From d2f77c53342e3e13ce1fd7f9638ee200026e14f4 Mon Sep 17 00:00:00 2001 From: Paolo Abeni Date: Mon, 29 Jun 2020 22:26:22 +0200 Subject: [PATCH] mptcp: check for plain TCP sock at accept time This cleanup the code a bit and avoid corrupted states on weird syscall sequence (accept(), connect()). Signed-off-by: Paolo Abeni Signed-off-by: Davide Caratti Reviewed-by: Mat Martineau Signed-off-by: David S. Miller --- net/mptcp/protocol.c | 69 +++++--------------------------------------- 1 file changed, 7 insertions(+), 62 deletions(-) diff --git a/net/mptcp/protocol.c b/net/mptcp/protocol.c index 84ae96be9837..dbeb6fe374f5 100644 --- a/net/mptcp/protocol.c +++ b/net/mptcp/protocol.c @@ -52,13 +52,10 @@ static struct socket *__mptcp_nmpc_socket(const struct mptcp_sock *msk) return msk->subflow; } -static struct socket *mptcp_is_tcpsk(struct sock *sk) +static bool mptcp_is_tcpsk(struct sock *sk) { struct socket *sock = sk->sk_socket; - if (sock->sk != sk) - return NULL; - if (unlikely(sk->sk_prot == &tcp_prot)) { /* we are being invoked after mptcp_accept() has * accepted a non-mp-capable flow: sk is a tcp_sk, @@ -68,27 +65,21 @@ static struct socket *mptcp_is_tcpsk(struct sock *sk) * bypass mptcp. */ sock->ops = &inet_stream_ops; - return sock; + return true; #if IS_ENABLED(CONFIG_MPTCP_IPV6) } else if (unlikely(sk->sk_prot == &tcpv6_prot)) { sock->ops = &inet6_stream_ops; - return sock; + return true; #endif } - return NULL; + return false; } static struct socket *__mptcp_tcp_fallback(struct mptcp_sock *msk) { - struct socket *sock; - sock_owned_by_me((const struct sock *)msk); - sock = mptcp_is_tcpsk((struct sock *)msk); - if (unlikely(sock)) - return sock; - if (likely(!__mptcp_check_fallback(msk))) return NULL; @@ -1466,7 +1457,6 @@ static struct sock *mptcp_accept(struct sock *sk, int flags, int *err, return NULL; pr_debug("msk=%p, subflow is mptcp=%d", msk, sk_is_mptcp(newsk)); - if (sk_is_mptcp(newsk)) { struct mptcp_subflow_context *subflow; struct sock *new_mptcp_sock; @@ -1821,42 +1811,6 @@ unlock: return err; } -static int mptcp_v4_getname(struct socket *sock, struct sockaddr *uaddr, - int peer) -{ - if (sock->sk->sk_prot == &tcp_prot) { - /* we are being invoked from __sys_accept4, after - * mptcp_accept() has just accepted a non-mp-capable - * flow: sk is a tcp_sk, not an mptcp one. - * - * Hand the socket over to tcp so all further socket ops - * bypass mptcp. - */ - sock->ops = &inet_stream_ops; - } - - return inet_getname(sock, uaddr, peer); -} - -#if IS_ENABLED(CONFIG_MPTCP_IPV6) -static int mptcp_v6_getname(struct socket *sock, struct sockaddr *uaddr, - int peer) -{ - if (sock->sk->sk_prot == &tcpv6_prot) { - /* we are being invoked from __sys_accept4 after - * mptcp_accept() has accepted a non-mp-capable - * subflow: sk is a tcp_sk, not mptcp. - * - * Hand the socket over to tcp so all further - * socket ops bypass mptcp. - */ - sock->ops = &inet6_stream_ops; - } - - return inet6_getname(sock, uaddr, peer); -} -#endif - static int mptcp_listen(struct socket *sock, int backlog) { struct mptcp_sock *msk = mptcp_sk(sock->sk); @@ -1885,15 +1839,6 @@ unlock: return err; } -static bool is_tcp_proto(const struct proto *p) -{ -#if IS_ENABLED(CONFIG_MPTCP_IPV6) - return p == &tcp_prot || p == &tcpv6_prot; -#else - return p == &tcp_prot; -#endif -} - static int mptcp_stream_accept(struct socket *sock, struct socket *newsock, int flags, bool kern) { @@ -1915,7 +1860,7 @@ static int mptcp_stream_accept(struct socket *sock, struct socket *newsock, release_sock(sock->sk); err = ssock->ops->accept(sock, newsock, flags, kern); - if (err == 0 && !is_tcp_proto(newsock->sk->sk_prot)) { + if (err == 0 && !mptcp_is_tcpsk(newsock->sk)) { struct mptcp_sock *msk = mptcp_sk(newsock->sk); struct mptcp_subflow_context *subflow; @@ -2011,7 +1956,7 @@ static const struct proto_ops mptcp_stream_ops = { .connect = mptcp_stream_connect, .socketpair = sock_no_socketpair, .accept = mptcp_stream_accept, - .getname = mptcp_v4_getname, + .getname = inet_getname, .poll = mptcp_poll, .ioctl = inet_ioctl, .gettstamp = sock_gettstamp, @@ -2065,7 +2010,7 @@ static const struct proto_ops mptcp_v6_stream_ops = { .connect = mptcp_stream_connect, .socketpair = sock_no_socketpair, .accept = mptcp_stream_accept, - .getname = mptcp_v6_getname, + .getname = inet6_getname, .poll = mptcp_poll, .ioctl = inet6_ioctl, .gettstamp = sock_gettstamp,