xref: /openbmc/linux/fs/smb/client/fs_context.c (revision c1e0230e)
1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3  *   Copyright (C) 2020, Microsoft Corporation.
4  *
5  *   Author(s): Steve French <stfrench@microsoft.com>
6  *              David Howells <dhowells@redhat.com>
7  */
8 
9 /*
10 #include <linux/module.h>
11 #include <linux/nsproxy.h>
12 #include <linux/slab.h>
13 #include <linux/magic.h>
14 #include <linux/security.h>
15 #include <net/net_namespace.h>
16 #ifdef CONFIG_CIFS_DFS_UPCALL
17 #include "dfs_cache.h"
18 #endif
19 */
20 
21 #include <linux/ctype.h>
22 #include <linux/fs_context.h>
23 #include <linux/fs_parser.h>
24 #include <linux/fs.h>
25 #include <linux/mount.h>
26 #include <linux/parser.h>
27 #include <linux/utsname.h>
28 #include "cifsfs.h"
29 #include "cifspdu.h"
30 #include "cifsglob.h"
31 #include "cifsproto.h"
32 #include "cifs_unicode.h"
33 #include "cifs_debug.h"
34 #include "cifs_fs_sb.h"
35 #include "ntlmssp.h"
36 #include "nterr.h"
37 #include "rfc1002pdu.h"
38 #include "fs_context.h"
39 
40 static DEFINE_MUTEX(cifs_mount_mutex);
41 
42 static const match_table_t cifs_smb_version_tokens = {
43 	{ Smb_1, SMB1_VERSION_STRING },
44 	{ Smb_20, SMB20_VERSION_STRING},
45 	{ Smb_21, SMB21_VERSION_STRING },
46 	{ Smb_30, SMB30_VERSION_STRING },
47 	{ Smb_302, SMB302_VERSION_STRING },
48 	{ Smb_302, ALT_SMB302_VERSION_STRING },
49 	{ Smb_311, SMB311_VERSION_STRING },
50 	{ Smb_311, ALT_SMB311_VERSION_STRING },
51 	{ Smb_3any, SMB3ANY_VERSION_STRING },
52 	{ Smb_default, SMBDEFAULT_VERSION_STRING },
53 	{ Smb_version_err, NULL }
54 };
55 
56 static const match_table_t cifs_secflavor_tokens = {
57 	{ Opt_sec_krb5, "krb5" },
58 	{ Opt_sec_krb5i, "krb5i" },
59 	{ Opt_sec_krb5p, "krb5p" },
60 	{ Opt_sec_ntlmsspi, "ntlmsspi" },
61 	{ Opt_sec_ntlmssp, "ntlmssp" },
62 	{ Opt_sec_ntlmv2, "nontlm" },
63 	{ Opt_sec_ntlmv2, "ntlmv2" },
64 	{ Opt_sec_ntlmv2i, "ntlmv2i" },
65 	{ Opt_sec_none, "none" },
66 
67 	{ Opt_sec_err, NULL }
68 };
69 
70 const struct fs_parameter_spec smb3_fs_parameters[] = {
71 	/* Mount options that take no arguments */
72 	fsparam_flag_no("user_xattr", Opt_user_xattr),
73 	fsparam_flag_no("forceuid", Opt_forceuid),
74 	fsparam_flag_no("multichannel", Opt_multichannel),
75 	fsparam_flag_no("forcegid", Opt_forcegid),
76 	fsparam_flag("noblocksend", Opt_noblocksend),
77 	fsparam_flag("noautotune", Opt_noautotune),
78 	fsparam_flag("nolease", Opt_nolease),
79 	fsparam_flag_no("hard", Opt_hard),
80 	fsparam_flag_no("soft", Opt_soft),
81 	fsparam_flag_no("perm", Opt_perm),
82 	fsparam_flag("nodelete", Opt_nodelete),
83 	fsparam_flag_no("mapposix", Opt_mapposix),
84 	fsparam_flag("mapchars", Opt_mapchars),
85 	fsparam_flag("nomapchars", Opt_nomapchars),
86 	fsparam_flag_no("sfu", Opt_sfu),
87 	fsparam_flag("nodfs", Opt_nodfs),
88 	fsparam_flag_no("posixpaths", Opt_posixpaths),
89 	fsparam_flag_no("unix", Opt_unix),
90 	fsparam_flag_no("linux", Opt_unix),
91 	fsparam_flag_no("posix", Opt_unix),
92 	fsparam_flag("nocase", Opt_nocase),
93 	fsparam_flag("ignorecase", Opt_nocase),
94 	fsparam_flag_no("brl", Opt_brl),
95 	fsparam_flag_no("handlecache", Opt_handlecache),
96 	fsparam_flag("forcemandatorylock", Opt_forcemandatorylock),
97 	fsparam_flag("forcemand", Opt_forcemandatorylock),
98 	fsparam_flag("setuidfromacl", Opt_setuidfromacl),
99 	fsparam_flag("idsfromsid", Opt_setuidfromacl),
100 	fsparam_flag_no("setuids", Opt_setuids),
101 	fsparam_flag_no("dynperm", Opt_dynperm),
102 	fsparam_flag_no("intr", Opt_intr),
103 	fsparam_flag_no("strictsync", Opt_strictsync),
104 	fsparam_flag_no("serverino", Opt_serverino),
105 	fsparam_flag("rwpidforward", Opt_rwpidforward),
106 	fsparam_flag("cifsacl", Opt_cifsacl),
107 	fsparam_flag_no("acl", Opt_acl),
108 	fsparam_flag("locallease", Opt_locallease),
109 	fsparam_flag("sign", Opt_sign),
110 	fsparam_flag("ignore_signature", Opt_ignore_signature),
111 	fsparam_flag("signloosely", Opt_ignore_signature),
112 	fsparam_flag("seal", Opt_seal),
113 	fsparam_flag("noac", Opt_noac),
114 	fsparam_flag("fsc", Opt_fsc),
115 	fsparam_flag("mfsymlinks", Opt_mfsymlinks),
116 	fsparam_flag("multiuser", Opt_multiuser),
117 	fsparam_flag("sloppy", Opt_sloppy),
118 	fsparam_flag("nosharesock", Opt_nosharesock),
119 	fsparam_flag_no("persistenthandles", Opt_persistent),
120 	fsparam_flag_no("resilienthandles", Opt_resilient),
121 	fsparam_flag_no("tcpnodelay", Opt_tcp_nodelay),
122 	fsparam_flag("nosparse", Opt_nosparse),
123 	fsparam_flag("domainauto", Opt_domainauto),
124 	fsparam_flag("rdma", Opt_rdma),
125 	fsparam_flag("modesid", Opt_modesid),
126 	fsparam_flag("modefromsid", Opt_modesid),
127 	fsparam_flag("rootfs", Opt_rootfs),
128 	fsparam_flag("compress", Opt_compress),
129 	fsparam_flag("witness", Opt_witness),
130 
131 	/* Mount options which take numeric value */
132 	fsparam_u32("backupuid", Opt_backupuid),
133 	fsparam_u32("backupgid", Opt_backupgid),
134 	fsparam_u32("uid", Opt_uid),
135 	fsparam_u32("cruid", Opt_cruid),
136 	fsparam_u32("gid", Opt_gid),
137 	fsparam_u32("file_mode", Opt_file_mode),
138 	fsparam_u32("dirmode", Opt_dirmode),
139 	fsparam_u32("dir_mode", Opt_dirmode),
140 	fsparam_u32("port", Opt_port),
141 	fsparam_u32("min_enc_offload", Opt_min_enc_offload),
142 	fsparam_u32("esize", Opt_min_enc_offload),
143 	fsparam_u32("bsize", Opt_blocksize),
144 	fsparam_u32("rasize", Opt_rasize),
145 	fsparam_u32("rsize", Opt_rsize),
146 	fsparam_u32("wsize", Opt_wsize),
147 	fsparam_u32("actimeo", Opt_actimeo),
148 	fsparam_u32("acdirmax", Opt_acdirmax),
149 	fsparam_u32("acregmax", Opt_acregmax),
150 	fsparam_u32("closetimeo", Opt_closetimeo),
151 	fsparam_u32("echo_interval", Opt_echo_interval),
152 	fsparam_u32("max_credits", Opt_max_credits),
153 	fsparam_u32("handletimeout", Opt_handletimeout),
154 	fsparam_u64("snapshot", Opt_snapshot),
155 	fsparam_u32("max_channels", Opt_max_channels),
156 
157 	/* Mount options which take string value */
158 	fsparam_string("source", Opt_source),
159 	fsparam_string("user", Opt_user),
160 	fsparam_string("username", Opt_user),
161 	fsparam_string("pass", Opt_pass),
162 	fsparam_string("password", Opt_pass),
163 	fsparam_string("ip", Opt_ip),
164 	fsparam_string("addr", Opt_ip),
165 	fsparam_string("domain", Opt_domain),
166 	fsparam_string("dom", Opt_domain),
167 	fsparam_string("srcaddr", Opt_srcaddr),
168 	fsparam_string("iocharset", Opt_iocharset),
169 	fsparam_string("netbiosname", Opt_netbiosname),
170 	fsparam_string("servern", Opt_servern),
171 	fsparam_string("ver", Opt_ver),
172 	fsparam_string("vers", Opt_vers),
173 	fsparam_string("sec", Opt_sec),
174 	fsparam_string("cache", Opt_cache),
175 
176 	/* Arguments that should be ignored */
177 	fsparam_flag("guest", Opt_ignore),
178 	fsparam_flag("noatime", Opt_ignore),
179 	fsparam_flag("relatime", Opt_ignore),
180 	fsparam_flag("_netdev", Opt_ignore),
181 	fsparam_flag_no("suid", Opt_ignore),
182 	fsparam_flag_no("exec", Opt_ignore),
183 	fsparam_flag_no("dev", Opt_ignore),
184 	fsparam_flag_no("mand", Opt_ignore),
185 	fsparam_flag_no("auto", Opt_ignore),
186 	fsparam_string("cred", Opt_ignore),
187 	fsparam_string("credentials", Opt_ignore),
188 	/*
189 	 * UNC and prefixpath is now extracted from Opt_source
190 	 * in the new mount API so we can just ignore them going forward.
191 	 */
192 	fsparam_string("unc", Opt_ignore),
193 	fsparam_string("prefixpath", Opt_ignore),
194 	{}
195 };
196 
197 static int
198 cifs_parse_security_flavors(struct fs_context *fc, char *value, struct smb3_fs_context *ctx)
199 {
200 
201 	substring_t args[MAX_OPT_ARGS];
202 
203 	/*
204 	 * With mount options, the last one should win. Reset any existing
205 	 * settings back to default.
206 	 */
207 	ctx->sectype = Unspecified;
208 	ctx->sign = false;
209 
210 	switch (match_token(value, cifs_secflavor_tokens, args)) {
211 	case Opt_sec_krb5p:
212 		cifs_errorf(fc, "sec=krb5p is not supported!\n");
213 		return 1;
214 	case Opt_sec_krb5i:
215 		ctx->sign = true;
216 		fallthrough;
217 	case Opt_sec_krb5:
218 		ctx->sectype = Kerberos;
219 		break;
220 	case Opt_sec_ntlmsspi:
221 		ctx->sign = true;
222 		fallthrough;
223 	case Opt_sec_ntlmssp:
224 		ctx->sectype = RawNTLMSSP;
225 		break;
226 	case Opt_sec_ntlmv2i:
227 		ctx->sign = true;
228 		fallthrough;
229 	case Opt_sec_ntlmv2:
230 		ctx->sectype = NTLMv2;
231 		break;
232 	case Opt_sec_none:
233 		ctx->nullauth = 1;
234 		kfree(ctx->username);
235 		ctx->username = NULL;
236 		break;
237 	default:
238 		cifs_errorf(fc, "bad security option: %s\n", value);
239 		return 1;
240 	}
241 
242 	return 0;
243 }
244 
245 static const match_table_t cifs_cacheflavor_tokens = {
246 	{ Opt_cache_loose, "loose" },
247 	{ Opt_cache_strict, "strict" },
248 	{ Opt_cache_none, "none" },
249 	{ Opt_cache_ro, "ro" },
250 	{ Opt_cache_rw, "singleclient" },
251 	{ Opt_cache_err, NULL }
252 };
253 
254 static int
255 cifs_parse_cache_flavor(struct fs_context *fc, char *value, struct smb3_fs_context *ctx)
256 {
257 	substring_t args[MAX_OPT_ARGS];
258 
259 	switch (match_token(value, cifs_cacheflavor_tokens, args)) {
260 	case Opt_cache_loose:
261 		ctx->direct_io = false;
262 		ctx->strict_io = false;
263 		ctx->cache_ro = false;
264 		ctx->cache_rw = false;
265 		break;
266 	case Opt_cache_strict:
267 		ctx->direct_io = false;
268 		ctx->strict_io = true;
269 		ctx->cache_ro = false;
270 		ctx->cache_rw = false;
271 		break;
272 	case Opt_cache_none:
273 		ctx->direct_io = true;
274 		ctx->strict_io = false;
275 		ctx->cache_ro = false;
276 		ctx->cache_rw = false;
277 		break;
278 	case Opt_cache_ro:
279 		ctx->direct_io = false;
280 		ctx->strict_io = false;
281 		ctx->cache_ro = true;
282 		ctx->cache_rw = false;
283 		break;
284 	case Opt_cache_rw:
285 		ctx->direct_io = false;
286 		ctx->strict_io = false;
287 		ctx->cache_ro = false;
288 		ctx->cache_rw = true;
289 		break;
290 	default:
291 		cifs_errorf(fc, "bad cache= option: %s\n", value);
292 		return 1;
293 	}
294 	return 0;
295 }
296 
297 #define DUP_CTX_STR(field)						\
298 do {									\
299 	if (ctx->field) {						\
300 		new_ctx->field = kstrdup(ctx->field, GFP_ATOMIC);	\
301 		if (new_ctx->field == NULL) {				\
302 			smb3_cleanup_fs_context_contents(new_ctx);	\
303 			return -ENOMEM;					\
304 		}							\
305 	}								\
306 } while (0)
307 
308 int
309 smb3_fs_context_dup(struct smb3_fs_context *new_ctx, struct smb3_fs_context *ctx)
310 {
311 	memcpy(new_ctx, ctx, sizeof(*ctx));
312 	new_ctx->prepath = NULL;
313 	new_ctx->nodename = NULL;
314 	new_ctx->username = NULL;
315 	new_ctx->password = NULL;
316 	new_ctx->server_hostname = NULL;
317 	new_ctx->domainname = NULL;
318 	new_ctx->UNC = NULL;
319 	new_ctx->source = NULL;
320 	new_ctx->iocharset = NULL;
321 	new_ctx->leaf_fullpath = NULL;
322 	/*
323 	 * Make sure to stay in sync with smb3_cleanup_fs_context_contents()
324 	 */
325 	DUP_CTX_STR(prepath);
326 	DUP_CTX_STR(username);
327 	DUP_CTX_STR(password);
328 	DUP_CTX_STR(server_hostname);
329 	DUP_CTX_STR(UNC);
330 	DUP_CTX_STR(source);
331 	DUP_CTX_STR(domainname);
332 	DUP_CTX_STR(nodename);
333 	DUP_CTX_STR(iocharset);
334 	DUP_CTX_STR(leaf_fullpath);
335 
336 	return 0;
337 }
338 
339 static int
340 cifs_parse_smb_version(struct fs_context *fc, char *value, struct smb3_fs_context *ctx, bool is_smb3)
341 {
342 	substring_t args[MAX_OPT_ARGS];
343 
344 	switch (match_token(value, cifs_smb_version_tokens, args)) {
345 #ifdef CONFIG_CIFS_ALLOW_INSECURE_LEGACY
346 	case Smb_1:
347 		if (disable_legacy_dialects) {
348 			cifs_errorf(fc, "mount with legacy dialect disabled\n");
349 			return 1;
350 		}
351 		if (is_smb3) {
352 			cifs_errorf(fc, "vers=1.0 (cifs) not permitted when mounting with smb3\n");
353 			return 1;
354 		}
355 		cifs_errorf(fc, "Use of the less secure dialect vers=1.0 is not recommended unless required for access to very old servers\n");
356 		ctx->ops = &smb1_operations;
357 		ctx->vals = &smb1_values;
358 		break;
359 	case Smb_20:
360 		if (disable_legacy_dialects) {
361 			cifs_errorf(fc, "mount with legacy dialect disabled\n");
362 			return 1;
363 		}
364 		if (is_smb3) {
365 			cifs_errorf(fc, "vers=2.0 not permitted when mounting with smb3\n");
366 			return 1;
367 		}
368 		ctx->ops = &smb20_operations;
369 		ctx->vals = &smb20_values;
370 		break;
371 #else
372 	case Smb_1:
373 		cifs_errorf(fc, "vers=1.0 (cifs) mount not permitted when legacy dialects disabled\n");
374 		return 1;
375 	case Smb_20:
376 		cifs_errorf(fc, "vers=2.0 mount not permitted when legacy dialects disabled\n");
377 		return 1;
378 #endif /* CIFS_ALLOW_INSECURE_LEGACY */
379 	case Smb_21:
380 		ctx->ops = &smb21_operations;
381 		ctx->vals = &smb21_values;
382 		break;
383 	case Smb_30:
384 		ctx->ops = &smb30_operations;
385 		ctx->vals = &smb30_values;
386 		break;
387 	case Smb_302:
388 		ctx->ops = &smb30_operations; /* currently identical with 3.0 */
389 		ctx->vals = &smb302_values;
390 		break;
391 	case Smb_311:
392 		ctx->ops = &smb311_operations;
393 		ctx->vals = &smb311_values;
394 		break;
395 	case Smb_3any:
396 		ctx->ops = &smb30_operations; /* currently identical with 3.0 */
397 		ctx->vals = &smb3any_values;
398 		break;
399 	case Smb_default:
400 		ctx->ops = &smb30_operations;
401 		ctx->vals = &smbdefault_values;
402 		break;
403 	default:
404 		cifs_errorf(fc, "Unknown vers= option specified: %s\n", value);
405 		return 1;
406 	}
407 	return 0;
408 }
409 
410 int smb3_parse_opt(const char *options, const char *key, char **val)
411 {
412 	int rc = -ENOENT;
413 	char *opts, *orig, *p;
414 
415 	orig = opts = kstrdup(options, GFP_KERNEL);
416 	if (!opts)
417 		return -ENOMEM;
418 
419 	while ((p = strsep(&opts, ","))) {
420 		char *nval;
421 
422 		if (!*p)
423 			continue;
424 		if (strncasecmp(p, key, strlen(key)))
425 			continue;
426 		nval = strchr(p, '=');
427 		if (nval) {
428 			if (nval == p)
429 				continue;
430 			*nval++ = 0;
431 			*val = kstrdup(nval, GFP_KERNEL);
432 			rc = !*val ? -ENOMEM : 0;
433 			goto out;
434 		}
435 	}
436 out:
437 	kfree(orig);
438 	return rc;
439 }
440 
441 /*
442  * Remove duplicate path delimiters. Windows is supposed to do that
443  * but there are some bugs that prevent rename from working if there are
444  * multiple delimiters.
445  *
446  * Return a sanitized duplicate of @path or NULL for empty prefix paths.
447  * Otherwise, return ERR_PTR.
448  *
449  * @gfp indicates the GFP_* flags for kstrdup.
450  * The caller is responsible for freeing the original.
451  */
452 #define IS_DELIM(c) ((c) == '/' || (c) == '\\')
453 char *cifs_sanitize_prepath(char *prepath, gfp_t gfp)
454 {
455 	char *cursor1 = prepath, *cursor2 = prepath;
456 	char *s;
457 
458 	/* skip all prepended delimiters */
459 	while (IS_DELIM(*cursor1))
460 		cursor1++;
461 
462 	/* copy the first letter */
463 	*cursor2 = *cursor1;
464 
465 	/* copy the remainder... */
466 	while (*(cursor1++)) {
467 		/* ... skipping all duplicated delimiters */
468 		if (IS_DELIM(*cursor1) && IS_DELIM(*cursor2))
469 			continue;
470 		*(++cursor2) = *cursor1;
471 	}
472 
473 	/* if the last character is a delimiter, skip it */
474 	if (IS_DELIM(*(cursor2 - 1)))
475 		cursor2--;
476 
477 	*cursor2 = '\0';
478 	if (!*prepath)
479 		return NULL;
480 	s = kstrdup(prepath, gfp);
481 	if (!s)
482 		return ERR_PTR(-ENOMEM);
483 	return s;
484 }
485 
486 /*
487  * Return full path based on the values of @ctx->{UNC,prepath}.
488  *
489  * It is assumed that both values were already parsed by smb3_parse_devname().
490  */
491 char *smb3_fs_context_fullpath(const struct smb3_fs_context *ctx, char dirsep)
492 {
493 	size_t ulen, plen;
494 	char *s;
495 
496 	ulen = strlen(ctx->UNC);
497 	plen = ctx->prepath ? strlen(ctx->prepath) + 1 : 0;
498 
499 	s = kmalloc(ulen + plen + 1, GFP_KERNEL);
500 	if (!s)
501 		return ERR_PTR(-ENOMEM);
502 	memcpy(s, ctx->UNC, ulen);
503 	if (plen) {
504 		s[ulen] = dirsep;
505 		memcpy(s + ulen + 1, ctx->prepath, plen);
506 	}
507 	s[ulen + plen] = '\0';
508 	convert_delimiter(s, dirsep);
509 	return s;
510 }
511 
512 /*
513  * Parse a devname into substrings and populate the ctx->UNC and ctx->prepath
514  * fields with the result. Returns 0 on success and an error otherwise
515  * (e.g. ENOMEM or EINVAL)
516  */
517 int
518 smb3_parse_devname(const char *devname, struct smb3_fs_context *ctx)
519 {
520 	char *pos;
521 	const char *delims = "/\\";
522 	size_t len;
523 	int rc;
524 
525 	if (unlikely(!devname || !*devname)) {
526 		cifs_dbg(VFS, "Device name not specified\n");
527 		return -EINVAL;
528 	}
529 
530 	/* make sure we have a valid UNC double delimiter prefix */
531 	len = strspn(devname, delims);
532 	if (len != 2)
533 		return -EINVAL;
534 
535 	/* find delimiter between host and sharename */
536 	pos = strpbrk(devname + 2, delims);
537 	if (!pos)
538 		return -EINVAL;
539 
540 	/* record the server hostname */
541 	kfree(ctx->server_hostname);
542 	ctx->server_hostname = kstrndup(devname + 2, pos - devname - 2, GFP_KERNEL);
543 	if (!ctx->server_hostname)
544 		return -ENOMEM;
545 
546 	/* skip past delimiter */
547 	++pos;
548 
549 	/* now go until next delimiter or end of string */
550 	len = strcspn(pos, delims);
551 	if (!len)
552 		return -EINVAL;
553 
554 	/* move "pos" up to delimiter or NULL */
555 	pos += len;
556 	kfree(ctx->UNC);
557 	ctx->UNC = kstrndup(devname, pos - devname, GFP_KERNEL);
558 	if (!ctx->UNC)
559 		return -ENOMEM;
560 
561 	convert_delimiter(ctx->UNC, '\\');
562 
563 	/* skip any delimiter */
564 	if (*pos == '/' || *pos == '\\')
565 		pos++;
566 
567 	kfree(ctx->prepath);
568 	ctx->prepath = NULL;
569 
570 	/* If pos is NULL then no prepath */
571 	if (!*pos)
572 		return 0;
573 
574 	ctx->prepath = cifs_sanitize_prepath(pos, GFP_KERNEL);
575 	if (IS_ERR(ctx->prepath)) {
576 		rc = PTR_ERR(ctx->prepath);
577 		ctx->prepath = NULL;
578 		return rc;
579 	}
580 
581 	return 0;
582 }
583 
584 static void smb3_fs_context_free(struct fs_context *fc);
585 static int smb3_fs_context_parse_param(struct fs_context *fc,
586 				       struct fs_parameter *param);
587 static int smb3_fs_context_parse_monolithic(struct fs_context *fc,
588 					    void *data);
589 static int smb3_get_tree(struct fs_context *fc);
590 static int smb3_reconfigure(struct fs_context *fc);
591 
592 static const struct fs_context_operations smb3_fs_context_ops = {
593 	.free			= smb3_fs_context_free,
594 	.parse_param		= smb3_fs_context_parse_param,
595 	.parse_monolithic	= smb3_fs_context_parse_monolithic,
596 	.get_tree		= smb3_get_tree,
597 	.reconfigure		= smb3_reconfigure,
598 };
599 
600 /*
601  * Parse a monolithic block of data from sys_mount().
602  * smb3_fs_context_parse_monolithic - Parse key[=val][,key[=val]]* mount data
603  * @ctx: The superblock configuration to fill in.
604  * @data: The data to parse
605  *
606  * Parse a blob of data that's in key[=val][,key[=val]]* form.  This can be
607  * called from the ->monolithic_mount_data() fs_context operation.
608  *
609  * Returns 0 on success or the error returned by the ->parse_option() fs_context
610  * operation on failure.
611  */
612 static int smb3_fs_context_parse_monolithic(struct fs_context *fc,
613 					   void *data)
614 {
615 	char *options = data, *key;
616 	int ret = 0;
617 
618 	if (!options)
619 		return 0;
620 
621 	ret = security_sb_eat_lsm_opts(options, &fc->security);
622 	if (ret)
623 		return ret;
624 
625 	/* BB Need to add support for sep= here TBD */
626 	while ((key = strsep(&options, ",")) != NULL) {
627 		size_t len;
628 		char *value;
629 
630 		if (*key == 0)
631 			break;
632 
633 		/* Check if following character is the deliminator If yes,
634 		 * we have encountered a double deliminator reset the NULL
635 		 * character to the deliminator
636 		 */
637 		while (options && options[0] == ',') {
638 			len = strlen(key);
639 			strcpy(key + len, options);
640 			options = strchr(options, ',');
641 			if (options)
642 				*options++ = 0;
643 		}
644 
645 
646 		len = 0;
647 		value = strchr(key, '=');
648 		if (value) {
649 			if (value == key)
650 				continue;
651 			*value++ = 0;
652 			len = strlen(value);
653 		}
654 
655 		ret = vfs_parse_fs_string(fc, key, value, len);
656 		if (ret < 0)
657 			break;
658 	}
659 
660 	return ret;
661 }
662 
663 /*
664  * Validate the preparsed information in the config.
665  */
666 static int smb3_fs_context_validate(struct fs_context *fc)
667 {
668 	struct smb3_fs_context *ctx = smb3_fc2context(fc);
669 
670 	if (ctx->rdma && ctx->vals->protocol_id < SMB30_PROT_ID) {
671 		cifs_errorf(fc, "SMB Direct requires Version >=3.0\n");
672 		return -EOPNOTSUPP;
673 	}
674 
675 #ifndef CONFIG_KEYS
676 	/* Muliuser mounts require CONFIG_KEYS support */
677 	if (ctx->multiuser) {
678 		cifs_errorf(fc, "Multiuser mounts require kernels with CONFIG_KEYS enabled\n");
679 		return -1;
680 	}
681 #endif
682 
683 	if (ctx->got_version == false)
684 		pr_warn_once("No dialect specified on mount. Default has changed to a more secure dialect, SMB2.1 or later (e.g. SMB3.1.1), from CIFS (SMB1). To use the less secure SMB1 dialect to access old servers which do not support SMB3.1.1 (or even SMB3 or SMB2.1) specify vers=1.0 on mount.\n");
685 
686 
687 	if (!ctx->UNC) {
688 		cifs_errorf(fc, "CIFS mount error: No usable UNC path provided in device string!\n");
689 		return -1;
690 	}
691 
692 	/* make sure UNC has a share name */
693 	if (strlen(ctx->UNC) < 3 || !strchr(ctx->UNC + 3, '\\')) {
694 		cifs_errorf(fc, "Malformed UNC. Unable to find share name.\n");
695 		return -ENOENT;
696 	}
697 
698 	if (!ctx->got_ip) {
699 		int len;
700 		const char *slash;
701 
702 		/* No ip= option specified? Try to get it from UNC */
703 		/* Use the address part of the UNC. */
704 		slash = strchr(&ctx->UNC[2], '\\');
705 		len = slash - &ctx->UNC[2];
706 		if (!cifs_convert_address((struct sockaddr *)&ctx->dstaddr,
707 					  &ctx->UNC[2], len)) {
708 			pr_err("Unable to determine destination address\n");
709 			return -EHOSTUNREACH;
710 		}
711 	}
712 
713 	/* set the port that we got earlier */
714 	cifs_set_port((struct sockaddr *)&ctx->dstaddr, ctx->port);
715 
716 	if (ctx->override_uid && !ctx->uid_specified) {
717 		ctx->override_uid = 0;
718 		pr_notice("ignoring forceuid mount option specified with no uid= option\n");
719 	}
720 
721 	if (ctx->override_gid && !ctx->gid_specified) {
722 		ctx->override_gid = 0;
723 		pr_notice("ignoring forcegid mount option specified with no gid= option\n");
724 	}
725 
726 	return 0;
727 }
728 
729 static int smb3_get_tree_common(struct fs_context *fc)
730 {
731 	struct smb3_fs_context *ctx = smb3_fc2context(fc);
732 	struct dentry *root;
733 	int rc = 0;
734 
735 	root = cifs_smb3_do_mount(fc->fs_type, 0, ctx);
736 	if (IS_ERR(root))
737 		return PTR_ERR(root);
738 
739 	fc->root = root;
740 
741 	return rc;
742 }
743 
744 /*
745  * Create an SMB3 superblock from the parameters passed.
746  */
747 static int smb3_get_tree(struct fs_context *fc)
748 {
749 	int err = smb3_fs_context_validate(fc);
750 	int ret;
751 
752 	if (err)
753 		return err;
754 	mutex_lock(&cifs_mount_mutex);
755 	ret = smb3_get_tree_common(fc);
756 	mutex_unlock(&cifs_mount_mutex);
757 	return ret;
758 }
759 
760 static void smb3_fs_context_free(struct fs_context *fc)
761 {
762 	struct smb3_fs_context *ctx = smb3_fc2context(fc);
763 
764 	smb3_cleanup_fs_context(ctx);
765 }
766 
767 /*
768  * Compare the old and new proposed context during reconfigure
769  * and check if the changes are compatible.
770  */
771 static int smb3_verify_reconfigure_ctx(struct fs_context *fc,
772 				       struct smb3_fs_context *new_ctx,
773 				       struct smb3_fs_context *old_ctx)
774 {
775 	if (new_ctx->posix_paths != old_ctx->posix_paths) {
776 		cifs_errorf(fc, "can not change posixpaths during remount\n");
777 		return -EINVAL;
778 	}
779 	if (new_ctx->sectype != old_ctx->sectype) {
780 		cifs_errorf(fc, "can not change sec during remount\n");
781 		return -EINVAL;
782 	}
783 	if (new_ctx->multiuser != old_ctx->multiuser) {
784 		cifs_errorf(fc, "can not change multiuser during remount\n");
785 		return -EINVAL;
786 	}
787 	if (new_ctx->UNC &&
788 	    (!old_ctx->UNC || strcmp(new_ctx->UNC, old_ctx->UNC))) {
789 		cifs_errorf(fc, "can not change UNC during remount\n");
790 		return -EINVAL;
791 	}
792 	if (new_ctx->username &&
793 	    (!old_ctx->username || strcmp(new_ctx->username, old_ctx->username))) {
794 		cifs_errorf(fc, "can not change username during remount\n");
795 		return -EINVAL;
796 	}
797 	if (new_ctx->password &&
798 	    (!old_ctx->password || strcmp(new_ctx->password, old_ctx->password))) {
799 		cifs_errorf(fc, "can not change password during remount\n");
800 		return -EINVAL;
801 	}
802 	if (new_ctx->domainname &&
803 	    (!old_ctx->domainname || strcmp(new_ctx->domainname, old_ctx->domainname))) {
804 		cifs_errorf(fc, "can not change domainname during remount\n");
805 		return -EINVAL;
806 	}
807 	if (strcmp(new_ctx->workstation_name, old_ctx->workstation_name)) {
808 		cifs_errorf(fc, "can not change workstation_name during remount\n");
809 		return -EINVAL;
810 	}
811 	if (new_ctx->nodename &&
812 	    (!old_ctx->nodename || strcmp(new_ctx->nodename, old_ctx->nodename))) {
813 		cifs_errorf(fc, "can not change nodename during remount\n");
814 		return -EINVAL;
815 	}
816 	if (new_ctx->iocharset &&
817 	    (!old_ctx->iocharset || strcmp(new_ctx->iocharset, old_ctx->iocharset))) {
818 		cifs_errorf(fc, "can not change iocharset during remount\n");
819 		return -EINVAL;
820 	}
821 
822 	return 0;
823 }
824 
825 #define STEAL_STRING(cifs_sb, ctx, field)				\
826 do {									\
827 	kfree(ctx->field);						\
828 	ctx->field = cifs_sb->ctx->field;				\
829 	cifs_sb->ctx->field = NULL;					\
830 } while (0)
831 
832 #define STEAL_STRING_SENSITIVE(cifs_sb, ctx, field)			\
833 do {									\
834 	kfree_sensitive(ctx->field);					\
835 	ctx->field = cifs_sb->ctx->field;				\
836 	cifs_sb->ctx->field = NULL;					\
837 } while (0)
838 
839 static int smb3_reconfigure(struct fs_context *fc)
840 {
841 	struct smb3_fs_context *ctx = smb3_fc2context(fc);
842 	struct dentry *root = fc->root;
843 	struct cifs_sb_info *cifs_sb = CIFS_SB(root->d_sb);
844 	int rc;
845 
846 	rc = smb3_verify_reconfigure_ctx(fc, ctx, cifs_sb->ctx);
847 	if (rc)
848 		return rc;
849 
850 	/*
851 	 * We can not change UNC/username/password/domainname/
852 	 * workstation_name/nodename/iocharset
853 	 * during reconnect so ignore what we have in the new context and
854 	 * just use what we already have in cifs_sb->ctx.
855 	 */
856 	STEAL_STRING(cifs_sb, ctx, UNC);
857 	STEAL_STRING(cifs_sb, ctx, source);
858 	STEAL_STRING(cifs_sb, ctx, username);
859 	STEAL_STRING_SENSITIVE(cifs_sb, ctx, password);
860 	STEAL_STRING(cifs_sb, ctx, domainname);
861 	STEAL_STRING(cifs_sb, ctx, nodename);
862 	STEAL_STRING(cifs_sb, ctx, iocharset);
863 
864 	/* if rsize or wsize not passed in on remount, use previous values */
865 	if (ctx->rsize == 0)
866 		ctx->rsize = cifs_sb->ctx->rsize;
867 	if (ctx->wsize == 0)
868 		ctx->wsize = cifs_sb->ctx->wsize;
869 
870 
871 	smb3_cleanup_fs_context_contents(cifs_sb->ctx);
872 	rc = smb3_fs_context_dup(cifs_sb->ctx, ctx);
873 	smb3_update_mnt_flags(cifs_sb);
874 #ifdef CONFIG_CIFS_DFS_UPCALL
875 	if (!rc)
876 		rc = dfs_cache_remount_fs(cifs_sb);
877 #endif
878 
879 	return rc;
880 }
881 
882 static int smb3_fs_context_parse_param(struct fs_context *fc,
883 				      struct fs_parameter *param)
884 {
885 	struct fs_parse_result result;
886 	struct smb3_fs_context *ctx = smb3_fc2context(fc);
887 	int i, opt;
888 	bool is_smb3 = !strcmp(fc->fs_type->name, "smb3");
889 	bool skip_parsing = false;
890 	kuid_t uid;
891 	kgid_t gid;
892 
893 	cifs_dbg(FYI, "CIFS: parsing cifs mount option '%s'\n", param->key);
894 
895 	/*
896 	 * fs_parse can not handle string options with an empty value so
897 	 * we will need special handling of them.
898 	 */
899 	if (param->type == fs_value_is_string && param->string[0] == 0) {
900 		if (!strcmp("pass", param->key) || !strcmp("password", param->key)) {
901 			skip_parsing = true;
902 			opt = Opt_pass;
903 		} else if (!strcmp("user", param->key) || !strcmp("username", param->key)) {
904 			skip_parsing = true;
905 			opt = Opt_user;
906 		}
907 	}
908 
909 	if (!skip_parsing) {
910 		opt = fs_parse(fc, smb3_fs_parameters, param, &result);
911 		if (opt < 0)
912 			return ctx->sloppy ? 1 : opt;
913 	}
914 
915 	switch (opt) {
916 	case Opt_compress:
917 		ctx->compression = UNKNOWN_TYPE;
918 		cifs_dbg(VFS,
919 			"SMB3 compression support is experimental\n");
920 		break;
921 	case Opt_nodfs:
922 		ctx->nodfs = 1;
923 		break;
924 	case Opt_hard:
925 		if (result.negated) {
926 			if (ctx->retry == 1)
927 				cifs_dbg(VFS, "conflicting hard vs. soft mount options\n");
928 			ctx->retry = 0;
929 		} else
930 			ctx->retry = 1;
931 		break;
932 	case Opt_soft:
933 		if (result.negated)
934 			ctx->retry = 1;
935 		else {
936 			if (ctx->retry == 1)
937 				cifs_dbg(VFS, "conflicting hard vs soft mount options\n");
938 			ctx->retry = 0;
939 		}
940 		break;
941 	case Opt_mapposix:
942 		if (result.negated)
943 			ctx->remap = false;
944 		else {
945 			ctx->remap = true;
946 			ctx->sfu_remap = false; /* disable SFU mapping */
947 		}
948 		break;
949 	case Opt_mapchars:
950 		if (result.negated)
951 			ctx->sfu_remap = false;
952 		else {
953 			ctx->sfu_remap = true;
954 			ctx->remap = false; /* disable SFM (mapposix) mapping */
955 		}
956 		break;
957 	case Opt_user_xattr:
958 		if (result.negated)
959 			ctx->no_xattr = 1;
960 		else
961 			ctx->no_xattr = 0;
962 		break;
963 	case Opt_forceuid:
964 		if (result.negated)
965 			ctx->override_uid = 0;
966 		else
967 			ctx->override_uid = 1;
968 		break;
969 	case Opt_forcegid:
970 		if (result.negated)
971 			ctx->override_gid = 0;
972 		else
973 			ctx->override_gid = 1;
974 		break;
975 	case Opt_perm:
976 		if (result.negated)
977 			ctx->noperm = 1;
978 		else
979 			ctx->noperm = 0;
980 		break;
981 	case Opt_dynperm:
982 		if (result.negated)
983 			ctx->dynperm = 0;
984 		else
985 			ctx->dynperm = 1;
986 		break;
987 	case Opt_sfu:
988 		if (result.negated)
989 			ctx->sfu_emul = 0;
990 		else
991 			ctx->sfu_emul = 1;
992 		break;
993 	case Opt_noblocksend:
994 		ctx->noblocksnd = 1;
995 		break;
996 	case Opt_noautotune:
997 		ctx->noautotune = 1;
998 		break;
999 	case Opt_nolease:
1000 		ctx->no_lease = 1;
1001 		break;
1002 	case Opt_nosparse:
1003 		ctx->no_sparse = 1;
1004 		break;
1005 	case Opt_nodelete:
1006 		ctx->nodelete = 1;
1007 		break;
1008 	case Opt_multichannel:
1009 		if (result.negated) {
1010 			ctx->multichannel = false;
1011 			ctx->max_channels = 1;
1012 		} else {
1013 			ctx->multichannel = true;
1014 			/* if number of channels not specified, default to 2 */
1015 			if (ctx->max_channels < 2)
1016 				ctx->max_channels = 2;
1017 		}
1018 		break;
1019 	case Opt_uid:
1020 		uid = make_kuid(current_user_ns(), result.uint_32);
1021 		if (!uid_valid(uid))
1022 			goto cifs_parse_mount_err;
1023 		ctx->linux_uid = uid;
1024 		ctx->uid_specified = true;
1025 		break;
1026 	case Opt_cruid:
1027 		uid = make_kuid(current_user_ns(), result.uint_32);
1028 		if (!uid_valid(uid))
1029 			goto cifs_parse_mount_err;
1030 		ctx->cred_uid = uid;
1031 		ctx->cruid_specified = true;
1032 		break;
1033 	case Opt_backupuid:
1034 		uid = make_kuid(current_user_ns(), result.uint_32);
1035 		if (!uid_valid(uid))
1036 			goto cifs_parse_mount_err;
1037 		ctx->backupuid = uid;
1038 		ctx->backupuid_specified = true;
1039 		break;
1040 	case Opt_backupgid:
1041 		gid = make_kgid(current_user_ns(), result.uint_32);
1042 		if (!gid_valid(gid))
1043 			goto cifs_parse_mount_err;
1044 		ctx->backupgid = gid;
1045 		ctx->backupgid_specified = true;
1046 		break;
1047 	case Opt_gid:
1048 		gid = make_kgid(current_user_ns(), result.uint_32);
1049 		if (!gid_valid(gid))
1050 			goto cifs_parse_mount_err;
1051 		ctx->linux_gid = gid;
1052 		ctx->gid_specified = true;
1053 		break;
1054 	case Opt_port:
1055 		ctx->port = result.uint_32;
1056 		break;
1057 	case Opt_file_mode:
1058 		ctx->file_mode = result.uint_32;
1059 		break;
1060 	case Opt_dirmode:
1061 		ctx->dir_mode = result.uint_32;
1062 		break;
1063 	case Opt_min_enc_offload:
1064 		ctx->min_offload = result.uint_32;
1065 		break;
1066 	case Opt_blocksize:
1067 		/*
1068 		 * inode blocksize realistically should never need to be
1069 		 * less than 16K or greater than 16M and default is 1MB.
1070 		 * Note that small inode block sizes (e.g. 64K) can lead
1071 		 * to very poor performance of common tools like cp and scp
1072 		 */
1073 		if ((result.uint_32 < CIFS_MAX_MSGSIZE) ||
1074 		   (result.uint_32 > (4 * SMB3_DEFAULT_IOSIZE))) {
1075 			cifs_errorf(fc, "%s: Invalid blocksize\n",
1076 				__func__);
1077 			goto cifs_parse_mount_err;
1078 		}
1079 		ctx->bsize = result.uint_32;
1080 		ctx->got_bsize = true;
1081 		break;
1082 	case Opt_rasize:
1083 		/*
1084 		 * readahead size realistically should never need to be
1085 		 * less than 1M (CIFS_DEFAULT_IOSIZE) or greater than 32M
1086 		 * (perhaps an exception should be considered in the
1087 		 * for the case of a large number of channels
1088 		 * when multichannel is negotiated) since that would lead
1089 		 * to plenty of parallel I/O in flight to the server.
1090 		 * Note that smaller read ahead sizes would
1091 		 * hurt performance of common tools like cp and scp
1092 		 * which often trigger sequential i/o with read ahead
1093 		 */
1094 		if ((result.uint_32 > (8 * SMB3_DEFAULT_IOSIZE)) ||
1095 		    (result.uint_32 < CIFS_DEFAULT_IOSIZE)) {
1096 			cifs_errorf(fc, "%s: Invalid rasize %d vs. %d\n",
1097 				__func__, result.uint_32, SMB3_DEFAULT_IOSIZE);
1098 			goto cifs_parse_mount_err;
1099 		}
1100 		ctx->rasize = result.uint_32;
1101 		break;
1102 	case Opt_rsize:
1103 		ctx->rsize = result.uint_32;
1104 		ctx->got_rsize = true;
1105 		break;
1106 	case Opt_wsize:
1107 		ctx->wsize = result.uint_32;
1108 		ctx->got_wsize = true;
1109 		break;
1110 	case Opt_acregmax:
1111 		ctx->acregmax = HZ * result.uint_32;
1112 		if (ctx->acregmax > CIFS_MAX_ACTIMEO) {
1113 			cifs_errorf(fc, "acregmax too large\n");
1114 			goto cifs_parse_mount_err;
1115 		}
1116 		break;
1117 	case Opt_acdirmax:
1118 		ctx->acdirmax = HZ * result.uint_32;
1119 		if (ctx->acdirmax > CIFS_MAX_ACTIMEO) {
1120 			cifs_errorf(fc, "acdirmax too large\n");
1121 			goto cifs_parse_mount_err;
1122 		}
1123 		break;
1124 	case Opt_actimeo:
1125 		if (HZ * result.uint_32 > CIFS_MAX_ACTIMEO) {
1126 			cifs_errorf(fc, "timeout too large\n");
1127 			goto cifs_parse_mount_err;
1128 		}
1129 		if ((ctx->acdirmax != CIFS_DEF_ACTIMEO) ||
1130 		    (ctx->acregmax != CIFS_DEF_ACTIMEO)) {
1131 			cifs_errorf(fc, "actimeo ignored since acregmax or acdirmax specified\n");
1132 			break;
1133 		}
1134 		ctx->acdirmax = ctx->acregmax = HZ * result.uint_32;
1135 		break;
1136 	case Opt_closetimeo:
1137 		ctx->closetimeo = HZ * result.uint_32;
1138 		if (ctx->closetimeo > SMB3_MAX_DCLOSETIMEO) {
1139 			cifs_errorf(fc, "closetimeo too large\n");
1140 			goto cifs_parse_mount_err;
1141 		}
1142 		break;
1143 	case Opt_echo_interval:
1144 		ctx->echo_interval = result.uint_32;
1145 		break;
1146 	case Opt_snapshot:
1147 		ctx->snapshot_time = result.uint_64;
1148 		break;
1149 	case Opt_max_credits:
1150 		if (result.uint_32 < 20 || result.uint_32 > 60000) {
1151 			cifs_errorf(fc, "%s: Invalid max_credits value\n",
1152 				 __func__);
1153 			goto cifs_parse_mount_err;
1154 		}
1155 		ctx->max_credits = result.uint_32;
1156 		break;
1157 	case Opt_max_channels:
1158 		if (result.uint_32 < 1 || result.uint_32 > CIFS_MAX_CHANNELS) {
1159 			cifs_errorf(fc, "%s: Invalid max_channels value, needs to be 1-%d\n",
1160 				 __func__, CIFS_MAX_CHANNELS);
1161 			goto cifs_parse_mount_err;
1162 		}
1163 		ctx->max_channels = result.uint_32;
1164 		/* If more than one channel requested ... they want multichan */
1165 		if (result.uint_32 > 1)
1166 			ctx->multichannel = true;
1167 		break;
1168 	case Opt_handletimeout:
1169 		ctx->handle_timeout = result.uint_32;
1170 		if (ctx->handle_timeout > SMB3_MAX_HANDLE_TIMEOUT) {
1171 			cifs_errorf(fc, "Invalid handle cache timeout, longer than 16 minutes\n");
1172 			goto cifs_parse_mount_err;
1173 		}
1174 		break;
1175 	case Opt_source:
1176 		kfree(ctx->UNC);
1177 		ctx->UNC = NULL;
1178 		switch (smb3_parse_devname(param->string, ctx)) {
1179 		case 0:
1180 			break;
1181 		case -ENOMEM:
1182 			cifs_errorf(fc, "Unable to allocate memory for devname\n");
1183 			goto cifs_parse_mount_err;
1184 		case -EINVAL:
1185 			cifs_errorf(fc, "Malformed UNC in devname\n");
1186 			goto cifs_parse_mount_err;
1187 		default:
1188 			cifs_errorf(fc, "Unknown error parsing devname\n");
1189 			goto cifs_parse_mount_err;
1190 		}
1191 		ctx->source = smb3_fs_context_fullpath(ctx, '/');
1192 		if (IS_ERR(ctx->source)) {
1193 			ctx->source = NULL;
1194 			cifs_errorf(fc, "OOM when copying UNC string\n");
1195 			goto cifs_parse_mount_err;
1196 		}
1197 		fc->source = kstrdup(ctx->source, GFP_KERNEL);
1198 		if (fc->source == NULL) {
1199 			cifs_errorf(fc, "OOM when copying UNC string\n");
1200 			goto cifs_parse_mount_err;
1201 		}
1202 		break;
1203 	case Opt_user:
1204 		kfree(ctx->username);
1205 		ctx->username = NULL;
1206 		if (ctx->nullauth)
1207 			break;
1208 		if (strlen(param->string) == 0) {
1209 			/* null user, ie. anonymous authentication */
1210 			ctx->nullauth = 1;
1211 			break;
1212 		}
1213 
1214 		if (strnlen(param->string, CIFS_MAX_USERNAME_LEN) >
1215 		    CIFS_MAX_USERNAME_LEN) {
1216 			pr_warn("username too long\n");
1217 			goto cifs_parse_mount_err;
1218 		}
1219 		ctx->username = kstrdup(param->string, GFP_KERNEL);
1220 		if (ctx->username == NULL) {
1221 			cifs_errorf(fc, "OOM when copying username string\n");
1222 			goto cifs_parse_mount_err;
1223 		}
1224 		break;
1225 	case Opt_pass:
1226 		kfree_sensitive(ctx->password);
1227 		ctx->password = NULL;
1228 		if (strlen(param->string) == 0)
1229 			break;
1230 
1231 		ctx->password = kstrdup(param->string, GFP_KERNEL);
1232 		if (ctx->password == NULL) {
1233 			cifs_errorf(fc, "OOM when copying password string\n");
1234 			goto cifs_parse_mount_err;
1235 		}
1236 		break;
1237 	case Opt_ip:
1238 		if (strlen(param->string) == 0) {
1239 			ctx->got_ip = false;
1240 			break;
1241 		}
1242 		if (!cifs_convert_address((struct sockaddr *)&ctx->dstaddr,
1243 					  param->string,
1244 					  strlen(param->string))) {
1245 			pr_err("bad ip= option (%s)\n", param->string);
1246 			goto cifs_parse_mount_err;
1247 		}
1248 		ctx->got_ip = true;
1249 		break;
1250 	case Opt_domain:
1251 		if (strnlen(param->string, CIFS_MAX_DOMAINNAME_LEN)
1252 				== CIFS_MAX_DOMAINNAME_LEN) {
1253 			pr_warn("domain name too long\n");
1254 			goto cifs_parse_mount_err;
1255 		}
1256 
1257 		kfree(ctx->domainname);
1258 		ctx->domainname = kstrdup(param->string, GFP_KERNEL);
1259 		if (ctx->domainname == NULL) {
1260 			cifs_errorf(fc, "OOM when copying domainname string\n");
1261 			goto cifs_parse_mount_err;
1262 		}
1263 		cifs_dbg(FYI, "Domain name set\n");
1264 		break;
1265 	case Opt_srcaddr:
1266 		if (!cifs_convert_address(
1267 				(struct sockaddr *)&ctx->srcaddr,
1268 				param->string, strlen(param->string))) {
1269 			pr_warn("Could not parse srcaddr: %s\n",
1270 				param->string);
1271 			goto cifs_parse_mount_err;
1272 		}
1273 		break;
1274 	case Opt_iocharset:
1275 		if (strnlen(param->string, 1024) >= 65) {
1276 			pr_warn("iocharset name too long\n");
1277 			goto cifs_parse_mount_err;
1278 		}
1279 
1280 		if (strncasecmp(param->string, "default", 7) != 0) {
1281 			kfree(ctx->iocharset);
1282 			ctx->iocharset = kstrdup(param->string, GFP_KERNEL);
1283 			if (ctx->iocharset == NULL) {
1284 				cifs_errorf(fc, "OOM when copying iocharset string\n");
1285 				goto cifs_parse_mount_err;
1286 			}
1287 		}
1288 		/* if iocharset not set then load_nls_default
1289 		 * is used by caller
1290 		 */
1291 		cifs_dbg(FYI, "iocharset set to %s\n", ctx->iocharset);
1292 		break;
1293 	case Opt_netbiosname:
1294 		memset(ctx->source_rfc1001_name, 0x20,
1295 			RFC1001_NAME_LEN);
1296 		/*
1297 		 * FIXME: are there cases in which a comma can
1298 		 * be valid in workstation netbios name (and
1299 		 * need special handling)?
1300 		 */
1301 		for (i = 0; i < RFC1001_NAME_LEN; i++) {
1302 			/* don't ucase netbiosname for user */
1303 			if (param->string[i] == 0)
1304 				break;
1305 			ctx->source_rfc1001_name[i] = param->string[i];
1306 		}
1307 		/* The string has 16th byte zero still from
1308 		 * set at top of the function
1309 		 */
1310 		if (i == RFC1001_NAME_LEN && param->string[i] != 0)
1311 			pr_warn("netbiosname longer than 15 truncated\n");
1312 		break;
1313 	case Opt_servern:
1314 		/* last byte, type, is 0x20 for servr type */
1315 		memset(ctx->target_rfc1001_name, 0x20,
1316 			RFC1001_NAME_LEN_WITH_NULL);
1317 		/*
1318 		 * BB are there cases in which a comma can be valid in this
1319 		 * workstation netbios name (and need special handling)?
1320 		 */
1321 
1322 		/* user or mount helper must uppercase the netbios name */
1323 		for (i = 0; i < 15; i++) {
1324 			if (param->string[i] == 0)
1325 				break;
1326 			ctx->target_rfc1001_name[i] = param->string[i];
1327 		}
1328 
1329 		/* The string has 16th byte zero still from set at top of function */
1330 		if (i == RFC1001_NAME_LEN && param->string[i] != 0)
1331 			pr_warn("server netbiosname longer than 15 truncated\n");
1332 		break;
1333 	case Opt_ver:
1334 		/* version of mount userspace tools, not dialect */
1335 		/* If interface changes in mount.cifs bump to new ver */
1336 		if (strncasecmp(param->string, "1", 1) == 0) {
1337 			if (strlen(param->string) > 1) {
1338 				pr_warn("Bad mount helper ver=%s. Did you want SMB1 (CIFS) dialect and mean to type vers=1.0 instead?\n",
1339 					param->string);
1340 				goto cifs_parse_mount_err;
1341 			}
1342 			/* This is the default */
1343 			break;
1344 		}
1345 		/* For all other value, error */
1346 		pr_warn("Invalid mount helper version specified\n");
1347 		goto cifs_parse_mount_err;
1348 	case Opt_vers:
1349 		/* protocol version (dialect) */
1350 		if (cifs_parse_smb_version(fc, param->string, ctx, is_smb3) != 0)
1351 			goto cifs_parse_mount_err;
1352 		ctx->got_version = true;
1353 		break;
1354 	case Opt_sec:
1355 		if (cifs_parse_security_flavors(fc, param->string, ctx) != 0)
1356 			goto cifs_parse_mount_err;
1357 		break;
1358 	case Opt_cache:
1359 		if (cifs_parse_cache_flavor(fc, param->string, ctx) != 0)
1360 			goto cifs_parse_mount_err;
1361 		break;
1362 	case Opt_witness:
1363 #ifndef CONFIG_CIFS_SWN_UPCALL
1364 		cifs_errorf(fc, "Witness support needs CONFIG_CIFS_SWN_UPCALL config option\n");
1365 			goto cifs_parse_mount_err;
1366 #endif
1367 		ctx->witness = true;
1368 		pr_warn_once("Witness protocol support is experimental\n");
1369 		break;
1370 	case Opt_rootfs:
1371 #ifndef CONFIG_CIFS_ROOT
1372 		cifs_dbg(VFS, "rootfs support requires CONFIG_CIFS_ROOT config option\n");
1373 		goto cifs_parse_mount_err;
1374 #endif
1375 		ctx->rootfs = true;
1376 		break;
1377 	case Opt_posixpaths:
1378 		if (result.negated)
1379 			ctx->posix_paths = 0;
1380 		else
1381 			ctx->posix_paths = 1;
1382 		break;
1383 	case Opt_unix:
1384 		if (result.negated) {
1385 			if (ctx->linux_ext == 1)
1386 				pr_warn_once("conflicting posix mount options specified\n");
1387 			ctx->linux_ext = 0;
1388 			ctx->no_linux_ext = 1;
1389 		} else {
1390 			if (ctx->no_linux_ext == 1)
1391 				pr_warn_once("conflicting posix mount options specified\n");
1392 			ctx->linux_ext = 1;
1393 			ctx->no_linux_ext = 0;
1394 		}
1395 		break;
1396 	case Opt_nocase:
1397 		ctx->nocase = 1;
1398 		break;
1399 	case Opt_brl:
1400 		if (result.negated) {
1401 			/*
1402 			 * turn off mandatory locking in mode
1403 			 * if remote locking is turned off since the
1404 			 * local vfs will do advisory
1405 			 */
1406 			if (ctx->file_mode ==
1407 				(S_IALLUGO & ~(S_ISUID | S_IXGRP)))
1408 				ctx->file_mode = S_IALLUGO;
1409 			ctx->nobrl =  1;
1410 		} else
1411 			ctx->nobrl =  0;
1412 		break;
1413 	case Opt_handlecache:
1414 		if (result.negated)
1415 			ctx->nohandlecache = 1;
1416 		else
1417 			ctx->nohandlecache = 0;
1418 		break;
1419 	case Opt_forcemandatorylock:
1420 		ctx->mand_lock = 1;
1421 		break;
1422 	case Opt_setuids:
1423 		ctx->setuids = result.negated;
1424 		break;
1425 	case Opt_intr:
1426 		ctx->intr = !result.negated;
1427 		break;
1428 	case Opt_setuidfromacl:
1429 		ctx->setuidfromacl = 1;
1430 		break;
1431 	case Opt_strictsync:
1432 		ctx->nostrictsync = result.negated;
1433 		break;
1434 	case Opt_serverino:
1435 		ctx->server_ino = !result.negated;
1436 		break;
1437 	case Opt_rwpidforward:
1438 		ctx->rwpidforward = 1;
1439 		break;
1440 	case Opt_modesid:
1441 		ctx->mode_ace = 1;
1442 		break;
1443 	case Opt_cifsacl:
1444 		ctx->cifs_acl = !result.negated;
1445 		break;
1446 	case Opt_acl:
1447 		ctx->no_psx_acl = result.negated;
1448 		break;
1449 	case Opt_locallease:
1450 		ctx->local_lease = 1;
1451 		break;
1452 	case Opt_sign:
1453 		ctx->sign = true;
1454 		break;
1455 	case Opt_ignore_signature:
1456 		ctx->sign = true;
1457 		ctx->ignore_signature = true;
1458 		break;
1459 	case Opt_seal:
1460 		/* we do not do the following in secFlags because seal
1461 		 * is a per tree connection (mount) not a per socket
1462 		 * or per-smb connection option in the protocol
1463 		 * vol->secFlg |= CIFSSEC_MUST_SEAL;
1464 		 */
1465 		ctx->seal = 1;
1466 		break;
1467 	case Opt_noac:
1468 		pr_warn("Mount option noac not supported. Instead set /proc/fs/cifs/LookupCacheEnabled to 0\n");
1469 		break;
1470 	case Opt_fsc:
1471 #ifndef CONFIG_CIFS_FSCACHE
1472 		cifs_errorf(fc, "FS-Cache support needs CONFIG_CIFS_FSCACHE kernel config option set\n");
1473 		goto cifs_parse_mount_err;
1474 #endif
1475 		ctx->fsc = true;
1476 		break;
1477 	case Opt_mfsymlinks:
1478 		ctx->mfsymlinks = true;
1479 		break;
1480 	case Opt_multiuser:
1481 		ctx->multiuser = true;
1482 		break;
1483 	case Opt_sloppy:
1484 		ctx->sloppy = true;
1485 		break;
1486 	case Opt_nosharesock:
1487 		ctx->nosharesock = true;
1488 		break;
1489 	case Opt_persistent:
1490 		if (result.negated) {
1491 			ctx->nopersistent = true;
1492 			if (ctx->persistent) {
1493 				cifs_errorf(fc, "persistenthandles mount options conflict\n");
1494 				goto cifs_parse_mount_err;
1495 			}
1496 		} else {
1497 			ctx->persistent = true;
1498 			if ((ctx->nopersistent) || (ctx->resilient)) {
1499 				cifs_errorf(fc, "persistenthandles mount options conflict\n");
1500 				goto cifs_parse_mount_err;
1501 			}
1502 		}
1503 		break;
1504 	case Opt_resilient:
1505 		if (result.negated) {
1506 			ctx->resilient = false; /* already the default */
1507 		} else {
1508 			ctx->resilient = true;
1509 			if (ctx->persistent) {
1510 				cifs_errorf(fc, "persistenthandles mount options conflict\n");
1511 				goto cifs_parse_mount_err;
1512 			}
1513 		}
1514 		break;
1515 	case Opt_tcp_nodelay:
1516 		/* tcp nodelay should not usually be needed since we CORK/UNCORK the socket */
1517 		if (result.negated)
1518 			ctx->sockopt_tcp_nodelay = false;
1519 		else
1520 			ctx->sockopt_tcp_nodelay = true;
1521 		break;
1522 	case Opt_domainauto:
1523 		ctx->domainauto = true;
1524 		break;
1525 	case Opt_rdma:
1526 		ctx->rdma = true;
1527 		break;
1528 	}
1529 	/* case Opt_ignore: - is ignored as expected ... */
1530 
1531 	return 0;
1532 
1533  cifs_parse_mount_err:
1534 	kfree_sensitive(ctx->password);
1535 	return -EINVAL;
1536 }
1537 
1538 int smb3_init_fs_context(struct fs_context *fc)
1539 {
1540 	struct smb3_fs_context *ctx;
1541 	char *nodename = utsname()->nodename;
1542 	int i;
1543 
1544 	ctx = kzalloc(sizeof(struct smb3_fs_context), GFP_KERNEL);
1545 	if (unlikely(!ctx))
1546 		return -ENOMEM;
1547 
1548 	strscpy(ctx->workstation_name, nodename, sizeof(ctx->workstation_name));
1549 
1550 	/*
1551 	 * does not have to be perfect mapping since field is
1552 	 * informational, only used for servers that do not support
1553 	 * port 445 and it can be overridden at mount time
1554 	 */
1555 	memset(ctx->source_rfc1001_name, 0x20, RFC1001_NAME_LEN);
1556 	for (i = 0; i < strnlen(nodename, RFC1001_NAME_LEN); i++)
1557 		ctx->source_rfc1001_name[i] = toupper(nodename[i]);
1558 
1559 	ctx->source_rfc1001_name[RFC1001_NAME_LEN] = 0;
1560 	/*
1561 	 * null target name indicates to use *SMBSERVR default called name
1562 	 *  if we end up sending RFC1001 session initialize
1563 	 */
1564 	ctx->target_rfc1001_name[0] = 0;
1565 	ctx->cred_uid = current_uid();
1566 	ctx->linux_uid = current_uid();
1567 	ctx->linux_gid = current_gid();
1568 	/* By default 4MB read ahead size, 1MB block size */
1569 	ctx->bsize = CIFS_DEFAULT_IOSIZE; /* can improve cp performance significantly */
1570 	ctx->rasize = 0; /* 0 = use default (ie negotiated rsize) for read ahead pages */
1571 
1572 	/*
1573 	 * default to SFM style remapping of seven reserved characters
1574 	 * unless user overrides it or we negotiate CIFS POSIX where
1575 	 * it is unnecessary.  Can not simultaneously use more than one mapping
1576 	 * since then readdir could list files that open could not open
1577 	 */
1578 	ctx->remap = true;
1579 
1580 	/* default to only allowing write access to owner of the mount */
1581 	ctx->dir_mode = ctx->file_mode = S_IRUGO | S_IXUGO | S_IWUSR;
1582 
1583 	/* ctx->retry default is 0 (i.e. "soft" limited retry not hard retry) */
1584 	/* default is always to request posix paths. */
1585 	ctx->posix_paths = 1;
1586 	/* default to using server inode numbers where available */
1587 	ctx->server_ino = 1;
1588 
1589 	/* default is to use strict cifs caching semantics */
1590 	ctx->strict_io = true;
1591 
1592 	ctx->acregmax = CIFS_DEF_ACTIMEO;
1593 	ctx->acdirmax = CIFS_DEF_ACTIMEO;
1594 	ctx->closetimeo = SMB3_DEF_DCLOSETIMEO;
1595 
1596 	/* Most clients set timeout to 0, allows server to use its default */
1597 	ctx->handle_timeout = 0; /* See MS-SMB2 spec section 2.2.14.2.12 */
1598 
1599 	/* offer SMB2.1 and later (SMB3 etc). Secure and widely accepted */
1600 	ctx->ops = &smb30_operations;
1601 	ctx->vals = &smbdefault_values;
1602 
1603 	ctx->echo_interval = SMB_ECHO_INTERVAL_DEFAULT;
1604 
1605 	/* default to no multichannel (single server connection) */
1606 	ctx->multichannel = false;
1607 	ctx->max_channels = 1;
1608 
1609 	ctx->backupuid_specified = false; /* no backup intent for a user */
1610 	ctx->backupgid_specified = false; /* no backup intent for a group */
1611 
1612 /*
1613  *	short int override_uid = -1;
1614  *	short int override_gid = -1;
1615  *	char *nodename = strdup(utsname()->nodename);
1616  *	struct sockaddr *dstaddr = (struct sockaddr *)&vol->dstaddr;
1617  */
1618 
1619 	fc->fs_private = ctx;
1620 	fc->ops = &smb3_fs_context_ops;
1621 	return 0;
1622 }
1623 
1624 void
1625 smb3_cleanup_fs_context_contents(struct smb3_fs_context *ctx)
1626 {
1627 	if (ctx == NULL)
1628 		return;
1629 
1630 	/*
1631 	 * Make sure this stays in sync with smb3_fs_context_dup()
1632 	 */
1633 	kfree(ctx->username);
1634 	ctx->username = NULL;
1635 	kfree_sensitive(ctx->password);
1636 	ctx->password = NULL;
1637 	kfree(ctx->server_hostname);
1638 	ctx->server_hostname = NULL;
1639 	kfree(ctx->UNC);
1640 	ctx->UNC = NULL;
1641 	kfree(ctx->source);
1642 	ctx->source = NULL;
1643 	kfree(ctx->domainname);
1644 	ctx->domainname = NULL;
1645 	kfree(ctx->nodename);
1646 	ctx->nodename = NULL;
1647 	kfree(ctx->iocharset);
1648 	ctx->iocharset = NULL;
1649 	kfree(ctx->prepath);
1650 	ctx->prepath = NULL;
1651 	kfree(ctx->leaf_fullpath);
1652 	ctx->leaf_fullpath = NULL;
1653 }
1654 
1655 void
1656 smb3_cleanup_fs_context(struct smb3_fs_context *ctx)
1657 {
1658 	if (!ctx)
1659 		return;
1660 	smb3_cleanup_fs_context_contents(ctx);
1661 	kfree(ctx);
1662 }
1663 
1664 void smb3_update_mnt_flags(struct cifs_sb_info *cifs_sb)
1665 {
1666 	struct smb3_fs_context *ctx = cifs_sb->ctx;
1667 
1668 	if (ctx->nodfs)
1669 		cifs_sb->mnt_cifs_flags |= CIFS_MOUNT_NO_DFS;
1670 	else
1671 		cifs_sb->mnt_cifs_flags &= ~CIFS_MOUNT_NO_DFS;
1672 
1673 	if (ctx->noperm)
1674 		cifs_sb->mnt_cifs_flags |= CIFS_MOUNT_NO_PERM;
1675 	else
1676 		cifs_sb->mnt_cifs_flags &= ~CIFS_MOUNT_NO_PERM;
1677 
1678 	if (ctx->setuids)
1679 		cifs_sb->mnt_cifs_flags |= CIFS_MOUNT_SET_UID;
1680 	else
1681 		cifs_sb->mnt_cifs_flags &= ~CIFS_MOUNT_SET_UID;
1682 
1683 	if (ctx->setuidfromacl)
1684 		cifs_sb->mnt_cifs_flags |= CIFS_MOUNT_UID_FROM_ACL;
1685 	else
1686 		cifs_sb->mnt_cifs_flags &= ~CIFS_MOUNT_UID_FROM_ACL;
1687 
1688 	if (ctx->server_ino)
1689 		cifs_sb->mnt_cifs_flags |= CIFS_MOUNT_SERVER_INUM;
1690 	else
1691 		cifs_sb->mnt_cifs_flags &= ~CIFS_MOUNT_SERVER_INUM;
1692 
1693 	if (ctx->remap)
1694 		cifs_sb->mnt_cifs_flags |= CIFS_MOUNT_MAP_SFM_CHR;
1695 	else
1696 		cifs_sb->mnt_cifs_flags &= ~CIFS_MOUNT_MAP_SFM_CHR;
1697 
1698 	if (ctx->sfu_remap)
1699 		cifs_sb->mnt_cifs_flags |= CIFS_MOUNT_MAP_SPECIAL_CHR;
1700 	else
1701 		cifs_sb->mnt_cifs_flags &= ~CIFS_MOUNT_MAP_SPECIAL_CHR;
1702 
1703 	if (ctx->no_xattr)
1704 		cifs_sb->mnt_cifs_flags |= CIFS_MOUNT_NO_XATTR;
1705 	else
1706 		cifs_sb->mnt_cifs_flags &= ~CIFS_MOUNT_NO_XATTR;
1707 
1708 	if (ctx->sfu_emul)
1709 		cifs_sb->mnt_cifs_flags |= CIFS_MOUNT_UNX_EMUL;
1710 	else
1711 		cifs_sb->mnt_cifs_flags &= ~CIFS_MOUNT_UNX_EMUL;
1712 
1713 	if (ctx->nobrl)
1714 		cifs_sb->mnt_cifs_flags |= CIFS_MOUNT_NO_BRL;
1715 	else
1716 		cifs_sb->mnt_cifs_flags &= ~CIFS_MOUNT_NO_BRL;
1717 
1718 	if (ctx->nohandlecache)
1719 		cifs_sb->mnt_cifs_flags |= CIFS_MOUNT_NO_HANDLE_CACHE;
1720 	else
1721 		cifs_sb->mnt_cifs_flags &= ~CIFS_MOUNT_NO_HANDLE_CACHE;
1722 
1723 	if (ctx->nostrictsync)
1724 		cifs_sb->mnt_cifs_flags |= CIFS_MOUNT_NOSSYNC;
1725 	else
1726 		cifs_sb->mnt_cifs_flags &= ~CIFS_MOUNT_NOSSYNC;
1727 
1728 	if (ctx->mand_lock)
1729 		cifs_sb->mnt_cifs_flags |= CIFS_MOUNT_NOPOSIXBRL;
1730 	else
1731 		cifs_sb->mnt_cifs_flags &= ~CIFS_MOUNT_NOPOSIXBRL;
1732 
1733 	if (ctx->rwpidforward)
1734 		cifs_sb->mnt_cifs_flags |= CIFS_MOUNT_RWPIDFORWARD;
1735 	else
1736 		cifs_sb->mnt_cifs_flags &= ~CIFS_MOUNT_RWPIDFORWARD;
1737 
1738 	if (ctx->mode_ace)
1739 		cifs_sb->mnt_cifs_flags |= CIFS_MOUNT_MODE_FROM_SID;
1740 	else
1741 		cifs_sb->mnt_cifs_flags &= ~CIFS_MOUNT_MODE_FROM_SID;
1742 
1743 	if (ctx->cifs_acl)
1744 		cifs_sb->mnt_cifs_flags |= CIFS_MOUNT_CIFS_ACL;
1745 	else
1746 		cifs_sb->mnt_cifs_flags &= ~CIFS_MOUNT_CIFS_ACL;
1747 
1748 	if (ctx->backupuid_specified)
1749 		cifs_sb->mnt_cifs_flags |= CIFS_MOUNT_CIFS_BACKUPUID;
1750 	else
1751 		cifs_sb->mnt_cifs_flags &= ~CIFS_MOUNT_CIFS_BACKUPUID;
1752 
1753 	if (ctx->backupgid_specified)
1754 		cifs_sb->mnt_cifs_flags |= CIFS_MOUNT_CIFS_BACKUPGID;
1755 	else
1756 		cifs_sb->mnt_cifs_flags &= ~CIFS_MOUNT_CIFS_BACKUPGID;
1757 
1758 	if (ctx->override_uid)
1759 		cifs_sb->mnt_cifs_flags |= CIFS_MOUNT_OVERR_UID;
1760 	else
1761 		cifs_sb->mnt_cifs_flags &= ~CIFS_MOUNT_OVERR_UID;
1762 
1763 	if (ctx->override_gid)
1764 		cifs_sb->mnt_cifs_flags |= CIFS_MOUNT_OVERR_GID;
1765 	else
1766 		cifs_sb->mnt_cifs_flags &= ~CIFS_MOUNT_OVERR_GID;
1767 
1768 	if (ctx->dynperm)
1769 		cifs_sb->mnt_cifs_flags |= CIFS_MOUNT_DYNPERM;
1770 	else
1771 		cifs_sb->mnt_cifs_flags &= ~CIFS_MOUNT_DYNPERM;
1772 
1773 	if (ctx->fsc)
1774 		cifs_sb->mnt_cifs_flags |= CIFS_MOUNT_FSCACHE;
1775 	else
1776 		cifs_sb->mnt_cifs_flags &= ~CIFS_MOUNT_FSCACHE;
1777 
1778 	if (ctx->multiuser)
1779 		cifs_sb->mnt_cifs_flags |= (CIFS_MOUNT_MULTIUSER |
1780 					    CIFS_MOUNT_NO_PERM);
1781 	else
1782 		cifs_sb->mnt_cifs_flags &= ~CIFS_MOUNT_MULTIUSER;
1783 
1784 
1785 	if (ctx->strict_io)
1786 		cifs_sb->mnt_cifs_flags |= CIFS_MOUNT_STRICT_IO;
1787 	else
1788 		cifs_sb->mnt_cifs_flags &= ~CIFS_MOUNT_STRICT_IO;
1789 
1790 	if (ctx->direct_io)
1791 		cifs_sb->mnt_cifs_flags |= CIFS_MOUNT_DIRECT_IO;
1792 	else
1793 		cifs_sb->mnt_cifs_flags &= ~CIFS_MOUNT_DIRECT_IO;
1794 
1795 	if (ctx->mfsymlinks)
1796 		cifs_sb->mnt_cifs_flags |= CIFS_MOUNT_MF_SYMLINKS;
1797 	else
1798 		cifs_sb->mnt_cifs_flags &= ~CIFS_MOUNT_MF_SYMLINKS;
1799 	if (ctx->mfsymlinks) {
1800 		if (ctx->sfu_emul) {
1801 			/*
1802 			 * Our SFU ("Services for Unix" emulation does not allow
1803 			 * creating symlinks but does allow reading existing SFU
1804 			 * symlinks (it does allow both creating and reading SFU
1805 			 * style mknod and FIFOs though). When "mfsymlinks" and
1806 			 * "sfu" are both enabled at the same time, it allows
1807 			 * reading both types of symlinks, but will only create
1808 			 * them with mfsymlinks format. This allows better
1809 			 * Apple compatibility (probably better for Samba too)
1810 			 * while still recognizing old Windows style symlinks.
1811 			 */
1812 			cifs_dbg(VFS, "mount options mfsymlinks and sfu both enabled\n");
1813 		}
1814 	}
1815 	cifs_sb->mnt_cifs_flags &= ~CIFS_MOUNT_SHUTDOWN;
1816 
1817 	return;
1818 }
1819