1 /*
2 * fs/cifs/cifs_unicode.c
3 *
4 * Copyright (c) International Business Machines Corp., 2000,2009
5 * Modified by Steve French (sfrench@us.ibm.com)
6 *
7 * This program is free software; you can redistribute it and/or modify
8 * it under the terms of the GNU General Public License as published by
9 * the Free Software Foundation; either version 2 of the License, or
10 * (at your option) any later version.
11 *
12 * This program is distributed in the hope that it will be useful,
13 * but WITHOUT ANY WARRANTY; without even the implied warranty of
14 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See
15 * the GNU General Public License for more details.
16 *
17 * You should have received a copy of the GNU General Public License
18 * along with this program; if not, write to the Free Software
19 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
20 */
21 #include <linux/fs.h>
22 #include <linux/slab.h>
23 #include "cifs_fs_sb.h"
24 #include "cifs_unicode.h"
25 #include "cifs_uniupr.h"
26 #include "cifspdu.h"
27 #include "cifsglob.h"
28 #include "cifs_debug.h"
29
cifs_remap(struct cifs_sb_info * cifs_sb)30 int cifs_remap(struct cifs_sb_info *cifs_sb)
31 {
32 int map_type;
33
34 if (cifs_sb->mnt_cifs_flags & CIFS_MOUNT_MAP_SFM_CHR)
35 map_type = SFM_MAP_UNI_RSVD;
36 else if (cifs_sb->mnt_cifs_flags & CIFS_MOUNT_MAP_SPECIAL_CHR)
37 map_type = SFU_MAP_UNI_RSVD;
38 else
39 map_type = NO_MAP_UNI_RSVD;
40
41 return map_type;
42 }
43
44 /* Convert character using the SFU - "Services for Unix" remapping range */
45 static bool
convert_sfu_char(const __u16 src_char,char * target)46 convert_sfu_char(const __u16 src_char, char *target)
47 {
48 /*
49 * BB: Cannot handle remapping UNI_SLASH until all the calls to
50 * build_path_from_dentry are modified, as they use slash as
51 * separator.
52 */
53 switch (src_char) {
54 case UNI_COLON:
55 *target = ':';
56 break;
57 case UNI_ASTERISK:
58 *target = '*';
59 break;
60 case UNI_QUESTION:
61 *target = '?';
62 break;
63 case UNI_PIPE:
64 *target = '|';
65 break;
66 case UNI_GRTRTHAN:
67 *target = '>';
68 break;
69 case UNI_LESSTHAN:
70 *target = '<';
71 break;
72 default:
73 return false;
74 }
75 return true;
76 }
77
78 /* Convert character using the SFM - "Services for Mac" remapping range */
79 static bool
convert_sfm_char(const __u16 src_char,char * target)80 convert_sfm_char(const __u16 src_char, char *target)
81 {
82 switch (src_char) {
83 case SFM_COLON:
84 *target = ':';
85 break;
86 case SFM_ASTERISK:
87 *target = '*';
88 break;
89 case SFM_QUESTION:
90 *target = '?';
91 break;
92 case SFM_PIPE:
93 *target = '|';
94 break;
95 case SFM_GRTRTHAN:
96 *target = '>';
97 break;
98 case SFM_LESSTHAN:
99 *target = '<';
100 break;
101 case SFM_SLASH:
102 *target = '\\';
103 break;
104 default:
105 return false;
106 }
107 return true;
108 }
109
110
111 /*
112 * cifs_mapchar - convert a host-endian char to proper char in codepage
113 * @target - where converted character should be copied
114 * @src_char - 2 byte host-endian source character
115 * @cp - codepage to which character should be converted
116 * @map_type - How should the 7 NTFS/SMB reserved characters be mapped to UCS2?
117 *
118 * This function handles the conversion of a single character. It is the
119 * responsibility of the caller to ensure that the target buffer is large
120 * enough to hold the result of the conversion (at least NLS_MAX_CHARSET_SIZE).
121 */
122 static int
cifs_mapchar(char * target,const __u16 * from,const struct nls_table * cp,int maptype)123 cifs_mapchar(char *target, const __u16 *from, const struct nls_table *cp,
124 int maptype)
125 {
126 int len = 1;
127 __u16 src_char;
128
129 src_char = *from;
130
131 if ((maptype == SFM_MAP_UNI_RSVD) && convert_sfm_char(src_char, target))
132 return len;
133 else if ((maptype == SFU_MAP_UNI_RSVD) &&
134 convert_sfu_char(src_char, target))
135 return len;
136
137 /* if character not one of seven in special remap set */
138 len = cp->uni2char(src_char, target, NLS_MAX_CHARSET_SIZE);
139 if (len <= 0)
140 goto surrogate_pair;
141
142 return len;
143
144 surrogate_pair:
145 /* convert SURROGATE_PAIR and IVS */
146 if (strcmp(cp->charset, "utf8"))
147 goto unknown;
148 len = utf16s_to_utf8s(from, 3, UTF16_LITTLE_ENDIAN, target, 6);
149 if (len <= 0)
150 goto unknown;
151 return len;
152
153 unknown:
154 *target = '?';
155 len = 1;
156 return len;
157 }
158
159 /*
160 * cifs_from_utf16 - convert utf16le string to local charset
161 * @to - destination buffer
162 * @from - source buffer
163 * @tolen - destination buffer size (in bytes)
164 * @fromlen - source buffer size (in bytes)
165 * @codepage - codepage to which characters should be converted
166 * @mapchar - should characters be remapped according to the mapchars option?
167 *
168 * Convert a little-endian utf16le string (as sent by the server) to a string
169 * in the provided codepage. The tolen and fromlen parameters are to ensure
170 * that the code doesn't walk off of the end of the buffer (which is always
171 * a danger if the alignment of the source buffer is off). The destination
172 * string is always properly null terminated and fits in the destination
173 * buffer. Returns the length of the destination string in bytes (including
174 * null terminator).
175 *
176 * Note that some windows versions actually send multiword UTF-16 characters
177 * instead of straight UTF16-2. The linux nls routines however aren't able to
178 * deal with those characters properly. In the event that we get some of
179 * those characters, they won't be translated properly.
180 */
181 int
cifs_from_utf16(char * to,const __le16 * from,int tolen,int fromlen,const struct nls_table * codepage,int map_type)182 cifs_from_utf16(char *to, const __le16 *from, int tolen, int fromlen,
183 const struct nls_table *codepage, int map_type)
184 {
185 int i, charlen, safelen;
186 int outlen = 0;
187 int nullsize = nls_nullsize(codepage);
188 int fromwords = fromlen / 2;
189 char tmp[NLS_MAX_CHARSET_SIZE];
190 __u16 ftmp[3]; /* ftmp[3] = 3array x 2bytes = 6bytes UTF-16 */
191
192 /*
193 * because the chars can be of varying widths, we need to take care
194 * not to overflow the destination buffer when we get close to the
195 * end of it. Until we get to this offset, we don't need to check
196 * for overflow however.
197 */
198 safelen = tolen - (NLS_MAX_CHARSET_SIZE + nullsize);
199
200 for (i = 0; i < fromwords; i++) {
201 ftmp[0] = get_unaligned_le16(&from[i]);
202 if (ftmp[0] == 0)
203 break;
204 if (i + 1 < fromwords)
205 ftmp[1] = get_unaligned_le16(&from[i + 1]);
206 else
207 ftmp[1] = 0;
208 if (i + 2 < fromwords)
209 ftmp[2] = get_unaligned_le16(&from[i + 2]);
210 else
211 ftmp[2] = 0;
212
213 /*
214 * check to see if converting this character might make the
215 * conversion bleed into the null terminator
216 */
217 if (outlen >= safelen) {
218 charlen = cifs_mapchar(tmp, ftmp, codepage, map_type);
219 if ((outlen + charlen) > (tolen - nullsize))
220 break;
221 }
222
223 /* put converted char into 'to' buffer */
224 charlen = cifs_mapchar(&to[outlen], ftmp, codepage, map_type);
225 outlen += charlen;
226
227 /* charlen (=bytes of UTF-8 for 1 character)
228 * 4bytes UTF-8(surrogate pair) is charlen=4
229 * (4bytes UTF-16 code)
230 * 7-8bytes UTF-8(IVS) is charlen=3+4 or 4+4
231 * (2 UTF-8 pairs divided to 2 UTF-16 pairs) */
232 if (charlen == 4)
233 i++;
234 else if (charlen >= 5)
235 /* 5-6bytes UTF-8 */
236 i += 2;
237 }
238
239 /* properly null-terminate string */
240 for (i = 0; i < nullsize; i++)
241 to[outlen++] = 0;
242
243 return outlen;
244 }
245
246 /*
247 * NAME: cifs_strtoUTF16()
248 *
249 * FUNCTION: Convert character string to unicode string
250 *
251 */
252 int
cifs_strtoUTF16(__le16 * to,const char * from,int len,const struct nls_table * codepage)253 cifs_strtoUTF16(__le16 *to, const char *from, int len,
254 const struct nls_table *codepage)
255 {
256 int charlen;
257 int i;
258 wchar_t wchar_to; /* needed to quiet sparse */
259
260 /* special case for utf8 to handle no plane0 chars */
261 if (!strcmp(codepage->charset, "utf8")) {
262 /*
263 * convert utf8 -> utf16, we assume we have enough space
264 * as caller should have assumed conversion does not overflow
265 * in destination len is length in wchar_t units (16bits)
266 */
267 i = utf8s_to_utf16s(from, len, UTF16_LITTLE_ENDIAN,
268 (wchar_t *) to, len);
269
270 /* if success terminate and exit */
271 if (i >= 0)
272 goto success;
273 /*
274 * if fails fall back to UCS encoding as this
275 * function should not return negative values
276 * currently can fail only if source contains
277 * invalid encoded characters
278 */
279 }
280
281 for (i = 0; len && *from; i++, from += charlen, len -= charlen) {
282 charlen = codepage->char2uni(from, len, &wchar_to);
283 if (charlen < 1) {
284 cifs_dbg(VFS, "strtoUTF16: char2uni of 0x%x returned %d\n",
285 *from, charlen);
286 /* A question mark */
287 wchar_to = 0x003f;
288 charlen = 1;
289 }
290 put_unaligned_le16(wchar_to, &to[i]);
291 }
292
293 success:
294 put_unaligned_le16(0, &to[i]);
295 return i;
296 }
297
298 /*
299 * cifs_utf16_bytes - how long will a string be after conversion?
300 * @utf16 - pointer to input string
301 * @maxbytes - don't go past this many bytes of input string
302 * @codepage - destination codepage
303 *
304 * Walk a utf16le string and return the number of bytes that the string will
305 * be after being converted to the given charset, not including any null
306 * termination required. Don't walk past maxbytes in the source buffer.
307 */
308 int
cifs_utf16_bytes(const __le16 * from,int maxbytes,const struct nls_table * codepage)309 cifs_utf16_bytes(const __le16 *from, int maxbytes,
310 const struct nls_table *codepage)
311 {
312 int i;
313 int charlen, outlen = 0;
314 int maxwords = maxbytes / 2;
315 char tmp[NLS_MAX_CHARSET_SIZE];
316 __u16 ftmp[3];
317
318 for (i = 0; i < maxwords; i++) {
319 ftmp[0] = get_unaligned_le16(&from[i]);
320 if (ftmp[0] == 0)
321 break;
322 if (i + 1 < maxwords)
323 ftmp[1] = get_unaligned_le16(&from[i + 1]);
324 else
325 ftmp[1] = 0;
326 if (i + 2 < maxwords)
327 ftmp[2] = get_unaligned_le16(&from[i + 2]);
328 else
329 ftmp[2] = 0;
330
331 charlen = cifs_mapchar(tmp, ftmp, codepage, NO_MAP_UNI_RSVD);
332 outlen += charlen;
333 }
334
335 return outlen;
336 }
337
338 /*
339 * cifs_strndup_from_utf16 - copy a string from wire format to the local
340 * codepage
341 * @src - source string
342 * @maxlen - don't walk past this many bytes in the source string
343 * @is_unicode - is this a unicode string?
344 * @codepage - destination codepage
345 *
346 * Take a string given by the server, convert it to the local codepage and
347 * put it in a new buffer. Returns a pointer to the new string or NULL on
348 * error.
349 */
350 char *
cifs_strndup_from_utf16(const char * src,const int maxlen,const bool is_unicode,const struct nls_table * codepage)351 cifs_strndup_from_utf16(const char *src, const int maxlen,
352 const bool is_unicode, const struct nls_table *codepage)
353 {
354 int len;
355 char *dst;
356
357 if (is_unicode) {
358 len = cifs_utf16_bytes((__le16 *) src, maxlen, codepage);
359 len += nls_nullsize(codepage);
360 dst = kmalloc(len, GFP_KERNEL);
361 if (!dst)
362 return NULL;
363 cifs_from_utf16(dst, (__le16 *) src, len, maxlen, codepage,
364 NO_MAP_UNI_RSVD);
365 } else {
366 len = strnlen(src, maxlen);
367 len++;
368 dst = kmalloc(len, GFP_KERNEL);
369 if (!dst)
370 return NULL;
371 strlcpy(dst, src, len);
372 }
373
374 return dst;
375 }
376
convert_to_sfu_char(char src_char)377 static __le16 convert_to_sfu_char(char src_char)
378 {
379 __le16 dest_char;
380
381 switch (src_char) {
382 case ':':
383 dest_char = cpu_to_le16(UNI_COLON);
384 break;
385 case '*':
386 dest_char = cpu_to_le16(UNI_ASTERISK);
387 break;
388 case '?':
389 dest_char = cpu_to_le16(UNI_QUESTION);
390 break;
391 case '<':
392 dest_char = cpu_to_le16(UNI_LESSTHAN);
393 break;
394 case '>':
395 dest_char = cpu_to_le16(UNI_GRTRTHAN);
396 break;
397 case '|':
398 dest_char = cpu_to_le16(UNI_PIPE);
399 break;
400 default:
401 dest_char = 0;
402 }
403
404 return dest_char;
405 }
406
convert_to_sfm_char(char src_char)407 static __le16 convert_to_sfm_char(char src_char)
408 {
409 __le16 dest_char;
410
411 switch (src_char) {
412 case ':':
413 dest_char = cpu_to_le16(SFM_COLON);
414 break;
415 case '*':
416 dest_char = cpu_to_le16(SFM_ASTERISK);
417 break;
418 case '?':
419 dest_char = cpu_to_le16(SFM_QUESTION);
420 break;
421 case '<':
422 dest_char = cpu_to_le16(SFM_LESSTHAN);
423 break;
424 case '>':
425 dest_char = cpu_to_le16(SFM_GRTRTHAN);
426 break;
427 case '|':
428 dest_char = cpu_to_le16(SFM_PIPE);
429 break;
430 default:
431 dest_char = 0;
432 }
433
434 return dest_char;
435 }
436
437 /*
438 * Convert 16 bit Unicode pathname to wire format from string in current code
439 * page. Conversion may involve remapping up the six characters that are
440 * only legal in POSIX-like OS (if they are present in the string). Path
441 * names are little endian 16 bit Unicode on the wire
442 */
443 int
cifsConvertToUTF16(__le16 * target,const char * source,int srclen,const struct nls_table * cp,int map_chars)444 cifsConvertToUTF16(__le16 *target, const char *source, int srclen,
445 const struct nls_table *cp, int map_chars)
446 {
447 int i, charlen;
448 int j = 0;
449 char src_char;
450 __le16 dst_char;
451 wchar_t tmp;
452 wchar_t *wchar_to; /* UTF-16 */
453 int ret;
454 unicode_t u;
455
456 if (map_chars == NO_MAP_UNI_RSVD)
457 return cifs_strtoUTF16(target, source, PATH_MAX, cp);
458
459 wchar_to = kzalloc(6, GFP_KERNEL);
460
461 for (i = 0; i < srclen; j++) {
462 src_char = source[i];
463 charlen = 1;
464
465 /* check if end of string */
466 if (src_char == 0)
467 goto ctoUTF16_out;
468
469 /* see if we must remap this char */
470 if (map_chars == SFU_MAP_UNI_RSVD)
471 dst_char = convert_to_sfu_char(src_char);
472 else if (map_chars == SFM_MAP_UNI_RSVD)
473 dst_char = convert_to_sfm_char(src_char);
474 else
475 dst_char = 0;
476 /*
477 * FIXME: We can not handle remapping backslash (UNI_SLASH)
478 * until all the calls to build_path_from_dentry are modified,
479 * as they use backslash as separator.
480 */
481 if (dst_char == 0) {
482 charlen = cp->char2uni(source + i, srclen - i, &tmp);
483 dst_char = cpu_to_le16(tmp);
484
485 /*
486 * if no match, use question mark, which at least in
487 * some cases serves as wild card
488 */
489 if (charlen > 0)
490 goto ctoUTF16;
491
492 /* convert SURROGATE_PAIR */
493 if (strcmp(cp->charset, "utf8") || !wchar_to)
494 goto unknown;
495 if (*(source + i) & 0x80) {
496 charlen = utf8_to_utf32(source + i, 6, &u);
497 if (charlen < 0)
498 goto unknown;
499 } else
500 goto unknown;
501 ret = utf8s_to_utf16s(source + i, charlen,
502 UTF16_LITTLE_ENDIAN,
503 wchar_to, 6);
504 if (ret < 0)
505 goto unknown;
506
507 i += charlen;
508 dst_char = cpu_to_le16(*wchar_to);
509 if (charlen <= 3)
510 /* 1-3bytes UTF-8 to 2bytes UTF-16 */
511 put_unaligned(dst_char, &target[j]);
512 else if (charlen == 4) {
513 /* 4bytes UTF-8(surrogate pair) to 4bytes UTF-16
514 * 7-8bytes UTF-8(IVS) divided to 2 UTF-16
515 * (charlen=3+4 or 4+4) */
516 put_unaligned(dst_char, &target[j]);
517 dst_char = cpu_to_le16(*(wchar_to + 1));
518 j++;
519 put_unaligned(dst_char, &target[j]);
520 } else if (charlen >= 5) {
521 /* 5-6bytes UTF-8 to 6bytes UTF-16 */
522 put_unaligned(dst_char, &target[j]);
523 dst_char = cpu_to_le16(*(wchar_to + 1));
524 j++;
525 put_unaligned(dst_char, &target[j]);
526 dst_char = cpu_to_le16(*(wchar_to + 2));
527 j++;
528 put_unaligned(dst_char, &target[j]);
529 }
530 continue;
531
532 unknown:
533 dst_char = cpu_to_le16(0x003f);
534 charlen = 1;
535 }
536
537 ctoUTF16:
538 /*
539 * character may take more than one byte in the source string,
540 * but will take exactly two bytes in the target string
541 */
542 i += charlen;
543 put_unaligned(dst_char, &target[j]);
544 }
545
546 ctoUTF16_out:
547 put_unaligned(0, &target[j]); /* Null terminate target unicode string */
548 kfree(wchar_to);
549 return j;
550 }
551
552 #ifdef CONFIG_CIFS_SMB2
553 /*
554 * cifs_local_to_utf16_bytes - how long will a string be after conversion?
555 * @from - pointer to input string
556 * @maxbytes - don't go past this many bytes of input string
557 * @codepage - source codepage
558 *
559 * Walk a string and return the number of bytes that the string will
560 * be after being converted to the given charset, not including any null
561 * termination required. Don't walk past maxbytes in the source buffer.
562 */
563
564 static int
cifs_local_to_utf16_bytes(const char * from,int len,const struct nls_table * codepage)565 cifs_local_to_utf16_bytes(const char *from, int len,
566 const struct nls_table *codepage)
567 {
568 int charlen;
569 int i;
570 wchar_t wchar_to;
571
572 for (i = 0; len && *from; i++, from += charlen, len -= charlen) {
573 charlen = codepage->char2uni(from, len, &wchar_to);
574 /* Failed conversion defaults to a question mark */
575 if (charlen < 1)
576 charlen = 1;
577 }
578 return 2 * i; /* UTF16 characters are two bytes */
579 }
580
581 /*
582 * cifs_strndup_to_utf16 - copy a string to wire format from the local codepage
583 * @src - source string
584 * @maxlen - don't walk past this many bytes in the source string
585 * @utf16_len - the length of the allocated string in bytes (including null)
586 * @cp - source codepage
587 * @remap - map special chars
588 *
589 * Take a string convert it from the local codepage to UTF16 and
590 * put it in a new buffer. Returns a pointer to the new string or NULL on
591 * error.
592 */
593 __le16 *
cifs_strndup_to_utf16(const char * src,const int maxlen,int * utf16_len,const struct nls_table * cp,int remap)594 cifs_strndup_to_utf16(const char *src, const int maxlen, int *utf16_len,
595 const struct nls_table *cp, int remap)
596 {
597 int len;
598 __le16 *dst;
599
600 len = cifs_local_to_utf16_bytes(src, maxlen, cp);
601 len += 2; /* NULL */
602 dst = kmalloc(len, GFP_KERNEL);
603 if (!dst) {
604 *utf16_len = 0;
605 return NULL;
606 }
607 cifsConvertToUTF16(dst, src, strlen(src), cp, remap);
608 *utf16_len = len;
609 return dst;
610 }
611 #endif /* CONFIG_CIFS_SMB2 */
612