chown misinterprets "." as group separator

[Matthew Slowe]

Afternoon,

A few months ago I raised a bug against the "chown" applet https://bugs.busybox.net/show_bug.cgi?id=16039 as I was hitting a problem with users with a "." in their username.

In uidgid_get.c there is a parse_chown_usergroup_or_die() function which continues to implement a very old BSD(?) notation of user.group as well as user:group -- the code assumes that the first "." is a separater.

I don't know what else calls it but, for the chown applet, the implementation precludes support of users with "."s in (such as "test.test") when invoked with "chown test.test file":

     # chown test.test /tmp/test
     chown: unknown user/group test:test

https://github.com/mirror/busybox/blame/master/libpwdgrp/uidgid_get.c#L96

There is no reference to this interpretation in the code comment of the usage string:

    Usage: chown [-RhLHPcvf]... USER[:[GRP]] FILE...

Given that this notation appears to have been deprecated back in 2001, is now the time to remove this?

There's a potential patch attached to the bug report.

-- 
Matthew