From patchwork Mon Dec 28 12:47:19 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Greg KH X-Patchwork-Id: 354427 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, 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 A1A9DC433E0 for ; Mon, 28 Dec 2020 16:07:05 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 7ADE9207C9 for ; Mon, 28 Dec 2020 16:07:05 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2389007AbgL1QGt (ORCPT ); Mon, 28 Dec 2020 11:06:49 -0500 Received: from mail.kernel.org ([198.145.29.99]:55328 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2389494AbgL1N0b (ORCPT ); Mon, 28 Dec 2020 08:26:31 -0500 Received: by mail.kernel.org (Postfix) with ESMTPSA id A374220728; Mon, 28 Dec 2020 13:25:49 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1609161950; bh=L29C2rA1dyuGhtjDbgne65PWnPns4sq593oj4UkwEus=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=PPdglN8uye48WLxSPZnGliE5Oj3ClnkCdi+SuTE52hqObMeYLp3gkkYA6utxBF2vP GQQJHbPE0GrpJ9Qp+9GDNfXN/53aQfOovQtAU3CyOtf7renvDcl05wuZFy8eqKZ6TS NjSEhNhx8wgIOrCJfsrxKeKijxwOZ9NiHnCHAZro= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Sven Schnelle , Ondrej Mosnacek , Paul Moore , Sasha Levin Subject: [PATCH 4.19 120/346] selinux: fix inode_doinit_with_dentry() LABEL_INVALID error handling Date: Mon, 28 Dec 2020 13:47:19 +0100 Message-Id: <20201228124925.596058220@linuxfoundation.org> X-Mailer: git-send-email 2.29.2 In-Reply-To: <20201228124919.745526410@linuxfoundation.org> References: <20201228124919.745526410@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org From: Paul Moore [ Upstream commit 200ea5a2292dc444a818b096ae6a32ba3caa51b9 ] A previous fix, commit 83370b31a915 ("selinux: fix error initialization in inode_doinit_with_dentry()"), changed how failures were handled before a SELinux policy was loaded. Unfortunately that patch was potentially problematic for two reasons: it set the isec->initialized state without holding a lock, and it didn't set the inode's SELinux label to the "default" for the particular filesystem. The later can be a problem if/when a later attempt to revalidate the inode fails and SELinux reverts to the existing inode label. This patch should restore the default inode labeling that existed before the original fix, without affecting the LABEL_INVALID marking such that revalidation will still be attempted in the future. Fixes: 83370b31a915 ("selinux: fix error initialization in inode_doinit_with_dentry()") Reported-by: Sven Schnelle Tested-by: Sven Schnelle Reviewed-by: Ondrej Mosnacek Signed-off-by: Paul Moore Signed-off-by: Sasha Levin --- security/selinux/hooks.c | 31 +++++++++++++------------------ 1 file changed, 13 insertions(+), 18 deletions(-) diff --git a/security/selinux/hooks.c b/security/selinux/hooks.c index 02afe52a55d0d..08833bbb97aab 100644 --- a/security/selinux/hooks.c +++ b/security/selinux/hooks.c @@ -1618,13 +1618,7 @@ static int inode_doinit_with_dentry(struct inode *inode, struct dentry *opt_dent * inode_doinit with a dentry, before these inodes could * be used again by userspace. */ - isec->initialized = LABEL_INVALID; - /* - * There is nothing useful to jump to the "out" - * label, except a needless spin lock/unlock - * cycle. - */ - return 0; + goto out_invalid; } len = INITCONTEXTLEN; @@ -1739,15 +1733,8 @@ static int inode_doinit_with_dentry(struct inode *inode, struct dentry *opt_dent * inode_doinit() with a dentry, before these inodes * could be used again by userspace. */ - if (!dentry) { - isec->initialized = LABEL_INVALID; - /* - * There is nothing useful to jump to the "out" - * label, except a needless spin lock/unlock - * cycle. - */ - return 0; - } + if (!dentry) + goto out_invalid; rc = selinux_genfs_get_sid(dentry, sclass, sbsec->flags, &sid); dput(dentry); @@ -1760,11 +1747,10 @@ static int inode_doinit_with_dentry(struct inode *inode, struct dentry *opt_dent out: spin_lock(&isec->lock); if (isec->initialized == LABEL_PENDING) { - if (!sid || rc) { + if (rc) { isec->initialized = LABEL_INVALID; goto out_unlock; } - isec->initialized = LABEL_INITIALIZED; isec->sid = sid; } @@ -1772,6 +1758,15 @@ out: out_unlock: spin_unlock(&isec->lock); return rc; + +out_invalid: + spin_lock(&isec->lock); + if (isec->initialized == LABEL_PENDING) { + isec->initialized = LABEL_INVALID; + isec->sid = sid; + } + spin_unlock(&isec->lock); + return 0; } /* Convert a Linux signal to an access vector. */