diff options
Diffstat (limited to 'stdlib/chacha20.c')
| -rw-r--r-- | stdlib/chacha20.c | 191 |
1 files changed, 0 insertions, 191 deletions
diff --git a/stdlib/chacha20.c b/stdlib/chacha20.c deleted file mode 100644 index 2745a81315..0000000000 --- a/stdlib/chacha20.c +++ /dev/null @@ -1,191 +0,0 @@ -/* Generic ChaCha20 implementation (used on arc4random). - Copyright (C) 2022 Free Software Foundation, Inc. - This file is part of the GNU C Library. - - The GNU C Library is free software; you can redistribute it and/or - modify it under the terms of the GNU Lesser General Public - License as published by the Free Software Foundation; either - version 2.1 of the License, or (at your option) any later version. - - The GNU C Library is distributed in the hope that it will be useful, - but WITHOUT ANY WARRANTY; without even the implied warranty of - MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU - Lesser General Public License for more details. - - You should have received a copy of the GNU Lesser General Public - License along with the GNU C Library; if not, see - <https://www.gnu.org/licenses/>. */ - -#include <array_length.h> -#include <endian.h> -#include <stddef.h> -#include <stdint.h> -#include <string.h> - -/* 32-bit stream position, then 96-bit nonce. */ -#define CHACHA20_IV_SIZE 16 -#define CHACHA20_KEY_SIZE 32 - -#define CHACHA20_STATE_LEN 16 - -/* The ChaCha20 implementation is based on RFC8439 [1], omitting the final - XOR of the keystream with the plaintext because the plaintext is a - stream of zeros. */ - -enum chacha20_constants -{ - CHACHA20_CONSTANT_EXPA = 0x61707865U, - CHACHA20_CONSTANT_ND_3 = 0x3320646eU, - CHACHA20_CONSTANT_2_BY = 0x79622d32U, - CHACHA20_CONSTANT_TE_K = 0x6b206574U -}; - -static inline uint32_t -read_unaligned_32 (const uint8_t *p) -{ - uint32_t r; - memcpy (&r, p, sizeof (r)); - return r; -} - -static inline void -write_unaligned_32 (uint8_t *p, uint32_t v) -{ - memcpy (p, &v, sizeof (v)); -} - -#if __BYTE_ORDER == __BIG_ENDIAN -# define read_unaligned_le32(p) __builtin_bswap32 (read_unaligned_32 (p)) -# define set_state(v) __builtin_bswap32 ((v)) -#else -# define read_unaligned_le32(p) read_unaligned_32 ((p)) -# define set_state(v) (v) -#endif - -static inline void -chacha20_init (uint32_t *state, const uint8_t *key, const uint8_t *iv) -{ - state[0] = CHACHA20_CONSTANT_EXPA; - state[1] = CHACHA20_CONSTANT_ND_3; - state[2] = CHACHA20_CONSTANT_2_BY; - state[3] = CHACHA20_CONSTANT_TE_K; - - state[4] = read_unaligned_le32 (key + 0 * sizeof (uint32_t)); - state[5] = read_unaligned_le32 (key + 1 * sizeof (uint32_t)); - state[6] = read_unaligned_le32 (key + 2 * sizeof (uint32_t)); - state[7] = read_unaligned_le32 (key + 3 * sizeof (uint32_t)); - state[8] = read_unaligned_le32 (key + 4 * sizeof (uint32_t)); - state[9] = read_unaligned_le32 (key + 5 * sizeof (uint32_t)); - state[10] = read_unaligned_le32 (key + 6 * sizeof (uint32_t)); - state[11] = read_unaligned_le32 (key + 7 * sizeof (uint32_t)); - - state[12] = read_unaligned_le32 (iv + 0 * sizeof (uint32_t)); - state[13] = read_unaligned_le32 (iv + 1 * sizeof (uint32_t)); - state[14] = read_unaligned_le32 (iv + 2 * sizeof (uint32_t)); - state[15] = read_unaligned_le32 (iv + 3 * sizeof (uint32_t)); -} - -static inline uint32_t -rotl32 (unsigned int shift, uint32_t word) -{ - return (word << (shift & 31)) | (word >> ((-shift) & 31)); -} - -static void -state_final (const uint8_t *src, uint8_t *dst, uint32_t v) -{ -#ifdef CHACHA20_XOR_FINAL - v ^= read_unaligned_32 (src); -#endif - write_unaligned_32 (dst, v); -} - -static inline void -chacha20_block (uint32_t *state, uint8_t *dst, const uint8_t *src) -{ - uint32_t x0, x1, x2, x3, x4, x5, x6, x7; - uint32_t x8, x9, x10, x11, x12, x13, x14, x15; - - x0 = state[0]; - x1 = state[1]; - x2 = state[2]; - x3 = state[3]; - x4 = state[4]; - x5 = state[5]; - x6 = state[6]; - x7 = state[7]; - x8 = state[8]; - x9 = state[9]; - x10 = state[10]; - x11 = state[11]; - x12 = state[12]; - x13 = state[13]; - x14 = state[14]; - x15 = state[15]; - - for (int i = 0; i < 20; i += 2) - { -#define QROUND(_x0, _x1, _x2, _x3) \ - do { \ - _x0 = _x0 + _x1; _x3 = rotl32 (16, (_x0 ^ _x3)); \ - _x2 = _x2 + _x3; _x1 = rotl32 (12, (_x1 ^ _x2)); \ - _x0 = _x0 + _x1; _x3 = rotl32 (8, (_x0 ^ _x3)); \ - _x2 = _x2 + _x3; _x1 = rotl32 (7, (_x1 ^ _x2)); \ - } while(0) - - QROUND (x0, x4, x8, x12); - QROUND (x1, x5, x9, x13); - QROUND (x2, x6, x10, x14); - QROUND (x3, x7, x11, x15); - - QROUND (x0, x5, x10, x15); - QROUND (x1, x6, x11, x12); - QROUND (x2, x7, x8, x13); - QROUND (x3, x4, x9, x14); - } - - state_final (&src[0], &dst[0], set_state (x0 + state[0])); - state_final (&src[4], &dst[4], set_state (x1 + state[1])); - state_final (&src[8], &dst[8], set_state (x2 + state[2])); - state_final (&src[12], &dst[12], set_state (x3 + state[3])); - state_final (&src[16], &dst[16], set_state (x4 + state[4])); - state_final (&src[20], &dst[20], set_state (x5 + state[5])); - state_final (&src[24], &dst[24], set_state (x6 + state[6])); - state_final (&src[28], &dst[28], set_state (x7 + state[7])); - state_final (&src[32], &dst[32], set_state (x8 + state[8])); - state_final (&src[36], &dst[36], set_state (x9 + state[9])); - state_final (&src[40], &dst[40], set_state (x10 + state[10])); - state_final (&src[44], &dst[44], set_state (x11 + state[11])); - state_final (&src[48], &dst[48], set_state (x12 + state[12])); - state_final (&src[52], &dst[52], set_state (x13 + state[13])); - state_final (&src[56], &dst[56], set_state (x14 + state[14])); - state_final (&src[60], &dst[60], set_state (x15 + state[15])); - - state[12]++; -} - -static void -__attribute_maybe_unused__ -chacha20_crypt_generic (uint32_t *state, uint8_t *dst, const uint8_t *src, - size_t bytes) -{ - while (bytes >= CHACHA20_BLOCK_SIZE) - { - chacha20_block (state, dst, src); - - bytes -= CHACHA20_BLOCK_SIZE; - dst += CHACHA20_BLOCK_SIZE; - src += CHACHA20_BLOCK_SIZE; - } - - if (__glibc_unlikely (bytes != 0)) - { - uint8_t stream[CHACHA20_BLOCK_SIZE]; - chacha20_block (state, stream, src); - memcpy (dst, stream, bytes); - explicit_bzero (stream, sizeof stream); - } -} - -/* Get the architecture optimized version. */ -#include <chacha20_arch.h> |