xref: /linux/fs/smb/client/fs_context.c (revision 6de298ff13a807d12300bd616c6d3039987e6e87)
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 		break;
235 	default:
236 		cifs_errorf(fc, "bad security option: %s\n", value);
237 		return 1;
238 	}
239 
240 	return 0;
241 }
242 
243 static const match_table_t cifs_cacheflavor_tokens = {
244 	{ Opt_cache_loose, "loose" },
245 	{ Opt_cache_strict, "strict" },
246 	{ Opt_cache_none, "none" },
247 	{ Opt_cache_ro, "ro" },
248 	{ Opt_cache_rw, "singleclient" },
249 	{ Opt_cache_err, NULL }
250 };
251 
252 static int
253 cifs_parse_cache_flavor(struct fs_context *fc, char *value, struct smb3_fs_context *ctx)
254 {
255 	substring_t args[MAX_OPT_ARGS];
256 
257 	switch (match_token(value, cifs_cacheflavor_tokens, args)) {
258 	case Opt_cache_loose:
259 		ctx->direct_io = false;
260 		ctx->strict_io = false;
261 		ctx->cache_ro = false;
262 		ctx->cache_rw = false;
263 		break;
264 	case Opt_cache_strict:
265 		ctx->direct_io = false;
266 		ctx->strict_io = true;
267 		ctx->cache_ro = false;
268 		ctx->cache_rw = false;
269 		break;
270 	case Opt_cache_none:
271 		ctx->direct_io = true;
272 		ctx->strict_io = false;
273 		ctx->cache_ro = false;
274 		ctx->cache_rw = false;
275 		break;
276 	case Opt_cache_ro:
277 		ctx->direct_io = false;
278 		ctx->strict_io = false;
279 		ctx->cache_ro = true;
280 		ctx->cache_rw = false;
281 		break;
282 	case Opt_cache_rw:
283 		ctx->direct_io = false;
284 		ctx->strict_io = false;
285 		ctx->cache_ro = false;
286 		ctx->cache_rw = true;
287 		break;
288 	default:
289 		cifs_errorf(fc, "bad cache= option: %s\n", value);
290 		return 1;
291 	}
292 	return 0;
293 }
294 
295 #define DUP_CTX_STR(field)						\
296 do {									\
297 	if (ctx->field) {						\
298 		new_ctx->field = kstrdup(ctx->field, GFP_ATOMIC);	\
299 		if (new_ctx->field == NULL) {				\
300 			smb3_cleanup_fs_context_contents(new_ctx);	\
301 			return -ENOMEM;					\
302 		}							\
303 	}								\
304 } while (0)
305 
306 int
307 smb3_fs_context_dup(struct smb3_fs_context *new_ctx, struct smb3_fs_context *ctx)
308 {
309 	memcpy(new_ctx, ctx, sizeof(*ctx));
310 	new_ctx->prepath = NULL;
311 	new_ctx->nodename = NULL;
312 	new_ctx->username = NULL;
313 	new_ctx->password = NULL;
314 	new_ctx->server_hostname = NULL;
315 	new_ctx->domainname = NULL;
316 	new_ctx->UNC = NULL;
317 	new_ctx->source = NULL;
318 	new_ctx->iocharset = NULL;
319 	new_ctx->leaf_fullpath = NULL;
320 	/*
321 	 * Make sure to stay in sync with smb3_cleanup_fs_context_contents()
322 	 */
323 	DUP_CTX_STR(prepath);
324 	DUP_CTX_STR(username);
325 	DUP_CTX_STR(password);
326 	DUP_CTX_STR(server_hostname);
327 	DUP_CTX_STR(UNC);
328 	DUP_CTX_STR(source);
329 	DUP_CTX_STR(domainname);
330 	DUP_CTX_STR(nodename);
331 	DUP_CTX_STR(iocharset);
332 	DUP_CTX_STR(leaf_fullpath);
333 
334 	return 0;
335 }
336 
337 static int
338 cifs_parse_smb_version(struct fs_context *fc, char *value, struct smb3_fs_context *ctx, bool is_smb3)
339 {
340 	substring_t args[MAX_OPT_ARGS];
341 
342 	switch (match_token(value, cifs_smb_version_tokens, args)) {
343 #ifdef CONFIG_CIFS_ALLOW_INSECURE_LEGACY
344 	case Smb_1:
345 		if (disable_legacy_dialects) {
346 			cifs_errorf(fc, "mount with legacy dialect disabled\n");
347 			return 1;
348 		}
349 		if (is_smb3) {
350 			cifs_errorf(fc, "vers=1.0 (cifs) not permitted when mounting with smb3\n");
351 			return 1;
352 		}
353 		cifs_errorf(fc, "Use of the less secure dialect vers=1.0 is not recommended unless required for access to very old servers\n");
354 		ctx->ops = &smb1_operations;
355 		ctx->vals = &smb1_values;
356 		break;
357 	case Smb_20:
358 		if (disable_legacy_dialects) {
359 			cifs_errorf(fc, "mount with legacy dialect disabled\n");
360 			return 1;
361 		}
362 		if (is_smb3) {
363 			cifs_errorf(fc, "vers=2.0 not permitted when mounting with smb3\n");
364 			return 1;
365 		}
366 		ctx->ops = &smb20_operations;
367 		ctx->vals = &smb20_values;
368 		break;
369 #else
370 	case Smb_1:
371 		cifs_errorf(fc, "vers=1.0 (cifs) mount not permitted when legacy dialects disabled\n");
372 		return 1;
373 	case Smb_20:
374 		cifs_errorf(fc, "vers=2.0 mount not permitted when legacy dialects disabled\n");
375 		return 1;
376 #endif /* CIFS_ALLOW_INSECURE_LEGACY */
377 	case Smb_21:
378 		ctx->ops = &smb21_operations;
379 		ctx->vals = &smb21_values;
380 		break;
381 	case Smb_30:
382 		ctx->ops = &smb30_operations;
383 		ctx->vals = &smb30_values;
384 		break;
385 	case Smb_302:
386 		ctx->ops = &smb30_operations; /* currently identical with 3.0 */
387 		ctx->vals = &smb302_values;
388 		break;
389 	case Smb_311:
390 		ctx->ops = &smb311_operations;
391 		ctx->vals = &smb311_values;
392 		break;
393 	case Smb_3any:
394 		ctx->ops = &smb30_operations; /* currently identical with 3.0 */
395 		ctx->vals = &smb3any_values;
396 		break;
397 	case Smb_default:
398 		ctx->ops = &smb30_operations;
399 		ctx->vals = &smbdefault_values;
400 		break;
401 	default:
402 		cifs_errorf(fc, "Unknown vers= option specified: %s\n", value);
403 		return 1;
404 	}
405 	return 0;
406 }
407 
408 int smb3_parse_opt(const char *options, const char *key, char **val)
409 {
410 	int rc = -ENOENT;
411 	char *opts, *orig, *p;
412 
413 	orig = opts = kstrdup(options, GFP_KERNEL);
414 	if (!opts)
415 		return -ENOMEM;
416 
417 	while ((p = strsep(&opts, ","))) {
418 		char *nval;
419 
420 		if (!*p)
421 			continue;
422 		if (strncasecmp(p, key, strlen(key)))
423 			continue;
424 		nval = strchr(p, '=');
425 		if (nval) {
426 			if (nval == p)
427 				continue;
428 			*nval++ = 0;
429 			*val = kstrdup(nval, GFP_KERNEL);
430 			rc = !*val ? -ENOMEM : 0;
431 			goto out;
432 		}
433 	}
434 out:
435 	kfree(orig);
436 	return rc;
437 }
438 
439 /*
440  * Remove duplicate path delimiters. Windows is supposed to do that
441  * but there are some bugs that prevent rename from working if there are
442  * multiple delimiters.
443  *
444  * Return a sanitized duplicate of @path or NULL for empty prefix paths.
445  * Otherwise, return ERR_PTR.
446  *
447  * @gfp indicates the GFP_* flags for kstrdup.
448  * The caller is responsible for freeing the original.
449  */
450 #define IS_DELIM(c) ((c) == '/' || (c) == '\\')
451 char *cifs_sanitize_prepath(char *prepath, gfp_t gfp)
452 {
453 	char *cursor1 = prepath, *cursor2 = prepath;
454 	char *s;
455 
456 	/* skip all prepended delimiters */
457 	while (IS_DELIM(*cursor1))
458 		cursor1++;
459 
460 	/* copy the first letter */
461 	*cursor2 = *cursor1;
462 
463 	/* copy the remainder... */
464 	while (*(cursor1++)) {
465 		/* ... skipping all duplicated delimiters */
466 		if (IS_DELIM(*cursor1) && IS_DELIM(*cursor2))
467 			continue;
468 		*(++cursor2) = *cursor1;
469 	}
470 
471 	/* if the last character is a delimiter, skip it */
472 	if (IS_DELIM(*(cursor2 - 1)))
473 		cursor2--;
474 
475 	*cursor2 = '\0';
476 	if (!*prepath)
477 		return NULL;
478 	s = kstrdup(prepath, gfp);
479 	if (!s)
480 		return ERR_PTR(-ENOMEM);
481 	return s;
482 }
483 
484 /*
485  * Return full path based on the values of @ctx->{UNC,prepath}.
486  *
487  * It is assumed that both values were already parsed by smb3_parse_devname().
488  */
489 char *smb3_fs_context_fullpath(const struct smb3_fs_context *ctx, char dirsep)
490 {
491 	size_t ulen, plen;
492 	char *s;
493 
494 	ulen = strlen(ctx->UNC);
495 	plen = ctx->prepath ? strlen(ctx->prepath) + 1 : 0;
496 
497 	s = kmalloc(ulen + plen + 1, GFP_KERNEL);
498 	if (!s)
499 		return ERR_PTR(-ENOMEM);
500 	memcpy(s, ctx->UNC, ulen);
501 	if (plen) {
502 		s[ulen] = dirsep;
503 		memcpy(s + ulen + 1, ctx->prepath, plen);
504 	}
505 	s[ulen + plen] = '\0';
506 	convert_delimiter(s, dirsep);
507 	return s;
508 }
509 
510 /*
511  * Parse a devname into substrings and populate the ctx->UNC and ctx->prepath
512  * fields with the result. Returns 0 on success and an error otherwise
513  * (e.g. ENOMEM or EINVAL)
514  */
515 int
516 smb3_parse_devname(const char *devname, struct smb3_fs_context *ctx)
517 {
518 	char *pos;
519 	const char *delims = "/\\";
520 	size_t len;
521 	int rc;
522 
523 	if (unlikely(!devname || !*devname)) {
524 		cifs_dbg(VFS, "Device name not specified\n");
525 		return -EINVAL;
526 	}
527 
528 	/* make sure we have a valid UNC double delimiter prefix */
529 	len = strspn(devname, delims);
530 	if (len != 2)
531 		return -EINVAL;
532 
533 	/* find delimiter between host and sharename */
534 	pos = strpbrk(devname + 2, delims);
535 	if (!pos)
536 		return -EINVAL;
537 
538 	/* record the server hostname */
539 	kfree(ctx->server_hostname);
540 	ctx->server_hostname = kstrndup(devname + 2, pos - devname - 2, GFP_KERNEL);
541 	if (!ctx->server_hostname)
542 		return -ENOMEM;
543 
544 	/* skip past delimiter */
545 	++pos;
546 
547 	/* now go until next delimiter or end of string */
548 	len = strcspn(pos, delims);
549 	if (!len)
550 		return -EINVAL;
551 
552 	/* move "pos" up to delimiter or NULL */
553 	pos += len;
554 	kfree(ctx->UNC);
555 	ctx->UNC = kstrndup(devname, pos - devname, GFP_KERNEL);
556 	if (!ctx->UNC)
557 		return -ENOMEM;
558 
559 	convert_delimiter(ctx->UNC, '\\');
560 
561 	/* skip any delimiter */
562 	if (*pos == '/' || *pos == '\\')
563 		pos++;
564 
565 	kfree(ctx->prepath);
566 	ctx->prepath = NULL;
567 
568 	/* If pos is NULL then no prepath */
569 	if (!*pos)
570 		return 0;
571 
572 	ctx->prepath = cifs_sanitize_prepath(pos, GFP_KERNEL);
573 	if (IS_ERR(ctx->prepath)) {
574 		rc = PTR_ERR(ctx->prepath);
575 		ctx->prepath = NULL;
576 		return rc;
577 	}
578 
579 	return 0;
580 }
581 
582 static void smb3_fs_context_free(struct fs_context *fc);
583 static int smb3_fs_context_parse_param(struct fs_context *fc,
584 				       struct fs_parameter *param);
585 static int smb3_fs_context_parse_monolithic(struct fs_context *fc,
586 					    void *data);
587 static int smb3_get_tree(struct fs_context *fc);
588 static int smb3_reconfigure(struct fs_context *fc);
589 
590 static const struct fs_context_operations smb3_fs_context_ops = {
591 	.free			= smb3_fs_context_free,
592 	.parse_param		= smb3_fs_context_parse_param,
593 	.parse_monolithic	= smb3_fs_context_parse_monolithic,
594 	.get_tree		= smb3_get_tree,
595 	.reconfigure		= smb3_reconfigure,
596 };
597 
598 /*
599  * Parse a monolithic block of data from sys_mount().
600  * smb3_fs_context_parse_monolithic - Parse key[=val][,key[=val]]* mount data
601  * @ctx: The superblock configuration to fill in.
602  * @data: The data to parse
603  *
604  * Parse a blob of data that's in key[=val][,key[=val]]* form.  This can be
605  * called from the ->monolithic_mount_data() fs_context operation.
606  *
607  * Returns 0 on success or the error returned by the ->parse_option() fs_context
608  * operation on failure.
609  */
610 static int smb3_fs_context_parse_monolithic(struct fs_context *fc,
611 					   void *data)
612 {
613 	char *options = data, *key;
614 	int ret = 0;
615 
616 	if (!options)
617 		return 0;
618 
619 	ret = security_sb_eat_lsm_opts(options, &fc->security);
620 	if (ret)
621 		return ret;
622 
623 	/* BB Need to add support for sep= here TBD */
624 	while ((key = strsep(&options, ",")) != NULL) {
625 		size_t len;
626 		char *value;
627 
628 		if (*key == 0)
629 			break;
630 
631 		/* Check if following character is the deliminator If yes,
632 		 * we have encountered a double deliminator reset the NULL
633 		 * character to the deliminator
634 		 */
635 		while (options && options[0] == ',') {
636 			len = strlen(key);
637 			strcpy(key + len, options);
638 			options = strchr(options, ',');
639 			if (options)
640 				*options++ = 0;
641 		}
642 
643 
644 		len = 0;
645 		value = strchr(key, '=');
646 		if (value) {
647 			if (value == key)
648 				continue;
649 			*value++ = 0;
650 			len = strlen(value);
651 		}
652 
653 		ret = vfs_parse_fs_string(fc, key, value, len);
654 		if (ret < 0)
655 			break;
656 	}
657 
658 	return ret;
659 }
660 
661 /*
662  * Validate the preparsed information in the config.
663  */
664 static int smb3_fs_context_validate(struct fs_context *fc)
665 {
666 	struct smb3_fs_context *ctx = smb3_fc2context(fc);
667 
668 	if (ctx->rdma && ctx->vals->protocol_id < SMB30_PROT_ID) {
669 		cifs_errorf(fc, "SMB Direct requires Version >=3.0\n");
670 		return -EOPNOTSUPP;
671 	}
672 
673 #ifndef CONFIG_KEYS
674 	/* Muliuser mounts require CONFIG_KEYS support */
675 	if (ctx->multiuser) {
676 		cifs_errorf(fc, "Multiuser mounts require kernels with CONFIG_KEYS enabled\n");
677 		return -1;
678 	}
679 #endif
680 
681 	if (ctx->got_version == false)
682 		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");
683 
684 
685 	if (!ctx->UNC) {
686 		cifs_errorf(fc, "CIFS mount error: No usable UNC path provided in device string!\n");
687 		return -1;
688 	}
689 
690 	/* make sure UNC has a share name */
691 	if (strlen(ctx->UNC) < 3 || !strchr(ctx->UNC + 3, '\\')) {
692 		cifs_errorf(fc, "Malformed UNC. Unable to find share name.\n");
693 		return -ENOENT;
694 	}
695 
696 	if (!ctx->got_ip) {
697 		int len;
698 		const char *slash;
699 
700 		/* No ip= option specified? Try to get it from UNC */
701 		/* Use the address part of the UNC. */
702 		slash = strchr(&ctx->UNC[2], '\\');
703 		len = slash - &ctx->UNC[2];
704 		if (!cifs_convert_address((struct sockaddr *)&ctx->dstaddr,
705 					  &ctx->UNC[2], len)) {
706 			pr_err("Unable to determine destination address\n");
707 			return -EHOSTUNREACH;
708 		}
709 	}
710 
711 	/* set the port that we got earlier */
712 	cifs_set_port((struct sockaddr *)&ctx->dstaddr, ctx->port);
713 
714 	if (ctx->override_uid && !ctx->uid_specified) {
715 		ctx->override_uid = 0;
716 		pr_notice("ignoring forceuid mount option specified with no uid= option\n");
717 	}
718 
719 	if (ctx->override_gid && !ctx->gid_specified) {
720 		ctx->override_gid = 0;
721 		pr_notice("ignoring forcegid mount option specified with no gid= option\n");
722 	}
723 
724 	return 0;
725 }
726 
727 static int smb3_get_tree_common(struct fs_context *fc)
728 {
729 	struct smb3_fs_context *ctx = smb3_fc2context(fc);
730 	struct dentry *root;
731 	int rc = 0;
732 
733 	root = cifs_smb3_do_mount(fc->fs_type, 0, ctx);
734 	if (IS_ERR(root))
735 		return PTR_ERR(root);
736 
737 	fc->root = root;
738 
739 	return rc;
740 }
741 
742 /*
743  * Create an SMB3 superblock from the parameters passed.
744  */
745 static int smb3_get_tree(struct fs_context *fc)
746 {
747 	int err = smb3_fs_context_validate(fc);
748 	int ret;
749 
750 	if (err)
751 		return err;
752 	mutex_lock(&cifs_mount_mutex);
753 	ret = smb3_get_tree_common(fc);
754 	mutex_unlock(&cifs_mount_mutex);
755 	return ret;
756 }
757 
758 static void smb3_fs_context_free(struct fs_context *fc)
759 {
760 	struct smb3_fs_context *ctx = smb3_fc2context(fc);
761 
762 	smb3_cleanup_fs_context(ctx);
763 }
764 
765 /*
766  * Compare the old and new proposed context during reconfigure
767  * and check if the changes are compatible.
768  */
769 static int smb3_verify_reconfigure_ctx(struct fs_context *fc,
770 				       struct smb3_fs_context *new_ctx,
771 				       struct smb3_fs_context *old_ctx)
772 {
773 	if (new_ctx->posix_paths != old_ctx->posix_paths) {
774 		cifs_errorf(fc, "can not change posixpaths during remount\n");
775 		return -EINVAL;
776 	}
777 	if (new_ctx->sectype != old_ctx->sectype) {
778 		cifs_errorf(fc, "can not change sec during remount\n");
779 		return -EINVAL;
780 	}
781 	if (new_ctx->multiuser != old_ctx->multiuser) {
782 		cifs_errorf(fc, "can not change multiuser during remount\n");
783 		return -EINVAL;
784 	}
785 	if (new_ctx->UNC &&
786 	    (!old_ctx->UNC || strcmp(new_ctx->UNC, old_ctx->UNC))) {
787 		cifs_errorf(fc, "can not change UNC during remount\n");
788 		return -EINVAL;
789 	}
790 	if (new_ctx->username &&
791 	    (!old_ctx->username || strcmp(new_ctx->username, old_ctx->username))) {
792 		cifs_errorf(fc, "can not change username during remount\n");
793 		return -EINVAL;
794 	}
795 	if (new_ctx->password &&
796 	    (!old_ctx->password || strcmp(new_ctx->password, old_ctx->password))) {
797 		cifs_errorf(fc, "can not change password during remount\n");
798 		return -EINVAL;
799 	}
800 	if (new_ctx->domainname &&
801 	    (!old_ctx->domainname || strcmp(new_ctx->domainname, old_ctx->domainname))) {
802 		cifs_errorf(fc, "can not change domainname during remount\n");
803 		return -EINVAL;
804 	}
805 	if (strcmp(new_ctx->workstation_name, old_ctx->workstation_name)) {
806 		cifs_errorf(fc, "can not change workstation_name during remount\n");
807 		return -EINVAL;
808 	}
809 	if (new_ctx->nodename &&
810 	    (!old_ctx->nodename || strcmp(new_ctx->nodename, old_ctx->nodename))) {
811 		cifs_errorf(fc, "can not change nodename during remount\n");
812 		return -EINVAL;
813 	}
814 	if (new_ctx->iocharset &&
815 	    (!old_ctx->iocharset || strcmp(new_ctx->iocharset, old_ctx->iocharset))) {
816 		cifs_errorf(fc, "can not change iocharset during remount\n");
817 		return -EINVAL;
818 	}
819 
820 	return 0;
821 }
822 
823 #define STEAL_STRING(cifs_sb, ctx, field)				\
824 do {									\
825 	kfree(ctx->field);						\
826 	ctx->field = cifs_sb->ctx->field;				\
827 	cifs_sb->ctx->field = NULL;					\
828 } while (0)
829 
830 #define STEAL_STRING_SENSITIVE(cifs_sb, ctx, field)			\
831 do {									\
832 	kfree_sensitive(ctx->field);					\
833 	ctx->field = cifs_sb->ctx->field;				\
834 	cifs_sb->ctx->field = NULL;					\
835 } while (0)
836 
837 static int smb3_reconfigure(struct fs_context *fc)
838 {
839 	struct smb3_fs_context *ctx = smb3_fc2context(fc);
840 	struct dentry *root = fc->root;
841 	struct cifs_sb_info *cifs_sb = CIFS_SB(root->d_sb);
842 	int rc;
843 
844 	rc = smb3_verify_reconfigure_ctx(fc, ctx, cifs_sb->ctx);
845 	if (rc)
846 		return rc;
847 
848 	/*
849 	 * We can not change UNC/username/password/domainname/
850 	 * workstation_name/nodename/iocharset
851 	 * during reconnect so ignore what we have in the new context and
852 	 * just use what we already have in cifs_sb->ctx.
853 	 */
854 	STEAL_STRING(cifs_sb, ctx, UNC);
855 	STEAL_STRING(cifs_sb, ctx, source);
856 	STEAL_STRING(cifs_sb, ctx, username);
857 	STEAL_STRING_SENSITIVE(cifs_sb, ctx, password);
858 	STEAL_STRING(cifs_sb, ctx, domainname);
859 	STEAL_STRING(cifs_sb, ctx, nodename);
860 	STEAL_STRING(cifs_sb, ctx, iocharset);
861 
862 	/* if rsize or wsize not passed in on remount, use previous values */
863 	if (ctx->rsize == 0)
864 		ctx->rsize = cifs_sb->ctx->rsize;
865 	if (ctx->wsize == 0)
866 		ctx->wsize = cifs_sb->ctx->wsize;
867 
868 
869 	smb3_cleanup_fs_context_contents(cifs_sb->ctx);
870 	rc = smb3_fs_context_dup(cifs_sb->ctx, ctx);
871 	smb3_update_mnt_flags(cifs_sb);
872 #ifdef CONFIG_CIFS_DFS_UPCALL
873 	if (!rc)
874 		rc = dfs_cache_remount_fs(cifs_sb);
875 #endif
876 
877 	return rc;
878 }
879 
880 static int smb3_fs_context_parse_param(struct fs_context *fc,
881 				      struct fs_parameter *param)
882 {
883 	struct fs_parse_result result;
884 	struct smb3_fs_context *ctx = smb3_fc2context(fc);
885 	int i, opt;
886 	bool is_smb3 = !strcmp(fc->fs_type->name, "smb3");
887 	bool skip_parsing = false;
888 	kuid_t uid;
889 	kgid_t gid;
890 
891 	cifs_dbg(FYI, "CIFS: parsing cifs mount option '%s'\n", param->key);
892 
893 	/*
894 	 * fs_parse can not handle string options with an empty value so
895 	 * we will need special handling of them.
896 	 */
897 	if (param->type == fs_value_is_string && param->string[0] == 0) {
898 		if (!strcmp("pass", param->key) || !strcmp("password", param->key)) {
899 			skip_parsing = true;
900 			opt = Opt_pass;
901 		} else if (!strcmp("user", param->key) || !strcmp("username", param->key)) {
902 			skip_parsing = true;
903 			opt = Opt_user;
904 		}
905 	}
906 
907 	if (!skip_parsing) {
908 		opt = fs_parse(fc, smb3_fs_parameters, param, &result);
909 		if (opt < 0)
910 			return ctx->sloppy ? 1 : opt;
911 	}
912 
913 	switch (opt) {
914 	case Opt_compress:
915 		ctx->compression = UNKNOWN_TYPE;
916 		cifs_dbg(VFS,
917 			"SMB3 compression support is experimental\n");
918 		break;
919 	case Opt_nodfs:
920 		ctx->nodfs = 1;
921 		break;
922 	case Opt_hard:
923 		if (result.negated) {
924 			if (ctx->retry == 1)
925 				cifs_dbg(VFS, "conflicting hard vs. soft mount options\n");
926 			ctx->retry = 0;
927 		} else
928 			ctx->retry = 1;
929 		break;
930 	case Opt_soft:
931 		if (result.negated)
932 			ctx->retry = 1;
933 		else {
934 			if (ctx->retry == 1)
935 				cifs_dbg(VFS, "conflicting hard vs soft mount options\n");
936 			ctx->retry = 0;
937 		}
938 		break;
939 	case Opt_mapposix:
940 		if (result.negated)
941 			ctx->remap = false;
942 		else {
943 			ctx->remap = true;
944 			ctx->sfu_remap = false; /* disable SFU mapping */
945 		}
946 		break;
947 	case Opt_mapchars:
948 		if (result.negated)
949 			ctx->sfu_remap = false;
950 		else {
951 			ctx->sfu_remap = true;
952 			ctx->remap = false; /* disable SFM (mapposix) mapping */
953 		}
954 		break;
955 	case Opt_user_xattr:
956 		if (result.negated)
957 			ctx->no_xattr = 1;
958 		else
959 			ctx->no_xattr = 0;
960 		break;
961 	case Opt_forceuid:
962 		if (result.negated)
963 			ctx->override_uid = 0;
964 		else
965 			ctx->override_uid = 1;
966 		break;
967 	case Opt_forcegid:
968 		if (result.negated)
969 			ctx->override_gid = 0;
970 		else
971 			ctx->override_gid = 1;
972 		break;
973 	case Opt_perm:
974 		if (result.negated)
975 			ctx->noperm = 1;
976 		else
977 			ctx->noperm = 0;
978 		break;
979 	case Opt_dynperm:
980 		if (result.negated)
981 			ctx->dynperm = 0;
982 		else
983 			ctx->dynperm = 1;
984 		break;
985 	case Opt_sfu:
986 		if (result.negated)
987 			ctx->sfu_emul = 0;
988 		else
989 			ctx->sfu_emul = 1;
990 		break;
991 	case Opt_noblocksend:
992 		ctx->noblocksnd = 1;
993 		break;
994 	case Opt_noautotune:
995 		ctx->noautotune = 1;
996 		break;
997 	case Opt_nolease:
998 		ctx->no_lease = 1;
999 		break;
1000 	case Opt_nosparse:
1001 		ctx->no_sparse = 1;
1002 		break;
1003 	case Opt_nodelete:
1004 		ctx->nodelete = 1;
1005 		break;
1006 	case Opt_multichannel:
1007 		if (result.negated) {
1008 			ctx->multichannel = false;
1009 			ctx->max_channels = 1;
1010 		} else {
1011 			ctx->multichannel = true;
1012 			/* if number of channels not specified, default to 2 */
1013 			if (ctx->max_channels < 2)
1014 				ctx->max_channels = 2;
1015 		}
1016 		break;
1017 	case Opt_uid:
1018 		uid = make_kuid(current_user_ns(), result.uint_32);
1019 		if (!uid_valid(uid))
1020 			goto cifs_parse_mount_err;
1021 		ctx->linux_uid = uid;
1022 		ctx->uid_specified = true;
1023 		break;
1024 	case Opt_cruid:
1025 		uid = make_kuid(current_user_ns(), result.uint_32);
1026 		if (!uid_valid(uid))
1027 			goto cifs_parse_mount_err;
1028 		ctx->cred_uid = uid;
1029 		ctx->cruid_specified = true;
1030 		break;
1031 	case Opt_backupuid:
1032 		uid = make_kuid(current_user_ns(), result.uint_32);
1033 		if (!uid_valid(uid))
1034 			goto cifs_parse_mount_err;
1035 		ctx->backupuid = uid;
1036 		ctx->backupuid_specified = true;
1037 		break;
1038 	case Opt_backupgid:
1039 		gid = make_kgid(current_user_ns(), result.uint_32);
1040 		if (!gid_valid(gid))
1041 			goto cifs_parse_mount_err;
1042 		ctx->backupgid = gid;
1043 		ctx->backupgid_specified = true;
1044 		break;
1045 	case Opt_gid:
1046 		gid = make_kgid(current_user_ns(), result.uint_32);
1047 		if (!gid_valid(gid))
1048 			goto cifs_parse_mount_err;
1049 		ctx->linux_gid = gid;
1050 		ctx->gid_specified = true;
1051 		break;
1052 	case Opt_port:
1053 		ctx->port = result.uint_32;
1054 		break;
1055 	case Opt_file_mode:
1056 		ctx->file_mode = result.uint_32;
1057 		break;
1058 	case Opt_dirmode:
1059 		ctx->dir_mode = result.uint_32;
1060 		break;
1061 	case Opt_min_enc_offload:
1062 		ctx->min_offload = result.uint_32;
1063 		break;
1064 	case Opt_blocksize:
1065 		/*
1066 		 * inode blocksize realistically should never need to be
1067 		 * less than 16K or greater than 16M and default is 1MB.
1068 		 * Note that small inode block sizes (e.g. 64K) can lead
1069 		 * to very poor performance of common tools like cp and scp
1070 		 */
1071 		if ((result.uint_32 < CIFS_MAX_MSGSIZE) ||
1072 		   (result.uint_32 > (4 * SMB3_DEFAULT_IOSIZE))) {
1073 			cifs_errorf(fc, "%s: Invalid blocksize\n",
1074 				__func__);
1075 			goto cifs_parse_mount_err;
1076 		}
1077 		ctx->bsize = result.uint_32;
1078 		ctx->got_bsize = true;
1079 		break;
1080 	case Opt_rasize:
1081 		/*
1082 		 * readahead size realistically should never need to be
1083 		 * less than 1M (CIFS_DEFAULT_IOSIZE) or greater than 32M
1084 		 * (perhaps an exception should be considered in the
1085 		 * for the case of a large number of channels
1086 		 * when multichannel is negotiated) since that would lead
1087 		 * to plenty of parallel I/O in flight to the server.
1088 		 * Note that smaller read ahead sizes would
1089 		 * hurt performance of common tools like cp and scp
1090 		 * which often trigger sequential i/o with read ahead
1091 		 */
1092 		if ((result.uint_32 > (8 * SMB3_DEFAULT_IOSIZE)) ||
1093 		    (result.uint_32 < CIFS_DEFAULT_IOSIZE)) {
1094 			cifs_errorf(fc, "%s: Invalid rasize %d vs. %d\n",
1095 				__func__, result.uint_32, SMB3_DEFAULT_IOSIZE);
1096 			goto cifs_parse_mount_err;
1097 		}
1098 		ctx->rasize = result.uint_32;
1099 		break;
1100 	case Opt_rsize:
1101 		ctx->rsize = result.uint_32;
1102 		ctx->got_rsize = true;
1103 		break;
1104 	case Opt_wsize:
1105 		ctx->wsize = result.uint_32;
1106 		ctx->got_wsize = true;
1107 		break;
1108 	case Opt_acregmax:
1109 		ctx->acregmax = HZ * result.uint_32;
1110 		if (ctx->acregmax > CIFS_MAX_ACTIMEO) {
1111 			cifs_errorf(fc, "acregmax too large\n");
1112 			goto cifs_parse_mount_err;
1113 		}
1114 		break;
1115 	case Opt_acdirmax:
1116 		ctx->acdirmax = HZ * result.uint_32;
1117 		if (ctx->acdirmax > CIFS_MAX_ACTIMEO) {
1118 			cifs_errorf(fc, "acdirmax too large\n");
1119 			goto cifs_parse_mount_err;
1120 		}
1121 		break;
1122 	case Opt_actimeo:
1123 		if (HZ * result.uint_32 > CIFS_MAX_ACTIMEO) {
1124 			cifs_errorf(fc, "timeout too large\n");
1125 			goto cifs_parse_mount_err;
1126 		}
1127 		if ((ctx->acdirmax != CIFS_DEF_ACTIMEO) ||
1128 		    (ctx->acregmax != CIFS_DEF_ACTIMEO)) {
1129 			cifs_errorf(fc, "actimeo ignored since acregmax or acdirmax specified\n");
1130 			break;
1131 		}
1132 		ctx->acdirmax = ctx->acregmax = HZ * result.uint_32;
1133 		break;
1134 	case Opt_closetimeo:
1135 		ctx->closetimeo = HZ * result.uint_32;
1136 		if (ctx->closetimeo > SMB3_MAX_DCLOSETIMEO) {
1137 			cifs_errorf(fc, "closetimeo too large\n");
1138 			goto cifs_parse_mount_err;
1139 		}
1140 		break;
1141 	case Opt_echo_interval:
1142 		ctx->echo_interval = result.uint_32;
1143 		break;
1144 	case Opt_snapshot:
1145 		ctx->snapshot_time = result.uint_64;
1146 		break;
1147 	case Opt_max_credits:
1148 		if (result.uint_32 < 20 || result.uint_32 > 60000) {
1149 			cifs_errorf(fc, "%s: Invalid max_credits value\n",
1150 				 __func__);
1151 			goto cifs_parse_mount_err;
1152 		}
1153 		ctx->max_credits = result.uint_32;
1154 		break;
1155 	case Opt_max_channels:
1156 		if (result.uint_32 < 1 || result.uint_32 > CIFS_MAX_CHANNELS) {
1157 			cifs_errorf(fc, "%s: Invalid max_channels value, needs to be 1-%d\n",
1158 				 __func__, CIFS_MAX_CHANNELS);
1159 			goto cifs_parse_mount_err;
1160 		}
1161 		ctx->max_channels = result.uint_32;
1162 		/* If more than one channel requested ... they want multichan */
1163 		if (result.uint_32 > 1)
1164 			ctx->multichannel = true;
1165 		break;
1166 	case Opt_handletimeout:
1167 		ctx->handle_timeout = result.uint_32;
1168 		if (ctx->handle_timeout > SMB3_MAX_HANDLE_TIMEOUT) {
1169 			cifs_errorf(fc, "Invalid handle cache timeout, longer than 16 minutes\n");
1170 			goto cifs_parse_mount_err;
1171 		}
1172 		break;
1173 	case Opt_source:
1174 		kfree(ctx->UNC);
1175 		ctx->UNC = NULL;
1176 		switch (smb3_parse_devname(param->string, ctx)) {
1177 		case 0:
1178 			break;
1179 		case -ENOMEM:
1180 			cifs_errorf(fc, "Unable to allocate memory for devname\n");
1181 			goto cifs_parse_mount_err;
1182 		case -EINVAL:
1183 			cifs_errorf(fc, "Malformed UNC in devname\n");
1184 			goto cifs_parse_mount_err;
1185 		default:
1186 			cifs_errorf(fc, "Unknown error parsing devname\n");
1187 			goto cifs_parse_mount_err;
1188 		}
1189 		ctx->source = smb3_fs_context_fullpath(ctx, '/');
1190 		if (IS_ERR(ctx->source)) {
1191 			ctx->source = NULL;
1192 			cifs_errorf(fc, "OOM when copying UNC string\n");
1193 			goto cifs_parse_mount_err;
1194 		}
1195 		fc->source = kstrdup(ctx->source, GFP_KERNEL);
1196 		if (fc->source == NULL) {
1197 			cifs_errorf(fc, "OOM when copying UNC string\n");
1198 			goto cifs_parse_mount_err;
1199 		}
1200 		break;
1201 	case Opt_user:
1202 		kfree(ctx->username);
1203 		ctx->username = NULL;
1204 		if (strlen(param->string) == 0) {
1205 			/* null user, ie. anonymous authentication */
1206 			ctx->nullauth = 1;
1207 			break;
1208 		}
1209 
1210 		if (strnlen(param->string, CIFS_MAX_USERNAME_LEN) >
1211 		    CIFS_MAX_USERNAME_LEN) {
1212 			pr_warn("username too long\n");
1213 			goto cifs_parse_mount_err;
1214 		}
1215 		ctx->username = kstrdup(param->string, GFP_KERNEL);
1216 		if (ctx->username == NULL) {
1217 			cifs_errorf(fc, "OOM when copying username string\n");
1218 			goto cifs_parse_mount_err;
1219 		}
1220 		break;
1221 	case Opt_pass:
1222 		kfree_sensitive(ctx->password);
1223 		ctx->password = NULL;
1224 		if (strlen(param->string) == 0)
1225 			break;
1226 
1227 		ctx->password = kstrdup(param->string, GFP_KERNEL);
1228 		if (ctx->password == NULL) {
1229 			cifs_errorf(fc, "OOM when copying password string\n");
1230 			goto cifs_parse_mount_err;
1231 		}
1232 		break;
1233 	case Opt_ip:
1234 		if (strlen(param->string) == 0) {
1235 			ctx->got_ip = false;
1236 			break;
1237 		}
1238 		if (!cifs_convert_address((struct sockaddr *)&ctx->dstaddr,
1239 					  param->string,
1240 					  strlen(param->string))) {
1241 			pr_err("bad ip= option (%s)\n", param->string);
1242 			goto cifs_parse_mount_err;
1243 		}
1244 		ctx->got_ip = true;
1245 		break;
1246 	case Opt_domain:
1247 		if (strnlen(param->string, CIFS_MAX_DOMAINNAME_LEN)
1248 				== CIFS_MAX_DOMAINNAME_LEN) {
1249 			pr_warn("domain name too long\n");
1250 			goto cifs_parse_mount_err;
1251 		}
1252 
1253 		kfree(ctx->domainname);
1254 		ctx->domainname = kstrdup(param->string, GFP_KERNEL);
1255 		if (ctx->domainname == NULL) {
1256 			cifs_errorf(fc, "OOM when copying domainname string\n");
1257 			goto cifs_parse_mount_err;
1258 		}
1259 		cifs_dbg(FYI, "Domain name set\n");
1260 		break;
1261 	case Opt_srcaddr:
1262 		if (!cifs_convert_address(
1263 				(struct sockaddr *)&ctx->srcaddr,
1264 				param->string, strlen(param->string))) {
1265 			pr_warn("Could not parse srcaddr: %s\n",
1266 				param->string);
1267 			goto cifs_parse_mount_err;
1268 		}
1269 		break;
1270 	case Opt_iocharset:
1271 		if (strnlen(param->string, 1024) >= 65) {
1272 			pr_warn("iocharset name too long\n");
1273 			goto cifs_parse_mount_err;
1274 		}
1275 
1276 		if (strncasecmp(param->string, "default", 7) != 0) {
1277 			kfree(ctx->iocharset);
1278 			ctx->iocharset = kstrdup(param->string, GFP_KERNEL);
1279 			if (ctx->iocharset == NULL) {
1280 				cifs_errorf(fc, "OOM when copying iocharset string\n");
1281 				goto cifs_parse_mount_err;
1282 			}
1283 		}
1284 		/* if iocharset not set then load_nls_default
1285 		 * is used by caller
1286 		 */
1287 		cifs_dbg(FYI, "iocharset set to %s\n", ctx->iocharset);
1288 		break;
1289 	case Opt_netbiosname:
1290 		memset(ctx->source_rfc1001_name, 0x20,
1291 			RFC1001_NAME_LEN);
1292 		/*
1293 		 * FIXME: are there cases in which a comma can
1294 		 * be valid in workstation netbios name (and
1295 		 * need special handling)?
1296 		 */
1297 		for (i = 0; i < RFC1001_NAME_LEN; i++) {
1298 			/* don't ucase netbiosname for user */
1299 			if (param->string[i] == 0)
1300 				break;
1301 			ctx->source_rfc1001_name[i] = param->string[i];
1302 		}
1303 		/* The string has 16th byte zero still from
1304 		 * set at top of the function
1305 		 */
1306 		if (i == RFC1001_NAME_LEN && param->string[i] != 0)
1307 			pr_warn("netbiosname longer than 15 truncated\n");
1308 		break;
1309 	case Opt_servern:
1310 		/* last byte, type, is 0x20 for servr type */
1311 		memset(ctx->target_rfc1001_name, 0x20,
1312 			RFC1001_NAME_LEN_WITH_NULL);
1313 		/*
1314 		 * BB are there cases in which a comma can be valid in this
1315 		 * workstation netbios name (and need special handling)?
1316 		 */
1317 
1318 		/* user or mount helper must uppercase the netbios name */
1319 		for (i = 0; i < 15; i++) {
1320 			if (param->string[i] == 0)
1321 				break;
1322 			ctx->target_rfc1001_name[i] = param->string[i];
1323 		}
1324 
1325 		/* The string has 16th byte zero still from set at top of function */
1326 		if (i == RFC1001_NAME_LEN && param->string[i] != 0)
1327 			pr_warn("server netbiosname longer than 15 truncated\n");
1328 		break;
1329 	case Opt_ver:
1330 		/* version of mount userspace tools, not dialect */
1331 		/* If interface changes in mount.cifs bump to new ver */
1332 		if (strncasecmp(param->string, "1", 1) == 0) {
1333 			if (strlen(param->string) > 1) {
1334 				pr_warn("Bad mount helper ver=%s. Did you want SMB1 (CIFS) dialect and mean to type vers=1.0 instead?\n",
1335 					param->string);
1336 				goto cifs_parse_mount_err;
1337 			}
1338 			/* This is the default */
1339 			break;
1340 		}
1341 		/* For all other value, error */
1342 		pr_warn("Invalid mount helper version specified\n");
1343 		goto cifs_parse_mount_err;
1344 	case Opt_vers:
1345 		/* protocol version (dialect) */
1346 		if (cifs_parse_smb_version(fc, param->string, ctx, is_smb3) != 0)
1347 			goto cifs_parse_mount_err;
1348 		ctx->got_version = true;
1349 		break;
1350 	case Opt_sec:
1351 		if (cifs_parse_security_flavors(fc, param->string, ctx) != 0)
1352 			goto cifs_parse_mount_err;
1353 		break;
1354 	case Opt_cache:
1355 		if (cifs_parse_cache_flavor(fc, param->string, ctx) != 0)
1356 			goto cifs_parse_mount_err;
1357 		break;
1358 	case Opt_witness:
1359 #ifndef CONFIG_CIFS_SWN_UPCALL
1360 		cifs_errorf(fc, "Witness support needs CONFIG_CIFS_SWN_UPCALL config option\n");
1361 			goto cifs_parse_mount_err;
1362 #endif
1363 		ctx->witness = true;
1364 		pr_warn_once("Witness protocol support is experimental\n");
1365 		break;
1366 	case Opt_rootfs:
1367 #ifndef CONFIG_CIFS_ROOT
1368 		cifs_dbg(VFS, "rootfs support requires CONFIG_CIFS_ROOT config option\n");
1369 		goto cifs_parse_mount_err;
1370 #endif
1371 		ctx->rootfs = true;
1372 		break;
1373 	case Opt_posixpaths:
1374 		if (result.negated)
1375 			ctx->posix_paths = 0;
1376 		else
1377 			ctx->posix_paths = 1;
1378 		break;
1379 	case Opt_unix:
1380 		if (result.negated) {
1381 			if (ctx->linux_ext == 1)
1382 				pr_warn_once("conflicting posix mount options specified\n");
1383 			ctx->linux_ext = 0;
1384 			ctx->no_linux_ext = 1;
1385 		} else {
1386 			if (ctx->no_linux_ext == 1)
1387 				pr_warn_once("conflicting posix mount options specified\n");
1388 			ctx->linux_ext = 1;
1389 			ctx->no_linux_ext = 0;
1390 		}
1391 		break;
1392 	case Opt_nocase:
1393 		ctx->nocase = 1;
1394 		break;
1395 	case Opt_brl:
1396 		if (result.negated) {
1397 			/*
1398 			 * turn off mandatory locking in mode
1399 			 * if remote locking is turned off since the
1400 			 * local vfs will do advisory
1401 			 */
1402 			if (ctx->file_mode ==
1403 				(S_IALLUGO & ~(S_ISUID | S_IXGRP)))
1404 				ctx->file_mode = S_IALLUGO;
1405 			ctx->nobrl =  1;
1406 		} else
1407 			ctx->nobrl =  0;
1408 		break;
1409 	case Opt_handlecache:
1410 		if (result.negated)
1411 			ctx->nohandlecache = 1;
1412 		else
1413 			ctx->nohandlecache = 0;
1414 		break;
1415 	case Opt_forcemandatorylock:
1416 		ctx->mand_lock = 1;
1417 		break;
1418 	case Opt_setuids:
1419 		ctx->setuids = result.negated;
1420 		break;
1421 	case Opt_intr:
1422 		ctx->intr = !result.negated;
1423 		break;
1424 	case Opt_setuidfromacl:
1425 		ctx->setuidfromacl = 1;
1426 		break;
1427 	case Opt_strictsync:
1428 		ctx->nostrictsync = result.negated;
1429 		break;
1430 	case Opt_serverino:
1431 		ctx->server_ino = !result.negated;
1432 		break;
1433 	case Opt_rwpidforward:
1434 		ctx->rwpidforward = 1;
1435 		break;
1436 	case Opt_modesid:
1437 		ctx->mode_ace = 1;
1438 		break;
1439 	case Opt_cifsacl:
1440 		ctx->cifs_acl = !result.negated;
1441 		break;
1442 	case Opt_acl:
1443 		ctx->no_psx_acl = result.negated;
1444 		break;
1445 	case Opt_locallease:
1446 		ctx->local_lease = 1;
1447 		break;
1448 	case Opt_sign:
1449 		ctx->sign = true;
1450 		break;
1451 	case Opt_ignore_signature:
1452 		ctx->sign = true;
1453 		ctx->ignore_signature = true;
1454 		break;
1455 	case Opt_seal:
1456 		/* we do not do the following in secFlags because seal
1457 		 * is a per tree connection (mount) not a per socket
1458 		 * or per-smb connection option in the protocol
1459 		 * vol->secFlg |= CIFSSEC_MUST_SEAL;
1460 		 */
1461 		ctx->seal = 1;
1462 		break;
1463 	case Opt_noac:
1464 		pr_warn("Mount option noac not supported. Instead set /proc/fs/cifs/LookupCacheEnabled to 0\n");
1465 		break;
1466 	case Opt_fsc:
1467 #ifndef CONFIG_CIFS_FSCACHE
1468 		cifs_errorf(fc, "FS-Cache support needs CONFIG_CIFS_FSCACHE kernel config option set\n");
1469 		goto cifs_parse_mount_err;
1470 #endif
1471 		ctx->fsc = true;
1472 		break;
1473 	case Opt_mfsymlinks:
1474 		ctx->mfsymlinks = true;
1475 		break;
1476 	case Opt_multiuser:
1477 		ctx->multiuser = true;
1478 		break;
1479 	case Opt_sloppy:
1480 		ctx->sloppy = true;
1481 		break;
1482 	case Opt_nosharesock:
1483 		ctx->nosharesock = true;
1484 		break;
1485 	case Opt_persistent:
1486 		if (result.negated) {
1487 			ctx->nopersistent = true;
1488 			if (ctx->persistent) {
1489 				cifs_errorf(fc, "persistenthandles mount options conflict\n");
1490 				goto cifs_parse_mount_err;
1491 			}
1492 		} else {
1493 			ctx->persistent = true;
1494 			if ((ctx->nopersistent) || (ctx->resilient)) {
1495 				cifs_errorf(fc, "persistenthandles mount options conflict\n");
1496 				goto cifs_parse_mount_err;
1497 			}
1498 		}
1499 		break;
1500 	case Opt_resilient:
1501 		if (result.negated) {
1502 			ctx->resilient = false; /* already the default */
1503 		} else {
1504 			ctx->resilient = true;
1505 			if (ctx->persistent) {
1506 				cifs_errorf(fc, "persistenthandles mount options conflict\n");
1507 				goto cifs_parse_mount_err;
1508 			}
1509 		}
1510 		break;
1511 	case Opt_tcp_nodelay:
1512 		/* tcp nodelay should not usually be needed since we CORK/UNCORK the socket */
1513 		if (result.negated)
1514 			ctx->sockopt_tcp_nodelay = false;
1515 		else
1516 			ctx->sockopt_tcp_nodelay = true;
1517 		break;
1518 	case Opt_domainauto:
1519 		ctx->domainauto = true;
1520 		break;
1521 	case Opt_rdma:
1522 		ctx->rdma = true;
1523 		break;
1524 	}
1525 	/* case Opt_ignore: - is ignored as expected ... */
1526 
1527 	return 0;
1528 
1529  cifs_parse_mount_err:
1530 	kfree_sensitive(ctx->password);
1531 	return -EINVAL;
1532 }
1533 
1534 int smb3_init_fs_context(struct fs_context *fc)
1535 {
1536 	struct smb3_fs_context *ctx;
1537 	char *nodename = utsname()->nodename;
1538 	int i;
1539 
1540 	ctx = kzalloc(sizeof(struct smb3_fs_context), GFP_KERNEL);
1541 	if (unlikely(!ctx))
1542 		return -ENOMEM;
1543 
1544 	strscpy(ctx->workstation_name, nodename, sizeof(ctx->workstation_name));
1545 
1546 	/*
1547 	 * does not have to be perfect mapping since field is
1548 	 * informational, only used for servers that do not support
1549 	 * port 445 and it can be overridden at mount time
1550 	 */
1551 	memset(ctx->source_rfc1001_name, 0x20, RFC1001_NAME_LEN);
1552 	for (i = 0; i < strnlen(nodename, RFC1001_NAME_LEN); i++)
1553 		ctx->source_rfc1001_name[i] = toupper(nodename[i]);
1554 
1555 	ctx->source_rfc1001_name[RFC1001_NAME_LEN] = 0;
1556 	/*
1557 	 * null target name indicates to use *SMBSERVR default called name
1558 	 *  if we end up sending RFC1001 session initialize
1559 	 */
1560 	ctx->target_rfc1001_name[0] = 0;
1561 	ctx->cred_uid = current_uid();
1562 	ctx->linux_uid = current_uid();
1563 	ctx->linux_gid = current_gid();
1564 	/* By default 4MB read ahead size, 1MB block size */
1565 	ctx->bsize = CIFS_DEFAULT_IOSIZE; /* can improve cp performance significantly */
1566 	ctx->rasize = 0; /* 0 = use default (ie negotiated rsize) for read ahead pages */
1567 
1568 	/*
1569 	 * default to SFM style remapping of seven reserved characters
1570 	 * unless user overrides it or we negotiate CIFS POSIX where
1571 	 * it is unnecessary.  Can not simultaneously use more than one mapping
1572 	 * since then readdir could list files that open could not open
1573 	 */
1574 	ctx->remap = true;
1575 
1576 	/* default to only allowing write access to owner of the mount */
1577 	ctx->dir_mode = ctx->file_mode = S_IRUGO | S_IXUGO | S_IWUSR;
1578 
1579 	/* ctx->retry default is 0 (i.e. "soft" limited retry not hard retry) */
1580 	/* default is always to request posix paths. */
1581 	ctx->posix_paths = 1;
1582 	/* default to using server inode numbers where available */
1583 	ctx->server_ino = 1;
1584 
1585 	/* default is to use strict cifs caching semantics */
1586 	ctx->strict_io = true;
1587 
1588 	ctx->acregmax = CIFS_DEF_ACTIMEO;
1589 	ctx->acdirmax = CIFS_DEF_ACTIMEO;
1590 	ctx->closetimeo = SMB3_DEF_DCLOSETIMEO;
1591 
1592 	/* Most clients set timeout to 0, allows server to use its default */
1593 	ctx->handle_timeout = 0; /* See MS-SMB2 spec section 2.2.14.2.12 */
1594 
1595 	/* offer SMB2.1 and later (SMB3 etc). Secure and widely accepted */
1596 	ctx->ops = &smb30_operations;
1597 	ctx->vals = &smbdefault_values;
1598 
1599 	ctx->echo_interval = SMB_ECHO_INTERVAL_DEFAULT;
1600 
1601 	/* default to no multichannel (single server connection) */
1602 	ctx->multichannel = false;
1603 	ctx->max_channels = 1;
1604 
1605 	ctx->backupuid_specified = false; /* no backup intent for a user */
1606 	ctx->backupgid_specified = false; /* no backup intent for a group */
1607 
1608 /*
1609  *	short int override_uid = -1;
1610  *	short int override_gid = -1;
1611  *	char *nodename = strdup(utsname()->nodename);
1612  *	struct sockaddr *dstaddr = (struct sockaddr *)&vol->dstaddr;
1613  */
1614 
1615 	fc->fs_private = ctx;
1616 	fc->ops = &smb3_fs_context_ops;
1617 	return 0;
1618 }
1619 
1620 void
1621 smb3_cleanup_fs_context_contents(struct smb3_fs_context *ctx)
1622 {
1623 	if (ctx == NULL)
1624 		return;
1625 
1626 	/*
1627 	 * Make sure this stays in sync with smb3_fs_context_dup()
1628 	 */
1629 	kfree(ctx->username);
1630 	ctx->username = NULL;
1631 	kfree_sensitive(ctx->password);
1632 	ctx->password = NULL;
1633 	kfree(ctx->server_hostname);
1634 	ctx->server_hostname = NULL;
1635 	kfree(ctx->UNC);
1636 	ctx->UNC = NULL;
1637 	kfree(ctx->source);
1638 	ctx->source = NULL;
1639 	kfree(ctx->domainname);
1640 	ctx->domainname = NULL;
1641 	kfree(ctx->nodename);
1642 	ctx->nodename = NULL;
1643 	kfree(ctx->iocharset);
1644 	ctx->iocharset = NULL;
1645 	kfree(ctx->prepath);
1646 	ctx->prepath = NULL;
1647 	kfree(ctx->leaf_fullpath);
1648 	ctx->leaf_fullpath = NULL;
1649 }
1650 
1651 void
1652 smb3_cleanup_fs_context(struct smb3_fs_context *ctx)
1653 {
1654 	if (!ctx)
1655 		return;
1656 	smb3_cleanup_fs_context_contents(ctx);
1657 	kfree(ctx);
1658 }
1659 
1660 void smb3_update_mnt_flags(struct cifs_sb_info *cifs_sb)
1661 {
1662 	struct smb3_fs_context *ctx = cifs_sb->ctx;
1663 
1664 	if (ctx->nodfs)
1665 		cifs_sb->mnt_cifs_flags |= CIFS_MOUNT_NO_DFS;
1666 	else
1667 		cifs_sb->mnt_cifs_flags &= ~CIFS_MOUNT_NO_DFS;
1668 
1669 	if (ctx->noperm)
1670 		cifs_sb->mnt_cifs_flags |= CIFS_MOUNT_NO_PERM;
1671 	else
1672 		cifs_sb->mnt_cifs_flags &= ~CIFS_MOUNT_NO_PERM;
1673 
1674 	if (ctx->setuids)
1675 		cifs_sb->mnt_cifs_flags |= CIFS_MOUNT_SET_UID;
1676 	else
1677 		cifs_sb->mnt_cifs_flags &= ~CIFS_MOUNT_SET_UID;
1678 
1679 	if (ctx->setuidfromacl)
1680 		cifs_sb->mnt_cifs_flags |= CIFS_MOUNT_UID_FROM_ACL;
1681 	else
1682 		cifs_sb->mnt_cifs_flags &= ~CIFS_MOUNT_UID_FROM_ACL;
1683 
1684 	if (ctx->server_ino)
1685 		cifs_sb->mnt_cifs_flags |= CIFS_MOUNT_SERVER_INUM;
1686 	else
1687 		cifs_sb->mnt_cifs_flags &= ~CIFS_MOUNT_SERVER_INUM;
1688 
1689 	if (ctx->remap)
1690 		cifs_sb->mnt_cifs_flags |= CIFS_MOUNT_MAP_SFM_CHR;
1691 	else
1692 		cifs_sb->mnt_cifs_flags &= ~CIFS_MOUNT_MAP_SFM_CHR;
1693 
1694 	if (ctx->sfu_remap)
1695 		cifs_sb->mnt_cifs_flags |= CIFS_MOUNT_MAP_SPECIAL_CHR;
1696 	else
1697 		cifs_sb->mnt_cifs_flags &= ~CIFS_MOUNT_MAP_SPECIAL_CHR;
1698 
1699 	if (ctx->no_xattr)
1700 		cifs_sb->mnt_cifs_flags |= CIFS_MOUNT_NO_XATTR;
1701 	else
1702 		cifs_sb->mnt_cifs_flags &= ~CIFS_MOUNT_NO_XATTR;
1703 
1704 	if (ctx->sfu_emul)
1705 		cifs_sb->mnt_cifs_flags |= CIFS_MOUNT_UNX_EMUL;
1706 	else
1707 		cifs_sb->mnt_cifs_flags &= ~CIFS_MOUNT_UNX_EMUL;
1708 
1709 	if (ctx->nobrl)
1710 		cifs_sb->mnt_cifs_flags |= CIFS_MOUNT_NO_BRL;
1711 	else
1712 		cifs_sb->mnt_cifs_flags &= ~CIFS_MOUNT_NO_BRL;
1713 
1714 	if (ctx->nohandlecache)
1715 		cifs_sb->mnt_cifs_flags |= CIFS_MOUNT_NO_HANDLE_CACHE;
1716 	else
1717 		cifs_sb->mnt_cifs_flags &= ~CIFS_MOUNT_NO_HANDLE_CACHE;
1718 
1719 	if (ctx->nostrictsync)
1720 		cifs_sb->mnt_cifs_flags |= CIFS_MOUNT_NOSSYNC;
1721 	else
1722 		cifs_sb->mnt_cifs_flags &= ~CIFS_MOUNT_NOSSYNC;
1723 
1724 	if (ctx->mand_lock)
1725 		cifs_sb->mnt_cifs_flags |= CIFS_MOUNT_NOPOSIXBRL;
1726 	else
1727 		cifs_sb->mnt_cifs_flags &= ~CIFS_MOUNT_NOPOSIXBRL;
1728 
1729 	if (ctx->rwpidforward)
1730 		cifs_sb->mnt_cifs_flags |= CIFS_MOUNT_RWPIDFORWARD;
1731 	else
1732 		cifs_sb->mnt_cifs_flags &= ~CIFS_MOUNT_RWPIDFORWARD;
1733 
1734 	if (ctx->mode_ace)
1735 		cifs_sb->mnt_cifs_flags |= CIFS_MOUNT_MODE_FROM_SID;
1736 	else
1737 		cifs_sb->mnt_cifs_flags &= ~CIFS_MOUNT_MODE_FROM_SID;
1738 
1739 	if (ctx->cifs_acl)
1740 		cifs_sb->mnt_cifs_flags |= CIFS_MOUNT_CIFS_ACL;
1741 	else
1742 		cifs_sb->mnt_cifs_flags &= ~CIFS_MOUNT_CIFS_ACL;
1743 
1744 	if (ctx->backupuid_specified)
1745 		cifs_sb->mnt_cifs_flags |= CIFS_MOUNT_CIFS_BACKUPUID;
1746 	else
1747 		cifs_sb->mnt_cifs_flags &= ~CIFS_MOUNT_CIFS_BACKUPUID;
1748 
1749 	if (ctx->backupgid_specified)
1750 		cifs_sb->mnt_cifs_flags |= CIFS_MOUNT_CIFS_BACKUPGID;
1751 	else
1752 		cifs_sb->mnt_cifs_flags &= ~CIFS_MOUNT_CIFS_BACKUPGID;
1753 
1754 	if (ctx->override_uid)
1755 		cifs_sb->mnt_cifs_flags |= CIFS_MOUNT_OVERR_UID;
1756 	else
1757 		cifs_sb->mnt_cifs_flags &= ~CIFS_MOUNT_OVERR_UID;
1758 
1759 	if (ctx->override_gid)
1760 		cifs_sb->mnt_cifs_flags |= CIFS_MOUNT_OVERR_GID;
1761 	else
1762 		cifs_sb->mnt_cifs_flags &= ~CIFS_MOUNT_OVERR_GID;
1763 
1764 	if (ctx->dynperm)
1765 		cifs_sb->mnt_cifs_flags |= CIFS_MOUNT_DYNPERM;
1766 	else
1767 		cifs_sb->mnt_cifs_flags &= ~CIFS_MOUNT_DYNPERM;
1768 
1769 	if (ctx->fsc)
1770 		cifs_sb->mnt_cifs_flags |= CIFS_MOUNT_FSCACHE;
1771 	else
1772 		cifs_sb->mnt_cifs_flags &= ~CIFS_MOUNT_FSCACHE;
1773 
1774 	if (ctx->multiuser)
1775 		cifs_sb->mnt_cifs_flags |= (CIFS_MOUNT_MULTIUSER |
1776 					    CIFS_MOUNT_NO_PERM);
1777 	else
1778 		cifs_sb->mnt_cifs_flags &= ~CIFS_MOUNT_MULTIUSER;
1779 
1780 
1781 	if (ctx->strict_io)
1782 		cifs_sb->mnt_cifs_flags |= CIFS_MOUNT_STRICT_IO;
1783 	else
1784 		cifs_sb->mnt_cifs_flags &= ~CIFS_MOUNT_STRICT_IO;
1785 
1786 	if (ctx->direct_io)
1787 		cifs_sb->mnt_cifs_flags |= CIFS_MOUNT_DIRECT_IO;
1788 	else
1789 		cifs_sb->mnt_cifs_flags &= ~CIFS_MOUNT_DIRECT_IO;
1790 
1791 	if (ctx->mfsymlinks)
1792 		cifs_sb->mnt_cifs_flags |= CIFS_MOUNT_MF_SYMLINKS;
1793 	else
1794 		cifs_sb->mnt_cifs_flags &= ~CIFS_MOUNT_MF_SYMLINKS;
1795 	if (ctx->mfsymlinks) {
1796 		if (ctx->sfu_emul) {
1797 			/*
1798 			 * Our SFU ("Services for Unix" emulation does not allow
1799 			 * creating symlinks but does allow reading existing SFU
1800 			 * symlinks (it does allow both creating and reading SFU
1801 			 * style mknod and FIFOs though). When "mfsymlinks" and
1802 			 * "sfu" are both enabled at the same time, it allows
1803 			 * reading both types of symlinks, but will only create
1804 			 * them with mfsymlinks format. This allows better
1805 			 * Apple compatibility (probably better for Samba too)
1806 			 * while still recognizing old Windows style symlinks.
1807 			 */
1808 			cifs_dbg(VFS, "mount options mfsymlinks and sfu both enabled\n");
1809 		}
1810 	}
1811 	cifs_sb->mnt_cifs_flags &= ~CIFS_MOUNT_SHUTDOWN;
1812 
1813 	return;
1814 }
1815