Changing permissions inside a chroot

Setup:
```
mkdir -p ~/tmp/brw
cd ~/tmp/brw
wget http://cdimage.ubuntu.com/ubuntu-base/releases/trusty/release/ubuntu-base-14.04.5-base-amd64.tar.gz
tar xf ubuntu-base-14.04.5-base-amd64.tar.gz
bwrap --unshare-all --share-net --bind $(pwd) / \
--gid 0 --uid 0 --chdir / --dir /fs --dev /dev --proc /proc \
/bin/bash
```

Then execute the following:

```
chown root:adm ubuntu-base-14.04.5-base-amd64.tar.gz
```

Expected result:
Permissions were changed, no output

Result:
> chown: changing ownership of 'ubuntu-base-14.04.5-base-amd64.tar.gz': Invalid argument

This issue does not occur when using proot, and is specific to bubblewrap. It may not be bubblewrap that's at fault, but that does appear to be the case.