/xlv3/openssl/0.9.7e-sgipl1/work/0.9.7e-sgipl1/openssl-
0.9.7e/doc/ssl
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SSL_CTX_set_max_cert_li11/Sep/2001 (0SSL_CTX_set_max_cert_list(3)
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 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() 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 16bit 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
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SSL_CTX_set_max_cert_li11/Sep/2001 (0SSL_CTX_set_max_cert_list(3)
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() 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(3), SSL_new(3), SSL_CTX_set_verify(3)
HISTORY
SSL*_set/get_max_cert_list() have been introduced in OpenSSL
0.9.7.
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