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 extern 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 memset(err_buf, 0, sizeof(err_buf));
245 mbedtls_strerror(ret, err_buf, sizeof(err_buf));
246 log_error(LOG_LEVEL_ERROR,
247 "Sending data over TLS/SSL failed: %s", err_buf);
251 /* Adding count of sent bytes to position in buffer */
252 pos = pos + send_len;
259 /*********************************************************************
261 * Function : ssl_recv_data
263 * Description : Receives data from given SSL context and puts
267 * 1 : ssl = SSL context to receive data from
268 * 2 : buf = Pointer to buffer where data will be written
269 * 3 : max_length = Maximum number of bytes to read
271 * Returns : Number of bytes read, 0 for EOF, or negative
274 *********************************************************************/
275 extern int ssl_recv_data(mbedtls_ssl_context *ssl, unsigned char *buf, size_t max_length)
278 memset(buf, 0, max_length);
281 * Receiving data from SSL context into buffer
285 ret = mbedtls_ssl_read(ssl, buf, max_length);
286 } while (ret == MBEDTLS_ERR_SSL_WANT_READ
287 || ret == MBEDTLS_ERR_SSL_WANT_WRITE);
291 char err_buf[ERROR_BUF_SIZE];
293 memset(err_buf, 0, sizeof(err_buf));
294 mbedtls_strerror(ret, err_buf, sizeof(err_buf));
295 log_error(LOG_LEVEL_ERROR,
296 "Receiving data over TLS/SSL failed: %s", err_buf);
303 /*********************************************************************
305 * Function : ssl_flush_socket
307 * Description : Send any pending "buffered" content with given
308 * SSL connection. Alternative to function flush_socket.
311 * 1 : ssl = SSL context to send buffer to
312 * 2 : iob = The I/O buffer to flush, usually csp->iob.
314 * Returns : On success, the number of bytes send are returned (zero
315 * indicates nothing was sent). On error, -1 is returned.
317 *********************************************************************/
318 extern long ssl_flush_socket(mbedtls_ssl_context *ssl, struct iob *iob)
320 /* Computing length of buffer part to send */
321 long len = iob->eod - iob->cur;
328 /* Sending data to given SSl context */
329 if (ssl_send_data(ssl, (const unsigned char *)iob->cur, (size_t)len) < 0)
333 iob->eod = iob->cur = iob->buf;
338 /*********************************************************************
340 * Function : ssl_debug_callback
342 * Description : Debug callback function for mbedtls library.
343 * Prints info into log file.
346 * 1 : ctx = File to save log in
347 * 2 : level = Debug level
348 * 3 : file = File calling debug message
349 * 4 : line = Line calling debug message
350 * 5 : str = Debug message
354 *********************************************************************/
355 static void ssl_debug_callback(void *ctx, int level, const char *file, int line, const char *str)
359 fprintf((FILE *)ctx, "%s:%04d: %s", file, line, str);
361 log_error(LOG_LEVEL_INFO, "SSL debug message: %s:%04d: %s", file, line, str);
366 /*********************************************************************
368 * Function : create_client_ssl_connection
370 * Description : Creates TLS/SSL secured connection with client
373 * 1 : csp = Current client state (buffers, headers, etc...)
375 * Returns : 0 on success, negative value if connection wasn't created
378 *********************************************************************/
379 extern int create_client_ssl_connection(struct client_state *csp)
381 /* Paths to certificates file and key file */
382 char *key_file = NULL;
383 char *ca_file = NULL;
384 char *cert_file = NULL;
386 char err_buf[ERROR_BUF_SIZE];
388 memset(err_buf, 0, sizeof(err_buf));
391 * Initializing mbedtls structures for TLS/SSL connection
393 mbedtls_net_init(&(csp->mbedtls_client_attr.socket_fd));
394 mbedtls_ssl_init(&(csp->mbedtls_client_attr.ssl));
395 mbedtls_ssl_config_init(&(csp->mbedtls_client_attr.conf));
396 mbedtls_x509_crt_init(&(csp->mbedtls_client_attr.server_cert));
397 mbedtls_pk_init(&(csp->mbedtls_client_attr.prim_key));
398 #if defined(MBEDTLS_SSL_CACHE_C)
399 mbedtls_ssl_cache_init(&(csp->mbedtls_client_attr.cache));
403 * Preparing hash of host for creating certificates
405 ret = host_to_hash(csp);
408 log_error(LOG_LEVEL_ERROR, "Generating hash of host failed: %d", ret);
414 * Preparing paths to certificates files and key file
416 ca_file = csp->config->ca_cert_file;
417 cert_file = make_certs_path(csp->config->certificate_directory,
418 (const char *)csp->http->hash_of_host_hex, CERT_FILE_TYPE);
419 key_file = make_certs_path(csp->config->certificate_directory,
420 (const char *)csp->http->hash_of_host_hex, KEY_FILE_TYPE);
422 if (cert_file == NULL || key_file == NULL)
429 * Generating certificate for requested host. Mutex to prevent
430 * certificate and key inconsistence must be locked.
432 unsigned int cert_mutex_id = get_certificate_mutex_id(csp);
433 privoxy_mutex_lock(&(certificates_mutexes[cert_mutex_id]));
435 ret = generate_webpage_certificate(csp);
438 log_error(LOG_LEVEL_ERROR,
439 "Generate_webpage_certificate failed: %d", ret);
440 privoxy_mutex_unlock(&(certificates_mutexes[cert_mutex_id]));
444 privoxy_mutex_unlock(&(certificates_mutexes[cert_mutex_id]));
457 * Loading CA file, webpage certificate and key files
459 ret = mbedtls_x509_crt_parse_file(&(csp->mbedtls_client_attr.server_cert),
463 mbedtls_strerror(ret, err_buf, sizeof(err_buf));
464 log_error(LOG_LEVEL_ERROR,
465 "Loading webpage certificate %s failed: %s", cert_file, err_buf);
470 ret = mbedtls_x509_crt_parse_file(&(csp->mbedtls_client_attr.server_cert),
474 mbedtls_strerror(ret, err_buf, sizeof(err_buf));
475 log_error(LOG_LEVEL_ERROR,
476 "Loading CA certificate %s failed: %s", ca_file, err_buf);
481 ret = mbedtls_pk_parse_keyfile(&(csp->mbedtls_client_attr.prim_key),
485 mbedtls_strerror(ret, err_buf, sizeof(err_buf));
486 log_error(LOG_LEVEL_ERROR,
487 "Loading and parsing webpage certificate private key %s failed: %s",
494 * Setting SSL parameters
496 ret = mbedtls_ssl_config_defaults(&(csp->mbedtls_client_attr.conf),
497 MBEDTLS_SSL_IS_SERVER, MBEDTLS_SSL_TRANSPORT_STREAM,
498 MBEDTLS_SSL_PRESET_DEFAULT);
501 mbedtls_strerror(ret, err_buf, sizeof(err_buf));
502 log_error(LOG_LEVEL_ERROR,
503 "mbedtls_ssl_config_defaults failed: %s", err_buf);
508 mbedtls_ssl_conf_rng(&(csp->mbedtls_client_attr.conf),
509 mbedtls_ctr_drbg_random, &ctr_drbg);
510 mbedtls_ssl_conf_dbg(&(csp->mbedtls_client_attr.conf),
511 ssl_debug_callback, stdout);
513 #if defined(MBEDTLS_SSL_CACHE_C)
514 mbedtls_ssl_conf_session_cache(&(csp->mbedtls_client_attr.conf),
515 &(csp->mbedtls_client_attr.cache), mbedtls_ssl_cache_get,
516 mbedtls_ssl_cache_set);
520 * Setting certificates
522 ret = mbedtls_ssl_conf_own_cert(&(csp->mbedtls_client_attr.conf),
523 &(csp->mbedtls_client_attr.server_cert),
524 &(csp->mbedtls_client_attr.prim_key));
527 mbedtls_strerror(ret, err_buf, sizeof(err_buf));
528 log_error(LOG_LEVEL_ERROR,
529 "mbedtls_ssl_conf_own_cert failed: %s", err_buf);
534 ret = mbedtls_ssl_setup(&(csp->mbedtls_client_attr.ssl),
535 &(csp->mbedtls_client_attr.conf));
538 mbedtls_strerror(ret, err_buf, sizeof(err_buf));
539 log_error(LOG_LEVEL_ERROR, "mbedtls_ssl_setup failed: %s", err_buf);
544 mbedtls_ssl_set_bio(&(csp->mbedtls_client_attr.ssl),
545 &(csp->mbedtls_client_attr.socket_fd), mbedtls_net_send,
546 mbedtls_net_recv, NULL);
547 mbedtls_ssl_session_reset(&(csp->mbedtls_client_attr.ssl));
550 * Setting socket fd in mbedtls_net_context structure. This structure
551 * can't be set by mbedtls functions, because we already have created
552 * a TCP connection when this function is called.
554 csp->mbedtls_client_attr.socket_fd.fd = csp->cfd;
557 * Handshake with client
559 log_error(LOG_LEVEL_CONNECT,
560 "Performing the TLS/SSL handshake with client. Hash of host: %s",
561 csp->http->hash_of_host_hex);
562 while ((ret = mbedtls_ssl_handshake(&(csp->mbedtls_client_attr.ssl))) != 0)
564 if (ret != MBEDTLS_ERR_SSL_WANT_READ &&
565 ret != MBEDTLS_ERR_SSL_WANT_WRITE)
567 mbedtls_strerror(ret, err_buf, sizeof(err_buf));
568 log_error(LOG_LEVEL_ERROR,
569 "medtls_ssl_handshake with client failed: %s", err_buf);
575 log_error(LOG_LEVEL_CONNECT, "Client successfully connected over TLS/SSL");
576 csp->ssl_with_client_is_opened = 1;
580 * Freeing allocated paths to files
585 /* Freeing structures if connection wasn't created successfully */
588 free_client_ssl_structures(csp);
594 /*********************************************************************
596 * Function : close_client_ssl_connection
598 * Description : Closes TLS/SSL connection with client. This function
599 * checks if this connection is already created.
602 * 1 : csp = Current client state (buffers, headers, etc...)
606 *********************************************************************/
607 extern void close_client_ssl_connection(struct client_state *csp)
611 if (csp->ssl_with_client_is_opened == 0)
617 * Notifying the peer that the connection is being closed.
620 ret = mbedtls_ssl_close_notify(&(csp->mbedtls_client_attr.ssl));
621 } while (ret == MBEDTLS_ERR_SSL_WANT_WRITE);
623 free_client_ssl_structures(csp);
624 csp->ssl_with_client_is_opened = 0;
628 /*********************************************************************
630 * Function : free_client_ssl_structures
632 * Description : Frees structures used for SSL communication with
636 * 1 : csp = Current client state (buffers, headers, etc...)
640 *********************************************************************/
641 static void free_client_ssl_structures(struct client_state *csp)
644 * We can't use function mbedtls_net_free, because this function
645 * inter alia close TCP connection on setted fd. Instead of this
646 * function, we change fd to -1, which is the same what does
647 * rest of mbedtls_net_free function.
649 csp->mbedtls_client_attr.socket_fd.fd = -1;
651 /* Freeing mbedtls structures */
652 mbedtls_x509_crt_free(&(csp->mbedtls_client_attr.server_cert));
653 mbedtls_pk_free(&(csp->mbedtls_client_attr.prim_key));
654 mbedtls_ssl_free(&(csp->mbedtls_client_attr.ssl));
655 mbedtls_ssl_config_free(&(csp->mbedtls_client_attr.conf));
656 #if defined(MBEDTLS_SSL_CACHE_C)
657 mbedtls_ssl_cache_free(&(csp->mbedtls_client_attr.cache));
662 /*********************************************************************
664 * Function : create_server_ssl_connection
666 * Description : Creates TLS/SSL secured connection with server.
669 * 1 : csp = Current client state (buffers, headers, etc...)
671 * Returns : 0 on success, negative value if connection wasn't created
674 *********************************************************************/
675 extern int create_server_ssl_connection(struct client_state *csp)
678 char err_buf[ERROR_BUF_SIZE];
679 char *trusted_cas_file = NULL;
680 int auth_mode = MBEDTLS_SSL_VERIFY_REQUIRED;
682 memset(err_buf, 0, sizeof(err_buf));
684 csp->server_cert_verification_result = SSL_CERT_NOT_VERIFIED;
685 csp->server_certs_chain.next = NULL;
687 /* Setting path to file with trusted CAs */
688 trusted_cas_file = csp->config->trusted_cas_file;
691 * Initializing mbedtls structures for TLS/SSL connection
693 mbedtls_net_init(&(csp->mbedtls_server_attr.socket_fd));
694 mbedtls_ssl_init(&(csp->mbedtls_server_attr.ssl));
695 mbedtls_ssl_config_init(&(csp->mbedtls_server_attr.conf));
696 mbedtls_x509_crt_init( &(csp->mbedtls_server_attr.ca_cert));
699 * Setting socket fd in mbedtls_net_context structure. This structure
700 * can't be set by mbedtls functions, because we already have created
701 * TCP connection when calling this function.
703 csp->mbedtls_server_attr.socket_fd.fd = csp->server_connection.sfd;
716 * Loading file with trusted CAs
718 ret = mbedtls_x509_crt_parse_file(&(csp->mbedtls_server_attr.ca_cert),
722 mbedtls_strerror(ret, err_buf, sizeof(err_buf));
723 log_error(LOG_LEVEL_ERROR, "Loading trusted CAs file %s failed: %s",
724 trusted_cas_file, err_buf);
730 * Set TLS/SSL options
732 ret = mbedtls_ssl_config_defaults(&(csp->mbedtls_server_attr.conf),
733 MBEDTLS_SSL_IS_CLIENT,
734 MBEDTLS_SSL_TRANSPORT_STREAM,
735 MBEDTLS_SSL_PRESET_DEFAULT);
738 mbedtls_strerror(ret, err_buf, sizeof(err_buf));
739 log_error(LOG_LEVEL_ERROR, "mbedtls_ssl_config_defaults failed: %s",
746 * Setting how strict should certificate verification be and other
747 * parameters for certificate verification
749 if (csp->dont_verify_certificate)
751 auth_mode = MBEDTLS_SSL_VERIFY_NONE;
754 mbedtls_ssl_conf_authmode(&(csp->mbedtls_server_attr.conf), auth_mode);
755 mbedtls_ssl_conf_ca_chain(&(csp->mbedtls_server_attr.conf),
756 &(csp->mbedtls_server_attr.ca_cert), NULL);
758 /* Setting callback function for certificates verification */
759 mbedtls_ssl_conf_verify(&(csp->mbedtls_server_attr.conf),
760 ssl_verify_callback, (void *)csp);
762 mbedtls_ssl_conf_rng(&(csp->mbedtls_server_attr.conf),
763 mbedtls_ctr_drbg_random, &ctr_drbg);
764 mbedtls_ssl_conf_dbg(&(csp->mbedtls_server_attr.conf),
765 ssl_debug_callback, stdout);
767 ret = mbedtls_ssl_setup(&(csp->mbedtls_server_attr.ssl),
768 &(csp->mbedtls_server_attr.conf));
771 mbedtls_strerror(ret, err_buf, sizeof(err_buf));
772 log_error(LOG_LEVEL_ERROR, "mbedtls_ssl_setup failed: %s", err_buf);
778 * Set the hostname to check against the received server certificate
780 ret = mbedtls_ssl_set_hostname(&(csp->mbedtls_server_attr.ssl),
784 mbedtls_strerror(ret, err_buf, sizeof(err_buf));
785 log_error(LOG_LEVEL_ERROR, "mbedtls_ssl_set_hostname failed: %s",
791 mbedtls_ssl_set_bio(&(csp->mbedtls_server_attr.ssl),
792 &(csp->mbedtls_server_attr.socket_fd), mbedtls_net_send,
793 mbedtls_net_recv, NULL);
796 * Handshake with server
798 log_error(LOG_LEVEL_CONNECT,
799 "Performing the TLS/SSL handshake with server");
801 while ((ret = mbedtls_ssl_handshake(&(csp->mbedtls_server_attr.ssl))) != 0)
803 if (ret != MBEDTLS_ERR_SSL_WANT_READ
804 && ret != MBEDTLS_ERR_SSL_WANT_WRITE)
806 mbedtls_strerror(ret, err_buf, sizeof(err_buf));
808 if (ret == MBEDTLS_ERR_X509_CERT_VERIFY_FAILED)
810 log_error(LOG_LEVEL_ERROR,
811 "Server certificate verification failed: %s", err_buf);
812 csp->server_cert_verification_result =
813 mbedtls_ssl_get_verify_result(&(csp->mbedtls_server_attr.ssl));
819 log_error(LOG_LEVEL_ERROR,
820 "mbedtls_ssl_handshake with server failed: %s", err_buf);
827 log_error(LOG_LEVEL_CONNECT, "Server successfully connected over TLS/SSL");
830 * Server certificate chain is valid, so we can clean
831 * chain, because we will not send it to client.
833 free_certificate_chain(csp);
835 csp->ssl_with_server_is_opened = 1;
836 csp->server_cert_verification_result =
837 mbedtls_ssl_get_verify_result(&(csp->mbedtls_server_attr.ssl));
840 /* Freeing structures if connection wasn't created successfully */
843 free_server_ssl_structures(csp);
850 /*********************************************************************
852 * Function : close_server_ssl_connection
854 * Description : Closes TLS/SSL connection with server. This function
855 * checks if this connection is already opened.
858 * 1 : csp = Current client state (buffers, headers, etc...)
862 *********************************************************************/
863 static void close_server_ssl_connection(struct client_state *csp)
867 if (csp->ssl_with_server_is_opened == 0)
873 * Notifying the peer that the connection is being closed.
876 ret = mbedtls_ssl_close_notify(&(csp->mbedtls_server_attr.ssl));
877 } while (ret == MBEDTLS_ERR_SSL_WANT_WRITE);
879 free_server_ssl_structures(csp);
880 csp->ssl_with_server_is_opened = 0;
884 /*********************************************************************
886 * Function : free_server_ssl_structures
888 * Description : Frees structures used for SSL communication with server
891 * 1 : csp = Current client state (buffers, headers, etc...)
895 *********************************************************************/
896 static void free_server_ssl_structures(struct client_state *csp)
899 * We can't use function mbedtls_net_free, because this function
900 * inter alia close TCP connection on setted fd. Instead of this
901 * function, we change fd to -1, which is the same what does
902 * rest of mbedtls_net_free function.
904 csp->mbedtls_client_attr.socket_fd.fd = -1;
906 mbedtls_x509_crt_free(&(csp->mbedtls_server_attr.ca_cert));
907 mbedtls_ssl_free(&(csp->mbedtls_server_attr.ssl));
908 mbedtls_ssl_config_free(&(csp->mbedtls_server_attr.conf));
912 /*********************************************************************
914 * Function : close_client_and_server_ssl_connections
916 * Description : Checks if client or server should use secured
917 * connection over SSL and if so, closes all of them.
920 * 1 : csp = Current client state (buffers, headers, etc...)
924 *********************************************************************/
925 extern void close_client_and_server_ssl_connections(struct client_state *csp)
927 if (client_use_ssl(csp) == 1)
929 close_client_ssl_connection(csp);
931 if (server_use_ssl(csp) == 1)
933 close_server_ssl_connection(csp);
937 /*====================== Certificates ======================*/
939 /*********************************************************************
941 * Function : write_certificate
943 * Description : Writes certificate into file.
946 * 1 : crt = certificate to write into file
947 * 2 : output_file = path to save certificate file
948 * 3 : f_rng = mbedtls_ctr_drbg_random
949 * 4 : p_rng = mbedtls_ctr_drbg_context
951 * Returns : Length of written certificate on success or negative value
954 *********************************************************************/
955 static int write_certificate(mbedtls_x509write_cert *crt, const char *output_file,
956 int(*f_rng)(void *, unsigned char *, size_t), void *p_rng)
960 unsigned char cert_buf[CERTIFICATE_BUF_SIZE + 1]; /* Buffer for certificate in PEM format + terminating NULL */
962 char err_buf[ERROR_BUF_SIZE];
964 memset(err_buf, 0, sizeof(err_buf));
965 memset(cert_buf, 0, sizeof(cert_buf));
968 * Writing certificate into PEM string. If buffer is too small, function
969 * returns specific error and no buffer overflow can happen.
971 if ((ret = mbedtls_x509write_crt_pem(crt, cert_buf,
972 sizeof(cert_buf) - 1, f_rng, p_rng)) != 0)
974 mbedtls_strerror(ret, err_buf, sizeof(err_buf));
975 log_error(LOG_LEVEL_ERROR,
976 "Writing certificate into buffer failed: %s", err_buf);
980 len = strlen((char *)cert_buf);
983 * Saving certificate into file
985 if ((f = fopen(output_file, "w")) == NULL)
987 log_error(LOG_LEVEL_ERROR, "Opening file %s to save certificate failed",
992 if (fwrite(cert_buf, 1, len, f) != len)
994 log_error(LOG_LEVEL_ERROR,
995 "Writing certificate into file %s failed", output_file);
1006 /*********************************************************************
1008 * Function : write_private_key
1010 * Description : Writes private key into file and copies saved
1011 * content into given pointer to string. If function
1012 * returns 0 for success, this copy must be freed by
1016 * 1 : key = key to write into file
1017 * 2 : ret_buf = pointer to string with created key file content
1018 * 3 : key_file_path = path where to save key file
1020 * Returns : Length of written private key on success or negative value
1023 *********************************************************************/
1024 static int write_private_key(mbedtls_pk_context *key, unsigned char **ret_buf,
1025 const char *key_file_path)
1027 size_t len = 0; /* Length of created key */
1028 FILE *f = NULL; /* File to save certificate */
1030 char err_buf[ERROR_BUF_SIZE];
1032 memset(err_buf, 0, sizeof(err_buf));
1034 /* Initializing buffer for key file content */
1035 *ret_buf = (unsigned char *)malloc(PRIVATE_KEY_BUF_SIZE + 1);
1036 if (*ret_buf == NULL)
1038 log_error(LOG_LEVEL_ERROR,
1039 "Creating buffer for private key failed: malloc fail");
1043 memset(*ret_buf, 0, PRIVATE_KEY_BUF_SIZE + 1);
1046 * Writing private key into PEM string
1048 if ((ret = mbedtls_pk_write_key_pem(key, *ret_buf, PRIVATE_KEY_BUF_SIZE)) != 0)
1050 mbedtls_strerror(ret, err_buf, sizeof(err_buf));
1051 log_error(LOG_LEVEL_ERROR,
1052 "Writing private key into PEM string failed: %s", err_buf);
1056 len = strlen((char *)*ret_buf);
1059 * Saving key into file
1061 if ((f = fopen(key_file_path, "wb")) == NULL)
1063 log_error(LOG_LEVEL_ERROR,
1064 "Opening file %s to save private key failed: %E",
1070 if (fwrite(*ret_buf, 1, len, f) != len)
1073 log_error(LOG_LEVEL_ERROR,
1074 "Writing private key into file %s failed",
1093 /*********************************************************************
1095 * Function : generate_key
1097 * Description : Tests if private key for host saved in csp already
1098 * exists. If this file doesn't exists, a new key is
1099 * generated and saved in a file. The generated key is also
1100 * copied into given parameter key_buf, which must be then
1101 * freed by caller. If file with key exists, key_buf
1102 * contain NULL and no private key is generated.
1105 * 1 : key_buf = buffer to save new generated key
1106 * 2 : csp = Current client state (buffers, headers, etc...)
1108 * Returns : -1 => Error while generating private key
1109 * 0 => Key already exists
1110 * >0 => Length of generated private key
1112 *********************************************************************/
1113 static int generate_key(unsigned char **key_buf, struct client_state *csp)
1115 mbedtls_pk_context key;
1116 key_options key_opt;
1118 char err_buf[ERROR_BUF_SIZE];
1120 key_opt.key_file_path = NULL;
1121 memset(err_buf, 0, sizeof(err_buf));
1124 * Initializing structures for key generating
1126 mbedtls_pk_init(&key);
1129 * Preparing path for key file and other properties for generating key
1131 key_opt.type = MBEDTLS_PK_RSA;
1132 key_opt.rsa_keysize = RSA_KEYSIZE;
1134 key_opt.key_file_path = make_certs_path(csp->config->certificate_directory,
1135 (char *)csp->http->hash_of_host_hex, KEY_FILE_TYPE);
1136 if (key_opt.key_file_path == NULL)
1143 * Test if key already exists. If so, we don't have to create it again.
1145 if (file_exists(key_opt.key_file_path) == 1)
1154 ret = seed_rng(csp);
1162 * Setting attributes of private key and generating it
1164 if ((ret = mbedtls_pk_setup(&key,
1165 mbedtls_pk_info_from_type(key_opt.type))) != 0)
1167 mbedtls_strerror(ret, err_buf, sizeof(err_buf));
1168 log_error(LOG_LEVEL_ERROR, "mbedtls_pk_setup failed: %s", err_buf);
1173 ret = mbedtls_rsa_gen_key(mbedtls_pk_rsa(key), mbedtls_ctr_drbg_random,
1174 &ctr_drbg, (unsigned)key_opt.rsa_keysize, RSA_KEY_PUBLIC_EXPONENT);
1177 mbedtls_strerror(ret, err_buf, sizeof(err_buf));
1178 log_error(LOG_LEVEL_ERROR, "Key generating failed: %s", err_buf);
1184 * Exporting private key into file
1186 if ((ret = write_private_key(&key, key_buf, key_opt.key_file_path)) < 0)
1188 log_error(LOG_LEVEL_ERROR,
1189 "Writing private key into file %s failed", key_opt.key_file_path);
1196 * Freeing used variables
1198 freez(key_opt.key_file_path);
1200 mbedtls_pk_free(&key);
1206 /*********************************************************************
1208 * Function : generate_webpage_certificate
1210 * Description : Creates certificate file in presetted directory.
1211 * If certificate already exists, no other certificate
1212 * will be created. Subject of certificate is named
1213 * by csp->http->host from parameter. This function also
1214 * triggers generating of private key for new certificate.
1217 * 1 : csp = Current client state (buffers, headers, etc...)
1219 * Returns : -1 => Error while creating certificate.
1220 * 0 => Certificate alreaday exist.
1221 * >0 => Length of created certificate.
1223 *********************************************************************/
1224 extern int generate_webpage_certificate(struct client_state * csp)
1226 mbedtls_x509_crt issuer_cert;
1227 mbedtls_pk_context loaded_issuer_key, loaded_subject_key;
1228 mbedtls_pk_context *issuer_key = &loaded_issuer_key;
1229 mbedtls_pk_context *subject_key = &loaded_subject_key;
1230 mbedtls_x509write_cert cert;
1233 unsigned char *key_buf = NULL; /* Buffer for created key */
1236 char err_buf[ERROR_BUF_SIZE];
1237 cert_options cert_opt;
1239 memset(err_buf, 0, sizeof(err_buf));
1241 /* Paths to keys and certificates needed to create certificate */
1242 cert_opt.issuer_key = NULL;
1243 cert_opt.subject_key = NULL;
1244 cert_opt.issuer_crt = NULL;
1245 cert_opt.output_file = NULL;
1248 * Create key for requested host
1250 int subject_key_len = generate_key(&key_buf, csp);
1251 if (subject_key_len < 0)
1253 log_error(LOG_LEVEL_ERROR, "Key generating failed");
1258 * Initializing structures for certificate generating
1260 mbedtls_x509write_crt_init(&cert);
1261 mbedtls_x509write_crt_set_md_alg( &cert, CERT_SIGNATURE_ALGORITHM);
1262 mbedtls_pk_init(&loaded_issuer_key);
1263 mbedtls_pk_init(&loaded_subject_key);
1264 mbedtls_mpi_init(&serial);
1265 mbedtls_x509_crt_init(&issuer_cert);
1268 * Presetting parameters for certificate. We must compute total length
1271 size_t cert_params_len = strlen(CERT_PARAM_COMMON_NAME) +
1272 strlen(CERT_PARAM_ORGANIZATION) + strlen(CERT_PARAM_COUNTRY) +
1273 strlen(CERT_PARAM_ORG_UNIT) +
1274 3 * strlen(csp->http->host) + 1;
1275 char cert_params[cert_params_len];
1276 memset(cert_params, 0, cert_params_len);
1279 * Converting unsigned long serial number to char * serial number.
1280 * We must compute length of serial number in string + terminating null.
1282 unsigned long certificate_serial = get_certificate_serial(csp);
1283 int serial_num_size = snprintf(NULL, 0, "%lu", certificate_serial) + 1;
1284 if (serial_num_size <= 0)
1286 serial_num_size = 1;
1289 char serial_num_text[serial_num_size]; /* Buffer for serial number */
1290 ret = snprintf(serial_num_text, (size_t)serial_num_size, "%lu", certificate_serial);
1291 if (ret < 0 || ret >= serial_num_size)
1293 log_error(LOG_LEVEL_ERROR,
1294 "Converting certificate serial number into string failed");
1300 * Preparing parameters for certificate
1302 strlcpy(cert_params, CERT_PARAM_COMMON_NAME, cert_params_len);
1303 strlcat(cert_params, csp->http->host, cert_params_len);
1304 strlcat(cert_params, CERT_PARAM_ORGANIZATION, cert_params_len);
1305 strlcat(cert_params, csp->http->host, cert_params_len);
1306 strlcat(cert_params, CERT_PARAM_ORG_UNIT, cert_params_len);
1307 strlcat(cert_params, csp->http->host, cert_params_len);
1308 strlcat(cert_params, CERT_PARAM_COUNTRY, cert_params_len);
1310 cert_opt.issuer_crt = csp->config->ca_cert_file;
1311 cert_opt.issuer_key = csp->config->ca_key_file;
1312 cert_opt.subject_key = make_certs_path(csp->config->certificate_directory,
1313 (const char *)csp->http->hash_of_host_hex, KEY_FILE_TYPE);
1314 cert_opt.output_file = make_certs_path(csp->config->certificate_directory,
1315 (const char *)csp->http->hash_of_host_hex, CERT_FILE_TYPE);
1317 if (cert_opt.subject_key == NULL || cert_opt.output_file == NULL)
1323 cert_opt.subject_pwd = CERT_SUBJECT_PASSWORD;
1324 cert_opt.issuer_pwd = csp->config->ca_password;
1325 cert_opt.subject_name = cert_params;
1326 cert_opt.not_before = GENERATED_CERT_VALID_FROM;
1327 cert_opt.not_after = GENERATED_CERT_VALID_TO;
1328 cert_opt.serial = serial_num_text;
1330 cert_opt.max_pathlen = -1;
1333 * Test if certificate exists and private key was already created
1335 if (file_exists(cert_opt.output_file) == 1 && subject_key_len == 0)
1344 ret = seed_rng(csp);
1352 * Parse serial to MPI
1354 ret = mbedtls_mpi_read_string(&serial, 10, cert_opt.serial);
1357 mbedtls_strerror(ret, err_buf, sizeof(err_buf));
1358 log_error(LOG_LEVEL_ERROR,
1359 "mbedtls_mpi_read_string failed: %s", err_buf);
1365 * Loading certificates
1367 ret = mbedtls_x509_crt_parse_file(&issuer_cert, cert_opt.issuer_crt);
1370 mbedtls_strerror(ret, err_buf, sizeof(err_buf));
1371 log_error(LOG_LEVEL_ERROR, "Loading issuer certificate %s failed: %s",
1372 cert_opt.issuer_crt, err_buf);
1377 ret = mbedtls_x509_dn_gets(cert_opt.issuer_name,
1378 sizeof(cert_opt.issuer_name), &issuer_cert.subject);
1381 mbedtls_strerror(ret, err_buf, sizeof(err_buf));
1382 log_error(LOG_LEVEL_ERROR, "mbedtls_x509_dn_gets failed: %s", err_buf);
1388 * Loading keys from file or from buffer
1390 if (key_buf != NULL && subject_key_len > 0)
1392 /* Key was created in this function and is stored in buffer */
1393 ret = mbedtls_pk_parse_key(&loaded_subject_key, key_buf,
1394 (size_t)(subject_key_len + 1), (unsigned const char *)
1395 cert_opt.subject_pwd, strlen(cert_opt.subject_pwd));
1399 /* Key wasn't created in this function, because it already existed */
1400 ret = mbedtls_pk_parse_keyfile(&loaded_subject_key,
1401 cert_opt.subject_key, cert_opt.subject_pwd);
1406 mbedtls_strerror(ret, err_buf, sizeof(err_buf));
1407 log_error(LOG_LEVEL_ERROR, "Parsing subject key %s failed: %s",
1408 cert_opt.subject_key, err_buf);
1413 ret = mbedtls_pk_parse_keyfile(&loaded_issuer_key, cert_opt.issuer_key,
1414 cert_opt.issuer_pwd);
1417 mbedtls_strerror(ret, err_buf, sizeof(err_buf));
1418 log_error(LOG_LEVEL_ERROR,
1419 "Parsing issuer key %s failed: %s", cert_opt.issuer_key, err_buf);
1425 * Check if key and issuer certificate match
1427 if (!mbedtls_pk_can_do(&issuer_cert.pk, MBEDTLS_PK_RSA) ||
1428 mbedtls_mpi_cmp_mpi(&mbedtls_pk_rsa(issuer_cert.pk)->N,
1429 &mbedtls_pk_rsa(*issuer_key)->N) != 0 ||
1430 mbedtls_mpi_cmp_mpi( &mbedtls_pk_rsa(issuer_cert.pk)->E,
1431 &mbedtls_pk_rsa(*issuer_key )->E) != 0)
1433 log_error(LOG_LEVEL_ERROR,
1434 "Issuer key doesn't match issuer certificate");
1439 mbedtls_x509write_crt_set_subject_key(&cert, subject_key);
1440 mbedtls_x509write_crt_set_issuer_key(&cert, issuer_key);
1443 * Setting parameters of signed certificate
1445 ret = mbedtls_x509write_crt_set_subject_name(&cert, cert_opt.subject_name);
1448 mbedtls_strerror(ret, err_buf, sizeof(err_buf));
1449 log_error(LOG_LEVEL_ERROR,
1450 "Setting subject name in signed certificate failed: %s", err_buf);
1455 ret = mbedtls_x509write_crt_set_issuer_name(&cert, cert_opt.issuer_name);
1458 mbedtls_strerror(ret, err_buf, sizeof(err_buf));
1459 log_error(LOG_LEVEL_ERROR,
1460 "Setting issuer name in signed certificate failed: %s", err_buf);
1465 ret = mbedtls_x509write_crt_set_serial(&cert, &serial);
1468 mbedtls_strerror(ret, err_buf, sizeof(err_buf));
1469 log_error(LOG_LEVEL_ERROR,
1470 "Setting serial number in signed certificate failed: %s", err_buf);
1475 ret = mbedtls_x509write_crt_set_validity(&cert, cert_opt.not_before,
1476 cert_opt.not_after);
1479 mbedtls_strerror(ret, err_buf, sizeof(err_buf));
1480 log_error(LOG_LEVEL_ERROR,
1481 "Setting validity in signed certificate failed: %s", err_buf);
1487 * Setting the basicConstraints extension for certificate
1489 ret = mbedtls_x509write_crt_set_basic_constraints(&cert, cert_opt.is_ca,
1490 cert_opt.max_pathlen);
1493 mbedtls_strerror(ret, err_buf, sizeof(err_buf));
1494 log_error(LOG_LEVEL_ERROR, "Setting the basicConstraints extension "
1495 "in signed certificate failed: %s", err_buf);
1500 #if defined(MBEDTLS_SHA1_C)
1501 /* Setting the subjectKeyIdentifier extension for certificate */
1502 ret = mbedtls_x509write_crt_set_subject_key_identifier(&cert);
1505 mbedtls_strerror(ret, err_buf, sizeof(err_buf));
1506 log_error(LOG_LEVEL_ERROR, "mbedtls_x509write_crt_set_subject_key_"
1507 "identifier failed: %s", err_buf);
1512 /* Setting the authorityKeyIdentifier extension for certificate */
1513 ret = mbedtls_x509write_crt_set_authority_key_identifier(&cert);
1516 mbedtls_strerror(ret, err_buf, sizeof(err_buf));
1517 log_error(LOG_LEVEL_ERROR, "mbedtls_x509write_crt_set_authority_key_"
1518 "identifier failed: %s", err_buf);
1522 #endif /* MBEDTLS_SHA1_C */
1525 * Writing certificate into file
1527 ret = write_certificate(&cert, cert_opt.output_file,
1528 mbedtls_ctr_drbg_random, &ctr_drbg);
1531 log_error(LOG_LEVEL_ERROR, "Writing certificate into file failed");
1537 * Freeing used structures
1539 mbedtls_x509write_crt_free(&cert);
1540 mbedtls_pk_free(&loaded_subject_key);
1541 mbedtls_pk_free(&loaded_issuer_key);
1542 mbedtls_mpi_free(&serial);
1543 mbedtls_x509_crt_free(&issuer_cert);
1545 freez(cert_opt.subject_key);
1546 freez(cert_opt.output_file);
1553 /*********************************************************************
1555 * Function : make_certs_path
1557 * Description : Creates path to file from three pieces. This fuction
1558 * takes parameters and puts them in one new mallocated
1559 * char * in correct order. Returned variable must be freed
1560 * by caller. This function is mainly used for creating
1561 * paths of certificates and keys files.
1564 * 1 : conf_dir = Name/path of directory where is the file.
1565 * '.' can be used for current directory.
1566 * 2 : file_name = Name of file in conf_dir without suffix.
1567 * 3 : suffix = Suffix of given file_name.
1569 * Returns : path => Path was built up successfully
1570 * NULL => Path can't be built up
1572 *********************************************************************/
1573 static char *make_certs_path(const char *conf_dir, const char *file_name,
1576 /* Test if all given parameters are valid */
1577 if (conf_dir == NULL || *conf_dir == '\0' || file_name == NULL ||
1578 *file_name == '\0' || suffix == NULL || *suffix == '\0')
1580 log_error(LOG_LEVEL_ERROR,
1581 "make_certs_path failed: bad input parameters");
1586 size_t path_size = strlen(conf_dir)
1587 + strlen(file_name) + strlen(suffix) + 2;
1589 /* Setting delimiter and editing path length */
1590 #if defined(_WIN32) || defined(__OS2__)
1591 char delim[] = "\\";
1593 #else /* ifndef _WIN32 || __OS2__ */
1595 #endif /* ifndef _WIN32 || __OS2__ */
1598 * Building up path from many parts
1601 if (*conf_dir != '/' && basedir && *basedir)
1604 * Replacing conf_dir with basedir. This new variable contains
1605 * absolute path to cwd.
1607 path_size += strlen(basedir) + 2;
1608 path = (char *)malloc(path_size);
1611 log_error(LOG_LEVEL_ERROR, "make_certs_path failed: malloc fail");
1614 memset(path, 0, path_size);
1616 strlcpy(path, basedir, path_size);
1617 strlcat(path, delim, path_size);
1618 strlcat(path, conf_dir, path_size);
1619 strlcat(path, delim, path_size);
1620 strlcat(path, file_name, path_size);
1621 strlcat(path, suffix, path_size);
1624 #endif /* defined unix */
1626 path = (char *)malloc(path_size);
1629 log_error(LOG_LEVEL_ERROR, "make_certs_path failed: malloc fail");
1632 memset(path, 0, path_size);
1634 strlcpy(path, conf_dir, path_size);
1635 strlcat(path, delim, path_size);
1636 strlcat(path, file_name, path_size);
1637 strlcat(path, suffix, path_size);
1644 /*********************************************************************
1646 * Function : get_certificate_mutex_id
1648 * Description : Computes mutex id from host name hash. This hash must
1649 * be already saved in csp structure
1652 * 1 : csp = Current client state (buffers, headers, etc...)
1654 * Returns : Mutex id for given host name
1656 *********************************************************************/
1657 static unsigned int get_certificate_mutex_id(struct client_state *csp) {
1658 #ifdef LIMIT_MUTEX_NUMBER
1659 return (unsigned int)(csp->http->hash_of_host[0] % 32);
1661 return (unsigned int)(csp->http->hash_of_host[1]
1662 + 256 * (int)csp->http->hash_of_host[0]);
1663 #endif /* LIMIT_MUTEX_NUMBER */
1667 /*********************************************************************
1669 * Function : get_certificate_serial
1671 * Description : Computes serial number for new certificate from host
1672 * name hash. This hash must be already saved in csp
1676 * 1 : csp = Current client state (buffers, headers, etc...)
1678 * Returns : Serial number for new certificate
1680 *********************************************************************/
1681 static unsigned long get_certificate_serial(struct client_state *csp) {
1682 unsigned long exp = 1;
1683 unsigned long serial = 0;
1685 int i = CERT_SERIAL_NUM_LENGTH;
1686 /* Length of hash is 16 bytes, we must avoid to read next chars */
1698 serial += exp * (unsigned)csp->http->hash_of_host[i];
1705 /*********************************************************************
1707 * Function : ssl_send_certificate_error
1709 * Description : Sends info about invalid server certificate to client.
1710 * Sent message is including all trusted chain certificates,
1711 * that can be downloaded in web browser.
1714 * 1 : csp = Current client state (buffers, headers, etc...)
1718 *********************************************************************/
1719 extern void ssl_send_certificate_error(struct client_state *csp)
1721 size_t message_len = 0;
1723 struct certs_chain *cert = NULL;
1725 /* Header of message with certificate informations */
1726 const char message_begin[] =
1727 "HTTP/1.1 200 OK\r\n"
1728 "Content-Type: text/html\r\n"
1729 "Connection: close\r\n\r\n"
1730 "<html><body><h1>Invalid server certificate</h1><p>Reason: ";
1731 const char message_end[] = "</body></html>\r\n\r\n";
1732 char reason[INVALID_CERT_INFO_BUF_SIZE];
1733 memset(reason, 0, sizeof(reason));
1735 /* Get verification message from verification return code */
1736 mbedtls_x509_crt_verify_info(reason, sizeof(reason), " ",
1737 csp->server_cert_verification_result);
1740 * Computing total length of message with all certificates inside
1742 message_len = strlen(message_begin) + strlen(message_end)
1743 + strlen(reason) + strlen("</p>") + 1;
1745 cert = &(csp->server_certs_chain);
1746 while (cert->next != NULL)
1748 size_t base64_len = 4 * ((strlen(cert->file_buf) + 2) / 3) + 1;
1750 message_len += strlen(cert->text_buf) + strlen("<pre></pre>\n")
1751 + base64_len + strlen("<a href=\"data:application"
1752 "/x-x509-ca-cert;base64,\">Download certificate</a>");
1757 * Joining all blocks in one long message
1759 char message[message_len];
1760 memset(message, 0, message_len);
1762 strlcpy(message, message_begin, message_len);
1763 strlcat(message, reason , message_len);
1764 strlcat(message, "</p>" , message_len);
1766 cert = &(csp->server_certs_chain);
1767 while (cert->next != NULL)
1770 size_t base64_len = 4 * ((strlen(cert->file_buf) + 2) / 3) + 1; /* +1 for terminating null*/
1771 char base64_buf[base64_len];
1772 memset(base64_buf, 0, base64_len);
1774 /* Encoding certificate into base64 code */
1775 ret = mbedtls_base64_encode((unsigned char*)base64_buf,
1776 base64_len, &olen, (const unsigned char*)cert->file_buf,
1777 strlen(cert->file_buf));
1780 log_error(LOG_LEVEL_ERROR,
1781 "Encoding to base64 failed, buffer is to small");
1784 strlcat(message, "<pre>", message_len);
1785 strlcat(message, cert->text_buf, message_len);
1786 strlcat(message, "</pre>\n", message_len);
1790 strlcat(message, "<a href=\"data:application/x-x509-ca-cert;base64,",
1792 strlcat(message, base64_buf, message_len);
1793 strlcat(message, "\">Download certificate</a>", message_len);
1798 strlcat(message, message_end, message_len);
1801 * Sending final message to client
1803 ssl_send_data(&(csp->mbedtls_client_attr.ssl),
1804 (const unsigned char *)message, strlen(message));
1806 * Waiting before closing connection. Some browsers don't show received
1807 * message if there isn't this delay.
1811 free_certificate_chain(csp);
1815 /*********************************************************************
1817 * Function : ssl_verify_callback
1819 * Description : This is a callback function for certificate verification.
1820 * It's called for all certificates in server certificate
1821 * trusted chain and it's preparing information about this
1822 * certificates. Prepared informations can be used to inform
1823 * user about invalid certificates.
1826 * 1 : csp_void = Current client state (buffers, headers, etc...)
1827 * 2 : crt = certificate from trusted chain
1828 * 3 : depth = depth in trusted chain
1829 * 4 : flags = certificate flags
1831 * Returns : 0 on success and negative value on error
1833 *********************************************************************/
1834 static int ssl_verify_callback(void *csp_void, mbedtls_x509_crt *crt,
1835 int depth, uint32_t *flags)
1837 struct client_state *csp = (struct client_state *)csp_void;
1838 struct certs_chain *last = &(csp->server_certs_chain);
1843 * Searching for last item in certificates linked list
1845 while (last->next != NULL)
1851 * Preparing next item in linked list for next certificate
1852 * If malloc fails, we are continuing without this certificate
1854 last->next = (struct certs_chain *)malloc(sizeof(struct certs_chain));
1855 if (last->next != NULL)
1857 last->next->next = NULL;
1858 memset(last->next->text_buf, 0, sizeof(last->next->text_buf));
1859 memset(last->next->file_buf, 0, sizeof(last->next->file_buf));
1862 * Saving certificate file into buffer
1864 if ((ret = mbedtls_pem_write_buffer(PEM_BEGIN_CRT, PEM_END_CRT,
1865 crt->raw.p, crt->raw.len, (unsigned char *)last->file_buf,
1866 sizeof(last->file_buf)-1, &olen)) != 0)
1872 * Saving certificate information into buffer
1874 mbedtls_x509_crt_info(last->text_buf, sizeof(last->text_buf) - 1,
1875 CERT_INFO_PREFIX, crt);
1879 log_error(LOG_LEVEL_ERROR,
1880 "Malloc memory for server certificate informations failed");
1888 /*********************************************************************
1890 * Function : free_certificate_chain
1892 * Description : Frees certificates linked list. This linked list is
1893 * used to save informations about certificates in
1897 * 1 : csp = Current client state (buffers, headers, etc...)
1901 *********************************************************************/
1902 static void free_certificate_chain(struct client_state *csp)
1904 struct certs_chain *cert = csp->server_certs_chain.next;
1906 /* Cleaning buffers */
1907 memset(csp->server_certs_chain.text_buf, 0,
1908 sizeof(csp->server_certs_chain.text_buf));
1909 memset(csp->server_certs_chain.text_buf, 0,
1910 sizeof(csp->server_certs_chain.file_buf));
1911 csp->server_certs_chain.next = NULL;
1913 /* Freeing memory in whole linked list */
1918 struct certs_chain *cert_for_free = cert;
1920 freez(cert_for_free);
1921 } while (cert != NULL);
1926 /*********************************************************************
1928 * Function : file_exists
1930 * Description : Tests if file exists and is readable.
1933 * 1 : path = Path to tested file.
1935 * Returns : 1 => File exists and is readable.
1936 * 0 => File doesn't exist or is not readable.
1938 *********************************************************************/
1939 static int file_exists(const char *path)
1942 if ((f = fopen(path, "r")) != NULL)
1952 /*********************************************************************
1954 * Function : host_to_hash
1956 * Description : Creates MD5 hash from host name. Host name is loaded
1957 * from structure csp and saved again into it.
1960 * 1 : csp = Current client state (buffers, headers, etc...)
1962 * Returns : 1 => Error while creating hash
1963 * 0 => Hash created successfully
1965 *********************************************************************/
1966 static int host_to_hash(struct client_state * csp)
1970 #if !defined(MBEDTLS_MD5_C)
1971 log_error(LOG_LEVEL_ERROR, "MBEDTLS_MD5_C is not defined. Can't create"
1972 "MD5 hash for certificate and key name.");
1975 memset(csp->http->hash_of_host, 0, sizeof(csp->http->hash_of_host));
1976 mbedtls_md5((unsigned char *)csp->http->host, strlen(csp->http->host),
1977 csp->http->hash_of_host);
1979 /* Converting hash into string with hex */
1983 if ((ret = sprintf((char *)csp->http->hash_of_host_hex + 2 * i, "%02x",
1984 csp->http->hash_of_host[i])) < 0)
1986 log_error(LOG_LEVEL_ERROR, "Sprintf return value: %d", ret);
1992 #endif /* MBEDTLS_MD5_C */
1996 /*********************************************************************
1998 * Function : tunnel_established_successfully
2000 * Description : Check if parent proxy server response contains
2001 * informations about successfully created connection with
2002 * destination server. (HTTP/... 2xx ...)
2005 * 1 : server_response = Buffer with parent proxy server response
2006 * 2 : response_len = Length of server_response
2008 * Returns : 1 => Connection created successfully
2009 * 0 => Connection wasn't created successfully
2011 *********************************************************************/
2012 extern int tunnel_established_successfully(const char *server_response,
2013 unsigned int response_len)
2015 unsigned int pos = 0;
2017 if (server_response == NULL)
2022 /* Tests if "HTTP/" string is at the begin of received response */
2023 if (strncmp(server_response, "HTTP/", 5) != 0)
2028 for (pos = 0; pos < response_len; pos++)
2030 if (server_response[pos] == ' ')
2037 * response_len -3 because of buffer end, response structure and 200 code.
2038 * There must be at least 3 chars after space.
2039 * End of buffer: ... 2xx'\0'
2042 if (pos >= (response_len - 3))
2047 /* Test HTTP status code */
2048 if (server_response[pos + 1] != '2')
2057 /*********************************************************************
2059 * Function : seed_rng
2061 * Description : Seeding the RNG for all SSL uses
2064 * 1 : csp = Current client state (buffers, headers, etc...)
2066 * Returns : -1 => RNG wasn't seed successfully
2067 * 0 => RNG is seeded successfully
2069 *********************************************************************/
2070 static int seed_rng(struct client_state *csp)
2073 char err_buf[ERROR_BUF_SIZE];
2075 memset(err_buf, 0, sizeof(err_buf));
2077 if (rng_seeded == 0)
2079 privoxy_mutex_lock(&rng_mutex);
2080 if (rng_seeded == 0)
2082 mbedtls_ctr_drbg_init(&ctr_drbg);
2083 mbedtls_entropy_init(&entropy);
2084 ret = mbedtls_ctr_drbg_seed(&ctr_drbg, mbedtls_entropy_func,
2088 mbedtls_strerror(ret, err_buf, sizeof(err_buf));
2089 log_error(LOG_LEVEL_ERROR,
2090 "mbedtls_ctr_drbg_seed failed: %s", err_buf);
2091 privoxy_mutex_unlock(&rng_mutex);
2096 privoxy_mutex_unlock(&rng_mutex);