1 /* 2 * Copyright 2019-2023 The OpenSSL Project Authors. All Rights Reserved. 3 * 4 * Licensed under the Apache License 2.0 (the "License"). You may not use 5 * this file except in compliance with the License. You can obtain a copy 6 * in the file LICENSE in the source distribution or at 7 * https://www.openssl.org/source/license.html 8 */ 9 10 /* chacha20_poly1305 cipher implementation */ 11 12 #include "internal/endian.h" 13 #include "cipher_chacha20_poly1305.h" 14 15 static int chacha_poly1305_tls_init(PROV_CIPHER_CTX *bctx, 16 unsigned char *aad, size_t alen) 17 { 18 unsigned int len; 19 PROV_CHACHA20_POLY1305_CTX *ctx = (PROV_CHACHA20_POLY1305_CTX *)bctx; 20 21 if (alen != EVP_AEAD_TLS1_AAD_LEN) 22 return 0; 23 24 memcpy(ctx->tls_aad, aad, EVP_AEAD_TLS1_AAD_LEN); 25 len = aad[EVP_AEAD_TLS1_AAD_LEN - 2] << 8 | aad[EVP_AEAD_TLS1_AAD_LEN - 1]; 26 aad = ctx->tls_aad; 27 if (!bctx->enc) { 28 if (len < POLY1305_BLOCK_SIZE) 29 return 0; 30 len -= POLY1305_BLOCK_SIZE; /* discount attached tag */ 31 aad[EVP_AEAD_TLS1_AAD_LEN - 2] = (unsigned char)(len >> 8); 32 aad[EVP_AEAD_TLS1_AAD_LEN - 1] = (unsigned char)len; 33 } 34 ctx->tls_payload_length = len; 35 36 /* merge record sequence number as per RFC7905 */ 37 ctx->chacha.counter[1] = ctx->nonce[0]; 38 ctx->chacha.counter[2] = ctx->nonce[1] ^ CHACHA_U8TOU32(aad); 39 ctx->chacha.counter[3] = ctx->nonce[2] ^ CHACHA_U8TOU32(aad+4); 40 ctx->mac_inited = 0; 41 42 return POLY1305_BLOCK_SIZE; /* tag length */ 43 } 44 45 static int chacha_poly1305_tls_iv_set_fixed(PROV_CIPHER_CTX *bctx, 46 unsigned char *fixed, size_t flen) 47 { 48 PROV_CHACHA20_POLY1305_CTX *ctx = (PROV_CHACHA20_POLY1305_CTX *)bctx; 49 50 if (flen != CHACHA20_POLY1305_IVLEN) 51 return 0; 52 ctx->nonce[0] = ctx->chacha.counter[1] = CHACHA_U8TOU32(fixed); 53 ctx->nonce[1] = ctx->chacha.counter[2] = CHACHA_U8TOU32(fixed + 4); 54 ctx->nonce[2] = ctx->chacha.counter[3] = CHACHA_U8TOU32(fixed + 8); 55 return 1; 56 } 57 58 static int chacha20_poly1305_initkey(PROV_CIPHER_CTX *bctx, 59 const unsigned char *key, size_t keylen) 60 { 61 PROV_CHACHA20_POLY1305_CTX *ctx = (PROV_CHACHA20_POLY1305_CTX *)bctx; 62 63 ctx->len.aad = 0; 64 ctx->len.text = 0; 65 ctx->aad = 0; 66 ctx->mac_inited = 0; 67 ctx->tls_payload_length = NO_TLS_PAYLOAD_LENGTH; 68 69 if (bctx->enc) 70 return ossl_chacha20_einit(&ctx->chacha, key, keylen, NULL, 0, NULL); 71 else 72 return ossl_chacha20_dinit(&ctx->chacha, key, keylen, NULL, 0, NULL); 73 } 74 75 static int chacha20_poly1305_initiv(PROV_CIPHER_CTX *bctx) 76 { 77 PROV_CHACHA20_POLY1305_CTX *ctx = (PROV_CHACHA20_POLY1305_CTX *)bctx; 78 unsigned char tempiv[CHACHA_CTR_SIZE] = { 0 }; 79 int ret = 1; 80 size_t noncelen = CHACHA20_POLY1305_IVLEN; 81 82 ctx->len.aad = 0; 83 ctx->len.text = 0; 84 ctx->aad = 0; 85 ctx->mac_inited = 0; 86 ctx->tls_payload_length = NO_TLS_PAYLOAD_LENGTH; 87 88 /* pad on the left */ 89 memcpy(tempiv + CHACHA_CTR_SIZE - noncelen, bctx->oiv, 90 noncelen); 91 92 if (bctx->enc) 93 ret = ossl_chacha20_einit(&ctx->chacha, NULL, 0, 94 tempiv, sizeof(tempiv), NULL); 95 else 96 ret = ossl_chacha20_dinit(&ctx->chacha, NULL, 0, 97 tempiv, sizeof(tempiv), NULL); 98 ctx->nonce[0] = ctx->chacha.counter[1]; 99 ctx->nonce[1] = ctx->chacha.counter[2]; 100 ctx->nonce[2] = ctx->chacha.counter[3]; 101 bctx->iv_set = 1; 102 return ret; 103 } 104 105 #if !defined(OPENSSL_SMALL_FOOTPRINT) 106 107 # if defined(POLY1305_ASM) && (defined(__x86_64) || defined(__x86_64__) \ 108 || defined(_M_AMD64) || defined(_M_X64)) 109 # define XOR128_HELPERS 110 void *xor128_encrypt_n_pad(void *out, const void *inp, void *otp, size_t len); 111 void *xor128_decrypt_n_pad(void *out, const void *inp, void *otp, size_t len); 112 static const unsigned char zero[4 * CHACHA_BLK_SIZE] = { 0 }; 113 # else 114 static const unsigned char zero[2 * CHACHA_BLK_SIZE] = { 0 }; 115 # endif 116 117 static int chacha20_poly1305_tls_cipher(PROV_CIPHER_CTX *bctx, 118 unsigned char *out, 119 size_t *out_padlen, 120 const unsigned char *in, size_t len) 121 { 122 PROV_CHACHA20_POLY1305_CTX *ctx = (PROV_CHACHA20_POLY1305_CTX *)bctx; 123 POLY1305 *poly = &ctx->poly1305; 124 size_t tail, tohash_len, buf_len, plen = ctx->tls_payload_length; 125 unsigned char *buf, *tohash, *ctr, storage[sizeof(zero) + 32]; 126 127 DECLARE_IS_ENDIAN; 128 129 buf = storage + ((0 - (size_t)storage) & 15); /* align */ 130 ctr = buf + CHACHA_BLK_SIZE; 131 tohash = buf + CHACHA_BLK_SIZE - POLY1305_BLOCK_SIZE; 132 133 # ifdef XOR128_HELPERS 134 if (plen <= 3 * CHACHA_BLK_SIZE) { 135 ctx->chacha.counter[0] = 0; 136 buf_len = (plen + 2 * CHACHA_BLK_SIZE - 1) & (0 - CHACHA_BLK_SIZE); 137 ChaCha20_ctr32(buf, zero, buf_len, ctx->chacha.key.d, ctx->chacha.counter); 138 Poly1305_Init(poly, buf); 139 ctx->chacha.partial_len = 0; 140 memcpy(tohash, ctx->tls_aad, POLY1305_BLOCK_SIZE); 141 tohash_len = POLY1305_BLOCK_SIZE; 142 ctx->len.aad = EVP_AEAD_TLS1_AAD_LEN; 143 ctx->len.text = plen; 144 145 if (plen) { 146 if (bctx->enc) 147 ctr = xor128_encrypt_n_pad(out, in, ctr, plen); 148 else 149 ctr = xor128_decrypt_n_pad(out, in, ctr, plen); 150 151 in += plen; 152 out += plen; 153 tohash_len = (size_t)(ctr - tohash); 154 } 155 } 156 # else 157 if (plen <= CHACHA_BLK_SIZE) { 158 size_t i; 159 160 ctx->chacha.counter[0] = 0; 161 ChaCha20_ctr32(buf, zero, (buf_len = 2 * CHACHA_BLK_SIZE), 162 ctx->chacha.key.d, ctx->chacha.counter); 163 Poly1305_Init(poly, buf); 164 ctx->chacha.partial_len = 0; 165 memcpy(tohash, ctx->tls_aad, POLY1305_BLOCK_SIZE); 166 tohash_len = POLY1305_BLOCK_SIZE; 167 ctx->len.aad = EVP_AEAD_TLS1_AAD_LEN; 168 ctx->len.text = plen; 169 170 if (bctx->enc) { 171 for (i = 0; i < plen; i++) 172 out[i] = ctr[i] ^= in[i]; 173 } else { 174 for (i = 0; i < plen; i++) { 175 unsigned char c = in[i]; 176 177 out[i] = ctr[i] ^ c; 178 ctr[i] = c; 179 } 180 } 181 182 in += i; 183 out += i; 184 185 tail = (0 - i) & (POLY1305_BLOCK_SIZE - 1); 186 memset(ctr + i, 0, tail); 187 ctr += i + tail; 188 tohash_len += i + tail; 189 } 190 # endif 191 else { 192 ctx->chacha.counter[0] = 0; 193 ChaCha20_ctr32(buf, zero, (buf_len = CHACHA_BLK_SIZE), 194 ctx->chacha.key.d, ctx->chacha.counter); 195 Poly1305_Init(poly, buf); 196 ctx->chacha.counter[0] = 1; 197 ctx->chacha.partial_len = 0; 198 Poly1305_Update(poly, ctx->tls_aad, POLY1305_BLOCK_SIZE); 199 tohash = ctr; 200 tohash_len = 0; 201 ctx->len.aad = EVP_AEAD_TLS1_AAD_LEN; 202 ctx->len.text = plen; 203 204 if (bctx->enc) { 205 ChaCha20_ctr32(out, in, plen, ctx->chacha.key.d, ctx->chacha.counter); 206 Poly1305_Update(poly, out, plen); 207 } else { 208 Poly1305_Update(poly, in, plen); 209 ChaCha20_ctr32(out, in, plen, ctx->chacha.key.d, ctx->chacha.counter); 210 } 211 212 in += plen; 213 out += plen; 214 tail = (0 - plen) & (POLY1305_BLOCK_SIZE - 1); 215 Poly1305_Update(poly, zero, tail); 216 } 217 218 if (IS_LITTLE_ENDIAN) { 219 memcpy(ctr, (unsigned char *)&ctx->len, POLY1305_BLOCK_SIZE); 220 } else { 221 ctr[0] = (unsigned char)(ctx->len.aad); 222 ctr[1] = (unsigned char)(ctx->len.aad>>8); 223 ctr[2] = (unsigned char)(ctx->len.aad>>16); 224 ctr[3] = (unsigned char)(ctx->len.aad>>24); 225 ctr[4] = (unsigned char)(ctx->len.aad>>32); 226 ctr[5] = (unsigned char)(ctx->len.aad>>40); 227 ctr[6] = (unsigned char)(ctx->len.aad>>48); 228 ctr[7] = (unsigned char)(ctx->len.aad>>56); 229 230 ctr[8] = (unsigned char)(ctx->len.text); 231 ctr[9] = (unsigned char)(ctx->len.text>>8); 232 ctr[10] = (unsigned char)(ctx->len.text>>16); 233 ctr[11] = (unsigned char)(ctx->len.text>>24); 234 ctr[12] = (unsigned char)(ctx->len.text>>32); 235 ctr[13] = (unsigned char)(ctx->len.text>>40); 236 ctr[14] = (unsigned char)(ctx->len.text>>48); 237 ctr[15] = (unsigned char)(ctx->len.text>>56); 238 } 239 tohash_len += POLY1305_BLOCK_SIZE; 240 241 Poly1305_Update(poly, tohash, tohash_len); 242 OPENSSL_cleanse(buf, buf_len); 243 Poly1305_Final(poly, bctx->enc ? ctx->tag : tohash); 244 245 ctx->tls_payload_length = NO_TLS_PAYLOAD_LENGTH; 246 247 if (bctx->enc) { 248 memcpy(out, ctx->tag, POLY1305_BLOCK_SIZE); 249 } else { 250 if (CRYPTO_memcmp(tohash, in, POLY1305_BLOCK_SIZE)) { 251 if (len > POLY1305_BLOCK_SIZE) 252 memset(out - (len - POLY1305_BLOCK_SIZE), 0, 253 len - POLY1305_BLOCK_SIZE); 254 return 0; 255 } 256 /* Strip the tag */ 257 len -= POLY1305_BLOCK_SIZE; 258 } 259 260 *out_padlen = len; 261 return 1; 262 } 263 #else 264 static const unsigned char zero[CHACHA_BLK_SIZE] = { 0 }; 265 #endif /* OPENSSL_SMALL_FOOTPRINT */ 266 267 static int chacha20_poly1305_aead_cipher(PROV_CIPHER_CTX *bctx, 268 unsigned char *out, size_t *outl, 269 const unsigned char *in, size_t inl) 270 { 271 PROV_CHACHA20_POLY1305_CTX *ctx = (PROV_CHACHA20_POLY1305_CTX *)bctx; 272 POLY1305 *poly = &ctx->poly1305; 273 size_t rem, plen = ctx->tls_payload_length; 274 size_t olen = 0; 275 int rv = 0; 276 277 DECLARE_IS_ENDIAN; 278 279 if (!ctx->mac_inited) { 280 if (plen != NO_TLS_PAYLOAD_LENGTH && out != NULL) { 281 if (inl != plen + POLY1305_BLOCK_SIZE) 282 return 0; 283 #if !defined(OPENSSL_SMALL_FOOTPRINT) 284 return chacha20_poly1305_tls_cipher(bctx, out, outl, in, inl); 285 #endif 286 } 287 288 ctx->chacha.counter[0] = 0; 289 ChaCha20_ctr32(ctx->chacha.buf, zero, CHACHA_BLK_SIZE, 290 ctx->chacha.key.d, ctx->chacha.counter); 291 Poly1305_Init(poly, ctx->chacha.buf); 292 ctx->chacha.counter[0] = 1; 293 ctx->chacha.partial_len = 0; 294 ctx->len.aad = ctx->len.text = 0; 295 ctx->mac_inited = 1; 296 if (plen != NO_TLS_PAYLOAD_LENGTH) { 297 Poly1305_Update(poly, ctx->tls_aad, EVP_AEAD_TLS1_AAD_LEN); 298 ctx->len.aad = EVP_AEAD_TLS1_AAD_LEN; 299 ctx->aad = 1; 300 } 301 } 302 303 if (in != NULL) { /* aad or text */ 304 if (out == NULL) { /* aad */ 305 Poly1305_Update(poly, in, inl); 306 ctx->len.aad += inl; 307 ctx->aad = 1; 308 goto finish; 309 } else { /* plain- or ciphertext */ 310 if (ctx->aad) { /* wrap up aad */ 311 if ((rem = (size_t)ctx->len.aad % POLY1305_BLOCK_SIZE)) 312 Poly1305_Update(poly, zero, POLY1305_BLOCK_SIZE - rem); 313 ctx->aad = 0; 314 } 315 316 ctx->tls_payload_length = NO_TLS_PAYLOAD_LENGTH; 317 if (plen == NO_TLS_PAYLOAD_LENGTH) 318 plen = inl; 319 else if (inl != plen + POLY1305_BLOCK_SIZE) 320 goto err; 321 322 if (bctx->enc) { /* plaintext */ 323 ctx->chacha.base.hw->cipher(&ctx->chacha.base, out, in, plen); 324 Poly1305_Update(poly, out, plen); 325 in += plen; 326 out += plen; 327 ctx->len.text += plen; 328 } else { /* ciphertext */ 329 Poly1305_Update(poly, in, plen); 330 ctx->chacha.base.hw->cipher(&ctx->chacha.base, out, in, plen); 331 in += plen; 332 out += plen; 333 ctx->len.text += plen; 334 } 335 } 336 } 337 /* explicit final, or tls mode */ 338 if (in == NULL || inl != plen) { 339 340 unsigned char temp[POLY1305_BLOCK_SIZE]; 341 342 if (ctx->aad) { /* wrap up aad */ 343 if ((rem = (size_t)ctx->len.aad % POLY1305_BLOCK_SIZE)) 344 Poly1305_Update(poly, zero, POLY1305_BLOCK_SIZE - rem); 345 ctx->aad = 0; 346 } 347 348 if ((rem = (size_t)ctx->len.text % POLY1305_BLOCK_SIZE)) 349 Poly1305_Update(poly, zero, POLY1305_BLOCK_SIZE - rem); 350 351 if (IS_LITTLE_ENDIAN) { 352 Poly1305_Update(poly, (unsigned char *)&ctx->len, 353 POLY1305_BLOCK_SIZE); 354 } else { 355 temp[0] = (unsigned char)(ctx->len.aad); 356 temp[1] = (unsigned char)(ctx->len.aad>>8); 357 temp[2] = (unsigned char)(ctx->len.aad>>16); 358 temp[3] = (unsigned char)(ctx->len.aad>>24); 359 temp[4] = (unsigned char)(ctx->len.aad>>32); 360 temp[5] = (unsigned char)(ctx->len.aad>>40); 361 temp[6] = (unsigned char)(ctx->len.aad>>48); 362 temp[7] = (unsigned char)(ctx->len.aad>>56); 363 temp[8] = (unsigned char)(ctx->len.text); 364 temp[9] = (unsigned char)(ctx->len.text>>8); 365 temp[10] = (unsigned char)(ctx->len.text>>16); 366 temp[11] = (unsigned char)(ctx->len.text>>24); 367 temp[12] = (unsigned char)(ctx->len.text>>32); 368 temp[13] = (unsigned char)(ctx->len.text>>40); 369 temp[14] = (unsigned char)(ctx->len.text>>48); 370 temp[15] = (unsigned char)(ctx->len.text>>56); 371 Poly1305_Update(poly, temp, POLY1305_BLOCK_SIZE); 372 } 373 Poly1305_Final(poly, bctx->enc ? ctx->tag : temp); 374 ctx->mac_inited = 0; 375 376 if (in != NULL && inl != plen) { 377 if (bctx->enc) { 378 memcpy(out, ctx->tag, POLY1305_BLOCK_SIZE); 379 } else { 380 if (CRYPTO_memcmp(temp, in, POLY1305_BLOCK_SIZE)) { 381 memset(out - plen, 0, plen); 382 goto err; 383 } 384 /* Strip the tag */ 385 inl -= POLY1305_BLOCK_SIZE; 386 } 387 } 388 else if (!bctx->enc) { 389 if (CRYPTO_memcmp(temp, ctx->tag, ctx->tag_len)) 390 goto err; 391 } 392 } 393 finish: 394 olen = inl; 395 rv = 1; 396 err: 397 *outl = olen; 398 return rv; 399 } 400 401 static const PROV_CIPHER_HW_CHACHA20_POLY1305 chacha20poly1305_hw = 402 { 403 { chacha20_poly1305_initkey, NULL }, 404 chacha20_poly1305_aead_cipher, 405 chacha20_poly1305_initiv, 406 chacha_poly1305_tls_init, 407 chacha_poly1305_tls_iv_set_fixed 408 }; 409 410 const PROV_CIPHER_HW *ossl_prov_cipher_hw_chacha20_poly1305(size_t keybits) 411 { 412 return (PROV_CIPHER_HW *)&chacha20poly1305_hw; 413 } 414