/* Prevent Cross-site Request Forgery
*/
int prevent_csrf(t_session *session) {
char *referer, *slash;
int i, n;
if (strcmp(session->method, "POST") != 0) {
return 0;
}
if ((referer = get_http_header("Referer:", session->http_headers)) == NULL) {
return 0;
}
if (strncmp(referer, "http://", 7) == 0) {
referer += 7;
} else if (strncmp(referer, "https://", 8) == 0) {
referer += 8;
} else {
session->cookie = NULL;
log_error(session, "invalid referer while checking for CSRF");
return 1;
}
if ((slash = strchr(referer, '/')) != NULL) {
n = slash - referer;
} else {
n = strlen(referer);
}
for (i = 0; i < session->host->hostname.size; i++) {
if (strncasecmp(referer, *(session->host->hostname.item + i), n) == 0) {
return 0;
}
}
session->cookie = NULL;
if (session->body != NULL) {
log_exploit_attempt(session, "CSRF", session->body);
#ifdef ENABLE_TOMAHAWK
increment_counter(COUNTER_EXPLOIT);
#endif
#ifdef ENABLE_MONITOR
if (session->config->monitor_enabled) {
monitor_counter_exploit_attempt(session);
}
#endif
} else {
log_error(session, "CSRF attempt detected with no request body");
}
#ifdef ENABLE_MONITOR
if (session->config->monitor_enabled) {
monitor_counter_exploit_attempt(session);
}
#endif
return 1;
}
/* Validate URL
*/
bool validate_url(t_session *session) {
if (valid_uri(session->uri, session->host->allow_dot_files)) {
if (session->host->secure_url == false) {
return true;
} else if (strstr(session->request_uri, "%00") == NULL) {
return true;
} else {
session->return_code = 403;
}
} else {
session->return_code = (session->request_method == PUT) ? 403 : 404;
}
log_exploit_attempt(session, "invalid URL", NULL);
#ifdef ENABLE_TOMAHAWK
increment_counter(COUNTER_EXPLOIT);
#endif
#ifdef ENABLE_MONITOR
if (session->config->monitor_enabled) {
monitor_counter_exploit_attempt(session);
}
#endif
session->error_cause = ec_INVALID_URL;
return false;
}
/* Prevent SQL injection
*/
static int prevent_sqli_str(t_session *session, char *str, int length) {
char *data;
t_sqli_pattern *pattern;
int result = 0;
if ((str == NULL) || (length <= 0)) {
return 0;
}
if ((data = (char*)malloc(length + 1)) == NULL) {
return -1;
}
memcpy(data, str, length);
data[length] = '\0';
url_decode(data);
pattern = sqli_patterns;
while (pattern != NULL) {
if (regexec(&(pattern->regex), data, 0, NULL, 0) != REG_NOMATCH) {
log_exploit_attempt(session, "SQLi", str);
#ifdef ENABLE_TOMAHAWK
increment_counter(COUNTER_EXPLOIT);
#endif
#ifdef ENABLE_MONITOR
if (session->config->monitor_enabled) {
monitor_counter_exploit_attempt(session);
}
#endif
result = 1;
break;
}
pattern = pattern->next;
}
free(data);
return result;
}
/* Prevent cross-site scripting.
*/
int prevent_xss(t_session *session) {
int result = 0;
short low, high;
char *str, value;
if ((str = session->vars) == NULL) {
return 0;
}
while (*str != '\0') {
if ((value = *str) == '%') {
if ((high = hex_to_int(*(str + 1))) != -1) {
if ((low = hex_to_int(*(str + 2))) != -1) {
value = (char)(high<<4) + low;
}
}
}
if ((value == '\"') || (value == '<') || (value == '>') || (value == '\'')) {
*str = '_';
result += 1;
}
str++;
}
if (result > 0) {
log_exploit_attempt(session, "XSS", session->vars);
#ifdef ENABLE_TOMAHAWK
increment_counter(COUNTER_EXPLOIT);
#endif
#ifdef ENABLE_MONITOR
if (session->config->monitor_enabled) {
monitor_counter_exploit_attempt(session);
}
#endif
}
return result;
}
/* Serve the client that connected to the webserver
*/
static int serve_client(t_session *session) {
int result, length, auth_result;
char *search, *qmark, chr, *client_ip;
t_host *host_record;
t_access access;
t_deny_body *deny_body;
t_req_method request_method;
t_ip_addr ip;
#ifdef ENABLE_TOOLKIT
int i;
t_toolkit_options toolkit_options;
#endif
#ifdef ENABLE_RPROXY
t_rproxy *rproxy;
#endif
#ifdef ENABLE_DEBUG
session->current_task = "fetch & parse request";
#endif
if ((result = fetch_request(session)) != 200) {
session->request_method = GET;
return result;
} else if ((result = parse_request(session, session->header_length + session->content_length)) != 200) {
session->request_method = GET;
return result;
}
#ifdef ENABLE_DEBUG
session->current_task = "serve client";
#endif
session->time = time(NULL);
/* Hide reverse proxies
*/
if (in_iplist(session->config->hide_proxy, &(session->ip_address))) {
if ((client_ip = get_http_header(hs_forwarded, session->http_headers)) != NULL) {
if ((search = strrchr(client_ip, ',')) != NULL) {
client_ip = search + 1;
}
while ((*client_ip == ' ') && (*client_ip != '\0')) {
client_ip++;
}
if (*client_ip != '\0') {
if (parse_ip(client_ip, &ip) != -1) {
if (reposition_client(session, &ip) != -1) {
copy_ip(&(session->ip_address), &ip);
}
}
}
}
}
/* Find host record
*/
if (session->hostname != NULL) {
remove_port_from_hostname(session->hostname, session->binding);
if ((host_record = get_hostrecord(session->config->first_host, session->hostname, session->binding)) != NULL) {
session->host = host_record;
#ifdef ENABLE_TOMAHAWK
session->last_host = host_record;
#endif
}
}
session->host->access_time = session->time;
#ifdef ENABLE_SSL
/* SSL client authentication
*/
if (session->binding->use_ssl) {
if ((session->host->ca_certificate != NULL) && (ssl_has_peer_cert(&(session->ssl_context)) == false)) {
log_error(session, "missing client SSL certificate");
return 440;
}
}
#endif
/* Enforce usage of SSL
*/
#ifdef ENABLE_SSL
if (session->host->require_ssl && (session->binding->use_ssl == false)) {
if ((qmark = strchr(session->uri, '?')) != NULL) {
*qmark = '\0';
session->vars = qmark + 1;
session->uri_len = strlen(session->uri);
}
session->cause_of_301 = require_ssl;
return 301;
}
#endif
/* Deny matching bodies
*/
if (session->body != NULL) {
chr = *(session->body + session->content_length);
*(session->body + session->content_length) = '\0';
deny_body = session->host->deny_body;
while (deny_body != NULL) {
if (strpcmp(session->body, &(deny_body->pattern)) == 0) {
if ((session->config->ban_on_denied_body > 0) && (ip_allowed(&(session->ip_address), session->config->banlist_mask) != deny)) {
ban_ip(&(session->ip_address), session->config->ban_on_denied_body, session->config->kick_on_ban);
log_system(session, "Client banned because of denied body");
#ifdef ENABLE_MONITOR
if (session->config->monitor_enabled) {
monitor_counter_ban(session);
}
#endif
}
log_exploit_attempt(session, "denied body", session->body);
#ifdef ENABLE_TOMAHAWK
increment_counter(COUNTER_EXPLOIT);
#endif
#ifdef ENABLE_MONITOR
if (session->config->monitor_enabled) {
monitor_counter_exploit_attempt(session);
}
#endif
*(session->body + session->content_length) = chr;
return 403;
}
deny_body = deny_body->next;
}
*(session->body + session->content_length) = chr;
}
#ifdef ENABLE_RPROXY
/* Reverse proxy
*/
rproxy = session->host->rproxy;
while (rproxy != NULL) {
if (rproxy_match(rproxy, session->request_uri)) {
if (rproxy_loop_detected(session->http_headers)) {
return 508;
}
if ((qmark = strchr(session->uri, '?')) != NULL) {
*qmark = '\0';
session->vars = qmark + 1;
}
if (validate_url(session) == false) {
return -1;
}
if ((session->vars != NULL) && (session->host->secure_url)) {
if (forbidden_chars_present(session->vars)) {
return 403;
}
}
if (duplicate_host(session) == false) {
return 500;
} else if ((result = uri_to_path(session)) != 200) {
return result;
} else if (load_user_config(session) == -1) {
return 500;
} else if ((result = copy_directory_settings(session)) != 200) {
return result;
}
switch (access = allow_client(session)) {
case deny:
log_error(session, fb_accesslist);
return 403;
case allow:
break;
case pwd:
case unspecified:
if ((auth_result = http_authentication_result(session, access == unspecified)) != 200) {
return auth_result;
}
}
if (session->host->prevent_xss) {
prevent_xss(session);
}
if (session->host->prevent_csrf) {
prevent_csrf(session);
}
if (session->host->prevent_sqli) {
if ((result = prevent_sqli(session)) != 0) {
return result;
}
}
return proxy_request(session, rproxy);
}
rproxy = rproxy->next;
}
#endif
/* Actions based on request method
*/
switch (session->request_method) {
case TRACE:
if (session->binding->enable_trace == false) {
return 501;
}
return handle_trace_request(session);
case PUT:
case DELETE:
if ((session->binding->enable_alter == false) && (session->host->webdav_app == false)) {
return 501;
}
break;
case unknown:
return 400;
case unsupported:
if (session->host->webdav_app == false) {
return 501;
}
break;
default:
break;
}
#ifdef ENABLE_TOOLKIT
/* URL toolkit
*/
#ifdef ENABLE_SSL
init_toolkit_options(&toolkit_options, session->host->website_root, session->config->url_toolkit,
session->binding->use_ssl, session->host->allow_dot_files, session->http_headers);
#else
init_toolkit_options(&toolkit_options, session->host->website_root, session->config->url_toolkit,
session->host->allow_dot_files, session->http_headers);
#endif
if ((session->request_method != PUT) && (session->request_method != DELETE)) {
for (i = 0; i < session->host->toolkit_rules.size; i++) {
if ((result = use_toolkit(session->uri, session->host->toolkit_rules.item[i], &toolkit_options)) == UT_ERROR) {
return 500;
}
if ((toolkit_options.ban > 0) && (ip_allowed(&(session->ip_address), session->config->banlist_mask) != deny)) {
ban_ip(&(session->ip_address), toolkit_options.ban, session->config->kick_on_ban);
log_system(session, "Client banned because of URL match in UrlToolkit rule");
#ifdef ENABLE_MONITOR
if (session->config->monitor_enabled) {
monitor_counter_ban(session);
}
#endif
return 403;
}
session->toolkit_fastcgi = toolkit_options.fastcgi_server;
if (toolkit_options.new_url != NULL) {
if (register_tempdata(&(session->tempdata), toolkit_options.new_url, tc_data) == -1) {
free(toolkit_options.new_url);
return 500;
}
session->uri = toolkit_options.new_url;
}
if (result == UT_REDIRECT) {
if ((session->location = strdup(toolkit_options.new_url)) == NULL) {
return -1;
}
session->cause_of_301 = location;
return 301;
}
if (result == UT_DENY_ACCESS) {
log_error(session, "access denied via URL toolkit rule");
return 403;
}
if (toolkit_options.expire > -1) {
session->expires = toolkit_options.expire;
}
}
}
#endif
/* Find GET data
*/
if ((qmark = strchr(session->uri, '?')) != NULL) {
*qmark = '\0';
session->vars = qmark + 1;
}
url_decode(session->uri);
session->uri_len = strlen(session->uri);
if ((session->vars != NULL) && (session->host->secure_url)) {
if (forbidden_chars_present(session->vars)) {
return 403;
}
}
if (duplicate_host(session) == false) {
return 500;
}
if (validate_url(session) == false) {
return -1;
}
if ((result = uri_to_path(session)) != 200) {
return result;
}
/* Load configfile from directories
*/
if (load_user_config(session) == -1) {
return 500;
}
if ((result = copy_directory_settings(session)) != 200) {
return result;
}
switch (access = allow_client(session)) {
case deny:
log_error(session, fb_accesslist);
return 403;
case allow:
break;
case pwd:
case unspecified:
if ((auth_result = http_authentication_result(session, access == unspecified)) != 200) {
return auth_result;
}
}
switch (is_directory(session->file_on_disk)) {
case error:
return 500;
case yes:
session->uri_is_dir = true;
break;
case no:
if (((session->request_method != PUT) || session->host->webdav_app) && (session->host->enable_path_info)) {
if ((result = get_path_info(session)) != 200) {
return result;
}
}
break;
case no_access:
log_error(session, fb_filesystem);
return 403;
case not_found:
if (session->request_method == DELETE) {
return 404;
}
}
#ifdef ENABLE_TOOLKIT
if ((session->toolkit_fastcgi == NULL) && session->uri_is_dir) {
#else
if (session->uri_is_dir) {
#endif
length = strlen(session->file_on_disk);
if (*(session->file_on_disk + length - 1) == '/') {
strcpy(session->file_on_disk + length, session->host->start_file);
} else {
return 301;
}
}
if (get_target_extension(session) == -1) {
return 500;
}
if (((session->request_method != PUT) && (session->request_method != DELETE)) || session->host->webdav_app) {
check_target_is_cgi(session);
}
/* Handle request based on request method
*/
request_method = session->request_method;
if (session->host->webdav_app) {
if ((request_method == PUT) || (request_method == DELETE)) {
request_method = POST;
}
}
switch (request_method) {
case GET:
case HEAD:
if (session->cgi_type != no_cgi) {
session->body = NULL;
result = execute_cgi(session);
#ifdef ENABLE_XSLT
} else if (can_transform_with_xslt(session)) {
result = handle_xml_file(session);
#endif
} else {
result = send_file(session);
}
if (result == 404) {
#ifdef ENABLE_XSLT
if ((session->host->show_index != NULL) && (session->uri[session->uri_len - 1] == '/')) {
result = show_index(session);
}
#endif
#ifdef ENABLE_MONITOR
} else if (session->config->monitor_enabled) {
if ((result == 200) && (session->host->monitor_host)) {
unlink(session->file_on_disk);
}
#endif
}
if ((session->request_method == GET) && (session->cgi_type == no_cgi) && (session->directory != NULL)) {
if (session->directory->run_on_download != NULL) {
run_program(session, session->directory->run_on_download, result);
}
}
break;
case POST:
case unsupported:
if (session->cgi_type != no_cgi) {
result = execute_cgi(session);
#ifdef ENABLE_XSLT
} else if (can_transform_with_xslt(session)) {
result = handle_xml_file(session);
#endif
} else {
result = 405;
}
break;
case PUT:
result = handle_put_request(session);
if (((result == 201) || (result == 204)) && (session->host->run_on_alter != NULL)) {
run_program(session, session->host->run_on_alter, result);
}
break;
case DELETE:
result = handle_delete_request(session);
if ((result == 204) && (session->host->run_on_alter != NULL)) {
run_program(session, session->host->run_on_alter, result);
}
break;
default:
result = 400;
}
return result;
}
/* Handle timeout upon sending request
*/
static void handle_timeout(t_session *session) {
if ((session->config->ban_on_timeout > 0) && (ip_allowed(&(session->ip_address), session->config->banlist_mask) != deny)) {
ban_ip(&(session->ip_address), session->config->ban_on_timeout, session->config->kick_on_ban);
log_system(session, "Client banned because of connection timeout");
#ifdef ENABLE_MONITOR
if (session->config->monitor_enabled) {
monitor_counter_ban(session);
}
#endif
} else {
log_system(session, "Timeout while waiting for request");
}
}
/* Request has been handled, handle the return code.
*/
static void handle_request_result(t_session *session, int result) {
char *hostname;
#ifdef ENABLE_DEBUG
session->current_task = "handle request result";
#endif
if (result == -1) switch (session->error_cause) {
case ec_MAX_REQUESTSIZE:
log_system(session, "Maximum request size reached");
session->return_code = 413;
send_code(session);
if ((session->config->ban_on_max_request_size > 0) && (ip_allowed(&(session->ip_address), session->config->banlist_mask) != deny)) {
ban_ip(&(session->ip_address), session->config->ban_on_max_request_size, session->config->kick_on_ban);
log_system(session, "Client banned because of sending a too large request");
#ifdef ENABLE_MONITOR
if (session->config->monitor_enabled) {
monitor_counter_ban(session);
}
#endif
}
break;
case ec_TIMEOUT:
if (session->kept_alive == 0) {
session->return_code = 408;
send_code(session);
handle_timeout(session);
}
break;
case ec_CLIENT_DISCONNECTED:
if (session->kept_alive == 0) {
log_system(session, "Client disconnected");
}
break;
case ec_SOCKET_READ_ERROR:
if (errno != ECONNRESET) {
log_system(session, "Error while reading request");
}
break;
case ec_SOCKET_WRITE_ERROR:
log_request(session);
break;
case ec_FORCE_QUIT:
log_system(session, "Client kicked");
break;
case ec_SQL_INJECTION:
if ((session->config->ban_on_sqli > 0) && (ip_allowed(&(session->ip_address), session->config->banlist_mask) != deny)) {
ban_ip(&(session->ip_address), session->config->ban_on_sqli, session->config->kick_on_ban);
hostname = (session->hostname != NULL) ? session->hostname : unknown_host;
log_system(session, "Client banned because of SQL injection on %s", hostname);
#ifdef ENABLE_MONITOR
if (session->config->monitor_enabled) {
monitor_counter_ban(session);
}
#endif
}
session->return_code = 441;
send_code(session);
log_request(session);
break;
case ec_INVALID_URL:
if ((session->config->ban_on_invalid_url > 0) && (ip_allowed(&(session->ip_address), session->config->banlist_mask) != deny)) {
ban_ip(&(session->ip_address), session->config->ban_on_invalid_url, session->config->kick_on_ban);
hostname = (session->hostname != NULL) ? session->hostname : unknown_host;
log_system(session, "Client banned because of invalid URL on %s", hostname);
#ifdef ENABLE_MONITOR
if (session->config->monitor_enabled) {
monitor_counter_ban(session);
}
#endif
}
send_code(session);
break;
default:
if (session->data_sent == false) {
session->return_code = 500;
send_code(session);
}
} else switch (result) {
case 200:
break;
case 201:
case 204:
case 304:
case 412:
if (session->data_sent == false) {
session->return_code = result;
send_header(session);
send_buffer(session, "Content-Length: 0\r\n\r\n", 21);
}
break;
case 411:
case 413:
session->keep_alive = false;
if (session->data_sent == false) {
session->return_code = result;
send_header(session);
send_buffer(session, "Content-Length: 0\r\n\r\n", 21);
}
break;
case 400:
log_garbage(session);
if (session->data_sent == false) {
session->return_code = 400;
if (send_code(session) == -1) {
session->keep_alive = false;
}
}
if ((session->config->ban_on_garbage > 0) && (ip_allowed(&(session->ip_address), session->config->banlist_mask) != deny)) {
ban_ip(&(session->ip_address), session->config->ban_on_garbage, session->config->kick_on_ban);
log_system(session, "Client banned because of sending garbage");
#ifdef ENABLE_MONITOR
if (session->config->monitor_enabled) {
monitor_counter_ban(session);
}
#endif
}
break;
case 401:
case 403:
case 404:
case 501:
case 503:
if (session->data_sent == false) {
switch (handle_error(session, result)) {
case -1:
session->keep_alive = false;
break;
case 200:
break;
default:
if (session->data_sent == false) {
session->return_code = result;
if (send_code(session) == -1) {
session->keep_alive = false;
}
}
}
}
break;
case 500:
session->keep_alive = false;
default:
if (session->data_sent == false) {
session->return_code = result;
send_code(session);
}
}
if ((result > 0) && (result != 400)) {
log_request(session);
} else {
session->keep_alive = false;
}
}
