474 lines · c
1// SPDX-License-Identifier: GPL-2.0-or-later2/*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 "../common/smb2status.h"11#include "mgmt/user_session.h"12#include "connection.h"13 14static 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 requests26 * 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 is29 * indexed by command in host byte order30 */31static 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 fields56 * located in different fields for various SMB2 requests. SMB2 requests57 * with no variable length info, show an offset of zero for the offset field.58 */59static 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 */ false79};80 81/*82 * Set length of the data area and the offset to arguments.83 * if they are invalid, return error.84 */85static 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 location95 * of the data buffer offset and data buffer length for the particular96 * 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 header205 * portion, the number of word parameters and the data portion of the message.206 */207static 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 already220 * 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, indicating225 * the size of smb2 lock request with single smb2_lock_element226 * regardless of number of locks. Subtract single227 * 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 area245 * 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 258calc_size_exit:259 ksmbd_debug(SMB, "SMB2 len %u\n", *len);260 return 0;261}262 263static 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 269static inline int smb2_set_info_req_len(struct smb2_set_info_req *h)270{271 return le32_to_cpu(h->BufferLength);272}273 274static inline int smb2_read_req_len(struct smb2_read_req *h)275{276 return le32_to_cpu(h->Length);277}278 279static inline int smb2_write_req_len(struct smb2_write_req *h)280{281 return le32_to_cpu(h->Length);282}283 284static inline int smb2_query_dir_req_len(struct smb2_query_directory_req *h)285{286 return le32_to_cpu(h->OutputBufferLength);287}288 289static 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 295static 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 301static 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 } else361 conn->outstanding_credits += credit_charge;362 363 spin_unlock(&conn->credits_lock);364 365 return ret;366}367 368int 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 final433 * 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 message440 * 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 sometimes448 * sending messages where the cls_len is exactly449 * 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 462validate_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 470int smb2_negotiate_request(struct ksmbd_work *work)471{472 return ksmbd_smb_negotiate_common(work, SMB2_NEGOTIATE_HE);473}474