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 "smb2pdu.h"
10 #include "smb_common.h"
11 #include "smbstatus.h"
12 #include "mgmt/user_session.h"
13 #include "connection.h"
14
check_smb2_hdr(struct smb2_hdr * hdr)15 static int check_smb2_hdr(struct smb2_hdr *hdr)
16 {
17 /*
18 * Make sure that this really is an SMB, that it is a response.
19 */
20 if (hdr->Flags & SMB2_FLAGS_SERVER_TO_REDIR)
21 return 1;
22 return 0;
23 }
24
25 /*
26 * The following table defines the expected "StructureSize" of SMB2 requests
27 * in order by SMB2 command. This is similar to "wct" in SMB/CIFS requests.
28 *
29 * Note that commands are defined in smb2pdu.h in le16 but the array below is
30 * indexed by command in host byte order
31 */
32 static const __le16 smb2_req_struct_sizes[NUMBER_OF_SMB2_COMMANDS] = {
33 /* SMB2_NEGOTIATE */ cpu_to_le16(36),
34 /* SMB2_SESSION_SETUP */ cpu_to_le16(25),
35 /* SMB2_LOGOFF */ cpu_to_le16(4),
36 /* SMB2_TREE_CONNECT */ cpu_to_le16(9),
37 /* SMB2_TREE_DISCONNECT */ cpu_to_le16(4),
38 /* SMB2_CREATE */ cpu_to_le16(57),
39 /* SMB2_CLOSE */ cpu_to_le16(24),
40 /* SMB2_FLUSH */ cpu_to_le16(24),
41 /* SMB2_READ */ cpu_to_le16(49),
42 /* SMB2_WRITE */ cpu_to_le16(49),
43 /* SMB2_LOCK */ cpu_to_le16(48),
44 /* SMB2_IOCTL */ cpu_to_le16(57),
45 /* SMB2_CANCEL */ cpu_to_le16(4),
46 /* SMB2_ECHO */ cpu_to_le16(4),
47 /* SMB2_QUERY_DIRECTORY */ cpu_to_le16(33),
48 /* SMB2_CHANGE_NOTIFY */ cpu_to_le16(32),
49 /* SMB2_QUERY_INFO */ cpu_to_le16(41),
50 /* SMB2_SET_INFO */ cpu_to_le16(33),
51 /* use 44 for lease break */
52 /* SMB2_OPLOCK_BREAK */ cpu_to_le16(36)
53 };
54
55 /*
56 * The size of the variable area depends on the offset and length fields
57 * located in different fields for various SMB2 requests. SMB2 requests
58 * with no variable length info, show an offset of zero for the offset field.
59 */
60 static const bool has_smb2_data_area[NUMBER_OF_SMB2_COMMANDS] = {
61 /* SMB2_NEGOTIATE */ true,
62 /* SMB2_SESSION_SETUP */ true,
63 /* SMB2_LOGOFF */ false,
64 /* SMB2_TREE_CONNECT */ true,
65 /* SMB2_TREE_DISCONNECT */ false,
66 /* SMB2_CREATE */ true,
67 /* SMB2_CLOSE */ false,
68 /* SMB2_FLUSH */ false,
69 /* SMB2_READ */ true,
70 /* SMB2_WRITE */ true,
71 /* SMB2_LOCK */ true,
72 /* SMB2_IOCTL */ true,
73 /* SMB2_CANCEL */ false, /* BB CHECK this not listed in documentation */
74 /* SMB2_ECHO */ false,
75 /* SMB2_QUERY_DIRECTORY */ true,
76 /* SMB2_CHANGE_NOTIFY */ false,
77 /* SMB2_QUERY_INFO */ true,
78 /* SMB2_SET_INFO */ true,
79 /* SMB2_OPLOCK_BREAK */ false
80 };
81
82 /*
83 * Set length of the data area and the offset to arguments.
84 * if they are invalid, return error.
85 */
smb2_get_data_area_len(unsigned int * off,unsigned int * len,struct smb2_hdr * hdr)86 static int smb2_get_data_area_len(unsigned int *off, unsigned int *len,
87 struct smb2_hdr *hdr)
88 {
89 int ret = 0;
90
91 *off = 0;
92 *len = 0;
93
94 /* error reqeusts do not have data area */
95 if (hdr->Status && hdr->Status != STATUS_MORE_PROCESSING_REQUIRED &&
96 (((struct smb2_err_rsp *)hdr)->StructureSize) == SMB2_ERROR_STRUCTURE_SIZE2_LE)
97 return ret;
98
99 /*
100 * Following commands have data areas so we have to get the location
101 * of the data buffer offset and data buffer length for the particular
102 * command.
103 */
104 switch (hdr->Command) {
105 case SMB2_SESSION_SETUP:
106 *off = le16_to_cpu(((struct smb2_sess_setup_req *)hdr)->SecurityBufferOffset);
107 *len = le16_to_cpu(((struct smb2_sess_setup_req *)hdr)->SecurityBufferLength);
108 break;
109 case SMB2_TREE_CONNECT:
110 *off = le16_to_cpu(((struct smb2_tree_connect_req *)hdr)->PathOffset);
111 *len = le16_to_cpu(((struct smb2_tree_connect_req *)hdr)->PathLength);
112 break;
113 case SMB2_CREATE:
114 {
115 if (((struct smb2_create_req *)hdr)->CreateContextsLength) {
116 *off = le32_to_cpu(((struct smb2_create_req *)
117 hdr)->CreateContextsOffset);
118 *len = le32_to_cpu(((struct smb2_create_req *)
119 hdr)->CreateContextsLength);
120 break;
121 }
122
123 *off = le16_to_cpu(((struct smb2_create_req *)hdr)->NameOffset);
124 *len = le16_to_cpu(((struct smb2_create_req *)hdr)->NameLength);
125 break;
126 }
127 case SMB2_QUERY_INFO:
128 *off = le16_to_cpu(((struct smb2_query_info_req *)hdr)->InputBufferOffset);
129 *len = le32_to_cpu(((struct smb2_query_info_req *)hdr)->InputBufferLength);
130 break;
131 case SMB2_SET_INFO:
132 *off = le16_to_cpu(((struct smb2_set_info_req *)hdr)->BufferOffset);
133 *len = le32_to_cpu(((struct smb2_set_info_req *)hdr)->BufferLength);
134 break;
135 case SMB2_READ:
136 *off = le16_to_cpu(((struct smb2_read_req *)hdr)->ReadChannelInfoOffset);
137 *len = le16_to_cpu(((struct smb2_read_req *)hdr)->ReadChannelInfoLength);
138 break;
139 case SMB2_WRITE:
140 if (((struct smb2_write_req *)hdr)->DataOffset) {
141 *off = le16_to_cpu(((struct smb2_write_req *)hdr)->DataOffset);
142 *len = le32_to_cpu(((struct smb2_write_req *)hdr)->Length);
143 break;
144 }
145
146 *off = le16_to_cpu(((struct smb2_write_req *)hdr)->WriteChannelInfoOffset);
147 *len = le16_to_cpu(((struct smb2_write_req *)hdr)->WriteChannelInfoLength);
148 break;
149 case SMB2_QUERY_DIRECTORY:
150 *off = le16_to_cpu(((struct smb2_query_directory_req *)hdr)->FileNameOffset);
151 *len = le16_to_cpu(((struct smb2_query_directory_req *)hdr)->FileNameLength);
152 break;
153 case SMB2_LOCK:
154 {
155 int lock_count;
156
157 /*
158 * smb2_lock request size is 48 included single
159 * smb2_lock_element structure size.
160 */
161 lock_count = le16_to_cpu(((struct smb2_lock_req *)hdr)->LockCount) - 1;
162 if (lock_count > 0) {
163 *off = __SMB2_HEADER_STRUCTURE_SIZE + 48;
164 *len = sizeof(struct smb2_lock_element) * lock_count;
165 }
166 break;
167 }
168 case SMB2_IOCTL:
169 *off = le32_to_cpu(((struct smb2_ioctl_req *)hdr)->InputOffset);
170 *len = le32_to_cpu(((struct smb2_ioctl_req *)hdr)->InputCount);
171 break;
172 default:
173 ksmbd_debug(SMB, "no length check for command\n");
174 break;
175 }
176
177 if (*off > 4096) {
178 ksmbd_debug(SMB, "offset %d too large\n", *off);
179 ret = -EINVAL;
180 } else if ((u64)*off + *len > MAX_STREAM_PROT_LEN) {
181 ksmbd_debug(SMB, "Request is larger than maximum stream protocol length(%u): %llu\n",
182 MAX_STREAM_PROT_LEN, (u64)*off + *len);
183 ret = -EINVAL;
184 }
185
186 return ret;
187 }
188
189 /*
190 * Calculate the size of the SMB message based on the fixed header
191 * portion, the number of word parameters and the data portion of the message.
192 */
smb2_calc_size(void * buf,unsigned int * len)193 static int smb2_calc_size(void *buf, unsigned int *len)
194 {
195 struct smb2_pdu *pdu = (struct smb2_pdu *)buf;
196 struct smb2_hdr *hdr = &pdu->hdr;
197 unsigned int offset; /* the offset from the beginning of SMB to data area */
198 unsigned int data_length; /* the length of the variable length data area */
199 int ret;
200
201 /* Structure Size has already been checked to make sure it is 64 */
202 *len = le16_to_cpu(hdr->StructureSize);
203
204 /*
205 * StructureSize2, ie length of fixed parameter area has already
206 * been checked to make sure it is the correct length.
207 */
208 *len += le16_to_cpu(pdu->StructureSize2);
209 /*
210 * StructureSize2 of smb2_lock pdu is set to 48, indicating
211 * the size of smb2 lock request with single smb2_lock_element
212 * regardless of number of locks. Subtract single
213 * smb2_lock_element for correct buffer size check.
214 */
215 if (hdr->Command == SMB2_LOCK)
216 *len -= sizeof(struct smb2_lock_element);
217
218 if (has_smb2_data_area[le16_to_cpu(hdr->Command)] == false)
219 goto calc_size_exit;
220
221 ret = smb2_get_data_area_len(&offset, &data_length, hdr);
222 if (ret)
223 return ret;
224 ksmbd_debug(SMB, "SMB2 data length %u offset %u\n", data_length,
225 offset);
226
227 if (data_length > 0) {
228 /*
229 * Check to make sure that data area begins after fixed area,
230 * Note that last byte of the fixed area is part of data area
231 * for some commands, typically those with odd StructureSize,
232 * so we must add one to the calculation.
233 */
234 if (offset + 1 < *len) {
235 ksmbd_debug(SMB,
236 "data area offset %d overlaps SMB2 header %u\n",
237 offset + 1, *len);
238 return -EINVAL;
239 }
240
241 *len = offset + data_length;
242 }
243
244 calc_size_exit:
245 ksmbd_debug(SMB, "SMB2 len %u\n", *len);
246 return 0;
247 }
248
smb2_query_info_req_len(struct smb2_query_info_req * h)249 static inline int smb2_query_info_req_len(struct smb2_query_info_req *h)
250 {
251 return le32_to_cpu(h->InputBufferLength) +
252 le32_to_cpu(h->OutputBufferLength);
253 }
254
smb2_set_info_req_len(struct smb2_set_info_req * h)255 static inline int smb2_set_info_req_len(struct smb2_set_info_req *h)
256 {
257 return le32_to_cpu(h->BufferLength);
258 }
259
smb2_read_req_len(struct smb2_read_req * h)260 static inline int smb2_read_req_len(struct smb2_read_req *h)
261 {
262 return le32_to_cpu(h->Length);
263 }
264
smb2_write_req_len(struct smb2_write_req * h)265 static inline int smb2_write_req_len(struct smb2_write_req *h)
266 {
267 return le32_to_cpu(h->Length);
268 }
269
smb2_query_dir_req_len(struct smb2_query_directory_req * h)270 static inline int smb2_query_dir_req_len(struct smb2_query_directory_req *h)
271 {
272 return le32_to_cpu(h->OutputBufferLength);
273 }
274
smb2_ioctl_req_len(struct smb2_ioctl_req * h)275 static inline int smb2_ioctl_req_len(struct smb2_ioctl_req *h)
276 {
277 return le32_to_cpu(h->InputCount) +
278 le32_to_cpu(h->OutputCount);
279 }
280
smb2_ioctl_resp_len(struct smb2_ioctl_req * h)281 static inline int smb2_ioctl_resp_len(struct smb2_ioctl_req *h)
282 {
283 return le32_to_cpu(h->MaxInputResponse) +
284 le32_to_cpu(h->MaxOutputResponse);
285 }
286
smb2_validate_credit_charge(struct ksmbd_conn * conn,struct smb2_hdr * hdr)287 static int smb2_validate_credit_charge(struct ksmbd_conn *conn,
288 struct smb2_hdr *hdr)
289 {
290 unsigned int req_len = 0, expect_resp_len = 0, calc_credit_num, max_len;
291 unsigned short credit_charge = le16_to_cpu(hdr->CreditCharge);
292 void *__hdr = hdr;
293 int ret;
294
295 switch (hdr->Command) {
296 case SMB2_QUERY_INFO:
297 req_len = smb2_query_info_req_len(__hdr);
298 break;
299 case SMB2_SET_INFO:
300 req_len = smb2_set_info_req_len(__hdr);
301 break;
302 case SMB2_READ:
303 req_len = smb2_read_req_len(__hdr);
304 break;
305 case SMB2_WRITE:
306 req_len = smb2_write_req_len(__hdr);
307 break;
308 case SMB2_QUERY_DIRECTORY:
309 req_len = smb2_query_dir_req_len(__hdr);
310 break;
311 case SMB2_IOCTL:
312 req_len = smb2_ioctl_req_len(__hdr);
313 expect_resp_len = smb2_ioctl_resp_len(__hdr);
314 break;
315 case SMB2_CANCEL:
316 return 0;
317 default:
318 req_len = 1;
319 break;
320 }
321
322 credit_charge = max_t(unsigned short, credit_charge, 1);
323 max_len = max_t(unsigned int, req_len, expect_resp_len);
324 calc_credit_num = DIV_ROUND_UP(max_len, SMB2_MAX_BUFFER_SIZE);
325
326 if (credit_charge < calc_credit_num) {
327 ksmbd_debug(SMB, "Insufficient credit charge, given: %d, needed: %d\n",
328 credit_charge, calc_credit_num);
329 return 1;
330 } else if (credit_charge > conn->max_credits) {
331 ksmbd_debug(SMB, "Too large credit charge: %d\n", credit_charge);
332 return 1;
333 }
334
335 spin_lock(&conn->credits_lock);
336 if (credit_charge <= conn->total_credits) {
337 conn->total_credits -= credit_charge;
338 ret = 0;
339 } else {
340 ksmbd_debug(SMB, "Insufficient credits granted, given: %u, granted: %u\n",
341 credit_charge, conn->total_credits);
342 ret = 1;
343 }
344 spin_unlock(&conn->credits_lock);
345 return ret;
346 }
347
ksmbd_smb2_check_message(struct ksmbd_work * work)348 int ksmbd_smb2_check_message(struct ksmbd_work *work)
349 {
350 struct smb2_pdu *pdu = work->request_buf;
351 struct smb2_hdr *hdr = &pdu->hdr;
352 int command;
353 __u32 clc_len; /* calculated length */
354 __u32 len = get_rfc1002_len(pdu);
355
356 if (work->next_smb2_rcv_hdr_off) {
357 pdu = ksmbd_req_buf_next(work);
358 hdr = &pdu->hdr;
359 }
360
361 if (le32_to_cpu(hdr->NextCommand) > 0) {
362 len = le32_to_cpu(hdr->NextCommand);
363 } else if (work->next_smb2_rcv_hdr_off) {
364 len -= work->next_smb2_rcv_hdr_off;
365 len = round_up(len, 8);
366 }
367
368 if (check_smb2_hdr(hdr))
369 return 1;
370
371 if (hdr->StructureSize != SMB2_HEADER_STRUCTURE_SIZE) {
372 ksmbd_debug(SMB, "Illegal structure size %u\n",
373 le16_to_cpu(hdr->StructureSize));
374 return 1;
375 }
376
377 command = le16_to_cpu(hdr->Command);
378 if (command >= NUMBER_OF_SMB2_COMMANDS) {
379 ksmbd_debug(SMB, "Illegal SMB2 command %d\n", command);
380 return 1;
381 }
382
383 if (smb2_req_struct_sizes[command] != pdu->StructureSize2) {
384 if (command != SMB2_OPLOCK_BREAK_HE &&
385 (hdr->Status == 0 || pdu->StructureSize2 != SMB2_ERROR_STRUCTURE_SIZE2_LE)) {
386 /* error packets have 9 byte structure size */
387 ksmbd_debug(SMB,
388 "Illegal request size %u for command %d\n",
389 le16_to_cpu(pdu->StructureSize2), command);
390 return 1;
391 } else if (command == SMB2_OPLOCK_BREAK_HE &&
392 hdr->Status == 0 &&
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 %d for oplock break\n",
398 le16_to_cpu(pdu->StructureSize2));
399 return 1;
400 }
401 }
402
403 if (smb2_calc_size(hdr, &clc_len))
404 return 1;
405
406 if (len != clc_len) {
407 /* client can return one byte more due to implied bcc[0] */
408 if (clc_len == len + 1)
409 goto validate_credit;
410
411 /*
412 * Some windows servers (win2016) will pad also the final
413 * PDU in a compound to 8 bytes.
414 */
415 if (ALIGN(clc_len, 8) == len)
416 goto validate_credit;
417
418 /*
419 * windows client also pad up to 8 bytes when compounding.
420 * If pad is longer than eight bytes, log the server behavior
421 * (once), since may indicate a problem but allow it and
422 * continue since the frame is parseable.
423 */
424 if (clc_len < len) {
425 ksmbd_debug(SMB,
426 "cli req padded more than expected. Length %d not %d for cmd:%d mid:%llu\n",
427 len, clc_len, command,
428 le64_to_cpu(hdr->MessageId));
429 goto validate_credit;
430 }
431
432 ksmbd_debug(SMB,
433 "cli req too short, len %d not %d. cmd:%d mid:%llu\n",
434 len, clc_len, command,
435 le64_to_cpu(hdr->MessageId));
436
437 return 1;
438 }
439
440 validate_credit:
441 if ((work->conn->vals->capabilities & SMB2_GLOBAL_CAP_LARGE_MTU) &&
442 smb2_validate_credit_charge(work->conn, hdr)) {
443 work->conn->ops->set_rsp_status(work, STATUS_INVALID_PARAMETER);
444 return 1;
445 }
446
447 return 0;
448 }
449
smb2_negotiate_request(struct ksmbd_work * work)450 int smb2_negotiate_request(struct ksmbd_work *work)
451 {
452 return ksmbd_smb_negotiate_common(work, SMB2_NEGOTIATE_HE);
453 }
454
