linux-kernel - Re: [PATCH] vfs: new O

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <20090928141025.GF19778@shareable.org>
Date:	Mon, 28 Sep 2009 15:10:25 +0100
From:	Jamie Lokier <jamie@...reable.org>
To:	Miklos Szeredi <miklos@...redi.hu>
Cc:	Valdis.Kletnieks@...edu, linux@...blig.org, agruen@...e.de,
	linux-fsdevel@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH] vfs: new O_NODE open flag

Miklos Szeredi wrote:
> > Hmm.  I have just tried, and you _can _use open("/proc/self/fd/%d",
> > O_RDWR) to re-open with more permissions when you can't access the
> > path which /proc/self/fd/%d pretends to link to.  It looks a bit
> > dubious, as you might have been passed an O_RDONLY descriptor with the
> > intention that you can't write to it...  Oh well!
> 
> True, /proc gives you access to the underlying "path" of an open file
> descriptor.  If you don't want that, don't mount /proc in your limited
> namespace.

I wasn't using a limited namespace.

Just a directory without permission to be searched, and as a regular
user - which is historically supposed to prevent you from opening
files in it.

-- Jamie
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/