xref: /linux/fs/smb/server/misc.c (revision 995832b2cebe6969d1b42635db698803ee31294d)
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 	bool has_stream_type = false;
125 
126 	*stream_name = NULL;
127 	s_name = filename;
128 	filename = strsep(&s_name, ":");
129 	ksmbd_debug(SMB, "filename : %s, streams : %s\n", filename, s_name);
130 	if (strchr(s_name, ':')) {
131 		stream_type = s_name;
132 		s_name = strsep(&stream_type, ":");
133 
134 		rc = ksmbd_validate_stream_name(s_name);
135 		if (rc < 0) {
136 			rc = -ENOENT;
137 			goto out;
138 		}
139 
140 		ksmbd_debug(SMB, "stream name : %s, stream type : %s\n", s_name,
141 			    stream_type);
142 		if (!strncasecmp("$data", stream_type, 5)) {
143 			*s_type = DATA_STREAM;
144 			has_stream_type = true;
145 		} else if (!strncasecmp("$index_allocation", stream_type, 17)) {
146 			*s_type = DIR_STREAM;
147 			has_stream_type = true;
148 		} else {
149 			rc = -ENOENT;
150 		}
151 	}
152 
153 	if (has_stream_type && !s_name[0] && *s_type == DATA_STREAM)
154 		goto out;
155 
156 	*stream_name = s_name;
157 out:
158 	return rc;
159 }
160 
161 /**
162  * convert_to_nt_pathname() - extract and return windows path string
163  *      whose share directory prefix was removed from file path
164  * @share: ksmbd_share_config pointer
165  * @path: path to report
166  *
167  * Return : windows path string or error
168  */
169 
170 char *convert_to_nt_pathname(struct ksmbd_share_config *share,
171 			     const struct path *path)
172 {
173 	char *pathname, *ab_pathname, *nt_pathname;
174 	int share_path_len = share->path_sz;
175 	size_t ab_pathname_len;
176 	int prefix;
177 
178 	pathname = kmalloc(PATH_MAX, KSMBD_DEFAULT_GFP);
179 	if (!pathname)
180 		return ERR_PTR(-EACCES);
181 
182 	ab_pathname = d_path(path, pathname, PATH_MAX);
183 	if (IS_ERR(ab_pathname)) {
184 		nt_pathname = ERR_PTR(-EACCES);
185 		goto free_pathname;
186 	}
187 
188 	if (strncmp(ab_pathname, share->path, share_path_len)) {
189 		nt_pathname = ERR_PTR(-EACCES);
190 		goto free_pathname;
191 	}
192 
193 	ab_pathname_len = strlen(&ab_pathname[share_path_len]);
194 	prefix = ab_pathname[share_path_len] == '\0' ? 1 : 0;
195 	nt_pathname = kmalloc(prefix + ab_pathname_len + 1, KSMBD_DEFAULT_GFP);
196 	if (!nt_pathname) {
197 		nt_pathname = ERR_PTR(-ENOMEM);
198 		goto free_pathname;
199 	}
200 
201 	if (prefix)
202 		*nt_pathname = '/';
203 	memcpy(nt_pathname + prefix, &ab_pathname[share_path_len],
204 	       ab_pathname_len + 1);
205 
206 	ksmbd_conv_path_to_windows(nt_pathname);
207 
208 free_pathname:
209 	kfree(pathname);
210 	return nt_pathname;
211 }
212 
213 int get_nlink(struct kstat *st)
214 {
215 	int nlink;
216 
217 	nlink = st->nlink;
218 	if (S_ISDIR(st->mode))
219 		nlink--;
220 
221 	return nlink;
222 }
223 
224 void ksmbd_conv_path_to_unix(char *path)
225 {
226 	strreplace(path, '\\', '/');
227 }
228 
229 void ksmbd_strip_last_slash(char *path)
230 {
231 	int len = strlen(path);
232 
233 	while (len && path[len - 1] == '/') {
234 		path[len - 1] = '\0';
235 		len--;
236 	}
237 }
238 
239 void ksmbd_conv_path_to_windows(char *path)
240 {
241 	strreplace(path, '/', '\\');
242 }
243 
244 char *ksmbd_casefold_sharename(struct unicode_map *um, const char *name)
245 {
246 	char *cf_name;
247 	int cf_len;
248 
249 	cf_name = kzalloc(KSMBD_REQ_MAX_SHARE_NAME, KSMBD_DEFAULT_GFP);
250 	if (!cf_name)
251 		return ERR_PTR(-ENOMEM);
252 
253 	if (IS_ENABLED(CONFIG_UNICODE) && um) {
254 		const struct qstr q_name = {.name = name, .len = strlen(name)};
255 
256 		cf_len = utf8_casefold(um, &q_name, cf_name,
257 				       KSMBD_REQ_MAX_SHARE_NAME);
258 		if (cf_len < 0)
259 			goto out_ascii;
260 
261 		return cf_name;
262 	}
263 
264 out_ascii:
265 	cf_len = strscpy(cf_name, name, KSMBD_REQ_MAX_SHARE_NAME);
266 	if (cf_len < 0) {
267 		kfree(cf_name);
268 		return ERR_PTR(-E2BIG);
269 	}
270 
271 	for (; *cf_name; ++cf_name)
272 		*cf_name = isascii(*cf_name) ? tolower(*cf_name) : *cf_name;
273 	return cf_name - cf_len;
274 }
275 
276 /**
277  * ksmbd_extract_sharename() - get share name from tree connect request
278  * @um: pointer to a unicode_map structure for character encoding handling
279  * @treename:	buffer containing tree name and share name
280  *
281  * Return:      share name on success, otherwise error
282  */
283 char *ksmbd_extract_sharename(struct unicode_map *um, const char *treename)
284 {
285 	const char *name = treename, *pos = strrchr(name, '\\');
286 
287 	if (pos)
288 		name = (pos + 1);
289 
290 	/* caller has to free the memory */
291 	return ksmbd_casefold_sharename(um, name);
292 }
293 
294 char *ksmbd_convert_dir_info_name(struct ksmbd_dir_info *d_info,
295 				  const struct nls_table *local_nls,
296 				  int *conv_len)
297 {
298 	char *conv;
299 	int  sz = min(4 * d_info->name_len, PATH_MAX);
300 
301 	if (!sz)
302 		return NULL;
303 
304 	conv = kmalloc(sz, KSMBD_DEFAULT_GFP);
305 	if (!conv)
306 		return NULL;
307 
308 	/* XXX */
309 	*conv_len = smbConvertToUTF16((__le16 *)conv, d_info->name,
310 				      d_info->name_len, local_nls, 0);
311 	*conv_len *= 2;
312 
313 	/* We allocate buffer twice bigger than needed. */
314 	conv[*conv_len] = 0x00;
315 	conv[*conv_len + 1] = 0x00;
316 	return conv;
317 }
318 
319 /*
320  * Convert the NT UTC (based 1601-01-01, in hundred nanosecond units)
321  * into Unix UTC (based 1970-01-01, in seconds).
322  */
323 struct timespec64 ksmbd_NTtimeToUnix(__le64 ntutc)
324 {
325 	struct timespec64 ts;
326 
327 	/* Subtract the NTFS time offset, then convert to 1s intervals. */
328 	s64 t = le64_to_cpu(ntutc) - NTFS_TIME_OFFSET;
329 	u64 abs_t;
330 
331 	/*
332 	 * Unfortunately can not use normal 64 bit division on 32 bit arch, but
333 	 * the alternative, do_div, does not work with negative numbers so have
334 	 * to special case them
335 	 */
336 	if (t < 0) {
337 		abs_t = -t;
338 		ts.tv_nsec = do_div(abs_t, 10000000) * 100;
339 		ts.tv_nsec = -ts.tv_nsec;
340 		ts.tv_sec = -abs_t;
341 	} else {
342 		abs_t = t;
343 		ts.tv_nsec = do_div(abs_t, 10000000) * 100;
344 		ts.tv_sec = abs_t;
345 	}
346 
347 	return ts;
348 }
349 
350 /* Convert the Unix UTC into NT UTC. */
351 inline u64 ksmbd_UnixTimeToNT(struct timespec64 t)
352 {
353 	/* Convert to 100ns intervals and then add the NTFS time offset. */
354 	return (u64)t.tv_sec * 10000000 + t.tv_nsec / 100 + NTFS_TIME_OFFSET;
355 }
356 
357 inline long long ksmbd_systime(void)
358 {
359 	struct timespec64	ts;
360 
361 	ktime_get_real_ts64(&ts);
362 	return ksmbd_UnixTimeToNT(ts);
363 }
364