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 = max_t(unsigned short int, 105 le16_to_cpu(((struct smb2_tree_connect_req *)hdr)->PathOffset), 106 offsetof(struct smb2_tree_connect_req, Buffer)); 107 *len = le16_to_cpu(((struct smb2_tree_connect_req *)hdr)->PathLength); 108 break; 109 case SMB2_CREATE: 110 { 111 unsigned short int name_off = 112 max_t(unsigned short int, 113 le16_to_cpu(((struct smb2_create_req *)hdr)->NameOffset), 114 offsetof(struct smb2_create_req, Buffer)); 115 unsigned short int name_len = 116 le16_to_cpu(((struct smb2_create_req *)hdr)->NameLength); 117 118 if (((struct smb2_create_req *)hdr)->CreateContextsLength) { 119 *off = le32_to_cpu(((struct smb2_create_req *) 120 hdr)->CreateContextsOffset); 121 *len = le32_to_cpu(((struct smb2_create_req *) 122 hdr)->CreateContextsLength); 123 if (!name_len) 124 break; 125 126 if (name_off + name_len < (u64)*off + *len) 127 break; 128 } 129 130 *off = name_off; 131 *len = name_len; 132 break; 133 } 134 case SMB2_QUERY_INFO: 135 *off = max_t(unsigned int, 136 le16_to_cpu(((struct smb2_query_info_req *)hdr)->InputBufferOffset), 137 offsetof(struct smb2_query_info_req, Buffer)); 138 *len = le32_to_cpu(((struct smb2_query_info_req *)hdr)->InputBufferLength); 139 break; 140 case SMB2_SET_INFO: 141 *off = max_t(unsigned int, 142 le16_to_cpu(((struct smb2_set_info_req *)hdr)->BufferOffset), 143 offsetof(struct smb2_set_info_req, Buffer)); 144 *len = le32_to_cpu(((struct smb2_set_info_req *)hdr)->BufferLength); 145 break; 146 case SMB2_READ: 147 *off = le16_to_cpu(((struct smb2_read_req *)hdr)->ReadChannelInfoOffset); 148 *len = le16_to_cpu(((struct smb2_read_req *)hdr)->ReadChannelInfoLength); 149 break; 150 case SMB2_WRITE: 151 if (((struct smb2_write_req *)hdr)->DataOffset || 152 ((struct smb2_write_req *)hdr)->Length) { 153 *off = max_t(unsigned short int, 154 le16_to_cpu(((struct smb2_write_req *)hdr)->DataOffset), 155 offsetof(struct smb2_write_req, Buffer)); 156 *len = le32_to_cpu(((struct smb2_write_req *)hdr)->Length); 157 break; 158 } 159 160 *off = le16_to_cpu(((struct smb2_write_req *)hdr)->WriteChannelInfoOffset); 161 *len = le16_to_cpu(((struct smb2_write_req *)hdr)->WriteChannelInfoLength); 162 break; 163 case SMB2_QUERY_DIRECTORY: 164 *off = max_t(unsigned short int, 165 le16_to_cpu(((struct smb2_query_directory_req *)hdr)->FileNameOffset), 166 offsetof(struct smb2_query_directory_req, Buffer)); 167 *len = le16_to_cpu(((struct smb2_query_directory_req *)hdr)->FileNameLength); 168 break; 169 case SMB2_LOCK: 170 { 171 unsigned short lock_count; 172 173 lock_count = le16_to_cpu(((struct smb2_lock_req *)hdr)->LockCount); 174 if (lock_count > 0) { 175 *off = offsetof(struct smb2_lock_req, locks); 176 *len = sizeof(struct smb2_lock_element) * lock_count; 177 } 178 break; 179 } 180 case SMB2_IOCTL: 181 *off = max_t(unsigned int, 182 le32_to_cpu(((struct smb2_ioctl_req *)hdr)->InputOffset), 183 offsetof(struct smb2_ioctl_req, Buffer)); 184 *len = le32_to_cpu(((struct smb2_ioctl_req *)hdr)->InputCount); 185 break; 186 default: 187 ksmbd_debug(SMB, "no length check for command\n"); 188 break; 189 } 190 191 if (*off > 4096) { 192 ksmbd_debug(SMB, "offset %d too large\n", *off); 193 ret = -EINVAL; 194 } else if ((u64)*off + *len > MAX_STREAM_PROT_LEN) { 195 ksmbd_debug(SMB, "Request is larger than maximum stream protocol length(%u): %llu\n", 196 MAX_STREAM_PROT_LEN, (u64)*off + *len); 197 ret = -EINVAL; 198 } 199 200 return ret; 201 } 202 203 /* 204 * Calculate the size of the SMB message based on the fixed header 205 * portion, the number of word parameters and the data portion of the message. 206 */ 207 static int smb2_calc_size(void *buf, unsigned int *len) 208 { 209 struct smb2_pdu *pdu = (struct smb2_pdu *)buf; 210 struct smb2_hdr *hdr = &pdu->hdr; 211 unsigned int offset; /* the offset from the beginning of SMB to data area */ 212 unsigned int data_length; /* the length of the variable length data area */ 213 int ret; 214 215 /* Structure Size has already been checked to make sure it is 64 */ 216 *len = le16_to_cpu(hdr->StructureSize); 217 218 /* 219 * StructureSize2, ie length of fixed parameter area has already 220 * been checked to make sure it is the correct length. 221 */ 222 *len += le16_to_cpu(pdu->StructureSize2); 223 /* 224 * StructureSize2 of smb2_lock pdu is set to 48, indicating 225 * the size of smb2 lock request with single smb2_lock_element 226 * regardless of number of locks. Subtract single 227 * smb2_lock_element for correct buffer size check. 228 */ 229 if (hdr->Command == SMB2_LOCK) 230 *len -= sizeof(struct smb2_lock_element); 231 232 if (has_smb2_data_area[le16_to_cpu(hdr->Command)] == false) 233 goto calc_size_exit; 234 235 ret = smb2_get_data_area_len(&offset, &data_length, hdr); 236 if (ret) 237 return ret; 238 ksmbd_debug(SMB, "SMB2 data length %u offset %u\n", data_length, 239 offset); 240 241 if (data_length > 0) { 242 /* 243 * Check to make sure that data area begins after fixed area, 244 * Note that last byte of the fixed area is part of data area 245 * for some commands, typically those with odd StructureSize, 246 * so we must add one to the calculation. 247 */ 248 if (offset + 1 < *len) { 249 ksmbd_debug(SMB, 250 "data area offset %d overlaps SMB2 header %u\n", 251 offset + 1, *len); 252 return -EINVAL; 253 } 254 255 *len = offset + data_length; 256 } 257 258 calc_size_exit: 259 ksmbd_debug(SMB, "SMB2 len %u\n", *len); 260 return 0; 261 } 262 263 static inline int smb2_query_info_req_len(struct smb2_query_info_req *h) 264 { 265 return le32_to_cpu(h->InputBufferLength) + 266 le32_to_cpu(h->OutputBufferLength); 267 } 268 269 static inline int smb2_set_info_req_len(struct smb2_set_info_req *h) 270 { 271 return le32_to_cpu(h->BufferLength); 272 } 273 274 static inline int smb2_read_req_len(struct smb2_read_req *h) 275 { 276 return le32_to_cpu(h->Length); 277 } 278 279 static inline int smb2_write_req_len(struct smb2_write_req *h) 280 { 281 return le32_to_cpu(h->Length); 282 } 283 284 static inline int smb2_query_dir_req_len(struct smb2_query_directory_req *h) 285 { 286 return le32_to_cpu(h->OutputBufferLength); 287 } 288 289 static inline int smb2_ioctl_req_len(struct smb2_ioctl_req *h) 290 { 291 return le32_to_cpu(h->InputCount) + 292 le32_to_cpu(h->OutputCount); 293 } 294 295 static inline int smb2_ioctl_resp_len(struct smb2_ioctl_req *h) 296 { 297 return le32_to_cpu(h->MaxInputResponse) + 298 le32_to_cpu(h->MaxOutputResponse); 299 } 300 301 static int smb2_validate_credit_charge(struct ksmbd_conn *conn, 302 struct smb2_hdr *hdr) 303 { 304 unsigned int req_len = 0, expect_resp_len = 0, calc_credit_num, max_len; 305 unsigned short credit_charge = le16_to_cpu(hdr->CreditCharge); 306 void *__hdr = hdr; 307 int ret = 0; 308 309 switch (hdr->Command) { 310 case SMB2_QUERY_INFO: 311 req_len = smb2_query_info_req_len(__hdr); 312 break; 313 case SMB2_SET_INFO: 314 req_len = smb2_set_info_req_len(__hdr); 315 break; 316 case SMB2_READ: 317 req_len = smb2_read_req_len(__hdr); 318 break; 319 case SMB2_WRITE: 320 req_len = smb2_write_req_len(__hdr); 321 break; 322 case SMB2_QUERY_DIRECTORY: 323 req_len = smb2_query_dir_req_len(__hdr); 324 break; 325 case SMB2_IOCTL: 326 req_len = smb2_ioctl_req_len(__hdr); 327 expect_resp_len = smb2_ioctl_resp_len(__hdr); 328 break; 329 case SMB2_CANCEL: 330 return 0; 331 default: 332 req_len = 1; 333 break; 334 } 335 336 credit_charge = max_t(unsigned short, credit_charge, 1); 337 max_len = max_t(unsigned int, req_len, expect_resp_len); 338 calc_credit_num = DIV_ROUND_UP(max_len, SMB2_MAX_BUFFER_SIZE); 339 340 if (credit_charge < calc_credit_num) { 341 ksmbd_debug(SMB, "Insufficient credit charge, given: %d, needed: %d\n", 342 credit_charge, calc_credit_num); 343 return 1; 344 } else if (credit_charge > conn->vals->max_credits) { 345 ksmbd_debug(SMB, "Too large credit charge: %d\n", credit_charge); 346 return 1; 347 } 348 349 spin_lock(&conn->credits_lock); 350 if (credit_charge > conn->total_credits) { 351 ksmbd_debug(SMB, "Insufficient credits granted, given: %u, granted: %u\n", 352 credit_charge, conn->total_credits); 353 ret = 1; 354 } 355 356 if ((u64)conn->outstanding_credits + credit_charge > conn->total_credits) { 357 ksmbd_debug(SMB, "Limits exceeding the maximum allowable outstanding requests, given : %u, pending : %u\n", 358 credit_charge, conn->outstanding_credits); 359 ret = 1; 360 } else 361 conn->outstanding_credits += credit_charge; 362 363 spin_unlock(&conn->credits_lock); 364 365 return ret; 366 } 367 368 int ksmbd_smb2_check_message(struct ksmbd_work *work) 369 { 370 struct smb2_pdu *pdu = ksmbd_req_buf_next(work); 371 struct smb2_hdr *hdr = &pdu->hdr; 372 int command; 373 __u32 clc_len; /* calculated length */ 374 __u32 len = get_rfc1002_len(work->request_buf); 375 __u32 req_struct_size, next_cmd = le32_to_cpu(hdr->NextCommand); 376 377 if ((u64)work->next_smb2_rcv_hdr_off + next_cmd > len) { 378 pr_err("next command(%u) offset exceeds smb msg size\n", 379 next_cmd); 380 return 1; 381 } 382 383 if (next_cmd > 0) 384 len = next_cmd; 385 else if (work->next_smb2_rcv_hdr_off) 386 len -= work->next_smb2_rcv_hdr_off; 387 388 if (check_smb2_hdr(hdr)) 389 return 1; 390 391 if (hdr->StructureSize != SMB2_HEADER_STRUCTURE_SIZE) { 392 ksmbd_debug(SMB, "Illegal structure size %u\n", 393 le16_to_cpu(hdr->StructureSize)); 394 return 1; 395 } 396 397 command = le16_to_cpu(hdr->Command); 398 if (command >= NUMBER_OF_SMB2_COMMANDS) { 399 ksmbd_debug(SMB, "Illegal SMB2 command %d\n", command); 400 return 1; 401 } 402 403 if (smb2_req_struct_sizes[command] != pdu->StructureSize2) { 404 if (!(command == SMB2_OPLOCK_BREAK_HE && 405 (le16_to_cpu(pdu->StructureSize2) == OP_BREAK_STRUCT_SIZE_20 || 406 le16_to_cpu(pdu->StructureSize2) == OP_BREAK_STRUCT_SIZE_21))) { 407 /* special case for SMB2.1 lease break message */ 408 ksmbd_debug(SMB, 409 "Illegal request size %u for command %d\n", 410 le16_to_cpu(pdu->StructureSize2), command); 411 return 1; 412 } 413 } 414 415 req_struct_size = le16_to_cpu(pdu->StructureSize2) + 416 __SMB2_HEADER_STRUCTURE_SIZE; 417 if (command == SMB2_LOCK_HE) 418 req_struct_size -= sizeof(struct smb2_lock_element); 419 420 if (req_struct_size > len + 1) 421 return 1; 422 423 if (smb2_calc_size(hdr, &clc_len)) 424 return 1; 425 426 if (len != clc_len) { 427 /* client can return one byte more due to implied bcc[0] */ 428 if (clc_len == len + 1) 429 goto validate_credit; 430 431 /* 432 * Some windows servers (win2016) will pad also the final 433 * PDU in a compound to 8 bytes. 434 */ 435 if (ALIGN(clc_len, 8) == len) 436 goto validate_credit; 437 438 /* 439 * SMB2 NEGOTIATE request will be validated when message 440 * handling proceeds. 441 */ 442 if (command == SMB2_NEGOTIATE_HE) 443 goto validate_credit; 444 445 /* 446 * Allow a message that padded to 8byte boundary. 447 * Linux 4.19.217 with smb 3.0.2 are sometimes 448 * sending messages where the cls_len is exactly 449 * 8 bytes less than len. 450 */ 451 if (clc_len < len && (len - clc_len) <= 8) 452 goto validate_credit; 453 454 pr_err_ratelimited( 455 "cli req too short, len %d not %d. cmd:%d mid:%llu\n", 456 len, clc_len, command, 457 le64_to_cpu(hdr->MessageId)); 458 459 return 1; 460 } 461 462 validate_credit: 463 if ((work->conn->vals->capabilities & SMB2_GLOBAL_CAP_LARGE_MTU) && 464 smb2_validate_credit_charge(work->conn, hdr)) 465 return 1; 466 467 return 0; 468 } 469 470 int smb2_negotiate_request(struct ksmbd_work *work) 471 { 472 return ksmbd_smb_negotiate_common(work, SMB2_NEGOTIATE_HE); 473 } 474