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([95.91.208.118]) by smtp.gmail.com with ESMTPSA id et22-20020a170907295600b0094a966330fdsm976806ejc.211.2023.04.13.06.34.38 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 13 Apr 2023 06:34:38 -0700 (PDT) From: Alexander Mikhalitsyn To: davem@davemloft.net Cc: linux-kernel@vger.kernel.org, netdev@vger.kernel.org, daniel@iogearbox.net, Alexander Mikhalitsyn , Eric Dumazet , Jakub Kicinski , Paolo Abeni , Leon Romanovsky , David Ahern , Arnd Bergmann , Kees Cook , Christian Brauner , Kuniyuki Iwashima , Lennart Poettering , Luca Boccassi , linux-arch@vger.kernel.org Subject: [PATCH net-next v4 3/4] net: core: add getsockopt SO_PEERPIDFD Date: Thu, 13 Apr 2023 15:33:54 +0200 Message-Id: <20230413133355.350571-4-aleksandr.mikhalitsyn@canonical.com> X-Mailer: git-send-email 2.34.1 In-Reply-To: <20230413133355.350571-1-aleksandr.mikhalitsyn@canonical.com> References: <20230413133355.350571-1-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: 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 Reviewed-by: Christian Brauner --- v4: - return -ESRCH if sk->sk_peer_pid is NULL from getsockopt() syscall - return errors from pidfd_prepare() as it is from getsockopt() syscall 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 =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..49531c0dc57f 100644 --- a/net/core/sock.c +++ b/net/core/sock.c @@ -1763,6 +1763,39 @@ int sk_getsockopt(struct sock *sk, int level, int op= tname, goto lenout; } =20 + case SO_PEERPIDFD: + { + struct pid *peer_pid; + struct file *pidfd_file =3D NULL; + 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) + return -ESRCH; + + pidfd =3D 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))) { + put_unused_fd(pidfd); + fput(pidfd_file); + + return -EFAULT; + } + + 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 optna= me) default: return false; } + } else if (level =3D=3D SOL_SOCKET) { + switch (optname) { + case SO_PEERPIDFD: + return true; + default: + return false; + } } =20 return false; 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