Bugtraq mailing list archives
tcpd remarks warning
From: thor () IRCITY ORG (Stefano Torricella)
Date: Fri, 2 Apr 1999 09:32:59 +0200
Hi, Some days ago i've had a problem with tcpd 1.10 - patchlevel 7.6. I suppose that the problem is in the parser routine but i haven't checked the source. I try to describe the bug : suppose you have an hosts.access or hosts.deny file like this # hosts.deny # some remarks in.telnetd: 123.234.12.34, 98.76.54.32, \ 32.198.76.54 ... now i want to remove 98.76.54.32 on the first line but i want the line for remember or for restoring them later, so i duplicate the line and remarks the original # hosts.deny # some remarks #in.telnetd: 123.234.12.34, 98.76.54.32, \ in.telnetd: 123.234.12.34, \ 32.198.76.54 ... well in this manner i've removed all the address !!! because the \ on the end of the remark line is treated how a continue of the normal line and in effect the comment continue for the next line and all the above line until the first line with the first char <> from space or tab !! i think that when a remark line is found, the parser must go to the next line without checking what is in the comment line. if you write a simple shell program : #!/bin/sh # this is a comment \ echo "work !!" the bash or the bourne shell ignore \ on the comment line ! Thinking that this is a general behavior for all the unix program i've contacted the author and manteiner of tcpd but for him this is correct. In all the case this may be dangerous so other sysadm may be interested on this behaviour "bug" found in linux (debian 2.1 distribution but i think may other distribution are vulnerable) OpenBSD 2.4 isn't vulnerable. hope that this may help you ... and sorry for my rusted english ;-) --- ;---+--- bye| bye|hor
Current thread:
- tcpd remarks warning Stefano Torricella (Apr 01)
- Re: tcpd remarks warning Greg A. Woods (Apr 02)
- Re: tcpd remarks warning John Line (Apr 02)
- Re: tcpd remarks warning Doug White (Apr 02)
- Re: tcpd remarks warning Paul M. Cardon (Apr 02)
- Re: tcpd remarks warning Wietse Venema (Apr 02)
- Re: tcpd remarks warning Wietse Venema (Apr 02)
- Re: tcpd remarks warning Greg A. Woods (Apr 02)