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1// SPDX-License-Identifier: GPL-2.0 OR MIT2/*3 * Copyright (C) 2015-2019 Jason A. Donenfeld <Jason@zx2c4.com>. All Rights Reserved.4 *5 * This is based in part on Andrew Moon's poly1305-donna, which is in the6 * public domain.7 */8 9#include <linux/kernel.h>10#include <linux/unaligned.h>11#include <crypto/internal/poly1305.h>12 13void poly1305_core_setkey(struct poly1305_core_key *key,14 const u8 raw_key[POLY1305_BLOCK_SIZE])15{16 /* r &= 0xffffffc0ffffffc0ffffffc0fffffff */17 key->key.r[0] = (get_unaligned_le32(&raw_key[0])) & 0x3ffffff;18 key->key.r[1] = (get_unaligned_le32(&raw_key[3]) >> 2) & 0x3ffff03;19 key->key.r[2] = (get_unaligned_le32(&raw_key[6]) >> 4) & 0x3ffc0ff;20 key->key.r[3] = (get_unaligned_le32(&raw_key[9]) >> 6) & 0x3f03fff;21 key->key.r[4] = (get_unaligned_le32(&raw_key[12]) >> 8) & 0x00fffff;22 23 /* s = 5*r */24 key->precomputed_s.r[0] = key->key.r[1] * 5;25 key->precomputed_s.r[1] = key->key.r[2] * 5;26 key->precomputed_s.r[2] = key->key.r[3] * 5;27 key->precomputed_s.r[3] = key->key.r[4] * 5;28}29EXPORT_SYMBOL(poly1305_core_setkey);30 31void poly1305_core_blocks(struct poly1305_state *state,32 const struct poly1305_core_key *key, const void *src,33 unsigned int nblocks, u32 hibit)34{35 const u8 *input = src;36 u32 r0, r1, r2, r3, r4;37 u32 s1, s2, s3, s4;38 u32 h0, h1, h2, h3, h4;39 u64 d0, d1, d2, d3, d4;40 u32 c;41 42 if (!nblocks)43 return;44 45 hibit <<= 24;46 47 r0 = key->key.r[0];48 r1 = key->key.r[1];49 r2 = key->key.r[2];50 r3 = key->key.r[3];51 r4 = key->key.r[4];52 53 s1 = key->precomputed_s.r[0];54 s2 = key->precomputed_s.r[1];55 s3 = key->precomputed_s.r[2];56 s4 = key->precomputed_s.r[3];57 58 h0 = state->h[0];59 h1 = state->h[1];60 h2 = state->h[2];61 h3 = state->h[3];62 h4 = state->h[4];63 64 do {65 /* h += m[i] */66 h0 += (get_unaligned_le32(&input[0])) & 0x3ffffff;67 h1 += (get_unaligned_le32(&input[3]) >> 2) & 0x3ffffff;68 h2 += (get_unaligned_le32(&input[6]) >> 4) & 0x3ffffff;69 h3 += (get_unaligned_le32(&input[9]) >> 6) & 0x3ffffff;70 h4 += (get_unaligned_le32(&input[12]) >> 8) | hibit;71 72 /* h *= r */73 d0 = ((u64)h0 * r0) + ((u64)h1 * s4) +74 ((u64)h2 * s3) + ((u64)h3 * s2) +75 ((u64)h4 * s1);76 d1 = ((u64)h0 * r1) + ((u64)h1 * r0) +77 ((u64)h2 * s4) + ((u64)h3 * s3) +78 ((u64)h4 * s2);79 d2 = ((u64)h0 * r2) + ((u64)h1 * r1) +80 ((u64)h2 * r0) + ((u64)h3 * s4) +81 ((u64)h4 * s3);82 d3 = ((u64)h0 * r3) + ((u64)h1 * r2) +83 ((u64)h2 * r1) + ((u64)h3 * r0) +84 ((u64)h4 * s4);85 d4 = ((u64)h0 * r4) + ((u64)h1 * r3) +86 ((u64)h2 * r2) + ((u64)h3 * r1) +87 ((u64)h4 * r0);88 89 /* (partial) h %= p */90 c = (u32)(d0 >> 26);91 h0 = (u32)d0 & 0x3ffffff;92 d1 += c;93 c = (u32)(d1 >> 26);94 h1 = (u32)d1 & 0x3ffffff;95 d2 += c;96 c = (u32)(d2 >> 26);97 h2 = (u32)d2 & 0x3ffffff;98 d3 += c;99 c = (u32)(d3 >> 26);100 h3 = (u32)d3 & 0x3ffffff;101 d4 += c;102 c = (u32)(d4 >> 26);103 h4 = (u32)d4 & 0x3ffffff;104 h0 += c * 5;105 c = (h0 >> 26);106 h0 = h0 & 0x3ffffff;107 h1 += c;108 109 input += POLY1305_BLOCK_SIZE;110 } while (--nblocks);111 112 state->h[0] = h0;113 state->h[1] = h1;114 state->h[2] = h2;115 state->h[3] = h3;116 state->h[4] = h4;117}118EXPORT_SYMBOL(poly1305_core_blocks);119 120void poly1305_core_emit(const struct poly1305_state *state, const u32 nonce[4],121 void *dst)122{123 u8 *mac = dst;124 u32 h0, h1, h2, h3, h4, c;125 u32 g0, g1, g2, g3, g4;126 u64 f;127 u32 mask;128 129 /* fully carry h */130 h0 = state->h[0];131 h1 = state->h[1];132 h2 = state->h[2];133 h3 = state->h[3];134 h4 = state->h[4];135 136 c = h1 >> 26;137 h1 = h1 & 0x3ffffff;138 h2 += c;139 c = h2 >> 26;140 h2 = h2 & 0x3ffffff;141 h3 += c;142 c = h3 >> 26;143 h3 = h3 & 0x3ffffff;144 h4 += c;145 c = h4 >> 26;146 h4 = h4 & 0x3ffffff;147 h0 += c * 5;148 c = h0 >> 26;149 h0 = h0 & 0x3ffffff;150 h1 += c;151 152 /* compute h + -p */153 g0 = h0 + 5;154 c = g0 >> 26;155 g0 &= 0x3ffffff;156 g1 = h1 + c;157 c = g1 >> 26;158 g1 &= 0x3ffffff;159 g2 = h2 + c;160 c = g2 >> 26;161 g2 &= 0x3ffffff;162 g3 = h3 + c;163 c = g3 >> 26;164 g3 &= 0x3ffffff;165 g4 = h4 + c - (1UL << 26);166 167 /* select h if h < p, or h + -p if h >= p */168 mask = (g4 >> ((sizeof(u32) * 8) - 1)) - 1;169 g0 &= mask;170 g1 &= mask;171 g2 &= mask;172 g3 &= mask;173 g4 &= mask;174 mask = ~mask;175 176 h0 = (h0 & mask) | g0;177 h1 = (h1 & mask) | g1;178 h2 = (h2 & mask) | g2;179 h3 = (h3 & mask) | g3;180 h4 = (h4 & mask) | g4;181 182 /* h = h % (2^128) */183 h0 = ((h0) | (h1 << 26)) & 0xffffffff;184 h1 = ((h1 >> 6) | (h2 << 20)) & 0xffffffff;185 h2 = ((h2 >> 12) | (h3 << 14)) & 0xffffffff;186 h3 = ((h3 >> 18) | (h4 << 8)) & 0xffffffff;187 188 if (likely(nonce)) {189 /* mac = (h + nonce) % (2^128) */190 f = (u64)h0 + nonce[0];191 h0 = (u32)f;192 f = (u64)h1 + nonce[1] + (f >> 32);193 h1 = (u32)f;194 f = (u64)h2 + nonce[2] + (f >> 32);195 h2 = (u32)f;196 f = (u64)h3 + nonce[3] + (f >> 32);197 h3 = (u32)f;198 }199 200 put_unaligned_le32(h0, &mac[0]);201 put_unaligned_le32(h1, &mac[4]);202 put_unaligned_le32(h2, &mac[8]);203 put_unaligned_le32(h3, &mac[12]);204}205EXPORT_SYMBOL(poly1305_core_emit);206