Add entropy pool and strong random number generator

Entropy pool gathers environmental noise from device drivers, user-space, etc., and returns good random numbers, suitable for cryptographic use. Based on entropy pool design from *BSDs and uses BLAKE2Xs algorithm for CSPRNG output. Patch also adds /dev/urandom support for using entropy pool RNG and new 'getrandom' system call for getting randomness without file-descriptor usage (thus avoiding file-descriptor exhaustion attacks). The 'getrandom' interface is similar as 'getentropy' and 'getrandom' available on OpenBSD and Linux respectively.
2026-05-21 04:52:02 +08:00 · 2017-03-30 07:38:37 -06:00
parent 21545ab643
commit dffb8a67e3
50 changed files with 2005 additions and 9 deletions
@@ -0,0 +1,77 @@
+/****************************************************************************
+ * include/sys/random.h
+ *
+ *   Copyright (C) 2015-2017 Haltian Ltd. All rights reserved.
+ *   Authors: Juha Niskanen <juha.niskanen@haltian.com>
+ *            Jussi Kivilinna <jussi.kivilinna@haltian.com>
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. 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.
+ * 3. Neither the name NuttX 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 OWNER 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.
+ *
+ ****************************************************************************/
+
+#ifndef __INCLUDE_SYS_RANDOM_H
+#define __INCLUDE_SYS_RANDOM_H
+
+/****************************************************************************
+ * Included Files
+ ****************************************************************************/
+
+#include <nuttx/config.h>
+#include <stddef.h>
+
+/****************************************************************************
+ * Public Function Prototypes
+ ****************************************************************************/
+
+#ifdef CONFIG_CRYPTO_RANDOM_POOL
+
+/****************************************************************************
+ * Function: getrandom
+ *
+ * Description:
+ *   Fill a buffer of arbitrary length with randomness. This is the
+ *   preferred interface for getting random numbers. The traditional
+ *   /dev/random approach is susceptible for things like the attacker
+ *   exhausting file descriptors on purpose.
+ *
+ *   Note that this function cannot fail, other than by asserting.
+ *
+ * Parameters:
+ *   bytes  - Buffer for returned random bytes
+ *   nbytes - Number of bytes requested.
+ *
+ * Returned Value:
+ *   None
+ *
+ ****************************************************************************/
+
+void getrandom(FAR void *bytes, size_t nbytes);
+
+#endif /* CONFIG_CRYPTO_RANDOM_POOL */
+
+#endif /* __INCLUDE_SYS_RANDOM_H */