SSL_CTX_set_max_cert_list 3 2003-07-24 0.9.9-dev OpenSSL

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

LIBRARY

libcrypto, -lcrypto

SYNOPSIS


 #include 


 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

_S_S_L___C_T_X___s_e_t___m_a_x___c_e_r_t___l_i_s_t_(_) sets the maximum size allowed for the peer's certificate chain for all SSL objects created from ccttxx to be bytes. The SSL objects inherit the setting valid for ccttxx at the time _S_S_L___n_e_w(3) is being called.

_S_S_L___C_T_X___g_e_t___m_a_x___c_e_r_t___l_i_s_t_(_) returns the currently set maximum size for ccttxx.

_S_S_L___s_e_t___m_a_x___c_e_r_t___l_i_s_t_(_) sets the maximum size allowed for the peer's certificate chain for ssssll to be bytes. This setting stays valid until a new value is set.

_S_S_L___g_e_t___m_a_x___c_e_r_t___l_i_s_t_(_) returns the currently set maximum size for ssssll.

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 _S_S_L___C_T_X___s_e_t___v_e_r_i_f_y(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

_S_S_L___C_T_X___s_e_t___m_a_x___c_e_r_t___l_i_s_t_(_) and _S_S_L___s_e_t___m_a_x___c_e_r_t___l_i_s_t_(_) return the previously set value.

_S_S_L___C_T_X___g_e_t___m_a_x___c_e_r_t___l_i_s_t_(_) and _S_S_L___g_e_t___m_a_x___c_e_r_t___l_i_s_t_(_) return the currently set value.

SEE ALSO

_s_s_l(3), _S_S_L___n_e_w(3), _S_S_L___C_T_X___s_e_t___v_e_r_i_f_y(3)

HISTORY

SSL*_set/_g_e_t___m_a_x___c_e_r_t___l_i_s_t_(_) have been introduced in OpenSSL 0.9.7.