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=unavailable 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 D7E32C43466 for ; Fri, 18 Sep 2020 02:15:38 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id A8737208DB for ; Fri, 18 Sep 2020 02:15:38 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1600395338; bh=73XmBbL5kBfw8v5hmI7Y6kgq/EvxjfR/wQnjwChQaPc=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=AGwQjlrJf7O4wXjdNhXkxz4rfgUz/mC8uU5vjmeac8G52m5tY/KMGM2qPmfFEtDi4 NFYFolcOVnjvifD61GTDRfCzjr8Ta3pJb22P3O+Kx6eh2B42EmDTy1G4ATazqWbPfh nERoR3G6XunXZu2lxziUWfKq5TwU8LDxFmB0L37U= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729268AbgIRCPh (ORCPT ); Thu, 17 Sep 2020 22:15:37 -0400 Received: from mail.kernel.org ([198.145.29.99]:44486 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728540AbgIRCPd (ORCPT ); Thu, 17 Sep 2020 22:15:33 -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 ED1A823718; Fri, 18 Sep 2020 02:15:31 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1600395332; bh=73XmBbL5kBfw8v5hmI7Y6kgq/EvxjfR/wQnjwChQaPc=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=Gz3fagPOzgarUo2LQ9tx1SVy3OMzPTFJR/SuFl0Oz/2+xiGyEXdD00GzVaHFnHrSJ xZNgn310hULGDBx5a3oHBjHb58mgK/Cex8P6Sy8ax5ivYBOWolVlcU5bMBtfX/DTH4 AcFCQmS32wki2Ez8gZkGoH4zdchgKFbqIAi8HDZM= 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 4.9 30/90] Bluetooth: prefetch channel before killing sock Date: Thu, 17 Sep 2020 22:13:55 -0400 Message-Id: <20200918021455.2067301-30-sashal@kernel.org> X-Mailer: git-send-email 2.25.1 In-Reply-To: <20200918021455.2067301-1-sashal@kernel.org> References: <20200918021455.2067301-1-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: linux-kernel@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 3db8cfebd069a..bbf08c6092f4a 100644 --- a/net/bluetooth/l2cap_sock.c +++ b/net/bluetooth/l2cap_sock.c @@ -1189,6 +1189,7 @@ 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); @@ -1198,15 +1199,16 @@ 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