Unfortunate results from fake-super

[Dave Gordon]

On 05/02/18 05:53, Wayne Davison wrote:
> On Sat, Feb 3, 2018 at 5:20 AM, Dave Gordon via rsync
> <rsync at lists.samba.org <mailto:rsync at lists.samba.org>> wrote:
> 
>     [...fake-super symlink saved as a file...]
> 
>     This results in the copy being world-writable.
> 
> Indeed. The file initially gets created as a mode-600 file, but the code
> later tweaks the permissions to match the symlink, which is (as you
> note) a bad thing.
> 
> My first reaction is to change the code in set_stat_xattr()
> (in xattrs.c) from:
> 
>        if (fst.st_mode != mode)
>                do_chmod(fname, mode);
> 
> to:
> 
>        if (fst.st_mode != mode && !S_ISLNK(file->mode))
>                do_chmod(fname, mode);
> 
> ..wayne.. 

That's certainly an improvement; from the safety point of view, leaving
it as 0600 is a lot better than leaving it as 0777. I'm currently
investigating a slightly more extensive fix to allow more control over
how fake-symlink files end up, also to make fake-super work better with
incoming-chmod for the daemon case.

.Dave.