diff options
| author |   Tomohiro Misono <misono.tomohiro@jp.fujitsu.com> | 2018-05-21 10:09:44 +0900 |
|---|---|---|
| committer |   David Sterba <dsterba@suse.com> | 2018-05-31 11:35:24 +0200 |
| commit | 23d0b79dfaed2305b500b0215b0421701ada6b1a (patch) | |
| tree | eeb57dfec279e2d7c737e354d6929145745ae5e5 /include | |
| parent | btrfs: Add unprivileged ioctl which returns subvolume's ROOT_REF (diff) | |
| download | wireguard-linux-23d0b79dfaed2305b500b0215b0421701ada6b1a.tar.xz wireguard-linux-23d0b79dfaed2305b500b0215b0421701ada6b1a.zip | |
btrfs: Add unprivileged version of ino_lookup ioctl
Add unprivileged version of ino_lookup ioctl BTRFS_IOC_INO_LOOKUP_USER
to allow normal users to call "btrfs subvolume list/show" etc. in
combination with BTRFS_IOC_GET_SUBVOL_INFO/BTRFS_IOC_GET_SUBVOL_ROOTREF.
This can be used like BTRFS_IOC_INO_LOOKUP but the argument is
different. This is because it always searches the fs/file tree
correspoinding to the fd with which this ioctl is called and also
returns the name of bottom subvolume.
The main differences from original ino_lookup ioctl are:
1. Read + Exec permission will be checked using inode_permission()
during path construction. -EACCES will be returned in case
of failure.
2. Path construction will be stopped at the inode number which
corresponds to the fd with which this ioctl is called. If
constructed path does not exist under fd's inode, -EACCES
will be returned.
3. The name of bottom subvolume is also searched and filled.
Note that the maximum length of path is shorter 256 (BTRFS_VOL_NAME_MAX+1)
bytes than ino_lookup ioctl because of space of subvolume's name.
Reviewed-by: Gu Jinxiang <gujx@cn.fujitsu.com>
Reviewed-by: Qu Wenruo <wqu@suse.com>
Tested-by: Gu Jinxiang <gujx@cn.fujitsu.com>
Signed-off-by: Tomohiro Misono <misono.tomohiro@jp.fujitsu.com>
[ style fixes ]
Signed-off-by: David Sterba <dsterba@suse.com>
Diffstat (limited to 'include')
| -rw-r--r-- | include/uapi/linux/btrfs.h | 17 |
1 files changed, 17 insertions, 0 deletions
diff --git a/include/uapi/linux/btrfs.h b/include/uapi/linux/btrfs.h index f90d10478235..5ca1d21fc4a7 100644 --- a/include/uapi/linux/btrfs.h +++ b/include/uapi/linux/btrfs.h @@ -422,6 +422,21 @@ struct btrfs_ioctl_ino_lookup_args { char name[BTRFS_INO_LOOKUP_PATH_MAX]; }; +#define BTRFS_INO_LOOKUP_USER_PATH_MAX (4080 - BTRFS_VOL_NAME_MAX - 1) +struct btrfs_ioctl_ino_lookup_user_args { + /* in, inode number containing the subvolume of 'subvolid' */ + __u64 dirid; + /* in */ + __u64 treeid; + /* out, name of the subvolume of 'treeid' */ + char name[BTRFS_VOL_NAME_MAX + 1]; + /* + * out, constructed path from the directory with which the ioctl is + * called to dirid + */ + char path[BTRFS_INO_LOOKUP_USER_PATH_MAX]; +}; + /* Search criteria for the btrfs SEARCH ioctl family. */ struct btrfs_ioctl_search_key { /* @@ -923,5 +938,7 @@ enum btrfs_err_code { struct btrfs_ioctl_get_subvol_info_args) #define BTRFS_IOC_GET_SUBVOL_ROOTREF _IOWR(BTRFS_IOCTL_MAGIC, 61, \ struct btrfs_ioctl_get_subvol_rootref_args) +#define BTRFS_IOC_INO_LOOKUP_USER _IOWR(BTRFS_IOCTL_MAGIC, 62, \ + struct btrfs_ioctl_ino_lookup_user_args) #endif /* _UAPI_LINUX_BTRFS_H */ |