From: Al Viro <viro@ftp.linux.org.uk>
To: Ulrich Drepper <drepper@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>,
Markus Trippelsdorf <markus@trippelsdorf.de>,
Andrew Morton <akpm@linux-foundation.org>,
linux-kernel@vger.kernel.org
Subject: Re: 2.6.22-rc6(mm1) Unable to handle kernel NULL pointer dereference - git-bisect result
Date: Sun, 8 Jul 2007 19:31:12 +0100 [thread overview]
Message-ID: <20070708183112.GJ21668@ftp.linux.org.uk> (raw)
In-Reply-To: <46912BF5.8080201@redhat.com>
On Sun, Jul 08, 2007 at 11:24:53AM -0700, Ulrich Drepper wrote:
> -----BEGIN PGP SIGNED MESSAGE-----
> Hash: SHA1
>
> Linus Torvalds wrote:
> > notify_change() does *not* do permission checks for
> > ATTR_CTIME/MTIME/ATIME.
>
> Then I don't understand
>
> /* Check for setting the inode time. */
> if (ia_valid & (ATTR_MTIME_SET | ATTR_ATIME_SET)) {
> if (current->fsuid != inode->i_uid && !capable(CAP_FOWNER))
> goto error;
> }
>
> in inode_change_ok. This seems to me exactly like the check needed.
Sigh... There are two operations.
1) set the timestamp to user-supplied value. Owner-only.
2) have the timestamp set to _now_. Obviously can be done not
only by the owner (think of e.g. write(2)); having write access is
sufficient.
ATTR_MTIME_SET is the former. ATTR_MTIME without ATTR_MTIME_SET is the
latter and that's what utimes(foo, NULL) ends up doing.
next prev parent reply other threads:[~2007-07-08 18:31 UTC|newest]
Thread overview: 21+ messages / expand[flat|nested] mbox.gz Atom feed top
2007-07-08 5:14 2.6.22-rc6-mm1-cfs-v19 Unable to handle kernel NULL pointer dereference (reproducable) Markus Trippelsdorf
2007-07-08 8:20 ` Andrew Morton
2007-07-08 10:09 ` Markus Trippelsdorf
2007-07-08 15:28 ` 2.6.22-rc6(mm1) Unable to handle kernel NULL pointer dereference - git-bisect result Markus Trippelsdorf
2007-07-08 17:02 ` Linus Torvalds
2007-07-08 17:06 ` Ulrich Drepper
2007-07-08 17:33 ` Markus Trippelsdorf
2007-07-08 17:34 ` Al Viro
2007-07-08 17:41 ` Ulrich Drepper
2007-07-08 18:12 ` Linus Torvalds
2007-07-08 18:24 ` Ulrich Drepper
2007-07-08 18:31 ` Al Viro [this message]
2007-07-08 18:40 ` Linus Torvalds
2007-07-08 18:30 ` Linus Torvalds
2007-07-08 18:34 ` Al Viro
2007-07-08 18:38 ` Linus Torvalds
2007-07-08 18:51 ` Al Viro
2007-07-08 19:00 ` Linus Torvalds
2007-07-08 19:26 ` Al Viro
2007-07-08 18:19 ` Al Viro
2007-07-09 12:40 ` 2.6.22-rc6-mm1-cfs-v19 Unable to handle kernel NULL pointer dereference (reproducable) Lenar Lõhmus
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