xref: /freebsd/crypto/openssl/ssl/t1_enc.c (revision 405c3050f102b8c74782f0366c8ead927bd07b68)
1 /*
2  * Copyright 1995-2018 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_locl.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 tmp1[EVP_MAX_KEY_LENGTH];
85     unsigned char tmp2[EVP_MAX_KEY_LENGTH];
86     unsigned char iv1[EVP_MAX_IV_LENGTH * 2];
87     unsigned char iv2[EVP_MAX_IV_LENGTH * 2];
88     unsigned char *ms, *key, *iv;
89     EVP_CIPHER_CTX *dd;
90     const EVP_CIPHER *c;
91 #ifndef OPENSSL_NO_COMP
92     const SSL_COMP *comp;
93 #endif
94     const EVP_MD *m;
95     int mac_type;
96     size_t *mac_secret_size;
97     EVP_MD_CTX *mac_ctx;
98     EVP_PKEY *mac_key;
99     size_t n, i, j, k, cl;
100     int reuse_dd = 0;
101 
102     c = s->s3->tmp.new_sym_enc;
103     m = s->s3->tmp.new_hash;
104     mac_type = s->s3->tmp.new_mac_pkey_type;
105 #ifndef OPENSSL_NO_COMP
106     comp = s->s3->tmp.new_compression;
107 #endif
108 
109     if (which & SSL3_CC_READ) {
110         if (s->ext.use_etm)
111             s->s3->flags |= TLS1_FLAGS_ENCRYPT_THEN_MAC_READ;
112         else
113             s->s3->flags &= ~TLS1_FLAGS_ENCRYPT_THEN_MAC_READ;
114 
115         if (s->s3->tmp.new_cipher->algorithm2 & TLS1_STREAM_MAC)
116             s->mac_flags |= SSL_MAC_FLAG_READ_MAC_STREAM;
117         else
118             s->mac_flags &= ~SSL_MAC_FLAG_READ_MAC_STREAM;
119 
120         if (s->enc_read_ctx != NULL) {
121             reuse_dd = 1;
122         } else if ((s->enc_read_ctx = EVP_CIPHER_CTX_new()) == NULL) {
123             SSLfatal(s, SSL_AD_INTERNAL_ERROR, SSL_F_TLS1_CHANGE_CIPHER_STATE,
124                      ERR_R_MALLOC_FAILURE);
125             goto err;
126         } else {
127             /*
128              * make sure it's initialised in case we exit later with an error
129              */
130             EVP_CIPHER_CTX_reset(s->enc_read_ctx);
131         }
132         dd = s->enc_read_ctx;
133         mac_ctx = ssl_replace_hash(&s->read_hash, NULL);
134         if (mac_ctx == NULL)
135             goto err;
136 #ifndef OPENSSL_NO_COMP
137         COMP_CTX_free(s->expand);
138         s->expand = NULL;
139         if (comp != NULL) {
140             s->expand = COMP_CTX_new(comp->method);
141             if (s->expand == NULL) {
142                 SSLfatal(s, SSL_AD_INTERNAL_ERROR,
143                          SSL_F_TLS1_CHANGE_CIPHER_STATE,
144                          SSL_R_COMPRESSION_LIBRARY_ERROR);
145                 goto err;
146             }
147         }
148 #endif
149         /*
150          * this is done by dtls1_reset_seq_numbers for DTLS
151          */
152         if (!SSL_IS_DTLS(s))
153             RECORD_LAYER_reset_read_sequence(&s->rlayer);
154         mac_secret = &(s->s3->read_mac_secret[0]);
155         mac_secret_size = &(s->s3->read_mac_secret_size);
156     } else {
157         s->statem.enc_write_state = ENC_WRITE_STATE_INVALID;
158         if (s->ext.use_etm)
159             s->s3->flags |= TLS1_FLAGS_ENCRYPT_THEN_MAC_WRITE;
160         else
161             s->s3->flags &= ~TLS1_FLAGS_ENCRYPT_THEN_MAC_WRITE;
162 
163         if (s->s3->tmp.new_cipher->algorithm2 & TLS1_STREAM_MAC)
164             s->mac_flags |= SSL_MAC_FLAG_WRITE_MAC_STREAM;
165         else
166             s->mac_flags &= ~SSL_MAC_FLAG_WRITE_MAC_STREAM;
167         if (s->enc_write_ctx != NULL && !SSL_IS_DTLS(s)) {
168             reuse_dd = 1;
169         } else if ((s->enc_write_ctx = EVP_CIPHER_CTX_new()) == NULL) {
170             SSLfatal(s, SSL_AD_INTERNAL_ERROR, SSL_F_TLS1_CHANGE_CIPHER_STATE,
171                      ERR_R_MALLOC_FAILURE);
172             goto err;
173         }
174         dd = s->enc_write_ctx;
175         if (SSL_IS_DTLS(s)) {
176             mac_ctx = EVP_MD_CTX_new();
177             if (mac_ctx == NULL) {
178                 SSLfatal(s, SSL_AD_INTERNAL_ERROR,
179                          SSL_F_TLS1_CHANGE_CIPHER_STATE,
180                          ERR_R_MALLOC_FAILURE);
181                 goto err;
182             }
183             s->write_hash = mac_ctx;
184         } else {
185             mac_ctx = ssl_replace_hash(&s->write_hash, NULL);
186             if (mac_ctx == NULL) {
187                 SSLfatal(s, SSL_AD_INTERNAL_ERROR,
188                          SSL_F_TLS1_CHANGE_CIPHER_STATE,
189                          ERR_R_MALLOC_FAILURE);
190                 goto err;
191             }
192         }
193 #ifndef OPENSSL_NO_COMP
194         COMP_CTX_free(s->compress);
195         s->compress = NULL;
196         if (comp != NULL) {
197             s->compress = COMP_CTX_new(comp->method);
198             if (s->compress == NULL) {
199                 SSLfatal(s, SSL_AD_INTERNAL_ERROR,
200                          SSL_F_TLS1_CHANGE_CIPHER_STATE,
201                         SSL_R_COMPRESSION_LIBRARY_ERROR);
202                 goto err;
203             }
204         }
205 #endif
206         /*
207          * this is done by dtls1_reset_seq_numbers for DTLS
208          */
209         if (!SSL_IS_DTLS(s))
210             RECORD_LAYER_reset_write_sequence(&s->rlayer);
211         mac_secret = &(s->s3->write_mac_secret[0]);
212         mac_secret_size = &(s->s3->write_mac_secret_size);
213     }
214 
215     if (reuse_dd)
216         EVP_CIPHER_CTX_reset(dd);
217 
218     p = s->s3->tmp.key_block;
219     i = *mac_secret_size = s->s3->tmp.new_mac_secret_size;
220 
221     /* TODO(size_t): convert me */
222     cl = EVP_CIPHER_key_length(c);
223     j = cl;
224     /* Was j=(exp)?5:EVP_CIPHER_key_length(c); */
225     /* If GCM/CCM mode only part of IV comes from PRF */
226     if (EVP_CIPHER_mode(c) == EVP_CIPH_GCM_MODE)
227         k = EVP_GCM_TLS_FIXED_IV_LEN;
228     else if (EVP_CIPHER_mode(c) == EVP_CIPH_CCM_MODE)
229         k = EVP_CCM_TLS_FIXED_IV_LEN;
230     else
231         k = EVP_CIPHER_iv_length(c);
232     if ((which == SSL3_CHANGE_CIPHER_CLIENT_WRITE) ||
233         (which == SSL3_CHANGE_CIPHER_SERVER_READ)) {
234         ms = &(p[0]);
235         n = i + i;
236         key = &(p[n]);
237         n += j + j;
238         iv = &(p[n]);
239         n += k + k;
240     } else {
241         n = i;
242         ms = &(p[n]);
243         n += i + j;
244         key = &(p[n]);
245         n += j + k;
246         iv = &(p[n]);
247         n += k;
248     }
249 
250     if (n > s->s3->tmp.key_block_length) {
251         SSLfatal(s, SSL_AD_INTERNAL_ERROR, SSL_F_TLS1_CHANGE_CIPHER_STATE,
252                  ERR_R_INTERNAL_ERROR);
253         goto err;
254     }
255 
256     memcpy(mac_secret, ms, i);
257 
258     if (!(EVP_CIPHER_flags(c) & EVP_CIPH_FLAG_AEAD_CIPHER)) {
259         /* TODO(size_t): Convert this function */
260         mac_key = EVP_PKEY_new_mac_key(mac_type, NULL, mac_secret,
261                                                (int)*mac_secret_size);
262         if (mac_key == NULL
263             || EVP_DigestSignInit(mac_ctx, NULL, m, NULL, mac_key) <= 0) {
264             EVP_PKEY_free(mac_key);
265             SSLfatal(s, SSL_AD_INTERNAL_ERROR, SSL_F_TLS1_CHANGE_CIPHER_STATE,
266                      ERR_R_INTERNAL_ERROR);
267             goto err;
268         }
269         EVP_PKEY_free(mac_key);
270     }
271 #ifdef SSL_DEBUG
272     printf("which = %04X\nmac key=", which);
273     {
274         size_t z;
275         for (z = 0; z < i; z++)
276             printf("%02X%c", ms[z], ((z + 1) % 16) ? ' ' : '\n');
277     }
278 #endif
279 
280     if (EVP_CIPHER_mode(c) == EVP_CIPH_GCM_MODE) {
281         if (!EVP_CipherInit_ex(dd, c, NULL, key, NULL, (which & SSL3_CC_WRITE))
282             || !EVP_CIPHER_CTX_ctrl(dd, EVP_CTRL_GCM_SET_IV_FIXED, (int)k,
283                                     iv)) {
284             SSLfatal(s, SSL_AD_INTERNAL_ERROR, SSL_F_TLS1_CHANGE_CIPHER_STATE,
285                      ERR_R_INTERNAL_ERROR);
286             goto err;
287         }
288     } else if (EVP_CIPHER_mode(c) == EVP_CIPH_CCM_MODE) {
289         int taglen;
290         if (s->s3->tmp.
291             new_cipher->algorithm_enc & (SSL_AES128CCM8 | SSL_AES256CCM8))
292             taglen = EVP_CCM8_TLS_TAG_LEN;
293         else
294             taglen = EVP_CCM_TLS_TAG_LEN;
295         if (!EVP_CipherInit_ex(dd, c, NULL, NULL, NULL, (which & SSL3_CC_WRITE))
296             || !EVP_CIPHER_CTX_ctrl(dd, EVP_CTRL_AEAD_SET_IVLEN, 12, NULL)
297             || !EVP_CIPHER_CTX_ctrl(dd, EVP_CTRL_AEAD_SET_TAG, taglen, NULL)
298             || !EVP_CIPHER_CTX_ctrl(dd, EVP_CTRL_CCM_SET_IV_FIXED, (int)k, iv)
299             || !EVP_CipherInit_ex(dd, NULL, NULL, key, NULL, -1)) {
300             SSLfatal(s, SSL_AD_INTERNAL_ERROR, SSL_F_TLS1_CHANGE_CIPHER_STATE,
301                      ERR_R_INTERNAL_ERROR);
302             goto err;
303         }
304     } else {
305         if (!EVP_CipherInit_ex(dd, c, NULL, key, iv, (which & SSL3_CC_WRITE))) {
306             SSLfatal(s, SSL_AD_INTERNAL_ERROR, SSL_F_TLS1_CHANGE_CIPHER_STATE,
307                      ERR_R_INTERNAL_ERROR);
308             goto err;
309         }
310     }
311     /* Needed for "composite" AEADs, such as RC4-HMAC-MD5 */
312     if ((EVP_CIPHER_flags(c) & EVP_CIPH_FLAG_AEAD_CIPHER) && *mac_secret_size
313         && !EVP_CIPHER_CTX_ctrl(dd, EVP_CTRL_AEAD_SET_MAC_KEY,
314                                 (int)*mac_secret_size, mac_secret)) {
315         SSLfatal(s, SSL_AD_INTERNAL_ERROR, SSL_F_TLS1_CHANGE_CIPHER_STATE,
316                  ERR_R_INTERNAL_ERROR);
317         goto err;
318     }
319     s->statem.enc_write_state = ENC_WRITE_STATE_VALID;
320 
321 #ifdef SSL_DEBUG
322     printf("which = %04X\nkey=", which);
323     {
324         int z;
325         for (z = 0; z < EVP_CIPHER_key_length(c); z++)
326             printf("%02X%c", key[z], ((z + 1) % 16) ? ' ' : '\n');
327     }
328     printf("\niv=");
329     {
330         size_t z;
331         for (z = 0; z < k; z++)
332             printf("%02X%c", iv[z], ((z + 1) % 16) ? ' ' : '\n');
333     }
334     printf("\n");
335 #endif
336 
337     OPENSSL_cleanse(tmp1, sizeof(tmp1));
338     OPENSSL_cleanse(tmp2, sizeof(tmp1));
339     OPENSSL_cleanse(iv1, sizeof(iv1));
340     OPENSSL_cleanse(iv2, sizeof(iv2));
341     return 1;
342  err:
343     OPENSSL_cleanse(tmp1, sizeof(tmp1));
344     OPENSSL_cleanse(tmp2, sizeof(tmp1));
345     OPENSSL_cleanse(iv1, sizeof(iv1));
346     OPENSSL_cleanse(iv2, sizeof(iv2));
347     return 0;
348 }
349 
350 int tls1_setup_key_block(SSL *s)
351 {
352     unsigned char *p;
353     const EVP_CIPHER *c;
354     const EVP_MD *hash;
355     SSL_COMP *comp;
356     int mac_type = NID_undef;
357     size_t num, mac_secret_size = 0;
358     int ret = 0;
359 
360     if (s->s3->tmp.key_block_length != 0)
361         return 1;
362 
363     if (!ssl_cipher_get_evp(s->session, &c, &hash, &mac_type, &mac_secret_size,
364                             &comp, s->ext.use_etm)) {
365         SSLfatal(s, SSL_AD_INTERNAL_ERROR, SSL_F_TLS1_SETUP_KEY_BLOCK,
366                  SSL_R_CIPHER_OR_HASH_UNAVAILABLE);
367         return 0;
368     }
369 
370     s->s3->tmp.new_sym_enc = c;
371     s->s3->tmp.new_hash = hash;
372     s->s3->tmp.new_mac_pkey_type = mac_type;
373     s->s3->tmp.new_mac_secret_size = mac_secret_size;
374     num = EVP_CIPHER_key_length(c) + mac_secret_size + EVP_CIPHER_iv_length(c);
375     num *= 2;
376 
377     ssl3_cleanup_key_block(s);
378 
379     if ((p = OPENSSL_malloc(num)) == NULL) {
380         SSLfatal(s, SSL_AD_INTERNAL_ERROR, SSL_F_TLS1_SETUP_KEY_BLOCK,
381                  ERR_R_MALLOC_FAILURE);
382         goto err;
383     }
384 
385     s->s3->tmp.key_block_length = num;
386     s->s3->tmp.key_block = p;
387 
388 #ifdef SSL_DEBUG
389     printf("client random\n");
390     {
391         int z;
392         for (z = 0; z < SSL3_RANDOM_SIZE; z++)
393             printf("%02X%c", s->s3->client_random[z],
394                    ((z + 1) % 16) ? ' ' : '\n');
395     }
396     printf("server random\n");
397     {
398         int z;
399         for (z = 0; z < SSL3_RANDOM_SIZE; z++)
400             printf("%02X%c", s->s3->server_random[z],
401                    ((z + 1) % 16) ? ' ' : '\n');
402     }
403     printf("master key\n");
404     {
405         size_t z;
406         for (z = 0; z < s->session->master_key_length; z++)
407             printf("%02X%c", s->session->master_key[z],
408                    ((z + 1) % 16) ? ' ' : '\n');
409     }
410 #endif
411     if (!tls1_generate_key_block(s, p, num)) {
412         /* SSLfatal() already called */
413         goto err;
414     }
415 #ifdef SSL_DEBUG
416     printf("\nkey block\n");
417     {
418         size_t z;
419         for (z = 0; z < num; z++)
420             printf("%02X%c", p[z], ((z + 1) % 16) ? ' ' : '\n');
421     }
422 #endif
423 
424     if (!(s->options & SSL_OP_DONT_INSERT_EMPTY_FRAGMENTS)
425         && s->method->version <= TLS1_VERSION) {
426         /*
427          * enable vulnerability countermeasure for CBC ciphers with known-IV
428          * problem (http://www.openssl.org/~bodo/tls-cbc.txt)
429          */
430         s->s3->need_empty_fragments = 1;
431 
432         if (s->session->cipher != NULL) {
433             if (s->session->cipher->algorithm_enc == SSL_eNULL)
434                 s->s3->need_empty_fragments = 0;
435 
436 #ifndef OPENSSL_NO_RC4
437             if (s->session->cipher->algorithm_enc == SSL_RC4)
438                 s->s3->need_empty_fragments = 0;
439 #endif
440         }
441     }
442 
443     ret = 1;
444  err:
445     return ret;
446 }
447 
448 size_t tls1_final_finish_mac(SSL *s, const char *str, size_t slen,
449                              unsigned char *out)
450 {
451     size_t hashlen;
452     unsigned char hash[EVP_MAX_MD_SIZE];
453 
454     if (!ssl3_digest_cached_records(s, 0)) {
455         /* SSLfatal() already called */
456         return 0;
457     }
458 
459     if (!ssl_handshake_hash(s, hash, sizeof(hash), &hashlen)) {
460         /* SSLfatal() already called */
461         return 0;
462     }
463 
464     if (!tls1_PRF(s, str, slen, hash, hashlen, NULL, 0, NULL, 0, NULL, 0,
465                   s->session->master_key, s->session->master_key_length,
466                   out, TLS1_FINISH_MAC_LENGTH, 1)) {
467         /* SSLfatal() already called */
468         return 0;
469     }
470     OPENSSL_cleanse(hash, hashlen);
471     return TLS1_FINISH_MAC_LENGTH;
472 }
473 
474 int tls1_generate_master_secret(SSL *s, unsigned char *out, unsigned char *p,
475                                 size_t len, size_t *secret_size)
476 {
477     if (s->session->flags & SSL_SESS_FLAG_EXTMS) {
478         unsigned char hash[EVP_MAX_MD_SIZE * 2];
479         size_t hashlen;
480         /*
481          * Digest cached records keeping record buffer (if present): this wont
482          * affect client auth because we're freezing the buffer at the same
483          * point (after client key exchange and before certificate verify)
484          */
485         if (!ssl3_digest_cached_records(s, 1)
486                 || !ssl_handshake_hash(s, hash, sizeof(hash), &hashlen)) {
487             /* SSLfatal() already called */
488             return 0;
489         }
490 #ifdef SSL_DEBUG
491         fprintf(stderr, "Handshake hashes:\n");
492         BIO_dump_fp(stderr, (char *)hash, hashlen);
493 #endif
494         if (!tls1_PRF(s,
495                       TLS_MD_EXTENDED_MASTER_SECRET_CONST,
496                       TLS_MD_EXTENDED_MASTER_SECRET_CONST_SIZE,
497                       hash, hashlen,
498                       NULL, 0,
499                       NULL, 0,
500                       NULL, 0, p, len, out,
501                       SSL3_MASTER_SECRET_SIZE, 1)) {
502             /* SSLfatal() already called */
503             return 0;
504         }
505         OPENSSL_cleanse(hash, hashlen);
506     } else {
507         if (!tls1_PRF(s,
508                       TLS_MD_MASTER_SECRET_CONST,
509                       TLS_MD_MASTER_SECRET_CONST_SIZE,
510                       s->s3->client_random, SSL3_RANDOM_SIZE,
511                       NULL, 0,
512                       s->s3->server_random, SSL3_RANDOM_SIZE,
513                       NULL, 0, p, len, out,
514                       SSL3_MASTER_SECRET_SIZE, 1)) {
515            /* SSLfatal() already called */
516             return 0;
517         }
518     }
519 #ifdef SSL_DEBUG
520     fprintf(stderr, "Premaster Secret:\n");
521     BIO_dump_fp(stderr, (char *)p, len);
522     fprintf(stderr, "Client Random:\n");
523     BIO_dump_fp(stderr, (char *)s->s3->client_random, SSL3_RANDOM_SIZE);
524     fprintf(stderr, "Server Random:\n");
525     BIO_dump_fp(stderr, (char *)s->s3->server_random, SSL3_RANDOM_SIZE);
526     fprintf(stderr, "Master Secret:\n");
527     BIO_dump_fp(stderr, (char *)s->session->master_key,
528                 SSL3_MASTER_SECRET_SIZE);
529 #endif
530 
531     *secret_size = SSL3_MASTER_SECRET_SIZE;
532     return 1;
533 }
534 
535 int tls1_export_keying_material(SSL *s, unsigned char *out, size_t olen,
536                                 const char *label, size_t llen,
537                                 const unsigned char *context,
538                                 size_t contextlen, int use_context)
539 {
540     unsigned char *val = NULL;
541     size_t vallen = 0, currentvalpos;
542     int rv;
543 
544     /*
545      * construct PRF arguments we construct the PRF argument ourself rather
546      * than passing separate values into the TLS PRF to ensure that the
547      * concatenation of values does not create a prohibited label.
548      */
549     vallen = llen + SSL3_RANDOM_SIZE * 2;
550     if (use_context) {
551         vallen += 2 + contextlen;
552     }
553 
554     val = OPENSSL_malloc(vallen);
555     if (val == NULL)
556         goto err2;
557     currentvalpos = 0;
558     memcpy(val + currentvalpos, (unsigned char *)label, llen);
559     currentvalpos += llen;
560     memcpy(val + currentvalpos, s->s3->client_random, SSL3_RANDOM_SIZE);
561     currentvalpos += SSL3_RANDOM_SIZE;
562     memcpy(val + currentvalpos, s->s3->server_random, SSL3_RANDOM_SIZE);
563     currentvalpos += SSL3_RANDOM_SIZE;
564 
565     if (use_context) {
566         val[currentvalpos] = (contextlen >> 8) & 0xff;
567         currentvalpos++;
568         val[currentvalpos] = contextlen & 0xff;
569         currentvalpos++;
570         if ((contextlen > 0) || (context != NULL)) {
571             memcpy(val + currentvalpos, context, contextlen);
572         }
573     }
574 
575     /*
576      * disallow prohibited labels note that SSL3_RANDOM_SIZE > max(prohibited
577      * label len) = 15, so size of val > max(prohibited label len) = 15 and
578      * the comparisons won't have buffer overflow
579      */
580     if (memcmp(val, TLS_MD_CLIENT_FINISH_CONST,
581                TLS_MD_CLIENT_FINISH_CONST_SIZE) == 0)
582         goto err1;
583     if (memcmp(val, TLS_MD_SERVER_FINISH_CONST,
584                TLS_MD_SERVER_FINISH_CONST_SIZE) == 0)
585         goto err1;
586     if (memcmp(val, TLS_MD_MASTER_SECRET_CONST,
587                TLS_MD_MASTER_SECRET_CONST_SIZE) == 0)
588         goto err1;
589     if (memcmp(val, TLS_MD_EXTENDED_MASTER_SECRET_CONST,
590                TLS_MD_EXTENDED_MASTER_SECRET_CONST_SIZE) == 0)
591         goto err1;
592     if (memcmp(val, TLS_MD_KEY_EXPANSION_CONST,
593                TLS_MD_KEY_EXPANSION_CONST_SIZE) == 0)
594         goto err1;
595 
596     rv = tls1_PRF(s,
597                   val, vallen,
598                   NULL, 0,
599                   NULL, 0,
600                   NULL, 0,
601                   NULL, 0,
602                   s->session->master_key, s->session->master_key_length,
603                   out, olen, 0);
604 
605     goto ret;
606  err1:
607     SSLerr(SSL_F_TLS1_EXPORT_KEYING_MATERIAL, SSL_R_TLS_ILLEGAL_EXPORTER_LABEL);
608     rv = 0;
609     goto ret;
610  err2:
611     SSLerr(SSL_F_TLS1_EXPORT_KEYING_MATERIAL, ERR_R_MALLOC_FAILURE);
612     rv = 0;
613  ret:
614     OPENSSL_clear_free(val, vallen);
615     return rv;
616 }
617 
618 int tls1_alert_code(int code)
619 {
620     switch (code) {
621     case SSL_AD_CLOSE_NOTIFY:
622         return SSL3_AD_CLOSE_NOTIFY;
623     case SSL_AD_UNEXPECTED_MESSAGE:
624         return SSL3_AD_UNEXPECTED_MESSAGE;
625     case SSL_AD_BAD_RECORD_MAC:
626         return SSL3_AD_BAD_RECORD_MAC;
627     case SSL_AD_DECRYPTION_FAILED:
628         return TLS1_AD_DECRYPTION_FAILED;
629     case SSL_AD_RECORD_OVERFLOW:
630         return TLS1_AD_RECORD_OVERFLOW;
631     case SSL_AD_DECOMPRESSION_FAILURE:
632         return SSL3_AD_DECOMPRESSION_FAILURE;
633     case SSL_AD_HANDSHAKE_FAILURE:
634         return SSL3_AD_HANDSHAKE_FAILURE;
635     case SSL_AD_NO_CERTIFICATE:
636         return -1;
637     case SSL_AD_BAD_CERTIFICATE:
638         return SSL3_AD_BAD_CERTIFICATE;
639     case SSL_AD_UNSUPPORTED_CERTIFICATE:
640         return SSL3_AD_UNSUPPORTED_CERTIFICATE;
641     case SSL_AD_CERTIFICATE_REVOKED:
642         return SSL3_AD_CERTIFICATE_REVOKED;
643     case SSL_AD_CERTIFICATE_EXPIRED:
644         return SSL3_AD_CERTIFICATE_EXPIRED;
645     case SSL_AD_CERTIFICATE_UNKNOWN:
646         return SSL3_AD_CERTIFICATE_UNKNOWN;
647     case SSL_AD_ILLEGAL_PARAMETER:
648         return SSL3_AD_ILLEGAL_PARAMETER;
649     case SSL_AD_UNKNOWN_CA:
650         return TLS1_AD_UNKNOWN_CA;
651     case SSL_AD_ACCESS_DENIED:
652         return TLS1_AD_ACCESS_DENIED;
653     case SSL_AD_DECODE_ERROR:
654         return TLS1_AD_DECODE_ERROR;
655     case SSL_AD_DECRYPT_ERROR:
656         return TLS1_AD_DECRYPT_ERROR;
657     case SSL_AD_EXPORT_RESTRICTION:
658         return TLS1_AD_EXPORT_RESTRICTION;
659     case SSL_AD_PROTOCOL_VERSION:
660         return TLS1_AD_PROTOCOL_VERSION;
661     case SSL_AD_INSUFFICIENT_SECURITY:
662         return TLS1_AD_INSUFFICIENT_SECURITY;
663     case SSL_AD_INTERNAL_ERROR:
664         return TLS1_AD_INTERNAL_ERROR;
665     case SSL_AD_USER_CANCELLED:
666         return TLS1_AD_USER_CANCELLED;
667     case SSL_AD_NO_RENEGOTIATION:
668         return TLS1_AD_NO_RENEGOTIATION;
669     case SSL_AD_UNSUPPORTED_EXTENSION:
670         return TLS1_AD_UNSUPPORTED_EXTENSION;
671     case SSL_AD_CERTIFICATE_UNOBTAINABLE:
672         return TLS1_AD_CERTIFICATE_UNOBTAINABLE;
673     case SSL_AD_UNRECOGNIZED_NAME:
674         return TLS1_AD_UNRECOGNIZED_NAME;
675     case SSL_AD_BAD_CERTIFICATE_STATUS_RESPONSE:
676         return TLS1_AD_BAD_CERTIFICATE_STATUS_RESPONSE;
677     case SSL_AD_BAD_CERTIFICATE_HASH_VALUE:
678         return TLS1_AD_BAD_CERTIFICATE_HASH_VALUE;
679     case SSL_AD_UNKNOWN_PSK_IDENTITY:
680         return TLS1_AD_UNKNOWN_PSK_IDENTITY;
681     case SSL_AD_INAPPROPRIATE_FALLBACK:
682         return TLS1_AD_INAPPROPRIATE_FALLBACK;
683     case SSL_AD_NO_APPLICATION_PROTOCOL:
684         return TLS1_AD_NO_APPLICATION_PROTOCOL;
685     case SSL_AD_CERTIFICATE_REQUIRED:
686         return SSL_AD_HANDSHAKE_FAILURE;
687     default:
688         return -1;
689     }
690 }
691