/*
* rpc_misc.c
* ----------
* RPC interface to TRNG and PIN functions
*
* Authors: Rob Austein
* Copyright (c) 2015, NORDUnet A/S All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions are
* met:
* - Redistributions of source code must retain the above copyright notice,
* this list of conditions and the following disclaimer.
*
* - Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* - Neither the name of the NORDUnet nor the names of its contributors may
* be used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS
* IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
* TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A
* PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
* HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED
* TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
* PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
* LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
* NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
* SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
#include <assert.h>
#include "hal.h"
#include "hal_internal.h"
static hal_error_t get_random(void *buffer, const size_t length)
{
assert(buffer != NULL && length > 0);
return hal_get_random(NULL, buffer, length);
}
/*
* PINs, salt, and iteration count live in the keystore.
*
* We also need a client table in conventional memory (here, probably)
* to record login status.
*
* The USER and SO PINs correspond to PKCS #11.
*
* The WHEEL PIN is the one that's allowed to change the SO PIN.
*
* It's a bit unclear how we should manage changes to the WHEEL PIN.
* Implementing a factory default would be easy enough (just
* pre-compute and compile in a const hal_ks_pin_t), question is
* whether doing so provides anything useful. Certainly adds no real
* security, question is whether it would help prevent accidently
* bricking the HSM right out of the shrink wrap.
*
* More interesting question is whether we should ever allow the WHEEL
* PIN to be changed a second time without toasting the keystore.
*
* We also need a function which the rest of the library can use to
* check current login status for a particular hal_client_t. Don't
* know yet whether we need anything else.
*/
#warning PIN code not yet fully implemented
typedef struct {
hal_client_handle_t handle;
hal_user_t logged_in;
} client_slot_t;
#ifndef HAL_PIN_MINIMUM_ITERATIONS
#define HAL_PIN_MINIMUM_ITERATIONS 10000
#endif
#ifndef HAL_PIN_DEFAULT_ITERATIONS
#define HAL_PIN_DEFAULT_ITERATIONS 20000
#endif
#ifndef HAL_STATIC_CLIENT_STATE_BLOCKS
#define HAL_STATIC_CLIENT_STATE_BLOCKS 10
#endif
#if HAL_STATIC_CLIENT_STATE_BLOCKS > 0
static client_slot_t client_handle[HAL_STATIC_CLIENT_STATE_BLOCKS];
#endif
/*
* Client handles are supplied by the application, we don't get to
* pick them, we just store them and associate a login state with
* them. HAL_USER_NONE indicates an empty slot in the table.
*/
static inline client_slot_t *alloc_slot(void)
{
#if HAL_STATIC_CLIENT_STATE_BLOCKS > 0
for (int i = 0; i < sizeof(client_handle)/sizeof(*client_handle); i++)
if (client_handle[i].logged_in == HAL_USER_NONE)
return &client_handle[i];
#endif
return NULL;
}
static inline client_slot_t *find_handle(const hal_client_handle_t handle)
{
#if HAL_STATIC_CLIENT_STATE_BLOCKS > 0
for (int i = 0; i < sizeof(client_handle)/sizeof(*client_handle); i++)
if (client_handle[i].logged_in != HAL_USER_NONE && client_handle[i].handle.handle == handle.handle)
return &client_handle[i];
#endif
return NULL;
}
static hal_error_t set_pin(const hal_client_handle_t client,
const hal_user_t user,
const char * const newpin, const size_t newpin_len)
{
assert(newpin != NULL && newpin_len != 0);
#warning Need access control to decide who is allowed to set this PIN
#warning Need length checks (here or in caller) on supplied PIN
const hal_ks_pin_t *pp;
hal_error_t err;
if ((err = hal_ks_get_pin(user, &pp)) != HAL_OK)
return err;
hal_ks_pin_t p = *pp;
if (p.iterations == 0)
p.iterations = HAL_PIN_DEFAULT_ITERATIONS;
if ((err = hal_get_random(NULL, p.salt, sizeof(p.salt))) != HAL_OK ||
(err = hal_pbkdf2(NULL, hal_hash_sha256,
(const uint8_t *) newpin, newpin_len,
p.salt, sizeof(p.salt),
p.pin, sizeof(p.pin), p.iterations)) != HAL_OK ||
(err = hal_ks_set_pin(user, &p)) != HAL_OK)
return err;
return HAL_OK;
}
static hal_error_t login(const hal_client_handle_t client,
const hal_user_t user,
const char * const pin, const size_t pin_len)
{
assert(pin != NULL && pin_len != 0);
assert(user == HAL_USER_NORMAL || user == HAL_USER_SO || user == HAL_USER_WHEEL);
const hal_ks_pin_t *p;
hal_error_t err;
if ((err = hal_ks_get_pin(user, &p)) != HAL_OK)
return err;
uint8_t buf[sizeof(p->pin)];
if ((err = hal_pbkdf2(NULL, hal_hash_sha256, (const uint8_t *) pin, pin_len,
p->salt, sizeof(p->salt), buf, sizeof(buf), p->iterations)) != HAL_OK)
return err;
unsigned diff = 0;
for (int i = 0; i < sizeof(buf); i++)
diff |= buf[i] ^ p->pin[i];
if (diff != 0)
return HAL_ERROR_PIN_INCORRECT;
client_slot_t *slot = find_handle(client);
if (slot != NULL && (slot = alloc_slot()) == NULL)
return HAL_ERROR_NO_CLIENT_SLOTS_AVAILABLE;
slot->handle = client;
slot->logged_in = user;
return HAL_OK;
}
static hal_error_t logout(const hal_client_handle_t client)
{
client_slot_t *slot = find_handle(client);
if (slot != NULL)
slot->logged_in = HAL_USER_NONE;
return HAL_OK;
}
const hal_rpc_misc_dispatch_t hal_rpc_remote_misc_dispatch = {
set_pin, login, logout, get_random
};
/*
* Local variables:
* indent-tabs-mode: nil
* End:
*/
