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/* Copyright (c) 2014, Google Inc.
*
* Permission to use, copy, modify, and/or distribute this software for any
* purpose with or without fee is hereby granted, provided that the above
* copyright notice and this permission notice appear in all copies.
*
* THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
* WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
* MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY
* SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
* WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION
* OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN
* CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE. */
/* This implementation of poly1305 is by Andrew Moon
* (https://github.com/floodyberry/poly1305-donna) and released as public
* domain. */
#include <openssl/poly1305.h>
#include <string.h>
#include <openssl/cpu.h>
#include "internal.h"
#if defined(OPENSSL_WINDOWS) || !defined(OPENSSL_X86_64)
/* We can assume little-endian. */
static uint32_t U8TO32_LE(const uint8_t *m) {
uint32_t r;
memcpy(&r, m, sizeof(r));
return r;
}
static void U32TO8_LE(uint8_t *m, uint32_t v) { memcpy(m, &v, sizeof(v)); }
static uint64_t mul32x32_64(uint32_t a, uint32_t b) { return (uint64_t)a * b; }
struct poly1305_state_st {
uint32_t r0, r1, r2, r3, r4;
uint32_t s1, s2, s3, s4;
uint32_t h0, h1, h2, h3, h4;
uint8_t buf[16];
unsigned int buf_used;
uint8_t key[16];
};
static inline struct poly1305_state_st *poly1305_aligned_state(
poly1305_state *state) {
return (struct poly1305_state_st *)(((uintptr_t)state + 63) & ~63);
}
/* poly1305_blocks updates |state| given some amount of input data. This
* function may only be called with a |len| that is not a multiple of 16 at the
* end of the data. Otherwise the input must be buffered into 16 byte blocks. */
static void poly1305_update(struct poly1305_state_st *state, const uint8_t *in,
size_t len) {
uint32_t t0, t1, t2, t3;
uint64_t t[5];
uint32_t b;
uint64_t c;
size_t j;
uint8_t mp[16];
if (len < 16) {
goto poly1305_donna_atmost15bytes;
}
poly1305_donna_16bytes:
t0 = U8TO32_LE(in);
t1 = U8TO32_LE(in + 4);
t2 = U8TO32_LE(in + 8);
t3 = U8TO32_LE(in + 12);
in += 16;
len -= 16;
state->h0 += t0 & 0x3ffffff;
state->h1 += ((((uint64_t)t1 << 32) | t0) >> 26) & 0x3ffffff;
state->h2 += ((((uint64_t)t2 << 32) | t1) >> 20) & 0x3ffffff;
state->h3 += ((((uint64_t)t3 << 32) | t2) >> 14) & 0x3ffffff;
state->h4 += (t3 >> 8) | (1 << 24);
poly1305_donna_mul:
t[0] = mul32x32_64(state->h0, state->r0) + mul32x32_64(state->h1, state->s4) +
mul32x32_64(state->h2, state->s3) + mul32x32_64(state->h3, state->s2) +
mul32x32_64(state->h4, state->s1);
t[1] = mul32x32_64(state->h0, state->r1) + mul32x32_64(state->h1, state->r0) +
mul32x32_64(state->h2, state->s4) + mul32x32_64(state->h3, state->s3) +
mul32x32_64(state->h4, state->s2);
t[2] = mul32x32_64(state->h0, state->r2) + mul32x32_64(state->h1, state->r1) +
mul32x32_64(state->h2, state->r0) + mul32x32_64(state->h3, state->s4) +
mul32x32_64(state->h4, state->s3);
t[3] = mul32x32_64(state->h0, state->r3) + mul32x32_64(state->h1, state->r2) +
mul32x32_64(state->h2, state->r1) + mul32x32_64(state->h3, state->r0) +
mul32x32_64(state->h4, state->s4);
t[4] = mul32x32_64(state->h0, state->r4) + mul32x32_64(state->h1, state->r3) +
mul32x32_64(state->h2, state->r2) + mul32x32_64(state->h3, state->r1) +
mul32x32_64(state->h4, state->r0);
state->h0 = (uint32_t)t[0] & 0x3ffffff;
c = (t[0] >> 26);
t[1] += c;
state->h1 = (uint32_t)t[1] & 0x3ffffff;
b = (uint32_t)(t[1] >> 26);
t[2] += b;
state->h2 = (uint32_t)t[2] & 0x3ffffff;
b = (uint32_t)(t[2] >> 26);
t[3] += b;
state->h3 = (uint32_t)t[3] & 0x3ffffff;
b = (uint32_t)(t[3] >> 26);
t[4] += b;
state->h4 = (uint32_t)t[4] & 0x3ffffff;
b = (uint32_t)(t[4] >> 26);
state->h0 += b * 5;
if (len >= 16) {
goto poly1305_donna_16bytes;
}
/* final bytes */
poly1305_donna_atmost15bytes:
if (!len) {
return;
}
for (j = 0; j < len; j++) {
mp[j] = in[j];
}
mp[j++] = 1;
for (; j < 16; j++) {
mp[j] = 0;
}
len = 0;
t0 = U8TO32_LE(mp + 0);
t1 = U8TO32_LE(mp + 4);
t2 = U8TO32_LE(mp + 8);
t3 = U8TO32_LE(mp + 12);
state->h0 += t0 & 0x3ffffff;
state->h1 += ((((uint64_t)t1 << 32) | t0) >> 26) & 0x3ffffff;
state->h2 += ((((uint64_t)t2 << 32) | t1) >> 20) & 0x3ffffff;
state->h3 += ((((uint64_t)t3 << 32) | t2) >> 14) & 0x3ffffff;
state->h4 += (t3 >> 8);
goto poly1305_donna_mul;
}
void CRYPTO_poly1305_init(poly1305_state *statep, const uint8_t key[32]) {
struct poly1305_state_st *state = poly1305_aligned_state(statep);
uint32_t t0, t1, t2, t3;
#if defined(OPENSSL_ARM) && !defined(OPENSSL_NO_ASM)
if (CRYPTO_is_NEON_capable()) {
CRYPTO_poly1305_init_neon(statep, key);
return;
}
#endif
t0 = U8TO32_LE(key + 0);
t1 = U8TO32_LE(key + 4);
t2 = U8TO32_LE(key + 8);
t3 = U8TO32_LE(key + 12);
/* precompute multipliers */
state->r0 = t0 & 0x3ffffff;
t0 >>= 26;
t0 |= t1 << 6;
state->r1 = t0 & 0x3ffff03;
t1 >>= 20;
t1 |= t2 << 12;
state->r2 = t1 & 0x3ffc0ff;
t2 >>= 14;
t2 |= t3 << 18;
state->r3 = t2 & 0x3f03fff;
t3 >>= 8;
state->r4 = t3 & 0x00fffff;
state->s1 = state->r1 * 5;
state->s2 = state->r2 * 5;
state->s3 = state->r3 * 5;
state->s4 = state->r4 * 5;
/* init state */
state->h0 = 0;
state->h1 = 0;
state->h2 = 0;
state->h3 = 0;
state->h4 = 0;
state->buf_used = 0;
memcpy(state->key, key + 16, sizeof(state->key));
}
void CRYPTO_poly1305_update(poly1305_state *statep, const uint8_t *in,
size_t in_len) {
unsigned int i;
struct poly1305_state_st *state = poly1305_aligned_state(statep);
#if defined(OPENSSL_ARM) && !defined(OPENSSL_NO_ASM)
if (CRYPTO_is_NEON_capable()) {
CRYPTO_poly1305_update_neon(statep, in, in_len);
return;
}
#endif
if (state->buf_used) {
unsigned todo = 16 - state->buf_used;
if (todo > in_len) {
todo = (unsigned)in_len;
}
for (i = 0; i < todo; i++) {
state->buf[state->buf_used + i] = in[i];
}
state->buf_used += todo;
in_len -= todo;
in += todo;
if (state->buf_used == 16) {
poly1305_update(state, state->buf, 16);
state->buf_used = 0;
}
}
if (in_len >= 16) {
size_t todo = in_len & ~0xf;
poly1305_update(state, in, todo);
in += todo;
in_len &= 0xf;
}
if (in_len) {
for (i = 0; i < in_len; i++) {
state->buf[i] = in[i];
}
state->buf_used = (unsigned)in_len;
}
}
void CRYPTO_poly1305_finish(poly1305_state *statep, uint8_t mac[16]) {
struct poly1305_state_st *state = poly1305_aligned_state(statep);
uint64_t f0, f1, f2, f3;
uint32_t g0, g1, g2, g3, g4;
uint32_t b, nb;
#if defined(OPENSSL_ARM) && !defined(OPENSSL_NO_ASM)
if (CRYPTO_is_NEON_capable()) {
CRYPTO_poly1305_finish_neon(statep, mac);
return;
}
#endif
if (state->buf_used) {
poly1305_update(state, state->buf, state->buf_used);
}
b = state->h0 >> 26;
state->h0 = state->h0 & 0x3ffffff;
state->h1 += b;
b = state->h1 >> 26;
state->h1 = state->h1 & 0x3ffffff;
state->h2 += b;
b = state->h2 >> 26;
state->h2 = state->h2 & 0x3ffffff;
state->h3 += b;
b = state->h3 >> 26;
state->h3 = state->h3 & 0x3ffffff;
state->h4 += b;
b = state->h4 >> 26;
state->h4 = state->h4 & 0x3ffffff;
state->h0 += b * 5;
g0 = state->h0 + 5;
b = g0 >> 26;
g0 &= 0x3ffffff;
g1 = state->h1 + b;
b = g1 >> 26;
g1 &= 0x3ffffff;
g2 = state->h2 + b;
b = g2 >> 26;
g2 &= 0x3ffffff;
g3 = state->h3 + b;
b = g3 >> 26;
g3 &= 0x3ffffff;
g4 = state->h4 + b - (1 << 26);
b = (g4 >> 31) - 1;
nb = ~b;
state->h0 = (state->h0 & nb) | (g0 & b);
state->h1 = (state->h1 & nb) | (g1 & b);
state->h2 = (state->h2 & nb) | (g2 & b);
state->h3 = (state->h3 & nb) | (g3 & b);
state->h4 = (state->h4 & nb) | (g4 & b);
f0 = ((state->h0) | (state->h1 << 26)) + (uint64_t)U8TO32_LE(&state->key[0]);
f1 = ((state->h1 >> 6) | (state->h2 << 20)) +
(uint64_t)U8TO32_LE(&state->key[4]);
f2 = ((state->h2 >> 12) | (state->h3 << 14)) +
(uint64_t)U8TO32_LE(&state->key[8]);
f3 = ((state->h3 >> 18) | (state->h4 << 8)) +
(uint64_t)U8TO32_LE(&state->key[12]);
U32TO8_LE(&mac[0], f0);
f1 += (f0 >> 32);
U32TO8_LE(&mac[4], f1);
f2 += (f1 >> 32);
U32TO8_LE(&mac[8], f2);
f3 += (f2 >> 32);
U32TO8_LE(&mac[12], f3);
}
#endif /* OPENSSL_WINDOWS || !OPENSSL_X86_64 */