SSLCTXsetcertverifycallback(3) OpenSSLSSLCTXsetcertverifycallback(3)

NAME
       SSLCTXsetcertverifycallback - set peer certificate verification
       procedure

SYNOPSIS
        #include 

        void SSLCTXsetcertverifycallback(SSLCTX *ctx, int (*callback)(X509STORECTX *,void *), void *arg);

DESCRIPTION
       SSLCTXsetcertverifycallback() sets the verification callback
       function for ctx. SSL objects that are created from ctx inherit the
       setting valid at the time when SSLnew(3) is called.

NNOOTTEESS
       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
       SSLCTXsetcertverifycallback(), 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(X509STORECTX *x509storectx, 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 SSLVERIFYPEER 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
       eerrrroorr member of x509storectx so that the calling application will be
       informed about the detailed result of the verification procedure!

       Within x509storectx, callback has access to the verifycallback
       function set using SSLCTXsetverify(3).

WWAARRNNIINNGGSS
       Do not mix the verification callback described in this function with
       the vveerriiffyyccaallllbbaacckk function called during the verification process.
       The latter is set using the SSLCTXsetverify(3) family of functions.

       Providing a complete verification procedure including certificate
       purpose settings etc is a complex task. The built-in procedure is quite
       powerful and in most cases it should be sufficient to modify its
       behaviour using the vveerriiffyyccaallllbbaacckk function.

BUGS
RETURN VALUES
       SSLCTXsetcertverifycallback() does not provide diagnostic
       information.

SEE ALSO
       ssl(3), SSLCTXsetverify(3), SSLgetverifyresult(3),
       SSLCTXloadverifylocations(3)

HISTORY       Previous to OpenSSL 0.9.7, the arg argument to
       SSSSLLCCTTXXsseettcceerrttvveerriiffyyccaallllbbaacckk was ignored, and callback was called
       simply as
        int (*callback)(X509STORECTX *) To compile software written for
       previous versions of OpenSSL, a dummy argument will have to be added to
       callback.



0.9.7l                            2002-02-28SSLCTXsetcertverifycallback(3)