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=ham 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 D172DC432C0 for ; Wed, 27 Nov 2019 21:33:35 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 9D8DA206F0 for ; Wed, 27 Nov 2019 21:33:35 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1574890415; bh=XRbu216x41VlCbMrwQejgg8e7awRwMdwlAm6BBlFN/k=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=O8SoymAxRL5AzJxMgUwI1sqSC7H8AkqNOpJEo3SH5tnQ+RlO86+t+qhzw9ffZv59b hbALzclAGIKUFYYKP3emvYCl5js1dJMIoSFXU7YpkYA9NO5+2sDV8sCbtlZiSiJobm 2AzHqaN6mfrxBanhsInkFmo/rkuEfxicBheLvgt0= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729372AbfK0UwH (ORCPT ); Wed, 27 Nov 2019 15:52:07 -0500 Received: from mail.kernel.org ([198.145.29.99]:39308 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728360AbfK0UwF (ORCPT ); Wed, 27 Nov 2019 15:52:05 -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 76B0F218AE; Wed, 27 Nov 2019 20:52:03 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1574887923; bh=XRbu216x41VlCbMrwQejgg8e7awRwMdwlAm6BBlFN/k=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=vdDcwJu/4pp2p9N4o1QK7rEvnWtcGuXEcOUZkbtoPOup4QR32GHxDN9u1fSIThp6v Vl8DBQbzusB6Q2LmsRAyZ7HylI44fRkR7P2a7Lcx9eKY2nDqAeAMPHI5uoJwWdW/ml fI8HYWcl96BTOJUGVOCICQtre8wqZeLeFWi2mcy4= 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 4.14 148/211] dlm: dont leak kernel pointer to userspace Date: Wed, 27 Nov 2019 21:31:21 +0100 Message-Id: <20191127203108.000787142@linuxfoundation.org> X-Mailer: git-send-email 2.24.0 In-Reply-To: <20191127203049.431810767@linuxfoundation.org> References: <20191127203049.431810767@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: 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 d18e7a539f116..1f0c071d4a861 100644 --- a/fs/dlm/user.c +++ b/fs/dlm/user.c @@ -702,7 +702,7 @@ 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