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 EEAD1C77B75 for ; Mon, 8 May 2023 10:23:39 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S234542AbjEHKXi (ORCPT ); Mon, 8 May 2023 06:23:38 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:50180 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S234461AbjEHKXA (ORCPT ); Mon, 8 May 2023 06:23:00 -0400 Received: from dfw.source.kernel.org (dfw.source.kernel.org [139.178.84.217]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 27FB826470 for ; Mon, 8 May 2023 03:22:46 -0700 (PDT) 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 B3CF562567 for ; Mon, 8 May 2023 10:22:45 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 90E87C4339B; Mon, 8 May 2023 10:22:44 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1683541365; bh=wLtQqlvpw56+8x2JhP757xkkBKJEtgWxzFXJVVzaEIk=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=cMiMl1ZZ4NNqcY9G3v7g5chIjMp4yeJhZbUg8agBTPDG97i6Sq8pMnH6Bzarw/8TG uTl/yJecL+asbaWVteCTEfdnSZXeMM6W1JaogO3E+kcaOxk8/HOqoBJ4oNGBdAfJpf boaxIItbV6e0DueoIB/L9cOQei15mKJuE7I1emIg= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Namjae Jeon , Steve French , zdi-disclosures@trendmicro.com Subject: [PATCH 6.2 091/663] ksmbd: call rcu_barrier() in ksmbd_server_exit() Date: Mon, 8 May 2023 11:38:37 +0200 Message-Id: <20230508094431.413183059@linuxfoundation.org> X-Mailer: git-send-email 2.40.1 In-Reply-To: <20230508094428.384831245@linuxfoundation.org> References: <20230508094428.384831245@linuxfoundation.org> User-Agent: quilt/0.67 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org From: Namjae Jeon commit eb307d09fe15844fdaebeb8cc8c9b9e925430aa5 upstream. racy issue is triggered the bug by racing between closing a connection and rmmod. In ksmbd, rcu_barrier() is not called at module unload time, so nothing prevents ksmbd from getting unloaded while it still has RCU callbacks pending. It leads to trigger unintended execution of kernel code locally and use to defeat protections such as Kernel Lockdown Cc: stable@vger.kernel.org Reported-by: zdi-disclosures@trendmicro.com # ZDI-CAN-20477 Signed-off-by: Namjae Jeon Signed-off-by: Steve French Signed-off-by: Greg Kroah-Hartman --- fs/ksmbd/server.c | 1 + 1 file changed, 1 insertion(+) --- a/fs/ksmbd/server.c +++ b/fs/ksmbd/server.c @@ -606,6 +606,7 @@ err_unregister: static void __exit ksmbd_server_exit(void) { ksmbd_server_shutdown(); + rcu_barrier(); ksmbd_release_inode_hash(); }