smb/server/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                 unsigned short int name_off =
 110                         le16_to_cpu(((struct smb2_create_req *)hdr)->NameOffset);
 111                 unsigned short int name_len =
 112                         le16_to_cpu(((struct smb2_create_req *)hdr)->NameLength);
 113
 114                 if (((struct smb2_create_req *)hdr)->CreateContextsLength) {
 115                         *off = le32_to_cpu(((struct smb2_create_req *)
 116                                 hdr)->CreateContextsOffset);
 117                         *len = le32_to_cpu(((struct smb2_create_req *)
 118                                 hdr)->CreateContextsLength);
 119                         if (!name_len)
 120                                 break;
 121
 122                         if (name_off + name_len < (u64)*off + *len)
 123                                 break;
 124                 }
 125
 126                 *off = name_off;
 127                 *len = name_len;
 128                 break;
 129         }
 130         case SMB2_QUERY_INFO:
 131                 *off = le16_to_cpu(((struct smb2_query_info_req *)hdr)->InputBufferOffset);
 132                 *len = le32_to_cpu(((struct smb2_query_info_req *)hdr)->InputBufferLength);
 133                 break;
 134         case SMB2_SET_INFO:
 135                 *off = le16_to_cpu(((struct smb2_set_info_req *)hdr)->BufferOffset);
 136                 *len = le32_to_cpu(((struct smb2_set_info_req *)hdr)->BufferLength);
 137                 break;
 138         case SMB2_READ:
 139                 *off = le16_to_cpu(((struct smb2_read_req *)hdr)->ReadChannelInfoOffset);
 140                 *len = le16_to_cpu(((struct smb2_read_req *)hdr)->ReadChannelInfoLength);
 141                 break;
 142         case SMB2_WRITE:
 143                 if (((struct smb2_write_req *)hdr)->DataOffset ||
 144                     ((struct smb2_write_req *)hdr)->Length) {
 145                         *off = max_t(unsigned int,
 146                                      le16_to_cpu(((struct smb2_write_req *)hdr)->DataOffset),
 147                                      offsetof(struct smb2_write_req, Buffer));
 148                         *len = le32_to_cpu(((struct smb2_write_req *)hdr)->Length);
 149                         break;
 150                 }
 151
 152                 *off = le16_to_cpu(((struct smb2_write_req *)hdr)->WriteChannelInfoOffset);
 153                 *len = le16_to_cpu(((struct smb2_write_req *)hdr)->WriteChannelInfoLength);
 154                 break;
 155         case SMB2_QUERY_DIRECTORY:
 156                 *off = le16_to_cpu(((struct smb2_query_directory_req *)hdr)->FileNameOffset);
 157                 *len = le16_to_cpu(((struct smb2_query_directory_req *)hdr)->FileNameLength);
 158                 break;
 159         case SMB2_LOCK:
 160         {
 161                 unsigned short lock_count;
 162
 163                 lock_count = le16_to_cpu(((struct smb2_lock_req *)hdr)->LockCount);
 164                 if (lock_count > 0) {
 165                         *off = offsetof(struct smb2_lock_req, locks);
 166                         *len = sizeof(struct smb2_lock_element) * lock_count;
 167                 }
 168                 break;
 169         }
 170         case SMB2_IOCTL:
 171                 *off = le32_to_cpu(((struct smb2_ioctl_req *)hdr)->InputOffset);
 172                 *len = le32_to_cpu(((struct smb2_ioctl_req *)hdr)->InputCount);
 173                 break;
 174         default:
 175                 ksmbd_debug(SMB, "no length check for command\n");
 176                 break;
 177         }
 178
 179         if (*off > 4096) {
 180                 ksmbd_debug(SMB, "offset %d too large\n", *off);
 181                 ret = -EINVAL;
 182         } else if ((u64)*off + *len > MAX_STREAM_PROT_LEN) {
 183                 ksmbd_debug(SMB, "Request is larger than maximum stream protocol length(%u): %llu\n",
 184                             MAX_STREAM_PROT_LEN, (u64)*off + *len);
 185                 ret = -EINVAL;
 186         }
 187
 188         return ret;
 189 }
 190
 191 /*
 192  * Calculate the size of the SMB message based on the fixed header
 193  * portion, the number of word parameters and the data portion of the message.
 194  */
 195 static int smb2_calc_size(void *buf, unsigned int *len)
 196 {
 197         struct smb2_pdu *pdu = (struct smb2_pdu *)buf;
 198         struct smb2_hdr *hdr = &pdu->hdr;
 199         unsigned int offset; /* the offset from the beginning of SMB to data area */
 200         unsigned int data_length; /* the length of the variable length data area */
 201         int ret;
 202
 203         /* Structure Size has already been checked to make sure it is 64 */
 204         *len = le16_to_cpu(hdr->StructureSize);
 205
 206         /*
 207          * StructureSize2, ie length of fixed parameter area has already
 208          * been checked to make sure it is the correct length.
 209          */
 210         *len += le16_to_cpu(pdu->StructureSize2);
 211         /*
 212          * StructureSize2 of smb2_lock pdu is set to 48, indicating
 213          * the size of smb2 lock request with single smb2_lock_element
 214          * regardless of number of locks. Subtract single
 215          * smb2_lock_element for correct buffer size check.
 216          */
 217         if (hdr->Command == SMB2_LOCK)
 218                 *len -= sizeof(struct smb2_lock_element);
 219
 220         if (has_smb2_data_area[le16_to_cpu(hdr->Command)] == false)
 221                 goto calc_size_exit;
 222
 223         ret = smb2_get_data_area_len(&offset, &data_length, hdr);
 224         if (ret)
 225                 return ret;
 226         ksmbd_debug(SMB, "SMB2 data length %u offset %u\n", data_length,
 227                     offset);
 228
 229         if (data_length > 0) {
 230                 /*
 231                  * Check to make sure that data area begins after fixed area,
 232                  * Note that last byte of the fixed area is part of data area
 233                  * for some commands, typically those with odd StructureSize,
 234                  * so we must add one to the calculation.
 235                  */
 236                 if (offset + 1 < *len) {
 237                         ksmbd_debug(SMB,
 238                                     "data area offset %d overlaps SMB2 header %u\n",
 239                                     offset + 1, *len);
 240                         return -EINVAL;
 241                 }
 242
 243                 *len = offset + data_length;
 244         }
 245
 246 calc_size_exit:
 247         ksmbd_debug(SMB, "SMB2 len %u\n", *len);
 248         return 0;
 249 }
 250
 251 static inline int smb2_query_info_req_len(struct smb2_query_info_req *h)
 252 {
 253         return le32_to_cpu(h->InputBufferLength) +
 254                 le32_to_cpu(h->OutputBufferLength);
 255 }
 256
 257 static inline int smb2_set_info_req_len(struct smb2_set_info_req *h)
 258 {
 259         return le32_to_cpu(h->BufferLength);
 260 }
 261
 262 static inline int smb2_read_req_len(struct smb2_read_req *h)
 263 {
 264         return le32_to_cpu(h->Length);
 265 }
 266
 267 static inline int smb2_write_req_len(struct smb2_write_req *h)
 268 {
 269         return le32_to_cpu(h->Length);
 270 }
 271
 272 static inline int smb2_query_dir_req_len(struct smb2_query_directory_req *h)
 273 {
 274         return le32_to_cpu(h->OutputBufferLength);
 275 }
 276
 277 static inline int smb2_ioctl_req_len(struct smb2_ioctl_req *h)
 278 {
 279         return le32_to_cpu(h->InputCount) +
 280                 le32_to_cpu(h->OutputCount);
 281 }
 282
 283 static inline int smb2_ioctl_resp_len(struct smb2_ioctl_req *h)
 284 {
 285         return le32_to_cpu(h->MaxInputResponse) +
 286                 le32_to_cpu(h->MaxOutputResponse);
 287 }
 288
 289 static int smb2_validate_credit_charge(struct ksmbd_conn *conn,
 290                                        struct smb2_hdr *hdr)
 291 {
 292         unsigned int req_len = 0, expect_resp_len = 0, calc_credit_num, max_len;
 293         unsigned short credit_charge = le16_to_cpu(hdr->CreditCharge);
 294         void *__hdr = hdr;
 295         int ret = 0;
 296
 297         switch (hdr->Command) {
 298         case SMB2_QUERY_INFO:
 299                 req_len = smb2_query_info_req_len(__hdr);
 300                 break;
 301         case SMB2_SET_INFO:
 302                 req_len = smb2_set_info_req_len(__hdr);
 303                 break;
 304         case SMB2_READ:
 305                 req_len = smb2_read_req_len(__hdr);
 306                 break;
 307         case SMB2_WRITE:
 308                 req_len = smb2_write_req_len(__hdr);
 309                 break;
 310         case SMB2_QUERY_DIRECTORY:
 311                 req_len = smb2_query_dir_req_len(__hdr);
 312                 break;
 313         case SMB2_IOCTL:
 314                 req_len = smb2_ioctl_req_len(__hdr);
 315                 expect_resp_len = smb2_ioctl_resp_len(__hdr);
 316                 break;
 317         case SMB2_CANCEL:
 318                 return 0;
 319         default:
 320                 req_len = 1;
 321                 break;
 322         }
 323
 324         credit_charge = max_t(unsigned short, credit_charge, 1);
 325         max_len = max_t(unsigned int, req_len, expect_resp_len);
 326         calc_credit_num = DIV_ROUND_UP(max_len, SMB2_MAX_BUFFER_SIZE);
 327
 328         if (credit_charge < calc_credit_num) {
 329                 ksmbd_debug(SMB, "Insufficient credit charge, given: %d, needed: %d\n",
 330                             credit_charge, calc_credit_num);
 331                 return 1;
 332         } else if (credit_charge > conn->vals->max_credits) {
 333                 ksmbd_debug(SMB, "Too large credit charge: %d\n", credit_charge);
 334                 return 1;
 335         }
 336
 337         spin_lock(&conn->credits_lock);
 338         if (credit_charge > conn->total_credits) {
 339                 ksmbd_debug(SMB, "Insufficient credits granted, given: %u, granted: %u\n",
 340                             credit_charge, conn->total_credits);
 341                 ret = 1;
 342         }
 343
 344         if ((u64)conn->outstanding_credits + credit_charge > conn->total_credits) {
 345                 ksmbd_debug(SMB, "Limits exceeding the maximum allowable outstanding requests, given : %u, pending : %u\n",
 346                             credit_charge, conn->outstanding_credits);
 347                 ret = 1;
 348         } else
 349                 conn->outstanding_credits += credit_charge;
 350
 351         spin_unlock(&conn->credits_lock);
 352
 353         return ret;
 354 }
 355
 356 int ksmbd_smb2_check_message(struct ksmbd_work *work)
 357 {
 358         struct smb2_pdu *pdu = ksmbd_req_buf_next(work);
 359         struct smb2_hdr *hdr = &pdu->hdr;
 360         int command;
 361         __u32 clc_len;  /* calculated length */
 362         __u32 len = get_rfc1002_len(work->request_buf);
 363         __u32 req_struct_size, next_cmd = le32_to_cpu(hdr->NextCommand);
 364
 365         if ((u64)work->next_smb2_rcv_hdr_off + next_cmd > len) {
 366                 pr_err("next command(%u) offset exceeds smb msg size\n",
 367                                 next_cmd);
 368                 return 1;
 369         }
 370
 371         if (next_cmd > 0)
 372                 len = next_cmd;
 373         else if (work->next_smb2_rcv_hdr_off)
 374                 len -= work->next_smb2_rcv_hdr_off;
 375
 376         if (check_smb2_hdr(hdr))
 377                 return 1;
 378
 379         if (hdr->StructureSize != SMB2_HEADER_STRUCTURE_SIZE) {
 380                 ksmbd_debug(SMB, "Illegal structure size %u\n",
 381                             le16_to_cpu(hdr->StructureSize));
 382                 return 1;
 383         }
 384
 385         command = le16_to_cpu(hdr->Command);
 386         if (command >= NUMBER_OF_SMB2_COMMANDS) {
 387                 ksmbd_debug(SMB, "Illegal SMB2 command %d\n", command);
 388                 return 1;
 389         }
 390
 391         if (smb2_req_struct_sizes[command] != pdu->StructureSize2) {
 392                 if (!(command == SMB2_OPLOCK_BREAK_HE &&
 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 %u for command %d\n",
 398                                 le16_to_cpu(pdu->StructureSize2), command);
 399                         return 1;
 400                 }
 401         }
 402
 403         req_struct_size = le16_to_cpu(pdu->StructureSize2) +
 404                 __SMB2_HEADER_STRUCTURE_SIZE;
 405         if (command == SMB2_LOCK_HE)
 406                 req_struct_size -= sizeof(struct smb2_lock_element);
 407
 408         if (req_struct_size > len + 1)
 409                 return 1;
 410
 411         if (smb2_calc_size(hdr, &clc_len))
 412                 return 1;
 413
 414         if (len != clc_len) {
 415                 /* client can return one byte more due to implied bcc[0] */
 416                 if (clc_len == len + 1)
 417                         goto validate_credit;
 418
 419                 /*
 420                  * Some windows servers (win2016) will pad also the final
 421                  * PDU in a compound to 8 bytes.
 422                  */
 423                 if (ALIGN(clc_len, 8) == len)
 424                         goto validate_credit;
 425
 426                 /*
 427                  * SMB2 NEGOTIATE request will be validated when message
 428                  * handling proceeds.
 429                  */
 430                 if (command == SMB2_NEGOTIATE_HE)
 431                         goto validate_credit;
 432
 433                 /*
 434                  * Allow a message that padded to 8byte boundary.
 435                  * Linux 4.19.217 with smb 3.0.2 are sometimes
 436                  * sending messages where the cls_len is exactly
 437                  * 8 bytes less than len.
 438                  */
 439                 if (clc_len < len && (len - clc_len) <= 8)
 440                         goto validate_credit;
 441
 442                 pr_err_ratelimited(
 443                             "cli req too short, len %d not %d. cmd:%d mid:%llu\n",
 444                             len, clc_len, command,
 445                             le64_to_cpu(hdr->MessageId));
 446
 447                 return 1;
 448         }
 449
 450 validate_credit:
 451         if ((work->conn->vals->capabilities & SMB2_GLOBAL_CAP_LARGE_MTU) &&
 452             smb2_validate_credit_charge(work->conn, hdr))
 453                 return 1;
 454
 455         return 0;
 456 }
 457
 458 int smb2_negotiate_request(struct ksmbd_work *work)
 459 {
 460         return ksmbd_smb_negotiate_common(work, SMB2_NEGOTIATE_HE);
 461 }