From patchwork Mon May 16 16:47:08 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Stefan Roesch X-Patchwork-Id: 12851161 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 8735AC4167E for ; Mon, 16 May 2022 16:48:47 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229670AbiEPQsq (ORCPT ); Mon, 16 May 2022 12:48:46 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:37396 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1343847AbiEPQsm (ORCPT ); Mon, 16 May 2022 12:48:42 -0400 Received: from mx0a-00082601.pphosted.com (mx0a-00082601.pphosted.com [67.231.145.42]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 3A0E23C73C for ; Mon, 16 May 2022 09:48:38 -0700 (PDT) Received: from pps.filterd (m0109334.ppops.net [127.0.0.1]) by mx0a-00082601.pphosted.com (8.17.1.5/8.17.1.5) with ESMTP id 24G9moC9023345 for ; Mon, 16 May 2022 09:48:38 -0700 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=fb.com; h=from : to : cc : subject : date : message-id : in-reply-to : references : mime-version : content-transfer-encoding : content-type; s=facebook; bh=ZB0I0bygTGrWfOs7D0mNHGqlVbLHHpR2apSClL45abY=; b=euqVurTK/gZEO85M875k+9xB1Qj3rwAcCydyzNZvix+svD/mTouDXWZeJ8dgDvHxGSFA k1vjJonSlB2OJ0Th4VvvtHdJaFx2STR55xu42cQtX+nOD4sE+VajDhFTQ1FEkKjLsu33 GlK4zG24OjuibZRUwb0vMlBOusEBeaAW2vk= Received: from mail.thefacebook.com ([163.114.132.120]) by mx0a-00082601.pphosted.com (PPS) with ESMTPS id 3g3maajdtd-5 (version=TLSv1.2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128 verify=NOT) for ; Mon, 16 May 2022 09:48:37 -0700 Received: from twshared6696.05.ash7.facebook.com (2620:10d:c085:108::4) by mail.thefacebook.com (2620:10d:c085:21d::5) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2375.24; Mon, 16 May 2022 09:48:37 -0700 Received: by devvm225.atn0.facebook.com (Postfix, from userid 425415) id 5E6E2F146DDB; Mon, 16 May 2022 09:48:25 -0700 (PDT) From: Stefan Roesch To: , , , , CC: , , Subject: [RFC PATCH v2 06/16] fs: split off need_remove_file_privs() do_remove_file_privs() Date: Mon, 16 May 2022 09:47:08 -0700 Message-ID: <20220516164718.2419891-7-shr@fb.com> X-Mailer: git-send-email 2.30.2 In-Reply-To: <20220516164718.2419891-1-shr@fb.com> References: <20220516164718.2419891-1-shr@fb.com> MIME-Version: 1.0 X-FB-Internal: Safe X-Proofpoint-ORIG-GUID: LIh7yJ_kSK6xeCO-RBz0cStaJZcy2iMB X-Proofpoint-GUID: LIh7yJ_kSK6xeCO-RBz0cStaJZcy2iMB X-Proofpoint-Virus-Version: vendor=baseguard engine=ICAP:2.0.205,Aquarius:18.0.858,Hydra:6.0.486,FMLib:17.11.64.514 definitions=2022-05-16_15,2022-05-16_02,2022-02-23_01 Precedence: bulk List-ID: X-Mailing-List: io-uring@vger.kernel.org This splits off the function need_remove_file_privs() from the function do_remove_file_privs() from the function file_remove_privs(). No intended functional changes in this patch. Signed-off-by: Stefan Roesch --- fs/inode.c | 57 ++++++++++++++++++++++++++++++++++++------------------ 1 file changed, 38 insertions(+), 19 deletions(-) diff --git a/fs/inode.c b/fs/inode.c index 9d9b422504d1..a6d70a1983f8 100644 --- a/fs/inode.c +++ b/fs/inode.c @@ -2010,17 +2010,8 @@ static int __remove_privs(struct user_namespace *mnt_userns, return notify_change(mnt_userns, dentry, &newattrs, NULL); } -/* - * Remove special file priviledges (suid, capabilities) when file is written - * to or truncated. - */ -int file_remove_privs(struct file *file) +static int need_file_remove_privs(struct inode *inode, struct dentry *dentry) { - struct dentry *dentry = file_dentry(file); - struct inode *inode = file_inode(file); - int kill; - int error = 0; - /* * Fast path for nothing security related. * As well for non-regular files, e.g. blkdev inodes. @@ -2030,16 +2021,37 @@ int file_remove_privs(struct file *file) if (IS_NOSEC(inode) || !S_ISREG(inode->i_mode)) return 0; - kill = dentry_needs_remove_privs(dentry); - if (kill < 0) - return kill; - if (kill) - error = __remove_privs(file_mnt_user_ns(file), dentry, kill); + return dentry_needs_remove_privs(dentry); +} + +static int do_file_remove_privs(struct file *file, struct inode *inode, + struct dentry *dentry, int kill) +{ + int error = 0; + + error = __remove_privs(file_mnt_user_ns(file), dentry, kill); if (!error) inode_has_no_xattr(inode); return error; } + +/* + * Remove special file privileges (suid, capabilities) when file is written + * to or truncated. + */ +int file_remove_privs(struct file *file) +{ + struct dentry *dentry = file_dentry(file); + struct inode *inode = file_inode(file); + int kill; + + kill = need_file_remove_privs(inode, dentry); + if (kill <= 0) + return kill; + + return do_file_remove_privs(file, inode, dentry, kill); +} EXPORT_SYMBOL(file_remove_privs); /** @@ -2093,15 +2105,22 @@ EXPORT_SYMBOL(file_update_time); /* Caller must hold the file's inode lock */ int file_modified(struct file *file) { - int err; + int ret; + struct dentry *dentry = file_dentry(file); + struct inode *inode = file_inode(file); /* * Clear the security bits if the process is not being run by root. * This keeps people from modifying setuid and setgid binaries. */ - err = file_remove_privs(file); - if (err) - return err; + ret = need_file_remove_privs(inode, dentry); + if (ret < 0) { + return ret; + } else if (ret > 0) { + ret = do_file_remove_privs(file, inode, dentry, ret); + if (ret) + return ret; + } if (unlikely(file->f_mode & FMODE_NOCMTIME)) return 0;