1 /* $OpenBSD: chacha.c,v 1.10 2023/07/05 16:17:20 beck Exp $ */ 2 /* 3 * Copyright (c) 2014 Joel Sing <jsing@openbsd.org> 4 * 5 * Permission to use, copy, modify, and distribute this software for any 6 * purpose with or without fee is hereby granted, provided that the above 7 * copyright notice and this permission notice appear in all copies. 8 * 9 * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES 10 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF 11 * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR 12 * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES 13 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN 14 * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF 15 * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE. 16 */ 17 18 #include <stdint.h> 19 20 #include <openssl/chacha.h> 21 22 #include "chacha-merged.c" 23 24 void 25 ChaCha_set_key(ChaCha_ctx *ctx, const unsigned char *key, uint32_t keybits) 26 { 27 chacha_keysetup((chacha_ctx *)ctx, key, keybits); 28 ctx->unused = 0; 29 } 30 LCRYPTO_ALIAS(ChaCha_set_key); 31 32 void 33 ChaCha_set_iv(ChaCha_ctx *ctx, const unsigned char *iv, 34 const unsigned char *counter) 35 { 36 chacha_ivsetup((chacha_ctx *)ctx, iv, counter); 37 ctx->unused = 0; 38 } 39 LCRYPTO_ALIAS(ChaCha_set_iv); 40 41 void 42 ChaCha(ChaCha_ctx *ctx, unsigned char *out, const unsigned char *in, size_t len) 43 { 44 unsigned char *k; 45 uint64_t n; 46 int i, l; 47 48 /* Consume remaining keystream, if any exists. */ 49 if (ctx->unused > 0) { 50 k = ctx->ks + 64 - ctx->unused; 51 l = (len > ctx->unused) ? ctx->unused : len; 52 for (i = 0; i < l; i++) 53 *(out++) = *(in++) ^ *(k++); 54 ctx->unused -= l; 55 len -= l; 56 } 57 58 while (len > 0) { 59 if ((n = len) > UINT32_MAX) 60 n = UINT32_MAX; 61 62 chacha_encrypt_bytes((chacha_ctx *)ctx, in, out, (uint32_t)n); 63 64 in += n; 65 out += n; 66 len -= n; 67 } 68 } 69 LCRYPTO_ALIAS(ChaCha); 70 71 void 72 CRYPTO_chacha_20(unsigned char *out, const unsigned char *in, size_t len, 73 const unsigned char key[32], const unsigned char iv[8], uint64_t counter) 74 { 75 struct chacha_ctx ctx; 76 uint64_t n; 77 78 /* 79 * chacha_ivsetup expects the counter to be in u8. Rather than 80 * converting size_t to u8 and then back again, pass a counter of 81 * NULL and manually assign it afterwards. 82 */ 83 chacha_keysetup(&ctx, key, 256); 84 chacha_ivsetup(&ctx, iv, NULL); 85 if (counter != 0) { 86 ctx.input[12] = (uint32_t)counter; 87 ctx.input[13] = (uint32_t)(counter >> 32); 88 } 89 90 while (len > 0) { 91 if ((n = len) > UINT32_MAX) 92 n = UINT32_MAX; 93 94 chacha_encrypt_bytes(&ctx, in, out, (uint32_t)n); 95 96 in += n; 97 out += n; 98 len -= n; 99 } 100 } 101 LCRYPTO_ALIAS(CRYPTO_chacha_20); 102 103 void 104 CRYPTO_xchacha_20(unsigned char *out, const unsigned char *in, size_t len, 105 const unsigned char key[32], const unsigned char iv[24]) 106 { 107 uint8_t subkey[32]; 108 109 CRYPTO_hchacha_20(subkey, key, iv); 110 CRYPTO_chacha_20(out, in, len, subkey, iv + 16, 0); 111 } 112 LCRYPTO_ALIAS(CRYPTO_xchacha_20); 113