From patchwork Tue Feb 11 16:57:42 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Christian Brauner X-Patchwork-Id: 11375965 Return-Path: Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 02F3D1580 for ; Tue, 11 Feb 2020 17:00:14 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id E01252086A for ; Tue, 11 Feb 2020 17:00:13 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1731000AbgBKQ7k (ORCPT ); Tue, 11 Feb 2020 11:59:40 -0500 Received: from youngberry.canonical.com ([91.189.89.112]:53461 "EHLO youngberry.canonical.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1730986AbgBKQ7k (ORCPT ); Tue, 11 Feb 2020 11:59:40 -0500 Received: from ip5f5bf7ec.dynamic.kabel-deutschland.de ([95.91.247.236] helo=wittgenstein.fritz.box) by youngberry.canonical.com with esmtpsa (TLS1.2:ECDHE_RSA_AES_128_GCM_SHA256:128) (Exim 4.86_2) (envelope-from ) id 1j1YsZ-00014T-03; Tue, 11 Feb 2020 16:59:19 +0000 From: Christian Brauner To: =?utf-8?q?St=C3=A9phane_Graber?= , "Eric W. Biederman" , Aleksa Sarai , Jann Horn Cc: smbarber@chromium.org, Alexander Viro , Alexey Dobriyan , Serge Hallyn , James Morris , Kees Cook , Jonathan Corbet , linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org, containers@lists.linux-foundation.org, linux-security-module@vger.kernel.org, linux-api@vger.kernel.org, Christian Brauner Subject: [PATCH 13/24] attr: notify_change(): handle fsid mappings Date: Tue, 11 Feb 2020 17:57:42 +0100 Message-Id: <20200211165753.356508-14-christian.brauner@ubuntu.com> X-Mailer: git-send-email 2.25.0 In-Reply-To: <20200211165753.356508-1-christian.brauner@ubuntu.com> References: <20200211165753.356508-1-christian.brauner@ubuntu.com> MIME-Version: 1.0 Sender: owner-linux-security-module@vger.kernel.org Precedence: bulk List-ID: Switch notify_change() to lookup fsids in the fsid mappings. If no fsid mappings are setup the behavior is unchanged, i.e. fsids are looked up in the id mappings. Filesystems that share a superblock in all user namespaces they are mounted in will retain their old semantics even with the introduction of fsidmappings. Signed-off-by: Christian Brauner --- fs/attr.c | 23 +++++++++++++++++------ 1 file changed, 17 insertions(+), 6 deletions(-) diff --git a/fs/attr.c b/fs/attr.c index df28035aa23e..3aa65165fb06 100644 --- a/fs/attr.c +++ b/fs/attr.c @@ -17,6 +17,8 @@ #include #include #include +#include +#include static bool chown_ok(const struct inode *inode, kuid_t uid) { @@ -311,12 +313,21 @@ int notify_change(struct dentry * dentry, struct iattr * attr, struct inode **de * Verify that uid/gid changes are valid in the target * namespace of the superblock. */ - if (ia_valid & ATTR_UID && - !kuid_has_mapping(inode->i_sb->s_user_ns, attr->ia_uid)) - return -EOVERFLOW; - if (ia_valid & ATTR_GID && - !kgid_has_mapping(inode->i_sb->s_user_ns, attr->ia_gid)) - return -EOVERFLOW; + if (is_userns_visible(inode->i_sb->s_iflags)) { + if (ia_valid & ATTR_UID && + !kuid_has_mapping(inode->i_sb->s_user_ns, attr->ia_uid)) + return -EOVERFLOW; + if (ia_valid & ATTR_GID && + !kgid_has_mapping(inode->i_sb->s_user_ns, attr->ia_gid)) + return -EOVERFLOW; + } else { + if (ia_valid & ATTR_UID && + !kfsuid_has_mapping(inode->i_sb->s_user_ns, attr->ia_uid)) + return -EOVERFLOW; + if (ia_valid & ATTR_GID && + !kfsgid_has_mapping(inode->i_sb->s_user_ns, attr->ia_gid)) + return -EOVERFLOW; + } /* Don't allow modifications of files with invalid uids or * gids unless those uids & gids are being made valid.