Date: Fri, 19 Jan 2001 11:36:31 +0800 (CST) From: Christopher Hall <hsw@acm.org> To: FreeBSD-gnats-submit@freebsd.org Subject: gnu/24445: ipnat does not parse its file properly Message-ID: <200101190336.f0J3aVe43887@w40.tucheng.generalresources.com>
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>Number: 24445
>Category: gnu
>Synopsis: ipnat does not parse its file properly
>Confidential: no
>Severity: serious
>Priority: high
>Responsible: freebsd-bugs
>State: open
>Quarter:
>Keywords:
>Date-Required:
>Class: sw-bug
>Submitter-Id: current-users
>Arrival-Date: Thu Jan 18 19:40:01 PST 2001
>Closed-Date:
>Last-Modified:
>Originator: Christopher Hall
>Release: FreeBSD 4.2-STABLE i386
>Organization:
>Environment:
4.2-STABLE FreeBSD 4.2-STABLE #0: Thu Jan 18 13:15:08 CST 2001
>Description:
Using the following configuration file:
map fxp1 192.168.1.250/16 -> 1.2.3.4/32 portmap tcp/udp 40000:60000
map fxp1 192.168.1.250/16 -> 1.2.3.4/32
##rdr fxp0 192.168.1.250/32 port 80 -> 4.5.6.7 port 80
rdr fxp0 192.168.1.250/32 port http -> 4.5.6.7 port http
rdr fxp0 192.168.1.250/32 port https -> 4.5.6.7 port https
Get errors like this
4: unknown service "http".
4: syntax error in "rdr"
5: unknown service "https".
5: syntax error in "rdr"
can stop error by:
a) remove the '##' in line 3
b) comment out line 1
c) move line 1 to end of file
The problem is caused by a global variable in the file common.c
its definition is: char *proto = NULL;
the file natparse.c uses the routine "portnum" to convert the
string "http" to a number
'proto' is now pointing at the position in the line buffer where
the string "tcp/udp" used to be from line 1 of config file.
Therefore the variable 'proto' points at the ".7" of the ip number when
parsing line 4.
Using numeric port number does not access the global 'proto' variable in
portnum and later in natparse sets 'proto' pointing to static string "tcp"
for parsing the remaining lines.
Any line that contains a protocol will set the 'proto' variable for
the next line. If this line is longer the 'proto' variable will be
pointing at an invalid string.
>How-To-Repeat:
ipnat -f ipnat.conf (see above for for config file contents)
>Fix:
Don't use global variables like this!
Should eliminate the global proto variable and pass the protocol
as a parameter to portnum. It looks like proto variable
is only shared by natparse.c parse.c and common.c.
As far as I can tell only the 'rdr' command is affected, because
the protocol specified on the end of the line so the 'proto' variable
gets set too late.
In natparse.c the is a section to decode the protocol, this would
have to be move before the first portnum call. However the method
of parsing the command line by using "cpp++;" to bump the toke pointer.
The easiest would be to change the syntax of the "rdr" command
from:
rdr le0 203.1.2.3/32 port 80 -> 203.1.2.3,203.1.2.4 port 80 tcp
to:
rdr tcp le0 203.1.2.3/32 port 80 -> 203.1.2.3,203.1.2.4 port 80
Temporary Fix:
Assume the protocol will be tcp or udp and that the same number
applies to both.
To do this, just add the following line to the start of the
function natparse in natparse.c:
proto = NULL;
Any better ideas?
>Release-Note:
>Audit-Trail:
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