diff options
| author | Alexander Mikhalitsyn <aleksandr.mikhalitsyn@canonical.com> | 2024-09-03 17:16:25 +0200 |
|---|---|---|
| committer | Miklos Szeredi <mszeredi@redhat.com> | 2024-09-04 16:51:11 +0200 |
| commit | 16e1503eaf329129170e4e7a078aee17686967a5 (patch) | |
| tree | c6b23f7ab6d60204a18e5a109fa946a72f9587cf /fs/fuse/inode.c | |
| parent | 6d14b18596ca69719cfe1af87dbf3c5e763d29b5 (diff) | |
fuse: allow idmapped mounts
Now we have everything in place and we can allow idmapped mounts
by setting the FS_ALLOW_IDMAP flag. Notice that real availability
of idmapped mounts will depend on the fuse daemon. Fuse daemon
have to set FUSE_ALLOW_IDMAP flag in the FUSE_INIT reply.
To discuss:
- we enable idmapped mounts support only if "default_permissions" mode is
enabled, because otherwise we would need to deal with UID/GID mappings in
the userspace side OR provide the userspace with idmapped
req->in.h.uid/req->in.h.gid values which is not something that we probably
want to. Idmapped mounts philosophy is not about faking caller uid/gid.
Some extra links and examples:
- libfuse support
https://github.com/mihalicyn/libfuse/commits/idmap_support
- fuse-overlayfs support:
https://github.com/mihalicyn/fuse-overlayfs/commits/idmap_support
- cephfs-fuse conversion example
https://github.com/mihalicyn/ceph/commits/fuse_idmap
- glusterfs conversion example
https://github.com/mihalicyn/glusterfs/commits/fuse_idmap
Signed-off-by: Alexander Mikhalitsyn <aleksandr.mikhalitsyn@canonical.com>
Reviewed-by: Christian Brauner <brauner@kernel.org>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
Diffstat (limited to 'fs/fuse/inode.c')
| -rw-r--r-- | fs/fuse/inode.c | 12 |
1 files changed, 9 insertions, 3 deletions
diff --git a/fs/fuse/inode.c b/fs/fuse/inode.c index b08bc6081612..d7edb3fb829f 100644 --- a/fs/fuse/inode.c +++ b/fs/fuse/inode.c @@ -1348,6 +1348,12 @@ static void process_init_reply(struct fuse_mount *fm, struct fuse_args *args, } if (flags & FUSE_NO_EXPORT_SUPPORT) fm->sb->s_export_op = &fuse_export_fid_operations; + if (flags & FUSE_ALLOW_IDMAP) { + if (fc->default_permissions) + fm->sb->s_iflags &= ~SB_I_NOIDMAP; + else + ok = false; + } } else { ra_pages = fc->max_read / PAGE_SIZE; fc->no_lock = 1; @@ -1395,7 +1401,7 @@ void fuse_send_init(struct fuse_mount *fm) FUSE_HANDLE_KILLPRIV_V2 | FUSE_SETXATTR_EXT | FUSE_INIT_EXT | FUSE_SECURITY_CTX | FUSE_CREATE_SUPP_GROUP | FUSE_HAS_EXPIRE_ONLY | FUSE_DIRECT_IO_ALLOW_MMAP | - FUSE_NO_EXPORT_SUPPORT | FUSE_HAS_RESEND; + FUSE_NO_EXPORT_SUPPORT | FUSE_HAS_RESEND | FUSE_ALLOW_IDMAP; #ifdef CONFIG_FUSE_DAX if (fm->fc->dax) flags |= FUSE_MAP_ALIGNMENT; @@ -1985,7 +1991,7 @@ static void fuse_kill_sb_anon(struct super_block *sb) static struct file_system_type fuse_fs_type = { .owner = THIS_MODULE, .name = "fuse", - .fs_flags = FS_HAS_SUBTYPE | FS_USERNS_MOUNT, + .fs_flags = FS_HAS_SUBTYPE | FS_USERNS_MOUNT | FS_ALLOW_IDMAP, .init_fs_context = fuse_init_fs_context, .parameters = fuse_fs_parameters, .kill_sb = fuse_kill_sb_anon, @@ -2006,7 +2012,7 @@ static struct file_system_type fuseblk_fs_type = { .init_fs_context = fuse_init_fs_context, .parameters = fuse_fs_parameters, .kill_sb = fuse_kill_sb_blk, - .fs_flags = FS_REQUIRES_DEV | FS_HAS_SUBTYPE, + .fs_flags = FS_REQUIRES_DEV | FS_HAS_SUBTYPE | FS_ALLOW_IDMAP, }; MODULE_ALIAS_FS("fuseblk"); |