+ /*
+ * Else, prepare a response:
+ */
+ if (NULL == (rsp = alloc_http_response()))
+ {
+ return cgi_error_memory();
+ }
+
+ rsp->status = strdup_or_die("403 Request blocked by Privoxy");
+ exports = default_exports(csp, NULL);
+ if (exports == 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_or_die("");
+ for (tl = csp->config->trust_list; (t = *tl) != NULL ; tl++)
+ {
+ snprintf(buf, sizeof(buf), "<li>%s</li>\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_or_die("");
+ for (l = csp->config->trust_info->first; l ; l = l->next)
+ {
+ snprintf(buf, sizeof(buf), "<li> <a href=\"%s\">%s</a><br>\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->crunch_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},
+ {"listen-address", csp->listen_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)
+ {
+ log_error(LOG_LEVEL_ERROR,
+ "Compiling dynamic pcrs job '%s' for '%s' failed with error code %d: %s",
+ pattern->str, b->name, error, 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") && strchr(subject, '%'))
+ {
+ char *url_segment = NULL;
+ char **url_segments;
+ size_t max_segments;
+ int segments;
+
+ log_error(LOG_LEVEL_REDIRECTS,
+ "Checking \"%s\" for encoded redirects.", subject);
+
+ /*
+ * Check each parameter in the URL separately.
+ * Sectionize the URL at "?" and "&",
+ * go backwards through the segments, URL-decode them
+ * and look for a URL in the decoded result.
+ * Stop the search after the first match.
+ *
+ * XXX: This estimate is guaranteed to be high enough as we
+ * let ssplit() ignore empty fields, but also a bit wasteful.
+ */
+ max_segments = strlen(subject) / 2;
+ url_segments = malloc(max_segments * sizeof(char *));
+
+ if (NULL == url_segments)
+ {
+ log_error(LOG_LEVEL_ERROR,
+ "Out of memory while decoding URL: %s", subject);
+ freez(subject);
+ return NULL;
+ }
+
+ segments = ssplit(subject, "?&", url_segments, max_segments);
+
+ while (segments-- > 0)
+ {
+ char *dtoken = url_decode(url_segments[segments]);
+ if (NULL == dtoken)
+ {
+ log_error(LOG_LEVEL_ERROR, "Unable to decode \"%s\".", url_segments[segments]);
+ continue;
+ }
+ url_segment = strstr(dtoken, "http://");
+ if (NULL == url_segment)
+ {
+ url_segment = strstr(dtoken, "https://");
+ }
+ if (NULL != url_segment)
+ {
+ url_segment = strdup_or_die(url_segment);
+ freez(dtoken);
+ break;
+ }
+ freez(dtoken);
+ }
+ freez(subject);
+ freez(url_segments);
+
+ if (url_segment == NULL)
+ {
+ return NULL;
+ }
+ subject = url_segment;
+ }
+ else
+ {
+ /* Look for a URL inside this one, without decoding anything. */
+ log_error(LOG_LEVEL_REDIRECTS,
+ "Checking \"%s\" for unencoded 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 (the now obsolete) RFC 2616 section 14.30
+ * the URL has to be absolute and if the user tries:
+ * +redirect{sadly/this/will/be/parsed/as/pcrs_command.html}
+ * she would get undefined results anyway.
+ *
+ * RFC 7231 7.1.2 actually allows relative references,
+ * but those start with a leading slash (RFC 3986 4.2) and
+ * thus can't be mistaken for pcrs commands either.
+ */
+
+ 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 (url_requires_percent_encoding(new_url))
+ {
+ char *encoded_url;
+ log_error(LOG_LEVEL_REDIRECTS, "Percent-encoding redirect URL: %N",
+ strlen(new_url), new_url);
+ encoded_url = percent_encode_url(new_url);
+ freez(new_url);
+ if (encoded_url == NULL)
+ {
+ return cgi_error_memory();
+ }
+ new_url = encoded_url;
+ assert(FALSE == url_requires_percent_encoding(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();
+ }
+
+ rsp->status = strdup_or_die("302 Local Redirect from Privoxy");
+ if (enlist_unique_header(rsp->headers, "Location", new_url))
+ {
+ freez(new_url);
+ free_http_response(rsp);
+ return cgi_error_memory();
+ }
+ rsp->crunch_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 should be treated
+ * as image URL or not.
+ *
+ * Parameters :
+ * 1 : csp = Current client state (buffers, headers, etc...)
+ *
+ * Returns : True (nonzero) if URL is an image URL, false (0)
+ * otherwise
+ *
+ *********************************************************************/
+int is_imageurl(const struct client_state *csp)
+{
+ 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 pattern_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;
+ }