1.\" $OpenBSD: X509_verify_cert.3,v 1.8 2019/06/06 01:06:59 schwarze Exp $ 2.\" OpenSSL 99d63d46 Oct 26 13:56:48 2016 -0400 3.\" 4.\" This file was written by Dr. Stephen Henson <steve@openssl.org>. 5.\" Copyright (c) 2009, 2015 The OpenSSL Project. All rights reserved. 6.\" 7.\" Redistribution and use in source and binary forms, with or without 8.\" modification, are permitted provided that the following conditions 9.\" are met: 10.\" 11.\" 1. Redistributions of source code must retain the above copyright 12.\" notice, this list of conditions and the following disclaimer. 13.\" 14.\" 2. Redistributions in binary form must reproduce the above copyright 15.\" notice, this list of conditions and the following disclaimer in 16.\" the documentation and/or other materials provided with the 17.\" distribution. 18.\" 19.\" 3. All advertising materials mentioning features or use of this 20.\" software must display the following acknowledgment: 21.\" "This product includes software developed by the OpenSSL Project 22.\" for use in the OpenSSL Toolkit. (http://www.openssl.org/)" 23.\" 24.\" 4. The names "OpenSSL Toolkit" and "OpenSSL Project" must not be used to 25.\" endorse or promote products derived from this software without 26.\" prior written permission. For written permission, please contact 27.\" openssl-core@openssl.org. 28.\" 29.\" 5. Products derived from this software may not be called "OpenSSL" 30.\" nor may "OpenSSL" appear in their names without prior written 31.\" permission of the OpenSSL Project. 32.\" 33.\" 6. Redistributions of any form whatsoever must retain the following 34.\" acknowledgment: 35.\" "This product includes software developed by the OpenSSL Project 36.\" for use in the OpenSSL Toolkit (http://www.openssl.org/)" 37.\" 38.\" THIS SOFTWARE IS PROVIDED BY THE OpenSSL PROJECT ``AS IS'' AND ANY 39.\" EXPRESSED OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 40.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR 41.\" PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE OpenSSL PROJECT OR 42.\" ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, 43.\" SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 44.\" NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; 45.\" LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 46.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, 47.\" STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) 48.\" ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED 49.\" OF THE POSSIBILITY OF SUCH DAMAGE. 50.\" 51.Dd $Mdocdate: June 6 2019 $ 52.Dt X509_VERIFY_CERT 3 53.Os 54.Sh NAME 55.Nm X509_verify_cert 56.Nd discover and verify X509 certificate chain 57.Sh SYNOPSIS 58.In openssl/x509.h 59.Ft int 60.Fo X509_verify_cert 61.Fa "X509_STORE_CTX *ctx" 62.Fc 63.Sh DESCRIPTION 64The 65.Fn X509_verify_cert 66function attempts to discover and validate a certificate chain based on 67parameters in 68.Fa ctx . 69.Pp 70Applications rarely call this function directly, but it is used by 71OpenSSL internally for certificate validation, in both the S/MIME and 72SSL/TLS code. 73.Sh RETURN VALUES 74If a complete chain can be built and validated this function returns 1, 75otherwise it returns a value <= 0 indicating failure. 76.Pp 77Additional error information can be obtained by examining 78.Fa ctx , 79using 80.Xr X509_STORE_CTX_get_error 3 . 81.Sh SEE ALSO 82.Xr openssl 1 , 83.Xr X509_STORE_CTX_get_error 3 , 84.Xr X509_STORE_CTX_new 3 85.Sh HISTORY 86.Fn X509_verify_cert 87first appeared in SSLeay 0.8.0 and has been available since 88.Ox 2.4 . 89.Sh BUGS 90This function uses the header 91.In openssl/x509.h 92as opposed to most chain verification functions which use 93.In openssl/x509_vfy.h . 94