fs/smb/server/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  * @max_retries:        maximum retry count
 299  *
 300  * Return:      on success return number of bytes read from socket,
 301  *              otherwise return error number
 302  */
 303 static int ksmbd_tcp_readv(struct tcp_transport *t, struct kvec *iov_orig,
 304                            unsigned int nr_segs, unsigned int to_read,
 305                            int max_retries)
 306 {
 307         int length = 0;
 308         int total_read;
 309         unsigned int segs;
 310         struct msghdr ksmbd_msg;
 311         struct kvec *iov;
 312         struct ksmbd_conn *conn = KSMBD_TRANS(t)->conn;
 313
 314         iov = get_conn_iovec(t, nr_segs);
 315         if (!iov)
 316                 return -ENOMEM;
 317
 318         ksmbd_msg.msg_control = NULL;
 319         ksmbd_msg.msg_controllen = 0;
 320
 321         for (total_read = 0; to_read; total_read += length, to_read -= length) {
 322                 try_to_freeze();
 323
 324                 if (!ksmbd_conn_alive(conn)) {
 325                         total_read = -ESHUTDOWN;
 326                         break;
 327                 }
 328                 segs = kvec_array_init(iov, iov_orig, nr_segs, total_read);
 329
 330                 length = kernel_recvmsg(t->sock, &ksmbd_msg,
 331                                         iov, segs, to_read, 0);
 332
 333                 if (length == -EINTR) {
 334                         total_read = -ESHUTDOWN;
 335                         break;
 336                 } else if (ksmbd_conn_need_reconnect(conn)) {
 337                         total_read = -EAGAIN;
 338                         break;
 339                 } else if (length == -ERESTARTSYS || length == -EAGAIN) {
 340                         /*
 341                          * If max_retries is negative, Allow unlimited
 342                          * retries to keep connection with inactive sessions.
 343                          */
 344                         if (max_retries == 0) {
 345                                 total_read = length;
 346                                 break;
 347                         } else if (max_retries > 0) {
 348                                 max_retries--;
 349                         }
 350
 351                         usleep_range(1000, 2000);
 352                         length = 0;
 353                         continue;
 354                 } else if (length <= 0) {
 355                         total_read = length;
 356                         break;
 357                 }
 358         }
 359         return total_read;
 360 }
 361
 362 /**
 363  * ksmbd_tcp_read() - read data from socket in given buffer
 364  * @t:          TCP transport instance
 365  * @buf:        buffer to store read data from socket
 366  * @to_read:    number of bytes to read from socket
 367  *
 368  * Return:      on success return number of bytes read from socket,
 369  *              otherwise return error number
 370  */
 371 static int ksmbd_tcp_read(struct ksmbd_transport *t, char *buf,
 372                           unsigned int to_read, int max_retries)
 373 {
 374         struct kvec iov;
 375
 376         iov.iov_base = buf;
 377         iov.iov_len = to_read;
 378
 379         return ksmbd_tcp_readv(TCP_TRANS(t), &iov, 1, to_read, max_retries);
 380 }
 381
 382 static int ksmbd_tcp_writev(struct ksmbd_transport *t, struct kvec *iov,
 383                             int nvecs, int size, bool need_invalidate,
 384                             unsigned int remote_key)
 385
 386 {
 387         struct msghdr smb_msg = {.msg_flags = MSG_NOSIGNAL};
 388
 389         return kernel_sendmsg(TCP_TRANS(t)->sock, &smb_msg, iov, nvecs, size);
 390 }
 391
 392 static void ksmbd_tcp_disconnect(struct ksmbd_transport *t)
 393 {
 394         free_transport(TCP_TRANS(t));
 395         if (server_conf.max_connections)
 396                 atomic_dec(&active_num_conn);
 397 }
 398
 399 static void tcp_destroy_socket(struct socket *ksmbd_socket)
 400 {
 401         int ret;
 402
 403         if (!ksmbd_socket)
 404                 return;
 405
 406         /* set zero to timeout */
 407         ksmbd_tcp_rcv_timeout(ksmbd_socket, 0);
 408         ksmbd_tcp_snd_timeout(ksmbd_socket, 0);
 409
 410         ret = kernel_sock_shutdown(ksmbd_socket, SHUT_RDWR);
 411         if (ret)
 412                 pr_err("Failed to shutdown socket: %d\n", ret);
 413         sock_release(ksmbd_socket);
 414 }
 415
 416 /**
 417  * create_socket - create socket for ksmbd/0
 418  *
 419  * Return:      0 on success, error number otherwise
 420  */
 421 static int create_socket(struct interface *iface)
 422 {
 423         int ret;
 424         struct sockaddr_in6 sin6;
 425         struct sockaddr_in sin;
 426         struct socket *ksmbd_socket;
 427         bool ipv4 = false;
 428
 429         ret = sock_create(PF_INET6, SOCK_STREAM, IPPROTO_TCP, &ksmbd_socket);
 430         if (ret) {
 431                 if (ret != -EAFNOSUPPORT)
 432                         pr_err("Can't create socket for ipv6, fallback to ipv4: %d\n", ret);
 433                 ret = sock_create(PF_INET, SOCK_STREAM, IPPROTO_TCP,
 434                                   &ksmbd_socket);
 435                 if (ret) {
 436                         pr_err("Can't create socket for ipv4: %d\n", ret);
 437                         goto out_clear;
 438                 }
 439
 440                 sin.sin_family = PF_INET;
 441                 sin.sin_addr.s_addr = htonl(INADDR_ANY);
 442                 sin.sin_port = htons(server_conf.tcp_port);
 443                 ipv4 = true;
 444         } else {
 445                 sin6.sin6_family = PF_INET6;
 446                 sin6.sin6_addr = in6addr_any;
 447                 sin6.sin6_port = htons(server_conf.tcp_port);
 448         }
 449
 450         ksmbd_tcp_nodelay(ksmbd_socket);
 451         ksmbd_tcp_reuseaddr(ksmbd_socket);
 452
 453         ret = sock_setsockopt(ksmbd_socket,
 454                               SOL_SOCKET,
 455                               SO_BINDTODEVICE,
 456                               KERNEL_SOCKPTR(iface->name),
 457                               strlen(iface->name));
 458         if (ret != -ENODEV && ret < 0) {
 459                 pr_err("Failed to set SO_BINDTODEVICE: %d\n", ret);
 460                 goto out_error;
 461         }
 462
 463         if (ipv4)
 464                 ret = kernel_bind(ksmbd_socket, (struct sockaddr *)&sin,
 465                                   sizeof(sin));
 466         else
 467                 ret = kernel_bind(ksmbd_socket, (struct sockaddr *)&sin6,
 468                                   sizeof(sin6));
 469         if (ret) {
 470                 pr_err("Failed to bind socket: %d\n", ret);
 471                 goto out_error;
 472         }
 473
 474         ksmbd_socket->sk->sk_rcvtimeo = KSMBD_TCP_RECV_TIMEOUT;
 475         ksmbd_socket->sk->sk_sndtimeo = KSMBD_TCP_SEND_TIMEOUT;
 476
 477         ret = kernel_listen(ksmbd_socket, KSMBD_SOCKET_BACKLOG);
 478         if (ret) {
 479                 pr_err("Port listen() error: %d\n", ret);
 480                 goto out_error;
 481         }
 482
 483         iface->ksmbd_socket = ksmbd_socket;
 484         ret = ksmbd_tcp_run_kthread(iface);
 485         if (ret) {
 486                 pr_err("Can't start ksmbd main kthread: %d\n", ret);
 487                 goto out_error;
 488         }
 489         iface->state = IFACE_STATE_CONFIGURED;
 490
 491         return 0;
 492
 493 out_error:
 494         tcp_destroy_socket(ksmbd_socket);
 495 out_clear:
 496         iface->ksmbd_socket = NULL;
 497         return ret;
 498 }
 499
 500 static int ksmbd_netdev_event(struct notifier_block *nb, unsigned long event,
 501                               void *ptr)
 502 {
 503         struct net_device *netdev = netdev_notifier_info_to_dev(ptr);
 504         struct interface *iface;
 505         int ret, found = 0;
 506
 507         switch (event) {
 508         case NETDEV_UP:
 509                 if (netif_is_bridge_port(netdev))
 510                         return NOTIFY_OK;
 511
 512                 list_for_each_entry(iface, &iface_list, entry) {
 513                         if (!strcmp(iface->name, netdev->name)) {
 514                                 found = 1;
 515                                 if (iface->state != IFACE_STATE_DOWN)
 516                                         break;
 517                                 ret = create_socket(iface);
 518                                 if (ret)
 519                                         return NOTIFY_OK;
 520                                 break;
 521                         }
 522                 }
 523                 if (!found && bind_additional_ifaces) {
 524                         iface = alloc_iface(kstrdup(netdev->name, GFP_KERNEL));
 525                         if (!iface)
 526                                 return NOTIFY_OK;
 527                         ret = create_socket(iface);
 528                         if (ret)
 529                                 break;
 530                 }
 531                 break;
 532         case NETDEV_DOWN:
 533                 list_for_each_entry(iface, &iface_list, entry) {
 534                         if (!strcmp(iface->name, netdev->name) &&
 535                             iface->state == IFACE_STATE_CONFIGURED) {
 536                                 tcp_stop_kthread(iface->ksmbd_kthread);
 537                                 iface->ksmbd_kthread = NULL;
 538                                 mutex_lock(&iface->sock_release_lock);
 539                                 tcp_destroy_socket(iface->ksmbd_socket);
 540                                 iface->ksmbd_socket = NULL;
 541                                 mutex_unlock(&iface->sock_release_lock);
 542
 543                                 iface->state = IFACE_STATE_DOWN;
 544                                 break;
 545                         }
 546                 }
 547                 break;
 548         }
 549
 550         return NOTIFY_DONE;
 551 }
 552
 553 static struct notifier_block ksmbd_netdev_notifier = {
 554         .notifier_call = ksmbd_netdev_event,
 555 };
 556
 557 int ksmbd_tcp_init(void)
 558 {
 559         register_netdevice_notifier(&ksmbd_netdev_notifier);
 560
 561         return 0;
 562 }
 563
 564 static void tcp_stop_kthread(struct task_struct *kthread)
 565 {
 566         int ret;
 567
 568         if (!kthread)
 569                 return;
 570
 571         ret = kthread_stop(kthread);
 572         if (ret)
 573                 pr_err("failed to stop forker thread\n");
 574 }
 575
 576 void ksmbd_tcp_destroy(void)
 577 {
 578         struct interface *iface, *tmp;
 579
 580         unregister_netdevice_notifier(&ksmbd_netdev_notifier);
 581
 582         list_for_each_entry_safe(iface, tmp, &iface_list, entry) {
 583                 list_del(&iface->entry);
 584                 kfree(iface->name);
 585                 kfree(iface);
 586         }
 587 }
 588
 589 static struct interface *alloc_iface(char *ifname)
 590 {
 591         struct interface *iface;
 592
 593         if (!ifname)
 594                 return NULL;
 595
 596         iface = kzalloc(sizeof(struct interface), GFP_KERNEL);
 597         if (!iface) {
 598                 kfree(ifname);
 599                 return NULL;
 600         }
 601
 602         iface->name = ifname;
 603         iface->state = IFACE_STATE_DOWN;
 604         list_add(&iface->entry, &iface_list);
 605         mutex_init(&iface->sock_release_lock);
 606         return iface;
 607 }
 608
 609 int ksmbd_tcp_set_interfaces(char *ifc_list, int ifc_list_sz)
 610 {
 611         int sz = 0;
 612
 613         if (!ifc_list_sz) {
 614                 struct net_device *netdev;
 615
 616                 rtnl_lock();
 617                 for_each_netdev(&init_net, netdev) {
 618                         if (netif_is_bridge_port(netdev))
 619                                 continue;
 620                         if (!alloc_iface(kstrdup(netdev->name, GFP_KERNEL)))
 621                                 return -ENOMEM;
 622                 }
 623                 rtnl_unlock();
 624                 bind_additional_ifaces = 1;
 625                 return 0;
 626         }
 627
 628         while (ifc_list_sz > 0) {
 629                 if (!alloc_iface(kstrdup(ifc_list, GFP_KERNEL)))
 630                         return -ENOMEM;
 631
 632                 sz = strlen(ifc_list);
 633                 if (!sz)
 634                         break;
 635
 636                 ifc_list += sz + 1;
 637                 ifc_list_sz -= (sz + 1);
 638         }
 639
 640         bind_additional_ifaces = 0;
 641
 642         return 0;
 643 }
 644
 645 static struct ksmbd_transport_ops ksmbd_tcp_transport_ops = {
 646         .read           = ksmbd_tcp_read,
 647         .writev         = ksmbd_tcp_writev,
 648         .disconnect     = ksmbd_tcp_disconnect,
 649 };