From fa1c47af4ff641cf9197ecdb1f8240cbb30389c1 Mon Sep 17 00:00:00 2001 From: Namjae Jeon Date: Tue, 5 Aug 2025 18:13:13 +0900 Subject: [PATCH] ksmbd: limit repeated connections from clients with the same IP commit e6bb9193974059ddbb0ce7763fa3882bd60d4dc3 upstream. Repeated connections from clients with the same IP address may exhaust the max connections and prevent other normal client connections. This patch limit repeated connections from clients with the same IP. Reported-by: tianshuo han Cc: stable@vger.kernel.org Signed-off-by: Namjae Jeon Signed-off-by: Steve French Signed-off-by: Greg Kroah-Hartman --- fs/smb/server/connection.h | 1 + fs/smb/server/transport_tcp.c | 17 +++++++++++++++++ 2 files changed, 18 insertions(+) diff --git a/fs/smb/server/connection.h b/fs/smb/server/connection.h index 47e6a8694c0fc..c769fe3859b37 100644 --- a/fs/smb/server/connection.h +++ b/fs/smb/server/connection.h @@ -45,6 +45,7 @@ struct ksmbd_conn { struct mutex srv_mutex; int status; unsigned int cli_cap; + __be32 inet_addr; char *request_buf; struct ksmbd_transport *transport; struct nls_table *local_nls; diff --git a/fs/smb/server/transport_tcp.c b/fs/smb/server/transport_tcp.c index 64941a49438f3..e86bc4a460687 100644 --- a/fs/smb/server/transport_tcp.c +++ b/fs/smb/server/transport_tcp.c @@ -87,6 +87,7 @@ static struct tcp_transport *alloc_transport(struct socket *client_sk) return NULL; } + conn->inet_addr = inet_sk(client_sk->sk)->inet_daddr; conn->transport = KSMBD_TRANS(t); KSMBD_TRANS(t)->conn = conn; KSMBD_TRANS(t)->ops = &ksmbd_tcp_transport_ops; @@ -230,6 +231,8 @@ static int ksmbd_kthread_fn(void *p) { struct socket *client_sk = NULL; struct interface *iface = (struct interface *)p; + struct inet_sock *csk_inet; + struct ksmbd_conn *conn; int ret; while (!kthread_should_stop()) { @@ -248,6 +251,20 @@ static int ksmbd_kthread_fn(void *p) continue; } + /* + * Limits repeated connections from clients with the same IP. + */ + csk_inet = inet_sk(client_sk->sk); + down_read(&conn_list_lock); + list_for_each_entry(conn, &conn_list, conns_list) + if (csk_inet->inet_daddr == conn->inet_addr) { + ret = -EAGAIN; + break; + } + up_read(&conn_list_lock); + if (ret == -EAGAIN) + 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", -- 2.47.3