From patchwork Tue Nov 23 11:42:18 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Christian Brauner X-Patchwork-Id: 12633979 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 6E754C433FE for ; Tue, 23 Nov 2021 11:42:55 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S236366AbhKWLqC (ORCPT ); Tue, 23 Nov 2021 06:46:02 -0500 Received: from mail.kernel.org ([198.145.29.99]:37340 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231150AbhKWLp5 (ORCPT ); Tue, 23 Nov 2021 06:45:57 -0500 Received: by mail.kernel.org (Postfix) with ESMTPSA id 17006604D1; Tue, 23 Nov 2021 11:42:47 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1637667769; bh=eDYWLoacrIiYU+DdVUwtlDVC1t/o0I9tt0WGcSZinJA=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=AggQMmn3srzih7d4BG4PUT69n4A5wdKlN/ltNksuX2nNk2MziKYXWfRyHEmpP2hxX JyOuYmJHU+xGOnH0A2a/7IVhhJNHYvOa9O9pyqF23SXX8VcxhF5zdVYP4ORLjzoed0 T1Y5e5jxCGSAFKi8WsvTV/TlVOrCgxOjgW5z2Qp5Wpiy9sopfQhDmciVSlcRPhlrM5 b5EfO0nIN/moOq+YkgCC/k9M+9299fW4JZiewRdaenp0n/y3whef63WPDnK0ShkevM ExFvGa3vvkpfMZXGw3j1eT9HTFBwJv1JjhizBaZmyrhI5zSiVp+d1HUBrnXkw1euhO jlOkob1rVpR2A== From: Christian Brauner To: Christoph Hellwig Cc: Seth Forshee , Al Viro , linux-fsdevel@vger.kernel.org, Christian Brauner Subject: [PATCH 01/10] fs: add is_mapped_mnt() helper Date: Tue, 23 Nov 2021 12:42:18 +0100 Message-Id: <20211123114227.3124056-2-brauner@kernel.org> X-Mailer: git-send-email 2.30.2 In-Reply-To: <20211123114227.3124056-1-brauner@kernel.org> References: <20211123114227.3124056-1-brauner@kernel.org> MIME-Version: 1.0 X-Developer-Signature: v=1; a=openpgp-sha256; l=4527; h=from:subject; bh=E6Fhc1ZBU9zBbB0af/1Zb4tZRcDPCL1SiNwHEUX+rVo=; b=owGbwMvMwCU28Zj0gdSKO4sYT6slMSTOuVx8QEho5tLtx/+bqOp2PZy9t6q922nXNqPOH9Fbkrgj kwzrOkpZGMS4GGTFFFkc2k3C5ZbzVGw2ytSAmcPKBDKEgYtTACaieJiR4fXP9REeDPWTL7/l1y6Zsn fKu8QbV0KPBr182sLLvfnUeTWG/0E/ox5k7vjGHCji+E5OmKdRdlH5sZYXTjs5PdPS7N9bMwMA X-Developer-Key: i=christian.brauner@ubuntu.com; a=openpgp; fpr=4880B8C9BD0E5106FC070F4F7B3C391EFEA93624 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. Cc: Seth Forshee Cc: Christoph Hellwig Cc: Al Viro CC: linux-fsdevel@vger.kernel.org Signed-off-by: Christian Brauner --- 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..8130142d89c2 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_mapped_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..331ac3a59515 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_mapped_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..7d7b80b375a4 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_mapped_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..292bde9e1eb3 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_mapped_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..113575fc6155 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_mapped_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..788c687bb052 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_mapped_mnt(mnt)) seq_puts(m, ",idmapped"); } diff --git a/include/linux/fs.h b/include/linux/fs.h index 1cb616fc1105..192242476b2b 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_mapped_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_mapped_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); From patchwork Tue Nov 23 11:42:19 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Christian Brauner X-Patchwork-Id: 12633985 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 DBACCC433EF for ; Tue, 23 Nov 2021 11:42:55 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S236399AbhKWLqC (ORCPT ); Tue, 23 Nov 2021 06:46:02 -0500 Received: from mail.kernel.org ([198.145.29.99]:37374 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S236363AbhKWLp7 (ORCPT ); Tue, 23 Nov 2021 06:45:59 -0500 Received: by mail.kernel.org (Postfix) with ESMTPSA id E3B1C6069B; Tue, 23 Nov 2021 11:42:49 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1637667771; bh=IpRRSSkZ/UrBlHGoEMSC6zqvaRukzygJG16S59esV8E=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=OkRgtLYGeOv43wR+Q5Gi6THRz31EIsMlxWeQ/jkuyFAWvhXMW47xkOqsBgS9Kaltj MhLtptpYFtS84sK/k5qEnyJojq376p4EXRzxcsyMnvbF5j7/GbDNqSs4uRPTnXV0PJ tjVYsWM3hrTCgEsZbFSRQUo1dvcH8XNNpGPSeLUhRZXSrj10LhYqlEePk/AudLHFoi FbUB7DhjAlQ/+lGtyoNeTRJFl+1sDUtbAfa961GYOBA+3UlJGoFs6NCQRSV4L2Dca8 zm1RD3lQemjSON+m5mx6qRiYbAHPn16y0TZlLIua05sXM/aG5bvGJ0a9n6EhRVLH9d Efhbkqje2jnVw== From: Christian Brauner To: Christoph Hellwig Cc: Seth Forshee , Al Viro , linux-fsdevel@vger.kernel.org, Christian Brauner Subject: [PATCH 02/10] fs: move mapping helpers Date: Tue, 23 Nov 2021 12:42:19 +0100 Message-Id: <20211123114227.3124056-3-brauner@kernel.org> X-Mailer: git-send-email 2.30.2 In-Reply-To: <20211123114227.3124056-1-brauner@kernel.org> References: <20211123114227.3124056-1-brauner@kernel.org> MIME-Version: 1.0 X-Developer-Signature: v=1; a=openpgp-sha256; l=8370; h=from:subject; bh=MCmibVNbOr2q/MjZn/cfH4ljQjMjIxE50K+YGoZjYj4=; b=owGbwMvMwCU28Zj0gdSKO4sYT6slMSTOuVys9rfhwQmJNrGatt3nNz1bc4njwoRvLpdijs5zutt9 VuzYhI5SFgYxLgZZMUUWh3aTcLnlPBWbjTI1YOawMoEMYeDiFICJJFUxMhz41nZvU3jgk9NT7C/NWc I/pf3y/0Vtq5/I6y3QV/c/cO06I8MjC9UX/fdy9s/5GtQX/vhIeWrWSu/0ZD1OoW+GHLqVYmwA X-Developer-Key: i=christian.brauner@ubuntu.com; a=openpgp; fpr=4880B8C9BD0E5106FC070F4F7B3C391EFEA93624 Precedence: bulk List-ID: X-Mailing-List: linux-fsdevel@vger.kernel.org From: Christian Brauner The low-level mapping helpers were so far crammed into fs.h. They are out of place there. The fs.h header should just contain the higher-level mapping helpers that interact directly with vfs objects such as struct super_block or struct inode and not the bare mapping helpers. Similarly, only vfs and specific fs code shall interact with low-level mapping helpers. And so they won't be made accessible automatically through regular {g,u}id helpers. Cc: Seth Forshee Cc: Christoph Hellwig Cc: Al Viro CC: linux-fsdevel@vger.kernel.org Signed-off-by: Christian Brauner --- include/linux/fs.h | 91 +------------------------------- include/linux/mnt_mapping.h | 101 ++++++++++++++++++++++++++++++++++++ 2 files changed, 102 insertions(+), 90 deletions(-) create mode 100644 include/linux/mnt_mapping.h diff --git a/include/linux/fs.h b/include/linux/fs.h index 192242476b2b..eb69e8b035fa 100644 --- a/include/linux/fs.h +++ b/include/linux/fs.h @@ -41,6 +41,7 @@ #include #include #include +#include #include #include @@ -1624,34 +1625,6 @@ static inline void i_gid_write(struct inode *inode, gid_t gid) inode->i_gid = make_kgid(inode->i_sb->s_user_ns, gid); } -/** - * kuid_into_mnt - map a kuid down into a mnt_userns - * @mnt_userns: user namespace of the relevant mount - * @kuid: kuid to be mapped - * - * Return: @kuid mapped according to @mnt_userns. - * If @kuid has no mapping INVALID_UID is returned. - */ -static inline kuid_t kuid_into_mnt(struct user_namespace *mnt_userns, - kuid_t kuid) -{ - return make_kuid(mnt_userns, __kuid_val(kuid)); -} - -/** - * kgid_into_mnt - map a kgid down into a mnt_userns - * @mnt_userns: user namespace of the relevant mount - * @kgid: kgid to be mapped - * - * Return: @kgid mapped according to @mnt_userns. - * If @kgid has no mapping INVALID_GID is returned. - */ -static inline kgid_t kgid_into_mnt(struct user_namespace *mnt_userns, - kgid_t kgid) -{ - return make_kgid(mnt_userns, __kgid_val(kgid)); -} - /** * i_uid_into_mnt - map an inode's i_uid down into a mnt_userns * @mnt_userns: user namespace of the mount the inode was found from @@ -1680,68 +1653,6 @@ static inline kgid_t i_gid_into_mnt(struct user_namespace *mnt_userns, return kgid_into_mnt(mnt_userns, inode->i_gid); } -/** - * kuid_from_mnt - map a kuid up into a mnt_userns - * @mnt_userns: user namespace of the relevant mount - * @kuid: kuid to be mapped - * - * Return: @kuid mapped up according to @mnt_userns. - * If @kuid has no mapping INVALID_UID is returned. - */ -static inline kuid_t kuid_from_mnt(struct user_namespace *mnt_userns, - kuid_t kuid) -{ - return KUIDT_INIT(from_kuid(mnt_userns, kuid)); -} - -/** - * kgid_from_mnt - map a kgid up into a mnt_userns - * @mnt_userns: user namespace of the relevant mount - * @kgid: kgid to be mapped - * - * Return: @kgid mapped up according to @mnt_userns. - * If @kgid has no mapping INVALID_GID is returned. - */ -static inline kgid_t kgid_from_mnt(struct user_namespace *mnt_userns, - kgid_t kgid) -{ - return KGIDT_INIT(from_kgid(mnt_userns, kgid)); -} - -/** - * mapped_fsuid - return caller's fsuid mapped up into a mnt_userns - * @mnt_userns: user namespace of the relevant mount - * - * Use this helper to initialize a new vfs or filesystem object based on - * the caller's fsuid. A common example is initializing the i_uid field of - * a newly allocated inode triggered by a creation event such as mkdir or - * O_CREAT. Other examples include the allocation of quotas for a specific - * user. - * - * Return: the caller's current fsuid mapped up according to @mnt_userns. - */ -static inline kuid_t mapped_fsuid(struct user_namespace *mnt_userns) -{ - return kuid_from_mnt(mnt_userns, current_fsuid()); -} - -/** - * mapped_fsgid - return caller's fsgid mapped up into a mnt_userns - * @mnt_userns: user namespace of the relevant mount - * - * Use this helper to initialize a new vfs or filesystem object based on - * the caller's fsgid. A common example is initializing the i_gid field of - * a newly allocated inode triggered by a creation event such as mkdir or - * O_CREAT. Other examples include the allocation of quotas for a specific - * user. - * - * Return: the caller's current fsgid mapped up according to @mnt_userns. - */ -static inline kgid_t mapped_fsgid(struct user_namespace *mnt_userns) -{ - return kgid_from_mnt(mnt_userns, current_fsgid()); -} - /** * inode_fsuid_set - initialize inode's i_uid field with callers fsuid * @inode: inode to initialize diff --git a/include/linux/mnt_mapping.h b/include/linux/mnt_mapping.h new file mode 100644 index 000000000000..7ff8b66b80cb --- /dev/null +++ b/include/linux/mnt_mapping.h @@ -0,0 +1,101 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +#ifndef _LINUX_MNT_MAPPING_H +#define _LINUX_MNT_MAPPING_H + +#include +#include + +struct user_namespace; +extern struct user_namespace init_user_ns; + +/** + * kuid_into_mnt - map a kuid down into a mnt_userns + * @mnt_userns: user namespace of the relevant mount + * @kuid: kuid to be mapped + * + * Return: @kuid mapped according to @mnt_userns. + * If @kuid has no mapping INVALID_UID is returned. + */ +static inline kuid_t kuid_into_mnt(struct user_namespace *mnt_userns, + kuid_t kuid) +{ + return make_kuid(mnt_userns, __kuid_val(kuid)); +} + +/** + * kgid_into_mnt - map a kgid down into a mnt_userns + * @mnt_userns: user namespace of the relevant mount + * @kgid: kgid to be mapped + * + * Return: @kgid mapped according to @mnt_userns. + * If @kgid has no mapping INVALID_GID is returned. + */ +static inline kgid_t kgid_into_mnt(struct user_namespace *mnt_userns, + kgid_t kgid) +{ + return make_kgid(mnt_userns, __kgid_val(kgid)); +} + +/** + * kuid_from_mnt - map a kuid up into a mnt_userns + * @mnt_userns: user namespace of the relevant mount + * @kuid: kuid to be mapped + * + * Return: @kuid mapped up according to @mnt_userns. + * If @kuid has no mapping INVALID_UID is returned. + */ +static inline kuid_t kuid_from_mnt(struct user_namespace *mnt_userns, + kuid_t kuid) +{ + return KUIDT_INIT(from_kuid(mnt_userns, kuid)); +} + +/** + * kgid_from_mnt - map a kgid up into a mnt_userns + * @mnt_userns: user namespace of the relevant mount + * @kgid: kgid to be mapped + * + * Return: @kgid mapped up according to @mnt_userns. + * If @kgid has no mapping INVALID_GID is returned. + */ +static inline kgid_t kgid_from_mnt(struct user_namespace *mnt_userns, + kgid_t kgid) +{ + return KGIDT_INIT(from_kgid(mnt_userns, kgid)); +} + +/** + * mapped_fsuid - return caller's fsuid mapped up into a mnt_userns + * @mnt_userns: user namespace of the relevant mount + * + * Use this helper to initialize a new vfs or filesystem object based on + * the caller's fsuid. A common example is initializing the i_uid field of + * a newly allocated inode triggered by a creation event such as mkdir or + * O_CREAT. Other examples include the allocation of quotas for a specific + * user. + * + * Return: the caller's current fsuid mapped up according to @mnt_userns. + */ +static inline kuid_t mapped_fsuid(struct user_namespace *mnt_userns) +{ + return kuid_from_mnt(mnt_userns, current_fsuid()); +} + +/** + * mapped_fsgid - return caller's fsgid mapped up into a mnt_userns + * @mnt_userns: user namespace of the relevant mount + * + * Use this helper to initialize a new vfs or filesystem object based on + * the caller's fsgid. A common example is initializing the i_gid field of + * a newly allocated inode triggered by a creation event such as mkdir or + * O_CREAT. Other examples include the allocation of quotas for a specific + * user. + * + * Return: the caller's current fsgid mapped up according to @mnt_userns. + */ +static inline kgid_t mapped_fsgid(struct user_namespace *mnt_userns) +{ + return kgid_from_mnt(mnt_userns, current_fsgid()); +} + +#endif /* _LINUX_MNT_MAPPING_H */ From patchwork Tue Nov 23 11:42:20 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Christian Brauner X-Patchwork-Id: 12633983 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 79F9DC43219 for ; Tue, 23 Nov 2021 11:42:56 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S236408AbhKWLqD (ORCPT ); Tue, 23 Nov 2021 06:46:03 -0500 Received: from mail.kernel.org ([198.145.29.99]:37396 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S236409AbhKWLqB (ORCPT ); Tue, 23 Nov 2021 06:46:01 -0500 Received: by mail.kernel.org (Postfix) with ESMTPSA id BD45561027; Tue, 23 Nov 2021 11:42:51 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1637667773; bh=3HVKuOoJpQQVgeGCOA77s6WuBmYiiIXMZ2nXvsHh1VM=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=OHl26BhWYlBb5JX+OL8HYxgzM/t5wxwB5IRf7vjkgY5w7sM3fQBXrxJvjAXCkZ9u4 G/N4kVwoleu/ldUZdSaoV7gyD4kHwYFJNggnw70ckqG+Df9wUx1pUNajGvNVRVU4y8 1SUaNG0B7eu4ZRwYKrBFmtPHbMHGO7xksaBkLMrwHnWcxvCR+YBy0EYl8ZnpV+Enao hTZBK+CIq/Y+4NmnsWz7c8HbLTbk1MebgQyhoWVw8wb9d14B4IydCs5juo2ChJcSDR KWHz9buhGHw6Ne++2Utr00QUCtez5PFlIoALoulWijXdqF3v4M8HB9Lx/Tasyfzvn0 VVGeNZ9U1iBcA== From: Christian Brauner To: Christoph Hellwig Cc: Seth Forshee , Al Viro , linux-fsdevel@vger.kernel.org, Christian Brauner Subject: [PATCH 03/10] fs: tweak fsuidgid_has_mapping() Date: Tue, 23 Nov 2021 12:42:20 +0100 Message-Id: <20211123114227.3124056-4-brauner@kernel.org> X-Mailer: git-send-email 2.30.2 In-Reply-To: <20211123114227.3124056-1-brauner@kernel.org> References: <20211123114227.3124056-1-brauner@kernel.org> MIME-Version: 1.0 X-Developer-Signature: v=1; a=openpgp-sha256; l=1615; h=from:subject; bh=BiM/wSu7WnhoUMqf8ScJVSixomvTuvNa162ansl70Wk=; b=owGbwMvMwCU28Zj0gdSKO4sYT6slMSTOuVxys+22a/XZWXNP2z/y1Foz6/Rm6ymFjr/505y/3rpq velcckcpC4MYF4OsmCKLQ7tJuNxynorNRpkaMHNYmUCGMHBxCsBE8v8w/LNns633MJ+pcfSGbkXjmd QlV33t/oSsbOYNqAhdl7CsVYKR4Z7W3W93Y+4IeDT3rV5e8/jNR/aza5NEDvz/mObXeIblJxsA X-Developer-Key: i=christian.brauner@ubuntu.com; a=openpgp; fpr=4880B8C9BD0E5106FC070F4F7B3C391EFEA93624 Precedence: bulk List-ID: X-Mailing-List: linux-fsdevel@vger.kernel.org From: Christian Brauner If the caller's fs{g,u}id aren't mapped in the mount's idmapping we can return early and skip the check whether the mapped fs{g,u}id also have a mapping in the filesystem's idmapping. If the fs{g,u}id aren't mapped in the mount's idmapping they consequently can't be mapped in the filesystem's idmapping. So there's no point in checking that. Cc: Seth Forshee Cc: Christoph Hellwig Cc: Al Viro CC: linux-fsdevel@vger.kernel.org Signed-off-by: Christian Brauner Reviewed-by: Amir Goldstein --- include/linux/fs.h | 14 +++++++++++--- 1 file changed, 11 insertions(+), 3 deletions(-) diff --git a/include/linux/fs.h b/include/linux/fs.h index eb69e8b035fa..161b5936094e 100644 --- a/include/linux/fs.h +++ b/include/linux/fs.h @@ -1695,10 +1695,18 @@ static inline void inode_fsgid_set(struct inode *inode, static inline bool fsuidgid_has_mapping(struct super_block *sb, struct user_namespace *mnt_userns) { - struct user_namespace *s_user_ns = sb->s_user_ns; + struct user_namespace *fs_userns = sb->s_user_ns; + kuid_t kuid; + kgid_t kgid; - return kuid_has_mapping(s_user_ns, mapped_fsuid(mnt_userns)) && - kgid_has_mapping(s_user_ns, mapped_fsgid(mnt_userns)); + kuid = mapped_fsuid(mnt_userns); + if (!uid_valid(kuid)) + return false; + kgid = mapped_fsgid(mnt_userns); + if (!gid_valid(kgid)) + return false; + return kuid_has_mapping(fs_userns, kuid) && + kgid_has_mapping(fs_userns, kgid); } extern struct timespec64 current_time(struct inode *inode); From patchwork Tue Nov 23 11:42:21 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Christian Brauner X-Patchwork-Id: 12633987 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 3C5CEC43217 for ; Tue, 23 Nov 2021 11:42:57 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S236409AbhKWLqE (ORCPT ); Tue, 23 Nov 2021 06:46:04 -0500 Received: from mail.kernel.org ([198.145.29.99]:37422 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S236398AbhKWLqC (ORCPT ); Tue, 23 Nov 2021 06:46:02 -0500 Received: by mail.kernel.org (Postfix) with ESMTPSA id 9701460240; Tue, 23 Nov 2021 11:42:53 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1637667774; bh=sjOl+eqJ4vXpUhZWPp+qRaGvx5y9g/4BNDijfMDBlEo=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=g1bltioVEbRUq+6yUYT/SLbj4IhCcsMZcKMJiPtxAs0f5arl0l473yx2FAOh17hXt d1OSWN1SxMrH+jbcBPlEt8gXT60bJ/Sc8I/2VaM6w5csHFMx3P0IhCRpS9Ha/eutFV ftknTDgGBpVTEMT1r8tAIkwGpS0Lrq9/ra6EaIHRTwojrVRr2z06pl8Cxt8/S8B+QA gxDrz6YdC7koRgv8h8ztzdGrXZiTuCZ9kG9klQUdrheh6bG6ZsOjnoWKcdArxHFVOd 5OIdY8d8gj3EvL4/eCSOflAqzWfW/Zl5HleZTTTjOG9vEu8Y5+/bYEapkbBXNv07jC zwzVpjpu64qMQ== From: Christian Brauner To: Christoph Hellwig Cc: Seth Forshee , Al Viro , linux-fsdevel@vger.kernel.org, Christian Brauner Subject: [PATCH 04/10] fs: account for filesystem mappings Date: Tue, 23 Nov 2021 12:42:21 +0100 Message-Id: <20211123114227.3124056-5-brauner@kernel.org> X-Mailer: git-send-email 2.30.2 In-Reply-To: <20211123114227.3124056-1-brauner@kernel.org> References: <20211123114227.3124056-1-brauner@kernel.org> MIME-Version: 1.0 X-Developer-Signature: v=1; a=openpgp-sha256; l=13328; h=from:subject; bh=2MyedI+91uaRUlJfcaMgnJQmt5YMF14tBbL299f9hRs=; b=owGbwMvMwCU28Zj0gdSKO4sYT6slMSTOuVwiovFqzbRZ7UEv2mwlHa1W5VhaPVI8zHzw+acrecmf zfV/dJSyMIhxMciKKbI4tJuEyy3nqdhslKkBM4eVCWQIAxenAExkRQfDP9ObZ3+1Xri8SJVdY1LNVq Wvap+k8t53XlI+y/DymEPWLWuG/67zXzKt8bHtKGj4ePn4+jsOu5fNKfm1fsqvI5yfuUo0jDgB X-Developer-Key: i=christian.brauner@ubuntu.com; a=openpgp; fpr=4880B8C9BD0E5106FC070F4F7B3C391EFEA93624 Precedence: bulk List-ID: X-Mailing-List: linux-fsdevel@vger.kernel.org From: Christian Brauner Currently we only support idmapped mounts for filesystems mounted without an idmapping. This was a conscious decision mentioned in multiple places (cf. e.g. [1]). As explained at length in [3] it is perfectly fine to extend support for idmapped mounts to filesystem's mounted with an idmapping should the need arise. The need has been there for some time now. Various container projects in userspace need this to run unprivileged and nested unprivileged containers (cf. [2]). Before we can port any filesystem that is mountable with an idmapping to support idmapped mounts we need to first extend the mapping helpers to account for the filesystem's idmapping. This again, is explained at length in our documentation at [3] but I'll give an overview here again. Currently, the low-level mapping helpers implement the remapping algorithms described in [3] in a simplified manner. Because we could rely on the fact that all filesystems supporting idmapped mounts are mounted without an idmapping the translation step from or into the filesystem idmapping could be skipped. In order to support idmapped mounts of filesystem's mountable with an idmapping the translation step we were able to skip before cannot be skipped anymore. A filesystem mounted with an idmapping is very likely to not use an identity mapping and will instead use a non-identity mapping. So the translation step from or into the filesystem's idmapping in the remapping algorithm cannot be skipped for such filesystems. More details with examples can be found in [3]. This patch adds a few new and prepares some already existing low-level mapping helpers to perform the full translation algorithm explained in [3]. The low-level helpers can be written in a way that they only perform the additional translation step when the filesystem is indeed mounted with an idmapping. If the low-level helpers detect that they are not dealing with an idmapped mount they can simply return the relevant k{g,u}id unchanged; no remapping needs to be performed at all. The no_mapping() helper detects whether the shortcut can be used. If the low-level helpers detected that they are dealing with an idmapped mount but the underlying filesystem is mounted without an idmapping we can rely on the previous shorcut and can continue to skip the translation step from or into the filesystem's idmapping. These checks guarantee that only the minimal amount of work is performed. As before, if idmapped mounts aren't used the low-level helpers are idempotent and no work is performed at all. This patch adds the helpers mapped_k{g,u}id_fs() and mapped_k{g,u}id_user(). Following patches will port all places to replace the old k{g,u}id_into_mnt() and k{g,u}id_from_mnt() with these two new helpers. After the conversion is done k{g,u}id_into_mnt() and k{g,u}id_from_mnt() will be removed. This also concludes the renaming of the mapping helpers we started in [4]. Now, all mapping helpers will started with the "mapped_" prefix making everything nice and consistent. The mapped_k{g,u}id_fs() helpers replace the k{g,u}id_into_mnt() helpers. They are to be used when k{g,u}ids are to be mapped from the vfs, e.g. from from struct inode's i_{g,u}id. Conversely, the mapped_k{g,u}id_user() helpers replace the k{g,u}id_from_mnt() helpers. They are to be used when k{g,u}ids are to be written to disk, e.g. when entering from a system call to change ownership of a file. This patch only introduces the helpers. It doesn't yet convert the relevant places to account for filesystem mounted with an idmapping. [1]: commit 2ca4dcc4909d ("fs/mount_setattr: tighten permission checks") [2]: https://github.com/containers/podman/issues/10374 [3]: Documentations/filesystems/idmappings.rst [4]: commit a65e58e791a1 ("fs: document and rename fsid helpers") Cc: Seth Forshee Cc: Christoph Hellwig Cc: Al Viro CC: linux-fsdevel@vger.kernel.org Signed-off-by: Christian Brauner --- include/linux/fs.h | 4 +- include/linux/mnt_mapping.h | 193 +++++++++++++++++++++++++++++++++++- 2 files changed, 191 insertions(+), 6 deletions(-) diff --git a/include/linux/fs.h b/include/linux/fs.h index 161b5936094e..b46fb111017b 100644 --- a/include/linux/fs.h +++ b/include/linux/fs.h @@ -1636,7 +1636,7 @@ static inline void i_gid_write(struct inode *inode, gid_t gid) static inline kuid_t i_uid_into_mnt(struct user_namespace *mnt_userns, const struct inode *inode) { - return kuid_into_mnt(mnt_userns, inode->i_uid); + return mapped_kuid_fs(mnt_userns, &init_user_ns, inode->i_uid); } /** @@ -1650,7 +1650,7 @@ static inline kuid_t i_uid_into_mnt(struct user_namespace *mnt_userns, static inline kgid_t i_gid_into_mnt(struct user_namespace *mnt_userns, const struct inode *inode) { - return kgid_into_mnt(mnt_userns, inode->i_gid); + return mapped_kgid_fs(mnt_userns, &init_user_ns, inode->i_gid); } /** diff --git a/include/linux/mnt_mapping.h b/include/linux/mnt_mapping.h index 7ff8b66b80cb..c555b9836d35 100644 --- a/include/linux/mnt_mapping.h +++ b/include/linux/mnt_mapping.h @@ -6,6 +6,11 @@ #include struct user_namespace; +/* + * Carries the initial idmapping of 0:0:4294967295 which is an identity + * mapping. This means that {g,u}id 0 is mapped to {g,u}id 0, {g,u}id 1 is + * mapped to {g,u}id 1, [...], {g,u}id 1000 to {g,u}id 1000, [...]. + */ extern struct user_namespace init_user_ns; /** @@ -64,9 +69,189 @@ static inline kgid_t kgid_from_mnt(struct user_namespace *mnt_userns, return KGIDT_INIT(from_kgid(mnt_userns, kgid)); } +/** + * initial_idmapping - check whether this is the initial mapping + * @ns: idmapping to check + * + * Check whether this is the initial mapping, mapping 0 to 0, 1 to 1, + * [...], 1000 to 1000 [...]. + * + * Return: true if this is the initial mapping, false if not. + */ +static inline bool initial_mapping(const struct user_namespace *ns) +{ + return ns == &init_user_ns; +} + +/** + * no_mapping - check whether we can skip remapping a kuid/gid + * @mnt_userns: the mount's idmapping + * @fs_userns: the filesystem's idmapping + * + * This function can be used to check whether a remapping between two + * idmappings is required. + * An idmapped mount is a mount that has an idmapping attached to it that + * is different from the filsystem's idmapping and the initial idmapping. + * If the initial mapping is used or the idmapping of the mount and the + * filesystem are identical no remapping is required. + * + * Return: true if remapping can be skipped, false if not. + */ +static inline bool no_mapping(const struct user_namespace *mnt_userns, + const struct user_namespace *fs_userns) +{ + return initial_mapping(mnt_userns) || mnt_userns == fs_userns; +} + +/** + * mapped_kuid_fs - map a filesystem kuid into a mnt_userns + * @mnt_userns: the mount's idmapping + * @fs_userns: the filesystem's idmapping + * @kuid : kuid to be mapped + * + * Take a @kuid and remap it from @fs_userns into @mnt_userns. Use this + * function when preparing a @kuid to be reported to userspace. + * + * If no_mapping() determines that this is not an idmapped mount we can + * simply return @kuid unchanged. + * If initial_mapping() tells us that the filesystem is not mounted with an + * idmapping we know the value of @kuid won't change when calling + * from_kuid() so we can simply retrieve the value via __kuid_val() + * directly. + * + * Return: @kuid mapped according to @mnt_userns. + * If @kuid has no mapping in either @mnt_userns or @fs_userns INVALID_UID is + * returned. + */ +static inline kuid_t mapped_kuid_fs(struct user_namespace *mnt_userns, + struct user_namespace *fs_userns, + kuid_t kuid) +{ + uid_t uid; + + if (no_mapping(mnt_userns, fs_userns)) + return kuid; + if (initial_mapping(fs_userns)) + uid = __kuid_val(kuid); + else + uid = from_kuid(fs_userns, kuid); + if (uid == (uid_t)-1) + return INVALID_UID; + return make_kuid(mnt_userns, uid); +} + +/** + * mapped_kgid_fs - map a filesystem kgid into a mnt_userns + * @mnt_userns: the mount's idmapping + * @fs_userns: the filesystem's idmapping + * @kgid : kgid to be mapped + * + * Take a @kgid and remap it from @fs_userns into @mnt_userns. Use this + * function when preparing a @kgid to be reported to userspace. + * + * If no_mapping() determines that this is not an idmapped mount we can + * simply return @kgid unchanged. + * If initial_mapping() tells us that the filesystem is not mounted with an + * idmapping we know the value of @kgid won't change when calling + * from_kgid() so we can simply retrieve the value via __kgid_val() + * directly. + * + * Return: @kgid mapped according to @mnt_userns. + * If @kgid has no mapping in either @mnt_userns or @fs_userns INVALID_GID is + * returned. + */ +static inline kgid_t mapped_kgid_fs(struct user_namespace *mnt_userns, + struct user_namespace *fs_userns, + kgid_t kgid) +{ + gid_t gid; + + if (no_mapping(mnt_userns, fs_userns)) + return kgid; + if (initial_mapping(fs_userns)) + gid = __kgid_val(kgid); + else + gid = from_kgid(fs_userns, kgid); + if (gid == (gid_t)-1) + return INVALID_GID; + return make_kgid(mnt_userns, gid); +} + +/** + * mapped_kuid_user - map a user kuid into a mnt_userns + * @mnt_userns: the mount's idmapping + * @fs_userns: the filesystem's idmapping + * @kuid : kuid to be mapped + * + * Use the idmapping of @mnt_userns to remap a @kuid into @fs_userns. Use this + * function when preparing a @kuid to be written to disk or inode. + * + * If no_mapping() determines that this is not an idmapped mount we can + * simply return @kuid unchanged. + * If initial_mapping() tells us that the filesystem is not mounted with an + * idmapping we know the value of @kuid won't change when calling + * make_kuid() so we can simply retrieve the value via KUIDT_INIT() + * directly. + * + * Return: @kuid mapped according to @mnt_userns. + * If @kuid has no mapping in either @mnt_userns or @fs_userns INVALID_UID is + * returned. + */ +static inline kuid_t mapped_kuid_user(struct user_namespace *mnt_userns, + struct user_namespace *fs_userns, + kuid_t kuid) +{ + uid_t uid; + + if (no_mapping(mnt_userns, fs_userns)) + return kuid; + uid = from_kuid(mnt_userns, kuid); + if (uid == (uid_t)-1) + return INVALID_UID; + if (initial_mapping(fs_userns)) + return KUIDT_INIT(uid); + return make_kuid(fs_userns, uid); +} + +/** + * mapped_kgid_user - map a user kgid into a mnt_userns + * @mnt_userns: the mount's idmapping + * @fs_userns: the filesystem's idmapping + * @kgid : kgid to be mapped + * + * Use the idmapping of @mnt_userns to remap a @kgid into @fs_userns. Use this + * function when preparing a @kgid to be written to disk or inode. + * + * If no_mapping() determines that this is not an idmapped mount we can + * simply return @kgid unchanged. + * If initial_mapping() tells us that the filesystem is not mounted with an + * idmapping we know the value of @kgid won't change when calling + * make_kgid() so we can simply retrieve the value via KGIDT_INIT() + * directly. + * + * Return: @kgid mapped according to @mnt_userns. + * If @kgid has no mapping in either @mnt_userns or @fs_userns INVALID_GID is + * returned. + */ +static inline kgid_t mapped_kgid_user(struct user_namespace *mnt_userns, + struct user_namespace *fs_userns, + kgid_t kgid) +{ + gid_t gid; + + if (no_mapping(mnt_userns, fs_userns)) + return kgid; + gid = from_kgid(mnt_userns, kgid); + if (gid == (gid_t)-1) + return INVALID_GID; + if (initial_mapping(fs_userns)) + return KGIDT_INIT(gid); + return make_kgid(fs_userns, gid); +} + /** * mapped_fsuid - return caller's fsuid mapped up into a mnt_userns - * @mnt_userns: user namespace of the relevant mount + * @mnt_userns: the mount's idmapping * * Use this helper to initialize a new vfs or filesystem object based on * the caller's fsuid. A common example is initializing the i_uid field of @@ -78,12 +263,12 @@ static inline kgid_t kgid_from_mnt(struct user_namespace *mnt_userns, */ static inline kuid_t mapped_fsuid(struct user_namespace *mnt_userns) { - return kuid_from_mnt(mnt_userns, current_fsuid()); + return mapped_kuid_user(mnt_userns, &init_user_ns, current_fsuid()); } /** * mapped_fsgid - return caller's fsgid mapped up into a mnt_userns - * @mnt_userns: user namespace of the relevant mount + * @mnt_userns: the mount's idmapping * * Use this helper to initialize a new vfs or filesystem object based on * the caller's fsgid. A common example is initializing the i_gid field of @@ -95,7 +280,7 @@ static inline kuid_t mapped_fsuid(struct user_namespace *mnt_userns) */ static inline kgid_t mapped_fsgid(struct user_namespace *mnt_userns) { - return kgid_from_mnt(mnt_userns, current_fsgid()); + return mapped_kgid_user(mnt_userns, &init_user_ns, current_fsgid()); } #endif /* _LINUX_MNT_MAPPING_H */ From patchwork Tue Nov 23 11:42:22 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Christian Brauner X-Patchwork-Id: 12633989 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 D86A7C433F5 for ; Tue, 23 Nov 2021 11:43:01 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S236425AbhKWLqI (ORCPT ); Tue, 23 Nov 2021 06:46:08 -0500 Received: from mail.kernel.org ([198.145.29.99]:37466 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S236422AbhKWLqE (ORCPT ); Tue, 23 Nov 2021 06:46:04 -0500 Received: by mail.kernel.org (Postfix) with ESMTPSA id 3EC936069B; Tue, 23 Nov 2021 11:42:55 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1637667776; bh=1UTjjQkNaYHI2FzQq25hRglMFeRNj7vYSe8g1jhfbM0=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=fq1BhDQKds4SckhIPiNxowbV3eT/F5dFBaDgowjTxSkQkLOt5Gt+zqvtKT7DXaDzv 8eHVGhaSSHX6k2KlpB6VhngLyBCLc41FfhnUrEuXaXKcQBj65O0rh85srqxhLobNP1 ZiRhYC/70vmnDO4MLwmBgBZFKHskKce7QTRpS5GHVhZs3xhwH9khWZxH2C2gJjkmjZ 4gZ9eoJ6/+z8C+dikEFvwzoPtE3LYd3YGz82pWjzp30TlwHXk344oi2AUTXD/8NOT2 92M+bY/JqwtxhzZZvgtTKCbhrxm/MDKqKI7SPS2rR6YLzQ39gTkskLEOlYJQd4ibjJ qZSb0pgICD7Xg== From: Christian Brauner To: Christoph Hellwig Cc: Seth Forshee , Al Viro , linux-fsdevel@vger.kernel.org, Christian Brauner Subject: [PATCH 05/10] docs: update mapping documentation Date: Tue, 23 Nov 2021 12:42:22 +0100 Message-Id: <20211123114227.3124056-6-brauner@kernel.org> X-Mailer: git-send-email 2.30.2 In-Reply-To: <20211123114227.3124056-1-brauner@kernel.org> References: <20211123114227.3124056-1-brauner@kernel.org> MIME-Version: 1.0 X-Developer-Signature: v=1; a=openpgp-sha256; l=4363; h=from:subject; bh=CetfUNWVqeKWRx77n5cjC8kVF3k66TOA5SiS1xK5kHM=; b=owGbwMvMwCU28Zj0gdSKO4sYT6slMSTOuVyyQHMSe1uXtfQlzrMiJ4Om2r2yrXuYL3VfdNPOvm9v vojwdpSyMIhxMciKKbI4tJuEyy3nqdhslKkBM4eVCWQIAxenAEzEdibD/7zpP8NuTfA7mnWcRWefkH 1VoXn5IoMD/Mf5/hrfOnXL/yYjw+Nz5VMPvYxW+K1eKcKTfGXtNLPY6zdnMLHE7RCO5Wh8zwQA X-Developer-Key: i=christian.brauner@ubuntu.com; a=openpgp; fpr=4880B8C9BD0E5106FC070F4F7B3C391EFEA93624 Precedence: bulk List-ID: X-Mailing-List: linux-fsdevel@vger.kernel.org From: Christian Brauner Now that we implement the full remapping algorithms described in our documentation remove the section about shortcircuting them. Cc: Seth Forshee Cc: Christoph Hellwig Cc: Al Viro CC: linux-fsdevel@vger.kernel.org Signed-off-by: Christian Brauner --- Documentation/filesystems/idmappings.rst | 72 ------------------------ 1 file changed, 72 deletions(-) diff --git a/Documentation/filesystems/idmappings.rst b/Documentation/filesystems/idmappings.rst index 1229a75ec75d..7a879ec3b6bf 100644 --- a/Documentation/filesystems/idmappings.rst +++ b/Documentation/filesystems/idmappings.rst @@ -952,75 +952,3 @@ The raw userspace id that is put on disk is ``u1000`` so when the user takes their home directory back to their home computer where they are assigned ``u1000`` using the initial idmapping and mount the filesystem with the initial idmapping they will see all those files owned by ``u1000``. - -Shortcircuting --------------- - -Currently, the implementation of idmapped mounts enforces that the filesystem -is mounted with the initial idmapping. The reason is simply that none of the -filesystems that we targeted were mountable with a non-initial idmapping. But -that might change soon enough. As we've seen above, thanks to the properties of -idmappings the translation works for both filesystems mounted with the initial -idmapping and filesystem with non-initial idmappings. - -Based on this current restriction to filesystem mounted with the initial -idmapping two noticeable shortcuts have been taken: - -1. We always stash a reference to the initial user namespace in ``struct - vfsmount``. Idmapped mounts are thus mounts that have a non-initial user - namespace attached to them. - - In order to support idmapped mounts this needs to be changed. Instead of - stashing the initial user namespace the user namespace the filesystem was - mounted with must be stashed. An idmapped mount is then any mount that has - a different user namespace attached then the filesystem was mounted with. - This has no user-visible consequences. - -2. The translation algorithms in ``mapped_fs*id()`` and ``i_*id_into_mnt()`` - are simplified. - - Let's consider ``mapped_fs*id()`` first. This function translates the - caller's kernel id into a kernel id in the filesystem's idmapping via - a mount's idmapping. The full algorithm is:: - - mapped_fsuid(kid): - /* Map the kernel id up into a userspace id in the mount's idmapping. */ - from_kuid(mount-idmapping, kid) = uid - - /* Map the userspace id down into a kernel id in the filesystem's idmapping. */ - make_kuid(filesystem-idmapping, uid) = kuid - - We know that the filesystem is always mounted with the initial idmapping as - we enforce this in ``mount_setattr()``. So this can be shortened to:: - - mapped_fsuid(kid): - /* Map the kernel id up into a userspace id in the mount's idmapping. */ - from_kuid(mount-idmapping, kid) = uid - - /* Map the userspace id down into a kernel id in the filesystem's idmapping. */ - KUIDT_INIT(uid) = kuid - - Similarly, for ``i_*id_into_mnt()`` which translated the filesystem's kernel - id into a mount's kernel id:: - - i_uid_into_mnt(kid): - /* Map the kernel id up into a userspace id in the filesystem's idmapping. */ - from_kuid(filesystem-idmapping, kid) = uid - - /* Map the userspace id down into a kernel id in the mounts's idmapping. */ - make_kuid(mount-idmapping, uid) = kuid - - Again, we know that the filesystem is always mounted with the initial - idmapping as we enforce this in ``mount_setattr()``. So this can be - shortened to:: - - i_uid_into_mnt(kid): - /* Map the kernel id up into a userspace id in the filesystem's idmapping. */ - __kuid_val(kid) = uid - - /* Map the userspace id down into a kernel id in the mounts's idmapping. */ - make_kuid(mount-idmapping, uid) = kuid - -Handling filesystems mounted with non-initial idmappings requires that the -translation functions be converted to their full form. They can still be -shortcircuited on non-idmapped mounts. This has no user-visible consequences. From patchwork Tue Nov 23 11:42:23 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Christian Brauner X-Patchwork-Id: 12633991 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 75810C433EF for ; Tue, 23 Nov 2021 11:43:02 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S236446AbhKWLqJ (ORCPT ); Tue, 23 Nov 2021 06:46:09 -0500 Received: from mail.kernel.org ([198.145.29.99]:37496 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S236427AbhKWLqG (ORCPT ); Tue, 23 Nov 2021 06:46:06 -0500 Received: by mail.kernel.org (Postfix) with ESMTPSA id F40A860E05; Tue, 23 Nov 2021 11:42:56 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1637667778; bh=/rTjeTPWBvcLK8wr+cO1MZN2iy1dh3v+tLbcaaytnu8=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=rIzIg8nIW12AWqzxNA/jub8lHMyk5SI8VB9oEF2Tuppu2SAm8LM3hjtZekhYT7y3U nzhM9V1cEALr+2G4hyPi2tY3Nk0evg3w9vZOvt/P/Ke5i2JsgygK8BdESLs68yGlhV CKehiUJoOCxCuLIeDjfR+4bP97Rh3+uhTrLWJZG9m+I0s6RbtvnzSt2wux6/c7TOMT zJAc8EJrd33mj3tI9JfDYjnrCmYmYmyS1EGG3z9NGu35OrOURi0iPvyJ7NWHsq5QNX x1i8GBi/b8d6SrFpK1S9PctzvIfegmyWHU9BhrzR9huphLBAzsuMh+lrGrb0ip7yKN VecJG175gPAeg== From: Christian Brauner To: Christoph Hellwig Cc: Seth Forshee , Al Viro , linux-fsdevel@vger.kernel.org, Christian Brauner Subject: [PATCH 06/10] fs: use low-level mapping helpers Date: Tue, 23 Nov 2021 12:42:23 +0100 Message-Id: <20211123114227.3124056-7-brauner@kernel.org> X-Mailer: git-send-email 2.30.2 In-Reply-To: <20211123114227.3124056-1-brauner@kernel.org> References: <20211123114227.3124056-1-brauner@kernel.org> MIME-Version: 1.0 X-Developer-Signature: v=1; a=openpgp-sha256; l=7819; h=from:subject; bh=xvtF5aZHVHe4SS8zPrO55/0FHCocop3aQUOcbCD9wr4=; b=owGbwMvMwCU28Zj0gdSKO4sYT6slMSTOuVwquics4Vvm9nNavC8K6/3DmUuWzZ3mPU3yeoTus+73 skuzOkpZGMS4GGTFFFkc2k3C5ZbzVGw2ytSAmcPKBDKEgYtTACay+S4jw4N6oynbLxVkPL/jGrF45t zDIatuTPN4o9+2nm22X+m6VyGMDBume2R0SeucYnLkjnNaFTcvsKFCxelDcPNvvmdqv4ufMwIA X-Developer-Key: i=christian.brauner@ubuntu.com; a=openpgp; fpr=4880B8C9BD0E5106FC070F4F7B3C391EFEA93624 Precedence: bulk List-ID: X-Mailing-List: linux-fsdevel@vger.kernel.org From: Christian Brauner In a few places the vfs needs to interact with bare k{g,u}ids directly instead of struct inode. These are just a few. In previous patches we introduced low-level mapping helpers that are able to support filesystems mounted an idmapping. This patch simply converts the places to use these new helpers. Cc: Seth Forshee Cc: Christoph Hellwig Cc: Al Viro CC: linux-fsdevel@vger.kernel.org Signed-off-by: Christian Brauner --- fs/ksmbd/smbacl.c | 18 ++---------------- fs/ksmbd/smbacl.h | 4 ++-- fs/open.c | 4 ++-- fs/posix_acl.c | 16 ++++++++++------ security/commoncap.c | 13 ++++++++----- 5 files changed, 24 insertions(+), 31 deletions(-) diff --git a/fs/ksmbd/smbacl.c b/fs/ksmbd/smbacl.c index bd792db32623..abd5e60a26bb 100644 --- a/fs/ksmbd/smbacl.c +++ b/fs/ksmbd/smbacl.c @@ -274,14 +274,7 @@ static int sid_to_id(struct user_namespace *user_ns, uid_t id; id = le32_to_cpu(psid->sub_auth[psid->num_subauth - 1]); - /* - * Translate raw sid into kuid in the server's user - * namespace. - */ - uid = make_kuid(&init_user_ns, id); - - /* If this is an idmapped mount, apply the idmapping. */ - uid = kuid_from_mnt(user_ns, uid); + uid = mapped_kuid_user(user_ns, &init_user_ns, KUIDT_INIT(id)); if (uid_valid(uid)) { fattr->cf_uid = uid; rc = 0; @@ -291,14 +284,7 @@ static int sid_to_id(struct user_namespace *user_ns, gid_t id; id = le32_to_cpu(psid->sub_auth[psid->num_subauth - 1]); - /* - * Translate raw sid into kgid in the server's user - * namespace. - */ - gid = make_kgid(&init_user_ns, id); - - /* If this is an idmapped mount, apply the idmapping. */ - gid = kgid_from_mnt(user_ns, gid); + gid = mapped_kgid_user(user_ns, &init_user_ns, KGIDT_INIT(id)); if (gid_valid(gid)) { fattr->cf_gid = gid; rc = 0; diff --git a/fs/ksmbd/smbacl.h b/fs/ksmbd/smbacl.h index 73e08cad412b..49030b22a545 100644 --- a/fs/ksmbd/smbacl.h +++ b/fs/ksmbd/smbacl.h @@ -216,7 +216,7 @@ static inline uid_t posix_acl_uid_translate(struct user_namespace *mnt_userns, kuid_t kuid; /* If this is an idmapped mount, apply the idmapping. */ - kuid = kuid_into_mnt(mnt_userns, pace->e_uid); + kuid = mapped_kuid_fs(mnt_userns, &init_user_ns, pace->e_uid); /* Translate the kuid into a userspace id ksmbd would see. */ return from_kuid(&init_user_ns, kuid); @@ -228,7 +228,7 @@ static inline gid_t posix_acl_gid_translate(struct user_namespace *mnt_userns, kgid_t kgid; /* If this is an idmapped mount, apply the idmapping. */ - kgid = kgid_into_mnt(mnt_userns, pace->e_gid); + kgid = mapped_kgid_fs(mnt_userns, &init_user_ns, pace->e_gid); /* Translate the kgid into a userspace id ksmbd would see. */ return from_kgid(&init_user_ns, kgid); diff --git a/fs/open.c b/fs/open.c index f732fb94600c..64f799d96356 100644 --- a/fs/open.c +++ b/fs/open.c @@ -652,8 +652,8 @@ int chown_common(const struct path *path, uid_t user, gid_t group) gid = make_kgid(current_user_ns(), group); mnt_userns = mnt_user_ns(path->mnt); - uid = kuid_from_mnt(mnt_userns, uid); - gid = kgid_from_mnt(mnt_userns, gid); + uid = mapped_kuid_user(mnt_userns, &init_user_ns, uid); + gid = mapped_kgid_user(mnt_userns, &init_user_ns, gid); retry_deleg: newattrs.ia_valid = ATTR_CTIME; diff --git a/fs/posix_acl.c b/fs/posix_acl.c index 9323a854a60a..e45b3ffb6de1 100644 --- a/fs/posix_acl.c +++ b/fs/posix_acl.c @@ -374,7 +374,9 @@ posix_acl_permission(struct user_namespace *mnt_userns, struct inode *inode, goto check_perm; break; case ACL_USER: - uid = kuid_into_mnt(mnt_userns, pa->e_uid); + uid = mapped_kuid_fs(mnt_userns, + &init_user_ns, + pa->e_uid); if (uid_eq(uid, current_fsuid())) goto mask; break; @@ -387,7 +389,9 @@ posix_acl_permission(struct user_namespace *mnt_userns, struct inode *inode, } break; case ACL_GROUP: - gid = kgid_into_mnt(mnt_userns, pa->e_gid); + gid = mapped_kgid_fs(mnt_userns, + &init_user_ns, + pa->e_gid); if (in_group_p(gid)) { found = 1; if ((pa->e_perm & want) == want) @@ -734,17 +738,17 @@ static void posix_acl_fix_xattr_userns( case ACL_USER: uid = make_kuid(from, le32_to_cpu(entry->e_id)); if (from_user) - uid = kuid_from_mnt(mnt_userns, uid); + uid = mapped_kuid_user(mnt_userns, &init_user_ns, uid); else - uid = kuid_into_mnt(mnt_userns, uid); + uid = mapped_kuid_fs(mnt_userns, &init_user_ns, uid); entry->e_id = cpu_to_le32(from_kuid(to, uid)); break; case ACL_GROUP: gid = make_kgid(from, le32_to_cpu(entry->e_id)); if (from_user) - gid = kgid_from_mnt(mnt_userns, gid); + gid = mapped_kgid_user(mnt_userns, &init_user_ns, gid); else - gid = kgid_into_mnt(mnt_userns, gid); + gid = mapped_kgid_fs(mnt_userns, &init_user_ns, gid); entry->e_id = cpu_to_le32(from_kgid(to, gid)); break; default: diff --git a/security/commoncap.c b/security/commoncap.c index 3f810d37b71b..77d319f62710 100644 --- a/security/commoncap.c +++ b/security/commoncap.c @@ -418,7 +418,7 @@ int cap_inode_getsecurity(struct user_namespace *mnt_userns, kroot = make_kuid(fs_ns, root); /* If this is an idmapped mount shift the kuid. */ - kroot = kuid_into_mnt(mnt_userns, kroot); + kroot = mapped_kuid_fs(mnt_userns, &init_user_ns, kroot); /* If the root kuid maps to a valid uid in current ns, then return * this as a nscap. */ @@ -488,6 +488,7 @@ int cap_inode_getsecurity(struct user_namespace *mnt_userns, * @size: size of @ivalue * @task_ns: user namespace of the caller * @mnt_userns: user namespace of the mount the inode was found from + * @fs_userns: user namespace of the filesystem * * If the inode has been found through an idmapped mount the user namespace of * the vfsmount must be passed through @mnt_userns. This function will then @@ -497,7 +498,8 @@ int cap_inode_getsecurity(struct user_namespace *mnt_userns, */ static kuid_t rootid_from_xattr(const void *value, size_t size, struct user_namespace *task_ns, - struct user_namespace *mnt_userns) + struct user_namespace *mnt_userns, + struct user_namespace *fs_userns) { const struct vfs_ns_cap_data *nscap = value; kuid_t rootkid; @@ -507,7 +509,7 @@ static kuid_t rootid_from_xattr(const void *value, size_t size, rootid = le32_to_cpu(nscap->rootid); rootkid = make_kuid(task_ns, rootid); - return kuid_from_mnt(mnt_userns, rootkid); + return mapped_kuid_user(mnt_userns, fs_userns, rootkid); } static bool validheader(size_t size, const struct vfs_cap_data *cap) @@ -558,7 +560,8 @@ int cap_convert_nscap(struct user_namespace *mnt_userns, struct dentry *dentry, /* user is privileged, just write the v2 */ return size; - rootid = rootid_from_xattr(*ivalue, size, task_ns, mnt_userns); + rootid = rootid_from_xattr(*ivalue, size, task_ns, mnt_userns, + &init_user_ns); if (!uid_valid(rootid)) return -EINVAL; @@ -699,7 +702,7 @@ int get_vfs_caps_from_disk(struct user_namespace *mnt_userns, /* Limit the caps to the mounter of the filesystem * or the more limited uid specified in the xattr. */ - rootkuid = kuid_into_mnt(mnt_userns, rootkuid); + rootkuid = mapped_kuid_fs(mnt_userns, &init_user_ns, rootkuid); if (!rootid_owns_currentns(rootkuid)) return -ENODATA; From patchwork Tue Nov 23 11:42:24 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Christian Brauner X-Patchwork-Id: 12633993 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 B0B0DC433FE for ; Tue, 23 Nov 2021 11:43:03 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S236444AbhKWLqJ (ORCPT ); Tue, 23 Nov 2021 06:46:09 -0500 Received: from mail.kernel.org ([198.145.29.99]:37532 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S236419AbhKWLqI (ORCPT ); Tue, 23 Nov 2021 06:46:08 -0500 Received: by mail.kernel.org (Postfix) with ESMTPSA id CD63961028; Tue, 23 Nov 2021 11:42:58 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1637667780; bh=M+JaEg2RT5fj5F0W4xzGQDdowgzdRhhOGLcBClbcOx0=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=em50dK6tYhdFvTDXLWywAOQWcU57vnwHDL0Az54tUB3ycI13ckzi9S0/zygYlnyN9 ku5qleR3eN/s7+TWJZ4uhZKi3vS5jiNAaJGU8TMubJ5sumIoe2hryTP7o/gQyeaUBM Mat0WESd0rJtk5ga7natkZT0oCgoyd3odIDx+klXJbNh+obOxpuyv28xRRQET+RK7z dFUbIonjrEsPatDkk+dXY/QmzxO1nVOlOB8bB1sh7GKpCO03GuyMRMittWNJccRTin 2uAkS/nmRsNDmUqnizkVga/ojMTd48HdrrWgWtMgVbpYmYes463hYx8Qs7vd9O6pYF nxIV/FHwgTGUw== From: Christian Brauner To: Christoph Hellwig Cc: Seth Forshee , Al Viro , linux-fsdevel@vger.kernel.org, Christian Brauner Subject: [PATCH 07/10] fs: remove unused low-level mapping helpers Date: Tue, 23 Nov 2021 12:42:24 +0100 Message-Id: <20211123114227.3124056-8-brauner@kernel.org> X-Mailer: git-send-email 2.30.2 In-Reply-To: <20211123114227.3124056-1-brauner@kernel.org> References: <20211123114227.3124056-1-brauner@kernel.org> MIME-Version: 1.0 X-Developer-Signature: v=1; a=openpgp-sha256; l=2775; h=from:subject; bh=sQNQwAKITQlBki0kjx3b4Jwr64/5Px+y6rVmxx3vUXY=; b=owGbwMvMwCU28Zj0gdSKO4sYT6slMSTOuVy6Oq99q6TI45O3/+27VPv7+b9/1/ke8bOcK1i5UsPf w0NtSkcpC4MYF4OsmCKLQ7tJuNxynorNRpkaMHNYmUCGMHBxCsBEuKUZGY7M1/jbqmilxMNqr3Lwxz 9Bg40hK35qv8o3SVrSbjJjnzgjw1P7jDZ9Rf9n4vv3/1a4yNty9roSn+/if0GJt7LmhR1XYwMA X-Developer-Key: i=christian.brauner@ubuntu.com; a=openpgp; fpr=4880B8C9BD0E5106FC070F4F7B3C391EFEA93624 Precedence: bulk List-ID: X-Mailing-List: linux-fsdevel@vger.kernel.org From: Christian Brauner Now that we ported all places to use the new low-level mapping helpers that are able to support filesystems mounted with an idmapping we can remove the old low-level mapping helpers. With the removal of these old helpers we also conclude the renaming of the mapping helpers we started in [1]. [1]: commit a65e58e791a1 ("fs: document and rename fsid helpers") Cc: Seth Forshee Cc: Christoph Hellwig Cc: Al Viro CC: linux-fsdevel@vger.kernel.org Signed-off-by: Christian Brauner Reviewed-by: Amir Goldstein --- include/linux/mnt_mapping.h | 56 ------------------------------------- 1 file changed, 56 deletions(-) diff --git a/include/linux/mnt_mapping.h b/include/linux/mnt_mapping.h index c555b9836d35..f55b62fd27ae 100644 --- a/include/linux/mnt_mapping.h +++ b/include/linux/mnt_mapping.h @@ -13,62 +13,6 @@ struct user_namespace; */ extern struct user_namespace init_user_ns; -/** - * kuid_into_mnt - map a kuid down into a mnt_userns - * @mnt_userns: user namespace of the relevant mount - * @kuid: kuid to be mapped - * - * Return: @kuid mapped according to @mnt_userns. - * If @kuid has no mapping INVALID_UID is returned. - */ -static inline kuid_t kuid_into_mnt(struct user_namespace *mnt_userns, - kuid_t kuid) -{ - return make_kuid(mnt_userns, __kuid_val(kuid)); -} - -/** - * kgid_into_mnt - map a kgid down into a mnt_userns - * @mnt_userns: user namespace of the relevant mount - * @kgid: kgid to be mapped - * - * Return: @kgid mapped according to @mnt_userns. - * If @kgid has no mapping INVALID_GID is returned. - */ -static inline kgid_t kgid_into_mnt(struct user_namespace *mnt_userns, - kgid_t kgid) -{ - return make_kgid(mnt_userns, __kgid_val(kgid)); -} - -/** - * kuid_from_mnt - map a kuid up into a mnt_userns - * @mnt_userns: user namespace of the relevant mount - * @kuid: kuid to be mapped - * - * Return: @kuid mapped up according to @mnt_userns. - * If @kuid has no mapping INVALID_UID is returned. - */ -static inline kuid_t kuid_from_mnt(struct user_namespace *mnt_userns, - kuid_t kuid) -{ - return KUIDT_INIT(from_kuid(mnt_userns, kuid)); -} - -/** - * kgid_from_mnt - map a kgid up into a mnt_userns - * @mnt_userns: user namespace of the relevant mount - * @kgid: kgid to be mapped - * - * Return: @kgid mapped up according to @mnt_userns. - * If @kgid has no mapping INVALID_GID is returned. - */ -static inline kgid_t kgid_from_mnt(struct user_namespace *mnt_userns, - kgid_t kgid) -{ - return KGIDT_INIT(from_kgid(mnt_userns, kgid)); -} - /** * initial_idmapping - check whether this is the initial mapping * @ns: idmapping to check From patchwork Tue Nov 23 11:42:25 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Christian Brauner X-Patchwork-Id: 12633997 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 27AD9C433F5 for ; Tue, 23 Nov 2021 11:43:07 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S236427AbhKWLqO (ORCPT ); Tue, 23 Nov 2021 06:46:14 -0500 Received: from mail.kernel.org ([198.145.29.99]:37568 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S236441AbhKWLqK (ORCPT ); Tue, 23 Nov 2021 06:46:10 -0500 Received: by mail.kernel.org (Postfix) with ESMTPSA id A0AF660240; Tue, 23 Nov 2021 11:43:00 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1637667782; bh=aHTObxp2QlNutltSti2v81inpBtEPMRjC/7G/erOuls=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=T33sY07lkcxLui6SPt53uCuXblLmcfwrZRHt7Wuq5TPxm1DNyDr0pJLR4p+nIA6IF ZXZySkjWjn7wt0/Y38aGD42JXUVuagqE+7IufeCU7JOkd9ckE2UODkVJM8pBSsece0 Tmttry71VXh1dp4XJkz7QPyr/870scXUbTmJ+EjLyMj5nF5scRcUqmV2oUF+oyiNdN frUGGFhW7N9VNkC3qAzFcEfMVgb1blI0TkOFTJ/AXYOr/Zrt9wXgA8Mtv+wtsSvHww WwS5U4rCxKF8jPMSlUhhJX8o+rky86FAMnUSD6x9bKv9yucH8OjHzqTfQ7j8WOcTDC Yhq/rCG3rNYlw== From: Christian Brauner To: Christoph Hellwig Cc: Seth Forshee , Al Viro , linux-fsdevel@vger.kernel.org, Christian Brauner Subject: [PATCH 08/10] fs: port higher-level mapping helpers Date: Tue, 23 Nov 2021 12:42:25 +0100 Message-Id: <20211123114227.3124056-9-brauner@kernel.org> X-Mailer: git-send-email 2.30.2 In-Reply-To: <20211123114227.3124056-1-brauner@kernel.org> References: <20211123114227.3124056-1-brauner@kernel.org> MIME-Version: 1.0 X-Developer-Signature: v=1; a=openpgp-sha256; l=6250; h=from:subject; bh=xqFNMn31fegqh0TT9/RZQrtDaVPF2JVrt+Jsn8Qob4w=; b=owGbwMvMwCU28Zj0gdSKO4sYT6slMSTOuVxqduy2uF1X9ZaHayd0bciyuqnjfPr/h1vrry07G+vp fDUuo6OUhUGMi0FWTJHFod0kXG45T8Vmo0wNmDmsTCBDGLg4BWAigksZ/vCb7LovkMH3NPzczaV2/2 YcbSuM2LfBc4d5dVbhwcUcs6QZ/oqZnM+0OlhhwLbG7bZ+WY7d6Q4pmZI2KzbZM9LP9/zs4gEA X-Developer-Key: i=christian.brauner@ubuntu.com; a=openpgp; fpr=4880B8C9BD0E5106FC070F4F7B3C391EFEA93624 Precedence: bulk List-ID: X-Mailing-List: linux-fsdevel@vger.kernel.org From: Christian Brauner Enable the mapped_fs{g,u}id() helpers to support filesystems mounted with an idmapping. Apart from core mapping helpers that use mapped_fs{g,u}id() to initialize struct inode's i_{g,u}id fields xfs is the only place that uses these low-level helpers directly. The patch only extends the helpers to be able to take the filesystem idmapping into account. Since we don't actually yet pass the filesystem's idmapping in no functional changes happen. This will happen in a final patch. Cc: Seth Forshee Cc: Christoph Hellwig Cc: Al Viro CC: linux-fsdevel@vger.kernel.org Signed-off-by: Christian Brauner Reviewed-by: Amir Goldstein --- fs/xfs/xfs_inode.c | 10 ++++++---- fs/xfs/xfs_symlink.c | 5 +++-- include/linux/fs.h | 8 ++++---- include/linux/mnt_mapping.h | 12 ++++++++---- 4 files changed, 21 insertions(+), 14 deletions(-) diff --git a/fs/xfs/xfs_inode.c b/fs/xfs/xfs_inode.c index 64b9bf334806..7ac8247b5498 100644 --- a/fs/xfs/xfs_inode.c +++ b/fs/xfs/xfs_inode.c @@ -977,6 +977,7 @@ xfs_create( struct xfs_trans_res *tres; uint resblks; xfs_ino_t ino; + struct user_namespace *fs_userns = &init_user_ns; trace_xfs_create(dp, name); @@ -988,8 +989,8 @@ xfs_create( /* * Make sure that we have allocated dquot(s) on disk. */ - error = xfs_qm_vop_dqalloc(dp, mapped_fsuid(mnt_userns), - mapped_fsgid(mnt_userns), prid, + error = xfs_qm_vop_dqalloc(dp, mapped_fsuid(mnt_userns, fs_userns), + mapped_fsgid(mnt_userns, fs_userns), prid, XFS_QMOPT_QUOTALL | XFS_QMOPT_INHERIT, &udqp, &gdqp, &pdqp); if (error) @@ -1133,6 +1134,7 @@ xfs_create_tmpfile( struct xfs_trans_res *tres; uint resblks; xfs_ino_t ino; + struct user_namespace *fs_userns = &init_user_ns; if (xfs_is_shutdown(mp)) return -EIO; @@ -1142,8 +1144,8 @@ xfs_create_tmpfile( /* * Make sure that we have allocated dquot(s) on disk. */ - error = xfs_qm_vop_dqalloc(dp, mapped_fsuid(mnt_userns), - mapped_fsgid(mnt_userns), prid, + error = xfs_qm_vop_dqalloc(dp, mapped_fsuid(mnt_userns, fs_userns), + mapped_fsgid(mnt_userns, fs_userns), prid, XFS_QMOPT_QUOTALL | XFS_QMOPT_INHERIT, &udqp, &gdqp, &pdqp); if (error) diff --git a/fs/xfs/xfs_symlink.c b/fs/xfs/xfs_symlink.c index fc2c6a404647..bf19c111771c 100644 --- a/fs/xfs/xfs_symlink.c +++ b/fs/xfs/xfs_symlink.c @@ -163,6 +163,7 @@ xfs_symlink( struct xfs_dquot *pdqp = NULL; uint resblks; xfs_ino_t ino; + struct user_namespace *fs_userns = &init_user_ns; *ipp = NULL; @@ -184,8 +185,8 @@ xfs_symlink( /* * Make sure that we have allocated dquot(s) on disk. */ - error = xfs_qm_vop_dqalloc(dp, mapped_fsuid(mnt_userns), - mapped_fsgid(mnt_userns), prid, + error = xfs_qm_vop_dqalloc(dp, mapped_fsuid(mnt_userns, fs_userns), + mapped_fsgid(mnt_userns, fs_userns), prid, XFS_QMOPT_QUOTALL | XFS_QMOPT_INHERIT, &udqp, &gdqp, &pdqp); if (error) diff --git a/include/linux/fs.h b/include/linux/fs.h index b46fb111017b..6ccb0e7f8801 100644 --- a/include/linux/fs.h +++ b/include/linux/fs.h @@ -1664,7 +1664,7 @@ static inline kgid_t i_gid_into_mnt(struct user_namespace *mnt_userns, static inline void inode_fsuid_set(struct inode *inode, struct user_namespace *mnt_userns) { - inode->i_uid = mapped_fsuid(mnt_userns); + inode->i_uid = mapped_fsuid(mnt_userns, &init_user_ns); } /** @@ -1678,7 +1678,7 @@ static inline void inode_fsuid_set(struct inode *inode, static inline void inode_fsgid_set(struct inode *inode, struct user_namespace *mnt_userns) { - inode->i_gid = mapped_fsgid(mnt_userns); + inode->i_gid = mapped_fsgid(mnt_userns, &init_user_ns); } /** @@ -1699,10 +1699,10 @@ static inline bool fsuidgid_has_mapping(struct super_block *sb, kuid_t kuid; kgid_t kgid; - kuid = mapped_fsuid(mnt_userns); + kuid = mapped_fsuid(mnt_userns, &init_user_ns); if (!uid_valid(kuid)) return false; - kgid = mapped_fsgid(mnt_userns); + kgid = mapped_fsgid(mnt_userns, &init_user_ns); if (!gid_valid(kgid)) return false; return kuid_has_mapping(fs_userns, kuid) && diff --git a/include/linux/mnt_mapping.h b/include/linux/mnt_mapping.h index f55b62fd27ae..40e3ad7ee795 100644 --- a/include/linux/mnt_mapping.h +++ b/include/linux/mnt_mapping.h @@ -196,6 +196,7 @@ static inline kgid_t mapped_kgid_user(struct user_namespace *mnt_userns, /** * mapped_fsuid - return caller's fsuid mapped up into a mnt_userns * @mnt_userns: the mount's idmapping + * @fs_userns: the filesystem's idmapping * * Use this helper to initialize a new vfs or filesystem object based on * the caller's fsuid. A common example is initializing the i_uid field of @@ -205,14 +206,16 @@ static inline kgid_t mapped_kgid_user(struct user_namespace *mnt_userns, * * Return: the caller's current fsuid mapped up according to @mnt_userns. */ -static inline kuid_t mapped_fsuid(struct user_namespace *mnt_userns) +static inline kuid_t mapped_fsuid(struct user_namespace *mnt_userns, + struct user_namespace *fs_userns) { - return mapped_kuid_user(mnt_userns, &init_user_ns, current_fsuid()); + return mapped_kuid_user(mnt_userns, fs_userns, current_fsuid()); } /** * mapped_fsgid - return caller's fsgid mapped up into a mnt_userns * @mnt_userns: the mount's idmapping + * @fs_userns: the filesystem's idmapping * * Use this helper to initialize a new vfs or filesystem object based on * the caller's fsgid. A common example is initializing the i_gid field of @@ -222,9 +225,10 @@ static inline kuid_t mapped_fsuid(struct user_namespace *mnt_userns) * * Return: the caller's current fsgid mapped up according to @mnt_userns. */ -static inline kgid_t mapped_fsgid(struct user_namespace *mnt_userns) +static inline kgid_t mapped_fsgid(struct user_namespace *mnt_userns, + struct user_namespace *fs_userns) { - return mapped_kgid_user(mnt_userns, &init_user_ns, current_fsgid()); + return mapped_kgid_user(mnt_userns, fs_userns, current_fsgid()); } #endif /* _LINUX_MNT_MAPPING_H */ From patchwork Tue Nov 23 11:42:26 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Christian Brauner X-Patchwork-Id: 12633995 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 A2010C433EF for ; Tue, 23 Nov 2021 11:43:07 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S236424AbhKWLqO (ORCPT ); Tue, 23 Nov 2021 06:46:14 -0500 Received: from mail.kernel.org ([198.145.29.99]:37610 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S236433AbhKWLqL (ORCPT ); Tue, 23 Nov 2021 06:46:11 -0500 Received: by mail.kernel.org (Postfix) with ESMTPSA id 9A32261027; Tue, 23 Nov 2021 11:43:02 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1637667784; bh=T7f6WBqgp2U6M4loI06LQzaawNL0KiQoFLP49st20J4=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=tMRQ8dYZ051wxIgV/Iq9lTaFOJavMHRRB/UQhQjkakInuk6fB3PC0AtRbmOPYu3T1 MPBEdqxEvpNUwUCPvCyLZG92sFFYhfO1BRIU0vmUt2g6Fge6CHh6iDsH1s+fxxlWui OucJ1KG6oqWBGdO7itG4ouNxL4ah+MDreLtzI/yVMCeIAS+IJlrjVSBvYUJREjqlOm GjXHxxE83CQac4XTEenhuqGmUCy26swgOmtsl9/44eWgp3rwZ1HLWDxHnP90FMZFv7 dFzJHOErQtCQiXFM2oqxBA/C8Un5yUwmLPhYwUGghZlT2glq/LVhDEnmAPSZZPLgzb +7AT6PKK3FSAw== From: Christian Brauner To: Christoph Hellwig Cc: Seth Forshee , Al Viro , linux-fsdevel@vger.kernel.org, Christian Brauner Subject: [PATCH 09/10] fs: add i_user_ns() helper Date: Tue, 23 Nov 2021 12:42:26 +0100 Message-Id: <20211123114227.3124056-10-brauner@kernel.org> X-Mailer: git-send-email 2.30.2 In-Reply-To: <20211123114227.3124056-1-brauner@kernel.org> References: <20211123114227.3124056-1-brauner@kernel.org> MIME-Version: 1.0 X-Developer-Signature: v=1; a=openpgp-sha256; l=1922; h=from:subject; bh=57H4mwOXSX3LItSH+nEABlp+xgcA/0JQxXskSPgYjuI=; b=owGbwMvMwCU28Zj0gdSKO4sYT6slMSTOuVzm5MTGNft698rzh9OvWMgJuv/O67m+1vOuWbHFYV57 ycfuHaUsDGJcDLJiiiwO7Sbhcst5KjYbZWrAzGFlAhnCwMUpABOZ8IuR4eFvVbvt/Fdtmg/vVt3281 zI/VLHpfriVWpfE6U/qvkyezEyzM2PcMuSKowVfvrsZIVx/8nlfXpT9+RN2lBmeiEhz283DwA= X-Developer-Key: i=christian.brauner@ubuntu.com; a=openpgp; fpr=4880B8C9BD0E5106FC070F4F7B3C391EFEA93624 Precedence: bulk List-ID: X-Mailing-List: linux-fsdevel@vger.kernel.org From: Christian Brauner Since we'll be passing the filesystem's idmapping in even more places in the following patches and we do already dereference struct inode to get to the filesystem's idmapping multiple times add a tiny helper. Cc: Seth Forshee Cc: Christoph Hellwig Cc: Al Viro CC: linux-fsdevel@vger.kernel.org Signed-off-by: Christian Brauner Reviewed-by: Amir Goldstein --- include/linux/fs.h | 13 +++++++++---- 1 file changed, 9 insertions(+), 4 deletions(-) diff --git a/include/linux/fs.h b/include/linux/fs.h index 6ccb0e7f8801..c1780be923fa 100644 --- a/include/linux/fs.h +++ b/include/linux/fs.h @@ -1600,6 +1600,11 @@ struct super_block { struct list_head s_inodes_wb; /* writeback inodes */ } __randomize_layout; +static inline struct user_namespace *i_user_ns(const struct inode *inode) +{ + return inode->i_sb->s_user_ns; +} + /* Helper functions so that in most cases filesystems will * not need to deal directly with kuid_t and kgid_t and can * instead deal with the raw numeric values that are stored @@ -1607,22 +1612,22 @@ struct super_block { */ static inline uid_t i_uid_read(const struct inode *inode) { - return from_kuid(inode->i_sb->s_user_ns, inode->i_uid); + return from_kuid(i_user_ns(inode), inode->i_uid); } static inline gid_t i_gid_read(const struct inode *inode) { - return from_kgid(inode->i_sb->s_user_ns, inode->i_gid); + return from_kgid(i_user_ns(inode), inode->i_gid); } static inline void i_uid_write(struct inode *inode, uid_t uid) { - inode->i_uid = make_kuid(inode->i_sb->s_user_ns, uid); + inode->i_uid = make_kuid(i_user_ns(inode), uid); } static inline void i_gid_write(struct inode *inode, gid_t gid) { - inode->i_gid = make_kgid(inode->i_sb->s_user_ns, gid); + inode->i_gid = make_kgid(i_user_ns(inode), gid); } /** From patchwork Tue Nov 23 11:42:27 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Christian Brauner X-Patchwork-Id: 12633999 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 3BD1EC433FE for ; Tue, 23 Nov 2021 11:43:08 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S236439AbhKWLqP (ORCPT ); Tue, 23 Nov 2021 06:46:15 -0500 Received: from mail.kernel.org ([198.145.29.99]:37628 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S236453AbhKWLqN (ORCPT ); Tue, 23 Nov 2021 06:46:13 -0500 Received: by mail.kernel.org (Postfix) with ESMTPSA id 8C98561039; Tue, 23 Nov 2021 11:43:04 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1637667786; bh=/kcNzYvf44u9u6nKC5M438Tq1IDdQhIplftJQ+xej3M=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=dJDJgy8ObbS13Doh1oBl4B9DkK6HPIkk6U+IO1noQuMqQoMcEmeSDvezASd/J0DdI Ok5x5QO7TSGVwKlDuAYHg++5mEEUDvvOjPf3gWRSwm1RTRYaNKRRzgo/LGfP7LiWOp A+ravUtbuRv67mXlmpImV8Z/xER46+D53lf/8AhTLFmLk364L+mP92HoCsXgsEyMGs p8ZnSRXYlXyS/5Em0qAEjd6jUhiTcpeJpC7LOr2j5d4pbdCsanH+SGaU5Qb5A6RXmO YLcbAyzbZmKCyUjT6ouwI8kRrzsFTbgXHAL+oq/GFG7YtcC2Xi9vGK0TT0cNhUgAp8 Y7kPeh9R/8tMA== From: Christian Brauner To: Christoph Hellwig Cc: Seth Forshee , Al Viro , linux-fsdevel@vger.kernel.org, Christian Brauner Subject: [PATCH 10/10] fs: support mapped mounts of mapped filesystems Date: Tue, 23 Nov 2021 12:42:27 +0100 Message-Id: <20211123114227.3124056-11-brauner@kernel.org> X-Mailer: git-send-email 2.30.2 In-Reply-To: <20211123114227.3124056-1-brauner@kernel.org> References: <20211123114227.3124056-1-brauner@kernel.org> MIME-Version: 1.0 X-Developer-Signature: v=1; a=openpgp-sha256; l=13433; h=from:subject; bh=oGtcaWBZHTIgpD3YrR7T+bB0JU2/pqPsg5oP0ktEGEs=; b=owGbwMvMwCU28Zj0gdSKO4sYT6slMSTOuVym2P5yzuPgZ7sfcXHvY53KVXWhL711ve57xcc2N2NP Loh73FHKwiDGxSArpsji0G4SLrecp2KzUaYGzBxWJpAhDFycAjCR0oWMDGdtbh3SeN5jtLiAXbp0Ps cKo1+1ZtOfpsv3VrEo+Nq/O8LwP3n3Ms1XyfefGsUpfQg6q1n0cn6+tevhFXuVHNMfN26q5AIA X-Developer-Key: i=christian.brauner@ubuntu.com; a=openpgp; fpr=4880B8C9BD0E5106FC070F4F7B3C391EFEA93624 Precedence: bulk List-ID: X-Mailing-List: linux-fsdevel@vger.kernel.org From: Christian Brauner In previous patches we added new and modified existing helpers to handle idmapped mounts of filesystems mounted with an idmapping. In this final patch we convert all relevant places in the vfs to actually pass the filesystem's idmapping into these helpers. With this the vfs is in shape to handle idmapped mounts of filesystems mounted with an idmapping. Note that this is just the generic infrastructure. Actually adding support for idmapped mounts to a filesystem mountable with an idmapping is follow-up work. In this patch we extend the definition of an idmapped mount from a mount that that has the initial idmapping attached to it to a mount that has an idmapping attached to it which is not the same as the idmapping the filesystem was mounted with. As before we do not allow the initial idmapping to be attached to a mount. In addition this patch prevents that the idmapping the filesystem was mounted with can be attached to a mount created based on this filesystem. This has multiple reasons and advantages. First, attaching the initial idmapping or the filesystem's idmapping doesn't make much sense as in both cases the values of the i_{g,u}id and other places where k{g,u}ids are used do not change. Second, a user that really wants to do this for whatever reason can just create a separate dedicated identical idmapping to attach to the mount. Third, we can continue to use the initial idmapping as an indicator that a mount is not idmapped allowing us to continue to keep passing the initial idmapping into the mapping helpers to tell them that something isn't an idmapped mount even if the filesystem is mounted with an idmapping. Apart from the generic places in the vfs the only other place we need to change is xfs since it makes use of mapped_fs{g,u}id() directly. Technically, this isn't even required since xfs doesn't support being mounted with an idmapping but it is cleaner to convert it properly. Cc: Seth Forshee Cc: Christoph Hellwig Cc: Al Viro CC: linux-fsdevel@vger.kernel.org Signed-off-by: Christian Brauner --- fs/namespace.c | 36 ++++++++++++++++++++++++------------ fs/open.c | 7 ++++--- fs/posix_acl.c | 8 ++++---- fs/xfs/xfs_inode.c | 4 ++-- fs/xfs/xfs_symlink.c | 2 +- include/linux/fs.h | 17 +++++++++-------- security/commoncap.c | 9 ++++----- 7 files changed, 48 insertions(+), 35 deletions(-) diff --git a/fs/namespace.c b/fs/namespace.c index 7d7b80b375a4..92f551b0469c 100644 --- a/fs/namespace.c +++ b/fs/namespace.c @@ -561,7 +561,7 @@ static void free_vfsmnt(struct mount *mnt) struct user_namespace *mnt_userns; mnt_userns = mnt_user_ns(&mnt->mnt); - if (mnt_userns != &init_user_ns) + if (!initial_mapping(mnt_userns)) put_user_ns(mnt_userns); kfree_const(mnt->mnt_devname); #ifdef CONFIG_SMP @@ -965,6 +965,7 @@ static struct mount *skip_mnt_tree(struct mount *p) struct vfsmount *vfs_create_mount(struct fs_context *fc) { struct mount *mnt; + struct user_namespace *fs_userns; if (!fc->root) return ERR_PTR(-EINVAL); @@ -982,6 +983,10 @@ struct vfsmount *vfs_create_mount(struct fs_context *fc) mnt->mnt_mountpoint = mnt->mnt.mnt_root; mnt->mnt_parent = mnt; + fs_userns = mnt->mnt.mnt_sb->s_user_ns; + if (!initial_mapping(fs_userns)) + mnt->mnt.mnt_userns = get_user_ns(fs_userns); + lock_mount_hash(); list_add_tail(&mnt->mnt_instance, &mnt->mnt.mnt_sb->s_mounts); unlock_mount_hash(); @@ -1072,7 +1077,7 @@ static struct mount *clone_mnt(struct mount *old, struct dentry *root, atomic_inc(&sb->s_active); mnt->mnt.mnt_userns = mnt_user_ns(&old->mnt); - if (mnt->mnt.mnt_userns != &init_user_ns) + if (!initial_mapping(mnt->mnt.mnt_userns)) mnt->mnt.mnt_userns = get_user_ns(mnt->mnt.mnt_userns); mnt->mnt.mnt_sb = sb; mnt->mnt.mnt_root = dget(root); @@ -3927,10 +3932,18 @@ static unsigned int recalc_flags(struct mount_kattr *kattr, struct mount *mnt) static int can_idmap_mount(const struct mount_kattr *kattr, struct mount *mnt) { struct vfsmount *m = &mnt->mnt; + struct user_namespace *fs_userns = m->mnt_sb->s_user_ns; if (!kattr->mnt_userns) return 0; + /* + * Creating an idmapped mount with the filesystem wide idmapping + * doesn't make sense so block that. We don't allow mushy semantics. + */ + if (kattr->mnt_userns == fs_userns) + return -EINVAL; + /* * Once a mount has been idmapped we don't allow it to change its * mapping. It makes things simpler and callers can just create @@ -3943,12 +3956,8 @@ static int can_idmap_mount(const struct mount_kattr *kattr, struct mount *mnt) if (!(m->mnt_sb->s_type->fs_flags & FS_ALLOW_IDMAP)) return -EINVAL; - /* Don't yet support filesystem mountable in user namespaces. */ - if (m->mnt_sb->s_user_ns != &init_user_ns) - return -EINVAL; - /* We're not controlling the superblock. */ - if (!capable(CAP_SYS_ADMIN)) + if (!ns_capable(fs_userns, CAP_SYS_ADMIN)) return -EPERM; /* Mount has already been visible in the filesystem hierarchy. */ @@ -4133,13 +4142,16 @@ static int build_mount_idmapped(const struct mount_attr *attr, size_t usize, } /* - * The init_user_ns is used to indicate that a vfsmount is not idmapped. - * This is simpler than just having to treat NULL as unmapped. Users - * wanting to idmap a mount to init_user_ns can just use a namespace - * with an identity mapping. + * The initial idmapping cannot be used to create an idmapped + * mount. Attaching the initial idmapping doesn't make much sense + * as it is an identity mapping. A user can just create a dedicated + * identity mapping to achieve the same result. We also use the + * initial idmapping as an indicator of a mount that is not + * idmapped. It can simply be passed into helpers that are aware of + * idmapped mounts as a convenient shortcut. */ mnt_userns = container_of(ns, struct user_namespace, ns); - if (mnt_userns == &init_user_ns) { + if (initial_mapping(mnt_userns)) { err = -EPERM; goto out_fput; } diff --git a/fs/open.c b/fs/open.c index 64f799d96356..fb17d58db89c 100644 --- a/fs/open.c +++ b/fs/open.c @@ -640,7 +640,7 @@ SYSCALL_DEFINE2(chmod, const char __user *, filename, umode_t, mode) int chown_common(const struct path *path, uid_t user, gid_t group) { - struct user_namespace *mnt_userns; + struct user_namespace *mnt_userns, *fs_userns; struct inode *inode = path->dentry->d_inode; struct inode *delegated_inode = NULL; int error; @@ -652,8 +652,9 @@ int chown_common(const struct path *path, uid_t user, gid_t group) gid = make_kgid(current_user_ns(), group); mnt_userns = mnt_user_ns(path->mnt); - uid = mapped_kuid_user(mnt_userns, &init_user_ns, uid); - gid = mapped_kgid_user(mnt_userns, &init_user_ns, gid); + fs_userns = i_user_ns(inode); + uid = mapped_kuid_user(mnt_userns, fs_userns, uid); + gid = mapped_kgid_user(mnt_userns, fs_userns, gid); retry_deleg: newattrs.ia_valid = ATTR_CTIME; diff --git a/fs/posix_acl.c b/fs/posix_acl.c index e45b3ffb6de1..edae00c5fb6d 100644 --- a/fs/posix_acl.c +++ b/fs/posix_acl.c @@ -375,8 +375,8 @@ posix_acl_permission(struct user_namespace *mnt_userns, struct inode *inode, break; case ACL_USER: uid = mapped_kuid_fs(mnt_userns, - &init_user_ns, - pa->e_uid); + i_user_ns(inode), + pa->e_uid); if (uid_eq(uid, current_fsuid())) goto mask; break; @@ -390,8 +390,8 @@ posix_acl_permission(struct user_namespace *mnt_userns, struct inode *inode, break; case ACL_GROUP: gid = mapped_kgid_fs(mnt_userns, - &init_user_ns, - pa->e_gid); + i_user_ns(inode), + pa->e_gid); if (in_group_p(gid)) { found = 1; if ((pa->e_perm & want) == want) diff --git a/fs/xfs/xfs_inode.c b/fs/xfs/xfs_inode.c index 7ac8247b5498..bafa3e1b3a79 100644 --- a/fs/xfs/xfs_inode.c +++ b/fs/xfs/xfs_inode.c @@ -977,7 +977,7 @@ xfs_create( struct xfs_trans_res *tres; uint resblks; xfs_ino_t ino; - struct user_namespace *fs_userns = &init_user_ns; + struct user_namespace *fs_userns = i_user_ns(VFS_I(dp)); trace_xfs_create(dp, name); @@ -1134,7 +1134,7 @@ xfs_create_tmpfile( struct xfs_trans_res *tres; uint resblks; xfs_ino_t ino; - struct user_namespace *fs_userns = &init_user_ns; + struct user_namespace *fs_userns = i_user_ns(VFS_I(dp)); if (xfs_is_shutdown(mp)) return -EIO; diff --git a/fs/xfs/xfs_symlink.c b/fs/xfs/xfs_symlink.c index bf19c111771c..612a5c86cccb 100644 --- a/fs/xfs/xfs_symlink.c +++ b/fs/xfs/xfs_symlink.c @@ -163,7 +163,7 @@ xfs_symlink( struct xfs_dquot *pdqp = NULL; uint resblks; xfs_ino_t ino; - struct user_namespace *fs_userns = &init_user_ns; + struct user_namespace *fs_userns = i_user_ns(VFS_I(dp)); *ipp = NULL; diff --git a/include/linux/fs.h b/include/linux/fs.h index c1780be923fa..87a71bf2c6b5 100644 --- a/include/linux/fs.h +++ b/include/linux/fs.h @@ -1641,7 +1641,7 @@ static inline void i_gid_write(struct inode *inode, gid_t gid) static inline kuid_t i_uid_into_mnt(struct user_namespace *mnt_userns, const struct inode *inode) { - return mapped_kuid_fs(mnt_userns, &init_user_ns, inode->i_uid); + return mapped_kuid_fs(mnt_userns, i_user_ns(inode), inode->i_uid); } /** @@ -1655,7 +1655,7 @@ static inline kuid_t i_uid_into_mnt(struct user_namespace *mnt_userns, static inline kgid_t i_gid_into_mnt(struct user_namespace *mnt_userns, const struct inode *inode) { - return mapped_kgid_fs(mnt_userns, &init_user_ns, inode->i_gid); + return mapped_kgid_fs(mnt_userns, i_user_ns(inode), inode->i_gid); } /** @@ -1669,7 +1669,7 @@ static inline kgid_t i_gid_into_mnt(struct user_namespace *mnt_userns, static inline void inode_fsuid_set(struct inode *inode, struct user_namespace *mnt_userns) { - inode->i_uid = mapped_fsuid(mnt_userns, &init_user_ns); + inode->i_uid = mapped_fsuid(mnt_userns, i_user_ns(inode)); } /** @@ -1683,7 +1683,7 @@ static inline void inode_fsuid_set(struct inode *inode, static inline void inode_fsgid_set(struct inode *inode, struct user_namespace *mnt_userns) { - inode->i_gid = mapped_fsgid(mnt_userns, &init_user_ns); + inode->i_gid = mapped_fsgid(mnt_userns, i_user_ns(inode)); } /** @@ -1704,10 +1704,10 @@ static inline bool fsuidgid_has_mapping(struct super_block *sb, kuid_t kuid; kgid_t kgid; - kuid = mapped_fsuid(mnt_userns, &init_user_ns); + kuid = mapped_fsuid(mnt_userns, fs_userns); if (!uid_valid(kuid)) return false; - kgid = mapped_fsgid(mnt_userns, &init_user_ns); + kgid = mapped_fsgid(mnt_userns, fs_userns); if (!gid_valid(kgid)) return false; return kuid_has_mapping(fs_userns, kuid) && @@ -2654,13 +2654,14 @@ static inline struct user_namespace *file_mnt_user_ns(struct file *file) * is_mapped_mnt - check whether a mount is mapped * @mnt: the mount to check * - * If @mnt has an idmapping attached to it @mnt is mapped. + * If @mnt has an idmapping attached different from the + * filesystem's idmapping then @mnt is mapped. * * Return: true if mount is mapped, false if not. */ static inline bool is_mapped_mnt(const struct vfsmount *mnt) { - return mnt_user_ns(mnt) != &init_user_ns; + return mnt_user_ns(mnt) != mnt->mnt_sb->s_user_ns; } extern long vfs_truncate(const struct path *, loff_t); diff --git a/security/commoncap.c b/security/commoncap.c index 77d319f62710..e9b71eefe97b 100644 --- a/security/commoncap.c +++ b/security/commoncap.c @@ -418,7 +418,7 @@ int cap_inode_getsecurity(struct user_namespace *mnt_userns, kroot = make_kuid(fs_ns, root); /* If this is an idmapped mount shift the kuid. */ - kroot = mapped_kuid_fs(mnt_userns, &init_user_ns, kroot); + kroot = mapped_kuid_fs(mnt_userns, fs_ns, kroot); /* If the root kuid maps to a valid uid in current ns, then return * this as a nscap. */ @@ -555,13 +555,12 @@ int cap_convert_nscap(struct user_namespace *mnt_userns, struct dentry *dentry, return -EINVAL; if (!capable_wrt_inode_uidgid(mnt_userns, inode, CAP_SETFCAP)) return -EPERM; - if (size == XATTR_CAPS_SZ_2 && (mnt_userns == &init_user_ns)) + if (size == XATTR_CAPS_SZ_2 && (mnt_userns == fs_ns)) if (ns_capable(inode->i_sb->s_user_ns, CAP_SETFCAP)) /* user is privileged, just write the v2 */ return size; - rootid = rootid_from_xattr(*ivalue, size, task_ns, mnt_userns, - &init_user_ns); + rootid = rootid_from_xattr(*ivalue, size, task_ns, mnt_userns, fs_ns); if (!uid_valid(rootid)) return -EINVAL; @@ -702,7 +701,7 @@ int get_vfs_caps_from_disk(struct user_namespace *mnt_userns, /* Limit the caps to the mounter of the filesystem * or the more limited uid specified in the xattr. */ - rootkuid = mapped_kuid_fs(mnt_userns, &init_user_ns, rootkuid); + rootkuid = mapped_kuid_fs(mnt_userns, fs_ns, rootkuid); if (!rootid_owns_currentns(rootkuid)) return -ENODATA;