The patch below does not apply to the 6.1-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to stable@vger.kernel.org.

To reproduce the conflict and resubmit, you may use the following commands:

git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-6.1.y git checkout FETCH_HEAD git cherry-pick -x d8b6dc9256762293048bf122fc11c4e612d0ef5d # <resolve conflicts, build, test, etc.> git commit -s git send-email --to 'stable@vger.kernel.org' --in-reply-to '2025101339-chunk-hassle-3d8e@gregkh' --subject-prefix 'PATCH 6.1.y' HEAD^..

Possible dependencies:

thanks,

greg k-h

------------------ original commit in Linus's tree ------------------

From d8b6dc9256762293048bf122fc11c4e612d0ef5d Mon Sep 17 00:00:00 2001 From: Namjae Jeon linkinjeon@kernel.org Date: Wed, 1 Oct 2025 09:25:35 +0900 Subject: [PATCH] ksmbd: add max ip connections parameter

This parameter set the maximum number of connections per ip address. The default is 8.

Cc: stable@vger.kernel.org Fixes: c0d41112f1a5 ("ksmbd: extend the connection limiting mechanism to support IPv6") Signed-off-by: Namjae Jeon linkinjeon@kernel.org Signed-off-by: Steve French stfrench@microsoft.com

diff --git a/fs/smb/server/ksmbd_netlink.h b/fs/smb/server/ksmbd_netlink.h index 3f07a612c05b..8ccd57fd904b 100644 --- a/fs/smb/server/ksmbd_netlink.h +++ b/fs/smb/server/ksmbd_netlink.h @@ -112,10 +112,11 @@ struct ksmbd_startup_request { __u32 smbd_max_io_size; /* smbd read write size */ __u32 max_connections; /* Number of maximum simultaneous connections */ __s8 bind_interfaces_only; - __s8 reserved[503]; /* Reserved room */ + __u32 max_ip_connections; /* Number of maximum connection per ip address */ + __s8 reserved[499]; /* Reserved room */ __u32 ifc_list_sz; /* interfaces list size */ __s8 ____payload[]; -}; +} __packed;

#define KSMBD_STARTUP_CONFIG_INTERFACES(s) ((s)->____payload)

diff --git a/fs/smb/server/server.h b/fs/smb/server/server.h index 995555febe7d..b8a7317be86b 100644 --- a/fs/smb/server/server.h +++ b/fs/smb/server/server.h @@ -43,6 +43,7 @@ struct ksmbd_server_config { unsigned int auth_mechs; unsigned int max_connections; unsigned int max_inflight_req; + unsigned int max_ip_connections;

char *conf[SERVER_CONF_WORK_GROUP + 1]; struct task_struct *dh_task; diff --git a/fs/smb/server/transport_ipc.c b/fs/smb/server/transport_ipc.c index 2a3e2b0ce557..2aa1b29bea08 100644 --- a/fs/smb/server/transport_ipc.c +++ b/fs/smb/server/transport_ipc.c @@ -335,6 +335,9 @@ static int ipc_server_config_on_startup(struct ksmbd_startup_request *req) if (req->max_connections) server_conf.max_connections = req->max_connections;

+ if (req->max_ip_connections) + server_conf.max_ip_connections = req->max_ip_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); diff --git a/fs/smb/server/transport_tcp.c b/fs/smb/server/transport_tcp.c index 7440a2fd1126..e9ecb43db9d9 100644 --- a/fs/smb/server/transport_tcp.c +++ b/fs/smb/server/transport_tcp.c @@ -225,6 +225,7 @@ static int ksmbd_kthread_fn(void *p) struct interface *iface = (struct interface *)p; struct ksmbd_conn *conn; int ret; + unsigned int max_ip_conns;

while (!kthread_should_stop()) { mutex_lock(&iface->sock_release_lock); @@ -242,34 +243,38 @@ static int ksmbd_kthread_fn(void *p) continue; }

+ if (!server_conf.max_ip_connections) + goto skip_max_ip_conns_limit; + /* * Limits repeated connections from clients with the same IP. */ + max_ip_conns = 0; down_read(&conn_list_lock); - list_for_each_entry(conn, &conn_list, conns_list) + list_for_each_entry(conn, &conn_list, conns_list) { #if IS_ENABLED(CONFIG_IPV6) if (client_sk->sk->sk_family == AF_INET6) { if (memcmp(&client_sk->sk->sk_v6_daddr, - &conn->inet6_addr, 16) == 0) { - ret = -EAGAIN; - break; - } + &conn->inet6_addr, 16) == 0) + max_ip_conns++; } else if (inet_sk(client_sk->sk)->inet_daddr == - conn->inet_addr) { - ret = -EAGAIN; - break; - } + conn->inet_addr) + max_ip_conns++; #else if (inet_sk(client_sk->sk)->inet_daddr == - conn->inet_addr) { + conn->inet_addr) + max_ip_conns++; +#endif + if (server_conf.max_ip_connections <= max_ip_conns) { ret = -EAGAIN; break; } -#endif + } up_read(&conn_list_lock); if (ret == -EAGAIN) continue;

+skip_max_ip_conns_limit: 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",