237 lines
6.8 KiB
C
237 lines
6.8 KiB
C
// Copyright (c) 2014, Google Inc.
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// SPDX-License-Identifier: ISC
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// Adapted from the public domain, estream code by D. Bernstein.
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#include <openssl/chacha.h>
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#include <assert.h>
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#include <string.h>
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#include "../internal.h"
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#include "internal.h"
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// sigma contains the ChaCha constants, which happen to be an ASCII string.
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// "expand 32-byte k"
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static const uint32_t sigma_words[4] = {
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0x61707865, // 'e' 0x65, 'x' 0x78, 'p' 0x70, 'a' 0x61,
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0x3320646e, // 'n' 0x6E, 'd' 0x64, ' ' 0x20, '3' 0x33,
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0x79622d32, // '2' 0x32, '-' 0x2D, 'b' 0x62, 'y' 0x79,
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0x6b206574 // 't' 0x74, 'e' 0x65, ' ' 0x20, 'k' 0x6B
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};
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// QUARTERROUND updates a, b, c, d with a ChaCha "quarter" round.
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#define QUARTERROUND(a, b, c, d) \
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x[a] += x[b]; \
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x[d] = CRYPTO_rotl_u32(x[d] ^ x[a], 16); \
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x[c] += x[d]; \
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x[b] = CRYPTO_rotl_u32(x[b] ^ x[c], 12); \
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x[a] += x[b]; \
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x[d] = CRYPTO_rotl_u32(x[d] ^ x[a], 8); \
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x[c] += x[d]; \
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x[b] = CRYPTO_rotl_u32(x[b] ^ x[c], 7);
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void CRYPTO_hchacha20(uint8_t out[32], const uint8_t key[32],
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const uint8_t nonce[16]) {
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uint32_t x[16];
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OPENSSL_memcpy(x, sigma_words, sizeof(sigma_words));
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#ifdef OPENSSL_BIG_ENDIAN
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for(size_t i = 4; i < 12; i++) {
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x[i] = CRYPTO_load_u32_le(key + (i-4) * sizeof(uint32_t));
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}
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for(size_t i = 12; i < 16; i++) {
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x[i] = CRYPTO_load_u32_le(nonce + (i-12) * sizeof(uint32_t));
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}
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#else
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OPENSSL_memcpy(&x[4], key, 32);
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OPENSSL_memcpy(&x[12], nonce, 16);
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#endif
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for (size_t i = 0; i < 20; i += 2) {
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QUARTERROUND(0, 4, 8, 12)
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QUARTERROUND(1, 5, 9, 13)
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QUARTERROUND(2, 6, 10, 14)
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QUARTERROUND(3, 7, 11, 15)
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QUARTERROUND(0, 5, 10, 15)
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QUARTERROUND(1, 6, 11, 12)
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QUARTERROUND(2, 7, 8, 13)
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QUARTERROUND(3, 4, 9, 14)
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}
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#ifdef OPENSSL_BIG_ENDIAN
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for(size_t i = 0; i < 4; i++) {
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CRYPTO_store_u32_le(out + i * sizeof(uint32_t), x[i]);
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}
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for(size_t i = 12; i < 16; i++) {
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CRYPTO_store_u32_le(out + (i-8) * sizeof(uint32_t), x[i]);
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}
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#else
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OPENSSL_memcpy(out, &x[0], sizeof(uint32_t) * 4);
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OPENSSL_memcpy(&out[16], &x[12], sizeof(uint32_t) * 4);
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#endif
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}
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#if defined(CHACHA20_ASM_NOHW)
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static void ChaCha20_ctr32(uint8_t *out, const uint8_t *in, size_t in_len,
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const uint32_t key[8], const uint32_t counter[4]) {
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#if defined(CHACHA20_ASM_NEON)
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if (ChaCha20_ctr32_neon_capable(in_len)) {
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ChaCha20_ctr32_neon(out, in, in_len, key, counter);
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return;
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}
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#endif
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#if defined(CHACHA20_ASM_AVX2) && !defined(MY_ASSEMBLER_IS_TOO_OLD_FOR_512AVX)
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if (ChaCha20_ctr32_avx2_capable(in_len)) {
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ChaCha20_ctr32_avx2(out, in, in_len, key, counter);
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return;
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}
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#endif
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#if defined(CHACHA20_ASM_SSSE3_4X)
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if (ChaCha20_ctr32_ssse3_4x_capable(in_len)) {
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ChaCha20_ctr32_ssse3_4x(out, in, in_len, key, counter);
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return;
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}
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#endif
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#if defined(CHACHA20_ASM_SSSE3)
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if (ChaCha20_ctr32_ssse3_capable(in_len)) {
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ChaCha20_ctr32_ssse3(out, in, in_len, key, counter);
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return;
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}
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#endif
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if (in_len > 0) {
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ChaCha20_ctr32_nohw(out, in, in_len, key, counter);
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}
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}
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#endif
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#if defined(CHACHA20_ASM_NOHW)
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void CRYPTO_chacha_20(uint8_t *out, const uint8_t *in, size_t in_len,
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const uint8_t key[32], const uint8_t nonce[12],
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uint32_t counter) {
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assert(!buffers_alias(out, in_len, in, in_len) || in == out);
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uint32_t counter_nonce[4];
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counter_nonce[0] = counter;
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counter_nonce[1] = CRYPTO_load_u32_le(nonce + 0);
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counter_nonce[2] = CRYPTO_load_u32_le(nonce + 4);
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counter_nonce[3] = CRYPTO_load_u32_le(nonce + 8);
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const uint32_t *key_ptr = (const uint32_t *)key;
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#if !defined(OPENSSL_X86) && !defined(OPENSSL_X86_64)
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// The assembly expects the key to be four-byte aligned.
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uint32_t key_u32[8];
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if ((((uintptr_t)key) & 3) != 0) {
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key_u32[0] = CRYPTO_load_u32_le(key + 0);
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key_u32[1] = CRYPTO_load_u32_le(key + 4);
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key_u32[2] = CRYPTO_load_u32_le(key + 8);
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key_u32[3] = CRYPTO_load_u32_le(key + 12);
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key_u32[4] = CRYPTO_load_u32_le(key + 16);
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key_u32[5] = CRYPTO_load_u32_le(key + 20);
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key_u32[6] = CRYPTO_load_u32_le(key + 24);
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key_u32[7] = CRYPTO_load_u32_le(key + 28);
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key_ptr = key_u32;
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}
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#endif
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while (in_len > 0) {
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// The assembly functions do not have defined overflow behavior. While
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// overflow is almost always a bug in the caller, we prefer our functions to
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// behave the same across platforms, so divide into multiple calls to avoid
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// this case.
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uint64_t todo = 64 * ((UINT64_C(1) << 32) - counter_nonce[0]);
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if (todo > in_len) {
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todo = in_len;
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}
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ChaCha20_ctr32(out, in, (size_t)todo, key_ptr, counter_nonce);
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in += todo;
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out += todo;
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in_len -= todo;
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// We're either done and will next break out of the loop, or we stopped at
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// the wraparound point and the counter should continue at zero.
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counter_nonce[0] = 0;
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}
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}
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#else
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// chacha_core performs 20 rounds of ChaCha on the input words in
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// |input| and writes the 64 output bytes to |output|.
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static void chacha_core(uint8_t output[64], const uint32_t input[16]) {
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uint32_t x[16];
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int i;
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OPENSSL_memcpy(x, input, sizeof(uint32_t) * 16);
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for (i = 20; i > 0; i -= 2) {
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QUARTERROUND(0, 4, 8, 12)
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QUARTERROUND(1, 5, 9, 13)
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QUARTERROUND(2, 6, 10, 14)
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QUARTERROUND(3, 7, 11, 15)
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QUARTERROUND(0, 5, 10, 15)
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QUARTERROUND(1, 6, 11, 12)
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QUARTERROUND(2, 7, 8, 13)
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QUARTERROUND(3, 4, 9, 14)
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}
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for (i = 0; i < 16; ++i) {
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x[i] += input[i];
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}
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for (i = 0; i < 16; ++i) {
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CRYPTO_store_u32_le(output + 4 * i, x[i]);
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}
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}
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void CRYPTO_chacha_20(uint8_t *out, const uint8_t *in, size_t in_len,
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const uint8_t key[32], const uint8_t nonce[12],
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uint32_t counter) {
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assert(!buffers_alias(out, in_len, in, in_len) || in == out);
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uint32_t input[16];
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uint8_t buf[64];
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size_t todo, i;
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input[0] = sigma_words[0];
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input[1] = sigma_words[1];
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input[2] = sigma_words[2];
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input[3] = sigma_words[3];
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input[4] = CRYPTO_load_u32_le(key + 0);
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input[5] = CRYPTO_load_u32_le(key + 4);
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input[6] = CRYPTO_load_u32_le(key + 8);
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input[7] = CRYPTO_load_u32_le(key + 12);
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input[8] = CRYPTO_load_u32_le(key + 16);
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input[9] = CRYPTO_load_u32_le(key + 20);
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input[10] = CRYPTO_load_u32_le(key + 24);
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input[11] = CRYPTO_load_u32_le(key + 28);
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input[12] = counter;
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input[13] = CRYPTO_load_u32_le(nonce + 0);
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input[14] = CRYPTO_load_u32_le(nonce + 4);
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input[15] = CRYPTO_load_u32_le(nonce + 8);
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while (in_len > 0) {
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todo = sizeof(buf);
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if (in_len < todo) {
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todo = in_len;
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}
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chacha_core(buf, input);
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for (i = 0; i < todo; i++) {
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out[i] = in[i] ^ buf[i];
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}
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out += todo;
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in += todo;
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in_len -= todo;
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input[12]++;
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}
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}
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#endif
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