mirror of
https://mirrors.bfsu.edu.cn/git/linux.git
synced 2024-11-24 12:44:11 +08:00
ext4: support idmapped mounts
Enable idmapped mounts for ext4. All dedicated helpers we need for this
exist. So this basically just means we're passing down the
user_namespace argument from the VFS methods to the relevant helpers.
Let's create simple example where we idmap an ext4 filesystem:
root@f2-vm:~# truncate -s 5G ext4.img
root@f2-vm:~# mkfs.ext4 ./ext4.img
mke2fs 1.45.5 (07-Jan-2020)
Discarding device blocks: done
Creating filesystem with 1310720 4k blocks and 327680 inodes
Filesystem UUID: 3fd91794-c6ca-4b0f-9964-289a000919cf
Superblock backups stored on blocks:
32768, 98304, 163840, 229376, 294912, 819200, 884736
Allocating group tables: done
Writing inode tables: done
Creating journal (16384 blocks): done
Writing superblocks and filesystem accounting information: done
root@f2-vm:~# losetup -f --show ./ext4.img
/dev/loop0
root@f2-vm:~# mount /dev/loop0 /mnt
root@f2-vm:~# ls -al /mnt/
total 24
drwxr-xr-x 3 root root 4096 Oct 28 13:34 .
drwxr-xr-x 30 root root 4096 Oct 28 13:22 ..
drwx------ 2 root root 16384 Oct 28 13:34 lost+found
# Let's create an idmapped mount at /idmapped1 where we map uid and gid
# 0 to uid and gid 1000
root@f2-vm:/# ./mount-idmapped --map-mount b:0:1000:1 /mnt/ /idmapped1/
root@f2-vm:/# ls -al /idmapped1/
total 24
drwxr-xr-x 3 ubuntu ubuntu 4096 Oct 28 13:34 .
drwxr-xr-x 30 root root 4096 Oct 28 13:22 ..
drwx------ 2 ubuntu ubuntu 16384 Oct 28 13:34 lost+found
# Let's create an idmapped mount at /idmapped2 where we map uid and gid
# 0 to uid and gid 2000
root@f2-vm:/# ./mount-idmapped --map-mount b:0:2000:1 /mnt/ /idmapped2/
root@f2-vm:/# ls -al /idmapped2/
total 24
drwxr-xr-x 3 2000 2000 4096 Oct 28 13:34 .
drwxr-xr-x 31 root root 4096 Oct 28 13:39 ..
drwx------ 2 2000 2000 16384 Oct 28 13:34 lost+found
Let's create another example where we idmap the rootfs filesystem
without a mapping for uid 0 and gid 0:
# Create an idmapped mount of for a full POSIX range of rootfs under
# /mnt but without a mapping for uid 0 to reduce attack surface
root@f2-vm:/# ./mount-idmapped --map-mount b:1:1:65536 / /mnt/
# Since we don't have a mapping for uid and gid 0 all files owned by
# uid and gid 0 should show up as uid and gid 65534:
root@f2-vm:/# ls -al /mnt/
total 664
drwxr-xr-x 31 nobody nogroup 4096 Oct 28 13:39 .
drwxr-xr-x 31 root root 4096 Oct 28 13:39 ..
lrwxrwxrwx 1 nobody nogroup 7 Aug 25 07:44 bin -> usr/bin
drwxr-xr-x 4 nobody nogroup 4096 Oct 28 13:17 boot
drwxr-xr-x 2 nobody nogroup 4096 Aug 25 07:48 dev
drwxr-xr-x 81 nobody nogroup 4096 Oct 28 04:00 etc
drwxr-xr-x 4 nobody nogroup 4096 Oct 28 04:00 home
lrwxrwxrwx 1 nobody nogroup 7 Aug 25 07:44 lib -> usr/lib
lrwxrwxrwx 1 nobody nogroup 9 Aug 25 07:44 lib32 -> usr/lib32
lrwxrwxrwx 1 nobody nogroup 9 Aug 25 07:44 lib64 -> usr/lib64
lrwxrwxrwx 1 nobody nogroup 10 Aug 25 07:44 libx32 -> usr/libx32
drwx------ 2 nobody nogroup 16384 Aug 25 07:47 lost+found
drwxr-xr-x 2 nobody nogroup 4096 Aug 25 07:44 media
drwxr-xr-x 31 nobody nogroup 4096 Oct 28 13:39 mnt
drwxr-xr-x 2 nobody nogroup 4096 Aug 25 07:44 opt
drwxr-xr-x 2 nobody nogroup 4096 Apr 15 2020 proc
drwx--x--x 6 nobody nogroup 4096 Oct 28 13:34 root
drwxr-xr-x 2 nobody nogroup 4096 Aug 25 07:46 run
lrwxrwxrwx 1 nobody nogroup 8 Aug 25 07:44 sbin -> usr/sbin
drwxr-xr-x 2 nobody nogroup 4096 Aug 25 07:44 srv
drwxr-xr-x 2 nobody nogroup 4096 Apr 15 2020 sys
drwxrwxrwt 10 nobody nogroup 4096 Oct 28 13:19 tmp
drwxr-xr-x 14 nobody nogroup 4096 Oct 20 13:00 usr
drwxr-xr-x 12 nobody nogroup 4096 Aug 25 07:45 var
# Since we do have a mapping for uid and gid 1000 all files owned by
# uid and gid 1000 should simply show up as uid and gid 1000:
root@f2-vm:/# ls -al /mnt/home/ubuntu/
total 40
drwxr-xr-x 3 ubuntu ubuntu 4096 Oct 28 00:43 .
drwxr-xr-x 4 nobody nogroup 4096 Oct 28 04:00 ..
-rw------- 1 ubuntu ubuntu 2936 Oct 28 12:26 .bash_history
-rw-r--r-- 1 ubuntu ubuntu 220 Feb 25 2020 .bash_logout
-rw-r--r-- 1 ubuntu ubuntu 3771 Feb 25 2020 .bashrc
-rw-r--r-- 1 ubuntu ubuntu 807 Feb 25 2020 .profile
-rw-r--r-- 1 ubuntu ubuntu 0 Oct 16 16:11 .sudo_as_admin_successful
-rw------- 1 ubuntu ubuntu 1144 Oct 28 00:43 .viminfo
Link: https://lore.kernel.org/r/20210121131959.646623-39-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-ext4@vger.kernel.org
Cc: linux-fsdevel@vger.kernel.org
Signed-off-by: Christian Brauner <christian.brauner@ubuntu.com>
This commit is contained in:
Christian Brauner
parent
4b78993681
commit
14f3db5542
@ -246,8 +246,7 @@ retry:
|
||||
ext4_fc_start_update(inode);
|
||||
|
||||
if ((type == ACL_TYPE_ACCESS) && acl) {
|
||||
error = posix_acl_update_mode(&init_user_ns, inode, &mode,
|
||||
&acl);
|
||||
error = posix_acl_update_mode(mnt_userns, inode, &mode, &acl);
|
||||
if (error)
|
||||
goto out_stop;
|
||||
if (mode != inode->i_mode)
|
||||
|
||||
@ -2755,18 +2755,19 @@ extern int ext4fs_dirhash(const struct inode *dir, const char *name, int len,
|
||||
|
||||
/* ialloc.c */
|
||||
extern int ext4_mark_inode_used(struct super_block *sb, int ino);
|
||||
extern struct inode *__ext4_new_inode(handle_t *, struct inode *, umode_t,
|
||||
extern struct inode *__ext4_new_inode(struct user_namespace *, handle_t *,
|
||||
struct inode *, umode_t,
|
||||
const struct qstr *qstr, __u32 goal,
|
||||
uid_t *owner, __u32 i_flags,
|
||||
int handle_type, unsigned int line_no,
|
||||
int nblocks);
|
||||
|
||||
#define ext4_new_inode(handle, dir, mode, qstr, goal, owner, i_flags) \
|
||||
__ext4_new_inode((handle), (dir), (mode), (qstr), (goal), (owner), \
|
||||
i_flags, 0, 0, 0)
|
||||
#define ext4_new_inode_start_handle(dir, mode, qstr, goal, owner, \
|
||||
#define ext4_new_inode(handle, dir, mode, qstr, goal, owner, i_flags) \
|
||||
__ext4_new_inode(&init_user_ns, (handle), (dir), (mode), (qstr), \
|
||||
(goal), (owner), i_flags, 0, 0, 0)
|
||||
#define ext4_new_inode_start_handle(mnt_userns, dir, mode, qstr, goal, owner, \
|
||||
type, nblocks) \
|
||||
__ext4_new_inode(NULL, (dir), (mode), (qstr), (goal), (owner), \
|
||||
__ext4_new_inode((mnt_userns), NULL, (dir), (mode), (qstr), (goal), (owner), \
|
||||
0, (type), __LINE__, (nblocks))
|
||||
|
||||
|
||||
|
||||
@ -919,7 +919,8 @@ static int ext4_xattr_credits_for_new_inode(struct inode *dir, mode_t mode,
|
||||
* For other inodes, search forward from the parent directory's block
|
||||
* group to find a free inode.
|
||||
*/
|
||||
struct inode *__ext4_new_inode(handle_t *handle, struct inode *dir,
|
||||
struct inode *__ext4_new_inode(struct user_namespace *mnt_userns,
|
||||
handle_t *handle, struct inode *dir,
|
||||
umode_t mode, const struct qstr *qstr,
|
||||
__u32 goal, uid_t *owner, __u32 i_flags,
|
||||
int handle_type, unsigned int line_no,
|
||||
@ -969,10 +970,10 @@ struct inode *__ext4_new_inode(handle_t *handle, struct inode *dir,
|
||||
i_gid_write(inode, owner[1]);
|
||||
} else if (test_opt(sb, GRPID)) {
|
||||
inode->i_mode = mode;
|
||||
inode->i_uid = current_fsuid();
|
||||
inode->i_uid = fsuid_into_mnt(mnt_userns);
|
||||
inode->i_gid = dir->i_gid;
|
||||
} else
|
||||
inode_init_owner(&init_user_ns, inode, dir, mode);
|
||||
inode_init_owner(mnt_userns, inode, dir, mode);
|
||||
|
||||
if (ext4_has_feature_project(sb) &&
|
||||
ext4_test_inode_flag(dir, EXT4_INODE_PROJINHERIT))
|
||||
|
||||
@ -20,6 +20,7 @@
|
||||
*/
|
||||
|
||||
#include <linux/fs.h>
|
||||
#include <linux/mount.h>
|
||||
#include <linux/time.h>
|
||||
#include <linux/highuid.h>
|
||||
#include <linux/pagemap.h>
|
||||
@ -5338,7 +5339,7 @@ int ext4_setattr(struct user_namespace *mnt_userns, struct dentry *dentry,
|
||||
ATTR_GID | ATTR_TIMES_SET))))
|
||||
return -EPERM;
|
||||
|
||||
error = setattr_prepare(&init_user_ns, dentry, attr);
|
||||
error = setattr_prepare(mnt_userns, dentry, attr);
|
||||
if (error)
|
||||
return error;
|
||||
|
||||
@ -5513,7 +5514,7 @@ out_mmap_sem:
|
||||
}
|
||||
|
||||
if (!error) {
|
||||
setattr_copy(&init_user_ns, inode, attr);
|
||||
setattr_copy(mnt_userns, inode, attr);
|
||||
mark_inode_dirty(inode);
|
||||
}
|
||||
|
||||
@ -5525,7 +5526,7 @@ out_mmap_sem:
|
||||
ext4_orphan_del(NULL, inode);
|
||||
|
||||
if (!error && (ia_valid & ATTR_MODE))
|
||||
rc = posix_acl_chmod(&init_user_ns, inode, inode->i_mode);
|
||||
rc = posix_acl_chmod(mnt_userns, inode, inode->i_mode);
|
||||
|
||||
err_out:
|
||||
if (error)
|
||||
@ -5572,7 +5573,7 @@ int ext4_getattr(struct user_namespace *mnt_userns, const struct path *path,
|
||||
STATX_ATTR_NODUMP |
|
||||
STATX_ATTR_VERITY);
|
||||
|
||||
generic_fillattr(&init_user_ns, inode, stat);
|
||||
generic_fillattr(mnt_userns, inode, stat);
|
||||
return 0;
|
||||
}
|
||||
|
||||
@ -5583,7 +5584,7 @@ int ext4_file_getattr(struct user_namespace *mnt_userns,
|
||||
struct inode *inode = d_inode(path->dentry);
|
||||
u64 delalloc_blocks;
|
||||
|
||||
ext4_getattr(&init_user_ns, path, stat, request_mask, query_flags);
|
||||
ext4_getattr(mnt_userns, path, stat, request_mask, query_flags);
|
||||
|
||||
/*
|
||||
* If there is inline data in the inode, the inode will normally not
|
||||
|
||||
@ -107,10 +107,12 @@ void ext4_reset_inode_seed(struct inode *inode)
|
||||
* important fields of the inodes.
|
||||
*
|
||||
* @sb: the super block of the filesystem
|
||||
* @mnt_userns: user namespace of the mount the inode was found from
|
||||
* @inode: the inode to swap with EXT4_BOOT_LOADER_INO
|
||||
*
|
||||
*/
|
||||
static long swap_inode_boot_loader(struct super_block *sb,
|
||||
struct user_namespace *mnt_userns,
|
||||
struct inode *inode)
|
||||
{
|
||||
handle_t *handle;
|
||||
@ -139,7 +141,7 @@ static long swap_inode_boot_loader(struct super_block *sb,
|
||||
}
|
||||
|
||||
if (IS_RDONLY(inode) || IS_APPEND(inode) || IS_IMMUTABLE(inode) ||
|
||||
!inode_owner_or_capable(&init_user_ns, inode) ||
|
||||
!inode_owner_or_capable(mnt_userns, inode) ||
|
||||
!capable(CAP_SYS_ADMIN)) {
|
||||
err = -EPERM;
|
||||
goto journal_err_out;
|
||||
@ -815,6 +817,7 @@ static long __ext4_ioctl(struct file *filp, unsigned int cmd, unsigned long arg)
|
||||
struct inode *inode = file_inode(filp);
|
||||
struct super_block *sb = inode->i_sb;
|
||||
struct ext4_inode_info *ei = EXT4_I(inode);
|
||||
struct user_namespace *mnt_userns = file_mnt_user_ns(filp);
|
||||
unsigned int flags;
|
||||
|
||||
ext4_debug("cmd = %u, arg = %lu\n", cmd, arg);
|
||||
@ -830,7 +833,7 @@ static long __ext4_ioctl(struct file *filp, unsigned int cmd, unsigned long arg)
|
||||
case FS_IOC_SETFLAGS: {
|
||||
int err;
|
||||
|
||||
if (!inode_owner_or_capable(&init_user_ns, inode))
|
||||
if (!inode_owner_or_capable(mnt_userns, inode))
|
||||
return -EACCES;
|
||||
|
||||
if (get_user(flags, (int __user *) arg))
|
||||
@ -872,7 +875,7 @@ static long __ext4_ioctl(struct file *filp, unsigned int cmd, unsigned long arg)
|
||||
__u32 generation;
|
||||
int err;
|
||||
|
||||
if (!inode_owner_or_capable(&init_user_ns, inode))
|
||||
if (!inode_owner_or_capable(mnt_userns, inode))
|
||||
return -EPERM;
|
||||
|
||||
if (ext4_has_metadata_csum(inode->i_sb)) {
|
||||
@ -1011,7 +1014,7 @@ mext_out:
|
||||
case EXT4_IOC_MIGRATE:
|
||||
{
|
||||
int err;
|
||||
if (!inode_owner_or_capable(&init_user_ns, inode))
|
||||
if (!inode_owner_or_capable(mnt_userns, inode))
|
||||
return -EACCES;
|
||||
|
||||
err = mnt_want_write_file(filp);
|
||||
@ -1033,7 +1036,7 @@ mext_out:
|
||||
case EXT4_IOC_ALLOC_DA_BLKS:
|
||||
{
|
||||
int err;
|
||||
if (!inode_owner_or_capable(&init_user_ns, inode))
|
||||
if (!inode_owner_or_capable(mnt_userns, inode))
|
||||
return -EACCES;
|
||||
|
||||
err = mnt_want_write_file(filp);
|
||||
@ -1052,7 +1055,7 @@ mext_out:
|
||||
err = mnt_want_write_file(filp);
|
||||
if (err)
|
||||
return err;
|
||||
err = swap_inode_boot_loader(sb, inode);
|
||||
err = swap_inode_boot_loader(sb, mnt_userns, inode);
|
||||
mnt_drop_write_file(filp);
|
||||
return err;
|
||||
}
|
||||
@ -1218,7 +1221,7 @@ resizefs_out:
|
||||
|
||||
case EXT4_IOC_CLEAR_ES_CACHE:
|
||||
{
|
||||
if (!inode_owner_or_capable(&init_user_ns, inode))
|
||||
if (!inode_owner_or_capable(mnt_userns, inode))
|
||||
return -EACCES;
|
||||
ext4_clear_inode_es(inode);
|
||||
return 0;
|
||||
@ -1264,7 +1267,7 @@ resizefs_out:
|
||||
return -EFAULT;
|
||||
|
||||
/* Make sure caller has proper permission */
|
||||
if (!inode_owner_or_capable(&init_user_ns, inode))
|
||||
if (!inode_owner_or_capable(mnt_userns, inode))
|
||||
return -EACCES;
|
||||
|
||||
if (fa.fsx_xflags & ~EXT4_SUPPORTED_FS_XFLAGS)
|
||||
|
||||
@ -2610,8 +2610,8 @@ static int ext4_create(struct user_namespace *mnt_userns, struct inode *dir,
|
||||
credits = (EXT4_DATA_TRANS_BLOCKS(dir->i_sb) +
|
||||
EXT4_INDEX_EXTRA_TRANS_BLOCKS + 3);
|
||||
retry:
|
||||
inode = ext4_new_inode_start_handle(dir, mode, &dentry->d_name, 0,
|
||||
NULL, EXT4_HT_DIR, credits);
|
||||
inode = ext4_new_inode_start_handle(mnt_userns, dir, mode, &dentry->d_name,
|
||||
0, NULL, EXT4_HT_DIR, credits);
|
||||
handle = ext4_journal_current_handle();
|
||||
err = PTR_ERR(inode);
|
||||
if (!IS_ERR(inode)) {
|
||||
@ -2645,8 +2645,8 @@ static int ext4_mknod(struct user_namespace *mnt_userns, struct inode *dir,
|
||||
credits = (EXT4_DATA_TRANS_BLOCKS(dir->i_sb) +
|
||||
EXT4_INDEX_EXTRA_TRANS_BLOCKS + 3);
|
||||
retry:
|
||||
inode = ext4_new_inode_start_handle(dir, mode, &dentry->d_name, 0,
|
||||
NULL, EXT4_HT_DIR, credits);
|
||||
inode = ext4_new_inode_start_handle(mnt_userns, dir, mode, &dentry->d_name,
|
||||
0, NULL, EXT4_HT_DIR, credits);
|
||||
handle = ext4_journal_current_handle();
|
||||
err = PTR_ERR(inode);
|
||||
if (!IS_ERR(inode)) {
|
||||
@ -2677,7 +2677,7 @@ static int ext4_tmpfile(struct user_namespace *mnt_userns, struct inode *dir,
|
||||
return err;
|
||||
|
||||
retry:
|
||||
inode = ext4_new_inode_start_handle(dir, mode,
|
||||
inode = ext4_new_inode_start_handle(mnt_userns, dir, mode,
|
||||
NULL, 0, NULL,
|
||||
EXT4_HT_DIR,
|
||||
EXT4_MAXQUOTAS_INIT_BLOCKS(dir->i_sb) +
|
||||
@ -2792,7 +2792,7 @@ static int ext4_mkdir(struct user_namespace *mnt_userns, struct inode *dir,
|
||||
credits = (EXT4_DATA_TRANS_BLOCKS(dir->i_sb) +
|
||||
EXT4_INDEX_EXTRA_TRANS_BLOCKS + 3);
|
||||
retry:
|
||||
inode = ext4_new_inode_start_handle(dir, S_IFDIR | mode,
|
||||
inode = ext4_new_inode_start_handle(mnt_userns, dir, S_IFDIR | mode,
|
||||
&dentry->d_name,
|
||||
0, NULL, EXT4_HT_DIR, credits);
|
||||
handle = ext4_journal_current_handle();
|
||||
@ -3335,7 +3335,7 @@ static int ext4_symlink(struct user_namespace *mnt_userns, struct inode *dir,
|
||||
EXT4_INDEX_EXTRA_TRANS_BLOCKS + 3;
|
||||
}
|
||||
|
||||
inode = ext4_new_inode_start_handle(dir, S_IFLNK|S_IRWXUGO,
|
||||
inode = ext4_new_inode_start_handle(mnt_userns, dir, S_IFLNK|S_IRWXUGO,
|
||||
&dentry->d_name, 0, NULL,
|
||||
EXT4_HT_DIR, credits);
|
||||
handle = ext4_journal_current_handle();
|
||||
@ -3664,7 +3664,8 @@ static void ext4_update_dir_count(handle_t *handle, struct ext4_renament *ent)
|
||||
}
|
||||
}
|
||||
|
||||
static struct inode *ext4_whiteout_for_rename(struct ext4_renament *ent,
|
||||
static struct inode *ext4_whiteout_for_rename(struct user_namespace *mnt_userns,
|
||||
struct ext4_renament *ent,
|
||||
int credits, handle_t **h)
|
||||
{
|
||||
struct inode *wh;
|
||||
@ -3678,7 +3679,8 @@ static struct inode *ext4_whiteout_for_rename(struct ext4_renament *ent,
|
||||
credits += (EXT4_MAXQUOTAS_TRANS_BLOCKS(ent->dir->i_sb) +
|
||||
EXT4_XATTR_TRANS_BLOCKS + 4);
|
||||
retry:
|
||||
wh = ext4_new_inode_start_handle(ent->dir, S_IFCHR | WHITEOUT_MODE,
|
||||
wh = ext4_new_inode_start_handle(mnt_userns, ent->dir,
|
||||
S_IFCHR | WHITEOUT_MODE,
|
||||
&ent->dentry->d_name, 0, NULL,
|
||||
EXT4_HT_DIR, credits);
|
||||
|
||||
@ -3705,9 +3707,9 @@ retry:
|
||||
* while new_{dentry,inode) refers to the destination dentry/inode
|
||||
* This comes from rename(const char *oldpath, const char *newpath)
|
||||
*/
|
||||
static int ext4_rename(struct inode *old_dir, struct dentry *old_dentry,
|
||||
struct inode *new_dir, struct dentry *new_dentry,
|
||||
unsigned int flags)
|
||||
static int ext4_rename(struct user_namespace *mnt_userns, struct inode *old_dir,
|
||||
struct dentry *old_dentry, struct inode *new_dir,
|
||||
struct dentry *new_dentry, unsigned int flags)
|
||||
{
|
||||
handle_t *handle = NULL;
|
||||
struct ext4_renament old = {
|
||||
@ -3791,7 +3793,7 @@ static int ext4_rename(struct inode *old_dir, struct dentry *old_dentry,
|
||||
goto end_rename;
|
||||
}
|
||||
} else {
|
||||
whiteout = ext4_whiteout_for_rename(&old, credits, &handle);
|
||||
whiteout = ext4_whiteout_for_rename(mnt_userns, &old, credits, &handle);
|
||||
if (IS_ERR(whiteout)) {
|
||||
retval = PTR_ERR(whiteout);
|
||||
whiteout = NULL;
|
||||
@ -4110,7 +4112,7 @@ static int ext4_rename2(struct user_namespace *mnt_userns,
|
||||
new_dir, new_dentry);
|
||||
}
|
||||
|
||||
return ext4_rename(old_dir, old_dentry, new_dir, new_dentry, flags);
|
||||
return ext4_rename(mnt_userns, old_dir, old_dentry, new_dir, new_dentry, flags);
|
||||
}
|
||||
|
||||
/*
|
||||
|
||||
@ -6654,7 +6654,7 @@ static struct file_system_type ext4_fs_type = {
|
||||
.name = "ext4",
|
||||
.mount = ext4_mount,
|
||||
.kill_sb = kill_block_super,
|
||||
.fs_flags = FS_REQUIRES_DEV,
|
||||
.fs_flags = FS_REQUIRES_DEV | FS_ALLOW_IDMAP,
|
||||
};
|
||||
MODULE_ALIAS_FS("ext4");
|
||||
|
||||
|
||||
Loading…
Reference in New Issue
Block a user