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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 9D0A8C433EF for ; Mon, 21 Feb 2022 08:59:36 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1346765AbiBUI74 (ORCPT ); Mon, 21 Feb 2022 03:59:56 -0500 Received: from mxb-00190b01.gslb.pphosted.com ([23.128.96.19]:59280 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1346895AbiBUI72 (ORCPT ); Mon, 21 Feb 2022 03:59:28 -0500 Received: from dfw.source.kernel.org (dfw.source.kernel.org [IPv6:2604:1380:4641:c500::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 2480326128; Mon, 21 Feb 2022 00:55:08 -0800 (PST) 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 8E2F36112B; Mon, 21 Feb 2022 08:55:07 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 748F5C340E9; Mon, 21 Feb 2022 08:55:06 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1645433707; bh=IbxYndShaUN1LdttA6NiRREW3GWMiaYelf0xxIh24h0=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=Rca1V6MZb7+jWqmQSvHz0QP1u/4BFR1p85IpUl3HSpvKwn7qM1gY8UTM8/uTUpd8c LBaYuhzD7VBUPStZLz3//XBORfnRXPVBjNxPK98TFd8mqrf7B8mZS2Uk22eLR8j9wq YPQgYCCN8Ci+sKmh7OkDYbEwj4pgYtstEBO3jBKs= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Sagi Grimberg , Sasha Levin Subject: [PATCH 4.19 14/58] nvme: fix a possible use-after-free in controller reset during load Date: Mon, 21 Feb 2022 09:49:07 +0100 Message-Id: <20220221084912.351863300@linuxfoundation.org> X-Mailer: git-send-email 2.35.1 In-Reply-To: <20220221084911.895146879@linuxfoundation.org> References: <20220221084911.895146879@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Sagi Grimberg [ Upstream commit 0fa0f99fc84e41057cbdd2efbfe91c6b2f47dd9d ] Unlike .queue_rq, in .submit_async_event drivers may not check the ctrl readiness for AER submission. This may lead to a use-after-free condition that was observed with nvme-tcp. The race condition may happen in the following scenario: 1. driver executes its reset_ctrl_work 2. -> nvme_stop_ctrl - flushes ctrl async_event_work 3. ctrl sends AEN which is received by the host, which in turn schedules AEN handling 4. teardown admin queue (which releases the queue socket) 5. AEN processed, submits another AER, calling the driver to submit 6. driver attempts to send the cmd ==> use-after-free In order to fix that, add ctrl state check to validate the ctrl is actually able to accept the AER submission. This addresses the above race in controller resets because the driver during teardown should: 1. change ctrl state to RESETTING 2. flush async_event_work (as well as other async work elements) So after 1,2, any other AER command will find the ctrl state to be RESETTING and bail out without submitting the AER. Signed-off-by: Sagi Grimberg Signed-off-by: Sasha Levin --- drivers/nvme/host/core.c | 9 ++++++++- 1 file changed, 8 insertions(+), 1 deletion(-) diff --git a/drivers/nvme/host/core.c b/drivers/nvme/host/core.c index e64310f2296f8..a0a805a5ab6b2 100644 --- a/drivers/nvme/host/core.c +++ b/drivers/nvme/host/core.c @@ -3463,7 +3463,14 @@ static void nvme_async_event_work(struct work_struct *work) container_of(work, struct nvme_ctrl, async_event_work); nvme_aen_uevent(ctrl); - ctrl->ops->submit_async_event(ctrl); + + /* + * The transport drivers must guarantee AER submission here is safe by + * flushing ctrl async_event_work after changing the controller state + * from LIVE and before freeing the admin queue. + */ + if (ctrl->state == NVME_CTRL_LIVE) + ctrl->ops->submit_async_event(ctrl); } static bool nvme_ctrl_pp_status(struct nvme_ctrl *ctrl) -- 2.34.1