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From: Kees Cook <keescook@chromium.org>
To: Jann Horn <jannh@google.com>
Cc: kernel list <linux-kernel@vger.kernel.org>,
	stable <stable@vger.kernel.org>,
	Sargun Dhillon <sargun@sargun.me>,
	Christian Brauner <christian@brauner.io>,
	Tycho Andersen <tycho@tycho.ws>,
	David Laight <David.Laight@aculab.com>,
	Christoph Hellwig <hch@lst.de>,
	"David S. Miller" <davem@davemloft.net>,
	Jakub Kicinski <kuba@kernel.org>,
	Alexander Viro <viro@zeniv.linux.org.uk>,
	Aleksa Sarai <cyphar@cyphar.com>,
	Matt Denton <mpdenton@google.com>,
	Chris Palmer <palmer@google.com>,
	Robert Sesek <rsesek@google.com>,
	Giuseppe Scrivano <gscrivan@redhat.com>,
	Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
	Andy Lutomirski <luto@amacapital.net>,
	Will Drewry <wad@chromium.org>, Shuah Khan <shuah@kernel.org>,
	Network Development <netdev@vger.kernel.org>,
	Linux Containers <containers@lists.linux-foundation.org>,
	Linux API <linux-api@vger.kernel.org>,
	linux-fsdevel <linux-fsdevel@vger.kernel.org>,
	"open list:KERNEL SELFTEST FRAMEWORK" 
	<linux-kselftest@vger.kernel.org>
Subject: Re: [PATCH v7 2/9] pidfd: Add missing sock updates for pidfd_getfd()
Date: Thu, 9 Jul 2020 15:35:26 -0700	[thread overview]
Message-ID: <202007091534.382887A@keescook> (raw)
In-Reply-To: <CAG48ez1gz3mtAO5QdvGEMt5KnRBq7hhWJMGS6piGDrcGNEdSrQ@mail.gmail.com>

On Thu, Jul 09, 2020 at 10:00:42PM +0200, Jann Horn wrote:
> On Thu, Jul 9, 2020 at 8:26 PM Kees Cook <keescook@chromium.org> wrote:
> > The sock counting (sock_update_netprioidx() and sock_update_classid())
> > was missing from pidfd's implementation of received fd installation. Add
> > a call to the new __receive_sock() helper.
> [...]
> > diff --git a/kernel/pid.c b/kernel/pid.c
> [...]
> > @@ -642,10 +643,12 @@ static int pidfd_getfd(struct pid *pid, int fd)
> >         }
> >
> >         ret = get_unused_fd_flags(O_CLOEXEC);
> > -       if (ret < 0)
> > +       if (ret < 0) {
> >                 fput(file);
> > -       else
> > +       } else {
> >                 fd_install(ret, file);
> > +               __receive_sock(file);
> > +       }
> 
> __receive_sock() has to be before fd_install(), otherwise `file` can
> be a dangling pointer.

I've swapped the order now and double-checked the other uses. Everything
else seems fine.

-- 
Kees Cook

  parent reply	other threads:[~2020-07-09 22:35 UTC|newest]

Thread overview: 19+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-07-09 18:26 [PATCH v7 0/9] Add seccomp notifier ioctl that enables adding fds Kees Cook
2020-07-09 18:26 ` [PATCH v7 1/9] net/compat: Add missing sock updates for SCM_RIGHTS Kees Cook
2020-07-10 11:28   ` Christian Brauner
2020-07-09 18:26 ` [PATCH v7 2/9] pidfd: Add missing sock updates for pidfd_getfd() Kees Cook
2020-07-09 20:00   ` Jann Horn
2020-07-09 21:17     ` Kees Cook
2020-07-09 22:35     ` Kees Cook [this message]
2020-07-09 18:26 ` [PATCH v7 3/9] net/scm: Regularize compat handling of scm_detach_fds() Kees Cook
2020-08-07 20:29   ` John Stultz
2020-08-07 22:18     ` Kees Cook
2020-08-08  0:02       ` John Stultz
2020-08-08  7:17         ` Kees Cook
2020-07-09 18:26 ` [PATCH v7 4/9] fs: Move __scm_install_fd() to __receive_fd() Kees Cook
2020-07-09 18:26 ` [PATCH v7 5/9] fs: Add receive_fd() wrapper for __receive_fd() Kees Cook
2020-07-09 18:26 ` [PATCH v7 6/9] pidfd: Replace open-coded receive_fd() Kees Cook
2020-07-09 18:26 ` [PATCH v7 7/9] fs: Expand __receive_fd() to accept existing fd Kees Cook
2020-07-09 18:26 ` [PATCH v7 8/9] seccomp: Introduce addfd ioctl to seccomp user notifier Kees Cook
2020-07-14 18:20   ` Will Drewry
2020-07-09 18:26 ` [PATCH v7 9/9] selftests/seccomp: Test SECCOMP_IOCTL_NOTIF_ADDFD Kees Cook

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