From patchwork Mon Jan 18 11:34:49 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Greg KH X-Patchwork-Id: 366946 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 34F4AC433E0 for ; Mon, 18 Jan 2021 11:38:22 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id DC1B022CA1 for ; Mon, 18 Jan 2021 11:38:21 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2390446AbhARLiS (ORCPT ); Mon, 18 Jan 2021 06:38:18 -0500 Received: from mail.kernel.org ([198.145.29.99]:34044 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2390425AbhARLiH (ORCPT ); Mon, 18 Jan 2021 06:38:07 -0500 Received: by mail.kernel.org (Postfix) with ESMTPSA id 499C4229F0; Mon, 18 Jan 2021 11:36:28 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1610969788; bh=LRsymFWRyAlciZDqiRWK/ntSKv42t36TUPbsZRWPdvQ=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=D9uB1PEjIltD9R6Ambssdgj2bLkagmI9UEjosfso8m7c7rv8DgnKFO4uVCnGH+aWm gfd5l4WnAiU7p9BACHILsOc2+a9sJg+ylj+XO386/dis/6rDO78/65zwTjKUBG+ngi bXZnDztstB5PAAShOvjqApAUH5NqVitCD7gPPTCc= 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 4.19 26/43] dump_common_audit_data(): fix racy accesses to ->d_name Date: Mon, 18 Jan 2021 12:34:49 +0100 Message-Id: <20210118113336.208080694@linuxfoundation.org> X-Mailer: git-send-email 2.30.0 In-Reply-To: <20210118113334.966227881@linuxfoundation.org> References: <20210118113334.966227881@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 @@ -277,7 +277,9 @@ 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) { @@ -295,8 +297,9 @@ 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=");