1,6 +1,6 @@
 /*
  * Copyright (C) 2001, 2002, 2003, 2004, 2005, 2006, 2007, 2008, 2009,
- * 2010 Free Software Foundation, Inc.
+ * 2010,2011 Free Software Foundation, Inc.
  *
  * Author: Nikos Mavrogiannopoulos
  *
@@ -101,6 +101,25 @@ gnutls_certificate_free_cas (gnutls_certificate_credentials_t sc)
   return;
 }
 
+/**
+ * gnutls_certificate_get_issuer:
+ * @sc: is a #gnutls_certificate_credentials_t structure.
+ * @cert: is the certificate to find issuer for
+ * @issuer: Will hold the issuer if any. Should be treated as constant.
+ * @flags: Use zero.
+ *
+ * This function will return the issuer of a given certificate.
+ *
+ * Returns: On success, %GNUTLS_E_SUCCESS is returned, otherwise a
+ *   negative error value.
+ **/
+int
+gnutls_certificate_get_issuer (gnutls_certificate_credentials_t sc,
+  gnutls_x509_crt_t cert, gnutls_x509_crt_t* issuer, unsigned int flags)
+{
+  return gnutls_trust_list_get_issuer(sc->tlist, cert, issuer, flags);
+}
+
 /**
  * gnutls_certificate_free_ca_names:
  * @sc: is a #gnutls_certificate_credentials_t structure.

diff --git a/lib/includes/gnutls/gnutls.h.in b/lib/includes/gnutls/gnutls.h.in
index 0cdbffd27a30d402bfff8949587e0ce8682ddfcc..46ea4a86f05048ebb07a4e5c21d226fa639b4c13 100644 (file)
--- a/lib/includes/gnutls/gnutls.h.in
+++ b/lib/includes/gnutls/gnutls.h.in
@@ -944,6 +944,24 @@ extern "C"
                               gnutls_credentials_type_t type, void *cred);
 #define gnutls_cred_set        gnutls_credentials_set
 
+/* x.509 types */
+
+  struct gnutls_x509_privkey_int;
+  typedef struct gnutls_x509_privkey_int *gnutls_x509_privkey_t;
+
+  struct gnutls_x509_crl_int;
+  typedef struct gnutls_x509_crl_int *gnutls_x509_crl_t;
+
+  struct gnutls_x509_crt_int;
+  typedef struct gnutls_x509_crt_int *gnutls_x509_crt_t;
+
+  struct gnutls_x509_crq_int;
+  typedef struct gnutls_x509_crq_int *gnutls_x509_crq_t;
+
+  struct gnutls_openpgp_keyring_int;
+  typedef struct gnutls_openpgp_keyring_int *gnutls_openpgp_keyring_t;
+
+
 /* Credential structures - used in gnutls_credentials_set(); */
 
   struct gnutls_certificate_credentials_st;
@@ -988,6 +1006,10 @@ extern "C"
     gnutls_certificate_allocate_credentials (gnutls_certificate_credentials_t
                                              * res);
 
+  int
+    gnutls_certificate_get_issuer (gnutls_certificate_credentials_t sc,
+    gnutls_x509_crt_t cert, gnutls_x509_crt_t* issuer, unsigned int flags);
+
   void gnutls_certificate_free_keys (gnutls_certificate_credentials_t sc);
   void gnutls_certificate_free_cas (gnutls_certificate_credentials_t sc);
   void gnutls_certificate_free_ca_names (gnutls_certificate_credentials_t sc);
@@ -1043,20 +1065,6 @@ extern "C"
 
 /* New functions to allow setting already parsed X.509 stuff.
  */
-  struct gnutls_x509_privkey_int;
-  typedef struct gnutls_x509_privkey_int *gnutls_x509_privkey_t;
-
-  struct gnutls_x509_crl_int;
-  typedef struct gnutls_x509_crl_int *gnutls_x509_crl_t;
-
-  struct gnutls_x509_crt_int;
-  typedef struct gnutls_x509_crt_int *gnutls_x509_crt_t;
-
-  struct gnutls_x509_crq_int;
-  typedef struct gnutls_x509_crq_int *gnutls_x509_crq_t;
-
-  struct gnutls_openpgp_keyring_int;
-  typedef struct gnutls_openpgp_keyring_int *gnutls_openpgp_keyring_t;
 
   int gnutls_certificate_set_x509_key (gnutls_certificate_credentials_t res,
                                        gnutls_x509_crt_t * cert_list,

diff --git a/lib/includes/gnutls/x509.h b/lib/includes/gnutls/x509.h
index a3afeeb372ae69fe7437141948ca2c77181f1b91..f220844d77e2520bac4fcd527b3330b599b3f62a 100644 (file)
--- a/lib/includes/gnutls/x509.h
+++ b/lib/includes/gnutls/x509.h
@@ -836,6 +836,9 @@ extern "C"
   void
   gnutls_x509_trust_list_deinit (gnutls_x509_trust_list_t list, unsigned int all);
 
+  int gnutls_trust_list_get_issuer(gnutls_x509_trust_list_t list,
+    gnutls_x509_crt_t cert, gnutls_x509_crt_t* issuer, unsigned int flags);
+
   int
   gnutls_x509_trust_list_add_cas (gnutls_x509_trust_list_t list, 
     const gnutls_x509_crt_t * clist, int clist_size, unsigned int flags);

diff --git a/lib/libgnutls.map b/lib/libgnutls.map
index 87d70cc37b10b6bb7afdbd6bfe45663d9cd29379..229792e955bf37a537e862590848d83345e4bd24 100644 (file)
--- a/lib/libgnutls.map
+++ b/lib/libgnutls.map
@@ -709,6 +709,8 @@ GNUTLS_3_0_0 {
        gnutls_pcert_import_openpgp_raw;
        gnutls_pubkey_get_openpgp_key_id;
        gnutls_certificate_set_retrieve_function2;
+       gnutls_x509_trust_list_get_issuer;
+       gnutls_certificate_get_issuer;
 } GNUTLS_2_12;
 
 GNUTLS_PRIVATE {

diff --git a/lib/x509/verify-high.c b/lib/x509/verify-high.c
index 8452009a271d1acbf6f3beee281921d1e5d163fd..f91122988e5bdcdc09849ab4f7f04f1cc7fa114c 100644 (file)
--- a/lib/x509/verify-high.c
+++ b/lib/x509/verify-high.c
@@ -314,6 +314,50 @@ gnutls_datum_t dn;
   return clist_size;
 }
 
+/**
+ * gnutls_x509_trust_list_get_issuer:
+ * @list: The structure of the list
+ * @cert: is the certificate to find issuer for
+ * @issuer: Will hold the issuer if any. Should be treated as constant.
+ * @flags: Use zero.
+ *
+ * This function will attempt to find the issuer of the
+ * given certificate.
+ *
+ * Returns: On success, %GNUTLS_E_SUCCESS is returned, otherwise a
+ *   negative error value.
+ **/
+int gnutls_trust_list_get_issuer(gnutls_x509_trust_list_t list,
+  gnutls_x509_crt_t cert, gnutls_x509_crt_t* issuer, unsigned int flags)
+{
+gnutls_datum_t dn;
+int ret, i;
+uint32_t hash;
+
+  ret = gnutls_x509_crt_get_raw_issuer_dn(cert, &dn);
+  if (ret < 0)
+    {
+      gnutls_assert();
+      return ret;
+    }
+
+  hash = _gnutls_bhash(dn.data, dn.size, INIT_HASH);
+  hash %= list->size;
+
+  _gnutls_free_datum(&dn);
+
+  for (i=0;i<list->node[hash].trusted_crt_size;i++)
+    {
+      ret = gnutls_x509_crt_check_issuer (cert, list->node[hash].trusted_crts[i]);
+      if (ret == 1)
+        {
+          *issuer = list->node[hash].trusted_crts[i];
+          return 0;
+        }
+    }
+
+  return GNUTLS_E_REQUESTED_DATA_NOT_AVAILABLE;
+}
 
 /**
  * gnutls_x509_trust_list_verify_crt:

diff --git a/tests/Makefile.am b/tests/Makefile.am
index 3c58d68f75b7311cab6bfcc786e8c1b5642a418a..48b1e41398e2f0d326d12180d3e7a73ebca7d024 100644 (file)
--- a/tests/Makefile.am
+++ b/tests/Makefile.am
@@ -64,7 +64,8 @@ ctests = simple gc set_pkcs12_cred certder certuniqueid mpi                   \
        crq_key_id x509sign-verify cve-2009-1415 cve-2009-1416          \
        crq_apis init_roundtrip pkcs12_s2k_pem dn2 mini-eagain          \
        nul-in-x509-names x509_altname pkcs12_encode mini-x509          \
-       mini-x509-rehandshake rng-fork mini-eagain-dtls cipher-test #gendh
+       mini-x509-rehandshake rng-fork mini-eagain-dtls cipher-test     \
+       x509cert #gendh
 
 if ENABLE_OPENSSL
 ctests +=  openssl

diff --git a/tests/x509cert.c b/tests/x509cert.c
new file mode 100644 (file)
index 0000000..ddc08d6
--- /dev/null
+++ b/tests/x509cert.c
@@ -0,0 +1,187 @@
+/*
+ * Copyright (C) 2011 Free Software Foundation, Inc.
+ *
+ * Author: Nikos Mavrogiannopoulos
+ *
+ * This file is part of GnuTLS.
+ *
+ * GnuTLS is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * GnuTLS is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with GnuTLS; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA
+ */
+
+/* Parts copied from GnuTLS example programs. */
+
+#ifdef HAVE_CONFIG_H
+#include <config.h>
+#endif
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <sys/types.h>
+#if !defined(_WIN32)
+#include <netinet/in.h>
+#include <sys/socket.h>
+#include <sys/wait.h>
+#include <arpa/inet.h>
+#endif
+#include <unistd.h>
+#include <gnutls/gnutls.h>
+#include <gnutls/x509.h>
+
+#include "utils.h"
+
+/* Test for gnutls_certificate_get_issuer() and implicitly for
+ * gnutls_trust_list_get_issuer().
+ */
+
+static void
+tls_log_func (int level, const char *str)
+{
+  fprintf (stderr, "<%d>| %s", level, str);
+}
+
+static unsigned char ca_pem[] =
+  "-----BEGIN CERTIFICATE-----\n"
+  "MIIB5zCCAVKgAwIBAgIERiYdJzALBgkqhkiG9w0BAQUwGTEXMBUGA1UEAxMOR251\n"
+  "VExTIHRlc3QgQ0EwHhcNMDcwNDE4MTMyOTExWhcNMDgwNDE3MTMyOTExWjAZMRcw\n"
+  "FQYDVQQDEw5HbnVUTFMgdGVzdCBDQTCBnDALBgkqhkiG9w0BAQEDgYwAMIGIAoGA\n"
+  "vuyYeh1vfmslnuggeEKgZAVmQ5ltSdUY7H25WGSygKMUYZ0KT74v8C780qtcNt9T\n"
+  "7EPH/N6RvB4BprdssgcQLsthR3XKA84jbjjxNCcaGs33lvOz8A1nf8p3hD+cKfRi\n"
+  "kfYSW2JazLrtCC4yRCas/SPOUxu78of+3HiTfFm/oXUCAwEAAaNDMEEwDwYDVR0T\n"
+  "AQH/BAUwAwEB/zAPBgNVHQ8BAf8EBQMDBwQAMB0GA1UdDgQWBBTpPBz7rZJu5gak\n"
+  "Viyi4cBTJ8jylTALBgkqhkiG9w0BAQUDgYEAiaIRqGfp1jPpNeVhABK60SU0KIAy\n"
+  "njuu7kHq5peUgYn8Jd9zNzExBOEp1VOipGsf6G66oQAhDFp2o8zkz7ZH71zR4HEW\n"
+  "KoX6n5Emn6DvcEH/9pAhnGxNHJAoS7czTKv/JDZJhkqHxyrE1fuLsg5Qv25DTw7+\n"
+  "PfqUpIhz5Bbm7J4=\n" "-----END CERTIFICATE-----\n";
+const gnutls_datum_t ca = { ca_pem, sizeof (ca_pem) };
+
+static unsigned char cert_pem[] =
+  "-----BEGIN CERTIFICATE-----\n"
+  "MIICHjCCAYmgAwIBAgIERiYdNzALBgkqhkiG9w0BAQUwGTEXMBUGA1UEAxMOR251\n"
+  "VExTIHRlc3QgQ0EwHhcNMDcwNDE4MTMyOTI3WhcNMDgwNDE3MTMyOTI3WjAdMRsw\n"
+  "GQYDVQQDExJHbnVUTFMgdGVzdCBjbGllbnQwgZwwCwYJKoZIhvcNAQEBA4GMADCB\n"
+  "iAKBgLtmQ/Xyxde2jMzF3/WIO7HJS2oOoa0gUEAIgKFPXKPQ+GzP5jz37AR2ExeL\n"
+  "ZIkiW8DdU3w77XwEu4C5KL6Om8aOoKUSy/VXHqLnu7czSZ/ju0quak1o/8kR4jKN\n"
+  "zj2AC41179gAgY8oBAOgIo1hBAf6tjd9IQdJ0glhaZiQo1ipAgMBAAGjdjB0MAwG\n"
+  "A1UdEwEB/wQCMAAwEwYDVR0lBAwwCgYIKwYBBQUHAwIwDwYDVR0PAQH/BAUDAweg\n"
+  "ADAdBgNVHQ4EFgQUTLkKm/odNON+3svSBxX+odrLaJEwHwYDVR0jBBgwFoAU6Twc\n"
+  "+62SbuYGpFYsouHAUyfI8pUwCwYJKoZIhvcNAQEFA4GBALujmBJVZnvaTXr9cFRJ\n"
+  "jpfc/3X7sLUsMvumcDE01ls/cG5mIatmiyEU9qI3jbgUf82z23ON/acwJf875D3/\n"
+  "U7jyOsBJ44SEQITbin2yUeJMIm1tievvdNXBDfW95AM507ShzP12sfiJkJfjjdhy\n"
+  "dc8Siq5JojruiMizAf0pA7in\n" "-----END CERTIFICATE-----\n";
+const gnutls_datum_t cert = { cert_pem, sizeof (cert_pem) };
+
+static unsigned char key_pem[] =
+  "-----BEGIN RSA PRIVATE KEY-----\n"
+  "MIICXAIBAAKBgQC7ZkP18sXXtozMxd/1iDuxyUtqDqGtIFBACIChT1yj0Phsz+Y8\n"
+  "9+wEdhMXi2SJIlvA3VN8O+18BLuAuSi+jpvGjqClEsv1Vx6i57u3M0mf47tKrmpN\n"
+  "aP/JEeIyjc49gAuNde/YAIGPKAQDoCKNYQQH+rY3fSEHSdIJYWmYkKNYqQIDAQAB\n"
+  "AoGADpmARG5CQxS+AesNkGmpauepiCz1JBF/JwnyiX6vEzUh0Ypd39SZztwrDxvF\n"
+  "PJjQaKVljml1zkJpIDVsqvHdyVdse8M+Qn6hw4x2p5rogdvhhIL1mdWo7jWeVJTF\n"
+  "RKB7zLdMPs3ySdtcIQaF9nUAQ2KJEvldkO3m/bRJFEp54k0CQQDYy+RlTmwRD6hy\n"
+  "7UtMjR0H3CSZJeQ8svMCxHLmOluG9H1UKk55ZBYfRTsXniqUkJBZ5wuV1L+pR9EK\n"
+  "ca89a+1VAkEA3UmBelwEv2u9cAU1QjKjmwju1JgXbrjEohK+3B5y0ESEXPAwNQT9\n"
+  "TrDM1m9AyxYTWLxX93dI5QwNFJtmbtjeBQJARSCWXhsoaDRG8QZrCSjBxfzTCqZD\n"
+  "ZXtl807ymCipgJm60LiAt0JLr4LiucAsMZz6+j+quQbSakbFCACB8SLV1QJBAKZQ\n"
+  "YKf+EPNtnmta/rRKKvySsi3GQZZN+Dt3q0r094XgeTsAqrqujVNfPhTMeP4qEVBX\n"
+  "/iVX2cmMTSh3w3z8MaECQEp0XJWDVKOwcTW6Ajp9SowtmiZ3YDYo1LF9igb4iaLv\n"
+  "sWZGfbnU3ryjvkb6YuFjgtzbZDZHWQCo8/cOtOBmPdk=\n"
+  "-----END RSA PRIVATE KEY-----\n";
+const gnutls_datum_t key = { key_pem, sizeof (key_pem) };
+
+static unsigned char server_cert_pem[] =
+  "-----BEGIN CERTIFICATE-----\n"
+  "MIICVjCCAcGgAwIBAgIERiYdMTALBgkqhkiG9w0BAQUwGTEXMBUGA1UEAxMOR251\n"
+  "VExTIHRlc3QgQ0EwHhcNMDcwNDE4MTMyOTIxWhcNMDgwNDE3MTMyOTIxWjA3MRsw\n"
+  "GQYDVQQKExJHbnVUTFMgdGVzdCBzZXJ2ZXIxGDAWBgNVBAMTD3Rlc3QuZ251dGxz\n"
+  "Lm9yZzCBnDALBgkqhkiG9w0BAQEDgYwAMIGIAoGA17pcr6MM8C6pJ1aqU46o63+B\n"
+  "dUxrmL5K6rce+EvDasTaDQC46kwTHzYWk95y78akXrJutsoKiFV1kJbtple8DDt2\n"
+  "DZcevensf9Op7PuFZKBroEjOd35znDET/z3IrqVgbtm2jFqab7a+n2q9p/CgMyf1\n"
+  "tx2S5Zacc1LWn9bIjrECAwEAAaOBkzCBkDAMBgNVHRMBAf8EAjAAMBoGA1UdEQQT\n"
+  "MBGCD3Rlc3QuZ251dGxzLm9yZzATBgNVHSUEDDAKBggrBgEFBQcDATAPBgNVHQ8B\n"
+  "Af8EBQMDB6AAMB0GA1UdDgQWBBTrx0Vu5fglyoyNgw106YbU3VW0dTAfBgNVHSME\n"
+  "GDAWgBTpPBz7rZJu5gakViyi4cBTJ8jylTALBgkqhkiG9w0BAQUDgYEAaFEPTt+7\n"
+  "bzvBuOf7+QmeQcn29kT6Bsyh1RHJXf8KTk5QRfwp6ogbp94JQWcNQ/S7YDFHglD1\n"
+  "AwUNBRXwd3riUsMnsxgeSDxYBfJYbDLeohNBsqaPDJb7XailWbMQKfAbFQ8cnOxg\n"
+  "rOKLUQRWJ0K3HyXRMhbqjdLIaQiCvQLuizo=\n" "-----END CERTIFICATE-----\n";
+
+const gnutls_datum_t server_cert = { server_cert_pem,
+  sizeof (server_cert_pem)
+};
+
+static unsigned char server_key_pem[] =
+  "-----BEGIN RSA PRIVATE KEY-----\n"
+  "MIICXAIBAAKBgQDXulyvowzwLqknVqpTjqjrf4F1TGuYvkrqtx74S8NqxNoNALjq\n"
+  "TBMfNhaT3nLvxqResm62ygqIVXWQlu2mV7wMO3YNlx696ex/06ns+4VkoGugSM53\n"
+  "fnOcMRP/PciupWBu2baMWppvtr6far2n8KAzJ/W3HZLllpxzUtaf1siOsQIDAQAB\n"
+  "AoGAYAFyKkAYC/PYF8e7+X+tsVCHXppp8AoP8TEZuUqOZz/AArVlle/ROrypg5kl\n"
+  "8YunrvUdzH9R/KZ7saNZlAPLjZyFG9beL/am6Ai7q7Ma5HMqjGU8kTEGwD7K+lbG\n"
+  "iomokKMOl+kkbY/2sI5Czmbm+/PqLXOjtVc5RAsdbgvtmvkCQQDdV5QuU8jap8Hs\n"
+  "Eodv/tLJ2z4+SKCV2k/7FXSKWe0vlrq0cl2qZfoTUYRnKRBcWxc9o92DxK44wgPi\n"
+  "oMQS+O7fAkEA+YG+K9e60sj1K4NYbMPAbYILbZxORDecvP8lcphvwkOVUqbmxOGh\n"
+  "XRmTZUuhBrJhJKKf6u7gf3KWlPl6ShKEbwJASC118cF6nurTjuLf7YKARDjNTEws\n"
+  "qZEeQbdWYINAmCMj0RH2P0mvybrsXSOD5UoDAyO7aWuqkHGcCLv6FGG+qwJAOVqq\n"
+  "tXdUucl6GjOKKw5geIvRRrQMhb/m5scb+5iw8A4LEEHPgGiBaF5NtJZLALgWfo5n\n"
+  "hmC8+G8F0F78znQtPwJBANexu+Tg5KfOnzSILJMo3oXiXhf5PqXIDmbN0BKyCKAQ\n"
+  "LfkcEcUbVfmDaHpvzwY9VEaoMOKVLitETXdNSxVpvWM=\n"
+  "-----END RSA PRIVATE KEY-----\n";
+
+const gnutls_datum_t server_key = { server_key_pem,
+  sizeof (server_key_pem)
+};
+
+
+void
+doit (void)
+{
+  gnutls_certificate_credentials_t x509_cred;
+  int ret;
+  gnutls_x509_crt_t crt, issuer;
+  char dn[128];
+  size_t dn_size;
+
+  /* this must be called once in the program
+   */
+  gnutls_global_init ();
+
+  gnutls_global_set_log_function (tls_log_func);
+  if (debug)
+    gnutls_global_set_log_level (6);
+
+  gnutls_certificate_allocate_credentials (&x509_cred);
+  gnutls_certificate_set_x509_trust_mem (x509_cred, &ca, GNUTLS_X509_FMT_PEM);
+
+  gnutls_certificate_set_x509_key_mem (x509_cred, &server_cert, &server_key,
+                                       GNUTLS_X509_FMT_PEM);
+
+  /* test for gnutls_certificate_get_issuer() */
+  gnutls_x509_crt_init(&crt);
+  ret = gnutls_x509_crt_import(crt, &cert, GNUTLS_X509_FMT_PEM);
+  if (ret < 0)
+    fail("gnutls_x509_crt_import");
+  
+  ret = gnutls_certificate_get_issuer(x509_cred, crt, &issuer, 0);
+  if (ret < 0)
+    fail("gnutls_certificate_get_isser");
+
+  dn_size = sizeof(dn);
+  ret = gnutls_x509_crt_get_dn(issuer, dn, &dn_size);
+  if (ret < 0)
+    fail("gnutls_certificate_get_isser");
+  
+  fprintf(stderr, "Issuer's DN: %s\n", dn);
+  
+  success("success");
+}