fs/ksmbd/smb2misc.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 "glob.h"
   8 #include "nterr.h"
   9 #include "smb2pdu.h"
  10 #include "smb_common.h"
  11 #include "smbstatus.h"
  12 #include "mgmt/user_session.h"
  13 #include "connection.h"
  14
  15 static int check_smb2_hdr(struct smb2_hdr *hdr)
  16 {
  17         /*
  18          * Make sure that this really is an SMB, that it is a response.
  19          */
  20         if (hdr->Flags & SMB2_FLAGS_SERVER_TO_REDIR)
  21                 return 1;
  22         return 0;
  23 }
  24
  25 /*
  26  *  The following table defines the expected "StructureSize" of SMB2 requests
  27  *  in order by SMB2 command.  This is similar to "wct" in SMB/CIFS requests.
  28  *
  29  *  Note that commands are defined in smb2pdu.h in le16 but the array below is
  30  *  indexed by command in host byte order
  31  */
  32 static const __le16 smb2_req_struct_sizes[NUMBER_OF_SMB2_COMMANDS] = {
  33         /* SMB2_NEGOTIATE */ cpu_to_le16(36),
  34         /* SMB2_SESSION_SETUP */ cpu_to_le16(25),
  35         /* SMB2_LOGOFF */ cpu_to_le16(4),
  36         /* SMB2_TREE_CONNECT */ cpu_to_le16(9),
  37         /* SMB2_TREE_DISCONNECT */ cpu_to_le16(4),
  38         /* SMB2_CREATE */ cpu_to_le16(57),
  39         /* SMB2_CLOSE */ cpu_to_le16(24),
  40         /* SMB2_FLUSH */ cpu_to_le16(24),
  41         /* SMB2_READ */ cpu_to_le16(49),
  42         /* SMB2_WRITE */ cpu_to_le16(49),
  43         /* SMB2_LOCK */ cpu_to_le16(48),
  44         /* SMB2_IOCTL */ cpu_to_le16(57),
  45         /* SMB2_CANCEL */ cpu_to_le16(4),
  46         /* SMB2_ECHO */ cpu_to_le16(4),
  47         /* SMB2_QUERY_DIRECTORY */ cpu_to_le16(33),
  48         /* SMB2_CHANGE_NOTIFY */ cpu_to_le16(32),
  49         /* SMB2_QUERY_INFO */ cpu_to_le16(41),
  50         /* SMB2_SET_INFO */ cpu_to_le16(33),
  51         /* use 44 for lease break */
  52         /* SMB2_OPLOCK_BREAK */ cpu_to_le16(36)
  53 };
  54
  55 /*
  56  * The size of the variable area depends on the offset and length fields
  57  * located in different fields for various SMB2 requests. SMB2 requests
  58  * with no variable length info, show an offset of zero for the offset field.
  59  */
  60 static const bool has_smb2_data_area[NUMBER_OF_SMB2_COMMANDS] = {
  61         /* SMB2_NEGOTIATE */ true,
  62         /* SMB2_SESSION_SETUP */ true,
  63         /* SMB2_LOGOFF */ false,
  64         /* SMB2_TREE_CONNECT */ true,
  65         /* SMB2_TREE_DISCONNECT */ false,
  66         /* SMB2_CREATE */ true,
  67         /* SMB2_CLOSE */ false,
  68         /* SMB2_FLUSH */ false,
  69         /* SMB2_READ */ true,
  70         /* SMB2_WRITE */ true,
  71         /* SMB2_LOCK */ true,
  72         /* SMB2_IOCTL */ true,
  73         /* SMB2_CANCEL */ false, /* BB CHECK this not listed in documentation */
  74         /* SMB2_ECHO */ false,
  75         /* SMB2_QUERY_DIRECTORY */ true,
  76         /* SMB2_CHANGE_NOTIFY */ false,
  77         /* SMB2_QUERY_INFO */ true,
  78         /* SMB2_SET_INFO */ true,
  79         /* SMB2_OPLOCK_BREAK */ false
  80 };
  81
  82 /*
  83  * Set length of the data area and the offset to arguments.
  84  * if they are invalid, return error.
  85  */
  86 static int smb2_get_data_area_len(unsigned int *off, unsigned int *len,
  87                                   struct smb2_hdr *hdr)
  88 {
  89         int ret = 0;
  90
  91         *off = 0;
  92         *len = 0;
  93
  94         /* error reqeusts do not have data area */
  95         if (hdr->Status && hdr->Status != STATUS_MORE_PROCESSING_REQUIRED &&
  96             (((struct smb2_err_rsp *)hdr)->StructureSize) == SMB2_ERROR_STRUCTURE_SIZE2_LE)
  97                 return ret;
  98
  99         /*
 100          * Following commands have data areas so we have to get the location
 101          * of the data buffer offset and data buffer length for the particular
 102          * command.
 103          */
 104         switch (hdr->Command) {
 105         case SMB2_SESSION_SETUP:
 106                 *off = le16_to_cpu(((struct smb2_sess_setup_req *)hdr)->SecurityBufferOffset);
 107                 *len = le16_to_cpu(((struct smb2_sess_setup_req *)hdr)->SecurityBufferLength);
 108                 break;
 109         case SMB2_TREE_CONNECT:
 110                 *off = le16_to_cpu(((struct smb2_tree_connect_req *)hdr)->PathOffset);
 111                 *len = le16_to_cpu(((struct smb2_tree_connect_req *)hdr)->PathLength);
 112                 break;
 113         case SMB2_CREATE:
 114         {
 115                 if (((struct smb2_create_req *)hdr)->CreateContextsLength) {
 116                         *off = le32_to_cpu(((struct smb2_create_req *)
 117                                 hdr)->CreateContextsOffset);
 118                         *len = le32_to_cpu(((struct smb2_create_req *)
 119                                 hdr)->CreateContextsLength);
 120                         break;
 121                 }
 122
 123                 *off = le16_to_cpu(((struct smb2_create_req *)hdr)->NameOffset);
 124                 *len = le16_to_cpu(((struct smb2_create_req *)hdr)->NameLength);
 125                 break;
 126         }
 127         case SMB2_QUERY_INFO:
 128                 *off = le16_to_cpu(((struct smb2_query_info_req *)hdr)->InputBufferOffset);
 129                 *len = le32_to_cpu(((struct smb2_query_info_req *)hdr)->InputBufferLength);
 130                 break;
 131         case SMB2_SET_INFO:
 132                 *off = le16_to_cpu(((struct smb2_set_info_req *)hdr)->BufferOffset);
 133                 *len = le32_to_cpu(((struct smb2_set_info_req *)hdr)->BufferLength);
 134                 break;
 135         case SMB2_READ:
 136                 *off = le16_to_cpu(((struct smb2_read_req *)hdr)->ReadChannelInfoOffset);
 137                 *len = le16_to_cpu(((struct smb2_read_req *)hdr)->ReadChannelInfoLength);
 138                 break;
 139         case SMB2_WRITE:
 140                 if (((struct smb2_write_req *)hdr)->DataOffset) {
 141                         *off = le16_to_cpu(((struct smb2_write_req *)hdr)->DataOffset);
 142                         *len = le32_to_cpu(((struct smb2_write_req *)hdr)->Length);
 143                         break;
 144                 }
 145
 146                 *off = le16_to_cpu(((struct smb2_write_req *)hdr)->WriteChannelInfoOffset);
 147                 *len = le16_to_cpu(((struct smb2_write_req *)hdr)->WriteChannelInfoLength);
 148                 break;
 149         case SMB2_QUERY_DIRECTORY:
 150                 *off = le16_to_cpu(((struct smb2_query_directory_req *)hdr)->FileNameOffset);
 151                 *len = le16_to_cpu(((struct smb2_query_directory_req *)hdr)->FileNameLength);
 152                 break;
 153         case SMB2_LOCK:
 154         {
 155                 int lock_count;
 156
 157                 /*
 158                  * smb2_lock request size is 48 included single
 159                  * smb2_lock_element structure size.
 160                  */
 161                 lock_count = le16_to_cpu(((struct smb2_lock_req *)hdr)->LockCount) - 1;
 162                 if (lock_count > 0) {
 163                         *off = __SMB2_HEADER_STRUCTURE_SIZE + 48;
 164                         *len = sizeof(struct smb2_lock_element) * lock_count;
 165                 }
 166                 break;
 167         }
 168         case SMB2_IOCTL:
 169                 *off = le32_to_cpu(((struct smb2_ioctl_req *)hdr)->InputOffset);
 170                 *len = le32_to_cpu(((struct smb2_ioctl_req *)hdr)->InputCount);
 171                 break;
 172         default:
 173                 ksmbd_debug(SMB, "no length check for command\n");
 174                 break;
 175         }
 176
 177         if (*off > 4096) {
 178                 ksmbd_debug(SMB, "offset %d too large\n", *off);
 179                 ret = -EINVAL;
 180         } else if ((u64)*off + *len > MAX_STREAM_PROT_LEN) {
 181                 ksmbd_debug(SMB, "Request is larger than maximum stream protocol length(%u): %llu\n",
 182                             MAX_STREAM_PROT_LEN, (u64)*off + *len);
 183                 ret = -EINVAL;
 184         }
 185
 186         return ret;
 187 }
 188
 189 /*
 190  * Calculate the size of the SMB message based on the fixed header
 191  * portion, the number of word parameters and the data portion of the message.
 192  */
 193 static int smb2_calc_size(void *buf, unsigned int *len)
 194 {
 195         struct smb2_pdu *pdu = (struct smb2_pdu *)buf;
 196         struct smb2_hdr *hdr = &pdu->hdr;
 197         unsigned int offset; /* the offset from the beginning of SMB to data area */
 198         unsigned int data_length; /* the length of the variable length data area */
 199         int ret;
 200
 201         /* Structure Size has already been checked to make sure it is 64 */
 202         *len = le16_to_cpu(hdr->StructureSize);
 203
 204         /*
 205          * StructureSize2, ie length of fixed parameter area has already
 206          * been checked to make sure it is the correct length.
 207          */
 208         *len += le16_to_cpu(pdu->StructureSize2);
 209         /*
 210          * StructureSize2 of smb2_lock pdu is set to 48, indicating
 211          * the size of smb2 lock request with single smb2_lock_element
 212          * regardless of number of locks. Subtract single
 213          * smb2_lock_element for correct buffer size check.
 214          */
 215         if (hdr->Command == SMB2_LOCK)
 216                 *len -= sizeof(struct smb2_lock_element);
 217
 218         if (has_smb2_data_area[le16_to_cpu(hdr->Command)] == false)
 219                 goto calc_size_exit;
 220
 221         ret = smb2_get_data_area_len(&offset, &data_length, hdr);
 222         if (ret)
 223                 return ret;
 224         ksmbd_debug(SMB, "SMB2 data length %u offset %u\n", data_length,
 225                     offset);
 226
 227         if (data_length > 0) {
 228                 /*
 229                  * Check to make sure that data area begins after fixed area,
 230                  * Note that last byte of the fixed area is part of data area
 231                  * for some commands, typically those with odd StructureSize,
 232                  * so we must add one to the calculation.
 233                  */
 234                 if (offset + 1 < *len) {
 235                         ksmbd_debug(SMB,
 236                                     "data area offset %d overlaps SMB2 header %u\n",
 237                                     offset + 1, *len);
 238                         return -EINVAL;
 239                 }
 240
 241                 *len = offset + data_length;
 242         }
 243
 244 calc_size_exit:
 245         ksmbd_debug(SMB, "SMB2 len %u\n", *len);
 246         return 0;
 247 }
 248
 249 static inline int smb2_query_info_req_len(struct smb2_query_info_req *h)
 250 {
 251         return le32_to_cpu(h->InputBufferLength) +
 252                 le32_to_cpu(h->OutputBufferLength);
 253 }
 254
 255 static inline int smb2_set_info_req_len(struct smb2_set_info_req *h)
 256 {
 257         return le32_to_cpu(h->BufferLength);
 258 }
 259
 260 static inline int smb2_read_req_len(struct smb2_read_req *h)
 261 {
 262         return le32_to_cpu(h->Length);
 263 }
 264
 265 static inline int smb2_write_req_len(struct smb2_write_req *h)
 266 {
 267         return le32_to_cpu(h->Length);
 268 }
 269
 270 static inline int smb2_query_dir_req_len(struct smb2_query_directory_req *h)
 271 {
 272         return le32_to_cpu(h->OutputBufferLength);
 273 }
 274
 275 static inline int smb2_ioctl_req_len(struct smb2_ioctl_req *h)
 276 {
 277         return le32_to_cpu(h->InputCount) +
 278                 le32_to_cpu(h->OutputCount);
 279 }
 280
 281 static inline int smb2_ioctl_resp_len(struct smb2_ioctl_req *h)
 282 {
 283         return le32_to_cpu(h->MaxInputResponse) +
 284                 le32_to_cpu(h->MaxOutputResponse);
 285 }
 286
 287 static int smb2_validate_credit_charge(struct ksmbd_conn *conn,
 288                                        struct smb2_hdr *hdr)
 289 {
 290         unsigned int req_len = 0, expect_resp_len = 0, calc_credit_num, max_len;
 291         unsigned short credit_charge = le16_to_cpu(hdr->CreditCharge);
 292         void *__hdr = hdr;
 293         int ret;
 294
 295         switch (hdr->Command) {
 296         case SMB2_QUERY_INFO:
 297                 req_len = smb2_query_info_req_len(__hdr);
 298                 break;
 299         case SMB2_SET_INFO:
 300                 req_len = smb2_set_info_req_len(__hdr);
 301                 break;
 302         case SMB2_READ:
 303                 req_len = smb2_read_req_len(__hdr);
 304                 break;
 305         case SMB2_WRITE:
 306                 req_len = smb2_write_req_len(__hdr);
 307                 break;
 308         case SMB2_QUERY_DIRECTORY:
 309                 req_len = smb2_query_dir_req_len(__hdr);
 310                 break;
 311         case SMB2_IOCTL:
 312                 req_len = smb2_ioctl_req_len(__hdr);
 313                 expect_resp_len = smb2_ioctl_resp_len(__hdr);
 314                 break;
 315         case SMB2_CANCEL:
 316                 return 0;
 317         default:
 318                 req_len = 1;
 319                 break;
 320         }
 321
 322         credit_charge = max_t(unsigned short, credit_charge, 1);
 323         max_len = max_t(unsigned int, req_len, expect_resp_len);
 324         calc_credit_num = DIV_ROUND_UP(max_len, SMB2_MAX_BUFFER_SIZE);
 325
 326         if (credit_charge < calc_credit_num) {
 327                 ksmbd_debug(SMB, "Insufficient credit charge, given: %d, needed: %d\n",
 328                             credit_charge, calc_credit_num);
 329                 return 1;
 330         } else if (credit_charge > conn->max_credits) {
 331                 ksmbd_debug(SMB, "Too large credit charge: %d\n", credit_charge);
 332                 return 1;
 333         }
 334
 335         spin_lock(&conn->credits_lock);
 336         if (credit_charge <= conn->total_credits) {
 337                 conn->total_credits -= credit_charge;
 338                 ret = 0;
 339         } else {
 340                 ksmbd_debug(SMB, "Insufficient credits granted, given: %u, granted: %u\n",
 341                             credit_charge, conn->total_credits);
 342                 ret = 1;
 343         }
 344         spin_unlock(&conn->credits_lock);
 345         return ret;
 346 }
 347
 348 int ksmbd_smb2_check_message(struct ksmbd_work *work)
 349 {
 350         struct smb2_pdu *pdu = work->request_buf;
 351         struct smb2_hdr *hdr = &pdu->hdr;
 352         int command;
 353         __u32 clc_len;  /* calculated length */
 354         __u32 len = get_rfc1002_len(pdu);
 355
 356         if (work->next_smb2_rcv_hdr_off) {
 357                 pdu = ksmbd_req_buf_next(work);
 358                 hdr = &pdu->hdr;
 359         }
 360
 361         if (le32_to_cpu(hdr->NextCommand) > 0) {
 362                 len = le32_to_cpu(hdr->NextCommand);
 363         } else if (work->next_smb2_rcv_hdr_off) {
 364                 len -= work->next_smb2_rcv_hdr_off;
 365                 len = round_up(len, 8);
 366         }
 367
 368         if (check_smb2_hdr(hdr))
 369                 return 1;
 370
 371         if (hdr->StructureSize != SMB2_HEADER_STRUCTURE_SIZE) {
 372                 ksmbd_debug(SMB, "Illegal structure size %u\n",
 373                             le16_to_cpu(hdr->StructureSize));
 374                 return 1;
 375         }
 376
 377         command = le16_to_cpu(hdr->Command);
 378         if (command >= NUMBER_OF_SMB2_COMMANDS) {
 379                 ksmbd_debug(SMB, "Illegal SMB2 command %d\n", command);
 380                 return 1;
 381         }
 382
 383         if (smb2_req_struct_sizes[command] != pdu->StructureSize2) {
 384                 if (command != SMB2_OPLOCK_BREAK_HE &&
 385                     (hdr->Status == 0 || pdu->StructureSize2 != SMB2_ERROR_STRUCTURE_SIZE2_LE)) {
 386                         /* error packets have 9 byte structure size */
 387                         ksmbd_debug(SMB,
 388                                     "Illegal request size %u for command %d\n",
 389                                     le16_to_cpu(pdu->StructureSize2), command);
 390                         return 1;
 391                 } else if (command == SMB2_OPLOCK_BREAK_HE &&
 392                            hdr->Status == 0 &&
 393                            le16_to_cpu(pdu->StructureSize2) != OP_BREAK_STRUCT_SIZE_20 &&
 394                            le16_to_cpu(pdu->StructureSize2) != OP_BREAK_STRUCT_SIZE_21) {
 395                         /* special case for SMB2.1 lease break message */
 396                         ksmbd_debug(SMB,
 397                                     "Illegal request size %d for oplock break\n",
 398                                     le16_to_cpu(pdu->StructureSize2));
 399                         return 1;
 400                 }
 401         }
 402
 403         if (smb2_calc_size(hdr, &clc_len))
 404                 return 1;
 405
 406         if (len != clc_len) {
 407                 /* client can return one byte more due to implied bcc[0] */
 408                 if (clc_len == len + 1)
 409                         goto validate_credit;
 410
 411                 /*
 412                  * Some windows servers (win2016) will pad also the final
 413                  * PDU in a compound to 8 bytes.
 414                  */
 415                 if (ALIGN(clc_len, 8) == len)
 416                         goto validate_credit;
 417
 418                 /*
 419                  * windows client also pad up to 8 bytes when compounding.
 420                  * If pad is longer than eight bytes, log the server behavior
 421                  * (once), since may indicate a problem but allow it and
 422                  * continue since the frame is parseable.
 423                  */
 424                 if (clc_len < len) {
 425                         ksmbd_debug(SMB,
 426                                     "cli req padded more than expected. Length %d not %d for cmd:%d mid:%llu\n",
 427                                     len, clc_len, command,
 428                                     le64_to_cpu(hdr->MessageId));
 429                         goto validate_credit;
 430                 }
 431
 432                 ksmbd_debug(SMB,
 433                             "cli req too short, len %d not %d. cmd:%d mid:%llu\n",
 434                             len, clc_len, command,
 435                             le64_to_cpu(hdr->MessageId));
 436
 437                 return 1;
 438         }
 439
 440 validate_credit:
 441         if ((work->conn->vals->capabilities & SMB2_GLOBAL_CAP_LARGE_MTU) &&
 442             smb2_validate_credit_charge(work->conn, hdr)) {
 443                 work->conn->ops->set_rsp_status(work, STATUS_INVALID_PARAMETER);
 444                 return 1;
 445         }
 446
 447         return 0;
 448 }
 449
 450 int smb2_negotiate_request(struct ksmbd_work *work)
 451 {
 452         return ksmbd_smb_negotiate_common(work, SMB2_NEGOTIATE_HE);
 453 }