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