const char filters_rcs[] = "$Id: filters.c,v 1.110 2008/11/10 16:40:25 fabiankeil 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', `domain_split', * `filter_popups', `forward_url', 'redirect_url', * `ij_untrusted_url', `intercept_url', `pcrs_filter_respose', * `ijb_send_banner', `trust_url', `gif_deanimate_response', * `execute_single_pcrs_command', `rewrite_url', * `get_last_url' * * Copyright : Written by and Copyright (C) 2001, 2004-2008 the SourceForge * Privoxy team. http://www.privoxy.org/ * * 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 1.110 2008/11/10 16:40:25 fabiankeil * Fix a gcc44 warning. * * Revision 1.109 2008/11/08 15:48:41 fabiankeil * Mention actual values when complaining about * the chunk size exceeding the buffer size. * * Revision 1.108 2008/05/21 15:35:08 fabiankeil * - Mark csp as immutable for block_acl(). * - Remove an obsolete complaint about filter_popups(). * * Revision 1.107 2008/05/04 17:52:56 fabiankeil * Adjust parse_http_url() call to new prototype. * * Revision 1.106 2008/05/03 16:40:44 fabiankeil * Change content_filters_enabled()'s parameter from * csp->action to action so it can be also used in the * CGI code. Don't bother checking if there are filters * loaded, as that's somewhat besides the point. * * Revision 1.105 2008/03/28 15:13:39 fabiankeil * Remove inspect-jpegs action. * * Revision 1.104 2008/03/27 18:27:24 fabiankeil * Remove kill-popups action. * * Revision 1.103 2008/03/06 16:33:45 fabiankeil * If limit-connect isn't used, don't limit CONNECT requests to port 443. * * Revision 1.102 2008/03/01 14:00:44 fabiankeil * Let the block action take the reason for the block * as argument and show it on the "blocked" page. * * Revision 1.101 2008/02/23 16:57:12 fabiankeil * Rename url_actions() to get_url_actions() and let it * use the standard parameter ordering. * * Revision 1.100 2008/02/23 16:33:43 fabiankeil * Let forward_url() use the standard parameter ordering * and mark its second parameter immutable. * * Revision 1.99 2008/02/03 13:57:58 fabiankeil * Add SOCKS5 support for forward-override{}. * * Revision 1.98 2008/01/04 17:43:45 fabiankeil * Improve the warning messages that get logged if the action files * "enable" filters but no filters of that type have been loaded. * * Revision 1.97 2007/11/30 15:37:03 fabiankeil * Use freez instead of free. * * Revision 1.96 2007/10/19 16:53:28 fabiankeil * Add helper function to check if any content filters are enabled. * * Revision 1.95 2007/10/17 19:31:20 fabiankeil * Omitting the zero chunk that ends the chunk transfer encoding seems * to be the new black. Log the problem and continue filtering anyway. * * Revision 1.94 2007/09/29 13:20:20 fabiankeil * Remove two redundant and one useless log messages. * * Revision 1.93 2007/09/29 10:21:16 fabiankeil * - Move get_filter_function() from jcc.c to filters.c * so the filter functions can be static. * - Don't bother filtering body-less responses. * * Revision 1.92 2007/09/28 16:38:55 fabiankeil * - Execute content filters through execute_content_filter(). * - Add prepare_for_filtering() so filter functions don't have to * care about de-chunking and decompression. As a side effect this enables * decompression for gif_deanimate_response() and jpeg_inspect_response(). * - Change remove_chunked_transfer_coding()'s return type to jb_err. * Some clowns feel like chunking empty responses in which case * (size == 0) is valid but previously would be interpreted as error. * * Revision 1.91 2007/09/02 15:31:20 fabiankeil * Move match_portlist() from filter.c to urlmatch.c. * It's used for url matching, not for filtering. * * Revision 1.90 2007/09/02 12:44:17 fabiankeil * Remove newline at the end of a log_error() message. * * Revision 1.89 2007/08/05 13:42:23 fabiankeil * #1763173 from Stefan Huehner: declare some more functions static. * * Revision 1.88 2007/06/01 16:41:11 fabiankeil * Add forward-override{} to change the forwarding settings through * action sections. This is mainly interesting to forward different * clients differently (for example based on User-Agent or request * origin). * * Revision 1.87 2007/04/30 15:53:10 fabiankeil * Make sure filters with dynamic jobs actually use them. * * Revision 1.86 2007/04/30 15:03:28 fabiankeil * - Introduce dynamic pcrs jobs that can resolve variables. * - Don't run redirect functions more than once, * unless they are activated more than once. * * Revision 1.85 2007/03/21 12:24:47 fabiankeil * - Log the content size after decompression in decompress_iob() * instead of pcrs_filter_response(). * * Revision 1.84 2007/03/20 15:16:34 fabiankeil * Use dedicated header filter actions instead of abusing "filter". * Replace "filter-client-headers" and "filter-client-headers" * with "server-header-filter" and "client-header-filter". * * Revision 1.83 2007/03/17 15:20:05 fabiankeil * New config option: enforce-blocks. * * Revision 1.82 2007/03/13 11:28:43 fabiankeil * - Fix port handling in acl_addr() and use a temporary acl spec * copy so error messages don't contain a truncated version. * - Log size of iob before and after decompression. * * Revision 1.81 2007/03/05 14:40:53 fabiankeil * - Cosmetical changes for LOG_LEVEL_RE_FILTER messages. * - Hide the "Go there anyway" link for blocked CONNECT * requests where going there anyway doesn't work anyway. * * Revision 1.80 2007/02/07 10:55:20 fabiankeil * - Save the reason for generating http_responses. * - Block (+block) with status code 403 instead of 404. * - Use a different kludge to remember a failed decompression. * * Revision 1.79 2007/01/31 16:21:38 fabiankeil * Search for Max-Forwards headers case-insensitive, * don't generate the "501 unsupported" message for invalid * Max-Forwards values and don't increase negative ones. * * Revision 1.78 2007/01/28 13:41:18 fabiankeil * - Add HEAD support to finish_http_response. * - Add error favicon to internal HTML error messages. * * Revision 1.77 2007/01/12 15:36:44 fabiankeil * Mark *csp as immutable for is_untrusted_url() * and is_imageurl(). Closes FR 1237736. * * Revision 1.76 2007/01/01 19:36:37 fabiankeil * Integrate a modified version of Wil Mahan's * zlib patch (PR #895531). * * Revision 1.75 2006/12/29 18:30:46 fabiankeil * Fixed gcc43 conversion warnings, * changed sprintf calls to snprintf. * * Revision 1.74 2006/12/24 17:37:38 fabiankeil * Adjust comment in pcrs_filter_response() * to recent pcrs changes. Hohoho. * * Revision 1.73 2006/12/23 16:01:02 fabiankeil * Don't crash if pcre returns an error code * that pcrs didn't expect. Fixes BR 1621173. * * Revision 1.72 2006/12/22 18:52:53 fabiankeil * Modified is_untrusted_url to complain in case of * write errors and to give a reason when adding new * entries to the trustfile. Closes FR 1097611. * * Revision 1.71 2006/12/22 14:24:52 fabiankeil * Skip empty filter files in pcrs_filter_response, * but don't ignore the ones that come afterwards. * Fixes parts of BR 1619208. * * Revision 1.70 2006/12/09 13:33:15 fabiankeil * Added some sanity checks for get_last_url(). * Fixed possible segfault caused by my last commit. * * Revision 1.69 2006/12/08 12:39:13 fabiankeil * Let get_last_url() catch https URLs as well. * * Revision 1.68 2006/12/05 14:45:48 fabiankeil * Make sure get_last_url() behaves like advertised * and fast-redirects{} can be combined with redirect{}. * * Revision 1.67 2006/11/28 15:19:43 fabiankeil * Implemented +redirect{s@foo@bar@} to generate * a redirect based on a rewritten version of the * original URL. * * Revision 1.66 2006/09/23 13:26:38 roro * Replace TABs by spaces in source code. * * Revision 1.65 2006/09/21 12:54:43 fabiankeil * Fix +redirect{}. Didn't work with -fast-redirects. * * Revision 1.64 2006/08/31 10:55:49 fabiankeil * Block requests for untrusted URLs with status * code 403 instead of 200. * * Revision 1.63 2006/08/31 10:11:28 fabiankeil * Don't free p which is still in use and will be later * freed by free_map(). Don't claim the referrer is unknown * when the client didn't set one. * * Revision 1.62 2006/08/14 00:27:47 david__schmidt * Feature request 595948: Re-Filter logging in single line * * Revision 1.61 2006/08/03 02:46:41 david__schmidt * Incorporate Fabian Keil's patch work: http://www.fabiankeil.de/sourcecode/privoxy/ * * Revision 1.60 2006/07/18 14:48:46 david__schmidt * Reorganizing the repository: swapping out what was HEAD (the old 3.1 branch) * with what was really the latest development (the v_3_0_branch branch) * * Revision 1.58.2.9 2006/01/29 23:10:56 david__schmidt * Multiple filter file support * * Revision 1.58.2.8 2005/05/07 21:50:55 david__schmidt * A few memory leaks plugged (mostly on error paths) * * Revision 1.58.2.7 2004/10/03 12:53:32 david__schmidt * Add the ability to check jpeg images for invalid * lengths of comment blocks. Defensive strategy * against the exploit: * Microsoft Security Bulletin MS04-028 * Buffer Overrun in JPEG Processing (GDI+) Could * Allow Code Execution (833987) * Enabled with +inspect-jpegs in actions files. * * Revision 1.58.2.6 2003/12/06 22:18:27 gliptak * Correcting compile problem with FEATURE_IMAGE_BLOCKING * * Revision 1.58.2.5 2003/11/11 13:10:31 oes * Fixed bug #839859: "See why" link URL now gets url-encoded. * * Revision 1.58.2.4 2003/02/28 12:52:45 oes * Fixed a typo * * Revision 1.58.2.3 2002/09/25 14:51:51 oes * Added basic support for OPTIONS and TRACE HTTP methods: * New function direct_response which handles OPTIONS and * TRACE requests whose Max-Forwards header field is zero. * * Revision 1.58.2.2 2002/08/01 17:18:28 oes * Fixed BR 537651 / SR 579724 (MSIE image detect improper for IE/Mac) * * Revision 1.58.2.1 2002/07/26 15:18:53 oes * - Bugfix: Executing a filters without jobs no longer results in * turing off *all* filters. * - Security fix: Malicious web servers can't cause a seg fault * through bogus chunk sizes anymore * * Revision 1.58 2002/04/24 02:11:17 oes * Jon's multiple AF patch: url_actions now evaluates rules * from all AFs. * * Revision 1.57 2002/04/08 20:38:34 swa * fixed JB spelling * * Revision 1.56 2002/04/05 15:51:24 oes * - bugfix: error-pages now get correct request protocol * - fix for invalid HTML in trust info * * Revision 1.55 2002/04/02 16:13:51 oes * Fix: No "Go there anyway" for SSL * * Revision 1.54 2002/04/02 14:55:56 oes * Bugfix: is_untrusted_url() now depends on FEATURE_TRUST, not FEATURE_COOKIE_JAR * * Revision 1.53 2002/03/26 22:29:54 swa * we have a new homepage! * * Revision 1.52 2002/03/24 16:35:57 jongfoster * Removing logo * * Revision 1.51 2002/03/24 15:23:33 jongfoster * Name changes * * Revision 1.50 2002/03/24 13:25:43 swa * name change related issues * * Revision 1.49 2002/03/16 20:29:14 oes * Cosmetics * * Revision 1.48 2002/03/13 20:25:34 oes * Better logging for content filters * * Revision 1.47 2002/03/13 00:30:52 jongfoster * Killing warnings * Added option of always sending redirect for imageblock, * currently disabled with #if 0. * * Revision 1.46 2002/03/12 01:42:49 oes * Introduced modular filters * * Revision 1.45 2002/03/08 16:47:50 oes * Added choice beween GIF and PNG built-in images * * Revision 1.44 2002/03/07 03:49:31 oes * - Fixed compiler warnings etc * - Changed built-in images from GIF to PNG * (with regard to Unisys patent issue) * - Added a 4x4 pattern PNG which is less intrusive * than the logo but also clearly marks the deleted banners * * Revision 1.43 2002/01/22 23:51:59 jongfoster * Replacing strsav() with the safer string_append(). * * Adding missing html_encode() to error message generators. Where encoded * and unencoded versions of a string were provided, removing the unencoded * one. * * Revision 1.42 2002/01/17 21:00:32 jongfoster * Moving all our URL and URL pattern parsing code to urlmatch.c. * * Using a single, simple url_match(pattern,url) function - rather than * the 3-line match routine which was repeated all over the place. * * Renaming free_url to free_url_spec, since it frees a struct url_spec. * * Using parse_http_url() to parse URLs without faking a HTTP * request line for parse_http_request(). * * Revision 1.41 2001/11/13 00:14:07 jongfoster * Fixing stupid bug now I've figured out what || means. * (It always returns 0 or 1, not one of it's paramaters.) * * Revision 1.40 2001/10/26 17:37:55 oes * - Re-enabled Netscape 200/404 bug workaround in block_url(): * - Removed OS/2 special case * - Made block_url() independant from sed() having been run * - Made trust_url independant from sed() having been run * - Made is_imageurl independant from sed() having been run. * It now checks User-Agent: and Accept: by itself. * * * Revision 1.39 2001/10/25 03:40:48 david__schmidt * Change in porting tactics: OS/2's EMX porting layer doesn't allow multiple * threads to call select() simultaneously. So, it's time to do a real, live, * native OS/2 port. See defines for __EMX__ (the porting layer) vs. __OS2__ * (native). Both versions will work, but using __OS2__ offers multi-threading. * * Revision 1.38 2001/10/23 21:32:33 jongfoster * Adding error-checking to selected functions * * Revision 1.37 2001/10/22 15:33:56 david__schmidt * Special-cased OS/2 out of the Netscape-abort-on-404-in-js problem in * filters.c. Added a FIXME in front of the offending code. I'll gladly * put in a better/more robust fix for all parties if one is presented... * It seems that just returning 200 instead of 404 would pretty much fix * it for everyone, but I don't know all the history of the problem. * * Revision 1.36 2001/10/10 16:44:16 oes * Added match_portlist function * * Revision 1.35 2001/10/07 15:41:23 oes * Replaced 6 boolean members of csp with one bitmap (csp->flags) * * New function remove_chunked_transfer_coding that strips chunked * transfer coding to plain and is called by pcrs_filter_response * and gif_deanimate_response if neccessary * * Improved handling of zero-change re_filter runs * * pcrs_filter_response and gif_deanimate_response now remove * chunked transfer codeing before processing the body. * * Revision 1.34 2001/09/20 15:49:36 steudten * * Fix BUG: Change int size to size_t size in pcrs_filter_response(). * See cgi.c fill_template(). * * Revision 1.33 2001/09/16 17:05:14 jongfoster * Removing unused #include showarg.h * * Revision 1.32 2001/09/16 13:21:27 jongfoster * Changes to use new list functions. * * Revision 1.31 2001/09/16 11:38:02 jongfoster * Splitting fill_template() into 2 functions: * template_load() loads the file * template_fill() performs the PCRS regexps. * This is because the CGI edit interface has a "table row" * template which is used many times in the page - this * change means it's only loaded from disk once. * * Revision 1.30 2001/09/16 11:00:10 jongfoster * New function alloc_http_response, for symmetry with free_http_response * * Revision 1.29 2001/09/13 23:32:40 jongfoster * Moving image data to cgi.c rather than cgi.h * Fixing a GPF under Win32 (and any other OS that protects global * constants from being written to). * * Revision 1.28 2001/09/10 10:18:51 oes * Silenced compiler warnings * * Revision 1.27 2001/08/05 16:06:20 jongfoster * Modifiying "struct map" so that there are now separate header and * "map_entry" structures. This means that functions which modify a * map no longer need to return a pointer to the modified map. * Also, it no longer reverses the order of the entries (which may be * important with some advanced template substitutions). * * Revision 1.26 2001/07/30 22:08:36 jongfoster * Tidying up #defines: * - All feature #defines are now of the form FEATURE_xxx * - Permanently turned off WIN_GUI_EDIT * - Permanently turned on WEBDAV and SPLIT_PROXY_ARGS * * Revision 1.25 2001/07/26 10:09:46 oes * Made browser detection a little less naive * * Revision 1.24 2001/07/25 17:22:51 oes * Added workaround for Netscape bug that prevents display of page when loading a component fails. * * Revision 1.23 2001/07/23 13:40:12 oes * Fixed bug that caused document body to be dropped when pcrs joblist was empty. * * Revision 1.22 2001/07/18 12:29:34 oes * - Made gif_deanimate_response respect * csp->action->string[ACTION_STRING_DEANIMATE] * - Logging cosmetics * * Revision 1.21 2001/07/13 13:59:53 oes * - Introduced gif_deanimate_response which shares the * generic content modification interface of pcrs_filter_response * and acts as a wrapper to deanimate.c:gif_deanimate() * - Renamed re_process_buffer to pcrs_filter_response * - pcrs_filter_response now returns NULL on failiure * - Removed all #ifdef PCRS * * Revision 1.20 2001/07/01 17:01:04 oes * Added comments and missing return statement in is_untrusted_url() * * Revision 1.19 2001/06/29 21:45:41 oes * Indentation, CRLF->LF, Tab-> Space * * Revision 1.18 2001/06/29 13:27:38 oes * - Cleaned up, renamed and reorderd functions * and improved comments * * - block_url: * - Ported to CGI platform. Now delivers * http_response or NULL * - Unified HTML and GIF generation (moved image detection * and GIF generation here from jcc.c:chat()) * - Fixed HTTP status to: * - 403 (Forbidden) for the "blocked" HTML message * - 200 (OK) for GIF answers * - 302 (Redirect) for redirect to GIF * * - trust_url: * - Ported to CGI platform. Now delivers * http_response or NULL * - Separated detection of untrusted URL into * (bool)is_untrusted_url * - Added enforcement of untrusted requests * * - Moved redirect_url() from cgi.c to here * and ported it to the CGI platform * * - Removed logentry from cancelled commit * * Revision 1.17 2001/06/09 10:55:28 jongfoster * Changing BUFSIZ ==> BUFFER_SIZE * * Revision 1.16 2001/06/07 23:10:26 jongfoster * Allowing unanchored domain patterns to back off and retry * if they partially match. Optimized right-anchored patterns. * Moving ACL and forward files into config file. * Replacing struct gateway with struct forward_spec * * Revision 1.15 2001/06/03 19:12:00 oes * extracted-CGI relevant stuff * * 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 #include #ifndef _WIN32 #ifndef __OS2__ #include #endif /* ndef __OS2__ */ #include #else #include #endif /* ndef _WIN32 */ #ifdef __OS2__ #include #endif /* def __OS2__ */ #include "project.h" #include "filters.h" #include "encode.h" #include "parsers.h" #include "ssplit.h" #include "errlog.h" #include "jbsockets.h" #include "miscutil.h" #include "actions.h" #include "cgi.h" #include "list.h" #include "deanimate.h" #include "urlmatch.h" #include "loaders.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)) static jb_err remove_chunked_transfer_coding(char *buffer, size_t *size); static jb_err prepare_for_filtering(struct client_state *csp); #ifdef FEATURE_ACL /********************************************************************* * * 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(const struct access_control_addr *dst, const struct client_state *csp) { struct access_control_list *acl = csp->config->acl; /* if not using an access control list, then permit the connection */ if (acl == NULL) { return(0); } /* search the list */ while (acl != NULL) { if ((csp->ip_addr_long & acl->src->mask) == acl->src->addr) { if (dst == NULL) { /* Just want to check if they have any access */ if (acl->action == ACL_PERMIT) { return(0); } } else if ( ((dst->addr & acl->dst->mask) == acl->dst->addr) && ((dst->port == acl->dst->port) || (acl->dst->port == 0))) { if (acl->action == ACL_PERMIT) { return(0); } else { return(1); } } } acl = acl->next; } return(1); } /********************************************************************* * * Function : acl_addr * * Description : Called from `load_config' 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(const char *aspec, struct access_control_addr *aca) { int i, masklength; long port; char *p; char *acl_spec = NULL; masklength = 32; port = 0; /* * Use a temporary acl spec copy so we can log * the unmodified original in case of parse errors. */ acl_spec = strdup(aspec); if (acl_spec == NULL) { /* XXX: This will be logged as parse error. */ return(-1); } if ((p = strchr(acl_spec, '/')) != NULL) { *p++ = '\0'; if (ijb_isdigit(*p) == 0) { freez(acl_spec); return(-1); } masklength = atoi(p); } if ((masklength < 0) || (masklength > 32)) { freez(acl_spec); return(-1); } if ((p = strchr(acl_spec, ':')) != NULL) { char *endptr; *p++ = '\0'; port = strtol(p, &endptr, 10); if (port <= 0 || port > 65535 || *endptr != '\0') { freez(acl_spec); return(-1); } } aca->port = (unsigned long)port; aca->addr = ntohl(resolve_hostname_to_ip(acl_spec)); freez(acl_spec); if (aca->addr == INADDR_NONE) { /* XXX: This will be logged as parse error. */ return(-1); } /* build the netmask */ aca->mask = 0; for (i=1; i <= masklength ; i++) { aca->mask |= (1U << (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 FEATURE_ACL */ /********************************************************************* * * Function : connect_port_is_forbidden * * Description : Check to see if CONNECT requests to the destination * port of this request are forbidden. The check is * independend of the actual request method. * * Parameters : * 1 : csp = Current client state (buffers, headers, etc...) * * Returns : True if yes, false otherwise. * *********************************************************************/ int connect_port_is_forbidden(const struct client_state *csp) { return ((csp->action->flags & ACTION_LIMIT_CONNECT) && !match_portlist(csp->action->string[ACTION_STRING_LIMIT_CONNECT], csp->http->port)); } /********************************************************************* * * Function : block_url * * Description : Called from `chat'. Check to see if we need to block this. * * Parameters : * 1 : csp = Current client state (buffers, headers, etc...) * * Returns : NULL => unblocked, else HTTP block response * *********************************************************************/ struct http_response *block_url(struct client_state *csp) { struct http_response *rsp; const char *new_content_type = NULL; /* * If it's not blocked, don't block it ;-) */ if ((csp->action->flags & ACTION_BLOCK) == 0) { return NULL; } if (csp->action->flags & ACTION_REDIRECT) { log_error(LOG_LEVEL_ERROR, "redirect{} overruled by block."); } /* * Else, prepare a response */ if (NULL == (rsp = alloc_http_response())) { return cgi_error_memory(); } /* * If it's an image-url, send back an image or redirect * as specified by the relevant +image action */ #ifdef FEATURE_IMAGE_BLOCKING if (((csp->action->flags & ACTION_IMAGE_BLOCKER) != 0) && is_imageurl(csp)) { char *p; /* determine HOW images should be blocked */ p = csp->action->string[ACTION_STRING_IMAGE_BLOCKER]; if(csp->action->flags & ACTION_HANDLE_AS_EMPTY_DOCUMENT) { log_error(LOG_LEVEL_ERROR, "handle-as-empty-document overruled by handle-as-image."); } #if 1 /* Two alternative strategies, use this one for now: */ /* and handle accordingly: */ if ((p == NULL) || (0 == strcmpic(p, "pattern"))) { rsp->status = strdup("403 Request blocked by Privoxy"); if (rsp->status == NULL) { free_http_response(rsp); return cgi_error_memory(); } rsp->body = bindup(image_pattern_data, image_pattern_length); if (rsp->body == NULL) { free_http_response(rsp); return cgi_error_memory(); } rsp->content_length = image_pattern_length; if (enlist_unique_header(rsp->headers, "Content-Type", BUILTIN_IMAGE_MIMETYPE)) { free_http_response(rsp); return cgi_error_memory(); } } else if (0 == strcmpic(p, "blank")) { rsp->status = strdup("403 Request blocked by Privoxy"); if (rsp->status == NULL) { free_http_response(rsp); return cgi_error_memory(); } rsp->body = bindup(image_blank_data, image_blank_length); if (rsp->body == NULL) { free_http_response(rsp); return cgi_error_memory(); } rsp->content_length = image_blank_length; if (enlist_unique_header(rsp->headers, "Content-Type", BUILTIN_IMAGE_MIMETYPE)) { free_http_response(rsp); return cgi_error_memory(); } } else { rsp->status = strdup("302 Local Redirect from Privoxy"); if (rsp->status == NULL) { free_http_response(rsp); return cgi_error_memory(); } if (enlist_unique_header(rsp->headers, "Location", p)) { free_http_response(rsp); return cgi_error_memory(); } } #else /* Following code is disabled for now */ /* and handle accordingly: */ if ((p == NULL) || (0 == strcmpic(p, "pattern"))) { p = CGI_PREFIX "send-banner?type=pattern"; } else if (0 == strcmpic(p, "blank")) { p = CGI_PREFIX "send-banner?type=blank"; } rsp->status = strdup("302 Local Redirect from Privoxy"); if (rsp->status == NULL) { free_http_response(rsp); return cgi_error_memory(); } if (enlist_unique_header(rsp->headers, "Location", p)) { free_http_response(rsp); return cgi_error_memory(); } #endif /* Preceeding code is disabled for now */ } else if(csp->action->flags & ACTION_HANDLE_AS_EMPTY_DOCUMENT) { /* * Send empty document. */ new_content_type = csp->action->string[ACTION_STRING_CONTENT_TYPE]; freez(rsp->body); rsp->body = strdup(" "); rsp->content_length = 1; rsp->status = strdup("403 Request blocked by Privoxy"); if (rsp->status == NULL) { free_http_response(rsp); return cgi_error_memory(); } if (new_content_type != 0) { log_error(LOG_LEVEL_HEADER, "Overwriting Content-Type with %s", new_content_type); if (enlist_unique_header(rsp->headers, "Content-Type", new_content_type)) { free_http_response(rsp); return cgi_error_memory(); } } } else #endif /* def FEATURE_IMAGE_BLOCKING */ /* * Else, generate an HTML "blocked" message: */ { jb_err err; struct map * exports; char *p; /* * Workaround for stupid Netscape bug which prevents * pages from being displayed if loading a referenced * JavaScript or style sheet fails. So make it appear * as if it succeeded. */ if ( NULL != (p = get_header_value(csp->headers, "User-Agent:")) && !strncmpic(p, "mozilla", 7) /* Catch Netscape but */ && !strstr(p, "Gecko") /* save Mozilla, */ && !strstr(p, "compatible") /* MSIE */ && !strstr(p, "Opera")) /* and Opera. */ { rsp->status = strdup("200 Request for blocked URL"); } else { rsp->status = strdup("403 Request for blocked URL"); } if (rsp->status == NULL) { free_http_response(rsp); return cgi_error_memory(); } exports = default_exports(csp, NULL); if (exports == NULL) { free_http_response(rsp); return cgi_error_memory(); } #ifdef FEATURE_FORCE_LOAD err = map(exports, "force-prefix", 1, FORCE_PREFIX, 1); /* * Export the force conditional block killer if * * - Privoxy was compiled without FEATURE_FORCE_LOAD, or * - Privoxy is configured to enforce blocks, or * - it's a CONNECT request and enforcing wouldn't work anyway. */ if ((csp->config->feature_flags & RUNTIME_FEATURE_ENFORCE_BLOCKS) || (0 == strcmpic(csp->http->gpc, "connect"))) #endif /* ndef FEATURE_FORCE_LOAD */ { err = map_block_killer(exports, "force-support"); } if (!err) err = map(exports, "protocol", 1, csp->http->ssl ? "https://" : "http://", 1); if (!err) err = map(exports, "hostport", 1, html_encode(csp->http->hostport), 0); if (!err) err = map(exports, "path", 1, html_encode(csp->http->path), 0); if (!err) err = map(exports, "path-ue", 1, url_encode(csp->http->path), 0); if (!err) { const char *block_reason; if (csp->action->string[ACTION_STRING_BLOCK] != NULL) { block_reason = csp->action->string[ACTION_STRING_BLOCK]; } else { assert(connect_port_is_forbidden(csp)); block_reason = "Forbidden CONNECT port."; } err = map(exports, "block-reason", 1, html_encode(block_reason), 0); } if (err) { free_map(exports); free_http_response(rsp); return cgi_error_memory(); } err = template_fill_for_cgi(csp, "blocked", exports, rsp); if (err) { free_http_response(rsp); return cgi_error_memory(); } } rsp->reason = RSP_REASON_BLOCKED; return finish_http_response(csp, rsp); } #ifdef FEATURE_TRUST /********************************************************************* * * Function : trust_url FIXME: I should be called distrust_url * * Description : Calls is_untrusted_url to determine if the URL is trusted * and if not, returns a HTTP 403 response with a reject message. * * Parameters : * 1 : csp = Current client state (buffers, headers, etc...) * * Returns : NULL => trusted, else http_response. * *********************************************************************/ struct http_response *trust_url(struct client_state *csp) { struct http_response *rsp; struct map * exports; char buf[BUFFER_SIZE]; char *p; struct url_spec **tl; struct url_spec *t; jb_err err; /* * Don't bother to work on trusted URLs */ if (!is_untrusted_url(csp)) { return NULL; } /* * Else, prepare a response: */ if (NULL == (rsp = alloc_http_response())) { return cgi_error_memory(); } rsp->status = strdup("403 Request blocked by Privoxy"); exports = default_exports(csp, NULL); if (exports == NULL || rsp->status == NULL) { free_http_response(rsp); return cgi_error_memory(); } /* * Export the protocol, host, port, and referrer information */ err = map(exports, "hostport", 1, csp->http->hostport, 1); if (!err) err = map(exports, "protocol", 1, csp->http->ssl ? "https://" : "http://", 1); if (!err) err = map(exports, "path", 1, csp->http->path, 1); if (NULL != (p = get_header_value(csp->headers, "Referer:"))) { if (!err) err = map(exports, "referrer", 1, html_encode(p), 0); } else { if (!err) err = map(exports, "referrer", 1, "none set", 1); } if (err) { free_map(exports); free_http_response(rsp); return cgi_error_memory(); } /* * Export the trust list */ p = strdup(""); for (tl = csp->config->trust_list; (t = *tl) != NULL ; tl++) { snprintf(buf, sizeof(buf), "
  • %s
  • \n", t->spec); string_append(&p, buf); } err = map(exports, "trusted-referrers", 1, p, 0); if (err) { free_map(exports); free_http_response(rsp); return cgi_error_memory(); } /* * Export the trust info, if available */ if (csp->config->trust_info->first) { struct list_entry *l; p = strdup(""); for (l = csp->config->trust_info->first; l ; l = l->next) { snprintf(buf, sizeof(buf), "
  • %s
    \n", l->str, l->str); string_append(&p, buf); } err = map(exports, "trust-info", 1, p, 0); } else { err = map_block_killer(exports, "have-trust-info"); } if (err) { free_map(exports); free_http_response(rsp); return cgi_error_memory(); } /* * Export the force conditional block killer if * * - Privoxy was compiled without FEATURE_FORCE_LOAD, or * - Privoxy is configured to enforce blocks, or * - it's a CONNECT request and enforcing wouldn't work anyway. */ #ifdef FEATURE_FORCE_LOAD if ((csp->config->feature_flags & RUNTIME_FEATURE_ENFORCE_BLOCKS) || (0 == strcmpic(csp->http->gpc, "connect"))) { err = map_block_killer(exports, "force-support"); } else { err = map(exports, "force-prefix", 1, FORCE_PREFIX, 1); } #else /* ifndef FEATURE_FORCE_LOAD */ err = map_block_killer(exports, "force-support"); #endif /* ndef FEATURE_FORCE_LOAD */ if (err) { free_map(exports); free_http_response(rsp); return cgi_error_memory(); } /* * Build the response */ err = template_fill_for_cgi(csp, "untrusted", exports, rsp); if (err) { free_http_response(rsp); return cgi_error_memory(); } rsp->reason = RSP_REASON_UNTRUSTED; return finish_http_response(csp, rsp); } #endif /* def FEATURE_TRUST */ /********************************************************************* * * Function : compile_dynamic_pcrs_job_list * * Description : Compiles a dynamic pcrs job list (one with variables * resolved at request time) * * Parameters : * 1 : csp = Current client state (buffers, headers, etc...) * 2 : b = The filter list to compile * * Returns : NULL in case of errors, otherwise the * pcrs job list. * *********************************************************************/ pcrs_job *compile_dynamic_pcrs_job_list(const struct client_state *csp, const struct re_filterfile_spec *b) { struct list_entry *pattern; pcrs_job *job_list = NULL; pcrs_job *dummy = NULL; pcrs_job *lastjob = NULL; int error = 0; const struct pcrs_variable variables[] = { {"url", csp->http->url, 1}, {"path", csp->http->path, 1}, {"host", csp->http->host, 1}, {"origin", csp->ip_addr_str, 1}, {NULL, NULL, 1} }; for (pattern = b->patterns->first; pattern != NULL; pattern = pattern->next) { assert(pattern->str != NULL); dummy = pcrs_compile_dynamic_command(pattern->str, variables, &error); if (NULL == dummy) { assert(error < 0); log_error(LOG_LEVEL_ERROR, "Adding filter job \'%s\' to dynamic filter %s failed: %s", pattern->str, b->name, pcrs_strerror(error)); continue; } else { if (error == PCRS_WARN_TRUNCATION) { log_error(LOG_LEVEL_ERROR, "At least one of the variables in \'%s\' had to " "be truncated before compilation", pattern->str); } if (job_list == NULL) { job_list = dummy; } else { lastjob->next = dummy; } lastjob = dummy; } } return job_list; } /********************************************************************* * * Function : rewrite_url * * Description : Rewrites a URL with a single pcrs command * and returns the result if it differs from the * original and isn't obviously invalid. * * Parameters : * 1 : old_url = URL to rewrite. * 2 : pcrs_command = pcrs command formatted as string (s@foo@bar@) * * * Returns : NULL if the pcrs_command didn't change the url, or * the result of the modification. * *********************************************************************/ char *rewrite_url(char *old_url, const char *pcrs_command) { char *new_url = NULL; int hits; assert(old_url); assert(pcrs_command); new_url = pcrs_execute_single_command(old_url, pcrs_command, &hits); if (hits == 0) { log_error(LOG_LEVEL_REDIRECTS, "pcrs command \"%s\" didn't change \"%s\".", pcrs_command, old_url); freez(new_url); } else if (hits < 0) { log_error(LOG_LEVEL_REDIRECTS, "executing pcrs command \"%s\" to rewrite %s failed: %s", pcrs_command, old_url, pcrs_strerror(hits)); freez(new_url); } else if (strncmpic(new_url, "http://", 7) && strncmpic(new_url, "https://", 8)) { log_error(LOG_LEVEL_ERROR, "pcrs command \"%s\" changed \"%s\" to \"%s\" (%u hi%s), " "but the result doesn't look like a valid URL and will be ignored.", pcrs_command, old_url, new_url, hits, (hits == 1) ? "t" : "ts"); freez(new_url); } else { log_error(LOG_LEVEL_REDIRECTS, "pcrs command \"%s\" changed \"%s\" to \"%s\" (%u hi%s).", pcrs_command, old_url, new_url, hits, (hits == 1) ? "t" : "ts"); } return new_url; } #ifdef FEATURE_FAST_REDIRECTS /********************************************************************* * * Function : get_last_url * * Description : Search for the last URL inside a string. * If the string already is a URL, it will * be the first URL found. * * Parameters : * 1 : subject = the string to check * 2 : redirect_mode = +fast-redirect{} mode * * Returns : NULL if no URL was found, or * the last URL found. * *********************************************************************/ char *get_last_url(char *subject, const char *redirect_mode) { char *new_url = NULL; char *tmp; assert(subject); assert(redirect_mode); subject = strdup(subject); if (subject == NULL) { log_error(LOG_LEVEL_ERROR, "Out of memory while searching for redirects."); return NULL; } if (0 == strcmpic(redirect_mode, "check-decoded-url")) { log_error(LOG_LEVEL_REDIRECTS, "Decoding \"%s\" if necessary.", subject); new_url = url_decode(subject); if (new_url != NULL) { freez(subject); subject = new_url; } else { log_error(LOG_LEVEL_ERROR, "Unable to decode \"%s\".", subject); } } log_error(LOG_LEVEL_REDIRECTS, "Checking \"%s\" for redirects.", subject); /* * Find the last URL encoded in the request */ tmp = subject; while ((tmp = strstr(tmp, "http://")) != NULL) { new_url = tmp++; } tmp = (new_url != NULL) ? new_url : subject; while ((tmp = strstr(tmp, "https://")) != NULL) { new_url = tmp++; } if ((new_url != NULL) && ( (new_url != subject) || (0 == strncmpic(subject, "http://", 7)) || (0 == strncmpic(subject, "https://", 8)) )) { /* * Return new URL if we found a redirect * or if the subject already was a URL. * * The second case makes sure that we can * chain get_last_url after another redirection check * (like rewrite_url) without losing earlier redirects. */ new_url = strdup(new_url); freez(subject); return new_url; } freez(subject); return NULL; } #endif /* def FEATURE_FAST_REDIRECTS */ /********************************************************************* * * Function : redirect_url * * Description : Checks if Privoxy should answer the request with * a HTTP redirect and generates the redirect if * necessary. * * Parameters : * 1 : csp = Current client state (buffers, headers, etc...) * * Returns : NULL if the request can pass, HTTP redirect otherwise. * *********************************************************************/ struct http_response *redirect_url(struct client_state *csp) { struct http_response *rsp; #ifdef FEATURE_FAST_REDIRECTS /* * XXX: Do we still need FEATURE_FAST_REDIRECTS * as compile-time option? The user can easily disable * it in his action file. */ char * redirect_mode; #endif /* def FEATURE_FAST_REDIRECTS */ char *old_url = NULL; char *new_url = NULL; char *redirection_string; if ((csp->action->flags & ACTION_REDIRECT)) { redirection_string = csp->action->string[ACTION_STRING_REDIRECT]; /* * If the redirection string begins with 's', * assume it's a pcrs command, otherwise treat it as * properly formatted URL and use it for the redirection * directly. * * According to RFC 2616 section 14.30 the URL * has to be absolute and if the user tries: * +redirect{shit/this/will/be/parsed/as/pcrs_command.html} * she would get undefined results anyway. * */ if (*redirection_string == 's') { old_url = csp->http->url; new_url = rewrite_url(old_url, redirection_string); } else { log_error(LOG_LEVEL_REDIRECTS, "No pcrs command recognized, assuming that \"%s\" is already properly formatted.", redirection_string); new_url = strdup(redirection_string); } } #ifdef FEATURE_FAST_REDIRECTS if ((csp->action->flags & ACTION_FAST_REDIRECTS)) { redirect_mode = csp->action->string[ACTION_STRING_FAST_REDIRECTS]; /* * If it exists, use the previously rewritten URL as input * otherwise just use the old path. */ old_url = (new_url != NULL) ? new_url : strdup(csp->http->path); new_url = get_last_url(old_url, redirect_mode); freez(old_url); } /* * Disable redirect checkers, so that they * will be only run more than once if the user * also enables them through tags. * * From a performance point of view * it doesn't matter, but the duplicated * log messages are annoying. */ csp->action->flags &= ~ACTION_FAST_REDIRECTS; #endif /* def FEATURE_FAST_REDIRECTS */ csp->action->flags &= ~ACTION_REDIRECT; /* Did any redirect action trigger? */ if (new_url) { if (0 == strcmpic(new_url, csp->http->url)) { log_error(LOG_LEVEL_ERROR, "New URL \"%s\" and old URL \"%s\" are the same. Redirection loop prevented.", csp->http->url, new_url); freez(new_url); } else { log_error(LOG_LEVEL_REDIRECTS, "New URL is: %s", new_url); if (NULL == (rsp = alloc_http_response())) { freez(new_url); return cgi_error_memory(); } if ( enlist_unique_header(rsp->headers, "Location", new_url) || (NULL == (rsp->status = strdup("302 Local Redirect from Privoxy"))) ) { freez(new_url); free_http_response(rsp); return cgi_error_memory(); } rsp->reason = RSP_REASON_REDIRECTED; freez(new_url); return finish_http_response(csp, rsp); } } /* Only reached if no redirect is required */ return NULL; } #ifdef FEATURE_IMAGE_BLOCKING /********************************************************************* * * Function : is_imageurl * * Description : Given a URL, decide whether it is an image or not, * using either the info from a previous +image action * or, #ifdef FEATURE_IMAGE_DETECT_MSIE, and the browser * is MSIE and not on a Mac, tell from the browser's accept * header. * * Parameters : * 1 : csp = Current client state (buffers, headers, etc...) * * Returns : True (nonzero) if URL is an image, false (0) * otherwise * *********************************************************************/ int is_imageurl(const struct client_state *csp) { #ifdef FEATURE_IMAGE_DETECT_MSIE char *tmp; tmp = get_header_value(csp->headers, "User-Agent:"); if (tmp && strstr(tmp, "MSIE") && !strstr(tmp, "Mac_")) { tmp = get_header_value(csp->headers, "Accept:"); if (tmp && strstr(tmp, "image/gif")) { /* Client will accept HTML. If this seems counterintuitive, * blame Microsoft. */ return(0); } else { return(1); } } #endif /* def FEATURE_IMAGE_DETECT_MSIE */ return ((csp->action->flags & ACTION_IMAGE) != 0); } #endif /* def FEATURE_IMAGE_BLOCKING */ #ifdef FEATURE_TRUST /********************************************************************* * * Function : is_untrusted_url * * Description : Should we "distrust" this URL (and block it)? * * Yes if it matches a line in the trustfile, or if the * referrer matches a line starting with "+" in the * trustfile. * No otherwise. * * Parameters : * 1 : csp = Current client state (buffers, headers, etc...) * * Returns : 0 => trusted, 1 => untrusted * *********************************************************************/ int is_untrusted_url(const struct client_state *csp) { struct file_list *fl; struct block_spec *b; struct url_spec **trusted_url; struct http_request rhttp[1]; const char * referer; jb_err err; /* * If we don't have a trustlist, we trust everybody */ if (((fl = csp->tlist) == NULL) || ((b = fl->f) == NULL)) { return 0; } memset(rhttp, '\0', sizeof(*rhttp)); /* * Do we trust the request URL itself? */ for (b = b->next; b ; b = b->next) { if (url_match(b->url, csp->http)) { return b->reject; } } if (NULL == (referer = get_header_value(csp->headers, "Referer:"))) { /* no referrer was supplied */ return 1; } /* * If not, do we maybe trust its referrer? */ err = parse_http_url(referer, rhttp, REQUIRE_PROTOCOL); if (err) { return 1; } for (trusted_url = csp->config->trust_list; *trusted_url != NULL; trusted_url++) { if (url_match(*trusted_url, rhttp)) { /* if the URL's referrer is from a trusted referrer, then * add the target spec to the trustfile as an unblocked * domain and return 0 (which means it's OK). */ FILE *fp; if (NULL != (fp = fopen(csp->config->trustfile, "a"))) { char * path; char * path_end; char * new_entry = strdup("~"); string_append(&new_entry, csp->http->hostport); path = csp->http->path; if ( (path[0] == '/') && (path[1] == '~') && ((path_end = strchr(path + 2, '/')) != NULL)) { /* since this path points into a user's home space * be sure to include this spec in the trustfile. */ int path_len = path_end - path; /* save offset */ path = strdup(path); /* Copy string */ if (path != NULL) { path_end = path + path_len; /* regenerate ptr to new buffer */ *(path_end + 1) = '\0'; /* Truncate path after '/' */ } string_join(&new_entry, path); } /* * Give a reason for generating this entry. */ string_append(&new_entry, " # Trusted referrer was: "); string_append(&new_entry, referer); if (new_entry != NULL) { if (-1 == fprintf(fp, "%s\n", new_entry)) { log_error(LOG_LEVEL_ERROR, "Failed to append \'%s\' to trustfile \'%s\': %E", new_entry, csp->config->trustfile); } freez(new_entry); } else { /* FIXME: No way to handle out-of memory, so mostly ignoring it */ log_error(LOG_LEVEL_ERROR, "Out of memory adding pattern to trust file"); } fclose(fp); } else { log_error(LOG_LEVEL_ERROR, "Failed to append new entry for \'%s\' to trustfile \'%s\': %E", csp->http->hostport, csp->config->trustfile); } return 0; } } return 1; } #endif /* def FEATURE_TRUST */ /********************************************************************* * * Function : pcrs_filter_response * * Description : Execute all text substitutions from all applying * +filter actions on the text buffer that's been * accumulated in csp->iob->buf. * * Parameters : * 1 : csp = Current client state (buffers, headers, etc...) * * Returns : a pointer to the (newly allocated) modified buffer. * or NULL if there were no hits or something went wrong * *********************************************************************/ static char *pcrs_filter_response(struct client_state *csp) { int hits=0; size_t size, prev_size; char *old = NULL; char *new = NULL; pcrs_job *job; struct file_list *fl; struct re_filterfile_spec *b; struct list_entry *filtername; int i, found_filters = 0; /* * Sanity first */ if (csp->iob->cur >= csp->iob->eod) { return(NULL); } /* * Need to check the set of re_filterfiles... */ for (i = 0; i < MAX_AF_FILES; i++) { fl = csp->rlist[i]; if (NULL != fl) { if (NULL != fl->f) { found_filters = 1; break; } } } if (0 == found_filters) { log_error(LOG_LEVEL_ERROR, "Inconsistent configuration: " "content filtering enabled, but no content filters available."); return(NULL); } size = (size_t)(csp->iob->eod - csp->iob->cur); old = csp->iob->cur; for (i = 0; i < MAX_AF_FILES; i++) { fl = csp->rlist[i]; if ((NULL == fl) || (NULL == fl->f)) { /* * Either there are no filter files * left, or this filter file just * contains no valid filters. * * Continue to be sure we don't miss * valid filter files that are chained * after empty or invalid ones. */ continue; } /* * For all applying +filter actions, look if a filter by that * name exists and if yes, execute it's pcrs_joblist on the * buffer. */ for (b = fl->f; b; b = b->next) { if (b->type != FT_CONTENT_FILTER) { /* Skip header filters */ continue; } for (filtername = csp->action->multi[ACTION_MULTI_FILTER]->first; filtername ; filtername = filtername->next) { if (strcmp(b->name, filtername->str) == 0) { int current_hits = 0; /* Number of hits caused by this filter */ int job_number = 0; /* Which job we're currently executing */ int job_hits = 0; /* How many hits the current job caused */ pcrs_job *joblist = b->joblist; if (b->dynamic) joblist = compile_dynamic_pcrs_job_list(csp, b); if (NULL == joblist) { log_error(LOG_LEVEL_RE_FILTER, "Filter %s has empty joblist. Nothing to do.", b->name); continue; } prev_size = size; /* Apply all jobs from the joblist */ for (job = joblist; NULL != job; job = job->next) { job_number++; job_hits = pcrs_execute(job, old, size, &new, &size); if (job_hits >= 0) { /* * That went well. Continue filtering * and use the result of this job as * input for the next one. */ current_hits += job_hits; if (old != csp->iob->cur) { freez(old); } old = new; } else { /* * This job caused an unexpected error. Inform the user * and skip the rest of the jobs in this filter. We could * continue with the next job, but usually the jobs * depend on each other or are similar enough to * fail for the same reason. * * At the moment our pcrs expects the error codes of pcre 3.4, * but newer pcre versions can return additional error codes. * As a result pcrs_strerror()'s error message might be * "Unknown error ...", therefore we print the numerical value * as well. * * XXX: Is this important enough for LOG_LEVEL_ERROR or * should we use LOG_LEVEL_RE_FILTER instead? */ log_error(LOG_LEVEL_ERROR, "Skipped filter \'%s\' after job number %u: %s (%d)", b->name, job_number, pcrs_strerror(job_hits), job_hits); break; } } if (b->dynamic) pcrs_free_joblist(joblist); log_error(LOG_LEVEL_RE_FILTER, "filtering %s%s (size %d) with \'%s\' produced %d hits (new size %d).", csp->http->hostport, csp->http->path, prev_size, b->name, current_hits, size); hits += current_hits; } } } } /* * If there were no hits, destroy our copy and let * chat() use the original in csp->iob */ if (!hits) { freez(new); return(NULL); } csp->flags |= CSP_FLAG_MODIFIED; csp->content_length = size; IOB_RESET(csp); return(new); } /********************************************************************* * * Function : gif_deanimate_response * * Description : Deanimate the GIF image that has been accumulated in * csp->iob->buf, set csp->content_length to the modified * size and raise the CSP_FLAG_MODIFIED flag. * * Parameters : * 1 : csp = Current client state (buffers, headers, etc...) * * Returns : a pointer to the (newly allocated) modified buffer. * or NULL in case something went wrong. * *********************************************************************/ static char *gif_deanimate_response(struct client_state *csp) { struct binbuffer *in, *out; char *p; size_t size; size = (size_t)(csp->iob->eod - csp->iob->cur); if ( (NULL == (in = (struct binbuffer *)zalloc(sizeof *in ))) || (NULL == (out = (struct binbuffer *)zalloc(sizeof *out))) ) { log_error(LOG_LEVEL_DEANIMATE, "failed! (no mem)"); return NULL; } in->buffer = csp->iob->cur; in->size = size; if (gif_deanimate(in, out, strncmp("last", csp->action->string[ACTION_STRING_DEANIMATE], 4))) { log_error(LOG_LEVEL_DEANIMATE, "failed! (gif parsing)"); freez(in); buf_free(out); return(NULL); } else { if ((int)size == out->offset) { log_error(LOG_LEVEL_DEANIMATE, "GIF not changed."); } else { log_error(LOG_LEVEL_DEANIMATE, "Success! GIF shrunk from %d bytes to %d.", size, out->offset); } csp->content_length = out->offset; csp->flags |= CSP_FLAG_MODIFIED; p = out->buffer; freez(in); freez(out); return(p); } } /********************************************************************* * * Function : get_filter_function * * Description : Decides which content filter function has * to be applied (if any). * * Parameters : * 1 : csp = Current client state (buffers, headers, etc...) * * Returns : The content filter function to run, or * NULL if no content filter is active * *********************************************************************/ filter_function_ptr get_filter_function(struct client_state *csp) { filter_function_ptr filter_function = NULL; /* * Are we enabling text mode by force? */ if (csp->action->flags & ACTION_FORCE_TEXT_MODE) { /* * Do we really have to? */ if (csp->content_type & CT_TEXT) { log_error(LOG_LEVEL_HEADER, "Text mode is already enabled."); } else { csp->content_type |= CT_TEXT; log_error(LOG_LEVEL_HEADER, "Text mode enabled by force. Take cover!"); } } if (!(csp->content_type & CT_DECLARED)) { /* * The server didn't bother to declare a MIME-Type. * Assume it's text that can be filtered. * * This also regulary happens with 304 responses, * therefore logging anything here would cause * too much noise. */ csp->content_type |= CT_TEXT; } /* * Choose the applying filter function based on * the content type and action settings. */ if ((csp->content_type & CT_TEXT) && (csp->rlist != NULL) && (!list_is_empty(csp->action->multi[ACTION_MULTI_FILTER]))) { filter_function = pcrs_filter_response; } else if ((csp->content_type & CT_GIF) && (csp->action->flags & ACTION_DEANIMATE)) { filter_function = gif_deanimate_response; } return filter_function; } /********************************************************************* * * Function : remove_chunked_transfer_coding * * Description : In-situ remove the "chunked" transfer coding as defined * in rfc2616 from a buffer. * * Parameters : * 1 : buffer = Pointer to the text buffer * 2 : size = In: Number of bytes to be processed, * Out: Number of bytes after de-chunking. * (undefined in case of errors) * * Returns : JB_ERR_OK for success, * JB_ERR_PARSE otherwise * *********************************************************************/ static jb_err remove_chunked_transfer_coding(char *buffer, size_t *size) { size_t newsize = 0; unsigned int chunksize = 0; char *from_p, *to_p; assert(buffer); from_p = to_p = buffer; if (sscanf(buffer, "%x", &chunksize) != 1) { log_error(LOG_LEVEL_ERROR, "Invalid first chunksize while stripping \"chunked\" transfer coding"); return JB_ERR_PARSE; } while (chunksize > 0U) { if (NULL == (from_p = strstr(from_p, "\r\n"))) { log_error(LOG_LEVEL_ERROR, "Parse error while stripping \"chunked\" transfer coding"); return JB_ERR_PARSE; } if ((newsize += chunksize) >= *size) { log_error(LOG_LEVEL_ERROR, "Chunk size %d exceeds buffer size %d in \"chunked\" transfer coding", chunksize, *size); return JB_ERR_PARSE; } from_p += 2; memmove(to_p, from_p, (size_t) chunksize); to_p = buffer + newsize; from_p += chunksize + 2; if (sscanf(from_p, "%x", &chunksize) != 1) { log_error(LOG_LEVEL_INFO, "Invalid \"chunked\" transfer encoding detected and ignored."); break; } } /* XXX: Should get its own loglevel. */ log_error(LOG_LEVEL_RE_FILTER, "De-chunking successful. Shrunk from %d to %d", *size, newsize); *size = newsize; return JB_ERR_OK; } /********************************************************************* * * Function : prepare_for_filtering * * Description : If necessary, de-chunks and decompresses * the content so it can get filterd. * * Parameters : * 1 : csp = Current client state (buffers, headers, etc...) * * Returns : JB_ERR_OK for success, * JB_ERR_PARSE otherwise * *********************************************************************/ static jb_err prepare_for_filtering(struct client_state *csp) { jb_err err = JB_ERR_OK; /* * If the body has a "chunked" transfer-encoding, * get rid of it, adjusting size and iob->eod */ if (csp->flags & CSP_FLAG_CHUNKED) { size_t size = (size_t)(csp->iob->eod - csp->iob->cur); log_error(LOG_LEVEL_RE_FILTER, "Need to de-chunk first"); err = remove_chunked_transfer_coding(csp->iob->cur, &size); if (JB_ERR_OK == err) { csp->iob->eod = csp->iob->cur + size; csp->flags |= CSP_FLAG_MODIFIED; } else { return JB_ERR_PARSE; } } #ifdef FEATURE_ZLIB /* * If the body has a supported transfer-encoding, * decompress it, adjusting size and iob->eod. */ if (csp->content_type & (CT_GZIP|CT_DEFLATE)) { if (0 == csp->iob->eod - csp->iob->cur) { /* Nothing left after de-chunking. */ return JB_ERR_OK; } err = decompress_iob(csp); if (JB_ERR_OK == err) { csp->flags |= CSP_FLAG_MODIFIED; csp->content_type &= ~CT_TABOO; } else { /* * Unset CT_GZIP and CT_DEFLATE to remember not * to modify the Content-Encoding header later. */ csp->content_type &= ~CT_GZIP; csp->content_type &= ~CT_DEFLATE; } } #endif return err; } /********************************************************************* * * Function : execute_content_filter * * Description : Executes a given content filter. * * Parameters : * 1 : csp = Current client state (buffers, headers, etc...) * 2 : content_filter = The filter function to execute * * Returns : Pointer to the modified buffer, or * NULL if filtering failed or wasn't necessary. * *********************************************************************/ char *execute_content_filter(struct client_state *csp, filter_function_ptr content_filter) { if (0 == csp->iob->eod - csp->iob->cur) { /* * No content (probably status code 301, 302 ...), * no filtering necessary. */ return NULL; } if (JB_ERR_OK != prepare_for_filtering(csp)) { /* * failed to de-chunk or decompress. */ return NULL; } if (0 == csp->iob->eod - csp->iob->cur) { /* * Clown alarm: chunked and/or compressed nothing delivered. */ return NULL; } return ((*content_filter)(csp)); } /********************************************************************* * * Function : get_url_actions * * Description : Gets the actions for this URL. * * Parameters : * 1 : csp = Current client state (buffers, headers, etc...) * 2 : http = http_request request for blocked URLs * * Returns : N/A * *********************************************************************/ void get_url_actions(struct client_state *csp, struct http_request *http) { struct file_list *fl; struct url_actions *b; int i; init_current_action(csp->action); for (i = 0; i < MAX_AF_FILES; i++) { if (((fl = csp->actions_list[i]) == NULL) || ((b = fl->f) == NULL)) { return; } apply_url_actions(csp->action, http, b); } return; } /********************************************************************* * * 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) { if (b == NULL) { /* Should never happen */ return; } for (b = b->next; NULL != b; b = b->next) { if (url_match(b->url, http)) { merge_current_action(action, b->action); } } } /********************************************************************* * * Function : get_forward_override_settings * * Description : Returns forward settings as specified with the * forward-override{} action. forward-override accepts * forward lines similar to the one used in the * configuration file, but without the URL pattern. * * For example: * * forward / . * * in the configuration file can be replaced with * the action section: * * {+forward-override{forward .}} * / * * Parameters : * 1 : csp = Current client state (buffers, headers, etc...) * * Returns : Pointer to forwarding structure in case of success. * Invalid syntax is fatal. * *********************************************************************/ const static struct forward_spec *get_forward_override_settings(struct client_state *csp) { const char *forward_override_line = csp->action->string[ACTION_STRING_FORWARD_OVERRIDE]; char forward_settings[BUFFER_SIZE]; char *http_parent = NULL; /* variable names were chosen for consistency reasons. */ struct forward_spec *fwd = NULL; int vec_count; char *vec[3]; assert(csp->action->flags & ACTION_FORWARD_OVERRIDE); /* Should be enforced by load_one_actions_file() */ assert(strlen(forward_override_line) < sizeof(forward_settings) - 1); /* Create a copy ssplit can modify */ strlcpy(forward_settings, forward_override_line, sizeof(forward_settings)); if (NULL != csp->fwd) { /* * XXX: Currently necessary to prevent memory * leaks when the show-url-info cgi page is visited. */ unload_forward_spec(csp->fwd); } /* * allocate a new forward node, valid only for * the lifetime of this request. Save its location * in csp as well, so sweep() can free it later on. */ fwd = csp->fwd = zalloc(sizeof(*fwd)); if (NULL == fwd) { log_error(LOG_LEVEL_FATAL, "can't allocate memory for forward-override{%s}", forward_override_line); /* Never get here - LOG_LEVEL_FATAL causes program exit */ } vec_count = ssplit(forward_settings, " \t", vec, SZ(vec), 1, 1); if ((vec_count == 2) && !strcasecmp(vec[0], "forward")) { fwd->type = SOCKS_NONE; /* Parse the parent HTTP proxy host:port */ http_parent = vec[1]; } else if (vec_count == 3) { char *socks_proxy = NULL; if (!strcasecmp(vec[0], "forward-socks4")) { fwd->type = SOCKS_4; socks_proxy = vec[1]; } else if (!strcasecmp(vec[0], "forward-socks4a")) { fwd->type = SOCKS_4A; socks_proxy = vec[1]; } else if (!strcasecmp(vec[0], "forward-socks5")) { fwd->type = SOCKS_5; socks_proxy = vec[1]; } if (NULL != socks_proxy) { /* Parse the SOCKS proxy host[:port] */ fwd->gateway_host = strdup(socks_proxy); if (NULL != (socks_proxy = strchr(fwd->gateway_host, ':'))) { *socks_proxy++ = '\0'; fwd->gateway_port = strtol(socks_proxy, NULL, 0); } if (fwd->gateway_port <= 0) { fwd->gateway_port = 1080; } http_parent = vec[2]; } } if (NULL == http_parent) { log_error(LOG_LEVEL_FATAL, "Invalid forward-override syntax in: %s", forward_override_line); /* Never get here - LOG_LEVEL_FATAL causes program exit */ } /* Parse http forwarding settings */ if (strcmp(http_parent, ".") != 0) { fwd->forward_host = strdup(http_parent); if (NULL != (http_parent = strchr(fwd->forward_host, ':'))) { *http_parent++ = '\0'; fwd->forward_port = strtol(http_parent, NULL, 0); } if (fwd->forward_port <= 0) { fwd->forward_port = 8000; } } assert (NULL != fwd); log_error(LOG_LEVEL_CONNECT, "Overriding forwarding settings based on \'%s\'", forward_override_line); return fwd; } /********************************************************************* * * Function : forward_url * * Description : Should we forward this to another proxy? * * Parameters : * 1 : csp = Current client state (buffers, headers, etc...) * 2 : http = http_request request for current URL * * Returns : Pointer to forwarding information. * *********************************************************************/ const struct forward_spec *forward_url(struct client_state *csp, const struct http_request *http) { static const struct forward_spec fwd_default[1] = { FORWARD_SPEC_INITIALIZER }; struct forward_spec *fwd = csp->config->forward; if (csp->action->flags & ACTION_FORWARD_OVERRIDE) { return get_forward_override_settings(csp); } if (fwd == NULL) { return fwd_default; } while (fwd != NULL) { if (url_match(fwd->url, http)) { return fwd; } fwd = fwd->next; } return fwd_default; } /********************************************************************* * * Function : direct_response * * Description : Check if Max-Forwards == 0 for an OPTIONS or TRACE * request and if so, return a HTTP 501 to the client. * * FIXME: I have a stupid name and I should handle the * requests properly. Still, what we do here is rfc- * compliant, whereas ignoring or forwarding are not. * * Parameters : * 1 : csp = Current client state (buffers, headers, etc...) * * Returns : http_response if , NULL if nonmatch or handler fail * *********************************************************************/ struct http_response *direct_response(struct client_state *csp) { struct http_response *rsp; struct list_entry *p; if ((0 == strcmpic(csp->http->gpc, "trace")) || (0 == strcmpic(csp->http->gpc, "options"))) { for (p = csp->headers->first; (p != NULL) ; p = p->next) { if (!strncmpic("Max-Forwards:", p->str, 13)) { unsigned int max_forwards; /* * If it's a Max-Forwards value of zero, * we have to intercept the request. */ if (1 == sscanf(p->str+12, ": %u", &max_forwards) && max_forwards == 0) { /* * FIXME: We could handle at least TRACE here, * but that would require a verbatim copy of * the request which we don't have anymore */ log_error(LOG_LEVEL_HEADER, "Detected header \'%s\' in OPTIONS or TRACE request. Returning 501.", p->str); /* Get mem for response or fail*/ if (NULL == (rsp = alloc_http_response())) { return cgi_error_memory(); } if (NULL == (rsp->status = strdup("501 Not Implemented"))) { free_http_response(rsp); return cgi_error_memory(); } rsp->is_static = 1; rsp->reason = RSP_REASON_UNSUPPORTED; return(finish_http_response(csp, rsp)); } } } } return NULL; } /********************************************************************* * * Function : content_filters_enabled * * Description : Checks whether there are any content filters * enabled for the current request. * * Parameters : * 1 : action = Action spec to check. * * Returns : TRUE for yes, FALSE otherwise * *********************************************************************/ int content_filters_enabled(const struct current_action_spec *action) { return ((action->flags & ACTION_DEANIMATE) || !list_is_empty(action->multi[ACTION_MULTI_FILTER])); } /* Local Variables: tab-width: 3 end: */