From: Christian Brauner <christian.brauner@ubuntu.com>
To: Alexander Viro <viro@zeniv.linux.org.uk>,
Christoph Hellwig <hch@infradead.org>,
linux-fsdevel@vger.kernel.org
Cc: "John Johansen" <john.johansen@canonical.com>,
"James Morris" <jmorris@namei.org>,
"Mimi Zohar" <zohar@linux.ibm.com>,
"Dmitry Kasatkin" <dmitry.kasatkin@gmail.com>,
"Stephen Smalley" <stephen.smalley.work@gmail.com>,
"Casey Schaufler" <casey@schaufler-ca.com>,
"Arnd Bergmann" <arnd@arndb.de>,
"Andreas Dilger" <adilger.kernel@dilger.ca>,
"OGAWA Hirofumi" <hirofumi@mail.parknet.co.jp>,
"Geoffrey Thomas" <geofft@ldpreload.com>,
"Mrunal Patel" <mpatel@redhat.com>,
"Josh Triplett" <josh@joshtriplett.org>,
"Andy Lutomirski" <luto@kernel.org>,
"Amir Goldstein" <amir73il@gmail.com>,
"Miklos Szeredi" <miklos@szeredi.hu>,
"Theodore Tso" <tytso@mit.edu>, "Alban Crequy" <alban@kinvolk.io>,
"Tycho Andersen" <tycho@tycho.ws>,
"David Howells" <dhowells@redhat.com>,
"James Bottomley" <James.Bottomley@hansenpartnership.com>,
"Jann Horn" <jannh@google.com>,
"Seth Forshee" <seth.forshee@canonical.com>,
"Stéphane Graber" <stgraber@ubuntu.com>,
"Aleksa Sarai" <cyphar@cyphar.com>,
"Lennart Poettering" <lennart@poettering.net>,
"Eric W. Biederman" <ebiederm@xmission.com>,
smbarber@chromium.org, "Phil Estes" <estesp@gmail.com>,
"Serge Hallyn" <serge@hallyn.com>,
"Kees Cook" <keescook@chromium.org>,
"Todd Kjos" <tkjos@google.com>,
"Jonathan Corbet" <corbet@lwn.net>,
containers@lists.linux-foundation.org,
linux-security-module@vger.kernel.org, linux-api@vger.kernel.org,
linux-ext4@vger.kernel.org, linux-unionfs@vger.kernel.org,
linux-audit@redhat.com, linux-integrity@vger.kernel.org,
selinux@vger.kernel.org,
"Christian Brauner" <christian.brauner@ubuntu.com>
Subject: [PATCH 34/34] fat: handle idmapped mounts
Date: Thu, 29 Oct 2020 01:32:52 +0100 [thread overview]
Message-ID: <20201029003252.2128653-35-christian.brauner@ubuntu.com> (raw)
In-Reply-To: <20201029003252.2128653-1-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:
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
mount2 --idmap both: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
Signed-off-by: Christian Brauner <christian.brauner@ubuntu.com>
---
fs/fat/fat.h | 2 ++
fs/fat/file.c | 27 +++++++++++++++++++--------
fs/fat/namei_msdos.c | 7 +++++++
fs/fat/namei_vfat.c | 7 +++++++
4 files changed, 35 insertions(+), 8 deletions(-)
diff --git a/fs/fat/fat.h b/fs/fat/fat.h
index 922a0c6ba46c..56d661e93d2a 100644
--- a/fs/fat/fat.h
+++ b/fs/fat/fat.h
@@ -398,6 +398,8 @@ extern long fat_generic_ioctl(struct file *filp, unsigned int cmd,
extern const struct file_operations fat_file_operations;
extern const struct inode_operations fat_file_inode_operations;
extern int fat_setattr(struct dentry *dentry, struct iattr *attr);
+extern int fat_setattr_mapped(struct user_namespace *user_ns,
+ struct dentry *dentry, struct iattr *attr);
extern void fat_truncate_blocks(struct inode *inode, loff_t offset);
extern int fat_getattr(const struct path *path, struct kstat *stat,
u32 request_mask, unsigned int flags);
diff --git a/fs/fat/file.c b/fs/fat/file.c
index f9ee27cf4d7c..f97d46711b37 100644
--- a/fs/fat/file.c
+++ b/fs/fat/file.c
@@ -398,7 +398,7 @@ int fat_getattr(const struct path *path, struct kstat *stat,
u32 request_mask, unsigned int flags)
{
struct inode *inode = d_inode(path->dentry);
- generic_fillattr(inode, stat);
+ mapped_generic_fillattr(mnt_user_ns(path->mnt), 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 *user_ns,
+ 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(user_ns, inode))) {
+ if (in_group_p(i_gid_into_mnt(user_ns, inode)))
allow_utime >>= 3;
if (allow_utime & MAY_WRITE)
return 1;
@@ -466,7 +467,8 @@ static int fat_allow_set_time(struct msdos_sb_info *sbi, struct inode *inode)
/* valid file mode bits */
#define FAT_VALID_MODE (S_IFREG | S_IFDIR | S_IRWXUGO)
-int fat_setattr(struct dentry *dentry, struct iattr *attr)
+int fat_setattr_mapped(struct user_namespace *user_ns, struct dentry *dentry,
+ struct iattr *attr)
{
struct msdos_sb_info *sbi = MSDOS_SB(dentry->d_sb);
struct inode *inode = d_inode(dentry);
@@ -476,11 +478,11 @@ int fat_setattr(struct dentry *dentry, struct iattr *attr)
/* 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(user_ns, sbi, inode))
attr->ia_valid &= ~TIMES_SET_FLAGS;
}
- error = setattr_prepare(dentry, attr);
+ error = setattr_mapped_prepare(user_ns, dentry, attr);
attr->ia_valid = ia_valid;
if (error) {
if (sbi->options.quiet)
@@ -550,15 +552,24 @@ int fat_setattr(struct dentry *dentry, struct iattr *attr)
fat_truncate_time(inode, &attr->ia_mtime, S_MTIME);
attr->ia_valid &= ~(ATTR_ATIME|ATTR_CTIME|ATTR_MTIME);
- setattr_copy(inode, attr);
+ setattr_mapped_copy(user_ns, inode, attr);
mark_inode_dirty(inode);
out:
return error;
}
+EXPORT_SYMBOL_GPL(fat_setattr_mapped);
+
+int fat_setattr(struct dentry *dentry, struct iattr *attr)
+{
+ return fat_setattr_mapped(&init_user_ns, dentry, attr);
+}
EXPORT_SYMBOL_GPL(fat_setattr);
const struct inode_operations fat_file_inode_operations = {
.setattr = fat_setattr,
.getattr = fat_getattr,
.update_time = fat_update_time,
+#ifdef CONFIG_IDMAP_MOUNTS
+ .setattr_mapped = fat_setattr_mapped,
+#endif
};
diff --git a/fs/fat/namei_msdos.c b/fs/fat/namei_msdos.c
index 9d062886fbc1..4b89d27d128d 100644
--- a/fs/fat/namei_msdos.c
+++ b/fs/fat/namei_msdos.c
@@ -639,6 +639,9 @@ static const struct inode_operations msdos_dir_inode_operations = {
.setattr = fat_setattr,
.getattr = fat_getattr,
.update_time = fat_update_time,
+#ifdef CONFIG_IDMAP_MOUNTS
+ .setattr_mapped = fat_setattr_mapped,
+#endif
};
static void setup(struct super_block *sb)
@@ -665,7 +668,11 @@ static struct file_system_type msdos_fs_type = {
.name = "msdos",
.mount = msdos_mount,
.kill_sb = kill_block_super,
+#ifdef CONFIG_IDMAP_MOUNTS
+ .fs_flags = FS_REQUIRES_DEV | FS_ALLOW_IDMAP,
+#else
.fs_flags = FS_REQUIRES_DEV,
+#endif
};
MODULE_ALIAS_FS("msdos");
diff --git a/fs/fat/namei_vfat.c b/fs/fat/namei_vfat.c
index 0cdd0fb9f742..11fea59e1b77 100644
--- a/fs/fat/namei_vfat.c
+++ b/fs/fat/namei_vfat.c
@@ -1034,6 +1034,9 @@ static const struct inode_operations vfat_dir_inode_operations = {
.setattr = fat_setattr,
.getattr = fat_getattr,
.update_time = fat_update_time,
+#ifdef CONFIG_IDMAP_MOUNTS
+ .setattr_mapped = fat_setattr_mapped,
+#endif
};
static void setup(struct super_block *sb)
@@ -1062,7 +1065,11 @@ static struct file_system_type vfat_fs_type = {
.name = "vfat",
.mount = vfat_mount,
.kill_sb = kill_block_super,
+#ifdef CONFIG_IDMAP_MOUNTS
+ .fs_flags = FS_REQUIRES_DEV | FS_ALLOW_IDMAP,
+#else
.fs_flags = FS_REQUIRES_DEV,
+#endif
};
MODULE_ALIAS_FS("vfat");
--
2.29.0
next prev parent reply other threads:[~2020-10-29 0:42 UTC|newest]
Thread overview: 68+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-10-29 0:32 [PATCH 00/34] fs: idmapped mounts Christian Brauner
2020-10-29 0:32 ` [PATCH 01/34] namespace: take lock_mount_hash() directly when changing flags Christian Brauner
2020-11-01 14:41 ` Christoph Hellwig
2020-11-02 13:33 ` Christian Brauner
2020-10-29 0:32 ` [PATCH 02/34] namespace: only take read lock in do_reconfigure_mnt() Christian Brauner
2020-10-29 0:32 ` [PATCH 03/34] fs: add mount_setattr() Christian Brauner
2020-11-01 14:42 ` Christoph Hellwig
2020-11-02 13:34 ` Christian Brauner
2020-10-29 0:32 ` [PATCH 04/34] tests: add mount_setattr() selftests Christian Brauner
2020-10-29 0:32 ` [PATCH 05/34] fs: introduce MOUNT_ATTR_IDMAP Christian Brauner
2020-11-01 14:45 ` Christoph Hellwig
2020-11-02 13:29 ` Christian Brauner
2020-10-29 0:32 ` [PATCH 06/34] fs: add id translation helpers Christian Brauner
2020-11-01 14:46 ` Christoph Hellwig
2020-11-02 13:25 ` Christian Brauner
2020-10-29 0:32 ` [PATCH 07/34] capability: handle idmapped mounts Christian Brauner
2020-11-01 14:48 ` Christoph Hellwig
2020-11-02 13:23 ` Christian Brauner
2020-10-29 0:32 ` [PATCH 08/34] namei: add idmapped mount aware permission helpers Christian Brauner
2020-10-29 0:32 ` [PATCH 09/34] inode: add idmapped mount aware init and " Christian Brauner
2020-10-29 0:32 ` [PATCH 10/34] attr: handle idmapped mounts Christian Brauner
2020-10-29 0:32 ` [PATCH 11/34] acl: " Christian Brauner
2020-10-29 0:32 ` [PATCH 12/34] xattr: " Christian Brauner
2020-10-29 0:32 ` [PATCH 13/34] selftests: add idmapped mounts xattr selftest Christian Brauner
2020-10-29 0:32 ` [PATCH 14/34] commoncap: handle idmapped mounts Christian Brauner
2020-10-29 0:32 ` [PATCH 15/34] stat: add mapped_generic_fillattr() Christian Brauner
2020-10-29 0:32 ` [PATCH 16/34] namei: handle idmapped mounts in may_*() helpers Christian Brauner
2020-10-29 0:32 ` [PATCH 17/34] namei: introduce struct renamedata Christian Brauner
2020-10-29 0:32 ` [PATCH 18/34] namei: prepare for idmapped mounts Christian Brauner
2020-10-29 0:32 ` [PATCH 19/34] namei: add lookup helpers with idmapped mounts aware permission checking Christian Brauner
2020-10-29 0:32 ` [PATCH 20/34] open: handle idmapped mounts in do_truncate() Christian Brauner
2020-10-29 0:32 ` [PATCH 21/34] open: handle idmapped mounts Christian Brauner
2020-10-29 0:32 ` [PATCH 22/34] af_unix: " Christian Brauner
2020-10-29 0:32 ` [PATCH 23/34] utimes: " Christian Brauner
2020-10-29 0:32 ` [PATCH 24/34] would_dump: " Christian Brauner
2020-10-29 0:32 ` [PATCH 25/34] exec: " Christian Brauner
2020-10-29 0:32 ` [PATCH 26/34] fs: add helpers for idmap mounts Christian Brauner
2020-10-29 0:32 ` [PATCH 27/34] apparmor: handle idmapped mounts Christian Brauner
2020-10-29 0:32 ` [PATCH 28/34] audit: " Christian Brauner
2020-10-29 0:32 ` [PATCH 29/34] ima: " Christian Brauner
2020-10-29 0:32 ` [PATCH 30/34] ext4: support " Christian Brauner
2020-10-29 0:32 ` [PATCH 31/34] expfs: handle " Christian Brauner
2020-10-29 0:32 ` [PATCH 32/34] overlayfs: handle idmapped lower directories Christian Brauner
2020-10-30 11:10 ` Amir Goldstein
2020-10-30 11:52 ` Christian Brauner
2020-10-29 0:32 ` [PATCH 33/34] overlayfs: handle idmapped merged mounts Christian Brauner
2020-10-30 9:57 ` Amir Goldstein
2020-10-29 0:32 ` Christian Brauner [this message]
2020-10-29 2:27 ` [PATCH 00/34] fs: idmapped mounts Dave Chinner
2020-10-29 16:19 ` Christian Brauner
2020-10-29 7:20 ` Sargun Dhillon
2020-10-29 15:47 ` Eric W. Biederman
2020-10-29 15:51 ` Aleksa Sarai
2020-10-29 16:37 ` Eric W. Biederman
2020-10-30 2:18 ` Serge E. Hallyn
2020-10-30 15:07 ` Seth Forshee
2020-10-30 16:03 ` Serge E. Hallyn
2020-11-03 14:10 ` Alban Crequy
2020-10-29 16:05 ` Lennart Poettering
2020-10-29 16:36 ` Sargun Dhillon
2020-10-29 16:54 ` Eric W. Biederman
[not found] ` <20201029161231.GA108315@cisco>
2020-10-29 16:23 ` Serge E. Hallyn
2020-10-29 16:44 ` Eric W. Biederman
2020-10-29 18:04 ` Stéphane Graber
2020-10-29 21:58 ` Andy Lutomirski
2020-10-30 12:01 ` Christian Brauner
2020-10-30 16:17 ` Serge E. Hallyn
2020-10-31 17:43 ` Andy Lutomirski
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