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/* Copyright (C) 2017 CZ.NIC, z.s.p.o. <knot-dns@labs.nic.cz>
This program is free software: you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation, either version 3 of the License, or
(at your option) any later version.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
/*!
* \file
*
* \brief TSIG signing and validating.
*
* \addtogroup knot-tsig
* @{
*/
#pragma once
#include <stdint.h>
#include "libknot/rrtype/tsig.h"
#include "libknot/rrset.h"
/*!
* \brief Generate TSIG signature of a message.
*
* This function generates TSIG digest of the given message prepended with the
* given Request MAC (if any) and appended with TSIG Variables. It also appends
* the resulting TSIG RR to the message wire format and accordingly adjusts
* the message size.
*
* \note This function does not save the new digest to the 'digest' parameter
* unless everything went OK. This allows sending the same buffer to
* the 'request_mac' and 'digest' parameters.
*
* \param msg Message to be signed.
* \param msg_len Size of the message in bytes.
* \param msg_max_len Maximum size of the message in bytes.
* \param request_mac Request MAC. (may be NULL).
* \param request_mac_len Size of the request MAC in bytes.
* \param digest Buffer to save the digest in.
* \param digest_len In: size of the buffer. Out: real size of the digest saved.
* \param key TSIG used for signing.
* \param tsig_rcode RCODE of the TSIG.
* \param request_time_signed Clients time signed.
*
* \retval KNOT_EOK if everything went OK.
* \retval TODO
*
* \todo This function should return TSIG errors by their codes which are
* positive values - this will be recognized by the caller.
*/
int knot_tsig_sign(uint8_t *msg, size_t *msg_len, size_t msg_max_len,
const uint8_t *request_mac, size_t request_mac_len,
uint8_t *digest, size_t *digest_len,
const knot_tsig_key_t *key, uint16_t tsig_rcode,
uint64_t request_time_signed);
/*!
* \brief Generate TSIG signature of a 2nd or later message in a TCP session.
*
* This function generates TSIG digest of the given message prepended with the
* given Request MAC (if any) and appended with TSIG Variables. It also appends
* the resulting TSIG RR to the message wire format and accordingly adjusts
* the message size.
*
* \note This function does not save the new digest to the 'digest' parameter
* unless everything went OK. This allows sending the same buffer to
* the 'request_mac' and 'digest' parameters.
*
* \param msg Message to be signed.
* \param msg_len Size of the message in bytes.
* \param msg_max_len Maximum size of the message in bytes.
* \param prev_digest Previous digest sent by the server in the session.
* \param prev_digest_len Size of the previous digest in bytes.
* \param digest Buffer to save the digest in.
* \param digest_len In: size of the buffer. Out: real size of the digest saved.
* \param key TSIG key for signing.
* \param to_sign Data being signed.
* \param to_sign_len Size of the data being signed.
*
* \retval KNOT_EOK if successful.
* \retval TODO
*
* \todo This function should return TSIG errors by their codes which are
* positive values - this will be recognized by the caller.
*/
int knot_tsig_sign_next(uint8_t *msg, size_t *msg_len, size_t msg_max_len,
const uint8_t *prev_digest, size_t prev_digest_len,
uint8_t *digest, size_t *digest_len,
const knot_tsig_key_t *key, uint8_t *to_sign,
size_t to_sign_len);
/*!
* \brief Checks incoming request.
*
* \param tsig_rr TSIG extracted from the packet.
* \param wire Wire format of the packet (including the TSIG RR).
* \param size Size of the wire format of packet in bytes.
* \param tsig_key TSIG key.
*
* \retval KNOT_EOK If the signature is valid.
* \retval TODO
*
* \todo This function should return TSIG errors by their codes which are
* positive values - this will be recognized by the caller.
*/
int knot_tsig_server_check(const knot_rrset_t *tsig_rr,
const uint8_t *wire, size_t size,
const knot_tsig_key_t *tsig_key);
/*!
* \brief Checks incoming response.
*
* \param tsig_rr TSIG extracted from the packet.
* \param wire Wire format of the packet (including the TSIG RR).
* \param size Size of the wire format of packet in bytes.
* \param request_mac Request MAC. (may be NULL).
* \param request_mac_len Size of the request MAC in bytes.
* \param key TSIG key.
* \param prev_time_signed Time for TSIG period validity.
*
* \retval KNOT_EOK If the signature is valid.
* \retval TODO
*
* \todo This function should return TSIG errors by their codes which are
* positive values - this will be recognized by the caller.
*/
int knot_tsig_client_check(const knot_rrset_t *tsig_rr,
const uint8_t *wire, size_t size,
const uint8_t *request_mac, size_t request_mac_len,
const knot_tsig_key_t *key,
uint64_t prev_time_signed);
/*!
* \brief Checks signature of 2nd or next packet in a TCP session.
*
* \param tsig_rr TSIG extracted from the packet.
* \param wire Wire format of the packet (including the TSIG RR).
* \param size Size of the wire format of packet in bytes.
* \param prev_digest Previous digest sent by the server in the session.
* \param prev_digest_len Size of the previous digest in bytes.
* \param key TSIG key.
* \param prev_time_signed Time for TSIG period validity.
*
* \retval KNOT_EOK If the signature is valid.
* \retval TODO
*
* \todo This function should return TSIG errors by their codes which are
* positive values - this will be recognized by the caller.
*/
int knot_tsig_client_check_next(const knot_rrset_t *tsig_rr,
const uint8_t *wire, size_t size,
const uint8_t *prev_digest,
size_t prev_digest_len,
const knot_tsig_key_t *key,
uint64_t prev_time_signed);
/*!
* \todo Documentation!
*/
int knot_tsig_add(uint8_t *msg, size_t *msg_len, size_t msg_max_len,
uint16_t tsig_rcode, const knot_rrset_t *tsig_rr);
/*! \brief Append TSIG RR to message.
* \todo Proper documentation.
*/
int knot_tsig_append(uint8_t *msg, size_t *msg_len, size_t msg_max_len,
const knot_rrset_t *tsig_rr);
/*! \brief Return true if the TSIG RCODE allows signing the packet.
* \todo Proper documentation.
*/
static inline bool knot_tsig_can_sign(uint16_t tsig_rcode) {
return tsig_rcode == KNOT_RCODE_NOERROR || tsig_rcode == KNOT_RCODE_BADTIME;
}
/*! @} */
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