smb2file.c

  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
 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	u8 *end = (u8 *)err + iov->iov_len;
 31	u32 len;
 32
 33	if (err->ErrorContextCount) {
 34		struct smb2_error_context_rsp *p;
 35
 36		len = (u32)err->ErrorContextCount * (offsetof(struct smb2_error_context_rsp,
 37							      ErrorContextData) +
 38						     sizeof(struct smb2_symlink_err_rsp));
 39		if (le32_to_cpu(err->ByteCount) < len || iov->iov_len < len + sizeof(*err) + 1)
 40			return ERR_PTR(-EINVAL);
 41
 42		p = (struct smb2_error_context_rsp *)err->ErrorData;
 43		while ((u8 *)p + sizeof(*p) <= end) {
 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 *)(p->ErrorContextData + len);
 53		}
 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) &&
 60	    ((u8 *)sym + sizeof(*sym) > end ||
 61	     le32_to_cpu(sym->SymLinkErrorTag) != SYMLINK_ERROR_TAG ||
 62	     le32_to_cpu(sym->ReparseTag) != IO_REPARSE_TAG_SYMLINK))
 63		sym = ERR_PTR(-EINVAL);
 64
 65	return sym;
 66}
 67
 68int smb2_fix_symlink_target_type(char **target, bool directory, struct cifs_sb_info *cifs_sb)
 69{
 70	char *buf;
 71	int len;
 72
 73	/*
 74	 * POSIX server does not distinguish between symlinks to file and
 75	 * symlink directory. So nothing is needed to fix on the client side.
 76	 */
 77	if (cifs_sb->mnt_cifs_flags & CIFS_MOUNT_POSIX_PATHS)
 78		return 0;
 79
 80	if (!*target)
 81		return smb_EIO(smb_eio_trace_null_pointers);
 82
 83	len = strlen(*target);
 84	if (!len)
 85		return smb_EIO1(smb_eio_trace_sym_target_len, len);
 86
 87	/*
 88	 * If this is directory symlink and it does not have trailing slash then
 89	 * append it. Trailing slash simulates Windows/SMB behavior which do not
 90	 * allow resolving directory symlink to file.
 91	 */
 92	if (directory && (*target)[len-1] != '/') {
 93		buf = krealloc(*target, len+2, GFP_KERNEL);
 94		if (!buf)
 95			return -ENOMEM;
 96		buf[len] = '/';
 97		buf[len+1] = '\0';
 98		*target = buf;
 99		len++;
100	}
101
102	/*
103	 * If this is a file (non-directory) symlink and it points to path name
104	 * with trailing slash then this is an invalid symlink because file name
105	 * cannot contain slash character. File name with slash is invalid on
106	 * both Windows and Linux systems. So return an error for such symlink.
107	 */
108	if (!directory && (*target)[len-1] == '/')
109		return smb_EIO(smb_eio_trace_sym_slash);
110
111	return 0;
112}
113
114int smb2_parse_symlink_response(struct cifs_sb_info *cifs_sb, const struct kvec *iov,
115				const char *full_path, char **path)
116{
117	struct smb2_symlink_err_rsp *sym;
118	unsigned int sub_offs, sub_len;
119	unsigned int print_offs, print_len;
120
121	if (!cifs_sb || !iov || !iov->iov_base || !iov->iov_len || !path)
122		return -EINVAL;
123
124	sym = symlink_data(iov);
125	if (IS_ERR(sym))
126		return PTR_ERR(sym);
127
128	sub_len = le16_to_cpu(sym->SubstituteNameLength);
129	sub_offs = le16_to_cpu(sym->SubstituteNameOffset);
130	print_len = le16_to_cpu(sym->PrintNameLength);
131	print_offs = le16_to_cpu(sym->PrintNameOffset);
132
133	if ((char *)sym->PathBuffer + sub_offs + sub_len >
134		(char *)iov->iov_base + iov->iov_len ||
135	    (char *)sym->PathBuffer + print_offs + print_len >
136		(char *)iov->iov_base + iov->iov_len)
137		return -EINVAL;
138
139	return smb2_parse_native_symlink(path,
140					 (char *)sym->PathBuffer + sub_offs,
141					 sub_len,
142					 le32_to_cpu(sym->Flags) & SYMLINK_FLAG_RELATIVE,
143					 full_path,
144					 cifs_sb);
145}
146
147int smb2_open_file(const unsigned int xid, struct cifs_open_parms *oparms,
148		   __u32 *oplock, void *buf)
149{
150	int rc;
151	__le16 *smb2_path;
152	__u8 smb2_oplock;
153	struct cifs_open_info_data *data = buf;
154	struct smb2_file_all_info file_info = {};
155	struct smb2_file_all_info *smb2_data = data ? &file_info : NULL;
156	struct kvec err_iov = {};
157	int err_buftype = CIFS_NO_BUFFER;
158	struct cifs_fid *fid = oparms->fid;
159	struct network_resiliency_req nr_ioctl_req;
160	bool retry_without_read_attributes = false;
161
162	smb2_path = cifs_convert_path_to_utf16(oparms->path, oparms->cifs_sb);
163	if (smb2_path == NULL)
164		return -ENOMEM;
165
166	/*
167	 * GENERIC_READ, GENERIC_EXECUTE, GENERIC_ALL and MAXIMUM_ALLOWED
168	 * contains also FILE_READ_ATTRIBUTES access right. So do not append
169	 * FILE_READ_ATTRIBUTES when not needed and prevent calling code path
170	 * for retry_without_read_attributes.
171	 */
172	if (!(oparms->desired_access & FILE_READ_ATTRIBUTES) &&
173	    !(oparms->desired_access & GENERIC_READ) &&
174	    !(oparms->desired_access & GENERIC_EXECUTE) &&
175	    !(oparms->desired_access & GENERIC_ALL) &&
176	    !(oparms->desired_access & MAXIMUM_ALLOWED)) {
177		oparms->desired_access |= FILE_READ_ATTRIBUTES;
178		retry_without_read_attributes = true;
179	}
180	smb2_oplock = SMB2_OPLOCK_LEVEL_BATCH;
181
182	rc = SMB2_open(xid, oparms, smb2_path, &smb2_oplock, smb2_data, NULL, &err_iov,
183		       &err_buftype);
184	if (rc == -EACCES && retry_without_read_attributes) {
185		free_rsp_buf(err_buftype, err_iov.iov_base);
186		memset(&err_iov, 0, sizeof(err_iov));
187		err_buftype = CIFS_NO_BUFFER;
188		oparms->desired_access &= ~FILE_READ_ATTRIBUTES;
189		rc = SMB2_open(xid, oparms, smb2_path, &smb2_oplock, smb2_data, NULL, &err_iov,
190			       &err_buftype);
191	}
192	if (rc && data) {
193		struct smb2_hdr *hdr = err_iov.iov_base;
194
195		if (unlikely(!err_iov.iov_base || err_buftype == CIFS_NO_BUFFER))
196			goto out;
197		if (hdr->Status == STATUS_STOPPED_ON_SYMLINK) {
198			rc = smb2_parse_symlink_response(oparms->cifs_sb, &err_iov,
199							 oparms->path,
200							 &data->symlink_target);
201			if (!rc) {
202				memset(smb2_data, 0, sizeof(*smb2_data));
203				oparms->create_options |= OPEN_REPARSE_POINT;
204				rc = SMB2_open(xid, oparms, smb2_path, &smb2_oplock, smb2_data,
205					       NULL, NULL, NULL);
206				oparms->create_options &= ~OPEN_REPARSE_POINT;
207			}
208			if (!rc) {
209				bool directory = le32_to_cpu(data->fi.Attributes) & ATTR_DIRECTORY;
210				rc = smb2_fix_symlink_target_type(&data->symlink_target,
211								  directory, oparms->cifs_sb);
212			}
213		}
214	}
215
216	if (rc)
217		goto out;
218
219	if (oparms->tcon->use_resilient) {
220		/* default timeout is 0, servers pick default (120 seconds) */
221		nr_ioctl_req.Timeout =
222			cpu_to_le32(oparms->tcon->handle_timeout);
223		nr_ioctl_req.Reserved = 0;
224		rc = SMB2_ioctl(xid, oparms->tcon, fid->persistent_fid,
225			fid->volatile_fid, FSCTL_LMR_REQUEST_RESILIENCY,
226			(char *)&nr_ioctl_req, sizeof(nr_ioctl_req),
227			CIFSMaxBufSize, NULL, NULL /* no return info */);
228		if (rc == -EOPNOTSUPP) {
229			cifs_dbg(VFS,
230			     "resiliency not supported by server, disabling\n");
231			oparms->tcon->use_resilient = false;
232		} else if (rc)
233			cifs_dbg(FYI, "error %d setting resiliency\n", rc);
234
235		rc = 0;
236	}
237
238	if (smb2_data) {
239		/* if open response does not have IndexNumber field - get it */
240		if (smb2_data->IndexNumber == 0) {
241			rc = SMB2_get_srv_num(xid, oparms->tcon,
242				      fid->persistent_fid,
243				      fid->volatile_fid,
244				      &smb2_data->IndexNumber);
245			if (rc) {
246				/*
247				 * let get_inode_info disable server inode
248				 * numbers
249				 */
250				smb2_data->IndexNumber = 0;
251				rc = 0;
252			}
253		}
254		memcpy(&data->fi, smb2_data, sizeof(data->fi));
255	}
256
257	*oplock = smb2_oplock;
258out:
259	free_rsp_buf(err_buftype, err_iov.iov_base);
260	kfree(smb2_path);
261	return rc;
262}
263
264int
265smb2_unlock_range(struct cifsFileInfo *cfile, struct file_lock *flock,
266		  const unsigned int xid)
267{
268	int rc = 0, stored_rc;
269	unsigned int max_num, num = 0, max_buf;
270	struct smb2_lock_element *buf, *cur;
271	struct cifs_tcon *tcon = tlink_tcon(cfile->tlink);
272	struct cifsInodeInfo *cinode = CIFS_I(d_inode(cfile->dentry));
273	struct cifsLockInfo *li, *tmp;
274	__u64 length = 1 + flock->fl_end - flock->fl_start;
275	LIST_HEAD(tmp_llist);
276
277	/*
278	 * Accessing maxBuf is racy with cifs_reconnect - need to store value
279	 * and check it before using.
280	 */
281	max_buf = tcon->ses->server->maxBuf;
282	if (max_buf < sizeof(struct smb2_lock_element))
283		return -EINVAL;
284
285	BUILD_BUG_ON(sizeof(struct smb2_lock_element) > PAGE_SIZE);
286	max_buf = min_t(unsigned int, max_buf, PAGE_SIZE);
287	max_num = max_buf / sizeof(struct smb2_lock_element);
288	buf = kcalloc(max_num, sizeof(struct smb2_lock_element), GFP_KERNEL);
289	if (!buf)
290		return -ENOMEM;
291
292	cur = buf;
293
294	cifs_down_write(&cinode->lock_sem);
295	list_for_each_entry_safe(li, tmp, &cfile->llist->locks, llist) {
296		if (flock->fl_start > li->offset ||
297		    (flock->fl_start + length) <
298		    (li->offset + li->length))
299			continue;
300		if (current->tgid != li->pid)
301			/*
302			 * flock and OFD lock are associated with an open
303			 * file description, not the process.
304			 */
305			if (!(flock->c.flc_flags & (FL_FLOCK | FL_OFDLCK)))
306				continue;
307		if (cinode->can_cache_brlcks) {
308			/*
309			 * We can cache brlock requests - simply remove a lock
310			 * from the file's list.
311			 */
312			list_del(&li->llist);
313			cifs_del_lock_waiters(li);
314			kfree(li);
315			continue;
316		}
317		cur->Length = cpu_to_le64(li->length);
318		cur->Offset = cpu_to_le64(li->offset);
319		cur->Flags = cpu_to_le32(SMB2_LOCKFLAG_UNLOCK);
320		/*
321		 * We need to save a lock here to let us add it again to the
322		 * file's list if the unlock range request fails on the server.
323		 */
324		list_move(&li->llist, &tmp_llist);
325		if (++num == max_num) {
326			stored_rc = smb2_lockv(xid, tcon,
327					       cfile->fid.persistent_fid,
328					       cfile->fid.volatile_fid,
329					       current->tgid, num, buf);
330			if (stored_rc) {
331				/*
332				 * We failed on the unlock range request - add
333				 * all locks from the tmp list to the head of
334				 * the file's list.
335				 */
336				cifs_move_llist(&tmp_llist,
337						&cfile->llist->locks);
338				rc = stored_rc;
339			} else
340				/*
341				 * The unlock range request succeed - free the
342				 * tmp list.
343				 */
344				cifs_free_llist(&tmp_llist);
345			cur = buf;
346			num = 0;
347		} else
348			cur++;
349	}
350	if (num) {
351		stored_rc = smb2_lockv(xid, tcon, cfile->fid.persistent_fid,
352				       cfile->fid.volatile_fid, current->tgid,
353				       num, buf);
354		if (stored_rc) {
355			cifs_move_llist(&tmp_llist, &cfile->llist->locks);
356			rc = stored_rc;
357		} else
358			cifs_free_llist(&tmp_llist);
359	}
360	up_write(&cinode->lock_sem);
361
362	kfree(buf);
363	return rc;
364}
365
366static int
367smb2_push_mand_fdlocks(struct cifs_fid_locks *fdlocks, const unsigned int xid,
368		       struct smb2_lock_element *buf, unsigned int max_num)
369{
370	int rc = 0, stored_rc;
371	struct cifsFileInfo *cfile = fdlocks->cfile;
372	struct cifsLockInfo *li;
373	unsigned int num = 0;
374	struct smb2_lock_element *cur = buf;
375	struct cifs_tcon *tcon = tlink_tcon(cfile->tlink);
376
377	list_for_each_entry(li, &fdlocks->locks, llist) {
378		cur->Length = cpu_to_le64(li->length);
379		cur->Offset = cpu_to_le64(li->offset);
380		cur->Flags = cpu_to_le32(li->type |
381						SMB2_LOCKFLAG_FAIL_IMMEDIATELY);
382		if (++num == max_num) {
383			stored_rc = smb2_lockv(xid, tcon,
384					       cfile->fid.persistent_fid,
385					       cfile->fid.volatile_fid,
386					       current->tgid, num, buf);
387			if (stored_rc)
388				rc = stored_rc;
389			cur = buf;
390			num = 0;
391		} else
392			cur++;
393	}
394	if (num) {
395		stored_rc = smb2_lockv(xid, tcon,
396				       cfile->fid.persistent_fid,
397				       cfile->fid.volatile_fid,
398				       current->tgid, num, buf);
399		if (stored_rc)
400			rc = stored_rc;
401	}
402
403	return rc;
404}
405
406int
407smb2_push_mandatory_locks(struct cifsFileInfo *cfile)
408{
409	int rc = 0, stored_rc;
410	unsigned int xid;
411	unsigned int max_num, max_buf;
412	struct smb2_lock_element *buf;
413	struct cifsInodeInfo *cinode = CIFS_I(d_inode(cfile->dentry));
414	struct cifs_fid_locks *fdlocks;
415
416	xid = get_xid();
417
418	/*
419	 * Accessing maxBuf is racy with cifs_reconnect - need to store value
420	 * and check it for zero before using.
421	 */
422	max_buf = tlink_tcon(cfile->tlink)->ses->server->maxBuf;
423	if (max_buf < sizeof(struct smb2_lock_element)) {
424		free_xid(xid);
425		return -EINVAL;
426	}
427
428	BUILD_BUG_ON(sizeof(struct smb2_lock_element) > PAGE_SIZE);
429	max_buf = min_t(unsigned int, max_buf, PAGE_SIZE);
430	max_num = max_buf / sizeof(struct smb2_lock_element);
431	buf = kcalloc(max_num, sizeof(struct smb2_lock_element), GFP_KERNEL);
432	if (!buf) {
433		free_xid(xid);
434		return -ENOMEM;
435	}
436
437	list_for_each_entry(fdlocks, &cinode->llist, llist) {
438		stored_rc = smb2_push_mand_fdlocks(fdlocks, xid, buf, max_num);
439		if (stored_rc)
440			rc = stored_rc;
441	}
442
443	kfree(buf);
444	free_xid(xid);
445	return rc;
446}