From: Namjae Jeon linkinjeon@kernel.org
commit 0d0d4680db22eda1eea785c47bbf66a9b33a8b16 upstream.
Add max connections parameter to limit number of maximum simultaneous connections.
Fixes: 0626e6641f6b ("cifsd: add server handler for central processing and tranport layers") Cc: stable@vger.kernel.org Reviewed-by: Sergey Senozhatsky senozhatsky@chromium.org Signed-off-by: Namjae Jeon linkinjeon@kernel.org Signed-off-by: Steve French stfrench@microsoft.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- fs/ksmbd/ksmbd_netlink.h | 3 ++- fs/ksmbd/server.h | 1 + fs/ksmbd/transport_ipc.c | 3 +++ fs/ksmbd/transport_tcp.c | 17 ++++++++++++++++- 4 files changed, 22 insertions(+), 2 deletions(-)
--- a/fs/ksmbd/ksmbd_netlink.h +++ b/fs/ksmbd/ksmbd_netlink.h @@ -105,7 +105,8 @@ struct ksmbd_startup_request { __u32 sub_auth[3]; /* Subauth value for Security ID */ __u32 smb2_max_credits; /* MAX credits */ __u32 smbd_max_io_size; /* smbd read write size */ - __u32 reserved[127]; /* Reserved room */ + __u32 max_connections; /* Number of maximum simultaneous connections */ + __u32 reserved[126]; /* Reserved room */ __u32 ifc_list_sz; /* interfaces list size */ __s8 ____payload[]; }; --- a/fs/ksmbd/server.h +++ b/fs/ksmbd/server.h @@ -41,6 +41,7 @@ struct ksmbd_server_config { unsigned int share_fake_fscaps; struct smb_sid domain_sid; unsigned int auth_mechs; + unsigned int max_connections;
char *conf[SERVER_CONF_WORK_GROUP + 1]; }; --- a/fs/ksmbd/transport_ipc.c +++ b/fs/ksmbd/transport_ipc.c @@ -307,6 +307,9 @@ static int ipc_server_config_on_startup( if (req->smbd_max_io_size) init_smbd_max_io_size(req->smbd_max_io_size);
+ if (req->max_connections) + server_conf.max_connections = req->max_connections; + ret = ksmbd_set_netbios_name(req->netbios_name); ret |= ksmbd_set_server_string(req->server_string); ret |= ksmbd_set_work_group(req->work_group); --- a/fs/ksmbd/transport_tcp.c +++ b/fs/ksmbd/transport_tcp.c @@ -15,6 +15,8 @@ #define IFACE_STATE_DOWN BIT(0) #define IFACE_STATE_CONFIGURED BIT(1)
+static atomic_t active_num_conn; + struct interface { struct task_struct *ksmbd_kthread; struct socket *ksmbd_socket; @@ -185,8 +187,10 @@ static int ksmbd_tcp_new_connection(stru struct tcp_transport *t;
t = alloc_transport(client_sk); - if (!t) + if (!t) { + sock_release(client_sk); return -ENOMEM; + }
csin = KSMBD_TCP_PEER_SOCKADDR(KSMBD_TRANS(t)->conn); if (kernel_getpeername(client_sk, csin) < 0) { @@ -239,6 +243,15 @@ static int ksmbd_kthread_fn(void *p) continue; }
+ if (server_conf.max_connections && + atomic_inc_return(&active_num_conn) >= server_conf.max_connections) { + pr_info_ratelimited("Limit the maximum number of connections(%u)\n", + atomic_read(&active_num_conn)); + atomic_dec(&active_num_conn); + sock_release(client_sk); + continue; + } + ksmbd_debug(CONN, "connect success: accepted new connection\n"); client_sk->sk->sk_rcvtimeo = KSMBD_TCP_RECV_TIMEOUT; client_sk->sk->sk_sndtimeo = KSMBD_TCP_SEND_TIMEOUT; @@ -368,6 +381,8 @@ static int ksmbd_tcp_writev(struct ksmbd static void ksmbd_tcp_disconnect(struct ksmbd_transport *t) { free_transport(TCP_TRANS(t)); + if (server_conf.max_connections) + atomic_dec(&active_num_conn); }
static void tcp_destroy_socket(struct socket *ksmbd_socket)