From: Trond Myklebust <trond.myklebust@fys.uio.no>
To: Bryan Henderson <hbryan@us.ibm.com>
Cc: Josef Sipek <jsipek@fsl.cs.sunysb.edu>,
dpquigl@tycho.nsa.gov, dquigley@ic.sunysb.edu, ezk@cs.sunysb.edu,
Christoph Hellwig <hch@infradead.org>,
linux-fsdevel@vger.kernel.org, Al Viro <viro@ftp.linux.org.uk>
Subject: Re: [RFC] Privilege escalation in filesystems
Date: Thu, 10 Aug 2006 15:45:19 -0400 [thread overview]
Message-ID: <1155239119.5826.12.camel@localhost> (raw)
In-Reply-To: <OF8632A737.681231B8-ON882571C6.00624D4D-882571C6.006381F5@us.ibm.com>
On Thu, 2006-08-10 at 11:06 -0700, Bryan Henderson wrote:
> What you're describing is not a need to perform operations as another
> user, but a need to perform them with DAC_OVERRIDE capability. In Linux,
> having uid 0 buys you nothing but access to files owned by uid 0.
Sorry, but CAP_DAC_OVERRIDE can, and usually will, be overridden in a
typical selinux environment. That is precisely why we had to abandon
using it for privileged operations such as binding a socket to a
reserved port in the SUNRPC layer in the early 2.6.x days.
Josef, if you really need to do this hidden directory creation (which is
also something which is not supported by all filesystems, BTW - remember
FAT and its 8+3 filenames?) then why not use that as a flag to signal
that the directory is visible to unionfs rather than have it signal
invisibility?
Then leave the whole issue of whether or not to set it to the user.
Cheers,
Trond
next prev parent reply other threads:[~2006-08-10 19:45 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2006-08-09 21:52 [RFC] Privilege escalation in filesystems Josef Sipek
2006-08-09 22:17 ` Trond Myklebust
2006-08-09 22:37 ` Josef Sipek
2006-08-10 18:06 ` Bryan Henderson
2006-08-10 19:29 ` Josef Sipek
2006-08-10 19:45 ` Trond Myklebust [this message]
2006-08-10 20:47 ` Josef Sipek
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=1155239119.5826.12.camel@localhost \
--to=trond.myklebust@fys.uio.no \
--cc=dpquigl@tycho.nsa.gov \
--cc=dquigley@ic.sunysb.edu \
--cc=ezk@cs.sunysb.edu \
--cc=hbryan@us.ibm.com \
--cc=hch@infradead.org \
--cc=jsipek@fsl.cs.sunysb.edu \
--cc=linux-fsdevel@vger.kernel.org \
--cc=viro@ftp.linux.org.uk \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).