2 * Copyright 2015-2020 The OpenSSL Project Authors. All Rights Reserved.
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
11 #include "internal/cryptlib.h"
12 #include "internal/endian.h"
14 #ifndef OPENSSL_NO_CHACHA
16 # include <openssl/evp.h>
17 # include <openssl/objects.h>
18 # include "crypto/evp.h"
19 # include "evp_local.h"
20 # include "crypto/chacha.h"
24 OSSL_UNION_ALIGN; /* this ensures even sizeof(EVP_CHACHA_KEY)%8==0 */
25 unsigned int d[CHACHA_KEY_SIZE / 4];
27 unsigned int counter[CHACHA_CTR_SIZE / 4];
28 unsigned char buf[CHACHA_BLK_SIZE];
29 unsigned int partial_len;
32 #define data(ctx) ((EVP_CHACHA_KEY *)(ctx)->cipher_data)
34 #define CHACHA20_POLY1305_MAX_IVLEN 12
36 static int chacha_init_key(EVP_CIPHER_CTX *ctx,
37 const unsigned char user_key[CHACHA_KEY_SIZE],
38 const unsigned char iv[CHACHA_CTR_SIZE], int enc)
40 EVP_CHACHA_KEY *key = data(ctx);
44 for (i = 0; i < CHACHA_KEY_SIZE; i+=4) {
45 key->key.d[i/4] = CHACHA_U8TOU32(user_key+i);
49 for (i = 0; i < CHACHA_CTR_SIZE; i+=4) {
50 key->counter[i/4] = CHACHA_U8TOU32(iv+i);
58 static int chacha_cipher(EVP_CIPHER_CTX * ctx, unsigned char *out,
59 const unsigned char *inp, size_t len)
61 EVP_CHACHA_KEY *key = data(ctx);
62 unsigned int n, rem, ctr32;
64 if ((n = key->partial_len)) {
65 while (len && n < CHACHA_BLK_SIZE) {
66 *out++ = *inp++ ^ key->buf[n++];
74 if (n == CHACHA_BLK_SIZE) {
77 if (key->counter[0] == 0)
82 rem = (unsigned int)(len % CHACHA_BLK_SIZE);
84 ctr32 = key->counter[0];
85 while (len >= CHACHA_BLK_SIZE) {
86 size_t blocks = len / CHACHA_BLK_SIZE;
88 * 1<<28 is just a not-so-small yet not-so-large number...
89 * Below condition is practically never met, but it has to
90 * be checked for code correctness.
92 if (sizeof(size_t)>sizeof(unsigned int) && blocks>(1U<<28))
96 * As ChaCha20_ctr32 operates on 32-bit counter, caller
97 * has to handle overflow. 'if' below detects the
98 * overflow, which is then handled by limiting the
99 * amount of blocks to the exact overflow point...
101 ctr32 += (unsigned int)blocks;
102 if (ctr32 < blocks) {
106 blocks *= CHACHA_BLK_SIZE;
107 ChaCha20_ctr32(out, inp, blocks, key->key.d, key->counter);
112 key->counter[0] = ctr32;
113 if (ctr32 == 0) key->counter[1]++;
117 memset(key->buf, 0, sizeof(key->buf));
118 ChaCha20_ctr32(key->buf, key->buf, CHACHA_BLK_SIZE,
119 key->key.d, key->counter);
120 for (n = 0; n < rem; n++)
121 out[n] = inp[n] ^ key->buf[n];
122 key->partial_len = rem;
128 static const EVP_CIPHER chacha20 = {
131 CHACHA_KEY_SIZE, /* key_len */
132 CHACHA_CTR_SIZE, /* iv_len, 128-bit counter in the context */
133 EVP_CIPH_CUSTOM_IV | EVP_CIPH_ALWAYS_CALL_INIT,
137 sizeof(EVP_CHACHA_KEY),
144 const EVP_CIPHER *EVP_chacha20(void)
149 # ifndef OPENSSL_NO_POLY1305
150 # include "crypto/poly1305.h"
154 unsigned int nonce[12/4];
155 unsigned char tag[POLY1305_BLOCK_SIZE];
156 unsigned char tls_aad[POLY1305_BLOCK_SIZE];
157 struct { uint64_t aad, text; } len;
158 int aad, mac_inited, tag_len, nonce_len;
159 size_t tls_payload_length;
160 } EVP_CHACHA_AEAD_CTX;
162 # define NO_TLS_PAYLOAD_LENGTH ((size_t)-1)
163 # define aead_data(ctx) ((EVP_CHACHA_AEAD_CTX *)(ctx)->cipher_data)
164 # define POLY1305_ctx(actx) ((POLY1305 *)(actx + 1))
166 static int chacha20_poly1305_init_key(EVP_CIPHER_CTX *ctx,
167 const unsigned char *inkey,
168 const unsigned char *iv, int enc)
170 EVP_CHACHA_AEAD_CTX *actx = aead_data(ctx);
178 actx->mac_inited = 0;
179 actx->tls_payload_length = NO_TLS_PAYLOAD_LENGTH;
182 unsigned char temp[CHACHA_CTR_SIZE] = { 0 };
184 /* pad on the left */
185 if (actx->nonce_len <= CHACHA_CTR_SIZE)
186 memcpy(temp + CHACHA_CTR_SIZE - actx->nonce_len, iv,
189 chacha_init_key(ctx, inkey, temp, enc);
191 actx->nonce[0] = actx->key.counter[1];
192 actx->nonce[1] = actx->key.counter[2];
193 actx->nonce[2] = actx->key.counter[3];
195 chacha_init_key(ctx, inkey, NULL, enc);
201 # if !defined(OPENSSL_SMALL_FOOTPRINT)
203 # if defined(POLY1305_ASM) && (defined(__x86_64) || defined(__x86_64__) || \
204 defined(_M_AMD64) || defined(_M_X64))
205 # define XOR128_HELPERS
206 void *xor128_encrypt_n_pad(void *out, const void *inp, void *otp, size_t len);
207 void *xor128_decrypt_n_pad(void *out, const void *inp, void *otp, size_t len);
208 static const unsigned char zero[4 * CHACHA_BLK_SIZE] = { 0 };
210 static const unsigned char zero[2 * CHACHA_BLK_SIZE] = { 0 };
213 static int chacha20_poly1305_tls_cipher(EVP_CIPHER_CTX *ctx, unsigned char *out,
214 const unsigned char *in, size_t len)
216 EVP_CHACHA_AEAD_CTX *actx = aead_data(ctx);
217 size_t tail, tohash_len, buf_len, plen = actx->tls_payload_length;
218 unsigned char *buf, *tohash, *ctr, storage[sizeof(zero) + 32];
220 if (len != plen + POLY1305_BLOCK_SIZE)
223 buf = storage + ((0 - (size_t)storage) & 15); /* align */
224 ctr = buf + CHACHA_BLK_SIZE;
225 tohash = buf + CHACHA_BLK_SIZE - POLY1305_BLOCK_SIZE;
227 # ifdef XOR128_HELPERS
228 if (plen <= 3 * CHACHA_BLK_SIZE) {
229 actx->key.counter[0] = 0;
230 buf_len = (plen + 2 * CHACHA_BLK_SIZE - 1) & (0 - CHACHA_BLK_SIZE);
231 ChaCha20_ctr32(buf, zero, buf_len, actx->key.key.d,
233 Poly1305_Init(POLY1305_ctx(actx), buf);
234 actx->key.partial_len = 0;
235 memcpy(tohash, actx->tls_aad, POLY1305_BLOCK_SIZE);
236 tohash_len = POLY1305_BLOCK_SIZE;
237 actx->len.aad = EVP_AEAD_TLS1_AAD_LEN;
238 actx->len.text = plen;
242 ctr = xor128_encrypt_n_pad(out, in, ctr, plen);
244 ctr = xor128_decrypt_n_pad(out, in, ctr, plen);
248 tohash_len = (size_t)(ctr - tohash);
252 if (plen <= CHACHA_BLK_SIZE) {
255 actx->key.counter[0] = 0;
256 ChaCha20_ctr32(buf, zero, (buf_len = 2 * CHACHA_BLK_SIZE),
257 actx->key.key.d, actx->key.counter);
258 Poly1305_Init(POLY1305_ctx(actx), buf);
259 actx->key.partial_len = 0;
260 memcpy(tohash, actx->tls_aad, POLY1305_BLOCK_SIZE);
261 tohash_len = POLY1305_BLOCK_SIZE;
262 actx->len.aad = EVP_AEAD_TLS1_AAD_LEN;
263 actx->len.text = plen;
266 for (i = 0; i < plen; i++) {
267 out[i] = ctr[i] ^= in[i];
270 for (i = 0; i < plen; i++) {
271 unsigned char c = in[i];
280 tail = (0 - i) & (POLY1305_BLOCK_SIZE - 1);
281 memset(ctr + i, 0, tail);
283 tohash_len += i + tail;
287 actx->key.counter[0] = 0;
288 ChaCha20_ctr32(buf, zero, (buf_len = CHACHA_BLK_SIZE),
289 actx->key.key.d, actx->key.counter);
290 Poly1305_Init(POLY1305_ctx(actx), buf);
291 actx->key.counter[0] = 1;
292 actx->key.partial_len = 0;
293 Poly1305_Update(POLY1305_ctx(actx), actx->tls_aad, POLY1305_BLOCK_SIZE);
296 actx->len.aad = EVP_AEAD_TLS1_AAD_LEN;
297 actx->len.text = plen;
300 ChaCha20_ctr32(out, in, plen, actx->key.key.d, actx->key.counter);
301 Poly1305_Update(POLY1305_ctx(actx), out, plen);
303 Poly1305_Update(POLY1305_ctx(actx), in, plen);
304 ChaCha20_ctr32(out, in, plen, actx->key.key.d, actx->key.counter);
309 tail = (0 - plen) & (POLY1305_BLOCK_SIZE - 1);
310 Poly1305_Update(POLY1305_ctx(actx), zero, tail);
316 if (IS_LITTLE_ENDIAN) {
317 memcpy(ctr, (unsigned char *)&actx->len, POLY1305_BLOCK_SIZE);
319 ctr[0] = (unsigned char)(actx->len.aad);
320 ctr[1] = (unsigned char)(actx->len.aad>>8);
321 ctr[2] = (unsigned char)(actx->len.aad>>16);
322 ctr[3] = (unsigned char)(actx->len.aad>>24);
323 ctr[4] = (unsigned char)(actx->len.aad>>32);
324 ctr[5] = (unsigned char)(actx->len.aad>>40);
325 ctr[6] = (unsigned char)(actx->len.aad>>48);
326 ctr[7] = (unsigned char)(actx->len.aad>>56);
328 ctr[8] = (unsigned char)(actx->len.text);
329 ctr[9] = (unsigned char)(actx->len.text>>8);
330 ctr[10] = (unsigned char)(actx->len.text>>16);
331 ctr[11] = (unsigned char)(actx->len.text>>24);
332 ctr[12] = (unsigned char)(actx->len.text>>32);
333 ctr[13] = (unsigned char)(actx->len.text>>40);
334 ctr[14] = (unsigned char)(actx->len.text>>48);
335 ctr[15] = (unsigned char)(actx->len.text>>56);
337 tohash_len += POLY1305_BLOCK_SIZE;
340 Poly1305_Update(POLY1305_ctx(actx), tohash, tohash_len);
341 OPENSSL_cleanse(buf, buf_len);
342 Poly1305_Final(POLY1305_ctx(actx), ctx->encrypt ? actx->tag
345 actx->tls_payload_length = NO_TLS_PAYLOAD_LENGTH;
348 memcpy(out, actx->tag, POLY1305_BLOCK_SIZE);
350 if (CRYPTO_memcmp(tohash, in, POLY1305_BLOCK_SIZE)) {
351 memset(out - (len - POLY1305_BLOCK_SIZE), 0,
352 len - POLY1305_BLOCK_SIZE);
360 static const unsigned char zero[CHACHA_BLK_SIZE] = { 0 };
363 static int chacha20_poly1305_cipher(EVP_CIPHER_CTX *ctx, unsigned char *out,
364 const unsigned char *in, size_t len)
366 EVP_CHACHA_AEAD_CTX *actx = aead_data(ctx);
367 size_t rem, plen = actx->tls_payload_length;
369 if (!actx->mac_inited) {
370 # if !defined(OPENSSL_SMALL_FOOTPRINT)
371 if (plen != NO_TLS_PAYLOAD_LENGTH && out != NULL)
372 return chacha20_poly1305_tls_cipher(ctx, out, in, len);
374 actx->key.counter[0] = 0;
375 ChaCha20_ctr32(actx->key.buf, zero, CHACHA_BLK_SIZE,
376 actx->key.key.d, actx->key.counter);
377 Poly1305_Init(POLY1305_ctx(actx), actx->key.buf);
378 actx->key.counter[0] = 1;
379 actx->key.partial_len = 0;
380 actx->len.aad = actx->len.text = 0;
381 actx->mac_inited = 1;
382 if (plen != NO_TLS_PAYLOAD_LENGTH) {
383 Poly1305_Update(POLY1305_ctx(actx), actx->tls_aad,
384 EVP_AEAD_TLS1_AAD_LEN);
385 actx->len.aad = EVP_AEAD_TLS1_AAD_LEN;
390 if (in) { /* aad or text */
391 if (out == NULL) { /* aad */
392 Poly1305_Update(POLY1305_ctx(actx), in, len);
393 actx->len.aad += len;
396 } else { /* plain- or ciphertext */
397 if (actx->aad) { /* wrap up aad */
398 if ((rem = (size_t)actx->len.aad % POLY1305_BLOCK_SIZE))
399 Poly1305_Update(POLY1305_ctx(actx), zero,
400 POLY1305_BLOCK_SIZE - rem);
404 actx->tls_payload_length = NO_TLS_PAYLOAD_LENGTH;
405 if (plen == NO_TLS_PAYLOAD_LENGTH)
407 else if (len != plen + POLY1305_BLOCK_SIZE)
410 if (ctx->encrypt) { /* plaintext */
411 chacha_cipher(ctx, out, in, plen);
412 Poly1305_Update(POLY1305_ctx(actx), out, plen);
415 actx->len.text += plen;
416 } else { /* ciphertext */
417 Poly1305_Update(POLY1305_ctx(actx), in, plen);
418 chacha_cipher(ctx, out, in, plen);
421 actx->len.text += plen;
425 if (in == NULL /* explicit final */
426 || plen != len) { /* or tls mode */
428 unsigned char temp[POLY1305_BLOCK_SIZE];
430 if (actx->aad) { /* wrap up aad */
431 if ((rem = (size_t)actx->len.aad % POLY1305_BLOCK_SIZE))
432 Poly1305_Update(POLY1305_ctx(actx), zero,
433 POLY1305_BLOCK_SIZE - rem);
437 if ((rem = (size_t)actx->len.text % POLY1305_BLOCK_SIZE))
438 Poly1305_Update(POLY1305_ctx(actx), zero,
439 POLY1305_BLOCK_SIZE - rem);
441 if (IS_LITTLE_ENDIAN) {
442 Poly1305_Update(POLY1305_ctx(actx),
443 (unsigned char *)&actx->len, POLY1305_BLOCK_SIZE);
445 temp[0] = (unsigned char)(actx->len.aad);
446 temp[1] = (unsigned char)(actx->len.aad>>8);
447 temp[2] = (unsigned char)(actx->len.aad>>16);
448 temp[3] = (unsigned char)(actx->len.aad>>24);
449 temp[4] = (unsigned char)(actx->len.aad>>32);
450 temp[5] = (unsigned char)(actx->len.aad>>40);
451 temp[6] = (unsigned char)(actx->len.aad>>48);
452 temp[7] = (unsigned char)(actx->len.aad>>56);
454 temp[8] = (unsigned char)(actx->len.text);
455 temp[9] = (unsigned char)(actx->len.text>>8);
456 temp[10] = (unsigned char)(actx->len.text>>16);
457 temp[11] = (unsigned char)(actx->len.text>>24);
458 temp[12] = (unsigned char)(actx->len.text>>32);
459 temp[13] = (unsigned char)(actx->len.text>>40);
460 temp[14] = (unsigned char)(actx->len.text>>48);
461 temp[15] = (unsigned char)(actx->len.text>>56);
463 Poly1305_Update(POLY1305_ctx(actx), temp, POLY1305_BLOCK_SIZE);
465 Poly1305_Final(POLY1305_ctx(actx), ctx->encrypt ? actx->tag
467 actx->mac_inited = 0;
469 if (in != NULL && len != plen) { /* tls mode */
471 memcpy(out, actx->tag, POLY1305_BLOCK_SIZE);
473 if (CRYPTO_memcmp(temp, in, POLY1305_BLOCK_SIZE)) {
474 memset(out - plen, 0, plen);
479 else if (!ctx->encrypt) {
480 if (CRYPTO_memcmp(temp, actx->tag, actx->tag_len))
487 static int chacha20_poly1305_cleanup(EVP_CIPHER_CTX *ctx)
489 EVP_CHACHA_AEAD_CTX *actx = aead_data(ctx);
491 OPENSSL_cleanse(ctx->cipher_data, sizeof(*actx) + Poly1305_ctx_size());
495 static int chacha20_poly1305_ctrl(EVP_CIPHER_CTX *ctx, int type, int arg,
498 EVP_CHACHA_AEAD_CTX *actx = aead_data(ctx);
503 actx = ctx->cipher_data
504 = OPENSSL_zalloc(sizeof(*actx) + Poly1305_ctx_size());
506 EVPerr(EVP_F_CHACHA20_POLY1305_CTRL, EVP_R_INITIALIZATION_ERROR);
512 actx->mac_inited = 0;
514 actx->nonce_len = 12;
515 actx->tls_payload_length = NO_TLS_PAYLOAD_LENGTH;
516 memset(actx->tls_aad, 0, POLY1305_BLOCK_SIZE);
521 EVP_CIPHER_CTX *dst = (EVP_CIPHER_CTX *)ptr;
524 OPENSSL_memdup(actx, sizeof(*actx) + Poly1305_ctx_size());
525 if (dst->cipher_data == NULL) {
526 EVPerr(EVP_F_CHACHA20_POLY1305_CTRL, EVP_R_COPY_ERROR);
532 case EVP_CTRL_GET_IVLEN:
533 *(int *)ptr = actx->nonce_len;
536 case EVP_CTRL_AEAD_SET_IVLEN:
537 if (arg <= 0 || arg > CHACHA20_POLY1305_MAX_IVLEN)
539 actx->nonce_len = arg;
542 case EVP_CTRL_AEAD_SET_IV_FIXED:
545 actx->nonce[0] = actx->key.counter[1]
546 = CHACHA_U8TOU32((unsigned char *)ptr);
547 actx->nonce[1] = actx->key.counter[2]
548 = CHACHA_U8TOU32((unsigned char *)ptr+4);
549 actx->nonce[2] = actx->key.counter[3]
550 = CHACHA_U8TOU32((unsigned char *)ptr+8);
553 case EVP_CTRL_AEAD_SET_TAG:
554 if (arg <= 0 || arg > POLY1305_BLOCK_SIZE)
557 memcpy(actx->tag, ptr, arg);
562 case EVP_CTRL_AEAD_GET_TAG:
563 if (arg <= 0 || arg > POLY1305_BLOCK_SIZE || !ctx->encrypt)
565 memcpy(ptr, actx->tag, arg);
568 case EVP_CTRL_AEAD_TLS1_AAD:
569 if (arg != EVP_AEAD_TLS1_AAD_LEN)
573 unsigned char *aad = ptr;
575 memcpy(actx->tls_aad, ptr, EVP_AEAD_TLS1_AAD_LEN);
576 len = aad[EVP_AEAD_TLS1_AAD_LEN - 2] << 8 |
577 aad[EVP_AEAD_TLS1_AAD_LEN - 1];
580 if (len < POLY1305_BLOCK_SIZE)
582 len -= POLY1305_BLOCK_SIZE; /* discount attached tag */
583 aad[EVP_AEAD_TLS1_AAD_LEN - 2] = (unsigned char)(len >> 8);
584 aad[EVP_AEAD_TLS1_AAD_LEN - 1] = (unsigned char)len;
586 actx->tls_payload_length = len;
589 * merge record sequence number as per RFC7905
591 actx->key.counter[1] = actx->nonce[0];
592 actx->key.counter[2] = actx->nonce[1] ^ CHACHA_U8TOU32(aad);
593 actx->key.counter[3] = actx->nonce[2] ^ CHACHA_U8TOU32(aad+4);
594 actx->mac_inited = 0;
596 return POLY1305_BLOCK_SIZE; /* tag length */
599 case EVP_CTRL_AEAD_SET_MAC_KEY:
608 static EVP_CIPHER chacha20_poly1305 = {
609 NID_chacha20_poly1305,
611 CHACHA_KEY_SIZE, /* key_len */
612 12, /* iv_len, 96-bit nonce in the context */
613 EVP_CIPH_FLAG_AEAD_CIPHER | EVP_CIPH_CUSTOM_IV |
614 EVP_CIPH_ALWAYS_CALL_INIT | EVP_CIPH_CTRL_INIT |
615 EVP_CIPH_CUSTOM_COPY | EVP_CIPH_FLAG_CUSTOM_CIPHER |
616 EVP_CIPH_CUSTOM_IV_LENGTH,
617 chacha20_poly1305_init_key,
618 chacha20_poly1305_cipher,
619 chacha20_poly1305_cleanup,
620 0, /* 0 moves context-specific structure allocation to ctrl */
621 NULL, /* set_asn1_parameters */
622 NULL, /* get_asn1_parameters */
623 chacha20_poly1305_ctrl,
627 const EVP_CIPHER *EVP_chacha20_poly1305(void)
629 return(&chacha20_poly1305);