1 // SPDX-License-Identifier: GPL-2.0 OR MIT 2 /* 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 the 6 * public domain. 7 */ 8 9 #include <crypto/internal/poly1305.h> 10 #include <linux/export.h> 11 #include <linux/kernel.h> 12 #include <linux/unaligned.h> 13 14 void poly1305_core_setkey(struct poly1305_core_key *key, 15 const u8 raw_key[POLY1305_BLOCK_SIZE]) 16 { 17 /* r &= 0xffffffc0ffffffc0ffffffc0fffffff */ 18 key->key.r[0] = (get_unaligned_le32(&raw_key[0])) & 0x3ffffff; 19 key->key.r[1] = (get_unaligned_le32(&raw_key[3]) >> 2) & 0x3ffff03; 20 key->key.r[2] = (get_unaligned_le32(&raw_key[6]) >> 4) & 0x3ffc0ff; 21 key->key.r[3] = (get_unaligned_le32(&raw_key[9]) >> 6) & 0x3f03fff; 22 key->key.r[4] = (get_unaligned_le32(&raw_key[12]) >> 8) & 0x00fffff; 23 24 /* s = 5*r */ 25 key->precomputed_s.r[0] = key->key.r[1] * 5; 26 key->precomputed_s.r[1] = key->key.r[2] * 5; 27 key->precomputed_s.r[2] = key->key.r[3] * 5; 28 key->precomputed_s.r[3] = key->key.r[4] * 5; 29 } 30 EXPORT_SYMBOL(poly1305_core_setkey); 31 32 void poly1305_core_blocks(struct poly1305_state *state, 33 const struct poly1305_core_key *key, const void *src, 34 unsigned int nblocks, u32 hibit) 35 { 36 const u8 *input = src; 37 u32 r0, r1, r2, r3, r4; 38 u32 s1, s2, s3, s4; 39 u32 h0, h1, h2, h3, h4; 40 u64 d0, d1, d2, d3, d4; 41 u32 c; 42 43 if (!nblocks) 44 return; 45 46 hibit <<= 24; 47 48 r0 = key->key.r[0]; 49 r1 = key->key.r[1]; 50 r2 = key->key.r[2]; 51 r3 = key->key.r[3]; 52 r4 = key->key.r[4]; 53 54 s1 = key->precomputed_s.r[0]; 55 s2 = key->precomputed_s.r[1]; 56 s3 = key->precomputed_s.r[2]; 57 s4 = key->precomputed_s.r[3]; 58 59 h0 = state->h[0]; 60 h1 = state->h[1]; 61 h2 = state->h[2]; 62 h3 = state->h[3]; 63 h4 = state->h[4]; 64 65 do { 66 /* h += m[i] */ 67 h0 += (get_unaligned_le32(&input[0])) & 0x3ffffff; 68 h1 += (get_unaligned_le32(&input[3]) >> 2) & 0x3ffffff; 69 h2 += (get_unaligned_le32(&input[6]) >> 4) & 0x3ffffff; 70 h3 += (get_unaligned_le32(&input[9]) >> 6) & 0x3ffffff; 71 h4 += (get_unaligned_le32(&input[12]) >> 8) | hibit; 72 73 /* h *= r */ 74 d0 = ((u64)h0 * r0) + ((u64)h1 * s4) + 75 ((u64)h2 * s3) + ((u64)h3 * s2) + 76 ((u64)h4 * s1); 77 d1 = ((u64)h0 * r1) + ((u64)h1 * r0) + 78 ((u64)h2 * s4) + ((u64)h3 * s3) + 79 ((u64)h4 * s2); 80 d2 = ((u64)h0 * r2) + ((u64)h1 * r1) + 81 ((u64)h2 * r0) + ((u64)h3 * s4) + 82 ((u64)h4 * s3); 83 d3 = ((u64)h0 * r3) + ((u64)h1 * r2) + 84 ((u64)h2 * r1) + ((u64)h3 * r0) + 85 ((u64)h4 * s4); 86 d4 = ((u64)h0 * r4) + ((u64)h1 * r3) + 87 ((u64)h2 * r2) + ((u64)h3 * r1) + 88 ((u64)h4 * r0); 89 90 /* (partial) h %= p */ 91 c = (u32)(d0 >> 26); 92 h0 = (u32)d0 & 0x3ffffff; 93 d1 += c; 94 c = (u32)(d1 >> 26); 95 h1 = (u32)d1 & 0x3ffffff; 96 d2 += c; 97 c = (u32)(d2 >> 26); 98 h2 = (u32)d2 & 0x3ffffff; 99 d3 += c; 100 c = (u32)(d3 >> 26); 101 h3 = (u32)d3 & 0x3ffffff; 102 d4 += c; 103 c = (u32)(d4 >> 26); 104 h4 = (u32)d4 & 0x3ffffff; 105 h0 += c * 5; 106 c = (h0 >> 26); 107 h0 = h0 & 0x3ffffff; 108 h1 += c; 109 110 input += POLY1305_BLOCK_SIZE; 111 } while (--nblocks); 112 113 state->h[0] = h0; 114 state->h[1] = h1; 115 state->h[2] = h2; 116 state->h[3] = h3; 117 state->h[4] = h4; 118 } 119 EXPORT_SYMBOL(poly1305_core_blocks); 120 121 void poly1305_core_emit(const struct poly1305_state *state, const u32 nonce[4], 122 void *dst) 123 { 124 u8 *mac = dst; 125 u32 h0, h1, h2, h3, h4, c; 126 u32 g0, g1, g2, g3, g4; 127 u64 f; 128 u32 mask; 129 130 /* fully carry h */ 131 h0 = state->h[0]; 132 h1 = state->h[1]; 133 h2 = state->h[2]; 134 h3 = state->h[3]; 135 h4 = state->h[4]; 136 137 c = h1 >> 26; 138 h1 = h1 & 0x3ffffff; 139 h2 += c; 140 c = h2 >> 26; 141 h2 = h2 & 0x3ffffff; 142 h3 += c; 143 c = h3 >> 26; 144 h3 = h3 & 0x3ffffff; 145 h4 += c; 146 c = h4 >> 26; 147 h4 = h4 & 0x3ffffff; 148 h0 += c * 5; 149 c = h0 >> 26; 150 h0 = h0 & 0x3ffffff; 151 h1 += c; 152 153 /* compute h + -p */ 154 g0 = h0 + 5; 155 c = g0 >> 26; 156 g0 &= 0x3ffffff; 157 g1 = h1 + c; 158 c = g1 >> 26; 159 g1 &= 0x3ffffff; 160 g2 = h2 + c; 161 c = g2 >> 26; 162 g2 &= 0x3ffffff; 163 g3 = h3 + c; 164 c = g3 >> 26; 165 g3 &= 0x3ffffff; 166 g4 = h4 + c - (1UL << 26); 167 168 /* select h if h < p, or h + -p if h >= p */ 169 mask = (g4 >> ((sizeof(u32) * 8) - 1)) - 1; 170 g0 &= mask; 171 g1 &= mask; 172 g2 &= mask; 173 g3 &= mask; 174 g4 &= mask; 175 mask = ~mask; 176 177 h0 = (h0 & mask) | g0; 178 h1 = (h1 & mask) | g1; 179 h2 = (h2 & mask) | g2; 180 h3 = (h3 & mask) | g3; 181 h4 = (h4 & mask) | g4; 182 183 /* h = h % (2^128) */ 184 h0 = ((h0) | (h1 << 26)) & 0xffffffff; 185 h1 = ((h1 >> 6) | (h2 << 20)) & 0xffffffff; 186 h2 = ((h2 >> 12) | (h3 << 14)) & 0xffffffff; 187 h3 = ((h3 >> 18) | (h4 << 8)) & 0xffffffff; 188 189 if (likely(nonce)) { 190 /* mac = (h + nonce) % (2^128) */ 191 f = (u64)h0 + nonce[0]; 192 h0 = (u32)f; 193 f = (u64)h1 + nonce[1] + (f >> 32); 194 h1 = (u32)f; 195 f = (u64)h2 + nonce[2] + (f >> 32); 196 h2 = (u32)f; 197 f = (u64)h3 + nonce[3] + (f >> 32); 198 h3 = (u32)f; 199 } 200 201 put_unaligned_le32(h0, &mac[0]); 202 put_unaligned_le32(h1, &mac[4]); 203 put_unaligned_le32(h2, &mac[8]); 204 put_unaligned_le32(h3, &mac[12]); 205 } 206 EXPORT_SYMBOL(poly1305_core_emit); 207