From: Paolo Abeni pabeni@redhat.com
[ Upstream commit ad2171009d968104ccda9dc517f5a3ba891515db ]
For consistency, in mptcp_pm_nl_create_listen_socket(), we need to call the __mptcp_nmpc_socket() under the msk socket lock.
Note that as a side effect, mptcp_subflow_create_socket() needs a 'nested' lockdep annotation, as it will acquire the subflow (kernel) socket lock under the in-kernel listener msk socket lock.
The current lack of locking is almost harmless, because the relevant socket is not exposed to the user space, but in future we will add more complexity to the mentioned helper, let's play safe.
Fixes: 1729cf186d8a ("mptcp: create the listening socket for new port") Cc: stable@vger.kernel.org Signed-off-by: Paolo Abeni pabeni@redhat.com Reviewed-by: Matthieu Baerts matthieu.baerts@tessares.net Signed-off-by: Matthieu Baerts matthieu.baerts@tessares.net Signed-off-by: David S. Miller davem@davemloft.net Signed-off-by: Matthieu Baerts matthieu.baerts@tessares.net --- net/mptcp/pm_netlink.c | 10 ++++++---- net/mptcp/subflow.c | 2 +- 2 files changed, 7 insertions(+), 5 deletions(-)
diff --git a/net/mptcp/pm_netlink.c b/net/mptcp/pm_netlink.c index 9813ed0fde9b..15253afc3fff 100644 --- a/net/mptcp/pm_netlink.c +++ b/net/mptcp/pm_netlink.c @@ -992,8 +992,8 @@ static int mptcp_pm_nl_create_listen_socket(struct sock *sk, { int addrlen = sizeof(struct sockaddr_in); struct sockaddr_storage addr; - struct mptcp_sock *msk; struct socket *ssock; + struct sock *newsk; int backlog = 1024; int err;
@@ -1002,13 +1002,15 @@ static int mptcp_pm_nl_create_listen_socket(struct sock *sk, if (err) return err;
- msk = mptcp_sk(entry->lsk->sk); - if (!msk) { + newsk = entry->lsk->sk; + if (!newsk) { err = -EINVAL; goto out; }
- ssock = __mptcp_nmpc_socket(msk); + lock_sock(newsk); + ssock = __mptcp_nmpc_socket(mptcp_sk(newsk)); + release_sock(newsk); if (!ssock) { err = -EINVAL; goto out; diff --git a/net/mptcp/subflow.c b/net/mptcp/subflow.c index 929b0ee8b3d5..c4971bc42f60 100644 --- a/net/mptcp/subflow.c +++ b/net/mptcp/subflow.c @@ -1631,7 +1631,7 @@ int mptcp_subflow_create_socket(struct sock *sk, unsigned short family, if (err) return err;
- lock_sock(sf->sk); + lock_sock_nested(sf->sk, SINGLE_DEPTH_NESTING);
/* the newly created socket has to be in the same cgroup as its parent */ mptcp_attach_cgroup(sk, sf->sk);