From 7d14b0d2b9b317cfc14161143e2006b95a5da9b1 Mon Sep 17 00:00:00 2001 From: Paolo Abeni Date: Thu, 7 May 2020 18:53:24 +0200 Subject: [PATCH] mptcp: set correct vfs info for subflows When a subflow is created via mptcp_subflow_create_socket(), a new 'struct socket' is allocated, with a new i_ino value. When inspecting TCP sockets via the procfs and or the diag interface, the above ones are not related to the process owning the MPTCP master socket, even if they are a logical part of it ('ss -p' shows an empty process field) Additionally, subflows created by the path manager get the uid/gid from the running workqueue. Subflows are part of the owning MPTCP master socket, let's adjust the vfs info to reflect this. After this patch, 'ss' correctly displays subflows as belonging to the msk socket creator. Fixes: 2303f994b3e1 ("mptcp: Associate MPTCP context with TCP socket") Signed-off-by: Paolo Abeni Signed-off-by: David S. Miller --- net/mptcp/subflow.c | 10 ++++++++++ 1 file changed, 10 insertions(+) diff --git a/net/mptcp/subflow.c b/net/mptcp/subflow.c index 67a4e35d4838..4931a29a6f08 100644 --- a/net/mptcp/subflow.c +++ b/net/mptcp/subflow.c @@ -1012,6 +1012,16 @@ int mptcp_subflow_create_socket(struct sock *sk, struct socket **new_sock) if (err) return err; + /* the newly created socket really belongs to the owning MPTCP master + * socket, even if for additional subflows the allocation is performed + * by a kernel workqueue. Adjust inode references, so that the + * procfs/diag interaces really show this one belonging to the correct + * user. + */ + SOCK_INODE(sf)->i_ino = SOCK_INODE(sk->sk_socket)->i_ino; + SOCK_INODE(sf)->i_uid = SOCK_INODE(sk->sk_socket)->i_uid; + SOCK_INODE(sf)->i_gid = SOCK_INODE(sk->sk_socket)->i_gid; + subflow = mptcp_subflow_ctx(sf->sk); pr_debug("subflow=%p", subflow);