Bugtraq mailing list archives
Re: /proc filesystem allows bypassing directory permissions on Linux
From: Anton Ivanov <anton.ivanov () kot-begemot co uk>
Date: Sat, 24 Oct 2009 20:27:25 +0100
Not that I would have expected anything different considering who posted it in the first place.Thus Debian kernel team should be blamed for that misbehaviour. Don't worry, hardlinks behave just the same way, as you describe. Use authentic Linux kernels, if you dislike that.
Just tested it on my colo where the provider is using some homebrew derived from the upstream Linux kernel. In any case Pavel was most likely using Suse and I asked someone to give it a go on one of all Ubuntu varieties. So even if it is not present upstream it is in a patch which more than one distro has adopted (f.e. ptrace fixes). I have filed this as a security bug on debian by the way. So you can express your opinions about the supposed "inferiority" of their patches directly to them. Note - in order to get the descriptor in the first place you need to have access to the directory and the user to change it down to 700 later. So this is actually of use predominantly under race conditions and such. Limited use, but some use none the less. I can think of at least a couple of places where I can wreak some havoc with that. -- Understanding is a three-edged sword: your side, their side, and the truth. --Kosh Naranek A. R. Ivanov E-mail: anton.ivanov () kot-begemot co uk WWW: http://www.kot-begemot.co.uk/
Current thread:
- Re: /proc filesystem allows bypassing directory permissions on Linux, (continued)
- Re: /proc filesystem allows bypassing directory permissions on Linux Marco Verschuur (Oct 28)
- Re: /proc filesystem allows bypassing directory permissions on Linux Pavel Machek (Oct 29)
- Re: /proc filesystem allows bypassing directory permissions on Martin Rex (Oct 29)
- Re: /proc filesystem allows bypassing directory permissions on Pavel Machek (Oct 30)
- Re: /proc filesystem allows bypassing directory permissions on Linux Anton Ivanov (Oct 26)
- Re: /proc filesystem allows bypassing directory permissions on Linux Dan Yefimov (Oct 26)
- Re: /proc filesystem allows bypassing directory permissions on Linux Anton Ivanov (Oct 26)
- Re: /proc filesystem allows bypassing directory permissions on Linux Dan Yefimov (Oct 26)
- Re: /proc filesystem allows bypassing directory permissions on Linux Anton Ivanov (Oct 26)
- Re: /proc filesystem allows bypassing directory permissions on Linux Dan Yefimov (Oct 26)
- Re: /proc filesystem allows bypassing directory permissions on Linux Anton Ivanov (Oct 26)
- Re: /proc filesystem allows bypassing directory permissions on Linux Pavel Machek (Oct 29)
- Re: /proc filesystem allows bypassing directory permissions on Linux Ivan Jager (Oct 28)
- Re: /proc filesystem allows bypassing directory permissions on Linux Klaus Lichtenwalder (Oct 26)
- Re: /proc filesystem allows bypassing directory permissions on Linux Pavel Kankovsky (Oct 26)
- Re: /proc filesystem allows bypassing directory permissions on Linux Matthew Dempsky (Oct 26)
- Re: /proc filesystem allows bypassing directory permissions on Linux Tony Finch (Oct 27)
- Re: /proc filesystem allows bypassing directory permissions on Linux Matthew Dempsky (Oct 28)