From: Christoph Hellwig <hch@lst.de>
To: Eric Biggers <ebiggers@kernel.org>
Cc: Christoph Hellwig <hch@lst.de>,
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: Tue, 29 Sep 2020 08:38:15 +0200 [thread overview]
Message-ID: <20200929063815.GB1839@lst.de> (raw)
In-Reply-To: <20200928221441.GF1340@sol.localdomain>
On Mon, Sep 28, 2020 at 03:14:41PM -0700, Eric Biggers wrote:
> 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
Linus asked for it. What is the call chain that we hit it with?
next prev parent reply other threads:[~2020-09-29 6:38 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
2020-09-29 6:38 ` Christoph Hellwig [this message]
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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