xref: /linux/fs/smb/client/smb2file.c (revision 0235da0faeeec1c1ce2265fc627f5d5d9cae7ce8)
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 "../common/smb2status.h"
25 
symlink_data(const struct kvec * iov)26 static 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 
smb2_parse_symlink_response(struct cifs_sb_info * cifs_sb,const struct kvec * iov,const char * full_path,char ** path)66 int smb2_parse_symlink_response(struct cifs_sb_info *cifs_sb, const struct kvec *iov,
67 				const char *full_path, char **path)
68 {
69 	struct smb2_symlink_err_rsp *sym;
70 	unsigned int sub_offs, sub_len;
71 	unsigned int print_offs, print_len;
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 	return smb2_parse_native_symlink(path,
90 					 (char *)sym->PathBuffer + sub_offs,
91 					 sub_len,
92 					 true,
93 					 le32_to_cpu(sym->Flags) & SYMLINK_FLAG_RELATIVE,
94 					 full_path,
95 					 cifs_sb);
96 }
97 
smb2_open_file(const unsigned int xid,struct cifs_open_parms * oparms,__u32 * oplock,void * buf)98 int smb2_open_file(const unsigned int xid, struct cifs_open_parms *oparms, __u32 *oplock, void *buf)
99 {
100 	int rc;
101 	__le16 *smb2_path;
102 	__u8 smb2_oplock;
103 	struct cifs_open_info_data *data = buf;
104 	struct smb2_file_all_info file_info = {};
105 	struct smb2_file_all_info *smb2_data = data ? &file_info : NULL;
106 	struct kvec err_iov = {};
107 	int err_buftype = CIFS_NO_BUFFER;
108 	struct cifs_fid *fid = oparms->fid;
109 	struct network_resiliency_req nr_ioctl_req;
110 
111 	smb2_path = cifs_convert_path_to_utf16(oparms->path, oparms->cifs_sb);
112 	if (smb2_path == NULL)
113 		return -ENOMEM;
114 
115 	oparms->desired_access |= FILE_READ_ATTRIBUTES;
116 	smb2_oplock = SMB2_OPLOCK_LEVEL_BATCH;
117 
118 	rc = SMB2_open(xid, oparms, smb2_path, &smb2_oplock, smb2_data, NULL, &err_iov,
119 		       &err_buftype);
120 	if (rc && data) {
121 		struct smb2_hdr *hdr = err_iov.iov_base;
122 
123 		if (unlikely(!err_iov.iov_base || err_buftype == CIFS_NO_BUFFER))
124 			goto out;
125 		if (hdr->Status == STATUS_STOPPED_ON_SYMLINK) {
126 			rc = smb2_parse_symlink_response(oparms->cifs_sb, &err_iov,
127 							 oparms->path,
128 							 &data->symlink_target);
129 			if (!rc) {
130 				memset(smb2_data, 0, sizeof(*smb2_data));
131 				oparms->create_options |= OPEN_REPARSE_POINT;
132 				rc = SMB2_open(xid, oparms, smb2_path, &smb2_oplock, smb2_data,
133 					       NULL, NULL, NULL);
134 				oparms->create_options &= ~OPEN_REPARSE_POINT;
135 			}
136 		}
137 	}
138 
139 	if (rc)
140 		goto out;
141 
142 	if (oparms->tcon->use_resilient) {
143 		/* default timeout is 0, servers pick default (120 seconds) */
144 		nr_ioctl_req.Timeout =
145 			cpu_to_le32(oparms->tcon->handle_timeout);
146 		nr_ioctl_req.Reserved = 0;
147 		rc = SMB2_ioctl(xid, oparms->tcon, fid->persistent_fid,
148 			fid->volatile_fid, FSCTL_LMR_REQUEST_RESILIENCY,
149 			(char *)&nr_ioctl_req, sizeof(nr_ioctl_req),
150 			CIFSMaxBufSize, NULL, NULL /* no return info */);
151 		if (rc == -EOPNOTSUPP) {
152 			cifs_dbg(VFS,
153 			     "resiliency not supported by server, disabling\n");
154 			oparms->tcon->use_resilient = false;
155 		} else if (rc)
156 			cifs_dbg(FYI, "error %d setting resiliency\n", rc);
157 
158 		rc = 0;
159 	}
160 
161 	if (smb2_data) {
162 		/* if open response does not have IndexNumber field - get it */
163 		if (smb2_data->IndexNumber == 0) {
164 			rc = SMB2_get_srv_num(xid, oparms->tcon,
165 				      fid->persistent_fid,
166 				      fid->volatile_fid,
167 				      &smb2_data->IndexNumber);
168 			if (rc) {
169 				/*
170 				 * let get_inode_info disable server inode
171 				 * numbers
172 				 */
173 				smb2_data->IndexNumber = 0;
174 				rc = 0;
175 			}
176 		}
177 		memcpy(&data->fi, smb2_data, sizeof(data->fi));
178 	}
179 
180 	*oplock = smb2_oplock;
181 out:
182 	free_rsp_buf(err_buftype, err_iov.iov_base);
183 	kfree(smb2_path);
184 	return rc;
185 }
186 
187 int
smb2_unlock_range(struct cifsFileInfo * cfile,struct file_lock * flock,const unsigned int xid)188 smb2_unlock_range(struct cifsFileInfo *cfile, struct file_lock *flock,
189 		  const unsigned int xid)
190 {
191 	int rc = 0, stored_rc;
192 	unsigned int max_num, num = 0, max_buf;
193 	struct smb2_lock_element *buf, *cur;
194 	struct cifs_tcon *tcon = tlink_tcon(cfile->tlink);
195 	struct cifsInodeInfo *cinode = CIFS_I(d_inode(cfile->dentry));
196 	struct cifsLockInfo *li, *tmp;
197 	__u64 length = 1 + flock->fl_end - flock->fl_start;
198 	LIST_HEAD(tmp_llist);
199 
200 	/*
201 	 * Accessing maxBuf is racy with cifs_reconnect - need to store value
202 	 * and check it before using.
203 	 */
204 	max_buf = tcon->ses->server->maxBuf;
205 	if (max_buf < sizeof(struct smb2_lock_element))
206 		return -EINVAL;
207 
208 	BUILD_BUG_ON(sizeof(struct smb2_lock_element) > PAGE_SIZE);
209 	max_buf = min_t(unsigned int, max_buf, PAGE_SIZE);
210 	max_num = max_buf / sizeof(struct smb2_lock_element);
211 	buf = kcalloc(max_num, sizeof(struct smb2_lock_element), GFP_KERNEL);
212 	if (!buf)
213 		return -ENOMEM;
214 
215 	cur = buf;
216 
217 	cifs_down_write(&cinode->lock_sem);
218 	list_for_each_entry_safe(li, tmp, &cfile->llist->locks, llist) {
219 		if (flock->fl_start > li->offset ||
220 		    (flock->fl_start + length) <
221 		    (li->offset + li->length))
222 			continue;
223 		if (current->tgid != li->pid)
224 			/*
225 			 * flock and OFD lock are associated with an open
226 			 * file description, not the process.
227 			 */
228 			if (!(flock->c.flc_flags & (FL_FLOCK | FL_OFDLCK)))
229 				continue;
230 		if (cinode->can_cache_brlcks) {
231 			/*
232 			 * We can cache brlock requests - simply remove a lock
233 			 * from the file's list.
234 			 */
235 			list_del(&li->llist);
236 			cifs_del_lock_waiters(li);
237 			kfree(li);
238 			continue;
239 		}
240 		cur->Length = cpu_to_le64(li->length);
241 		cur->Offset = cpu_to_le64(li->offset);
242 		cur->Flags = cpu_to_le32(SMB2_LOCKFLAG_UNLOCK);
243 		/*
244 		 * We need to save a lock here to let us add it again to the
245 		 * file's list if the unlock range request fails on the server.
246 		 */
247 		list_move(&li->llist, &tmp_llist);
248 		if (++num == max_num) {
249 			stored_rc = smb2_lockv(xid, tcon,
250 					       cfile->fid.persistent_fid,
251 					       cfile->fid.volatile_fid,
252 					       current->tgid, num, buf);
253 			if (stored_rc) {
254 				/*
255 				 * We failed on the unlock range request - add
256 				 * all locks from the tmp list to the head of
257 				 * the file's list.
258 				 */
259 				cifs_move_llist(&tmp_llist,
260 						&cfile->llist->locks);
261 				rc = stored_rc;
262 			} else
263 				/*
264 				 * The unlock range request succeed - free the
265 				 * tmp list.
266 				 */
267 				cifs_free_llist(&tmp_llist);
268 			cur = buf;
269 			num = 0;
270 		} else
271 			cur++;
272 	}
273 	if (num) {
274 		stored_rc = smb2_lockv(xid, tcon, cfile->fid.persistent_fid,
275 				       cfile->fid.volatile_fid, current->tgid,
276 				       num, buf);
277 		if (stored_rc) {
278 			cifs_move_llist(&tmp_llist, &cfile->llist->locks);
279 			rc = stored_rc;
280 		} else
281 			cifs_free_llist(&tmp_llist);
282 	}
283 	up_write(&cinode->lock_sem);
284 
285 	kfree(buf);
286 	return rc;
287 }
288 
289 static int
smb2_push_mand_fdlocks(struct cifs_fid_locks * fdlocks,const unsigned int xid,struct smb2_lock_element * buf,unsigned int max_num)290 smb2_push_mand_fdlocks(struct cifs_fid_locks *fdlocks, const unsigned int xid,
291 		       struct smb2_lock_element *buf, unsigned int max_num)
292 {
293 	int rc = 0, stored_rc;
294 	struct cifsFileInfo *cfile = fdlocks->cfile;
295 	struct cifsLockInfo *li;
296 	unsigned int num = 0;
297 	struct smb2_lock_element *cur = buf;
298 	struct cifs_tcon *tcon = tlink_tcon(cfile->tlink);
299 
300 	list_for_each_entry(li, &fdlocks->locks, llist) {
301 		cur->Length = cpu_to_le64(li->length);
302 		cur->Offset = cpu_to_le64(li->offset);
303 		cur->Flags = cpu_to_le32(li->type |
304 						SMB2_LOCKFLAG_FAIL_IMMEDIATELY);
305 		if (++num == max_num) {
306 			stored_rc = smb2_lockv(xid, tcon,
307 					       cfile->fid.persistent_fid,
308 					       cfile->fid.volatile_fid,
309 					       current->tgid, num, buf);
310 			if (stored_rc)
311 				rc = stored_rc;
312 			cur = buf;
313 			num = 0;
314 		} else
315 			cur++;
316 	}
317 	if (num) {
318 		stored_rc = smb2_lockv(xid, tcon,
319 				       cfile->fid.persistent_fid,
320 				       cfile->fid.volatile_fid,
321 				       current->tgid, num, buf);
322 		if (stored_rc)
323 			rc = stored_rc;
324 	}
325 
326 	return rc;
327 }
328 
329 int
smb2_push_mandatory_locks(struct cifsFileInfo * cfile)330 smb2_push_mandatory_locks(struct cifsFileInfo *cfile)
331 {
332 	int rc = 0, stored_rc;
333 	unsigned int xid;
334 	unsigned int max_num, max_buf;
335 	struct smb2_lock_element *buf;
336 	struct cifsInodeInfo *cinode = CIFS_I(d_inode(cfile->dentry));
337 	struct cifs_fid_locks *fdlocks;
338 
339 	xid = get_xid();
340 
341 	/*
342 	 * Accessing maxBuf is racy with cifs_reconnect - need to store value
343 	 * and check it for zero before using.
344 	 */
345 	max_buf = tlink_tcon(cfile->tlink)->ses->server->maxBuf;
346 	if (max_buf < sizeof(struct smb2_lock_element)) {
347 		free_xid(xid);
348 		return -EINVAL;
349 	}
350 
351 	BUILD_BUG_ON(sizeof(struct smb2_lock_element) > PAGE_SIZE);
352 	max_buf = min_t(unsigned int, max_buf, PAGE_SIZE);
353 	max_num = max_buf / sizeof(struct smb2_lock_element);
354 	buf = kcalloc(max_num, sizeof(struct smb2_lock_element), GFP_KERNEL);
355 	if (!buf) {
356 		free_xid(xid);
357 		return -ENOMEM;
358 	}
359 
360 	list_for_each_entry(fdlocks, &cinode->llist, llist) {
361 		stored_rc = smb2_push_mand_fdlocks(fdlocks, xid, buf, max_num);
362 		if (stored_rc)
363 			rc = stored_rc;
364 	}
365 
366 	kfree(buf);
367 	free_xid(xid);
368 	return rc;
369 }
370