RPC interface to TRNG and (incomplete) PIN code.

1 files changed, 158 insertions, 0 deletions

diff --git a/rpc_misc.c b/rpc_misc.c
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+/*
+ * 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
+
+#ifndef HAL_PIN_MINIMUM_ITERATIONS
+#define HAL_PIN_MINIMUM_ITERATIONS 10000
+#endif
+
+#ifndef HAL_PIN_DEFAULT_ITERATIONS
+#define HAL_PIN_DEFAULT_ITERATIONS 20000
+#endif
+
+static hal_error_t set_pin(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 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;
+
+#warning Do something with client table here
+
+  return HAL_OK;
+}
+
+static hal_error_t logout(const hal_client_handle_t client)
+{
+#warning And do something else with client table here
+  return HAL_ERROR_IMPOSSIBLE;
+}
+
+const hal_rpc_misc_dispatch_t hal_rpc_remote_misc_dispatch = {
+  set_pin, login, logout, get_random
+};
+
+/*
+ * Local variables:
+ * indent-tabs-mode: nil
+ * End:
+ */