From: Christian Brauner <christian.brauner@ubuntu.com>
To: Alexander Viro <viro@zeniv.linux.org.uk>,
Christoph Hellwig <hch@lst.de>,
linux-fsdevel@vger.kernel.org
Cc: Lennart Poettering <lennart@poettering.net>,
Mimi Zohar <zohar@linux.ibm.com>,
James Bottomley <James.Bottomley@hansenpartnership.com>,
Andreas Dilger <adilger.kernel@dilger.ca>,
containers@lists.linux-foundation.org,
Tycho Andersen <tycho@tycho.ws>, Paul Moore <paul@paul-moore.com>,
Jonathan Corbet <corbet@lwn.net>,
smbarber@chromium.org, linux-ext4@vger.kernel.org,
Mrunal Patel <mpatel@redhat.com>,
Kees Cook <keescook@chromium.org>, Arnd Bergmann <arnd@arndb.de>,
selinux@vger.kernel.org, Josh Triplett <josh@joshtriplett.org>,
Seth Forshee <seth.forshee@canonical.com>,
Aleksa Sarai <cyphar@cyphar.com>,
Andy Lutomirski <luto@kernel.org>,
OGAWA Hirofumi <hirofumi@mail.parknet.co.jp>,
Geoffrey Thomas <geofft@ldpreload.com>,
David Howells <dhowells@redhat.com>,
John Johansen <john.johansen@canonical.com>,
Theodore Tso <tytso@mit.edu>,
Dmitry Kasatkin <dmitry.kasatkin@gmail.com>,
Stephen Smalley <stephen.smalley.work@gmail.com>,
linux-xfs@vger.kernel.org, linux-security-module@vger.kernel.org,
"Eric W. Biederman" <ebiederm@xmission.com>,
linux-api@vger.kernel.org,
Casey Schaufler <casey@schaufler-ca.com>,
Alban Crequy <alban@kinvolk.io>,
linux-integrity@vger.kernel.org,
Linus Torvalds <torvalds@linux-foundation.org>,
Todd Kjos <tkjos@google.com>
Subject: [PATCH v6 37/40] fat: handle idmapped mounts
Date: Thu, 21 Jan 2021 14:19:56 +0100 [thread overview]
Message-ID: <20210121131959.646623-38-christian.brauner@ubuntu.com> (raw)
In-Reply-To: <20210121131959.646623-1-christian.brauner@ubuntu.com>
Let fat handle idmapped mounts. This allows to have the same fat mount
appear in multiple locations with different id mappings. This allows to
expose a vfat formatted USB stick to multiple user with different ids on
the host or in user namespaces allowing for dac permissions:
mount -o uid=1000,gid=1000 /dev/sdb /mnt
u1001@f2-vm:/lower1$ ls -ln /mnt/
total 4
-rwxr-xr-x 1 1000 1000 4 Oct 28 03:44 aaa
-rwxr-xr-x 1 1000 1000 0 Oct 28 01:09 bbb
-rwxr-xr-x 1 1000 1000 0 Oct 28 01:10 ccc
-rwxr-xr-x 1 1000 1000 0 Oct 28 03:46 ddd
-rwxr-xr-x 1 1000 1000 0 Oct 28 04:01 eee
mount-idmapped --map-mount b:1000:1001:1
u1001@f2-vm:/lower1$ ls -ln /lower1/
total 4
-rwxr-xr-x 1 1001 1001 4 Oct 28 03:44 aaa
-rwxr-xr-x 1 1001 1001 0 Oct 28 01:09 bbb
-rwxr-xr-x 1 1001 1001 0 Oct 28 01:10 ccc
-rwxr-xr-x 1 1001 1001 0 Oct 28 03:46 ddd
-rwxr-xr-x 1 1001 1001 0 Oct 28 04:01 eee
u1001@f2-vm:/lower1$ touch /lower1/fff
u1001@f2-vm:/lower1$ ls -ln /lower1/fff
-rwxr-xr-x 1 1001 1001 0 Oct 28 04:03 /lower1/fff
u1001@f2-vm:/lower1$ ls -ln /mnt/fff
-rwxr-xr-x 1 1000 1000 0 Oct 28 04:03 /mnt/fff
Link: https://lore.kernel.org/r/20210112220124.837960-36-christian.brauner@ubuntu.com
Cc: Christoph Hellwig <hch@lst.de>
Cc: David Howells <dhowells@redhat.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: linux-fsdevel@vger.kernel.org
Signed-off-by: Christian Brauner <christian.brauner@ubuntu.com>
---
/* v2 */
unchanged
/* v3 */
unchanged
/* v4 */
- Mauricio Vásquez Bernal <mauricio@kinvolk.io>:
- Fix mount example in commit message.
- Serge Hallyn <serge@hallyn.com>:
- Use "mnt_userns" to refer to a vfsmount's userns everywhere to make
terminology consistent.
/* v5 */
unchanged
base-commit: 7c53f6b671f4aba70ff15e1b05148b10d58c2837
/* v6 */
unchanged
base-commit: 19c329f6808995b142b3966301f217c831e7cf31
---
fs/fat/file.c | 15 ++++++++-------
fs/fat/namei_msdos.c | 2 +-
fs/fat/namei_vfat.c | 2 +-
3 files changed, 10 insertions(+), 9 deletions(-)
diff --git a/fs/fat/file.c b/fs/fat/file.c
index dd73d1b70c55..da7c56234189 100644
--- a/fs/fat/file.c
+++ b/fs/fat/file.c
@@ -398,7 +398,7 @@ int fat_getattr(struct user_namespace *mnt_userns, const struct path *path,
struct kstat *stat, u32 request_mask, unsigned int flags)
{
struct inode *inode = d_inode(path->dentry);
- generic_fillattr(&init_user_ns, inode, stat);
+ generic_fillattr(mnt_userns, inode, stat);
stat->blksize = MSDOS_SB(inode->i_sb)->cluster_size;
if (MSDOS_SB(inode->i_sb)->options.nfs == FAT_NFS_NOSTALE_RO) {
@@ -447,12 +447,13 @@ static int fat_sanitize_mode(const struct msdos_sb_info *sbi,
return 0;
}
-static int fat_allow_set_time(struct msdos_sb_info *sbi, struct inode *inode)
+static int fat_allow_set_time(struct user_namespace *mnt_userns,
+ struct msdos_sb_info *sbi, struct inode *inode)
{
umode_t allow_utime = sbi->options.allow_utime;
- if (!uid_eq(current_fsuid(), inode->i_uid)) {
- if (in_group_p(inode->i_gid))
+ if (!uid_eq(current_fsuid(), i_uid_into_mnt(mnt_userns, inode))) {
+ if (in_group_p(i_gid_into_mnt(mnt_userns, inode)))
allow_utime >>= 3;
if (allow_utime & MAY_WRITE)
return 1;
@@ -477,11 +478,11 @@ int fat_setattr(struct user_namespace *mnt_userns, struct dentry *dentry,
/* Check for setting the inode time. */
ia_valid = attr->ia_valid;
if (ia_valid & TIMES_SET_FLAGS) {
- if (fat_allow_set_time(sbi, inode))
+ if (fat_allow_set_time(mnt_userns, sbi, inode))
attr->ia_valid &= ~TIMES_SET_FLAGS;
}
- error = setattr_prepare(&init_user_ns, dentry, attr);
+ error = setattr_prepare(mnt_userns, dentry, attr);
attr->ia_valid = ia_valid;
if (error) {
if (sbi->options.quiet)
@@ -551,7 +552,7 @@ int fat_setattr(struct user_namespace *mnt_userns, struct dentry *dentry,
fat_truncate_time(inode, &attr->ia_mtime, S_MTIME);
attr->ia_valid &= ~(ATTR_ATIME|ATTR_CTIME|ATTR_MTIME);
- setattr_copy(&init_user_ns, inode, attr);
+ setattr_copy(mnt_userns, inode, attr);
mark_inode_dirty(inode);
out:
return error;
diff --git a/fs/fat/namei_msdos.c b/fs/fat/namei_msdos.c
index a8f3375d9d10..efba301d68ae 100644
--- a/fs/fat/namei_msdos.c
+++ b/fs/fat/namei_msdos.c
@@ -667,7 +667,7 @@ static struct file_system_type msdos_fs_type = {
.name = "msdos",
.mount = msdos_mount,
.kill_sb = kill_block_super,
- .fs_flags = FS_REQUIRES_DEV,
+ .fs_flags = FS_REQUIRES_DEV | FS_ALLOW_IDMAP,
};
MODULE_ALIAS_FS("msdos");
diff --git a/fs/fat/namei_vfat.c b/fs/fat/namei_vfat.c
index 23936ecf79a5..5369d82e0bfb 100644
--- a/fs/fat/namei_vfat.c
+++ b/fs/fat/namei_vfat.c
@@ -1063,7 +1063,7 @@ static struct file_system_type vfat_fs_type = {
.name = "vfat",
.mount = vfat_mount,
.kill_sb = kill_block_super,
- .fs_flags = FS_REQUIRES_DEV,
+ .fs_flags = FS_REQUIRES_DEV | FS_ALLOW_IDMAP,
};
MODULE_ALIAS_FS("vfat");
--
2.30.0
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next prev parent reply other threads:[~2021-01-21 13:31 UTC|newest]
Thread overview: 80+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-01-21 13:19 [PATCH v6 00/40] idmapped mounts Christian Brauner
2021-01-21 13:19 ` [PATCH v6 01/40] mount: attach mappings to mounts Christian Brauner
2021-01-21 13:19 ` [PATCH v6 02/40] fs: add id translation helpers Christian Brauner
2021-03-13 0:05 ` Vivek Goyal
2021-01-21 13:19 ` [PATCH v6 03/40] fs: add file and path permissions helpers Christian Brauner
2021-01-22 2:55 ` James Morris
2021-01-21 13:19 ` [PATCH v6 04/40] capability: handle idmapped mounts Christian Brauner
2021-01-22 2:57 ` James Morris
2021-01-21 13:19 ` [PATCH v6 05/39] namei: make permission helpers idmapped mount aware Christian Brauner
2021-01-22 3:02 ` James Morris
2021-01-22 22:26 ` J. Bruce Fields
2021-01-23 13:09 ` Christian Brauner
2021-01-24 22:18 ` J. Bruce Fields
2021-01-24 22:44 ` Christian Brauner
2021-01-21 13:19 ` [PATCH v6 06/40] inode: make init and " Christian Brauner
2021-01-22 3:10 ` James Morris
2021-01-21 13:19 ` [PATCH v6 07/40] attr: handle idmapped mounts Christian Brauner
2021-01-21 13:19 ` [PATCH v6 08/40] acl: " Christian Brauner
2021-01-21 13:19 ` [PATCH v6 09/40] xattr: " Christian Brauner
2021-01-22 3:21 ` James Morris
2021-01-21 13:19 ` [PATCH v6 10/40] commoncap: " Christian Brauner
2021-01-22 3:27 ` James Morris
2021-01-21 13:19 ` [PATCH v6 11/40] stat: " Christian Brauner
2021-01-22 3:28 ` James Morris
2021-01-21 13:19 ` [PATCH v6 12/40] namei: handle idmapped mounts in may_*() helpers Christian Brauner
2021-01-22 3:47 ` James Morris
2021-01-21 13:19 ` [PATCH v6 13/40] namei: introduce struct renamedata Christian Brauner
2021-01-21 13:19 ` [PATCH v6 14/40] namei: prepare for idmapped mounts Christian Brauner
2021-01-21 13:19 ` [PATCH v6 15/40] open: handle idmapped mounts in do_truncate() Christian Brauner
2021-01-22 17:20 ` Christoph Hellwig
2021-01-21 13:19 ` [PATCH v6 16/40] open: handle idmapped mounts Christian Brauner
2021-01-22 4:14 ` James Morris
2021-01-22 17:21 ` Christoph Hellwig
2021-01-21 13:19 ` [PATCH v6 17/40] af_unix: " Christian Brauner
2021-01-22 4:14 ` James Morris
2021-01-21 13:19 ` [PATCH v6 18/40] utimes: " Christian Brauner
2021-01-22 4:15 ` James Morris
2021-01-21 13:19 ` [PATCH v6 19/40] fcntl: " Christian Brauner
2021-01-22 4:17 ` James Morris
2021-01-21 13:19 ` [PATCH v6 20/40] init: " Christian Brauner
2021-01-22 17:23 ` Christoph Hellwig
2021-01-21 13:19 ` [PATCH v6 21/40] ioctl: " Christian Brauner
2021-01-22 4:33 ` James Morris
2021-01-21 13:19 ` [PATCH v6 22/40] would_dump: " Christian Brauner
2021-01-21 13:19 ` [PATCH v6 23/40] exec: " Christian Brauner
2021-01-22 4:35 ` James Morris
2021-01-25 16:39 ` Eric W. Biederman
2021-01-25 16:44 ` Christian Brauner
2021-01-25 17:03 ` Serge E. Hallyn
2021-01-25 17:06 ` Christian Brauner
2021-01-27 5:50 ` Serge E. Hallyn
2021-01-21 13:19 ` [PATCH v6 24/40] fs: make helpers idmap mount aware Christian Brauner
2021-01-21 13:19 ` [PATCH v6 25/40] apparmor: handle idmapped mounts Christian Brauner
2021-01-21 13:19 ` [PATCH v6 26/39] ima: " Christian Brauner
2021-01-21 13:19 ` [PATCH v6 27/40] ecryptfs: do not mount on top of " Christian Brauner
2021-01-22 4:37 ` James Morris
2021-01-21 13:19 ` [PATCH v6 28/40] overlayfs: " Christian Brauner
2021-01-22 4:38 ` James Morris
2021-01-21 13:19 ` [PATCH v6 29/40] namespace: take lock_mount_hash() directly when changing flags Christian Brauner
2021-01-21 13:19 ` [PATCH v6 30/40] mount: make {lock,unlock}_mount_hash() static Christian Brauner
2021-01-21 13:19 ` [PATCH v6 31/40] namespace: only take read lock in do_reconfigure_mnt() Christian Brauner
2021-01-21 13:19 ` [PATCH v6 32/40] fs: split out functions to hold writers Christian Brauner
2021-01-21 13:19 ` [PATCH v6 33/40] fs: add attr_flags_to_mnt_flags helper Christian Brauner
2021-01-21 13:19 ` [PATCH v6 34/40] fs: add mount_setattr() Christian Brauner
2021-01-21 13:19 ` [PATCH v6 35/40] fs: introduce MOUNT_ATTR_IDMAP Christian Brauner
2021-01-22 17:33 ` Christoph Hellwig
2021-01-22 17:34 ` Christoph Hellwig
2021-01-21 13:19 ` [PATCH v6 36/40] tests: add mount_setattr() selftests Christian Brauner
2021-01-21 13:19 ` Christian Brauner [this message]
2021-01-21 13:19 ` [PATCH v6 38/40] ext4: support idmapped mounts Christian Brauner
2021-01-21 13:19 ` [PATCH v6 39/40] xfs: " Christian Brauner
2021-03-01 20:05 ` Darrick J. Wong
2021-03-01 20:46 ` Christian Brauner
2021-03-03 7:01 ` Christoph Hellwig
2021-01-21 13:19 ` [PATCH v6 40/40] generic/622: add fstests for " Christian Brauner
2021-01-27 5:40 ` [PATCH v6 00/40] " Serge E. Hallyn
2021-03-03 13:24 ` [PATCH v6 09/40] xattr: handle " David Howells
2021-03-03 14:05 ` Christian Brauner
2021-03-03 14:45 ` David Howells
2021-03-03 16:15 ` Christian Brauner
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