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
check_smb2_hdr(struct smb2_hdr * hdr)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 */
smb2_get_data_area_len(unsigned int * off,unsigned int * len,struct smb2_hdr * hdr)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 /* error reqeusts do not have data area */
94 if (hdr->Status && hdr->Status != STATUS_MORE_PROCESSING_REQUIRED &&
95 (((struct smb2_err_rsp *)hdr)->StructureSize) == SMB2_ERROR_STRUCTURE_SIZE2_LE)
96 return ret;
97
98 /*
99 * Following commands have data areas so we have to get the location
100 * of the data buffer offset and data buffer length for the particular
101 * command.
102 */
103 switch (hdr->Command) {
104 case SMB2_SESSION_SETUP:
105 *off = le16_to_cpu(((struct smb2_sess_setup_req *)hdr)->SecurityBufferOffset);
106 *len = le16_to_cpu(((struct smb2_sess_setup_req *)hdr)->SecurityBufferLength);
107 break;
108 case SMB2_TREE_CONNECT:
109 *off = le16_to_cpu(((struct smb2_tree_connect_req *)hdr)->PathOffset);
110 *len = le16_to_cpu(((struct smb2_tree_connect_req *)hdr)->PathLength);
111 break;
112 case SMB2_CREATE:
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 break;
120 }
121
122 *off = le16_to_cpu(((struct smb2_create_req *)hdr)->NameOffset);
123 *len = le16_to_cpu(((struct smb2_create_req *)hdr)->NameLength);
124 break;
125 }
126 case SMB2_QUERY_INFO:
127 *off = le16_to_cpu(((struct smb2_query_info_req *)hdr)->InputBufferOffset);
128 *len = le32_to_cpu(((struct smb2_query_info_req *)hdr)->InputBufferLength);
129 break;
130 case SMB2_SET_INFO:
131 *off = le16_to_cpu(((struct smb2_set_info_req *)hdr)->BufferOffset);
132 *len = le32_to_cpu(((struct smb2_set_info_req *)hdr)->BufferLength);
133 break;
134 case SMB2_READ:
135 *off = le16_to_cpu(((struct smb2_read_req *)hdr)->ReadChannelInfoOffset);
136 *len = le16_to_cpu(((struct smb2_read_req *)hdr)->ReadChannelInfoLength);
137 break;
138 case SMB2_WRITE:
139 if (((struct smb2_write_req *)hdr)->DataOffset) {
140 *off = le16_to_cpu(((struct smb2_write_req *)hdr)->DataOffset);
141 *len = le32_to_cpu(((struct smb2_write_req *)hdr)->Length);
142 break;
143 }
144
145 *off = le16_to_cpu(((struct smb2_write_req *)hdr)->WriteChannelInfoOffset);
146 *len = le16_to_cpu(((struct smb2_write_req *)hdr)->WriteChannelInfoLength);
147 break;
148 case SMB2_QUERY_DIRECTORY:
149 *off = le16_to_cpu(((struct smb2_query_directory_req *)hdr)->FileNameOffset);
150 *len = le16_to_cpu(((struct smb2_query_directory_req *)hdr)->FileNameLength);
151 break;
152 case SMB2_LOCK:
153 {
154 int lock_count;
155
156 /*
157 * smb2_lock request size is 48 included single
158 * smb2_lock_element structure size.
159 */
160 lock_count = le16_to_cpu(((struct smb2_lock_req *)hdr)->LockCount) - 1;
161 if (lock_count > 0) {
162 *off = __SMB2_HEADER_STRUCTURE_SIZE + 48;
163 *len = sizeof(struct smb2_lock_element) * lock_count;
164 }
165 break;
166 }
167 case SMB2_IOCTL:
168 *off = le32_to_cpu(((struct smb2_ioctl_req *)hdr)->InputOffset);
169 *len = le32_to_cpu(((struct smb2_ioctl_req *)hdr)->InputCount);
170 break;
171 default:
172 ksmbd_debug(SMB, "no length check for command\n");
173 break;
174 }
175
176 if (*off > 4096) {
177 ksmbd_debug(SMB, "offset %d too large\n", *off);
178 ret = -EINVAL;
179 } else if ((u64)*off + *len > MAX_STREAM_PROT_LEN) {
180 ksmbd_debug(SMB, "Request is larger than maximum stream protocol length(%u): %llu\n",
181 MAX_STREAM_PROT_LEN, (u64)*off + *len);
182 ret = -EINVAL;
183 }
184
185 return ret;
186 }
187
188 /*
189 * Calculate the size of the SMB message based on the fixed header
190 * portion, the number of word parameters and the data portion of the message.
191 */
smb2_calc_size(void * buf,unsigned int * len)192 static int smb2_calc_size(void *buf, unsigned int *len)
193 {
194 struct smb2_pdu *pdu = (struct smb2_pdu *)buf;
195 struct smb2_hdr *hdr = &pdu->hdr;
196 unsigned int offset; /* the offset from the beginning of SMB to data area */
197 unsigned int data_length; /* the length of the variable length data area */
198 int ret;
199
200 /* Structure Size has already been checked to make sure it is 64 */
201 *len = le16_to_cpu(hdr->StructureSize);
202
203 /*
204 * StructureSize2, ie length of fixed parameter area has already
205 * been checked to make sure it is the correct length.
206 */
207 *len += le16_to_cpu(pdu->StructureSize2);
208 /*
209 * StructureSize2 of smb2_lock pdu is set to 48, indicating
210 * the size of smb2 lock request with single smb2_lock_element
211 * regardless of number of locks. Subtract single
212 * smb2_lock_element for correct buffer size check.
213 */
214 if (hdr->Command == SMB2_LOCK)
215 *len -= sizeof(struct smb2_lock_element);
216
217 if (has_smb2_data_area[le16_to_cpu(hdr->Command)] == false)
218 goto calc_size_exit;
219
220 ret = smb2_get_data_area_len(&offset, &data_length, hdr);
221 if (ret)
222 return ret;
223 ksmbd_debug(SMB, "SMB2 data length %u offset %u\n", data_length,
224 offset);
225
226 if (data_length > 0) {
227 /*
228 * Check to make sure that data area begins after fixed area,
229 * Note that last byte of the fixed area is part of data area
230 * for some commands, typically those with odd StructureSize,
231 * so we must add one to the calculation.
232 */
233 if (offset + 1 < *len) {
234 ksmbd_debug(SMB,
235 "data area offset %d overlaps SMB2 header %u\n",
236 offset + 1, *len);
237 return -EINVAL;
238 }
239
240 *len = offset + data_length;
241 }
242
243 calc_size_exit:
244 ksmbd_debug(SMB, "SMB2 len %u\n", *len);
245 return 0;
246 }
247
smb2_query_info_req_len(struct smb2_query_info_req * h)248 static inline int smb2_query_info_req_len(struct smb2_query_info_req *h)
249 {
250 return le32_to_cpu(h->InputBufferLength) +
251 le32_to_cpu(h->OutputBufferLength);
252 }
253
smb2_set_info_req_len(struct smb2_set_info_req * h)254 static inline int smb2_set_info_req_len(struct smb2_set_info_req *h)
255 {
256 return le32_to_cpu(h->BufferLength);
257 }
258
smb2_read_req_len(struct smb2_read_req * h)259 static inline int smb2_read_req_len(struct smb2_read_req *h)
260 {
261 return le32_to_cpu(h->Length);
262 }
263
smb2_write_req_len(struct smb2_write_req * h)264 static inline int smb2_write_req_len(struct smb2_write_req *h)
265 {
266 return le32_to_cpu(h->Length);
267 }
268
smb2_query_dir_req_len(struct smb2_query_directory_req * h)269 static inline int smb2_query_dir_req_len(struct smb2_query_directory_req *h)
270 {
271 return le32_to_cpu(h->OutputBufferLength);
272 }
273
smb2_ioctl_req_len(struct smb2_ioctl_req * h)274 static inline int smb2_ioctl_req_len(struct smb2_ioctl_req *h)
275 {
276 return le32_to_cpu(h->InputCount) +
277 le32_to_cpu(h->OutputCount);
278 }
279
smb2_ioctl_resp_len(struct smb2_ioctl_req * h)280 static inline int smb2_ioctl_resp_len(struct smb2_ioctl_req *h)
281 {
282 return le32_to_cpu(h->MaxInputResponse) +
283 le32_to_cpu(h->MaxOutputResponse);
284 }
285
smb2_validate_credit_charge(struct ksmbd_conn * conn,struct smb2_hdr * hdr)286 static int smb2_validate_credit_charge(struct ksmbd_conn *conn,
287 struct smb2_hdr *hdr)
288 {
289 unsigned int req_len = 0, expect_resp_len = 0, calc_credit_num, max_len;
290 unsigned short credit_charge = le16_to_cpu(hdr->CreditCharge);
291 void *__hdr = hdr;
292 int ret;
293
294 switch (hdr->Command) {
295 case SMB2_QUERY_INFO:
296 req_len = smb2_query_info_req_len(__hdr);
297 break;
298 case SMB2_SET_INFO:
299 req_len = smb2_set_info_req_len(__hdr);
300 break;
301 case SMB2_READ:
302 req_len = smb2_read_req_len(__hdr);
303 break;
304 case SMB2_WRITE:
305 req_len = smb2_write_req_len(__hdr);
306 break;
307 case SMB2_QUERY_DIRECTORY:
308 req_len = smb2_query_dir_req_len(__hdr);
309 break;
310 case SMB2_IOCTL:
311 req_len = smb2_ioctl_req_len(__hdr);
312 expect_resp_len = smb2_ioctl_resp_len(__hdr);
313 break;
314 case SMB2_CANCEL:
315 return 0;
316 default:
317 req_len = 1;
318 break;
319 }
320
321 credit_charge = max_t(unsigned short, credit_charge, 1);
322 max_len = max_t(unsigned int, req_len, expect_resp_len);
323 calc_credit_num = DIV_ROUND_UP(max_len, SMB2_MAX_BUFFER_SIZE);
324
325 if (credit_charge < calc_credit_num) {
326 ksmbd_debug(SMB, "Insufficient credit charge, given: %d, needed: %d\n",
327 credit_charge, calc_credit_num);
328 return 1;
329 } else if (credit_charge > conn->max_credits) {
330 ksmbd_debug(SMB, "Too large credit charge: %d\n", credit_charge);
331 return 1;
332 }
333
334 spin_lock(&conn->credits_lock);
335 if (credit_charge <= conn->total_credits) {
336 conn->total_credits -= credit_charge;
337 ret = 0;
338 } else {
339 ksmbd_debug(SMB, "Insufficient credits granted, given: %u, granted: %u\n",
340 credit_charge, conn->total_credits);
341 ret = 1;
342 }
343 spin_unlock(&conn->credits_lock);
344 return ret;
345 }
346
ksmbd_smb2_check_message(struct ksmbd_work * work)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
355 if (le32_to_cpu(hdr->NextCommand) > 0)
356 len = le32_to_cpu(hdr->NextCommand);
357 else if (work->next_smb2_rcv_hdr_off)
358 len -= work->next_smb2_rcv_hdr_off;
359
360 if (check_smb2_hdr(hdr))
361 return 1;
362
363 if (hdr->StructureSize != SMB2_HEADER_STRUCTURE_SIZE) {
364 ksmbd_debug(SMB, "Illegal structure size %u\n",
365 le16_to_cpu(hdr->StructureSize));
366 return 1;
367 }
368
369 command = le16_to_cpu(hdr->Command);
370 if (command >= NUMBER_OF_SMB2_COMMANDS) {
371 ksmbd_debug(SMB, "Illegal SMB2 command %d\n", command);
372 return 1;
373 }
374
375 if (smb2_req_struct_sizes[command] != pdu->StructureSize2) {
376 if (command != SMB2_OPLOCK_BREAK_HE &&
377 (hdr->Status == 0 || pdu->StructureSize2 != SMB2_ERROR_STRUCTURE_SIZE2_LE)) {
378 /* error packets have 9 byte structure size */
379 ksmbd_debug(SMB,
380 "Illegal request size %u for command %d\n",
381 le16_to_cpu(pdu->StructureSize2), command);
382 return 1;
383 } else if (command == SMB2_OPLOCK_BREAK_HE &&
384 hdr->Status == 0 &&
385 le16_to_cpu(pdu->StructureSize2) != OP_BREAK_STRUCT_SIZE_20 &&
386 le16_to_cpu(pdu->StructureSize2) != OP_BREAK_STRUCT_SIZE_21) {
387 /* special case for SMB2.1 lease break message */
388 ksmbd_debug(SMB,
389 "Illegal request size %d for oplock break\n",
390 le16_to_cpu(pdu->StructureSize2));
391 return 1;
392 }
393 }
394
395 if (smb2_calc_size(hdr, &clc_len))
396 return 1;
397
398 if (len != clc_len) {
399 /* client can return one byte more due to implied bcc[0] */
400 if (clc_len == len + 1)
401 goto validate_credit;
402
403 /*
404 * Some windows servers (win2016) will pad also the final
405 * PDU in a compound to 8 bytes.
406 */
407 if (ALIGN(clc_len, 8) == len)
408 goto validate_credit;
409
410 /*
411 * windows client also pad up to 8 bytes when compounding.
412 * If pad is longer than eight bytes, log the server behavior
413 * (once), since may indicate a problem but allow it and
414 * continue since the frame is parseable.
415 */
416 if (clc_len < len) {
417 ksmbd_debug(SMB,
418 "cli req padded more than expected. Length %d not %d for cmd:%d mid:%llu\n",
419 len, clc_len, command,
420 le64_to_cpu(hdr->MessageId));
421 goto validate_credit;
422 }
423
424 ksmbd_debug(SMB,
425 "cli req too short, len %d not %d. cmd:%d mid:%llu\n",
426 len, clc_len, command,
427 le64_to_cpu(hdr->MessageId));
428
429 return 1;
430 }
431
432 validate_credit:
433 if ((work->conn->vals->capabilities & SMB2_GLOBAL_CAP_LARGE_MTU) &&
434 smb2_validate_credit_charge(work->conn, hdr)) {
435 work->conn->ops->set_rsp_status(work, STATUS_INVALID_PARAMETER);
436 return 1;
437 }
438
439 return 0;
440 }
441
smb2_negotiate_request(struct ksmbd_work * work)442 int smb2_negotiate_request(struct ksmbd_work *work)
443 {
444 return ksmbd_smb_negotiate_common(work, SMB2_NEGOTIATE_HE);
445 }
446