From: Kuniyuki Iwashima <kuniyu@amazon.com>
To: <hca@linux.ibm.com>
Cc: <aleksandr.mikhalitsyn@canonical.com>, <arnd@arndb.de>,
<bluca@debian.org>, <brauner@kernel.org>, <davem@davemloft.net>,
<dsahern@kernel.org>, <edumazet@google.com>,
<keescook@chromium.org>, <kuba@kernel.org>, <kuniyu@amazon.com>,
<ldv@strace.io>, <leon@kernel.org>, <linux-arch@vger.kernel.org>,
<linux-kernel@vger.kernel.org>, <mzxreary@0pointer.de>,
<netdev@vger.kernel.org>, <pabeni@redhat.com>
Subject: Re: [PATCH net-next v7 1/4] scm: add SO_PASSPIDFD and SCM_PIDFD
Date: Fri, 1 Sep 2023 13:56:13 -0700 [thread overview]
Message-ID: <20230901205613.59455-1-kuniyu@amazon.com> (raw)
In-Reply-To: <20230901205145.10640-A-hca@linux.ibm.com>
From: Heiko Carstens <hca@linux.ibm.com>
Date: Fri, 1 Sep 2023 22:51:45 +0200
> On Fri, Sep 01, 2023 at 01:33:22PM -0700, Kuniyuki Iwashima wrote:
> > From: Heiko Carstens <hca@linux.ibm.com>
> > Date: Fri, 1 Sep 2023 22:05:17 +0200
> > > On Thu, Jun 08, 2023 at 10:26:25PM +0200, Alexander Mikhalitsyn wrote:
> > > > + if ((msg->msg_controllen <= sizeof(struct cmsghdr)) ||
> > > > + (msg->msg_controllen - sizeof(struct cmsghdr)) < sizeof(int)) {
> > > > + msg->msg_flags |= MSG_CTRUNC;
> > > > + return;
> > > > + }
> > >
> > > This does not work for compat tasks since the size of struct cmsghdr (aka
> > > struct compat_cmsghdr) is differently. If the check from put_cmsg() is
> > > open-coded here, then also a different check for compat tasks needs to be
> > > added.
> > >
> > > Discovered this because I was wondering why strace compat tests fail; it
> > > seems because of this.
> > >
> > > See https://github.com/strace/strace/blob/master/tests/scm_pidfd.c
> > >
> > > For compat tasks recvmsg() returns with msg_flags=MSG_CTRUNC since the
> > > above code expects a larger buffer than is necessary.
> >
> > Can you test this ?
>
> Works for me.
>
> Tested-by: Heiko Carstens <hca@linux.ibm.com>
Thanks!
I'll post a formal patch.
next prev parent reply other threads:[~2023-09-01 20:56 UTC|newest]
Thread overview: 16+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-06-08 20:26 [PATCH net-next v7 0/4] Add SCM_PIDFD and SO_PEERPIDFD Alexander Mikhalitsyn
2023-06-08 20:26 ` [PATCH net-next v7 1/4] scm: add SO_PASSPIDFD and SCM_PIDFD Alexander Mikhalitsyn
2023-06-12 9:19 ` Eric Dumazet
2023-06-12 9:26 ` Aleksandr Mikhalitsyn
2023-09-01 20:05 ` Heiko Carstens
2023-09-01 20:33 ` Kuniyuki Iwashima
2023-09-01 20:51 ` Heiko Carstens
2023-09-01 20:56 ` Kuniyuki Iwashima [this message]
2023-09-01 21:11 ` Aleksandr Mikhalitsyn
2023-06-08 20:26 ` [PATCH net-next v7 2/4] net: core: add getsockopt SO_PEERPIDFD Alexander Mikhalitsyn
2023-06-12 9:22 ` Eric Dumazet
2023-06-08 20:26 ` [PATCH net-next v7 3/4] selftests: net: add SCM_PIDFD / SO_PEERPIDFD test Alexander Mikhalitsyn
2023-06-08 20:26 ` [PATCH net-next v7 4/4] af_unix: Kconfig: make CONFIG_UNIX bool Alexander Mikhalitsyn
2023-06-09 8:06 ` Christian Brauner
2023-06-12 9:25 ` Eric Dumazet
2023-06-12 9:50 ` [PATCH net-next v7 0/4] Add SCM_PIDFD and SO_PEERPIDFD patchwork-bot+netdevbpf
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