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