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 setted 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 LIMIT_MUTEX_NUMBER /* If this macro is defined, mutexes count for generating private keys is changed from 65536 to 32 */
73 #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 */
74 #define CERT_PARAM_COMMON_NAME "CN="
75 #define CERT_PARAM_ORGANIZATION ",O="
76 #define CERT_PARAM_ORG_UNIT ",OU="
77 #define CERT_PARAM_COUNTRY ",C=CZ"
78 #define KEY_FILE_TYPE ".pem"
79 #define CERT_FILE_TYPE ".crt"
80 #define CERT_SUBJECT_PASSWORD ""
81 #define CERT_INFO_PREFIX ""
84 * Properties of cert for generating
87 char *issuer_crt; /* filename of the issuer certificate */
88 char *subject_key; /* filename of the subject key file */
89 char *issuer_key; /* filename of the issuer key file */
90 const char *subject_pwd; /* password for the subject key file */
91 const char *issuer_pwd; /* password for the issuer key file */
92 char *output_file; /* where to store the constructed key file */
93 const char *subject_name; /* subject name for certificate */
94 char issuer_name[ISSUER_NAME_BUF_SIZE]; /* issuer name for certificate */
95 const char *not_before; /* validity period not before */
96 const char *not_after; /* validity period not after */
97 const char *serial; /* serial number string */
98 int is_ca; /* is a CA certificate */
99 int max_pathlen; /* maximum CA path length */
103 * Properties of key for generating
106 mbedtls_pk_type_t type; /* type of key to generate */
107 int rsa_keysize; /* length of key in bits */
108 char *key_file_path; /* filename of the key file */
111 extern int generate_webpage_certificate(struct client_state * csp);
112 static char * make_certs_path(const char * conf_dir, const char * file_name, const char * suffix);
113 static int file_exists(const char * path);
114 static int host_to_hash(struct client_state *csp);
115 static int ssl_verify_callback(void *data, mbedtls_x509_crt *crt, int depth, uint32_t *flags);
116 static void free_certificate_chain(struct client_state *csp);
117 static unsigned int get_certificate_mutex_id(struct client_state *csp);
118 static unsigned long get_certificate_serial(struct client_state *csp);
119 static void free_client_ssl_structures(struct client_state *csp);
120 static void free_server_ssl_structures(struct client_state *csp);
121 static int seed_rng(struct client_state *csp);
123 /*********************************************************************
125 * Function : client_use_ssl
127 * Description : Tests if client in current client state structure
128 * should use SSL connection or standard connection.
131 * 1 : csp = Current client state (buffers, headers, etc...)
133 * Returns : If client should use TLS/SSL connection, 1 is returned.
134 * Otherwise 0 is returned.
136 *********************************************************************/
137 extern int client_use_ssl(const struct client_state *csp)
139 return csp->http->client_ssl;
143 /*********************************************************************
145 * Function : server_use_ssl
147 * Description : Tests if server in current client state structure
148 * should use SSL connection or standard connection.
151 * 1 : csp = Current client state (buffers, headers, etc...)
153 * Returns : If server should use TLS/SSL connection, 1 is returned.
154 * Otherwise 0 is returned.
156 *********************************************************************/
157 extern int server_use_ssl(const struct client_state *csp)
159 return csp->http->server_ssl;
163 /*********************************************************************
165 * Function : is_ssl_pending
167 * Description : Tests if there are some waitting data on ssl connection
170 * 1 : ssl = SSL context to test
172 * Returns : 0 => No data are pending
173 * >0 => Pending data length
175 *********************************************************************/
176 extern size_t is_ssl_pending(mbedtls_ssl_context *ssl)
183 return mbedtls_ssl_get_bytes_avail(ssl);
187 /*********************************************************************
189 * Function : ssl_send_data
191 * Description : Sends the content of buf (for n bytes) to given SSL
192 * connection context.
195 * 1 : ssl = SSL context to send data to
196 * 2 : buf = Pointer to data to be sent
197 * 3 : len = Length of data to be sent to the SSL context
199 * Returns : Length of sent data or negative value on error.
201 *********************************************************************/
202 extern int ssl_send_data(mbedtls_ssl_context *ssl, const unsigned char *buf, size_t len)
205 size_t max_fragment_size = 0; /* Maximal length of data in one SSL fragment*/
206 int send_len = 0; /* length of one data part to send */
207 int pos = 0; /* Position of unsent part in buffer */
214 /* Getting maximal length of data sent in one fragment */
215 max_fragment_size = mbedtls_ssl_get_max_frag_len(ssl);
218 * Whole buffer must be sent in many fragments, because each fragment
219 * has its maximal length.
223 /* Compute length of data, that can be send in next fragment */
224 if ((pos + (int)max_fragment_size) > len)
226 send_len = (int)len - pos;
230 send_len = (int)max_fragment_size;
234 * Sending one part of the buffer
236 while ((ret = mbedtls_ssl_write(ssl,
237 (const unsigned char *)(buf + pos),
238 (size_t)send_len)) < 0)
240 if (ret != MBEDTLS_ERR_SSL_WANT_READ &&
241 ret != MBEDTLS_ERR_SSL_WANT_WRITE)
243 char err_buf[ERROR_BUF_SIZE];
245 memset(err_buf, 0, sizeof(err_buf));
246 mbedtls_strerror(ret, err_buf, sizeof(err_buf));
247 log_error(LOG_LEVEL_ERROR,
248 "Sending data over TLS/SSL failed: %s", err_buf);
252 /* Adding count of sent bytes to position in buffer */
253 pos = pos + send_len;
260 /*********************************************************************
262 * Function : ssl_recv_data
264 * Description : Receives data from given SSL context and puts
268 * 1 : ssl = SSL context to receive data from
269 * 2 : buf = Pointer to buffer where data will be written
270 * 3 : max_length = Maximum number of bytes to read
272 * Returns : Number of bytes read, 0 for EOF, or negative
275 *********************************************************************/
276 extern int ssl_recv_data(mbedtls_ssl_context *ssl, unsigned char *buf, size_t max_length)
279 memset(buf, 0, max_length);
282 * Receiving data from SSL context into buffer
286 ret = mbedtls_ssl_read(ssl, buf, max_length);
287 } while (ret == MBEDTLS_ERR_SSL_WANT_READ
288 || ret == MBEDTLS_ERR_SSL_WANT_WRITE);
292 char err_buf[ERROR_BUF_SIZE];
294 memset(err_buf, 0, sizeof(err_buf));
295 mbedtls_strerror(ret, err_buf, sizeof(err_buf));
296 log_error(LOG_LEVEL_ERROR,
297 "Receiving data over TLS/SSL failed: %s", err_buf);
304 /*********************************************************************
306 * Function : ssl_flush_socket
308 * Description : Send any pending "buffered" content with given
309 * SSL connection. Alternative to function flush_socket.
312 * 1 : ssl = SSL context to send buffer to
313 * 2 : iob = The I/O buffer to flush, usually csp->iob.
315 * Returns : On success, the number of bytes send are returned (zero
316 * indicates nothing was sent). On error, -1 is returned.
318 *********************************************************************/
319 extern long ssl_flush_socket(mbedtls_ssl_context *ssl, struct iob *iob)
321 /* Computing length of buffer part to send */
322 long len = iob->eod - iob->cur;
329 /* Sending data to given SSl context */
330 if (ssl_send_data(ssl, (const unsigned char *)iob->cur, (size_t)len) < 0)
334 iob->eod = iob->cur = iob->buf;
339 /*********************************************************************
341 * Function : ssl_debug_callback
343 * Description : Debug callback function for mbedtls library.
344 * Prints info into log file.
347 * 1 : ctx = File to save log in
348 * 2 : level = Debug level
349 * 3 : file = File calling debug message
350 * 4 : line = Line calling debug message
351 * 5 : str = Debug message
355 *********************************************************************/
356 static void ssl_debug_callback(void *ctx, int level, const char *file, int line, const char *str)
360 fprintf((FILE *)ctx, "%s:%04d: %s", file, line, str);
362 log_error(LOG_LEVEL_INFO, "SSL debug message: %s:%04d: %s", file, line, str);
367 /*********************************************************************
369 * Function : create_client_ssl_connection
371 * Description : Creates TLS/SSL secured connection with client
374 * 1 : csp = Current client state (buffers, headers, etc...)
376 * Returns : 0 on success, negative value if connection wasn't created
379 *********************************************************************/
380 extern int create_client_ssl_connection(struct client_state *csp)
382 /* Paths to certificates file and key file */
383 char *key_file = NULL;
384 char *ca_file = NULL;
385 char *cert_file = NULL;
387 char err_buf[ERROR_BUF_SIZE];
389 memset(err_buf, 0, sizeof(err_buf));
392 * Initializing mbedtls structures for TLS/SSL connection
394 mbedtls_net_init(&(csp->mbedtls_client_attr.socket_fd));
395 mbedtls_ssl_init(&(csp->mbedtls_client_attr.ssl));
396 mbedtls_ssl_config_init(&(csp->mbedtls_client_attr.conf));
397 mbedtls_x509_crt_init(&(csp->mbedtls_client_attr.server_cert));
398 mbedtls_pk_init(&(csp->mbedtls_client_attr.prim_key));
399 #if defined(MBEDTLS_SSL_CACHE_C)
400 mbedtls_ssl_cache_init(&(csp->mbedtls_client_attr.cache));
404 * Preparing hash of host for creating certificates
406 ret = host_to_hash(csp);
409 log_error(LOG_LEVEL_ERROR, "Generating hash of host failed: %d", ret);
415 * Preparing paths to certificates files and key file
417 ca_file = csp->config->ca_cert_file;
418 cert_file = make_certs_path(csp->config->certificate_directory,
419 (const char *)csp->http->hash_of_host_hex, CERT_FILE_TYPE);
420 key_file = make_certs_path(csp->config->certificate_directory,
421 (const char *)csp->http->hash_of_host_hex, KEY_FILE_TYPE);
423 if (cert_file == NULL || key_file == NULL)
430 * Generating certificate for requested host. Mutex to prevent
431 * certificate and key inconsistence must be locked.
433 unsigned int cert_mutex_id = get_certificate_mutex_id(csp);
434 privoxy_mutex_lock(&(certificates_mutexes[cert_mutex_id]));
436 ret = generate_webpage_certificate(csp);
439 log_error(LOG_LEVEL_ERROR,
440 "Generate_webpage_certificate failed: %d", ret);
441 privoxy_mutex_unlock(&(certificates_mutexes[cert_mutex_id]));
445 privoxy_mutex_unlock(&(certificates_mutexes[cert_mutex_id]));
458 * Loading CA file, webpage certificate and key files
460 ret = mbedtls_x509_crt_parse_file(&(csp->mbedtls_client_attr.server_cert),
464 mbedtls_strerror(ret, err_buf, sizeof(err_buf));
465 log_error(LOG_LEVEL_ERROR,
466 "Loading webpage certificate %s failed: %s", cert_file, err_buf);
471 ret = mbedtls_x509_crt_parse_file(&(csp->mbedtls_client_attr.server_cert),
475 mbedtls_strerror(ret, err_buf, sizeof(err_buf));
476 log_error(LOG_LEVEL_ERROR,
477 "Loading CA certificate %s failed: %s", ca_file, err_buf);
482 ret = mbedtls_pk_parse_keyfile(&(csp->mbedtls_client_attr.prim_key),
486 mbedtls_strerror(ret, err_buf, sizeof(err_buf));
487 log_error(LOG_LEVEL_ERROR,
488 "Loading and parsing webpage certificate private key %s failed: %s",
495 * Setting SSL parameters
497 ret = mbedtls_ssl_config_defaults(&(csp->mbedtls_client_attr.conf),
498 MBEDTLS_SSL_IS_SERVER, MBEDTLS_SSL_TRANSPORT_STREAM,
499 MBEDTLS_SSL_PRESET_DEFAULT);
502 mbedtls_strerror(ret, err_buf, sizeof(err_buf));
503 log_error(LOG_LEVEL_ERROR,
504 "mbedtls_ssl_config_defaults failed: %s", err_buf);
509 mbedtls_ssl_conf_rng(&(csp->mbedtls_client_attr.conf),
510 mbedtls_ctr_drbg_random, &ctr_drbg);
511 mbedtls_ssl_conf_dbg(&(csp->mbedtls_client_attr.conf),
512 ssl_debug_callback, stdout);
514 #if defined(MBEDTLS_SSL_CACHE_C)
515 mbedtls_ssl_conf_session_cache(&(csp->mbedtls_client_attr.conf),
516 &(csp->mbedtls_client_attr.cache), mbedtls_ssl_cache_get,
517 mbedtls_ssl_cache_set);
521 * Setting certificates
523 ret = mbedtls_ssl_conf_own_cert(&(csp->mbedtls_client_attr.conf),
524 &(csp->mbedtls_client_attr.server_cert),
525 &(csp->mbedtls_client_attr.prim_key));
528 mbedtls_strerror(ret, err_buf, sizeof(err_buf));
529 log_error(LOG_LEVEL_ERROR,
530 "mbedtls_ssl_conf_own_cert failed: %s", err_buf);
535 ret = mbedtls_ssl_setup(&(csp->mbedtls_client_attr.ssl),
536 &(csp->mbedtls_client_attr.conf));
539 mbedtls_strerror(ret, err_buf, sizeof(err_buf));
540 log_error(LOG_LEVEL_ERROR, "mbedtls_ssl_setup failed: %s", err_buf);
545 mbedtls_ssl_set_bio(&(csp->mbedtls_client_attr.ssl),
546 &(csp->mbedtls_client_attr.socket_fd), mbedtls_net_send,
547 mbedtls_net_recv, NULL);
548 mbedtls_ssl_session_reset(&(csp->mbedtls_client_attr.ssl));
551 * Setting socket fd in mbedtls_net_context structure. This structure
552 * can't be set by mbedtls functions, because we already have created
553 * a TCP connection when this function is called.
555 csp->mbedtls_client_attr.socket_fd.fd = csp->cfd;
558 * Handshake with client
560 log_error(LOG_LEVEL_CONNECT,
561 "Performing the TLS/SSL handshake with client. Hash of host: %s",
562 csp->http->hash_of_host_hex);
563 while ((ret = mbedtls_ssl_handshake(&(csp->mbedtls_client_attr.ssl))) != 0)
565 if (ret != MBEDTLS_ERR_SSL_WANT_READ &&
566 ret != MBEDTLS_ERR_SSL_WANT_WRITE)
568 mbedtls_strerror(ret, err_buf, sizeof(err_buf));
569 log_error(LOG_LEVEL_ERROR,
570 "medtls_ssl_handshake with client failed: %s", err_buf);
576 log_error(LOG_LEVEL_CONNECT, "Client successfully connected over TLS/SSL");
577 csp->ssl_with_client_is_opened = 1;
581 * Freeing allocated paths to files
586 /* Freeing structures if connection wasn't created successfully */
589 free_client_ssl_structures(csp);
595 /*********************************************************************
597 * Function : close_client_ssl_connection
599 * Description : Closes TLS/SSL connection with client. This function
600 * checks if this connection is already created.
603 * 1 : csp = Current client state (buffers, headers, etc...)
607 *********************************************************************/
608 extern void close_client_ssl_connection(struct client_state *csp)
612 if (csp->ssl_with_client_is_opened == 0)
618 * Notifying the peer that the connection is being closed.
621 ret = mbedtls_ssl_close_notify(&(csp->mbedtls_client_attr.ssl));
622 } while (ret == MBEDTLS_ERR_SSL_WANT_WRITE);
624 free_client_ssl_structures(csp);
625 csp->ssl_with_client_is_opened = 0;
629 /*********************************************************************
631 * Function : free_client_ssl_structures
633 * Description : Frees structures used for SSL communication with
637 * 1 : csp = Current client state (buffers, headers, etc...)
641 *********************************************************************/
642 static void free_client_ssl_structures(struct client_state *csp)
645 * We can't use function mbedtls_net_free, because this function
646 * inter alia close TCP connection on setted fd. Instead of this
647 * function, we change fd to -1, which is the same what does
648 * rest of mbedtls_net_free function.
650 csp->mbedtls_client_attr.socket_fd.fd = -1;
652 /* Freeing mbedtls structures */
653 mbedtls_x509_crt_free(&(csp->mbedtls_client_attr.server_cert));
654 mbedtls_pk_free(&(csp->mbedtls_client_attr.prim_key));
655 mbedtls_ssl_free(&(csp->mbedtls_client_attr.ssl));
656 mbedtls_ssl_config_free(&(csp->mbedtls_client_attr.conf));
657 #if defined(MBEDTLS_SSL_CACHE_C)
658 mbedtls_ssl_cache_free(&(csp->mbedtls_client_attr.cache));
663 /*********************************************************************
665 * Function : create_server_ssl_connection
667 * Description : Creates TLS/SSL secured connection with server.
670 * 1 : csp = Current client state (buffers, headers, etc...)
672 * Returns : 0 on success, negative value if connection wasn't created
675 *********************************************************************/
676 extern int create_server_ssl_connection(struct client_state *csp)
679 char err_buf[ERROR_BUF_SIZE];
680 char *trusted_cas_file = NULL;
681 int auth_mode = MBEDTLS_SSL_VERIFY_REQUIRED;
683 memset(err_buf, 0, sizeof(err_buf));
685 csp->server_cert_verification_result = SSL_CERT_NOT_VERIFIED;
686 csp->server_certs_chain.next = NULL;
688 /* Setting path to file with trusted CAs */
689 trusted_cas_file = csp->config->trusted_cas_file;
692 * Initializing mbedtls structures for TLS/SSL connection
694 mbedtls_net_init(&(csp->mbedtls_server_attr.socket_fd));
695 mbedtls_ssl_init(&(csp->mbedtls_server_attr.ssl));
696 mbedtls_ssl_config_init(&(csp->mbedtls_server_attr.conf));
697 mbedtls_x509_crt_init( &(csp->mbedtls_server_attr.ca_cert));
700 * Setting socket fd in mbedtls_net_context structure. This structure
701 * can't be set by mbedtls functions, because we already have created
702 * TCP connection when calling this function.
704 csp->mbedtls_server_attr.socket_fd.fd = csp->server_connection.sfd;
717 * Loading file with trusted CAs
719 ret = mbedtls_x509_crt_parse_file(&(csp->mbedtls_server_attr.ca_cert),
723 mbedtls_strerror(ret, err_buf, sizeof(err_buf));
724 log_error(LOG_LEVEL_ERROR, "Loading trusted CAs file %s failed: %s",
725 trusted_cas_file, err_buf);
731 * Set TLS/SSL options
733 ret = mbedtls_ssl_config_defaults(&(csp->mbedtls_server_attr.conf),
734 MBEDTLS_SSL_IS_CLIENT,
735 MBEDTLS_SSL_TRANSPORT_STREAM,
736 MBEDTLS_SSL_PRESET_DEFAULT);
739 mbedtls_strerror(ret, err_buf, sizeof(err_buf));
740 log_error(LOG_LEVEL_ERROR, "mbedtls_ssl_config_defaults failed: %s",
747 * Setting how strict should certificate verification be and other
748 * parameters for certificate verification
750 if (csp->dont_verify_certificate)
752 auth_mode = MBEDTLS_SSL_VERIFY_NONE;
755 mbedtls_ssl_conf_authmode(&(csp->mbedtls_server_attr.conf), auth_mode);
756 mbedtls_ssl_conf_ca_chain(&(csp->mbedtls_server_attr.conf),
757 &(csp->mbedtls_server_attr.ca_cert), NULL);
759 /* Setting callback function for certificates verification */
760 mbedtls_ssl_conf_verify(&(csp->mbedtls_server_attr.conf),
761 ssl_verify_callback, (void *)csp);
763 mbedtls_ssl_conf_rng(&(csp->mbedtls_server_attr.conf),
764 mbedtls_ctr_drbg_random, &ctr_drbg);
765 mbedtls_ssl_conf_dbg(&(csp->mbedtls_server_attr.conf),
766 ssl_debug_callback, stdout);
768 ret = mbedtls_ssl_setup(&(csp->mbedtls_server_attr.ssl),
769 &(csp->mbedtls_server_attr.conf));
772 mbedtls_strerror(ret, err_buf, sizeof(err_buf));
773 log_error(LOG_LEVEL_ERROR, "mbedtls_ssl_setup failed: %s", err_buf);
779 * Set the hostname to check against the received server certificate
781 ret = mbedtls_ssl_set_hostname(&(csp->mbedtls_server_attr.ssl),
785 mbedtls_strerror(ret, err_buf, sizeof(err_buf));
786 log_error(LOG_LEVEL_ERROR, "mbedtls_ssl_set_hostname failed: %s",
792 mbedtls_ssl_set_bio(&(csp->mbedtls_server_attr.ssl),
793 &(csp->mbedtls_server_attr.socket_fd), mbedtls_net_send,
794 mbedtls_net_recv, NULL);
797 * Handshake with server
799 log_error(LOG_LEVEL_CONNECT,
800 "Performing the TLS/SSL handshake with server");
802 while ((ret = mbedtls_ssl_handshake(&(csp->mbedtls_server_attr.ssl))) != 0)
804 if (ret != MBEDTLS_ERR_SSL_WANT_READ
805 && ret != MBEDTLS_ERR_SSL_WANT_WRITE)
807 mbedtls_strerror(ret, err_buf, sizeof(err_buf));
809 if (ret == MBEDTLS_ERR_X509_CERT_VERIFY_FAILED)
811 log_error(LOG_LEVEL_ERROR,
812 "Server certificate verification failed: %s", err_buf);
813 csp->server_cert_verification_result =
814 mbedtls_ssl_get_verify_result(&(csp->mbedtls_server_attr.ssl));
820 log_error(LOG_LEVEL_ERROR,
821 "mbedtls_ssl_handshake with server failed: %s", err_buf);
828 log_error(LOG_LEVEL_CONNECT, "Server successfully connected over TLS/SSL");
831 * Server certificate chain is valid, so we can clean
832 * chain, because we will not send it to client.
834 free_certificate_chain(csp);
836 csp->ssl_with_server_is_opened = 1;
837 csp->server_cert_verification_result =
838 mbedtls_ssl_get_verify_result(&(csp->mbedtls_server_attr.ssl));
841 /* Freeing structures if connection wasn't created successfully */
844 free_server_ssl_structures(csp);
851 /*********************************************************************
853 * Function : close_server_ssl_connection
855 * Description : Closes TLS/SSL connection with server. This function
856 * checks if this connection is already opened.
859 * 1 : csp = Current client state (buffers, headers, etc...)
863 *********************************************************************/
864 static void close_server_ssl_connection(struct client_state *csp)
868 if (csp->ssl_with_server_is_opened == 0)
874 * Notifying the peer that the connection is being closed.
877 ret = mbedtls_ssl_close_notify(&(csp->mbedtls_server_attr.ssl));
878 } while (ret == MBEDTLS_ERR_SSL_WANT_WRITE);
880 free_server_ssl_structures(csp);
881 csp->ssl_with_server_is_opened = 0;
885 /*********************************************************************
887 * Function : free_server_ssl_structures
889 * Description : Frees structures used for SSL communication with server
892 * 1 : csp = Current client state (buffers, headers, etc...)
896 *********************************************************************/
897 static void free_server_ssl_structures(struct client_state *csp)
900 * We can't use function mbedtls_net_free, because this function
901 * inter alia close TCP connection on setted fd. Instead of this
902 * function, we change fd to -1, which is the same what does
903 * rest of mbedtls_net_free function.
905 csp->mbedtls_client_attr.socket_fd.fd = -1;
907 mbedtls_x509_crt_free(&(csp->mbedtls_server_attr.ca_cert));
908 mbedtls_ssl_free(&(csp->mbedtls_server_attr.ssl));
909 mbedtls_ssl_config_free(&(csp->mbedtls_server_attr.conf));
913 /*********************************************************************
915 * Function : close_client_and_server_ssl_connections
917 * Description : Checks if client or server should use secured
918 * connection over SSL and if so, closes all of them.
921 * 1 : csp = Current client state (buffers, headers, etc...)
925 *********************************************************************/
926 extern void close_client_and_server_ssl_connections(struct client_state *csp)
928 if (client_use_ssl(csp) == 1)
930 close_client_ssl_connection(csp);
932 if (server_use_ssl(csp) == 1)
934 close_server_ssl_connection(csp);
938 /*====================== Certificates ======================*/
940 /*********************************************************************
942 * Function : write_certificate
944 * Description : Writes certificate into file.
947 * 1 : crt = certificate to write into file
948 * 2 : output_file = path to save certificate file
949 * 3 : f_rng = mbedtls_ctr_drbg_random
950 * 4 : p_rng = mbedtls_ctr_drbg_context
952 * Returns : Length of written certificate on success or negative value
955 *********************************************************************/
956 static int write_certificate(mbedtls_x509write_cert *crt, const char *output_file,
957 int(*f_rng)(void *, unsigned char *, size_t), void *p_rng)
961 unsigned char cert_buf[CERTIFICATE_BUF_SIZE + 1]; /* Buffer for certificate in PEM format + terminating NULL */
963 char err_buf[ERROR_BUF_SIZE];
965 memset(err_buf, 0, sizeof(err_buf));
966 memset(cert_buf, 0, sizeof(cert_buf));
969 * Writing certificate into PEM string. If buffer is too small, fuction
970 * returns specific error and no buffer overflow can happen.
972 if ((ret = mbedtls_x509write_crt_pem(crt, cert_buf,
973 sizeof(cert_buf) - 1, f_rng, p_rng)) != 0)
975 mbedtls_strerror(ret, err_buf, sizeof(err_buf));
976 log_error(LOG_LEVEL_ERROR,
977 "Writing certificate into buffer failed: %s", err_buf);
981 len = strlen((char *)cert_buf);
984 * Saving certificate into file
986 if ((f = fopen(output_file, "w")) == NULL)
988 log_error(LOG_LEVEL_ERROR, "Opening file %s to save certificate failed",
993 if (fwrite(cert_buf, 1, len, f) != len)
995 log_error(LOG_LEVEL_ERROR,
996 "Writing certificate into file %s failed", output_file);
1007 /*********************************************************************
1009 * Function : write_private_key
1011 * Description : Writes private key into file and copies saved
1012 * content into given pointer to string. If function
1013 * returns 0 for success, this copy must be freed by
1017 * 1 : key = key to write into file
1018 * 2 : ret_buf = pointer to string with created key file content
1019 * 3 : key_file_path = path where to save key file
1021 * Returns : Length of written private key on success or negative value
1024 *********************************************************************/
1025 static int write_private_key(mbedtls_pk_context *key, unsigned char **ret_buf,
1026 const char *key_file_path)
1028 size_t len = 0; /* Length of created key */
1029 FILE *f = NULL; /* File to save certificate */
1031 char err_buf[ERROR_BUF_SIZE];
1033 memset(err_buf, 0, sizeof(err_buf));
1035 /* Initializing buffer for key file content */
1036 *ret_buf = (unsigned char *)malloc(PRIVATE_KEY_BUF_SIZE + 1);
1037 if (*ret_buf == NULL)
1039 log_error(LOG_LEVEL_ERROR,
1040 "Creating buffer for private key failed: malloc fail");
1044 memset(*ret_buf, 0, PRIVATE_KEY_BUF_SIZE + 1);
1047 * Writing private key into PEM string
1049 if ((ret = mbedtls_pk_write_key_pem(key, *ret_buf, PRIVATE_KEY_BUF_SIZE)) != 0)
1051 mbedtls_strerror(ret, err_buf, sizeof(err_buf));
1052 log_error(LOG_LEVEL_ERROR,
1053 "Writing private key into PEM string failed: %s", err_buf);
1057 len = strlen((char *)*ret_buf);
1060 * Saving key into file
1062 if ((f = fopen(key_file_path, "wb")) == NULL)
1064 log_error(LOG_LEVEL_ERROR,
1065 "Opening file %s to save private key failed: %E",
1071 if (fwrite(*ret_buf, 1, len, f) != len)
1074 log_error(LOG_LEVEL_ERROR,
1075 "Writing private key into file %s failed",
1094 /*********************************************************************
1096 * Function : generate_key
1098 * Description : Tests if private key for host saved in csp already
1099 * exists. If this file doesn't exists, a new key is
1100 * generated and saved in a file. The generated key is also
1101 * copied into given parameter key_buf, which must be then
1102 * freed by caller. If file with key exists, key_buf
1103 * contain NULL and no private key is generated.
1106 * 1 : key_buf = buffer to save new generated key
1107 * 2 : csp = Current client state (buffers, headers, etc...)
1109 * Returns : -1 => Error while generating private key
1110 * 0 => Key already exists
1111 * >0 => Length of generated private key
1113 *********************************************************************/
1114 static int generate_key(unsigned char **key_buf, struct client_state *csp)
1116 mbedtls_pk_context key;
1117 key_options key_opt;
1119 char err_buf[ERROR_BUF_SIZE];
1121 key_opt.key_file_path = NULL;
1122 memset(err_buf, 0, sizeof(err_buf));
1125 * Initializing structures for key generating
1127 mbedtls_pk_init(&key);
1130 * Preparing path for key file and other properties for generating key
1132 key_opt.type = MBEDTLS_PK_RSA;
1133 key_opt.rsa_keysize = RSA_KEYSIZE;
1135 key_opt.key_file_path = make_certs_path(csp->config->certificate_directory,
1136 (char *)csp->http->hash_of_host_hex, KEY_FILE_TYPE);
1137 if (key_opt.key_file_path == NULL)
1144 * Test if key already exists. If so, we don't have to create it again.
1146 if (file_exists(key_opt.key_file_path) == 1)
1155 ret = seed_rng(csp);
1163 * Setting attributes of private key and generating it
1165 if ((ret = mbedtls_pk_setup(&key,
1166 mbedtls_pk_info_from_type(key_opt.type))) != 0)
1168 mbedtls_strerror(ret, err_buf, sizeof(err_buf));
1169 log_error(LOG_LEVEL_ERROR, "mbedtls_pk_setup failed: %s", err_buf);
1174 ret = mbedtls_rsa_gen_key(mbedtls_pk_rsa(key), mbedtls_ctr_drbg_random,
1175 &ctr_drbg, (unsigned)key_opt.rsa_keysize, RSA_KEY_PUBLIC_EXPONENT);
1178 mbedtls_strerror(ret, err_buf, sizeof(err_buf));
1179 log_error(LOG_LEVEL_ERROR, "Key generating failed: %s", err_buf);
1185 * Exporting private key into file
1187 if ((ret = write_private_key(&key, key_buf, key_opt.key_file_path)) < 0)
1189 log_error(LOG_LEVEL_ERROR,
1190 "Writing private key into file %s failed", key_opt.key_file_path);
1197 * Freeing used variables
1199 freez(key_opt.key_file_path);
1201 mbedtls_pk_free(&key);
1207 /*********************************************************************
1209 * Function : generate_webpage_certificate
1211 * Description : Creates certificate file in presetted directory.
1212 * If certificate already exists, no other certificate
1213 * will be created. Subject of certificate is named
1214 * by csp->http->host from parameter. This function also
1215 * triggers generating of private key for new certificate.
1218 * 1 : csp = Current client state (buffers, headers, etc...)
1220 * Returns : -1 => Error while creating certificate.
1221 * 0 => Certificate alreaday exist.
1222 * >0 => Length of created certificate.
1224 *********************************************************************/
1225 extern int generate_webpage_certificate(struct client_state * csp)
1227 mbedtls_x509_crt issuer_cert;
1228 mbedtls_pk_context loaded_issuer_key, loaded_subject_key;
1229 mbedtls_pk_context *issuer_key = &loaded_issuer_key;
1230 mbedtls_pk_context *subject_key = &loaded_subject_key;
1231 mbedtls_x509write_cert cert;
1234 unsigned char *key_buf = NULL; /* Buffer for created key */
1237 char err_buf[ERROR_BUF_SIZE];
1238 cert_options cert_opt;
1240 memset(err_buf, 0, sizeof(err_buf));
1242 /* Paths to keys and certificates needed to create certificate */
1243 cert_opt.issuer_key = NULL;
1244 cert_opt.subject_key = NULL;
1245 cert_opt.issuer_crt = NULL;
1246 cert_opt.output_file = NULL;
1249 * Create key for requested host
1251 int subject_key_len = generate_key(&key_buf, csp);
1252 if (subject_key_len < 0)
1254 log_error(LOG_LEVEL_ERROR, "Key generating failed");
1259 * Initializing structures for certificate generating
1261 mbedtls_x509write_crt_init(&cert);
1262 mbedtls_x509write_crt_set_md_alg( &cert, CERT_SIGNATURE_ALGORITHM);
1263 mbedtls_pk_init(&loaded_issuer_key);
1264 mbedtls_pk_init(&loaded_subject_key);
1265 mbedtls_mpi_init(&serial);
1266 mbedtls_x509_crt_init(&issuer_cert);
1269 * Presetting parameters for certificate. We must compute total length
1272 size_t cert_params_len = strlen(CERT_PARAM_COMMON_NAME) +
1273 strlen(CERT_PARAM_ORGANIZATION) + strlen(CERT_PARAM_COUNTRY) +
1274 strlen(CERT_PARAM_ORG_UNIT) +
1275 3 * strlen(csp->http->host) + 1;
1276 char cert_params[cert_params_len];
1277 memset(cert_params, 0, cert_params_len);
1280 * Converting unsigned long serial number to char * serial number.
1281 * We must compute length of serial number in string + terminating null.
1283 unsigned long certificate_serial = get_certificate_serial(csp);
1284 int serial_num_size = snprintf(NULL, 0, "%lu", certificate_serial) + 1;
1285 if (serial_num_size <= 0)
1287 serial_num_size = 1;
1290 char serial_num_text[serial_num_size]; /* Buffer for serial number */
1291 ret = snprintf(serial_num_text, (size_t)serial_num_size, "%lu", certificate_serial);
1292 if (ret < 0 || ret >= serial_num_size)
1294 log_error(LOG_LEVEL_ERROR,
1295 "Converting certificate serial number into string failed");
1301 * Preparing parameters for certificate
1303 strlcpy(cert_params, CERT_PARAM_COMMON_NAME, cert_params_len);
1304 strlcat(cert_params, csp->http->host, cert_params_len);
1305 strlcat(cert_params, CERT_PARAM_ORGANIZATION, cert_params_len);
1306 strlcat(cert_params, csp->http->host, cert_params_len);
1307 strlcat(cert_params, CERT_PARAM_ORG_UNIT, cert_params_len);
1308 strlcat(cert_params, csp->http->host, cert_params_len);
1309 strlcat(cert_params, CERT_PARAM_COUNTRY, cert_params_len);
1311 cert_opt.issuer_crt = csp->config->ca_cert_file;
1312 cert_opt.issuer_key = csp->config->ca_key_file;
1313 cert_opt.subject_key = make_certs_path(csp->config->certificate_directory,
1314 (const char *)csp->http->hash_of_host_hex, KEY_FILE_TYPE);
1315 cert_opt.output_file = make_certs_path(csp->config->certificate_directory,
1316 (const char *)csp->http->hash_of_host_hex, CERT_FILE_TYPE);
1318 if (cert_opt.subject_key == NULL || cert_opt.output_file == NULL)
1324 cert_opt.subject_pwd = CERT_SUBJECT_PASSWORD;
1325 cert_opt.issuer_pwd = csp->config->ca_password;
1326 cert_opt.subject_name = cert_params;
1327 cert_opt.not_before = GENERATED_CERT_VALID_FROM;
1328 cert_opt.not_after = GENERATED_CERT_VALID_TO;
1329 cert_opt.serial = serial_num_text;
1331 cert_opt.max_pathlen = -1;
1334 * Test if certificate exists and private key was already created
1336 if (file_exists(cert_opt.output_file) == 1 && subject_key_len == 0)
1345 ret = seed_rng(csp);
1353 * Parse serial to MPI
1355 ret = mbedtls_mpi_read_string(&serial, 10, cert_opt.serial);
1358 mbedtls_strerror(ret, err_buf, sizeof(err_buf));
1359 log_error(LOG_LEVEL_ERROR,
1360 "mbedtls_mpi_read_string failed: %s", err_buf);
1366 * Loading certificates
1368 ret = mbedtls_x509_crt_parse_file(&issuer_cert, cert_opt.issuer_crt);
1371 mbedtls_strerror(ret, err_buf, sizeof(err_buf));
1372 log_error(LOG_LEVEL_ERROR, "Loading issuer certificate %s failed: %s",
1373 cert_opt.issuer_crt, err_buf);
1378 ret = mbedtls_x509_dn_gets(cert_opt.issuer_name,
1379 sizeof(cert_opt.issuer_name), &issuer_cert.subject);
1382 mbedtls_strerror(ret, err_buf, sizeof(err_buf));
1383 log_error(LOG_LEVEL_ERROR, "mbedtls_x509_dn_gets failed: %s", err_buf);
1389 * Loading keys from file or from buffer
1391 if (key_buf != NULL && subject_key_len > 0)
1393 /* Key was created in this function and is stored in buffer */
1394 ret = mbedtls_pk_parse_key(&loaded_subject_key, key_buf,
1395 (size_t)(subject_key_len + 1), (unsigned const char *)
1396 cert_opt.subject_pwd, strlen(cert_opt.subject_pwd));
1400 /* Key wasn't created in this function, because it already existed */
1401 ret = mbedtls_pk_parse_keyfile(&loaded_subject_key,
1402 cert_opt.subject_key, cert_opt.subject_pwd);
1407 mbedtls_strerror(ret, err_buf, sizeof(err_buf));
1408 log_error(LOG_LEVEL_ERROR, "Parsing subject key %s failed: %s",
1409 cert_opt.subject_key, err_buf);
1414 ret = mbedtls_pk_parse_keyfile(&loaded_issuer_key, cert_opt.issuer_key,
1415 cert_opt.issuer_pwd);
1418 mbedtls_strerror(ret, err_buf, sizeof(err_buf));
1419 log_error(LOG_LEVEL_ERROR,
1420 "Parsing issuer key %s failed: %s", cert_opt.issuer_key, err_buf);
1426 * Check if key and issuer certificate match
1428 if (!mbedtls_pk_can_do(&issuer_cert.pk, MBEDTLS_PK_RSA) ||
1429 mbedtls_mpi_cmp_mpi(&mbedtls_pk_rsa(issuer_cert.pk)->N,
1430 &mbedtls_pk_rsa(*issuer_key)->N) != 0 ||
1431 mbedtls_mpi_cmp_mpi( &mbedtls_pk_rsa(issuer_cert.pk)->E,
1432 &mbedtls_pk_rsa(*issuer_key )->E) != 0)
1434 log_error(LOG_LEVEL_ERROR,
1435 "Issuer key doesn't match issuer certificate");
1440 mbedtls_x509write_crt_set_subject_key(&cert, subject_key);
1441 mbedtls_x509write_crt_set_issuer_key(&cert, issuer_key);
1444 * Setting parameters of signed certificate
1446 ret = mbedtls_x509write_crt_set_subject_name(&cert, cert_opt.subject_name);
1449 mbedtls_strerror(ret, err_buf, sizeof(err_buf));
1450 log_error(LOG_LEVEL_ERROR,
1451 "Setting subject name in signed certificate failed: %s", err_buf);
1456 ret = mbedtls_x509write_crt_set_issuer_name(&cert, cert_opt.issuer_name);
1459 mbedtls_strerror(ret, err_buf, sizeof(err_buf));
1460 log_error(LOG_LEVEL_ERROR,
1461 "Setting issuer name in signed certificate failed: %s", err_buf);
1466 ret = mbedtls_x509write_crt_set_serial(&cert, &serial);
1469 mbedtls_strerror(ret, err_buf, sizeof(err_buf));
1470 log_error(LOG_LEVEL_ERROR,
1471 "Setting serial number in signed certificate failed: %s", err_buf);
1476 ret = mbedtls_x509write_crt_set_validity(&cert, cert_opt.not_before,
1477 cert_opt.not_after);
1480 mbedtls_strerror(ret, err_buf, sizeof(err_buf));
1481 log_error(LOG_LEVEL_ERROR,
1482 "Setting validity in signed certificate failed: %s", err_buf);
1488 * Setting the basicConstraints extension for certificate
1490 ret = mbedtls_x509write_crt_set_basic_constraints(&cert, cert_opt.is_ca,
1491 cert_opt.max_pathlen);
1494 mbedtls_strerror(ret, err_buf, sizeof(err_buf));
1495 log_error(LOG_LEVEL_ERROR, "Setting the basicConstraints extension "
1496 "in signed certificate failed: %s", err_buf);
1501 #if defined(MBEDTLS_SHA1_C)
1502 /* Setting the subjectKeyIdentifier extension for certificate */
1503 ret = mbedtls_x509write_crt_set_subject_key_identifier(&cert);
1506 mbedtls_strerror(ret, err_buf, sizeof(err_buf));
1507 log_error(LOG_LEVEL_ERROR, "mbedtls_x509write_crt_set_subject_key_"
1508 "identifier failed: %s", err_buf);
1513 /* Setting the authorityKeyIdentifier extension for certificate */
1514 ret = mbedtls_x509write_crt_set_authority_key_identifier(&cert);
1517 mbedtls_strerror(ret, err_buf, sizeof(err_buf));
1518 log_error(LOG_LEVEL_ERROR, "mbedtls_x509write_crt_set_authority_key_"
1519 "identifier failed: %s", err_buf);
1523 #endif /* MBEDTLS_SHA1_C */
1526 * Writing certificate into file
1528 ret = write_certificate(&cert, cert_opt.output_file,
1529 mbedtls_ctr_drbg_random, &ctr_drbg);
1532 log_error(LOG_LEVEL_ERROR, "Writing certificate into file failed");
1538 * Freeing used structures
1540 mbedtls_x509write_crt_free(&cert);
1541 mbedtls_pk_free(&loaded_subject_key);
1542 mbedtls_pk_free(&loaded_issuer_key);
1543 mbedtls_mpi_free(&serial);
1544 mbedtls_x509_crt_free(&issuer_cert);
1546 freez(cert_opt.subject_key);
1547 freez(cert_opt.output_file);
1554 /*********************************************************************
1556 * Function : make_certs_path
1558 * Description : Creates path to file from three pieces. This fuction
1559 * takes parameters and puts them in one new mallocated
1560 * char * in correct order. Returned variable must be freed
1561 * by caller. This function is mainly used for creating
1562 * paths of certificates and keys files.
1565 * 1 : conf_dir = Name/path of directory where is the file.
1566 * '.' can be used for current directory.
1567 * 2 : file_name = Name of file in conf_dir without suffix.
1568 * 3 : suffix = Suffix of given file_name.
1570 * Returns : path => Path was built up successfully
1571 * NULL => Path can't be built up
1573 *********************************************************************/
1574 static char *make_certs_path(const char *conf_dir, const char *file_name,
1577 /* Test if all given parameters are valid */
1578 if (conf_dir == NULL || *conf_dir == '\0' || file_name == NULL ||
1579 *file_name == '\0' || suffix == NULL || *suffix == '\0')
1581 log_error(LOG_LEVEL_ERROR,
1582 "make_certs_path failed: bad input parameters");
1587 size_t path_size = strlen(conf_dir)
1588 + strlen(file_name) + strlen(suffix) + 2;
1590 /* Setting delimiter and editing path length */
1591 #if defined(_WIN32) || defined(__OS2__)
1592 char delim[] = "\\";
1594 #else /* ifndef _WIN32 || __OS2__ */
1596 #endif /* ifndef _WIN32 || __OS2__ */
1599 * Building up path from many parts
1602 if (*conf_dir != '/' && basedir && *basedir)
1605 * Replacing conf_dir with basedir. This new variable contains
1606 * absolute path to cwd.
1608 path_size += strlen(basedir) + 2;
1609 path = (char *)malloc(path_size);
1612 log_error(LOG_LEVEL_ERROR, "make_certs_path failed: malloc fail");
1615 memset(path, 0, path_size);
1617 strlcpy(path, basedir, path_size);
1618 strlcat(path, delim, path_size);
1619 strlcat(path, conf_dir, path_size);
1620 strlcat(path, delim, path_size);
1621 strlcat(path, file_name, path_size);
1622 strlcat(path, suffix, path_size);
1625 #endif /* defined unix */
1627 path = (char *)malloc(path_size);
1630 log_error(LOG_LEVEL_ERROR, "make_certs_path failed: malloc fail");
1633 memset(path, 0, path_size);
1635 strlcpy(path, conf_dir, path_size);
1636 strlcat(path, delim, path_size);
1637 strlcat(path, file_name, path_size);
1638 strlcat(path, suffix, path_size);
1645 /*********************************************************************
1647 * Function : get_certificate_mutex_id
1649 * Description : Computes mutex id from host name hash. This hash must
1650 * be already saved in csp structure
1653 * 1 : csp = Current client state (buffers, headers, etc...)
1655 * Returns : Mutex id for given host name
1657 *********************************************************************/
1658 static unsigned int get_certificate_mutex_id(struct client_state *csp) {
1659 #ifdef LIMIT_MUTEX_NUMBER
1660 return (unsigned int)(csp->http->hash_of_host[0] % 32);
1662 return (unsigned int)(csp->http->hash_of_host[1]
1663 + 256 * (int)csp->http->hash_of_host[0]);
1664 #endif /* LIMIT_MUTEX_NUMBER */
1668 /*********************************************************************
1670 * Function : get_certificate_serial
1672 * Description : Computes serial number for new certificate from host
1673 * name hash. This hash must be already saved in csp
1677 * 1 : csp = Current client state (buffers, headers, etc...)
1679 * Returns : Serial number for new certificate
1681 *********************************************************************/
1682 static unsigned long get_certificate_serial(struct client_state *csp) {
1683 unsigned long exp = 1;
1684 unsigned long serial = 0;
1686 int i = CERT_SERIAL_NUM_LENGTH;
1687 /* Length of hash is 16 bytes, we must avoid to read next chars */
1699 serial += exp * (unsigned)csp->http->hash_of_host[i];
1706 /*********************************************************************
1708 * Function : ssl_send_certificate_error
1710 * Description : Sends info about invalid server certificate to client.
1711 * Sent message is including all trusted chain certificates,
1712 * that can be downloaded in web browser.
1715 * 1 : csp = Current client state (buffers, headers, etc...)
1719 *********************************************************************/
1720 extern void ssl_send_certificate_error(struct client_state *csp)
1722 size_t message_len = 0;
1724 struct certs_chain *cert = NULL;
1726 /* Header of message with certificate informations */
1727 const char message_begin[] =
1728 "HTTP/1.1 200 OK\r\n"
1729 "Content-Type: text/html\r\n"
1730 "Connection: close\r\n\r\n"
1731 "<html><body><h1>Invalid server certificate</h1><p>Reason: ";
1732 const char message_end[] = "</body></html>\r\n\r\n";
1733 char reason[INVALID_CERT_INFO_BUF_SIZE];
1734 memset(reason, 0, sizeof(reason));
1736 /* Get verification message from verification return code */
1737 mbedtls_x509_crt_verify_info(reason, sizeof(reason), " ",
1738 csp->server_cert_verification_result);
1741 * Computing total length of message with all certificates inside
1743 message_len = strlen(message_begin) + strlen(message_end)
1744 + strlen(reason) + strlen("</p>") + 1;
1746 cert = &(csp->server_certs_chain);
1747 while (cert->next != NULL)
1749 size_t base64_len = 4 * ((strlen(cert->file_buf) + 2) / 3) + 1;
1751 message_len += strlen(cert->text_buf) + strlen("<pre></pre>\n")
1752 + base64_len + strlen("<a href=\"data:application"
1753 "/x-x509-ca-cert;base64,\">Download certificate</a>");
1758 * Joining all blocks in one long message
1760 char message[message_len];
1761 memset(message, 0, message_len);
1763 strlcpy(message, message_begin, message_len);
1764 strlcat(message, reason , message_len);
1765 strlcat(message, "</p>" , message_len);
1767 cert = &(csp->server_certs_chain);
1768 while (cert->next != NULL)
1771 size_t base64_len = 4 * ((strlen(cert->file_buf) + 2) / 3) + 1; /* +1 for terminating null*/
1772 char base64_buf[base64_len];
1773 memset(base64_buf, 0, base64_len);
1775 /* Encoding certificate into base64 code */
1776 ret = mbedtls_base64_encode((unsigned char*)base64_buf,
1777 base64_len, &olen, (const unsigned char*)cert->file_buf,
1778 strlen(cert->file_buf));
1781 log_error(LOG_LEVEL_ERROR,
1782 "Encoding to base64 failed, buffer is to small");
1785 strlcat(message, "<pre>", message_len);
1786 strlcat(message, cert->text_buf, message_len);
1787 strlcat(message, "</pre>\n", message_len);
1791 strlcat(message, "<a href=\"data:application/x-x509-ca-cert;base64,",
1793 strlcat(message, base64_buf, message_len);
1794 strlcat(message, "\">Download certificate</a>", message_len);
1799 strlcat(message, message_end, message_len);
1802 * Sending final message to client
1804 ssl_send_data(&(csp->mbedtls_client_attr.ssl),
1805 (const unsigned char *)message, strlen(message));
1807 * Waiting before closing connection. Some browsers doesn't show received
1808 * message if there isn't this delay.
1812 free_certificate_chain(csp);
1816 /*********************************************************************
1818 * Function : ssl_verify_callback
1820 * Description : This is a callback function for certificate verification.
1821 * It's called for all certificates in server certificate
1822 * trusted chain and it's preparing information about this
1823 * certificates. Prepared informations can be used to inform
1824 * user about invalid certificates.
1827 * 1 : csp_void = Current client state (buffers, headers, etc...)
1828 * 2 : crt = certificate from trusted chain
1829 * 3 : depth = depth in trusted chain
1830 * 4 : flags = certificate flags
1832 * Returns : 0 on success and negative value on error
1834 *********************************************************************/
1835 static int ssl_verify_callback(void *csp_void, mbedtls_x509_crt *crt,
1836 int depth, uint32_t *flags)
1838 struct client_state *csp = (struct client_state *)csp_void;
1839 struct certs_chain *last = &(csp->server_certs_chain);
1844 * Searching for last item in certificates linked list
1846 while (last->next != NULL)
1852 * Preparing next item in linked list for next certificate
1853 * If malloc fails, we are continuing without this certificate
1855 last->next = (struct certs_chain *)malloc(sizeof(struct certs_chain));
1856 if (last->next != NULL)
1858 last->next->next = NULL;
1859 memset(last->next->text_buf, 0, sizeof(last->next->text_buf));
1860 memset(last->next->file_buf, 0, sizeof(last->next->file_buf));
1863 * Saving certificate file into buffer
1865 if ((ret = mbedtls_pem_write_buffer(PEM_BEGIN_CRT, PEM_END_CRT,
1866 crt->raw.p, crt->raw.len, (unsigned char *)last->file_buf,
1867 sizeof(last->file_buf)-1, &olen)) != 0)
1873 * Saving certificate information into buffer
1875 mbedtls_x509_crt_info(last->text_buf, sizeof(last->text_buf) - 1,
1876 CERT_INFO_PREFIX, crt);
1880 log_error(LOG_LEVEL_ERROR,
1881 "Malloc memory for server certificate informations failed");
1889 /*********************************************************************
1891 * Function : free_certificate_chain
1893 * Description : Frees certificates linked list. This linked list is
1894 * used to save informations about certificates in
1898 * 1 : csp = Current client state (buffers, headers, etc...)
1902 *********************************************************************/
1903 static void free_certificate_chain(struct client_state *csp)
1905 struct certs_chain *cert = csp->server_certs_chain.next;
1907 /* Cleaning buffers */
1908 memset(csp->server_certs_chain.text_buf, 0,
1909 sizeof(csp->server_certs_chain.text_buf));
1910 memset(csp->server_certs_chain.text_buf, 0,
1911 sizeof(csp->server_certs_chain.file_buf));
1912 csp->server_certs_chain.next = NULL;
1914 /* Freeing memory in whole linked list */
1919 struct certs_chain *cert_for_free = cert;
1921 freez(cert_for_free);
1922 } while (cert != NULL);
1927 /*********************************************************************
1929 * Function : file_exists
1931 * Description : Tests if file exists and is readable.
1934 * 1 : path = Path to tested file.
1936 * Returns : 1 => File exists and is readable.
1937 * 0 => File doesn't exist or is not readable.
1939 *********************************************************************/
1940 static int file_exists(const char *path)
1943 if ((f = fopen(path, "r")) != NULL)
1953 /*********************************************************************
1955 * Function : host_to_hash
1957 * Description : Creates MD5 hash from host name. Host name is loaded
1958 * from structure csp and saved again into it.
1961 * 1 : csp = Current client state (buffers, headers, etc...)
1963 * Returns : 1 => Error while creating hash
1964 * 0 => Hash created successfully
1966 *********************************************************************/
1967 static int host_to_hash(struct client_state * csp)
1971 #if !defined(MBEDTLS_MD5_C)
1972 log_error(LOG_LEVEL_ERROR, "MBEDTLS_MD5_C is not defined. Can't create"
1973 "MD5 hash for certificate and key name.");
1976 memset(csp->http->hash_of_host, 0, sizeof(csp->http->hash_of_host));
1977 mbedtls_md5((unsigned char *)csp->http->host, strlen(csp->http->host),
1978 csp->http->hash_of_host);
1980 /* Converting hash into string with hex */
1984 if ((ret = sprintf((char *)csp->http->hash_of_host_hex + 2 * i, "%02x",
1985 csp->http->hash_of_host[i])) < 0)
1987 log_error(LOG_LEVEL_ERROR, "Sprintf return value: %d", ret);
1993 #endif /* MBEDTLS_MD5_C */
1997 /*********************************************************************
1999 * Function : tunnel_established_successfully
2001 * Description : Check if parent proxy server response contains
2002 * informations about successfully created connection with
2003 * destination server. (HTTP/... 2xx ...)
2006 * 1 : server_response = Buffer with parent proxy server response
2007 * 2 : response_len = Length of server_response
2009 * Returns : 1 => Connection created successfully
2010 * 0 => Connection wasn't created successfully
2012 *********************************************************************/
2013 extern int tunnel_established_successfully(const char *server_response,
2014 unsigned int response_len)
2016 unsigned int pos = 0;
2018 if (server_response == NULL)
2023 /* Tests if "HTTP/" string is at the begin of received response */
2024 if (strncmp(server_response, "HTTP/", 5) != 0)
2029 for (pos = 0; pos < response_len; pos++)
2031 if (server_response[pos] == ' ')
2038 * response_len -3 because of buffer end, response structure and 200 code.
2039 * There must be at least 3 chars after space.
2040 * End of buffer: ... 2xx'\0'
2043 if (pos >= (response_len - 3))
2048 /* Test HTTP status code */
2049 if (server_response[pos + 1] != '2')
2058 /*********************************************************************
2060 * Function : seed_rng
2062 * Description : Seeding the RNG for all SSL uses
2065 * 1 : csp = Current client state (buffers, headers, etc...)
2067 * Returns : -1 => RNG wasn't seed successfully
2068 * 0 => RNG is seeded successfully
2070 *********************************************************************/
2071 static int seed_rng(struct client_state *csp)
2074 char err_buf[ERROR_BUF_SIZE];
2076 memset(err_buf, 0, sizeof(err_buf));
2078 if (rng_seeded == 0)
2080 privoxy_mutex_lock(&rng_mutex);
2081 if (rng_seeded == 0)
2083 mbedtls_ctr_drbg_init(&ctr_drbg);
2084 mbedtls_entropy_init(&entropy);
2085 ret = mbedtls_ctr_drbg_seed(&ctr_drbg, mbedtls_entropy_func,
2089 mbedtls_strerror(ret, err_buf, sizeof(err_buf));
2090 log_error(LOG_LEVEL_ERROR,
2091 "mbedtls_ctr_drbg_seed failed: %s", err_buf);
2092 privoxy_mutex_unlock(&rng_mutex);
2097 privoxy_mutex_unlock(&rng_mutex);