GNU Linux-libre 6.1.86-gnu
[releases.git] / fs / smb / server / smb2misc.c
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
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  */
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                 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  */
195 static 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
246 calc_size_exit:
247         ksmbd_debug(SMB, "SMB2 len %u\n", *len);
248         return 0;
249 }
250
251 static 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
257 static inline int smb2_set_info_req_len(struct smb2_set_info_req *h)
258 {
259         return le32_to_cpu(h->BufferLength);
260 }
261
262 static inline int smb2_read_req_len(struct smb2_read_req *h)
263 {
264         return le32_to_cpu(h->Length);
265 }
266
267 static inline int smb2_write_req_len(struct smb2_write_req *h)
268 {
269         return le32_to_cpu(h->Length);
270 }
271
272 static inline int smb2_query_dir_req_len(struct smb2_query_directory_req *h)
273 {
274         return le32_to_cpu(h->OutputBufferLength);
275 }
276
277 static 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
283 static 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
289 static 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
356 int 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
450 validate_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
458 int smb2_negotiate_request(struct ksmbd_work *work)
459 {
460         return ksmbd_smb_negotiate_common(work, SMB2_NEGOTIATE_HE);
461 }