From b60b23600ca14efd4017a9f23b6e2044118a886c Mon Sep 17 00:00:00 2001
From: Ingo Schwarze <schwarze@openbsd.org>
Date: Tue, 22 Jul 2014 18:14:13 +0000
Subject: Security fix to prevent XSS attacks: Restrict the character set of
 strings passed into html_alloc(), in particular architecture names that come
 from the QUERY_STRING, but also SCRIPT_NAME and manpath.conf content for
 additional safety, and bail out safely on violations. Issue reported by
 Sebastien Marie <semarie-openbsd at latrappe dot fr>.

---
 man.cgi.8 | 42 ++++++++++++++++++++++++++++++++++++++++--
 1 file changed, 40 insertions(+), 2 deletions(-)

(limited to 'man.cgi.8')

diff --git a/man.cgi.8 b/man.cgi.8
index 74ab525a..69335e63 100644
--- a/man.cgi.8
+++ b/man.cgi.8
@@ -1,4 +1,4 @@
-.\"     $Id: man.cgi.8,v 1.8 2014/07/21 15:45:17 schwarze Exp $
+.\"     $Id: man.cgi.8,v 1.9 2014/07/22 18:14:13 schwarze Exp $
 .\"
 .\" Copyright (c) 2014 Ingo Schwarze <schwarze@openbsd.org>
 .\"
@@ -14,7 +14,7 @@
 .\" ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
 .\" OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
 .\"
-.Dd $Mdocdate: July 21 2014 $
+.Dd $Mdocdate: July 22 2014 $
 .Dt MAN.CGI 8
 .Os
 .Sh NAME
@@ -267,6 +267,34 @@ For backward compatibility with the traditional
 is supported as an alias for
 .Cm sec .
 .El
+.Ss Restricted character set
+For security reasons, in particular to prevent cross site scripting
+attacks, some strings used by
+.Nm
+can only contain the following characters:
+.Pp
+.Bl -dash -compact -offset indent
+.It
+lower case and upper case ASCII letters
+.It
+the ten decimal digits
+.It
+the dash
+.Pq Sq -
+.It
+the dot
+.Pq Sq \&.
+.It
+the slash
+.Pq Sq /
+.It
+the underscore
+.Pq Sq _
+.El
+.Pp
+In particular, this applies to the
+.Ev SCRIPT_NAME ,
+to all manpaths, and to all architecture names.
 .Sh ENVIRONMENT
 The web server may pass the following CGI variables to
 .Nm :
@@ -293,6 +321,10 @@ binary relative to the server root, usually
 .Pa /cgi-bin/man.cgi .
 This is used for generating URIs to be embedded
 in generated HTML code and HTTP headers.
+If this contains any character not contained in the
+.Sx Restricted character set ,
+.Nm
+reports an internal server error and exits without doing anything.
 .El
 .Sh FILES
 .Bl -tag -width Ds
@@ -332,6 +364,12 @@ Manual pages documenting
 itself, linked from the index page.
 .It Pa /man/manpath.conf
 The list of available manpaths, one per line.
+If any of the lines in this file contains a slash
+.Pq Sq /
+or any character not contained in the
+.Sx Restricted character set ,
+.Nm
+reports an internal server error and exits without doing anything.
 .It Pa /man/OpenBSD-current/man1/mandoc.1
 An example
 .Xr mdoc 7
-- 
cgit v1.2.3-56-ge451