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) 2018-2020 by Fabian Keil <fk@fabiankeil.de>
11 * This program is free software; you can redistribute it
12 * and/or modify it under the terms of the GNU General
13 * Public License as published by the Free Software
14 * Foundation; either version 2 of the License, or (at
15 * your option) any later version.
17 * This program is distributed in the hope that it will
18 * be useful, but WITHOUT ANY WARRANTY; without even the
19 * implied warranty of MERCHANTABILITY or FITNESS FOR A
20 * PARTICULAR PURPOSE. See the GNU General Public
21 * License for more details.
23 * The GNU General Public License should be included with
24 * this file. If not, you can view it at
25 * http://www.gnu.org/copyleft/gpl.html
26 * or write to the Free Software Foundation, Inc., 59
27 * Temple Place - Suite 330, Boston, MA 02111-1307, USA.
29 *********************************************************************/
34 #if !defined(MBEDTLS_CONFIG_FILE)
35 # include "mbedtls/config.h"
37 # include MBEDTLS_CONFIG_FILE
40 #include "mbedtls/md5.h"
41 #include "mbedtls/pem.h"
42 #include "mbedtls/base64.h"
43 #include "mbedtls/error.h"
54 * Macros for searching begin and end of certificates.
55 * Necessary to convert structure mbedtls_x509_crt to crt file.
57 #define PEM_BEGIN_CRT "-----BEGIN CERTIFICATE-----\n"
58 #define PEM_END_CRT "-----END CERTIFICATE-----\n"
63 #define ERROR_BUF_SIZE 1024 /* Size of buffer for error messages */
64 #define CERTIFICATE_BUF_SIZE 16384 /* Size of buffer to save certificate. Value 4096 is mbedtls library buffer size for certificate in DER form */
65 #define PRIVATE_KEY_BUF_SIZE 16000 /* Size of buffer to save private key. Value 16000 is taken from mbed TLS library examples. */
66 #define RSA_KEY_PUBLIC_EXPONENT 65537 /* Public exponent for RSA private key generating */
67 #define RSA_KEYSIZE 2048 /* Size of generated RSA keys */
68 #define GENERATED_CERT_VALID_FROM "20100101000000" /* Date and time, which will be set in generated certificates as parameter valid from */
69 #define GENERATED_CERT_VALID_TO "20401231235959" /* Date and time, which will be set in generated certificates as parameter valid to */
70 #define CERT_SIGNATURE_ALGORITHM MBEDTLS_MD_SHA256 /* The MD algorithm to use for the signature */
71 #define CERT_SERIAL_NUM_LENGTH 4 /* Bytes of hash to be used for creating serial number of certificate. Min=2 and max=16 */
72 #define INVALID_CERT_INFO_BUF_SIZE 2048 /* Size of buffer for message with information about reason of certificate invalidity. Data after the end of buffer will not be saved */
73 #define CERT_PARAM_COMMON_NAME "CN="
74 #define CERT_PARAM_ORGANIZATION ",O="
75 #define CERT_PARAM_ORG_UNIT ",OU="
76 #define CERT_PARAM_COUNTRY ",C=CZ"
77 #define KEY_FILE_TYPE ".pem"
78 #define CERT_FILE_TYPE ".crt"
79 #define CERT_SUBJECT_PASSWORD ""
80 #define CERT_INFO_PREFIX ""
83 * Properties of cert for generating
86 char *issuer_crt; /* filename of the issuer certificate */
87 char *subject_key; /* filename of the subject key file */
88 char *issuer_key; /* filename of the issuer key file */
89 const char *subject_pwd; /* password for the subject key file */
90 const char *issuer_pwd; /* password for the issuer key file */
91 char *output_file; /* where to store the constructed key file */
92 const char *subject_name; /* subject name for certificate */
93 char issuer_name[ISSUER_NAME_BUF_SIZE]; /* issuer name for certificate */
94 const char *not_before; /* validity period not before */
95 const char *not_after; /* validity period not after */
96 const char *serial; /* serial number string */
97 int is_ca; /* is a CA certificate */
98 int max_pathlen; /* maximum CA path length */
102 * Properties of key for generating
105 mbedtls_pk_type_t type; /* type of key to generate */
106 int rsa_keysize; /* length of key in bits */
107 char *key_file_path; /* filename of the key file */
110 static int generate_webpage_certificate(struct client_state *csp);
111 static char *make_certs_path(const char *conf_dir, const char *file_name, const char *suffix);
112 static int file_exists(const char *path);
113 static int host_to_hash(struct client_state *csp);
114 static int ssl_verify_callback(void *data, mbedtls_x509_crt *crt, int depth, uint32_t *flags);
115 static void free_certificate_chain(struct client_state *csp);
116 static unsigned int get_certificate_mutex_id(struct client_state *csp);
117 static unsigned long get_certificate_serial(struct client_state *csp);
118 static void free_client_ssl_structures(struct client_state *csp);
119 static void free_server_ssl_structures(struct client_state *csp);
120 static int seed_rng(struct client_state *csp);
122 /*********************************************************************
124 * Function : client_use_ssl
126 * Description : Tests if client in current client state structure
127 * should use SSL connection or standard connection.
130 * 1 : csp = Current client state (buffers, headers, etc...)
132 * Returns : If client should use TLS/SSL connection, 1 is returned.
133 * Otherwise 0 is returned.
135 *********************************************************************/
136 extern int client_use_ssl(const struct client_state *csp)
138 return csp->http->client_ssl;
142 /*********************************************************************
144 * Function : server_use_ssl
146 * Description : Tests if server in current client state structure
147 * should use SSL connection or standard connection.
150 * 1 : csp = Current client state (buffers, headers, etc...)
152 * Returns : If server should use TLS/SSL connection, 1 is returned.
153 * Otherwise 0 is returned.
155 *********************************************************************/
156 extern int server_use_ssl(const struct client_state *csp)
158 return csp->http->server_ssl;
162 /*********************************************************************
164 * Function : is_ssl_pending
166 * Description : Tests if there are some waiting data on ssl connection
169 * 1 : ssl = SSL context to test
171 * Returns : 0 => No data are pending
172 * >0 => Pending data length
174 *********************************************************************/
175 extern size_t is_ssl_pending(mbedtls_ssl_context *ssl)
182 return mbedtls_ssl_get_bytes_avail(ssl);
186 /*********************************************************************
188 * Function : ssl_send_data
190 * Description : Sends the content of buf (for n bytes) to given SSL
191 * connection context.
194 * 1 : ssl = SSL context to send data to
195 * 2 : buf = Pointer to data to be sent
196 * 3 : len = Length of data to be sent to the SSL context
198 * Returns : Length of sent data or negative value on error.
200 *********************************************************************/
201 extern int ssl_send_data(mbedtls_ssl_context *ssl, const unsigned char *buf, size_t len)
204 size_t max_fragment_size = 0; /* Maximal length of data in one SSL fragment*/
205 int send_len = 0; /* length of one data part to send */
206 int pos = 0; /* Position of unsent part in buffer */
213 /* Getting maximal length of data sent in one fragment */
214 max_fragment_size = mbedtls_ssl_get_max_frag_len(ssl);
217 * Whole buffer must be sent in many fragments, because each fragment
218 * has its maximal length.
222 /* Compute length of data, that can be send in next fragment */
223 if ((pos + (int)max_fragment_size) > len)
225 send_len = (int)len - pos;
229 send_len = (int)max_fragment_size;
232 log_error(LOG_LEVEL_WRITING, "TLS: %N", send_len, buf+pos);
235 * Sending one part of the buffer
237 while ((ret = mbedtls_ssl_write(ssl,
238 (const unsigned char *)(buf + pos),
239 (size_t)send_len)) < 0)
241 if (ret != MBEDTLS_ERR_SSL_WANT_READ &&
242 ret != MBEDTLS_ERR_SSL_WANT_WRITE)
244 char err_buf[ERROR_BUF_SIZE];
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 -1
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 if (ret == MBEDTLS_ERR_SSL_PEER_CLOSE_NOTIFY)
296 log_error(LOG_LEVEL_CONNECT,
297 "The peer notified us that the connection is going to be closed");
300 mbedtls_strerror(ret, err_buf, sizeof(err_buf));
301 log_error(LOG_LEVEL_ERROR,
302 "Receiving data over TLS/SSL failed: %s", err_buf);
307 log_error(LOG_LEVEL_RECEIVED, "TLS: %N", ret, buf);
313 /*********************************************************************
315 * Function : ssl_flush_socket
317 * Description : Send any pending "buffered" content with given
318 * SSL connection. Alternative to function flush_socket.
321 * 1 : ssl = SSL context to send buffer to
322 * 2 : iob = The I/O buffer to flush, usually csp->iob.
324 * Returns : On success, the number of bytes send are returned (zero
325 * indicates nothing was sent). On error, -1 is returned.
327 *********************************************************************/
328 extern long ssl_flush_socket(mbedtls_ssl_context *ssl, struct iob *iob)
330 /* Computing length of buffer part to send */
331 long len = iob->eod - iob->cur;
338 /* Sending data to given SSl context */
339 if (ssl_send_data(ssl, (const unsigned char *)iob->cur, (size_t)len) < 0)
343 iob->eod = iob->cur = iob->buf;
348 /*********************************************************************
350 * Function : ssl_debug_callback
352 * Description : Debug callback function for mbedtls library.
353 * Prints info into log file.
356 * 1 : ctx = File to save log in
357 * 2 : level = Debug level
358 * 3 : file = File calling debug message
359 * 4 : line = Line calling debug message
360 * 5 : str = Debug message
364 *********************************************************************/
365 static void ssl_debug_callback(void *ctx, int level, const char *file, int line, const char *str)
369 fprintf((FILE *)ctx, "%s:%04d: %s", file, line, str);
371 log_error(LOG_LEVEL_INFO, "SSL debug message: %s:%04d: %s", file, line, str);
376 /*********************************************************************
378 * Function : create_client_ssl_connection
380 * Description : Creates TLS/SSL secured connection with client
383 * 1 : csp = Current client state (buffers, headers, etc...)
385 * Returns : 0 on success, negative value if connection wasn't created
388 *********************************************************************/
389 extern int create_client_ssl_connection(struct client_state *csp)
391 /* Paths to certificates file and key file */
392 char *key_file = NULL;
393 char *ca_file = NULL;
394 char *cert_file = NULL;
396 char err_buf[ERROR_BUF_SIZE];
399 * Initializing mbedtls structures for TLS/SSL connection
401 mbedtls_net_init(&(csp->mbedtls_client_attr.socket_fd));
402 mbedtls_ssl_init(&(csp->mbedtls_client_attr.ssl));
403 mbedtls_ssl_config_init(&(csp->mbedtls_client_attr.conf));
404 mbedtls_x509_crt_init(&(csp->mbedtls_client_attr.server_cert));
405 mbedtls_pk_init(&(csp->mbedtls_client_attr.prim_key));
406 #if defined(MBEDTLS_SSL_CACHE_C)
407 mbedtls_ssl_cache_init(&(csp->mbedtls_client_attr.cache));
411 * Preparing hash of host for creating certificates
413 ret = host_to_hash(csp);
416 log_error(LOG_LEVEL_ERROR, "Generating hash of host failed: %d", ret);
422 * Preparing paths to certificates files and key file
424 ca_file = csp->config->ca_cert_file;
425 cert_file = make_certs_path(csp->config->certificate_directory,
426 (const char *)csp->http->hash_of_host_hex, CERT_FILE_TYPE);
427 key_file = make_certs_path(csp->config->certificate_directory,
428 (const char *)csp->http->hash_of_host_hex, KEY_FILE_TYPE);
430 if (cert_file == NULL || key_file == NULL)
437 * Generating certificate for requested host. Mutex to prevent
438 * certificate and key inconsistence must be locked.
440 unsigned int cert_mutex_id = get_certificate_mutex_id(csp);
441 privoxy_mutex_lock(&(certificates_mutexes[cert_mutex_id]));
443 ret = generate_webpage_certificate(csp);
446 log_error(LOG_LEVEL_ERROR,
447 "Generate_webpage_certificate failed: %d", ret);
448 privoxy_mutex_unlock(&(certificates_mutexes[cert_mutex_id]));
452 privoxy_mutex_unlock(&(certificates_mutexes[cert_mutex_id]));
465 * Loading CA file, webpage certificate and key files
467 ret = mbedtls_x509_crt_parse_file(&(csp->mbedtls_client_attr.server_cert),
471 mbedtls_strerror(ret, err_buf, sizeof(err_buf));
472 log_error(LOG_LEVEL_ERROR,
473 "Loading webpage certificate %s failed: %s", cert_file, err_buf);
478 ret = mbedtls_x509_crt_parse_file(&(csp->mbedtls_client_attr.server_cert),
482 mbedtls_strerror(ret, err_buf, sizeof(err_buf));
483 log_error(LOG_LEVEL_ERROR,
484 "Loading CA certificate %s failed: %s", ca_file, err_buf);
489 ret = mbedtls_pk_parse_keyfile(&(csp->mbedtls_client_attr.prim_key),
493 mbedtls_strerror(ret, err_buf, sizeof(err_buf));
494 log_error(LOG_LEVEL_ERROR,
495 "Loading and parsing webpage certificate private key %s failed: %s",
502 * Setting SSL parameters
504 ret = mbedtls_ssl_config_defaults(&(csp->mbedtls_client_attr.conf),
505 MBEDTLS_SSL_IS_SERVER, MBEDTLS_SSL_TRANSPORT_STREAM,
506 MBEDTLS_SSL_PRESET_DEFAULT);
509 mbedtls_strerror(ret, err_buf, sizeof(err_buf));
510 log_error(LOG_LEVEL_ERROR,
511 "mbedtls_ssl_config_defaults failed: %s", err_buf);
516 mbedtls_ssl_conf_rng(&(csp->mbedtls_client_attr.conf),
517 mbedtls_ctr_drbg_random, &ctr_drbg);
518 mbedtls_ssl_conf_dbg(&(csp->mbedtls_client_attr.conf),
519 ssl_debug_callback, stdout);
521 #if defined(MBEDTLS_SSL_CACHE_C)
522 mbedtls_ssl_conf_session_cache(&(csp->mbedtls_client_attr.conf),
523 &(csp->mbedtls_client_attr.cache), mbedtls_ssl_cache_get,
524 mbedtls_ssl_cache_set);
528 * Setting certificates
530 ret = mbedtls_ssl_conf_own_cert(&(csp->mbedtls_client_attr.conf),
531 &(csp->mbedtls_client_attr.server_cert),
532 &(csp->mbedtls_client_attr.prim_key));
535 mbedtls_strerror(ret, err_buf, sizeof(err_buf));
536 log_error(LOG_LEVEL_ERROR,
537 "mbedtls_ssl_conf_own_cert failed: %s", err_buf);
542 ret = mbedtls_ssl_setup(&(csp->mbedtls_client_attr.ssl),
543 &(csp->mbedtls_client_attr.conf));
546 mbedtls_strerror(ret, err_buf, sizeof(err_buf));
547 log_error(LOG_LEVEL_ERROR, "mbedtls_ssl_setup failed: %s", err_buf);
552 mbedtls_ssl_set_bio(&(csp->mbedtls_client_attr.ssl),
553 &(csp->mbedtls_client_attr.socket_fd), mbedtls_net_send,
554 mbedtls_net_recv, NULL);
555 mbedtls_ssl_session_reset(&(csp->mbedtls_client_attr.ssl));
558 * Setting socket fd in mbedtls_net_context structure. This structure
559 * can't be set by mbedtls functions, because we already have created
560 * a TCP connection when this function is called.
562 csp->mbedtls_client_attr.socket_fd.fd = csp->cfd;
565 * Handshake with client
567 log_error(LOG_LEVEL_CONNECT,
568 "Performing the TLS/SSL handshake with client. Hash of host: %s",
569 csp->http->hash_of_host_hex);
570 while ((ret = mbedtls_ssl_handshake(&(csp->mbedtls_client_attr.ssl))) != 0)
572 if (ret != MBEDTLS_ERR_SSL_WANT_READ &&
573 ret != MBEDTLS_ERR_SSL_WANT_WRITE)
575 mbedtls_strerror(ret, err_buf, sizeof(err_buf));
576 log_error(LOG_LEVEL_ERROR,
577 "medtls_ssl_handshake with client failed: %s", err_buf);
583 log_error(LOG_LEVEL_CONNECT, "Client successfully connected over TLS/SSL");
584 csp->ssl_with_client_is_opened = 1;
588 * Freeing allocated paths to files
593 /* Freeing structures if connection wasn't created successfully */
596 free_client_ssl_structures(csp);
602 /*********************************************************************
604 * Function : close_client_ssl_connection
606 * Description : Closes TLS/SSL connection with client. This function
607 * checks if this connection is already created.
610 * 1 : csp = Current client state (buffers, headers, etc...)
614 *********************************************************************/
615 extern void close_client_ssl_connection(struct client_state *csp)
619 if (csp->ssl_with_client_is_opened == 0)
625 * Notifying the peer that the connection is being closed.
628 ret = mbedtls_ssl_close_notify(&(csp->mbedtls_client_attr.ssl));
629 } while (ret == MBEDTLS_ERR_SSL_WANT_WRITE);
631 free_client_ssl_structures(csp);
632 csp->ssl_with_client_is_opened = 0;
636 /*********************************************************************
638 * Function : free_client_ssl_structures
640 * Description : Frees structures used for SSL communication with
644 * 1 : csp = Current client state (buffers, headers, etc...)
648 *********************************************************************/
649 static void free_client_ssl_structures(struct client_state *csp)
652 * We can't use function mbedtls_net_free, because this function
653 * inter alia close TCP connection on setted fd. Instead of this
654 * function, we change fd to -1, which is the same what does
655 * rest of mbedtls_net_free function.
657 csp->mbedtls_client_attr.socket_fd.fd = -1;
659 /* Freeing mbedtls structures */
660 mbedtls_x509_crt_free(&(csp->mbedtls_client_attr.server_cert));
661 mbedtls_pk_free(&(csp->mbedtls_client_attr.prim_key));
662 mbedtls_ssl_free(&(csp->mbedtls_client_attr.ssl));
663 mbedtls_ssl_config_free(&(csp->mbedtls_client_attr.conf));
664 #if defined(MBEDTLS_SSL_CACHE_C)
665 mbedtls_ssl_cache_free(&(csp->mbedtls_client_attr.cache));
670 /*********************************************************************
672 * Function : create_server_ssl_connection
674 * Description : Creates TLS/SSL secured connection with server.
677 * 1 : csp = Current client state (buffers, headers, etc...)
679 * Returns : 0 on success, negative value if connection wasn't created
682 *********************************************************************/
683 extern int create_server_ssl_connection(struct client_state *csp)
686 char err_buf[ERROR_BUF_SIZE];
687 char *trusted_cas_file = NULL;
688 int auth_mode = MBEDTLS_SSL_VERIFY_REQUIRED;
690 csp->server_cert_verification_result = SSL_CERT_NOT_VERIFIED;
691 csp->server_certs_chain.next = NULL;
693 /* Setting path to file with trusted CAs */
694 trusted_cas_file = csp->config->trusted_cas_file;
697 * Initializing mbedtls structures for TLS/SSL connection
699 mbedtls_net_init(&(csp->mbedtls_server_attr.socket_fd));
700 mbedtls_ssl_init(&(csp->mbedtls_server_attr.ssl));
701 mbedtls_ssl_config_init(&(csp->mbedtls_server_attr.conf));
702 mbedtls_x509_crt_init(&(csp->mbedtls_server_attr.ca_cert));
705 * Setting socket fd in mbedtls_net_context structure. This structure
706 * can't be set by mbedtls functions, because we already have created
707 * TCP connection when calling this function.
709 csp->mbedtls_server_attr.socket_fd.fd = csp->server_connection.sfd;
722 * Loading file with trusted CAs
724 ret = mbedtls_x509_crt_parse_file(&(csp->mbedtls_server_attr.ca_cert),
728 mbedtls_strerror(ret, err_buf, sizeof(err_buf));
729 log_error(LOG_LEVEL_ERROR, "Loading trusted CAs file %s failed: %s",
730 trusted_cas_file, err_buf);
736 * Set TLS/SSL options
738 ret = mbedtls_ssl_config_defaults(&(csp->mbedtls_server_attr.conf),
739 MBEDTLS_SSL_IS_CLIENT,
740 MBEDTLS_SSL_TRANSPORT_STREAM,
741 MBEDTLS_SSL_PRESET_DEFAULT);
744 mbedtls_strerror(ret, err_buf, sizeof(err_buf));
745 log_error(LOG_LEVEL_ERROR, "mbedtls_ssl_config_defaults failed: %s",
752 * Setting how strict should certificate verification be and other
753 * parameters for certificate verification
755 if (csp->dont_verify_certificate)
757 auth_mode = MBEDTLS_SSL_VERIFY_NONE;
760 mbedtls_ssl_conf_authmode(&(csp->mbedtls_server_attr.conf), auth_mode);
761 mbedtls_ssl_conf_ca_chain(&(csp->mbedtls_server_attr.conf),
762 &(csp->mbedtls_server_attr.ca_cert), NULL);
764 /* Setting callback function for certificates verification */
765 mbedtls_ssl_conf_verify(&(csp->mbedtls_server_attr.conf),
766 ssl_verify_callback, (void *)csp);
768 mbedtls_ssl_conf_rng(&(csp->mbedtls_server_attr.conf),
769 mbedtls_ctr_drbg_random, &ctr_drbg);
770 mbedtls_ssl_conf_dbg(&(csp->mbedtls_server_attr.conf),
771 ssl_debug_callback, stdout);
773 ret = mbedtls_ssl_setup(&(csp->mbedtls_server_attr.ssl),
774 &(csp->mbedtls_server_attr.conf));
777 mbedtls_strerror(ret, err_buf, sizeof(err_buf));
778 log_error(LOG_LEVEL_ERROR, "mbedtls_ssl_setup failed: %s", err_buf);
784 * Set the hostname to check against the received server certificate
786 ret = mbedtls_ssl_set_hostname(&(csp->mbedtls_server_attr.ssl),
790 mbedtls_strerror(ret, err_buf, sizeof(err_buf));
791 log_error(LOG_LEVEL_ERROR, "mbedtls_ssl_set_hostname failed: %s",
797 mbedtls_ssl_set_bio(&(csp->mbedtls_server_attr.ssl),
798 &(csp->mbedtls_server_attr.socket_fd), mbedtls_net_send,
799 mbedtls_net_recv, NULL);
802 * Handshake with server
804 log_error(LOG_LEVEL_CONNECT,
805 "Performing the TLS/SSL handshake with the server");
807 while ((ret = mbedtls_ssl_handshake(&(csp->mbedtls_server_attr.ssl))) != 0)
809 if (ret != MBEDTLS_ERR_SSL_WANT_READ
810 && ret != MBEDTLS_ERR_SSL_WANT_WRITE)
812 mbedtls_strerror(ret, err_buf, sizeof(err_buf));
814 if (ret == MBEDTLS_ERR_X509_CERT_VERIFY_FAILED)
816 char reason[INVALID_CERT_INFO_BUF_SIZE];
818 csp->server_cert_verification_result =
819 mbedtls_ssl_get_verify_result(&(csp->mbedtls_server_attr.ssl));
820 mbedtls_x509_crt_verify_info(reason, sizeof(reason), "",
821 csp->server_cert_verification_result);
823 /* Log the reason without the trailing new line */
824 log_error(LOG_LEVEL_ERROR,
825 "The X509 certificate verification failed: %N",
826 strlen(reason)-1, reason);
831 log_error(LOG_LEVEL_ERROR,
832 "mbedtls_ssl_handshake with server failed: %s", err_buf);
839 log_error(LOG_LEVEL_CONNECT, "Server successfully connected over TLS/SSL");
842 * Server certificate chain is valid, so we can clean
843 * chain, because we will not send it to client.
845 free_certificate_chain(csp);
847 csp->ssl_with_server_is_opened = 1;
848 csp->server_cert_verification_result =
849 mbedtls_ssl_get_verify_result(&(csp->mbedtls_server_attr.ssl));
852 /* Freeing structures if connection wasn't created successfully */
855 free_server_ssl_structures(csp);
862 /*********************************************************************
864 * Function : close_server_ssl_connection
866 * Description : Closes TLS/SSL connection with server. This function
867 * checks if this connection is already opened.
870 * 1 : csp = Current client state (buffers, headers, etc...)
874 *********************************************************************/
875 static void close_server_ssl_connection(struct client_state *csp)
879 if (csp->ssl_with_server_is_opened == 0)
885 * Notifying the peer that the connection is being closed.
888 ret = mbedtls_ssl_close_notify(&(csp->mbedtls_server_attr.ssl));
889 } while (ret == MBEDTLS_ERR_SSL_WANT_WRITE);
891 free_server_ssl_structures(csp);
892 csp->ssl_with_server_is_opened = 0;
896 /*********************************************************************
898 * Function : free_server_ssl_structures
900 * Description : Frees structures used for SSL communication with server
903 * 1 : csp = Current client state (buffers, headers, etc...)
907 *********************************************************************/
908 static void free_server_ssl_structures(struct client_state *csp)
911 * We can't use function mbedtls_net_free, because this function
912 * inter alia close TCP connection on setted fd. Instead of this
913 * function, we change fd to -1, which is the same what does
914 * rest of mbedtls_net_free function.
916 csp->mbedtls_server_attr.socket_fd.fd = -1;
918 mbedtls_x509_crt_free(&(csp->mbedtls_server_attr.ca_cert));
919 mbedtls_ssl_free(&(csp->mbedtls_server_attr.ssl));
920 mbedtls_ssl_config_free(&(csp->mbedtls_server_attr.conf));
924 /*********************************************************************
926 * Function : close_client_and_server_ssl_connections
928 * Description : Checks if client or server should use secured
929 * connection over SSL and if so, closes all of them.
932 * 1 : csp = Current client state (buffers, headers, etc...)
936 *********************************************************************/
937 extern void close_client_and_server_ssl_connections(struct client_state *csp)
939 if (client_use_ssl(csp) == 1)
941 close_client_ssl_connection(csp);
943 if (server_use_ssl(csp) == 1)
945 close_server_ssl_connection(csp);
949 /*====================== Certificates ======================*/
951 /*********************************************************************
953 * Function : write_certificate
955 * Description : Writes certificate into file.
958 * 1 : crt = certificate to write into file
959 * 2 : output_file = path to save certificate file
960 * 3 : f_rng = mbedtls_ctr_drbg_random
961 * 4 : p_rng = mbedtls_ctr_drbg_context
963 * Returns : Length of written certificate on success or negative value
966 *********************************************************************/
967 static int write_certificate(mbedtls_x509write_cert *crt, const char *output_file,
968 int(*f_rng)(void *, unsigned char *, size_t), void *p_rng)
972 unsigned char cert_buf[CERTIFICATE_BUF_SIZE + 1]; /* Buffer for certificate in PEM format + terminating NULL */
974 char err_buf[ERROR_BUF_SIZE];
976 memset(cert_buf, 0, sizeof(cert_buf));
979 * Writing certificate into PEM string. If buffer is too small, function
980 * returns specific error and no buffer overflow can happen.
982 if ((ret = mbedtls_x509write_crt_pem(crt, cert_buf,
983 sizeof(cert_buf) - 1, f_rng, p_rng)) != 0)
985 mbedtls_strerror(ret, err_buf, sizeof(err_buf));
986 log_error(LOG_LEVEL_ERROR,
987 "Writing certificate into buffer failed: %s", err_buf);
991 len = strlen((char *)cert_buf);
994 * Saving certificate into file
996 if ((f = fopen(output_file, "w")) == NULL)
998 log_error(LOG_LEVEL_ERROR, "Opening file %s to save certificate failed",
1003 if (fwrite(cert_buf, 1, len, f) != len)
1005 log_error(LOG_LEVEL_ERROR,
1006 "Writing certificate into file %s failed", output_file);
1017 /*********************************************************************
1019 * Function : write_private_key
1021 * Description : Writes private key into file and copies saved
1022 * content into given pointer to string. If function
1023 * returns 0 for success, this copy must be freed by
1027 * 1 : key = key to write into file
1028 * 2 : ret_buf = pointer to string with created key file content
1029 * 3 : key_file_path = path where to save key file
1031 * Returns : Length of written private key on success or negative value
1034 *********************************************************************/
1035 static int write_private_key(mbedtls_pk_context *key, unsigned char **ret_buf,
1036 const char *key_file_path)
1038 size_t len = 0; /* Length of created key */
1039 FILE *f = NULL; /* File to save certificate */
1041 char err_buf[ERROR_BUF_SIZE];
1043 /* Initializing buffer for key file content */
1044 *ret_buf = zalloc_or_die(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 : csp = Current client state (buffers, headers, etc...)
1107 * 2 : key_buf = buffer to save new generated key
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(struct client_state *csp, unsigned char **key_buf)
1116 mbedtls_pk_context key;
1117 key_options key_opt;
1119 char err_buf[ERROR_BUF_SIZE];
1121 key_opt.key_file_path = NULL;
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 already exists.
1221 * >0 => Length of created certificate.
1223 *********************************************************************/
1224 static 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 /* Paths to keys and certificates needed to create certificate */
1240 cert_opt.issuer_key = NULL;
1241 cert_opt.subject_key = NULL;
1242 cert_opt.issuer_crt = NULL;
1243 cert_opt.output_file = NULL;
1246 * Create key for requested host
1248 int subject_key_len = generate_key(csp, &key_buf);
1249 if (subject_key_len < 0)
1251 log_error(LOG_LEVEL_ERROR, "Key generating failed");
1256 * Initializing structures for certificate generating
1258 mbedtls_x509write_crt_init(&cert);
1259 mbedtls_x509write_crt_set_md_alg(&cert, CERT_SIGNATURE_ALGORITHM);
1260 mbedtls_pk_init(&loaded_issuer_key);
1261 mbedtls_pk_init(&loaded_subject_key);
1262 mbedtls_mpi_init(&serial);
1263 mbedtls_x509_crt_init(&issuer_cert);
1266 * Presetting parameters for certificate. We must compute total length
1269 size_t cert_params_len = strlen(CERT_PARAM_COMMON_NAME) +
1270 strlen(CERT_PARAM_ORGANIZATION) + strlen(CERT_PARAM_COUNTRY) +
1271 strlen(CERT_PARAM_ORG_UNIT) +
1272 3 * strlen(csp->http->host) + 1;
1273 char cert_params[cert_params_len];
1274 memset(cert_params, 0, cert_params_len);
1277 * Converting unsigned long serial number to char * serial number.
1278 * We must compute length of serial number in string + terminating null.
1280 unsigned long certificate_serial = get_certificate_serial(csp);
1281 int serial_num_size = snprintf(NULL, 0, "%lu", certificate_serial) + 1;
1282 if (serial_num_size <= 0)
1284 serial_num_size = 1;
1287 char serial_num_text[serial_num_size]; /* Buffer for serial number */
1288 ret = snprintf(serial_num_text, (size_t)serial_num_size, "%lu", certificate_serial);
1289 if (ret < 0 || ret >= serial_num_size)
1291 log_error(LOG_LEVEL_ERROR,
1292 "Converting certificate serial number into string failed");
1298 * Preparing parameters for certificate
1300 strlcpy(cert_params, CERT_PARAM_COMMON_NAME, cert_params_len);
1301 strlcat(cert_params, csp->http->host, cert_params_len);
1302 strlcat(cert_params, CERT_PARAM_ORGANIZATION, cert_params_len);
1303 strlcat(cert_params, csp->http->host, cert_params_len);
1304 strlcat(cert_params, CERT_PARAM_ORG_UNIT, cert_params_len);
1305 strlcat(cert_params, csp->http->host, cert_params_len);
1306 strlcat(cert_params, CERT_PARAM_COUNTRY, cert_params_len);
1308 cert_opt.issuer_crt = csp->config->ca_cert_file;
1309 cert_opt.issuer_key = csp->config->ca_key_file;
1310 cert_opt.subject_key = make_certs_path(csp->config->certificate_directory,
1311 (const char *)csp->http->hash_of_host_hex, KEY_FILE_TYPE);
1312 cert_opt.output_file = make_certs_path(csp->config->certificate_directory,
1313 (const char *)csp->http->hash_of_host_hex, CERT_FILE_TYPE);
1315 if (cert_opt.subject_key == NULL || cert_opt.output_file == NULL)
1321 cert_opt.subject_pwd = CERT_SUBJECT_PASSWORD;
1322 cert_opt.issuer_pwd = csp->config->ca_password;
1323 cert_opt.subject_name = cert_params;
1324 cert_opt.not_before = GENERATED_CERT_VALID_FROM;
1325 cert_opt.not_after = GENERATED_CERT_VALID_TO;
1326 cert_opt.serial = serial_num_text;
1328 cert_opt.max_pathlen = -1;
1331 * Test if certificate exists and private key was already created
1333 if (file_exists(cert_opt.output_file) == 1 && subject_key_len == 0)
1342 ret = seed_rng(csp);
1350 * Parse serial to MPI
1352 ret = mbedtls_mpi_read_string(&serial, 10, cert_opt.serial);
1355 mbedtls_strerror(ret, err_buf, sizeof(err_buf));
1356 log_error(LOG_LEVEL_ERROR,
1357 "mbedtls_mpi_read_string failed: %s", err_buf);
1363 * Loading certificates
1365 ret = mbedtls_x509_crt_parse_file(&issuer_cert, cert_opt.issuer_crt);
1368 mbedtls_strerror(ret, err_buf, sizeof(err_buf));
1369 log_error(LOG_LEVEL_ERROR, "Loading issuer certificate %s failed: %s",
1370 cert_opt.issuer_crt, err_buf);
1375 ret = mbedtls_x509_dn_gets(cert_opt.issuer_name,
1376 sizeof(cert_opt.issuer_name), &issuer_cert.subject);
1379 mbedtls_strerror(ret, err_buf, sizeof(err_buf));
1380 log_error(LOG_LEVEL_ERROR, "mbedtls_x509_dn_gets failed: %s", err_buf);
1386 * Loading keys from file or from buffer
1388 if (key_buf != NULL && subject_key_len > 0)
1390 /* Key was created in this function and is stored in buffer */
1391 ret = mbedtls_pk_parse_key(&loaded_subject_key, key_buf,
1392 (size_t)(subject_key_len + 1), (unsigned const char *)
1393 cert_opt.subject_pwd, strlen(cert_opt.subject_pwd));
1397 /* Key wasn't created in this function, because it already existed */
1398 ret = mbedtls_pk_parse_keyfile(&loaded_subject_key,
1399 cert_opt.subject_key, cert_opt.subject_pwd);
1404 mbedtls_strerror(ret, err_buf, sizeof(err_buf));
1405 log_error(LOG_LEVEL_ERROR, "Parsing subject key %s failed: %s",
1406 cert_opt.subject_key, err_buf);
1411 ret = mbedtls_pk_parse_keyfile(&loaded_issuer_key, cert_opt.issuer_key,
1412 cert_opt.issuer_pwd);
1415 mbedtls_strerror(ret, err_buf, sizeof(err_buf));
1416 log_error(LOG_LEVEL_ERROR,
1417 "Parsing issuer key %s failed: %s", cert_opt.issuer_key, err_buf);
1423 * Check if key and issuer certificate match
1425 if (!mbedtls_pk_can_do(&issuer_cert.pk, MBEDTLS_PK_RSA) ||
1426 mbedtls_mpi_cmp_mpi(&mbedtls_pk_rsa(issuer_cert.pk)->N,
1427 &mbedtls_pk_rsa(*issuer_key)->N) != 0 ||
1428 mbedtls_mpi_cmp_mpi(&mbedtls_pk_rsa(issuer_cert.pk)->E,
1429 &mbedtls_pk_rsa(*issuer_key)->E) != 0)
1431 log_error(LOG_LEVEL_ERROR,
1432 "Issuer key doesn't match issuer certificate");
1437 mbedtls_x509write_crt_set_subject_key(&cert, subject_key);
1438 mbedtls_x509write_crt_set_issuer_key(&cert, issuer_key);
1441 * Setting parameters of signed certificate
1443 ret = mbedtls_x509write_crt_set_subject_name(&cert, cert_opt.subject_name);
1446 mbedtls_strerror(ret, err_buf, sizeof(err_buf));
1447 log_error(LOG_LEVEL_ERROR,
1448 "Setting subject name in signed certificate failed: %s", err_buf);
1453 ret = mbedtls_x509write_crt_set_issuer_name(&cert, cert_opt.issuer_name);
1456 mbedtls_strerror(ret, err_buf, sizeof(err_buf));
1457 log_error(LOG_LEVEL_ERROR,
1458 "Setting issuer name in signed certificate failed: %s", err_buf);
1463 ret = mbedtls_x509write_crt_set_serial(&cert, &serial);
1466 mbedtls_strerror(ret, err_buf, sizeof(err_buf));
1467 log_error(LOG_LEVEL_ERROR,
1468 "Setting serial number in signed certificate failed: %s", err_buf);
1473 ret = mbedtls_x509write_crt_set_validity(&cert, cert_opt.not_before,
1474 cert_opt.not_after);
1477 mbedtls_strerror(ret, err_buf, sizeof(err_buf));
1478 log_error(LOG_LEVEL_ERROR,
1479 "Setting validity in signed certificate failed: %s", err_buf);
1485 * Setting the basicConstraints extension for certificate
1487 ret = mbedtls_x509write_crt_set_basic_constraints(&cert, cert_opt.is_ca,
1488 cert_opt.max_pathlen);
1491 mbedtls_strerror(ret, err_buf, sizeof(err_buf));
1492 log_error(LOG_LEVEL_ERROR, "Setting the basicConstraints extension "
1493 "in signed certificate failed: %s", err_buf);
1498 #if defined(MBEDTLS_SHA1_C)
1499 /* Setting the subjectKeyIdentifier extension for certificate */
1500 ret = mbedtls_x509write_crt_set_subject_key_identifier(&cert);
1503 mbedtls_strerror(ret, err_buf, sizeof(err_buf));
1504 log_error(LOG_LEVEL_ERROR, "mbedtls_x509write_crt_set_subject_key_"
1505 "identifier failed: %s", err_buf);
1510 /* Setting the authorityKeyIdentifier extension for certificate */
1511 ret = mbedtls_x509write_crt_set_authority_key_identifier(&cert);
1514 mbedtls_strerror(ret, err_buf, sizeof(err_buf));
1515 log_error(LOG_LEVEL_ERROR, "mbedtls_x509write_crt_set_authority_key_"
1516 "identifier failed: %s", err_buf);
1520 #endif /* MBEDTLS_SHA1_C */
1523 * Writing certificate into file
1525 ret = write_certificate(&cert, cert_opt.output_file,
1526 mbedtls_ctr_drbg_random, &ctr_drbg);
1529 log_error(LOG_LEVEL_ERROR, "Writing certificate into file failed");
1535 * Freeing used structures
1537 mbedtls_x509write_crt_free(&cert);
1538 mbedtls_pk_free(&loaded_subject_key);
1539 mbedtls_pk_free(&loaded_issuer_key);
1540 mbedtls_mpi_free(&serial);
1541 mbedtls_x509_crt_free(&issuer_cert);
1543 freez(cert_opt.subject_key);
1544 freez(cert_opt.output_file);
1551 /*********************************************************************
1553 * Function : make_certs_path
1555 * Description : Creates path to file from three pieces. This function
1556 * takes parameters and puts them in one new mallocated
1557 * char * in correct order. Returned variable must be freed
1558 * by caller. This function is mainly used for creating
1559 * paths of certificates and keys files.
1562 * 1 : conf_dir = Name/path of directory where is the file.
1563 * '.' can be used for current directory.
1564 * 2 : file_name = Name of file in conf_dir without suffix.
1565 * 3 : suffix = Suffix of given file_name.
1567 * Returns : path => Path was built up successfully
1568 * NULL => Path can't be built up
1570 *********************************************************************/
1571 static char *make_certs_path(const char *conf_dir, const char *file_name,
1574 /* Test if all given parameters are valid */
1575 if (conf_dir == NULL || *conf_dir == '\0' || file_name == NULL ||
1576 *file_name == '\0' || suffix == NULL || *suffix == '\0')
1578 log_error(LOG_LEVEL_ERROR,
1579 "make_certs_path failed: bad input parameters");
1584 size_t path_size = strlen(conf_dir)
1585 + strlen(file_name) + strlen(suffix) + 2;
1587 /* Setting delimiter and editing path length */
1588 #if defined(_WIN32) || defined(__OS2__)
1589 char delim[] = "\\";
1591 #else /* ifndef _WIN32 || __OS2__ */
1593 #endif /* ifndef _WIN32 || __OS2__ */
1596 * Building up path from many parts
1599 if (*conf_dir != '/' && basedir && *basedir)
1602 * Replacing conf_dir with basedir. This new variable contains
1603 * absolute path to cwd.
1605 path_size += strlen(basedir) + 2;
1606 path = zalloc_or_die(path_size);
1608 strlcpy(path, basedir, path_size);
1609 strlcat(path, delim, path_size);
1610 strlcat(path, conf_dir, path_size);
1611 strlcat(path, delim, path_size);
1612 strlcat(path, file_name, path_size);
1613 strlcat(path, suffix, path_size);
1616 #endif /* defined unix */
1618 path = zalloc_or_die(path_size);
1620 strlcpy(path, conf_dir, path_size);
1621 strlcat(path, delim, path_size);
1622 strlcat(path, file_name, path_size);
1623 strlcat(path, suffix, path_size);
1630 /*********************************************************************
1632 * Function : get_certificate_mutex_id
1634 * Description : Computes mutex id from host name hash. This hash must
1635 * be already saved in csp structure
1638 * 1 : csp = Current client state (buffers, headers, etc...)
1640 * Returns : Mutex id for given host name
1642 *********************************************************************/
1643 static unsigned int get_certificate_mutex_id(struct client_state *csp) {
1644 #ifdef LIMIT_MUTEX_NUMBER
1645 return (unsigned int)(csp->http->hash_of_host[0] % 32);
1647 return (unsigned int)(csp->http->hash_of_host[1]
1648 + 256 * (int)csp->http->hash_of_host[0]);
1649 #endif /* LIMIT_MUTEX_NUMBER */
1653 /*********************************************************************
1655 * Function : get_certificate_serial
1657 * Description : Computes serial number for new certificate from host
1658 * name hash. This hash must be already saved in csp
1662 * 1 : csp = Current client state (buffers, headers, etc...)
1664 * Returns : Serial number for new certificate
1666 *********************************************************************/
1667 static unsigned long get_certificate_serial(struct client_state *csp)
1669 unsigned long exp = 1;
1670 unsigned long serial = 0;
1672 int i = CERT_SERIAL_NUM_LENGTH;
1673 /* Length of hash is 16 bytes, we must avoid to read next chars */
1685 serial += exp * (unsigned)csp->http->hash_of_host[i];
1692 /*********************************************************************
1694 * Function : ssl_send_certificate_error
1696 * Description : Sends info about invalid server certificate to client.
1697 * Sent message is including all trusted chain certificates,
1698 * that can be downloaded in web browser.
1701 * 1 : csp = Current client state (buffers, headers, etc...)
1705 *********************************************************************/
1706 extern void ssl_send_certificate_error(struct client_state *csp)
1708 size_t message_len = 0;
1710 struct certs_chain *cert = NULL;
1712 /* Header of message with certificate informations */
1713 const char message_begin[] =
1714 "HTTP/1.1 200 OK\r\n"
1715 "Content-Type: text/html\r\n"
1716 "Connection: close\r\n\r\n"
1717 "<html><body><h1>Invalid server certificate</h1><p>Reason: ";
1718 const char message_end[] = "</body></html>\r\n\r\n";
1719 char reason[INVALID_CERT_INFO_BUF_SIZE];
1720 memset(reason, 0, sizeof(reason));
1722 /* Get verification message from verification return code */
1723 mbedtls_x509_crt_verify_info(reason, sizeof(reason), " ",
1724 csp->server_cert_verification_result);
1727 * Computing total length of message with all certificates inside
1729 message_len = strlen(message_begin) + strlen(message_end)
1730 + strlen(reason) + strlen("</p>") + 1;
1732 cert = &(csp->server_certs_chain);
1733 while (cert->next != NULL)
1735 size_t base64_len = 4 * ((strlen(cert->file_buf) + 2) / 3) + 1;
1737 message_len += strlen(cert->text_buf) + strlen("<pre></pre>\n")
1738 + base64_len + strlen("<a href=\"data:application"
1739 "/x-x509-ca-cert;base64,\">Download certificate</a>");
1744 * Joining all blocks in one long message
1746 char message[message_len];
1747 memset(message, 0, message_len);
1749 strlcpy(message, message_begin, message_len);
1750 strlcat(message, reason , message_len);
1751 strlcat(message, "</p>" , message_len);
1753 cert = &(csp->server_certs_chain);
1754 while (cert->next != NULL)
1757 size_t base64_len = 4 * ((strlen(cert->file_buf) + 2) / 3) + 1; /* +1 for terminating null*/
1758 char base64_buf[base64_len];
1759 memset(base64_buf, 0, base64_len);
1761 /* Encoding certificate into base64 code */
1762 ret = mbedtls_base64_encode((unsigned char*)base64_buf,
1763 base64_len, &olen, (const unsigned char*)cert->file_buf,
1764 strlen(cert->file_buf));
1767 log_error(LOG_LEVEL_ERROR,
1768 "Encoding to base64 failed, buffer is to small");
1771 strlcat(message, "<pre>", message_len);
1772 strlcat(message, cert->text_buf, message_len);
1773 strlcat(message, "</pre>\n", message_len);
1777 strlcat(message, "<a href=\"data:application/x-x509-ca-cert;base64,",
1779 strlcat(message, base64_buf, message_len);
1780 strlcat(message, "\">Download certificate</a>", message_len);
1785 strlcat(message, message_end, message_len);
1788 * Sending final message to client
1790 ssl_send_data(&(csp->mbedtls_client_attr.ssl),
1791 (const unsigned char *)message, strlen(message));
1793 * Waiting before closing connection. Some browsers don't show received
1794 * message if there isn't this delay.
1798 free_certificate_chain(csp);
1802 /*********************************************************************
1804 * Function : ssl_verify_callback
1806 * Description : This is a callback function for certificate verification.
1807 * It's called for all certificates in server certificate
1808 * trusted chain and it's preparing information about this
1809 * certificates. Prepared informations can be used to inform
1810 * user about invalid certificates.
1813 * 1 : csp_void = Current client state (buffers, headers, etc...)
1814 * 2 : crt = certificate from trusted chain
1815 * 3 : depth = depth in trusted chain
1816 * 4 : flags = certificate flags
1818 * Returns : 0 on success and negative value on error
1820 *********************************************************************/
1821 static int ssl_verify_callback(void *csp_void, mbedtls_x509_crt *crt,
1822 int depth, uint32_t *flags)
1824 struct client_state *csp = (struct client_state *)csp_void;
1825 struct certs_chain *last = &(csp->server_certs_chain);
1830 * Searching for last item in certificates linked list
1832 while (last->next != NULL)
1838 * Preparing next item in linked list for next certificate
1840 last->next = malloc_or_die(sizeof(struct certs_chain));
1841 last->next->next = NULL;
1842 memset(last->next->text_buf, 0, sizeof(last->next->text_buf));
1843 memset(last->next->file_buf, 0, sizeof(last->next->file_buf));
1846 * Saving certificate file into buffer
1848 if ((ret = mbedtls_pem_write_buffer(PEM_BEGIN_CRT, PEM_END_CRT,
1849 crt->raw.p, crt->raw.len, (unsigned char *)last->file_buf,
1850 sizeof(last->file_buf)-1, &olen)) != 0)
1856 * Saving certificate information into buffer
1858 mbedtls_x509_crt_info(last->text_buf, sizeof(last->text_buf) - 1,
1859 CERT_INFO_PREFIX, crt);
1865 /*********************************************************************
1867 * Function : free_certificate_chain
1869 * Description : Frees certificates linked list. This linked list is
1870 * used to save informations about certificates in
1874 * 1 : csp = Current client state (buffers, headers, etc...)
1878 *********************************************************************/
1879 static void free_certificate_chain(struct client_state *csp)
1881 struct certs_chain *cert = csp->server_certs_chain.next;
1883 /* Cleaning buffers */
1884 memset(csp->server_certs_chain.text_buf, 0,
1885 sizeof(csp->server_certs_chain.text_buf));
1886 memset(csp->server_certs_chain.file_buf, 0,
1887 sizeof(csp->server_certs_chain.file_buf));
1888 csp->server_certs_chain.next = NULL;
1890 /* Freeing memory in whole linked list */
1895 struct certs_chain *cert_for_free = cert;
1897 freez(cert_for_free);
1898 } while (cert != NULL);
1903 /*********************************************************************
1905 * Function : file_exists
1907 * Description : Tests if file exists and is readable.
1910 * 1 : path = Path to tested file.
1912 * Returns : 1 => File exists and is readable.
1913 * 0 => File doesn't exist or is not readable.
1915 *********************************************************************/
1916 static int file_exists(const char *path)
1919 if ((f = fopen(path, "r")) != NULL)
1929 /*********************************************************************
1931 * Function : host_to_hash
1933 * Description : Creates MD5 hash from host name. Host name is loaded
1934 * from structure csp and saved again into it.
1937 * 1 : csp = Current client state (buffers, headers, etc...)
1939 * Returns : 1 => Error while creating hash
1940 * 0 => Hash created successfully
1942 *********************************************************************/
1943 static int host_to_hash(struct client_state *csp)
1947 #if !defined(MBEDTLS_MD5_C)
1948 log_error(LOG_LEVEL_ERROR, "MBEDTLS_MD5_C is not defined. Can't create"
1949 "MD5 hash for certificate and key name.");
1952 memset(csp->http->hash_of_host, 0, sizeof(csp->http->hash_of_host));
1953 mbedtls_md5((unsigned char *)csp->http->host, strlen(csp->http->host),
1954 csp->http->hash_of_host);
1956 /* Converting hash into string with hex */
1960 if ((ret = sprintf((char *)csp->http->hash_of_host_hex + 2 * i, "%02x",
1961 csp->http->hash_of_host[i])) < 0)
1963 log_error(LOG_LEVEL_ERROR, "Sprintf return value: %d", ret);
1969 #endif /* MBEDTLS_MD5_C */
1973 /*********************************************************************
1975 * Function : tunnel_established_successfully
1977 * Description : Check if parent proxy server response contains
1978 * informations about successfully created connection with
1979 * destination server. (HTTP/... 2xx ...)
1982 * 1 : server_response = Buffer with parent proxy server response
1983 * 2 : response_len = Length of server_response
1985 * Returns : 1 => Connection created successfully
1986 * 0 => Connection wasn't created successfully
1988 *********************************************************************/
1989 extern int tunnel_established_successfully(const char *server_response,
1990 unsigned int response_len)
1992 unsigned int pos = 0;
1994 if (server_response == NULL)
1999 /* Tests if "HTTP/" string is at the begin of received response */
2000 if (strncmp(server_response, "HTTP/", 5) != 0)
2005 for (pos = 0; pos < response_len; pos++)
2007 if (server_response[pos] == ' ')
2014 * response_len -3 because of buffer end, response structure and 200 code.
2015 * There must be at least 3 chars after space.
2016 * End of buffer: ... 2xx'\0'
2019 if (pos >= (response_len - 3))
2024 /* Test HTTP status code */
2025 if (server_response[pos + 1] != '2')
2034 /*********************************************************************
2036 * Function : seed_rng
2038 * Description : Seeding the RNG for all SSL uses
2041 * 1 : csp = Current client state (buffers, headers, etc...)
2043 * Returns : -1 => RNG wasn't seed successfully
2044 * 0 => RNG is seeded successfully
2046 *********************************************************************/
2047 static int seed_rng(struct client_state *csp)
2050 char err_buf[ERROR_BUF_SIZE];
2052 if (rng_seeded == 0)
2054 privoxy_mutex_lock(&rng_mutex);
2055 if (rng_seeded == 0)
2057 mbedtls_ctr_drbg_init(&ctr_drbg);
2058 mbedtls_entropy_init(&entropy);
2059 ret = mbedtls_ctr_drbg_seed(&ctr_drbg, mbedtls_entropy_func,
2063 mbedtls_strerror(ret, err_buf, sizeof(err_buf));
2064 log_error(LOG_LEVEL_ERROR,
2065 "mbedtls_ctr_drbg_seed failed: %s", err_buf);
2066 privoxy_mutex_unlock(&rng_mutex);
2071 privoxy_mutex_unlock(&rng_mutex);