From: Kees Cook <keescook@chromium.org>
To: Christian Brauner <christian.brauner@ubuntu.com>
Cc: "David S. Miller" <davem@davemloft.net>,
Christoph Hellwig <hch@lst.de>,
Christian Brauner <christian@brauner.io>,
Sargun Dhillon <sargun@sargun.me>,
Jakub Kicinski <kuba@kernel.org>,
netdev@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH 0/2] Use __scm_install_fd() more widely
Date: Wed, 10 Jun 2020 10:03:03 -0700 [thread overview]
Message-ID: <202006101001.6738CA0@keescook> (raw)
In-Reply-To: <20200610094735.7ewsvrfhhpioq5xe@wittgenstein>
On Wed, Jun 10, 2020 at 11:47:35AM +0200, Christian Brauner wrote:
> On Tue, Jun 09, 2020 at 09:52:12PM -0700, Kees Cook wrote:
> > Hi,
> >
> > This extends the recent work hch did for scm_detach_fds(), and updates
> > the compat path as well, fixing bugs in the process. Additionally,
> > an effectively incomplete and open-coded __scm_install_fd() is fixed
> > in pidfd_getfd().
>
> Since __scm_detach_fds() becomes something that is available outside of
> net/* should we provide a static inline wrapper under a different name? The
> "socket-level control message" prefix seems a bit odd in pidfd_getfd()
> and - once we make use of it there - seccomp.
>
> I'd suggest we do:
>
> static inline int fd_install_received(struct file *file, unsigned int flags)
> {
> return __scm_install_fd(file, NULL, flags);
> }
>
> which can be called in pidfd_getfd() and once we have other callers that
> want the additional put_user() (e.g. seccomp_ in there we simply add:
>
> static inline fd_install_user(struct file *file, unsigned int flags, int __user *ufd)
> {
> return __scm_install_fd(file, ufd, flags);
> }
>
> and seems the wrappers both could happily live in the fs part of the world?
I combined your and Sargun's suggestions. (It can't live in any more
net/core/scm.c in the case of CONFIG_NET=n, but the wrappers make the
changes much nicer looking.)
https://git.kernel.org/pub/scm/linux/kernel/git/kees/linux.git/log/?h=devel/seccomp/addfd/v3.2
If 0-day doesn't kick anything back on this tree, I'll resend the
series...
--
Kees Cook
next prev parent reply other threads:[~2020-06-10 17:03 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-06-10 4:52 [PATCH 0/2] Use __scm_install_fd() more widely Kees Cook
2020-06-10 4:52 ` [PATCH 1/2] net/scm: Regularize compat handling of scm_detach_fds() Kees Cook
2020-06-10 4:52 ` [PATCH 2/2] pidfd: Replace open-coded partial __scm_install_fd() Kees Cook
2020-06-10 16:45 ` Sargun Dhillon
2020-06-10 9:47 ` [PATCH 0/2] Use __scm_install_fd() more widely Christian Brauner
2020-06-10 14:52 ` Kees Cook
2020-06-10 17:03 ` Kees Cook [this message]
2020-06-10 18:38 ` Jakub Kicinski
2020-06-10 19:45 ` Kees Cook
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