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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 unsigned short int name_off =
110 le16_to_cpu(((struct smb2_create_req *)hdr)->NameOffset);
111 unsigned short int name_len =
112 le16_to_cpu(((struct smb2_create_req *)hdr)->NameLength);
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 if (!name_len)
120 break;
121
122 if (name_off + name_len < (u64)*off + *len)
123 break;
124 }
125
126 *off = name_off;
127 *len = name_len;
128 break;
129 }
130 case SMB2_QUERY_INFO:
131 *off = le16_to_cpu(((struct smb2_query_info_req *)hdr)->InputBufferOffset);
132 *len = le32_to_cpu(((struct smb2_query_info_req *)hdr)->InputBufferLength);
133 break;
134 case SMB2_SET_INFO:
135 *off = le16_to_cpu(((struct smb2_set_info_req *)hdr)->BufferOffset);
136 *len = le32_to_cpu(((struct smb2_set_info_req *)hdr)->BufferLength);
137 break;
138 case SMB2_READ:
139 *off = le16_to_cpu(((struct smb2_read_req *)hdr)->ReadChannelInfoOffset);
140 *len = le16_to_cpu(((struct smb2_read_req *)hdr)->ReadChannelInfoLength);
141 break;
142 case SMB2_WRITE:
143 if (((struct smb2_write_req *)hdr)->DataOffset ||
144 ((struct smb2_write_req *)hdr)->Length) {
145 *off = max_t(unsigned int,
146 le16_to_cpu(((struct smb2_write_req *)hdr)->DataOffset),
147 offsetof(struct smb2_write_req, Buffer));
148 *len = le32_to_cpu(((struct smb2_write_req *)hdr)->Length);
149 break;
150 }
151
152 *off = le16_to_cpu(((struct smb2_write_req *)hdr)->WriteChannelInfoOffset);
153 *len = le16_to_cpu(((struct smb2_write_req *)hdr)->WriteChannelInfoLength);
154 break;
155 case SMB2_QUERY_DIRECTORY:
156 *off = le16_to_cpu(((struct smb2_query_directory_req *)hdr)->FileNameOffset);
157 *len = le16_to_cpu(((struct smb2_query_directory_req *)hdr)->FileNameLength);
158 break;
159 case SMB2_LOCK:
160 {
161 unsigned short lock_count;
162
163 lock_count = le16_to_cpu(((struct smb2_lock_req *)hdr)->LockCount);
164 if (lock_count > 0) {
165 *off = offsetof(struct smb2_lock_req, locks);
166 *len = sizeof(struct smb2_lock_element) * lock_count;
167 }
168 break;
169 }
170 case SMB2_IOCTL:
171 *off = le32_to_cpu(((struct smb2_ioctl_req *)hdr)->InputOffset);
172 *len = le32_to_cpu(((struct smb2_ioctl_req *)hdr)->InputCount);
173 break;
174 default:
175 ksmbd_debug(SMB, "no length check for command\n");
176 break;
177 }
178
179 if (*off > 4096) {
180 ksmbd_debug(SMB, "offset %d too large\n", *off);
181 ret = -EINVAL;
182 } else if ((u64)*off + *len > MAX_STREAM_PROT_LEN) {
183 ksmbd_debug(SMB, "Request is larger than maximum stream protocol length(%u): %llu\n",
184 MAX_STREAM_PROT_LEN, (u64)*off + *len);
185 ret = -EINVAL;
186 }
187
188 return ret;
189}
190
191/*
192 * Calculate the size of the SMB message based on the fixed header
193 * portion, the number of word parameters and the data portion of the message.
194 */
195static int smb2_calc_size(void *buf, unsigned int *len)
196{
197 struct smb2_pdu *pdu = (struct smb2_pdu *)buf;
198 struct smb2_hdr *hdr = &pdu->hdr;
199 unsigned int offset; /* the offset from the beginning of SMB to data area */
200 unsigned int data_length; /* the length of the variable length data area */
201 int ret;
202
203 /* Structure Size has already been checked to make sure it is 64 */
204 *len = le16_to_cpu(hdr->StructureSize);
205
206 /*
207 * StructureSize2, ie length of fixed parameter area has already
208 * been checked to make sure it is the correct length.
209 */
210 *len += le16_to_cpu(pdu->StructureSize2);
211 /*
212 * StructureSize2 of smb2_lock pdu is set to 48, indicating
213 * the size of smb2 lock request with single smb2_lock_element
214 * regardless of number of locks. Subtract single
215 * smb2_lock_element for correct buffer size check.
216 */
217 if (hdr->Command == SMB2_LOCK)
218 *len -= sizeof(struct smb2_lock_element);
219
220 if (has_smb2_data_area[le16_to_cpu(hdr->Command)] == false)
221 goto calc_size_exit;
222
223 ret = smb2_get_data_area_len(&offset, &data_length, hdr);
224 if (ret)
225 return ret;
226 ksmbd_debug(SMB, "SMB2 data length %u offset %u\n", data_length,
227 offset);
228
229 if (data_length > 0) {
230 /*
231 * Check to make sure that data area begins after fixed area,
232 * Note that last byte of the fixed area is part of data area
233 * for some commands, typically those with odd StructureSize,
234 * so we must add one to the calculation.
235 */
236 if (offset + 1 < *len) {
237 ksmbd_debug(SMB,
238 "data area offset %d overlaps SMB2 header %u\n",
239 offset + 1, *len);
240 return -EINVAL;
241 }
242
243 *len = offset + data_length;
244 }
245
246calc_size_exit:
247 ksmbd_debug(SMB, "SMB2 len %u\n", *len);
248 return 0;
249}
250
251static inline int smb2_query_info_req_len(struct smb2_query_info_req *h)
252{
253 return le32_to_cpu(h->InputBufferLength) +
254 le32_to_cpu(h->OutputBufferLength);
255}
256
257static inline int smb2_set_info_req_len(struct smb2_set_info_req *h)
258{
259 return le32_to_cpu(h->BufferLength);
260}
261
262static inline int smb2_read_req_len(struct smb2_read_req *h)
263{
264 return le32_to_cpu(h->Length);
265}
266
267static inline int smb2_write_req_len(struct smb2_write_req *h)
268{
269 return le32_to_cpu(h->Length);
270}
271
272static inline int smb2_query_dir_req_len(struct smb2_query_directory_req *h)
273{
274 return le32_to_cpu(h->OutputBufferLength);
275}
276
277static inline int smb2_ioctl_req_len(struct smb2_ioctl_req *h)
278{
279 return le32_to_cpu(h->InputCount) +
280 le32_to_cpu(h->OutputCount);
281}
282
283static inline int smb2_ioctl_resp_len(struct smb2_ioctl_req *h)
284{
285 return le32_to_cpu(h->MaxInputResponse) +
286 le32_to_cpu(h->MaxOutputResponse);
287}
288
289static int smb2_validate_credit_charge(struct ksmbd_conn *conn,
290 struct smb2_hdr *hdr)
291{
292 unsigned int req_len = 0, expect_resp_len = 0, calc_credit_num, max_len;
293 unsigned short credit_charge = le16_to_cpu(hdr->CreditCharge);
294 void *__hdr = hdr;
295 int ret = 0;
296
297 switch (hdr->Command) {
298 case SMB2_QUERY_INFO:
299 req_len = smb2_query_info_req_len(__hdr);
300 break;
301 case SMB2_SET_INFO:
302 req_len = smb2_set_info_req_len(__hdr);
303 break;
304 case SMB2_READ:
305 req_len = smb2_read_req_len(__hdr);
306 break;
307 case SMB2_WRITE:
308 req_len = smb2_write_req_len(__hdr);
309 break;
310 case SMB2_QUERY_DIRECTORY:
311 req_len = smb2_query_dir_req_len(__hdr);
312 break;
313 case SMB2_IOCTL:
314 req_len = smb2_ioctl_req_len(__hdr);
315 expect_resp_len = smb2_ioctl_resp_len(__hdr);
316 break;
317 case SMB2_CANCEL:
318 return 0;
319 default:
320 req_len = 1;
321 break;
322 }
323
324 credit_charge = max_t(unsigned short, credit_charge, 1);
325 max_len = max_t(unsigned int, req_len, expect_resp_len);
326 calc_credit_num = DIV_ROUND_UP(max_len, SMB2_MAX_BUFFER_SIZE);
327
328 if (credit_charge < calc_credit_num) {
329 ksmbd_debug(SMB, "Insufficient credit charge, given: %d, needed: %d\n",
330 credit_charge, calc_credit_num);
331 return 1;
332 } else if (credit_charge > conn->vals->max_credits) {
333 ksmbd_debug(SMB, "Too large credit charge: %d\n", credit_charge);
334 return 1;
335 }
336
337 spin_lock(&conn->credits_lock);
338 if (credit_charge > conn->total_credits) {
339 ksmbd_debug(SMB, "Insufficient credits granted, given: %u, granted: %u\n",
340 credit_charge, conn->total_credits);
341 ret = 1;
342 }
343
344 if ((u64)conn->outstanding_credits + credit_charge > conn->total_credits) {
345 ksmbd_debug(SMB, "Limits exceeding the maximum allowable outstanding requests, given : %u, pending : %u\n",
346 credit_charge, conn->outstanding_credits);
347 ret = 1;
348 } else
349 conn->outstanding_credits += credit_charge;
350
351 spin_unlock(&conn->credits_lock);
352
353 return ret;
354}
355
356int ksmbd_smb2_check_message(struct ksmbd_work *work)
357{
358 struct smb2_pdu *pdu = ksmbd_req_buf_next(work);
359 struct smb2_hdr *hdr = &pdu->hdr;
360 int command;
361 __u32 clc_len; /* calculated length */
362 __u32 len = get_rfc1002_len(work->request_buf);
363 __u32 req_struct_size, next_cmd = le32_to_cpu(hdr->NextCommand);
364
365 if ((u64)work->next_smb2_rcv_hdr_off + next_cmd > len) {
366 pr_err("next command(%u) offset exceeds smb msg size\n",
367 next_cmd);
368 return 1;
369 }
370
371 if (next_cmd > 0)
372 len = next_cmd;
373 else if (work->next_smb2_rcv_hdr_off)
374 len -= work->next_smb2_rcv_hdr_off;
375
376 if (check_smb2_hdr(hdr))
377 return 1;
378
379 if (hdr->StructureSize != SMB2_HEADER_STRUCTURE_SIZE) {
380 ksmbd_debug(SMB, "Illegal structure size %u\n",
381 le16_to_cpu(hdr->StructureSize));
382 return 1;
383 }
384
385 command = le16_to_cpu(hdr->Command);
386 if (command >= NUMBER_OF_SMB2_COMMANDS) {
387 ksmbd_debug(SMB, "Illegal SMB2 command %d\n", command);
388 return 1;
389 }
390
391 if (smb2_req_struct_sizes[command] != pdu->StructureSize2) {
392 if (!(command == SMB2_OPLOCK_BREAK_HE &&
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 %u for command %d\n",
398 le16_to_cpu(pdu->StructureSize2), command);
399 return 1;
400 }
401 }
402
403 req_struct_size = le16_to_cpu(pdu->StructureSize2) +
404 __SMB2_HEADER_STRUCTURE_SIZE;
405 if (command == SMB2_LOCK_HE)
406 req_struct_size -= sizeof(struct smb2_lock_element);
407
408 if (req_struct_size > len + 1)
409 return 1;
410
411 if (smb2_calc_size(hdr, &clc_len))
412 return 1;
413
414 if (len != clc_len) {
415 /* client can return one byte more due to implied bcc[0] */
416 if (clc_len == len + 1)
417 goto validate_credit;
418
419 /*
420 * Some windows servers (win2016) will pad also the final
421 * PDU in a compound to 8 bytes.
422 */
423 if (ALIGN(clc_len, 8) == len)
424 goto validate_credit;
425
426 /*
427 * SMB2 NEGOTIATE request will be validated when message
428 * handling proceeds.
429 */
430 if (command == SMB2_NEGOTIATE_HE)
431 goto validate_credit;
432
433 /*
434 * Allow a message that padded to 8byte boundary.
435 * Linux 4.19.217 with smb 3.0.2 are sometimes
436 * sending messages where the cls_len is exactly
437 * 8 bytes less than len.
438 */
439 if (clc_len < len && (len - clc_len) <= 8)
440 goto validate_credit;
441
442 pr_err_ratelimited(
443 "cli req too short, len %d not %d. cmd:%d mid:%llu\n",
444 len, clc_len, command,
445 le64_to_cpu(hdr->MessageId));
446
447 return 1;
448 }
449
450validate_credit:
451 if ((work->conn->vals->capabilities & SMB2_GLOBAL_CAP_LARGE_MTU) &&
452 smb2_validate_credit_charge(work->conn, hdr))
453 return 1;
454
455 return 0;
456}
457
458int smb2_negotiate_request(struct ksmbd_work *work)
459{
460 return ksmbd_smb_negotiate_common(work, SMB2_NEGOTIATE_HE);
461}