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 /*
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 */
smb2_calc_size(void * buf,unsigned int * len)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
smb2_query_info_req_len(struct smb2_query_info_req * h)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
smb2_set_info_req_len(struct smb2_set_info_req * h)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
smb2_read_req_len(struct smb2_read_req * h)253 static inline int smb2_read_req_len(struct smb2_read_req *h)
254 {
255 return le32_to_cpu(h->Length);
256 }
257
smb2_write_req_len(struct smb2_write_req * h)258 static inline int smb2_write_req_len(struct smb2_write_req *h)
259 {
260 return le32_to_cpu(h->Length);
261 }
262
smb2_query_dir_req_len(struct smb2_query_directory_req * h)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
smb2_ioctl_req_len(struct smb2_ioctl_req * h)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
smb2_ioctl_resp_len(struct smb2_ioctl_req * h)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
smb2_validate_credit_charge(struct ksmbd_conn * conn,struct smb2_hdr * hdr)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
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 __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
smb2_negotiate_request(struct ksmbd_work * work)449 int smb2_negotiate_request(struct ksmbd_work *work)
450 {
451 return ksmbd_smb_negotiate_common(work, SMB2_NEGOTIATE_HE);
452 }
453
