1 /*********************************************************************
3 * File : $Source: /cvsroot/ijbswa/current/ssl.c,v $
5 * Purpose : File with TLS/SSL extension. Contains methods for
6 * creating, using and closing TLS/SSL connections.
8 * Copyright : Written by and Copyright (c) 2017 Vaclav Svec. FIT CVUT.
9 * Copyright (C) 2018-2019 by Fabian Keil <fk@fabiankeil.de>
11 * This program is free software; you can redistribute it
12 * and/or modify it under the terms of the GNU General
13 * Public License as published by the Free Software
14 * Foundation; either version 2 of the License, or (at
15 * your option) any later version.
17 * This program is distributed in the hope that it will
18 * be useful, but WITHOUT ANY WARRANTY; without even the
19 * implied warranty of MERCHANTABILITY or FITNESS FOR A
20 * PARTICULAR PURPOSE. See the GNU General Public
21 * License for more details.
23 * The GNU General Public License should be included with
24 * this file. If not, you can view it at
25 * http://www.gnu.org/copyleft/gpl.html
26 * or write to the Free Software Foundation, Inc., 59
27 * Temple Place - Suite 330, Boston, MA 02111-1307, USA.
29 *********************************************************************/
34 #if !defined(MBEDTLS_CONFIG_FILE)
35 # include "mbedtls/config.h"
37 # include MBEDTLS_CONFIG_FILE
40 #include "mbedtls/md5.h"
41 #include "mbedtls/pem.h"
42 #include "mbedtls/base64.h"
43 #include "mbedtls/error.h"
54 * Macros for searching begin and end of certificates.
55 * Necessary to convert structure mbedtls_x509_crt to crt file.
57 #define PEM_BEGIN_CRT "-----BEGIN CERTIFICATE-----\n"
58 #define PEM_END_CRT "-----END CERTIFICATE-----\n"
63 #define ERROR_BUF_SIZE 1024 /* Size of buffer for error messages */
64 #define CERTIFICATE_BUF_SIZE 16384 /* Size of buffer to save certificate. Value 4096 is mbedtls library buffer size for certificate in DER form */
65 #define PRIVATE_KEY_BUF_SIZE 16000 /* Size of buffer to save private key. Value 16000 is taken from mbed TLS library examples. */
66 #define RSA_KEY_PUBLIC_EXPONENT 65537 /* Public exponent for RSA private key generating */
67 #define RSA_KEYSIZE 2048 /* Size of generated RSA keys */
68 #define GENERATED_CERT_VALID_FROM "20100101000000" /* Date and time, which will be set in generated certificates as parameter valid from */
69 #define GENERATED_CERT_VALID_TO "20401231235959" /* Date and time, which will be set in generated certificates as parameter valid to */
70 #define CERT_SIGNATURE_ALGORITHM MBEDTLS_MD_SHA256 /* The MD algorithm to use for the signature */
71 #define CERT_SERIAL_NUM_LENGTH 4 /* Bytes of hash to be used for creating serial number of certificate. Min=2 and max=16 */
72 #define INVALID_CERT_INFO_BUF_SIZE 2048 /* Size of buffer for message with information about reason of certificate invalidity. Data after the end of buffer will not be saved */
73 #define CERT_PARAM_COMMON_NAME "CN="
74 #define CERT_PARAM_ORGANIZATION ",O="
75 #define CERT_PARAM_ORG_UNIT ",OU="
76 #define CERT_PARAM_COUNTRY ",C=CZ"
77 #define KEY_FILE_TYPE ".pem"
78 #define CERT_FILE_TYPE ".crt"
79 #define CERT_SUBJECT_PASSWORD ""
80 #define CERT_INFO_PREFIX ""
83 * Properties of cert for generating
86 char *issuer_crt; /* filename of the issuer certificate */
87 char *subject_key; /* filename of the subject key file */
88 char *issuer_key; /* filename of the issuer key file */
89 const char *subject_pwd; /* password for the subject key file */
90 const char *issuer_pwd; /* password for the issuer key file */
91 char *output_file; /* where to store the constructed key file */
92 const char *subject_name; /* subject name for certificate */
93 char issuer_name[ISSUER_NAME_BUF_SIZE]; /* issuer name for certificate */
94 const char *not_before; /* validity period not before */
95 const char *not_after; /* validity period not after */
96 const char *serial; /* serial number string */
97 int is_ca; /* is a CA certificate */
98 int max_pathlen; /* maximum CA path length */
102 * Properties of key for generating
105 mbedtls_pk_type_t type; /* type of key to generate */
106 int rsa_keysize; /* length of key in bits */
107 char *key_file_path; /* filename of the key file */
110 static int generate_webpage_certificate(struct client_state *csp);
111 static char *make_certs_path(const char *conf_dir, const char *file_name, const char *suffix);
112 static int file_exists(const char *path);
113 static int host_to_hash(struct client_state *csp);
114 static int ssl_verify_callback(void *data, mbedtls_x509_crt *crt, int depth, uint32_t *flags);
115 static void free_certificate_chain(struct client_state *csp);
116 static unsigned int get_certificate_mutex_id(struct client_state *csp);
117 static unsigned long get_certificate_serial(struct client_state *csp);
118 static void free_client_ssl_structures(struct client_state *csp);
119 static void free_server_ssl_structures(struct client_state *csp);
120 static int seed_rng(struct client_state *csp);
122 /*********************************************************************
124 * Function : client_use_ssl
126 * Description : Tests if client in current client state structure
127 * should use SSL connection or standard connection.
130 * 1 : csp = Current client state (buffers, headers, etc...)
132 * Returns : If client should use TLS/SSL connection, 1 is returned.
133 * Otherwise 0 is returned.
135 *********************************************************************/
136 extern int client_use_ssl(const struct client_state *csp)
138 return csp->http->client_ssl;
142 /*********************************************************************
144 * Function : server_use_ssl
146 * Description : Tests if server in current client state structure
147 * should use SSL connection or standard connection.
150 * 1 : csp = Current client state (buffers, headers, etc...)
152 * Returns : If server should use TLS/SSL connection, 1 is returned.
153 * Otherwise 0 is returned.
155 *********************************************************************/
156 extern int server_use_ssl(const struct client_state *csp)
158 return csp->http->server_ssl;
162 /*********************************************************************
164 * Function : is_ssl_pending
166 * Description : Tests if there are some waiting data on ssl connection
169 * 1 : ssl = SSL context to test
171 * Returns : 0 => No data are pending
172 * >0 => Pending data length
174 *********************************************************************/
175 extern size_t is_ssl_pending(mbedtls_ssl_context *ssl)
182 return mbedtls_ssl_get_bytes_avail(ssl);
186 /*********************************************************************
188 * Function : ssl_send_data
190 * Description : Sends the content of buf (for n bytes) to given SSL
191 * connection context.
194 * 1 : ssl = SSL context to send data to
195 * 2 : buf = Pointer to data to be sent
196 * 3 : len = Length of data to be sent to the SSL context
198 * Returns : Length of sent data or negative value on error.
200 *********************************************************************/
201 extern int ssl_send_data(mbedtls_ssl_context *ssl, const unsigned char *buf, size_t len)
204 size_t max_fragment_size = 0; /* Maximal length of data in one SSL fragment*/
205 int send_len = 0; /* length of one data part to send */
206 int pos = 0; /* Position of unsent part in buffer */
213 /* Getting maximal length of data sent in one fragment */
214 max_fragment_size = mbedtls_ssl_get_max_frag_len(ssl);
217 * Whole buffer must be sent in many fragments, because each fragment
218 * has its maximal length.
222 /* Compute length of data, that can be send in next fragment */
223 if ((pos + (int)max_fragment_size) > len)
225 send_len = (int)len - pos;
229 send_len = (int)max_fragment_size;
233 * Sending one part of the buffer
235 while ((ret = mbedtls_ssl_write(ssl,
236 (const unsigned char *)(buf + pos),
237 (size_t)send_len)) < 0)
239 if (ret != MBEDTLS_ERR_SSL_WANT_READ &&
240 ret != MBEDTLS_ERR_SSL_WANT_WRITE)
242 char err_buf[ERROR_BUF_SIZE];
244 mbedtls_strerror(ret, err_buf, sizeof(err_buf));
245 log_error(LOG_LEVEL_ERROR,
246 "Sending data over TLS/SSL failed: %s", err_buf);
250 /* Adding count of sent bytes to position in buffer */
251 pos = pos + send_len;
258 /*********************************************************************
260 * Function : ssl_recv_data
262 * Description : Receives data from given SSL context and puts
266 * 1 : ssl = SSL context to receive data from
267 * 2 : buf = Pointer to buffer where data will be written
268 * 3 : max_length = Maximum number of bytes to read
270 * Returns : Number of bytes read, 0 for EOF, or negative
273 *********************************************************************/
274 extern int ssl_recv_data(mbedtls_ssl_context *ssl, unsigned char *buf, size_t max_length)
277 memset(buf, 0, max_length);
280 * Receiving data from SSL context into buffer
284 ret = mbedtls_ssl_read(ssl, buf, max_length);
285 } while (ret == MBEDTLS_ERR_SSL_WANT_READ
286 || ret == MBEDTLS_ERR_SSL_WANT_WRITE);
290 char err_buf[ERROR_BUF_SIZE];
292 mbedtls_strerror(ret, err_buf, sizeof(err_buf));
293 log_error(LOG_LEVEL_ERROR,
294 "Receiving data over TLS/SSL failed: %s", err_buf);
301 /*********************************************************************
303 * Function : ssl_flush_socket
305 * Description : Send any pending "buffered" content with given
306 * SSL connection. Alternative to function flush_socket.
309 * 1 : ssl = SSL context to send buffer to
310 * 2 : iob = The I/O buffer to flush, usually csp->iob.
312 * Returns : On success, the number of bytes send are returned (zero
313 * indicates nothing was sent). On error, -1 is returned.
315 *********************************************************************/
316 extern long ssl_flush_socket(mbedtls_ssl_context *ssl, struct iob *iob)
318 /* Computing length of buffer part to send */
319 long len = iob->eod - iob->cur;
326 /* Sending data to given SSl context */
327 if (ssl_send_data(ssl, (const unsigned char *)iob->cur, (size_t)len) < 0)
331 iob->eod = iob->cur = iob->buf;
336 /*********************************************************************
338 * Function : ssl_debug_callback
340 * Description : Debug callback function for mbedtls library.
341 * Prints info into log file.
344 * 1 : ctx = File to save log in
345 * 2 : level = Debug level
346 * 3 : file = File calling debug message
347 * 4 : line = Line calling debug message
348 * 5 : str = Debug message
352 *********************************************************************/
353 static void ssl_debug_callback(void *ctx, int level, const char *file, int line, const char *str)
357 fprintf((FILE *)ctx, "%s:%04d: %s", file, line, str);
359 log_error(LOG_LEVEL_INFO, "SSL debug message: %s:%04d: %s", file, line, str);
364 /*********************************************************************
366 * Function : create_client_ssl_connection
368 * Description : Creates TLS/SSL secured connection with client
371 * 1 : csp = Current client state (buffers, headers, etc...)
373 * Returns : 0 on success, negative value if connection wasn't created
376 *********************************************************************/
377 extern int create_client_ssl_connection(struct client_state *csp)
379 /* Paths to certificates file and key file */
380 char *key_file = NULL;
381 char *ca_file = NULL;
382 char *cert_file = NULL;
384 char err_buf[ERROR_BUF_SIZE];
387 * Initializing mbedtls structures for TLS/SSL connection
389 mbedtls_net_init(&(csp->mbedtls_client_attr.socket_fd));
390 mbedtls_ssl_init(&(csp->mbedtls_client_attr.ssl));
391 mbedtls_ssl_config_init(&(csp->mbedtls_client_attr.conf));
392 mbedtls_x509_crt_init(&(csp->mbedtls_client_attr.server_cert));
393 mbedtls_pk_init(&(csp->mbedtls_client_attr.prim_key));
394 #if defined(MBEDTLS_SSL_CACHE_C)
395 mbedtls_ssl_cache_init(&(csp->mbedtls_client_attr.cache));
399 * Preparing hash of host for creating certificates
401 ret = host_to_hash(csp);
404 log_error(LOG_LEVEL_ERROR, "Generating hash of host failed: %d", ret);
410 * Preparing paths to certificates files and key file
412 ca_file = csp->config->ca_cert_file;
413 cert_file = make_certs_path(csp->config->certificate_directory,
414 (const char *)csp->http->hash_of_host_hex, CERT_FILE_TYPE);
415 key_file = make_certs_path(csp->config->certificate_directory,
416 (const char *)csp->http->hash_of_host_hex, KEY_FILE_TYPE);
418 if (cert_file == NULL || key_file == NULL)
425 * Generating certificate for requested host. Mutex to prevent
426 * certificate and key inconsistence must be locked.
428 unsigned int cert_mutex_id = get_certificate_mutex_id(csp);
429 privoxy_mutex_lock(&(certificates_mutexes[cert_mutex_id]));
431 ret = generate_webpage_certificate(csp);
434 log_error(LOG_LEVEL_ERROR,
435 "Generate_webpage_certificate failed: %d", ret);
436 privoxy_mutex_unlock(&(certificates_mutexes[cert_mutex_id]));
440 privoxy_mutex_unlock(&(certificates_mutexes[cert_mutex_id]));
453 * Loading CA file, webpage certificate and key files
455 ret = mbedtls_x509_crt_parse_file(&(csp->mbedtls_client_attr.server_cert),
459 mbedtls_strerror(ret, err_buf, sizeof(err_buf));
460 log_error(LOG_LEVEL_ERROR,
461 "Loading webpage certificate %s failed: %s", cert_file, err_buf);
466 ret = mbedtls_x509_crt_parse_file(&(csp->mbedtls_client_attr.server_cert),
470 mbedtls_strerror(ret, err_buf, sizeof(err_buf));
471 log_error(LOG_LEVEL_ERROR,
472 "Loading CA certificate %s failed: %s", ca_file, err_buf);
477 ret = mbedtls_pk_parse_keyfile(&(csp->mbedtls_client_attr.prim_key),
481 mbedtls_strerror(ret, err_buf, sizeof(err_buf));
482 log_error(LOG_LEVEL_ERROR,
483 "Loading and parsing webpage certificate private key %s failed: %s",
490 * Setting SSL parameters
492 ret = mbedtls_ssl_config_defaults(&(csp->mbedtls_client_attr.conf),
493 MBEDTLS_SSL_IS_SERVER, MBEDTLS_SSL_TRANSPORT_STREAM,
494 MBEDTLS_SSL_PRESET_DEFAULT);
497 mbedtls_strerror(ret, err_buf, sizeof(err_buf));
498 log_error(LOG_LEVEL_ERROR,
499 "mbedtls_ssl_config_defaults failed: %s", err_buf);
504 mbedtls_ssl_conf_rng(&(csp->mbedtls_client_attr.conf),
505 mbedtls_ctr_drbg_random, &ctr_drbg);
506 mbedtls_ssl_conf_dbg(&(csp->mbedtls_client_attr.conf),
507 ssl_debug_callback, stdout);
509 #if defined(MBEDTLS_SSL_CACHE_C)
510 mbedtls_ssl_conf_session_cache(&(csp->mbedtls_client_attr.conf),
511 &(csp->mbedtls_client_attr.cache), mbedtls_ssl_cache_get,
512 mbedtls_ssl_cache_set);
516 * Setting certificates
518 ret = mbedtls_ssl_conf_own_cert(&(csp->mbedtls_client_attr.conf),
519 &(csp->mbedtls_client_attr.server_cert),
520 &(csp->mbedtls_client_attr.prim_key));
523 mbedtls_strerror(ret, err_buf, sizeof(err_buf));
524 log_error(LOG_LEVEL_ERROR,
525 "mbedtls_ssl_conf_own_cert failed: %s", err_buf);
530 ret = mbedtls_ssl_setup(&(csp->mbedtls_client_attr.ssl),
531 &(csp->mbedtls_client_attr.conf));
534 mbedtls_strerror(ret, err_buf, sizeof(err_buf));
535 log_error(LOG_LEVEL_ERROR, "mbedtls_ssl_setup failed: %s", err_buf);
540 mbedtls_ssl_set_bio(&(csp->mbedtls_client_attr.ssl),
541 &(csp->mbedtls_client_attr.socket_fd), mbedtls_net_send,
542 mbedtls_net_recv, NULL);
543 mbedtls_ssl_session_reset(&(csp->mbedtls_client_attr.ssl));
546 * Setting socket fd in mbedtls_net_context structure. This structure
547 * can't be set by mbedtls functions, because we already have created
548 * a TCP connection when this function is called.
550 csp->mbedtls_client_attr.socket_fd.fd = csp->cfd;
553 * Handshake with client
555 log_error(LOG_LEVEL_CONNECT,
556 "Performing the TLS/SSL handshake with client. Hash of host: %s",
557 csp->http->hash_of_host_hex);
558 while ((ret = mbedtls_ssl_handshake(&(csp->mbedtls_client_attr.ssl))) != 0)
560 if (ret != MBEDTLS_ERR_SSL_WANT_READ &&
561 ret != MBEDTLS_ERR_SSL_WANT_WRITE)
563 mbedtls_strerror(ret, err_buf, sizeof(err_buf));
564 log_error(LOG_LEVEL_ERROR,
565 "medtls_ssl_handshake with client failed: %s", err_buf);
571 log_error(LOG_LEVEL_CONNECT, "Client successfully connected over TLS/SSL");
572 csp->ssl_with_client_is_opened = 1;
576 * Freeing allocated paths to files
581 /* Freeing structures if connection wasn't created successfully */
584 free_client_ssl_structures(csp);
590 /*********************************************************************
592 * Function : close_client_ssl_connection
594 * Description : Closes TLS/SSL connection with client. This function
595 * checks if this connection is already created.
598 * 1 : csp = Current client state (buffers, headers, etc...)
602 *********************************************************************/
603 extern void close_client_ssl_connection(struct client_state *csp)
607 if (csp->ssl_with_client_is_opened == 0)
613 * Notifying the peer that the connection is being closed.
616 ret = mbedtls_ssl_close_notify(&(csp->mbedtls_client_attr.ssl));
617 } while (ret == MBEDTLS_ERR_SSL_WANT_WRITE);
619 free_client_ssl_structures(csp);
620 csp->ssl_with_client_is_opened = 0;
624 /*********************************************************************
626 * Function : free_client_ssl_structures
628 * Description : Frees structures used for SSL communication with
632 * 1 : csp = Current client state (buffers, headers, etc...)
636 *********************************************************************/
637 static void free_client_ssl_structures(struct client_state *csp)
640 * We can't use function mbedtls_net_free, because this function
641 * inter alia close TCP connection on setted fd. Instead of this
642 * function, we change fd to -1, which is the same what does
643 * rest of mbedtls_net_free function.
645 csp->mbedtls_client_attr.socket_fd.fd = -1;
647 /* Freeing mbedtls structures */
648 mbedtls_x509_crt_free(&(csp->mbedtls_client_attr.server_cert));
649 mbedtls_pk_free(&(csp->mbedtls_client_attr.prim_key));
650 mbedtls_ssl_free(&(csp->mbedtls_client_attr.ssl));
651 mbedtls_ssl_config_free(&(csp->mbedtls_client_attr.conf));
652 #if defined(MBEDTLS_SSL_CACHE_C)
653 mbedtls_ssl_cache_free(&(csp->mbedtls_client_attr.cache));
658 /*********************************************************************
660 * Function : create_server_ssl_connection
662 * Description : Creates TLS/SSL secured connection with server.
665 * 1 : csp = Current client state (buffers, headers, etc...)
667 * Returns : 0 on success, negative value if connection wasn't created
670 *********************************************************************/
671 extern int create_server_ssl_connection(struct client_state *csp)
674 char err_buf[ERROR_BUF_SIZE];
675 char *trusted_cas_file = NULL;
676 int auth_mode = MBEDTLS_SSL_VERIFY_REQUIRED;
678 csp->server_cert_verification_result = SSL_CERT_NOT_VERIFIED;
679 csp->server_certs_chain.next = NULL;
681 /* Setting path to file with trusted CAs */
682 trusted_cas_file = csp->config->trusted_cas_file;
685 * Initializing mbedtls structures for TLS/SSL connection
687 mbedtls_net_init(&(csp->mbedtls_server_attr.socket_fd));
688 mbedtls_ssl_init(&(csp->mbedtls_server_attr.ssl));
689 mbedtls_ssl_config_init(&(csp->mbedtls_server_attr.conf));
690 mbedtls_x509_crt_init(&(csp->mbedtls_server_attr.ca_cert));
693 * Setting socket fd in mbedtls_net_context structure. This structure
694 * can't be set by mbedtls functions, because we already have created
695 * TCP connection when calling this function.
697 csp->mbedtls_server_attr.socket_fd.fd = csp->server_connection.sfd;
710 * Loading file with trusted CAs
712 ret = mbedtls_x509_crt_parse_file(&(csp->mbedtls_server_attr.ca_cert),
716 mbedtls_strerror(ret, err_buf, sizeof(err_buf));
717 log_error(LOG_LEVEL_ERROR, "Loading trusted CAs file %s failed: %s",
718 trusted_cas_file, err_buf);
724 * Set TLS/SSL options
726 ret = mbedtls_ssl_config_defaults(&(csp->mbedtls_server_attr.conf),
727 MBEDTLS_SSL_IS_CLIENT,
728 MBEDTLS_SSL_TRANSPORT_STREAM,
729 MBEDTLS_SSL_PRESET_DEFAULT);
732 mbedtls_strerror(ret, err_buf, sizeof(err_buf));
733 log_error(LOG_LEVEL_ERROR, "mbedtls_ssl_config_defaults failed: %s",
740 * Setting how strict should certificate verification be and other
741 * parameters for certificate verification
743 if (csp->dont_verify_certificate)
745 auth_mode = MBEDTLS_SSL_VERIFY_NONE;
748 mbedtls_ssl_conf_authmode(&(csp->mbedtls_server_attr.conf), auth_mode);
749 mbedtls_ssl_conf_ca_chain(&(csp->mbedtls_server_attr.conf),
750 &(csp->mbedtls_server_attr.ca_cert), NULL);
752 /* Setting callback function for certificates verification */
753 mbedtls_ssl_conf_verify(&(csp->mbedtls_server_attr.conf),
754 ssl_verify_callback, (void *)csp);
756 mbedtls_ssl_conf_rng(&(csp->mbedtls_server_attr.conf),
757 mbedtls_ctr_drbg_random, &ctr_drbg);
758 mbedtls_ssl_conf_dbg(&(csp->mbedtls_server_attr.conf),
759 ssl_debug_callback, stdout);
761 ret = mbedtls_ssl_setup(&(csp->mbedtls_server_attr.ssl),
762 &(csp->mbedtls_server_attr.conf));
765 mbedtls_strerror(ret, err_buf, sizeof(err_buf));
766 log_error(LOG_LEVEL_ERROR, "mbedtls_ssl_setup failed: %s", err_buf);
772 * Set the hostname to check against the received server certificate
774 ret = mbedtls_ssl_set_hostname(&(csp->mbedtls_server_attr.ssl),
778 mbedtls_strerror(ret, err_buf, sizeof(err_buf));
779 log_error(LOG_LEVEL_ERROR, "mbedtls_ssl_set_hostname failed: %s",
785 mbedtls_ssl_set_bio(&(csp->mbedtls_server_attr.ssl),
786 &(csp->mbedtls_server_attr.socket_fd), mbedtls_net_send,
787 mbedtls_net_recv, NULL);
790 * Handshake with server
792 log_error(LOG_LEVEL_CONNECT,
793 "Performing the TLS/SSL handshake with server");
795 while ((ret = mbedtls_ssl_handshake(&(csp->mbedtls_server_attr.ssl))) != 0)
797 if (ret != MBEDTLS_ERR_SSL_WANT_READ
798 && ret != MBEDTLS_ERR_SSL_WANT_WRITE)
800 mbedtls_strerror(ret, err_buf, sizeof(err_buf));
802 if (ret == MBEDTLS_ERR_X509_CERT_VERIFY_FAILED)
804 log_error(LOG_LEVEL_ERROR,
805 "Server certificate verification failed: %s", err_buf);
806 csp->server_cert_verification_result =
807 mbedtls_ssl_get_verify_result(&(csp->mbedtls_server_attr.ssl));
813 log_error(LOG_LEVEL_ERROR,
814 "mbedtls_ssl_handshake with server failed: %s", err_buf);
821 log_error(LOG_LEVEL_CONNECT, "Server successfully connected over TLS/SSL");
824 * Server certificate chain is valid, so we can clean
825 * chain, because we will not send it to client.
827 free_certificate_chain(csp);
829 csp->ssl_with_server_is_opened = 1;
830 csp->server_cert_verification_result =
831 mbedtls_ssl_get_verify_result(&(csp->mbedtls_server_attr.ssl));
834 /* Freeing structures if connection wasn't created successfully */
837 free_server_ssl_structures(csp);
844 /*********************************************************************
846 * Function : close_server_ssl_connection
848 * Description : Closes TLS/SSL connection with server. This function
849 * checks if this connection is already opened.
852 * 1 : csp = Current client state (buffers, headers, etc...)
856 *********************************************************************/
857 static void close_server_ssl_connection(struct client_state *csp)
861 if (csp->ssl_with_server_is_opened == 0)
867 * Notifying the peer that the connection is being closed.
870 ret = mbedtls_ssl_close_notify(&(csp->mbedtls_server_attr.ssl));
871 } while (ret == MBEDTLS_ERR_SSL_WANT_WRITE);
873 free_server_ssl_structures(csp);
874 csp->ssl_with_server_is_opened = 0;
878 /*********************************************************************
880 * Function : free_server_ssl_structures
882 * Description : Frees structures used for SSL communication with server
885 * 1 : csp = Current client state (buffers, headers, etc...)
889 *********************************************************************/
890 static void free_server_ssl_structures(struct client_state *csp)
893 * We can't use function mbedtls_net_free, because this function
894 * inter alia close TCP connection on setted fd. Instead of this
895 * function, we change fd to -1, which is the same what does
896 * rest of mbedtls_net_free function.
898 csp->mbedtls_client_attr.socket_fd.fd = -1;
900 mbedtls_x509_crt_free(&(csp->mbedtls_server_attr.ca_cert));
901 mbedtls_ssl_free(&(csp->mbedtls_server_attr.ssl));
902 mbedtls_ssl_config_free(&(csp->mbedtls_server_attr.conf));
906 /*********************************************************************
908 * Function : close_client_and_server_ssl_connections
910 * Description : Checks if client or server should use secured
911 * connection over SSL and if so, closes all of them.
914 * 1 : csp = Current client state (buffers, headers, etc...)
918 *********************************************************************/
919 extern void close_client_and_server_ssl_connections(struct client_state *csp)
921 if (client_use_ssl(csp) == 1)
923 close_client_ssl_connection(csp);
925 if (server_use_ssl(csp) == 1)
927 close_server_ssl_connection(csp);
931 /*====================== Certificates ======================*/
933 /*********************************************************************
935 * Function : write_certificate
937 * Description : Writes certificate into file.
940 * 1 : crt = certificate to write into file
941 * 2 : output_file = path to save certificate file
942 * 3 : f_rng = mbedtls_ctr_drbg_random
943 * 4 : p_rng = mbedtls_ctr_drbg_context
945 * Returns : Length of written certificate on success or negative value
948 *********************************************************************/
949 static int write_certificate(mbedtls_x509write_cert *crt, const char *output_file,
950 int(*f_rng)(void *, unsigned char *, size_t), void *p_rng)
954 unsigned char cert_buf[CERTIFICATE_BUF_SIZE + 1]; /* Buffer for certificate in PEM format + terminating NULL */
956 char err_buf[ERROR_BUF_SIZE];
958 memset(cert_buf, 0, sizeof(cert_buf));
961 * Writing certificate into PEM string. If buffer is too small, function
962 * returns specific error and no buffer overflow can happen.
964 if ((ret = mbedtls_x509write_crt_pem(crt, cert_buf,
965 sizeof(cert_buf) - 1, f_rng, p_rng)) != 0)
967 mbedtls_strerror(ret, err_buf, sizeof(err_buf));
968 log_error(LOG_LEVEL_ERROR,
969 "Writing certificate into buffer failed: %s", err_buf);
973 len = strlen((char *)cert_buf);
976 * Saving certificate into file
978 if ((f = fopen(output_file, "w")) == NULL)
980 log_error(LOG_LEVEL_ERROR, "Opening file %s to save certificate failed",
985 if (fwrite(cert_buf, 1, len, f) != len)
987 log_error(LOG_LEVEL_ERROR,
988 "Writing certificate into file %s failed", output_file);
999 /*********************************************************************
1001 * Function : write_private_key
1003 * Description : Writes private key into file and copies saved
1004 * content into given pointer to string. If function
1005 * returns 0 for success, this copy must be freed by
1009 * 1 : key = key to write into file
1010 * 2 : ret_buf = pointer to string with created key file content
1011 * 3 : key_file_path = path where to save key file
1013 * Returns : Length of written private key on success or negative value
1016 *********************************************************************/
1017 static int write_private_key(mbedtls_pk_context *key, unsigned char **ret_buf,
1018 const char *key_file_path)
1020 size_t len = 0; /* Length of created key */
1021 FILE *f = NULL; /* File to save certificate */
1023 char err_buf[ERROR_BUF_SIZE];
1025 /* Initializing buffer for key file content */
1026 *ret_buf = zalloc_or_die(PRIVATE_KEY_BUF_SIZE + 1);
1029 * Writing private key into PEM string
1031 if ((ret = mbedtls_pk_write_key_pem(key, *ret_buf, PRIVATE_KEY_BUF_SIZE)) != 0)
1033 mbedtls_strerror(ret, err_buf, sizeof(err_buf));
1034 log_error(LOG_LEVEL_ERROR,
1035 "Writing private key into PEM string failed: %s", err_buf);
1039 len = strlen((char *)*ret_buf);
1042 * Saving key into file
1044 if ((f = fopen(key_file_path, "wb")) == NULL)
1046 log_error(LOG_LEVEL_ERROR,
1047 "Opening file %s to save private key failed: %E",
1053 if (fwrite(*ret_buf, 1, len, f) != len)
1056 log_error(LOG_LEVEL_ERROR,
1057 "Writing private key into file %s failed",
1076 /*********************************************************************
1078 * Function : generate_key
1080 * Description : Tests if private key for host saved in csp already
1081 * exists. If this file doesn't exists, a new key is
1082 * generated and saved in a file. The generated key is also
1083 * copied into given parameter key_buf, which must be then
1084 * freed by caller. If file with key exists, key_buf
1085 * contain NULL and no private key is generated.
1088 * 1 : key_buf = buffer to save new generated key
1089 * 2 : csp = Current client state (buffers, headers, etc...)
1091 * Returns : -1 => Error while generating private key
1092 * 0 => Key already exists
1093 * >0 => Length of generated private key
1095 *********************************************************************/
1096 static int generate_key(unsigned char **key_buf, struct client_state *csp)
1098 mbedtls_pk_context key;
1099 key_options key_opt;
1101 char err_buf[ERROR_BUF_SIZE];
1103 key_opt.key_file_path = NULL;
1106 * Initializing structures for key generating
1108 mbedtls_pk_init(&key);
1111 * Preparing path for key file and other properties for generating key
1113 key_opt.type = MBEDTLS_PK_RSA;
1114 key_opt.rsa_keysize = RSA_KEYSIZE;
1116 key_opt.key_file_path = make_certs_path(csp->config->certificate_directory,
1117 (char *)csp->http->hash_of_host_hex, KEY_FILE_TYPE);
1118 if (key_opt.key_file_path == NULL)
1125 * Test if key already exists. If so, we don't have to create it again.
1127 if (file_exists(key_opt.key_file_path) == 1)
1136 ret = seed_rng(csp);
1144 * Setting attributes of private key and generating it
1146 if ((ret = mbedtls_pk_setup(&key,
1147 mbedtls_pk_info_from_type(key_opt.type))) != 0)
1149 mbedtls_strerror(ret, err_buf, sizeof(err_buf));
1150 log_error(LOG_LEVEL_ERROR, "mbedtls_pk_setup failed: %s", err_buf);
1155 ret = mbedtls_rsa_gen_key(mbedtls_pk_rsa(key), mbedtls_ctr_drbg_random,
1156 &ctr_drbg, (unsigned)key_opt.rsa_keysize, RSA_KEY_PUBLIC_EXPONENT);
1159 mbedtls_strerror(ret, err_buf, sizeof(err_buf));
1160 log_error(LOG_LEVEL_ERROR, "Key generating failed: %s", err_buf);
1166 * Exporting private key into file
1168 if ((ret = write_private_key(&key, key_buf, key_opt.key_file_path)) < 0)
1170 log_error(LOG_LEVEL_ERROR,
1171 "Writing private key into file %s failed", key_opt.key_file_path);
1178 * Freeing used variables
1180 freez(key_opt.key_file_path);
1182 mbedtls_pk_free(&key);
1188 /*********************************************************************
1190 * Function : generate_webpage_certificate
1192 * Description : Creates certificate file in presetted directory.
1193 * If certificate already exists, no other certificate
1194 * will be created. Subject of certificate is named
1195 * by csp->http->host from parameter. This function also
1196 * triggers generating of private key for new certificate.
1199 * 1 : csp = Current client state (buffers, headers, etc...)
1201 * Returns : -1 => Error while creating certificate.
1202 * 0 => Certificate already exists.
1203 * >0 => Length of created certificate.
1205 *********************************************************************/
1206 static int generate_webpage_certificate(struct client_state *csp)
1208 mbedtls_x509_crt issuer_cert;
1209 mbedtls_pk_context loaded_issuer_key, loaded_subject_key;
1210 mbedtls_pk_context *issuer_key = &loaded_issuer_key;
1211 mbedtls_pk_context *subject_key = &loaded_subject_key;
1212 mbedtls_x509write_cert cert;
1215 unsigned char *key_buf = NULL; /* Buffer for created key */
1218 char err_buf[ERROR_BUF_SIZE];
1219 cert_options cert_opt;
1221 /* Paths to keys and certificates needed to create certificate */
1222 cert_opt.issuer_key = NULL;
1223 cert_opt.subject_key = NULL;
1224 cert_opt.issuer_crt = NULL;
1225 cert_opt.output_file = NULL;
1228 * Create key for requested host
1230 int subject_key_len = generate_key(&key_buf, csp);
1231 if (subject_key_len < 0)
1233 log_error(LOG_LEVEL_ERROR, "Key generating failed");
1238 * Initializing structures for certificate generating
1240 mbedtls_x509write_crt_init(&cert);
1241 mbedtls_x509write_crt_set_md_alg(&cert, CERT_SIGNATURE_ALGORITHM);
1242 mbedtls_pk_init(&loaded_issuer_key);
1243 mbedtls_pk_init(&loaded_subject_key);
1244 mbedtls_mpi_init(&serial);
1245 mbedtls_x509_crt_init(&issuer_cert);
1248 * Presetting parameters for certificate. We must compute total length
1251 size_t cert_params_len = strlen(CERT_PARAM_COMMON_NAME) +
1252 strlen(CERT_PARAM_ORGANIZATION) + strlen(CERT_PARAM_COUNTRY) +
1253 strlen(CERT_PARAM_ORG_UNIT) +
1254 3 * strlen(csp->http->host) + 1;
1255 char cert_params[cert_params_len];
1256 memset(cert_params, 0, cert_params_len);
1259 * Converting unsigned long serial number to char * serial number.
1260 * We must compute length of serial number in string + terminating null.
1262 unsigned long certificate_serial = get_certificate_serial(csp);
1263 int serial_num_size = snprintf(NULL, 0, "%lu", certificate_serial) + 1;
1264 if (serial_num_size <= 0)
1266 serial_num_size = 1;
1269 char serial_num_text[serial_num_size]; /* Buffer for serial number */
1270 ret = snprintf(serial_num_text, (size_t)serial_num_size, "%lu", certificate_serial);
1271 if (ret < 0 || ret >= serial_num_size)
1273 log_error(LOG_LEVEL_ERROR,
1274 "Converting certificate serial number into string failed");
1280 * Preparing parameters for certificate
1282 strlcpy(cert_params, CERT_PARAM_COMMON_NAME, cert_params_len);
1283 strlcat(cert_params, csp->http->host, cert_params_len);
1284 strlcat(cert_params, CERT_PARAM_ORGANIZATION, cert_params_len);
1285 strlcat(cert_params, csp->http->host, cert_params_len);
1286 strlcat(cert_params, CERT_PARAM_ORG_UNIT, cert_params_len);
1287 strlcat(cert_params, csp->http->host, cert_params_len);
1288 strlcat(cert_params, CERT_PARAM_COUNTRY, cert_params_len);
1290 cert_opt.issuer_crt = csp->config->ca_cert_file;
1291 cert_opt.issuer_key = csp->config->ca_key_file;
1292 cert_opt.subject_key = make_certs_path(csp->config->certificate_directory,
1293 (const char *)csp->http->hash_of_host_hex, KEY_FILE_TYPE);
1294 cert_opt.output_file = make_certs_path(csp->config->certificate_directory,
1295 (const char *)csp->http->hash_of_host_hex, CERT_FILE_TYPE);
1297 if (cert_opt.subject_key == NULL || cert_opt.output_file == NULL)
1303 cert_opt.subject_pwd = CERT_SUBJECT_PASSWORD;
1304 cert_opt.issuer_pwd = csp->config->ca_password;
1305 cert_opt.subject_name = cert_params;
1306 cert_opt.not_before = GENERATED_CERT_VALID_FROM;
1307 cert_opt.not_after = GENERATED_CERT_VALID_TO;
1308 cert_opt.serial = serial_num_text;
1310 cert_opt.max_pathlen = -1;
1313 * Test if certificate exists and private key was already created
1315 if (file_exists(cert_opt.output_file) == 1 && subject_key_len == 0)
1324 ret = seed_rng(csp);
1332 * Parse serial to MPI
1334 ret = mbedtls_mpi_read_string(&serial, 10, cert_opt.serial);
1337 mbedtls_strerror(ret, err_buf, sizeof(err_buf));
1338 log_error(LOG_LEVEL_ERROR,
1339 "mbedtls_mpi_read_string failed: %s", err_buf);
1345 * Loading certificates
1347 ret = mbedtls_x509_crt_parse_file(&issuer_cert, cert_opt.issuer_crt);
1350 mbedtls_strerror(ret, err_buf, sizeof(err_buf));
1351 log_error(LOG_LEVEL_ERROR, "Loading issuer certificate %s failed: %s",
1352 cert_opt.issuer_crt, err_buf);
1357 ret = mbedtls_x509_dn_gets(cert_opt.issuer_name,
1358 sizeof(cert_opt.issuer_name), &issuer_cert.subject);
1361 mbedtls_strerror(ret, err_buf, sizeof(err_buf));
1362 log_error(LOG_LEVEL_ERROR, "mbedtls_x509_dn_gets failed: %s", err_buf);
1368 * Loading keys from file or from buffer
1370 if (key_buf != NULL && subject_key_len > 0)
1372 /* Key was created in this function and is stored in buffer */
1373 ret = mbedtls_pk_parse_key(&loaded_subject_key, key_buf,
1374 (size_t)(subject_key_len + 1), (unsigned const char *)
1375 cert_opt.subject_pwd, strlen(cert_opt.subject_pwd));
1379 /* Key wasn't created in this function, because it already existed */
1380 ret = mbedtls_pk_parse_keyfile(&loaded_subject_key,
1381 cert_opt.subject_key, cert_opt.subject_pwd);
1386 mbedtls_strerror(ret, err_buf, sizeof(err_buf));
1387 log_error(LOG_LEVEL_ERROR, "Parsing subject key %s failed: %s",
1388 cert_opt.subject_key, err_buf);
1393 ret = mbedtls_pk_parse_keyfile(&loaded_issuer_key, cert_opt.issuer_key,
1394 cert_opt.issuer_pwd);
1397 mbedtls_strerror(ret, err_buf, sizeof(err_buf));
1398 log_error(LOG_LEVEL_ERROR,
1399 "Parsing issuer key %s failed: %s", cert_opt.issuer_key, err_buf);
1405 * Check if key and issuer certificate match
1407 if (!mbedtls_pk_can_do(&issuer_cert.pk, MBEDTLS_PK_RSA) ||
1408 mbedtls_mpi_cmp_mpi(&mbedtls_pk_rsa(issuer_cert.pk)->N,
1409 &mbedtls_pk_rsa(*issuer_key)->N) != 0 ||
1410 mbedtls_mpi_cmp_mpi(&mbedtls_pk_rsa(issuer_cert.pk)->E,
1411 &mbedtls_pk_rsa(*issuer_key)->E) != 0)
1413 log_error(LOG_LEVEL_ERROR,
1414 "Issuer key doesn't match issuer certificate");
1419 mbedtls_x509write_crt_set_subject_key(&cert, subject_key);
1420 mbedtls_x509write_crt_set_issuer_key(&cert, issuer_key);
1423 * Setting parameters of signed certificate
1425 ret = mbedtls_x509write_crt_set_subject_name(&cert, cert_opt.subject_name);
1428 mbedtls_strerror(ret, err_buf, sizeof(err_buf));
1429 log_error(LOG_LEVEL_ERROR,
1430 "Setting subject name in signed certificate failed: %s", err_buf);
1435 ret = mbedtls_x509write_crt_set_issuer_name(&cert, cert_opt.issuer_name);
1438 mbedtls_strerror(ret, err_buf, sizeof(err_buf));
1439 log_error(LOG_LEVEL_ERROR,
1440 "Setting issuer name in signed certificate failed: %s", err_buf);
1445 ret = mbedtls_x509write_crt_set_serial(&cert, &serial);
1448 mbedtls_strerror(ret, err_buf, sizeof(err_buf));
1449 log_error(LOG_LEVEL_ERROR,
1450 "Setting serial number in signed certificate failed: %s", err_buf);
1455 ret = mbedtls_x509write_crt_set_validity(&cert, cert_opt.not_before,
1456 cert_opt.not_after);
1459 mbedtls_strerror(ret, err_buf, sizeof(err_buf));
1460 log_error(LOG_LEVEL_ERROR,
1461 "Setting validity in signed certificate failed: %s", err_buf);
1467 * Setting the basicConstraints extension for certificate
1469 ret = mbedtls_x509write_crt_set_basic_constraints(&cert, cert_opt.is_ca,
1470 cert_opt.max_pathlen);
1473 mbedtls_strerror(ret, err_buf, sizeof(err_buf));
1474 log_error(LOG_LEVEL_ERROR, "Setting the basicConstraints extension "
1475 "in signed certificate failed: %s", err_buf);
1480 #if defined(MBEDTLS_SHA1_C)
1481 /* Setting the subjectKeyIdentifier extension for certificate */
1482 ret = mbedtls_x509write_crt_set_subject_key_identifier(&cert);
1485 mbedtls_strerror(ret, err_buf, sizeof(err_buf));
1486 log_error(LOG_LEVEL_ERROR, "mbedtls_x509write_crt_set_subject_key_"
1487 "identifier failed: %s", err_buf);
1492 /* Setting the authorityKeyIdentifier extension for certificate */
1493 ret = mbedtls_x509write_crt_set_authority_key_identifier(&cert);
1496 mbedtls_strerror(ret, err_buf, sizeof(err_buf));
1497 log_error(LOG_LEVEL_ERROR, "mbedtls_x509write_crt_set_authority_key_"
1498 "identifier failed: %s", err_buf);
1502 #endif /* MBEDTLS_SHA1_C */
1505 * Writing certificate into file
1507 ret = write_certificate(&cert, cert_opt.output_file,
1508 mbedtls_ctr_drbg_random, &ctr_drbg);
1511 log_error(LOG_LEVEL_ERROR, "Writing certificate into file failed");
1517 * Freeing used structures
1519 mbedtls_x509write_crt_free(&cert);
1520 mbedtls_pk_free(&loaded_subject_key);
1521 mbedtls_pk_free(&loaded_issuer_key);
1522 mbedtls_mpi_free(&serial);
1523 mbedtls_x509_crt_free(&issuer_cert);
1525 freez(cert_opt.subject_key);
1526 freez(cert_opt.output_file);
1533 /*********************************************************************
1535 * Function : make_certs_path
1537 * Description : Creates path to file from three pieces. This fuction
1538 * takes parameters and puts them in one new mallocated
1539 * char * in correct order. Returned variable must be freed
1540 * by caller. This function is mainly used for creating
1541 * paths of certificates and keys files.
1544 * 1 : conf_dir = Name/path of directory where is the file.
1545 * '.' can be used for current directory.
1546 * 2 : file_name = Name of file in conf_dir without suffix.
1547 * 3 : suffix = Suffix of given file_name.
1549 * Returns : path => Path was built up successfully
1550 * NULL => Path can't be built up
1552 *********************************************************************/
1553 static char *make_certs_path(const char *conf_dir, const char *file_name,
1556 /* Test if all given parameters are valid */
1557 if (conf_dir == NULL || *conf_dir == '\0' || file_name == NULL ||
1558 *file_name == '\0' || suffix == NULL || *suffix == '\0')
1560 log_error(LOG_LEVEL_ERROR,
1561 "make_certs_path failed: bad input parameters");
1566 size_t path_size = strlen(conf_dir)
1567 + strlen(file_name) + strlen(suffix) + 2;
1569 /* Setting delimiter and editing path length */
1570 #if defined(_WIN32) || defined(__OS2__)
1571 char delim[] = "\\";
1573 #else /* ifndef _WIN32 || __OS2__ */
1575 #endif /* ifndef _WIN32 || __OS2__ */
1578 * Building up path from many parts
1581 if (*conf_dir != '/' && basedir && *basedir)
1584 * Replacing conf_dir with basedir. This new variable contains
1585 * absolute path to cwd.
1587 path_size += strlen(basedir) + 2;
1588 path = zalloc_or_die(path_size);
1590 strlcpy(path, basedir, path_size);
1591 strlcat(path, delim, path_size);
1592 strlcat(path, conf_dir, path_size);
1593 strlcat(path, delim, path_size);
1594 strlcat(path, file_name, path_size);
1595 strlcat(path, suffix, path_size);
1598 #endif /* defined unix */
1600 path = zalloc_or_die(path_size);
1602 strlcpy(path, conf_dir, path_size);
1603 strlcat(path, delim, path_size);
1604 strlcat(path, file_name, path_size);
1605 strlcat(path, suffix, path_size);
1612 /*********************************************************************
1614 * Function : get_certificate_mutex_id
1616 * Description : Computes mutex id from host name hash. This hash must
1617 * be already saved in csp structure
1620 * 1 : csp = Current client state (buffers, headers, etc...)
1622 * Returns : Mutex id for given host name
1624 *********************************************************************/
1625 static unsigned int get_certificate_mutex_id(struct client_state *csp) {
1626 #ifdef LIMIT_MUTEX_NUMBER
1627 return (unsigned int)(csp->http->hash_of_host[0] % 32);
1629 return (unsigned int)(csp->http->hash_of_host[1]
1630 + 256 * (int)csp->http->hash_of_host[0]);
1631 #endif /* LIMIT_MUTEX_NUMBER */
1635 /*********************************************************************
1637 * Function : get_certificate_serial
1639 * Description : Computes serial number for new certificate from host
1640 * name hash. This hash must be already saved in csp
1644 * 1 : csp = Current client state (buffers, headers, etc...)
1646 * Returns : Serial number for new certificate
1648 *********************************************************************/
1649 static unsigned long get_certificate_serial(struct client_state *csp) {
1650 unsigned long exp = 1;
1651 unsigned long serial = 0;
1653 int i = CERT_SERIAL_NUM_LENGTH;
1654 /* Length of hash is 16 bytes, we must avoid to read next chars */
1666 serial += exp * (unsigned)csp->http->hash_of_host[i];
1673 /*********************************************************************
1675 * Function : ssl_send_certificate_error
1677 * Description : Sends info about invalid server certificate to client.
1678 * Sent message is including all trusted chain certificates,
1679 * that can be downloaded in web browser.
1682 * 1 : csp = Current client state (buffers, headers, etc...)
1686 *********************************************************************/
1687 extern void ssl_send_certificate_error(struct client_state *csp)
1689 size_t message_len = 0;
1691 struct certs_chain *cert = NULL;
1693 /* Header of message with certificate informations */
1694 const char message_begin[] =
1695 "HTTP/1.1 200 OK\r\n"
1696 "Content-Type: text/html\r\n"
1697 "Connection: close\r\n\r\n"
1698 "<html><body><h1>Invalid server certificate</h1><p>Reason: ";
1699 const char message_end[] = "</body></html>\r\n\r\n";
1700 char reason[INVALID_CERT_INFO_BUF_SIZE];
1701 memset(reason, 0, sizeof(reason));
1703 /* Get verification message from verification return code */
1704 mbedtls_x509_crt_verify_info(reason, sizeof(reason), " ",
1705 csp->server_cert_verification_result);
1708 * Computing total length of message with all certificates inside
1710 message_len = strlen(message_begin) + strlen(message_end)
1711 + strlen(reason) + strlen("</p>") + 1;
1713 cert = &(csp->server_certs_chain);
1714 while (cert->next != NULL)
1716 size_t base64_len = 4 * ((strlen(cert->file_buf) + 2) / 3) + 1;
1718 message_len += strlen(cert->text_buf) + strlen("<pre></pre>\n")
1719 + base64_len + strlen("<a href=\"data:application"
1720 "/x-x509-ca-cert;base64,\">Download certificate</a>");
1725 * Joining all blocks in one long message
1727 char message[message_len];
1728 memset(message, 0, message_len);
1730 strlcpy(message, message_begin, message_len);
1731 strlcat(message, reason , message_len);
1732 strlcat(message, "</p>" , message_len);
1734 cert = &(csp->server_certs_chain);
1735 while (cert->next != NULL)
1738 size_t base64_len = 4 * ((strlen(cert->file_buf) + 2) / 3) + 1; /* +1 for terminating null*/
1739 char base64_buf[base64_len];
1740 memset(base64_buf, 0, base64_len);
1742 /* Encoding certificate into base64 code */
1743 ret = mbedtls_base64_encode((unsigned char*)base64_buf,
1744 base64_len, &olen, (const unsigned char*)cert->file_buf,
1745 strlen(cert->file_buf));
1748 log_error(LOG_LEVEL_ERROR,
1749 "Encoding to base64 failed, buffer is to small");
1752 strlcat(message, "<pre>", message_len);
1753 strlcat(message, cert->text_buf, message_len);
1754 strlcat(message, "</pre>\n", message_len);
1758 strlcat(message, "<a href=\"data:application/x-x509-ca-cert;base64,",
1760 strlcat(message, base64_buf, message_len);
1761 strlcat(message, "\">Download certificate</a>", message_len);
1766 strlcat(message, message_end, message_len);
1769 * Sending final message to client
1771 ssl_send_data(&(csp->mbedtls_client_attr.ssl),
1772 (const unsigned char *)message, strlen(message));
1774 * Waiting before closing connection. Some browsers don't show received
1775 * message if there isn't this delay.
1779 free_certificate_chain(csp);
1783 /*********************************************************************
1785 * Function : ssl_verify_callback
1787 * Description : This is a callback function for certificate verification.
1788 * It's called for all certificates in server certificate
1789 * trusted chain and it's preparing information about this
1790 * certificates. Prepared informations can be used to inform
1791 * user about invalid certificates.
1794 * 1 : csp_void = Current client state (buffers, headers, etc...)
1795 * 2 : crt = certificate from trusted chain
1796 * 3 : depth = depth in trusted chain
1797 * 4 : flags = certificate flags
1799 * Returns : 0 on success and negative value on error
1801 *********************************************************************/
1802 static int ssl_verify_callback(void *csp_void, mbedtls_x509_crt *crt,
1803 int depth, uint32_t *flags)
1805 struct client_state *csp = (struct client_state *)csp_void;
1806 struct certs_chain *last = &(csp->server_certs_chain);
1811 * Searching for last item in certificates linked list
1813 while (last->next != NULL)
1819 * Preparing next item in linked list for next certificate
1821 last->next = malloc_or_die(sizeof(struct certs_chain));
1822 last->next->next = NULL;
1823 memset(last->next->text_buf, 0, sizeof(last->next->text_buf));
1824 memset(last->next->file_buf, 0, sizeof(last->next->file_buf));
1827 * Saving certificate file into buffer
1829 if ((ret = mbedtls_pem_write_buffer(PEM_BEGIN_CRT, PEM_END_CRT,
1830 crt->raw.p, crt->raw.len, (unsigned char *)last->file_buf,
1831 sizeof(last->file_buf)-1, &olen)) != 0)
1837 * Saving certificate information into buffer
1839 mbedtls_x509_crt_info(last->text_buf, sizeof(last->text_buf) - 1,
1840 CERT_INFO_PREFIX, crt);
1846 /*********************************************************************
1848 * Function : free_certificate_chain
1850 * Description : Frees certificates linked list. This linked list is
1851 * used to save informations about certificates in
1855 * 1 : csp = Current client state (buffers, headers, etc...)
1859 *********************************************************************/
1860 static void free_certificate_chain(struct client_state *csp)
1862 struct certs_chain *cert = csp->server_certs_chain.next;
1864 /* Cleaning buffers */
1865 memset(csp->server_certs_chain.text_buf, 0,
1866 sizeof(csp->server_certs_chain.text_buf));
1867 memset(csp->server_certs_chain.file_buf, 0,
1868 sizeof(csp->server_certs_chain.file_buf));
1869 csp->server_certs_chain.next = NULL;
1871 /* Freeing memory in whole linked list */
1876 struct certs_chain *cert_for_free = cert;
1878 freez(cert_for_free);
1879 } while (cert != NULL);
1884 /*********************************************************************
1886 * Function : file_exists
1888 * Description : Tests if file exists and is readable.
1891 * 1 : path = Path to tested file.
1893 * Returns : 1 => File exists and is readable.
1894 * 0 => File doesn't exist or is not readable.
1896 *********************************************************************/
1897 static int file_exists(const char *path)
1900 if ((f = fopen(path, "r")) != NULL)
1910 /*********************************************************************
1912 * Function : host_to_hash
1914 * Description : Creates MD5 hash from host name. Host name is loaded
1915 * from structure csp and saved again into it.
1918 * 1 : csp = Current client state (buffers, headers, etc...)
1920 * Returns : 1 => Error while creating hash
1921 * 0 => Hash created successfully
1923 *********************************************************************/
1924 static int host_to_hash(struct client_state *csp)
1928 #if !defined(MBEDTLS_MD5_C)
1929 log_error(LOG_LEVEL_ERROR, "MBEDTLS_MD5_C is not defined. Can't create"
1930 "MD5 hash for certificate and key name.");
1933 memset(csp->http->hash_of_host, 0, sizeof(csp->http->hash_of_host));
1934 mbedtls_md5((unsigned char *)csp->http->host, strlen(csp->http->host),
1935 csp->http->hash_of_host);
1937 /* Converting hash into string with hex */
1941 if ((ret = sprintf((char *)csp->http->hash_of_host_hex + 2 * i, "%02x",
1942 csp->http->hash_of_host[i])) < 0)
1944 log_error(LOG_LEVEL_ERROR, "Sprintf return value: %d", ret);
1950 #endif /* MBEDTLS_MD5_C */
1954 /*********************************************************************
1956 * Function : tunnel_established_successfully
1958 * Description : Check if parent proxy server response contains
1959 * informations about successfully created connection with
1960 * destination server. (HTTP/... 2xx ...)
1963 * 1 : server_response = Buffer with parent proxy server response
1964 * 2 : response_len = Length of server_response
1966 * Returns : 1 => Connection created successfully
1967 * 0 => Connection wasn't created successfully
1969 *********************************************************************/
1970 extern int tunnel_established_successfully(const char *server_response,
1971 unsigned int response_len)
1973 unsigned int pos = 0;
1975 if (server_response == NULL)
1980 /* Tests if "HTTP/" string is at the begin of received response */
1981 if (strncmp(server_response, "HTTP/", 5) != 0)
1986 for (pos = 0; pos < response_len; pos++)
1988 if (server_response[pos] == ' ')
1995 * response_len -3 because of buffer end, response structure and 200 code.
1996 * There must be at least 3 chars after space.
1997 * End of buffer: ... 2xx'\0'
2000 if (pos >= (response_len - 3))
2005 /* Test HTTP status code */
2006 if (server_response[pos + 1] != '2')
2015 /*********************************************************************
2017 * Function : seed_rng
2019 * Description : Seeding the RNG for all SSL uses
2022 * 1 : csp = Current client state (buffers, headers, etc...)
2024 * Returns : -1 => RNG wasn't seed successfully
2025 * 0 => RNG is seeded successfully
2027 *********************************************************************/
2028 static int seed_rng(struct client_state *csp)
2031 char err_buf[ERROR_BUF_SIZE];
2033 if (rng_seeded == 0)
2035 privoxy_mutex_lock(&rng_mutex);
2036 if (rng_seeded == 0)
2038 mbedtls_ctr_drbg_init(&ctr_drbg);
2039 mbedtls_entropy_init(&entropy);
2040 ret = mbedtls_ctr_drbg_seed(&ctr_drbg, mbedtls_entropy_func,
2044 mbedtls_strerror(ret, err_buf, sizeof(err_buf));
2045 log_error(LOG_LEVEL_ERROR,
2046 "mbedtls_ctr_drbg_seed failed: %s", err_buf);
2047 privoxy_mutex_unlock(&rng_mutex);
2052 privoxy_mutex_unlock(&rng_mutex);