Bugtraq mailing list archives
Re: /proc filesystem allows bypassing directory permissions on Linux
From: Pavel Machek <pavel () ucw cz>
Date: Mon, 26 Oct 2009 16:58:35 +0100
guest certianly does not have permission to ptrace() pavel's processes, so...But guest has permissions to ptrace() his own processes. If we remember your original report, he abuses input redirection of bash run by himself. So again, there's no real security hole here.guest abuses ptrace permissions on his own processes to write to pavel's files... no, that obviously is not security hole :-).guest abuses ptrace permissions on his own processes to write to ANY file open by his processes, whose permissions explicitly allow writing to it. Doesn't it trouble you, that guest's processes still
I repeat: Show me how to gain write access without using /proc, and I'll agree with you. (To recap: While file permissions allow writing, directory permissions do not allow any access at all. guest has open file descriptor for reading. Trouble is that guest can upgrade file descriptor to one that allows writing.) Can we continue on lkml? Pavel -- (english) http://www.livejournal.com/~pavelmachek (cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html
Current thread:
- Re: /proc filesystem allows bypassing directory permissions on Linux, (continued)
- Re: /proc filesystem allows bypassing directory permissions on Linux Pavel Machek (Oct 26)
- Re: /proc filesystem allows bypassing directory permissions on Linux psz (Oct 26)
- Re: /proc filesystem allows bypassing directory permissions on Linux Dan Yefimov (Oct 26)
- Re: /proc filesystem allows bypassing directory permissions on Linux Pavel Machek (Oct 26)
- Re: /proc filesystem allows bypassing directory permissions on Linux psz (Oct 26)
- Re: /proc filesystem allows bypassing directory permissions on Linux Dan Yefimov (Oct 26)
- Re: /proc filesystem allows bypassing directory permissions on Linux Pavel Machek (Oct 26)
- Re: /proc filesystem allows bypassing directory permissions on Linux Dan Yefimov (Oct 26)
- Re: /proc filesystem allows bypassing directory permissions on Linux Pavel Machek (Oct 26)
- Re: /proc filesystem allows bypassing directory permissions on Linux Dan Yefimov (Oct 26)
- Re: /proc filesystem allows bypassing directory permissions on Linux Pavel Machek (Oct 26)
- Re: /proc filesystem allows bypassing directory permissions on Linux Dan Yefimov (Oct 26)
- Re: /proc filesystem allows bypassing directory permissions on Linux Ansgar Wiechers (Oct 26)
- Re: /proc filesystem allows bypassing directory permissions on Linux Derek Martin (Oct 28)
- Re: /proc filesystem allows bypassing directory permissions on Linux CaT (Oct 29)
- Re: /proc filesystem allows bypassing directory permissions on Linux Dan Yefimov (Oct 23)
- Re: /proc filesystem allows bypassing directory permissions on Linux Arturo 'Buanzo' Busleiman (Oct 26)
- Re: /proc filesystem allows bypassing directory permissions on Linux Pavel Machek (Oct 26)
- Re: /proc filesystem allows bypassing directory permissions on Linux Dan Yefimov (Oct 26)
- Re: /proc filesystem allows bypassing directory permissions on Linux Pavel Machek (Oct 26)