xref: /freebsd/sys/dev/random/fenestrasX/fx_brng.h (revision b17b639832e707aab0e9514cf94727498e2d67bd)
1 /*-
2  * SPDX-License-Identifier: BSD-2-Clause
3  *
4  * Copyright (c) 2019 Conrad Meyer <cem@FreeBSD.org>
5  *
6  * Redistribution and use in source and binary forms, with or without
7  * modification, are permitted provided that the following conditions
8  * are met:
9  * 1. Redistributions of source code must retain the above copyright
10  *    notice, this list of conditions and the following disclaimer.
11  * 2. Redistributions in binary form must reproduce the above copyright
12  *    notice, this list of conditions and the following disclaimer in the
13  *    documentation and/or other materials provided with the distribution.
14  *
15  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
16  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
17  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
18  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
19  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
20  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
21  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
22  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
23  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
24  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
25  * SUCH DAMAGE.
26  *
27  * $FreeBSD$
28  */
29 #pragma once
30 
31 #include <dev/random/fenestrasX/fx_rng.h>
32 
33 #define	FXRNG_BUFRNG_SZ	128
34 
35 /*
36  * An object representing a buffered random number generator with forward
37  * secrecy (aka "fast-key-erasure").
38  *
39  * There is a single static root instance of this object associated with the
40  * entropy harvester, as well as additional instances per CPU, lazily allocated
41  * in NUMA-local memory, seeded from output of the root generator.
42  */
43 struct fxrng_buffered_rng {
44 	struct fxrng_basic_rng	brng_rng;
45 #define	FXRNG_BRNG_LOCK(brng)	mtx_lock(&(brng)->brng_rng.rng_lk)
46 #define	FXRNG_BRNG_UNLOCK(brng)	mtx_unlock(&(brng)->brng_rng.rng_lk)
47 #define	FXRNG_BRNG_ASSERT(brng)	mtx_assert(&(brng)->brng_rng.rng_lk, MA_OWNED)
48 #define	FXRNG_BRNG_ASSERT_NOT(brng) \
49 	mtx_assert(&(brng)->brng_rng.rng_lk, MA_NOTOWNED)
50 
51 	/* Entropy reseed generation ("seed version"). */
52 	uint64_t	brng_generation;
53 
54 	/* Buffered output for quick access by small requests. */
55 	uint8_t		brng_buffer[FXRNG_BUFRNG_SZ];
56 	uint8_t		brng_avail_idx;
57 };
58 
59 void fxrng_brng_init(struct fxrng_buffered_rng *);
60 void fxrng_brng_produce_seed_data_internal(struct fxrng_buffered_rng *, void *,
61     size_t, uint64_t *seed_generation);
62 void fxrng_brng_read(struct fxrng_buffered_rng *, void *, size_t);
63 
64 void fxrng_brng_reseed(const void *, size_t);
65 struct harvest_event;
66 void fxrng_brng_src_reseed(const struct harvest_event *);
67