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=-6.8 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,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 2E7F1C3524F for ; Mon, 3 Feb 2020 16:44:21 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id F00DA20838 for ; Mon, 3 Feb 2020 16:44:20 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1580748261; bh=rcQDecP37dL91YXleyWQRqGSr0A+L9q6Ie3Ao5CUXLY=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=Y2haIW4WOWzUt+mrzRATNkemOdbUoq7oqNsfy1ByZ2vFzM6gVlAnxzro6G+Zi23+T JM5cUwjCqnMCLGsq70wRo/dMVKBfCT3qS0L4ZpjPj1xG0nzSg7ylhl7UHE+dtOzplK u5aAK5W80DrPjHMPvV8PF3UQ25mfCE1w3UC2RMsQ= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1730294AbgBCQbs (ORCPT ); Mon, 3 Feb 2020 11:31:48 -0500 Received: from mail.kernel.org ([198.145.29.99]:45142 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729925AbgBCQbo (ORCPT ); Mon, 3 Feb 2020 11:31:44 -0500 Received: from localhost (unknown [104.132.45.99]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id C88CF20CC7; Mon, 3 Feb 2020 16:31:43 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1580747504; bh=rcQDecP37dL91YXleyWQRqGSr0A+L9q6Ie3Ao5CUXLY=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=Lj5JAoUXAQGvLJia5cUwpeeqqOZ2Yl+7EvCFOpFdITCQIjjmCMwK1Pm2RBo5JrT4P IEP5VLPUqlpj9uUkUIiEI9UBXzoT0j8wx9P+FzCr92rYXqg2kzQ1lj8tXTlBox8FTc b6X08lAs18XpEcJY5Lt0xgClpZ8bhUsVORoQ0xWw= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, syzbot+eba992608adf3d796bcc@syzkaller.appspotmail.com, Dan Carpenter , Johan Hedberg Subject: [PATCH 4.19 22/70] Bluetooth: Fix race condition in hci_release_sock() Date: Mon, 3 Feb 2020 16:19:34 +0000 Message-Id: <20200203161915.832501957@linuxfoundation.org> X-Mailer: git-send-email 2.25.0 In-Reply-To: <20200203161912.158976871@linuxfoundation.org> References: <20200203161912.158976871@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Dan Carpenter commit 11eb85ec42dc8c7a7ec519b90ccf2eeae9409de8 upstream. Syzbot managed to trigger a use after free "KASAN: use-after-free Write in hci_sock_bind". I have reviewed the code manually and one possibly cause I have found is that we are not holding lock_sock(sk) when we do the hci_dev_put(hdev) in hci_sock_release(). My theory is that the bind and the release are racing against each other which results in this use after free. Reported-by: syzbot+eba992608adf3d796bcc@syzkaller.appspotmail.com Signed-off-by: Dan Carpenter Signed-off-by: Johan Hedberg Signed-off-by: Greg Kroah-Hartman --- net/bluetooth/hci_sock.c | 3 +++ 1 file changed, 3 insertions(+) --- a/net/bluetooth/hci_sock.c +++ b/net/bluetooth/hci_sock.c @@ -831,6 +831,8 @@ static int hci_sock_release(struct socke if (!sk) return 0; + lock_sock(sk); + switch (hci_pi(sk)->channel) { case HCI_CHANNEL_MONITOR: atomic_dec(&monitor_promisc); @@ -878,6 +880,7 @@ static int hci_sock_release(struct socke skb_queue_purge(&sk->sk_receive_queue); skb_queue_purge(&sk->sk_write_queue); + release_sock(sk); sock_put(sk); return 0; }