xref: /linux/fs/smb/server/misc.c (revision 869737543b39a145809c41a7253c6ee777e22729)
1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3  *   Copyright (C) 2016 Namjae Jeon <linkinjeon@kernel.org>
4  *   Copyright (C) 2018 Samsung Electronics Co., Ltd.
5  */
6 
7 #include <linux/kernel.h>
8 #include <linux/xattr.h>
9 #include <linux/fs.h>
10 #include <linux/unicode.h>
11 
12 #include "misc.h"
13 #include "smb_common.h"
14 #include "connection.h"
15 #include "vfs.h"
16 
17 #include "mgmt/share_config.h"
18 
19 /**
20  * match_pattern() - compare a string with a pattern which might include
21  * wildcard '*' and '?'
22  * TODO : implement consideration about DOS_DOT, DOS_QM and DOS_STAR
23  *
24  * @str:	string to compare with a pattern
25  * @len:	string length
26  * @pattern:	pattern string which might include wildcard '*' and '?'
27  *
28  * Return:	0 if pattern matched with the string, otherwise non zero value
29  */
30 int match_pattern(const char *str, size_t len, const char *pattern)
31 {
32 	const char *s = str;
33 	const char *p = pattern;
34 	bool star = false;
35 
36 	while (*s && len) {
37 		switch (*p) {
38 		case '?':
39 			s++;
40 			len--;
41 			p++;
42 			break;
43 		case '*':
44 			star = true;
45 			str = s;
46 			if (!*++p)
47 				return true;
48 			pattern = p;
49 			break;
50 		default:
51 			if (tolower(*s) == tolower(*p)) {
52 				s++;
53 				len--;
54 				p++;
55 			} else {
56 				if (!star)
57 					return false;
58 				str++;
59 				s = str;
60 				p = pattern;
61 			}
62 			break;
63 		}
64 	}
65 
66 	if (*p == '*')
67 		++p;
68 	return !*p;
69 }
70 
71 /*
72  * is_char_allowed() - check for valid character
73  * @ch:		input character to be checked
74  *
75  * Return:	1 if char is allowed, otherwise 0
76  */
77 static inline int is_char_allowed(char ch)
78 {
79 	/* check for control chars, wildcards etc. */
80 	if (!(ch & 0x80) &&
81 	    (ch <= 0x1f ||
82 	     ch == '?' || ch == '"' || ch == '<' ||
83 	     ch == '>' || ch == '|' || ch == '*'))
84 		return 0;
85 
86 	return 1;
87 }
88 
89 int ksmbd_validate_filename(char *filename)
90 {
91 	while (*filename) {
92 		char c = *filename;
93 
94 		filename++;
95 		if (!is_char_allowed(c)) {
96 			ksmbd_debug(VFS, "File name validation failed: 0x%x\n", c);
97 			return -ENOENT;
98 		}
99 	}
100 
101 	return 0;
102 }
103 
104 static int ksmbd_validate_stream_name(char *stream_name)
105 {
106 	while (*stream_name) {
107 		char c = *stream_name;
108 
109 		stream_name++;
110 		if (c == '/' || c == ':' || c == '\\') {
111 			pr_err("Stream name validation failed: %c\n", c);
112 			return -ENOENT;
113 		}
114 	}
115 
116 	return 0;
117 }
118 
119 int parse_stream_name(char *filename, char **stream_name, int *s_type)
120 {
121 	char *stream_type;
122 	char *s_name;
123 	int rc = 0;
124 
125 	s_name = filename;
126 	filename = strsep(&s_name, ":");
127 	ksmbd_debug(SMB, "filename : %s, streams : %s\n", filename, s_name);
128 	if (strchr(s_name, ':')) {
129 		stream_type = s_name;
130 		s_name = strsep(&stream_type, ":");
131 
132 		rc = ksmbd_validate_stream_name(s_name);
133 		if (rc < 0) {
134 			rc = -ENOENT;
135 			goto out;
136 		}
137 
138 		ksmbd_debug(SMB, "stream name : %s, stream type : %s\n", s_name,
139 			    stream_type);
140 		if (!strncasecmp("$data", stream_type, 5))
141 			*s_type = DATA_STREAM;
142 		else if (!strncasecmp("$index_allocation", stream_type, 17))
143 			*s_type = DIR_STREAM;
144 		else
145 			rc = -ENOENT;
146 	}
147 
148 	*stream_name = s_name;
149 out:
150 	return rc;
151 }
152 
153 /**
154  * convert_to_nt_pathname() - extract and return windows path string
155  *      whose share directory prefix was removed from file path
156  * @share: ksmbd_share_config pointer
157  * @path: path to report
158  *
159  * Return : windows path string or error
160  */
161 
162 char *convert_to_nt_pathname(struct ksmbd_share_config *share,
163 			     const struct path *path)
164 {
165 	char *pathname, *ab_pathname, *nt_pathname;
166 	int share_path_len = share->path_sz;
167 	size_t ab_pathname_len;
168 	int prefix;
169 
170 	pathname = kmalloc(PATH_MAX, KSMBD_DEFAULT_GFP);
171 	if (!pathname)
172 		return ERR_PTR(-EACCES);
173 
174 	ab_pathname = d_path(path, pathname, PATH_MAX);
175 	if (IS_ERR(ab_pathname)) {
176 		nt_pathname = ERR_PTR(-EACCES);
177 		goto free_pathname;
178 	}
179 
180 	if (strncmp(ab_pathname, share->path, share_path_len)) {
181 		nt_pathname = ERR_PTR(-EACCES);
182 		goto free_pathname;
183 	}
184 
185 	ab_pathname_len = strlen(&ab_pathname[share_path_len]);
186 	prefix = ab_pathname[share_path_len] == '\0' ? 1 : 0;
187 	nt_pathname = kmalloc(prefix + ab_pathname_len + 1, KSMBD_DEFAULT_GFP);
188 	if (!nt_pathname) {
189 		nt_pathname = ERR_PTR(-ENOMEM);
190 		goto free_pathname;
191 	}
192 
193 	if (prefix)
194 		*nt_pathname = '/';
195 	memcpy(nt_pathname + prefix, &ab_pathname[share_path_len],
196 	       ab_pathname_len + 1);
197 
198 	ksmbd_conv_path_to_windows(nt_pathname);
199 
200 free_pathname:
201 	kfree(pathname);
202 	return nt_pathname;
203 }
204 
205 int get_nlink(struct kstat *st)
206 {
207 	int nlink;
208 
209 	nlink = st->nlink;
210 	if (S_ISDIR(st->mode))
211 		nlink--;
212 
213 	return nlink;
214 }
215 
216 void ksmbd_conv_path_to_unix(char *path)
217 {
218 	strreplace(path, '\\', '/');
219 }
220 
221 void ksmbd_strip_last_slash(char *path)
222 {
223 	int len = strlen(path);
224 
225 	while (len && path[len - 1] == '/') {
226 		path[len - 1] = '\0';
227 		len--;
228 	}
229 }
230 
231 void ksmbd_conv_path_to_windows(char *path)
232 {
233 	strreplace(path, '/', '\\');
234 }
235 
236 char *ksmbd_casefold_sharename(struct unicode_map *um, const char *name)
237 {
238 	char *cf_name;
239 	int cf_len;
240 
241 	cf_name = kzalloc(KSMBD_REQ_MAX_SHARE_NAME, KSMBD_DEFAULT_GFP);
242 	if (!cf_name)
243 		return ERR_PTR(-ENOMEM);
244 
245 	if (IS_ENABLED(CONFIG_UNICODE) && um) {
246 		const struct qstr q_name = {.name = name, .len = strlen(name)};
247 
248 		cf_len = utf8_casefold(um, &q_name, cf_name,
249 				       KSMBD_REQ_MAX_SHARE_NAME);
250 		if (cf_len < 0)
251 			goto out_ascii;
252 
253 		return cf_name;
254 	}
255 
256 out_ascii:
257 	cf_len = strscpy(cf_name, name, KSMBD_REQ_MAX_SHARE_NAME);
258 	if (cf_len < 0) {
259 		kfree(cf_name);
260 		return ERR_PTR(-E2BIG);
261 	}
262 
263 	for (; *cf_name; ++cf_name)
264 		*cf_name = isascii(*cf_name) ? tolower(*cf_name) : *cf_name;
265 	return cf_name - cf_len;
266 }
267 
268 /**
269  * ksmbd_extract_sharename() - get share name from tree connect request
270  * @um: pointer to a unicode_map structure for character encoding handling
271  * @treename:	buffer containing tree name and share name
272  *
273  * Return:      share name on success, otherwise error
274  */
275 char *ksmbd_extract_sharename(struct unicode_map *um, const char *treename)
276 {
277 	const char *name = treename, *pos = strrchr(name, '\\');
278 
279 	if (pos)
280 		name = (pos + 1);
281 
282 	/* caller has to free the memory */
283 	return ksmbd_casefold_sharename(um, name);
284 }
285 
286 /**
287  * convert_to_unix_name() - convert windows name to unix format
288  * @share:	ksmbd_share_config pointer
289  * @name:	file name that is relative to share
290  *
291  * Return:	converted name on success, otherwise NULL
292  */
293 char *convert_to_unix_name(struct ksmbd_share_config *share, const char *name)
294 {
295 	int no_slash = 0, name_len, path_len;
296 	char *new_name;
297 
298 	if (name[0] == '/')
299 		name++;
300 
301 	path_len = share->path_sz;
302 	name_len = strlen(name);
303 	new_name = kmalloc(path_len + name_len + 2, KSMBD_DEFAULT_GFP);
304 	if (!new_name)
305 		return new_name;
306 
307 	memcpy(new_name, share->path, path_len);
308 	if (new_name[path_len - 1] != '/') {
309 		new_name[path_len] = '/';
310 		no_slash = 1;
311 	}
312 
313 	memcpy(new_name + path_len + no_slash, name, name_len);
314 	path_len += name_len + no_slash;
315 	new_name[path_len] = 0x00;
316 	return new_name;
317 }
318 
319 char *ksmbd_convert_dir_info_name(struct ksmbd_dir_info *d_info,
320 				  const struct nls_table *local_nls,
321 				  int *conv_len)
322 {
323 	char *conv;
324 	int  sz = min(4 * d_info->name_len, PATH_MAX);
325 
326 	if (!sz)
327 		return NULL;
328 
329 	conv = kmalloc(sz, KSMBD_DEFAULT_GFP);
330 	if (!conv)
331 		return NULL;
332 
333 	/* XXX */
334 	*conv_len = smbConvertToUTF16((__le16 *)conv, d_info->name,
335 				      d_info->name_len, local_nls, 0);
336 	*conv_len *= 2;
337 
338 	/* We allocate buffer twice bigger than needed. */
339 	conv[*conv_len] = 0x00;
340 	conv[*conv_len + 1] = 0x00;
341 	return conv;
342 }
343 
344 /*
345  * Convert the NT UTC (based 1601-01-01, in hundred nanosecond units)
346  * into Unix UTC (based 1970-01-01, in seconds).
347  */
348 struct timespec64 ksmbd_NTtimeToUnix(__le64 ntutc)
349 {
350 	struct timespec64 ts;
351 
352 	/* Subtract the NTFS time offset, then convert to 1s intervals. */
353 	s64 t = le64_to_cpu(ntutc) - NTFS_TIME_OFFSET;
354 	u64 abs_t;
355 
356 	/*
357 	 * Unfortunately can not use normal 64 bit division on 32 bit arch, but
358 	 * the alternative, do_div, does not work with negative numbers so have
359 	 * to special case them
360 	 */
361 	if (t < 0) {
362 		abs_t = -t;
363 		ts.tv_nsec = do_div(abs_t, 10000000) * 100;
364 		ts.tv_nsec = -ts.tv_nsec;
365 		ts.tv_sec = -abs_t;
366 	} else {
367 		abs_t = t;
368 		ts.tv_nsec = do_div(abs_t, 10000000) * 100;
369 		ts.tv_sec = abs_t;
370 	}
371 
372 	return ts;
373 }
374 
375 /* Convert the Unix UTC into NT UTC. */
376 inline u64 ksmbd_UnixTimeToNT(struct timespec64 t)
377 {
378 	/* Convert to 100ns intervals and then add the NTFS time offset. */
379 	return (u64)t.tv_sec * 10000000 + t.tv_nsec / 100 + NTFS_TIME_OFFSET;
380 }
381 
382 inline long long ksmbd_systime(void)
383 {
384 	struct timespec64	ts;
385 
386 	ktime_get_real_ts64(&ts);
387 	return ksmbd_UnixTimeToNT(ts);
388 }
389