^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1) // SPDX-License-Identifier: GPL-2.0
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2) /*
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 3) * This is a maximally equidistributed combined Tausworthe generator
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 4) * based on code from GNU Scientific Library 1.5 (30 Jun 2004)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 5) *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 6) * lfsr113 version:
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 7) *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 8) * x_n = (s1_n ^ s2_n ^ s3_n ^ s4_n)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 9) *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 10) * s1_{n+1} = (((s1_n & 4294967294) << 18) ^ (((s1_n << 6) ^ s1_n) >> 13))
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 11) * s2_{n+1} = (((s2_n & 4294967288) << 2) ^ (((s2_n << 2) ^ s2_n) >> 27))
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 12) * s3_{n+1} = (((s3_n & 4294967280) << 7) ^ (((s3_n << 13) ^ s3_n) >> 21))
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 13) * s4_{n+1} = (((s4_n & 4294967168) << 13) ^ (((s4_n << 3) ^ s4_n) >> 12))
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 14) *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 15) * The period of this generator is about 2^113 (see erratum paper).
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 16) *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 17) * From: P. L'Ecuyer, "Maximally Equidistributed Combined Tausworthe
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 18) * Generators", Mathematics of Computation, 65, 213 (1996), 203--213:
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 19) * http://www.iro.umontreal.ca/~lecuyer/myftp/papers/tausme.ps
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 20) * ftp://ftp.iro.umontreal.ca/pub/simulation/lecuyer/papers/tausme.ps
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 21) *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 22) * There is an erratum in the paper "Tables of Maximally Equidistributed
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 23) * Combined LFSR Generators", Mathematics of Computation, 68, 225 (1999),
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 24) * 261--269: http://www.iro.umontreal.ca/~lecuyer/myftp/papers/tausme2.ps
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 25) *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 26) * ... the k_j most significant bits of z_j must be non-zero,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 27) * for each j. (Note: this restriction also applies to the
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 28) * computer code given in [4], but was mistakenly not mentioned
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 29) * in that paper.)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 30) *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 31) * This affects the seeding procedure by imposing the requirement
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 32) * s1 > 1, s2 > 7, s3 > 15, s4 > 127.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 33) */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 34)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 35) #include <linux/types.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 36) #include <linux/percpu.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 37) #include <linux/export.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 38) #include <linux/jiffies.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 39) #include <linux/random.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 40) #include <linux/sched.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 41) #include <linux/bitops.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 42) #include <asm/unaligned.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 43) #include <trace/events/random.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 44)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 45) /**
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 46) * prandom_u32_state - seeded pseudo-random number generator.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 47) * @state: pointer to state structure holding seeded state.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 48) *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 49) * This is used for pseudo-randomness with no outside seeding.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 50) * For more random results, use prandom_u32().
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 51) */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 52) u32 prandom_u32_state(struct rnd_state *state)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 53) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 54) #define TAUSWORTHE(s, a, b, c, d) ((s & c) << d) ^ (((s << a) ^ s) >> b)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 55) state->s1 = TAUSWORTHE(state->s1, 6U, 13U, 4294967294U, 18U);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 56) state->s2 = TAUSWORTHE(state->s2, 2U, 27U, 4294967288U, 2U);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 57) state->s3 = TAUSWORTHE(state->s3, 13U, 21U, 4294967280U, 7U);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 58) state->s4 = TAUSWORTHE(state->s4, 3U, 12U, 4294967168U, 13U);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 59)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 60) return (state->s1 ^ state->s2 ^ state->s3 ^ state->s4);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 61) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 62) EXPORT_SYMBOL(prandom_u32_state);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 63)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 64) /**
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 65) * prandom_bytes_state - get the requested number of pseudo-random bytes
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 66) *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 67) * @state: pointer to state structure holding seeded state.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 68) * @buf: where to copy the pseudo-random bytes to
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 69) * @bytes: the requested number of bytes
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 70) *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 71) * This is used for pseudo-randomness with no outside seeding.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 72) * For more random results, use prandom_bytes().
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 73) */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 74) void prandom_bytes_state(struct rnd_state *state, void *buf, size_t bytes)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 75) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 76) u8 *ptr = buf;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 77)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 78) while (bytes >= sizeof(u32)) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 79) put_unaligned(prandom_u32_state(state), (u32 *) ptr);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 80) ptr += sizeof(u32);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 81) bytes -= sizeof(u32);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 82) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 83)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 84) if (bytes > 0) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 85) u32 rem = prandom_u32_state(state);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 86) do {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 87) *ptr++ = (u8) rem;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 88) bytes--;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 89) rem >>= BITS_PER_BYTE;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 90) } while (bytes > 0);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 91) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 92) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 93) EXPORT_SYMBOL(prandom_bytes_state);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 94)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 95) static void prandom_warmup(struct rnd_state *state)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 96) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 97) /* Calling RNG ten times to satisfy recurrence condition */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 98) prandom_u32_state(state);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 99) prandom_u32_state(state);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 100) prandom_u32_state(state);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 101) prandom_u32_state(state);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 102) prandom_u32_state(state);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 103) prandom_u32_state(state);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 104) prandom_u32_state(state);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 105) prandom_u32_state(state);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 106) prandom_u32_state(state);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 107) prandom_u32_state(state);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 108) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 109)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 110) void prandom_seed_full_state(struct rnd_state __percpu *pcpu_state)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 111) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 112) int i;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 113)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 114) for_each_possible_cpu(i) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 115) struct rnd_state *state = per_cpu_ptr(pcpu_state, i);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 116) u32 seeds[4];
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 117)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 118) get_random_bytes(&seeds, sizeof(seeds));
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 119) state->s1 = __seed(seeds[0], 2U);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 120) state->s2 = __seed(seeds[1], 8U);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 121) state->s3 = __seed(seeds[2], 16U);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 122) state->s4 = __seed(seeds[3], 128U);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 123)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 124) prandom_warmup(state);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 125) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 126) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 127) EXPORT_SYMBOL(prandom_seed_full_state);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 128)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 129) #ifdef CONFIG_RANDOM32_SELFTEST
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 130) static struct prandom_test1 {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 131) u32 seed;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 132) u32 result;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 133) } test1[] = {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 134) { 1U, 3484351685U },
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 135) { 2U, 2623130059U },
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 136) { 3U, 3125133893U },
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 137) { 4U, 984847254U },
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 138) };
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 139)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 140) static struct prandom_test2 {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 141) u32 seed;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 142) u32 iteration;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 143) u32 result;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 144) } test2[] = {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 145) /* Test cases against taus113 from GSL library. */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 146) { 931557656U, 959U, 2975593782U },
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 147) { 1339693295U, 876U, 3887776532U },
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 148) { 1545556285U, 961U, 1615538833U },
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 149) { 601730776U, 723U, 1776162651U },
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 150) { 1027516047U, 687U, 511983079U },
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 151) { 416526298U, 700U, 916156552U },
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 152) { 1395522032U, 652U, 2222063676U },
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 153) { 366221443U, 617U, 2992857763U },
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 154) { 1539836965U, 714U, 3783265725U },
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 155) { 556206671U, 994U, 799626459U },
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 156) { 684907218U, 799U, 367789491U },
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 157) { 2121230701U, 931U, 2115467001U },
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 158) { 1668516451U, 644U, 3620590685U },
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 159) { 768046066U, 883U, 2034077390U },
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 160) { 1989159136U, 833U, 1195767305U },
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 161) { 536585145U, 996U, 3577259204U },
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 162) { 1008129373U, 642U, 1478080776U },
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 163) { 1740775604U, 939U, 1264980372U },
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 164) { 1967883163U, 508U, 10734624U },
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 165) { 1923019697U, 730U, 3821419629U },
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 166) { 442079932U, 560U, 3440032343U },
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 167) { 1961302714U, 845U, 841962572U },
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 168) { 2030205964U, 962U, 1325144227U },
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 169) { 1160407529U, 507U, 240940858U },
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 170) { 635482502U, 779U, 4200489746U },
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 171) { 1252788931U, 699U, 867195434U },
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 172) { 1961817131U, 719U, 668237657U },
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 173) { 1071468216U, 983U, 917876630U },
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 174) { 1281848367U, 932U, 1003100039U },
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 175) { 582537119U, 780U, 1127273778U },
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 176) { 1973672777U, 853U, 1071368872U },
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 177) { 1896756996U, 762U, 1127851055U },
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 178) { 847917054U, 500U, 1717499075U },
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 179) { 1240520510U, 951U, 2849576657U },
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 180) { 1685071682U, 567U, 1961810396U },
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 181) { 1516232129U, 557U, 3173877U },
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 182) { 1208118903U, 612U, 1613145022U },
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 183) { 1817269927U, 693U, 4279122573U },
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 184) { 1510091701U, 717U, 638191229U },
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 185) { 365916850U, 807U, 600424314U },
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 186) { 399324359U, 702U, 1803598116U },
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 187) { 1318480274U, 779U, 2074237022U },
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 188) { 697758115U, 840U, 1483639402U },
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 189) { 1696507773U, 840U, 577415447U },
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 190) { 2081979121U, 981U, 3041486449U },
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 191) { 955646687U, 742U, 3846494357U },
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 192) { 1250683506U, 749U, 836419859U },
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 193) { 595003102U, 534U, 366794109U },
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 194) { 47485338U, 558U, 3521120834U },
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 195) { 619433479U, 610U, 3991783875U },
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 196) { 704096520U, 518U, 4139493852U },
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 197) { 1712224984U, 606U, 2393312003U },
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 198) { 1318233152U, 922U, 3880361134U },
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 199) { 855572992U, 761U, 1472974787U },
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 200) { 64721421U, 703U, 683860550U },
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 201) { 678931758U, 840U, 380616043U },
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 202) { 692711973U, 778U, 1382361947U },
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 203) { 677703619U, 530U, 2826914161U },
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 204) { 92393223U, 586U, 1522128471U },
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 205) { 1222592920U, 743U, 3466726667U },
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 206) { 358288986U, 695U, 1091956998U },
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 207) { 1935056945U, 958U, 514864477U },
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 208) { 735675993U, 990U, 1294239989U },
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 209) { 1560089402U, 897U, 2238551287U },
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 210) { 70616361U, 829U, 22483098U },
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 211) { 368234700U, 731U, 2913875084U },
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 212) { 20221190U, 879U, 1564152970U },
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 213) { 539444654U, 682U, 1835141259U },
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 214) { 1314987297U, 840U, 1801114136U },
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 215) { 2019295544U, 645U, 3286438930U },
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 216) { 469023838U, 716U, 1637918202U },
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 217) { 1843754496U, 653U, 2562092152U },
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 218) { 400672036U, 809U, 4264212785U },
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 219) { 404722249U, 965U, 2704116999U },
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 220) { 600702209U, 758U, 584979986U },
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 221) { 519953954U, 667U, 2574436237U },
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 222) { 1658071126U, 694U, 2214569490U },
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 223) { 420480037U, 749U, 3430010866U },
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 224) { 690103647U, 969U, 3700758083U },
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 225) { 1029424799U, 937U, 3787746841U },
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 226) { 2012608669U, 506U, 3362628973U },
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 227) { 1535432887U, 998U, 42610943U },
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 228) { 1330635533U, 857U, 3040806504U },
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 229) { 1223800550U, 539U, 3954229517U },
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 230) { 1322411537U, 680U, 3223250324U },
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 231) { 1877847898U, 945U, 2915147143U },
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 232) { 1646356099U, 874U, 965988280U },
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 233) { 805687536U, 744U, 4032277920U },
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 234) { 1948093210U, 633U, 1346597684U },
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 235) { 392609744U, 783U, 1636083295U },
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 236) { 690241304U, 770U, 1201031298U },
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 237) { 1360302965U, 696U, 1665394461U },
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 238) { 1220090946U, 780U, 1316922812U },
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 239) { 447092251U, 500U, 3438743375U },
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 240) { 1613868791U, 592U, 828546883U },
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 241) { 523430951U, 548U, 2552392304U },
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 242) { 726692899U, 810U, 1656872867U },
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 243) { 1364340021U, 836U, 3710513486U },
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 244) { 1986257729U, 931U, 935013962U },
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 245) { 407983964U, 921U, 728767059U },
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 246) };
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 247)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 248) static u32 __extract_hwseed(void)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 249) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 250) unsigned int val = 0;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 251)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 252) (void)(arch_get_random_seed_int(&val) ||
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 253) arch_get_random_int(&val));
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 254)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 255) return val;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 256) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 257)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 258) static void prandom_seed_early(struct rnd_state *state, u32 seed,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 259) bool mix_with_hwseed)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 260) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 261) #define LCG(x) ((x) * 69069U) /* super-duper LCG */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 262) #define HWSEED() (mix_with_hwseed ? __extract_hwseed() : 0)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 263) state->s1 = __seed(HWSEED() ^ LCG(seed), 2U);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 264) state->s2 = __seed(HWSEED() ^ LCG(state->s1), 8U);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 265) state->s3 = __seed(HWSEED() ^ LCG(state->s2), 16U);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 266) state->s4 = __seed(HWSEED() ^ LCG(state->s3), 128U);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 267) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 268)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 269) static int __init prandom_state_selftest(void)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 270) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 271) int i, j, errors = 0, runs = 0;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 272) bool error = false;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 273)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 274) for (i = 0; i < ARRAY_SIZE(test1); i++) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 275) struct rnd_state state;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 276)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 277) prandom_seed_early(&state, test1[i].seed, false);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 278) prandom_warmup(&state);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 279)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 280) if (test1[i].result != prandom_u32_state(&state))
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 281) error = true;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 282) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 283)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 284) if (error)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 285) pr_warn("prandom: seed boundary self test failed\n");
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 286) else
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 287) pr_info("prandom: seed boundary self test passed\n");
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 288)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 289) for (i = 0; i < ARRAY_SIZE(test2); i++) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 290) struct rnd_state state;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 291)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 292) prandom_seed_early(&state, test2[i].seed, false);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 293) prandom_warmup(&state);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 294)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 295) for (j = 0; j < test2[i].iteration - 1; j++)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 296) prandom_u32_state(&state);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 297)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 298) if (test2[i].result != prandom_u32_state(&state))
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 299) errors++;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 300)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 301) runs++;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 302) cond_resched();
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 303) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 304)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 305) if (errors)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 306) pr_warn("prandom: %d/%d self tests failed\n", errors, runs);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 307) else
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 308) pr_info("prandom: %d self tests passed\n", runs);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 309) return 0;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 310) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 311) core_initcall(prandom_state_selftest);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 312) #endif
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 313)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 314) /*
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 315) * The prandom_u32() implementation is now completely separate from the
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 316) * prandom_state() functions, which are retained (for now) for compatibility.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 317) *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 318) * Because of (ab)use in the networking code for choosing random TCP/UDP port
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 319) * numbers, which open DoS possibilities if guessable, we want something
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 320) * stronger than a standard PRNG. But the performance requirements of
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 321) * the network code do not allow robust crypto for this application.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 322) *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 323) * So this is a homebrew Junior Spaceman implementation, based on the
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 324) * lowest-latency trustworthy crypto primitive available, SipHash.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 325) * (The authors of SipHash have not been consulted about this abuse of
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 326) * their work.)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 327) *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 328) * Standard SipHash-2-4 uses 2n+4 rounds to hash n words of input to
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 329) * one word of output. This abbreviated version uses 2 rounds per word
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 330) * of output.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 331) */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 332)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 333) struct siprand_state {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 334) unsigned long v0;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 335) unsigned long v1;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 336) unsigned long v2;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 337) unsigned long v3;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 338) };
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 339)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 340) static DEFINE_PER_CPU(struct siprand_state, net_rand_state) __latent_entropy;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 341) DEFINE_PER_CPU(unsigned long, net_rand_noise);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 342) EXPORT_PER_CPU_SYMBOL(net_rand_noise);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 343)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 344) /*
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 345) * This is the core CPRNG function. As "pseudorandom", this is not used
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 346) * for truly valuable things, just intended to be a PITA to guess.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 347) * For maximum speed, we do just two SipHash rounds per word. This is
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 348) * the same rate as 4 rounds per 64 bits that SipHash normally uses,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 349) * so hopefully it's reasonably secure.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 350) *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 351) * There are two changes from the official SipHash finalization:
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 352) * - We omit some constants XORed with v2 in the SipHash spec as irrelevant;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 353) * they are there only to make the output rounds distinct from the input
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 354) * rounds, and this application has no input rounds.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 355) * - Rather than returning v0^v1^v2^v3, return v1+v3.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 356) * If you look at the SipHash round, the last operation on v3 is
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 357) * "v3 ^= v0", so "v0 ^ v3" just undoes that, a waste of time.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 358) * Likewise "v1 ^= v2". (The rotate of v2 makes a difference, but
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 359) * it still cancels out half of the bits in v2 for no benefit.)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 360) * Second, since the last combining operation was xor, continue the
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 361) * pattern of alternating xor/add for a tiny bit of extra non-linearity.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 362) */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 363) static inline u32 siprand_u32(struct siprand_state *s)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 364) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 365) unsigned long v0 = s->v0, v1 = s->v1, v2 = s->v2, v3 = s->v3;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 366) unsigned long n = raw_cpu_read(net_rand_noise);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 367)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 368) v3 ^= n;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 369) PRND_SIPROUND(v0, v1, v2, v3);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 370) PRND_SIPROUND(v0, v1, v2, v3);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 371) v0 ^= n;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 372) s->v0 = v0; s->v1 = v1; s->v2 = v2; s->v3 = v3;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 373) return v1 + v3;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 374) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 375)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 376)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 377) /**
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 378) * prandom_u32 - pseudo random number generator
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 379) *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 380) * A 32 bit pseudo-random number is generated using a fast
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 381) * algorithm suitable for simulation. This algorithm is NOT
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 382) * considered safe for cryptographic use.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 383) */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 384) u32 prandom_u32(void)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 385) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 386) struct siprand_state *state = get_cpu_ptr(&net_rand_state);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 387) u32 res = siprand_u32(state);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 388)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 389) trace_prandom_u32(res);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 390) put_cpu_ptr(&net_rand_state);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 391) return res;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 392) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 393) EXPORT_SYMBOL(prandom_u32);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 394)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 395) /**
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 396) * prandom_bytes - get the requested number of pseudo-random bytes
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 397) * @buf: where to copy the pseudo-random bytes to
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 398) * @bytes: the requested number of bytes
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 399) */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 400) void prandom_bytes(void *buf, size_t bytes)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 401) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 402) struct siprand_state *state = get_cpu_ptr(&net_rand_state);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 403) u8 *ptr = buf;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 404)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 405) while (bytes >= sizeof(u32)) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 406) put_unaligned(siprand_u32(state), (u32 *)ptr);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 407) ptr += sizeof(u32);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 408) bytes -= sizeof(u32);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 409) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 410)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 411) if (bytes > 0) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 412) u32 rem = siprand_u32(state);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 413)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 414) do {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 415) *ptr++ = (u8)rem;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 416) rem >>= BITS_PER_BYTE;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 417) } while (--bytes > 0);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 418) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 419) put_cpu_ptr(&net_rand_state);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 420) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 421) EXPORT_SYMBOL(prandom_bytes);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 422)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 423) /**
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 424) * prandom_seed - add entropy to pseudo random number generator
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 425) * @entropy: entropy value
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 426) *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 427) * Add some additional seed material to the prandom pool.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 428) * The "entropy" is actually our IP address (the only caller is
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 429) * the network code), not for unpredictability, but to ensure that
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 430) * different machines are initialized differently.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 431) */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 432) void prandom_seed(u32 entropy)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 433) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 434) int i;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 435)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 436) add_device_randomness(&entropy, sizeof(entropy));
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 437)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 438) for_each_possible_cpu(i) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 439) struct siprand_state *state = per_cpu_ptr(&net_rand_state, i);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 440) unsigned long v0 = state->v0, v1 = state->v1;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 441) unsigned long v2 = state->v2, v3 = state->v3;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 442)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 443) do {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 444) v3 ^= entropy;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 445) PRND_SIPROUND(v0, v1, v2, v3);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 446) PRND_SIPROUND(v0, v1, v2, v3);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 447) v0 ^= entropy;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 448) } while (unlikely(!v0 || !v1 || !v2 || !v3));
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 449)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 450) WRITE_ONCE(state->v0, v0);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 451) WRITE_ONCE(state->v1, v1);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 452) WRITE_ONCE(state->v2, v2);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 453) WRITE_ONCE(state->v3, v3);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 454) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 455) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 456) EXPORT_SYMBOL(prandom_seed);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 457)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 458) /*
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 459) * Generate some initially weak seeding values to allow
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 460) * the prandom_u32() engine to be started.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 461) */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 462) static int __init prandom_init_early(void)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 463) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 464) int i;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 465) unsigned long v0, v1, v2, v3;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 466)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 467) if (!arch_get_random_long(&v0))
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 468) v0 = jiffies;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 469) if (!arch_get_random_long(&v1))
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 470) v1 = random_get_entropy();
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 471) v2 = v0 ^ PRND_K0;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 472) v3 = v1 ^ PRND_K1;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 473)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 474) for_each_possible_cpu(i) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 475) struct siprand_state *state;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 476)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 477) v3 ^= i;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 478) PRND_SIPROUND(v0, v1, v2, v3);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 479) PRND_SIPROUND(v0, v1, v2, v3);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 480) v0 ^= i;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 481)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 482) state = per_cpu_ptr(&net_rand_state, i);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 483) state->v0 = v0; state->v1 = v1;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 484) state->v2 = v2; state->v3 = v3;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 485) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 486)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 487) return 0;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 488) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 489) core_initcall(prandom_init_early);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 490)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 491)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 492) /* Stronger reseeding when available, and periodically thereafter. */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 493) static void prandom_reseed(struct timer_list *unused);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 494)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 495) static DEFINE_TIMER(seed_timer, prandom_reseed);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 496)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 497) static void prandom_reseed(struct timer_list *unused)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 498) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 499) unsigned long expires;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 500) int i;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 501)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 502) /*
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 503) * Reinitialize each CPU's PRNG with 128 bits of key.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 504) * No locking on the CPUs, but then somewhat random results are,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 505) * well, expected.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 506) */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 507) for_each_possible_cpu(i) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 508) struct siprand_state *state;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 509) unsigned long v0 = get_random_long(), v2 = v0 ^ PRND_K0;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 510) unsigned long v1 = get_random_long(), v3 = v1 ^ PRND_K1;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 511) #if BITS_PER_LONG == 32
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 512) int j;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 513)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 514) /*
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 515) * On 32-bit machines, hash in two extra words to
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 516) * approximate 128-bit key length. Not that the hash
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 517) * has that much security, but this prevents a trivial
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 518) * 64-bit brute force.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 519) */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 520) for (j = 0; j < 2; j++) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 521) unsigned long m = get_random_long();
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 522)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 523) v3 ^= m;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 524) PRND_SIPROUND(v0, v1, v2, v3);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 525) PRND_SIPROUND(v0, v1, v2, v3);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 526) v0 ^= m;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 527) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 528) #endif
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 529) /*
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 530) * Probably impossible in practice, but there is a
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 531) * theoretical risk that a race between this reseeding
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 532) * and the target CPU writing its state back could
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 533) * create the all-zero SipHash fixed point.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 534) *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 535) * To ensure that never happens, ensure the state
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 536) * we write contains no zero words.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 537) */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 538) state = per_cpu_ptr(&net_rand_state, i);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 539) WRITE_ONCE(state->v0, v0 ? v0 : -1ul);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 540) WRITE_ONCE(state->v1, v1 ? v1 : -1ul);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 541) WRITE_ONCE(state->v2, v2 ? v2 : -1ul);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 542) WRITE_ONCE(state->v3, v3 ? v3 : -1ul);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 543) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 544)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 545) /* reseed every ~60 seconds, in [40 .. 80) interval with slack */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 546) expires = round_jiffies(jiffies + 40 * HZ + prandom_u32_max(40 * HZ));
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 547) mod_timer(&seed_timer, expires);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 548) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 549)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 550) /*
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 551) * The random ready callback can be called from almost any interrupt.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 552) * To avoid worrying about whether it's safe to delay that interrupt
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 553) * long enough to seed all CPUs, just schedule an immediate timer event.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 554) */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 555) static void prandom_timer_start(struct random_ready_callback *unused)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 556) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 557) mod_timer(&seed_timer, jiffies);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 558) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 559)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 560) #ifdef CONFIG_RANDOM32_SELFTEST
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 561) /* Principle: True 32-bit random numbers will all have 16 differing bits on
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 562) * average. For each 32-bit number, there are 601M numbers differing by 16
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 563) * bits, and 89% of the numbers differ by at least 12 bits. Note that more
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 564) * than 16 differing bits also implies a correlation with inverted bits. Thus
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 565) * we take 1024 random numbers and compare each of them to the other ones,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 566) * counting the deviation of correlated bits to 16. Constants report 32,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 567) * counters 32-log2(TEST_SIZE), and pure randoms, around 6 or lower. With the
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 568) * u32 total, TEST_SIZE may be as large as 4096 samples.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 569) */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 570) #define TEST_SIZE 1024
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 571) static int __init prandom32_state_selftest(void)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 572) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 573) unsigned int x, y, bits, samples;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 574) u32 xor, flip;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 575) u32 total;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 576) u32 *data;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 577)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 578) data = kmalloc(sizeof(*data) * TEST_SIZE, GFP_KERNEL);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 579) if (!data)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 580) return 0;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 581)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 582) for (samples = 0; samples < TEST_SIZE; samples++)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 583) data[samples] = prandom_u32();
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 584)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 585) flip = total = 0;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 586) for (x = 0; x < samples; x++) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 587) for (y = 0; y < samples; y++) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 588) if (x == y)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 589) continue;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 590) xor = data[x] ^ data[y];
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 591) flip |= xor;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 592) bits = hweight32(xor);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 593) total += (bits - 16) * (bits - 16);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 594) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 595) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 596)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 597) /* We'll return the average deviation as 2*sqrt(corr/samples), which
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 598) * is also sqrt(4*corr/samples) which provides a better resolution.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 599) */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 600) bits = int_sqrt(total / (samples * (samples - 1)) * 4);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 601) if (bits > 6)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 602) pr_warn("prandom32: self test failed (at least %u bits"
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 603) " correlated, fixed_mask=%#x fixed_value=%#x\n",
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 604) bits, ~flip, data[0] & ~flip);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 605) else
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 606) pr_info("prandom32: self test passed (less than %u bits"
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 607) " correlated)\n",
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 608) bits+1);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 609) kfree(data);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 610) return 0;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 611) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 612) core_initcall(prandom32_state_selftest);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 613) #endif /* CONFIG_RANDOM32_SELFTEST */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 614)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 615) /*
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 616) * Start periodic full reseeding as soon as strong
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 617) * random numbers are available.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 618) */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 619) static int __init prandom_init_late(void)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 620) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 621) static struct random_ready_callback random_ready = {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 622) .func = prandom_timer_start
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 623) };
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 624) int ret = add_random_ready_callback(&random_ready);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 625)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 626) if (ret == -EALREADY) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 627) prandom_timer_start(&random_ready);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 628) ret = 0;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 629) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 630) return ret;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 631) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 632) late_initcall(prandom_init_late);
Orange Pi5 kernel
Deprecated Linux kernel 5.10.110 for OrangePi 5/5B/5+ boards
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