Lines Matching +full:valid +full:- +full:sources

1 /*-
2  * SPDX-License-Identifier: BSD-2-Clause
33  * It is also inspired by DJB's writing on buffered key-erasure PRNGs:
34  * https://blog.cr.yp.to/20170723-random.html
38  *  - Extended to multi-CPU design
39  *  - Extended to pre-buffer some PRNG output
40  *  - Pool-based reseeding is solely time-based (rather than on-access w/
42  *  - Extended to specify efficient userspace design
43  *  - Always-available design (requires the equivalent of loader(8) for all
49  *  - Relationship between root PRNG seed version and periodic reseed pool use.
53  *    don't think first-time entropy sources should cause us to skip an entropy
55  *  - Initial seeding.  The paper is pretty terse on the subject.  My
57  *    relies on the loader(8)-provided material for initial seeding and either
58  *    ignores or doesn't start entropy sources until after that time.  So when
59  *    the paper says that first-time entropy source material "bypasses the
61  *    can generate 256 bits, mix it with the first-time entropy, and reseed
66  *  - Blake2b instead of SHA-2 512 for entropy pooling
67  *  - Chacha20 instead of AES-CTR DRBG for PRF
68  *  - Initial seeding.  We treat the 0->1 seed version (brng_generation) edge
77  *    • All one-off sources are fed into pool0 and the result used to seed the
82  *      present one-off source, to the extent it is in the control of
84  * - Timer interval reseeding.  We also start the timer-based reseeding at
86  *   load (usually within the order of micro- or milliseconds due to
91  *  - Various initial seeding sources we don't have yet
92  *  - In particular, VM migration/copy detection
133  * Top-level read API from randomdev.  Responsible for NOWAIT-allocating
134  * per-cpu NUMA-local BRNGs, if needed and satisfiable; subroutines handle
136  * low-memory conditions when a local BRNG cannot be allocated, the request is
155 	pcpu_brng_p = _DPCPU_PTR(pcpu->pc_dynamic, fxrng_brng);  in _fxrng_alg_read()
161 	 * on-demand and need to check first.  BRNGs are never deallocated and  in _fxrng_alg_read()
162 	 * are valid as soon as the pointer is initialized.  in _fxrng_alg_read()
169 		domain = pcpu->pc_domain;  in _fxrng_alg_read()
172 		 * Allocate pcpu BRNGs off-domain on weird NUMA machines like  in _fxrng_alg_read()
178 		 * Otherwise, allocate strictly CPU-local memory.  The  in _fxrng_alg_read()
210 		/* Establish lock order root->pcpu for WITNESS. */  in _fxrng_alg_read()
215 		    sizeof(newkey), &rng->brng_generation);  in _fxrng_alg_read()
218 		fxrng_rng_setkey(&rng->brng_rng, newkey, sizeof(newkey));  in _fxrng_alg_read()
222 		 * We have a valid RNG.  Try to install it, or grab the other  in _fxrng_alg_read()
236 		 * state -- it has already rekeyed.  The generation  in _fxrng_alg_read()
247 	/* At this point we have a valid, initialized and seeded rng pointer. */  in _fxrng_alg_read()
250 		*seed_version_out = rng->brng_generation;  in _fxrng_alg_read()