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			213 lines
		
	
	
		
			7.4 KiB
		
	
	
	
		
			Plaintext
		
	
	
	
			
		
		
	
	
			213 lines
		
	
	
		
			7.4 KiB
		
	
	
	
		
			Plaintext
		
	
	
	
| =pod
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| 
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| =head1 NAME
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| 
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| X509_STORE_CTX_get_cleanup,
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| X509_STORE_CTX_get_lookup_crls,
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| X509_STORE_CTX_get_lookup_certs,
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| X509_STORE_CTX_get_check_policy,
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| X509_STORE_CTX_get_cert_crl,
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| X509_STORE_CTX_get_check_crl,
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| X509_STORE_CTX_get_get_crl,
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| X509_STORE_CTX_get_check_revocation,
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| X509_STORE_CTX_get_check_issued,
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| X509_STORE_CTX_get_get_issuer,
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| X509_STORE_CTX_get_verify_cb,
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| X509_STORE_CTX_set_verify_cb,
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| X509_STORE_CTX_verify_cb
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| - get and set verification callback
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| 
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| =head1 SYNOPSIS
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| 
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|  #include <openssl/x509_vfy.h>
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| 
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|  typedef int (*X509_STORE_CTX_verify_cb)(int, X509_STORE_CTX *);
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| 
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|  X509_STORE_CTX_verify_cb X509_STORE_CTX_get_verify_cb(X509_STORE_CTX *ctx);
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| 
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|  void X509_STORE_CTX_set_verify_cb(X509_STORE_CTX *ctx,
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|                                    X509_STORE_CTX_verify_cb verify_cb);
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| 
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|  X509_STORE_CTX_get_issuer_fn X509_STORE_CTX_get_get_issuer(X509_STORE_CTX *ctx);
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|  X509_STORE_CTX_check_issued_fn X509_STORE_CTX_get_check_issued(X509_STORE_CTX *ctx);
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|  X509_STORE_CTX_check_revocation_fn X509_STORE_CTX_get_check_revocation(X509_STORE_CTX *ctx);
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|  X509_STORE_CTX_get_crl_fn X509_STORE_CTX_get_get_crl(X509_STORE_CTX *ctx);
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|  X509_STORE_CTX_check_crl_fn X509_STORE_CTX_get_check_crl(X509_STORE_CTX *ctx);
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|  X509_STORE_CTX_cert_crl_fn X509_STORE_CTX_get_cert_crl(X509_STORE_CTX *ctx);
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|  X509_STORE_CTX_check_policy_fn X509_STORE_CTX_get_check_policy(X509_STORE_CTX *ctx);
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|  X509_STORE_CTX_lookup_certs_fn X509_STORE_CTX_get_lookup_certs(X509_STORE_CTX *ctx);
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|  X509_STORE_CTX_lookup_crls_fn X509_STORE_CTX_get_lookup_crls(X509_STORE_CTX *ctx);
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|  X509_STORE_CTX_cleanup_fn X509_STORE_CTX_get_cleanup(X509_STORE_CTX *ctx);
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| 
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| =head1 DESCRIPTION
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| 
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| X509_STORE_CTX_set_verify_cb() sets the verification callback of B<ctx> to
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| B<verify_cb> overwriting any existing callback.
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| 
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| The verification callback can be used to customise the operation of certificate
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| verification, either by overriding error conditions or logging errors for
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| debugging purposes.
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| 
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| However a verification callback is B<not> essential and the default operation
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| is often sufficient.
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| 
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| The B<ok> parameter to the callback indicates the value the callback should
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| return to retain the default behaviour. If it is zero then an error condition
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| is indicated. If it is 1 then no error occurred. If the flag
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| B<X509_V_FLAG_NOTIFY_POLICY> is set then B<ok> is set to 2 to indicate the
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| policy checking is complete.
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| 
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| The B<ctx> parameter to the callback is the B<X509_STORE_CTX> structure that
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| is performing the verification operation. A callback can examine this
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| structure and receive additional information about the error, for example
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| by calling X509_STORE_CTX_get_current_cert(). Additional application data can
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| be passed to the callback via the B<ex_data> mechanism.
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| 
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| X509_STORE_CTX_get_verify_cb() returns the value of the current callback
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| for the specific B<ctx>.
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| 
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| X509_STORE_CTX_get_get_issuer(),
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| X509_STORE_CTX_get_check_issued(), X509_STORE_CTX_get_check_revocation(),
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| X509_STORE_CTX_get_get_crl(), X509_STORE_CTX_get_check_crl(),
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| X509_STORE_CTX_get_cert_crl(), X509_STORE_CTX_get_check_policy(),
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| X509_STORE_CTX_get_lookup_certs(), X509_STORE_CTX_get_lookup_crls()
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| and X509_STORE_CTX_get_cleanup() return the function pointers cached
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| from the corresponding B<X509_STORE>, please see
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| L<X509_STORE_set_verify(3)> for more information.
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| 
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| 
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| =head1 WARNING
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| 
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| In general a verification callback should B<NOT> unconditionally return 1 in
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| all circumstances because this will allow verification to succeed no matter
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| what the error. This effectively removes all security from the application
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| because B<any> certificate (including untrusted generated ones) will be
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| accepted.
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| 
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| =head1 NOTES
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| 
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| The verification callback can be set and inherited from the parent structure
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| performing the operation. In some cases (such as S/MIME verification) the
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| B<X509_STORE_CTX> structure is created and destroyed internally and the
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| only way to set a custom verification callback is by inheriting it from the
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| associated B<X509_STORE>.
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| 
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| =head1 RETURN VALUES
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| 
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| X509_STORE_CTX_set_verify_cb() does not return a value.
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| 
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| =head1 EXAMPLES
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| 
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| Default callback operation:
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| 
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|  int verify_callback(int ok, X509_STORE_CTX *ctx) {
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|      return ok;
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|  }
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| 
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| Simple example, suppose a certificate in the chain is expired and we wish
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| to continue after this error:
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| 
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|  int verify_callback(int ok, X509_STORE_CTX *ctx) {
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|      /* Tolerate certificate expiration */
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|      if (X509_STORE_CTX_get_error(ctx) == X509_V_ERR_CERT_HAS_EXPIRED)
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|          return 1;
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|      /* Otherwise don't override */
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|      return ok;
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|  }
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| 
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| More complex example, we don't wish to continue after B<any> certificate has
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| expired just one specific case:
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| 
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|  int verify_callback(int ok, X509_STORE_CTX *ctx)
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|  {
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|      int err = X509_STORE_CTX_get_error(ctx);
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|      X509 *err_cert = X509_STORE_CTX_get_current_cert(ctx);
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| 
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|      if (err == X509_V_ERR_CERT_HAS_EXPIRED) {
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|          if (check_is_acceptable_expired_cert(err_cert)
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|              return 1;
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|      }
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|      return ok;
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|  }
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| 
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| Full featured logging callback. In this case the B<bio_err> is assumed to be
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| a global logging B<BIO>, an alternative would to store a BIO in B<ctx> using
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| B<ex_data>.
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| 
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|  int verify_callback(int ok, X509_STORE_CTX *ctx)
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|  {
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|      X509 *err_cert;
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|      int err, depth;
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| 
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|      err_cert = X509_STORE_CTX_get_current_cert(ctx);
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|      err = X509_STORE_CTX_get_error(ctx);
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|      depth = X509_STORE_CTX_get_error_depth(ctx);
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| 
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|      BIO_printf(bio_err, "depth=%d ", depth);
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|      if (err_cert) {
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|          X509_NAME_print_ex(bio_err, X509_get_subject_name(err_cert),
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|                             0, XN_FLAG_ONELINE);
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|          BIO_puts(bio_err, "\n");
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|      }
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|      else
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|          BIO_puts(bio_err, "<no cert>\n");
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|      if (!ok)
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|          BIO_printf(bio_err, "verify error:num=%d:%s\n", err,
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|                     X509_verify_cert_error_string(err));
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|      switch (err) {
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|      case X509_V_ERR_UNABLE_TO_GET_ISSUER_CERT:
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|          BIO_puts(bio_err, "issuer= ");
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|          X509_NAME_print_ex(bio_err, X509_get_issuer_name(err_cert),
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|                             0, XN_FLAG_ONELINE);
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|          BIO_puts(bio_err, "\n");
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|          break;
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|      case X509_V_ERR_CERT_NOT_YET_VALID:
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|      case X509_V_ERR_ERROR_IN_CERT_NOT_BEFORE_FIELD:
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|          BIO_printf(bio_err, "notBefore=");
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|          ASN1_TIME_print(bio_err, X509_get_notBefore(err_cert));
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|          BIO_printf(bio_err, "\n");
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|          break;
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|      case X509_V_ERR_CERT_HAS_EXPIRED:
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|      case X509_V_ERR_ERROR_IN_CERT_NOT_AFTER_FIELD:
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|          BIO_printf(bio_err, "notAfter=");
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|          ASN1_TIME_print(bio_err, X509_get_notAfter(err_cert));
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|          BIO_printf(bio_err, "\n");
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|          break;
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|      case X509_V_ERR_NO_EXPLICIT_POLICY:
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|          policies_print(bio_err, ctx);
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|          break;
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|      }
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|      if (err == X509_V_OK && ok == 2)
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|          /* print out policies */
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| 
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|      BIO_printf(bio_err, "verify return:%d\n", ok);
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|      return(ok);
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|  }
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| 
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| =head1 SEE ALSO
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| 
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| L<X509_STORE_CTX_get_error(3)>
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| L<X509_STORE_set_verify_cb_func(3)>
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| L<X509_STORE_CTX_get_ex_new_index(3)>
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| 
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| =head1 HISTORY
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| 
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| The
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| X509_STORE_CTX_get_get_issuer(),
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| X509_STORE_CTX_get_check_issued(), X509_STORE_CTX_get_check_revocation(),
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| X509_STORE_CTX_get_get_crl(), X509_STORE_CTX_get_check_crl(),
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| X509_STORE_CTX_get_cert_crl(), X509_STORE_CTX_get_check_policy(),
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| X509_STORE_CTX_get_lookup_certs(), X509_STORE_CTX_get_lookup_crls()
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| and X509_STORE_CTX_get_cleanup() functions were added in OpenSSL 1.1.0.
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| 
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| =head1 COPYRIGHT
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| 
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| Copyright 2009-2016 The OpenSSL Project Authors. All Rights Reserved.
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| 
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| Licensed under the Apache License 2.0 (the "License").  You may not use
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| this file except in compliance with the License.  You can obtain a copy
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| in the file LICENSE in the source distribution or at
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| L<https://www.openssl.org/source/license.html>.
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| 
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| =cut
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