- NAME
- SYNOPSIS
- DESCRIPTION
- NOTES
- WARNINGS
- BUGS
- SEE ALSO
- COPYRIGHT

# NAME

SSL_CTX_set_cert_verify_callback - set peer certificate verification procedure

# SYNOPSIS

     #include <openssl/ssl.h>

     void SSL_CTX_set_cert_verify_callback(SSL_CTX *ctx, int (*callback)(X509_STORE_CTX *, void *), void *arg);

# DESCRIPTION

SSL_CTX_set_cert_verify_callback() sets the verification callback function for ctx. SSL objects that are created from ctx inherit the setting valid at the time when NOTES

Whenever a certificate is verified during a SSL/TLS handshake, a verification function is called. If the application does not explicitly specify a verification callback function, the built-in verification function is used. If a verification callback callback is specified via SSL_CTX_set_cert_verify_callback(), the supplied callback function is called instead. By setting callback to NULL, the default behaviour is restored.

When the verification must be performed, callback will be called with the arguments callback(X509_STORE_CTX *x509_store_ctx, void *arg). The argument arg is specified by the application when setting callback.

callback should return 1 to indicate verification success and 0 to indicate verification failure. If SSL_VERIFY_PEER is set and callback returns 0, the handshake will fail. As the verification procedure may allow to continue the connection in case of failure (by always returning 1) the verification result must be set in any case using the error member of x509_store_ctx so that the calling application will be informed about the detailed result of the verification procedure!

Within x509_store_ctx, callback has access to the verify_callback function set using WARNINGS

Do not mix the verification callback described in this function with the verify_callback function called during the verification process. The latter is set using the BUGS

SSL_CTX_set_cert_verify_callback() does not provide diagnostic information.

# SEE ALSO

SSL_CTX_set_verify(3), SSL_CTX_load_verify_locations(3)

# COPYRIGHT

Copyright 2001-2016 The OpenSSL Project Authors. All Rights Reserved.

Licensed under the OpenSSL license (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 https://www.openssl.org/source/license.html.