From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-16.1 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,INCLUDES_PATCH,MAILING_LIST_MULTI, SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_GIT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id D8136C43464 for ; Fri, 18 Sep 2020 02:35:44 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 9D76922208 for ; Fri, 18 Sep 2020 02:35:44 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1600396544; bh=Ms8lENlLnFZ6YwfFPHM65qrhWiEu1s7AEcXco8pP22w=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=1ybUC5DGzhkl04y4/juSocxnFs3FwIrrb8jM4wXEDbvlnt9saj/eCdrlDMW1dKR3w +f3K4IsoW4N5Z+0Hzwy0VsSxrODrE+ut6Ic2bDHMxzglaSUgMAXPGAWQ2kqAdR8l6/ HkGR2APv1PTewtGfheMp4FG22pVsq1YzfUm82nvc= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728982AbgIRCfn (ORCPT ); Thu, 17 Sep 2020 22:35:43 -0400 Received: from mail.kernel.org ([198.145.29.99]:39998 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728882AbgIRCNH (ORCPT ); Thu, 17 Sep 2020 22:13:07 -0400 Received: from sasha-vm.mshome.net (c-73-47-72-35.hsd1.nh.comcast.net [73.47.72.35]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 560002388D; Fri, 18 Sep 2020 02:13:06 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1600395187; bh=Ms8lENlLnFZ6YwfFPHM65qrhWiEu1s7AEcXco8pP22w=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=ar4a0FoMD9TlGRNN8aKHIo1TI4K9TybOaqngd2za/hA9E+rq5xIms8aEEgE9kB/sV Xr+xlF/9Jgf270CHnHzLOk5EeVG0Kg87F8DUWvwHGRFxjMhVneESScaQfxBF2AcvlQ sURacDwesSdHRBVQZ+5FNkllgDOD3mlCRJ53S8R4= From: Sasha Levin To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: Hillf Danton , syzbot+c3c5bdea7863886115dc@syzkaller.appspotmail.com, Manish Mandlik , Marcel Holtmann , Sasha Levin , linux-bluetooth@vger.kernel.org, netdev@vger.kernel.org Subject: [PATCH AUTOSEL 4.14 039/127] Bluetooth: prefetch channel before killing sock Date: Thu, 17 Sep 2020 22:10:52 -0400 Message-Id: <20200918021220.2066485-39-sashal@kernel.org> X-Mailer: git-send-email 2.25.1 In-Reply-To: <20200918021220.2066485-1-sashal@kernel.org> References: <20200918021220.2066485-1-sashal@kernel.org> MIME-Version: 1.0 X-stable: review X-Patchwork-Hint: Ignore Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org From: Hillf Danton [ Upstream commit 2a154903cec20fb64ff4d7d617ca53c16f8fd53a ] Prefetch channel before killing sock in order to fix UAF like BUG: KASAN: use-after-free in l2cap_sock_release+0x24c/0x290 net/bluetooth/l2cap_sock.c:1212 Read of size 8 at addr ffff8880944904a0 by task syz-fuzzer/9751 Reported-by: syzbot+c3c5bdea7863886115dc@syzkaller.appspotmail.com Fixes: 6c08fc896b60 ("Bluetooth: Fix refcount use-after-free issue") Cc: Manish Mandlik Signed-off-by: Hillf Danton Signed-off-by: Marcel Holtmann Signed-off-by: Sasha Levin --- net/bluetooth/l2cap_sock.c | 10 ++++++---- 1 file changed, 6 insertions(+), 4 deletions(-) diff --git a/net/bluetooth/l2cap_sock.c b/net/bluetooth/l2cap_sock.c index a5e618add17f4..511a1da6ca971 100644 --- a/net/bluetooth/l2cap_sock.c +++ b/net/bluetooth/l2cap_sock.c @@ -1191,6 +1191,7 @@ static int l2cap_sock_release(struct socket *sock) { struct sock *sk = sock->sk; int err; + struct l2cap_chan *chan; BT_DBG("sock %p, sk %p", sock, sk); @@ -1200,15 +1201,16 @@ static int l2cap_sock_release(struct socket *sock) bt_sock_unlink(&l2cap_sk_list, sk); err = l2cap_sock_shutdown(sock, 2); + chan = l2cap_pi(sk)->chan; - l2cap_chan_hold(l2cap_pi(sk)->chan); - l2cap_chan_lock(l2cap_pi(sk)->chan); + l2cap_chan_hold(chan); + l2cap_chan_lock(chan); sock_orphan(sk); l2cap_sock_kill(sk); - l2cap_chan_unlock(l2cap_pi(sk)->chan); - l2cap_chan_put(l2cap_pi(sk)->chan); + l2cap_chan_unlock(chan); + l2cap_chan_put(chan); return err; } -- 2.25.1