/********************************************************************* * * File : $Source: /cvsroot/ijbswa/current/ssl_common.c,v $ * * Purpose : File with TLS/SSL extension. Contains methods for * creating, using and closing TLS/SSL connections that do * not depend on particular TLS/SSL library. * * Copyright : Written by and Copyright (c) 2017 Vaclav Svec. FIT CVUT. * Copyright (C) 2018-2020 by Fabian Keil * * This program is free software; you can redistribute it * and/or modify it under the terms of the GNU General * Public License as published by the Free Software * Foundation; either version 2 of the License, or (at * your option) any later version. * * This program is distributed in the hope that it will * be useful, but WITHOUT ANY WARRANTY; without even the * implied warranty of MERCHANTABILITY or FITNESS FOR A * PARTICULAR PURPOSE. See the GNU General Public * License for more details. * * The GNU General Public License should be included with * this file. If not, you can view it at * http://www.gnu.org/copyleft/gpl.html * or write to the Free Software Foundation, Inc., 59 * Temple Place - Suite 330, Boston, MA 02111-1307, USA. * *********************************************************************/ #include #include #include "config.h" #include "project.h" #include "miscutil.h" #include "errlog.h" #include "ssl.h" #include "ssl_common.h" /* * Macros for ssl_common.c */ #define CERT_SERIAL_NUM_LENGTH 4 /* Bytes of hash to be used for creating serial number of certificate. Min=2 and max=16 */ /********************************************************************* * * Function : client_use_ssl * * Description : Tests if client in current client state structure * should use SSL connection or standard connection. * * Parameters : * 1 : csp = Current client state (buffers, headers, etc...) * * Returns : If client should use TLS/SSL connection, 1 is returned. * Otherwise 0 is returned. * *********************************************************************/ extern int client_use_ssl(const struct client_state *csp) { return csp->http->client_ssl; } /********************************************************************* * * Function : server_use_ssl * * Description : Tests if server in current client state structure * should use SSL connection or standard connection. * * Parameters : * 1 : csp = Current client state (buffers, headers, etc...) * * Returns : If server should use TLS/SSL connection, 1 is returned. * Otherwise 0 is returned. * *********************************************************************/ extern int server_use_ssl(const struct client_state *csp) { return csp->http->server_ssl; } /********************************************************************* * * Function : ssl_send_data_delayed * * Description : Sends the contents of buf (for n bytes) to given SSL * connection, optionally delaying the operation. * * Parameters : * 1 : ssl_attr = SSL context to send data to * 2 : buf = Pointer to data to be sent * 3 : len = Length of data to be sent to the SSL context * 4 : delay = Delay in milliseconds. * * Returns : 0 on success (entire buffer sent). * nonzero on error. * *********************************************************************/ extern int ssl_send_data_delayed(struct ssl_attr* ssl_attr, const unsigned char *buf, size_t len, unsigned int delay) { size_t i = 0; if (delay == 0) { if (ssl_send_data(ssl_attr, buf, len) < 0) { return -1; } else { return 0; } } while (i < len) { size_t write_length; enum { MAX_WRITE_LENGTH = 10 }; if ((i + MAX_WRITE_LENGTH) > len) { write_length = len - i; } else { write_length = MAX_WRITE_LENGTH; } privoxy_millisleep(delay); if (ssl_send_data(ssl_attr, buf + i, write_length) < 0) { return -1; } i += write_length; } return 0; } /********************************************************************* * * Function : ssl_flush_socket * * Description : Send any pending "buffered" content with given * SSL connection. Alternative to function flush_socket. * * Parameters : * 1 : ssl_attr = SSL context to send buffer to * 2 : iob = The I/O buffer to flush, usually csp->iob. * * Returns : On success, the number of bytes send are returned (zero * indicates nothing was sent). On error, -1 is returned. * *********************************************************************/ extern long ssl_flush_socket(struct ssl_attr *ssl_attr, struct iob *iob) { /* Computing length of buffer part to send */ long len = iob->eod - iob->cur; if (len <= 0) { return(0); } /* Sending data to given SSl context */ if (ssl_send_data(ssl_attr, (const unsigned char *)iob->cur, (size_t)len) < 0) { return -1; } iob->eod = iob->cur = iob->buf; return(len); } /********************************************************************* * * Function : close_client_and_server_ssl_connections * * Description : Checks if client or server should use secured * connection over SSL and if so, closes all of them. * * Parameters : * 1 : csp = Current client state (buffers, headers, etc...) * * Returns : N/A * *********************************************************************/ extern void close_client_and_server_ssl_connections(struct client_state *csp) { if (client_use_ssl(csp) == 1) { close_client_ssl_connection(csp); } if (server_use_ssl(csp) == 1) { close_server_ssl_connection(csp); } } /********************************************************************* * * Function : tunnel_established_successfully * * Description : Check if parent proxy server response contains * information about successfully created connection with * destination server. (HTTP/... 2xx ...) * * Parameters : * 1 : server_response = Buffer with parent proxy server response * 2 : response_len = Length of server_response * * Returns : 1 => Connection created successfully * 0 => Connection wasn't created successfully * *********************************************************************/ extern int tunnel_established_successfully(const char *server_response, unsigned int response_len) { unsigned int pos = 0; if (server_response == NULL) { return 0; } /* Tests if "HTTP/" string is at the begin of received response */ if (strncmp(server_response, "HTTP/", 5) != 0) { return 0; } for (pos = 0; pos < response_len; pos++) { if (server_response[pos] == ' ') { break; } } /* * response_len -3 because of buffer end, response structure and 200 code. * There must be at least 3 chars after space. * End of buffer: ... 2xx'\0' * pos = | */ if (pos >= (response_len - 3)) { return 0; } /* Test HTTP status code */ if (server_response[pos + 1] != '2') { return 0; } return 1; } /********************************************************************* * * Function : free_certificate_chain * * Description : Frees certificates linked list. This linked list is * used to save information about certificates in * trusted chain. * * Parameters : * 1 : csp = Current client state (buffers, headers, etc...) * * Returns : N/A * *********************************************************************/ extern void free_certificate_chain(struct client_state *csp) { struct certs_chain *cert = csp->server_certs_chain.next; /* Cleaning buffers */ memset(csp->server_certs_chain.info_buf, 0, sizeof(csp->server_certs_chain.info_buf)); memset(csp->server_certs_chain.file_buf, 0, sizeof(csp->server_certs_chain.file_buf)); csp->server_certs_chain.next = NULL; /* Freeing memory in whole linked list */ while (cert != NULL) { struct certs_chain *cert_for_free = cert; cert = cert->next; freez(cert_for_free); } } /********************************************************************* * * Function : ssl_send_certificate_error * * Description : Sends info about invalid server certificate to client. * Sent message is including all trusted chain certificates, * that can be downloaded in web browser. * * Parameters : * 1 : csp = Current client state (buffers, headers, etc...) * * Returns : N/A * *********************************************************************/ extern void ssl_send_certificate_error(struct client_state *csp) { struct ssl_attr *ssl_attr = &csp->ssl_client_attr; size_t message_len = 0; int ret = 0; struct certs_chain *cert = NULL; const size_t head_length = 63; /* Header of message with certificate information */ const char message_begin[] = "HTTP/1.1 200 OK\r\n" "Content-Type: text/html\r\n" "Connection: close\r\n\r\n" "\n" "Server certificate verification failed\n" "

Server certificate verification failed

\n" "

Privoxy was unable " "to securely connect to the destination server.

" "

Reason: "; const char message_end[] = "\r\n\r\n"; char reason[INVALID_CERT_INFO_BUF_SIZE]; memset(reason, 0, sizeof(reason)); /* Get verification message from verification return code */ ssl_crt_verify_info(reason, sizeof(reason), csp); /* * Computing total length of message with all certificates inside */ message_len = strlen(message_begin) + strlen(message_end) + strlen(reason) + strlen("

") + 1; cert = &(csp->server_certs_chain); while (cert->next != NULL) { size_t base64_len = 4 * ((strlen(cert->file_buf) + 2) / 3) + 1; message_len += strlen(cert->info_buf) + strlen("
\n")
                     +  base64_len + strlen("Download certificate");
      cert = cert->next;
   }

   /*
    * Joining all blocks in one long message
    */
   char message[message_len];
   memset(message, 0, message_len);

   strlcpy(message, message_begin, message_len);
   strlcat(message, reason       , message_len);
   strlcat(message, "

" , message_len); cert = &(csp->server_certs_chain); while (cert->next != NULL) { size_t olen = 0; size_t base64_len = 4 * ((strlen(cert->file_buf) + 2) / 3) + 1; /* +1 for terminating null*/ char base64_buf[base64_len]; memset(base64_buf, 0, base64_len); /* Encoding certificate into base64 code */ ret = ssl_base64_encode((unsigned char*)base64_buf, base64_len, &olen, (const unsigned char*)cert->file_buf, strlen(cert->file_buf)); if (ret != 0) { log_error(LOG_LEVEL_ERROR, "Encoding to base64 failed, buffer is to small"); } strlcat(message, "
",        message_len);
      strlcat(message, cert->info_buf, message_len);
      strlcat(message, "
\n", message_len); if (ret == 0) { strlcat(message, "Download certificate", message_len); } cert = cert->next; } strlcat(message, message_end, message_len); /* * Sending final message to client */ ssl_send_data(ssl_attr, (const unsigned char *)message, strlen(message)); free_certificate_chain(csp); log_error(LOG_LEVEL_CRUNCH, "Certificate error: %s: https://%s%s", reason, csp->http->hostport, csp->http->path); log_error(LOG_LEVEL_CLF, "%s - - [%T] \"%s https://%s%s %s\" 200 %u", csp->ip_addr_str, csp->http->gpc, csp->http->hostport, csp->http->path, csp->http->version, message_len-head_length); } /********************************************************************* * * Function : file_exists * * Description : Tests if file exists and is readable. * * Parameters : * 1 : path = Path to tested file. * * Returns : 1 => File exists and is readable. * 0 => File doesn't exist or is not readable. * *********************************************************************/ extern int file_exists(const char *path) { FILE *f; if ((f = fopen(path, "r")) != NULL) { fclose(f); return 1; } return 0; } /********************************************************************* * * Function : make_certs_path * * Description : Creates path to file from three pieces. This function * takes parameters and puts them in one new mallocated * char * in correct order. Returned variable must be freed * by caller. This function is mainly used for creating * paths of certificates and keys files. * * Parameters : * 1 : conf_dir = Name/path of directory where is the file. * '.' can be used for current directory. * 2 : file_name = Name of file in conf_dir without suffix. * 3 : suffix = Suffix of given file_name. * * Returns : path => Path was built up successfully * NULL => Path can't be built up * *********************************************************************/ extern char *make_certs_path(const char *conf_dir, const char *file_name, const char *suffix) { /* Test if all given parameters are valid */ if (conf_dir == NULL || *conf_dir == '\0' || file_name == NULL || *file_name == '\0' || suffix == NULL || *suffix == '\0') { log_error(LOG_LEVEL_ERROR, "make_certs_path failed: bad input parameters"); return NULL; } char *path = NULL; size_t path_size = strlen(conf_dir) + strlen(file_name) + strlen(suffix) + 2; /* Setting delimiter and editing path length */ #if defined(_WIN32) || defined(__OS2__) char delim[] = "\\"; path_size += 1; #else /* ifndef _WIN32 || __OS2__ */ char delim[] = "/"; #endif /* ifndef _WIN32 || __OS2__ */ /* * Building up path from many parts */ #if defined(unix) if (*conf_dir != '/' && basedir && *basedir) { /* * Replacing conf_dir with basedir. This new variable contains * absolute path to cwd. */ path_size += strlen(basedir) + 2; path = zalloc_or_die(path_size); strlcpy(path, basedir, path_size); strlcat(path, delim, path_size); strlcat(path, conf_dir, path_size); strlcat(path, delim, path_size); strlcat(path, file_name, path_size); strlcat(path, suffix, path_size); } else #endif /* defined unix */ { path = zalloc_or_die(path_size); strlcpy(path, conf_dir, path_size); strlcat(path, delim, path_size); strlcat(path, file_name, path_size); strlcat(path, suffix, path_size); } return path; } /********************************************************************* * * Function : get_certificate_serial * * Description : Computes serial number for new certificate from host * name hash. This hash must be already saved in csp * structure. * * Parameters : * 1 : csp = Current client state (buffers, headers, etc...) * * Returns : Serial number for new certificate * *********************************************************************/ extern unsigned long get_certificate_serial(struct client_state *csp) { unsigned long exp = 1; unsigned long serial = 0; int i = CERT_SERIAL_NUM_LENGTH; for (; i >= 0; i--) { serial += exp * (unsigned)csp->http->hash_of_host[i]; exp *= 256; } return serial; } /********************************************************************* * * Function : generate_certificate_valid_date * * Description : Turns a time_t into the format expected by mbedTLS. * * Parameters : * 1 : time_spec = The timestamp to convert * 2 : buffer = The buffer to write the date to * 3 : buffer_size = The size of the buffer * 4 : fmt = format * * Returns : 0 => The conversion worked * 1 => The conversion failed * *********************************************************************/ static int generate_certificate_valid_date(time_t time_spec, char *buffer, size_t buffer_size, const char *fmt) { struct tm valid_date; struct tm *timeptr; size_t ret; timeptr = privoxy_gmtime_r(&time_spec, &valid_date); if (NULL == timeptr) { return 1; } ret = strftime(buffer, buffer_size, fmt, timeptr); if (ret <= 0) { return 1; } return 0; } /********************************************************************* * * Function : get_certificate_valid_from_date * * Description : Generates a "valid from" date in the format * expected by mbedTLS. * * Parameters : * 1 : buffer = The buffer to write the date to * 2 : buffer_size = The size of the buffer * 3 : fmt = format * * Returns : 0 => The generation worked * 1 => The generation failed * *********************************************************************/ extern int get_certificate_valid_from_date(char *buffer, size_t buffer_size, const char *fmt) { time_t time_spec; time_spec = time(NULL); /* 1 month in the past */ time_spec -= 30 * 24 * 60 * 60; return generate_certificate_valid_date(time_spec, buffer, buffer_size, fmt); } /********************************************************************* * * Function : get_certificate_valid_to_date * * Description : Generates a "valid to" date in the format * expected by mbedTLS. * * Parameters : * 1 : buffer = The buffer to write the date to * 2 : buffer_size = The size of the buffer * 3 : fmt = format * * Returns : 0 => The generation worked * 1 => The generation failed * *********************************************************************/ extern int get_certificate_valid_to_date(char *buffer, size_t buffer_size, const char *fmt) { time_t time_spec; time_spec = time(NULL); /* Three months in the future */ time_spec += 90 * 24 * 60 * 60; return generate_certificate_valid_date(time_spec, buffer, buffer_size, fmt); } /********************************************************************* * * Function : host_is_ip_address * * Description : Checks whether or not a host is specified by * IP address. Does not actually validate the * address. * * Parameters : * 1 : host = The host name to check * * Returns : 1 => Yes * 0 => No * *********************************************************************/ extern int host_is_ip_address(const char *host) { const char *p; if (NULL != strstr(host, ":")) { /* Assume an IPv6 address. */ return 1; } for (p = host; *p; p++) { if ((*p != '.') && !privoxy_isdigit(*p)) { /* Not a dot or digit so it can't be an IPv4 address. */ return 0; } } /* * Host only consists of dots and digits so * assume that is an IPv4 address. */ return 1; }