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 /* Copyright (c) 2023, 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. */ #include #include #include #include "../internal.h" #include "./internal.h" // keccak_f implements the Keccak-1600 permutation as described at // https://keccak.team/keccak_specs_summary.html. Each lane is represented as a // 64-bit value and the 5×5 lanes are stored as an array in row-major order. static void keccak_f(uint64_t state[25]) { static const int kNumRounds = 24; for (int round = 0; round < kNumRounds; round++) { // θ step uint64_t c[5]; for (int x = 0; x < 5; x++) { c[x] = state[x] ^ state[x + 5] ^ state[x + 10] ^ state[x + 15] ^ state[x + 20]; } for (int x = 0; x < 5; x++) { const uint64_t d = c[(x + 4) % 5] ^ CRYPTO_rotl_u64(c[(x + 1) % 5], 1); for (int y = 0; y < 5; y++) { state[y * 5 + x] ^= d; } } // ρ and π steps. // // These steps involve a mapping of the state matrix. Each input point, // (x,y), is rotated and written to the point (y, 2x + 3y). In the Keccak // pseudo-code a separate array is used because an in-place operation would // overwrite some values that are subsequently needed. However, the mapping // forms a trail through 24 of the 25 values so we can do it in place with // only a single temporary variable. // // Start with (1, 0). The value here will be mapped and end up at (0, 2). // That value will end up at (2, 1), then (1, 2), and so on. After 24 // steps, 24 of the 25 values have been hit (as this mapping is injective) // and the sequence will repeat. All that remains is to handle the element // at (0, 0), but the rotation for that element is zero, and it goes to (0, // 0), so we can ignore it. uint64_t prev_value = state[1]; #define PI_RHO_STEP(index, rotation) \ do { \ const uint64_t value = CRYPTO_rotl_u64(prev_value, rotation); \ prev_value = state[index]; \ state[index] = value; \ } while (0) PI_RHO_STEP(10, 1); PI_RHO_STEP(7, 3); PI_RHO_STEP(11, 6); PI_RHO_STEP(17, 10); PI_RHO_STEP(18, 15); PI_RHO_STEP(3, 21); PI_RHO_STEP(5, 28); PI_RHO_STEP(16, 36); PI_RHO_STEP(8, 45); PI_RHO_STEP(21, 55); PI_RHO_STEP(24, 2); PI_RHO_STEP(4, 14); PI_RHO_STEP(15, 27); PI_RHO_STEP(23, 41); PI_RHO_STEP(19, 56); PI_RHO_STEP(13, 8); PI_RHO_STEP(12, 25); PI_RHO_STEP(2, 43); PI_RHO_STEP(20, 62); PI_RHO_STEP(14, 18); PI_RHO_STEP(22, 39); PI_RHO_STEP(9, 61); PI_RHO_STEP(6, 20); PI_RHO_STEP(1, 44); #undef PI_RHO_STEP // χ step for (int y = 0; y < 5; y++) { const int row_index = 5 * y; const uint64_t orig_x0 = state[row_index]; const uint64_t orig_x1 = state[row_index + 1]; state[row_index] ^= ~orig_x1 & state[row_index + 2]; state[row_index + 1] ^= ~state[row_index + 2] & state[row_index + 3]; state[row_index + 2] ^= ~state[row_index + 3] & state[row_index + 4]; state[row_index + 3] ^= ~state[row_index + 4] & orig_x0; state[row_index + 4] ^= ~orig_x0 & orig_x1; } // ι step // // From https://keccak.team/files/Keccak-reference-3.0.pdf, section // 1.2, the round constants are based on the output of a LFSR. Thus, as // suggested in the appendix of of // https://keccak.team/keccak_specs_summary.html, the values are // simply encoded here. static const uint64_t kRoundConstants[24] = { 0x0000000000000001, 0x0000000000008082, 0x800000000000808a, 0x8000000080008000, 0x000000000000808b, 0x0000000080000001, 0x8000000080008081, 0x8000000000008009, 0x000000000000008a, 0x0000000000000088, 0x0000000080008009, 0x000000008000000a, 0x000000008000808b, 0x800000000000008b, 0x8000000000008089, 0x8000000000008003, 0x8000000000008002, 0x8000000000000080, 0x000000000000800a, 0x800000008000000a, 0x8000000080008081, 0x8000000000008080, 0x0000000080000001, 0x8000000080008008, }; state[0] ^= kRoundConstants[round]; } } static void keccak_init(struct BORINGSSL_keccak_st *ctx, size_t *out_required_out_len, enum boringssl_keccak_config_t config) { size_t capacity_bytes; switch (config) { case boringssl_sha3_256: capacity_bytes = 512 / 8; *out_required_out_len = 32; break; case boringssl_sha3_512: capacity_bytes = 1024 / 8; *out_required_out_len = 64; break; case boringssl_shake128: capacity_bytes = 256 / 8; *out_required_out_len = 0; break; case boringssl_shake256: capacity_bytes = 512 / 8; *out_required_out_len = 0; break; default: abort(); } OPENSSL_memset(ctx, 0, sizeof(*ctx)); ctx->config = config; ctx->phase = boringssl_keccak_phase_absorb; ctx->rate_bytes = 200 - capacity_bytes; assert(ctx->rate_bytes % 8 == 0); } void BORINGSSL_keccak(uint8_t *out, size_t out_len, const uint8_t *in, size_t in_len, enum boringssl_keccak_config_t config) { struct BORINGSSL_keccak_st ctx; size_t required_out_len; keccak_init(&ctx, &required_out_len, config); if (required_out_len != 0 && out_len != required_out_len) { abort(); } BORINGSSL_keccak_absorb(&ctx, in, in_len); BORINGSSL_keccak_squeeze(&ctx, out, out_len); } void BORINGSSL_keccak_init(struct BORINGSSL_keccak_st *ctx, enum boringssl_keccak_config_t config) { size_t required_out_len; keccak_init(ctx, &required_out_len, config); if (required_out_len != 0) { abort(); } } void BORINGSSL_keccak_absorb(struct BORINGSSL_keccak_st *ctx, const uint8_t *in, size_t in_len) { if (ctx->phase == boringssl_keccak_phase_squeeze) { // It's illegal to call absorb() again after calling squeeze(). abort(); } const size_t rate_words = ctx->rate_bytes / 8; // XOR the input. Accessing |ctx->state| as a |uint8_t*| is allowed by strict // aliasing because we require |uint8_t| to be a character type. uint8_t *state_bytes = (uint8_t *)ctx->state; // Absorb partial block. if (ctx->absorb_offset != 0) { assert(ctx->absorb_offset < ctx->rate_bytes); size_t first_block_len = ctx->rate_bytes - ctx->absorb_offset; for (size_t i = 0; i < first_block_len && i < in_len; i++) { state_bytes[ctx->absorb_offset + i] ^= in[i]; } // This input didn't fill the block. if (first_block_len > in_len) { ctx->absorb_offset += in_len; return; } keccak_f(ctx->state); in += first_block_len; in_len -= first_block_len; } // Absorb full blocks. while (in_len >= ctx->rate_bytes) { for (size_t i = 0; i < rate_words; i++) { ctx->state[i] ^= CRYPTO_load_u64_le(in + 8 * i); } keccak_f(ctx->state); in += ctx->rate_bytes; in_len -= ctx->rate_bytes; } // Absorb partial block. assert(in_len < ctx->rate_bytes); for (size_t i = 0; i < in_len; i++) { state_bytes[i] ^= in[i]; } ctx->absorb_offset = in_len; } static void keccak_finalize(struct BORINGSSL_keccak_st *ctx) { uint8_t terminator; switch (ctx->config) { case boringssl_sha3_256: case boringssl_sha3_512: terminator = 0x06; break; case boringssl_shake128: case boringssl_shake256: terminator = 0x1f; break; default: abort(); } // XOR the terminator. Accessing |ctx->state| as a |uint8_t*| is allowed by // strict aliasing because we require |uint8_t| to be a character type. uint8_t *state_bytes = (uint8_t *)ctx->state; state_bytes[ctx->absorb_offset] ^= terminator; state_bytes[ctx->rate_bytes - 1] ^= 0x80; keccak_f(ctx->state); } void BORINGSSL_keccak_squeeze(struct BORINGSSL_keccak_st *ctx, uint8_t *out, size_t out_len) { if (ctx->phase == boringssl_keccak_phase_absorb) { keccak_finalize(ctx); ctx->phase = boringssl_keccak_phase_squeeze; } // Accessing |ctx->state| as a |uint8_t*| is allowed by strict aliasing // because we require |uint8_t| to be a character type. const uint8_t *state_bytes = (const uint8_t *)ctx->state; while (out_len) { if (ctx->squeeze_offset == ctx->rate_bytes) { keccak_f(ctx->state); ctx->squeeze_offset = 0; } size_t remaining = ctx->rate_bytes - ctx->squeeze_offset; size_t todo = out_len; if (todo > remaining) { todo = remaining; } OPENSSL_memcpy(out, &state_bytes[ctx->squeeze_offset], todo); out += todo; out_len -= todo; ctx->squeeze_offset += todo; } }