umask seems to set execute bit for all files/directories

[icassassin]

Tested on both unionfs-fuse 1.0 (as installed from the Ubuntu 22.04 repos) and 3.4 (built from source).

I'm merging a few directories together and I'd like it to be readonly, and I'd like the file system to know that everything is read-only. I set umask=0222 and I expect that the write bit will be disabled for everything, and that's true, but it also seems to set the execute bit for every file as well.

For example, one of the files I have in these directories has rw-r--r-- permissions. If is merge this with other directories w/ unionfs, without passing a umask, the permissions for that file are rw-r--r--. If I pass umask=0222, then the permissions for that file are r-xr-xr-x.

If I set umask=0333, execute bits are not set but, as expected, this also applies to directories (I assume it applies to the files inside).

Is this expected?