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 typedef __uint128_t u128; 14 15 void poly1305_core_setkey(struct poly1305_core_key *key, const u8 raw_key[16]) 16 { 17 u64 t0, t1; 18 19 /* r &= 0xffffffc0ffffffc0ffffffc0fffffff */ 20 t0 = get_unaligned_le64(&raw_key[0]); 21 t1 = get_unaligned_le64(&raw_key[8]); 22 23 key->key.r64[0] = t0 & 0xffc0fffffffULL; 24 key->key.r64[1] = ((t0 >> 44) | (t1 << 20)) & 0xfffffc0ffffULL; 25 key->key.r64[2] = ((t1 >> 24)) & 0x00ffffffc0fULL; 26 27 /* s = 20*r */ 28 key->precomputed_s.r64[0] = key->key.r64[1] * 20; 29 key->precomputed_s.r64[1] = key->key.r64[2] * 20; 30 } 31 EXPORT_SYMBOL(poly1305_core_setkey); 32 33 void poly1305_core_blocks(struct poly1305_state *state, 34 const struct poly1305_core_key *key, const void *src, 35 unsigned int nblocks, u32 hibit) 36 { 37 const u8 *input = src; 38 u64 hibit64; 39 u64 r0, r1, r2; 40 u64 s1, s2; 41 u64 h0, h1, h2; 42 u64 c; 43 u128 d0, d1, d2, d; 44 45 if (!nblocks) 46 return; 47 48 hibit64 = ((u64)hibit) << 40; 49 50 r0 = key->key.r64[0]; 51 r1 = key->key.r64[1]; 52 r2 = key->key.r64[2]; 53 54 h0 = state->h64[0]; 55 h1 = state->h64[1]; 56 h2 = state->h64[2]; 57 58 s1 = key->precomputed_s.r64[0]; 59 s2 = key->precomputed_s.r64[1]; 60 61 do { 62 u64 t0, t1; 63 64 /* h += m[i] */ 65 t0 = get_unaligned_le64(&input[0]); 66 t1 = get_unaligned_le64(&input[8]); 67 68 h0 += t0 & 0xfffffffffffULL; 69 h1 += ((t0 >> 44) | (t1 << 20)) & 0xfffffffffffULL; 70 h2 += (((t1 >> 24)) & 0x3ffffffffffULL) | hibit64; 71 72 /* h *= r */ 73 d0 = (u128)h0 * r0; 74 d = (u128)h1 * s2; 75 d0 += d; 76 d = (u128)h2 * s1; 77 d0 += d; 78 d1 = (u128)h0 * r1; 79 d = (u128)h1 * r0; 80 d1 += d; 81 d = (u128)h2 * s2; 82 d1 += d; 83 d2 = (u128)h0 * r2; 84 d = (u128)h1 * r1; 85 d2 += d; 86 d = (u128)h2 * r0; 87 d2 += d; 88 89 /* (partial) h %= p */ 90 c = (u64)(d0 >> 44); 91 h0 = (u64)d0 & 0xfffffffffffULL; 92 d1 += c; 93 c = (u64)(d1 >> 44); 94 h1 = (u64)d1 & 0xfffffffffffULL; 95 d2 += c; 96 c = (u64)(d2 >> 42); 97 h2 = (u64)d2 & 0x3ffffffffffULL; 98 h0 += c * 5; 99 c = h0 >> 44; 100 h0 = h0 & 0xfffffffffffULL; 101 h1 += c; 102 103 input += POLY1305_BLOCK_SIZE; 104 } while (--nblocks); 105 106 state->h64[0] = h0; 107 state->h64[1] = h1; 108 state->h64[2] = h2; 109 } 110 EXPORT_SYMBOL(poly1305_core_blocks); 111 112 void poly1305_core_emit(const struct poly1305_state *state, const u32 nonce[4], 113 void *dst) 114 { 115 u8 *mac = dst; 116 u64 h0, h1, h2, c; 117 u64 g0, g1, g2; 118 u64 t0, t1; 119 120 /* fully carry h */ 121 h0 = state->h64[0]; 122 h1 = state->h64[1]; 123 h2 = state->h64[2]; 124 125 c = h1 >> 44; 126 h1 &= 0xfffffffffffULL; 127 h2 += c; 128 c = h2 >> 42; 129 h2 &= 0x3ffffffffffULL; 130 h0 += c * 5; 131 c = h0 >> 44; 132 h0 &= 0xfffffffffffULL; 133 h1 += c; 134 c = h1 >> 44; 135 h1 &= 0xfffffffffffULL; 136 h2 += c; 137 c = h2 >> 42; 138 h2 &= 0x3ffffffffffULL; 139 h0 += c * 5; 140 c = h0 >> 44; 141 h0 &= 0xfffffffffffULL; 142 h1 += c; 143 144 /* compute h + -p */ 145 g0 = h0 + 5; 146 c = g0 >> 44; 147 g0 &= 0xfffffffffffULL; 148 g1 = h1 + c; 149 c = g1 >> 44; 150 g1 &= 0xfffffffffffULL; 151 g2 = h2 + c - (1ULL << 42); 152 153 /* select h if h < p, or h + -p if h >= p */ 154 c = (g2 >> ((sizeof(u64) * 8) - 1)) - 1; 155 g0 &= c; 156 g1 &= c; 157 g2 &= c; 158 c = ~c; 159 h0 = (h0 & c) | g0; 160 h1 = (h1 & c) | g1; 161 h2 = (h2 & c) | g2; 162 163 if (likely(nonce)) { 164 /* h = (h + nonce) */ 165 t0 = ((u64)nonce[1] << 32) | nonce[0]; 166 t1 = ((u64)nonce[3] << 32) | nonce[2]; 167 168 h0 += t0 & 0xfffffffffffULL; 169 c = h0 >> 44; 170 h0 &= 0xfffffffffffULL; 171 h1 += (((t0 >> 44) | (t1 << 20)) & 0xfffffffffffULL) + c; 172 c = h1 >> 44; 173 h1 &= 0xfffffffffffULL; 174 h2 += (((t1 >> 24)) & 0x3ffffffffffULL) + c; 175 h2 &= 0x3ffffffffffULL; 176 } 177 178 /* mac = h % (2^128) */ 179 h0 = h0 | (h1 << 44); 180 h1 = (h1 >> 20) | (h2 << 24); 181 182 put_unaligned_le64(h0, &mac[0]); 183 put_unaligned_le64(h1, &mac[8]); 184 } 185 EXPORT_SYMBOL(poly1305_core_emit); 186