Commit 7d14b0d2 authored May 07, 2020 by Paolo Abeni Committed by David S. Miller May 07, 2020

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: 2303f994 ("mptcp: Associate MPTCP context with TCP socket")
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

parent ff8ce319

net/mptcp/subflow.c

+10 −0

Original line number	Diff line number	Diff line
		@@ -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);

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