SSL_CTX_SET_MAX_CERT_... BSD Library Functions Manual SSL_CTX_SET_MAX_CERT_...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);
DESCRIPTIONSSL_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 cer‐
tificate 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 buf‐
fer. In order to prevent this buffer from growing without bound 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 16bit DOS platform). This should be sufficient for usual certifi‐
cate 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 cer‐
tificate chain size allowed to be sent by the peer. See for example 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 VALUESSSL_CTX_set_max_cert_list() and SSL_set_max_cert_list() return the previ‐
ously set value.
SSL_CTX_get_max_cert_list() and SSL_get_max_cert_list() return the cur‐
rently set value.
SEE ALSOssl(3), SSL_CTX_set_verify(3), SSL_new(3)HISTORY
SSL*_set/get_max_cert_list() were introduced in OpenSSL 0.9.7.
BSD April 26, 2024 BSD
