long SSL_CTX_set_tlsext_ticket_key_cb(SSL_CTX sslctx,
int (*cb)(SSL *s, unsigned char key_name[16],
- unsigned char iv[EVP_MAX_IV_LENGTH],
- EVP_CIPHER_CTX *ctx, HMAC_CTX *hctx, int enc));
+ unsigned char iv[EVP_MAX_IV_LENGTH],
+ EVP_CIPHER_CTX *ctx, HMAC_CTX *hctx, int enc));
=head1 DESCRIPTION
SSL_CTX_set_tlsext_ticket_key_cb() sets a callback function I<cb> for handling
-session tickets for the ssl context I<sslctx>. Session tickets, defined in
+session tickets for the ssl context I<sslctx>. Session tickets, defined in
RFC5077 provide an enhanced session resumption capability where the server
implementation is not required to maintain per session state. It only applies
to TLS and there is no SSLv3 implementation.
message. It is the responsibility of this function to create or retrieve the
cryptographic parameters and to maintain their state.
-The OpenSSL library uses your callback function to help implement a common TLS
+The OpenSSL library uses your callback function to help implement a common TLS
ticket construction state according to RFC5077 Section 4 such that per session
-state is unnecessary and a small set of cryptographic variables needs to be
+state is unnecessary and a small set of cryptographic variables needs to be
maintained by the callback function implementation.
In order to reuse a session, a TLS client must send the a session ticket
The I<name> is 16 characters long and is used as a key identifier.
The I<iv> length is the length of the IV of the corresponding cipher. The
-maximum IV length is L<EVP_MAX_IV_LENGTH> bytes defined in B<evp.h>.
+maximum IV length is B<EVP_MAX_IV_LENGTH> bytes defined in B<evp.h>.
The initialization vector I<iv> should be a random value. The cipher context
I<ctx> should use the initialisation vector I<iv>. The cipher context can be
-set using L<EVP_EncryptInit_ex>. The hmac context can be set using L<HMAC_Init_ex>.
+set using L<EVP_EncryptInit_ex(3)>. The hmac context can be set using
+L<HMAC_Init_ex(3)>.
-When the client presents a session ticket, the callback function with be called
+When the client presents a session ticket, the callback function with be called
with I<enc> set to 0 indicating that the I<cb> function should retrieve a set
of parameters. In this case I<name> and I<iv> have already been parsed out of
the session ticket. The OpenSSL library expects that the I<name> will be used
to retrieve a cryptographic parameters and that the cryptographic context
I<ctx> will be set with the retrieved parameters and the initialization vector
-I<iv>. using a function like L<EVP_DecryptInit_ex>. The I<hctx> needs to be set
-using L<HMAC_Init_ex>.
+I<iv>. using a function like L<EVP_DecryptInit_ex(3)>. The I<hctx> needs to be
+set using L<HMAC_Init_ex(3)>.
If the I<name> is still valid but a renewal of the ticket is required the
callback function should return 2. The library will call the callback again
=item Z<>2
-This indicates that the I<ctx> and I<hctx> have been set and the session can
+This indicates that the I<ctx> and I<hctx> have been set and the session can
continue on those parameters. Additionally it indicates that the session
ticket is in a renewal period and should be replaced. The OpenSSL library will
call I<cb> again with an enc argument of 1 to set the new ticket (see RFC5077
=item Z<>1
-This indicates that the I<ctx> and I<hctx> have been set and the session can
+This indicates that the I<ctx> and I<hctx> have been set and the session can
continue on those parameters.
=item Z<>0
-This indicates that it was not possible to set/retrieve a session ticket and
-the SSL/TLS session will continue by by negotiating a set of cryptographic
+This indicates that it was not possible to set/retrieve a session ticket and
+the SSL/TLS session will continue by negotiating a set of cryptographic
parameters or using the alternate SSL/TLS resumption mechanism, session ids.
If called with enc equal to 0 the library will call the I<cb> again to get
if (RAND_bytes(iv, EVP_MAX_IV_LENGTH) ) {
return -1; /* insufficient random */
}
-
+
key = currentkey(); /* something that you need to implement */
if ( !key ) {
/* current key doesn't exist or isn't valid */
}
}
memcpy(key_name, key->name, 16);
-
+
EVP_EncryptInit_ex(&ctx, EVP_aes_128_cbc(), NULL, key->aes_key, iv);
HMAC_Init_ex(&hctx, key->hmac_key, 16, EVP_sha256(), NULL);
-
+
return 1;
-
+
} else { /* retrieve session */
key = findkey(name);
-
+
if (!key || key->expire < now() ) {
return 0;
}
-
+
HMAC_Init_ex(&hctx, key->hmac_key, 16, EVP_sha256(), NULL);
EVP_DecryptInit_ex(&ctx, EVP_aes_128_cbc(), NULL, key->aes_key, iv );
return 2;
}
return 1;
-
+
}
}
L<SSL_CTX_sess_set_get_cb(3)>,
L<SSL_CTX_set_session_id_context(3)>,
+=head1 COPYRIGHT
+
+Copyright 2014-2016 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
projects / openssl.git / blobdiff