SSL_CTX_SET_MAX_CERT_LIST(3ossl) OpenSSL SSL_CTX_SET_MAX_CERT_LIST(3ossl)
NAME
SSL_CTX_set_max_cert_list, SSL_CTX_get_max_cert_list,
SSL_set_max_cert_list, SSL_get_max_cert_list - manipulate allowed size
for the peer's certificate chain
SYNOPSIS
#include <openssl/ssl.h>
long SSL_CTX_set_max_cert_list(SSL_CTX *ctx, long size);
long SSL_CTX_get_max_cert_list(SSL_CTX *ctx);
long SSL_set_max_cert_list(SSL *ssl, long size);
long SSL_get_max_cert_list(SSL *ctx);
DESCRIPTION
SSL_CTX_set_max_cert_list(3) sets the maximum size allowed for the
peer's certificate chain for all SSL objects created from ctx to be
<size> bytes. The SSL objects inherit the setting valid for ctx at the
time SSL_new(3) is being called.
SSL_CTX_get_max_cert_list() returns the currently set maximum size for
ctx.
SSL_set_max_cert_list() sets the maximum size allowed for the peer's
certificate chain for ssl to be <size> bytes. This setting stays valid
until a new value is set.
SSL_get_max_cert_list() returns the currently set maximum size for ssl.
NOTES
During the handshake process, the peer may send a certificate chain.
The TLS/SSL standard does not give any maximum size of the certificate
chain. The OpenSSL library handles incoming data by a dynamically
allocated buffer. In order to prevent this buffer from growing without
bounds due to data received from a faulty or malicious peer, a maximum
size for the certificate chain is set.
The default value for the maximum certificate chain size is 100kB (30kB
on the 16-bit DOS platform). This should be sufficient for usual
certificate chains (OpenSSL's default maximum chain length is 10, see
SSL_CTX_set_verify(3), and certificates without special extensions have
a typical size of 1-2kB).
For special applications it can be necessary to extend the maximum
certificate chain size allowed to be sent by the peer, see e.g. the
work on "Internet X.509 Public Key Infrastructure Proxy Certificate
Profile" and "TLS Delegation Protocol" at http://www.ietf.org/ and
http://www.globus.org/ .
Under normal conditions it should never be necessary to set a value
smaller than the default, as the buffer is handled dynamically and only
uses the memory actually required by the data sent by the peer.
If the maximum certificate chain size allowed is exceeded, the
handshake will fail with a SSL_R_EXCESSIVE_MESSAGE_SIZE error.
RETURN VALUES
SSL_CTX_set_max_cert_list(3) and SSL_set_max_cert_list() return the
previously set value.
SSL_CTX_get_max_cert_list() and SSL_get_max_cert_list() return the
currently set value.
SEE ALSO
ssl(7), SSL_new(3), SSL_CTX_set_verify(3)
COPYRIGHT
Copyright 2001-2020 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
<https://www.openssl.org/source/license.html>.
3.3.2 2024-09-04 SSL_CTX_SET_MAX_CERT_LIST(3ossl)
openssl 3.3.2 - Generated Tue Sep 24 07:25:01 CDT 2024