RE: [RESEND v5 2/4] fs: debugfs: Add write functionality to debugfs blobs

[Luck, Tony]

> > The minimalist change here would be to s/0444/0666/
> >
> Just realized that s/0444/0644/ might be an even more minimalist change since you anyways,
> I think, need to be root for error injection through einj. Does that sound good?

You need write access. I don't think you need to be root. E.g. a validation system might
set up an "einj" group and "chmod" all these files to 0664. But that's nitpicking.

>
> In any case, using 0666 will result in the below checkpatch warning:
>
> [root avadnaik-linux]# ./scripts/checkpatch.pl --strict -g HEAD
> WARNING: Exporting world writable files is usually an error. Consider more restrictive permissions.
> #84: FILE: fs/debugfs/file.c:1063:
> +       return debugfs_create_file_unsafe(name, mode & 0666, parent, blob, &fops_blob);
>
> total: 0 errors, 1 warnings, 0 checks, 54 lines checked

The warning is dubious. This code isn't necessarily exporting a world writeable file. But
it does allow a caller of this routine to do that.

>
> Would you be okay with s/0444/0644/?

> -       return debugfs_create_file_unsafe(name, mode & 0444, parent, blob, &fops_blob);
> +       return debugfs_create_file_unsafe(name, mode & 0644, parent, blob, &fops_blob);


Yes. This is fine (better). Make sure to mention in the commit comment that this allows
callers to create files writeable by owner.

-Tony