+/*********************************************************************
+ *
+ * Function : client_if_modified_since
+ *
+ * Description : Remove or modify the If-Modified-Since header.
+ *
+ * Parameters :
+ * 1 : csp = Current client state (buffers, headers, etc...)
+ * 2 : header = On input, pointer to header to modify.
+ * On output, pointer to the modified header, or NULL
+ * to remove the header. This function frees the
+ * original string if necessary.
+ *
+ * Returns : JB_ERR_OK on success, or
+ * JB_ERR_MEMORY on out-of-memory error.
+ *
+ *********************************************************************/
+static jb_err client_if_modified_since(struct client_state *csp, char **header)
+{
+ char newheader[50];
+#ifdef HAVE_GMTIME_R
+ struct tm gmt;
+#endif
+ struct tm *timeptr = NULL;
+ time_t tm = 0;
+ const char *newval;
+ long int rtime;
+ long int hours, minutes, seconds;
+ int negative = 0;
+ char * endptr;
+
+ if ( 0 == strcmpic(*header, "If-Modified-Since: Wed, 08 Jun 1955 12:00:00 GMT"))
+ {
+ /*
+ * The client got an error message because of a temporary problem,
+ * the problem is gone and the client now tries to revalidate our
+ * error message on the real server. The revalidation would always
+ * end with the transmission of the whole document and there is
+ * no need to expose the bogus If-Modified-Since header.
+ */
+ log_error(LOG_LEVEL_HEADER, "Crunching useless If-Modified-Since header.");
+ freez(*header);
+ }
+ else if (csp->action->flags & ACTION_HIDE_IF_MODIFIED_SINCE)
+ {
+ newval = csp->action->string[ACTION_STRING_IF_MODIFIED_SINCE];
+
+ if ((0 == strcmpic(newval, "block")))
+ {
+ log_error(LOG_LEVEL_HEADER, "Crunching %s", *header);
+ freez(*header);
+ }
+ else /* add random value */
+ {
+ const char *header_time = *header + sizeof("If-Modified-Since:");
+
+ if (JB_ERR_OK != parse_header_time(header_time, &tm))
+ {
+ log_error(LOG_LEVEL_HEADER, "Couldn't parse: %s in %s (crunching!)", header_time, *header);
+ freez(*header);
+ }
+ else
+ {
+ rtime = strtol(newval, &endptr, 0);
+ if (rtime)
+ {
+ log_error(LOG_LEVEL_HEADER, "Randomizing: %s (random range: %d minut%s)",
+ *header, rtime, (rtime == 1 || rtime == -1) ? "e": "es");
+ if (rtime < 0)
+ {
+ rtime *= -1;
+ negative = 1;
+ }
+ rtime *= 60;
+ rtime = pick_from_range(rtime);
+ }
+ else
+ {
+ log_error(LOG_LEVEL_ERROR, "Random range is 0. Assuming time transformation test.",
+ *header);
+ }
+ tm += rtime * (negative ? -1 : 1);
+#ifdef HAVE_GMTIME_R
+ timeptr = gmtime_r(&tm, &gmt);
+#elif FEATURE_PTHREAD
+ pthread_mutex_lock(&gmtime_mutex);
+ timeptr = gmtime(&tm);
+ pthread_mutex_unlock(&gmtime_mutex);
+#else
+ timeptr = gmtime(&tm);
+#endif
+ strftime(newheader, sizeof(newheader), "%a, %d %b %Y %H:%M:%S GMT", timeptr);
+
+ freez(*header);
+ *header = strdup("If-Modified-Since: ");
+ string_append(header, newheader);
+
+ if (*header == NULL)
+ {
+ log_error(LOG_LEVEL_HEADER, "Insufficent memory, header crunched without replacement.");
+ return JB_ERR_MEMORY;
+ }
+
+ if (LOG_LEVEL_HEADER & debug) /* Save cycles if the user isn't interested. */
+ {
+ hours = rtime / 3600;
+ minutes = rtime / 60 % 60;
+ seconds = rtime % 60;
+
+ log_error(LOG_LEVEL_HEADER, "Randomized: %s (%s %d hou%s %d minut%s %d second%s",
+ *header, (negative) ? "subtracted" : "added", hours, (hours == 1) ? "r" : "rs",
+ minutes, (minutes == 1) ? "e" : "es", seconds, (seconds == 1) ? ")" : "s)");
+ }
+ }
+ }
+ }
+
+ return JB_ERR_OK;
+}
+
+
+/*********************************************************************
+ *
+ * Function : client_if_none_match
+ *
+ * Description : Remove the If-None-Match header.
+ *
+ * Parameters :
+ * 1 : csp = Current client state (buffers, headers, etc...)
+ * 2 : header = On input, pointer to header to modify.
+ * On output, pointer to the modified header, or NULL
+ * to remove the header. This function frees the
+ * original string if necessary.
+ *
+ * Returns : JB_ERR_OK on success, or
+ * JB_ERR_MEMORY on out-of-memory error.
+ *
+ *********************************************************************/
+static jb_err client_if_none_match(struct client_state *csp, char **header)
+{
+ if (csp->action->flags & ACTION_CRUNCH_IF_NONE_MATCH)
+ {
+ log_error(LOG_LEVEL_HEADER, "Crunching %s", *header);
+ freez(*header);
+ }
+
+ return JB_ERR_OK;
+}
+
+
+/*********************************************************************
+ *
+ * Function : client_x_filter
+ *
+ * Description : Disables filtering if the client set "X-Filter: No".
+ * Called from `sed'.
+ *
+ * Parameters :
+ * 1 : csp = Current client state (buffers, headers, etc...)
+ * 2 : header = On input, pointer to header to modify.
+ * On output, pointer to the modified header, or NULL
+ * to remove the header. This function frees the
+ * original string if necessary.
+ *
+ * Returns : JB_ERR_OK on success
+ *
+ *********************************************************************/
+jb_err client_x_filter(struct client_state *csp, char **header)
+{
+ if ( 0 == strcmpic(*header, "X-Filter: No"))
+ {
+ if (!(csp->config->feature_flags & RUNTIME_FEATURE_HTTP_TOGGLE))
+ {
+ log_error(LOG_LEVEL_INFO, "Ignored the client's request to fetch without filtering.");
+ }
+ else
+ {
+ if (csp->action->flags & ACTION_FORCE_TEXT_MODE)
+ {
+ log_error(LOG_LEVEL_HEADER,
+ "force-text-mode overruled the client's request to fetch without filtering!");
+ }
+ else
+ {
+ csp->content_type = CT_TABOO; /* XXX: This hack shouldn't be necessary */
+ csp->flags |= CSP_FLAG_NO_FILTERING;
+ log_error(LOG_LEVEL_HEADER, "Accepted the client's request to fetch without filtering.");
+ }
+ log_error(LOG_LEVEL_HEADER, "Crunching %s", *header);
+ freez(*header);
+ }
+ }
+ return JB_ERR_OK;
+}
+
+
+/*********************************************************************
+ *
+ * Function : client_range
+ *
+ * Description : Removes Range, Request-Range and If-Range headers if
+ * content filtering is enabled. If the client's version
+ * of the document has been altered by Privoxy, the server
+ * could interpret the range differently than the client
+ * intended in which case the user could end up with
+ * corrupted content.
+ *
+ * Parameters :
+ * 1 : csp = Current client state (buffers, headers, etc...)
+ * 2 : header = On input, pointer to header to modify.
+ * On output, pointer to the modified header, or NULL
+ * to remove the header. This function frees the
+ * original string if necessary.
+ *
+ * Returns : JB_ERR_OK
+ *
+ *********************************************************************/
+static jb_err client_range(struct client_state *csp, char **header)
+{
+ if (content_filters_enabled(csp))
+ {
+ log_error(LOG_LEVEL_HEADER, "Content filtering is enabled."
+ " Crunching: \'%s\' to prevent range-mismatch problems.", *header);
+ freez(*header);
+ }
+
+ return JB_ERR_OK;
+}
+
+/* the following functions add headers directly to the header list */
+
+/*********************************************************************
+ *
+ * Function : client_host_adder
+ *
+ * Description : Adds the Host: header field if it is missing.
+ * Called from `sed'.
+ *
+ * Parameters :
+ * 1 : csp = Current client state (buffers, headers, etc...)
+ *
+ * Returns : JB_ERR_OK on success, or
+ * JB_ERR_MEMORY on out-of-memory error.
+ *
+ *********************************************************************/
+static jb_err client_host_adder(struct client_state *csp)
+{
+ char *p;
+ jb_err err;
+
+ if (csp->flags & CSP_FLAG_HOST_HEADER_IS_SET)
+ {
+ /* Header already set by the client, nothing to do. */
+ return JB_ERR_OK;
+ }
+
+ if ( !csp->http->hostport || !*(csp->http->hostport))
+ {
+ /* XXX: When does this happen and why is it OK? */
+ log_error(LOG_LEVEL_INFO, "Weirdness in client_host_adder detected and ignored.");
+ return JB_ERR_OK;
+ }
+
+ /*
+ * remove 'user:pass@' from 'proto://user:pass@host'
+ */
+ if ( (p = strchr( csp->http->hostport, '@')) != NULL )
+ {
+ p++;
+ }
+ else
+ {
+ p = csp->http->hostport;
+ }
+
+ /* XXX: Just add it, we already made sure that it will be unique */
+ log_error(LOG_LEVEL_HEADER, "addh-unique: Host: %s", p);
+ err = enlist_unique_header(csp->headers, "Host", p);
+ return err;
+
+}
+
+
+#if 0
+/*********************************************************************
+ *
+ * Function : client_accept_encoding_adder
+ *
+ * Description : Add an Accept-Encoding header to the client's request
+ * that disables compression if the action applies, and
+ * the header is not already there. Called from `sed'.
+ * Note: For HTTP/1.0, the absence of the header is enough.
+ *
+ * Parameters :
+ * 1 : csp = Current client state (buffers, headers, etc...)
+ *
+ * Returns : JB_ERR_OK on success, or
+ * JB_ERR_MEMORY on out-of-memory error.
+ *
+ *********************************************************************/
+static jb_err client_accept_encoding_adder(struct client_state *csp)
+{
+ if ( ((csp->action->flags & ACTION_NO_COMPRESSION) != 0)
+ && (!strcmpic(csp->http->ver, "HTTP/1.1")) )
+ {
+ return enlist_unique(csp->headers, "Accept-Encoding: identity;q=1.0, *;q=0", 16);
+ }
+
+ return JB_ERR_OK;
+}
+#endif
+
+
+/*********************************************************************
+ *
+ * Function : client_xtra_adder
+ *
+ * Description : Used in the add_client_headers list. Called from `sed'.
+ *
+ * Parameters :
+ * 1 : csp = Current client state (buffers, headers, etc...)
+ *
+ * Returns : JB_ERR_OK on success, or
+ * JB_ERR_MEMORY on out-of-memory error.
+ *
+ *********************************************************************/
+static jb_err client_xtra_adder(struct client_state *csp)
+{
+ struct list_entry *lst;
+ jb_err err;
+
+ for (lst = csp->action->multi[ACTION_MULTI_ADD_HEADER]->first;
+ lst ; lst = lst->next)
+ {
+ log_error(LOG_LEVEL_HEADER, "addh: %s", lst->str);
+ err = enlist(csp->headers, lst->str);
+ if (err)
+ {
+ return err;
+ }
+
+ }
+
+ return JB_ERR_OK;
+}
+
+
+/*********************************************************************
+ *
+ * Function : connection_close_adder
+ *
+ * Description : "Temporary" fix for the needed but missing HTTP/1.1
+ * support. Adds a "Connection: close" header to csp->headers
+ * unless the header was already present. Called from `sed'.
+ *
+ * FIXME: This whole function shouldn't be neccessary!
+ *
+ * Parameters :
+ * 1 : csp = Current client state (buffers, headers, etc...)
+ *
+ * Returns : JB_ERR_OK on success, or
+ * JB_ERR_MEMORY on out-of-memory error.
+ *
+ *********************************************************************/
+static jb_err connection_close_adder(struct client_state *csp)
+{
+ const unsigned int flags = csp->flags;
+
+ /*
+ * Return right away if
+ *
+ * - we're parsing server headers and the server header
+ * "Connection: close" is already set, or if
+ *
+ * - we're parsing client headers and the client header
+ * "Connection: close" is already set.
+ */
+ if ((flags & CSP_FLAG_CLIENT_HEADER_PARSING_DONE
+ && flags & CSP_FLAG_SERVER_CONNECTION_CLOSE_SET)
+ ||(!(flags & CSP_FLAG_CLIENT_HEADER_PARSING_DONE)
+ && flags & CSP_FLAG_CLIENT_CONNECTION_CLOSE_SET))
+ {
+ return JB_ERR_OK;
+ }
+
+ log_error(LOG_LEVEL_HEADER, "Adding: Connection: close");
+
+ return enlist(csp->headers, "Connection: close");
+}
+
+
+/*********************************************************************
+ *
+ * Function : server_http
+ *
+ * Description : - Save the HTTP Status into csp->http->status
+ * - Set CT_TABOO to prevent filtering if the answer
+ * is a partial range (HTTP status 206)
+ * - Rewrite HTTP/1.1 answers to HTTP/1.0 if +downgrade
+ * action applies.
+ *
+ * Parameters :
+ * 1 : csp = Current client state (buffers, headers, etc...)
+ * 2 : header = On input, pointer to header to modify.
+ * On output, pointer to the modified header, or NULL
+ * to remove the header. This function frees the
+ * original string if necessary.
+ *
+ * Returns : JB_ERR_OK on success, or
+ * JB_ERR_MEMORY on out-of-memory error.
+ *
+ *********************************************************************/
+static jb_err server_http(struct client_state *csp, char **header)
+{
+ sscanf(*header, "HTTP/%*d.%*d %d", &(csp->http->status));
+ if (csp->http->status == 206)
+ {
+ csp->content_type = CT_TABOO;
+ }
+
+ if ((csp->action->flags & ACTION_DOWNGRADE) != 0)
+ {
+ /* XXX: Should we do a real validity check here? */
+ if (strlen(*header) > 8)
+ {
+ (*header)[7] = '0';
+ log_error(LOG_LEVEL_HEADER, "Downgraded answer to HTTP/1.0");
+ }
+ else
+ {
+ /*
+ * XXX: Should we block the request or
+ * enlist a valid status code line here?
+ */
+ log_error(LOG_LEVEL_INFO, "Malformed server response detected. "
+ "Downgrading to HTTP/1.0 impossible.");
+ }
+ }
+
+ return JB_ERR_OK;
+}
+
+
+/*********************************************************************
+ *
+ * Function : server_set_cookie
+ *
+ * Description : Handle the server "cookie" header properly.
+ * Log cookie to the jar file. Then "crunch",
+ * accept or rewrite it to a session cookie.
+ * Called from `sed'.
+ *
+ * TODO: Allow the user to specify a new expiration
+ * time to cause the cookie to expire even before the
+ * browser is closed.
+ *
+ * Parameters :
+ * 1 : csp = Current client state (buffers, headers, etc...)
+ * 2 : header = On input, pointer to header to modify.
+ * On output, pointer to the modified header, or NULL
+ * to remove the header. This function frees the
+ * original string if necessary.
+ *
+ * Returns : JB_ERR_OK on success, or
+ * JB_ERR_MEMORY on out-of-memory error.
+ *
+ *********************************************************************/
+static jb_err server_set_cookie(struct client_state *csp, char **header)
+{
+ time_t now;
+ time_t cookie_time;
+ struct tm tm_now;
+ time(&now);
+
+#ifdef FEATURE_COOKIE_JAR
+ if (csp->config->jar)
+ {
+ /*
+ * Write timestamp into outbuf.
+ *
+ * Complex because not all OSs have tm_gmtoff or
+ * the %z field in strftime()
+ */
+ char tempbuf[ BUFFER_SIZE ];
+
+#ifdef HAVE_LOCALTIME_R
+ tm_now = *localtime_r(&now, &tm_now);
+#elif FEATURE_PTHREAD
+ pthread_mutex_lock(&localtime_mutex);
+ tm_now = *localtime (&now);
+ pthread_mutex_unlock(&localtime_mutex);
+#else
+ tm_now = *localtime (&now);
+#endif
+ strftime(tempbuf, BUFFER_SIZE-6, "%b %d %H:%M:%S ", &tm_now);
+
+ /* strlen("set-cookie: ") = 12 */
+ fprintf(csp->config->jar, "%s %s\t%s\n", tempbuf, csp->http->host, *header + 12);
+ }
+#endif /* def FEATURE_COOKIE_JAR */
+
+ if ((csp->action->flags & ACTION_NO_COOKIE_SET) != 0)
+ {
+ log_error(LOG_LEVEL_HEADER, "Crunching incoming cookie: %s", *header);
+ freez(*header);
+ }
+ else if ((csp->action->flags & ACTION_NO_COOKIE_KEEP) != 0)
+ {
+ /* Flag whether or not to log a message */
+ int changed = 0;
+
+ /* A variable to store the tag we're working on */
+ char *cur_tag;
+
+ /* Skip "Set-Cookie:" (11 characters) in header */
+ cur_tag = *header + 11;
+
+ /* skip whitespace between "Set-Cookie:" and value */
+ while (*cur_tag && ijb_isspace(*cur_tag))
+ {
+ cur_tag++;
+ }
+
+ /* Loop through each tag in the cookie */
+ while (*cur_tag)
+ {
+ /* Find next tag */
+ char *next_tag = strchr(cur_tag, ';');
+ if (next_tag != NULL)
+ {
+ /* Skip the ';' character itself */
+ next_tag++;
+
+ /* skip whitespace ";" and start of tag */
+ while (*next_tag && ijb_isspace(*next_tag))
+ {
+ next_tag++;
+ }
+ }
+ else
+ {
+ /* "Next tag" is the end of the string */
+ next_tag = cur_tag + strlen(cur_tag);
+ }
+
+ /*
+ * Check the expiration date to see
+ * if the cookie is still valid, if yes,
+ * rewrite it to a session cookie.
+ */
+ if ((strncmpic(cur_tag, "expires=", 8) == 0) && *(cur_tag + 8))
+ {
+ char *expiration_date = cur_tag + 8; /* Skip "[Ee]xpires=" */
+
+ /* Did we detect the date properly? */
+ if (JB_ERR_OK != parse_header_time(expiration_date, &cookie_time))
+ {
+ /*
+ * Nope, treat it as if it was still valid.
+ *
+ * XXX: Should we remove the whole cookie instead?
+ */
+ log_error(LOG_LEVEL_ERROR,
+ "Can't parse \'%s\', send by %s. Unsupported time format?", cur_tag, csp->http->url);
+ memmove(cur_tag, next_tag, strlen(next_tag) + 1);
+ changed = 1;
+ }
+ else
+ {
+ /*
+ * Yes. Check if the cookie is still valid.
+ *
+ * If the cookie is already expired it's probably
+ * a delete cookie and even if it isn't, the browser
+ * will discard it anyway.
+ */
+
+ /*
+ * XXX: timegm() isn't available on some AmigaOS
+ * versions and our replacement doesn't work.
+ *
+ * Our options are to either:
+ *
+ * - disable session-cookies-only completely if timegm
+ * is missing,
+ *
+ * - to simply remove all expired tags, like it has
+ * been done until Privoxy 3.0.6 and to live with
+ * the consequence that it can cause login/logout
+ * problems on servers that don't validate their
+ * input properly, or
+ *
+ * - to replace it with mktime in which
+ * case there is a slight chance of valid cookies
+ * passing as already expired.
+ *
+ * This is the way it's currently done and it's not
+ * as bad as it sounds. If the missing GMT offset is
+ * enough to change the result of the expiration check
+ * the cookie will be only valid for a few hours
+ * anyway, which in many cases will be shorter
+ * than a browser session.
+ */
+ if (cookie_time - now < 0)
+ {
+ log_error(LOG_LEVEL_HEADER,
+ "Cookie \'%s\' is already expired and can pass unmodified.", *header);
+ /* Just in case some clown sets more then one expiration date */
+ cur_tag = next_tag;
+ }
+ else
+ {
+ /*
+ * Still valid, delete expiration date by copying
+ * the rest of the string over it.
+ *
+ * (Note that we cannot just use "strcpy(cur_tag, next_tag)",
+ * since the behaviour of strcpy is undefined for overlapping
+ * strings.)
+ */
+ memmove(cur_tag, next_tag, strlen(next_tag) + 1);
+
+ /* That changed the header, need to issue a log message */
+ changed = 1;
+
+ /*
+ * Note that the next tag has now been moved to *cur_tag,
+ * so we do not need to update the cur_tag pointer.
+ */
+ }
+ }
+
+ }
+ else
+ {
+ /* Move on to next cookie tag */
+ cur_tag = next_tag;
+ }
+ }
+
+ if (changed)
+ {
+ assert(NULL != *header);
+ log_error(LOG_LEVEL_HEADER, "Cookie rewritten to a temporary one: %s",
+ *header);
+ }
+ }
+
+ return JB_ERR_OK;
+}
+
+
+#ifdef FEATURE_FORCE_LOAD