Import OpenSSL 1.1.0f

doc/ssl/SSL_get_client_random.pod

@@ -0,0 +1,88 @@
+=pod
+
+=head1 NAME
+
+SSL_get_client_random, SSL_get_server_random, SSL_SESSION_get_master_key - retrieve internal TLS/SSL random values and master key
+
+=head1 SYNOPSIS
+
+ #include <openssl/ssl.h>
+
+ size_t SSL_get_client_random(const SSL *ssl, unsigned char *out, size_t outlen);
+ size_t SSL_get_server_random(const SSL *ssl, unsigned char *out, size_t outlen);
+ size_t SSL_SESSION_get_master_key(const SSL_SESSION *session, unsigned char *out, size_t outlen);
+
+=head1 DESCRIPTION
+
+SSL_get_client_random() extracts the random value sent from the client
+to the server during the initial SSL/TLS handshake.  It copies as many
+bytes as it can of this value into the buffer provided in B<out>,
+which must have at least B<outlen> bytes available. It returns the
+total number of bytes that were actually copied.  If B<outlen> is
+zero, SSL_get_client_random() copies nothing, and returns the
+total size of the client_random value.
+
+SSL_get_server_random() behaves the same, but extracts the random value
+sent from the server to the client during the initial SSL/TLS handshake.
+
+SSL_SESSION_get_master_key() behaves the same, but extracts the master
+secret used to guarantee the security of the SSL/TLS session.  This one
+can be dangerous if misused; see NOTES below.
+
+
+=head1 NOTES
+
+You probably shouldn't use these functions.
+
+These functions expose internal values from the TLS handshake, for
+use in low-level protocols.  You probably should not use them, unless
+you are implementing something that needs access to the internal protocol
+details.
+
+Despite the names of SSL_get_client_random() and SSL_get_server_random(), they
+ARE NOT random number generators.  Instead, they return the mostly-random values that
+were already generated and used in the TLS protocol.  Using them
+in place of RAND_bytes() would be grossly foolish.
+
+The security of your TLS session depends on keeping the master key secret:
+do not expose it, or any information about it, to anybody.
+If you need to calculate another secret value that depends on the master
+secret, you should probably use SSL_export_keying_material() instead, and
+forget that you ever saw these functions.
+
+In current versions of the TLS protocols, the length of client_random
+(and also server_random) is always SSL3_RANDOM_SIZE bytes. Support for
+other outlen arguments to the SSL_get_*_random() functions is provided
+in case of the unlikely event that a future version or variant of TLS
+uses some other length there.
+
+Finally, though the "client_random" and "server_random" values are called
+"random", many TLS implementations will generate four bytes of those
+values based on their view of the current time.
+
+
+=head1 RETURN VALUES
+
+If B<outlen> is greater than 0, these functions return the number of bytes
+actually copied, which will be less than or equal to B<outlen>.
+
+If B<outlen> is 0, these functions return the maximum number
+of bytes they would copy--that is, the length of the underlying field.
+
+=head1 SEE ALSO
+
+L<ssl(3)>,
+L<RAND_bytes(3)>,
+L<SSL_export_keying_material(3)>
+
+
+=head1 COPYRIGHT
+
+Copyright 2015-2016 The OpenSSL Project Authors. All Rights Reserved.
+
+Licensed under the OpenSSL license (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
+L<https://www.openssl.org/source/license.html>.
+
+=cut