From mboxrd@z Thu Jan 1 00:00:00 1970 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 B2FCDC4332F for ; Tue, 30 Nov 2021 12:11:05 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S241433AbhK3MOW (ORCPT ); Tue, 30 Nov 2021 07:14:22 -0500 Received: from sin.source.kernel.org ([145.40.73.55]:36526 "EHLO sin.source.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S241430AbhK3MON (ORCPT ); Tue, 30 Nov 2021 07:14:13 -0500 Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by sin.source.kernel.org (Postfix) with ESMTPS id D9FCACE1870 for ; Tue, 30 Nov 2021 12:10:52 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 18A9EC53FCD; Tue, 30 Nov 2021 12:10:48 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1638274251; bh=MLiL8nGoAOq0haaFLjl21uP9MTvyXr/kKFDk7vn3T2c=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=j15tAED1KCkG6z4/kAvpYyErfxz9K1UGQsBKNfuglVOlqcHCoZLRq1Y/3fR/AL8aH PiCDeymVb7witPSsB7ICmsAhjfGl4V5NcitdFUALOE6FfnOHW3DRX75BXwTXoodoAh ++3+gGIEVnoxleJaD9tThdav/WxumRk3k5qfVW/S7f/pGOXAZDj4lHsLbeOMnDOsa+ kq1x4MkfoAu/WGSF8uEhYhOhsFA0g3Q4D8wict9lQ45ZqZjxL7tmtnMqmi4BhPl4w+ kxkTJFF3DpdKHa7l4QHBdg/uPeeK6GK7AnWWBL+aznRgN9cG8G3yvQKOxe10f83pjA uNz+pX9TLJKzA== From: Christian Brauner To: Christoph Hellwig Cc: Seth Forshee , Amir Goldstein , Al Viro , linux-fsdevel@vger.kernel.org, Christian Brauner Subject: [PATCH v2 01/10] fs: add is_idmapped_mnt() helper Date: Tue, 30 Nov 2021 13:10:23 +0100 Message-Id: <20211130121032.3753852-2-brauner@kernel.org> X-Mailer: git-send-email 2.30.2 In-Reply-To: <20211130121032.3753852-1-brauner@kernel.org> References: <20211130121032.3753852-1-brauner@kernel.org> MIME-Version: 1.0 X-Developer-Signature: v=1; a=openpgp-sha256; l=4760; h=from:subject; bh=Jhr19XJWOl5HFdB7VvVKH1dc2pE1uhAuVP1uatcCHdM=; b=owGbwMvMwCU28Zj0gdSKO4sYT6slMSQuE1nh/rTnkbu1/X/jEL5DP79sFXl2nfmD6+7crQ0nND+9 e/Qms6OUhUGMi0FWTJHFod0kXG45T8Vmo0wNmDmsTCBDGLg4BWAi57YxMmwtM966O/gv94Pq+DNcBd LrVpvs4zhsGOyRULfTOazX7CjD/xClJz3fM72PltWJ/3aUtrgcsX3RrKXJW0P3n1I6tqtVmQ8A X-Developer-Key: i=christian.brauner@ubuntu.com; a=openpgp; fpr=4880B8C9BD0E5106FC070F4F7B3C391EFEA93624 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-fsdevel@vger.kernel.org From: Christian Brauner Multiple places open-code the same check to determine whether a given mount is idmapped. Introduce a simple helper function that can be used instead. This allows us to get rid of the fragile open-coding. We will later change the check that is used to determine whether a given mount is idmapped. Introducing a helper allows us to do this in a single place instead of doing it for multiple places. Link: https://lore.kernel.org/r/20211123114227.3124056-2-brauner@kernel.org (v1) Cc: Seth Forshee Cc: Amir Goldstein Cc: Christoph Hellwig Cc: Al Viro CC: linux-fsdevel@vger.kernel.org Signed-off-by: Christian Brauner --- /* v2 */ - Amir Goldstein : - s/is_mapped_mnt/is_idmapped_mnt/g --- fs/cachefiles/bind.c | 2 +- fs/ecryptfs/main.c | 2 +- fs/namespace.c | 2 +- fs/nfsd/export.c | 2 +- fs/overlayfs/super.c | 2 +- fs/proc_namespace.c | 2 +- include/linux/fs.h | 14 ++++++++++++++ 7 files changed, 20 insertions(+), 6 deletions(-) diff --git a/fs/cachefiles/bind.c b/fs/cachefiles/bind.c index d463d89f5db8..146291be6263 100644 --- a/fs/cachefiles/bind.c +++ b/fs/cachefiles/bind.c @@ -117,7 +117,7 @@ static int cachefiles_daemon_add_cache(struct cachefiles_cache *cache) root = path.dentry; ret = -EINVAL; - if (mnt_user_ns(path.mnt) != &init_user_ns) { + if (is_idmapped_mnt(path.mnt)) { pr_warn("File cache on idmapped mounts not supported"); goto error_unsupported; } diff --git a/fs/ecryptfs/main.c b/fs/ecryptfs/main.c index d66bbd2df191..2dd23a82e0de 100644 --- a/fs/ecryptfs/main.c +++ b/fs/ecryptfs/main.c @@ -537,7 +537,7 @@ static struct dentry *ecryptfs_mount(struct file_system_type *fs_type, int flags goto out_free; } - if (mnt_user_ns(path.mnt) != &init_user_ns) { + if (is_idmapped_mnt(path.mnt)) { rc = -EINVAL; printk(KERN_ERR "Mounting on idmapped mounts currently disallowed\n"); goto out_free; diff --git a/fs/namespace.c b/fs/namespace.c index 659a8f39c61a..4994b816a74c 100644 --- a/fs/namespace.c +++ b/fs/namespace.c @@ -3936,7 +3936,7 @@ static int can_idmap_mount(const struct mount_kattr *kattr, struct mount *mnt) * mapping. It makes things simpler and callers can just create * another bind-mount they can idmap if they want to. */ - if (mnt_user_ns(m) != &init_user_ns) + if (is_idmapped_mnt(m)) return -EPERM; /* The underlying filesystem doesn't support idmapped mounts yet. */ diff --git a/fs/nfsd/export.c b/fs/nfsd/export.c index 9421dae22737..668c7527b17e 100644 --- a/fs/nfsd/export.c +++ b/fs/nfsd/export.c @@ -427,7 +427,7 @@ static int check_export(struct path *path, int *flags, unsigned char *uuid) return -EINVAL; } - if (mnt_user_ns(path->mnt) != &init_user_ns) { + if (is_idmapped_mnt(path->mnt)) { dprintk("exp_export: export of idmapped mounts not yet supported.\n"); return -EINVAL; } diff --git a/fs/overlayfs/super.c b/fs/overlayfs/super.c index 265181c110ae..7bb0a47cb615 100644 --- a/fs/overlayfs/super.c +++ b/fs/overlayfs/super.c @@ -873,7 +873,7 @@ static int ovl_mount_dir_noesc(const char *name, struct path *path) pr_err("filesystem on '%s' not supported\n", name); goto out_put; } - if (mnt_user_ns(path->mnt) != &init_user_ns) { + if (is_idmapped_mnt(path->mnt)) { pr_err("idmapped layers are currently not supported\n"); goto out_put; } diff --git a/fs/proc_namespace.c b/fs/proc_namespace.c index 392ef5162655..49650e54d2f8 100644 --- a/fs/proc_namespace.c +++ b/fs/proc_namespace.c @@ -80,7 +80,7 @@ static void show_mnt_opts(struct seq_file *m, struct vfsmount *mnt) seq_puts(m, fs_infop->str); } - if (mnt_user_ns(mnt) != &init_user_ns) + if (is_idmapped_mnt(mnt)) seq_puts(m, ",idmapped"); } diff --git a/include/linux/fs.h b/include/linux/fs.h index 1cb616fc1105..426cc7bcbeb8 100644 --- a/include/linux/fs.h +++ b/include/linux/fs.h @@ -2725,6 +2725,20 @@ static inline struct user_namespace *file_mnt_user_ns(struct file *file) { return mnt_user_ns(file->f_path.mnt); } + +/** + * is_idmapped_mnt - check whether a mount is mapped + * @mnt: the mount to check + * + * If @mnt has an idmapping attached to it @mnt is mapped. + * + * Return: true if mount is mapped, false if not. + */ +static inline bool is_idmapped_mnt(const struct vfsmount *mnt) +{ + return mnt_user_ns(mnt) != &init_user_ns; +} + extern long vfs_truncate(const struct path *, loff_t); int do_truncate(struct user_namespace *, struct dentry *, loff_t start, unsigned int time_attrs, struct file *filp); -- 2.30.2