1 /***************************************************************************
3 * Project ___| | | | _ \| |
5 * | (__| |_| | _ <| |___
6 * \___|\___/|_| \_\_____|
8 * Copyright (C) 1998 - 2015, Daniel Stenberg, <daniel@haxx.se>, et al.
10 * This software is licensed as described in the file COPYING, which
11 * you should have received as part of this distribution. The terms
12 * are also available at https://curl.haxx.se/docs/copyright.html.
14 * You may opt to use, copy, modify, merge, publish, distribute and/or sell
15 * copies of the Software, and permit persons to whom the Software is
16 * furnished to do so, under the terms of the COPYING file.
18 * This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY
19 * KIND, either express or implied.
21 ***************************************************************************/
23 /* This file is for implementing all "generic" SSL functions that all libcurl
24 internals should use. It is then responsible for calling the proper
27 SSL-functions in libcurl should call functions in this source file, and not
28 to any specific SSL-layer.
30 Curl_ssl_ - prefix for generic ones
31 Curl_ossl_ - prefix for OpenSSL ones
32 Curl_gtls_ - prefix for GnuTLS ones
33 Curl_nss_ - prefix for NSS ones
34 Curl_gskit_ - prefix for GSKit ones
35 Curl_polarssl_ - prefix for PolarSSL ones
36 Curl_cyassl_ - prefix for CyaSSL ones
37 Curl_schannel_ - prefix for Schannel SSPI ones
38 Curl_darwinssl_ - prefix for SecureTransport (Darwin) ones
40 Note that this source code uses curlssl_* functions, and they are all
41 defines/macros #defined by the lib-specific header files.
43 "SSL/TLS Strong Encryption: An Introduction"
44 https://httpd.apache.org/docs/2.0/ssl/ssl_intro.html
47 #include "curl_setup.h"
49 #ifdef HAVE_SYS_TYPES_H
50 #include <sys/types.h>
52 #ifdef HAVE_SYS_STAT_H
61 #include "vtls.h" /* generic SSL protos etc */
71 #include "curl_base64.h"
72 #include "curl_printf.h"
74 /* The last #include files should be: */
75 #include "curl_memory.h"
78 /* convenience macro to check if this handle is using a shared SSL session */
79 #define SSLSESSION_SHARED(data) (data->share && \
80 (data->share->specifier & \
81 (1<<CURL_LOCK_DATA_SSL_SESSION)))
83 static bool safe_strequal(char* str1, char* str2)
86 /* both pointers point to something then compare them */
87 return (0 != Curl_raw_equal(str1, str2)) ? TRUE : FALSE;
89 /* if both pointers are NULL then treat them as equal */
90 return (!str1 && !str2) ? TRUE : FALSE;
94 Curl_ssl_config_matches(struct ssl_config_data* data,
95 struct ssl_config_data* needle)
97 if((data->version == needle->version) &&
98 (data->verifypeer == needle->verifypeer) &&
99 (data->verifyhost == needle->verifyhost) &&
100 safe_strequal(data->CApath, needle->CApath) &&
101 safe_strequal(data->CAfile, needle->CAfile) &&
102 safe_strequal(data->random_file, needle->random_file) &&
103 safe_strequal(data->egdsocket, needle->egdsocket) &&
104 safe_strequal(data->cipher_list, needle->cipher_list))
111 Curl_clone_ssl_config(struct ssl_config_data *source,
112 struct ssl_config_data *dest)
114 dest->sessionid = source->sessionid;
115 dest->verifyhost = source->verifyhost;
116 dest->verifypeer = source->verifypeer;
117 dest->version = source->version;
120 dest->CAfile = strdup(source->CAfile);
128 dest->CApath = strdup(source->CApath);
135 if(source->cipher_list) {
136 dest->cipher_list = strdup(source->cipher_list);
137 if(!dest->cipher_list)
141 dest->cipher_list = NULL;
143 if(source->egdsocket) {
144 dest->egdsocket = strdup(source->egdsocket);
149 dest->egdsocket = NULL;
151 if(source->random_file) {
152 dest->random_file = strdup(source->random_file);
153 if(!dest->random_file)
157 dest->random_file = NULL;
162 void Curl_free_ssl_config(struct ssl_config_data* sslc)
164 Curl_safefree(sslc->CAfile);
165 Curl_safefree(sslc->CApath);
166 Curl_safefree(sslc->cipher_list);
167 Curl_safefree(sslc->egdsocket);
168 Curl_safefree(sslc->random_file);
173 * Curl_rand() returns a random unsigned integer, 32bit.
175 * This non-SSL function is put here only because this file is the only one
176 * with knowledge of what the underlying SSL libraries provide in terms of
179 * NOTE: 'data' may be passed in as NULL when coming from external API without
184 unsigned int Curl_rand(struct SessionHandle *data)
187 static unsigned int randseed;
188 static bool seeded = FALSE;
191 char *force_entropy = getenv("CURL_ENTROPY");
194 size_t elen = strlen(force_entropy);
195 size_t clen = sizeof(randseed);
196 size_t min = elen < clen ? elen : clen;
197 memcpy((char *)&randseed, force_entropy, min);
206 /* data may be NULL! */
207 if(!Curl_ssl_random(data, (unsigned char *)&r, sizeof(r)))
210 /* If Curl_ssl_random() returns non-zero it couldn't offer randomness and we
211 instead perform a "best effort" */
215 /* if there's a random file to read a seed from, use it */
216 int fd = open(RANDOM_FILE, O_RDONLY);
218 /* read random data into the randseed variable */
219 ssize_t nread = read(fd, &randseed, sizeof(randseed));
220 if(nread == sizeof(randseed))
228 struct timeval now = curlx_tvnow();
229 infof(data, "WARNING: Using weak random seed\n");
230 randseed += (unsigned int)now.tv_usec + (unsigned int)now.tv_sec;
231 randseed = randseed * 1103515245 + 12345;
232 randseed = randseed * 1103515245 + 12345;
233 randseed = randseed * 1103515245 + 12345;
237 /* Return an unsigned 32-bit pseudo-random number. */
238 r = randseed = randseed * 1103515245 + 12345;
239 return (r << 16) | ((r >> 16) & 0xFFFF);
242 int Curl_ssl_backend(void)
244 return (int)CURL_SSL_BACKEND;
249 /* "global" init done? */
250 static bool init_ssl=FALSE;
255 * @retval 0 error initializing SSL
256 * @retval 1 SSL initialized successfully
258 int Curl_ssl_init(void)
260 /* make sure this is only done once */
263 init_ssl = TRUE; /* never again */
265 return curlssl_init();
270 void Curl_ssl_cleanup(void)
273 /* only cleanup if we did a previous init */
279 static bool ssl_prefs_check(struct SessionHandle *data)
281 /* check for CURLOPT_SSLVERSION invalid parameter value */
282 if((data->set.ssl.version < 0)
283 || (data->set.ssl.version >= CURL_SSLVERSION_LAST)) {
284 failf(data, "Unrecognized parameter value passed via CURLOPT_SSLVERSION");
291 Curl_ssl_connect(struct connectdata *conn, int sockindex)
295 if(!ssl_prefs_check(conn->data))
296 return CURLE_SSL_CONNECT_ERROR;
298 /* mark this is being ssl-enabled from here on. */
299 conn->ssl[sockindex].use = TRUE;
300 conn->ssl[sockindex].state = ssl_connection_negotiating;
302 result = curlssl_connect(conn, sockindex);
305 Curl_pgrsTime(conn->data, TIMER_APPCONNECT); /* SSL is connected */
311 Curl_ssl_connect_nonblocking(struct connectdata *conn, int sockindex,
316 if(!ssl_prefs_check(conn->data))
317 return CURLE_SSL_CONNECT_ERROR;
319 /* mark this is being ssl requested from here on. */
320 conn->ssl[sockindex].use = TRUE;
321 #ifdef curlssl_connect_nonblocking
322 result = curlssl_connect_nonblocking(conn, sockindex, done);
324 *done = TRUE; /* fallback to BLOCKING */
325 result = curlssl_connect(conn, sockindex);
326 #endif /* non-blocking connect support */
328 Curl_pgrsTime(conn->data, TIMER_APPCONNECT); /* SSL is connected */
333 * Check if there's a session ID for the given connection in the cache, and if
334 * there's one suitable, it is provided. Returns TRUE when no entry matched.
336 bool Curl_ssl_getsessionid(struct connectdata *conn,
337 void **ssl_sessionid,
338 size_t *idsize) /* set 0 if unknown */
340 struct curl_ssl_session *check;
341 struct SessionHandle *data = conn->data;
344 bool no_match = TRUE;
346 *ssl_sessionid = NULL;
348 if(!conn->ssl_config.sessionid)
349 /* session ID re-use is disabled */
353 if(SSLSESSION_SHARED(data)) {
354 Curl_share_lock(data, CURL_LOCK_DATA_SSL_SESSION, CURL_LOCK_ACCESS_SINGLE);
355 general_age = &data->share->sessionage;
358 general_age = &data->state.sessionage;
360 for(i = 0; i < data->set.ssl.max_ssl_sessions; i++) {
361 check = &data->state.session[i];
362 if(!check->sessionid)
363 /* not session ID means blank entry */
365 if(Curl_raw_equal(conn->host.name, check->name) &&
366 (conn->remote_port == check->remote_port) &&
367 Curl_ssl_config_matches(&conn->ssl_config, &check->ssl_config)) {
368 /* yes, we have a session ID! */
369 (*general_age)++; /* increase general age */
370 check->age = *general_age; /* set this as used in this age */
371 *ssl_sessionid = check->sessionid;
373 *idsize = check->idsize;
380 if(SSLSESSION_SHARED(data))
381 Curl_share_unlock(data, CURL_LOCK_DATA_SSL_SESSION);
387 * Kill a single session ID entry in the cache.
389 void Curl_ssl_kill_session(struct curl_ssl_session *session)
391 if(session->sessionid) {
392 /* defensive check */
394 /* free the ID the SSL-layer specific way */
395 curlssl_session_free(session->sessionid);
397 session->sessionid = NULL;
398 session->age = 0; /* fresh */
400 Curl_free_ssl_config(&session->ssl_config);
402 Curl_safefree(session->name);
407 * Delete the given session ID from the cache.
409 void Curl_ssl_delsessionid(struct connectdata *conn, void *ssl_sessionid)
412 struct SessionHandle *data=conn->data;
414 if(SSLSESSION_SHARED(data))
415 Curl_share_lock(data, CURL_LOCK_DATA_SSL_SESSION, CURL_LOCK_ACCESS_SINGLE);
417 for(i = 0; i < data->set.ssl.max_ssl_sessions; i++) {
418 struct curl_ssl_session *check = &data->state.session[i];
420 if(check->sessionid == ssl_sessionid) {
421 Curl_ssl_kill_session(check);
426 if(SSLSESSION_SHARED(data))
427 Curl_share_unlock(data, CURL_LOCK_DATA_SSL_SESSION);
431 * Store session id in the session cache. The ID passed on to this function
432 * must already have been extracted and allocated the proper way for the SSL
433 * layer. Curl_XXXX_session_free() will be called to free/kill the session ID
436 CURLcode Curl_ssl_addsessionid(struct connectdata *conn,
441 struct SessionHandle *data=conn->data; /* the mother of all structs */
442 struct curl_ssl_session *store = &data->state.session[0];
443 long oldest_age=data->state.session[0].age; /* zero if unused */
447 /* Even though session ID re-use might be disabled, that only disables USING
448 IT. We still store it here in case the re-using is again enabled for an
451 clone_host = strdup(conn->host.name);
453 return CURLE_OUT_OF_MEMORY; /* bail out */
455 /* Now we should add the session ID and the host name to the cache, (remove
456 the oldest if necessary) */
458 /* If using shared SSL session, lock! */
459 if(SSLSESSION_SHARED(data)) {
460 Curl_share_lock(data, CURL_LOCK_DATA_SSL_SESSION, CURL_LOCK_ACCESS_SINGLE);
461 general_age = &data->share->sessionage;
464 general_age = &data->state.sessionage;
467 /* find an empty slot for us, or find the oldest */
468 for(i = 1; (i < data->set.ssl.max_ssl_sessions) &&
469 data->state.session[i].sessionid; i++) {
470 if(data->state.session[i].age < oldest_age) {
471 oldest_age = data->state.session[i].age;
472 store = &data->state.session[i];
475 if(i == data->set.ssl.max_ssl_sessions)
476 /* cache is full, we must "kill" the oldest entry! */
477 Curl_ssl_kill_session(store);
479 store = &data->state.session[i]; /* use this slot */
481 /* now init the session struct wisely */
482 store->sessionid = ssl_sessionid;
483 store->idsize = idsize;
484 store->age = *general_age; /* set current age */
485 /* free it if there's one already present */
487 store->name = clone_host; /* clone host name */
488 store->remote_port = conn->remote_port; /* port number */
492 if(SSLSESSION_SHARED(data))
493 Curl_share_unlock(data, CURL_LOCK_DATA_SSL_SESSION);
495 if(!Curl_clone_ssl_config(&conn->ssl_config, &store->ssl_config)) {
496 store->sessionid = NULL; /* let caller free sessionid */
498 return CURLE_OUT_OF_MEMORY;
505 void Curl_ssl_close_all(struct SessionHandle *data)
508 /* kill the session ID cache if not shared */
509 if(data->state.session && !SSLSESSION_SHARED(data)) {
510 for(i = 0; i < data->set.ssl.max_ssl_sessions; i++)
511 /* the single-killer function handles empty table slots */
512 Curl_ssl_kill_session(&data->state.session[i]);
514 /* free the cache data */
515 Curl_safefree(data->state.session);
518 curlssl_close_all(data);
521 void Curl_ssl_close(struct connectdata *conn, int sockindex)
523 DEBUGASSERT((sockindex <= 1) && (sockindex >= -1));
524 curlssl_close(conn, sockindex);
527 CURLcode Curl_ssl_shutdown(struct connectdata *conn, int sockindex)
529 if(curlssl_shutdown(conn, sockindex))
530 return CURLE_SSL_SHUTDOWN_FAILED;
532 conn->ssl[sockindex].use = FALSE; /* get back to ordinary socket usage */
533 conn->ssl[sockindex].state = ssl_connection_none;
535 conn->recv[sockindex] = Curl_recv_plain;
536 conn->send[sockindex] = Curl_send_plain;
541 /* Selects an SSL crypto engine
543 CURLcode Curl_ssl_set_engine(struct SessionHandle *data, const char *engine)
545 return curlssl_set_engine(data, engine);
548 /* Selects the default SSL crypto engine
550 CURLcode Curl_ssl_set_engine_default(struct SessionHandle *data)
552 return curlssl_set_engine_default(data);
555 /* Return list of OpenSSL crypto engine names. */
556 struct curl_slist *Curl_ssl_engines_list(struct SessionHandle *data)
558 return curlssl_engines_list(data);
562 * This sets up a session ID cache to the specified size. Make sure this code
563 * is agnostic to what underlying SSL technology we use.
565 CURLcode Curl_ssl_initsessions(struct SessionHandle *data, size_t amount)
567 struct curl_ssl_session *session;
569 if(data->state.session)
570 /* this is just a precaution to prevent multiple inits */
573 session = calloc(amount, sizeof(struct curl_ssl_session));
575 return CURLE_OUT_OF_MEMORY;
577 /* store the info in the SSL section */
578 data->set.ssl.max_ssl_sessions = amount;
579 data->state.session = session;
580 data->state.sessionage = 1; /* this is brand new */
584 size_t Curl_ssl_version(char *buffer, size_t size)
586 return curlssl_version(buffer, size);
590 * This function tries to determine connection status.
593 * 1 means the connection is still in place
594 * 0 means the connection has been closed
595 * -1 means the connection status is unknown
597 int Curl_ssl_check_cxn(struct connectdata *conn)
599 return curlssl_check_cxn(conn);
602 bool Curl_ssl_data_pending(const struct connectdata *conn,
605 return curlssl_data_pending(conn, connindex);
608 void Curl_ssl_free_certinfo(struct SessionHandle *data)
611 struct curl_certinfo *ci = &data->info.certs;
613 if(ci->num_of_certs) {
614 /* free all individual lists used */
615 for(i=0; i<ci->num_of_certs; i++) {
616 curl_slist_free_all(ci->certinfo[i]);
617 ci->certinfo[i] = NULL;
620 free(ci->certinfo); /* free the actual array too */
622 ci->num_of_certs = 0;
626 CURLcode Curl_ssl_init_certinfo(struct SessionHandle *data, int num)
628 struct curl_certinfo *ci = &data->info.certs;
629 struct curl_slist **table;
631 /* Free any previous certificate information structures */
632 Curl_ssl_free_certinfo(data);
634 /* Allocate the required certificate information structures */
635 table = calloc((size_t) num, sizeof(struct curl_slist *));
637 return CURLE_OUT_OF_MEMORY;
639 ci->num_of_certs = num;
640 ci->certinfo = table;
646 * 'value' is NOT a zero terminated string
648 CURLcode Curl_ssl_push_certinfo_len(struct SessionHandle *data,
654 struct curl_certinfo * ci = &data->info.certs;
656 struct curl_slist * nl;
657 CURLcode result = CURLE_OK;
658 size_t labellen = strlen(label);
659 size_t outlen = labellen + 1 + valuelen + 1; /* label:value\0 */
661 output = malloc(outlen);
663 return CURLE_OUT_OF_MEMORY;
665 /* sprintf the label and colon */
666 snprintf(output, outlen, "%s:", label);
668 /* memcpy the value (it might not be zero terminated) */
669 memcpy(&output[labellen+1], value, valuelen);
671 /* zero terminate the output */
672 output[labellen + 1 + valuelen] = 0;
674 nl = Curl_slist_append_nodup(ci->certinfo[certnum], output);
677 curl_slist_free_all(ci->certinfo[certnum]);
678 result = CURLE_OUT_OF_MEMORY;
681 ci->certinfo[certnum] = nl;
686 * This is a convenience function for push_certinfo_len that takes a zero
689 CURLcode Curl_ssl_push_certinfo(struct SessionHandle *data,
694 size_t valuelen = strlen(value);
696 return Curl_ssl_push_certinfo_len(data, certnum, label, value, valuelen);
699 int Curl_ssl_random(struct SessionHandle *data,
700 unsigned char *entropy,
703 return curlssl_random(data, entropy, length);
707 * Public key pem to der conversion
710 static CURLcode pubkey_pem_to_der(const char *pem,
711 unsigned char **der, size_t *der_len)
713 char *stripped_pem, *begin_pos, *end_pos;
714 size_t pem_count, stripped_pem_count = 0, pem_len;
717 /* if no pem, exit. */
719 return CURLE_BAD_CONTENT_ENCODING;
721 begin_pos = strstr(pem, "-----BEGIN PUBLIC KEY-----");
723 return CURLE_BAD_CONTENT_ENCODING;
725 pem_count = begin_pos - pem;
726 /* Invalid if not at beginning AND not directly following \n */
727 if(0 != pem_count && '\n' != pem[pem_count - 1])
728 return CURLE_BAD_CONTENT_ENCODING;
730 /* 26 is length of "-----BEGIN PUBLIC KEY-----" */
733 /* Invalid if not directly following \n */
734 end_pos = strstr(pem + pem_count, "\n-----END PUBLIC KEY-----");
736 return CURLE_BAD_CONTENT_ENCODING;
738 pem_len = end_pos - pem;
740 stripped_pem = malloc(pem_len - pem_count + 1);
742 return CURLE_OUT_OF_MEMORY;
745 * Here we loop through the pem array one character at a time between the
746 * correct indices, and place each character that is not '\n' or '\r'
747 * into the stripped_pem array, which should represent the raw base64 string
749 while(pem_count < pem_len) {
750 if('\n' != pem[pem_count] && '\r' != pem[pem_count])
751 stripped_pem[stripped_pem_count++] = pem[pem_count];
754 /* Place the null terminator in the correct place */
755 stripped_pem[stripped_pem_count] = '\0';
757 result = Curl_base64_decode(stripped_pem, der, der_len);
759 Curl_safefree(stripped_pem);
765 * Generic pinned public key check.
768 CURLcode Curl_pin_peer_pubkey(struct SessionHandle *data,
769 const char *pinnedpubkey,
770 const unsigned char *pubkey, size_t pubkeylen)
773 unsigned char *buf = NULL, *pem_ptr = NULL;
775 size_t size, pem_len;
777 CURLcode result = CURLE_SSL_PINNEDPUBKEYNOTMATCH;
778 #ifdef curlssl_sha256sum
780 size_t encodedlen, pinkeylen;
781 char *encoded, *pinkeycopy, *begin_pos, *end_pos;
782 unsigned char *sha256sumdigest = NULL;
785 /* if a path wasn't specified, don't pin */
788 if(!pubkey || !pubkeylen)
791 #ifdef curlssl_sha256sum
792 /* only do this if pinnedpubkey starts with "sha256//", length 8 */
793 if(strncmp(pinnedpubkey, "sha256//", 8) == 0) {
794 /* compute sha256sum of public key */
795 sha256sumdigest = malloc(SHA256_DIGEST_LENGTH);
797 return CURLE_OUT_OF_MEMORY;
798 curlssl_sha256sum(pubkey, pubkeylen,
799 sha256sumdigest, SHA256_DIGEST_LENGTH);
800 encode = Curl_base64_encode(data, (char *)sha256sumdigest,
801 SHA256_DIGEST_LENGTH, &encoded, &encodedlen);
802 Curl_safefree(sha256sumdigest);
807 infof(data, "\t public key hash: sha256//%s\n", encoded);
809 /* it starts with sha256//, copy so we can modify it */
810 pinkeylen = strlen(pinnedpubkey) + 1;
811 pinkeycopy = malloc(pinkeylen);
813 Curl_safefree(encoded);
814 return CURLE_OUT_OF_MEMORY;
816 memcpy(pinkeycopy, pinnedpubkey, pinkeylen);
817 /* point begin_pos to the copy, and start extracting keys */
818 begin_pos = pinkeycopy;
820 end_pos = strstr(begin_pos, ";sha256//");
822 * if there is an end_pos, null terminate,
823 * otherwise it'll go to the end of the original string
828 /* compare base64 sha256 digests, 8 is the length of "sha256//" */
829 if(encodedlen == strlen(begin_pos + 8) &&
830 !memcmp(encoded, begin_pos + 8, encodedlen)) {
836 * change back the null-terminator we changed earlier,
837 * and look for next begin
841 begin_pos = strstr(end_pos, "sha256//");
843 } while(end_pos && begin_pos);
844 Curl_safefree(encoded);
845 Curl_safefree(pinkeycopy);
852 fp = fopen(pinnedpubkey, "rb");
857 /* Determine the file's size */
858 if(fseek(fp, 0, SEEK_END))
860 filesize = ftell(fp);
861 if(fseek(fp, 0, SEEK_SET))
863 if(filesize < 0 || filesize > MAX_PINNED_PUBKEY_SIZE)
867 * if the size of our certificate is bigger than the file
868 * size then it can't match
870 size = curlx_sotouz((curl_off_t) filesize);
875 * Allocate buffer for the pinned key
876 * With 1 additional byte for null terminator in case of PEM key
878 buf = malloc(size + 1);
882 /* Returns number of elements read, which should be 1 */
883 if((int) fread(buf, size, 1, fp) != 1)
886 /* If the sizes are the same, it can't be base64 encoded, must be der */
887 if(pubkeylen == size) {
888 if(!memcmp(pubkey, buf, pubkeylen))
894 * Otherwise we will assume it's PEM and try to decode it
895 * after placing null terminator
898 pem_read = pubkey_pem_to_der((const char *)buf, &pem_ptr, &pem_len);
899 /* if it wasn't read successfully, exit */
904 * if the size of our certificate doesn't match the size of
905 * the decoded file, they can't be the same, otherwise compare
907 if(pubkeylen == pem_len && !memcmp(pubkey, pem_ptr, pubkeylen))
912 Curl_safefree(pem_ptr);
918 #ifndef CURL_DISABLE_CRYPTO_AUTH
919 CURLcode Curl_ssl_md5sum(unsigned char *tmp, /* input */
921 unsigned char *md5sum, /* output */
924 #ifdef curlssl_md5sum
925 curlssl_md5sum(tmp, tmplen, md5sum, md5len);
931 MD5pw = Curl_MD5_init(Curl_DIGEST_MD5);
933 return CURLE_OUT_OF_MEMORY;
934 Curl_MD5_update(MD5pw, tmp, curlx_uztoui(tmplen));
935 Curl_MD5_final(MD5pw, md5sum);
942 * Check whether the SSL backend supports the status_request extension.
944 bool Curl_ssl_cert_status_request(void)
946 #ifdef curlssl_cert_status_request
947 return curlssl_cert_status_request();
954 * Check whether the SSL backend supports false start.
956 bool Curl_ssl_false_start(void)
958 #ifdef curlssl_false_start
959 return curlssl_false_start();