xref: /freebsd/crypto/openssl/ssl/t1_enc.c (revision ce6a89e27cd190313be39bb479880aeda4778436)
1 /*
2  * Copyright 1995-2019 The OpenSSL Project Authors. All Rights Reserved.
3  * Copyright 2005 Nokia. All rights reserved.
4  *
5  * Licensed under the OpenSSL license (the "License").  You may not use
6  * this file except in compliance with the License.  You can obtain a copy
7  * in the file LICENSE in the source distribution or at
8  * https://www.openssl.org/source/license.html
9  */
10 
11 #include <stdio.h>
12 #include "ssl_local.h"
13 #include <openssl/comp.h>
14 #include <openssl/evp.h>
15 #include <openssl/kdf.h>
16 #include <openssl/rand.h>
17 
18 /* seed1 through seed5 are concatenated */
19 static int tls1_PRF(SSL *s,
20                     const void *seed1, size_t seed1_len,
21                     const void *seed2, size_t seed2_len,
22                     const void *seed3, size_t seed3_len,
23                     const void *seed4, size_t seed4_len,
24                     const void *seed5, size_t seed5_len,
25                     const unsigned char *sec, size_t slen,
26                     unsigned char *out, size_t olen, int fatal)
27 {
28     const EVP_MD *md = ssl_prf_md(s);
29     EVP_PKEY_CTX *pctx = NULL;
30     int ret = 0;
31 
32     if (md == NULL) {
33         /* Should never happen */
34         if (fatal)
35             SSLfatal(s, SSL_AD_INTERNAL_ERROR, SSL_F_TLS1_PRF,
36                      ERR_R_INTERNAL_ERROR);
37         else
38             SSLerr(SSL_F_TLS1_PRF, ERR_R_INTERNAL_ERROR);
39         return 0;
40     }
41     pctx = EVP_PKEY_CTX_new_id(EVP_PKEY_TLS1_PRF, NULL);
42     if (pctx == NULL || EVP_PKEY_derive_init(pctx) <= 0
43         || EVP_PKEY_CTX_set_tls1_prf_md(pctx, md) <= 0
44         || EVP_PKEY_CTX_set1_tls1_prf_secret(pctx, sec, (int)slen) <= 0
45         || EVP_PKEY_CTX_add1_tls1_prf_seed(pctx, seed1, (int)seed1_len) <= 0
46         || EVP_PKEY_CTX_add1_tls1_prf_seed(pctx, seed2, (int)seed2_len) <= 0
47         || EVP_PKEY_CTX_add1_tls1_prf_seed(pctx, seed3, (int)seed3_len) <= 0
48         || EVP_PKEY_CTX_add1_tls1_prf_seed(pctx, seed4, (int)seed4_len) <= 0
49         || EVP_PKEY_CTX_add1_tls1_prf_seed(pctx, seed5, (int)seed5_len) <= 0
50         || EVP_PKEY_derive(pctx, out, &olen) <= 0) {
51         if (fatal)
52             SSLfatal(s, SSL_AD_INTERNAL_ERROR, SSL_F_TLS1_PRF,
53                      ERR_R_INTERNAL_ERROR);
54         else
55             SSLerr(SSL_F_TLS1_PRF, ERR_R_INTERNAL_ERROR);
56         goto err;
57     }
58 
59     ret = 1;
60 
61  err:
62     EVP_PKEY_CTX_free(pctx);
63     return ret;
64 }
65 
66 static int tls1_generate_key_block(SSL *s, unsigned char *km, size_t num)
67 {
68     int ret;
69 
70     /* Calls SSLfatal() as required */
71     ret = tls1_PRF(s,
72                    TLS_MD_KEY_EXPANSION_CONST,
73                    TLS_MD_KEY_EXPANSION_CONST_SIZE, s->s3->server_random,
74                    SSL3_RANDOM_SIZE, s->s3->client_random, SSL3_RANDOM_SIZE,
75                    NULL, 0, NULL, 0, s->session->master_key,
76                    s->session->master_key_length, km, num, 1);
77 
78     return ret;
79 }
80 
81 int tls1_change_cipher_state(SSL *s, int which)
82 {
83     unsigned char *p, *mac_secret;
84     unsigned char *ms, *key, *iv;
85     EVP_CIPHER_CTX *dd;
86     const EVP_CIPHER *c;
87 #ifndef OPENSSL_NO_COMP
88     const SSL_COMP *comp;
89 #endif
90     const EVP_MD *m;
91     int mac_type;
92     size_t *mac_secret_size;
93     EVP_MD_CTX *mac_ctx;
94     EVP_PKEY *mac_key;
95     size_t n, i, j, k, cl;
96     int reuse_dd = 0;
97 
98     c = s->s3->tmp.new_sym_enc;
99     m = s->s3->tmp.new_hash;
100     mac_type = s->s3->tmp.new_mac_pkey_type;
101 #ifndef OPENSSL_NO_COMP
102     comp = s->s3->tmp.new_compression;
103 #endif
104 
105     if (which & SSL3_CC_READ) {
106         if (s->ext.use_etm)
107             s->s3->flags |= TLS1_FLAGS_ENCRYPT_THEN_MAC_READ;
108         else
109             s->s3->flags &= ~TLS1_FLAGS_ENCRYPT_THEN_MAC_READ;
110 
111         if (s->s3->tmp.new_cipher->algorithm2 & TLS1_STREAM_MAC)
112             s->mac_flags |= SSL_MAC_FLAG_READ_MAC_STREAM;
113         else
114             s->mac_flags &= ~SSL_MAC_FLAG_READ_MAC_STREAM;
115 
116         if (s->enc_read_ctx != NULL) {
117             reuse_dd = 1;
118         } else if ((s->enc_read_ctx = EVP_CIPHER_CTX_new()) == NULL) {
119             SSLfatal(s, SSL_AD_INTERNAL_ERROR, SSL_F_TLS1_CHANGE_CIPHER_STATE,
120                      ERR_R_MALLOC_FAILURE);
121             goto err;
122         } else {
123             /*
124              * make sure it's initialised in case we exit later with an error
125              */
126             EVP_CIPHER_CTX_reset(s->enc_read_ctx);
127         }
128         dd = s->enc_read_ctx;
129         mac_ctx = ssl_replace_hash(&s->read_hash, NULL);
130         if (mac_ctx == NULL)
131             goto err;
132 #ifndef OPENSSL_NO_COMP
133         COMP_CTX_free(s->expand);
134         s->expand = NULL;
135         if (comp != NULL) {
136             s->expand = COMP_CTX_new(comp->method);
137             if (s->expand == NULL) {
138                 SSLfatal(s, SSL_AD_INTERNAL_ERROR,
139                          SSL_F_TLS1_CHANGE_CIPHER_STATE,
140                          SSL_R_COMPRESSION_LIBRARY_ERROR);
141                 goto err;
142             }
143         }
144 #endif
145         /*
146          * this is done by dtls1_reset_seq_numbers for DTLS
147          */
148         if (!SSL_IS_DTLS(s))
149             RECORD_LAYER_reset_read_sequence(&s->rlayer);
150         mac_secret = &(s->s3->read_mac_secret[0]);
151         mac_secret_size = &(s->s3->read_mac_secret_size);
152     } else {
153         s->statem.enc_write_state = ENC_WRITE_STATE_INVALID;
154         if (s->ext.use_etm)
155             s->s3->flags |= TLS1_FLAGS_ENCRYPT_THEN_MAC_WRITE;
156         else
157             s->s3->flags &= ~TLS1_FLAGS_ENCRYPT_THEN_MAC_WRITE;
158 
159         if (s->s3->tmp.new_cipher->algorithm2 & TLS1_STREAM_MAC)
160             s->mac_flags |= SSL_MAC_FLAG_WRITE_MAC_STREAM;
161         else
162             s->mac_flags &= ~SSL_MAC_FLAG_WRITE_MAC_STREAM;
163         if (s->enc_write_ctx != NULL && !SSL_IS_DTLS(s)) {
164             reuse_dd = 1;
165         } else if ((s->enc_write_ctx = EVP_CIPHER_CTX_new()) == NULL) {
166             SSLfatal(s, SSL_AD_INTERNAL_ERROR, SSL_F_TLS1_CHANGE_CIPHER_STATE,
167                      ERR_R_MALLOC_FAILURE);
168             goto err;
169         }
170         dd = s->enc_write_ctx;
171         if (SSL_IS_DTLS(s)) {
172             mac_ctx = EVP_MD_CTX_new();
173             if (mac_ctx == NULL) {
174                 SSLfatal(s, SSL_AD_INTERNAL_ERROR,
175                          SSL_F_TLS1_CHANGE_CIPHER_STATE,
176                          ERR_R_MALLOC_FAILURE);
177                 goto err;
178             }
179             s->write_hash = mac_ctx;
180         } else {
181             mac_ctx = ssl_replace_hash(&s->write_hash, NULL);
182             if (mac_ctx == NULL) {
183                 SSLfatal(s, SSL_AD_INTERNAL_ERROR,
184                          SSL_F_TLS1_CHANGE_CIPHER_STATE,
185                          ERR_R_MALLOC_FAILURE);
186                 goto err;
187             }
188         }
189 #ifndef OPENSSL_NO_COMP
190         COMP_CTX_free(s->compress);
191         s->compress = NULL;
192         if (comp != NULL) {
193             s->compress = COMP_CTX_new(comp->method);
194             if (s->compress == NULL) {
195                 SSLfatal(s, SSL_AD_INTERNAL_ERROR,
196                          SSL_F_TLS1_CHANGE_CIPHER_STATE,
197                         SSL_R_COMPRESSION_LIBRARY_ERROR);
198                 goto err;
199             }
200         }
201 #endif
202         /*
203          * this is done by dtls1_reset_seq_numbers for DTLS
204          */
205         if (!SSL_IS_DTLS(s))
206             RECORD_LAYER_reset_write_sequence(&s->rlayer);
207         mac_secret = &(s->s3->write_mac_secret[0]);
208         mac_secret_size = &(s->s3->write_mac_secret_size);
209     }
210 
211     if (reuse_dd)
212         EVP_CIPHER_CTX_reset(dd);
213 
214     p = s->s3->tmp.key_block;
215     i = *mac_secret_size = s->s3->tmp.new_mac_secret_size;
216 
217     /* TODO(size_t): convert me */
218     cl = EVP_CIPHER_key_length(c);
219     j = cl;
220     /* Was j=(exp)?5:EVP_CIPHER_key_length(c); */
221     /* If GCM/CCM mode only part of IV comes from PRF */
222     if (EVP_CIPHER_mode(c) == EVP_CIPH_GCM_MODE)
223         k = EVP_GCM_TLS_FIXED_IV_LEN;
224     else if (EVP_CIPHER_mode(c) == EVP_CIPH_CCM_MODE)
225         k = EVP_CCM_TLS_FIXED_IV_LEN;
226     else
227         k = EVP_CIPHER_iv_length(c);
228     if ((which == SSL3_CHANGE_CIPHER_CLIENT_WRITE) ||
229         (which == SSL3_CHANGE_CIPHER_SERVER_READ)) {
230         ms = &(p[0]);
231         n = i + i;
232         key = &(p[n]);
233         n += j + j;
234         iv = &(p[n]);
235         n += k + k;
236     } else {
237         n = i;
238         ms = &(p[n]);
239         n += i + j;
240         key = &(p[n]);
241         n += j + k;
242         iv = &(p[n]);
243         n += k;
244     }
245 
246     if (n > s->s3->tmp.key_block_length) {
247         SSLfatal(s, SSL_AD_INTERNAL_ERROR, SSL_F_TLS1_CHANGE_CIPHER_STATE,
248                  ERR_R_INTERNAL_ERROR);
249         goto err;
250     }
251 
252     memcpy(mac_secret, ms, i);
253 
254     if (!(EVP_CIPHER_flags(c) & EVP_CIPH_FLAG_AEAD_CIPHER)) {
255         /* TODO(size_t): Convert this function */
256         mac_key = EVP_PKEY_new_mac_key(mac_type, NULL, mac_secret,
257                                                (int)*mac_secret_size);
258         if (mac_key == NULL
259             || EVP_DigestSignInit(mac_ctx, NULL, m, NULL, mac_key) <= 0) {
260             EVP_PKEY_free(mac_key);
261             SSLfatal(s, SSL_AD_INTERNAL_ERROR, SSL_F_TLS1_CHANGE_CIPHER_STATE,
262                      ERR_R_INTERNAL_ERROR);
263             goto err;
264         }
265         EVP_PKEY_free(mac_key);
266     }
267 #ifdef SSL_DEBUG
268     printf("which = %04X\nmac key=", which);
269     {
270         size_t z;
271         for (z = 0; z < i; z++)
272             printf("%02X%c", ms[z], ((z + 1) % 16) ? ' ' : '\n');
273     }
274 #endif
275 
276     if (EVP_CIPHER_mode(c) == EVP_CIPH_GCM_MODE) {
277         if (!EVP_CipherInit_ex(dd, c, NULL, key, NULL, (which & SSL3_CC_WRITE))
278             || !EVP_CIPHER_CTX_ctrl(dd, EVP_CTRL_GCM_SET_IV_FIXED, (int)k,
279                                     iv)) {
280             SSLfatal(s, SSL_AD_INTERNAL_ERROR, SSL_F_TLS1_CHANGE_CIPHER_STATE,
281                      ERR_R_INTERNAL_ERROR);
282             goto err;
283         }
284     } else if (EVP_CIPHER_mode(c) == EVP_CIPH_CCM_MODE) {
285         int taglen;
286         if (s->s3->tmp.
287             new_cipher->algorithm_enc & (SSL_AES128CCM8 | SSL_AES256CCM8))
288             taglen = EVP_CCM8_TLS_TAG_LEN;
289         else
290             taglen = EVP_CCM_TLS_TAG_LEN;
291         if (!EVP_CipherInit_ex(dd, c, NULL, NULL, NULL, (which & SSL3_CC_WRITE))
292             || !EVP_CIPHER_CTX_ctrl(dd, EVP_CTRL_AEAD_SET_IVLEN, 12, NULL)
293             || !EVP_CIPHER_CTX_ctrl(dd, EVP_CTRL_AEAD_SET_TAG, taglen, NULL)
294             || !EVP_CIPHER_CTX_ctrl(dd, EVP_CTRL_CCM_SET_IV_FIXED, (int)k, iv)
295             || !EVP_CipherInit_ex(dd, NULL, NULL, key, NULL, -1)) {
296             SSLfatal(s, SSL_AD_INTERNAL_ERROR, SSL_F_TLS1_CHANGE_CIPHER_STATE,
297                      ERR_R_INTERNAL_ERROR);
298             goto err;
299         }
300     } else {
301         if (!EVP_CipherInit_ex(dd, c, NULL, key, iv, (which & SSL3_CC_WRITE))) {
302             SSLfatal(s, SSL_AD_INTERNAL_ERROR, SSL_F_TLS1_CHANGE_CIPHER_STATE,
303                      ERR_R_INTERNAL_ERROR);
304             goto err;
305         }
306     }
307     /* Needed for "composite" AEADs, such as RC4-HMAC-MD5 */
308     if ((EVP_CIPHER_flags(c) & EVP_CIPH_FLAG_AEAD_CIPHER) && *mac_secret_size
309         && !EVP_CIPHER_CTX_ctrl(dd, EVP_CTRL_AEAD_SET_MAC_KEY,
310                                 (int)*mac_secret_size, mac_secret)) {
311         SSLfatal(s, SSL_AD_INTERNAL_ERROR, SSL_F_TLS1_CHANGE_CIPHER_STATE,
312                  ERR_R_INTERNAL_ERROR);
313         goto err;
314     }
315     s->statem.enc_write_state = ENC_WRITE_STATE_VALID;
316 
317 #ifdef SSL_DEBUG
318     printf("which = %04X\nkey=", which);
319     {
320         int z;
321         for (z = 0; z < EVP_CIPHER_key_length(c); z++)
322             printf("%02X%c", key[z], ((z + 1) % 16) ? ' ' : '\n');
323     }
324     printf("\niv=");
325     {
326         size_t z;
327         for (z = 0; z < k; z++)
328             printf("%02X%c", iv[z], ((z + 1) % 16) ? ' ' : '\n');
329     }
330     printf("\n");
331 #endif
332 
333     return 1;
334  err:
335     return 0;
336 }
337 
338 int tls1_setup_key_block(SSL *s)
339 {
340     unsigned char *p;
341     const EVP_CIPHER *c;
342     const EVP_MD *hash;
343     SSL_COMP *comp;
344     int mac_type = NID_undef;
345     size_t num, mac_secret_size = 0;
346     int ret = 0;
347 
348     if (s->s3->tmp.key_block_length != 0)
349         return 1;
350 
351     if (!ssl_cipher_get_evp(s->session, &c, &hash, &mac_type, &mac_secret_size,
352                             &comp, s->ext.use_etm)) {
353         SSLfatal(s, SSL_AD_INTERNAL_ERROR, SSL_F_TLS1_SETUP_KEY_BLOCK,
354                  SSL_R_CIPHER_OR_HASH_UNAVAILABLE);
355         return 0;
356     }
357 
358     s->s3->tmp.new_sym_enc = c;
359     s->s3->tmp.new_hash = hash;
360     s->s3->tmp.new_mac_pkey_type = mac_type;
361     s->s3->tmp.new_mac_secret_size = mac_secret_size;
362     num = EVP_CIPHER_key_length(c) + mac_secret_size + EVP_CIPHER_iv_length(c);
363     num *= 2;
364 
365     ssl3_cleanup_key_block(s);
366 
367     if ((p = OPENSSL_malloc(num)) == NULL) {
368         SSLfatal(s, SSL_AD_INTERNAL_ERROR, SSL_F_TLS1_SETUP_KEY_BLOCK,
369                  ERR_R_MALLOC_FAILURE);
370         goto err;
371     }
372 
373     s->s3->tmp.key_block_length = num;
374     s->s3->tmp.key_block = p;
375 
376 #ifdef SSL_DEBUG
377     printf("client random\n");
378     {
379         int z;
380         for (z = 0; z < SSL3_RANDOM_SIZE; z++)
381             printf("%02X%c", s->s3->client_random[z],
382                    ((z + 1) % 16) ? ' ' : '\n');
383     }
384     printf("server random\n");
385     {
386         int z;
387         for (z = 0; z < SSL3_RANDOM_SIZE; z++)
388             printf("%02X%c", s->s3->server_random[z],
389                    ((z + 1) % 16) ? ' ' : '\n');
390     }
391     printf("master key\n");
392     {
393         size_t z;
394         for (z = 0; z < s->session->master_key_length; z++)
395             printf("%02X%c", s->session->master_key[z],
396                    ((z + 1) % 16) ? ' ' : '\n');
397     }
398 #endif
399     if (!tls1_generate_key_block(s, p, num)) {
400         /* SSLfatal() already called */
401         goto err;
402     }
403 #ifdef SSL_DEBUG
404     printf("\nkey block\n");
405     {
406         size_t z;
407         for (z = 0; z < num; z++)
408             printf("%02X%c", p[z], ((z + 1) % 16) ? ' ' : '\n');
409     }
410 #endif
411 
412     if (!(s->options & SSL_OP_DONT_INSERT_EMPTY_FRAGMENTS)
413         && s->method->version <= TLS1_VERSION) {
414         /*
415          * enable vulnerability countermeasure for CBC ciphers with known-IV
416          * problem (http://www.openssl.org/~bodo/tls-cbc.txt)
417          */
418         s->s3->need_empty_fragments = 1;
419 
420         if (s->session->cipher != NULL) {
421             if (s->session->cipher->algorithm_enc == SSL_eNULL)
422                 s->s3->need_empty_fragments = 0;
423 
424 #ifndef OPENSSL_NO_RC4
425             if (s->session->cipher->algorithm_enc == SSL_RC4)
426                 s->s3->need_empty_fragments = 0;
427 #endif
428         }
429     }
430 
431     ret = 1;
432  err:
433     return ret;
434 }
435 
436 size_t tls1_final_finish_mac(SSL *s, const char *str, size_t slen,
437                              unsigned char *out)
438 {
439     size_t hashlen;
440     unsigned char hash[EVP_MAX_MD_SIZE];
441 
442     if (!ssl3_digest_cached_records(s, 0)) {
443         /* SSLfatal() already called */
444         return 0;
445     }
446 
447     if (!ssl_handshake_hash(s, hash, sizeof(hash), &hashlen)) {
448         /* SSLfatal() already called */
449         return 0;
450     }
451 
452     if (!tls1_PRF(s, str, slen, hash, hashlen, NULL, 0, NULL, 0, NULL, 0,
453                   s->session->master_key, s->session->master_key_length,
454                   out, TLS1_FINISH_MAC_LENGTH, 1)) {
455         /* SSLfatal() already called */
456         return 0;
457     }
458     OPENSSL_cleanse(hash, hashlen);
459     return TLS1_FINISH_MAC_LENGTH;
460 }
461 
462 int tls1_generate_master_secret(SSL *s, unsigned char *out, unsigned char *p,
463                                 size_t len, size_t *secret_size)
464 {
465     if (s->session->flags & SSL_SESS_FLAG_EXTMS) {
466         unsigned char hash[EVP_MAX_MD_SIZE * 2];
467         size_t hashlen;
468         /*
469          * Digest cached records keeping record buffer (if present): this won't
470          * affect client auth because we're freezing the buffer at the same
471          * point (after client key exchange and before certificate verify)
472          */
473         if (!ssl3_digest_cached_records(s, 1)
474                 || !ssl_handshake_hash(s, hash, sizeof(hash), &hashlen)) {
475             /* SSLfatal() already called */
476             return 0;
477         }
478 #ifdef SSL_DEBUG
479         fprintf(stderr, "Handshake hashes:\n");
480         BIO_dump_fp(stderr, (char *)hash, hashlen);
481 #endif
482         if (!tls1_PRF(s,
483                       TLS_MD_EXTENDED_MASTER_SECRET_CONST,
484                       TLS_MD_EXTENDED_MASTER_SECRET_CONST_SIZE,
485                       hash, hashlen,
486                       NULL, 0,
487                       NULL, 0,
488                       NULL, 0, p, len, out,
489                       SSL3_MASTER_SECRET_SIZE, 1)) {
490             /* SSLfatal() already called */
491             return 0;
492         }
493         OPENSSL_cleanse(hash, hashlen);
494     } else {
495         if (!tls1_PRF(s,
496                       TLS_MD_MASTER_SECRET_CONST,
497                       TLS_MD_MASTER_SECRET_CONST_SIZE,
498                       s->s3->client_random, SSL3_RANDOM_SIZE,
499                       NULL, 0,
500                       s->s3->server_random, SSL3_RANDOM_SIZE,
501                       NULL, 0, p, len, out,
502                       SSL3_MASTER_SECRET_SIZE, 1)) {
503            /* SSLfatal() already called */
504             return 0;
505         }
506     }
507 #ifdef SSL_DEBUG
508     fprintf(stderr, "Premaster Secret:\n");
509     BIO_dump_fp(stderr, (char *)p, len);
510     fprintf(stderr, "Client Random:\n");
511     BIO_dump_fp(stderr, (char *)s->s3->client_random, SSL3_RANDOM_SIZE);
512     fprintf(stderr, "Server Random:\n");
513     BIO_dump_fp(stderr, (char *)s->s3->server_random, SSL3_RANDOM_SIZE);
514     fprintf(stderr, "Master Secret:\n");
515     BIO_dump_fp(stderr, (char *)s->session->master_key,
516                 SSL3_MASTER_SECRET_SIZE);
517 #endif
518 
519     *secret_size = SSL3_MASTER_SECRET_SIZE;
520     return 1;
521 }
522 
523 int tls1_export_keying_material(SSL *s, unsigned char *out, size_t olen,
524                                 const char *label, size_t llen,
525                                 const unsigned char *context,
526                                 size_t contextlen, int use_context)
527 {
528     unsigned char *val = NULL;
529     size_t vallen = 0, currentvalpos;
530     int rv;
531 
532     /*
533      * construct PRF arguments we construct the PRF argument ourself rather
534      * than passing separate values into the TLS PRF to ensure that the
535      * concatenation of values does not create a prohibited label.
536      */
537     vallen = llen + SSL3_RANDOM_SIZE * 2;
538     if (use_context) {
539         vallen += 2 + contextlen;
540     }
541 
542     val = OPENSSL_malloc(vallen);
543     if (val == NULL)
544         goto err2;
545     currentvalpos = 0;
546     memcpy(val + currentvalpos, (unsigned char *)label, llen);
547     currentvalpos += llen;
548     memcpy(val + currentvalpos, s->s3->client_random, SSL3_RANDOM_SIZE);
549     currentvalpos += SSL3_RANDOM_SIZE;
550     memcpy(val + currentvalpos, s->s3->server_random, SSL3_RANDOM_SIZE);
551     currentvalpos += SSL3_RANDOM_SIZE;
552 
553     if (use_context) {
554         val[currentvalpos] = (contextlen >> 8) & 0xff;
555         currentvalpos++;
556         val[currentvalpos] = contextlen & 0xff;
557         currentvalpos++;
558         if ((contextlen > 0) || (context != NULL)) {
559             memcpy(val + currentvalpos, context, contextlen);
560         }
561     }
562 
563     /*
564      * disallow prohibited labels note that SSL3_RANDOM_SIZE > max(prohibited
565      * label len) = 15, so size of val > max(prohibited label len) = 15 and
566      * the comparisons won't have buffer overflow
567      */
568     if (memcmp(val, TLS_MD_CLIENT_FINISH_CONST,
569                TLS_MD_CLIENT_FINISH_CONST_SIZE) == 0)
570         goto err1;
571     if (memcmp(val, TLS_MD_SERVER_FINISH_CONST,
572                TLS_MD_SERVER_FINISH_CONST_SIZE) == 0)
573         goto err1;
574     if (memcmp(val, TLS_MD_MASTER_SECRET_CONST,
575                TLS_MD_MASTER_SECRET_CONST_SIZE) == 0)
576         goto err1;
577     if (memcmp(val, TLS_MD_EXTENDED_MASTER_SECRET_CONST,
578                TLS_MD_EXTENDED_MASTER_SECRET_CONST_SIZE) == 0)
579         goto err1;
580     if (memcmp(val, TLS_MD_KEY_EXPANSION_CONST,
581                TLS_MD_KEY_EXPANSION_CONST_SIZE) == 0)
582         goto err1;
583 
584     rv = tls1_PRF(s,
585                   val, vallen,
586                   NULL, 0,
587                   NULL, 0,
588                   NULL, 0,
589                   NULL, 0,
590                   s->session->master_key, s->session->master_key_length,
591                   out, olen, 0);
592 
593     goto ret;
594  err1:
595     SSLerr(SSL_F_TLS1_EXPORT_KEYING_MATERIAL, SSL_R_TLS_ILLEGAL_EXPORTER_LABEL);
596     rv = 0;
597     goto ret;
598  err2:
599     SSLerr(SSL_F_TLS1_EXPORT_KEYING_MATERIAL, ERR_R_MALLOC_FAILURE);
600     rv = 0;
601  ret:
602     OPENSSL_clear_free(val, vallen);
603     return rv;
604 }
605 
606 int tls1_alert_code(int code)
607 {
608     switch (code) {
609     case SSL_AD_CLOSE_NOTIFY:
610         return SSL3_AD_CLOSE_NOTIFY;
611     case SSL_AD_UNEXPECTED_MESSAGE:
612         return SSL3_AD_UNEXPECTED_MESSAGE;
613     case SSL_AD_BAD_RECORD_MAC:
614         return SSL3_AD_BAD_RECORD_MAC;
615     case SSL_AD_DECRYPTION_FAILED:
616         return TLS1_AD_DECRYPTION_FAILED;
617     case SSL_AD_RECORD_OVERFLOW:
618         return TLS1_AD_RECORD_OVERFLOW;
619     case SSL_AD_DECOMPRESSION_FAILURE:
620         return SSL3_AD_DECOMPRESSION_FAILURE;
621     case SSL_AD_HANDSHAKE_FAILURE:
622         return SSL3_AD_HANDSHAKE_FAILURE;
623     case SSL_AD_NO_CERTIFICATE:
624         return -1;
625     case SSL_AD_BAD_CERTIFICATE:
626         return SSL3_AD_BAD_CERTIFICATE;
627     case SSL_AD_UNSUPPORTED_CERTIFICATE:
628         return SSL3_AD_UNSUPPORTED_CERTIFICATE;
629     case SSL_AD_CERTIFICATE_REVOKED:
630         return SSL3_AD_CERTIFICATE_REVOKED;
631     case SSL_AD_CERTIFICATE_EXPIRED:
632         return SSL3_AD_CERTIFICATE_EXPIRED;
633     case SSL_AD_CERTIFICATE_UNKNOWN:
634         return SSL3_AD_CERTIFICATE_UNKNOWN;
635     case SSL_AD_ILLEGAL_PARAMETER:
636         return SSL3_AD_ILLEGAL_PARAMETER;
637     case SSL_AD_UNKNOWN_CA:
638         return TLS1_AD_UNKNOWN_CA;
639     case SSL_AD_ACCESS_DENIED:
640         return TLS1_AD_ACCESS_DENIED;
641     case SSL_AD_DECODE_ERROR:
642         return TLS1_AD_DECODE_ERROR;
643     case SSL_AD_DECRYPT_ERROR:
644         return TLS1_AD_DECRYPT_ERROR;
645     case SSL_AD_EXPORT_RESTRICTION:
646         return TLS1_AD_EXPORT_RESTRICTION;
647     case SSL_AD_PROTOCOL_VERSION:
648         return TLS1_AD_PROTOCOL_VERSION;
649     case SSL_AD_INSUFFICIENT_SECURITY:
650         return TLS1_AD_INSUFFICIENT_SECURITY;
651     case SSL_AD_INTERNAL_ERROR:
652         return TLS1_AD_INTERNAL_ERROR;
653     case SSL_AD_USER_CANCELLED:
654         return TLS1_AD_USER_CANCELLED;
655     case SSL_AD_NO_RENEGOTIATION:
656         return TLS1_AD_NO_RENEGOTIATION;
657     case SSL_AD_UNSUPPORTED_EXTENSION:
658         return TLS1_AD_UNSUPPORTED_EXTENSION;
659     case SSL_AD_CERTIFICATE_UNOBTAINABLE:
660         return TLS1_AD_CERTIFICATE_UNOBTAINABLE;
661     case SSL_AD_UNRECOGNIZED_NAME:
662         return TLS1_AD_UNRECOGNIZED_NAME;
663     case SSL_AD_BAD_CERTIFICATE_STATUS_RESPONSE:
664         return TLS1_AD_BAD_CERTIFICATE_STATUS_RESPONSE;
665     case SSL_AD_BAD_CERTIFICATE_HASH_VALUE:
666         return TLS1_AD_BAD_CERTIFICATE_HASH_VALUE;
667     case SSL_AD_UNKNOWN_PSK_IDENTITY:
668         return TLS1_AD_UNKNOWN_PSK_IDENTITY;
669     case SSL_AD_INAPPROPRIATE_FALLBACK:
670         return TLS1_AD_INAPPROPRIATE_FALLBACK;
671     case SSL_AD_NO_APPLICATION_PROTOCOL:
672         return TLS1_AD_NO_APPLICATION_PROTOCOL;
673     case SSL_AD_CERTIFICATE_REQUIRED:
674         return SSL_AD_HANDSHAKE_FAILURE;
675     default:
676         return -1;
677     }
678 }
679