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 } 462