1 /*
2 * Copyright 2019-2021 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
chacha_poly1305_tls_init(PROV_CIPHER_CTX * bctx,unsigned char * aad,size_t alen)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
chacha_poly1305_tls_iv_set_fixed(PROV_CIPHER_CTX * bctx,unsigned char * fixed,size_t flen)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
chacha20_poly1305_initkey(PROV_CIPHER_CTX * bctx,const unsigned char * key,size_t keylen)59 static int chacha20_poly1305_initkey(PROV_CIPHER_CTX *bctx,
60 const unsigned char *key, size_t keylen)
61 {
62 PROV_CHACHA20_POLY1305_CTX *ctx = (PROV_CHACHA20_POLY1305_CTX *)bctx;
63
64 ctx->len.aad = 0;
65 ctx->len.text = 0;
66 ctx->aad = 0;
67 ctx->mac_inited = 0;
68 ctx->tls_payload_length = NO_TLS_PAYLOAD_LENGTH;
69
70 if (bctx->enc)
71 return ossl_chacha20_einit(&ctx->chacha, key, keylen, NULL, 0, NULL);
72 else
73 return ossl_chacha20_dinit(&ctx->chacha, key, keylen, NULL, 0, NULL);
74 }
75
chacha20_poly1305_initiv(PROV_CIPHER_CTX * bctx)76 static int chacha20_poly1305_initiv(PROV_CIPHER_CTX *bctx)
77 {
78 PROV_CHACHA20_POLY1305_CTX *ctx = (PROV_CHACHA20_POLY1305_CTX *)bctx;
79 unsigned char tempiv[CHACHA_CTR_SIZE] = { 0 };
80 int ret = 1;
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 if (ctx->nonce_len <= CHACHA_CTR_SIZE) {
90 memcpy(tempiv + CHACHA_CTR_SIZE - ctx->nonce_len, bctx->oiv,
91 ctx->nonce_len);
92
93 if (bctx->enc)
94 ret = ossl_chacha20_einit(&ctx->chacha, NULL, 0,
95 tempiv, sizeof(tempiv), NULL);
96 else
97 ret = ossl_chacha20_dinit(&ctx->chacha, NULL, 0,
98 tempiv, sizeof(tempiv), NULL);
99 ctx->nonce[0] = ctx->chacha.counter[1];
100 ctx->nonce[1] = ctx->chacha.counter[2];
101 ctx->nonce[2] = ctx->chacha.counter[3];
102 bctx->iv_set = 1;
103 }
104 return ret;
105 }
106
107 #if !defined(OPENSSL_SMALL_FOOTPRINT)
108
109 # if defined(POLY1305_ASM) && (defined(__x86_64) || defined(__x86_64__) \
110 || defined(_M_AMD64) || defined(_M_X64))
111 # define XOR128_HELPERS
112 void *xor128_encrypt_n_pad(void *out, const void *inp, void *otp, size_t len);
113 void *xor128_decrypt_n_pad(void *out, const void *inp, void *otp, size_t len);
114 static const unsigned char zero[4 * CHACHA_BLK_SIZE] = { 0 };
115 # else
116 static const unsigned char zero[2 * CHACHA_BLK_SIZE] = { 0 };
117 # endif
118
chacha20_poly1305_tls_cipher(PROV_CIPHER_CTX * bctx,unsigned char * out,size_t * out_padlen,const unsigned char * in,size_t len)119 static int chacha20_poly1305_tls_cipher(PROV_CIPHER_CTX *bctx,
120 unsigned char *out,
121 size_t *out_padlen,
122 const unsigned char *in, size_t len)
123 {
124 PROV_CHACHA20_POLY1305_CTX *ctx = (PROV_CHACHA20_POLY1305_CTX *)bctx;
125 POLY1305 *poly = &ctx->poly1305;
126 size_t tail, tohash_len, buf_len, plen = ctx->tls_payload_length;
127 unsigned char *buf, *tohash, *ctr, storage[sizeof(zero) + 32];
128
129 DECLARE_IS_ENDIAN;
130
131 buf = storage + ((0 - (size_t)storage) & 15); /* align */
132 ctr = buf + CHACHA_BLK_SIZE;
133 tohash = buf + CHACHA_BLK_SIZE - POLY1305_BLOCK_SIZE;
134
135 # ifdef XOR128_HELPERS
136 if (plen <= 3 * CHACHA_BLK_SIZE) {
137 ctx->chacha.counter[0] = 0;
138 buf_len = (plen + 2 * CHACHA_BLK_SIZE - 1) & (0 - CHACHA_BLK_SIZE);
139 ChaCha20_ctr32(buf, zero, buf_len, ctx->chacha.key.d, ctx->chacha.counter);
140 Poly1305_Init(poly, buf);
141 ctx->chacha.partial_len = 0;
142 memcpy(tohash, ctx->tls_aad, POLY1305_BLOCK_SIZE);
143 tohash_len = POLY1305_BLOCK_SIZE;
144 ctx->len.aad = EVP_AEAD_TLS1_AAD_LEN;
145 ctx->len.text = plen;
146
147 if (plen) {
148 if (bctx->enc)
149 ctr = xor128_encrypt_n_pad(out, in, ctr, plen);
150 else
151 ctr = xor128_decrypt_n_pad(out, in, ctr, plen);
152
153 in += plen;
154 out += plen;
155 tohash_len = (size_t)(ctr - tohash);
156 }
157 }
158 # else
159 if (plen <= CHACHA_BLK_SIZE) {
160 size_t i;
161
162 ctx->chacha.counter[0] = 0;
163 ChaCha20_ctr32(buf, zero, (buf_len = 2 * CHACHA_BLK_SIZE),
164 ctx->chacha.key.d, ctx->chacha.counter);
165 Poly1305_Init(poly, buf);
166 ctx->chacha.partial_len = 0;
167 memcpy(tohash, ctx->tls_aad, POLY1305_BLOCK_SIZE);
168 tohash_len = POLY1305_BLOCK_SIZE;
169 ctx->len.aad = EVP_AEAD_TLS1_AAD_LEN;
170 ctx->len.text = plen;
171
172 if (bctx->enc) {
173 for (i = 0; i < plen; i++)
174 out[i] = ctr[i] ^= in[i];
175 } else {
176 for (i = 0; i < plen; i++) {
177 unsigned char c = in[i];
178
179 out[i] = ctr[i] ^ c;
180 ctr[i] = c;
181 }
182 }
183
184 in += i;
185 out += i;
186
187 tail = (0 - i) & (POLY1305_BLOCK_SIZE - 1);
188 memset(ctr + i, 0, tail);
189 ctr += i + tail;
190 tohash_len += i + tail;
191 }
192 # endif
193 else {
194 ctx->chacha.counter[0] = 0;
195 ChaCha20_ctr32(buf, zero, (buf_len = CHACHA_BLK_SIZE),
196 ctx->chacha.key.d, ctx->chacha.counter);
197 Poly1305_Init(poly, buf);
198 ctx->chacha.counter[0] = 1;
199 ctx->chacha.partial_len = 0;
200 Poly1305_Update(poly, ctx->tls_aad, POLY1305_BLOCK_SIZE);
201 tohash = ctr;
202 tohash_len = 0;
203 ctx->len.aad = EVP_AEAD_TLS1_AAD_LEN;
204 ctx->len.text = plen;
205
206 if (bctx->enc) {
207 ChaCha20_ctr32(out, in, plen, ctx->chacha.key.d, ctx->chacha.counter);
208 Poly1305_Update(poly, out, plen);
209 } else {
210 Poly1305_Update(poly, in, plen);
211 ChaCha20_ctr32(out, in, plen, ctx->chacha.key.d, ctx->chacha.counter);
212 }
213
214 in += plen;
215 out += plen;
216 tail = (0 - plen) & (POLY1305_BLOCK_SIZE - 1);
217 Poly1305_Update(poly, zero, tail);
218 }
219
220 if (IS_LITTLE_ENDIAN) {
221 memcpy(ctr, (unsigned char *)&ctx->len, POLY1305_BLOCK_SIZE);
222 } else {
223 ctr[0] = (unsigned char)(ctx->len.aad);
224 ctr[1] = (unsigned char)(ctx->len.aad>>8);
225 ctr[2] = (unsigned char)(ctx->len.aad>>16);
226 ctr[3] = (unsigned char)(ctx->len.aad>>24);
227 ctr[4] = (unsigned char)(ctx->len.aad>>32);
228 ctr[5] = (unsigned char)(ctx->len.aad>>40);
229 ctr[6] = (unsigned char)(ctx->len.aad>>48);
230 ctr[7] = (unsigned char)(ctx->len.aad>>56);
231
232 ctr[8] = (unsigned char)(ctx->len.text);
233 ctr[9] = (unsigned char)(ctx->len.text>>8);
234 ctr[10] = (unsigned char)(ctx->len.text>>16);
235 ctr[11] = (unsigned char)(ctx->len.text>>24);
236 ctr[12] = (unsigned char)(ctx->len.text>>32);
237 ctr[13] = (unsigned char)(ctx->len.text>>40);
238 ctr[14] = (unsigned char)(ctx->len.text>>48);
239 ctr[15] = (unsigned char)(ctx->len.text>>56);
240 }
241 tohash_len += POLY1305_BLOCK_SIZE;
242
243 Poly1305_Update(poly, tohash, tohash_len);
244 OPENSSL_cleanse(buf, buf_len);
245 Poly1305_Final(poly, bctx->enc ? ctx->tag : tohash);
246
247 ctx->tls_payload_length = NO_TLS_PAYLOAD_LENGTH;
248
249 if (bctx->enc) {
250 memcpy(out, ctx->tag, POLY1305_BLOCK_SIZE);
251 } else {
252 if (CRYPTO_memcmp(tohash, in, POLY1305_BLOCK_SIZE)) {
253 if (len > POLY1305_BLOCK_SIZE)
254 memset(out - (len - POLY1305_BLOCK_SIZE), 0,
255 len - POLY1305_BLOCK_SIZE);
256 return 0;
257 }
258 /* Strip the tag */
259 len -= POLY1305_BLOCK_SIZE;
260 }
261
262 *out_padlen = len;
263 return 1;
264 }
265 #else
266 static const unsigned char zero[CHACHA_BLK_SIZE] = { 0 };
267 #endif /* OPENSSL_SMALL_FOOTPRINT */
268
chacha20_poly1305_aead_cipher(PROV_CIPHER_CTX * bctx,unsigned char * out,size_t * outl,const unsigned char * in,size_t inl)269 static int chacha20_poly1305_aead_cipher(PROV_CIPHER_CTX *bctx,
270 unsigned char *out, size_t *outl,
271 const unsigned char *in, size_t inl)
272 {
273 PROV_CHACHA20_POLY1305_CTX *ctx = (PROV_CHACHA20_POLY1305_CTX *)bctx;
274 POLY1305 *poly = &ctx->poly1305;
275 size_t rem, plen = ctx->tls_payload_length;
276 size_t olen = 0;
277 int rv = 0;
278
279 DECLARE_IS_ENDIAN;
280
281 if (!ctx->mac_inited) {
282 if (plen != NO_TLS_PAYLOAD_LENGTH && out != NULL) {
283 if (inl != plen + POLY1305_BLOCK_SIZE)
284 return 0;
285 #if !defined(OPENSSL_SMALL_FOOTPRINT)
286 return chacha20_poly1305_tls_cipher(bctx, out, outl, in, inl);
287 #endif
288 }
289
290 ctx->chacha.counter[0] = 0;
291 ChaCha20_ctr32(ctx->chacha.buf, zero, CHACHA_BLK_SIZE,
292 ctx->chacha.key.d, ctx->chacha.counter);
293 Poly1305_Init(poly, ctx->chacha.buf);
294 ctx->chacha.counter[0] = 1;
295 ctx->chacha.partial_len = 0;
296 ctx->len.aad = ctx->len.text = 0;
297 ctx->mac_inited = 1;
298 if (plen != NO_TLS_PAYLOAD_LENGTH) {
299 Poly1305_Update(poly, ctx->tls_aad, EVP_AEAD_TLS1_AAD_LEN);
300 ctx->len.aad = EVP_AEAD_TLS1_AAD_LEN;
301 ctx->aad = 1;
302 }
303 }
304
305 if (in != NULL) { /* aad or text */
306 if (out == NULL) { /* aad */
307 Poly1305_Update(poly, in, inl);
308 ctx->len.aad += inl;
309 ctx->aad = 1;
310 goto finish;
311 } else { /* plain- or ciphertext */
312 if (ctx->aad) { /* wrap up aad */
313 if ((rem = (size_t)ctx->len.aad % POLY1305_BLOCK_SIZE))
314 Poly1305_Update(poly, zero, POLY1305_BLOCK_SIZE - rem);
315 ctx->aad = 0;
316 }
317
318 ctx->tls_payload_length = NO_TLS_PAYLOAD_LENGTH;
319 if (plen == NO_TLS_PAYLOAD_LENGTH)
320 plen = inl;
321 else if (inl != plen + POLY1305_BLOCK_SIZE)
322 goto err;
323
324 if (bctx->enc) { /* plaintext */
325 ctx->chacha.base.hw->cipher(&ctx->chacha.base, out, in, plen);
326 Poly1305_Update(poly, out, plen);
327 in += plen;
328 out += plen;
329 ctx->len.text += plen;
330 } else { /* ciphertext */
331 Poly1305_Update(poly, in, plen);
332 ctx->chacha.base.hw->cipher(&ctx->chacha.base, out, in, plen);
333 in += plen;
334 out += plen;
335 ctx->len.text += plen;
336 }
337 }
338 }
339 /* explicit final, or tls mode */
340 if (in == NULL || inl != plen) {
341
342 unsigned char temp[POLY1305_BLOCK_SIZE];
343
344 if (ctx->aad) { /* wrap up aad */
345 if ((rem = (size_t)ctx->len.aad % POLY1305_BLOCK_SIZE))
346 Poly1305_Update(poly, zero, POLY1305_BLOCK_SIZE - rem);
347 ctx->aad = 0;
348 }
349
350 if ((rem = (size_t)ctx->len.text % POLY1305_BLOCK_SIZE))
351 Poly1305_Update(poly, zero, POLY1305_BLOCK_SIZE - rem);
352
353 if (IS_LITTLE_ENDIAN) {
354 Poly1305_Update(poly, (unsigned char *)&ctx->len,
355 POLY1305_BLOCK_SIZE);
356 } else {
357 temp[0] = (unsigned char)(ctx->len.aad);
358 temp[1] = (unsigned char)(ctx->len.aad>>8);
359 temp[2] = (unsigned char)(ctx->len.aad>>16);
360 temp[3] = (unsigned char)(ctx->len.aad>>24);
361 temp[4] = (unsigned char)(ctx->len.aad>>32);
362 temp[5] = (unsigned char)(ctx->len.aad>>40);
363 temp[6] = (unsigned char)(ctx->len.aad>>48);
364 temp[7] = (unsigned char)(ctx->len.aad>>56);
365 temp[8] = (unsigned char)(ctx->len.text);
366 temp[9] = (unsigned char)(ctx->len.text>>8);
367 temp[10] = (unsigned char)(ctx->len.text>>16);
368 temp[11] = (unsigned char)(ctx->len.text>>24);
369 temp[12] = (unsigned char)(ctx->len.text>>32);
370 temp[13] = (unsigned char)(ctx->len.text>>40);
371 temp[14] = (unsigned char)(ctx->len.text>>48);
372 temp[15] = (unsigned char)(ctx->len.text>>56);
373 Poly1305_Update(poly, temp, POLY1305_BLOCK_SIZE);
374 }
375 Poly1305_Final(poly, bctx->enc ? ctx->tag : temp);
376 ctx->mac_inited = 0;
377
378 if (in != NULL && inl != plen) {
379 if (bctx->enc) {
380 memcpy(out, ctx->tag, POLY1305_BLOCK_SIZE);
381 } else {
382 if (CRYPTO_memcmp(temp, in, POLY1305_BLOCK_SIZE)) {
383 memset(out - plen, 0, plen);
384 goto err;
385 }
386 /* Strip the tag */
387 inl -= POLY1305_BLOCK_SIZE;
388 }
389 }
390 else if (!bctx->enc) {
391 if (CRYPTO_memcmp(temp, ctx->tag, ctx->tag_len))
392 goto err;
393 }
394 }
395 finish:
396 olen = inl;
397 rv = 1;
398 err:
399 *outl = olen;
400 return rv;
401 }
402
403 static const PROV_CIPHER_HW_CHACHA20_POLY1305 chacha20poly1305_hw =
404 {
405 { chacha20_poly1305_initkey, NULL },
406 chacha20_poly1305_aead_cipher,
407 chacha20_poly1305_initiv,
408 chacha_poly1305_tls_init,
409 chacha_poly1305_tls_iv_set_fixed
410 };
411
ossl_prov_cipher_hw_chacha20_poly1305(size_t keybits)412 const PROV_CIPHER_HW *ossl_prov_cipher_hw_chacha20_poly1305(size_t keybits)
413 {
414 return (PROV_CIPHER_HW *)&chacha20poly1305_hw;
415 }
416