===================================================================
RCS file: /cvs/mandoc/cgi.c,v
retrieving revision 1.74
retrieving revision 1.76
diff -u -p -r1.74 -r1.76
--- mandoc/cgi.c	2014/07/18 14:46:25	1.74
+++ mandoc/cgi.c	2014/07/19 11:35:12	1.76
@@ -1,4 +1,4 @@
-/*	$Id: cgi.c,v 1.74 2014/07/18 14:46:25 schwarze Exp $ */
+/*	$Id: cgi.c,v 1.76 2014/07/19 11:35:12 schwarze Exp $ */
 /*
  * Copyright (c) 2011, 2012 Kristaps Dzonsons <kristaps@bsd.lv>
  * Copyright (c) 2014 Ingo Schwarze <schwarze@usta.de>
@@ -79,7 +79,6 @@ static	void		 resp_searchform(const struct req *);
 static	void		 resp_show(const struct req *, const char *);
 
 static	const char	 *scriptname; /* CGI script name */
-static	const char	 *httphost; /* hostname used in the URIs */
 
 static	const int sec_prios[] = {1, 4, 5, 8, 6, 3, 7, 2, 9};
 static	const char *const sec_numbers[] = {
@@ -467,6 +466,17 @@ resp_searchform(const struct req *req)
 	puts("<!-- End search form. //-->");
 }
 
+static int
+validate_filename(const char *file)
+{
+
+	if ('.' == file[0] && '/' == file[1])
+		file += 2;
+
+	return ( ! (strstr(file, "../") || strstr(file, "/..") ||
+	    (strncmp(file, "man", 3) && strncmp(file, "cat", 3))));
+}
+
 static void
 pg_index(const struct req *req)
 {
@@ -524,14 +534,23 @@ pg_searchres(const struct req *req, struct manpage *r,
 	int		 prio, priouse;
 	char		 sec;
 
+	for (i = 0; i < sz; i++) {
+		if (validate_filename(r[i].file))
+			continue;
+		fprintf(stderr, "invalid filename %s in %s database\n",
+		    r[i].file, req->q.manpath);
+		pg_error_internal();
+		return;
+	}
+
 	if (1 == sz) {
 		/*
 		 * If we have just one result, then jump there now
 		 * without any delay.
 		 */
 		printf("Status: 303 See Other\r\n");
-		printf("Location: http://%s%s/%s/%s?",
-		    httphost, scriptname, req->q.manpath, r[0].file);
+		printf("Location: %s/%s/%s?",
+		    scriptname, req->q.manpath, r[0].file);
 		http_printquery(req);
 		printf("\r\n"
 		     "Content-Type: text/html; charset=utf-8\r\n"
@@ -778,7 +797,8 @@ format(const struct req *req, const char *file)
 static void
 resp_show(const struct req *req, const char *file)
 {
-	if ('.' == file[0] || '/' == file[1])
+
+	if ('.' == file[0] && '/' == file[1])
 		file += 2;
 
 	if ('c' == *file)
@@ -811,6 +831,12 @@ pg_show(const struct req *req, const char *path)
 		return;
 	}
 
+	if ( ! validate_filename(sub)) {
+		pg_error_badrequest(
+		    "You specified an invalid manual file.");
+		return;
+	}
+
 	resp_begin_html(200, NULL);
 	resp_searchform(req);
 	resp_show(req, sub);
@@ -906,9 +932,6 @@ main(void)
 
 	if (NULL == (scriptname = getenv("SCRIPT_NAME")))
 		scriptname = "";
-
-	if (NULL == (httphost = getenv("HTTP_HOST")))
-		httphost = "localhost";
 
 	/*
 	 * First we change directory into the MAN_DIR so that