6.1-stable review patch. If anyone has any objections, please let me know.
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From: Namjae Jeon linkinjeon@kernel.org
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 hantianshuo233@gmail.com Cc: stable@vger.kernel.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/smb/server/connection.h | 1 + fs/smb/server/transport_tcp.c | 17 +++++++++++++++++ 2 files changed, 18 insertions(+)
--- 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; --- a/fs/smb/server/transport_tcp.c +++ b/fs/smb/server/transport_tcp.c @@ -87,6 +87,7 @@ static struct tcp_transport *alloc_trans 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; @@ -226,6 +227,8 @@ 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()) { @@ -244,6 +247,20 @@ 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",