Skip site navigation (1)Skip section navigation (2)

FreeBSD Manual Pages


home | help

       SSL_check_chain - check certificate chain suitability

	#include <openssl/ssl.h>

	int SSL_check_chain(SSL	*s, X509 *x, EVP_PKEY *pk, STACK_OF(X509) *chain);

       SSL_check_chain() checks	whether	certificate x, private key pk and
       certificate chain chain is suitable for use with	the current session s.

       SSL_check_chain() returns a bitmap of flags indicating the validity of
       the chain.

       CERT_PKEY_VALID:	the chain can be used with the current session.	 If
       this flag is not	set then the certificate will never be used even if
       the application tries to	set it because it is inconsistent with the
       peer preferences.

       CERT_PKEY_SIGN: the EE key can be used for signing.

       CERT_PKEY_EE_SIGNATURE: the signature algorithm of the EE certificate
       is acceptable.

       CERT_PKEY_CA_SIGNATURE: the signature algorithms	of all CA certificates
       are acceptable.

       CERT_PKEY_EE_PARAM: the parameters of the end entity certificate	are
       acceptable (e.g.	it is a	supported curve).

       CERT_PKEY_CA_PARAM: the parameters of all CA certificates are

       CERT_PKEY_EXPLICIT_SIGN:	the end	entity certificate algorithm can be
       used explicitly for signing (i.e. it is mentioned in the	signature
       algorithms extension).

       CERT_PKEY_ISSUER_NAME: the issuer name is acceptable. This is only
       meaningful for client authentication.

       CERT_PKEY_CERT_TYPE: the	certificate type is acceptable.	Only
       meaningful for client authentication.

       CERT_PKEY_SUITEB: chain is suitable for Suite B use.

       SSL_check_chain() must be called	in servers after a client hello
       message or in clients after a certificate request message. It will
       typically be called in the certificate callback.

       An application wishing to support multiple certificate chains may call
       this function on	each chain in turn: starting with the one it considers
       the most	secure.	It could then use the chain of the first set which
       returns suitable	flags.

       As a minimum the	flag CERT_PKEY_VALID must be set for a chain to	be
       usable. An application supporting multiple chains with different	CA
       signature algorithms may	also wish to check CERT_PKEY_CA_SIGNATURE too.
       If no chain is suitable a server	should fall back to the	most secure
       chain which sets	CERT_PKEY_VALID.

       The validity of a chain is determined by	checking if it matches a
       supported signature algorithm, supported	curves and in the case of
       client authentication certificate types and issuer names.

       Since the supported signature algorithms	extension is only used in TLS
       1.2, TLS	1.3 and	DTLS 1.2 the results for earlier versions of TLS and
       DTLS may	not be very useful. Applications may wish to specify a
       different "legacy" chain	for earlier versions of	TLS or DTLS.

       SSL_CTX_set_cert_cb(3), ssl(7)

       Copyright 2015-2018 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

1.1.1h				  2020-09-22		    SSL_CHECK_CHAIN(3)


Want to link to this manual page? Use this URL:

home | help