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=-9.8 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,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 B677CC432C3 for ; Wed, 27 Nov 2019 21:39:54 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 83EB62075C for ; Wed, 27 Nov 2019 21:39:54 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1574890794; bh=5Z8syyPxu+RIe5Hu9MJdInqhpQxBkHwU4Q6mZlg2V8w=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=sIqzrvOisReIc1OkULyDrvI+vaXiYH5AL7rFkYTwu3fJIm51ME7YZL6L6BWPLEIZQ C8SPLr3wsDOdOkY4sKOnSjhqeoPyQQ7eHDPhjroboKTIkytbg6eTlsIzeg0BZ8y8EH HLhHbiMT8IAu1FhUeqyWDBfSCbwKbVshkCUv6nkU= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726703AbfK0Unf (ORCPT ); Wed, 27 Nov 2019 15:43:35 -0500 Received: from mail.kernel.org ([198.145.29.99]:51566 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729470AbfK0Une (ORCPT ); Wed, 27 Nov 2019 15:43:34 -0500 Received: from localhost (83-86-89-107.cable.dynamic.v4.ziggo.nl [83.86.89.107]) (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 120DF217D7; Wed, 27 Nov 2019 20:43:32 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1574887413; bh=5Z8syyPxu+RIe5Hu9MJdInqhpQxBkHwU4Q6mZlg2V8w=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=mYjHONjm4PC1Z/dJYnt40OrmJcOXLEG9mbauVSFEd3HA5S6LSVXP/Qx39AJf7rfee GdMNAYb5au4cU8WGDMFhd9SRamEZOqxtzIBkNpeqAdnShtdEvX7DLZ1AGRpAloHwKF N+wVFwoMZuOXXv5bZ12GZtl44B3adx2nZ/4XSozs= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Tycho Andersen , David Teigland , Sasha Levin Subject: [PATCH 4.9 100/151] dlm: dont leak kernel pointer to userspace Date: Wed, 27 Nov 2019 21:31:23 +0100 Message-Id: <20191127203039.370564169@linuxfoundation.org> X-Mailer: git-send-email 2.24.0 In-Reply-To: <20191127203000.773542911@linuxfoundation.org> References: <20191127203000.773542911@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Sender: stable-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org From: Tycho Andersen [ Upstream commit 9de30f3f7f4d31037cfbb7c787e1089c1944b3a7 ] In copy_result_to_user(), we first create a struct dlm_lock_result, which contains a struct dlm_lksb, the last member of which is a pointer to the lvb. Unfortunately, we copy the entire struct dlm_lksb to the result struct, which is then copied to userspace at the end of the function, leaking the contents of sb_lvbptr, which is a valid kernel pointer in some cases (indeed, later in the same function the data it points to is copied to userspace). It is an error to leak kernel pointers to userspace, as it undermines KASLR protections (see e.g. 65eea8edc31 ("floppy: Do not copy a kernel pointer to user memory in FDGETPRM ioctl") for another example of this). Signed-off-by: Tycho Andersen Signed-off-by: David Teigland Signed-off-by: Sasha Levin --- fs/dlm/user.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/fs/dlm/user.c b/fs/dlm/user.c index 9ac65914ab5b0..57f2aacec97f5 100644 --- a/fs/dlm/user.c +++ b/fs/dlm/user.c @@ -700,7 +700,7 @@ static int copy_result_to_user(struct dlm_user_args *ua, int compat, result.version[0] = DLM_DEVICE_VERSION_MAJOR; result.version[1] = DLM_DEVICE_VERSION_MINOR; result.version[2] = DLM_DEVICE_VERSION_PATCH; - memcpy(&result.lksb, &ua->lksb, sizeof(struct dlm_lksb)); + memcpy(&result.lksb, &ua->lksb, offsetof(struct dlm_lksb, sb_lvbptr)); result.user_lksb = ua->user_lksb; /* FIXME: dlm1 provides for the user's bastparam/addr to not be updated -- 2.20.1