From: Eric Biggers <ebiggers@kernel.org>
To: Christoph Hellwig <hch@lst.de>
Cc: David Laight <David.Laight@aculab.com>,
syzbot+51177e4144d764827c45@syzkaller.appspotmail.com,
linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org,
syzkaller-bugs@googlegroups.com, viro@zeniv.linux.org.uk
Subject: Re: WARNING in __kernel_read (2)
Date: Mon, 28 Sep 2020 15:14:41 -0700 [thread overview]
Message-ID: <20200928221441.GF1340@sol.localdomain> (raw)
In-Reply-To: <642ed0b4810d44ab97a7832ccb8b3e44@AcuMS.aculab.com>
On Sat, Sep 26, 2020 at 01:17:04PM +0000, David Laight wrote:
> From: David Laight
> > Sent: 26 September 2020 12:16
> > To: 'syzbot' <syzbot+51177e4144d764827c45@syzkaller.appspotmail.com>; linux-fsdevel@vger.kernel.org;
> > linux-kernel@vger.kernel.org; syzkaller-bugs@googlegroups.com; viro@zeniv.linux.org.uk
> > Subject: RE: WARNING in __kernel_read (2)
> >
> > > From: syzbot <syzbot+51177e4144d764827c45@syzkaller.appspotmail.com>
> > > Sent: 26 September 2020 03:58
> > > To: linux-fsdevel@vger.kernel.org; linux-kernel@vger.kernel.org; syzkaller-bugs@googlegroups.com;
> > > viro@zeniv.linux.org.uk
> > > Subject: WARNING in __kernel_read (2)
> >
> > I suspect this is calling finit_module() on an fd
> > that doesn't have read permissions.
>
> Code inspection also seems to imply that the check means
> the exec() also requires read permissions on the file.
>
> This isn't traditionally true.
> suid #! scripts are particularly odd without 'owner read'
> (everyone except the owner can run them!).
Christoph, any thoughts here? You added this WARN_ON_ONCE in:
commit 61a707c543e2afe3aa7e88f87267c5dafa4b5afa
Author: Christoph Hellwig <hch@lst.de>
Date: Fri May 8 08:54:16 2020 +0200
fs: add a __kernel_read helper
next prev parent reply other threads:[~2020-09-28 23:30 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-09-26 2:58 WARNING in __kernel_read (2) syzbot
2020-09-26 11:15 ` David Laight
2020-09-26 13:17 ` David Laight
2020-09-28 22:14 ` Eric Biggers [this message]
2020-09-29 6:38 ` Christoph Hellwig
2020-09-29 6:46 ` Eric Biggers
2020-09-29 6:56 ` Christoph Hellwig
2020-09-29 8:06 ` David Laight
2020-09-29 8:21 ` Dmitry Vyukov
2020-09-29 10:21 ` Christoph Hellwig
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