From 5e2ff6704a275be009be8979af17c52361b79b89 Mon Sep 17 00:00:00 2001 From: Alexander Mikhalitsyn Date: Thu, 8 Jun 2023 22:26:25 +0200 Subject: scm: add SO_PASSPIDFD and SCM_PIDFD 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. We mask SO_PASSPIDFD feature if CONFIG_UNIX is not builtin because it depends on a pidfd_prepare() API which is not exported to the kernel modules. Idea comes from UAPI kernel group: https://uapi-group.org/kernel-features/ Big thanks to Christian Brauner and Lennart Poettering for productive discussions about this. 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 Reviewed-by: Kuniyuki Iwashima Reviewed-by: Christian Brauner Signed-off-by: Alexander Mikhalitsyn Reviewed-by: Eric Dumazet Signed-off-by: David S. Miller --- include/linux/socket.h | 1 + 1 file changed, 1 insertion(+) (limited to 'include/linux/socket.h') diff --git a/include/linux/socket.h b/include/linux/socket.h index 3fd3436bc09f..58204700018a 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) */ struct ucred { __u32 pid; -- cgit v1.2.3