1// SPDX-License-Identifier: LGPL-2.1
2/*
3 *
4 *   Copyright (C) International Business Machines  Corp., 2002, 2011
5 *   Author(s): Steve French (sfrench@us.ibm.com),
6 *              Pavel Shilovsky ((pshilovsky@samba.org) 2012
7 *
8 */
9#include <linux/fs.h>
10#include <linux/filelock.h>
11#include <linux/stat.h>
12#include <linux/slab.h>
13#include <linux/pagemap.h>
14#include <asm/div64.h>
15#include "cifsfs.h"
16#include "cifspdu.h"
17#include "cifsglob.h"
18#include "cifsproto.h"
19#include "cifs_debug.h"
20#include "cifs_fs_sb.h"
21#include "cifs_unicode.h"
22#include "fscache.h"
23#include "smb2proto.h"
24#include "smb2status.h"
25
26static struct smb2_symlink_err_rsp *symlink_data(const struct kvec *iov)
27{
28	struct smb2_err_rsp *err = iov->iov_base;
29	struct smb2_symlink_err_rsp *sym = ERR_PTR(-EINVAL);
30	u32 len;
31
32	if (err->ErrorContextCount) {
33		struct smb2_error_context_rsp *p, *end;
34
35		len = (u32)err->ErrorContextCount * (offsetof(struct smb2_error_context_rsp,
36							      ErrorContextData) +
37						     sizeof(struct smb2_symlink_err_rsp));
38		if (le32_to_cpu(err->ByteCount) < len || iov->iov_len < len + sizeof(*err) + 1)
39			return ERR_PTR(-EINVAL);
40
41		p = (struct smb2_error_context_rsp *)err->ErrorData;
42		end = (struct smb2_error_context_rsp *)((u8 *)err + iov->iov_len);
43		do {
44			if (le32_to_cpu(p->ErrorId) == SMB2_ERROR_ID_DEFAULT) {
45				sym = (struct smb2_symlink_err_rsp *)&p->ErrorContextData;
46				break;
47			}
48			cifs_dbg(FYI, "%s: skipping unhandled error context: 0x%x\n",
49				 __func__, le32_to_cpu(p->ErrorId));
50
51			len = ALIGN(le32_to_cpu(p->ErrorDataLength), 8);
52			p = (struct smb2_error_context_rsp *)((u8 *)&p->ErrorContextData + len);
53		} while (p < end);
54	} else if (le32_to_cpu(err->ByteCount) >= sizeof(*sym) &&
55		   iov->iov_len >= SMB2_SYMLINK_STRUCT_SIZE) {
56		sym = (struct smb2_symlink_err_rsp *)err->ErrorData;
57	}
58
59	if (!IS_ERR(sym) && (le32_to_cpu(sym->SymLinkErrorTag) != SYMLINK_ERROR_TAG ||
60			     le32_to_cpu(sym->ReparseTag) != IO_REPARSE_TAG_SYMLINK))
61		sym = ERR_PTR(-EINVAL);
62
63	return sym;
64}
65
66int smb2_parse_symlink_response(struct cifs_sb_info *cifs_sb, const struct kvec *iov, char **path)
67{
68	struct smb2_symlink_err_rsp *sym;
69	unsigned int sub_offs, sub_len;
70	unsigned int print_offs, print_len;
71	char *s;
72
73	if (!cifs_sb || !iov || !iov->iov_base || !iov->iov_len || !path)
74		return -EINVAL;
75
76	sym = symlink_data(iov);
77	if (IS_ERR(sym))
78		return PTR_ERR(sym);
79
80	sub_len = le16_to_cpu(sym->SubstituteNameLength);
81	sub_offs = le16_to_cpu(sym->SubstituteNameOffset);
82	print_len = le16_to_cpu(sym->PrintNameLength);
83	print_offs = le16_to_cpu(sym->PrintNameOffset);
84
85	if (iov->iov_len < SMB2_SYMLINK_STRUCT_SIZE + sub_offs + sub_len ||
86	    iov->iov_len < SMB2_SYMLINK_STRUCT_SIZE + print_offs + print_len)
87		return -EINVAL;
88
89	s = cifs_strndup_from_utf16((char *)sym->PathBuffer + sub_offs, sub_len, true,
90				    cifs_sb->local_nls);
91	if (!s)
92		return -ENOMEM;
93	convert_delimiter(s, '/');
94	cifs_dbg(FYI, "%s: symlink target: %s\n", __func__, s);
95
96	*path = s;
97	return 0;
98}
99
100int smb2_open_file(const unsigned int xid, struct cifs_open_parms *oparms, __u32 *oplock, void *buf)
101{
102	int rc;
103	__le16 *smb2_path;
104	__u8 smb2_oplock;
105	struct cifs_open_info_data *data = buf;
106	struct smb2_file_all_info file_info = {};
107	struct smb2_file_all_info *smb2_data = data ? &file_info : NULL;
108	struct kvec err_iov = {};
109	int err_buftype = CIFS_NO_BUFFER;
110	struct cifs_fid *fid = oparms->fid;
111	struct network_resiliency_req nr_ioctl_req;
112
113	smb2_path = cifs_convert_path_to_utf16(oparms->path, oparms->cifs_sb);
114	if (smb2_path == NULL)
115		return -ENOMEM;
116
117	oparms->desired_access |= FILE_READ_ATTRIBUTES;
118	smb2_oplock = SMB2_OPLOCK_LEVEL_BATCH;
119
120	rc = SMB2_open(xid, oparms, smb2_path, &smb2_oplock, smb2_data, NULL, &err_iov,
121		       &err_buftype);
122	if (rc && data) {
123		struct smb2_hdr *hdr = err_iov.iov_base;
124
125		if (unlikely(!err_iov.iov_base || err_buftype == CIFS_NO_BUFFER))
126			goto out;
127		if (hdr->Status == STATUS_STOPPED_ON_SYMLINK) {
128			rc = smb2_parse_symlink_response(oparms->cifs_sb, &err_iov,
129							 &data->symlink_target);
130			if (!rc) {
131				memset(smb2_data, 0, sizeof(*smb2_data));
132				oparms->create_options |= OPEN_REPARSE_POINT;
133				rc = SMB2_open(xid, oparms, smb2_path, &smb2_oplock, smb2_data,
134					       NULL, NULL, NULL);
135				oparms->create_options &= ~OPEN_REPARSE_POINT;
136			}
137		}
138	}
139
140	if (rc)
141		goto out;
142
143	if (oparms->tcon->use_resilient) {
144		/* default timeout is 0, servers pick default (120 seconds) */
145		nr_ioctl_req.Timeout =
146			cpu_to_le32(oparms->tcon->handle_timeout);
147		nr_ioctl_req.Reserved = 0;
148		rc = SMB2_ioctl(xid, oparms->tcon, fid->persistent_fid,
149			fid->volatile_fid, FSCTL_LMR_REQUEST_RESILIENCY,
150			(char *)&nr_ioctl_req, sizeof(nr_ioctl_req),
151			CIFSMaxBufSize, NULL, NULL /* no return info */);
152		if (rc == -EOPNOTSUPP) {
153			cifs_dbg(VFS,
154			     "resiliency not supported by server, disabling\n");
155			oparms->tcon->use_resilient = false;
156		} else if (rc)
157			cifs_dbg(FYI, "error %d setting resiliency\n", rc);
158
159		rc = 0;
160	}
161
162	if (smb2_data) {
163		/* if open response does not have IndexNumber field - get it */
164		if (smb2_data->IndexNumber == 0) {
165			rc = SMB2_get_srv_num(xid, oparms->tcon,
166				      fid->persistent_fid,
167				      fid->volatile_fid,
168				      &smb2_data->IndexNumber);
169			if (rc) {
170				/*
171				 * let get_inode_info disable server inode
172				 * numbers
173				 */
174				smb2_data->IndexNumber = 0;
175				rc = 0;
176			}
177		}
178		memcpy(&data->fi, smb2_data, sizeof(data->fi));
179	}
180
181	*oplock = smb2_oplock;
182out:
183	free_rsp_buf(err_buftype, err_iov.iov_base);
184	kfree(smb2_path);
185	return rc;
186}
187
188int
189smb2_unlock_range(struct cifsFileInfo *cfile, struct file_lock *flock,
190		  const unsigned int xid)
191{
192	int rc = 0, stored_rc;
193	unsigned int max_num, num = 0, max_buf;
194	struct smb2_lock_element *buf, *cur;
195	struct cifs_tcon *tcon = tlink_tcon(cfile->tlink);
196	struct cifsInodeInfo *cinode = CIFS_I(d_inode(cfile->dentry));
197	struct cifsLockInfo *li, *tmp;
198	__u64 length = 1 + flock->fl_end - flock->fl_start;
199	struct list_head tmp_llist;
200
201	INIT_LIST_HEAD(&tmp_llist);
202
203	/*
204	 * Accessing maxBuf is racy with cifs_reconnect - need to store value
205	 * and check it before using.
206	 */
207	max_buf = tcon->ses->server->maxBuf;
208	if (max_buf < sizeof(struct smb2_lock_element))
209		return -EINVAL;
210
211	BUILD_BUG_ON(sizeof(struct smb2_lock_element) > PAGE_SIZE);
212	max_buf = min_t(unsigned int, max_buf, PAGE_SIZE);
213	max_num = max_buf / sizeof(struct smb2_lock_element);
214	buf = kcalloc(max_num, sizeof(struct smb2_lock_element), GFP_KERNEL);
215	if (!buf)
216		return -ENOMEM;
217
218	cur = buf;
219
220	cifs_down_write(&cinode->lock_sem);
221	list_for_each_entry_safe(li, tmp, &cfile->llist->locks, llist) {
222		if (flock->fl_start > li->offset ||
223		    (flock->fl_start + length) <
224		    (li->offset + li->length))
225			continue;
226		if (current->tgid != li->pid)
227			/*
228			 * flock and OFD lock are associated with an open
229			 * file description, not the process.
230			 */
231			if (!(flock->c.flc_flags & (FL_FLOCK | FL_OFDLCK)))
232				continue;
233		if (cinode->can_cache_brlcks) {
234			/*
235			 * We can cache brlock requests - simply remove a lock
236			 * from the file's list.
237			 */
238			list_del(&li->llist);
239			cifs_del_lock_waiters(li);
240			kfree(li);
241			continue;
242		}
243		cur->Length = cpu_to_le64(li->length);
244		cur->Offset = cpu_to_le64(li->offset);
245		cur->Flags = cpu_to_le32(SMB2_LOCKFLAG_UNLOCK);
246		/*
247		 * We need to save a lock here to let us add it again to the
248		 * file's list if the unlock range request fails on the server.
249		 */
250		list_move(&li->llist, &tmp_llist);
251		if (++num == max_num) {
252			stored_rc = smb2_lockv(xid, tcon,
253					       cfile->fid.persistent_fid,
254					       cfile->fid.volatile_fid,
255					       current->tgid, num, buf);
256			if (stored_rc) {
257				/*
258				 * We failed on the unlock range request - add
259				 * all locks from the tmp list to the head of
260				 * the file's list.
261				 */
262				cifs_move_llist(&tmp_llist,
263						&cfile->llist->locks);
264				rc = stored_rc;
265			} else
266				/*
267				 * The unlock range request succeed - free the
268				 * tmp list.
269				 */
270				cifs_free_llist(&tmp_llist);
271			cur = buf;
272			num = 0;
273		} else
274			cur++;
275	}
276	if (num) {
277		stored_rc = smb2_lockv(xid, tcon, cfile->fid.persistent_fid,
278				       cfile->fid.volatile_fid, current->tgid,
279				       num, buf);
280		if (stored_rc) {
281			cifs_move_llist(&tmp_llist, &cfile->llist->locks);
282			rc = stored_rc;
283		} else
284			cifs_free_llist(&tmp_llist);
285	}
286	up_write(&cinode->lock_sem);
287
288	kfree(buf);
289	return rc;
290}
291
292static int
293smb2_push_mand_fdlocks(struct cifs_fid_locks *fdlocks, const unsigned int xid,
294		       struct smb2_lock_element *buf, unsigned int max_num)
295{
296	int rc = 0, stored_rc;
297	struct cifsFileInfo *cfile = fdlocks->cfile;
298	struct cifsLockInfo *li;
299	unsigned int num = 0;
300	struct smb2_lock_element *cur = buf;
301	struct cifs_tcon *tcon = tlink_tcon(cfile->tlink);
302
303	list_for_each_entry(li, &fdlocks->locks, llist) {
304		cur->Length = cpu_to_le64(li->length);
305		cur->Offset = cpu_to_le64(li->offset);
306		cur->Flags = cpu_to_le32(li->type |
307						SMB2_LOCKFLAG_FAIL_IMMEDIATELY);
308		if (++num == max_num) {
309			stored_rc = smb2_lockv(xid, tcon,
310					       cfile->fid.persistent_fid,
311					       cfile->fid.volatile_fid,
312					       current->tgid, num, buf);
313			if (stored_rc)
314				rc = stored_rc;
315			cur = buf;
316			num = 0;
317		} else
318			cur++;
319	}
320	if (num) {
321		stored_rc = smb2_lockv(xid, tcon,
322				       cfile->fid.persistent_fid,
323				       cfile->fid.volatile_fid,
324				       current->tgid, num, buf);
325		if (stored_rc)
326			rc = stored_rc;
327	}
328
329	return rc;
330}
331
332int
333smb2_push_mandatory_locks(struct cifsFileInfo *cfile)
334{
335	int rc = 0, stored_rc;
336	unsigned int xid;
337	unsigned int max_num, max_buf;
338	struct smb2_lock_element *buf;
339	struct cifsInodeInfo *cinode = CIFS_I(d_inode(cfile->dentry));
340	struct cifs_fid_locks *fdlocks;
341
342	xid = get_xid();
343
344	/*
345	 * Accessing maxBuf is racy with cifs_reconnect - need to store value
346	 * and check it for zero before using.
347	 */
348	max_buf = tlink_tcon(cfile->tlink)->ses->server->maxBuf;
349	if (max_buf < sizeof(struct smb2_lock_element)) {
350		free_xid(xid);
351		return -EINVAL;
352	}
353
354	BUILD_BUG_ON(sizeof(struct smb2_lock_element) > PAGE_SIZE);
355	max_buf = min_t(unsigned int, max_buf, PAGE_SIZE);
356	max_num = max_buf / sizeof(struct smb2_lock_element);
357	buf = kcalloc(max_num, sizeof(struct smb2_lock_element), GFP_KERNEL);
358	if (!buf) {
359		free_xid(xid);
360		return -ENOMEM;
361	}
362
363	list_for_each_entry(fdlocks, &cinode->llist, llist) {
364		stored_rc = smb2_push_mand_fdlocks(fdlocks, xid, buf, max_num);
365		if (stored_rc)
366			rc = stored_rc;
367	}
368
369	kfree(buf);
370	free_xid(xid);
371	return rc;
372}
373