From: Christoph Hellwig <hch@infradead.org>
To: Rich Felker <dalias@libc.org>
Cc: Christoph Hellwig <hch@infradead.org>,
linux-api@vger.kernel.org,
Alexander Viro <viro@zeniv.linux.org.uk>,
linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH] vfs: add fchmodat2 syscall
Date: Thu, 10 Sep 2020 17:42:34 +0100 [thread overview]
Message-ID: <20200910164234.GA25140@infradead.org> (raw)
In-Reply-To: <20200910163949.GJ3265@brightrain.aerifal.cx>
On Thu, Sep 10, 2020 at 12:39:50PM -0400, Rich Felker wrote:
> On Thu, Sep 10, 2020 at 05:20:59PM +0100, Christoph Hellwig wrote:
> > On Thu, Sep 10, 2020 at 10:23:37AM -0400, Rich Felker wrote:
> > > userspace emulation done in libc implementations. No change is made to
> > > the underlying chmod_common(), so it's still possible to attempt
> > > changes via procfs, if desired.
> >
> > And that is the goddamn problem. We need to fix that _first_.
>
> Can you clarify exactly what that is? Do you mean fixing the
> underlying fs backends, or just ensuring that the chmod for symlinks
> doesn't reach them by putting the check in chmod_common? I'm ok with
> any of these.
Either - we need to make sure the user can't change the permission
bits.
> > After that we can add sugarcoating using new syscalls if needed.
>
> The new syscall is _not_ about this problem. It's about the missing
> flags argument and inability to implement fchmodat() without access to
> procfs. The above problem is just something you encounter and have to
> make a decision about in order to fix the missing flags problem and
> make a working AT_SYMLINK_NOFOLLOW.
And I'm generally supportive of that. But we need to fix the damn
bug first an then do nice to haves.
next prev parent reply other threads:[~2020-09-10 16:49 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-09-10 14:23 [PATCH] vfs: add fchmodat2 syscall Rich Felker
2020-09-10 15:18 ` Al Viro
2020-09-10 15:45 ` Rich Felker
2020-09-10 15:23 ` David Laight
2020-09-10 16:16 ` Greg KH
2020-09-10 16:35 ` Rich Felker
2020-09-10 16:20 ` Christoph Hellwig
2020-09-10 16:39 ` Rich Felker
2020-09-10 16:42 ` Christoph Hellwig [this message]
2020-09-10 17:02 ` Rich Felker
2020-09-11 6:57 ` Christoph Hellwig
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