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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
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 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 */
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 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 */
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 */ false
79};
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 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 int lock_count;
153
154 /*
155 * smb2_lock request size is 48 included single
156 * smb2_lock_element structure size.
157 */
158 lock_count = le16_to_cpu(((struct smb2_lock_req *)hdr)->LockCount) - 1;
159 if (lock_count > 0) {
160 *off = __SMB2_HEADER_STRUCTURE_SIZE + 48;
161 *len = sizeof(struct smb2_lock_element) * lock_count;
162 }
163 break;
164 }
165 case SMB2_IOCTL:
166 *off = le32_to_cpu(((struct smb2_ioctl_req *)hdr)->InputOffset);
167 *len = le32_to_cpu(((struct smb2_ioctl_req *)hdr)->InputCount);
168 break;
169 default:
170 ksmbd_debug(SMB, "no length check for command\n");
171 break;
172 }
173
174 if (*off > 4096) {
175 ksmbd_debug(SMB, "offset %d too large\n", *off);
176 ret = -EINVAL;
177 } else if ((u64)*off + *len > MAX_STREAM_PROT_LEN) {
178 ksmbd_debug(SMB, "Request is larger than maximum stream protocol length(%u): %llu\n",
179 MAX_STREAM_PROT_LEN, (u64)*off + *len);
180 ret = -EINVAL;
181 }
182
183 return ret;
184}
185
186/*
187 * Calculate the size of the SMB message based on the fixed header
188 * portion, the number of word parameters and the data portion of the message.
189 */
190static int smb2_calc_size(void *buf, unsigned int *len)
191{
192 struct smb2_pdu *pdu = (struct smb2_pdu *)buf;
193 struct smb2_hdr *hdr = &pdu->hdr;
194 unsigned int offset; /* the offset from the beginning of SMB to data area */
195 unsigned int data_length; /* the length of the variable length data area */
196 int ret;
197
198 /* Structure Size has already been checked to make sure it is 64 */
199 *len = le16_to_cpu(hdr->StructureSize);
200
201 /*
202 * StructureSize2, ie length of fixed parameter area has already
203 * been checked to make sure it is the correct length.
204 */
205 *len += le16_to_cpu(pdu->StructureSize2);
206 /*
207 * StructureSize2 of smb2_lock pdu is set to 48, indicating
208 * the size of smb2 lock request with single smb2_lock_element
209 * regardless of number of locks. Subtract single
210 * smb2_lock_element for correct buffer size check.
211 */
212 if (hdr->Command == SMB2_LOCK)
213 *len -= sizeof(struct smb2_lock_element);
214
215 if (has_smb2_data_area[le16_to_cpu(hdr->Command)] == false)
216 goto calc_size_exit;
217
218 ret = smb2_get_data_area_len(&offset, &data_length, hdr);
219 if (ret)
220 return ret;
221 ksmbd_debug(SMB, "SMB2 data length %u offset %u\n", data_length,
222 offset);
223
224 if (data_length > 0) {
225 /*
226 * Check to make sure that data area begins after fixed area,
227 * Note that last byte of the fixed area is part of data area
228 * for some commands, typically those with odd StructureSize,
229 * so we must add one to the calculation.
230 */
231 if (offset + 1 < *len) {
232 ksmbd_debug(SMB,
233 "data area offset %d overlaps SMB2 header %u\n",
234 offset + 1, *len);
235 return -EINVAL;
236 }
237
238 *len = offset + data_length;
239 }
240
241calc_size_exit:
242 ksmbd_debug(SMB, "SMB2 len %u\n", *len);
243 return 0;
244}
245
246static inline int smb2_query_info_req_len(struct smb2_query_info_req *h)
247{
248 return le32_to_cpu(h->InputBufferLength) +
249 le32_to_cpu(h->OutputBufferLength);
250}
251
252static inline int smb2_set_info_req_len(struct smb2_set_info_req *h)
253{
254 return le32_to_cpu(h->BufferLength);
255}
256
257static inline int smb2_read_req_len(struct smb2_read_req *h)
258{
259 return le32_to_cpu(h->Length);
260}
261
262static inline int smb2_write_req_len(struct smb2_write_req *h)
263{
264 return le32_to_cpu(h->Length);
265}
266
267static inline int smb2_query_dir_req_len(struct smb2_query_directory_req *h)
268{
269 return le32_to_cpu(h->OutputBufferLength);
270}
271
272static inline int smb2_ioctl_req_len(struct smb2_ioctl_req *h)
273{
274 return le32_to_cpu(h->InputCount) +
275 le32_to_cpu(h->OutputCount);
276}
277
278static inline int smb2_ioctl_resp_len(struct smb2_ioctl_req *h)
279{
280 return le32_to_cpu(h->MaxInputResponse) +
281 le32_to_cpu(h->MaxOutputResponse);
282}
283
284static int smb2_validate_credit_charge(struct ksmbd_conn *conn,
285 struct smb2_hdr *hdr)
286{
287 unsigned int req_len = 0, expect_resp_len = 0, calc_credit_num, max_len;
288 unsigned short credit_charge = le16_to_cpu(hdr->CreditCharge);
289 void *__hdr = hdr;
290 int ret = 0;
291
292 switch (hdr->Command) {
293 case SMB2_QUERY_INFO:
294 req_len = smb2_query_info_req_len(__hdr);
295 break;
296 case SMB2_SET_INFO:
297 req_len = smb2_set_info_req_len(__hdr);
298 break;
299 case SMB2_READ:
300 req_len = smb2_read_req_len(__hdr);
301 break;
302 case SMB2_WRITE:
303 req_len = smb2_write_req_len(__hdr);
304 break;
305 case SMB2_QUERY_DIRECTORY:
306 req_len = smb2_query_dir_req_len(__hdr);
307 break;
308 case SMB2_IOCTL:
309 req_len = smb2_ioctl_req_len(__hdr);
310 expect_resp_len = smb2_ioctl_resp_len(__hdr);
311 break;
312 case SMB2_CANCEL:
313 return 0;
314 default:
315 req_len = 1;
316 break;
317 }
318
319 credit_charge = max_t(unsigned short, credit_charge, 1);
320 max_len = max_t(unsigned int, req_len, expect_resp_len);
321 calc_credit_num = DIV_ROUND_UP(max_len, SMB2_MAX_BUFFER_SIZE);
322
323 if (credit_charge < calc_credit_num) {
324 ksmbd_debug(SMB, "Insufficient credit charge, given: %d, needed: %d\n",
325 credit_charge, calc_credit_num);
326 return 1;
327 } else if (credit_charge > conn->vals->max_credits) {
328 ksmbd_debug(SMB, "Too large credit charge: %d\n", credit_charge);
329 return 1;
330 }
331
332 spin_lock(&conn->credits_lock);
333 if (credit_charge > conn->total_credits) {
334 ksmbd_debug(SMB, "Insufficient credits granted, given: %u, granted: %u\n",
335 credit_charge, conn->total_credits);
336 ret = 1;
337 }
338
339 if ((u64)conn->outstanding_credits + credit_charge > conn->total_credits) {
340 ksmbd_debug(SMB, "Limits exceeding the maximum allowable outstanding requests, given : %u, pending : %u\n",
341 credit_charge, conn->outstanding_credits);
342 ret = 1;
343 } else
344 conn->outstanding_credits += credit_charge;
345
346 spin_unlock(&conn->credits_lock);
347
348 return ret;
349}
350
351int ksmbd_smb2_check_message(struct ksmbd_work *work)
352{
353 struct smb2_pdu *pdu = ksmbd_req_buf_next(work);
354 struct smb2_hdr *hdr = &pdu->hdr;
355 int command;
356 __u32 clc_len; /* calculated length */
357 __u32 len = get_rfc1002_len(work->request_buf);
358
359 if (le32_to_cpu(hdr->NextCommand) > 0)
360 len = le32_to_cpu(hdr->NextCommand);
361 else if (work->next_smb2_rcv_hdr_off)
362 len -= work->next_smb2_rcv_hdr_off;
363
364 if (check_smb2_hdr(hdr))
365 return 1;
366
367 if (hdr->StructureSize != SMB2_HEADER_STRUCTURE_SIZE) {
368 ksmbd_debug(SMB, "Illegal structure size %u\n",
369 le16_to_cpu(hdr->StructureSize));
370 return 1;
371 }
372
373 command = le16_to_cpu(hdr->Command);
374 if (command >= NUMBER_OF_SMB2_COMMANDS) {
375 ksmbd_debug(SMB, "Illegal SMB2 command %d\n", command);
376 return 1;
377 }
378
379 if (smb2_req_struct_sizes[command] != pdu->StructureSize2) {
380 if (command != SMB2_OPLOCK_BREAK_HE &&
381 (hdr->Status == 0 || pdu->StructureSize2 != SMB2_ERROR_STRUCTURE_SIZE2_LE)) {
382 /* error packets have 9 byte structure size */
383 ksmbd_debug(SMB,
384 "Illegal request size %u for command %d\n",
385 le16_to_cpu(pdu->StructureSize2), command);
386 return 1;
387 } else if (command == SMB2_OPLOCK_BREAK_HE &&
388 hdr->Status == 0 &&
389 le16_to_cpu(pdu->StructureSize2) != OP_BREAK_STRUCT_SIZE_20 &&
390 le16_to_cpu(pdu->StructureSize2) != OP_BREAK_STRUCT_SIZE_21) {
391 /* special case for SMB2.1 lease break message */
392 ksmbd_debug(SMB,
393 "Illegal request size %d for oplock break\n",
394 le16_to_cpu(pdu->StructureSize2));
395 return 1;
396 }
397 }
398
399 if (smb2_calc_size(hdr, &clc_len))
400 return 1;
401
402 if (len != clc_len) {
403 /* client can return one byte more due to implied bcc[0] */
404 if (clc_len == len + 1)
405 goto validate_credit;
406
407 /*
408 * Some windows servers (win2016) will pad also the final
409 * PDU in a compound to 8 bytes.
410 */
411 if (ALIGN(clc_len, 8) == len)
412 goto validate_credit;
413
414 /*
415 * windows client also pad up to 8 bytes when compounding.
416 * If pad is longer than eight bytes, log the server behavior
417 * (once), since may indicate a problem but allow it and
418 * continue since the frame is parseable.
419 */
420 if (clc_len < len) {
421 ksmbd_debug(SMB,
422 "cli req padded more than expected. Length %d not %d for cmd:%d mid:%llu\n",
423 len, clc_len, command,
424 le64_to_cpu(hdr->MessageId));
425 goto validate_credit;
426 }
427
428 ksmbd_debug(SMB,
429 "cli req too short, len %d not %d. cmd:%d mid:%llu\n",
430 len, clc_len, command,
431 le64_to_cpu(hdr->MessageId));
432
433 return 1;
434 }
435
436validate_credit:
437 if ((work->conn->vals->capabilities & SMB2_GLOBAL_CAP_LARGE_MTU) &&
438 smb2_validate_credit_charge(work->conn, hdr)) {
439 work->conn->ops->set_rsp_status(work, STATUS_INVALID_PARAMETER);
440 return 1;
441 }
442
443 return 0;
444}
445
446int smb2_negotiate_request(struct ksmbd_work *work)
447{
448 return ksmbd_smb_negotiate_common(work, SMB2_NEGOTIATE_HE);
449}