fs/ksmbd/transport_tcp.c

   1 // SPDX-License-Identifier: GPL-2.0-or-later
   2 /*
   3  *   Copyright (C) 2016 Namjae Jeon <linkinjeon@kernel.org>
   4  *   Copyright (C) 2018 Samsung Electronics Co., Ltd.
   5  */
   6
   7 #include <linux/freezer.h>
   8
   9 #include "smb_common.h"
  10 #include "server.h"
  11 #include "auth.h"
  12 #include "connection.h"
  13 #include "transport_tcp.h"
  14
  15 #define IFACE_STATE_DOWN                BIT(0)
  16 #define IFACE_STATE_CONFIGURED          BIT(1)
  17
  18 static atomic_t active_num_conn;
  19
  20 struct interface {
  21         struct task_struct      *ksmbd_kthread;
  22         struct socket           *ksmbd_socket;
  23         struct list_head        entry;
  24         char                    *name;
  25         struct mutex            sock_release_lock;
  26         int                     state;
  27 };
  28
  29 static LIST_HEAD(iface_list);
  30
  31 static int bind_additional_ifaces;
  32
  33 struct tcp_transport {
  34         struct ksmbd_transport          transport;
  35         struct socket                   *sock;
  36         struct kvec                     *iov;
  37         unsigned int                    nr_iov;
  38 };
  39
  40 static struct ksmbd_transport_ops ksmbd_tcp_transport_ops;
  41
  42 static void tcp_stop_kthread(struct task_struct *kthread);
  43 static struct interface *alloc_iface(char *ifname);
  44
  45 #define KSMBD_TRANS(t)  (&(t)->transport)
  46 #define TCP_TRANS(t)    ((struct tcp_transport *)container_of(t, \
  47                                 struct tcp_transport, transport))
  48
  49 static inline void ksmbd_tcp_nodelay(struct socket *sock)
  50 {
  51         tcp_sock_set_nodelay(sock->sk);
  52 }
  53
  54 static inline void ksmbd_tcp_reuseaddr(struct socket *sock)
  55 {
  56         sock_set_reuseaddr(sock->sk);
  57 }
  58
  59 static inline void ksmbd_tcp_rcv_timeout(struct socket *sock, s64 secs)
  60 {
  61         lock_sock(sock->sk);
  62         if (secs && secs < MAX_SCHEDULE_TIMEOUT / HZ - 1)
  63                 sock->sk->sk_rcvtimeo = secs * HZ;
  64         else
  65                 sock->sk->sk_rcvtimeo = MAX_SCHEDULE_TIMEOUT;
  66         release_sock(sock->sk);
  67 }
  68
  69 static inline void ksmbd_tcp_snd_timeout(struct socket *sock, s64 secs)
  70 {
  71         sock_set_sndtimeo(sock->sk, secs);
  72 }
  73
  74 static struct tcp_transport *alloc_transport(struct socket *client_sk)
  75 {
  76         struct tcp_transport *t;
  77         struct ksmbd_conn *conn;
  78
  79         t = kzalloc(sizeof(*t), GFP_KERNEL);
  80         if (!t)
  81                 return NULL;
  82         t->sock = client_sk;
  83
  84         conn = ksmbd_conn_alloc();
  85         if (!conn) {
  86                 kfree(t);
  87                 return NULL;
  88         }
  89
  90         conn->transport = KSMBD_TRANS(t);
  91         KSMBD_TRANS(t)->conn = conn;
  92         KSMBD_TRANS(t)->ops = &ksmbd_tcp_transport_ops;
  93         return t;
  94 }
  95
  96 static void free_transport(struct tcp_transport *t)
  97 {
  98         kernel_sock_shutdown(t->sock, SHUT_RDWR);
  99         sock_release(t->sock);
 100         t->sock = NULL;
 101
 102         ksmbd_conn_free(KSMBD_TRANS(t)->conn);
 103         kfree(t->iov);
 104         kfree(t);
 105 }
 106
 107 /**
 108  * kvec_array_init() - initialize a IO vector segment
 109  * @new:        IO vector to be initialized
 110  * @iov:        base IO vector
 111  * @nr_segs:    number of segments in base iov
 112  * @bytes:      total iovec length so far for read
 113  *
 114  * Return:      Number of IO segments
 115  */
 116 static unsigned int kvec_array_init(struct kvec *new, struct kvec *iov,
 117                                     unsigned int nr_segs, size_t bytes)
 118 {
 119         size_t base = 0;
 120
 121         while (bytes || !iov->iov_len) {
 122                 int copy = min(bytes, iov->iov_len);
 123
 124                 bytes -= copy;
 125                 base += copy;
 126                 if (iov->iov_len == base) {
 127                         iov++;
 128                         nr_segs--;
 129                         base = 0;
 130                 }
 131         }
 132
 133         memcpy(new, iov, sizeof(*iov) * nr_segs);
 134         new->iov_base += base;
 135         new->iov_len -= base;
 136         return nr_segs;
 137 }
 138
 139 /**
 140  * get_conn_iovec() - get connection iovec for reading from socket
 141  * @t:          TCP transport instance
 142  * @nr_segs:    number of segments in iov
 143  *
 144  * Return:      return existing or newly allocate iovec
 145  */
 146 static struct kvec *get_conn_iovec(struct tcp_transport *t, unsigned int nr_segs)
 147 {
 148         struct kvec *new_iov;
 149
 150         if (t->iov && nr_segs <= t->nr_iov)
 151                 return t->iov;
 152
 153         /* not big enough -- allocate a new one and release the old */
 154         new_iov = kmalloc_array(nr_segs, sizeof(*new_iov), GFP_KERNEL);
 155         if (new_iov) {
 156                 kfree(t->iov);
 157                 t->iov = new_iov;
 158                 t->nr_iov = nr_segs;
 159         }
 160         return new_iov;
 161 }
 162
 163 static unsigned short ksmbd_tcp_get_port(const struct sockaddr *sa)
 164 {
 165         switch (sa->sa_family) {
 166         case AF_INET:
 167                 return ntohs(((struct sockaddr_in *)sa)->sin_port);
 168         case AF_INET6:
 169                 return ntohs(((struct sockaddr_in6 *)sa)->sin6_port);
 170         }
 171         return 0;
 172 }
 173
 174 /**
 175  * ksmbd_tcp_new_connection() - create a new tcp session on mount
 176  * @client_sk:  socket associated with new connection
 177  *
 178  * whenever a new connection is requested, create a conn thread
 179  * (session thread) to handle new incoming smb requests from the connection
 180  *
 181  * Return:      0 on success, otherwise error
 182  */
 183 static int ksmbd_tcp_new_connection(struct socket *client_sk)
 184 {
 185         struct sockaddr *csin;
 186         int rc = 0;
 187         struct tcp_transport *t;
 188
 189         t = alloc_transport(client_sk);
 190         if (!t) {
 191                 sock_release(client_sk);
 192                 return -ENOMEM;
 193         }
 194
 195         csin = KSMBD_TCP_PEER_SOCKADDR(KSMBD_TRANS(t)->conn);
 196         if (kernel_getpeername(client_sk, csin) < 0) {
 197                 pr_err("client ip resolution failed\n");
 198                 rc = -EINVAL;
 199                 goto out_error;
 200         }
 201
 202         KSMBD_TRANS(t)->handler = kthread_run(ksmbd_conn_handler_loop,
 203                                               KSMBD_TRANS(t)->conn,
 204                                               "ksmbd:%u",
 205                                               ksmbd_tcp_get_port(csin));
 206         if (IS_ERR(KSMBD_TRANS(t)->handler)) {
 207                 pr_err("cannot start conn thread\n");
 208                 rc = PTR_ERR(KSMBD_TRANS(t)->handler);
 209                 free_transport(t);
 210         }
 211         return rc;
 212
 213 out_error:
 214         free_transport(t);
 215         return rc;
 216 }
 217
 218 /**
 219  * ksmbd_kthread_fn() - listen to new SMB connections and callback server
 220  * @p:          arguments to forker thread
 221  *
 222  * Return:      0 on success, error number otherwise
 223  */
 224 static int ksmbd_kthread_fn(void *p)
 225 {
 226         struct socket *client_sk = NULL;
 227         struct interface *iface = (struct interface *)p;
 228         int ret;
 229
 230         while (!kthread_should_stop()) {
 231                 mutex_lock(&iface->sock_release_lock);
 232                 if (!iface->ksmbd_socket) {
 233                         mutex_unlock(&iface->sock_release_lock);
 234                         break;
 235                 }
 236                 ret = kernel_accept(iface->ksmbd_socket, &client_sk,
 237                                     SOCK_NONBLOCK);
 238                 mutex_unlock(&iface->sock_release_lock);
 239                 if (ret) {
 240                         if (ret == -EAGAIN)
 241                                 /* check for new connections every 100 msecs */
 242                                 schedule_timeout_interruptible(HZ / 10);
 243                         continue;
 244                 }
 245
 246                 if (server_conf.max_connections &&
 247                     atomic_inc_return(&active_num_conn) >= server_conf.max_connections) {
 248                         pr_info_ratelimited("Limit the maximum number of connections(%u)\n",
 249                                             atomic_read(&active_num_conn));
 250                         atomic_dec(&active_num_conn);
 251                         sock_release(client_sk);
 252                         continue;
 253                 }
 254
 255                 ksmbd_debug(CONN, "connect success: accepted new connection\n");
 256                 client_sk->sk->sk_rcvtimeo = KSMBD_TCP_RECV_TIMEOUT;
 257                 client_sk->sk->sk_sndtimeo = KSMBD_TCP_SEND_TIMEOUT;
 258
 259                 ksmbd_tcp_new_connection(client_sk);
 260         }
 261
 262         ksmbd_debug(CONN, "releasing socket\n");
 263         return 0;
 264 }
 265
 266 /**
 267  * ksmbd_tcp_run_kthread() - start forker thread
 268  * @iface: pointer to struct interface
 269  *
 270  * start forker thread(ksmbd/0) at module init time to listen
 271  * on port 445 for new SMB connection requests. It creates per connection
 272  * server threads(ksmbd/x)
 273  *
 274  * Return:      0 on success or error number
 275  */
 276 static int ksmbd_tcp_run_kthread(struct interface *iface)
 277 {
 278         int rc;
 279         struct task_struct *kthread;
 280
 281         kthread = kthread_run(ksmbd_kthread_fn, (void *)iface, "ksmbd-%s",
 282                               iface->name);
 283         if (IS_ERR(kthread)) {
 284                 rc = PTR_ERR(kthread);
 285                 return rc;
 286         }
 287         iface->ksmbd_kthread = kthread;
 288
 289         return 0;
 290 }
 291
 292 /**
 293  * ksmbd_tcp_readv() - read data from socket in given iovec
 294  * @t:          TCP transport instance
 295  * @iov_orig:   base IO vector
 296  * @nr_segs:    number of segments in base iov
 297  * @to_read:    number of bytes to read from socket
 298  *
 299  * Return:      on success return number of bytes read from socket,
 300  *              otherwise return error number
 301  */
 302 static int ksmbd_tcp_readv(struct tcp_transport *t, struct kvec *iov_orig,
 303                            unsigned int nr_segs, unsigned int to_read)
 304 {
 305         int length = 0;
 306         int total_read;
 307         unsigned int segs;
 308         struct msghdr ksmbd_msg;
 309         struct kvec *iov;
 310         struct ksmbd_conn *conn = KSMBD_TRANS(t)->conn;
 311         int max_retry = 2;
 312
 313         iov = get_conn_iovec(t, nr_segs);
 314         if (!iov)
 315                 return -ENOMEM;
 316
 317         ksmbd_msg.msg_control = NULL;
 318         ksmbd_msg.msg_controllen = 0;
 319
 320         for (total_read = 0; to_read; total_read += length, to_read -= length) {
 321                 try_to_freeze();
 322
 323                 if (!ksmbd_conn_alive(conn)) {
 324                         total_read = -ESHUTDOWN;
 325                         break;
 326                 }
 327                 segs = kvec_array_init(iov, iov_orig, nr_segs, total_read);
 328
 329                 length = kernel_recvmsg(t->sock, &ksmbd_msg,
 330                                         iov, segs, to_read, 0);
 331
 332                 if (length == -EINTR) {
 333                         total_read = -ESHUTDOWN;
 334                         break;
 335                 } else if (conn->status == KSMBD_SESS_NEED_RECONNECT) {
 336                         total_read = -EAGAIN;
 337                         break;
 338                 } else if ((length == -ERESTARTSYS || length == -EAGAIN) &&
 339                            max_retry) {
 340                         usleep_range(1000, 2000);
 341                         length = 0;
 342                         max_retry--;
 343                         continue;
 344                 } else if (length <= 0) {
 345                         total_read = -EAGAIN;
 346                         break;
 347                 }
 348         }
 349         return total_read;
 350 }
 351
 352 /**
 353  * ksmbd_tcp_read() - read data from socket in given buffer
 354  * @t:          TCP transport instance
 355  * @buf:        buffer to store read data from socket
 356  * @to_read:    number of bytes to read from socket
 357  *
 358  * Return:      on success return number of bytes read from socket,
 359  *              otherwise return error number
 360  */
 361 static int ksmbd_tcp_read(struct ksmbd_transport *t, char *buf, unsigned int to_read)
 362 {
 363         struct kvec iov;
 364
 365         iov.iov_base = buf;
 366         iov.iov_len = to_read;
 367
 368         return ksmbd_tcp_readv(TCP_TRANS(t), &iov, 1, to_read);
 369 }
 370
 371 static int ksmbd_tcp_writev(struct ksmbd_transport *t, struct kvec *iov,
 372                             int nvecs, int size, bool need_invalidate,
 373                             unsigned int remote_key)
 374
 375 {
 376         struct msghdr smb_msg = {.msg_flags = MSG_NOSIGNAL};
 377
 378         return kernel_sendmsg(TCP_TRANS(t)->sock, &smb_msg, iov, nvecs, size);
 379 }
 380
 381 static void ksmbd_tcp_disconnect(struct ksmbd_transport *t)
 382 {
 383         free_transport(TCP_TRANS(t));
 384         if (server_conf.max_connections)
 385                 atomic_dec(&active_num_conn);
 386 }
 387
 388 static void tcp_destroy_socket(struct socket *ksmbd_socket)
 389 {
 390         int ret;
 391
 392         if (!ksmbd_socket)
 393                 return;
 394
 395         /* set zero to timeout */
 396         ksmbd_tcp_rcv_timeout(ksmbd_socket, 0);
 397         ksmbd_tcp_snd_timeout(ksmbd_socket, 0);
 398
 399         ret = kernel_sock_shutdown(ksmbd_socket, SHUT_RDWR);
 400         if (ret)
 401                 pr_err("Failed to shutdown socket: %d\n", ret);
 402         sock_release(ksmbd_socket);
 403 }
 404
 405 /**
 406  * create_socket - create socket for ksmbd/0
 407  *
 408  * Return:      0 on success, error number otherwise
 409  */
 410 static int create_socket(struct interface *iface)
 411 {
 412         int ret;
 413         struct sockaddr_in6 sin6;
 414         struct sockaddr_in sin;
 415         struct socket *ksmbd_socket;
 416         bool ipv4 = false;
 417
 418         ret = sock_create(PF_INET6, SOCK_STREAM, IPPROTO_TCP, &ksmbd_socket);
 419         if (ret) {
 420                 if (ret != -EAFNOSUPPORT)
 421                         pr_err("Can't create socket for ipv6, fallback to ipv4: %d\n", ret);
 422                 ret = sock_create(PF_INET, SOCK_STREAM, IPPROTO_TCP,
 423                                   &ksmbd_socket);
 424                 if (ret) {
 425                         pr_err("Can't create socket for ipv4: %d\n", ret);
 426                         goto out_clear;
 427                 }
 428
 429                 sin.sin_family = PF_INET;
 430                 sin.sin_addr.s_addr = htonl(INADDR_ANY);
 431                 sin.sin_port = htons(server_conf.tcp_port);
 432                 ipv4 = true;
 433         } else {
 434                 sin6.sin6_family = PF_INET6;
 435                 sin6.sin6_addr = in6addr_any;
 436                 sin6.sin6_port = htons(server_conf.tcp_port);
 437         }
 438
 439         ksmbd_tcp_nodelay(ksmbd_socket);
 440         ksmbd_tcp_reuseaddr(ksmbd_socket);
 441
 442         ret = sock_setsockopt(ksmbd_socket,
 443                               SOL_SOCKET,
 444                               SO_BINDTODEVICE,
 445                               KERNEL_SOCKPTR(iface->name),
 446                               strlen(iface->name));
 447         if (ret != -ENODEV && ret < 0) {
 448                 pr_err("Failed to set SO_BINDTODEVICE: %d\n", ret);
 449                 goto out_error;
 450         }
 451
 452         if (ipv4)
 453                 ret = kernel_bind(ksmbd_socket, (struct sockaddr *)&sin,
 454                                   sizeof(sin));
 455         else
 456                 ret = kernel_bind(ksmbd_socket, (struct sockaddr *)&sin6,
 457                                   sizeof(sin6));
 458         if (ret) {
 459                 pr_err("Failed to bind socket: %d\n", ret);
 460                 goto out_error;
 461         }
 462
 463         ksmbd_socket->sk->sk_rcvtimeo = KSMBD_TCP_RECV_TIMEOUT;
 464         ksmbd_socket->sk->sk_sndtimeo = KSMBD_TCP_SEND_TIMEOUT;
 465
 466         ret = kernel_listen(ksmbd_socket, KSMBD_SOCKET_BACKLOG);
 467         if (ret) {
 468                 pr_err("Port listen() error: %d\n", ret);
 469                 goto out_error;
 470         }
 471
 472         iface->ksmbd_socket = ksmbd_socket;
 473         ret = ksmbd_tcp_run_kthread(iface);
 474         if (ret) {
 475                 pr_err("Can't start ksmbd main kthread: %d\n", ret);
 476                 goto out_error;
 477         }
 478         iface->state = IFACE_STATE_CONFIGURED;
 479
 480         return 0;
 481
 482 out_error:
 483         tcp_destroy_socket(ksmbd_socket);
 484 out_clear:
 485         iface->ksmbd_socket = NULL;
 486         return ret;
 487 }
 488
 489 static int ksmbd_netdev_event(struct notifier_block *nb, unsigned long event,
 490                               void *ptr)
 491 {
 492         struct net_device *netdev = netdev_notifier_info_to_dev(ptr);
 493         struct interface *iface;
 494         int ret, found = 0;
 495
 496         switch (event) {
 497         case NETDEV_UP:
 498                 if (netif_is_bridge_port(netdev))
 499                         return NOTIFY_OK;
 500
 501                 list_for_each_entry(iface, &iface_list, entry) {
 502                         if (!strcmp(iface->name, netdev->name)) {
 503                                 found = 1;
 504                                 if (iface->state != IFACE_STATE_DOWN)
 505                                         break;
 506                                 ret = create_socket(iface);
 507                                 if (ret)
 508                                         return NOTIFY_OK;
 509                                 break;
 510                         }
 511                 }
 512                 if (!found && bind_additional_ifaces) {
 513                         iface = alloc_iface(kstrdup(netdev->name, GFP_KERNEL));
 514                         if (!iface)
 515                                 return NOTIFY_OK;
 516                         ret = create_socket(iface);
 517                         if (ret)
 518                                 break;
 519                 }
 520                 break;
 521         case NETDEV_DOWN:
 522                 list_for_each_entry(iface, &iface_list, entry) {
 523                         if (!strcmp(iface->name, netdev->name) &&
 524                             iface->state == IFACE_STATE_CONFIGURED) {
 525                                 tcp_stop_kthread(iface->ksmbd_kthread);
 526                                 iface->ksmbd_kthread = NULL;
 527                                 mutex_lock(&iface->sock_release_lock);
 528                                 tcp_destroy_socket(iface->ksmbd_socket);
 529                                 iface->ksmbd_socket = NULL;
 530                                 mutex_unlock(&iface->sock_release_lock);
 531
 532                                 iface->state = IFACE_STATE_DOWN;
 533                                 break;
 534                         }
 535                 }
 536                 break;
 537         }
 538
 539         return NOTIFY_DONE;
 540 }
 541
 542 static struct notifier_block ksmbd_netdev_notifier = {
 543         .notifier_call = ksmbd_netdev_event,
 544 };
 545
 546 int ksmbd_tcp_init(void)
 547 {
 548         register_netdevice_notifier(&ksmbd_netdev_notifier);
 549
 550         return 0;
 551 }
 552
 553 static void tcp_stop_kthread(struct task_struct *kthread)
 554 {
 555         int ret;
 556
 557         if (!kthread)
 558                 return;
 559
 560         ret = kthread_stop(kthread);
 561         if (ret)
 562                 pr_err("failed to stop forker thread\n");
 563 }
 564
 565 void ksmbd_tcp_destroy(void)
 566 {
 567         struct interface *iface, *tmp;
 568
 569         unregister_netdevice_notifier(&ksmbd_netdev_notifier);
 570
 571         list_for_each_entry_safe(iface, tmp, &iface_list, entry) {
 572                 list_del(&iface->entry);
 573                 kfree(iface->name);
 574                 kfree(iface);
 575         }
 576 }
 577
 578 static struct interface *alloc_iface(char *ifname)
 579 {
 580         struct interface *iface;
 581
 582         if (!ifname)
 583                 return NULL;
 584
 585         iface = kzalloc(sizeof(struct interface), GFP_KERNEL);
 586         if (!iface) {
 587                 kfree(ifname);
 588                 return NULL;
 589         }
 590
 591         iface->name = ifname;
 592         iface->state = IFACE_STATE_DOWN;
 593         list_add(&iface->entry, &iface_list);
 594         mutex_init(&iface->sock_release_lock);
 595         return iface;
 596 }
 597
 598 int ksmbd_tcp_set_interfaces(char *ifc_list, int ifc_list_sz)
 599 {
 600         int sz = 0;
 601
 602         if (!ifc_list_sz) {
 603                 struct net_device *netdev;
 604
 605                 rtnl_lock();
 606                 for_each_netdev(&init_net, netdev) {
 607                         if (netif_is_bridge_port(netdev))
 608                                 continue;
 609                         if (!alloc_iface(kstrdup(netdev->name, GFP_KERNEL)))
 610                                 return -ENOMEM;
 611                 }
 612                 rtnl_unlock();
 613                 bind_additional_ifaces = 1;
 614                 return 0;
 615         }
 616
 617         while (ifc_list_sz > 0) {
 618                 if (!alloc_iface(kstrdup(ifc_list, GFP_KERNEL)))
 619                         return -ENOMEM;
 620
 621                 sz = strlen(ifc_list);
 622                 if (!sz)
 623                         break;
 624
 625                 ifc_list += sz + 1;
 626                 ifc_list_sz -= (sz + 1);
 627         }
 628
 629         bind_additional_ifaces = 0;
 630
 631         return 0;
 632 }
 633
 634 static struct ksmbd_transport_ops ksmbd_tcp_transport_ops = {
 635         .read           = ksmbd_tcp_read,
 636         .writev         = ksmbd_tcp_writev,
 637         .disconnect     = ksmbd_tcp_disconnect,
 638 };