2 * Copyright 2015-2016 The OpenSSL Project Authors. All Rights Reserved.
4 * Licensed under the OpenSSL license (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"
13 #ifndef OPENSSL_NO_CHACHA
15 # include <openssl/evp.h>
16 # include <openssl/objects.h>
17 # include "evp_locl.h"
18 # include "internal/evp_int.h"
19 # include "internal/chacha.h"
23 double align; /* this ensures even sizeof(EVP_CHACHA_KEY)%8==0 */
24 unsigned int d[CHACHA_KEY_SIZE / 4];
26 unsigned int counter[CHACHA_CTR_SIZE / 4];
27 unsigned char buf[CHACHA_BLK_SIZE];
28 unsigned int partial_len;
31 #define data(ctx) ((EVP_CHACHA_KEY *)(ctx)->cipher_data)
33 static int chacha_init_key(EVP_CIPHER_CTX *ctx,
34 const unsigned char user_key[CHACHA_KEY_SIZE],
35 const unsigned char iv[CHACHA_CTR_SIZE], int enc)
37 EVP_CHACHA_KEY *key = data(ctx);
41 for (i = 0; i < CHACHA_KEY_SIZE; i+=4) {
42 key->key.d[i/4] = CHACHA_U8TOU32(user_key+i);
46 for (i = 0; i < CHACHA_CTR_SIZE; i+=4) {
47 key->counter[i/4] = CHACHA_U8TOU32(iv+i);
55 static int chacha_cipher(EVP_CIPHER_CTX * ctx, unsigned char *out,
56 const unsigned char *inp, size_t len)
58 EVP_CHACHA_KEY *key = data(ctx);
59 unsigned int n, rem, ctr32;
61 if ((n = key->partial_len)) {
62 while (len && n < CHACHA_BLK_SIZE) {
63 *out++ = *inp++ ^ key->buf[n++];
71 if (n == CHACHA_BLK_SIZE) {
74 if (key->counter[0] == 0)
79 rem = (unsigned int)(len % CHACHA_BLK_SIZE);
81 ctr32 = key->counter[0];
82 while (len >= CHACHA_BLK_SIZE) {
83 size_t blocks = len / CHACHA_BLK_SIZE;
85 * 1<<28 is just a not-so-small yet not-so-large number...
86 * Below condition is practically never met, but it has to
87 * be checked for code correctness.
89 if (sizeof(size_t)>sizeof(unsigned int) && blocks>(1U<<28))
93 * As ChaCha20_ctr32 operates on 32-bit counter, caller
94 * has to handle overflow. 'if' below detects the
95 * overflow, which is then handled by limiting the
96 * amount of blocks to the exact overflow point...
98 ctr32 += (unsigned int)blocks;
103 blocks *= CHACHA_BLK_SIZE;
104 ChaCha20_ctr32(out, inp, blocks, key->key.d, key->counter);
109 key->counter[0] = ctr32;
110 if (ctr32 == 0) key->counter[1]++;
114 memset(key->buf, 0, sizeof(key->buf));
115 ChaCha20_ctr32(key->buf, key->buf, CHACHA_BLK_SIZE,
116 key->key.d, key->counter);
117 for (n = 0; n < rem; n++)
118 out[n] = inp[n] ^ key->buf[n];
119 key->partial_len = rem;
125 static const EVP_CIPHER chacha20 = {
128 CHACHA_KEY_SIZE, /* key_len */
129 CHACHA_CTR_SIZE, /* iv_len, 128-bit counter in the context */
134 sizeof(EVP_CHACHA_KEY),
141 const EVP_CIPHER *EVP_chacha20(void)
146 # ifndef OPENSSL_NO_POLY1305
147 # include "internal/poly1305.h"
151 unsigned int nonce[12/4];
152 unsigned char tag[POLY1305_BLOCK_SIZE];
153 struct { uint64_t aad, text; } len;
154 int aad, mac_inited, tag_len, nonce_len;
155 size_t tls_payload_length;
156 } EVP_CHACHA_AEAD_CTX;
158 # define NO_TLS_PAYLOAD_LENGTH ((size_t)-1)
159 # define aead_data(ctx) ((EVP_CHACHA_AEAD_CTX *)(ctx)->cipher_data)
160 # define POLY1305_ctx(actx) ((POLY1305 *)(actx + 1))
162 static int chacha20_poly1305_init_key(EVP_CIPHER_CTX *ctx,
163 const unsigned char *inkey,
164 const unsigned char *iv, int enc)
166 EVP_CHACHA_AEAD_CTX *actx = aead_data(ctx);
174 actx->mac_inited = 0;
175 actx->tls_payload_length = NO_TLS_PAYLOAD_LENGTH;
178 unsigned char temp[CHACHA_CTR_SIZE] = { 0 };
180 /* pad on the left */
181 if (actx->nonce_len <= CHACHA_CTR_SIZE)
182 memcpy(temp + CHACHA_CTR_SIZE - actx->nonce_len, iv, actx->nonce_len);
184 chacha_init_key(ctx, inkey, temp, enc);
186 actx->nonce[0] = actx->key.counter[1];
187 actx->nonce[1] = actx->key.counter[2];
188 actx->nonce[2] = actx->key.counter[3];
190 chacha_init_key(ctx, inkey, NULL, enc);
196 static int chacha20_poly1305_cipher(EVP_CIPHER_CTX *ctx, unsigned char *out,
197 const unsigned char *in, size_t len)
199 EVP_CHACHA_AEAD_CTX *actx = aead_data(ctx);
200 size_t rem, plen = actx->tls_payload_length;
201 static const unsigned char zero[POLY1305_BLOCK_SIZE] = { 0 };
203 if (!actx->mac_inited) {
204 actx->key.counter[0] = 0;
205 memset(actx->key.buf, 0, sizeof(actx->key.buf));
206 ChaCha20_ctr32(actx->key.buf, actx->key.buf, CHACHA_BLK_SIZE,
207 actx->key.key.d, actx->key.counter);
208 Poly1305_Init(POLY1305_ctx(actx), actx->key.buf);
209 actx->key.counter[0] = 1;
210 actx->key.partial_len = 0;
211 actx->len.aad = actx->len.text = 0;
212 actx->mac_inited = 1;
215 if (in) { /* aad or text */
216 if (out == NULL) { /* aad */
217 Poly1305_Update(POLY1305_ctx(actx), in, len);
218 actx->len.aad += len;
221 } else { /* plain- or ciphertext */
222 if (actx->aad) { /* wrap up aad */
223 if ((rem = (size_t)actx->len.aad % POLY1305_BLOCK_SIZE))
224 Poly1305_Update(POLY1305_ctx(actx), zero,
225 POLY1305_BLOCK_SIZE - rem);
229 actx->tls_payload_length = NO_TLS_PAYLOAD_LENGTH;
230 if (plen == NO_TLS_PAYLOAD_LENGTH)
232 else if (len != plen + POLY1305_BLOCK_SIZE)
235 if (ctx->encrypt) { /* plaintext */
236 chacha_cipher(ctx, out, in, plen);
237 Poly1305_Update(POLY1305_ctx(actx), out, plen);
240 actx->len.text += plen;
241 } else { /* ciphertext */
242 Poly1305_Update(POLY1305_ctx(actx), in, plen);
243 chacha_cipher(ctx, out, in, plen);
246 actx->len.text += plen;
250 if (in == NULL /* explicit final */
251 || plen != len) { /* or tls mode */
256 unsigned char temp[POLY1305_BLOCK_SIZE];
258 if (actx->aad) { /* wrap up aad */
259 if ((rem = (size_t)actx->len.aad % POLY1305_BLOCK_SIZE))
260 Poly1305_Update(POLY1305_ctx(actx), zero,
261 POLY1305_BLOCK_SIZE - rem);
265 if ((rem = (size_t)actx->len.text % POLY1305_BLOCK_SIZE))
266 Poly1305_Update(POLY1305_ctx(actx), zero,
267 POLY1305_BLOCK_SIZE - rem);
269 if (is_endian.little) {
270 Poly1305_Update(POLY1305_ctx(actx),
271 (unsigned char *)&actx->len, POLY1305_BLOCK_SIZE);
273 temp[0] = (unsigned char)(actx->len.aad);
274 temp[1] = (unsigned char)(actx->len.aad>>8);
275 temp[2] = (unsigned char)(actx->len.aad>>16);
276 temp[3] = (unsigned char)(actx->len.aad>>24);
277 temp[4] = (unsigned char)(actx->len.aad>>32);
278 temp[5] = (unsigned char)(actx->len.aad>>40);
279 temp[6] = (unsigned char)(actx->len.aad>>48);
280 temp[7] = (unsigned char)(actx->len.aad>>56);
282 temp[8] = (unsigned char)(actx->len.text);
283 temp[9] = (unsigned char)(actx->len.text>>8);
284 temp[10] = (unsigned char)(actx->len.text>>16);
285 temp[11] = (unsigned char)(actx->len.text>>24);
286 temp[12] = (unsigned char)(actx->len.text>>32);
287 temp[13] = (unsigned char)(actx->len.text>>40);
288 temp[14] = (unsigned char)(actx->len.text>>48);
289 temp[15] = (unsigned char)(actx->len.text>>56);
291 Poly1305_Update(POLY1305_ctx(actx), temp, POLY1305_BLOCK_SIZE);
293 Poly1305_Final(POLY1305_ctx(actx), ctx->encrypt ? actx->tag
295 actx->mac_inited = 0;
297 if (in != NULL && len != plen) { /* tls mode */
299 memcpy(out, actx->tag, POLY1305_BLOCK_SIZE);
301 if (CRYPTO_memcmp(temp, in, POLY1305_BLOCK_SIZE)) {
302 memset(out, 0, plen);
307 else if (!ctx->encrypt) {
308 if (CRYPTO_memcmp(temp, actx->tag, actx->tag_len))
315 static int chacha20_poly1305_cleanup(EVP_CIPHER_CTX *ctx)
317 EVP_CHACHA_AEAD_CTX *actx = aead_data(ctx);
319 OPENSSL_cleanse(ctx->cipher_data, sizeof(*ctx) + Poly1305_ctx_size());
323 static int chacha20_poly1305_ctrl(EVP_CIPHER_CTX *ctx, int type, int arg,
326 EVP_CHACHA_AEAD_CTX *actx = aead_data(ctx);
331 actx = ctx->cipher_data
332 = OPENSSL_zalloc(sizeof(*actx) + Poly1305_ctx_size());
334 EVPerr(EVP_F_CHACHA20_POLY1305_CTRL, EVP_R_INITIALIZATION_ERROR);
340 actx->mac_inited = 0;
342 actx->nonce_len = 12;
343 actx->tls_payload_length = NO_TLS_PAYLOAD_LENGTH;
348 EVP_CIPHER_CTX *dst = (EVP_CIPHER_CTX *)ptr;
351 OPENSSL_memdup(actx, sizeof(*actx) + Poly1305_ctx_size());
352 if (dst->cipher_data == NULL) {
353 EVPerr(EVP_F_CHACHA20_POLY1305_CTRL, EVP_R_COPY_ERROR);
359 case EVP_CTRL_AEAD_SET_IVLEN:
360 if (arg <= 0 || arg > CHACHA_CTR_SIZE)
362 actx->nonce_len = arg;
365 case EVP_CTRL_AEAD_SET_IV_FIXED:
368 actx->nonce[0] = actx->key.counter[1]
369 = CHACHA_U8TOU32((unsigned char *)ptr);
370 actx->nonce[1] = actx->key.counter[2]
371 = CHACHA_U8TOU32((unsigned char *)ptr+4);
372 actx->nonce[2] = actx->key.counter[3]
373 = CHACHA_U8TOU32((unsigned char *)ptr+8);
376 case EVP_CTRL_AEAD_SET_TAG:
377 if (arg <= 0 || arg > POLY1305_BLOCK_SIZE)
380 memcpy(actx->tag, ptr, arg);
385 case EVP_CTRL_AEAD_GET_TAG:
386 if (arg <= 0 || arg > POLY1305_BLOCK_SIZE || !ctx->encrypt)
388 memcpy(ptr, actx->tag, arg);
391 case EVP_CTRL_AEAD_TLS1_AAD:
392 if (arg != EVP_AEAD_TLS1_AAD_LEN)
396 unsigned char *aad = ptr, temp[POLY1305_BLOCK_SIZE];
398 len = aad[EVP_AEAD_TLS1_AAD_LEN - 2] << 8 |
399 aad[EVP_AEAD_TLS1_AAD_LEN - 1];
401 len -= POLY1305_BLOCK_SIZE; /* discount attached tag */
402 memcpy(temp, aad, EVP_AEAD_TLS1_AAD_LEN - 2);
404 temp[EVP_AEAD_TLS1_AAD_LEN - 2] = (unsigned char)(len >> 8);
405 temp[EVP_AEAD_TLS1_AAD_LEN - 1] = (unsigned char)len;
407 actx->tls_payload_length = len;
410 * merge record sequence number as per
411 * draft-ietf-tls-chacha20-poly1305-03
413 actx->key.counter[1] = actx->nonce[0];
414 actx->key.counter[2] = actx->nonce[1] ^ CHACHA_U8TOU32(aad);
415 actx->key.counter[3] = actx->nonce[2] ^ CHACHA_U8TOU32(aad+4);
416 actx->mac_inited = 0;
417 chacha20_poly1305_cipher(ctx, NULL, aad, EVP_AEAD_TLS1_AAD_LEN);
418 return POLY1305_BLOCK_SIZE; /* tag length */
421 case EVP_CTRL_AEAD_SET_MAC_KEY:
430 static EVP_CIPHER chacha20_poly1305 = {
431 NID_chacha20_poly1305,
433 CHACHA_KEY_SIZE, /* key_len */
434 12, /* iv_len, 96-bit nonce in the context */
435 EVP_CIPH_FLAG_AEAD_CIPHER | EVP_CIPH_CUSTOM_IV |
436 EVP_CIPH_ALWAYS_CALL_INIT | EVP_CIPH_CTRL_INIT |
437 EVP_CIPH_CUSTOM_COPY | EVP_CIPH_FLAG_CUSTOM_CIPHER,
438 chacha20_poly1305_init_key,
439 chacha20_poly1305_cipher,
440 chacha20_poly1305_cleanup,
441 0, /* 0 moves context-specific structure allocation to ctrl */
442 NULL, /* set_asn1_parameters */
443 NULL, /* get_asn1_parameters */
444 chacha20_poly1305_ctrl,
448 const EVP_CIPHER *EVP_chacha20_poly1305(void)
450 return(&chacha20_poly1305);