| =pod |
| |
| =head1 NAME |
| |
| X509_verify_cert - discover and verify X509 certificate chain |
| |
| =head1 SYNOPSIS |
| |
| #include <openssl/x509.h> |
| |
| int X509_verify_cert(X509_STORE_CTX *ctx); |
| |
| =head1 DESCRIPTION |
| |
| The X509_verify_cert() function attempts to discover and validate a |
| certificate chain based on parameters in B<ctx>. |
| The verification context, of type B<X509_STORE_CTX>, can be constructed |
| using L<X509_STORE_CTX_new(3)> and L<X509_STORE_CTX_init(3)>. |
| It usually includes a set of certificates serving as trust anchors, |
| a set of non-trusted certificates that may be needed for chain construction, |
| flags such as X509_V_FLAG_X509_STRICT, and various other optional components |
| such as a callback function that allows customizing the verification outcome. |
| A complete description of the certificate verification process is contained in |
| the L<openssl-verify(1)> manual page. |
| |
| Applications rarely call this function directly but it is used by |
| OpenSSL internally for certificate validation, in both the S/MIME and |
| SSL/TLS code. |
| |
| A negative return value from X509_verify_cert() can occur if it is invoked |
| incorrectly, such as with no certificate set in B<ctx>, or when it is called |
| twice in succession without reinitialising B<ctx> for the second call. |
| A negative return value can also happen due to internal resource problems or if |
| a retry operation is requested during internal lookups (which never happens |
| with standard lookup methods). |
| Applications must check for <= 0 return value on error. |
| |
| =head1 RETURN VALUES |
| |
| If a complete chain can be built and validated this function returns 1, |
| otherwise it return zero, in exceptional circumstances it can also |
| return a negative code. |
| |
| If the function fails additional error information can be obtained by |
| examining B<ctx> using, for example L<X509_STORE_CTX_get_error(3)>. |
| |
| =head1 BUGS |
| |
| This function uses the header F<< <x509.h> >> |
| as opposed to most chain verification |
| functions which use F<< <x509_vfy.h> >>. |
| |
| =head1 SEE ALSO |
| |
| L<X509_STORE_CTX_new(3)>, L<X509_STORE_CTX_init(3)>, |
| L<X509_STORE_CTX_get_error(3)> |
| |
| =head1 COPYRIGHT |
| |
| Copyright 2009-2020 The OpenSSL Project Authors. All Rights Reserved. |
| |
| Licensed under the Apache License 2.0 (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 |
| L<https://www.openssl.org/source/license.html>. |
| |
| =cut |
