xref: /freebsd/crypto/openssl/ssl/t1_lib.c (revision c66ec88fed842fbaad62c30d510644ceb7bd2d71)
1 /*
2  * Copyright 1995-2020 The OpenSSL Project Authors. All Rights Reserved.
3  *
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
8  */
9 
10 #include <stdio.h>
11 #include <stdlib.h>
12 #include <openssl/objects.h>
13 #include <openssl/evp.h>
14 #include <openssl/hmac.h>
15 #include <openssl/ocsp.h>
16 #include <openssl/conf.h>
17 #include <openssl/x509v3.h>
18 #include <openssl/dh.h>
19 #include <openssl/bn.h>
20 #include "internal/nelem.h"
21 #include "ssl_local.h"
22 #include <openssl/ct.h>
23 
24 static const SIGALG_LOOKUP *find_sig_alg(SSL *s, X509 *x, EVP_PKEY *pkey);
25 static int tls12_sigalg_allowed(const SSL *s, int op, const SIGALG_LOOKUP *lu);
26 
27 SSL3_ENC_METHOD const TLSv1_enc_data = {
28     tls1_enc,
29     tls1_mac,
30     tls1_setup_key_block,
31     tls1_generate_master_secret,
32     tls1_change_cipher_state,
33     tls1_final_finish_mac,
34     TLS_MD_CLIENT_FINISH_CONST, TLS_MD_CLIENT_FINISH_CONST_SIZE,
35     TLS_MD_SERVER_FINISH_CONST, TLS_MD_SERVER_FINISH_CONST_SIZE,
36     tls1_alert_code,
37     tls1_export_keying_material,
38     0,
39     ssl3_set_handshake_header,
40     tls_close_construct_packet,
41     ssl3_handshake_write
42 };
43 
44 SSL3_ENC_METHOD const TLSv1_1_enc_data = {
45     tls1_enc,
46     tls1_mac,
47     tls1_setup_key_block,
48     tls1_generate_master_secret,
49     tls1_change_cipher_state,
50     tls1_final_finish_mac,
51     TLS_MD_CLIENT_FINISH_CONST, TLS_MD_CLIENT_FINISH_CONST_SIZE,
52     TLS_MD_SERVER_FINISH_CONST, TLS_MD_SERVER_FINISH_CONST_SIZE,
53     tls1_alert_code,
54     tls1_export_keying_material,
55     SSL_ENC_FLAG_EXPLICIT_IV,
56     ssl3_set_handshake_header,
57     tls_close_construct_packet,
58     ssl3_handshake_write
59 };
60 
61 SSL3_ENC_METHOD const TLSv1_2_enc_data = {
62     tls1_enc,
63     tls1_mac,
64     tls1_setup_key_block,
65     tls1_generate_master_secret,
66     tls1_change_cipher_state,
67     tls1_final_finish_mac,
68     TLS_MD_CLIENT_FINISH_CONST, TLS_MD_CLIENT_FINISH_CONST_SIZE,
69     TLS_MD_SERVER_FINISH_CONST, TLS_MD_SERVER_FINISH_CONST_SIZE,
70     tls1_alert_code,
71     tls1_export_keying_material,
72     SSL_ENC_FLAG_EXPLICIT_IV | SSL_ENC_FLAG_SIGALGS | SSL_ENC_FLAG_SHA256_PRF
73         | SSL_ENC_FLAG_TLS1_2_CIPHERS,
74     ssl3_set_handshake_header,
75     tls_close_construct_packet,
76     ssl3_handshake_write
77 };
78 
79 SSL3_ENC_METHOD const TLSv1_3_enc_data = {
80     tls13_enc,
81     tls1_mac,
82     tls13_setup_key_block,
83     tls13_generate_master_secret,
84     tls13_change_cipher_state,
85     tls13_final_finish_mac,
86     TLS_MD_CLIENT_FINISH_CONST, TLS_MD_CLIENT_FINISH_CONST_SIZE,
87     TLS_MD_SERVER_FINISH_CONST, TLS_MD_SERVER_FINISH_CONST_SIZE,
88     tls13_alert_code,
89     tls13_export_keying_material,
90     SSL_ENC_FLAG_SIGALGS | SSL_ENC_FLAG_SHA256_PRF,
91     ssl3_set_handshake_header,
92     tls_close_construct_packet,
93     ssl3_handshake_write
94 };
95 
96 long tls1_default_timeout(void)
97 {
98     /*
99      * 2 hours, the 24 hours mentioned in the TLSv1 spec is way too long for
100      * http, the cache would over fill
101      */
102     return (60 * 60 * 2);
103 }
104 
105 int tls1_new(SSL *s)
106 {
107     if (!ssl3_new(s))
108         return 0;
109     if (!s->method->ssl_clear(s))
110         return 0;
111 
112     return 1;
113 }
114 
115 void tls1_free(SSL *s)
116 {
117     OPENSSL_free(s->ext.session_ticket);
118     ssl3_free(s);
119 }
120 
121 int tls1_clear(SSL *s)
122 {
123     if (!ssl3_clear(s))
124         return 0;
125 
126     if (s->method->version == TLS_ANY_VERSION)
127         s->version = TLS_MAX_VERSION;
128     else
129         s->version = s->method->version;
130 
131     return 1;
132 }
133 
134 #ifndef OPENSSL_NO_EC
135 
136 /*
137  * Table of curve information.
138  * Do not delete entries or reorder this array! It is used as a lookup
139  * table: the index of each entry is one less than the TLS curve id.
140  */
141 static const TLS_GROUP_INFO nid_list[] = {
142     {NID_sect163k1, 80, TLS_CURVE_CHAR2}, /* sect163k1 (1) */
143     {NID_sect163r1, 80, TLS_CURVE_CHAR2}, /* sect163r1 (2) */
144     {NID_sect163r2, 80, TLS_CURVE_CHAR2}, /* sect163r2 (3) */
145     {NID_sect193r1, 80, TLS_CURVE_CHAR2}, /* sect193r1 (4) */
146     {NID_sect193r2, 80, TLS_CURVE_CHAR2}, /* sect193r2 (5) */
147     {NID_sect233k1, 112, TLS_CURVE_CHAR2}, /* sect233k1 (6) */
148     {NID_sect233r1, 112, TLS_CURVE_CHAR2}, /* sect233r1 (7) */
149     {NID_sect239k1, 112, TLS_CURVE_CHAR2}, /* sect239k1 (8) */
150     {NID_sect283k1, 128, TLS_CURVE_CHAR2}, /* sect283k1 (9) */
151     {NID_sect283r1, 128, TLS_CURVE_CHAR2}, /* sect283r1 (10) */
152     {NID_sect409k1, 192, TLS_CURVE_CHAR2}, /* sect409k1 (11) */
153     {NID_sect409r1, 192, TLS_CURVE_CHAR2}, /* sect409r1 (12) */
154     {NID_sect571k1, 256, TLS_CURVE_CHAR2}, /* sect571k1 (13) */
155     {NID_sect571r1, 256, TLS_CURVE_CHAR2}, /* sect571r1 (14) */
156     {NID_secp160k1, 80, TLS_CURVE_PRIME}, /* secp160k1 (15) */
157     {NID_secp160r1, 80, TLS_CURVE_PRIME}, /* secp160r1 (16) */
158     {NID_secp160r2, 80, TLS_CURVE_PRIME}, /* secp160r2 (17) */
159     {NID_secp192k1, 80, TLS_CURVE_PRIME}, /* secp192k1 (18) */
160     {NID_X9_62_prime192v1, 80, TLS_CURVE_PRIME}, /* secp192r1 (19) */
161     {NID_secp224k1, 112, TLS_CURVE_PRIME}, /* secp224k1 (20) */
162     {NID_secp224r1, 112, TLS_CURVE_PRIME}, /* secp224r1 (21) */
163     {NID_secp256k1, 128, TLS_CURVE_PRIME}, /* secp256k1 (22) */
164     {NID_X9_62_prime256v1, 128, TLS_CURVE_PRIME}, /* secp256r1 (23) */
165     {NID_secp384r1, 192, TLS_CURVE_PRIME}, /* secp384r1 (24) */
166     {NID_secp521r1, 256, TLS_CURVE_PRIME}, /* secp521r1 (25) */
167     {NID_brainpoolP256r1, 128, TLS_CURVE_PRIME}, /* brainpoolP256r1 (26) */
168     {NID_brainpoolP384r1, 192, TLS_CURVE_PRIME}, /* brainpoolP384r1 (27) */
169     {NID_brainpoolP512r1, 256, TLS_CURVE_PRIME}, /* brainpool512r1 (28) */
170     {EVP_PKEY_X25519, 128, TLS_CURVE_CUSTOM}, /* X25519 (29) */
171     {EVP_PKEY_X448, 224, TLS_CURVE_CUSTOM}, /* X448 (30) */
172 };
173 
174 static const unsigned char ecformats_default[] = {
175     TLSEXT_ECPOINTFORMAT_uncompressed,
176     TLSEXT_ECPOINTFORMAT_ansiX962_compressed_prime,
177     TLSEXT_ECPOINTFORMAT_ansiX962_compressed_char2
178 };
179 
180 /* The default curves */
181 static const uint16_t eccurves_default[] = {
182     29,                      /* X25519 (29) */
183     23,                      /* secp256r1 (23) */
184     30,                      /* X448 (30) */
185     25,                      /* secp521r1 (25) */
186     24,                      /* secp384r1 (24) */
187 };
188 
189 static const uint16_t suiteb_curves[] = {
190     TLSEXT_curve_P_256,
191     TLSEXT_curve_P_384
192 };
193 
194 const TLS_GROUP_INFO *tls1_group_id_lookup(uint16_t group_id)
195 {
196     /* ECC curves from RFC 4492 and RFC 7027 */
197     if (group_id < 1 || group_id > OSSL_NELEM(nid_list))
198         return NULL;
199     return &nid_list[group_id - 1];
200 }
201 
202 static uint16_t tls1_nid2group_id(int nid)
203 {
204     size_t i;
205     for (i = 0; i < OSSL_NELEM(nid_list); i++) {
206         if (nid_list[i].nid == nid)
207             return (uint16_t)(i + 1);
208     }
209     return 0;
210 }
211 
212 /*
213  * Set *pgroups to the supported groups list and *pgroupslen to
214  * the number of groups supported.
215  */
216 void tls1_get_supported_groups(SSL *s, const uint16_t **pgroups,
217                                size_t *pgroupslen)
218 {
219 
220     /* For Suite B mode only include P-256, P-384 */
221     switch (tls1_suiteb(s)) {
222     case SSL_CERT_FLAG_SUITEB_128_LOS:
223         *pgroups = suiteb_curves;
224         *pgroupslen = OSSL_NELEM(suiteb_curves);
225         break;
226 
227     case SSL_CERT_FLAG_SUITEB_128_LOS_ONLY:
228         *pgroups = suiteb_curves;
229         *pgroupslen = 1;
230         break;
231 
232     case SSL_CERT_FLAG_SUITEB_192_LOS:
233         *pgroups = suiteb_curves + 1;
234         *pgroupslen = 1;
235         break;
236 
237     default:
238         if (s->ext.supportedgroups == NULL) {
239             *pgroups = eccurves_default;
240             *pgroupslen = OSSL_NELEM(eccurves_default);
241         } else {
242             *pgroups = s->ext.supportedgroups;
243             *pgroupslen = s->ext.supportedgroups_len;
244         }
245         break;
246     }
247 }
248 
249 /* See if curve is allowed by security callback */
250 int tls_curve_allowed(SSL *s, uint16_t curve, int op)
251 {
252     const TLS_GROUP_INFO *cinfo = tls1_group_id_lookup(curve);
253     unsigned char ctmp[2];
254 
255     if (cinfo == NULL)
256         return 0;
257 # ifdef OPENSSL_NO_EC2M
258     if (cinfo->flags & TLS_CURVE_CHAR2)
259         return 0;
260 # endif
261     ctmp[0] = curve >> 8;
262     ctmp[1] = curve & 0xff;
263     return ssl_security(s, op, cinfo->secbits, cinfo->nid, (void *)ctmp);
264 }
265 
266 /* Return 1 if "id" is in "list" */
267 static int tls1_in_list(uint16_t id, const uint16_t *list, size_t listlen)
268 {
269     size_t i;
270     for (i = 0; i < listlen; i++)
271         if (list[i] == id)
272             return 1;
273     return 0;
274 }
275 
276 /*-
277  * For nmatch >= 0, return the id of the |nmatch|th shared group or 0
278  * if there is no match.
279  * For nmatch == -1, return number of matches
280  * For nmatch == -2, return the id of the group to use for
281  * a tmp key, or 0 if there is no match.
282  */
283 uint16_t tls1_shared_group(SSL *s, int nmatch)
284 {
285     const uint16_t *pref, *supp;
286     size_t num_pref, num_supp, i;
287     int k;
288 
289     /* Can't do anything on client side */
290     if (s->server == 0)
291         return 0;
292     if (nmatch == -2) {
293         if (tls1_suiteb(s)) {
294             /*
295              * For Suite B ciphersuite determines curve: we already know
296              * these are acceptable due to previous checks.
297              */
298             unsigned long cid = s->s3->tmp.new_cipher->id;
299 
300             if (cid == TLS1_CK_ECDHE_ECDSA_WITH_AES_128_GCM_SHA256)
301                 return TLSEXT_curve_P_256;
302             if (cid == TLS1_CK_ECDHE_ECDSA_WITH_AES_256_GCM_SHA384)
303                 return TLSEXT_curve_P_384;
304             /* Should never happen */
305             return 0;
306         }
307         /* If not Suite B just return first preference shared curve */
308         nmatch = 0;
309     }
310     /*
311      * If server preference set, our groups are the preference order
312      * otherwise peer decides.
313      */
314     if (s->options & SSL_OP_CIPHER_SERVER_PREFERENCE) {
315         tls1_get_supported_groups(s, &pref, &num_pref);
316         tls1_get_peer_groups(s, &supp, &num_supp);
317     } else {
318         tls1_get_peer_groups(s, &pref, &num_pref);
319         tls1_get_supported_groups(s, &supp, &num_supp);
320     }
321 
322     for (k = 0, i = 0; i < num_pref; i++) {
323         uint16_t id = pref[i];
324 
325         if (!tls1_in_list(id, supp, num_supp)
326             || !tls_curve_allowed(s, id, SSL_SECOP_CURVE_SHARED))
327                     continue;
328         if (nmatch == k)
329             return id;
330          k++;
331     }
332     if (nmatch == -1)
333         return k;
334     /* Out of range (nmatch > k). */
335     return 0;
336 }
337 
338 int tls1_set_groups(uint16_t **pext, size_t *pextlen,
339                     int *groups, size_t ngroups)
340 {
341     uint16_t *glist;
342     size_t i;
343     /*
344      * Bitmap of groups included to detect duplicates: only works while group
345      * ids < 32
346      */
347     unsigned long dup_list = 0;
348 
349     if (ngroups == 0) {
350         SSLerr(SSL_F_TLS1_SET_GROUPS, SSL_R_BAD_LENGTH);
351         return 0;
352     }
353     if ((glist = OPENSSL_malloc(ngroups * sizeof(*glist))) == NULL) {
354         SSLerr(SSL_F_TLS1_SET_GROUPS, ERR_R_MALLOC_FAILURE);
355         return 0;
356     }
357     for (i = 0; i < ngroups; i++) {
358         unsigned long idmask;
359         uint16_t id;
360         /* TODO(TLS1.3): Convert for DH groups */
361         id = tls1_nid2group_id(groups[i]);
362         idmask = 1L << id;
363         if (!id || (dup_list & idmask)) {
364             OPENSSL_free(glist);
365             return 0;
366         }
367         dup_list |= idmask;
368         glist[i] = id;
369     }
370     OPENSSL_free(*pext);
371     *pext = glist;
372     *pextlen = ngroups;
373     return 1;
374 }
375 
376 # define MAX_CURVELIST   OSSL_NELEM(nid_list)
377 
378 typedef struct {
379     size_t nidcnt;
380     int nid_arr[MAX_CURVELIST];
381 } nid_cb_st;
382 
383 static int nid_cb(const char *elem, int len, void *arg)
384 {
385     nid_cb_st *narg = arg;
386     size_t i;
387     int nid;
388     char etmp[20];
389     if (elem == NULL)
390         return 0;
391     if (narg->nidcnt == MAX_CURVELIST)
392         return 0;
393     if (len > (int)(sizeof(etmp) - 1))
394         return 0;
395     memcpy(etmp, elem, len);
396     etmp[len] = 0;
397     nid = EC_curve_nist2nid(etmp);
398     if (nid == NID_undef)
399         nid = OBJ_sn2nid(etmp);
400     if (nid == NID_undef)
401         nid = OBJ_ln2nid(etmp);
402     if (nid == NID_undef)
403         return 0;
404     for (i = 0; i < narg->nidcnt; i++)
405         if (narg->nid_arr[i] == nid)
406             return 0;
407     narg->nid_arr[narg->nidcnt++] = nid;
408     return 1;
409 }
410 
411 /* Set groups based on a colon separate list */
412 int tls1_set_groups_list(uint16_t **pext, size_t *pextlen, const char *str)
413 {
414     nid_cb_st ncb;
415     ncb.nidcnt = 0;
416     if (!CONF_parse_list(str, ':', 1, nid_cb, &ncb))
417         return 0;
418     if (pext == NULL)
419         return 1;
420     return tls1_set_groups(pext, pextlen, ncb.nid_arr, ncb.nidcnt);
421 }
422 /* Return group id of a key */
423 static uint16_t tls1_get_group_id(EVP_PKEY *pkey)
424 {
425     EC_KEY *ec = EVP_PKEY_get0_EC_KEY(pkey);
426     const EC_GROUP *grp;
427 
428     if (ec == NULL)
429         return 0;
430     grp = EC_KEY_get0_group(ec);
431     return tls1_nid2group_id(EC_GROUP_get_curve_name(grp));
432 }
433 
434 /* Check a key is compatible with compression extension */
435 static int tls1_check_pkey_comp(SSL *s, EVP_PKEY *pkey)
436 {
437     const EC_KEY *ec;
438     const EC_GROUP *grp;
439     unsigned char comp_id;
440     size_t i;
441 
442     /* If not an EC key nothing to check */
443     if (EVP_PKEY_id(pkey) != EVP_PKEY_EC)
444         return 1;
445     ec = EVP_PKEY_get0_EC_KEY(pkey);
446     grp = EC_KEY_get0_group(ec);
447 
448     /* Get required compression id */
449     if (EC_KEY_get_conv_form(ec) == POINT_CONVERSION_UNCOMPRESSED) {
450             comp_id = TLSEXT_ECPOINTFORMAT_uncompressed;
451     } else if (SSL_IS_TLS13(s)) {
452             /*
453              * ec_point_formats extension is not used in TLSv1.3 so we ignore
454              * this check.
455              */
456             return 1;
457     } else {
458         int field_type = EC_METHOD_get_field_type(EC_GROUP_method_of(grp));
459 
460         if (field_type == NID_X9_62_prime_field)
461             comp_id = TLSEXT_ECPOINTFORMAT_ansiX962_compressed_prime;
462         else if (field_type == NID_X9_62_characteristic_two_field)
463             comp_id = TLSEXT_ECPOINTFORMAT_ansiX962_compressed_char2;
464         else
465             return 0;
466     }
467     /*
468      * If point formats extension present check it, otherwise everything is
469      * supported (see RFC4492).
470      */
471     if (s->ext.peer_ecpointformats == NULL)
472         return 1;
473 
474     for (i = 0; i < s->ext.peer_ecpointformats_len; i++) {
475         if (s->ext.peer_ecpointformats[i] == comp_id)
476             return 1;
477     }
478     return 0;
479 }
480 
481 /* Check a group id matches preferences */
482 int tls1_check_group_id(SSL *s, uint16_t group_id, int check_own_groups)
483     {
484     const uint16_t *groups;
485     size_t groups_len;
486 
487     if (group_id == 0)
488         return 0;
489 
490     /* Check for Suite B compliance */
491     if (tls1_suiteb(s) && s->s3->tmp.new_cipher != NULL) {
492         unsigned long cid = s->s3->tmp.new_cipher->id;
493 
494         if (cid == TLS1_CK_ECDHE_ECDSA_WITH_AES_128_GCM_SHA256) {
495             if (group_id != TLSEXT_curve_P_256)
496                 return 0;
497         } else if (cid == TLS1_CK_ECDHE_ECDSA_WITH_AES_256_GCM_SHA384) {
498             if (group_id != TLSEXT_curve_P_384)
499                 return 0;
500         } else {
501             /* Should never happen */
502             return 0;
503         }
504     }
505 
506     if (check_own_groups) {
507         /* Check group is one of our preferences */
508         tls1_get_supported_groups(s, &groups, &groups_len);
509         if (!tls1_in_list(group_id, groups, groups_len))
510             return 0;
511     }
512 
513     if (!tls_curve_allowed(s, group_id, SSL_SECOP_CURVE_CHECK))
514         return 0;
515 
516     /* For clients, nothing more to check */
517     if (!s->server)
518         return 1;
519 
520     /* Check group is one of peers preferences */
521     tls1_get_peer_groups(s, &groups, &groups_len);
522 
523     /*
524      * RFC 4492 does not require the supported elliptic curves extension
525      * so if it is not sent we can just choose any curve.
526      * It is invalid to send an empty list in the supported groups
527      * extension, so groups_len == 0 always means no extension.
528      */
529     if (groups_len == 0)
530             return 1;
531     return tls1_in_list(group_id, groups, groups_len);
532 }
533 
534 void tls1_get_formatlist(SSL *s, const unsigned char **pformats,
535                          size_t *num_formats)
536 {
537     /*
538      * If we have a custom point format list use it otherwise use default
539      */
540     if (s->ext.ecpointformats) {
541         *pformats = s->ext.ecpointformats;
542         *num_formats = s->ext.ecpointformats_len;
543     } else {
544         *pformats = ecformats_default;
545         /* For Suite B we don't support char2 fields */
546         if (tls1_suiteb(s))
547             *num_formats = sizeof(ecformats_default) - 1;
548         else
549             *num_formats = sizeof(ecformats_default);
550     }
551 }
552 
553 /*
554  * Check cert parameters compatible with extensions: currently just checks EC
555  * certificates have compatible curves and compression.
556  */
557 static int tls1_check_cert_param(SSL *s, X509 *x, int check_ee_md)
558 {
559     uint16_t group_id;
560     EVP_PKEY *pkey;
561     pkey = X509_get0_pubkey(x);
562     if (pkey == NULL)
563         return 0;
564     /* If not EC nothing to do */
565     if (EVP_PKEY_id(pkey) != EVP_PKEY_EC)
566         return 1;
567     /* Check compression */
568     if (!tls1_check_pkey_comp(s, pkey))
569         return 0;
570     group_id = tls1_get_group_id(pkey);
571     /*
572      * For a server we allow the certificate to not be in our list of supported
573      * groups.
574      */
575     if (!tls1_check_group_id(s, group_id, !s->server))
576         return 0;
577     /*
578      * Special case for suite B. We *MUST* sign using SHA256+P-256 or
579      * SHA384+P-384.
580      */
581     if (check_ee_md && tls1_suiteb(s)) {
582         int check_md;
583         size_t i;
584 
585         /* Check to see we have necessary signing algorithm */
586         if (group_id == TLSEXT_curve_P_256)
587             check_md = NID_ecdsa_with_SHA256;
588         else if (group_id == TLSEXT_curve_P_384)
589             check_md = NID_ecdsa_with_SHA384;
590         else
591             return 0;           /* Should never happen */
592         for (i = 0; i < s->shared_sigalgslen; i++) {
593             if (check_md == s->shared_sigalgs[i]->sigandhash)
594                 return 1;;
595         }
596         return 0;
597     }
598     return 1;
599 }
600 
601 /*
602  * tls1_check_ec_tmp_key - Check EC temporary key compatibility
603  * @s: SSL connection
604  * @cid: Cipher ID we're considering using
605  *
606  * Checks that the kECDHE cipher suite we're considering using
607  * is compatible with the client extensions.
608  *
609  * Returns 0 when the cipher can't be used or 1 when it can.
610  */
611 int tls1_check_ec_tmp_key(SSL *s, unsigned long cid)
612 {
613     /* If not Suite B just need a shared group */
614     if (!tls1_suiteb(s))
615         return tls1_shared_group(s, 0) != 0;
616     /*
617      * If Suite B, AES128 MUST use P-256 and AES256 MUST use P-384, no other
618      * curves permitted.
619      */
620     if (cid == TLS1_CK_ECDHE_ECDSA_WITH_AES_128_GCM_SHA256)
621         return tls1_check_group_id(s, TLSEXT_curve_P_256, 1);
622     if (cid == TLS1_CK_ECDHE_ECDSA_WITH_AES_256_GCM_SHA384)
623         return tls1_check_group_id(s, TLSEXT_curve_P_384, 1);
624 
625     return 0;
626 }
627 
628 #else
629 
630 static int tls1_check_cert_param(SSL *s, X509 *x, int set_ee_md)
631 {
632     return 1;
633 }
634 
635 #endif                          /* OPENSSL_NO_EC */
636 
637 /* Default sigalg schemes */
638 static const uint16_t tls12_sigalgs[] = {
639 #ifndef OPENSSL_NO_EC
640     TLSEXT_SIGALG_ecdsa_secp256r1_sha256,
641     TLSEXT_SIGALG_ecdsa_secp384r1_sha384,
642     TLSEXT_SIGALG_ecdsa_secp521r1_sha512,
643     TLSEXT_SIGALG_ed25519,
644     TLSEXT_SIGALG_ed448,
645 #endif
646 
647     TLSEXT_SIGALG_rsa_pss_pss_sha256,
648     TLSEXT_SIGALG_rsa_pss_pss_sha384,
649     TLSEXT_SIGALG_rsa_pss_pss_sha512,
650     TLSEXT_SIGALG_rsa_pss_rsae_sha256,
651     TLSEXT_SIGALG_rsa_pss_rsae_sha384,
652     TLSEXT_SIGALG_rsa_pss_rsae_sha512,
653 
654     TLSEXT_SIGALG_rsa_pkcs1_sha256,
655     TLSEXT_SIGALG_rsa_pkcs1_sha384,
656     TLSEXT_SIGALG_rsa_pkcs1_sha512,
657 
658 #ifndef OPENSSL_NO_EC
659     TLSEXT_SIGALG_ecdsa_sha224,
660     TLSEXT_SIGALG_ecdsa_sha1,
661 #endif
662     TLSEXT_SIGALG_rsa_pkcs1_sha224,
663     TLSEXT_SIGALG_rsa_pkcs1_sha1,
664 #ifndef OPENSSL_NO_DSA
665     TLSEXT_SIGALG_dsa_sha224,
666     TLSEXT_SIGALG_dsa_sha1,
667 
668     TLSEXT_SIGALG_dsa_sha256,
669     TLSEXT_SIGALG_dsa_sha384,
670     TLSEXT_SIGALG_dsa_sha512,
671 #endif
672 #ifndef OPENSSL_NO_GOST
673     TLSEXT_SIGALG_gostr34102012_256_gostr34112012_256,
674     TLSEXT_SIGALG_gostr34102012_512_gostr34112012_512,
675     TLSEXT_SIGALG_gostr34102001_gostr3411,
676 #endif
677 };
678 
679 #ifndef OPENSSL_NO_EC
680 static const uint16_t suiteb_sigalgs[] = {
681     TLSEXT_SIGALG_ecdsa_secp256r1_sha256,
682     TLSEXT_SIGALG_ecdsa_secp384r1_sha384
683 };
684 #endif
685 
686 static const SIGALG_LOOKUP sigalg_lookup_tbl[] = {
687 #ifndef OPENSSL_NO_EC
688     {"ecdsa_secp256r1_sha256", TLSEXT_SIGALG_ecdsa_secp256r1_sha256,
689      NID_sha256, SSL_MD_SHA256_IDX, EVP_PKEY_EC, SSL_PKEY_ECC,
690      NID_ecdsa_with_SHA256, NID_X9_62_prime256v1},
691     {"ecdsa_secp384r1_sha384", TLSEXT_SIGALG_ecdsa_secp384r1_sha384,
692      NID_sha384, SSL_MD_SHA384_IDX, EVP_PKEY_EC, SSL_PKEY_ECC,
693      NID_ecdsa_with_SHA384, NID_secp384r1},
694     {"ecdsa_secp521r1_sha512", TLSEXT_SIGALG_ecdsa_secp521r1_sha512,
695      NID_sha512, SSL_MD_SHA512_IDX, EVP_PKEY_EC, SSL_PKEY_ECC,
696      NID_ecdsa_with_SHA512, NID_secp521r1},
697     {"ed25519", TLSEXT_SIGALG_ed25519,
698      NID_undef, -1, EVP_PKEY_ED25519, SSL_PKEY_ED25519,
699      NID_undef, NID_undef},
700     {"ed448", TLSEXT_SIGALG_ed448,
701      NID_undef, -1, EVP_PKEY_ED448, SSL_PKEY_ED448,
702      NID_undef, NID_undef},
703     {NULL, TLSEXT_SIGALG_ecdsa_sha224,
704      NID_sha224, SSL_MD_SHA224_IDX, EVP_PKEY_EC, SSL_PKEY_ECC,
705      NID_ecdsa_with_SHA224, NID_undef},
706     {NULL, TLSEXT_SIGALG_ecdsa_sha1,
707      NID_sha1, SSL_MD_SHA1_IDX, EVP_PKEY_EC, SSL_PKEY_ECC,
708      NID_ecdsa_with_SHA1, NID_undef},
709 #endif
710     {"rsa_pss_rsae_sha256", TLSEXT_SIGALG_rsa_pss_rsae_sha256,
711      NID_sha256, SSL_MD_SHA256_IDX, EVP_PKEY_RSA_PSS, SSL_PKEY_RSA,
712      NID_undef, NID_undef},
713     {"rsa_pss_rsae_sha384", TLSEXT_SIGALG_rsa_pss_rsae_sha384,
714      NID_sha384, SSL_MD_SHA384_IDX, EVP_PKEY_RSA_PSS, SSL_PKEY_RSA,
715      NID_undef, NID_undef},
716     {"rsa_pss_rsae_sha512", TLSEXT_SIGALG_rsa_pss_rsae_sha512,
717      NID_sha512, SSL_MD_SHA512_IDX, EVP_PKEY_RSA_PSS, SSL_PKEY_RSA,
718      NID_undef, NID_undef},
719     {"rsa_pss_pss_sha256", TLSEXT_SIGALG_rsa_pss_pss_sha256,
720      NID_sha256, SSL_MD_SHA256_IDX, EVP_PKEY_RSA_PSS, SSL_PKEY_RSA_PSS_SIGN,
721      NID_undef, NID_undef},
722     {"rsa_pss_pss_sha384", TLSEXT_SIGALG_rsa_pss_pss_sha384,
723      NID_sha384, SSL_MD_SHA384_IDX, EVP_PKEY_RSA_PSS, SSL_PKEY_RSA_PSS_SIGN,
724      NID_undef, NID_undef},
725     {"rsa_pss_pss_sha512", TLSEXT_SIGALG_rsa_pss_pss_sha512,
726      NID_sha512, SSL_MD_SHA512_IDX, EVP_PKEY_RSA_PSS, SSL_PKEY_RSA_PSS_SIGN,
727      NID_undef, NID_undef},
728     {"rsa_pkcs1_sha256", TLSEXT_SIGALG_rsa_pkcs1_sha256,
729      NID_sha256, SSL_MD_SHA256_IDX, EVP_PKEY_RSA, SSL_PKEY_RSA,
730      NID_sha256WithRSAEncryption, NID_undef},
731     {"rsa_pkcs1_sha384", TLSEXT_SIGALG_rsa_pkcs1_sha384,
732      NID_sha384, SSL_MD_SHA384_IDX, EVP_PKEY_RSA, SSL_PKEY_RSA,
733      NID_sha384WithRSAEncryption, NID_undef},
734     {"rsa_pkcs1_sha512", TLSEXT_SIGALG_rsa_pkcs1_sha512,
735      NID_sha512, SSL_MD_SHA512_IDX, EVP_PKEY_RSA, SSL_PKEY_RSA,
736      NID_sha512WithRSAEncryption, NID_undef},
737     {"rsa_pkcs1_sha224", TLSEXT_SIGALG_rsa_pkcs1_sha224,
738      NID_sha224, SSL_MD_SHA224_IDX, EVP_PKEY_RSA, SSL_PKEY_RSA,
739      NID_sha224WithRSAEncryption, NID_undef},
740     {"rsa_pkcs1_sha1", TLSEXT_SIGALG_rsa_pkcs1_sha1,
741      NID_sha1, SSL_MD_SHA1_IDX, EVP_PKEY_RSA, SSL_PKEY_RSA,
742      NID_sha1WithRSAEncryption, NID_undef},
743 #ifndef OPENSSL_NO_DSA
744     {NULL, TLSEXT_SIGALG_dsa_sha256,
745      NID_sha256, SSL_MD_SHA256_IDX, EVP_PKEY_DSA, SSL_PKEY_DSA_SIGN,
746      NID_dsa_with_SHA256, NID_undef},
747     {NULL, TLSEXT_SIGALG_dsa_sha384,
748      NID_sha384, SSL_MD_SHA384_IDX, EVP_PKEY_DSA, SSL_PKEY_DSA_SIGN,
749      NID_undef, NID_undef},
750     {NULL, TLSEXT_SIGALG_dsa_sha512,
751      NID_sha512, SSL_MD_SHA512_IDX, EVP_PKEY_DSA, SSL_PKEY_DSA_SIGN,
752      NID_undef, NID_undef},
753     {NULL, TLSEXT_SIGALG_dsa_sha224,
754      NID_sha224, SSL_MD_SHA224_IDX, EVP_PKEY_DSA, SSL_PKEY_DSA_SIGN,
755      NID_undef, NID_undef},
756     {NULL, TLSEXT_SIGALG_dsa_sha1,
757      NID_sha1, SSL_MD_SHA1_IDX, EVP_PKEY_DSA, SSL_PKEY_DSA_SIGN,
758      NID_dsaWithSHA1, NID_undef},
759 #endif
760 #ifndef OPENSSL_NO_GOST
761     {NULL, TLSEXT_SIGALG_gostr34102012_256_gostr34112012_256,
762      NID_id_GostR3411_2012_256, SSL_MD_GOST12_256_IDX,
763      NID_id_GostR3410_2012_256, SSL_PKEY_GOST12_256,
764      NID_undef, NID_undef},
765     {NULL, TLSEXT_SIGALG_gostr34102012_512_gostr34112012_512,
766      NID_id_GostR3411_2012_512, SSL_MD_GOST12_512_IDX,
767      NID_id_GostR3410_2012_512, SSL_PKEY_GOST12_512,
768      NID_undef, NID_undef},
769     {NULL, TLSEXT_SIGALG_gostr34102001_gostr3411,
770      NID_id_GostR3411_94, SSL_MD_GOST94_IDX,
771      NID_id_GostR3410_2001, SSL_PKEY_GOST01,
772      NID_undef, NID_undef}
773 #endif
774 };
775 /* Legacy sigalgs for TLS < 1.2 RSA TLS signatures */
776 static const SIGALG_LOOKUP legacy_rsa_sigalg = {
777     "rsa_pkcs1_md5_sha1", 0,
778      NID_md5_sha1, SSL_MD_MD5_SHA1_IDX,
779      EVP_PKEY_RSA, SSL_PKEY_RSA,
780      NID_undef, NID_undef
781 };
782 
783 /*
784  * Default signature algorithm values used if signature algorithms not present.
785  * From RFC5246. Note: order must match certificate index order.
786  */
787 static const uint16_t tls_default_sigalg[] = {
788     TLSEXT_SIGALG_rsa_pkcs1_sha1, /* SSL_PKEY_RSA */
789     0, /* SSL_PKEY_RSA_PSS_SIGN */
790     TLSEXT_SIGALG_dsa_sha1, /* SSL_PKEY_DSA_SIGN */
791     TLSEXT_SIGALG_ecdsa_sha1, /* SSL_PKEY_ECC */
792     TLSEXT_SIGALG_gostr34102001_gostr3411, /* SSL_PKEY_GOST01 */
793     TLSEXT_SIGALG_gostr34102012_256_gostr34112012_256, /* SSL_PKEY_GOST12_256 */
794     TLSEXT_SIGALG_gostr34102012_512_gostr34112012_512, /* SSL_PKEY_GOST12_512 */
795     0, /* SSL_PKEY_ED25519 */
796     0, /* SSL_PKEY_ED448 */
797 };
798 
799 /* Lookup TLS signature algorithm */
800 static const SIGALG_LOOKUP *tls1_lookup_sigalg(uint16_t sigalg)
801 {
802     size_t i;
803     const SIGALG_LOOKUP *s;
804 
805     for (i = 0, s = sigalg_lookup_tbl; i < OSSL_NELEM(sigalg_lookup_tbl);
806          i++, s++) {
807         if (s->sigalg == sigalg)
808             return s;
809     }
810     return NULL;
811 }
812 /* Lookup hash: return 0 if invalid or not enabled */
813 int tls1_lookup_md(const SIGALG_LOOKUP *lu, const EVP_MD **pmd)
814 {
815     const EVP_MD *md;
816     if (lu == NULL)
817         return 0;
818     /* lu->hash == NID_undef means no associated digest */
819     if (lu->hash == NID_undef) {
820         md = NULL;
821     } else {
822         md = ssl_md(lu->hash_idx);
823         if (md == NULL)
824             return 0;
825     }
826     if (pmd)
827         *pmd = md;
828     return 1;
829 }
830 
831 /*
832  * Check if key is large enough to generate RSA-PSS signature.
833  *
834  * The key must greater than or equal to 2 * hash length + 2.
835  * SHA512 has a hash length of 64 bytes, which is incompatible
836  * with a 128 byte (1024 bit) key.
837  */
838 #define RSA_PSS_MINIMUM_KEY_SIZE(md) (2 * EVP_MD_size(md) + 2)
839 static int rsa_pss_check_min_key_size(const RSA *rsa, const SIGALG_LOOKUP *lu)
840 {
841     const EVP_MD *md;
842 
843     if (rsa == NULL)
844         return 0;
845     if (!tls1_lookup_md(lu, &md) || md == NULL)
846         return 0;
847     if (RSA_size(rsa) < RSA_PSS_MINIMUM_KEY_SIZE(md))
848         return 0;
849     return 1;
850 }
851 
852 /*
853  * Returns a signature algorithm when the peer did not send a list of supported
854  * signature algorithms. The signature algorithm is fixed for the certificate
855  * type. |idx| is a certificate type index (SSL_PKEY_*). When |idx| is -1 the
856  * certificate type from |s| will be used.
857  * Returns the signature algorithm to use, or NULL on error.
858  */
859 static const SIGALG_LOOKUP *tls1_get_legacy_sigalg(const SSL *s, int idx)
860 {
861     if (idx == -1) {
862         if (s->server) {
863             size_t i;
864 
865             /* Work out index corresponding to ciphersuite */
866             for (i = 0; i < SSL_PKEY_NUM; i++) {
867                 const SSL_CERT_LOOKUP *clu = ssl_cert_lookup_by_idx(i);
868 
869                 if (clu->amask & s->s3->tmp.new_cipher->algorithm_auth) {
870                     idx = i;
871                     break;
872                 }
873             }
874 
875             /*
876              * Some GOST ciphersuites allow more than one signature algorithms
877              * */
878             if (idx == SSL_PKEY_GOST01 && s->s3->tmp.new_cipher->algorithm_auth != SSL_aGOST01) {
879                 int real_idx;
880 
881                 for (real_idx = SSL_PKEY_GOST12_512; real_idx >= SSL_PKEY_GOST01;
882                      real_idx--) {
883                     if (s->cert->pkeys[real_idx].privatekey != NULL) {
884                         idx = real_idx;
885                         break;
886                     }
887                 }
888             }
889         } else {
890             idx = s->cert->key - s->cert->pkeys;
891         }
892     }
893     if (idx < 0 || idx >= (int)OSSL_NELEM(tls_default_sigalg))
894         return NULL;
895     if (SSL_USE_SIGALGS(s) || idx != SSL_PKEY_RSA) {
896         const SIGALG_LOOKUP *lu = tls1_lookup_sigalg(tls_default_sigalg[idx]);
897 
898         if (!tls1_lookup_md(lu, NULL))
899             return NULL;
900         if (!tls12_sigalg_allowed(s, SSL_SECOP_SIGALG_SUPPORTED, lu))
901             return NULL;
902         return lu;
903     }
904     if (!tls12_sigalg_allowed(s, SSL_SECOP_SIGALG_SUPPORTED, &legacy_rsa_sigalg))
905         return NULL;
906     return &legacy_rsa_sigalg;
907 }
908 /* Set peer sigalg based key type */
909 int tls1_set_peer_legacy_sigalg(SSL *s, const EVP_PKEY *pkey)
910 {
911     size_t idx;
912     const SIGALG_LOOKUP *lu;
913 
914     if (ssl_cert_lookup_by_pkey(pkey, &idx) == NULL)
915         return 0;
916     lu = tls1_get_legacy_sigalg(s, idx);
917     if (lu == NULL)
918         return 0;
919     s->s3->tmp.peer_sigalg = lu;
920     return 1;
921 }
922 
923 size_t tls12_get_psigalgs(SSL *s, int sent, const uint16_t **psigs)
924 {
925     /*
926      * If Suite B mode use Suite B sigalgs only, ignore any other
927      * preferences.
928      */
929 #ifndef OPENSSL_NO_EC
930     switch (tls1_suiteb(s)) {
931     case SSL_CERT_FLAG_SUITEB_128_LOS:
932         *psigs = suiteb_sigalgs;
933         return OSSL_NELEM(suiteb_sigalgs);
934 
935     case SSL_CERT_FLAG_SUITEB_128_LOS_ONLY:
936         *psigs = suiteb_sigalgs;
937         return 1;
938 
939     case SSL_CERT_FLAG_SUITEB_192_LOS:
940         *psigs = suiteb_sigalgs + 1;
941         return 1;
942     }
943 #endif
944     /*
945      *  We use client_sigalgs (if not NULL) if we're a server
946      *  and sending a certificate request or if we're a client and
947      *  determining which shared algorithm to use.
948      */
949     if ((s->server == sent) && s->cert->client_sigalgs != NULL) {
950         *psigs = s->cert->client_sigalgs;
951         return s->cert->client_sigalgslen;
952     } else if (s->cert->conf_sigalgs) {
953         *psigs = s->cert->conf_sigalgs;
954         return s->cert->conf_sigalgslen;
955     } else {
956         *psigs = tls12_sigalgs;
957         return OSSL_NELEM(tls12_sigalgs);
958     }
959 }
960 
961 #ifndef OPENSSL_NO_EC
962 /*
963  * Called by servers only. Checks that we have a sig alg that supports the
964  * specified EC curve.
965  */
966 int tls_check_sigalg_curve(const SSL *s, int curve)
967 {
968    const uint16_t *sigs;
969    size_t siglen, i;
970 
971     if (s->cert->conf_sigalgs) {
972         sigs = s->cert->conf_sigalgs;
973         siglen = s->cert->conf_sigalgslen;
974     } else {
975         sigs = tls12_sigalgs;
976         siglen = OSSL_NELEM(tls12_sigalgs);
977     }
978 
979     for (i = 0; i < siglen; i++) {
980         const SIGALG_LOOKUP *lu = tls1_lookup_sigalg(sigs[i]);
981 
982         if (lu == NULL)
983             continue;
984         if (lu->sig == EVP_PKEY_EC
985                 && lu->curve != NID_undef
986                 && curve == lu->curve)
987             return 1;
988     }
989 
990     return 0;
991 }
992 #endif
993 
994 /*
995  * Return the number of security bits for the signature algorithm, or 0 on
996  * error.
997  */
998 static int sigalg_security_bits(const SIGALG_LOOKUP *lu)
999 {
1000     const EVP_MD *md = NULL;
1001     int secbits = 0;
1002 
1003     if (!tls1_lookup_md(lu, &md))
1004         return 0;
1005     if (md != NULL)
1006     {
1007         /* Security bits: half digest bits */
1008         secbits = EVP_MD_size(md) * 4;
1009     } else {
1010         /* Values from https://tools.ietf.org/html/rfc8032#section-8.5 */
1011         if (lu->sigalg == TLSEXT_SIGALG_ed25519)
1012             secbits = 128;
1013         else if (lu->sigalg == TLSEXT_SIGALG_ed448)
1014             secbits = 224;
1015     }
1016     return secbits;
1017 }
1018 
1019 /*
1020  * Check signature algorithm is consistent with sent supported signature
1021  * algorithms and if so set relevant digest and signature scheme in
1022  * s.
1023  */
1024 int tls12_check_peer_sigalg(SSL *s, uint16_t sig, EVP_PKEY *pkey)
1025 {
1026     const uint16_t *sent_sigs;
1027     const EVP_MD *md = NULL;
1028     char sigalgstr[2];
1029     size_t sent_sigslen, i, cidx;
1030     int pkeyid = EVP_PKEY_id(pkey);
1031     const SIGALG_LOOKUP *lu;
1032     int secbits = 0;
1033 
1034     /* Should never happen */
1035     if (pkeyid == -1)
1036         return -1;
1037     if (SSL_IS_TLS13(s)) {
1038         /* Disallow DSA for TLS 1.3 */
1039         if (pkeyid == EVP_PKEY_DSA) {
1040             SSLfatal(s, SSL_AD_ILLEGAL_PARAMETER, SSL_F_TLS12_CHECK_PEER_SIGALG,
1041                      SSL_R_WRONG_SIGNATURE_TYPE);
1042             return 0;
1043         }
1044         /* Only allow PSS for TLS 1.3 */
1045         if (pkeyid == EVP_PKEY_RSA)
1046             pkeyid = EVP_PKEY_RSA_PSS;
1047     }
1048     lu = tls1_lookup_sigalg(sig);
1049     /*
1050      * Check sigalgs is known. Disallow SHA1/SHA224 with TLS 1.3. Check key type
1051      * is consistent with signature: RSA keys can be used for RSA-PSS
1052      */
1053     if (lu == NULL
1054         || (SSL_IS_TLS13(s) && (lu->hash == NID_sha1 || lu->hash == NID_sha224))
1055         || (pkeyid != lu->sig
1056         && (lu->sig != EVP_PKEY_RSA_PSS || pkeyid != EVP_PKEY_RSA))) {
1057         SSLfatal(s, SSL_AD_ILLEGAL_PARAMETER, SSL_F_TLS12_CHECK_PEER_SIGALG,
1058                  SSL_R_WRONG_SIGNATURE_TYPE);
1059         return 0;
1060     }
1061     /* Check the sigalg is consistent with the key OID */
1062     if (!ssl_cert_lookup_by_nid(EVP_PKEY_id(pkey), &cidx)
1063             || lu->sig_idx != (int)cidx) {
1064         SSLfatal(s, SSL_AD_ILLEGAL_PARAMETER, SSL_F_TLS12_CHECK_PEER_SIGALG,
1065                  SSL_R_WRONG_SIGNATURE_TYPE);
1066         return 0;
1067     }
1068 
1069 #ifndef OPENSSL_NO_EC
1070     if (pkeyid == EVP_PKEY_EC) {
1071 
1072         /* Check point compression is permitted */
1073         if (!tls1_check_pkey_comp(s, pkey)) {
1074             SSLfatal(s, SSL_AD_ILLEGAL_PARAMETER,
1075                      SSL_F_TLS12_CHECK_PEER_SIGALG,
1076                      SSL_R_ILLEGAL_POINT_COMPRESSION);
1077             return 0;
1078         }
1079 
1080         /* For TLS 1.3 or Suite B check curve matches signature algorithm */
1081         if (SSL_IS_TLS13(s) || tls1_suiteb(s)) {
1082             EC_KEY *ec = EVP_PKEY_get0_EC_KEY(pkey);
1083             int curve = EC_GROUP_get_curve_name(EC_KEY_get0_group(ec));
1084 
1085             if (lu->curve != NID_undef && curve != lu->curve) {
1086                 SSLfatal(s, SSL_AD_ILLEGAL_PARAMETER,
1087                          SSL_F_TLS12_CHECK_PEER_SIGALG, SSL_R_WRONG_CURVE);
1088                 return 0;
1089             }
1090         }
1091         if (!SSL_IS_TLS13(s)) {
1092             /* Check curve matches extensions */
1093             if (!tls1_check_group_id(s, tls1_get_group_id(pkey), 1)) {
1094                 SSLfatal(s, SSL_AD_ILLEGAL_PARAMETER,
1095                          SSL_F_TLS12_CHECK_PEER_SIGALG, SSL_R_WRONG_CURVE);
1096                 return 0;
1097             }
1098             if (tls1_suiteb(s)) {
1099                 /* Check sigalg matches a permissible Suite B value */
1100                 if (sig != TLSEXT_SIGALG_ecdsa_secp256r1_sha256
1101                     && sig != TLSEXT_SIGALG_ecdsa_secp384r1_sha384) {
1102                     SSLfatal(s, SSL_AD_HANDSHAKE_FAILURE,
1103                              SSL_F_TLS12_CHECK_PEER_SIGALG,
1104                              SSL_R_WRONG_SIGNATURE_TYPE);
1105                     return 0;
1106                 }
1107             }
1108         }
1109     } else if (tls1_suiteb(s)) {
1110         SSLfatal(s, SSL_AD_HANDSHAKE_FAILURE, SSL_F_TLS12_CHECK_PEER_SIGALG,
1111                  SSL_R_WRONG_SIGNATURE_TYPE);
1112         return 0;
1113     }
1114 #endif
1115 
1116     /* Check signature matches a type we sent */
1117     sent_sigslen = tls12_get_psigalgs(s, 1, &sent_sigs);
1118     for (i = 0; i < sent_sigslen; i++, sent_sigs++) {
1119         if (sig == *sent_sigs)
1120             break;
1121     }
1122     /* Allow fallback to SHA1 if not strict mode */
1123     if (i == sent_sigslen && (lu->hash != NID_sha1
1124         || s->cert->cert_flags & SSL_CERT_FLAGS_CHECK_TLS_STRICT)) {
1125         SSLfatal(s, SSL_AD_HANDSHAKE_FAILURE, SSL_F_TLS12_CHECK_PEER_SIGALG,
1126                  SSL_R_WRONG_SIGNATURE_TYPE);
1127         return 0;
1128     }
1129     if (!tls1_lookup_md(lu, &md)) {
1130         SSLfatal(s, SSL_AD_HANDSHAKE_FAILURE, SSL_F_TLS12_CHECK_PEER_SIGALG,
1131                  SSL_R_UNKNOWN_DIGEST);
1132         return 0;
1133     }
1134     /*
1135      * Make sure security callback allows algorithm. For historical
1136      * reasons we have to pass the sigalg as a two byte char array.
1137      */
1138     sigalgstr[0] = (sig >> 8) & 0xff;
1139     sigalgstr[1] = sig & 0xff;
1140     secbits = sigalg_security_bits(lu);
1141     if (secbits == 0 ||
1142         !ssl_security(s, SSL_SECOP_SIGALG_CHECK, secbits,
1143                       md != NULL ? EVP_MD_type(md) : NID_undef,
1144                       (void *)sigalgstr)) {
1145         SSLfatal(s, SSL_AD_HANDSHAKE_FAILURE, SSL_F_TLS12_CHECK_PEER_SIGALG,
1146                  SSL_R_WRONG_SIGNATURE_TYPE);
1147         return 0;
1148     }
1149     /* Store the sigalg the peer uses */
1150     s->s3->tmp.peer_sigalg = lu;
1151     return 1;
1152 }
1153 
1154 int SSL_get_peer_signature_type_nid(const SSL *s, int *pnid)
1155 {
1156     if (s->s3->tmp.peer_sigalg == NULL)
1157         return 0;
1158     *pnid = s->s3->tmp.peer_sigalg->sig;
1159     return 1;
1160 }
1161 
1162 int SSL_get_signature_type_nid(const SSL *s, int *pnid)
1163 {
1164     if (s->s3->tmp.sigalg == NULL)
1165         return 0;
1166     *pnid = s->s3->tmp.sigalg->sig;
1167     return 1;
1168 }
1169 
1170 /*
1171  * Set a mask of disabled algorithms: an algorithm is disabled if it isn't
1172  * supported, doesn't appear in supported signature algorithms, isn't supported
1173  * by the enabled protocol versions or by the security level.
1174  *
1175  * This function should only be used for checking which ciphers are supported
1176  * by the client.
1177  *
1178  * Call ssl_cipher_disabled() to check that it's enabled or not.
1179  */
1180 int ssl_set_client_disabled(SSL *s)
1181 {
1182     s->s3->tmp.mask_a = 0;
1183     s->s3->tmp.mask_k = 0;
1184     ssl_set_sig_mask(&s->s3->tmp.mask_a, s, SSL_SECOP_SIGALG_MASK);
1185     if (ssl_get_min_max_version(s, &s->s3->tmp.min_ver,
1186                                 &s->s3->tmp.max_ver, NULL) != 0)
1187         return 0;
1188 #ifndef OPENSSL_NO_PSK
1189     /* with PSK there must be client callback set */
1190     if (!s->psk_client_callback) {
1191         s->s3->tmp.mask_a |= SSL_aPSK;
1192         s->s3->tmp.mask_k |= SSL_PSK;
1193     }
1194 #endif                          /* OPENSSL_NO_PSK */
1195 #ifndef OPENSSL_NO_SRP
1196     if (!(s->srp_ctx.srp_Mask & SSL_kSRP)) {
1197         s->s3->tmp.mask_a |= SSL_aSRP;
1198         s->s3->tmp.mask_k |= SSL_kSRP;
1199     }
1200 #endif
1201     return 1;
1202 }
1203 
1204 /*
1205  * ssl_cipher_disabled - check that a cipher is disabled or not
1206  * @s: SSL connection that you want to use the cipher on
1207  * @c: cipher to check
1208  * @op: Security check that you want to do
1209  * @ecdhe: If set to 1 then TLSv1 ECDHE ciphers are also allowed in SSLv3
1210  *
1211  * Returns 1 when it's disabled, 0 when enabled.
1212  */
1213 int ssl_cipher_disabled(const SSL *s, const SSL_CIPHER *c, int op, int ecdhe)
1214 {
1215     if (c->algorithm_mkey & s->s3->tmp.mask_k
1216         || c->algorithm_auth & s->s3->tmp.mask_a)
1217         return 1;
1218     if (s->s3->tmp.max_ver == 0)
1219         return 1;
1220     if (!SSL_IS_DTLS(s)) {
1221         int min_tls = c->min_tls;
1222 
1223         /*
1224          * For historical reasons we will allow ECHDE to be selected by a server
1225          * in SSLv3 if we are a client
1226          */
1227         if (min_tls == TLS1_VERSION && ecdhe
1228                 && (c->algorithm_mkey & (SSL_kECDHE | SSL_kECDHEPSK)) != 0)
1229             min_tls = SSL3_VERSION;
1230 
1231         if ((min_tls > s->s3->tmp.max_ver) || (c->max_tls < s->s3->tmp.min_ver))
1232             return 1;
1233     }
1234     if (SSL_IS_DTLS(s) && (DTLS_VERSION_GT(c->min_dtls, s->s3->tmp.max_ver)
1235                            || DTLS_VERSION_LT(c->max_dtls, s->s3->tmp.min_ver)))
1236         return 1;
1237 
1238     return !ssl_security(s, op, c->strength_bits, 0, (void *)c);
1239 }
1240 
1241 int tls_use_ticket(SSL *s)
1242 {
1243     if ((s->options & SSL_OP_NO_TICKET))
1244         return 0;
1245     return ssl_security(s, SSL_SECOP_TICKET, 0, 0, NULL);
1246 }
1247 
1248 int tls1_set_server_sigalgs(SSL *s)
1249 {
1250     size_t i;
1251 
1252     /* Clear any shared signature algorithms */
1253     OPENSSL_free(s->shared_sigalgs);
1254     s->shared_sigalgs = NULL;
1255     s->shared_sigalgslen = 0;
1256     /* Clear certificate validity flags */
1257     for (i = 0; i < SSL_PKEY_NUM; i++)
1258         s->s3->tmp.valid_flags[i] = 0;
1259     /*
1260      * If peer sent no signature algorithms check to see if we support
1261      * the default algorithm for each certificate type
1262      */
1263     if (s->s3->tmp.peer_cert_sigalgs == NULL
1264             && s->s3->tmp.peer_sigalgs == NULL) {
1265         const uint16_t *sent_sigs;
1266         size_t sent_sigslen = tls12_get_psigalgs(s, 1, &sent_sigs);
1267 
1268         for (i = 0; i < SSL_PKEY_NUM; i++) {
1269             const SIGALG_LOOKUP *lu = tls1_get_legacy_sigalg(s, i);
1270             size_t j;
1271 
1272             if (lu == NULL)
1273                 continue;
1274             /* Check default matches a type we sent */
1275             for (j = 0; j < sent_sigslen; j++) {
1276                 if (lu->sigalg == sent_sigs[j]) {
1277                         s->s3->tmp.valid_flags[i] = CERT_PKEY_SIGN;
1278                         break;
1279                 }
1280             }
1281         }
1282         return 1;
1283     }
1284 
1285     if (!tls1_process_sigalgs(s)) {
1286         SSLfatal(s, SSL_AD_INTERNAL_ERROR,
1287                  SSL_F_TLS1_SET_SERVER_SIGALGS, ERR_R_INTERNAL_ERROR);
1288         return 0;
1289     }
1290     if (s->shared_sigalgs != NULL)
1291         return 1;
1292 
1293     /* Fatal error if no shared signature algorithms */
1294     SSLfatal(s, SSL_AD_HANDSHAKE_FAILURE, SSL_F_TLS1_SET_SERVER_SIGALGS,
1295              SSL_R_NO_SHARED_SIGNATURE_ALGORITHMS);
1296     return 0;
1297 }
1298 
1299 /*-
1300  * Gets the ticket information supplied by the client if any.
1301  *
1302  *   hello: The parsed ClientHello data
1303  *   ret: (output) on return, if a ticket was decrypted, then this is set to
1304  *       point to the resulting session.
1305  */
1306 SSL_TICKET_STATUS tls_get_ticket_from_client(SSL *s, CLIENTHELLO_MSG *hello,
1307                                              SSL_SESSION **ret)
1308 {
1309     size_t size;
1310     RAW_EXTENSION *ticketext;
1311 
1312     *ret = NULL;
1313     s->ext.ticket_expected = 0;
1314 
1315     /*
1316      * If tickets disabled or not supported by the protocol version
1317      * (e.g. TLSv1.3) behave as if no ticket present to permit stateful
1318      * resumption.
1319      */
1320     if (s->version <= SSL3_VERSION || !tls_use_ticket(s))
1321         return SSL_TICKET_NONE;
1322 
1323     ticketext = &hello->pre_proc_exts[TLSEXT_IDX_session_ticket];
1324     if (!ticketext->present)
1325         return SSL_TICKET_NONE;
1326 
1327     size = PACKET_remaining(&ticketext->data);
1328 
1329     return tls_decrypt_ticket(s, PACKET_data(&ticketext->data), size,
1330                               hello->session_id, hello->session_id_len, ret);
1331 }
1332 
1333 /*-
1334  * tls_decrypt_ticket attempts to decrypt a session ticket.
1335  *
1336  * If s->tls_session_secret_cb is set and we're not doing TLSv1.3 then we are
1337  * expecting a pre-shared key ciphersuite, in which case we have no use for
1338  * session tickets and one will never be decrypted, nor will
1339  * s->ext.ticket_expected be set to 1.
1340  *
1341  * Side effects:
1342  *   Sets s->ext.ticket_expected to 1 if the server will have to issue
1343  *   a new session ticket to the client because the client indicated support
1344  *   (and s->tls_session_secret_cb is NULL) but the client either doesn't have
1345  *   a session ticket or we couldn't use the one it gave us, or if
1346  *   s->ctx->ext.ticket_key_cb asked to renew the client's ticket.
1347  *   Otherwise, s->ext.ticket_expected is set to 0.
1348  *
1349  *   etick: points to the body of the session ticket extension.
1350  *   eticklen: the length of the session tickets extension.
1351  *   sess_id: points at the session ID.
1352  *   sesslen: the length of the session ID.
1353  *   psess: (output) on return, if a ticket was decrypted, then this is set to
1354  *       point to the resulting session.
1355  */
1356 SSL_TICKET_STATUS tls_decrypt_ticket(SSL *s, const unsigned char *etick,
1357                                      size_t eticklen, const unsigned char *sess_id,
1358                                      size_t sesslen, SSL_SESSION **psess)
1359 {
1360     SSL_SESSION *sess = NULL;
1361     unsigned char *sdec;
1362     const unsigned char *p;
1363     int slen, renew_ticket = 0, declen;
1364     SSL_TICKET_STATUS ret = SSL_TICKET_FATAL_ERR_OTHER;
1365     size_t mlen;
1366     unsigned char tick_hmac[EVP_MAX_MD_SIZE];
1367     HMAC_CTX *hctx = NULL;
1368     EVP_CIPHER_CTX *ctx = NULL;
1369     SSL_CTX *tctx = s->session_ctx;
1370 
1371     if (eticklen == 0) {
1372         /*
1373          * The client will accept a ticket but doesn't currently have
1374          * one (TLSv1.2 and below), or treated as a fatal error in TLSv1.3
1375          */
1376         ret = SSL_TICKET_EMPTY;
1377         goto end;
1378     }
1379     if (!SSL_IS_TLS13(s) && s->ext.session_secret_cb) {
1380         /*
1381          * Indicate that the ticket couldn't be decrypted rather than
1382          * generating the session from ticket now, trigger
1383          * abbreviated handshake based on external mechanism to
1384          * calculate the master secret later.
1385          */
1386         ret = SSL_TICKET_NO_DECRYPT;
1387         goto end;
1388     }
1389 
1390     /* Need at least keyname + iv */
1391     if (eticklen < TLSEXT_KEYNAME_LENGTH + EVP_MAX_IV_LENGTH) {
1392         ret = SSL_TICKET_NO_DECRYPT;
1393         goto end;
1394     }
1395 
1396     /* Initialize session ticket encryption and HMAC contexts */
1397     hctx = HMAC_CTX_new();
1398     if (hctx == NULL) {
1399         ret = SSL_TICKET_FATAL_ERR_MALLOC;
1400         goto end;
1401     }
1402     ctx = EVP_CIPHER_CTX_new();
1403     if (ctx == NULL) {
1404         ret = SSL_TICKET_FATAL_ERR_MALLOC;
1405         goto end;
1406     }
1407     if (tctx->ext.ticket_key_cb) {
1408         unsigned char *nctick = (unsigned char *)etick;
1409         int rv = tctx->ext.ticket_key_cb(s, nctick,
1410                                          nctick + TLSEXT_KEYNAME_LENGTH,
1411                                          ctx, hctx, 0);
1412         if (rv < 0) {
1413             ret = SSL_TICKET_FATAL_ERR_OTHER;
1414             goto end;
1415         }
1416         if (rv == 0) {
1417             ret = SSL_TICKET_NO_DECRYPT;
1418             goto end;
1419         }
1420         if (rv == 2)
1421             renew_ticket = 1;
1422     } else {
1423         /* Check key name matches */
1424         if (memcmp(etick, tctx->ext.tick_key_name,
1425                    TLSEXT_KEYNAME_LENGTH) != 0) {
1426             ret = SSL_TICKET_NO_DECRYPT;
1427             goto end;
1428         }
1429         if (HMAC_Init_ex(hctx, tctx->ext.secure->tick_hmac_key,
1430                          sizeof(tctx->ext.secure->tick_hmac_key),
1431                          EVP_sha256(), NULL) <= 0
1432             || EVP_DecryptInit_ex(ctx, EVP_aes_256_cbc(), NULL,
1433                                   tctx->ext.secure->tick_aes_key,
1434                                   etick + TLSEXT_KEYNAME_LENGTH) <= 0) {
1435             ret = SSL_TICKET_FATAL_ERR_OTHER;
1436             goto end;
1437         }
1438         if (SSL_IS_TLS13(s))
1439             renew_ticket = 1;
1440     }
1441     /*
1442      * Attempt to process session ticket, first conduct sanity and integrity
1443      * checks on ticket.
1444      */
1445     mlen = HMAC_size(hctx);
1446     if (mlen == 0) {
1447         ret = SSL_TICKET_FATAL_ERR_OTHER;
1448         goto end;
1449     }
1450 
1451     /* Sanity check ticket length: must exceed keyname + IV + HMAC */
1452     if (eticklen <=
1453         TLSEXT_KEYNAME_LENGTH + EVP_CIPHER_CTX_iv_length(ctx) + mlen) {
1454         ret = SSL_TICKET_NO_DECRYPT;
1455         goto end;
1456     }
1457     eticklen -= mlen;
1458     /* Check HMAC of encrypted ticket */
1459     if (HMAC_Update(hctx, etick, eticklen) <= 0
1460         || HMAC_Final(hctx, tick_hmac, NULL) <= 0) {
1461         ret = SSL_TICKET_FATAL_ERR_OTHER;
1462         goto end;
1463     }
1464 
1465     if (CRYPTO_memcmp(tick_hmac, etick + eticklen, mlen)) {
1466         ret = SSL_TICKET_NO_DECRYPT;
1467         goto end;
1468     }
1469     /* Attempt to decrypt session data */
1470     /* Move p after IV to start of encrypted ticket, update length */
1471     p = etick + TLSEXT_KEYNAME_LENGTH + EVP_CIPHER_CTX_iv_length(ctx);
1472     eticklen -= TLSEXT_KEYNAME_LENGTH + EVP_CIPHER_CTX_iv_length(ctx);
1473     sdec = OPENSSL_malloc(eticklen);
1474     if (sdec == NULL || EVP_DecryptUpdate(ctx, sdec, &slen, p,
1475                                           (int)eticklen) <= 0) {
1476         OPENSSL_free(sdec);
1477         ret = SSL_TICKET_FATAL_ERR_OTHER;
1478         goto end;
1479     }
1480     if (EVP_DecryptFinal(ctx, sdec + slen, &declen) <= 0) {
1481         OPENSSL_free(sdec);
1482         ret = SSL_TICKET_NO_DECRYPT;
1483         goto end;
1484     }
1485     slen += declen;
1486     p = sdec;
1487 
1488     sess = d2i_SSL_SESSION(NULL, &p, slen);
1489     slen -= p - sdec;
1490     OPENSSL_free(sdec);
1491     if (sess) {
1492         /* Some additional consistency checks */
1493         if (slen != 0) {
1494             SSL_SESSION_free(sess);
1495             sess = NULL;
1496             ret = SSL_TICKET_NO_DECRYPT;
1497             goto end;
1498         }
1499         /*
1500          * The session ID, if non-empty, is used by some clients to detect
1501          * that the ticket has been accepted. So we copy it to the session
1502          * structure. If it is empty set length to zero as required by
1503          * standard.
1504          */
1505         if (sesslen) {
1506             memcpy(sess->session_id, sess_id, sesslen);
1507             sess->session_id_length = sesslen;
1508         }
1509         if (renew_ticket)
1510             ret = SSL_TICKET_SUCCESS_RENEW;
1511         else
1512             ret = SSL_TICKET_SUCCESS;
1513         goto end;
1514     }
1515     ERR_clear_error();
1516     /*
1517      * For session parse failure, indicate that we need to send a new ticket.
1518      */
1519     ret = SSL_TICKET_NO_DECRYPT;
1520 
1521  end:
1522     EVP_CIPHER_CTX_free(ctx);
1523     HMAC_CTX_free(hctx);
1524 
1525     /*
1526      * If set, the decrypt_ticket_cb() is called unless a fatal error was
1527      * detected above. The callback is responsible for checking |ret| before it
1528      * performs any action
1529      */
1530     if (s->session_ctx->decrypt_ticket_cb != NULL
1531             && (ret == SSL_TICKET_EMPTY
1532                 || ret == SSL_TICKET_NO_DECRYPT
1533                 || ret == SSL_TICKET_SUCCESS
1534                 || ret == SSL_TICKET_SUCCESS_RENEW)) {
1535         size_t keyname_len = eticklen;
1536         int retcb;
1537 
1538         if (keyname_len > TLSEXT_KEYNAME_LENGTH)
1539             keyname_len = TLSEXT_KEYNAME_LENGTH;
1540         retcb = s->session_ctx->decrypt_ticket_cb(s, sess, etick, keyname_len,
1541                                                   ret,
1542                                                   s->session_ctx->ticket_cb_data);
1543         switch (retcb) {
1544         case SSL_TICKET_RETURN_ABORT:
1545             ret = SSL_TICKET_FATAL_ERR_OTHER;
1546             break;
1547 
1548         case SSL_TICKET_RETURN_IGNORE:
1549             ret = SSL_TICKET_NONE;
1550             SSL_SESSION_free(sess);
1551             sess = NULL;
1552             break;
1553 
1554         case SSL_TICKET_RETURN_IGNORE_RENEW:
1555             if (ret != SSL_TICKET_EMPTY && ret != SSL_TICKET_NO_DECRYPT)
1556                 ret = SSL_TICKET_NO_DECRYPT;
1557             /* else the value of |ret| will already do the right thing */
1558             SSL_SESSION_free(sess);
1559             sess = NULL;
1560             break;
1561 
1562         case SSL_TICKET_RETURN_USE:
1563         case SSL_TICKET_RETURN_USE_RENEW:
1564             if (ret != SSL_TICKET_SUCCESS
1565                     && ret != SSL_TICKET_SUCCESS_RENEW)
1566                 ret = SSL_TICKET_FATAL_ERR_OTHER;
1567             else if (retcb == SSL_TICKET_RETURN_USE)
1568                 ret = SSL_TICKET_SUCCESS;
1569             else
1570                 ret = SSL_TICKET_SUCCESS_RENEW;
1571             break;
1572 
1573         default:
1574             ret = SSL_TICKET_FATAL_ERR_OTHER;
1575         }
1576     }
1577 
1578     if (s->ext.session_secret_cb == NULL || SSL_IS_TLS13(s)) {
1579         switch (ret) {
1580         case SSL_TICKET_NO_DECRYPT:
1581         case SSL_TICKET_SUCCESS_RENEW:
1582         case SSL_TICKET_EMPTY:
1583             s->ext.ticket_expected = 1;
1584         }
1585     }
1586 
1587     *psess = sess;
1588 
1589     return ret;
1590 }
1591 
1592 /* Check to see if a signature algorithm is allowed */
1593 static int tls12_sigalg_allowed(const SSL *s, int op, const SIGALG_LOOKUP *lu)
1594 {
1595     unsigned char sigalgstr[2];
1596     int secbits;
1597 
1598     /* See if sigalgs is recognised and if hash is enabled */
1599     if (!tls1_lookup_md(lu, NULL))
1600         return 0;
1601     /* DSA is not allowed in TLS 1.3 */
1602     if (SSL_IS_TLS13(s) && lu->sig == EVP_PKEY_DSA)
1603         return 0;
1604     /* TODO(OpenSSL1.2) fully axe DSA/etc. in ClientHello per TLS 1.3 spec */
1605     if (!s->server && !SSL_IS_DTLS(s) && s->s3->tmp.min_ver >= TLS1_3_VERSION
1606         && (lu->sig == EVP_PKEY_DSA || lu->hash_idx == SSL_MD_SHA1_IDX
1607             || lu->hash_idx == SSL_MD_MD5_IDX
1608             || lu->hash_idx == SSL_MD_SHA224_IDX))
1609         return 0;
1610 
1611     /* See if public key algorithm allowed */
1612     if (ssl_cert_is_disabled(lu->sig_idx))
1613         return 0;
1614 
1615     if (lu->sig == NID_id_GostR3410_2012_256
1616             || lu->sig == NID_id_GostR3410_2012_512
1617             || lu->sig == NID_id_GostR3410_2001) {
1618         /* We never allow GOST sig algs on the server with TLSv1.3 */
1619         if (s->server && SSL_IS_TLS13(s))
1620             return 0;
1621         if (!s->server
1622                 && s->method->version == TLS_ANY_VERSION
1623                 && s->s3->tmp.max_ver >= TLS1_3_VERSION) {
1624             int i, num;
1625             STACK_OF(SSL_CIPHER) *sk;
1626 
1627             /*
1628              * We're a client that could negotiate TLSv1.3. We only allow GOST
1629              * sig algs if we could negotiate TLSv1.2 or below and we have GOST
1630              * ciphersuites enabled.
1631              */
1632 
1633             if (s->s3->tmp.min_ver >= TLS1_3_VERSION)
1634                 return 0;
1635 
1636             sk = SSL_get_ciphers(s);
1637             num = sk != NULL ? sk_SSL_CIPHER_num(sk) : 0;
1638             for (i = 0; i < num; i++) {
1639                 const SSL_CIPHER *c;
1640 
1641                 c = sk_SSL_CIPHER_value(sk, i);
1642                 /* Skip disabled ciphers */
1643                 if (ssl_cipher_disabled(s, c, SSL_SECOP_CIPHER_SUPPORTED, 0))
1644                     continue;
1645 
1646                 if ((c->algorithm_mkey & SSL_kGOST) != 0)
1647                     break;
1648             }
1649             if (i == num)
1650                 return 0;
1651         }
1652     }
1653 
1654     /* Finally see if security callback allows it */
1655     secbits = sigalg_security_bits(lu);
1656     sigalgstr[0] = (lu->sigalg >> 8) & 0xff;
1657     sigalgstr[1] = lu->sigalg & 0xff;
1658     return ssl_security(s, op, secbits, lu->hash, (void *)sigalgstr);
1659 }
1660 
1661 /*
1662  * Get a mask of disabled public key algorithms based on supported signature
1663  * algorithms. For example if no signature algorithm supports RSA then RSA is
1664  * disabled.
1665  */
1666 
1667 void ssl_set_sig_mask(uint32_t *pmask_a, SSL *s, int op)
1668 {
1669     const uint16_t *sigalgs;
1670     size_t i, sigalgslen;
1671     uint32_t disabled_mask = SSL_aRSA | SSL_aDSS | SSL_aECDSA;
1672     /*
1673      * Go through all signature algorithms seeing if we support any
1674      * in disabled_mask.
1675      */
1676     sigalgslen = tls12_get_psigalgs(s, 1, &sigalgs);
1677     for (i = 0; i < sigalgslen; i++, sigalgs++) {
1678         const SIGALG_LOOKUP *lu = tls1_lookup_sigalg(*sigalgs);
1679         const SSL_CERT_LOOKUP *clu;
1680 
1681         if (lu == NULL)
1682             continue;
1683 
1684         clu = ssl_cert_lookup_by_idx(lu->sig_idx);
1685 	if (clu == NULL)
1686 		continue;
1687 
1688         /* If algorithm is disabled see if we can enable it */
1689         if ((clu->amask & disabled_mask) != 0
1690                 && tls12_sigalg_allowed(s, op, lu))
1691             disabled_mask &= ~clu->amask;
1692     }
1693     *pmask_a |= disabled_mask;
1694 }
1695 
1696 int tls12_copy_sigalgs(SSL *s, WPACKET *pkt,
1697                        const uint16_t *psig, size_t psiglen)
1698 {
1699     size_t i;
1700     int rv = 0;
1701 
1702     for (i = 0; i < psiglen; i++, psig++) {
1703         const SIGALG_LOOKUP *lu = tls1_lookup_sigalg(*psig);
1704 
1705         if (!tls12_sigalg_allowed(s, SSL_SECOP_SIGALG_SUPPORTED, lu))
1706             continue;
1707         if (!WPACKET_put_bytes_u16(pkt, *psig))
1708             return 0;
1709         /*
1710          * If TLS 1.3 must have at least one valid TLS 1.3 message
1711          * signing algorithm: i.e. neither RSA nor SHA1/SHA224
1712          */
1713         if (rv == 0 && (!SSL_IS_TLS13(s)
1714             || (lu->sig != EVP_PKEY_RSA
1715                 && lu->hash != NID_sha1
1716                 && lu->hash != NID_sha224)))
1717             rv = 1;
1718     }
1719     if (rv == 0)
1720         SSLerr(SSL_F_TLS12_COPY_SIGALGS, SSL_R_NO_SUITABLE_SIGNATURE_ALGORITHM);
1721     return rv;
1722 }
1723 
1724 /* Given preference and allowed sigalgs set shared sigalgs */
1725 static size_t tls12_shared_sigalgs(SSL *s, const SIGALG_LOOKUP **shsig,
1726                                    const uint16_t *pref, size_t preflen,
1727                                    const uint16_t *allow, size_t allowlen)
1728 {
1729     const uint16_t *ptmp, *atmp;
1730     size_t i, j, nmatch = 0;
1731     for (i = 0, ptmp = pref; i < preflen; i++, ptmp++) {
1732         const SIGALG_LOOKUP *lu = tls1_lookup_sigalg(*ptmp);
1733 
1734         /* Skip disabled hashes or signature algorithms */
1735         if (!tls12_sigalg_allowed(s, SSL_SECOP_SIGALG_SHARED, lu))
1736             continue;
1737         for (j = 0, atmp = allow; j < allowlen; j++, atmp++) {
1738             if (*ptmp == *atmp) {
1739                 nmatch++;
1740                 if (shsig)
1741                     *shsig++ = lu;
1742                 break;
1743             }
1744         }
1745     }
1746     return nmatch;
1747 }
1748 
1749 /* Set shared signature algorithms for SSL structures */
1750 static int tls1_set_shared_sigalgs(SSL *s)
1751 {
1752     const uint16_t *pref, *allow, *conf;
1753     size_t preflen, allowlen, conflen;
1754     size_t nmatch;
1755     const SIGALG_LOOKUP **salgs = NULL;
1756     CERT *c = s->cert;
1757     unsigned int is_suiteb = tls1_suiteb(s);
1758 
1759     OPENSSL_free(s->shared_sigalgs);
1760     s->shared_sigalgs = NULL;
1761     s->shared_sigalgslen = 0;
1762     /* If client use client signature algorithms if not NULL */
1763     if (!s->server && c->client_sigalgs && !is_suiteb) {
1764         conf = c->client_sigalgs;
1765         conflen = c->client_sigalgslen;
1766     } else if (c->conf_sigalgs && !is_suiteb) {
1767         conf = c->conf_sigalgs;
1768         conflen = c->conf_sigalgslen;
1769     } else
1770         conflen = tls12_get_psigalgs(s, 0, &conf);
1771     if (s->options & SSL_OP_CIPHER_SERVER_PREFERENCE || is_suiteb) {
1772         pref = conf;
1773         preflen = conflen;
1774         allow = s->s3->tmp.peer_sigalgs;
1775         allowlen = s->s3->tmp.peer_sigalgslen;
1776     } else {
1777         allow = conf;
1778         allowlen = conflen;
1779         pref = s->s3->tmp.peer_sigalgs;
1780         preflen = s->s3->tmp.peer_sigalgslen;
1781     }
1782     nmatch = tls12_shared_sigalgs(s, NULL, pref, preflen, allow, allowlen);
1783     if (nmatch) {
1784         if ((salgs = OPENSSL_malloc(nmatch * sizeof(*salgs))) == NULL) {
1785             SSLerr(SSL_F_TLS1_SET_SHARED_SIGALGS, ERR_R_MALLOC_FAILURE);
1786             return 0;
1787         }
1788         nmatch = tls12_shared_sigalgs(s, salgs, pref, preflen, allow, allowlen);
1789     } else {
1790         salgs = NULL;
1791     }
1792     s->shared_sigalgs = salgs;
1793     s->shared_sigalgslen = nmatch;
1794     return 1;
1795 }
1796 
1797 int tls1_save_u16(PACKET *pkt, uint16_t **pdest, size_t *pdestlen)
1798 {
1799     unsigned int stmp;
1800     size_t size, i;
1801     uint16_t *buf;
1802 
1803     size = PACKET_remaining(pkt);
1804 
1805     /* Invalid data length */
1806     if (size == 0 || (size & 1) != 0)
1807         return 0;
1808 
1809     size >>= 1;
1810 
1811     if ((buf = OPENSSL_malloc(size * sizeof(*buf))) == NULL)  {
1812         SSLerr(SSL_F_TLS1_SAVE_U16, ERR_R_MALLOC_FAILURE);
1813         return 0;
1814     }
1815     for (i = 0; i < size && PACKET_get_net_2(pkt, &stmp); i++)
1816         buf[i] = stmp;
1817 
1818     if (i != size) {
1819         OPENSSL_free(buf);
1820         return 0;
1821     }
1822 
1823     OPENSSL_free(*pdest);
1824     *pdest = buf;
1825     *pdestlen = size;
1826 
1827     return 1;
1828 }
1829 
1830 int tls1_save_sigalgs(SSL *s, PACKET *pkt, int cert)
1831 {
1832     /* Extension ignored for inappropriate versions */
1833     if (!SSL_USE_SIGALGS(s))
1834         return 1;
1835     /* Should never happen */
1836     if (s->cert == NULL)
1837         return 0;
1838 
1839     if (cert)
1840         return tls1_save_u16(pkt, &s->s3->tmp.peer_cert_sigalgs,
1841                              &s->s3->tmp.peer_cert_sigalgslen);
1842     else
1843         return tls1_save_u16(pkt, &s->s3->tmp.peer_sigalgs,
1844                              &s->s3->tmp.peer_sigalgslen);
1845 
1846 }
1847 
1848 /* Set preferred digest for each key type */
1849 
1850 int tls1_process_sigalgs(SSL *s)
1851 {
1852     size_t i;
1853     uint32_t *pvalid = s->s3->tmp.valid_flags;
1854 
1855     if (!tls1_set_shared_sigalgs(s))
1856         return 0;
1857 
1858     for (i = 0; i < SSL_PKEY_NUM; i++)
1859         pvalid[i] = 0;
1860 
1861     for (i = 0; i < s->shared_sigalgslen; i++) {
1862         const SIGALG_LOOKUP *sigptr = s->shared_sigalgs[i];
1863         int idx = sigptr->sig_idx;
1864 
1865         /* Ignore PKCS1 based sig algs in TLSv1.3 */
1866         if (SSL_IS_TLS13(s) && sigptr->sig == EVP_PKEY_RSA)
1867             continue;
1868         /* If not disabled indicate we can explicitly sign */
1869         if (pvalid[idx] == 0 && !ssl_cert_is_disabled(idx))
1870             pvalid[idx] = CERT_PKEY_EXPLICIT_SIGN | CERT_PKEY_SIGN;
1871     }
1872     return 1;
1873 }
1874 
1875 int SSL_get_sigalgs(SSL *s, int idx,
1876                     int *psign, int *phash, int *psignhash,
1877                     unsigned char *rsig, unsigned char *rhash)
1878 {
1879     uint16_t *psig = s->s3->tmp.peer_sigalgs;
1880     size_t numsigalgs = s->s3->tmp.peer_sigalgslen;
1881     if (psig == NULL || numsigalgs > INT_MAX)
1882         return 0;
1883     if (idx >= 0) {
1884         const SIGALG_LOOKUP *lu;
1885 
1886         if (idx >= (int)numsigalgs)
1887             return 0;
1888         psig += idx;
1889         if (rhash != NULL)
1890             *rhash = (unsigned char)((*psig >> 8) & 0xff);
1891         if (rsig != NULL)
1892             *rsig = (unsigned char)(*psig & 0xff);
1893         lu = tls1_lookup_sigalg(*psig);
1894         if (psign != NULL)
1895             *psign = lu != NULL ? lu->sig : NID_undef;
1896         if (phash != NULL)
1897             *phash = lu != NULL ? lu->hash : NID_undef;
1898         if (psignhash != NULL)
1899             *psignhash = lu != NULL ? lu->sigandhash : NID_undef;
1900     }
1901     return (int)numsigalgs;
1902 }
1903 
1904 int SSL_get_shared_sigalgs(SSL *s, int idx,
1905                            int *psign, int *phash, int *psignhash,
1906                            unsigned char *rsig, unsigned char *rhash)
1907 {
1908     const SIGALG_LOOKUP *shsigalgs;
1909     if (s->shared_sigalgs == NULL
1910         || idx < 0
1911         || idx >= (int)s->shared_sigalgslen
1912         || s->shared_sigalgslen > INT_MAX)
1913         return 0;
1914     shsigalgs = s->shared_sigalgs[idx];
1915     if (phash != NULL)
1916         *phash = shsigalgs->hash;
1917     if (psign != NULL)
1918         *psign = shsigalgs->sig;
1919     if (psignhash != NULL)
1920         *psignhash = shsigalgs->sigandhash;
1921     if (rsig != NULL)
1922         *rsig = (unsigned char)(shsigalgs->sigalg & 0xff);
1923     if (rhash != NULL)
1924         *rhash = (unsigned char)((shsigalgs->sigalg >> 8) & 0xff);
1925     return (int)s->shared_sigalgslen;
1926 }
1927 
1928 /* Maximum possible number of unique entries in sigalgs array */
1929 #define TLS_MAX_SIGALGCNT (OSSL_NELEM(sigalg_lookup_tbl) * 2)
1930 
1931 typedef struct {
1932     size_t sigalgcnt;
1933     /* TLSEXT_SIGALG_XXX values */
1934     uint16_t sigalgs[TLS_MAX_SIGALGCNT];
1935 } sig_cb_st;
1936 
1937 static void get_sigorhash(int *psig, int *phash, const char *str)
1938 {
1939     if (strcmp(str, "RSA") == 0) {
1940         *psig = EVP_PKEY_RSA;
1941     } else if (strcmp(str, "RSA-PSS") == 0 || strcmp(str, "PSS") == 0) {
1942         *psig = EVP_PKEY_RSA_PSS;
1943     } else if (strcmp(str, "DSA") == 0) {
1944         *psig = EVP_PKEY_DSA;
1945     } else if (strcmp(str, "ECDSA") == 0) {
1946         *psig = EVP_PKEY_EC;
1947     } else {
1948         *phash = OBJ_sn2nid(str);
1949         if (*phash == NID_undef)
1950             *phash = OBJ_ln2nid(str);
1951     }
1952 }
1953 /* Maximum length of a signature algorithm string component */
1954 #define TLS_MAX_SIGSTRING_LEN   40
1955 
1956 static int sig_cb(const char *elem, int len, void *arg)
1957 {
1958     sig_cb_st *sarg = arg;
1959     size_t i;
1960     const SIGALG_LOOKUP *s;
1961     char etmp[TLS_MAX_SIGSTRING_LEN], *p;
1962     int sig_alg = NID_undef, hash_alg = NID_undef;
1963     if (elem == NULL)
1964         return 0;
1965     if (sarg->sigalgcnt == TLS_MAX_SIGALGCNT)
1966         return 0;
1967     if (len > (int)(sizeof(etmp) - 1))
1968         return 0;
1969     memcpy(etmp, elem, len);
1970     etmp[len] = 0;
1971     p = strchr(etmp, '+');
1972     /*
1973      * We only allow SignatureSchemes listed in the sigalg_lookup_tbl;
1974      * if there's no '+' in the provided name, look for the new-style combined
1975      * name.  If not, match both sig+hash to find the needed SIGALG_LOOKUP.
1976      * Just sig+hash is not unique since TLS 1.3 adds rsa_pss_pss_* and
1977      * rsa_pss_rsae_* that differ only by public key OID; in such cases
1978      * we will pick the _rsae_ variant, by virtue of them appearing earlier
1979      * in the table.
1980      */
1981     if (p == NULL) {
1982         for (i = 0, s = sigalg_lookup_tbl; i < OSSL_NELEM(sigalg_lookup_tbl);
1983              i++, s++) {
1984             if (s->name != NULL && strcmp(etmp, s->name) == 0) {
1985                 sarg->sigalgs[sarg->sigalgcnt++] = s->sigalg;
1986                 break;
1987             }
1988         }
1989         if (i == OSSL_NELEM(sigalg_lookup_tbl))
1990             return 0;
1991     } else {
1992         *p = 0;
1993         p++;
1994         if (*p == 0)
1995             return 0;
1996         get_sigorhash(&sig_alg, &hash_alg, etmp);
1997         get_sigorhash(&sig_alg, &hash_alg, p);
1998         if (sig_alg == NID_undef || hash_alg == NID_undef)
1999             return 0;
2000         for (i = 0, s = sigalg_lookup_tbl; i < OSSL_NELEM(sigalg_lookup_tbl);
2001              i++, s++) {
2002             if (s->hash == hash_alg && s->sig == sig_alg) {
2003                 sarg->sigalgs[sarg->sigalgcnt++] = s->sigalg;
2004                 break;
2005             }
2006         }
2007         if (i == OSSL_NELEM(sigalg_lookup_tbl))
2008             return 0;
2009     }
2010 
2011     /* Reject duplicates */
2012     for (i = 0; i < sarg->sigalgcnt - 1; i++) {
2013         if (sarg->sigalgs[i] == sarg->sigalgs[sarg->sigalgcnt - 1]) {
2014             sarg->sigalgcnt--;
2015             return 0;
2016         }
2017     }
2018     return 1;
2019 }
2020 
2021 /*
2022  * Set supported signature algorithms based on a colon separated list of the
2023  * form sig+hash e.g. RSA+SHA512:DSA+SHA512
2024  */
2025 int tls1_set_sigalgs_list(CERT *c, const char *str, int client)
2026 {
2027     sig_cb_st sig;
2028     sig.sigalgcnt = 0;
2029     if (!CONF_parse_list(str, ':', 1, sig_cb, &sig))
2030         return 0;
2031     if (c == NULL)
2032         return 1;
2033     return tls1_set_raw_sigalgs(c, sig.sigalgs, sig.sigalgcnt, client);
2034 }
2035 
2036 int tls1_set_raw_sigalgs(CERT *c, const uint16_t *psigs, size_t salglen,
2037                      int client)
2038 {
2039     uint16_t *sigalgs;
2040 
2041     if ((sigalgs = OPENSSL_malloc(salglen * sizeof(*sigalgs))) == NULL) {
2042         SSLerr(SSL_F_TLS1_SET_RAW_SIGALGS, ERR_R_MALLOC_FAILURE);
2043         return 0;
2044     }
2045     memcpy(sigalgs, psigs, salglen * sizeof(*sigalgs));
2046 
2047     if (client) {
2048         OPENSSL_free(c->client_sigalgs);
2049         c->client_sigalgs = sigalgs;
2050         c->client_sigalgslen = salglen;
2051     } else {
2052         OPENSSL_free(c->conf_sigalgs);
2053         c->conf_sigalgs = sigalgs;
2054         c->conf_sigalgslen = salglen;
2055     }
2056 
2057     return 1;
2058 }
2059 
2060 int tls1_set_sigalgs(CERT *c, const int *psig_nids, size_t salglen, int client)
2061 {
2062     uint16_t *sigalgs, *sptr;
2063     size_t i;
2064 
2065     if (salglen & 1)
2066         return 0;
2067     if ((sigalgs = OPENSSL_malloc((salglen / 2) * sizeof(*sigalgs))) == NULL) {
2068         SSLerr(SSL_F_TLS1_SET_SIGALGS, ERR_R_MALLOC_FAILURE);
2069         return 0;
2070     }
2071     for (i = 0, sptr = sigalgs; i < salglen; i += 2) {
2072         size_t j;
2073         const SIGALG_LOOKUP *curr;
2074         int md_id = *psig_nids++;
2075         int sig_id = *psig_nids++;
2076 
2077         for (j = 0, curr = sigalg_lookup_tbl; j < OSSL_NELEM(sigalg_lookup_tbl);
2078              j++, curr++) {
2079             if (curr->hash == md_id && curr->sig == sig_id) {
2080                 *sptr++ = curr->sigalg;
2081                 break;
2082             }
2083         }
2084 
2085         if (j == OSSL_NELEM(sigalg_lookup_tbl))
2086             goto err;
2087     }
2088 
2089     if (client) {
2090         OPENSSL_free(c->client_sigalgs);
2091         c->client_sigalgs = sigalgs;
2092         c->client_sigalgslen = salglen / 2;
2093     } else {
2094         OPENSSL_free(c->conf_sigalgs);
2095         c->conf_sigalgs = sigalgs;
2096         c->conf_sigalgslen = salglen / 2;
2097     }
2098 
2099     return 1;
2100 
2101  err:
2102     OPENSSL_free(sigalgs);
2103     return 0;
2104 }
2105 
2106 static int tls1_check_sig_alg(SSL *s, X509 *x, int default_nid)
2107 {
2108     int sig_nid, use_pc_sigalgs = 0;
2109     size_t i;
2110     const SIGALG_LOOKUP *sigalg;
2111     size_t sigalgslen;
2112     if (default_nid == -1)
2113         return 1;
2114     sig_nid = X509_get_signature_nid(x);
2115     if (default_nid)
2116         return sig_nid == default_nid ? 1 : 0;
2117 
2118     if (SSL_IS_TLS13(s) && s->s3->tmp.peer_cert_sigalgs != NULL) {
2119         /*
2120          * If we're in TLSv1.3 then we only get here if we're checking the
2121          * chain. If the peer has specified peer_cert_sigalgs then we use them
2122          * otherwise we default to normal sigalgs.
2123          */
2124         sigalgslen = s->s3->tmp.peer_cert_sigalgslen;
2125         use_pc_sigalgs = 1;
2126     } else {
2127         sigalgslen = s->shared_sigalgslen;
2128     }
2129     for (i = 0; i < sigalgslen; i++) {
2130         sigalg = use_pc_sigalgs
2131                  ? tls1_lookup_sigalg(s->s3->tmp.peer_cert_sigalgs[i])
2132                  : s->shared_sigalgs[i];
2133         if (sigalg != NULL && sig_nid == sigalg->sigandhash)
2134             return 1;
2135     }
2136     return 0;
2137 }
2138 
2139 /* Check to see if a certificate issuer name matches list of CA names */
2140 static int ssl_check_ca_name(STACK_OF(X509_NAME) *names, X509 *x)
2141 {
2142     X509_NAME *nm;
2143     int i;
2144     nm = X509_get_issuer_name(x);
2145     for (i = 0; i < sk_X509_NAME_num(names); i++) {
2146         if (!X509_NAME_cmp(nm, sk_X509_NAME_value(names, i)))
2147             return 1;
2148     }
2149     return 0;
2150 }
2151 
2152 /*
2153  * Check certificate chain is consistent with TLS extensions and is usable by
2154  * server. This servers two purposes: it allows users to check chains before
2155  * passing them to the server and it allows the server to check chains before
2156  * attempting to use them.
2157  */
2158 
2159 /* Flags which need to be set for a certificate when strict mode not set */
2160 
2161 #define CERT_PKEY_VALID_FLAGS \
2162         (CERT_PKEY_EE_SIGNATURE|CERT_PKEY_EE_PARAM)
2163 /* Strict mode flags */
2164 #define CERT_PKEY_STRICT_FLAGS \
2165          (CERT_PKEY_VALID_FLAGS|CERT_PKEY_CA_SIGNATURE|CERT_PKEY_CA_PARAM \
2166          | CERT_PKEY_ISSUER_NAME|CERT_PKEY_CERT_TYPE)
2167 
2168 int tls1_check_chain(SSL *s, X509 *x, EVP_PKEY *pk, STACK_OF(X509) *chain,
2169                      int idx)
2170 {
2171     int i;
2172     int rv = 0;
2173     int check_flags = 0, strict_mode;
2174     CERT_PKEY *cpk = NULL;
2175     CERT *c = s->cert;
2176     uint32_t *pvalid;
2177     unsigned int suiteb_flags = tls1_suiteb(s);
2178     /* idx == -1 means checking server chains */
2179     if (idx != -1) {
2180         /* idx == -2 means checking client certificate chains */
2181         if (idx == -2) {
2182             cpk = c->key;
2183             idx = (int)(cpk - c->pkeys);
2184         } else
2185             cpk = c->pkeys + idx;
2186         pvalid = s->s3->tmp.valid_flags + idx;
2187         x = cpk->x509;
2188         pk = cpk->privatekey;
2189         chain = cpk->chain;
2190         strict_mode = c->cert_flags & SSL_CERT_FLAGS_CHECK_TLS_STRICT;
2191         /* If no cert or key, forget it */
2192         if (!x || !pk)
2193             goto end;
2194     } else {
2195         size_t certidx;
2196 
2197         if (!x || !pk)
2198             return 0;
2199 
2200         if (ssl_cert_lookup_by_pkey(pk, &certidx) == NULL)
2201             return 0;
2202         idx = certidx;
2203         pvalid = s->s3->tmp.valid_flags + idx;
2204 
2205         if (c->cert_flags & SSL_CERT_FLAGS_CHECK_TLS_STRICT)
2206             check_flags = CERT_PKEY_STRICT_FLAGS;
2207         else
2208             check_flags = CERT_PKEY_VALID_FLAGS;
2209         strict_mode = 1;
2210     }
2211 
2212     if (suiteb_flags) {
2213         int ok;
2214         if (check_flags)
2215             check_flags |= CERT_PKEY_SUITEB;
2216         ok = X509_chain_check_suiteb(NULL, x, chain, suiteb_flags);
2217         if (ok == X509_V_OK)
2218             rv |= CERT_PKEY_SUITEB;
2219         else if (!check_flags)
2220             goto end;
2221     }
2222 
2223     /*
2224      * Check all signature algorithms are consistent with signature
2225      * algorithms extension if TLS 1.2 or later and strict mode.
2226      */
2227     if (TLS1_get_version(s) >= TLS1_2_VERSION && strict_mode) {
2228         int default_nid;
2229         int rsign = 0;
2230         if (s->s3->tmp.peer_cert_sigalgs != NULL
2231                 || s->s3->tmp.peer_sigalgs != NULL) {
2232             default_nid = 0;
2233         /* If no sigalgs extension use defaults from RFC5246 */
2234         } else {
2235             switch (idx) {
2236             case SSL_PKEY_RSA:
2237                 rsign = EVP_PKEY_RSA;
2238                 default_nid = NID_sha1WithRSAEncryption;
2239                 break;
2240 
2241             case SSL_PKEY_DSA_SIGN:
2242                 rsign = EVP_PKEY_DSA;
2243                 default_nid = NID_dsaWithSHA1;
2244                 break;
2245 
2246             case SSL_PKEY_ECC:
2247                 rsign = EVP_PKEY_EC;
2248                 default_nid = NID_ecdsa_with_SHA1;
2249                 break;
2250 
2251             case SSL_PKEY_GOST01:
2252                 rsign = NID_id_GostR3410_2001;
2253                 default_nid = NID_id_GostR3411_94_with_GostR3410_2001;
2254                 break;
2255 
2256             case SSL_PKEY_GOST12_256:
2257                 rsign = NID_id_GostR3410_2012_256;
2258                 default_nid = NID_id_tc26_signwithdigest_gost3410_2012_256;
2259                 break;
2260 
2261             case SSL_PKEY_GOST12_512:
2262                 rsign = NID_id_GostR3410_2012_512;
2263                 default_nid = NID_id_tc26_signwithdigest_gost3410_2012_512;
2264                 break;
2265 
2266             default:
2267                 default_nid = -1;
2268                 break;
2269             }
2270         }
2271         /*
2272          * If peer sent no signature algorithms extension and we have set
2273          * preferred signature algorithms check we support sha1.
2274          */
2275         if (default_nid > 0 && c->conf_sigalgs) {
2276             size_t j;
2277             const uint16_t *p = c->conf_sigalgs;
2278             for (j = 0; j < c->conf_sigalgslen; j++, p++) {
2279                 const SIGALG_LOOKUP *lu = tls1_lookup_sigalg(*p);
2280 
2281                 if (lu != NULL && lu->hash == NID_sha1 && lu->sig == rsign)
2282                     break;
2283             }
2284             if (j == c->conf_sigalgslen) {
2285                 if (check_flags)
2286                     goto skip_sigs;
2287                 else
2288                     goto end;
2289             }
2290         }
2291         /* Check signature algorithm of each cert in chain */
2292         if (SSL_IS_TLS13(s)) {
2293             /*
2294              * We only get here if the application has called SSL_check_chain(),
2295              * so check_flags is always set.
2296              */
2297             if (find_sig_alg(s, x, pk) != NULL)
2298                 rv |= CERT_PKEY_EE_SIGNATURE;
2299         } else if (!tls1_check_sig_alg(s, x, default_nid)) {
2300             if (!check_flags)
2301                 goto end;
2302         } else
2303             rv |= CERT_PKEY_EE_SIGNATURE;
2304         rv |= CERT_PKEY_CA_SIGNATURE;
2305         for (i = 0; i < sk_X509_num(chain); i++) {
2306             if (!tls1_check_sig_alg(s, sk_X509_value(chain, i), default_nid)) {
2307                 if (check_flags) {
2308                     rv &= ~CERT_PKEY_CA_SIGNATURE;
2309                     break;
2310                 } else
2311                     goto end;
2312             }
2313         }
2314     }
2315     /* Else not TLS 1.2, so mark EE and CA signing algorithms OK */
2316     else if (check_flags)
2317         rv |= CERT_PKEY_EE_SIGNATURE | CERT_PKEY_CA_SIGNATURE;
2318  skip_sigs:
2319     /* Check cert parameters are consistent */
2320     if (tls1_check_cert_param(s, x, 1))
2321         rv |= CERT_PKEY_EE_PARAM;
2322     else if (!check_flags)
2323         goto end;
2324     if (!s->server)
2325         rv |= CERT_PKEY_CA_PARAM;
2326     /* In strict mode check rest of chain too */
2327     else if (strict_mode) {
2328         rv |= CERT_PKEY_CA_PARAM;
2329         for (i = 0; i < sk_X509_num(chain); i++) {
2330             X509 *ca = sk_X509_value(chain, i);
2331             if (!tls1_check_cert_param(s, ca, 0)) {
2332                 if (check_flags) {
2333                     rv &= ~CERT_PKEY_CA_PARAM;
2334                     break;
2335                 } else
2336                     goto end;
2337             }
2338         }
2339     }
2340     if (!s->server && strict_mode) {
2341         STACK_OF(X509_NAME) *ca_dn;
2342         int check_type = 0;
2343         switch (EVP_PKEY_id(pk)) {
2344         case EVP_PKEY_RSA:
2345             check_type = TLS_CT_RSA_SIGN;
2346             break;
2347         case EVP_PKEY_DSA:
2348             check_type = TLS_CT_DSS_SIGN;
2349             break;
2350         case EVP_PKEY_EC:
2351             check_type = TLS_CT_ECDSA_SIGN;
2352             break;
2353         }
2354         if (check_type) {
2355             const uint8_t *ctypes = s->s3->tmp.ctype;
2356             size_t j;
2357 
2358             for (j = 0; j < s->s3->tmp.ctype_len; j++, ctypes++) {
2359                 if (*ctypes == check_type) {
2360                     rv |= CERT_PKEY_CERT_TYPE;
2361                     break;
2362                 }
2363             }
2364             if (!(rv & CERT_PKEY_CERT_TYPE) && !check_flags)
2365                 goto end;
2366         } else {
2367             rv |= CERT_PKEY_CERT_TYPE;
2368         }
2369 
2370         ca_dn = s->s3->tmp.peer_ca_names;
2371 
2372         if (!sk_X509_NAME_num(ca_dn))
2373             rv |= CERT_PKEY_ISSUER_NAME;
2374 
2375         if (!(rv & CERT_PKEY_ISSUER_NAME)) {
2376             if (ssl_check_ca_name(ca_dn, x))
2377                 rv |= CERT_PKEY_ISSUER_NAME;
2378         }
2379         if (!(rv & CERT_PKEY_ISSUER_NAME)) {
2380             for (i = 0; i < sk_X509_num(chain); i++) {
2381                 X509 *xtmp = sk_X509_value(chain, i);
2382                 if (ssl_check_ca_name(ca_dn, xtmp)) {
2383                     rv |= CERT_PKEY_ISSUER_NAME;
2384                     break;
2385                 }
2386             }
2387         }
2388         if (!check_flags && !(rv & CERT_PKEY_ISSUER_NAME))
2389             goto end;
2390     } else
2391         rv |= CERT_PKEY_ISSUER_NAME | CERT_PKEY_CERT_TYPE;
2392 
2393     if (!check_flags || (rv & check_flags) == check_flags)
2394         rv |= CERT_PKEY_VALID;
2395 
2396  end:
2397 
2398     if (TLS1_get_version(s) >= TLS1_2_VERSION)
2399         rv |= *pvalid & (CERT_PKEY_EXPLICIT_SIGN | CERT_PKEY_SIGN);
2400     else
2401         rv |= CERT_PKEY_SIGN | CERT_PKEY_EXPLICIT_SIGN;
2402 
2403     /*
2404      * When checking a CERT_PKEY structure all flags are irrelevant if the
2405      * chain is invalid.
2406      */
2407     if (!check_flags) {
2408         if (rv & CERT_PKEY_VALID) {
2409             *pvalid = rv;
2410         } else {
2411             /* Preserve sign and explicit sign flag, clear rest */
2412             *pvalid &= CERT_PKEY_EXPLICIT_SIGN | CERT_PKEY_SIGN;
2413             return 0;
2414         }
2415     }
2416     return rv;
2417 }
2418 
2419 /* Set validity of certificates in an SSL structure */
2420 void tls1_set_cert_validity(SSL *s)
2421 {
2422     tls1_check_chain(s, NULL, NULL, NULL, SSL_PKEY_RSA);
2423     tls1_check_chain(s, NULL, NULL, NULL, SSL_PKEY_RSA_PSS_SIGN);
2424     tls1_check_chain(s, NULL, NULL, NULL, SSL_PKEY_DSA_SIGN);
2425     tls1_check_chain(s, NULL, NULL, NULL, SSL_PKEY_ECC);
2426     tls1_check_chain(s, NULL, NULL, NULL, SSL_PKEY_GOST01);
2427     tls1_check_chain(s, NULL, NULL, NULL, SSL_PKEY_GOST12_256);
2428     tls1_check_chain(s, NULL, NULL, NULL, SSL_PKEY_GOST12_512);
2429     tls1_check_chain(s, NULL, NULL, NULL, SSL_PKEY_ED25519);
2430     tls1_check_chain(s, NULL, NULL, NULL, SSL_PKEY_ED448);
2431 }
2432 
2433 /* User level utility function to check a chain is suitable */
2434 int SSL_check_chain(SSL *s, X509 *x, EVP_PKEY *pk, STACK_OF(X509) *chain)
2435 {
2436     return tls1_check_chain(s, x, pk, chain, -1);
2437 }
2438 
2439 #ifndef OPENSSL_NO_DH
2440 DH *ssl_get_auto_dh(SSL *s)
2441 {
2442     DH *dhp = NULL;
2443     BIGNUM *p = NULL, *g = NULL;
2444     int dh_secbits = 80;
2445     if (s->cert->dh_tmp_auto != 2) {
2446         if (s->s3->tmp.new_cipher->algorithm_auth & (SSL_aNULL | SSL_aPSK)) {
2447             if (s->s3->tmp.new_cipher->strength_bits == 256)
2448                 dh_secbits = 128;
2449             else
2450                 dh_secbits = 80;
2451         } else {
2452             if (s->s3->tmp.cert == NULL)
2453                 return NULL;
2454             dh_secbits = EVP_PKEY_security_bits(s->s3->tmp.cert->privatekey);
2455         }
2456     }
2457 
2458     dhp = DH_new();
2459     if (dhp == NULL)
2460         return NULL;
2461     g = BN_new();
2462     if (g == NULL || !BN_set_word(g, 2)) {
2463         DH_free(dhp);
2464         BN_free(g);
2465         return NULL;
2466     }
2467     if (dh_secbits >= 192)
2468         p = BN_get_rfc3526_prime_8192(NULL);
2469     else if (dh_secbits >= 152)
2470         p = BN_get_rfc3526_prime_4096(NULL);
2471     else if (dh_secbits >= 128)
2472         p = BN_get_rfc3526_prime_3072(NULL);
2473     else if (dh_secbits >= 112)
2474         p = BN_get_rfc3526_prime_2048(NULL);
2475     else
2476         p = BN_get_rfc2409_prime_1024(NULL);
2477     if (p == NULL || !DH_set0_pqg(dhp, p, NULL, g)) {
2478         DH_free(dhp);
2479         BN_free(p);
2480         BN_free(g);
2481         return NULL;
2482     }
2483     return dhp;
2484 }
2485 #endif
2486 
2487 static int ssl_security_cert_key(SSL *s, SSL_CTX *ctx, X509 *x, int op)
2488 {
2489     int secbits = -1;
2490     EVP_PKEY *pkey = X509_get0_pubkey(x);
2491     if (pkey) {
2492         /*
2493          * If no parameters this will return -1 and fail using the default
2494          * security callback for any non-zero security level. This will
2495          * reject keys which omit parameters but this only affects DSA and
2496          * omission of parameters is never (?) done in practice.
2497          */
2498         secbits = EVP_PKEY_security_bits(pkey);
2499     }
2500     if (s)
2501         return ssl_security(s, op, secbits, 0, x);
2502     else
2503         return ssl_ctx_security(ctx, op, secbits, 0, x);
2504 }
2505 
2506 static int ssl_security_cert_sig(SSL *s, SSL_CTX *ctx, X509 *x, int op)
2507 {
2508     /* Lookup signature algorithm digest */
2509     int secbits, nid, pknid;
2510     /* Don't check signature if self signed */
2511     if ((X509_get_extension_flags(x) & EXFLAG_SS) != 0)
2512         return 1;
2513     if (!X509_get_signature_info(x, &nid, &pknid, &secbits, NULL))
2514         secbits = -1;
2515     /* If digest NID not defined use signature NID */
2516     if (nid == NID_undef)
2517         nid = pknid;
2518     if (s)
2519         return ssl_security(s, op, secbits, nid, x);
2520     else
2521         return ssl_ctx_security(ctx, op, secbits, nid, x);
2522 }
2523 
2524 int ssl_security_cert(SSL *s, SSL_CTX *ctx, X509 *x, int vfy, int is_ee)
2525 {
2526     if (vfy)
2527         vfy = SSL_SECOP_PEER;
2528     if (is_ee) {
2529         if (!ssl_security_cert_key(s, ctx, x, SSL_SECOP_EE_KEY | vfy))
2530             return SSL_R_EE_KEY_TOO_SMALL;
2531     } else {
2532         if (!ssl_security_cert_key(s, ctx, x, SSL_SECOP_CA_KEY | vfy))
2533             return SSL_R_CA_KEY_TOO_SMALL;
2534     }
2535     if (!ssl_security_cert_sig(s, ctx, x, SSL_SECOP_CA_MD | vfy))
2536         return SSL_R_CA_MD_TOO_WEAK;
2537     return 1;
2538 }
2539 
2540 /*
2541  * Check security of a chain, if |sk| includes the end entity certificate then
2542  * |x| is NULL. If |vfy| is 1 then we are verifying a peer chain and not sending
2543  * one to the peer. Return values: 1 if ok otherwise error code to use
2544  */
2545 
2546 int ssl_security_cert_chain(SSL *s, STACK_OF(X509) *sk, X509 *x, int vfy)
2547 {
2548     int rv, start_idx, i;
2549     if (x == NULL) {
2550         x = sk_X509_value(sk, 0);
2551         start_idx = 1;
2552     } else
2553         start_idx = 0;
2554 
2555     rv = ssl_security_cert(s, NULL, x, vfy, 1);
2556     if (rv != 1)
2557         return rv;
2558 
2559     for (i = start_idx; i < sk_X509_num(sk); i++) {
2560         x = sk_X509_value(sk, i);
2561         rv = ssl_security_cert(s, NULL, x, vfy, 0);
2562         if (rv != 1)
2563             return rv;
2564     }
2565     return 1;
2566 }
2567 
2568 /*
2569  * For TLS 1.2 servers check if we have a certificate which can be used
2570  * with the signature algorithm "lu" and return index of certificate.
2571  */
2572 
2573 static int tls12_get_cert_sigalg_idx(const SSL *s, const SIGALG_LOOKUP *lu)
2574 {
2575     int sig_idx = lu->sig_idx;
2576     const SSL_CERT_LOOKUP *clu = ssl_cert_lookup_by_idx(sig_idx);
2577 
2578     /* If not recognised or not supported by cipher mask it is not suitable */
2579     if (clu == NULL
2580             || (clu->amask & s->s3->tmp.new_cipher->algorithm_auth) == 0
2581             || (clu->nid == EVP_PKEY_RSA_PSS
2582                 && (s->s3->tmp.new_cipher->algorithm_mkey & SSL_kRSA) != 0))
2583         return -1;
2584 
2585     return s->s3->tmp.valid_flags[sig_idx] & CERT_PKEY_VALID ? sig_idx : -1;
2586 }
2587 
2588 /*
2589  * Checks the given cert against signature_algorithm_cert restrictions sent by
2590  * the peer (if any) as well as whether the hash from the sigalg is usable with
2591  * the key.
2592  * Returns true if the cert is usable and false otherwise.
2593  */
2594 static int check_cert_usable(SSL *s, const SIGALG_LOOKUP *sig, X509 *x,
2595                              EVP_PKEY *pkey)
2596 {
2597     const SIGALG_LOOKUP *lu;
2598     int mdnid, pknid, default_mdnid;
2599     size_t i;
2600 
2601     /* If the EVP_PKEY reports a mandatory digest, allow nothing else. */
2602     ERR_set_mark();
2603     if (EVP_PKEY_get_default_digest_nid(pkey, &default_mdnid) == 2 &&
2604         sig->hash != default_mdnid)
2605             return 0;
2606 
2607     /* If it didn't report a mandatory NID, for whatever reasons,
2608      * just clear the error and allow all hashes to be used. */
2609     ERR_pop_to_mark();
2610 
2611     if (s->s3->tmp.peer_cert_sigalgs != NULL) {
2612         for (i = 0; i < s->s3->tmp.peer_cert_sigalgslen; i++) {
2613             lu = tls1_lookup_sigalg(s->s3->tmp.peer_cert_sigalgs[i]);
2614             if (lu == NULL
2615                 || !X509_get_signature_info(x, &mdnid, &pknid, NULL, NULL))
2616                 continue;
2617             /*
2618              * TODO this does not differentiate between the
2619              * rsa_pss_pss_* and rsa_pss_rsae_* schemes since we do not
2620              * have a chain here that lets us look at the key OID in the
2621              * signing certificate.
2622              */
2623             if (mdnid == lu->hash && pknid == lu->sig)
2624                 return 1;
2625         }
2626         return 0;
2627     }
2628     return 1;
2629 }
2630 
2631 /*
2632  * Returns true if |s| has a usable certificate configured for use
2633  * with signature scheme |sig|.
2634  * "Usable" includes a check for presence as well as applying
2635  * the signature_algorithm_cert restrictions sent by the peer (if any).
2636  * Returns false if no usable certificate is found.
2637  */
2638 static int has_usable_cert(SSL *s, const SIGALG_LOOKUP *sig, int idx)
2639 {
2640     /* TLS 1.2 callers can override sig->sig_idx, but not TLS 1.3 callers. */
2641     if (idx == -1)
2642         idx = sig->sig_idx;
2643     if (!ssl_has_cert(s, idx))
2644         return 0;
2645 
2646     return check_cert_usable(s, sig, s->cert->pkeys[idx].x509,
2647                              s->cert->pkeys[idx].privatekey);
2648 }
2649 
2650 /*
2651  * Returns true if the supplied cert |x| and key |pkey| is usable with the
2652  * specified signature scheme |sig|, or false otherwise.
2653  */
2654 static int is_cert_usable(SSL *s, const SIGALG_LOOKUP *sig, X509 *x,
2655                           EVP_PKEY *pkey)
2656 {
2657     size_t idx;
2658 
2659     if (ssl_cert_lookup_by_pkey(pkey, &idx) == NULL)
2660         return 0;
2661 
2662     /* Check the key is consistent with the sig alg */
2663     if ((int)idx != sig->sig_idx)
2664         return 0;
2665 
2666     return check_cert_usable(s, sig, x, pkey);
2667 }
2668 
2669 /*
2670  * Find a signature scheme that works with the supplied certificate |x| and key
2671  * |pkey|. |x| and |pkey| may be NULL in which case we additionally look at our
2672  * available certs/keys to find one that works.
2673  */
2674 static const SIGALG_LOOKUP *find_sig_alg(SSL *s, X509 *x, EVP_PKEY *pkey)
2675 {
2676     const SIGALG_LOOKUP *lu = NULL;
2677     size_t i;
2678 #ifndef OPENSSL_NO_EC
2679     int curve = -1;
2680 #endif
2681     EVP_PKEY *tmppkey;
2682 
2683     /* Look for a shared sigalgs matching possible certificates */
2684     for (i = 0; i < s->shared_sigalgslen; i++) {
2685         lu = s->shared_sigalgs[i];
2686 
2687         /* Skip SHA1, SHA224, DSA and RSA if not PSS */
2688         if (lu->hash == NID_sha1
2689             || lu->hash == NID_sha224
2690             || lu->sig == EVP_PKEY_DSA
2691             || lu->sig == EVP_PKEY_RSA)
2692             continue;
2693         /* Check that we have a cert, and signature_algorithms_cert */
2694         if (!tls1_lookup_md(lu, NULL))
2695             continue;
2696         if ((pkey == NULL && !has_usable_cert(s, lu, -1))
2697                 || (pkey != NULL && !is_cert_usable(s, lu, x, pkey)))
2698             continue;
2699 
2700         tmppkey = (pkey != NULL) ? pkey
2701                                  : s->cert->pkeys[lu->sig_idx].privatekey;
2702 
2703         if (lu->sig == EVP_PKEY_EC) {
2704 #ifndef OPENSSL_NO_EC
2705             if (curve == -1) {
2706                 EC_KEY *ec = EVP_PKEY_get0_EC_KEY(tmppkey);
2707                 curve = EC_GROUP_get_curve_name(EC_KEY_get0_group(ec));
2708             }
2709             if (lu->curve != NID_undef && curve != lu->curve)
2710                 continue;
2711 #else
2712             continue;
2713 #endif
2714         } else if (lu->sig == EVP_PKEY_RSA_PSS) {
2715             /* validate that key is large enough for the signature algorithm */
2716             if (!rsa_pss_check_min_key_size(EVP_PKEY_get0(tmppkey), lu))
2717                 continue;
2718         }
2719         break;
2720     }
2721 
2722     if (i == s->shared_sigalgslen)
2723         return NULL;
2724 
2725     return lu;
2726 }
2727 
2728 /*
2729  * Choose an appropriate signature algorithm based on available certificates
2730  * Sets chosen certificate and signature algorithm.
2731  *
2732  * For servers if we fail to find a required certificate it is a fatal error,
2733  * an appropriate error code is set and a TLS alert is sent.
2734  *
2735  * For clients fatalerrs is set to 0. If a certificate is not suitable it is not
2736  * a fatal error: we will either try another certificate or not present one
2737  * to the server. In this case no error is set.
2738  */
2739 int tls_choose_sigalg(SSL *s, int fatalerrs)
2740 {
2741     const SIGALG_LOOKUP *lu = NULL;
2742     int sig_idx = -1;
2743 
2744     s->s3->tmp.cert = NULL;
2745     s->s3->tmp.sigalg = NULL;
2746 
2747     if (SSL_IS_TLS13(s)) {
2748         lu = find_sig_alg(s, NULL, NULL);
2749         if (lu == NULL) {
2750             if (!fatalerrs)
2751                 return 1;
2752             SSLfatal(s, SSL_AD_HANDSHAKE_FAILURE, SSL_F_TLS_CHOOSE_SIGALG,
2753                      SSL_R_NO_SUITABLE_SIGNATURE_ALGORITHM);
2754             return 0;
2755         }
2756     } else {
2757         /* If ciphersuite doesn't require a cert nothing to do */
2758         if (!(s->s3->tmp.new_cipher->algorithm_auth & SSL_aCERT))
2759             return 1;
2760         if (!s->server && !ssl_has_cert(s, s->cert->key - s->cert->pkeys))
2761                 return 1;
2762 
2763         if (SSL_USE_SIGALGS(s)) {
2764             size_t i;
2765             if (s->s3->tmp.peer_sigalgs != NULL) {
2766 #ifndef OPENSSL_NO_EC
2767                 int curve;
2768 
2769                 /* For Suite B need to match signature algorithm to curve */
2770                 if (tls1_suiteb(s)) {
2771                     EC_KEY *ec = EVP_PKEY_get0_EC_KEY(s->cert->pkeys[SSL_PKEY_ECC].privatekey);
2772                     curve = EC_GROUP_get_curve_name(EC_KEY_get0_group(ec));
2773                 } else {
2774                     curve = -1;
2775                 }
2776 #endif
2777 
2778                 /*
2779                  * Find highest preference signature algorithm matching
2780                  * cert type
2781                  */
2782                 for (i = 0; i < s->shared_sigalgslen; i++) {
2783                     lu = s->shared_sigalgs[i];
2784 
2785                     if (s->server) {
2786                         if ((sig_idx = tls12_get_cert_sigalg_idx(s, lu)) == -1)
2787                             continue;
2788                     } else {
2789                         int cc_idx = s->cert->key - s->cert->pkeys;
2790 
2791                         sig_idx = lu->sig_idx;
2792                         if (cc_idx != sig_idx)
2793                             continue;
2794                     }
2795                     /* Check that we have a cert, and sig_algs_cert */
2796                     if (!has_usable_cert(s, lu, sig_idx))
2797                         continue;
2798                     if (lu->sig == EVP_PKEY_RSA_PSS) {
2799                         /* validate that key is large enough for the signature algorithm */
2800                         EVP_PKEY *pkey = s->cert->pkeys[sig_idx].privatekey;
2801 
2802                         if (!rsa_pss_check_min_key_size(EVP_PKEY_get0(pkey), lu))
2803                             continue;
2804                     }
2805 #ifndef OPENSSL_NO_EC
2806                     if (curve == -1 || lu->curve == curve)
2807 #endif
2808                         break;
2809                 }
2810 #ifndef OPENSSL_NO_GOST
2811                 /*
2812                  * Some Windows-based implementations do not send GOST algorithms indication
2813                  * in supported_algorithms extension, so when we have GOST-based ciphersuite,
2814                  * we have to assume GOST support.
2815                  */
2816                 if (i == s->shared_sigalgslen && s->s3->tmp.new_cipher->algorithm_auth & (SSL_aGOST01 | SSL_aGOST12)) {
2817                   if ((lu = tls1_get_legacy_sigalg(s, -1)) == NULL) {
2818                     if (!fatalerrs)
2819                       return 1;
2820                     SSLfatal(s, SSL_AD_HANDSHAKE_FAILURE,
2821                              SSL_F_TLS_CHOOSE_SIGALG,
2822                              SSL_R_NO_SUITABLE_SIGNATURE_ALGORITHM);
2823                     return 0;
2824                   } else {
2825                     i = 0;
2826                     sig_idx = lu->sig_idx;
2827                   }
2828                 }
2829 #endif
2830                 if (i == s->shared_sigalgslen) {
2831                     if (!fatalerrs)
2832                         return 1;
2833                     SSLfatal(s, SSL_AD_HANDSHAKE_FAILURE,
2834                              SSL_F_TLS_CHOOSE_SIGALG,
2835                              SSL_R_NO_SUITABLE_SIGNATURE_ALGORITHM);
2836                     return 0;
2837                 }
2838             } else {
2839                 /*
2840                  * If we have no sigalg use defaults
2841                  */
2842                 const uint16_t *sent_sigs;
2843                 size_t sent_sigslen;
2844 
2845                 if ((lu = tls1_get_legacy_sigalg(s, -1)) == NULL) {
2846                     if (!fatalerrs)
2847                         return 1;
2848                     SSLfatal(s, SSL_AD_INTERNAL_ERROR, SSL_F_TLS_CHOOSE_SIGALG,
2849                              ERR_R_INTERNAL_ERROR);
2850                     return 0;
2851                 }
2852 
2853                 /* Check signature matches a type we sent */
2854                 sent_sigslen = tls12_get_psigalgs(s, 1, &sent_sigs);
2855                 for (i = 0; i < sent_sigslen; i++, sent_sigs++) {
2856                     if (lu->sigalg == *sent_sigs
2857                             && has_usable_cert(s, lu, lu->sig_idx))
2858                         break;
2859                 }
2860                 if (i == sent_sigslen) {
2861                     if (!fatalerrs)
2862                         return 1;
2863                     SSLfatal(s, SSL_AD_ILLEGAL_PARAMETER,
2864                              SSL_F_TLS_CHOOSE_SIGALG,
2865                              SSL_R_WRONG_SIGNATURE_TYPE);
2866                     return 0;
2867                 }
2868             }
2869         } else {
2870             if ((lu = tls1_get_legacy_sigalg(s, -1)) == NULL) {
2871                 if (!fatalerrs)
2872                     return 1;
2873                 SSLfatal(s, SSL_AD_INTERNAL_ERROR, SSL_F_TLS_CHOOSE_SIGALG,
2874                          ERR_R_INTERNAL_ERROR);
2875                 return 0;
2876             }
2877         }
2878     }
2879     if (sig_idx == -1)
2880         sig_idx = lu->sig_idx;
2881     s->s3->tmp.cert = &s->cert->pkeys[sig_idx];
2882     s->cert->key = s->s3->tmp.cert;
2883     s->s3->tmp.sigalg = lu;
2884     return 1;
2885 }
2886 
2887 int SSL_CTX_set_tlsext_max_fragment_length(SSL_CTX *ctx, uint8_t mode)
2888 {
2889     if (mode != TLSEXT_max_fragment_length_DISABLED
2890             && !IS_MAX_FRAGMENT_LENGTH_EXT_VALID(mode)) {
2891         SSLerr(SSL_F_SSL_CTX_SET_TLSEXT_MAX_FRAGMENT_LENGTH,
2892                SSL_R_SSL3_EXT_INVALID_MAX_FRAGMENT_LENGTH);
2893         return 0;
2894     }
2895 
2896     ctx->ext.max_fragment_len_mode = mode;
2897     return 1;
2898 }
2899 
2900 int SSL_set_tlsext_max_fragment_length(SSL *ssl, uint8_t mode)
2901 {
2902     if (mode != TLSEXT_max_fragment_length_DISABLED
2903             && !IS_MAX_FRAGMENT_LENGTH_EXT_VALID(mode)) {
2904         SSLerr(SSL_F_SSL_SET_TLSEXT_MAX_FRAGMENT_LENGTH,
2905                SSL_R_SSL3_EXT_INVALID_MAX_FRAGMENT_LENGTH);
2906         return 0;
2907     }
2908 
2909     ssl->ext.max_fragment_len_mode = mode;
2910     return 1;
2911 }
2912 
2913 uint8_t SSL_SESSION_get_max_fragment_length(const SSL_SESSION *session)
2914 {
2915     return session->ext.max_fragment_len_mode;
2916 }
2917