From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 37BBDC77B6F for ; Tue, 11 Apr 2023 15:57:50 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230177AbjDKP5t (ORCPT ); Tue, 11 Apr 2023 11:57:49 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:48026 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230339AbjDKP5q (ORCPT ); Tue, 11 Apr 2023 11:57:46 -0400 Received: from dfw.source.kernel.org (dfw.source.kernel.org [139.178.84.217]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id CF71DE7B; Tue, 11 Apr 2023 08:57:44 -0700 (PDT) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by dfw.source.kernel.org (Postfix) with ESMTPS id 6B3E462807; Tue, 11 Apr 2023 15:57:44 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 4E8E7C433EF; Tue, 11 Apr 2023 15:57:40 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1681228663; bh=Hdp/O4sWkXQQLjlMeKKnQiGPMpZXSJyElbG/I6uZC2k=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=BP4XJv5U6an713Mb8FIiRbB0lxcHDfKTYmY2jXC1shtmLoRge1Irdgy/ptNV98a8I lFk9PJOaHivyyxrhbUbZgAVVHoppaSYiAay6XIHSpztneMBBbsRs7GOPiCJCpkQc2H Y7qzqz7QVqWRykxy/ASiaq1srPlLvPz5XoaEJxIYfaVTnwiY7+IKi7nm6m6q+2REKI brselQs96d9XAyH9c6t+vlfjHNyExql4aDekp77MKxJfJtX0AEQWkQkejaabyrmqjR 69aeeSxO2SffZyGW7iUcKG/nJ1jfVe1cJPRi7KUkEyhkOkcRH1lb9aSLE6RS/p5dpw 2kxqmOdYbZjvA== Date: Tue, 11 Apr 2023 17:57:31 +0200 From: Christian Brauner To: Alexander Mikhalitsyn Cc: davem@davemloft.net, linux-kernel@vger.kernel.org, netdev@vger.kernel.org, Eric Dumazet , Jakub Kicinski , Paolo Abeni , Leon Romanovsky , David Ahern , Arnd Bergmann , Kees Cook , Kuniyuki Iwashima , Lennart Poettering , Luca Boccassi , linux-arch@vger.kernel.org Subject: Re: [PATCH net-next v3 3/4] net: core: add getsockopt SO_PEERPIDFD Message-ID: <20230411-pantoffeln-voreilig-208e37ba62bb@brauner> References: <20230411104231.160837-1-aleksandr.mikhalitsyn@canonical.com> <20230411104231.160837-4-aleksandr.mikhalitsyn@canonical.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <20230411104231.160837-4-aleksandr.mikhalitsyn@canonical.com> Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org On Tue, Apr 11, 2023 at 12:42:30PM +0200, Alexander Mikhalitsyn wrote: > Add SO_PEERPIDFD which allows to get pidfd of peer socket holder pidfd. > This thing is direct analog of SO_PEERCRED which allows to get plain PID. > > Cc: "David S. Miller" > Cc: Eric Dumazet > Cc: Jakub Kicinski > Cc: Paolo Abeni > Cc: Leon Romanovsky > Cc: David Ahern > Cc: Arnd Bergmann > Cc: Kees Cook > Cc: Christian Brauner > Cc: Kuniyuki Iwashima > Cc: Lennart Poettering > Cc: Luca Boccassi > Cc: linux-kernel@vger.kernel.org > Cc: netdev@vger.kernel.org > Cc: linux-arch@vger.kernel.org > Tested-by: Luca Boccassi > Signed-off-by: Alexander Mikhalitsyn > --- > v3: > - fixed possible fd leak (thanks to Christian Brauner) > v2: > According to review comments from Kuniyuki Iwashima and Christian Brauner: > - use pidfd_create(..) retval as a result > - whitespace change > --- > arch/alpha/include/uapi/asm/socket.h | 1 + > arch/mips/include/uapi/asm/socket.h | 1 + > arch/parisc/include/uapi/asm/socket.h | 1 + > arch/sparc/include/uapi/asm/socket.h | 1 + > include/uapi/asm-generic/socket.h | 1 + > net/core/sock.c | 33 +++++++++++++++++++++++++ > net/socket.c | 7 ++++++ > tools/include/uapi/asm-generic/socket.h | 1 + > 8 files changed, 46 insertions(+) > > diff --git a/arch/alpha/include/uapi/asm/socket.h b/arch/alpha/include/uapi/asm/socket.h > index ff310613ae64..e94f621903fe 100644 > --- a/arch/alpha/include/uapi/asm/socket.h > +++ b/arch/alpha/include/uapi/asm/socket.h > @@ -138,6 +138,7 @@ > #define SO_RCVMARK 75 > > #define SO_PASSPIDFD 76 > +#define SO_PEERPIDFD 77 > > #if !defined(__KERNEL__) > > diff --git a/arch/mips/include/uapi/asm/socket.h b/arch/mips/include/uapi/asm/socket.h > index 762dcb80e4ec..60ebaed28a4c 100644 > --- a/arch/mips/include/uapi/asm/socket.h > +++ b/arch/mips/include/uapi/asm/socket.h > @@ -149,6 +149,7 @@ > #define SO_RCVMARK 75 > > #define SO_PASSPIDFD 76 > +#define SO_PEERPIDFD 77 > > #if !defined(__KERNEL__) > > diff --git a/arch/parisc/include/uapi/asm/socket.h b/arch/parisc/include/uapi/asm/socket.h > index df16a3e16d64..be264c2b1a11 100644 > --- a/arch/parisc/include/uapi/asm/socket.h > +++ b/arch/parisc/include/uapi/asm/socket.h > @@ -130,6 +130,7 @@ > #define SO_RCVMARK 0x4049 > > #define SO_PASSPIDFD 0x404A > +#define SO_PEERPIDFD 0x404B > > #if !defined(__KERNEL__) > > diff --git a/arch/sparc/include/uapi/asm/socket.h b/arch/sparc/include/uapi/asm/socket.h > index 6e2847804fea..682da3714686 100644 > --- a/arch/sparc/include/uapi/asm/socket.h > +++ b/arch/sparc/include/uapi/asm/socket.h > @@ -131,6 +131,7 @@ > #define SO_RCVMARK 0x0054 > > #define SO_PASSPIDFD 0x0055 > +#define SO_PEERPIDFD 0x0056 > > #if !defined(__KERNEL__) > > diff --git a/include/uapi/asm-generic/socket.h b/include/uapi/asm-generic/socket.h > index b76169fdb80b..8ce8a39a1e5f 100644 > --- a/include/uapi/asm-generic/socket.h > +++ b/include/uapi/asm-generic/socket.h > @@ -133,6 +133,7 @@ > #define SO_RCVMARK 75 > > #define SO_PASSPIDFD 76 > +#define SO_PEERPIDFD 77 > > #if !defined(__KERNEL__) > > diff --git a/net/core/sock.c b/net/core/sock.c > index 3f974246ba3e..2b040a69e355 100644 > --- a/net/core/sock.c > +++ b/net/core/sock.c > @@ -1763,6 +1763,39 @@ int sk_getsockopt(struct sock *sk, int level, int optname, > goto lenout; > } > > + case SO_PEERPIDFD: > + { > + struct pid *peer_pid; > + struct file *pidfd_file = NULL; > + int pidfd; > + > + if (len > sizeof(pidfd)) > + len = sizeof(pidfd); > + > + spin_lock(&sk->sk_peer_lock); > + peer_pid = get_pid(sk->sk_peer_pid); > + spin_unlock(&sk->sk_peer_lock); > + > + pidfd = pidfd_prepare(peer_pid, 0, &pidfd_file); > + > + put_pid(peer_pid); Would be a bit nicer if this would be: pidfd = pidfd_prepare(peer_pid, 0, &pidfd_file); put_pid(peer_pid); if (pidfd < 0) return pidfd; if (copy_to_sockptr(optval, &pidfd, len) || copy_to_sockptr(optlen, &len, sizeof(int))) return -EFAULT; fd_install(pidfd, pidfd_file); return 0; Otherwise seems good enough to me. > + > + if (copy_to_sockptr(optval, &pidfd, len) || > + copy_to_sockptr(optlen, &len, sizeof(int))) { > + if (pidfd >= 0) { > + put_unused_fd(pidfd); > + fput(pidfd_file); > + } > + > + return -EFAULT; > + } > + > + if (pidfd_file) > + fd_install(pidfd, pidfd_file); > + > + return 0; > + } > + > case SO_PEERGROUPS: > { > const struct cred *cred; > diff --git a/net/socket.c b/net/socket.c > index 9c1ef11de23f..505b85489354 100644 > --- a/net/socket.c > +++ b/net/socket.c > @@ -2248,6 +2248,13 @@ static bool sockopt_installs_fd(int level, int optname) > default: > return false; > } > + } else if (level == SOL_SOCKET) { > + switch (optname) { > + case SO_PEERPIDFD: > + return true; > + default: > + return false; > + } > } > > return false; > diff --git a/tools/include/uapi/asm-generic/socket.h b/tools/include/uapi/asm-generic/socket.h > index fbbc4bf53ee3..54d9c8bf7c55 100644 > --- a/tools/include/uapi/asm-generic/socket.h > +++ b/tools/include/uapi/asm-generic/socket.h > @@ -122,6 +122,7 @@ > #define SO_RCVMARK 75 > > #define SO_PASSPIDFD 76 > +#define SO_PEERPIDFD 77 > > #if !defined(__KERNEL__) > > -- > 2.34.1 >