linux.git/fs/fuse/dir.c, branch v6.12

fs/fuse: convert to use invalid_mnt_idmap

2024-09-23T09:10:26+00:00

We should convert fs/fuse code to use a newly introduced
invalid_mnt_idmap instead of passing a NULL as idmap pointer.

Suggested-by: Christian Brauner 
Signed-off-by: Alexander Mikhalitsyn 
Reviewed-by: Christian Brauner 
Signed-off-by: Miklos Szeredi

fs/fuse: introduce and use fuse_simple_idmap_request() helper

2024-09-23T09:07:55+00:00

Let's convert all existing callers properly.

No functional changes intended.

Suggested-by: Christian Brauner 
Signed-off-by: Alexander Mikhalitsyn 
Reviewed-by: Christian Brauner 
Signed-off-by: Miklos Szeredi

fuse: warn if fuse_access is called when idmapped mounts are allowed

2024-09-04T14:51:11+00:00

It is not possible with the current fuse code, but let's protect ourselves
from regressions in the future.

Signed-off-by: Alexander Mikhalitsyn 
Signed-off-by: Miklos Szeredi

fuse: support idmapped ->rename op

2024-09-04T14:51:11+00:00

RENAME_WHITEOUT is a special case of ->rename
and we need to take idmappings into account there.

Signed-off-by: Alexander Mikhalitsyn 
Signed-off-by: Miklos Szeredi

fuse: support idmapped ->setattr op

2024-09-04T14:51:06+00:00

Need to translate uid and gid in case of chown(2).

Signed-off-by: Alexander Mikhalitsyn 
Reviewed-by: Christian Brauner 
Signed-off-by: Miklos Szeredi

fuse: support idmapped ->permission inode op

2024-09-04T14:49:58+00:00

We only cover the case when "default_permissions" flag
is used. A reason for that is that otherwise all the permission
checks are done in the userspace and we have to deal with
VFS idmapping in the userspace (which is bad), alternatively
we have to provide the userspace with idmapped req->in.h.uid/req->in.h.gid
which is also not align with VFS idmaps philosophy.

Signed-off-by: Alexander Mikhalitsyn 
Reviewed-by: Christian Brauner 
Signed-off-by: Miklos Szeredi

fuse: support idmapped getattr inode op

2024-09-04T14:49:28+00:00

We have to:
- pass an idmapping to the generic_fillattr()
to properly handle UIG/GID mapping for the userspace.
- pass -/- to fuse_fillattr() (analog of generic_fillattr() in fuse).

Difference between these two is that generic_fillattr() takes all the
stat() data from the inode directly, while fuse_fillattr() codepath takes a
fresh data just from the userspace reply on the FUSE_GETATTR request.

In some cases we can just pass &nop_mnt_idmap, because idmapping won't be
used in these codepaths. For example, when 3rd argument of
fuse_do_getattr() is NULL then idmap argument is not used.

Signed-off-by: Alexander Mikhalitsyn 
Reviewed-by: Christian Brauner 
Signed-off-by: Miklos Szeredi

fuse: support idmap for mkdir/mknod/symlink/create/tmpfile

2024-09-04T14:49:22+00:00

We have all the infrastructure in place, we just need
to pass an idmapping here.

Signed-off-by: Alexander Mikhalitsyn 
Reviewed-by: Christian Brauner 
Signed-off-by: Miklos Szeredi

fuse: support idmapped FUSE_EXT_GROUPS

2024-09-04T14:48:22+00:00

We don't need to remap parent_gid, but have to adjust
group membership checks and take idmapping into account.

Signed-off-by: Alexander Mikhalitsyn 
Signed-off-by: Miklos Szeredi

fuse: add an idmap argument to fuse_simple_request

2024-09-04T14:48:22+00:00

If idmap == NULL *and* filesystem daemon declared idmapped mounts
support, then uid/gid values in a fuse header will be -1.

No functional changes intended.

Signed-off-by: Alexander Mikhalitsyn 
Signed-off-by: Miklos Szeredi