// SPDX-License-Identifier: GPL-2.0-or-later
/*
* Copyright (C) 2016 Namjae Jeon <[email protected]>
* Copyright (C) 2018 Samsung Electronics Co., Ltd.
*/
#include <linux/freezer.h>
#include "smb_common.h"
#include "server.h"
#include "auth.h"
#include "connection.h"
#include "transport_tcp.h"
#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;
struct list_head entry;
char *name;
struct mutex sock_release_lock;
int state;
};
static LIST_HEAD(iface_list);
static int bind_additional_ifaces;
struct tcp_transport {
struct ksmbd_transport transport;
struct socket *sock;
struct kvec *iov;
unsigned int nr_iov;
};
static const struct ksmbd_transport_ops ksmbd_tcp_transport_ops;
static void tcp_stop_kthread(struct task_struct *kthread);
static struct interface *alloc_iface(char *ifname);
#define KSMBD_TRANS(t) (&(t)->transport)
#define TCP_TRANS(t) ((struct tcp_transport *)container_of(t, \
struct tcp_transport, transport))
static inline void ksmbd_tcp_nodelay(struct socket *sock)
{
tcp_sock_set_nodelay(sock->sk);
}
static inline void ksmbd_tcp_reuseaddr(struct socket *sock)
{
sock_set_reuseaddr(sock->sk);
}
static inline void ksmbd_tcp_rcv_timeout(struct socket *sock, s64 secs)
{
lock_sock(sock->sk);
if (secs && secs < MAX_SCHEDULE_TIMEOUT / HZ - 1)
sock->sk->sk_rcvtimeo = secs * HZ;
else
sock->sk->sk_rcvtimeo = MAX_SCHEDULE_TIMEOUT;
release_sock(sock->sk);
}
static inline void ksmbd_tcp_snd_timeout(struct socket *sock, s64 secs)
{
sock_set_sndtimeo(sock->sk, secs);
}
static struct tcp_transport *alloc_transport(struct socket *client_sk)
{
struct tcp_transport *t;
struct ksmbd_conn *conn;
t = kzalloc(sizeof(*t), GFP_KERNEL);
if (!t)
return NULL;
t->sock = client_sk;
conn = ksmbd_conn_alloc();
if (!conn) {
kfree(t);
return NULL;
}
conn->transport = KSMBD_TRANS(t);
KSMBD_TRANS(t)->conn = conn;
KSMBD_TRANS(t)->ops = &ksmbd_tcp_transport_ops;
return t;
}
static void free_transport(struct tcp_transport *t)
{
kernel_sock_shutdown(t->sock, SHUT_RDWR);
sock_release(t->sock);
t->sock = NULL;
ksmbd_conn_free(KSMBD_TRANS(t)->conn);
kfree(t->iov);
kfree(t);
}
/**
* kvec_array_init() - initialize a IO vector segment
* @new: IO vector to be initialized
* @iov: base IO vector
* @nr_segs: number of segments in base iov
* @bytes: total iovec length so far for read
*
* Return: Number of IO segments
*/
static unsigned int kvec_array_init(struct kvec *new, struct kvec *iov,
unsigned int nr_segs, size_t bytes)
{
size_t base = 0;
while (bytes || !iov->iov_len) {
int copy = min(bytes, iov->iov_len);
bytes -= copy;
base += copy;
if (iov->iov_len == base) {
iov++;
nr_segs--;
base = 0;
}
}
memcpy(new, iov, sizeof(*iov) * nr_segs);
new->iov_base += base;
new->iov_len -= base;
return nr_segs;
}
/**
* get_conn_iovec() - get connection iovec for reading from socket
* @t: TCP transport instance
* @nr_segs: number of segments in iov
*
* Return: return existing or newly allocate iovec
*/
static struct kvec *get_conn_iovec(struct tcp_transport *t, unsigned int nr_segs)
{
struct kvec *new_iov;
if (t->iov && nr_segs <= t->nr_iov)
return t->iov;
/* not big enough -- allocate a new one and release the old */
new_iov = kmalloc_array(nr_segs, sizeof(*new_iov), GFP_KERNEL);
if (new_iov) {
kfree(t->iov);
t->iov = new_iov;
t->nr_iov = nr_segs;
}
return new_iov;
}
static unsigned short ksmbd_tcp_get_port(const struct sockaddr *sa)
{
switch (sa->sa_family) {
case AF_INET:
return ntohs(((struct sockaddr_in *)sa)->sin_port);
case AF_INET6:
return ntohs(((struct sockaddr_in6 *)sa)->sin6_port);
}
return 0;
}
/**
* ksmbd_tcp_new_connection() - create a new tcp session on mount
* @client_sk: socket associated with new connection
*
* whenever a new connection is requested, create a conn thread
* (session thread) to handle new incoming smb requests from the connection
*
* Return: 0 on success, otherwise error
*/
static int ksmbd_tcp_new_connection(struct socket *client_sk)
{
struct sockaddr *csin;
int rc = 0;
struct tcp_transport *t;
struct task_struct *handler;
t = alloc_transport(client_sk);
if (!t) {
sock_release(client_sk);
return -ENOMEM;
}
csin = KSMBD_TCP_PEER_SOCKADDR(KSMBD_TRANS(t)->conn);
if (kernel_getpeername(client_sk, csin) < 0) {
pr_err("client ip resolution failed\n");
rc = -EINVAL;
goto out_error;
}
handler = kthread_run(ksmbd_conn_handler_loop,
KSMBD_TRANS(t)->conn,
"ksmbd:%u",
ksmbd_tcp_get_port(csin));
if (IS_ERR(handler)) {
pr_err("cannot start conn thread\n");
rc = PTR_ERR(handler);
free_transport(t);
}
return rc;
out_error:
free_transport(t);
return rc;
}
/**
* ksmbd_kthread_fn() - listen to new SMB connections and callback server
* @p: arguments to forker thread
*
* Return: 0 on success, error number otherwise
*/
static int ksmbd_kthread_fn(void *p)
{
struct socket *client_sk = NULL;
struct interface *iface = (struct interface *)p;
int ret;
while (!kthread_should_stop()) {
mutex_lock(&iface->sock_release_lock);
if (!iface->ksmbd_socket) {
mutex_unlock(&iface->sock_release_lock);
break;
}
ret = kernel_accept(iface->ksmbd_socket, &client_sk,
SOCK_NONBLOCK);
mutex_unlock(&iface->sock_release_lock);
if (ret) {
if (ret == -EAGAIN)
/* check for new connections every 100 msecs */
schedule_timeout_interruptible(HZ / 10);
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;
ksmbd_tcp_new_connection(client_sk);
}
ksmbd_debug(CONN, "releasing socket\n");
return 0;
}
/**
* ksmbd_tcp_run_kthread() - start forker thread
* @iface: pointer to struct interface
*
* start forker thread(ksmbd/0) at module init time to listen
* on port 445 for new SMB connection requests. It creates per connection
* server threads(ksmbd/x)
*
* Return: 0 on success or error number
*/
static int ksmbd_tcp_run_kthread(struct interface *iface)
{
int rc;
struct task_struct *kthread;
kthread = kthread_run(ksmbd_kthread_fn, (void *)iface, "ksmbd-%s",
iface->name);
if (IS_ERR(kthread)) {
rc = PTR_ERR(kthread);
return rc;
}
iface->ksmbd_kthread = kthread;
return 0;
}
/**
* ksmbd_tcp_readv() - read data from socket in given iovec
* @t: TCP transport instance
* @iov_orig: base IO vector
* @nr_segs: number of segments in base iov
* @to_read: number of bytes to read from socket
* @max_retries: maximum retry count
*
* Return: on success return number of bytes read from socket,
* otherwise return error number
*/
static int ksmbd_tcp_readv(struct tcp_transport *t, struct kvec *iov_orig,
unsigned int nr_segs, unsigned int to_read,
int max_retries)
{
int length = 0;
int total_read;
unsigned int segs;
struct msghdr ksmbd_msg;
struct kvec *iov;
struct ksmbd_conn *conn = KSMBD_TRANS(t)->conn;
iov = get_conn_iovec(t, nr_segs);
if (!iov)
return -ENOMEM;
ksmbd_msg.msg_control = NULL;
ksmbd_msg.msg_controllen = 0;
for (total_read = 0; to_read; total_read += length, to_read -= length) {
try_to_freeze();
if (!ksmbd_conn_alive(conn)) {
total_read = -ESHUTDOWN;
break;
}
segs = kvec_array_init(iov, iov_orig, nr_segs, total_read);
length = kernel_recvmsg(t->sock, &ksmbd_msg,
iov, segs, to_read, 0);
if (length == -EINTR) {
total_read = -ESHUTDOWN;
break;
} else if (ksmbd_conn_need_reconnect(conn)) {
total_read = -EAGAIN;
break;
} else if (length == -ERESTARTSYS || length == -EAGAIN) {
/*
* If max_retries is negative, Allow unlimited
* retries to keep connection with inactive sessions.
*/
if (max_retries == 0) {
total_read = length;
break;
} else if (max_retries > 0) {
max_retries--;
}
usleep_range(1000, 2000);
length = 0;
continue;
} else if (length <= 0) {
total_read = length;
break;
}
}
return total_read;
}
/**
* ksmbd_tcp_read() - read data from socket in given buffer
* @t: TCP transport instance
* @buf: buffer to store read data from socket
* @to_read: number of bytes to read from socket
* @max_retries: number of retries if reading from socket fails
*
* Return: on success return number of bytes read from socket,
* otherwise return error number
*/
static int ksmbd_tcp_read(struct ksmbd_transport *t, char *buf,
unsigned int to_read, int max_retries)
{
struct kvec iov;
iov.iov_base = buf;
iov.iov_len = to_read;
return ksmbd_tcp_readv(TCP_TRANS(t), &iov, 1, to_read, max_retries);
}
static int ksmbd_tcp_writev(struct ksmbd_transport *t, struct kvec *iov,
int nvecs, int size, bool need_invalidate,
unsigned int remote_key)
{
struct msghdr smb_msg = {.msg_flags = MSG_NOSIGNAL};
return kernel_sendmsg(TCP_TRANS(t)->sock, &smb_msg, iov, nvecs, size);
}
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)
{
int ret;
if (!ksmbd_socket)
return;
/* set zero to timeout */
ksmbd_tcp_rcv_timeout(ksmbd_socket, 0);
ksmbd_tcp_snd_timeout(ksmbd_socket, 0);
ret = kernel_sock_shutdown(ksmbd_socket, SHUT_RDWR);
if (ret)
pr_err("Failed to shutdown socket: %d\n", ret);
sock_release(ksmbd_socket);
}
/**
* create_socket - create socket for ksmbd/0
* @iface: interface to bind the created socket to
*
* Return: 0 on success, error number otherwise
*/
static int create_socket(struct interface *iface)
{
int ret;
struct sockaddr_in6 sin6;
struct sockaddr_in sin;
struct socket *ksmbd_socket;
bool ipv4 = false;
ret = sock_create(PF_INET6, SOCK_STREAM, IPPROTO_TCP, &ksmbd_socket);
if (ret) {
if (ret != -EAFNOSUPPORT)
pr_err("Can't create socket for ipv6, fallback to ipv4: %d\n", ret);
ret = sock_create(PF_INET, SOCK_STREAM, IPPROTO_TCP,
&ksmbd_socket);
if (ret) {
pr_err("Can't create socket for ipv4: %d\n", ret);
goto out_clear;
}
sin.sin_family = PF_INET;
sin.sin_addr.s_addr = htonl(INADDR_ANY);
sin.sin_port = htons(server_conf.tcp_port);
ipv4 = true;
} else {
sin6.sin6_family = PF_INET6;
sin6.sin6_addr = in6addr_any;
sin6.sin6_port = htons(server_conf.tcp_port);
lock_sock(ksmbd_socket->sk);
ksmbd_socket->sk->sk_ipv6only = false;
release_sock(ksmbd_socket->sk);
}
ksmbd_tcp_nodelay(ksmbd_socket);
ksmbd_tcp_reuseaddr(ksmbd_socket);
ret = sock_setsockopt(ksmbd_socket,
SOL_SOCKET,
SO_BINDTODEVICE,
KERNEL_SOCKPTR(iface->name),
strlen(iface->name));
if (ret != -ENODEV && ret < 0) {
pr_err("Failed to set SO_BINDTODEVICE: %d\n", ret);
goto out_error;
}
if (ipv4)
ret = kernel_bind(ksmbd_socket, (struct sockaddr *)&sin,
sizeof(sin));
else
ret = kernel_bind(ksmbd_socket, (struct sockaddr *)&sin6,
sizeof(sin6));
if (ret) {
pr_err("Failed to bind socket: %d\n", ret);
goto out_error;
}
ksmbd_socket->sk->sk_rcvtimeo = KSMBD_TCP_RECV_TIMEOUT;
ksmbd_socket->sk->sk_sndtimeo = KSMBD_TCP_SEND_TIMEOUT;
ret = kernel_listen(ksmbd_socket, KSMBD_SOCKET_BACKLOG);
if (ret) {
pr_err("Port listen() error: %d\n", ret);
goto out_error;
}
iface->ksmbd_socket = ksmbd_socket;
ret = ksmbd_tcp_run_kthread(iface);
if (ret) {
pr_err("Can't start ksmbd main kthread: %d\n", ret);
goto out_error;
}
iface->state = IFACE_STATE_CONFIGURED;
return 0;
out_error:
tcp_destroy_socket(ksmbd_socket);
out_clear:
iface->ksmbd_socket = NULL;
return ret;
}
static int ksmbd_netdev_event(struct notifier_block *nb, unsigned long event,
void *ptr)
{
struct net_device *netdev = netdev_notifier_info_to_dev(ptr);
struct interface *iface;
int ret, found = 0;
switch (event) {
case NETDEV_UP:
if (netif_is_bridge_port(netdev))
return NOTIFY_OK;
list_for_each_entry(iface, &iface_list, entry) {
if (!strcmp(iface->name, netdev->name)) {
found = 1;
if (iface->state != IFACE_STATE_DOWN)
break;
ret = create_socket(iface);
if (ret)
return NOTIFY_OK;
break;
}
}
if (!found && bind_additional_ifaces) {
iface = alloc_iface(kstrdup(netdev->name, GFP_KERNEL));
if (!iface)
return NOTIFY_OK;
ret = create_socket(iface);
if (ret)
break;
}
break;
case NETDEV_DOWN:
list_for_each_entry(iface, &iface_list, entry) {
if (!strcmp(iface->name, netdev->name) &&
iface->state == IFACE_STATE_CONFIGURED) {
tcp_stop_kthread(iface->ksmbd_kthread);
iface->ksmbd_kthread = NULL;
mutex_lock(&iface->sock_release_lock);
tcp_destroy_socket(iface->ksmbd_socket);
iface->ksmbd_socket = NULL;
mutex_unlock(&iface->sock_release_lock);
iface->state = IFACE_STATE_DOWN;
break;
}
}
break;
}
return NOTIFY_DONE;
}
static struct notifier_block ksmbd_netdev_notifier = {
.notifier_call = ksmbd_netdev_event,
};
int ksmbd_tcp_init(void)
{
register_netdevice_notifier(&ksmbd_netdev_notifier);
return 0;
}
static void tcp_stop_kthread(struct task_struct *kthread)
{
int ret;
if (!kthread)
return;
ret = kthread_stop(kthread);
if (ret)
pr_err("failed to stop forker thread\n");
}
void ksmbd_tcp_destroy(void)
{
struct interface *iface, *tmp;
unregister_netdevice_notifier(&ksmbd_netdev_notifier);
list_for_each_entry_safe(iface, tmp, &iface_list, entry) {
list_del(&iface->entry);
kfree(iface->name);
kfree(iface);
}
}
static struct interface *alloc_iface(char *ifname)
{
struct interface *iface;
if (!ifname)
return NULL;
iface = kzalloc(sizeof(struct interface), GFP_KERNEL);
if (!iface) {
kfree(ifname);
return NULL;
}
iface->name = ifname;
iface->state = IFACE_STATE_DOWN;
list_add(&iface->entry, &iface_list);
mutex_init(&iface->sock_release_lock);
return iface;
}
int ksmbd_tcp_set_interfaces(char *ifc_list, int ifc_list_sz)
{
int sz = 0;
if (!ifc_list_sz) {
struct net_device *netdev;
rtnl_lock();
for_each_netdev(&init_net, netdev) {
if (netif_is_bridge_port(netdev))
continue;
if (!alloc_iface(kstrdup(netdev->name, GFP_KERNEL))) {
rtnl_unlock();
return -ENOMEM;
}
}
rtnl_unlock();
bind_additional_ifaces = 1;
return 0;
}
while (ifc_list_sz > 0) {
if (!alloc_iface(kstrdup(ifc_list, GFP_KERNEL)))
return -ENOMEM;
sz = strlen(ifc_list);
if (!sz)
break;
ifc_list += sz + 1;
ifc_list_sz -= (sz + 1);
}
bind_additional_ifaces = 0;
return 0;
}
static const struct ksmbd_transport_ops ksmbd_tcp_transport_ops = {
.read = ksmbd_tcp_read,
.writev = ksmbd_tcp_writev,
.disconnect = ksmbd_tcp_disconnect,
};
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