Unable to change file permissions on Ubuntu Bash for Windows 10

Solution 1:

If you're referencing files in the Windows file system, they do not, by default, retain Linux permissions. However, there's a way to enable that. Edit or create (using sudo) /etc/wsl.conf and add the following:

[automount]
options = "metadata"

Shut down all WSL instances and restart an instance, and any chmod changes are now retained.

Solution 2:

The correct way to handle this:

1. Create /etc/wsl.conf with the following:

   [automount]
   enabled  = true
   root     = /mnt/
   options  = "metadata,umask=22,fmask=11"
   

   To understand the meaning of each parameter above, please refer to this article on MSDN

2. Close all WSL terminals and open a new one

3. Restart your machine (as indicated by some comments)

Now you are all set; changing permissions of a file in Windows from /mnt/c/ will be reflected, and mounted, correctly within WSL on startup via the metadata option.

Solution 3:

Is the private key on your Windows filesystem (under /mnt/)? You can't modify the permissions of files on Windows's filesystem using chmod on Bash on Ubuntu on Windows. You'll have to copy the private key to your WSL home directory (~) and do it there.

Some discussion here: https://github.com/Microsoft/WSL/issues/81

Solution 4:

I created an alias that gets loaded in my ~/.bashrc file and allows to unmount/remount the C:/ drive in the /mnt/c/ folder with `"metadata" permissions.

alias win-chmod="cd ~ && sudo umount /mnt/c && sudo mount -t drvfs C: /mnt/c -o metadata && cd -"

This allows me to only enable chmod when I need it, preventing unwanted changes to the mounted file system. It's just a matter of invoking

$ ls -l | grep myfile
-rwxrwxrwx 1 root root          0 Dec 12 16:34 myfile.txt
$ win-chmod
/mnt/c/Users/myself/Documents/myfolder
$ chmod 666 myfile.txt
$ ls -l | grep myfile
-rw-rw-rw- 1 root root          0 Dec 12 16:34 myfile.txt