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62867571 RS |
1 | /* |
2 | * Copyright 2015-2016 The OpenSSL Project Authors. All Rights Reserved. | |
bd989745 | 3 | * |
62867571 RS |
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 | |
bd989745 AP |
8 | */ |
9 | ||
10 | #include <stdio.h> | |
11 | #include "internal/cryptlib.h" | |
12 | ||
13 | #ifndef OPENSSL_NO_CHACHA | |
14 | ||
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" | |
20 | ||
21 | typedef struct { | |
22 | union { | |
23 | double align; /* this ensures even sizeof(EVP_CHACHA_KEY)%8==0 */ | |
24 | unsigned int d[CHACHA_KEY_SIZE / 4]; | |
25 | } key; | |
26 | unsigned int counter[CHACHA_CTR_SIZE / 4]; | |
27 | unsigned char buf[CHACHA_BLK_SIZE]; | |
28 | unsigned int partial_len; | |
29 | } EVP_CHACHA_KEY; | |
30 | ||
31 | #define data(ctx) ((EVP_CHACHA_KEY *)(ctx)->cipher_data) | |
32 | ||
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) | |
36 | { | |
37 | EVP_CHACHA_KEY *key = data(ctx); | |
38 | unsigned int i; | |
39 | ||
40 | if (user_key) | |
41 | for (i = 0; i < CHACHA_KEY_SIZE; i+=4) { | |
42 | key->key.d[i/4] = CHACHA_U8TOU32(user_key+i); | |
43 | } | |
44 | ||
45 | if (iv) | |
46 | for (i = 0; i < CHACHA_CTR_SIZE; i+=4) { | |
47 | key->counter[i/4] = CHACHA_U8TOU32(iv+i); | |
48 | } | |
49 | ||
50 | key->partial_len = 0; | |
51 | ||
52 | return 1; | |
53 | } | |
54 | ||
55 | static int chacha_cipher(EVP_CIPHER_CTX * ctx, unsigned char *out, | |
56 | const unsigned char *inp, size_t len) | |
57 | { | |
58 | EVP_CHACHA_KEY *key = data(ctx); | |
59 | unsigned int n, rem, ctr32; | |
60 | ||
61 | if ((n = key->partial_len)) { | |
62 | while (len && n < CHACHA_BLK_SIZE) { | |
63 | *out++ = *inp++ ^ key->buf[n++]; | |
64 | len--; | |
65 | } | |
66 | key->partial_len = n; | |
67 | ||
68 | if (len == 0) | |
69 | return 1; | |
70 | ||
71 | if (n == CHACHA_BLK_SIZE) { | |
72 | key->partial_len = 0; | |
73 | key->counter[0]++; | |
74 | if (key->counter[0] == 0) | |
75 | key->counter[1]++; | |
76 | } | |
77 | } | |
78 | ||
79 | rem = (unsigned int)(len % CHACHA_BLK_SIZE); | |
80 | len -= rem; | |
81 | ctr32 = key->counter[0]; | |
82 | while (len >= CHACHA_BLK_SIZE) { | |
83 | size_t blocks = len / CHACHA_BLK_SIZE; | |
84 | /* | |
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. | |
88 | */ | |
89 | if (sizeof(size_t)>sizeof(unsigned int) && blocks>(1U<<28)) | |
90 | blocks = (1U<<28); | |
91 | ||
92 | /* | |
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... | |
97 | */ | |
98 | ctr32 += (unsigned int)blocks; | |
99 | if (ctr32 < blocks) { | |
100 | blocks -= ctr32; | |
101 | ctr32 = 0; | |
102 | } | |
103 | blocks *= CHACHA_BLK_SIZE; | |
104 | ChaCha20_ctr32(out, inp, blocks, key->key.d, key->counter); | |
105 | len -= blocks; | |
106 | inp += blocks; | |
107 | out += blocks; | |
108 | ||
109 | key->counter[0] = ctr32; | |
110 | if (ctr32 == 0) key->counter[1]++; | |
111 | } | |
112 | ||
113 | if (rem) { | |
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; | |
120 | } | |
121 | ||
122 | return 1; | |
123 | } | |
124 | ||
125 | static const EVP_CIPHER chacha20 = { | |
126 | NID_chacha20, | |
127 | 1, /* block_size */ | |
128 | CHACHA_KEY_SIZE, /* key_len */ | |
129 | CHACHA_CTR_SIZE, /* iv_len, 128-bit counter in the context */ | |
130 | 0, /* flags */ | |
131 | chacha_init_key, | |
132 | chacha_cipher, | |
133 | NULL, | |
134 | sizeof(EVP_CHACHA_KEY), | |
135 | NULL, | |
136 | NULL, | |
137 | NULL, | |
138 | NULL | |
139 | }; | |
140 | ||
141 | const EVP_CIPHER *EVP_chacha20(void) | |
142 | { | |
143 | return (&chacha20); | |
144 | } | |
145 | ||
146 | # ifndef OPENSSL_NO_POLY1305 | |
147 | # include "internal/poly1305.h" | |
148 | ||
149 | typedef struct { | |
150 | EVP_CHACHA_KEY key; | |
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; | |
157 | ||
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)) | |
161 | ||
162 | static int chacha20_poly1305_init_key(EVP_CIPHER_CTX *ctx, | |
163 | const unsigned char *inkey, | |
164 | const unsigned char *iv, int enc) | |
165 | { | |
166 | EVP_CHACHA_AEAD_CTX *actx = aead_data(ctx); | |
bd989745 AP |
167 | |
168 | if (!inkey && !iv) | |
169 | return 1; | |
170 | ||
171 | actx->len.aad = 0; | |
172 | actx->len.text = 0; | |
173 | actx->aad = 0; | |
174 | actx->mac_inited = 0; | |
175 | actx->tls_payload_length = NO_TLS_PAYLOAD_LENGTH; | |
176 | ||
d2dfd482 KY |
177 | if (iv != NULL) { |
178 | unsigned char temp[CHACHA_CTR_SIZE] = { 0 }; | |
bd989745 | 179 | |
d2dfd482 KY |
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); | |
bd989745 | 183 | |
d2dfd482 KY |
184 | chacha_init_key(ctx, inkey, temp, enc); |
185 | ||
186 | actx->nonce[0] = actx->key.counter[1]; | |
187 | actx->nonce[1] = actx->key.counter[2]; | |
188 | actx->nonce[2] = actx->key.counter[3]; | |
189 | } else { | |
190 | chacha_init_key(ctx, inkey, NULL, enc); | |
191 | } | |
bd989745 AP |
192 | |
193 | return 1; | |
194 | } | |
195 | ||
196 | static int chacha20_poly1305_cipher(EVP_CIPHER_CTX *ctx, unsigned char *out, | |
197 | const unsigned char *in, size_t len) | |
198 | { | |
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 }; | |
202 | ||
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; | |
30a5f322 AP |
210 | actx->key.partial_len = 0; |
211 | actx->len.aad = actx->len.text = 0; | |
bd989745 AP |
212 | actx->mac_inited = 1; |
213 | } | |
214 | ||
215 | if (in) { /* aad or text */ | |
216 | if (out == NULL) { /* aad */ | |
217 | Poly1305_Update(POLY1305_ctx(actx), in, len); | |
218 | actx->len.aad += len; | |
219 | actx->aad = 1; | |
220 | return 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); | |
226 | actx->aad = 0; | |
227 | } | |
228 | ||
229 | actx->tls_payload_length = NO_TLS_PAYLOAD_LENGTH; | |
230 | if (plen == NO_TLS_PAYLOAD_LENGTH) | |
231 | plen = len; | |
232 | else if (len != plen + POLY1305_BLOCK_SIZE) | |
233 | return -1; | |
234 | ||
235 | if (ctx->encrypt) { /* plaintext */ | |
236 | chacha_cipher(ctx, out, in, plen); | |
237 | Poly1305_Update(POLY1305_ctx(actx), out, plen); | |
238 | in += plen; | |
239 | 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); | |
244 | in += plen; | |
245 | out += plen; | |
246 | actx->len.text += plen; | |
247 | } | |
248 | } | |
249 | } | |
250 | if (in == NULL /* explicit final */ | |
251 | || plen != len) { /* or tls mode */ | |
252 | const union { | |
253 | long one; | |
254 | char little; | |
255 | } is_endian = { 1 }; | |
256 | unsigned char temp[POLY1305_BLOCK_SIZE]; | |
257 | ||
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); | |
262 | actx->aad = 0; | |
263 | } | |
264 | ||
265 | if ((rem = (size_t)actx->len.text % POLY1305_BLOCK_SIZE)) | |
266 | Poly1305_Update(POLY1305_ctx(actx), zero, | |
267 | POLY1305_BLOCK_SIZE - rem); | |
268 | ||
269 | if (is_endian.little) { | |
270 | Poly1305_Update(POLY1305_ctx(actx), | |
271 | (unsigned char *)&actx->len, POLY1305_BLOCK_SIZE); | |
272 | } else { | |
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); | |
281 | ||
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); | |
290 | ||
291 | Poly1305_Update(POLY1305_ctx(actx), temp, POLY1305_BLOCK_SIZE); | |
292 | } | |
293 | Poly1305_Final(POLY1305_ctx(actx), ctx->encrypt ? actx->tag | |
294 | : temp); | |
295 | actx->mac_inited = 0; | |
296 | ||
297 | if (in != NULL && len != plen) { /* tls mode */ | |
298 | if (ctx->encrypt) { | |
299 | memcpy(out, actx->tag, POLY1305_BLOCK_SIZE); | |
300 | } else { | |
301 | if (CRYPTO_memcmp(temp, in, POLY1305_BLOCK_SIZE)) { | |
302 | memset(out, 0, plen); | |
303 | return -1; | |
304 | } | |
305 | } | |
306 | } | |
307 | else if (!ctx->encrypt) { | |
308 | if (CRYPTO_memcmp(temp, actx->tag, actx->tag_len)) | |
309 | return -1; | |
310 | } | |
311 | } | |
312 | return len; | |
313 | } | |
314 | ||
315 | static int chacha20_poly1305_cleanup(EVP_CIPHER_CTX *ctx) | |
316 | { | |
317 | EVP_CHACHA_AEAD_CTX *actx = aead_data(ctx); | |
318 | if (actx) | |
319 | OPENSSL_cleanse(ctx->cipher_data, sizeof(*ctx) + Poly1305_ctx_size()); | |
320 | return 1; | |
321 | } | |
322 | ||
323 | static int chacha20_poly1305_ctrl(EVP_CIPHER_CTX *ctx, int type, int arg, | |
324 | void *ptr) | |
325 | { | |
326 | EVP_CHACHA_AEAD_CTX *actx = aead_data(ctx); | |
327 | ||
328 | switch(type) { | |
329 | case EVP_CTRL_INIT: | |
330 | if (actx == NULL) | |
331 | actx = ctx->cipher_data | |
332 | = OPENSSL_zalloc(sizeof(*actx) + Poly1305_ctx_size()); | |
333 | if (actx == NULL) { | |
334 | EVPerr(EVP_F_CHACHA20_POLY1305_CTRL, EVP_R_INITIALIZATION_ERROR); | |
335 | return 0; | |
336 | } | |
337 | actx->len.aad = 0; | |
338 | actx->len.text = 0; | |
339 | actx->aad = 0; | |
340 | actx->mac_inited = 0; | |
341 | actx->tag_len = 0; | |
342 | actx->nonce_len = 12; | |
343 | actx->tls_payload_length = NO_TLS_PAYLOAD_LENGTH; | |
344 | return 1; | |
345 | ||
346 | case EVP_CTRL_COPY: | |
347 | if (actx) { | |
700b8145 F |
348 | EVP_CIPHER_CTX *dst = (EVP_CIPHER_CTX *)ptr; |
349 | ||
350 | dst->cipher_data = | |
351 | OPENSSL_memdup(actx, sizeof(*actx) + Poly1305_ctx_size()); | |
352 | if (dst->cipher_data == NULL) { | |
bd989745 AP |
353 | EVPerr(EVP_F_CHACHA20_POLY1305_CTRL, EVP_R_COPY_ERROR); |
354 | return 0; | |
355 | } | |
356 | } | |
357 | return 1; | |
358 | ||
359 | case EVP_CTRL_AEAD_SET_IVLEN: | |
360 | if (arg <= 0 || arg > CHACHA_CTR_SIZE) | |
361 | return 0; | |
362 | actx->nonce_len = arg; | |
363 | return 1; | |
364 | ||
365 | case EVP_CTRL_AEAD_SET_IV_FIXED: | |
366 | if (arg != 12) | |
367 | return 0; | |
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); | |
374 | return 1; | |
375 | ||
376 | case EVP_CTRL_AEAD_SET_TAG: | |
377 | if (arg <= 0 || arg > POLY1305_BLOCK_SIZE) | |
378 | return 0; | |
379 | if (ptr != NULL) { | |
380 | memcpy(actx->tag, ptr, arg); | |
381 | actx->tag_len = arg; | |
382 | } | |
383 | return 1; | |
384 | ||
385 | case EVP_CTRL_AEAD_GET_TAG: | |
386 | if (arg <= 0 || arg > POLY1305_BLOCK_SIZE || !ctx->encrypt) | |
387 | return 0; | |
388 | memcpy(ptr, actx->tag, arg); | |
389 | return 1; | |
390 | ||
391 | case EVP_CTRL_AEAD_TLS1_AAD: | |
392 | if (arg != EVP_AEAD_TLS1_AAD_LEN) | |
393 | return 0; | |
394 | { | |
395 | unsigned int len; | |
30a5f322 | 396 | unsigned char *aad = ptr, temp[POLY1305_BLOCK_SIZE]; |
bd989745 | 397 | |
30a5f322 AP |
398 | len = aad[EVP_AEAD_TLS1_AAD_LEN - 2] << 8 | |
399 | aad[EVP_AEAD_TLS1_AAD_LEN - 1]; | |
bd989745 AP |
400 | if (!ctx->encrypt) { |
401 | len -= POLY1305_BLOCK_SIZE; /* discount attached tag */ | |
30a5f322 AP |
402 | memcpy(temp, aad, EVP_AEAD_TLS1_AAD_LEN - 2); |
403 | aad = temp; | |
bd989745 AP |
404 | temp[EVP_AEAD_TLS1_AAD_LEN - 2] = (unsigned char)(len >> 8); |
405 | temp[EVP_AEAD_TLS1_AAD_LEN - 1] = (unsigned char)len; | |
406 | } | |
407 | actx->tls_payload_length = len; | |
408 | ||
409 | /* | |
410 | * merge record sequence number as per | |
411 | * draft-ietf-tls-chacha20-poly1305-03 | |
412 | */ | |
413 | actx->key.counter[1] = actx->nonce[0]; | |
30a5f322 AP |
414 | actx->key.counter[2] = actx->nonce[1] ^ CHACHA_U8TOU32(aad); |
415 | actx->key.counter[3] = actx->nonce[2] ^ CHACHA_U8TOU32(aad+4); | |
bd989745 | 416 | actx->mac_inited = 0; |
30a5f322 | 417 | chacha20_poly1305_cipher(ctx, NULL, aad, EVP_AEAD_TLS1_AAD_LEN); |
bd989745 AP |
418 | return POLY1305_BLOCK_SIZE; /* tag length */ |
419 | } | |
420 | ||
421 | case EVP_CTRL_AEAD_SET_MAC_KEY: | |
422 | /* no-op */ | |
423 | return 1; | |
424 | ||
425 | default: | |
426 | return -1; | |
427 | } | |
428 | } | |
429 | ||
430 | static EVP_CIPHER chacha20_poly1305 = { | |
431 | NID_chacha20_poly1305, | |
432 | 1, /* block_size */ | |
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, | |
445 | NULL /* app_data */ | |
446 | }; | |
447 | ||
448 | const EVP_CIPHER *EVP_chacha20_poly1305(void) | |
449 | { | |
450 | return(&chacha20_poly1305); | |
451 | } | |
452 | # endif | |
453 | #endif |