xref: /freebsd/secure/lib/libcrypto/man/man3/SSL_CTX_set_max_cert_list.3 (revision d4033e6d37747f5213bb245c8e605406703a8766)
-*- mode: troff; coding: utf-8 -*-
Automatically generated by Pod::Man 5.0102 (Pod::Simple 3.45)

Standard preamble:
========================================================================
..
..
.. \*(C` and \*(C' are quotes in nroff, nothing in troff, for use with C<>.
. ds C` "" . ds C' "" 'br\} . ds C` . ds C' 'br\}
Escape single quotes in literal strings from groff's Unicode transform.

If the F register is >0, we'll generate index entries on stderr for
titles (.TH), headers (.SH), subsections (.SS), items (.Ip), and index
entries marked with X<> in POD. Of course, you'll have to process the
output yourself in some meaningful fashion.

Avoid warning from groff about undefined register 'F'.
.. .nr rF 0 . if \nF \{\ . de IX . tm Index:\\$1\t\\n%\t"\\$2" .. . if !\nF==2 \{\ . nr % 0 . nr F 2 . \} . \} .\} .rr rF ========================================================================

Title "SSL_CTX_SET_MAX_CERT_LIST 3ossl"
SSL_CTX_SET_MAX_CERT_LIST 3ossl 2025-09-30 3.5.4 OpenSSL
For nroff, turn off justification. Always turn off hyphenation; it makes
way too many mistakes in technical documents.
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
Header "SYNOPSIS" .Vb 1 #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); .Ve
DESCRIPTION
Header "DESCRIPTION" \fBSSL_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 \fBSSL_new\|(3) is being called.

\fBSSL_CTX_get_max_cert_list() returns the currently set maximum size for ctx.

\fBSSL_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.

\fBSSL_get_max_cert_list() returns the currently set maximum size for ssl.

NOTES
Header "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 \fBSSL_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 an SSL_R_EXCESSIVE_MESSAGE_SIZE error.

"RETURN VALUES"
Header "RETURN VALUES" \fBSSL_CTX_set_max_cert_list() and SSL_set_max_cert_list() return the previously set value.

\fBSSL_CTX_get_max_cert_list() and SSL_get_max_cert_list() return the currently set value.

"SEE ALSO"
Header "SEE ALSO" \fBssl\|(7), SSL_new\|(3), \fBSSL_CTX_set_verify\|(3)
COPYRIGHT
Header "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>.