From: Pavel Machek <pavel@ucw.cz>
To: kernel list <linux-kernel@vger.kernel.org>, jack@suse.cz
Cc: linux-fsdevel@vger.kernel.org, viro@zeniv.linux.org.uk,
jamie@shareable.org
Subject: symlinks with permissions
Date: Sun, 25 Oct 2009 07:29:53 +0100 [thread overview]
Message-ID: <20091025062953.GC1391@ucw.cz> (raw)
...yes, they do exist, in /proc/self/fd/* . Unfortunately, their
permissions are not actually checked during open, resulting in
(obscure) security hole: if you have fd open for reading, you can
reopen it for write, even through unix permissions would not allow
that.
Now... I'd like to close the hole. One way would be to actually check
symlink permissions on open -- because those symlinks already have
correct permissions.
But ... then I got lost in vfs. Can someone help? Is there better way?
Pavel
--
(english) http://www.livejournal.com/~pavelmachek
(cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html
next reply other threads:[~2009-10-25 19:12 UTC|newest]
Thread overview: 27+ messages / expand[flat|nested] mbox.gz Atom feed top
2009-10-25 6:29 Pavel Machek [this message]
2009-10-26 16:31 ` symlinks with permissions Jan Kara
2009-10-26 16:57 ` Serge E. Hallyn
2009-10-26 17:36 ` J. Bruce Fields
2009-10-26 17:46 ` Jan Kara
2009-10-26 17:57 ` Trond Myklebust
2009-10-25 9:36 ` Pavel Machek
2009-10-26 18:22 ` Trond Myklebust
2009-10-27 8:11 ` Pavel Machek
2009-10-27 10:27 ` Jamie Lokier
2009-10-26 18:35 ` J. Bruce Fields
2009-10-28 4:15 ` Eric W. Biederman
2009-10-28 8:16 ` Pavel Machek
2009-10-28 11:25 ` Eric W. Biederman
2009-10-28 21:03 ` Pavel Machek
2009-10-29 2:20 ` Eric W. Biederman
2009-10-29 11:03 ` Pavel Machek
2009-10-29 16:23 ` Eric W. Biederman
2009-10-30 18:35 ` Pavel Machek
2009-10-30 20:37 ` Nick Bowler
2009-10-30 23:03 ` Eric W. Biederman
2009-10-31 2:30 ` Jamie Lokier
2009-10-28 16:34 ` Casey Schaufler
2009-10-28 19:44 ` Jamie Lokier
2009-10-28 21:06 ` Pavel Machek
2009-10-26 18:02 ` J. Bruce Fields
2009-10-26 17:57 ` Serge E. Hallyn
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=20091025062953.GC1391@ucw.cz \
--to=pavel@ucw.cz \
--cc=jack@suse.cz \
--cc=jamie@shareable.org \
--cc=linux-fsdevel@vger.kernel.org \
--cc=linux-kernel@vger.kernel.org \
--cc=viro@zeniv.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).