const char filters_rcs[] = "$Id: filters.c,v 1.15 2001/06/03 11:03:48 oes Exp $"; /********************************************************************* * * File : $Source: /cvsroot/ijbswa/current/filters.c,v $ * * Purpose : Declares functions to parse/crunch headers and pages. * Functions declared include: * `acl_addr', `add_stats', `block_acl', `block_imageurl', * `block_url', `url_actions', `domaincmp', `dsplit', * `filter_popups', `forward_url', 'redirect_url', * `ij_untrusted_url', `intercept_url', `re_process_buffer', * `show_proxy_args', 'ijb_send_banner', and `trust_url' * * Copyright : Written by and Copyright (C) 2001 the SourceForge * IJBSWA team. http://ijbswa.sourceforge.net * * Based on the Internet Junkbuster originally written * by and Copyright (C) 1997 Anonymous Coders and * Junkbusters Corporation. http://www.junkbusters.com * * 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. * * Revisions : * $Log: filters.c,v $ * Revision 1.15 2001/06/03 11:03:48 oes * Makefile/in * * introduced cgi.c * * actions.c: * * adapted to new enlist_unique arg format * * conf loadcfg.c * * introduced confdir option * * filters.c filtrers.h * * extracted-CGI relevant stuff * * jbsockets.c * * filled comment * * jcc.c * * support for new cgi mechansim * * list.c list.h * * functions for new list type: "map" * extended enlist_unique * * miscutil.c .h * introduced bindup() * * parsers.c parsers.h * * deleted const struct interceptors * * pcrs.c * added FIXME * * project.h * * added struct map * added struct http_response * changes struct interceptors to struct cgi_dispatcher * moved HTML stuff to cgi.h * * re_filterfile: * * changed * * showargs.c * NO TIME LEFT * * Revision 1.14 2001/06/01 10:30:55 oes * Added optional left-anchoring to domaincmp * * Revision 1.13 2001/05/31 21:21:30 jongfoster * Permissionsfile / actions file changes: * - Changed "permission" to "action" throughout * - changes to file format to allow string parameters * - Moved helper functions to actions.c * * Revision 1.12 2001/05/31 17:35:20 oes * * - Enhanced domain part globbing with infix and prefix asterisk * matching and optional unanchored operation * * Revision 1.11 2001/05/29 11:53:23 oes * "See why" link added to "blocked" page * * Revision 1.10 2001/05/29 09:50:24 jongfoster * Unified blocklist/imagelist/permissionslist. * File format is still under discussion, but the internal changes * are (mostly) done. * * Also modified interceptor behaviour: * - We now intercept all URLs beginning with one of the following * prefixes (and *only* these prefixes): * * http://i.j.b/ * * http://ijbswa.sf.net/config/ * * http://ijbswa.sourceforge.net/config/ * - New interceptors "home page" - go to http://i.j.b/ to see it. * - Internal changes so that intercepted and fast redirect pages * are not replaced with an image. * - Interceptors now have the option to send a binary page direct * to the client. (i.e. ijb-send-banner uses this) * - Implemented show-url-info interceptor. (Which is why I needed * the above interceptors changes - a typical URL is * "http://i.j.b/show-url-info?url=www.somesite.com/banner.gif". * The previous mechanism would not have intercepted that, and * if it had been intercepted then it then it would have replaced * it with an image.) * * Revision 1.9 2001/05/27 22:17:04 oes * * - re_process_buffer no longer writes the modified buffer * to the client, which was very ugly. It now returns the * buffer, which it is then written by chat. * * - content_length now adjusts the Content-Length: header * for modified documents rather than crunch()ing it. * (Length info in csp->content_length, which is 0 for * unmodified documents) * * - For this to work, sed() is called twice when filtering. * * Revision 1.8 2001/05/26 17:13:28 jongfoster * Filled in a function comment. * * Revision 1.7 2001/05/26 15:26:15 jongfoster * ACL feature now provides more security by immediately dropping * connections from untrusted hosts. * * Revision 1.6 2001/05/26 00:28:36 jongfoster * Automatic reloading of config file. * Removed obsolete SIGHUP support (Unix) and Reload menu option (Win32). * Most of the global variables have been moved to a new * struct configuration_spec, accessed through csp->config->globalname * Most of the globals remaining are used by the Win32 GUI. * * Revision 1.5 2001/05/25 22:34:30 jongfoster * Hard tabs->Spaces * * Revision 1.4 2001/05/22 18:46:04 oes * * - Enabled filtering banners by size rather than URL * by adding patterns that replace all standard banner * sizes with the "Junkbuster" gif to the re_filterfile * * - Enabled filtering WebBugs by providing a pattern * which kills all 1x1 images * * - Added support for PCRE_UNGREEDY behaviour to pcrs, * which is selected by the (nonstandard and therefore * capital) letter 'U' in the option string. * It causes the quantifiers to be ungreedy by default. * Appending a ? turns back to greedy (!). * * - Added a new interceptor ijb-send-banner, which * sends back the "Junkbuster" gif. Without imagelist or * MSIE detection support, or if tinygif = 1, or the * URL isn't recognized as an imageurl, a lame HTML * explanation is sent instead. * * - Added new feature, which permits blocking remote * script redirects and firing back a local redirect * to the browser. * The feature is conditionally compiled, i.e. it * can be disabled with --disable-fast-redirects, * plus it must be activated by a "fast-redirects" * line in the config file, has its own log level * and of course wants to be displayed by show-proxy-args * Note: Boy, all the #ifdefs in 1001 locations and * all the fumbling with configure.in and acconfig.h * were *way* more work than the feature itself :-( * * - Because a generic redirect template was needed for * this, tinygif = 3 now uses the same. * * - Moved GIFs, and other static HTTP response templates * to project.h * * - Some minor fixes * * - Removed some >400 CRs again (Jon, you really worked * a lot! ;-) * * Revision 1.3 2001/05/20 16:44:47 jongfoster * Removing last hardcoded JunkBusters.com URLs. * * Revision 1.2 2001/05/20 01:21:20 jongfoster * Version 2.9.4 checkin. * - Merged popupfile and cookiefile, and added control over PCRS * filtering, in new "permissionsfile". * - Implemented LOG_LEVEL_FATAL, so that if there is a configuration * file error you now get a message box (in the Win32 GUI) rather * than the program exiting with no explanation. * - Made killpopup use the PCRS MIME-type checking and HTTP-header * skipping. * - Removed tabs from "config" * - Moved duplicated url parsing code in "loaders.c" to a new funcition. * - Bumped up version number. * * Revision 1.1.1.1 2001/05/15 13:58:52 oes * Initial import of version 2.9.3 source tree * * *********************************************************************/ #include "config.h" #include #include #include #include #include #ifndef _WIN32 #include #include #else #include #endif #include "project.h" #include "filters.h" #include "encode.h" #include "jcc.h" #include "showargs.h" #include "parsers.h" #include "ssplit.h" #include "gateway.h" #include "jbsockets.h" #include "errlog.h" #include "jbsockets.h" #include "miscutil.h" #include "actions.h" #include "cgi.h" #ifdef _WIN32 #include "win32.h" #endif const char filters_h_rcs[] = FILTERS_H_VERSION; /* Fix a problem with Solaris. There should be no effect on other * platforms. * Solaris's isspace() is a macro which uses it's argument directly * as an array index. Therefore we need to make sure that high-bit * characters generate +ve values, and ideally we also want to make * the argument match the declared parameter type of "int". */ #define ijb_isdigit(__X) isdigit((int)(unsigned char)(__X)) #ifdef ACL_FILES /********************************************************************* * * Function : block_acl * * Description : Block this request? * Decide yes or no based on ACL file. * * Parameters : * 1 : dst = The proxy or gateway address this is going to. * Or NULL to check all possible targets. * 2 : csp = Current client state (buffers, headers, etc...) * Also includes the client IP address. * * Returns : 0 = FALSE (don't block) and 1 = TRUE (do block) * *********************************************************************/ int block_acl(struct access_control_addr *dst, struct client_state *csp) { struct file_list *fl; struct access_control_list *a, *acl; /* if not using an access control list, then permit the connection */ if (((fl = csp->alist) == NULL) || ((acl = (struct access_control_list *) fl->f) == NULL)) { return(0); } /* search the list */ for (a = acl->next ; a ; a = a->next) { if ((csp->ip_addr_long & a->src->mask) == a->src->addr) { if (dst == NULL) { /* Just want to check if they have any access */ if (a->action == ACL_PERMIT) { return(0); } } else if ( ((dst->addr & a->dst->mask) == a->dst->addr) && ((dst->port == a->dst->port) || (a->dst->port == 0))) { if (a->action == ACL_PERMIT) { return(0); } else { return(1); } } } } return(1); } /********************************************************************* * * Function : acl_addr * * Description : Called from `load_aclfile' to parse an ACL address. * * Parameters : * 1 : aspec = String specifying ACL address. * 2 : aca = struct access_control_addr to fill in. * * Returns : 0 => Ok, everything else is an error. * *********************************************************************/ int acl_addr(char *aspec, struct access_control_addr *aca) { int i, masklength, port; char *p; masklength = 32; port = 0; if ((p = strchr(aspec, '/'))) { *p++ = '\0'; if (ijb_isdigit(*p) == 0) { return(-1); } masklength = atoi(p); } if ((masklength < 0) || (masklength > 32)) { return(-1); } if ((p = strchr(aspec, ':'))) { *p++ = '\0'; if (ijb_isdigit(*p) == 0) { return(-1); } port = atoi(p); } aca->port = port; aca->addr = ntohl(resolve_hostname_to_ip(aspec)); if (aca->addr == -1) { log_error(LOG_LEVEL_ERROR, "can't resolve address for %s", aspec); return(-1); } /* build the netmask */ aca->mask = 0; for (i=1; i <= masklength ; i++) { aca->mask |= (1 << (32 - i)); } /* now mask off the host portion of the ip address * (i.e. save on the network portion of the address). */ aca->addr = aca->addr & aca->mask; return(0); } #endif /* def ACL_FILES */ /********************************************************************* * * Function : block_url * * Description : Called from `chat'. Check to see if we need to block this. * * Parameters : * 1 : http = http_request request to "check" for blocked * 2 : csp = Current client state (buffers, headers, etc...) * * Returns : NULL => unblocked, else string to HTML block description. * *********************************************************************/ char *block_url(struct http_request *http, struct client_state *csp) { char *p; int n; int factor = 2; if ((csp->action->flags & ACTION_BLOCK) == 0) { return(NULL); } else { #ifdef FORCE_LOAD factor++; #endif /* def FORCE_LOAD */ n = strlen(CBLOCK); n += factor * strlen(http->hostport); n += factor * strlen(http->path); p = (char *)malloc(n); #ifdef FORCE_LOAD sprintf(p, CBLOCK, http->hostport, http->path, http->hostport, http->path, http->hostport, http->path); #else sprintf(p, CBLOCK, http->hostport, http->path, http->hostport, http->path); #endif /* def FORCE_LOAD */ return(p); } } #ifdef IMAGE_BLOCKING /********************************************************************* * * Function : block_imageurl * * Description : Given a URL which is blocked, decide whether to * send the "blocked" image or HTML. * * Parameters : * 1 : http = URL to check. * 2 : csp = Current client state (buffers, headers, etc...) * * Returns : True (nonzero) if URL is in image list, false (0) * otherwise * *********************************************************************/ int block_imageurl(struct http_request *http, struct client_state *csp) { #ifdef DETECT_MSIE_IMAGES if ((csp->accept_types & (ACCEPT_TYPE_IS_MSIE|ACCEPT_TYPE_MSIE_IMAGE|ACCEPT_TYPE_MSIE_HTML)) == (ACCEPT_TYPE_IS_MSIE|ACCEPT_TYPE_MSIE_IMAGE)) { return 1; } else if ((csp->accept_types & (ACCEPT_TYPE_IS_MSIE|ACCEPT_TYPE_MSIE_IMAGE|ACCEPT_TYPE_MSIE_HTML)) == (ACCEPT_TYPE_IS_MSIE|ACCEPT_TYPE_MSIE_HTML)) { return 0; } #endif return ((csp->action->flags & ACTION_IMAGE) != 0); } #endif /* def IMAGE_BLOCKING */ #ifdef TRUST_FILES /********************************************************************* * * Function : trust_url * * Description : Should we "trust" this URL? See "trustfile" line in config. * * Parameters : * 1 : http = http_request request for requested URL * 2 : csp = Current client state (buffers, headers, etc...) * * Returns : NULL => trusted, else string to HTML "untrusted" description. * *********************************************************************/ char *trust_url(struct http_request *http, struct client_state *csp) { struct file_list *fl; struct block_spec *b; struct url_spec url[1], **tl, *t; char *p, *h; char *hostport, *path, *refer; struct http_request rhttp[1]; int n; if (((fl = csp->tlist) == NULL) || ((b = fl->f) == NULL)) { return(NULL); } *url = dsplit(http->host); /* if splitting the domain fails, punt */ if (url->dbuf == NULL) return(NULL); memset(rhttp, '\0', sizeof(*rhttp)); for (b = b->next; b ; b = b->next) { if ((b->url->port == 0) || (b->url->port == http->port)) { if ((b->url->domain[0] == '\0') || (domaincmp(b->url, url) == 0)) { if ((b->url->path == NULL) || #ifdef REGEX (regexec(b->url->preg, http->path, 0, NULL, 0) == 0) #else (strncmp(b->url->path, http->path, b->url->pathlen) == 0) #endif ) { freez(url->dbuf); freez(url->dvec); if (b->reject == 0) return(NULL); hostport = url_encode(http->hostport); path = url_encode(http->path); if (csp->referrer) { refer = url_encode(csp->referrer); } else { refer = url_encode("undefined"); } n = strlen(CTRUST); n += strlen(hostport); n += strlen(path); n += strlen(refer); p = (char *)malloc(n); sprintf(p, CTRUST, hostport, path, refer); freez(hostport); freez(path); freez(refer); return(p); } } } } freez(url->dbuf); freez(url->dvec); if ((csp->referrer == NULL)|| (strlen(csp->referrer) <= 9)) { /* no referrer was supplied */ goto trust_url_not_trusted; } /* forge a URL from the referrer so we can use * convert_url() to parse it into its components. */ p = NULL; p = strsav(p, "GET "); p = strsav(p, csp->referrer + 9); /* skip over "Referer: " */ p = strsav(p, " HTTP/1.0"); parse_http_request(p, rhttp, csp); if (rhttp->cmd == NULL) { freez(p); goto trust_url_not_trusted; } freez(p); *url = dsplit(rhttp->host); /* if splitting the domain fails, punt */ if (url->dbuf == NULL) goto trust_url_not_trusted; for (tl = csp->config->trust_list; (t = *tl) ; tl++) { if ((t->port == 0) || (t->port == rhttp->port)) { if ((t->domain[0] == '\0') || domaincmp(t, url) == 0) { if ((t->path == NULL) || #ifdef REGEX (regexec(t->preg, rhttp->path, 0, NULL, 0) == 0) #else (strncmp(t->path, rhttp->path, t->pathlen) == 0) #endif ) { /* if the URL's referrer is from a trusted referrer, then * add the target spec to the trustfile as an unblocked * domain and return NULL (which means it's OK). */ FILE *fp; freez(url->dbuf); freez(url->dvec); if ((fp = fopen(csp->config->trustfile, "a"))) { h = NULL; h = strsav(h, "~"); h = strsav(h, http->hostport); p = http->path; if ((*p++ == '/') && (*p++ == '~')) { /* since this path points into a user's home space * be sure to include this spec in the trustfile. */ if ((p = strchr(p, '/'))) { *p = '\0'; h = strsav(h, http->path); h = strsav(h, "/"); } } free_http_request(rhttp); fprintf(fp, "%s\n", h); freez(h); fclose(fp); } return(NULL); } } } } trust_url_not_trusted: free_http_request(rhttp); hostport = url_encode(http->hostport); path = url_encode(http->path); if (csp->referrer) { refer = url_encode(csp->referrer); } else { refer = url_encode("undefined"); } n = strlen(CTRUST); n += strlen(hostport); n += strlen(path); n += strlen(refer); p = (char *)malloc(n); sprintf(p, CTRUST, hostport, path, refer); freez(hostport); freez(path); freez(refer); return(p); } #endif /* def TRUST_FILES */ #ifdef PCRS /********************************************************************* * * Function : re_process_buffer * * Description : Apply all jobs from the joblist (aka. Perl regexp's) to * the text buffer that's been accumulated in csp->iob->buf * and set csp->content_length to the modified size. * * Parameters : * 1 : csp = Current client state (buffers, headers, etc...) * * Returns : a pointer to the (newly allocated) modified buffer. * * *********************************************************************/ char *re_process_buffer(struct client_state *csp) { int hits=0; int size = csp->iob->eod - csp->iob->cur; char *old=csp->iob->cur, *new = NULL; pcrs_job *job, *joblist; struct file_list *fl; struct re_filterfile_spec *b; /* Sanity first ;-) */ if (size <= 0) { return(strdup("")); } if ( ( NULL == (fl = csp->rlist) ) || ( NULL == (b = fl->f) ) ) { log_error(LOG_LEVEL_ERROR, "Unable to get current state of regexp filtering."); return(strdup("")); } joblist = b->joblist; log_error(LOG_LEVEL_RE_FILTER, "re_filtering %s%s (size %d) ...", csp->http->hostport, csp->http->path, size); /* Apply all jobs from the joblist */ for (job = joblist; NULL != job; job = job->next) { hits += pcrs_exec_substitution(job, old, size, &new, &size); if (old != csp->iob->cur) free(old); old=new; } log_error(LOG_LEVEL_RE_FILTER, " produced %d hits (new size %d).", hits, size); csp->content_length = size; /* fwiw, reset the iob */ IOB_RESET(csp); return(new); } #endif /* def PCRS */ /********************************************************************* * * Function : url_actions * * Description : Gets the actions for this URL. * * Parameters : * 1 : http = http_request request for blocked URLs * 2 : csp = Current client state (buffers, headers, etc...) * * Returns : N/A * *********************************************************************/ void url_actions(struct http_request *http, struct client_state *csp) { struct file_list *fl; struct url_actions *b; init_current_action(csp->action); if (((fl = csp->actions_list) == NULL) || ((b = fl->f) == NULL)) { return; } apply_url_actions(csp->action, http, b); } /********************************************************************* * * Function : apply_url_actions * * Description : Applies a list of URL actions. * * Parameters : * 1 : action = Destination. * 2 : http = Current URL * 3 : b = list of URL actions to apply * * Returns : N/A * *********************************************************************/ void apply_url_actions(struct current_action_spec *action, struct http_request *http, struct url_actions *b) { struct url_spec url[1]; if (b == NULL) { /* Should never happen */ return; } *url = dsplit(http->host); /* if splitting the domain fails, punt */ if (url->dbuf == NULL) { return; } for (b = b->next; NULL != b; b = b->next) { if ((b->url->port == 0) || (b->url->port == http->port)) { if ((b->url->domain[0] == '\0') || (domaincmp(b->url, url) == 0)) { if ((b->url->path == NULL) || #ifdef REGEX (regexec(b->url->preg, http->path, 0, NULL, 0) == 0) #else (strncmp(b->url->path, http->path, b->url->pathlen) == 0) #endif ) { merge_current_action(action, b->action); } } } } freez(url->dbuf); freez(url->dvec); } /********************************************************************* * * Function : forward_url * * Description : Should we forward this to another proxy? * * Parameters : * 1 : http = http_request request for current URL * 2 : csp = Current client state (buffers, headers, etc...) * * Returns : Return gw_default for no forward match, * else a gateway pointer to a specific forwarding proxy. * *********************************************************************/ const struct gateway *forward_url(struct http_request *http, struct client_state *csp) { struct file_list *fl; struct forward_spec *b; struct url_spec url[1]; if (((fl = csp->flist) == NULL) || ((b = fl->f) == NULL)) { return(gw_default); } *url = dsplit(http->host); /* if splitting the domain fails, punt */ if (url->dbuf == NULL) return(gw_default); for (b = b->next; b ; b = b->next) { if ((b->url->port == 0) || (b->url->port == http->port)) { if ((b->url->domain[0] == '\0') || (domaincmp(b->url, url) == 0)) { if ((b->url->path == NULL) || #ifdef REGEX (regexec(b->url->preg, http->path, 0, NULL, 0) == 0) #else (strncmp(b->url->path, http->path, b->url->pathlen) == 0) #endif ) { freez(url->dbuf); freez(url->dvec); return(b->gw); } } } } freez(url->dbuf); freez(url->dvec); return(gw_default); } /********************************************************************* * * Function : dsplit * * Description : Takes a domain and returns a pointer to a url_spec * structure populated with dbuf, dcnt and dvec. The * other fields in the structure that is returned are zero. * * Parameters : * 1 : domain = a URL address * * Returns : url_spec structure populated with dbuf, dcnt and dvec. * *********************************************************************/ struct url_spec dsplit(char *domain) { struct url_spec ret[1]; char *v[BUFSIZ]; int size; char *p; memset(ret, '\0', sizeof(*ret)); if (domain[strlen(domain) - 1] == '.') { ret->unanchored |= ANCHOR_RIGHT; } if (domain[0] == '.') { ret->unanchored |= ANCHOR_LEFT; } ret->dbuf = strdup(domain); /* map to lower case */ for (p = ret->dbuf; *p ; p++) *p = tolower(*p); /* split the domain name into components */ ret->dcnt = ssplit(ret->dbuf, ".", v, SZ(v), 1, 1); if (ret->dcnt <= 0) { memset(ret, '\0', sizeof(ret)); return(*ret); } /* save a copy of the pointers in dvec */ size = ret->dcnt * sizeof(*ret->dvec); if ((ret->dvec = (char **)malloc(size))) { memcpy(ret->dvec, v, size); } return(*ret); } /********************************************************************* * * Function : domaincmp * * Description : Domain-wise Compare fqdn's. Governed by the bimap in * pattern->unachored, the comparison is un-, left-, * right-anchored, or both. * The individual domain names are compared with * trivialmatch(). * * Parameters : * 1 : pattern = a domain that may contain a '*' as a wildcard. * 2 : fqdn = domain name against which the patterns are compared. * * Returns : 0 => domains are equivalent, else no match. * *********************************************************************/ int domaincmp(struct url_spec *pattern, struct url_spec *fqdn) { char **pv, **fv; /* vectors */ int pn, fn; /* counters */ char *p, *f; /* chars */ pv = pattern->dvec; fv = fqdn->dvec; fn = pn = 0; while (fn < fqdn->dcnt && pn < pattern->dcnt) { p = pv[pn]; f = fv[fn]; if (simplematch(p, f)) { if(pn || !(pattern->unanchored & ANCHOR_LEFT)) { return 1; } } else { pn++; } fn++; } return ((pn < pattern->dcnt) || ((fn < fqdn->dcnt) && !(pattern->unanchored & ANCHOR_RIGHT))); } /* Local Variables: tab-width: 3 end: */