xref: /openbmc/linux/fs/smb/client/misc.c (revision c0f767de)
1 // SPDX-License-Identifier: LGPL-2.1
2 /*
3  *
4  *   Copyright (C) International Business Machines  Corp., 2002,2008
5  *   Author(s): Steve French (sfrench@us.ibm.com)
6  *
7  */
8 
9 #include <linux/slab.h>
10 #include <linux/ctype.h>
11 #include <linux/mempool.h>
12 #include <linux/vmalloc.h>
13 #include "cifspdu.h"
14 #include "cifsglob.h"
15 #include "cifsproto.h"
16 #include "cifs_debug.h"
17 #include "smberr.h"
18 #include "nterr.h"
19 #include "cifs_unicode.h"
20 #include "smb2pdu.h"
21 #include "cifsfs.h"
22 #ifdef CONFIG_CIFS_DFS_UPCALL
23 #include "dns_resolve.h"
24 #include "dfs_cache.h"
25 #include "dfs.h"
26 #endif
27 #include "fs_context.h"
28 #include "cached_dir.h"
29 
30 /* The xid serves as a useful identifier for each incoming vfs request,
31    in a similar way to the mid which is useful to track each sent smb,
32    and CurrentXid can also provide a running counter (although it
33    will eventually wrap past zero) of the total vfs operations handled
34    since the cifs fs was mounted */
35 
36 unsigned int
_get_xid(void)37 _get_xid(void)
38 {
39 	unsigned int xid;
40 
41 	spin_lock(&GlobalMid_Lock);
42 	GlobalTotalActiveXid++;
43 
44 	/* keep high water mark for number of simultaneous ops in filesystem */
45 	if (GlobalTotalActiveXid > GlobalMaxActiveXid)
46 		GlobalMaxActiveXid = GlobalTotalActiveXid;
47 	if (GlobalTotalActiveXid > 65000)
48 		cifs_dbg(FYI, "warning: more than 65000 requests active\n");
49 	xid = GlobalCurrentXid++;
50 	spin_unlock(&GlobalMid_Lock);
51 	return xid;
52 }
53 
54 void
_free_xid(unsigned int xid)55 _free_xid(unsigned int xid)
56 {
57 	spin_lock(&GlobalMid_Lock);
58 	/* if (GlobalTotalActiveXid == 0)
59 		BUG(); */
60 	GlobalTotalActiveXid--;
61 	spin_unlock(&GlobalMid_Lock);
62 }
63 
64 struct cifs_ses *
sesInfoAlloc(void)65 sesInfoAlloc(void)
66 {
67 	struct cifs_ses *ret_buf;
68 
69 	ret_buf = kzalloc(sizeof(struct cifs_ses), GFP_KERNEL);
70 	if (ret_buf) {
71 		atomic_inc(&sesInfoAllocCount);
72 		spin_lock_init(&ret_buf->ses_lock);
73 		ret_buf->ses_status = SES_NEW;
74 		++ret_buf->ses_count;
75 		INIT_LIST_HEAD(&ret_buf->smb_ses_list);
76 		INIT_LIST_HEAD(&ret_buf->tcon_list);
77 		mutex_init(&ret_buf->session_mutex);
78 		spin_lock_init(&ret_buf->iface_lock);
79 		INIT_LIST_HEAD(&ret_buf->iface_list);
80 		spin_lock_init(&ret_buf->chan_lock);
81 	}
82 	return ret_buf;
83 }
84 
85 void
sesInfoFree(struct cifs_ses * buf_to_free)86 sesInfoFree(struct cifs_ses *buf_to_free)
87 {
88 	struct cifs_server_iface *iface = NULL, *niface = NULL;
89 
90 	if (buf_to_free == NULL) {
91 		cifs_dbg(FYI, "Null buffer passed to sesInfoFree\n");
92 		return;
93 	}
94 
95 	unload_nls(buf_to_free->local_nls);
96 	atomic_dec(&sesInfoAllocCount);
97 	kfree(buf_to_free->serverOS);
98 	kfree(buf_to_free->serverDomain);
99 	kfree(buf_to_free->serverNOS);
100 	kfree_sensitive(buf_to_free->password);
101 	kfree_sensitive(buf_to_free->password2);
102 	kfree(buf_to_free->user_name);
103 	kfree(buf_to_free->domainName);
104 	kfree_sensitive(buf_to_free->auth_key.response);
105 	spin_lock(&buf_to_free->iface_lock);
106 	list_for_each_entry_safe(iface, niface, &buf_to_free->iface_list,
107 				 iface_head)
108 		kref_put(&iface->refcount, release_iface);
109 	spin_unlock(&buf_to_free->iface_lock);
110 	kfree_sensitive(buf_to_free);
111 }
112 
113 struct cifs_tcon *
tcon_info_alloc(bool dir_leases_enabled,enum smb3_tcon_ref_trace trace)114 tcon_info_alloc(bool dir_leases_enabled, enum smb3_tcon_ref_trace trace)
115 {
116 	struct cifs_tcon *ret_buf;
117 	static atomic_t tcon_debug_id;
118 
119 	ret_buf = kzalloc(sizeof(*ret_buf), GFP_KERNEL);
120 	if (!ret_buf)
121 		return NULL;
122 
123 	if (dir_leases_enabled == true) {
124 		ret_buf->cfids = init_cached_dirs();
125 		if (!ret_buf->cfids) {
126 			kfree(ret_buf);
127 			return NULL;
128 		}
129 	}
130 	/* else ret_buf->cfids is already set to NULL above */
131 
132 	atomic_inc(&tconInfoAllocCount);
133 	ret_buf->status = TID_NEW;
134 	ret_buf->debug_id = atomic_inc_return(&tcon_debug_id);
135 	ret_buf->tc_count = 1;
136 	spin_lock_init(&ret_buf->tc_lock);
137 	INIT_LIST_HEAD(&ret_buf->openFileList);
138 	INIT_LIST_HEAD(&ret_buf->tcon_list);
139 	spin_lock_init(&ret_buf->open_file_lock);
140 	spin_lock_init(&ret_buf->stat_lock);
141 	atomic_set(&ret_buf->num_local_opens, 0);
142 	atomic_set(&ret_buf->num_remote_opens, 0);
143 	ret_buf->stats_from_time = ktime_get_real_seconds();
144 #ifdef CONFIG_CIFS_FSCACHE
145 	mutex_init(&ret_buf->fscache_lock);
146 #endif
147 	trace_smb3_tcon_ref(ret_buf->debug_id, ret_buf->tc_count, trace);
148 
149 	return ret_buf;
150 }
151 
152 void
tconInfoFree(struct cifs_tcon * tcon,enum smb3_tcon_ref_trace trace)153 tconInfoFree(struct cifs_tcon *tcon, enum smb3_tcon_ref_trace trace)
154 {
155 	if (tcon == NULL) {
156 		cifs_dbg(FYI, "Null buffer passed to tconInfoFree\n");
157 		return;
158 	}
159 	trace_smb3_tcon_ref(tcon->debug_id, tcon->tc_count, trace);
160 	free_cached_dirs(tcon->cfids);
161 	atomic_dec(&tconInfoAllocCount);
162 	kfree(tcon->nativeFileSystem);
163 	kfree_sensitive(tcon->password);
164 	kfree(tcon->origin_fullpath);
165 	kfree(tcon);
166 }
167 
168 struct smb_hdr *
cifs_buf_get(void)169 cifs_buf_get(void)
170 {
171 	struct smb_hdr *ret_buf = NULL;
172 	/*
173 	 * SMB2 header is bigger than CIFS one - no problems to clean some
174 	 * more bytes for CIFS.
175 	 */
176 	size_t buf_size = sizeof(struct smb2_hdr);
177 
178 	/*
179 	 * We could use negotiated size instead of max_msgsize -
180 	 * but it may be more efficient to always alloc same size
181 	 * albeit slightly larger than necessary and maxbuffersize
182 	 * defaults to this and can not be bigger.
183 	 */
184 	ret_buf = mempool_alloc(cifs_req_poolp, GFP_NOFS);
185 
186 	/* clear the first few header bytes */
187 	/* for most paths, more is cleared in header_assemble */
188 	memset(ret_buf, 0, buf_size + 3);
189 	atomic_inc(&buf_alloc_count);
190 #ifdef CONFIG_CIFS_STATS2
191 	atomic_inc(&total_buf_alloc_count);
192 #endif /* CONFIG_CIFS_STATS2 */
193 
194 	return ret_buf;
195 }
196 
197 void
cifs_buf_release(void * buf_to_free)198 cifs_buf_release(void *buf_to_free)
199 {
200 	if (buf_to_free == NULL) {
201 		/* cifs_dbg(FYI, "Null buffer passed to cifs_buf_release\n");*/
202 		return;
203 	}
204 	mempool_free(buf_to_free, cifs_req_poolp);
205 
206 	atomic_dec(&buf_alloc_count);
207 	return;
208 }
209 
210 struct smb_hdr *
cifs_small_buf_get(void)211 cifs_small_buf_get(void)
212 {
213 	struct smb_hdr *ret_buf = NULL;
214 
215 /* We could use negotiated size instead of max_msgsize -
216    but it may be more efficient to always alloc same size
217    albeit slightly larger than necessary and maxbuffersize
218    defaults to this and can not be bigger */
219 	ret_buf = mempool_alloc(cifs_sm_req_poolp, GFP_NOFS);
220 	/* No need to clear memory here, cleared in header assemble */
221 	/*	memset(ret_buf, 0, sizeof(struct smb_hdr) + 27);*/
222 	atomic_inc(&small_buf_alloc_count);
223 #ifdef CONFIG_CIFS_STATS2
224 	atomic_inc(&total_small_buf_alloc_count);
225 #endif /* CONFIG_CIFS_STATS2 */
226 
227 	return ret_buf;
228 }
229 
230 void
cifs_small_buf_release(void * buf_to_free)231 cifs_small_buf_release(void *buf_to_free)
232 {
233 
234 	if (buf_to_free == NULL) {
235 		cifs_dbg(FYI, "Null buffer passed to cifs_small_buf_release\n");
236 		return;
237 	}
238 	mempool_free(buf_to_free, cifs_sm_req_poolp);
239 
240 	atomic_dec(&small_buf_alloc_count);
241 	return;
242 }
243 
244 void
free_rsp_buf(int resp_buftype,void * rsp)245 free_rsp_buf(int resp_buftype, void *rsp)
246 {
247 	if (resp_buftype == CIFS_SMALL_BUFFER)
248 		cifs_small_buf_release(rsp);
249 	else if (resp_buftype == CIFS_LARGE_BUFFER)
250 		cifs_buf_release(rsp);
251 }
252 
253 /* NB: MID can not be set if treeCon not passed in, in that
254    case it is responsbility of caller to set the mid */
255 void
header_assemble(struct smb_hdr * buffer,char smb_command,const struct cifs_tcon * treeCon,int word_count)256 header_assemble(struct smb_hdr *buffer, char smb_command /* command */ ,
257 		const struct cifs_tcon *treeCon, int word_count
258 		/* length of fixed section (word count) in two byte units  */)
259 {
260 	char *temp = (char *) buffer;
261 
262 	memset(temp, 0, 256); /* bigger than MAX_CIFS_HDR_SIZE */
263 
264 	buffer->smb_buf_length = cpu_to_be32(
265 	    (2 * word_count) + sizeof(struct smb_hdr) -
266 	    4 /*  RFC 1001 length field does not count */  +
267 	    2 /* for bcc field itself */) ;
268 
269 	buffer->Protocol[0] = 0xFF;
270 	buffer->Protocol[1] = 'S';
271 	buffer->Protocol[2] = 'M';
272 	buffer->Protocol[3] = 'B';
273 	buffer->Command = smb_command;
274 	buffer->Flags = 0x00;	/* case sensitive */
275 	buffer->Flags2 = SMBFLG2_KNOWS_LONG_NAMES;
276 	buffer->Pid = cpu_to_le16((__u16)current->tgid);
277 	buffer->PidHigh = cpu_to_le16((__u16)(current->tgid >> 16));
278 	if (treeCon) {
279 		buffer->Tid = treeCon->tid;
280 		if (treeCon->ses) {
281 			if (treeCon->ses->capabilities & CAP_UNICODE)
282 				buffer->Flags2 |= SMBFLG2_UNICODE;
283 			if (treeCon->ses->capabilities & CAP_STATUS32)
284 				buffer->Flags2 |= SMBFLG2_ERR_STATUS;
285 
286 			/* Uid is not converted */
287 			buffer->Uid = treeCon->ses->Suid;
288 			if (treeCon->ses->server)
289 				buffer->Mid = get_next_mid(treeCon->ses->server);
290 		}
291 		if (treeCon->Flags & SMB_SHARE_IS_IN_DFS)
292 			buffer->Flags2 |= SMBFLG2_DFS;
293 		if (treeCon->nocase)
294 			buffer->Flags  |= SMBFLG_CASELESS;
295 		if ((treeCon->ses) && (treeCon->ses->server))
296 			if (treeCon->ses->server->sign)
297 				buffer->Flags2 |= SMBFLG2_SECURITY_SIGNATURE;
298 	}
299 
300 /*  endian conversion of flags is now done just before sending */
301 	buffer->WordCount = (char) word_count;
302 	return;
303 }
304 
305 static int
check_smb_hdr(struct smb_hdr * smb)306 check_smb_hdr(struct smb_hdr *smb)
307 {
308 	/* does it have the right SMB "signature" ? */
309 	if (*(__le32 *) smb->Protocol != cpu_to_le32(0x424d53ff)) {
310 		cifs_dbg(VFS, "Bad protocol string signature header 0x%x\n",
311 			 *(unsigned int *)smb->Protocol);
312 		return 1;
313 	}
314 
315 	/* if it's a response then accept */
316 	if (smb->Flags & SMBFLG_RESPONSE)
317 		return 0;
318 
319 	/* only one valid case where server sends us request */
320 	if (smb->Command == SMB_COM_LOCKING_ANDX)
321 		return 0;
322 
323 	cifs_dbg(VFS, "Server sent request, not response. mid=%u\n",
324 		 get_mid(smb));
325 	return 1;
326 }
327 
328 int
checkSMB(char * buf,unsigned int total_read,struct TCP_Server_Info * server)329 checkSMB(char *buf, unsigned int total_read, struct TCP_Server_Info *server)
330 {
331 	struct smb_hdr *smb = (struct smb_hdr *)buf;
332 	__u32 rfclen = be32_to_cpu(smb->smb_buf_length);
333 	__u32 clc_len;  /* calculated length */
334 	cifs_dbg(FYI, "checkSMB Length: 0x%x, smb_buf_length: 0x%x\n",
335 		 total_read, rfclen);
336 
337 	/* is this frame too small to even get to a BCC? */
338 	if (total_read < 2 + sizeof(struct smb_hdr)) {
339 		if ((total_read >= sizeof(struct smb_hdr) - 1)
340 			    && (smb->Status.CifsError != 0)) {
341 			/* it's an error return */
342 			smb->WordCount = 0;
343 			/* some error cases do not return wct and bcc */
344 			return 0;
345 		} else if ((total_read == sizeof(struct smb_hdr) + 1) &&
346 				(smb->WordCount == 0)) {
347 			char *tmp = (char *)smb;
348 			/* Need to work around a bug in two servers here */
349 			/* First, check if the part of bcc they sent was zero */
350 			if (tmp[sizeof(struct smb_hdr)] == 0) {
351 				/* some servers return only half of bcc
352 				 * on simple responses (wct, bcc both zero)
353 				 * in particular have seen this on
354 				 * ulogoffX and FindClose. This leaves
355 				 * one byte of bcc potentially unitialized
356 				 */
357 				/* zero rest of bcc */
358 				tmp[sizeof(struct smb_hdr)+1] = 0;
359 				return 0;
360 			}
361 			cifs_dbg(VFS, "rcvd invalid byte count (bcc)\n");
362 		} else {
363 			cifs_dbg(VFS, "Length less than smb header size\n");
364 		}
365 		return -EIO;
366 	} else if (total_read < sizeof(*smb) + 2 * smb->WordCount) {
367 		cifs_dbg(VFS, "%s: can't read BCC due to invalid WordCount(%u)\n",
368 			 __func__, smb->WordCount);
369 		return -EIO;
370 	}
371 
372 	/* otherwise, there is enough to get to the BCC */
373 	if (check_smb_hdr(smb))
374 		return -EIO;
375 	clc_len = smbCalcSize(smb);
376 
377 	if (4 + rfclen != total_read) {
378 		cifs_dbg(VFS, "Length read does not match RFC1001 length %d\n",
379 			 rfclen);
380 		return -EIO;
381 	}
382 
383 	if (4 + rfclen != clc_len) {
384 		__u16 mid = get_mid(smb);
385 		/* check if bcc wrapped around for large read responses */
386 		if ((rfclen > 64 * 1024) && (rfclen > clc_len)) {
387 			/* check if lengths match mod 64K */
388 			if (((4 + rfclen) & 0xFFFF) == (clc_len & 0xFFFF))
389 				return 0; /* bcc wrapped */
390 		}
391 		cifs_dbg(FYI, "Calculated size %u vs length %u mismatch for mid=%u\n",
392 			 clc_len, 4 + rfclen, mid);
393 
394 		if (4 + rfclen < clc_len) {
395 			cifs_dbg(VFS, "RFC1001 size %u smaller than SMB for mid=%u\n",
396 				 rfclen, mid);
397 			return -EIO;
398 		} else if (rfclen > clc_len + 512) {
399 			/*
400 			 * Some servers (Windows XP in particular) send more
401 			 * data than the lengths in the SMB packet would
402 			 * indicate on certain calls (byte range locks and
403 			 * trans2 find first calls in particular). While the
404 			 * client can handle such a frame by ignoring the
405 			 * trailing data, we choose limit the amount of extra
406 			 * data to 512 bytes.
407 			 */
408 			cifs_dbg(VFS, "RFC1001 size %u more than 512 bytes larger than SMB for mid=%u\n",
409 				 rfclen, mid);
410 			return -EIO;
411 		}
412 	}
413 	return 0;
414 }
415 
416 bool
is_valid_oplock_break(char * buffer,struct TCP_Server_Info * srv)417 is_valid_oplock_break(char *buffer, struct TCP_Server_Info *srv)
418 {
419 	struct smb_hdr *buf = (struct smb_hdr *)buffer;
420 	struct smb_com_lock_req *pSMB = (struct smb_com_lock_req *)buf;
421 	struct TCP_Server_Info *pserver;
422 	struct cifs_ses *ses;
423 	struct cifs_tcon *tcon;
424 	struct cifsInodeInfo *pCifsInode;
425 	struct cifsFileInfo *netfile;
426 
427 	cifs_dbg(FYI, "Checking for oplock break or dnotify response\n");
428 	if ((pSMB->hdr.Command == SMB_COM_NT_TRANSACT) &&
429 	   (pSMB->hdr.Flags & SMBFLG_RESPONSE)) {
430 		struct smb_com_transaction_change_notify_rsp *pSMBr =
431 			(struct smb_com_transaction_change_notify_rsp *)buf;
432 		struct file_notify_information *pnotify;
433 		__u32 data_offset = 0;
434 		size_t len = srv->total_read - sizeof(pSMBr->hdr.smb_buf_length);
435 
436 		if (get_bcc(buf) > sizeof(struct file_notify_information)) {
437 			data_offset = le32_to_cpu(pSMBr->DataOffset);
438 
439 			if (data_offset >
440 			    len - sizeof(struct file_notify_information)) {
441 				cifs_dbg(FYI, "Invalid data_offset %u\n",
442 					 data_offset);
443 				return true;
444 			}
445 			pnotify = (struct file_notify_information *)
446 				((char *)&pSMBr->hdr.Protocol + data_offset);
447 			cifs_dbg(FYI, "dnotify on %s Action: 0x%x\n",
448 				 pnotify->FileName, pnotify->Action);
449 			/*   cifs_dump_mem("Rcvd notify Data: ",buf,
450 				sizeof(struct smb_hdr)+60); */
451 			return true;
452 		}
453 		if (pSMBr->hdr.Status.CifsError) {
454 			cifs_dbg(FYI, "notify err 0x%x\n",
455 				 pSMBr->hdr.Status.CifsError);
456 			return true;
457 		}
458 		return false;
459 	}
460 	if (pSMB->hdr.Command != SMB_COM_LOCKING_ANDX)
461 		return false;
462 	if (pSMB->hdr.Flags & SMBFLG_RESPONSE) {
463 		/* no sense logging error on invalid handle on oplock
464 		   break - harmless race between close request and oplock
465 		   break response is expected from time to time writing out
466 		   large dirty files cached on the client */
467 		if ((NT_STATUS_INVALID_HANDLE) ==
468 		   le32_to_cpu(pSMB->hdr.Status.CifsError)) {
469 			cifs_dbg(FYI, "Invalid handle on oplock break\n");
470 			return true;
471 		} else if (ERRbadfid ==
472 		   le16_to_cpu(pSMB->hdr.Status.DosError.Error)) {
473 			return true;
474 		} else {
475 			return false; /* on valid oplock brk we get "request" */
476 		}
477 	}
478 	if (pSMB->hdr.WordCount != 8)
479 		return false;
480 
481 	cifs_dbg(FYI, "oplock type 0x%x level 0x%x\n",
482 		 pSMB->LockType, pSMB->OplockLevel);
483 	if (!(pSMB->LockType & LOCKING_ANDX_OPLOCK_RELEASE))
484 		return false;
485 
486 	/* If server is a channel, select the primary channel */
487 	pserver = SERVER_IS_CHAN(srv) ? srv->primary_server : srv;
488 
489 	/* look up tcon based on tid & uid */
490 	spin_lock(&cifs_tcp_ses_lock);
491 	list_for_each_entry(ses, &pserver->smb_ses_list, smb_ses_list) {
492 		if (cifs_ses_exiting(ses))
493 			continue;
494 		list_for_each_entry(tcon, &ses->tcon_list, tcon_list) {
495 			if (tcon->tid != buf->Tid)
496 				continue;
497 
498 			cifs_stats_inc(&tcon->stats.cifs_stats.num_oplock_brks);
499 			spin_lock(&tcon->open_file_lock);
500 			list_for_each_entry(netfile, &tcon->openFileList, tlist) {
501 				if (pSMB->Fid != netfile->fid.netfid)
502 					continue;
503 
504 				cifs_dbg(FYI, "file id match, oplock break\n");
505 				pCifsInode = CIFS_I(d_inode(netfile->dentry));
506 
507 				set_bit(CIFS_INODE_PENDING_OPLOCK_BREAK,
508 					&pCifsInode->flags);
509 
510 				netfile->oplock_epoch = 0;
511 				netfile->oplock_level = pSMB->OplockLevel;
512 				netfile->oplock_break_cancelled = false;
513 				cifs_queue_oplock_break(netfile);
514 
515 				spin_unlock(&tcon->open_file_lock);
516 				spin_unlock(&cifs_tcp_ses_lock);
517 				return true;
518 			}
519 			spin_unlock(&tcon->open_file_lock);
520 			spin_unlock(&cifs_tcp_ses_lock);
521 			cifs_dbg(FYI, "No matching file for oplock break\n");
522 			return true;
523 		}
524 	}
525 	spin_unlock(&cifs_tcp_ses_lock);
526 	cifs_dbg(FYI, "Can not process oplock break for non-existent connection\n");
527 	return true;
528 }
529 
530 void
dump_smb(void * buf,int smb_buf_length)531 dump_smb(void *buf, int smb_buf_length)
532 {
533 	if (traceSMB == 0)
534 		return;
535 
536 	print_hex_dump(KERN_DEBUG, "", DUMP_PREFIX_NONE, 8, 2, buf,
537 		       smb_buf_length, true);
538 }
539 
540 void
cifs_autodisable_serverino(struct cifs_sb_info * cifs_sb)541 cifs_autodisable_serverino(struct cifs_sb_info *cifs_sb)
542 {
543 	if (cifs_sb->mnt_cifs_flags & CIFS_MOUNT_SERVER_INUM) {
544 		struct cifs_tcon *tcon = NULL;
545 
546 		if (cifs_sb->master_tlink)
547 			tcon = cifs_sb_master_tcon(cifs_sb);
548 
549 		cifs_sb->mnt_cifs_flags &= ~CIFS_MOUNT_SERVER_INUM;
550 		cifs_sb->mnt_cifs_serverino_autodisabled = true;
551 		cifs_dbg(VFS, "Autodisabling the use of server inode numbers on %s\n",
552 			 tcon ? tcon->tree_name : "new server");
553 		cifs_dbg(VFS, "The server doesn't seem to support them properly or the files might be on different servers (DFS)\n");
554 		cifs_dbg(VFS, "Hardlinks will not be recognized on this mount. Consider mounting with the \"noserverino\" option to silence this message.\n");
555 
556 	}
557 }
558 
cifs_set_oplock_level(struct cifsInodeInfo * cinode,__u32 oplock)559 void cifs_set_oplock_level(struct cifsInodeInfo *cinode, __u32 oplock)
560 {
561 	oplock &= 0xF;
562 
563 	if (oplock == OPLOCK_EXCLUSIVE) {
564 		cinode->oplock = CIFS_CACHE_WRITE_FLG | CIFS_CACHE_READ_FLG;
565 		cifs_dbg(FYI, "Exclusive Oplock granted on inode %p\n",
566 			 &cinode->netfs.inode);
567 	} else if (oplock == OPLOCK_READ) {
568 		cinode->oplock = CIFS_CACHE_READ_FLG;
569 		cifs_dbg(FYI, "Level II Oplock granted on inode %p\n",
570 			 &cinode->netfs.inode);
571 	} else
572 		cinode->oplock = 0;
573 }
574 
575 /*
576  * We wait for oplock breaks to be processed before we attempt to perform
577  * writes.
578  */
cifs_get_writer(struct cifsInodeInfo * cinode)579 int cifs_get_writer(struct cifsInodeInfo *cinode)
580 {
581 	int rc;
582 
583 start:
584 	rc = wait_on_bit(&cinode->flags, CIFS_INODE_PENDING_OPLOCK_BREAK,
585 			 TASK_KILLABLE);
586 	if (rc)
587 		return rc;
588 
589 	spin_lock(&cinode->writers_lock);
590 	if (!cinode->writers)
591 		set_bit(CIFS_INODE_PENDING_WRITERS, &cinode->flags);
592 	cinode->writers++;
593 	/* Check to see if we have started servicing an oplock break */
594 	if (test_bit(CIFS_INODE_PENDING_OPLOCK_BREAK, &cinode->flags)) {
595 		cinode->writers--;
596 		if (cinode->writers == 0) {
597 			clear_bit(CIFS_INODE_PENDING_WRITERS, &cinode->flags);
598 			wake_up_bit(&cinode->flags, CIFS_INODE_PENDING_WRITERS);
599 		}
600 		spin_unlock(&cinode->writers_lock);
601 		goto start;
602 	}
603 	spin_unlock(&cinode->writers_lock);
604 	return 0;
605 }
606 
cifs_put_writer(struct cifsInodeInfo * cinode)607 void cifs_put_writer(struct cifsInodeInfo *cinode)
608 {
609 	spin_lock(&cinode->writers_lock);
610 	cinode->writers--;
611 	if (cinode->writers == 0) {
612 		clear_bit(CIFS_INODE_PENDING_WRITERS, &cinode->flags);
613 		wake_up_bit(&cinode->flags, CIFS_INODE_PENDING_WRITERS);
614 	}
615 	spin_unlock(&cinode->writers_lock);
616 }
617 
618 /**
619  * cifs_queue_oplock_break - queue the oplock break handler for cfile
620  * @cfile: The file to break the oplock on
621  *
622  * This function is called from the demultiplex thread when it
623  * receives an oplock break for @cfile.
624  *
625  * Assumes the tcon->open_file_lock is held.
626  * Assumes cfile->file_info_lock is NOT held.
627  */
cifs_queue_oplock_break(struct cifsFileInfo * cfile)628 void cifs_queue_oplock_break(struct cifsFileInfo *cfile)
629 {
630 	/*
631 	 * Bump the handle refcount now while we hold the
632 	 * open_file_lock to enforce the validity of it for the oplock
633 	 * break handler. The matching put is done at the end of the
634 	 * handler.
635 	 */
636 	cifsFileInfo_get(cfile);
637 
638 	queue_work(cifsoplockd_wq, &cfile->oplock_break);
639 }
640 
cifs_done_oplock_break(struct cifsInodeInfo * cinode)641 void cifs_done_oplock_break(struct cifsInodeInfo *cinode)
642 {
643 	clear_bit(CIFS_INODE_PENDING_OPLOCK_BREAK, &cinode->flags);
644 	wake_up_bit(&cinode->flags, CIFS_INODE_PENDING_OPLOCK_BREAK);
645 }
646 
647 bool
backup_cred(struct cifs_sb_info * cifs_sb)648 backup_cred(struct cifs_sb_info *cifs_sb)
649 {
650 	if (cifs_sb->mnt_cifs_flags & CIFS_MOUNT_CIFS_BACKUPUID) {
651 		if (uid_eq(cifs_sb->ctx->backupuid, current_fsuid()))
652 			return true;
653 	}
654 	if (cifs_sb->mnt_cifs_flags & CIFS_MOUNT_CIFS_BACKUPGID) {
655 		if (in_group_p(cifs_sb->ctx->backupgid))
656 			return true;
657 	}
658 
659 	return false;
660 }
661 
662 void
cifs_del_pending_open(struct cifs_pending_open * open)663 cifs_del_pending_open(struct cifs_pending_open *open)
664 {
665 	spin_lock(&tlink_tcon(open->tlink)->open_file_lock);
666 	list_del(&open->olist);
667 	spin_unlock(&tlink_tcon(open->tlink)->open_file_lock);
668 }
669 
670 void
cifs_add_pending_open_locked(struct cifs_fid * fid,struct tcon_link * tlink,struct cifs_pending_open * open)671 cifs_add_pending_open_locked(struct cifs_fid *fid, struct tcon_link *tlink,
672 			     struct cifs_pending_open *open)
673 {
674 	memcpy(open->lease_key, fid->lease_key, SMB2_LEASE_KEY_SIZE);
675 	open->oplock = CIFS_OPLOCK_NO_CHANGE;
676 	open->tlink = tlink;
677 	fid->pending_open = open;
678 	list_add_tail(&open->olist, &tlink_tcon(tlink)->pending_opens);
679 }
680 
681 void
cifs_add_pending_open(struct cifs_fid * fid,struct tcon_link * tlink,struct cifs_pending_open * open)682 cifs_add_pending_open(struct cifs_fid *fid, struct tcon_link *tlink,
683 		      struct cifs_pending_open *open)
684 {
685 	spin_lock(&tlink_tcon(tlink)->open_file_lock);
686 	cifs_add_pending_open_locked(fid, tlink, open);
687 	spin_unlock(&tlink_tcon(open->tlink)->open_file_lock);
688 }
689 
690 /*
691  * Critical section which runs after acquiring deferred_lock.
692  * As there is no reference count on cifs_deferred_close, pdclose
693  * should not be used outside deferred_lock.
694  */
695 bool
cifs_is_deferred_close(struct cifsFileInfo * cfile,struct cifs_deferred_close ** pdclose)696 cifs_is_deferred_close(struct cifsFileInfo *cfile, struct cifs_deferred_close **pdclose)
697 {
698 	struct cifs_deferred_close *dclose;
699 
700 	list_for_each_entry(dclose, &CIFS_I(d_inode(cfile->dentry))->deferred_closes, dlist) {
701 		if ((dclose->netfid == cfile->fid.netfid) &&
702 			(dclose->persistent_fid == cfile->fid.persistent_fid) &&
703 			(dclose->volatile_fid == cfile->fid.volatile_fid)) {
704 			*pdclose = dclose;
705 			return true;
706 		}
707 	}
708 	return false;
709 }
710 
711 /*
712  * Critical section which runs after acquiring deferred_lock.
713  */
714 void
cifs_add_deferred_close(struct cifsFileInfo * cfile,struct cifs_deferred_close * dclose)715 cifs_add_deferred_close(struct cifsFileInfo *cfile, struct cifs_deferred_close *dclose)
716 {
717 	bool is_deferred = false;
718 	struct cifs_deferred_close *pdclose;
719 
720 	is_deferred = cifs_is_deferred_close(cfile, &pdclose);
721 	if (is_deferred) {
722 		kfree(dclose);
723 		return;
724 	}
725 
726 	dclose->tlink = cfile->tlink;
727 	dclose->netfid = cfile->fid.netfid;
728 	dclose->persistent_fid = cfile->fid.persistent_fid;
729 	dclose->volatile_fid = cfile->fid.volatile_fid;
730 	list_add_tail(&dclose->dlist, &CIFS_I(d_inode(cfile->dentry))->deferred_closes);
731 }
732 
733 /*
734  * Critical section which runs after acquiring deferred_lock.
735  */
736 void
cifs_del_deferred_close(struct cifsFileInfo * cfile)737 cifs_del_deferred_close(struct cifsFileInfo *cfile)
738 {
739 	bool is_deferred = false;
740 	struct cifs_deferred_close *dclose;
741 
742 	is_deferred = cifs_is_deferred_close(cfile, &dclose);
743 	if (!is_deferred)
744 		return;
745 	list_del(&dclose->dlist);
746 	kfree(dclose);
747 }
748 
749 void
cifs_close_deferred_file(struct cifsInodeInfo * cifs_inode)750 cifs_close_deferred_file(struct cifsInodeInfo *cifs_inode)
751 {
752 	struct cifsFileInfo *cfile = NULL;
753 	struct file_list *tmp_list, *tmp_next_list;
754 	struct list_head file_head;
755 
756 	if (cifs_inode == NULL)
757 		return;
758 
759 	INIT_LIST_HEAD(&file_head);
760 	spin_lock(&cifs_inode->open_file_lock);
761 	list_for_each_entry(cfile, &cifs_inode->openFileList, flist) {
762 		if (delayed_work_pending(&cfile->deferred)) {
763 			if (cancel_delayed_work(&cfile->deferred)) {
764 				spin_lock(&cifs_inode->deferred_lock);
765 				cifs_del_deferred_close(cfile);
766 				spin_unlock(&cifs_inode->deferred_lock);
767 
768 				tmp_list = kmalloc(sizeof(struct file_list), GFP_ATOMIC);
769 				if (tmp_list == NULL)
770 					break;
771 				tmp_list->cfile = cfile;
772 				list_add_tail(&tmp_list->list, &file_head);
773 			}
774 		}
775 	}
776 	spin_unlock(&cifs_inode->open_file_lock);
777 
778 	list_for_each_entry_safe(tmp_list, tmp_next_list, &file_head, list) {
779 		_cifsFileInfo_put(tmp_list->cfile, false, false);
780 		list_del(&tmp_list->list);
781 		kfree(tmp_list);
782 	}
783 }
784 
785 void
cifs_close_all_deferred_files(struct cifs_tcon * tcon)786 cifs_close_all_deferred_files(struct cifs_tcon *tcon)
787 {
788 	struct cifsFileInfo *cfile;
789 	struct file_list *tmp_list, *tmp_next_list;
790 	struct list_head file_head;
791 
792 	INIT_LIST_HEAD(&file_head);
793 	spin_lock(&tcon->open_file_lock);
794 	list_for_each_entry(cfile, &tcon->openFileList, tlist) {
795 		if (delayed_work_pending(&cfile->deferred)) {
796 			if (cancel_delayed_work(&cfile->deferred)) {
797 				spin_lock(&CIFS_I(d_inode(cfile->dentry))->deferred_lock);
798 				cifs_del_deferred_close(cfile);
799 				spin_unlock(&CIFS_I(d_inode(cfile->dentry))->deferred_lock);
800 
801 				tmp_list = kmalloc(sizeof(struct file_list), GFP_ATOMIC);
802 				if (tmp_list == NULL)
803 					break;
804 				tmp_list->cfile = cfile;
805 				list_add_tail(&tmp_list->list, &file_head);
806 			}
807 		}
808 	}
809 	spin_unlock(&tcon->open_file_lock);
810 
811 	list_for_each_entry_safe(tmp_list, tmp_next_list, &file_head, list) {
812 		_cifsFileInfo_put(tmp_list->cfile, true, false);
813 		list_del(&tmp_list->list);
814 		kfree(tmp_list);
815 	}
816 }
817 void
cifs_close_deferred_file_under_dentry(struct cifs_tcon * tcon,const char * path)818 cifs_close_deferred_file_under_dentry(struct cifs_tcon *tcon, const char *path)
819 {
820 	struct cifsFileInfo *cfile;
821 	struct file_list *tmp_list, *tmp_next_list;
822 	struct list_head file_head;
823 	void *page;
824 	const char *full_path;
825 
826 	INIT_LIST_HEAD(&file_head);
827 	page = alloc_dentry_path();
828 	spin_lock(&tcon->open_file_lock);
829 	list_for_each_entry(cfile, &tcon->openFileList, tlist) {
830 		full_path = build_path_from_dentry(cfile->dentry, page);
831 		if (strstr(full_path, path)) {
832 			if (delayed_work_pending(&cfile->deferred)) {
833 				if (cancel_delayed_work(&cfile->deferred)) {
834 					spin_lock(&CIFS_I(d_inode(cfile->dentry))->deferred_lock);
835 					cifs_del_deferred_close(cfile);
836 					spin_unlock(&CIFS_I(d_inode(cfile->dentry))->deferred_lock);
837 
838 					tmp_list = kmalloc(sizeof(struct file_list), GFP_ATOMIC);
839 					if (tmp_list == NULL)
840 						break;
841 					tmp_list->cfile = cfile;
842 					list_add_tail(&tmp_list->list, &file_head);
843 				}
844 			}
845 		}
846 	}
847 	spin_unlock(&tcon->open_file_lock);
848 
849 	list_for_each_entry_safe(tmp_list, tmp_next_list, &file_head, list) {
850 		_cifsFileInfo_put(tmp_list->cfile, true, false);
851 		list_del(&tmp_list->list);
852 		kfree(tmp_list);
853 	}
854 	free_dentry_path(page);
855 }
856 
857 /*
858  * If a dentry has been deleted, all corresponding open handles should know that
859  * so that we do not defer close them.
860  */
cifs_mark_open_handles_for_deleted_file(struct inode * inode,const char * path)861 void cifs_mark_open_handles_for_deleted_file(struct inode *inode,
862 					     const char *path)
863 {
864 	struct cifsFileInfo *cfile;
865 	void *page;
866 	const char *full_path;
867 	struct cifsInodeInfo *cinode = CIFS_I(inode);
868 
869 	page = alloc_dentry_path();
870 	spin_lock(&cinode->open_file_lock);
871 
872 	/*
873 	 * note: we need to construct path from dentry and compare only if the
874 	 * inode has any hardlinks. When number of hardlinks is 1, we can just
875 	 * mark all open handles since they are going to be from the same file.
876 	 */
877 	if (inode->i_nlink > 1) {
878 		list_for_each_entry(cfile, &cinode->openFileList, flist) {
879 			full_path = build_path_from_dentry(cfile->dentry, page);
880 			if (!IS_ERR(full_path) && strcmp(full_path, path) == 0)
881 				cfile->status_file_deleted = true;
882 		}
883 	} else {
884 		list_for_each_entry(cfile, &cinode->openFileList, flist)
885 			cfile->status_file_deleted = true;
886 	}
887 	spin_unlock(&cinode->open_file_lock);
888 	free_dentry_path(page);
889 }
890 
891 /* parses DFS referral V3 structure
892  * caller is responsible for freeing target_nodes
893  * returns:
894  * - on success - 0
895  * - on failure - errno
896  */
897 int
parse_dfs_referrals(struct get_dfs_referral_rsp * rsp,u32 rsp_size,unsigned int * num_of_nodes,struct dfs_info3_param ** target_nodes,const struct nls_table * nls_codepage,int remap,const char * searchName,bool is_unicode)898 parse_dfs_referrals(struct get_dfs_referral_rsp *rsp, u32 rsp_size,
899 		    unsigned int *num_of_nodes,
900 		    struct dfs_info3_param **target_nodes,
901 		    const struct nls_table *nls_codepage, int remap,
902 		    const char *searchName, bool is_unicode)
903 {
904 	int i, rc = 0;
905 	char *data_end;
906 	struct dfs_referral_level_3 *ref;
907 
908 	*num_of_nodes = le16_to_cpu(rsp->NumberOfReferrals);
909 
910 	if (*num_of_nodes < 1) {
911 		cifs_dbg(VFS, "num_referrals: must be at least > 0, but we get num_referrals = %d\n",
912 			 *num_of_nodes);
913 		rc = -EINVAL;
914 		goto parse_DFS_referrals_exit;
915 	}
916 
917 	ref = (struct dfs_referral_level_3 *) &(rsp->referrals);
918 	if (ref->VersionNumber != cpu_to_le16(3)) {
919 		cifs_dbg(VFS, "Referrals of V%d version are not supported, should be V3\n",
920 			 le16_to_cpu(ref->VersionNumber));
921 		rc = -EINVAL;
922 		goto parse_DFS_referrals_exit;
923 	}
924 
925 	/* get the upper boundary of the resp buffer */
926 	data_end = (char *)rsp + rsp_size;
927 
928 	cifs_dbg(FYI, "num_referrals: %d dfs flags: 0x%x ...\n",
929 		 *num_of_nodes, le32_to_cpu(rsp->DFSFlags));
930 
931 	*target_nodes = kcalloc(*num_of_nodes, sizeof(struct dfs_info3_param),
932 				GFP_KERNEL);
933 	if (*target_nodes == NULL) {
934 		rc = -ENOMEM;
935 		goto parse_DFS_referrals_exit;
936 	}
937 
938 	/* collect necessary data from referrals */
939 	for (i = 0; i < *num_of_nodes; i++) {
940 		char *temp;
941 		int max_len;
942 		struct dfs_info3_param *node = (*target_nodes)+i;
943 
944 		node->flags = le32_to_cpu(rsp->DFSFlags);
945 		if (is_unicode) {
946 			__le16 *tmp = kmalloc(strlen(searchName)*2 + 2,
947 						GFP_KERNEL);
948 			if (tmp == NULL) {
949 				rc = -ENOMEM;
950 				goto parse_DFS_referrals_exit;
951 			}
952 			cifsConvertToUTF16((__le16 *) tmp, searchName,
953 					   PATH_MAX, nls_codepage, remap);
954 			node->path_consumed = cifs_utf16_bytes(tmp,
955 					le16_to_cpu(rsp->PathConsumed),
956 					nls_codepage);
957 			kfree(tmp);
958 		} else
959 			node->path_consumed = le16_to_cpu(rsp->PathConsumed);
960 
961 		node->server_type = le16_to_cpu(ref->ServerType);
962 		node->ref_flag = le16_to_cpu(ref->ReferralEntryFlags);
963 
964 		/* copy DfsPath */
965 		temp = (char *)ref + le16_to_cpu(ref->DfsPathOffset);
966 		max_len = data_end - temp;
967 		node->path_name = cifs_strndup_from_utf16(temp, max_len,
968 						is_unicode, nls_codepage);
969 		if (!node->path_name) {
970 			rc = -ENOMEM;
971 			goto parse_DFS_referrals_exit;
972 		}
973 
974 		/* copy link target UNC */
975 		temp = (char *)ref + le16_to_cpu(ref->NetworkAddressOffset);
976 		max_len = data_end - temp;
977 		node->node_name = cifs_strndup_from_utf16(temp, max_len,
978 						is_unicode, nls_codepage);
979 		if (!node->node_name) {
980 			rc = -ENOMEM;
981 			goto parse_DFS_referrals_exit;
982 		}
983 
984 		node->ttl = le32_to_cpu(ref->TimeToLive);
985 
986 		ref++;
987 	}
988 
989 parse_DFS_referrals_exit:
990 	if (rc) {
991 		free_dfs_info_array(*target_nodes, *num_of_nodes);
992 		*target_nodes = NULL;
993 		*num_of_nodes = 0;
994 	}
995 	return rc;
996 }
997 
998 struct cifs_aio_ctx *
cifs_aio_ctx_alloc(void)999 cifs_aio_ctx_alloc(void)
1000 {
1001 	struct cifs_aio_ctx *ctx;
1002 
1003 	/*
1004 	 * Must use kzalloc to initialize ctx->bv to NULL and ctx->direct_io
1005 	 * to false so that we know when we have to unreference pages within
1006 	 * cifs_aio_ctx_release()
1007 	 */
1008 	ctx = kzalloc(sizeof(struct cifs_aio_ctx), GFP_KERNEL);
1009 	if (!ctx)
1010 		return NULL;
1011 
1012 	INIT_LIST_HEAD(&ctx->list);
1013 	mutex_init(&ctx->aio_mutex);
1014 	init_completion(&ctx->done);
1015 	kref_init(&ctx->refcount);
1016 	return ctx;
1017 }
1018 
1019 void
cifs_aio_ctx_release(struct kref * refcount)1020 cifs_aio_ctx_release(struct kref *refcount)
1021 {
1022 	struct cifs_aio_ctx *ctx = container_of(refcount,
1023 					struct cifs_aio_ctx, refcount);
1024 
1025 	cifsFileInfo_put(ctx->cfile);
1026 
1027 	/*
1028 	 * ctx->bv is only set if setup_aio_ctx_iter() was call successfuly
1029 	 * which means that iov_iter_extract_pages() was a success and thus
1030 	 * that we may have references or pins on pages that we need to
1031 	 * release.
1032 	 */
1033 	if (ctx->bv) {
1034 		if (ctx->should_dirty || ctx->bv_need_unpin) {
1035 			unsigned int i;
1036 
1037 			for (i = 0; i < ctx->nr_pinned_pages; i++) {
1038 				struct page *page = ctx->bv[i].bv_page;
1039 
1040 				if (ctx->should_dirty)
1041 					set_page_dirty(page);
1042 				if (ctx->bv_need_unpin)
1043 					unpin_user_page(page);
1044 			}
1045 		}
1046 		kvfree(ctx->bv);
1047 	}
1048 
1049 	kfree(ctx);
1050 }
1051 
1052 /**
1053  * cifs_alloc_hash - allocate hash and hash context together
1054  * @name: The name of the crypto hash algo
1055  * @sdesc: SHASH descriptor where to put the pointer to the hash TFM
1056  *
1057  * The caller has to make sure @sdesc is initialized to either NULL or
1058  * a valid context. It can be freed via cifs_free_hash().
1059  */
1060 int
cifs_alloc_hash(const char * name,struct shash_desc ** sdesc)1061 cifs_alloc_hash(const char *name, struct shash_desc **sdesc)
1062 {
1063 	int rc = 0;
1064 	struct crypto_shash *alg = NULL;
1065 
1066 	if (*sdesc)
1067 		return 0;
1068 
1069 	alg = crypto_alloc_shash(name, 0, 0);
1070 	if (IS_ERR(alg)) {
1071 		cifs_dbg(VFS, "Could not allocate shash TFM '%s'\n", name);
1072 		rc = PTR_ERR(alg);
1073 		*sdesc = NULL;
1074 		return rc;
1075 	}
1076 
1077 	*sdesc = kmalloc(sizeof(struct shash_desc) + crypto_shash_descsize(alg), GFP_KERNEL);
1078 	if (*sdesc == NULL) {
1079 		cifs_dbg(VFS, "no memory left to allocate shash TFM '%s'\n", name);
1080 		crypto_free_shash(alg);
1081 		return -ENOMEM;
1082 	}
1083 
1084 	(*sdesc)->tfm = alg;
1085 	return 0;
1086 }
1087 
1088 /**
1089  * cifs_free_hash - free hash and hash context together
1090  * @sdesc: Where to find the pointer to the hash TFM
1091  *
1092  * Freeing a NULL descriptor is safe.
1093  */
1094 void
cifs_free_hash(struct shash_desc ** sdesc)1095 cifs_free_hash(struct shash_desc **sdesc)
1096 {
1097 	if (unlikely(!sdesc) || !*sdesc)
1098 		return;
1099 
1100 	if ((*sdesc)->tfm) {
1101 		crypto_free_shash((*sdesc)->tfm);
1102 		(*sdesc)->tfm = NULL;
1103 	}
1104 
1105 	kfree_sensitive(*sdesc);
1106 	*sdesc = NULL;
1107 }
1108 
extract_unc_hostname(const char * unc,const char ** h,size_t * len)1109 void extract_unc_hostname(const char *unc, const char **h, size_t *len)
1110 {
1111 	const char *end;
1112 
1113 	/* skip initial slashes */
1114 	while (*unc && (*unc == '\\' || *unc == '/'))
1115 		unc++;
1116 
1117 	end = unc;
1118 
1119 	while (*end && !(*end == '\\' || *end == '/'))
1120 		end++;
1121 
1122 	*h = unc;
1123 	*len = end - unc;
1124 }
1125 
1126 /**
1127  * copy_path_name - copy src path to dst, possibly truncating
1128  * @dst: The destination buffer
1129  * @src: The source name
1130  *
1131  * returns number of bytes written (including trailing nul)
1132  */
copy_path_name(char * dst,const char * src)1133 int copy_path_name(char *dst, const char *src)
1134 {
1135 	int name_len;
1136 
1137 	/*
1138 	 * PATH_MAX includes nul, so if strlen(src) >= PATH_MAX it
1139 	 * will truncate and strlen(dst) will be PATH_MAX-1
1140 	 */
1141 	name_len = strscpy(dst, src, PATH_MAX);
1142 	if (WARN_ON_ONCE(name_len < 0))
1143 		name_len = PATH_MAX-1;
1144 
1145 	/* we count the trailing nul */
1146 	name_len++;
1147 	return name_len;
1148 }
1149 
1150 struct super_cb_data {
1151 	void *data;
1152 	struct super_block *sb;
1153 };
1154 
tcon_super_cb(struct super_block * sb,void * arg)1155 static void tcon_super_cb(struct super_block *sb, void *arg)
1156 {
1157 	struct super_cb_data *sd = arg;
1158 	struct cifs_sb_info *cifs_sb;
1159 	struct cifs_tcon *t1 = sd->data, *t2;
1160 
1161 	if (sd->sb)
1162 		return;
1163 
1164 	cifs_sb = CIFS_SB(sb);
1165 	t2 = cifs_sb_master_tcon(cifs_sb);
1166 
1167 	spin_lock(&t2->tc_lock);
1168 	if (t1->ses == t2->ses &&
1169 	    t1->ses->server == t2->ses->server &&
1170 	    t2->origin_fullpath &&
1171 	    dfs_src_pathname_equal(t2->origin_fullpath, t1->origin_fullpath))
1172 		sd->sb = sb;
1173 	spin_unlock(&t2->tc_lock);
1174 }
1175 
__cifs_get_super(void (* f)(struct super_block *,void *),void * data)1176 static struct super_block *__cifs_get_super(void (*f)(struct super_block *, void *),
1177 					    void *data)
1178 {
1179 	struct super_cb_data sd = {
1180 		.data = data,
1181 		.sb = NULL,
1182 	};
1183 	struct file_system_type **fs_type = (struct file_system_type *[]) {
1184 		&cifs_fs_type, &smb3_fs_type, NULL,
1185 	};
1186 
1187 	for (; *fs_type; fs_type++) {
1188 		iterate_supers_type(*fs_type, f, &sd);
1189 		if (sd.sb) {
1190 			/*
1191 			 * Grab an active reference in order to prevent automounts (DFS links)
1192 			 * of expiring and then freeing up our cifs superblock pointer while
1193 			 * we're doing failover.
1194 			 */
1195 			cifs_sb_active(sd.sb);
1196 			return sd.sb;
1197 		}
1198 	}
1199 	pr_warn_once("%s: could not find dfs superblock\n", __func__);
1200 	return ERR_PTR(-EINVAL);
1201 }
1202 
__cifs_put_super(struct super_block * sb)1203 static void __cifs_put_super(struct super_block *sb)
1204 {
1205 	if (!IS_ERR_OR_NULL(sb))
1206 		cifs_sb_deactive(sb);
1207 }
1208 
cifs_get_dfs_tcon_super(struct cifs_tcon * tcon)1209 struct super_block *cifs_get_dfs_tcon_super(struct cifs_tcon *tcon)
1210 {
1211 	spin_lock(&tcon->tc_lock);
1212 	if (!tcon->origin_fullpath) {
1213 		spin_unlock(&tcon->tc_lock);
1214 		return ERR_PTR(-ENOENT);
1215 	}
1216 	spin_unlock(&tcon->tc_lock);
1217 	return __cifs_get_super(tcon_super_cb, tcon);
1218 }
1219 
cifs_put_tcp_super(struct super_block * sb)1220 void cifs_put_tcp_super(struct super_block *sb)
1221 {
1222 	__cifs_put_super(sb);
1223 }
1224 
1225 #ifdef CONFIG_CIFS_DFS_UPCALL
match_target_ip(struct TCP_Server_Info * server,const char * share,size_t share_len,bool * result)1226 int match_target_ip(struct TCP_Server_Info *server,
1227 		    const char *share, size_t share_len,
1228 		    bool *result)
1229 {
1230 	int rc;
1231 	char *target;
1232 	struct sockaddr_storage ss;
1233 
1234 	*result = false;
1235 
1236 	target = kzalloc(share_len + 3, GFP_KERNEL);
1237 	if (!target)
1238 		return -ENOMEM;
1239 
1240 	scnprintf(target, share_len + 3, "\\\\%.*s", (int)share_len, share);
1241 
1242 	cifs_dbg(FYI, "%s: target name: %s\n", __func__, target + 2);
1243 
1244 	rc = dns_resolve_server_name_to_ip(target, (struct sockaddr *)&ss, NULL);
1245 	kfree(target);
1246 
1247 	if (rc < 0)
1248 		return rc;
1249 
1250 	spin_lock(&server->srv_lock);
1251 	*result = cifs_match_ipaddr((struct sockaddr *)&server->dstaddr, (struct sockaddr *)&ss);
1252 	spin_unlock(&server->srv_lock);
1253 	cifs_dbg(FYI, "%s: ip addresses match: %u\n", __func__, *result);
1254 	return 0;
1255 }
1256 
cifs_update_super_prepath(struct cifs_sb_info * cifs_sb,char * prefix)1257 int cifs_update_super_prepath(struct cifs_sb_info *cifs_sb, char *prefix)
1258 {
1259 	int rc;
1260 
1261 	kfree(cifs_sb->prepath);
1262 	cifs_sb->prepath = NULL;
1263 
1264 	if (prefix && *prefix) {
1265 		cifs_sb->prepath = cifs_sanitize_prepath(prefix, GFP_ATOMIC);
1266 		if (IS_ERR(cifs_sb->prepath)) {
1267 			rc = PTR_ERR(cifs_sb->prepath);
1268 			cifs_sb->prepath = NULL;
1269 			return rc;
1270 		}
1271 		if (cifs_sb->prepath)
1272 			convert_delimiter(cifs_sb->prepath, CIFS_DIR_SEP(cifs_sb));
1273 	}
1274 
1275 	cifs_sb->mnt_cifs_flags |= CIFS_MOUNT_USE_PREFIX_PATH;
1276 	return 0;
1277 }
1278 
1279 /*
1280  * Handle weird Windows SMB server behaviour. It responds with
1281  * STATUS_OBJECT_NAME_INVALID code to SMB2 QUERY_INFO request for
1282  * "\<server>\<dfsname>\<linkpath>" DFS reference, where <dfsname> contains
1283  * non-ASCII unicode symbols.
1284  */
cifs_inval_name_dfs_link_error(const unsigned int xid,struct cifs_tcon * tcon,struct cifs_sb_info * cifs_sb,const char * full_path,bool * islink)1285 int cifs_inval_name_dfs_link_error(const unsigned int xid,
1286 				   struct cifs_tcon *tcon,
1287 				   struct cifs_sb_info *cifs_sb,
1288 				   const char *full_path,
1289 				   bool *islink)
1290 {
1291 	struct TCP_Server_Info *server = tcon->ses->server;
1292 	struct cifs_ses *ses = tcon->ses;
1293 	size_t len;
1294 	char *path;
1295 	char *ref_path;
1296 
1297 	*islink = false;
1298 
1299 	/*
1300 	 * Fast path - skip check when @full_path doesn't have a prefix path to
1301 	 * look up or tcon is not DFS.
1302 	 */
1303 	if (strlen(full_path) < 2 || !cifs_sb ||
1304 	    (cifs_sb->mnt_cifs_flags & CIFS_MOUNT_NO_DFS) ||
1305 	    !is_tcon_dfs(tcon))
1306 		return 0;
1307 
1308 	spin_lock(&server->srv_lock);
1309 	if (!server->leaf_fullpath) {
1310 		spin_unlock(&server->srv_lock);
1311 		return 0;
1312 	}
1313 	spin_unlock(&server->srv_lock);
1314 
1315 	/*
1316 	 * Slow path - tcon is DFS and @full_path has prefix path, so attempt
1317 	 * to get a referral to figure out whether it is an DFS link.
1318 	 */
1319 	len = strnlen(tcon->tree_name, MAX_TREE_SIZE + 1) + strlen(full_path) + 1;
1320 	path = kmalloc(len, GFP_KERNEL);
1321 	if (!path)
1322 		return -ENOMEM;
1323 
1324 	scnprintf(path, len, "%s%s", tcon->tree_name, full_path);
1325 	ref_path = dfs_cache_canonical_path(path + 1, cifs_sb->local_nls,
1326 					    cifs_remap(cifs_sb));
1327 	kfree(path);
1328 
1329 	if (IS_ERR(ref_path)) {
1330 		if (PTR_ERR(ref_path) != -EINVAL)
1331 			return PTR_ERR(ref_path);
1332 	} else {
1333 		struct dfs_info3_param *refs = NULL;
1334 		int num_refs = 0;
1335 
1336 		/*
1337 		 * XXX: we are not using dfs_cache_find() here because we might
1338 		 * end up filling all the DFS cache and thus potentially
1339 		 * removing cached DFS targets that the client would eventually
1340 		 * need during failover.
1341 		 */
1342 		ses = CIFS_DFS_ROOT_SES(ses);
1343 		if (ses->server->ops->get_dfs_refer &&
1344 		    !ses->server->ops->get_dfs_refer(xid, ses, ref_path, &refs,
1345 						     &num_refs, cifs_sb->local_nls,
1346 						     cifs_remap(cifs_sb)))
1347 			*islink = refs[0].server_type == DFS_TYPE_LINK;
1348 		free_dfs_info_array(refs, num_refs);
1349 		kfree(ref_path);
1350 	}
1351 	return 0;
1352 }
1353 #endif
1354 
cifs_wait_for_server_reconnect(struct TCP_Server_Info * server,bool retry)1355 int cifs_wait_for_server_reconnect(struct TCP_Server_Info *server, bool retry)
1356 {
1357 	int timeout = 10;
1358 	int rc;
1359 
1360 	spin_lock(&server->srv_lock);
1361 	if (server->tcpStatus != CifsNeedReconnect) {
1362 		spin_unlock(&server->srv_lock);
1363 		return 0;
1364 	}
1365 	timeout *= server->nr_targets;
1366 	spin_unlock(&server->srv_lock);
1367 
1368 	/*
1369 	 * Give demultiplex thread up to 10 seconds to each target available for
1370 	 * reconnect -- should be greater than cifs socket timeout which is 7
1371 	 * seconds.
1372 	 *
1373 	 * On "soft" mounts we wait once. Hard mounts keep retrying until
1374 	 * process is killed or server comes back on-line.
1375 	 */
1376 	do {
1377 		rc = wait_event_interruptible_timeout(server->response_q,
1378 						      (server->tcpStatus != CifsNeedReconnect),
1379 						      timeout * HZ);
1380 		if (rc < 0) {
1381 			cifs_dbg(FYI, "%s: aborting reconnect due to received signal\n",
1382 				 __func__);
1383 			return -ERESTARTSYS;
1384 		}
1385 
1386 		/* are we still trying to reconnect? */
1387 		spin_lock(&server->srv_lock);
1388 		if (server->tcpStatus != CifsNeedReconnect) {
1389 			spin_unlock(&server->srv_lock);
1390 			return 0;
1391 		}
1392 		spin_unlock(&server->srv_lock);
1393 	} while (retry);
1394 
1395 	cifs_dbg(FYI, "%s: gave up waiting on reconnect\n", __func__);
1396 	return -EHOSTDOWN;
1397 }
1398