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