1 /*
2 * Copyright 2022-2024 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 #include <openssl/evp.h>
11 #include <openssl/core_names.h>
12 #include "../../ssl_local.h"
13 #include "../record_local.h"
14 #include "recmethod_local.h"
15
tls13_set_crypto_state(OSSL_RECORD_LAYER * rl,int level,unsigned char * key,size_t keylen,unsigned char * iv,size_t ivlen,unsigned char * mackey,size_t mackeylen,const EVP_CIPHER * ciph,size_t taglen,int mactype,const EVP_MD * md,COMP_METHOD * comp)16 static int tls13_set_crypto_state(OSSL_RECORD_LAYER *rl, int level,
17 unsigned char *key, size_t keylen,
18 unsigned char *iv, size_t ivlen,
19 unsigned char *mackey, size_t mackeylen,
20 const EVP_CIPHER *ciph,
21 size_t taglen,
22 int mactype,
23 const EVP_MD *md,
24 COMP_METHOD *comp)
25 {
26 EVP_CIPHER_CTX *ciph_ctx;
27 EVP_MAC_CTX *mac_ctx;
28 EVP_MAC *mac;
29 OSSL_PARAM params[2], *p = params;
30 int mode;
31 int enc = (rl->direction == OSSL_RECORD_DIRECTION_WRITE) ? 1 : 0;
32
33 rl->iv = OPENSSL_malloc(ivlen);
34 if (rl->iv == NULL)
35 return OSSL_RECORD_RETURN_FATAL;
36
37 rl->nonce = OPENSSL_malloc(ivlen);
38 if (rl->nonce == NULL)
39 return OSSL_RECORD_RETURN_FATAL;
40
41 memcpy(rl->iv, iv, ivlen);
42
43 /* Integrity only */
44 if (EVP_CIPHER_is_a(ciph, "NULL") && mactype == NID_hmac && md != NULL) {
45 mac = EVP_MAC_fetch(rl->libctx, "HMAC", rl->propq);
46 if (mac == NULL
47 || (mac_ctx = rl->mac_ctx = EVP_MAC_CTX_new(mac)) == NULL) {
48 EVP_MAC_free(mac);
49 ERR_raise(ERR_LIB_SSL, ERR_R_INTERNAL_ERROR);
50 return OSSL_RECORD_RETURN_FATAL;
51 }
52 EVP_MAC_free(mac);
53 *p++ = OSSL_PARAM_construct_utf8_string(OSSL_MAC_PARAM_DIGEST,
54 (char *)EVP_MD_name(md), 0);
55 *p = OSSL_PARAM_construct_end();
56 if (!EVP_MAC_init(mac_ctx, key, keylen, params)) {
57 ERR_raise(ERR_LIB_SSL, ERR_R_INTERNAL_ERROR);
58 return OSSL_RECORD_RETURN_FATAL;
59 }
60 goto end;
61 }
62
63 ciph_ctx = rl->enc_ctx = EVP_CIPHER_CTX_new();
64 if (ciph_ctx == NULL) {
65 ERR_raise(ERR_LIB_SSL, ERR_R_INTERNAL_ERROR);
66 return OSSL_RECORD_RETURN_FATAL;
67 }
68
69 mode = EVP_CIPHER_get_mode(ciph);
70
71 if (EVP_CipherInit_ex(ciph_ctx, ciph, NULL, NULL, NULL, enc) <= 0
72 || EVP_CIPHER_CTX_ctrl(ciph_ctx, EVP_CTRL_AEAD_SET_IVLEN, ivlen,
73 NULL) <= 0
74 || (mode == EVP_CIPH_CCM_MODE
75 && EVP_CIPHER_CTX_ctrl(ciph_ctx, EVP_CTRL_AEAD_SET_TAG, taglen,
76 NULL) <= 0)
77 || EVP_CipherInit_ex(ciph_ctx, NULL, NULL, key, NULL, enc) <= 0) {
78 ERR_raise(ERR_LIB_SSL, ERR_R_INTERNAL_ERROR);
79 return OSSL_RECORD_RETURN_FATAL;
80 }
81 end:
82 return OSSL_RECORD_RETURN_SUCCESS;
83 }
84
tls13_cipher(OSSL_RECORD_LAYER * rl,TLS_RL_RECORD * recs,size_t n_recs,int sending,SSL_MAC_BUF * mac,size_t macsize)85 static int tls13_cipher(OSSL_RECORD_LAYER *rl, TLS_RL_RECORD *recs,
86 size_t n_recs, int sending, SSL_MAC_BUF *mac,
87 size_t macsize)
88 {
89 EVP_CIPHER_CTX *enc_ctx;
90 unsigned char recheader[SSL3_RT_HEADER_LENGTH];
91 unsigned char tag[EVP_MAX_MD_SIZE];
92 size_t nonce_len, offset, loop, hdrlen, taglen;
93 unsigned char *staticiv;
94 unsigned char *nonce;
95 unsigned char *seq = rl->sequence;
96 int lenu, lenf;
97 TLS_RL_RECORD *rec = &recs[0];
98 WPACKET wpkt;
99 const EVP_CIPHER *cipher;
100 EVP_MAC_CTX *mac_ctx = NULL;
101 int mode;
102
103 if (n_recs != 1) {
104 /* Should not happen */
105 RLAYERfatal(rl, SSL_AD_INTERNAL_ERROR, ERR_R_INTERNAL_ERROR);
106 return 0;
107 }
108
109 enc_ctx = rl->enc_ctx; /* enc_ctx is ignored when rl->mac_ctx != NULL */
110 staticiv = rl->iv;
111 nonce = rl->nonce;
112
113 if (enc_ctx == NULL && rl->mac_ctx == NULL) {
114 RLAYERfatal(rl, SSL_AD_INTERNAL_ERROR, ERR_R_INTERNAL_ERROR);
115 return 0;
116 }
117
118 /*
119 * If we're sending an alert and ctx != NULL then we must be forcing
120 * plaintext alerts. If we're reading and ctx != NULL then we allow
121 * plaintext alerts at certain points in the handshake. If we've got this
122 * far then we have already validated that a plaintext alert is ok here.
123 */
124 if (rec->type == SSL3_RT_ALERT) {
125 memmove(rec->data, rec->input, rec->length);
126 rec->input = rec->data;
127 return 1;
128 }
129
130 /* For integrity-only ciphers, nonce_len is same as MAC size */
131 if (rl->mac_ctx != NULL) {
132 nonce_len = EVP_MAC_CTX_get_mac_size(rl->mac_ctx);
133 } else {
134 int ivlen = EVP_CIPHER_CTX_get_iv_length(enc_ctx);
135
136 if (ivlen < 0) {
137 /* Should not happen */
138 RLAYERfatal(rl, SSL_AD_INTERNAL_ERROR, ERR_R_INTERNAL_ERROR);
139 return 0;
140 }
141 nonce_len = (size_t)ivlen;
142 }
143
144 if (!sending) {
145 /*
146 * Take off tag. There must be at least one byte of content type as
147 * well as the tag
148 */
149 if (rec->length < rl->taglen + 1)
150 return 0;
151 rec->length -= rl->taglen;
152 }
153
154 /* Set up nonce: part of static IV followed by sequence number */
155 if (nonce_len < SEQ_NUM_SIZE) {
156 /* Should not happen */
157 RLAYERfatal(rl, SSL_AD_INTERNAL_ERROR, ERR_R_INTERNAL_ERROR);
158 return 0;
159 }
160 offset = nonce_len - SEQ_NUM_SIZE;
161 memcpy(nonce, staticiv, offset);
162 for (loop = 0; loop < SEQ_NUM_SIZE; loop++)
163 nonce[offset + loop] = staticiv[offset + loop] ^ seq[loop];
164
165 if (!tls_increment_sequence_ctr(rl)) {
166 /* RLAYERfatal already called */
167 return 0;
168 }
169
170 /* Set up the AAD */
171 if (!WPACKET_init_static_len(&wpkt, recheader, sizeof(recheader), 0)
172 || !WPACKET_put_bytes_u8(&wpkt, rec->type)
173 || !WPACKET_put_bytes_u16(&wpkt, rec->rec_version)
174 || !WPACKET_put_bytes_u16(&wpkt, rec->length + rl->taglen)
175 || !WPACKET_get_total_written(&wpkt, &hdrlen)
176 || hdrlen != SSL3_RT_HEADER_LENGTH
177 || !WPACKET_finish(&wpkt)) {
178 RLAYERfatal(rl, SSL_AD_INTERNAL_ERROR, ERR_R_INTERNAL_ERROR);
179 WPACKET_cleanup(&wpkt);
180 return 0;
181 }
182
183 if (rl->mac_ctx != NULL) {
184 int ret = 0;
185
186 if ((mac_ctx = EVP_MAC_CTX_dup(rl->mac_ctx)) == NULL
187 || !EVP_MAC_update(mac_ctx, nonce, nonce_len)
188 || !EVP_MAC_update(mac_ctx, recheader, sizeof(recheader))
189 || !EVP_MAC_update(mac_ctx, rec->input, rec->length)
190 || !EVP_MAC_final(mac_ctx, tag, &taglen, rl->taglen)) {
191 RLAYERfatal(rl, SSL_AD_INTERNAL_ERROR, ERR_R_INTERNAL_ERROR);
192 goto end_mac;
193 }
194
195 if (sending) {
196 memcpy(rec->data + rec->length, tag, rl->taglen);
197 rec->length += rl->taglen;
198 } else if (CRYPTO_memcmp(tag, rec->data + rec->length,
199 rl->taglen) != 0) {
200 goto end_mac;
201 }
202 ret = 1;
203 end_mac:
204 EVP_MAC_CTX_free(mac_ctx);
205 return ret;
206 }
207
208 cipher = EVP_CIPHER_CTX_get0_cipher(enc_ctx);
209 if (cipher == NULL) {
210 RLAYERfatal(rl, SSL_AD_INTERNAL_ERROR, ERR_R_INTERNAL_ERROR);
211 return 0;
212 }
213 mode = EVP_CIPHER_get_mode(cipher);
214
215 if (EVP_CipherInit_ex(enc_ctx, NULL, NULL, NULL, nonce, sending) <= 0
216 || (!sending && EVP_CIPHER_CTX_ctrl(enc_ctx, EVP_CTRL_AEAD_SET_TAG,
217 rl->taglen,
218 rec->data + rec->length) <= 0)) {
219 RLAYERfatal(rl, SSL_AD_INTERNAL_ERROR, ERR_R_INTERNAL_ERROR);
220 return 0;
221 }
222
223 /*
224 * For CCM we must explicitly set the total plaintext length before we add
225 * any AAD.
226 */
227 if ((mode == EVP_CIPH_CCM_MODE
228 && EVP_CipherUpdate(enc_ctx, NULL, &lenu, NULL,
229 (unsigned int)rec->length) <= 0)
230 || EVP_CipherUpdate(enc_ctx, NULL, &lenu, recheader,
231 sizeof(recheader)) <= 0
232 || EVP_CipherUpdate(enc_ctx, rec->data, &lenu, rec->input,
233 (unsigned int)rec->length) <= 0
234 || EVP_CipherFinal_ex(enc_ctx, rec->data + lenu, &lenf) <= 0
235 || (size_t)(lenu + lenf) != rec->length) {
236 return 0;
237 }
238 if (sending) {
239 /* Add the tag */
240 if (EVP_CIPHER_CTX_ctrl(enc_ctx, EVP_CTRL_AEAD_GET_TAG, rl->taglen,
241 rec->data + rec->length) <= 0) {
242 RLAYERfatal(rl, SSL_AD_INTERNAL_ERROR, ERR_R_INTERNAL_ERROR);
243 return 0;
244 }
245 rec->length += rl->taglen;
246 }
247
248 return 1;
249 }
250
tls13_validate_record_header(OSSL_RECORD_LAYER * rl,TLS_RL_RECORD * rec)251 static int tls13_validate_record_header(OSSL_RECORD_LAYER *rl,
252 TLS_RL_RECORD *rec)
253 {
254 if (rec->type != SSL3_RT_APPLICATION_DATA
255 && (rec->type != SSL3_RT_CHANGE_CIPHER_SPEC
256 || !rl->is_first_handshake)
257 && (rec->type != SSL3_RT_ALERT || !rl->allow_plain_alerts)) {
258 RLAYERfatal(rl, SSL_AD_UNEXPECTED_MESSAGE, SSL_R_BAD_RECORD_TYPE);
259 return 0;
260 }
261
262 if (rec->rec_version != TLS1_2_VERSION) {
263 RLAYERfatal(rl, SSL_AD_DECODE_ERROR, SSL_R_WRONG_VERSION_NUMBER);
264 return 0;
265 }
266
267 if (rec->length > SSL3_RT_MAX_TLS13_ENCRYPTED_LENGTH) {
268 RLAYERfatal(rl, SSL_AD_RECORD_OVERFLOW,
269 SSL_R_ENCRYPTED_LENGTH_TOO_LONG);
270 return 0;
271 }
272 return 1;
273 }
274
tls13_post_process_record(OSSL_RECORD_LAYER * rl,TLS_RL_RECORD * rec)275 static int tls13_post_process_record(OSSL_RECORD_LAYER *rl, TLS_RL_RECORD *rec)
276 {
277 /* Skip this if we've received a plaintext alert */
278 if (rec->type != SSL3_RT_ALERT) {
279 size_t end;
280
281 if (rec->length == 0
282 || rec->type != SSL3_RT_APPLICATION_DATA) {
283 RLAYERfatal(rl, SSL_AD_UNEXPECTED_MESSAGE,
284 SSL_R_BAD_RECORD_TYPE);
285 return 0;
286 }
287
288 /* Strip trailing padding */
289 for (end = rec->length - 1; end > 0 && rec->data[end] == 0; end--)
290 continue;
291
292 rec->length = end;
293 rec->type = rec->data[end];
294 }
295
296 if (rec->length > SSL3_RT_MAX_PLAIN_LENGTH) {
297 RLAYERfatal(rl, SSL_AD_RECORD_OVERFLOW, SSL_R_DATA_LENGTH_TOO_LONG);
298 return 0;
299 }
300
301 if (!tls13_common_post_process_record(rl, rec)) {
302 /* RLAYERfatal already called */
303 return 0;
304 }
305
306 return 1;
307 }
308
tls13_get_record_type(OSSL_RECORD_LAYER * rl,OSSL_RECORD_TEMPLATE * template)309 static uint8_t tls13_get_record_type(OSSL_RECORD_LAYER *rl,
310 OSSL_RECORD_TEMPLATE *template)
311 {
312 if (rl->allow_plain_alerts && template->type == SSL3_RT_ALERT)
313 return SSL3_RT_ALERT;
314
315 /*
316 * Aside from the above case we always use the application data record type
317 * when encrypting in TLSv1.3. The "inner" record type encodes the "real"
318 * record type from the template.
319 */
320 return SSL3_RT_APPLICATION_DATA;
321 }
322
tls13_add_record_padding(OSSL_RECORD_LAYER * rl,OSSL_RECORD_TEMPLATE * thistempl,WPACKET * thispkt,TLS_RL_RECORD * thiswr)323 static int tls13_add_record_padding(OSSL_RECORD_LAYER *rl,
324 OSSL_RECORD_TEMPLATE *thistempl,
325 WPACKET *thispkt,
326 TLS_RL_RECORD *thiswr)
327 {
328 size_t rlen;
329
330 /* Nothing to be done in the case of a plaintext alert */
331 if (rl->allow_plain_alerts && thistempl->type != SSL3_RT_ALERT)
332 return 1;
333
334 if (!WPACKET_put_bytes_u8(thispkt, thistempl->type)) {
335 RLAYERfatal(rl, SSL_AD_INTERNAL_ERROR, ERR_R_INTERNAL_ERROR);
336 return 0;
337 }
338 TLS_RL_RECORD_add_length(thiswr, 1);
339
340 /* Add TLS1.3 padding */
341 rlen = TLS_RL_RECORD_get_length(thiswr);
342 if (rlen < rl->max_frag_len) {
343 size_t padding = 0;
344 size_t max_padding = rl->max_frag_len - rlen;
345
346 /*
347 * We might want to change the "else if" below so that
348 * library-added padding can still happen even if there
349 * is an application-layer callback. The reason being
350 * the application may not be aware that the effectiveness
351 * of ECH could be damaged if the callback e.g. only
352 * padded application data. However, doing so would be
353 * a change that could break some application that has
354 * a client and server that both know what padding they
355 * like, and that dislike any other padding. That'd need
356 * one of those to have been updated though so the
357 * probability may be low enough that we could change
358 * the "else if" below to just an "if" and pick the
359 * larger of the library and callback's idea of padding.
360 * (Still subject to max_padding though.)
361 */
362 if (rl->padding != NULL) {
363 padding = rl->padding(rl->cbarg, thistempl->type, rlen);
364 } else if (rl->block_padding > 0 || rl->hs_padding > 0) {
365 size_t mask, bp = 0, remainder;
366
367 /*
368 * pad handshake or alert messages based on |hs_padding|
369 * but application data based on |block_padding|
370 */
371 if (thistempl->type == SSL3_RT_HANDSHAKE && rl->hs_padding > 0)
372 bp = rl->hs_padding;
373 else if (thistempl->type == SSL3_RT_ALERT && rl->hs_padding > 0)
374 bp = rl->hs_padding;
375 else if (thistempl->type == SSL3_RT_APPLICATION_DATA
376 && rl->block_padding > 0)
377 bp = rl->block_padding;
378 if (bp > 0) {
379 mask = bp - 1;
380 /* optimize for power of 2 */
381 if ((bp & mask) == 0)
382 remainder = rlen & mask;
383 else
384 remainder = rlen % bp;
385 /* don't want to add a block of padding if we don't have to */
386 if (remainder == 0)
387 padding = 0;
388 else
389 padding = bp - remainder;
390 }
391 }
392 if (padding > 0) {
393 /* do not allow the record to exceed max plaintext length */
394 if (padding > max_padding)
395 padding = max_padding;
396 if (!WPACKET_memset(thispkt, 0, padding)) {
397 RLAYERfatal(rl, SSL_AD_INTERNAL_ERROR,
398 ERR_R_INTERNAL_ERROR);
399 return 0;
400 }
401 TLS_RL_RECORD_add_length(thiswr, padding);
402 }
403 }
404
405 return 1;
406 }
407
408 const struct record_functions_st tls_1_3_funcs = {
409 tls13_set_crypto_state,
410 tls13_cipher,
411 NULL,
412 tls_default_set_protocol_version,
413 tls_default_read_n,
414 tls_get_more_records,
415 tls13_validate_record_header,
416 tls13_post_process_record,
417 tls_get_max_records_default,
418 tls_write_records_default,
419 tls_allocate_write_buffers_default,
420 tls_initialise_write_packets_default,
421 tls13_get_record_type,
422 tls_prepare_record_header_default,
423 tls13_add_record_padding,
424 tls_prepare_for_encryption_default,
425 tls_post_encryption_processing_default,
426 NULL
427 };
428
