linux-security-module.vger.kernel.org archive mirror
 help / color / mirror / Atom feed
From: Al Viro <viro@zeniv.linux.org.uk>
To: Tetsuo Handa <penguin-kernel@i-love.sakura.ne.jp>
Cc: linux-fsdevel@vger.kernel.org,
	syzbot <syzbot+0341f6a4d729d4e0acf1@syzkaller.appspotmail.com>,
	jmorris@namei.org, linux-kernel@vger.kernel.org,
	linux-security-module@vger.kernel.org, serge@hallyn.com,
	syzkaller-bugs@googlegroups.com, takedakn@nttdata.co.jp,
	"David S. Miller" <davem@davemloft.net>
Subject: Re: [PATCH] tomoyo: Don't check open/getattr permission on sockets.
Date: Tue, 18 Jun 2019 21:49:33 +0100	[thread overview]
Message-ID: <20190618204933.GE17978@ZenIV.linux.org.uk> (raw)
In-Reply-To: <a4ed1778-8b73-49d1-0ff0-59d9c6ac0af8@I-love.SAKURA.ne.jp>

On Sun, Jun 16, 2019 at 03:49:00PM +0900, Tetsuo Handa wrote:
> Hello, Al.
> 
> Q1: Do you agree that we should fix TOMOYO side rather than SOCKET_I()->sk
>     management.

You do realize that sockets are not unique in that respect, right?
All kinds of interesting stuff can be accessed via /proc/*/fd/*, and
it _can_ be closed under you.  So I'd suggest checking how your code
copes with similar for pipes, FIFOs, epoll, etc., accessed that way...

We are _not_ going to be checking that in fs/open.c - the stuff found
via /proc/*/fd/* can have the associated file closed by the time
we get to calling ->open() and we won't know that until said call.

> Q2: Do you see any problem with using f->f_path.dentry->d_inode ?
>     Do we need to use d_backing_inode() or d_inode() ?

Huh?  What's wrong with file_inode(f), in the first place?  And
just when can that be NULL, while we are at it?

> >  static int tomoyo_inode_getattr(const struct path *path)
> >  {
> > +	/* It is not safe to call tomoyo_get_socket_name(). */
> > +	if (path->dentry->d_inode && S_ISSOCK(path->dentry->d_inode->i_mode))
> > +		return 0;

Can that be called for a negative?

  reply	other threads:[~2019-06-18 20:49 UTC|newest]

Thread overview: 32+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-06-05 18:42 KASAN: use-after-free Read in tomoyo_realpath_from_path syzbot
2019-06-05 22:09 ` Tetsuo Handa
2019-06-06  2:08 ` Tetsuo Handa
2019-06-06  5:20 ` Tetsuo Handa
2019-06-09  6:41   ` [PATCH] tomoyo: Don't check open/getattr permission on sockets Tetsuo Handa
2019-06-16  6:49     ` Tetsuo Handa
2019-06-18 20:49       ` Al Viro [this message]
2019-06-22  4:45         ` [PATCH v2] " Tetsuo Handa
2019-07-04 11:58           ` Tetsuo Handa
2019-07-07  2:44             ` James Morris
2019-07-07  2:50               ` James Morris
2019-08-09 15:51                 ` Tetsuo Handa
2019-09-03  6:52                 ` Tetsuo Handa
2019-09-13 13:41                   ` Tetsuo Handa
     [not found]                     ` <A9CE5147-4047-4C42-B772-F0ED510FA283@canb.auug.org.au>
2019-10-02 10:50                       ` Tetsuo Handa
2019-10-02 22:25                         ` Stephen Rothwell
2019-10-03  9:59                           ` Tetsuo Handa
2019-11-13 13:49                             ` Tetsuo Handa
2019-11-21  7:21                               ` James Morris
2019-11-21 10:18                                 ` Tetsuo Handa
2019-11-21 13:59                                   ` Tetsuo Handa
2019-12-04 12:50                                     ` Tetsuo Handa
2019-12-09 21:37                                       ` James Morris
2019-12-10 10:21                                         ` Tetsuo Handa
2019-12-10 23:02                                           ` Stephen Rothwell
2019-12-11 11:19                                             ` Tetsuo Handa
2019-10-02 22:22                     ` Stephen Rothwell
2019-08-22  6:30           ` Eric Biggers
2019-08-22  6:55             ` Tetsuo Handa
2019-08-22  7:01               ` Eric Biggers
2019-08-22  7:42                 ` Tetsuo Handa
2019-08-22 15:47                   ` Eric Biggers

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=20190618204933.GE17978@ZenIV.linux.org.uk \
    --to=viro@zeniv.linux.org.uk \
    --cc=davem@davemloft.net \
    --cc=jmorris@namei.org \
    --cc=linux-fsdevel@vger.kernel.org \
    --cc=linux-kernel@vger.kernel.org \
    --cc=linux-security-module@vger.kernel.org \
    --cc=penguin-kernel@i-love.sakura.ne.jp \
    --cc=serge@hallyn.com \
    --cc=syzbot+0341f6a4d729d4e0acf1@syzkaller.appspotmail.com \
    --cc=syzkaller-bugs@googlegroups.com \
    --cc=takedakn@nttdata.co.jp \
    /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).