From patchwork Mon Jan 18 11:34:50 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Greg Kroah-Hartman X-Patchwork-Id: 366094 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=-18.8 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID, DKIM_VALID_AU, HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_CR_TRAILER, INCLUDES_PATCH, MAILING_LIST_MULTI, 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 5E6B7C433E0 for ; Mon, 18 Jan 2021 11:40:10 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 15A4F22227 for ; Mon, 18 Jan 2021 11:40:10 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2390588AbhARLjx (ORCPT ); Mon, 18 Jan 2021 06:39:53 -0500 Received: from mail.kernel.org ([198.145.29.99]:35674 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2390582AbhARLjv (ORCPT ); Mon, 18 Jan 2021 06:39:51 -0500 Received: by mail.kernel.org (Postfix) with ESMTPSA id 05FDF229F0; Mon, 18 Jan 2021 11:39:09 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1610969950; bh=uiFtAoy1X5FbQVW0lmtDN1898APkv7jDRkAxircn1FE=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=eA/QThyGByu3e6KIrcMzWDJX1PMB0MPQsmoqQXPFyeJvetSQqxwmNepNR7bhUmaKh biWQyp4D+qsRnWOmajtxTIerKdsdQgZkA174mQtTWtn6sKVF15rxIB5ozFgl7C7ws1 tEihnj9XqVavnYqiB+OV3UTSa7ghR3fMwROWCv3g= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Al Viro , stable@kernel.org Subject: [PATCH 5.4 50/76] dump_common_audit_data(): fix racy accesses to ->d_name Date: Mon, 18 Jan 2021 12:34:50 +0100 Message-Id: <20210118113343.381925098@linuxfoundation.org> X-Mailer: git-send-email 2.30.0 In-Reply-To: <20210118113340.984217512@linuxfoundation.org> References: <20210118113340.984217512@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org From: Al Viro commit d36a1dd9f77ae1e72da48f4123ed35627848507d upstream. We are not guaranteed the locking environment that would prevent dentry getting renamed right under us. And it's possible for old long name to be freed after rename, leading to UAF here. Cc: stable@kernel.org # v2.6.2+ Signed-off-by: Al Viro Signed-off-by: Greg Kroah-Hartman --- security/lsm_audit.c | 7 +++++-- 1 file changed, 5 insertions(+), 2 deletions(-) --- a/security/lsm_audit.c +++ b/security/lsm_audit.c @@ -274,7 +274,9 @@ static void dump_common_audit_data(struc struct inode *inode; audit_log_format(ab, " name="); + spin_lock(&a->u.dentry->d_lock); audit_log_untrustedstring(ab, a->u.dentry->d_name.name); + spin_unlock(&a->u.dentry->d_lock); inode = d_backing_inode(a->u.dentry); if (inode) { @@ -292,8 +294,9 @@ static void dump_common_audit_data(struc dentry = d_find_alias(inode); if (dentry) { audit_log_format(ab, " name="); - audit_log_untrustedstring(ab, - dentry->d_name.name); + spin_lock(&dentry->d_lock); + audit_log_untrustedstring(ab, dentry->d_name.name); + spin_unlock(&dentry->d_lock); dput(dentry); } audit_log_format(ab, " dev=");