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
#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);
SSL_CTX_set_max_cert_list() 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.
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.
SSL_CTX_set_max_cert_list() 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.
ssl(7),
SSL_new(3),
SSL_CTX_set_verify(3)
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>.