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 <linux/kernel.h> 10 #include <asm/unaligned.h> 11 #include <crypto/internal/poly1305.h> 12 13 void 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 } 29 EXPORT_SYMBOL(poly1305_core_setkey); 30 31 void 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 } 118 EXPORT_SYMBOL(poly1305_core_blocks); 119 120 void 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 } 205 EXPORT_SYMBOL(poly1305_core_emit); 206