From nobody Wed Feb 11 07:26:15 2026 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 36654C6FD1F for ; Thu, 16 Mar 2023 13:17:14 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230105AbjCPNRK (ORCPT ); Thu, 16 Mar 2023 09:17:10 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:58420 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230088AbjCPNRF (ORCPT ); Thu, 16 Mar 2023 09:17:05 -0400 Received: from smtp-relay-internal-0.canonical.com (smtp-relay-internal-0.canonical.com [185.125.188.122]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id E4D4DC97CD for ; Thu, 16 Mar 2023 06:16:54 -0700 (PDT) Received: from mail-ed1-f69.google.com (mail-ed1-f69.google.com [209.85.208.69]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits) server-digest SHA256) (No client certificate requested) by smtp-relay-internal-0.canonical.com (Postfix) with ESMTPS id E436D4460B for ; Thu, 16 Mar 2023 13:16:52 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=canonical.com; s=20210705; t=1678972612; bh=+MIwejgyU+YIhZQN55WZnro6zd2U2nJ4DbEoCPMF/b4=; h=From:To:Cc:Subject:Date:Message-Id:In-Reply-To:References: MIME-Version; b=YHY+4SpuS8BESsMVnGLNl4kyp8LDKhY2Ba36AW1RZ1Z+/XME/CImEXPJoRY0DlSEC SIoGbpweDrsANVmNAUgePiHnadmQ8SawC8rcHeKCXEifshCPLF4aVqOXUk8FtugZKn HBETXPdc5CGPUzkC8OjaHLD0URFavOyYbjvYnX7Krnq2MZSDNdAVrkKW11KdJqkfFT JxCSKO4k2lg3wOUeqdRFgY+nthPcXRK+BP17cwQnD1be0F44TpdlxxdzADapENQYN/ Mi+6MSPZWOoHi1z5gp5RLlZFycXFXM/S4RtqT7wkO97tbX+2n9DaoDJzraT8bel0zC usnOpQBDzqGBA== Received: by mail-ed1-f69.google.com with SMTP id c1-20020a0564021f8100b004acbe232c03so2974892edc.9 for ; Thu, 16 Mar 2023 06:16:52 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; t=1678972612; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:x-gm-message-state:from:to:cc :subject:date:message-id:reply-to; bh=+MIwejgyU+YIhZQN55WZnro6zd2U2nJ4DbEoCPMF/b4=; b=B9SBrin9nrH699XqZRcB8ihYPHiqaJXKLMCQ+kaN8KeBCPYXXIrcxWFoapAHrBDGJs 79ipicqa+A4oFjStjq1l5FolwUhlEFw0xADQ4bGVc80jCh/Xv8L7I8L2RUe8YKiLacRT MdKoLaeJwv8orbKU2O6jICpoiisRWd2rGF2DM7fDL6qyQkHUs702mVVkt/5OWZIv/Z4F 8/Qwyah1mX5tb1NHmnF6rwpnmiMRBL596wvTHFXynyazKBpXWzlErxl3+kl9w+aiRRHC TLy3DL7whbrbCTM6Lj0WJdCyH+e4vUc6JoCgefX0UsrJy8q5MZe3jEZf/g+hMfLGkgba OJ2A== X-Gm-Message-State: AO0yUKUKMTqbenwFY6uXu7Ek0P1XF18VG4vf+GOsP10FbvTZeUOM3+A+ 5zhAo12N/Q4kKF5KblRIgyYYb58lWVNkIKetUM1BO3xqxGWBtRI5uPZ0fyCCY7ANT86NnVV9vm0 u7G5FVfhijgbYu5BGHN+Ji1X+KiAH+PZiD5FpkJNoiA== X-Received: by 2002:a17:906:f1c6:b0:930:f953:9614 with SMTP id gx6-20020a170906f1c600b00930f9539614mr939672ejb.1.1678972611973; Thu, 16 Mar 2023 06:16:51 -0700 (PDT) X-Google-Smtp-Source: AK7set8V/lOFb1LgYVO3ll64397gV8ZXvwX4voI0tL/mZcT6K9s4xeIFhKK6sp9zDKsHJ9HGiBEUBA== X-Received: by 2002:a17:906:f1c6:b0:930:f953:9614 with SMTP id gx6-20020a170906f1c600b00930f9539614mr939646ejb.1.1678972611709; Thu, 16 Mar 2023 06:16:51 -0700 (PDT) Received: from amikhalitsyn.. ([2a02:8109:bd40:1414:5e7c:880e:420d:8cc7]) by smtp.gmail.com with ESMTPSA id d20-20020a50cd54000000b004fd1ee3f723sm3812336edj.67.2023.03.16.06.16.50 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 16 Mar 2023 06:16:51 -0700 (PDT) From: Alexander Mikhalitsyn To: davem@davemloft.net Cc: linux-kernel@vger.kernel.org, netdev@vger.kernel.org, Alexander Mikhalitsyn , Eric Dumazet , Jakub Kicinski , Paolo Abeni , Leon Romanovsky , David Ahern , Arnd Bergmann , Kees Cook , Christian Brauner , linux-arch@vger.kernel.org Subject: [PATCH net-next 1/3] scm: add SO_PASSPIDFD and SCM_PIDFD Date: Thu, 16 Mar 2023 14:15:24 +0100 Message-Id: <20230316131526.283569-2-aleksandr.mikhalitsyn@canonical.com> X-Mailer: git-send-email 2.34.1 In-Reply-To: <20230316131526.283569-1-aleksandr.mikhalitsyn@canonical.com> References: <20230316131526.283569-1-aleksandr.mikhalitsyn@canonical.com> MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Type: text/plain; charset="utf-8" Implement SCM_PIDFD, a new type of CMSG type analogical to SCM_CREDENTIALS, but it contains pidfd instead of plain pid, which allows programmers not to care about PID reuse problem. 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: linux-kernel@vger.kernel.org Cc: netdev@vger.kernel.org Cc: linux-arch@vger.kernel.org Signed-off-by: Alexander Mikhalitsyn Tested-by: Luca Boccassi --- arch/alpha/include/uapi/asm/socket.h | 2 ++ arch/mips/include/uapi/asm/socket.h | 2 ++ arch/parisc/include/uapi/asm/socket.h | 2 ++ arch/sparc/include/uapi/asm/socket.h | 2 ++ include/linux/net.h | 1 + include/linux/socket.h | 1 + include/net/scm.h | 16 +++++++++++++++- include/uapi/asm-generic/socket.h | 2 ++ net/core/sock.c | 11 +++++++++++ net/mptcp/sockopt.c | 1 + net/unix/af_unix.c | 18 +++++++++++++----- tools/include/uapi/asm-generic/socket.h | 2 ++ 12 files changed, 54 insertions(+), 6 deletions(-) diff --git a/arch/alpha/include/uapi/asm/socket.h b/arch/alpha/include/uapi= /asm/socket.h index 739891b94136..ff310613ae64 100644 --- a/arch/alpha/include/uapi/asm/socket.h +++ b/arch/alpha/include/uapi/asm/socket.h @@ -137,6 +137,8 @@ =20 #define SO_RCVMARK 75 =20 +#define SO_PASSPIDFD 76 + #if !defined(__KERNEL__) =20 #if __BITS_PER_LONG =3D=3D 64 diff --git a/arch/mips/include/uapi/asm/socket.h b/arch/mips/include/uapi/a= sm/socket.h index 18f3d95ecfec..762dcb80e4ec 100644 --- a/arch/mips/include/uapi/asm/socket.h +++ b/arch/mips/include/uapi/asm/socket.h @@ -148,6 +148,8 @@ =20 #define SO_RCVMARK 75 =20 +#define SO_PASSPIDFD 76 + #if !defined(__KERNEL__) =20 #if __BITS_PER_LONG =3D=3D 64 diff --git a/arch/parisc/include/uapi/asm/socket.h b/arch/parisc/include/ua= pi/asm/socket.h index f486d3dfb6bb..df16a3e16d64 100644 --- a/arch/parisc/include/uapi/asm/socket.h +++ b/arch/parisc/include/uapi/asm/socket.h @@ -129,6 +129,8 @@ =20 #define SO_RCVMARK 0x4049 =20 +#define SO_PASSPIDFD 0x404A + #if !defined(__KERNEL__) =20 #if __BITS_PER_LONG =3D=3D 64 diff --git a/arch/sparc/include/uapi/asm/socket.h b/arch/sparc/include/uapi= /asm/socket.h index 2fda57a3ea86..6e2847804fea 100644 --- a/arch/sparc/include/uapi/asm/socket.h +++ b/arch/sparc/include/uapi/asm/socket.h @@ -130,6 +130,8 @@ =20 #define SO_RCVMARK 0x0054 =20 +#define SO_PASSPIDFD 0x0055 + #if !defined(__KERNEL__) =20 =20 diff --git a/include/linux/net.h b/include/linux/net.h index b73ad8e3c212..c234dfbe7a30 100644 --- a/include/linux/net.h +++ b/include/linux/net.h @@ -43,6 +43,7 @@ struct net; #define SOCK_PASSSEC 4 #define SOCK_SUPPORT_ZC 5 #define SOCK_CUSTOM_SOCKOPT 6 +#define SOCK_PASSPIDFD 7 =20 #ifndef ARCH_HAS_SOCKET_TYPES /** diff --git a/include/linux/socket.h b/include/linux/socket.h index 13c3a237b9c9..6bf90f251910 100644 --- a/include/linux/socket.h +++ b/include/linux/socket.h @@ -177,6 +177,7 @@ static inline size_t msg_data_left(struct msghdr *msg) #define SCM_RIGHTS 0x01 /* rw: access rights (array of int) */ #define SCM_CREDENTIALS 0x02 /* rw: struct ucred */ #define SCM_SECURITY 0x03 /* rw: security label */ +#define SCM_PIDFD 0x04 /* ro: pidfd (int) */ =20 struct ucred { __u32 pid; diff --git a/include/net/scm.h b/include/net/scm.h index 585adc1346bd..4617fbc65294 100644 --- a/include/net/scm.h +++ b/include/net/scm.h @@ -124,7 +124,9 @@ static __inline__ void scm_recv(struct socket *sock, st= ruct msghdr *msg, struct scm_cookie *scm, int flags) { if (!msg->msg_control) { - if (test_bit(SOCK_PASSCRED, &sock->flags) || scm->fp || + if (test_bit(SOCK_PASSCRED, &sock->flags) || + test_bit(SOCK_PASSPIDFD, &sock->flags) || + scm->fp || scm_has_secdata(sock)) msg->msg_flags |=3D MSG_CTRUNC; scm_destroy(scm); @@ -141,6 +143,18 @@ static __inline__ void scm_recv(struct socket *sock, s= truct msghdr *msg, put_cmsg(msg, SOL_SOCKET, SCM_CREDENTIALS, sizeof(ucreds), &ucreds); } =20 + if (test_bit(SOCK_PASSPIDFD, &sock->flags)) { + int pidfd; + + if (WARN_ON_ONCE(!scm->pid) || + !pid_has_task(scm->pid, PIDTYPE_TGID)) + pidfd =3D -ESRCH; + else + pidfd =3D pidfd_create(scm->pid, 0); + + put_cmsg(msg, SOL_SOCKET, SCM_PIDFD, sizeof(int), &pidfd); + } + scm_destroy_cred(scm); =20 scm_passec(sock, msg, scm); diff --git a/include/uapi/asm-generic/socket.h b/include/uapi/asm-generic/s= ocket.h index 638230899e98..b76169fdb80b 100644 --- a/include/uapi/asm-generic/socket.h +++ b/include/uapi/asm-generic/socket.h @@ -132,6 +132,8 @@ =20 #define SO_RCVMARK 75 =20 +#define SO_PASSPIDFD 76 + #if !defined(__KERNEL__) =20 #if __BITS_PER_LONG =3D=3D 64 || (defined(__x86_64__) && defined(__ILP32__= )) diff --git a/net/core/sock.c b/net/core/sock.c index c25888795390..3f974246ba3e 100644 --- a/net/core/sock.c +++ b/net/core/sock.c @@ -1246,6 +1246,13 @@ int sk_setsockopt(struct sock *sk, int level, int op= tname, clear_bit(SOCK_PASSCRED, &sock->flags); break; =20 + case SO_PASSPIDFD: + if (valbool) + set_bit(SOCK_PASSPIDFD, &sock->flags); + else + clear_bit(SOCK_PASSPIDFD, &sock->flags); + break; + case SO_TIMESTAMP_OLD: case SO_TIMESTAMP_NEW: case SO_TIMESTAMPNS_OLD: @@ -1737,6 +1744,10 @@ int sk_getsockopt(struct sock *sk, int level, int op= tname, v.val =3D !!test_bit(SOCK_PASSCRED, &sock->flags); break; =20 + case SO_PASSPIDFD: + v.val =3D !!test_bit(SOCK_PASSPIDFD, &sock->flags); + break; + case SO_PEERCRED: { struct ucred peercred; diff --git a/net/mptcp/sockopt.c b/net/mptcp/sockopt.c index 8a9656248b0f..bd80e707d0b3 100644 --- a/net/mptcp/sockopt.c +++ b/net/mptcp/sockopt.c @@ -355,6 +355,7 @@ static int mptcp_setsockopt_sol_socket(struct mptcp_soc= k *msk, int optname, case SO_BROADCAST: case SO_BSDCOMPAT: case SO_PASSCRED: + case SO_PASSPIDFD: case SO_PASSSEC: case SO_RXQ_OVFL: case SO_WIFI_STATUS: diff --git a/net/unix/af_unix.c b/net/unix/af_unix.c index 0b0f18ecce44..b0ac768752fa 100644 --- a/net/unix/af_unix.c +++ b/net/unix/af_unix.c @@ -1361,7 +1361,8 @@ static int unix_dgram_connect(struct socket *sock, st= ruct sockaddr *addr, if (err) goto out; =20 - if (test_bit(SOCK_PASSCRED, &sock->flags) && + if ((test_bit(SOCK_PASSCRED, &sock->flags) || + test_bit(SOCK_PASSPIDFD, &sock->flags)) && !unix_sk(sk)->addr) { err =3D unix_autobind(sk); if (err) @@ -1469,7 +1470,8 @@ static int unix_stream_connect(struct socket *sock, s= truct sockaddr *uaddr, if (err) goto out; =20 - if (test_bit(SOCK_PASSCRED, &sock->flags) && !u->addr) { + if ((test_bit(SOCK_PASSCRED, &sock->flags) || + test_bit(SOCK_PASSPIDFD, &sock->flags)) && !u->addr) { err =3D unix_autobind(sk); if (err) goto out; @@ -1670,6 +1672,8 @@ static void unix_sock_inherit_flags(const struct sock= et *old, { if (test_bit(SOCK_PASSCRED, &old->flags)) set_bit(SOCK_PASSCRED, &new->flags); + if (test_bit(SOCK_PASSPIDFD, &old->flags)) + set_bit(SOCK_PASSPIDFD, &new->flags); if (test_bit(SOCK_PASSSEC, &old->flags)) set_bit(SOCK_PASSSEC, &new->flags); } @@ -1819,8 +1823,10 @@ static bool unix_passcred_enabled(const struct socke= t *sock, const struct sock *other) { return test_bit(SOCK_PASSCRED, &sock->flags) || + test_bit(SOCK_PASSPIDFD, &sock->flags) || !other->sk_socket || - test_bit(SOCK_PASSCRED, &other->sk_socket->flags); + test_bit(SOCK_PASSCRED, &other->sk_socket->flags) || + test_bit(SOCK_PASSPIDFD, &other->sk_socket->flags); } =20 /* @@ -1922,7 +1928,8 @@ static int unix_dgram_sendmsg(struct socket *sock, st= ruct msghdr *msg, goto out; } =20 - if (test_bit(SOCK_PASSCRED, &sock->flags) && !u->addr) { + if ((test_bit(SOCK_PASSCRED, &sock->flags) || + test_bit(SOCK_PASSPIDFD, &sock->flags)) && !u->addr) { err =3D unix_autobind(sk); if (err) goto out; @@ -2824,7 +2831,8 @@ static int unix_stream_read_generic(struct unix_strea= m_read_state *state, /* Never glue messages from different writers */ if (!unix_skb_scm_eq(skb, &scm)) break; - } else if (test_bit(SOCK_PASSCRED, &sock->flags)) { + } else if (test_bit(SOCK_PASSCRED, &sock->flags) || + test_bit(SOCK_PASSPIDFD, &sock->flags)) { /* Copy credentials */ scm_set_cred(&scm, UNIXCB(skb).pid, UNIXCB(skb).uid, UNIXCB(skb).gid); unix_set_secdata(&scm, skb); diff --git a/tools/include/uapi/asm-generic/socket.h b/tools/include/uapi/a= sm-generic/socket.h index 8756df13be50..fbbc4bf53ee3 100644 --- a/tools/include/uapi/asm-generic/socket.h +++ b/tools/include/uapi/asm-generic/socket.h @@ -121,6 +121,8 @@ =20 #define SO_RCVMARK 75 =20 +#define SO_PASSPIDFD 76 + #if !defined(__KERNEL__) =20 #if __BITS_PER_LONG =3D=3D 64 || (defined(__x86_64__) && defined(__ILP32__= )) --=20 2.34.1 From nobody Wed Feb 11 07:26:15 2026 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 3E538C7618D for ; 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([2a02:8109:bd40:1414:5e7c:880e:420d:8cc7]) by smtp.gmail.com with ESMTPSA id d20-20020a50cd54000000b004fd1ee3f723sm3812336edj.67.2023.03.16.06.17.04 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 16 Mar 2023 06:17:04 -0700 (PDT) From: Alexander Mikhalitsyn To: davem@davemloft.net Cc: linux-kernel@vger.kernel.org, netdev@vger.kernel.org, Alexander Mikhalitsyn , Eric Dumazet , Jakub Kicinski , Paolo Abeni , Leon Romanovsky , David Ahern , Arnd Bergmann , Kees Cook , Christian Brauner , linux-arch@vger.kernel.org Subject: [PATCH net-next 2/3] net: core: add getsockopt SO_PEERPIDFD Date: Thu, 16 Mar 2023 14:15:25 +0100 Message-Id: <20230316131526.283569-3-aleksandr.mikhalitsyn@canonical.com> X-Mailer: git-send-email 2.34.1 In-Reply-To: <20230316131526.283569-1-aleksandr.mikhalitsyn@canonical.com> References: <20230316131526.283569-1-aleksandr.mikhalitsyn@canonical.com> MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Type: text/plain; charset="utf-8" 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: linux-kernel@vger.kernel.org Cc: netdev@vger.kernel.org Cc: linux-arch@vger.kernel.org Signed-off-by: Alexander Mikhalitsyn Tested-by: Luca Boccassi --- 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 | 24 ++++++++++++++++++++++++ tools/include/uapi/asm-generic/socket.h | 1 + 7 files changed, 30 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 =20 #define SO_PASSPIDFD 76 +#define SO_PEERPIDFD 77 =20 #if !defined(__KERNEL__) =20 diff --git a/arch/mips/include/uapi/asm/socket.h b/arch/mips/include/uapi/a= sm/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 =20 #define SO_PASSPIDFD 76 +#define SO_PEERPIDFD 77 =20 #if !defined(__KERNEL__) =20 diff --git a/arch/parisc/include/uapi/asm/socket.h b/arch/parisc/include/ua= pi/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 =20 #define SO_PASSPIDFD 0x404A +#define SO_PEERPIDFD 0x404B =20 #if !defined(__KERNEL__) =20 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 =20 #define SO_PASSPIDFD 0x0055 +#define SO_PEERPIDFD 0x0056 =20 #if !defined(__KERNEL__) =20 diff --git a/include/uapi/asm-generic/socket.h b/include/uapi/asm-generic/s= ocket.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 =20 #define SO_PASSPIDFD 76 +#define SO_PEERPIDFD 77 =20 #if !defined(__KERNEL__) =20 diff --git a/net/core/sock.c b/net/core/sock.c index 3f974246ba3e..3aa1ccd4bcf3 100644 --- a/net/core/sock.c +++ b/net/core/sock.c @@ -1763,6 +1763,30 @@ int sk_getsockopt(struct sock *sk, int level, int op= tname, goto lenout; } =20 + case SO_PEERPIDFD: + { + struct pid *peer_pid; + int pidfd; + if (len > sizeof(pidfd)) + len =3D sizeof(pidfd); + + spin_lock(&sk->sk_peer_lock); + peer_pid =3D get_pid(sk->sk_peer_pid); + spin_unlock(&sk->sk_peer_lock); + + if (!peer_pid || + !pid_has_task(peer_pid, PIDTYPE_TGID)) + pidfd =3D -ESRCH; + else + pidfd =3D pidfd_create(peer_pid, 0); + + put_pid(peer_pid); + + if (copy_to_sockptr(optval, &pidfd, len)) + return -EFAULT; + goto lenout; + } + case SO_PEERGROUPS: { const struct cred *cred; diff --git a/tools/include/uapi/asm-generic/socket.h b/tools/include/uapi/a= sm-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 =20 #define SO_PASSPIDFD 76 +#define SO_PEERPIDFD 77 =20 #if !defined(__KERNEL__) =20 --=20 2.34.1 From nobody Wed Feb 11 07:26:15 2026 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 11FFBC6FD19 for ; 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([2a02:8109:bd40:1414:5e7c:880e:420d:8cc7]) by smtp.gmail.com with ESMTPSA id d20-20020a50cd54000000b004fd1ee3f723sm3812336edj.67.2023.03.16.06.17.10 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 16 Mar 2023 06:17:11 -0700 (PDT) From: Alexander Mikhalitsyn To: davem@davemloft.net Cc: linux-kernel@vger.kernel.org, netdev@vger.kernel.org, Alexander Mikhalitsyn , Eric Dumazet , Jakub Kicinski , Paolo Abeni , Leon Romanovsky , David Ahern , Arnd Bergmann , Kees Cook , Christian Brauner , linux-arch@vger.kernel.org, linux-kselftest@vger.kernel.org Subject: [PATCH net-next 3/3] selftests: net: add SCM_PIDFD / SO_PEERPIDFD test Date: Thu, 16 Mar 2023 14:15:26 +0100 Message-Id: <20230316131526.283569-4-aleksandr.mikhalitsyn@canonical.com> X-Mailer: git-send-email 2.34.1 In-Reply-To: <20230316131526.283569-1-aleksandr.mikhalitsyn@canonical.com> References: <20230316131526.283569-1-aleksandr.mikhalitsyn@canonical.com> MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Type: text/plain; charset="utf-8" Basic test to check consistency between: - SCM_CREDENTIALS and SCM_PIDFD - SO_PEERCRED and SO_PEERPIDFD 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: linux-kernel@vger.kernel.org Cc: netdev@vger.kernel.org Cc: linux-arch@vger.kernel.org Cc: linux-kselftest@vger.kernel.org Signed-off-by: Alexander Mikhalitsyn Tested-by: Luca Boccassi --- tools/testing/selftests/net/.gitignore | 1 + tools/testing/selftests/net/af_unix/Makefile | 3 +- .../testing/selftests/net/af_unix/scm_pidfd.c | 336 ++++++++++++++++++ 3 files changed, 339 insertions(+), 1 deletion(-) create mode 100644 tools/testing/selftests/net/af_unix/scm_pidfd.c diff --git a/tools/testing/selftests/net/.gitignore b/tools/testing/selftes= ts/net/.gitignore index a6911cae368c..f2d23a1df596 100644 --- a/tools/testing/selftests/net/.gitignore +++ b/tools/testing/selftests/net/.gitignore @@ -25,6 +25,7 @@ reuseport_bpf_cpu reuseport_bpf_numa reuseport_dualstack rxtimestamp +scm_pidfd sk_bind_sendto_listen sk_connect_zero_addr socket diff --git a/tools/testing/selftests/net/af_unix/Makefile b/tools/testing/s= elftests/net/af_unix/Makefile index 1e4b397cece6..221c387a7d7f 100644 --- a/tools/testing/selftests/net/af_unix/Makefile +++ b/tools/testing/selftests/net/af_unix/Makefile @@ -1,3 +1,4 @@ -TEST_GEN_PROGS :=3D diag_uid test_unix_oob unix_connect +CFLAGS +=3D $(KHDR_INCLUDES) +TEST_GEN_PROGS :=3D diag_uid test_unix_oob unix_connect scm_pidfd =20 include ../../lib.mk diff --git a/tools/testing/selftests/net/af_unix/scm_pidfd.c b/tools/testin= g/selftests/net/af_unix/scm_pidfd.c new file mode 100644 index 000000000000..fa502510ee9e --- /dev/null +++ b/tools/testing/selftests/net/af_unix/scm_pidfd.c @@ -0,0 +1,336 @@ +// SPDX-License-Identifier: GPL-2.0 +#define _GNU_SOURCE +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include + +#define clean_errno() (errno =3D=3D 0 ? "None" : strerror(errno)) +#define log_err(MSG, ...) = \ + fprintf(stderr, "(%s:%d: errno: %s) " MSG "\n", __FILE__, __LINE__, \ + clean_errno(), ##__VA_ARGS__) + +#ifndef SCM_PIDFD +#define SCM_PIDFD 0x04 +#endif + +static pid_t client_pid; +static char sock_name[32]; + +static void die(int status) +{ + unlink(sock_name); + kill(client_pid, SIGTERM); + exit(status); +} + +static void child_die() +{ + kill(getppid(), SIGTERM); + exit(1); +} + +static int safe_int(const char *numstr, int *converted) +{ + char *err =3D NULL; + long sli; + + errno =3D 0; + sli =3D strtol(numstr, &err, 0); + if (errno =3D=3D ERANGE && (sli =3D=3D LONG_MAX || sli =3D=3D LONG_MIN)) + return -ERANGE; + + if (errno !=3D 0 && sli =3D=3D 0) + return -EINVAL; + + if (err =3D=3D numstr || *err !=3D '\0') + return -EINVAL; + + if (sli > INT_MAX || sli < INT_MIN) + return -ERANGE; + + *converted =3D (int)sli; + return 0; +} + +static int char_left_gc(const char *buffer, size_t len) +{ + size_t i; + + for (i =3D 0; i < len; i++) { + if (buffer[i] =3D=3D ' ' || buffer[i] =3D=3D '\t') + continue; + + return i; + } + + return 0; +} + +static int char_right_gc(const char *buffer, size_t len) +{ + int i; + + for (i =3D len - 1; i >=3D 0; i--) { + if (buffer[i] =3D=3D ' ' || buffer[i] =3D=3D '\t' || + buffer[i] =3D=3D '\n' || buffer[i] =3D=3D '\0') + continue; + + return i + 1; + } + + return 0; +} + +static char *trim_whitespace_in_place(char *buffer) +{ + buffer +=3D char_left_gc(buffer, strlen(buffer)); + buffer[char_right_gc(buffer, strlen(buffer))] =3D '\0'; + return buffer; +} + +/* borrowed (with all helpers) from pidfd/pidfd_open_test.c */ +static pid_t get_pid_from_fdinfo_file(int pidfd, const char *key, size_t k= eylen) +{ + int ret; + char path[512]; + FILE *f; + size_t n =3D 0; + pid_t result =3D -1; + char *line =3D NULL; + + snprintf(path, sizeof(path), "/proc/self/fdinfo/%d", pidfd); + + f =3D fopen(path, "re"); + if (!f) + return -1; + + while (getline(&line, &n, f) !=3D -1) { + char *numstr; + + if (strncmp(line, key, keylen)) + continue; + + numstr =3D trim_whitespace_in_place(line + 4); + ret =3D safe_int(numstr, &result); + if (ret < 0) + goto out; + + break; + } + +out: + free(line); + fclose(f); + return result; +} + +static int cmsg_check(int fd) +{ + struct msghdr msg =3D { 0 }; + struct cmsghdr *cmsg; + struct iovec iov; + struct ucred *ucred =3D NULL; + int data =3D 0; + char control[CMSG_SPACE(sizeof(struct ucred)) + + CMSG_SPACE(sizeof(int))] =3D { 0 }; + int *pidfd =3D NULL; + pid_t parent_pid; + int err; + + iov.iov_base =3D &data; + iov.iov_len =3D sizeof(data); + + msg.msg_iov =3D &iov; + msg.msg_iovlen =3D 1; + msg.msg_control =3D control; + msg.msg_controllen =3D sizeof(control); + + err =3D recvmsg(fd, &msg, 0); + if (err < 0) { + log_err("recvmsg"); + return 1; + } + + if (msg.msg_flags & (MSG_TRUNC | MSG_CTRUNC)) { + log_err("recvmsg: truncated"); + return 1; + } + + for (cmsg =3D CMSG_FIRSTHDR(&msg); cmsg !=3D NULL; + cmsg =3D CMSG_NXTHDR(&msg, cmsg)) { + if (cmsg->cmsg_level =3D=3D SOL_SOCKET && + cmsg->cmsg_type =3D=3D SCM_PIDFD) { + if (cmsg->cmsg_len < sizeof(*pidfd)) { + log_err("CMSG parse: SCM_PIDFD wrong len"); + return 1; + } + + pidfd =3D (void *)CMSG_DATA(cmsg); + } + + if (cmsg->cmsg_level =3D=3D SOL_SOCKET && + cmsg->cmsg_type =3D=3D SCM_CREDENTIALS) { + if (cmsg->cmsg_len < sizeof(*ucred)) { + log_err("CMSG parse: SCM_CREDENTIALS wrong len"); + return 1; + } + + ucred =3D (void *)CMSG_DATA(cmsg); + } + } + + /* send(pfd, "x", sizeof(char), 0) */ + if (data !=3D 'x') { + log_err("recvmsg: data corruption"); + return 1; + } + + if (!pidfd) { + log_err("CMSG parse: SCM_PIDFD not found"); + return 1; + } + + if (!ucred) { + log_err("CMSG parse: SCM_CREDENTIALS not found"); + return 1; + } + + /* pidfd from SCM_PIDFD should point to the parent process PID */ + parent_pid =3D + get_pid_from_fdinfo_file(*pidfd, "Pid:", sizeof("Pid:") - 1); + if (parent_pid !=3D getppid()) { + log_err("wrong SCM_PIDFD %d !=3D %d", parent_pid, getppid()); + return 1; + } + + return 0; +} + +void client(struct sockaddr_un *listen_addr) +{ + int cfd; + socklen_t len; + struct ucred peer_cred; + int peer_pidfd; + pid_t peer_pid; + int on =3D 0; + + cfd =3D socket(AF_UNIX, SOCK_STREAM, 0); + if (cfd < 0) { + log_err("socket"); + child_die(); + } + + if (connect(cfd, (struct sockaddr *)listen_addr, + sizeof(*listen_addr)) !=3D 0) { + log_err("connect"); + child_die(); + } + + on =3D 1; + if (setsockopt(cfd, SOL_SOCKET, SO_PASSCRED, &on, sizeof(on))) { + log_err("Failed to set SO_PASSCRED"); + child_die(); + } + + if (setsockopt(cfd, SOL_SOCKET, SO_PASSPIDFD, &on, sizeof(on))) { + log_err("Failed to set SO_PASSPIDFD"); + child_die(); + } + + if (cmsg_check(cfd)) { + log_err("cmsg_check failed"); + child_die(); + } + + len =3D sizeof(peer_cred); + if (getsockopt(cfd, SOL_SOCKET, SO_PEERCRED, &peer_cred, &len)) { + log_err("Failed to get SO_PEERCRED"); + child_die(); + } + + len =3D sizeof(peer_pidfd); + if (getsockopt(cfd, SOL_SOCKET, SO_PEERPIDFD, &peer_pidfd, &len)) { + log_err("Failed to get SO_PEERPIDFD"); + child_die(); + } + + /* pid from SO_PEERCRED should point to the parent process PID */ + if (peer_cred.pid !=3D getppid()) { + log_err("Failed to get SO_PEERPIDFD"); + child_die(); + } + + peer_pid =3D get_pid_from_fdinfo_file(peer_pidfd, + "Pid:", sizeof("Pid:") - 1); + if (peer_pid !=3D peer_cred.pid) { + log_err("Failed to get SO_PEERPIDFD"); + child_die(); + } +} + +int main(int argc, char **argv) +{ + int lfd, pfd; + int child_status =3D 0; + struct sockaddr_un listen_addr; + + lfd =3D socket(AF_UNIX, SOCK_STREAM, 0); + if (lfd < 0) { + perror("socket"); + exit(1); + } + + memset(&listen_addr, 0, sizeof(listen_addr)); + listen_addr.sun_family =3D AF_UNIX; + sprintf(sock_name, "scm_pidfd_%d", getpid()); + unlink(sock_name); + strcpy(listen_addr.sun_path, sock_name); + + if ((bind(lfd, (struct sockaddr *)&listen_addr, sizeof(listen_addr))) != =3D + 0) { + perror("socket bind failed"); + exit(1); + } + + if (listen(lfd, 1) < 0) { + perror("listen"); + exit(1); + } + + client_pid =3D fork(); + if (client_pid < 0) { + perror("fork"); + exit(1); + } + + if (client_pid =3D=3D 0) { + client(&listen_addr); + exit(0); + } + + pfd =3D accept(lfd, NULL, NULL); + if (pfd < 0) { + perror("accept"); + die(1); + } + + if (send(pfd, "x", sizeof(char), 0) < 0) { + perror("send"); + die(1); + } + + waitpid(client_pid, &child_status, 0); + die(WIFEXITED(child_status) ? WEXITSTATUS(child_status) : 1); + die(0); +} \ No newline at end of file --=20 2.34.1