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References: <20210628123801.3511-1-wangshilong1991@gmail.com> <20210628223403.GE664593@dread.disaster.area>
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From:   Wang Shilong <wangshilong1991@gmail.com>
Date:   Thu, 1 Jul 2021 23:37:33 +0800
Message-ID: <CAP9B-QnCjz4UTALx0W4QA=7qTcEHTVOVid+kJW8Te-dgJoobHg@mail.gmail.com>
Subject: Re: [PATCH v2] fs: forbid invalid project ID
To:     Dave Chinner <david@fromorbit.com>
Cc:     linux-fsdevel@vger.kernel.org, linux-xfs@vger.kernel.org,
        Ext4 Developers List <linux-ext4@vger.kernel.org>,
        linux-f2fs-devel@lists.sourceforge.net
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On Tue, Jun 29, 2021 at 6:34 AM Dave Chinner <david@fromorbit.com> wrote:
>
> On Mon, Jun 28, 2021 at 08:38:01AM -0400, Wang Shilong wrote:
> > fileattr_set_prepare() should check if project ID
> > is valid, otherwise dqget() will return NULL for
> > such project ID quota.
> >
> > Signed-off-by: Wang Shilong <wshilong@ddn.com>
> > ---
> > v1->v2: try to fix in the VFS
> > ---
> >  fs/ioctl.c | 3 +++
> >  1 file changed, 3 insertions(+)
> >
> > diff --git a/fs/ioctl.c b/fs/ioctl.c
> > index 1e2204fa9963..5db5b218637b 100644
> > --- a/fs/ioctl.c
> > +++ b/fs/ioctl.c
> > @@ -845,6 +845,9 @@ static int fileattr_set_prepare(struct inode *inode,
> >       if (fa->fsx_cowextsize == 0)
> >               fa->fsx_xflags &= ~FS_XFLAG_COWEXTSIZE;
> >
> > +     if (!projid_valid(KPROJIDT_INIT(fa->fsx_projid)))
> > +             return -EINVAL;
>
> This needs to go further up in this function in the section where
> project IDs passed into this function are validated. Projids are
> only allowed to be changed when current_user_ns() == &init_user_ns,
> so this needs to be associated with that verification context.
>
> This check should also use make_kprojid(), please, not open code
> KPROJIDT_INIT.

You are right, let me send a V3

>
> Cheers,
>
> Dave.
> --
> Dave Chinner
> david@fromorbit.com