Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id B1733C433EF for ; Mon, 6 Dec 2021 16:01:28 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1388628AbhLFQEz (ORCPT ); Mon, 6 Dec 2021 11:04:55 -0500 Received: from dfw.source.kernel.org ([139.178.84.217]:35804 "EHLO dfw.source.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1385729AbhLFP45 (ORCPT ); Mon, 6 Dec 2021 10:56:57 -0500 Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by dfw.source.kernel.org (Postfix) with ESMTPS id 755C9612D3; Mon, 6 Dec 2021 15:53:27 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id A441FC341F8; Mon, 6 Dec 2021 15:53:26 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1638806006; bh=LVzcOfoJv9Y3eoCAXke2gDeYUbUcFGp9/7s2MGxf4ec=; h=Date:From:To:Cc:Subject:In-Reply-To:References:From; b=gWOwEZOYaB1xlh+objmSG7XkvqGq938QSclF5vC7e0gdV+UhpsY9/U3J8aFXgMjUI 7FTtvxlVNuYwZ4kMx1xzZ5sELb646y/B6i2Iw/lXm64mrs93jguTUus2E5En3LZs86 k6+PAhcgSQGvlqDmvhYJQCi/Ld3EVQ2nbFBv7IiqvX14NE/QhlnlKjpVY0LwotOsjW djk1o3bNN5R1AJ6+B7Kwyz23RZvpcSd8Oym2SyGWqVrmCemCwi7aScsjugYRdUgwi6 mpe3KxBipb6a1fZ0ihPEOb2R9xOnAZFOPjetslcONwW9JrzUpB0OpZ+mVGuUTc0YBQ z7JEQF71JZfUg== Date: Mon, 6 Dec 2021 07:53:26 -0800 From: Jakub Kicinski To: Florian Westphal Cc: , syzkaller-bugs@googlegroups.com, , linux-kernel@vger.kernel.org, syzbot+1fd9b69cde42967d1add@syzkaller.appspotmail.com Subject: Re: [PATCH mptcp] mptcp: remove tcp ulp setsockopt support Message-ID: <20211206075326.700f2078@kicinski-fedora-pc1c0hjn.dhcp.thefacebook.com> In-Reply-To: <20211205192700.25396-1-fw@strlen.de> References: <00000000000040972505d24e88e3@google.com> <20211205192700.25396-1-fw@strlen.de> MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Sun, 5 Dec 2021 20:27:00 +0100 Florian Westphal wrote: > TCP_ULP setsockopt cannot be used for mptcp because its already > used internally to plumb subflow (tcp) sockets to the mptcp layer. > > syzbot managed to trigger a crash for mptcp connections that are > in fallback mode: Fallback mode meaning ops are NULL? I'm slightly confused by this report. > KASAN: null-ptr-deref in range [0x0000000000000020-0x0000000000000027] > CPU: 1 PID: 1083 Comm: syz-executor.3 Not tainted 5.16.0-rc2-syzkaller #0 > RIP: 0010:tls_build_proto net/tls/tls_main.c:776 [inline] > [..] > __tcp_set_ulp net/ipv4/tcp_ulp.c:139 [inline] > tcp_set_ulp+0x428/0x4c0 net/ipv4/tcp_ulp.c:160 > do_tcp_setsockopt+0x455/0x37c0 net/ipv4/tcp.c:3391 > mptcp_setsockopt+0x1b47/0x2400 net/mptcp/sockopt.c:638 > > Remove support for TCP_ULP setsockopt. > > Reported-by: syzbot+1fd9b69cde42967d1add@syzkaller.appspotmail.com > Signed-off-by: Florian Westphal