From: Paolo Abeni pabeni@redhat.com
commit c0bf3c6aa444a5ef44acc57ef6cfa53fd4fc1c9b upstream.
If the mptcp socket creation fails due to a CGROUP_INET_SOCK_CREATE eBPF program, the MPTCP protocol ends-up leaking all the subflows: the related cleanup happens in __mptcp_destroy_sock() that is not invoked in such code path.
Address the issue moving the subflow sockets cleanup in the mptcp_destroy_common() helper, which is invoked in every msk cleanup path.
Additionally get rid of the intermediate list_splice_init step, which is an unneeded relic from the past.
The issue is present since before the reported root cause commit, but any attempt to backport the fix before that hash will require a complete rewrite.
Fixes: e16163b6e2 ("mptcp: refactor shutdown and close") Reported-by: Nguyen Dinh Phi phind.uet@gmail.com Reviewed-by: Mat Martineau mathew.j.martineau@linux.intel.com Co-developed-by: Nguyen Dinh Phi phind.uet@gmail.com Signed-off-by: Nguyen Dinh Phi phind.uet@gmail.com Signed-off-by: Paolo Abeni pabeni@redhat.com Signed-off-by: Mat Martineau mathew.j.martineau@linux.intel.com Signed-off-by: David S. Miller davem@davemloft.net Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- net/mptcp/protocol.c | 39 +++++++++++++++------------------------ net/mptcp/protocol.h | 2 +- net/mptcp/subflow.c | 3 ++- 3 files changed, 18 insertions(+), 26 deletions(-)
--- a/net/mptcp/protocol.c +++ b/net/mptcp/protocol.c @@ -2805,30 +2805,16 @@ static void __mptcp_wr_shutdown(struct s
static void __mptcp_destroy_sock(struct sock *sk) { - struct mptcp_subflow_context *subflow, *tmp; struct mptcp_sock *msk = mptcp_sk(sk); - LIST_HEAD(conn_list);
pr_debug("msk=%p", msk);
might_sleep();
- /* join list will be eventually flushed (with rst) at sock lock release time*/ - list_splice_init(&msk->conn_list, &conn_list); - mptcp_stop_timer(sk); sk_stop_timer(sk, &sk->sk_timer); msk->pm.status = 0;
- /* clears msk->subflow, allowing the following loop to close - * even the initial subflow - */ - mptcp_dispose_initial_subflow(msk); - list_for_each_entry_safe(subflow, tmp, &conn_list, node) { - struct sock *ssk = mptcp_subflow_tcp_sock(subflow); - __mptcp_close_ssk(sk, ssk, subflow, 0); - } - sk->sk_prot->destroy(sk);
WARN_ON_ONCE(msk->rmem_fwd_alloc); @@ -2920,24 +2906,20 @@ static void mptcp_copy_inaddrs(struct so
static int mptcp_disconnect(struct sock *sk, int flags) { - struct mptcp_subflow_context *subflow, *tmp; struct mptcp_sock *msk = mptcp_sk(sk);
inet_sk_state_store(sk, TCP_CLOSE);
- list_for_each_entry_safe(subflow, tmp, &msk->conn_list, node) { - struct sock *ssk = mptcp_subflow_tcp_sock(subflow); - - __mptcp_close_ssk(sk, ssk, subflow, MPTCP_CF_FASTCLOSE); - } - mptcp_stop_timer(sk); sk_stop_timer(sk, &sk->sk_timer);
if (mptcp_sk(sk)->token) mptcp_event(MPTCP_EVENT_CLOSED, mptcp_sk(sk), NULL, GFP_KERNEL);
- mptcp_destroy_common(msk); + /* msk->subflow is still intact, the following will not free the first + * subflow + */ + mptcp_destroy_common(msk, MPTCP_CF_FASTCLOSE); msk->last_snd = NULL; WRITE_ONCE(msk->flags, 0); msk->cb_flags = 0; @@ -3087,12 +3069,17 @@ out: return newsk; }
-void mptcp_destroy_common(struct mptcp_sock *msk) +void mptcp_destroy_common(struct mptcp_sock *msk, unsigned int flags) { + struct mptcp_subflow_context *subflow, *tmp; struct sock *sk = (struct sock *)msk;
__mptcp_clear_xmit(sk);
+ /* join list will be eventually flushed (with rst) at sock lock release time */ + list_for_each_entry_safe(subflow, tmp, &msk->conn_list, node) + __mptcp_close_ssk(sk, mptcp_subflow_tcp_sock(subflow), subflow, flags); + /* move to sk_receive_queue, sk_stream_kill_queues will purge it */ mptcp_data_lock(sk); skb_queue_splice_tail_init(&msk->receive_queue, &sk->sk_receive_queue); @@ -3114,7 +3101,11 @@ static void mptcp_destroy(struct sock *s { struct mptcp_sock *msk = mptcp_sk(sk);
- mptcp_destroy_common(msk); + /* clears msk->subflow, allowing the following to close + * even the initial subflow + */ + mptcp_dispose_initial_subflow(msk); + mptcp_destroy_common(msk, 0); sk_sockets_allocated_dec(sk); }
--- a/net/mptcp/protocol.h +++ b/net/mptcp/protocol.h @@ -718,7 +718,7 @@ static inline void mptcp_write_space(str } }
-void mptcp_destroy_common(struct mptcp_sock *msk); +void mptcp_destroy_common(struct mptcp_sock *msk, unsigned int flags);
#define MPTCP_TOKEN_MAX_RETRIES 4
--- a/net/mptcp/subflow.c +++ b/net/mptcp/subflow.c @@ -621,7 +621,8 @@ static void mptcp_sock_destruct(struct s sock_orphan(sk); }
- mptcp_destroy_common(mptcp_sk(sk)); + /* We don't need to clear msk->subflow, as it's still NULL at this point */ + mptcp_destroy_common(mptcp_sk(sk), 0); inet_sock_destruct(sk); }