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 08:56:01 +0200 [thread overview]
Message-ID: <20200929065601.GA2095@lst.de> (raw)
In-Reply-To: <20200929064648.GA238449@sol.localdomain>
On Mon, Sep 28, 2020 at 11:46:48PM -0700, Eric Biggers wrote:
> > Linus asked for it. What is the call chain that we hit it with?
>
> Call Trace:
> kernel_read+0x52/0x70 fs/read_write.c:471
> kernel_read_file fs/exec.c:989 [inline]
> kernel_read_file+0x2e5/0x620 fs/exec.c:952
> kernel_read_file_from_fd+0x56/0xa0 fs/exec.c:1076
> __do_sys_finit_module+0xe6/0x190 kernel/module.c:4066
> do_syscall_64+0x2d/0x70 arch/x86/entry/common.c:46
> entry_SYSCALL_64_after_hwframe+0x44/0xa9
>
> See the email from syzbot for the full details:
> https://lkml.kernel.org/linux-fsdevel/000000000000da992305b02e9a51@google.com
Passing a fs without read permissions definitively looks bogus for
the finit_module syscall. So I think all we need is an extra check
to validate the fd.
next prev parent reply other threads:[~2020-09-29 6:56 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
2020-09-29 6:46 ` Eric Biggers
2020-09-29 6:56 ` Christoph Hellwig [this message]
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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