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