From 252c90732709447ad33bbf329fc47d584cd23f37 Mon Sep 17 00:00:00 2001 From: Alex Funo Date: Wed, 9 Jul 2025 20:18:22 +0700 Subject: kernel: dev: Add /dev/random Introduce a prototype cryptographically secure (?) random number generator. The RNG uses ChaCha20 seeded with a SipHash-processed entropy pool. Entropy is collected only at read time and is mixed into the internal pool before each ChaCha20 reseed. The design is still experimental. Signed-off-by: Alex Funo Signed-off-by: Ian Moffett --- sys/dev/random/entropy.c | 55 ++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 55 insertions(+) create mode 100644 sys/dev/random/entropy.c (limited to 'sys/dev/random/entropy.c') diff --git a/sys/dev/random/entropy.c b/sys/dev/random/entropy.c new file mode 100644 index 0000000..d392b9c --- /dev/null +++ b/sys/dev/random/entropy.c @@ -0,0 +1,55 @@ +/* + * Copyright (c) 2023-2025 Ian Marco Moffett and the Osmora Team. + * All rights reserved. + * + * 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 of Hyra 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. + */ + +#include +#include +#include +#include + +void +mix_entropy(struct entropy_pool *ep, const uint8_t *input, + size_t input_len, uint32_t input_entropy_bits) +{ + char key[16] = {0,1,2,3,4,5,6,7,8,9,0xa,0xb,0xc,0xd,0xe,0xf}; + uint64_t hash_result; + uint8_t buffer[ENTROPY_POOL_SIZE + input_len]; + memcpy(buffer, ep->pool, ENTROPY_POOL_SIZE); + memcpy(buffer + ENTROPY_POOL_SIZE, input, input_len); + + hash_result = siphash24(buffer, sizeof(buffer), key); + + for (int i = 0; i < 8; ++i) { + ep->pool[i] ^= (hash_result >> (i * 8)) & 0xFF; + } + + ep->entropy_bits += input_entropy_bits; + if (ep->entropy_bits > ENTROPY_POOL_SIZE * 8) { + ep->entropy_bits = ENTROPY_POOL_SIZE * 8; + } +} -- cgit v1.2.3