1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3 *
4 * Copyright (c) International Business Machines Corp., 2000,2009
5 * Modified by Steve French (sfrench@us.ibm.com)
6 */
7 #include <linux/fs.h>
8 #include <linux/slab.h>
9 #include "cifs_fs_sb.h"
10 #include "cifs_unicode.h"
11 #include "cifsglob.h"
12 #include "cifs_debug.h"
13
14 /* Convert character using the SFU - "Services for Unix" remapping range */
15 static bool
convert_sfu_char(const __u16 src_char,char * target)16 convert_sfu_char(const __u16 src_char, char *target)
17 {
18 /*
19 * BB: Cannot handle remapping UNI_SLASH until all the calls to
20 * build_path_from_dentry are modified, as they use slash as
21 * separator.
22 */
23 switch (src_char) {
24 case UNI_COLON:
25 *target = ':';
26 break;
27 case UNI_ASTERISK:
28 *target = '*';
29 break;
30 case UNI_QUESTION:
31 *target = '?';
32 break;
33 case UNI_PIPE:
34 *target = '|';
35 break;
36 case UNI_GRTRTHAN:
37 *target = '>';
38 break;
39 case UNI_LESSTHAN:
40 *target = '<';
41 break;
42 default:
43 return false;
44 }
45 return true;
46 }
47
48 /* Convert character using the SFM - "Services for Mac" remapping range */
49 static bool
convert_sfm_char(const __u16 src_char,char * target)50 convert_sfm_char(const __u16 src_char, char *target)
51 {
52 if (src_char >= 0xF001 && src_char <= 0xF01F) {
53 *target = src_char - 0xF000;
54 return true;
55 }
56 switch (src_char) {
57 case SFM_COLON:
58 *target = ':';
59 break;
60 case SFM_DOUBLEQUOTE:
61 *target = '"';
62 break;
63 case SFM_ASTERISK:
64 *target = '*';
65 break;
66 case SFM_QUESTION:
67 *target = '?';
68 break;
69 case SFM_PIPE:
70 *target = '|';
71 break;
72 case SFM_GRTRTHAN:
73 *target = '>';
74 break;
75 case SFM_LESSTHAN:
76 *target = '<';
77 break;
78 case SFM_SPACE:
79 *target = ' ';
80 break;
81 case SFM_PERIOD:
82 *target = '.';
83 break;
84 default:
85 return false;
86 }
87 return true;
88 }
89
90
91 /*
92 * cifs_mapchar - convert a host-endian char to proper char in codepage
93 * @target - where converted character should be copied
94 * @src_char - 2 byte host-endian source character
95 * @cp - codepage to which character should be converted
96 * @map_type - How should the 7 NTFS/SMB reserved characters be mapped to UCS2?
97 *
98 * This function handles the conversion of a single character. It is the
99 * responsibility of the caller to ensure that the target buffer is large
100 * enough to hold the result of the conversion (at least NLS_MAX_CHARSET_SIZE).
101 */
102 static int
cifs_mapchar(char * target,const __u16 * from,const struct nls_table * cp,int maptype)103 cifs_mapchar(char *target, const __u16 *from, const struct nls_table *cp,
104 int maptype)
105 {
106 int len = 1;
107 __u16 src_char;
108
109 src_char = *from;
110
111 if ((maptype == SFM_MAP_UNI_RSVD) && convert_sfm_char(src_char, target))
112 return len;
113 else if ((maptype == SFU_MAP_UNI_RSVD) &&
114 convert_sfu_char(src_char, target))
115 return len;
116
117 /* if character not one of seven in special remap set */
118 len = cp->uni2char(src_char, target, NLS_MAX_CHARSET_SIZE);
119 if (len <= 0)
120 goto surrogate_pair;
121
122 return len;
123
124 surrogate_pair:
125 /* convert SURROGATE_PAIR and IVS */
126 if (strcmp(cp->charset, "utf8"))
127 goto unknown;
128 len = utf16s_to_utf8s(from, 3, UTF16_LITTLE_ENDIAN, target, 6);
129 if (len <= 0)
130 goto unknown;
131 return len;
132
133 unknown:
134 *target = '?';
135 len = 1;
136 return len;
137 }
138
139 /*
140 * cifs_from_utf16 - convert utf16le string to local charset
141 * @to - destination buffer
142 * @from - source buffer
143 * @tolen - destination buffer size (in bytes)
144 * @fromlen - source buffer size (in bytes)
145 * @codepage - codepage to which characters should be converted
146 * @mapchar - should characters be remapped according to the mapchars option?
147 *
148 * Convert a little-endian utf16le string (as sent by the server) to a string
149 * in the provided codepage. The tolen and fromlen parameters are to ensure
150 * that the code doesn't walk off of the end of the buffer (which is always
151 * a danger if the alignment of the source buffer is off). The destination
152 * string is always properly null terminated and fits in the destination
153 * buffer. Returns the length of the destination string in bytes (including
154 * null terminator).
155 *
156 * Note that some windows versions actually send multiword UTF-16 characters
157 * instead of straight UTF16-2. The linux nls routines however aren't able to
158 * deal with those characters properly. In the event that we get some of
159 * those characters, they won't be translated properly.
160 */
161 int
cifs_from_utf16(char * to,const __le16 * from,int tolen,int fromlen,const struct nls_table * codepage,int map_type)162 cifs_from_utf16(char *to, const __le16 *from, int tolen, int fromlen,
163 const struct nls_table *codepage, int map_type)
164 {
165 int i, charlen, safelen;
166 int outlen = 0;
167 int nullsize = nls_nullsize(codepage);
168 int fromwords = fromlen / 2;
169 char tmp[NLS_MAX_CHARSET_SIZE];
170 __u16 ftmp[3]; /* ftmp[3] = 3array x 2bytes = 6bytes UTF-16 */
171
172 /*
173 * because the chars can be of varying widths, we need to take care
174 * not to overflow the destination buffer when we get close to the
175 * end of it. Until we get to this offset, we don't need to check
176 * for overflow however.
177 */
178 safelen = tolen - (NLS_MAX_CHARSET_SIZE + nullsize);
179
180 for (i = 0; i < fromwords; i++) {
181 ftmp[0] = get_unaligned_le16(&from[i]);
182 if (ftmp[0] == 0)
183 break;
184 if (i + 1 < fromwords)
185 ftmp[1] = get_unaligned_le16(&from[i + 1]);
186 else
187 ftmp[1] = 0;
188 if (i + 2 < fromwords)
189 ftmp[2] = get_unaligned_le16(&from[i + 2]);
190 else
191 ftmp[2] = 0;
192
193 /*
194 * check to see if converting this character might make the
195 * conversion bleed into the null terminator
196 */
197 if (outlen >= safelen) {
198 charlen = cifs_mapchar(tmp, ftmp, codepage, map_type);
199 if ((outlen + charlen) > (tolen - nullsize))
200 break;
201 }
202
203 /* put converted char into 'to' buffer */
204 charlen = cifs_mapchar(&to[outlen], ftmp, codepage, map_type);
205 outlen += charlen;
206
207 /* charlen (=bytes of UTF-8 for 1 character)
208 * 4bytes UTF-8(surrogate pair) is charlen=4
209 * (4bytes UTF-16 code)
210 * 7-8bytes UTF-8(IVS) is charlen=3+4 or 4+4
211 * (2 UTF-8 pairs divided to 2 UTF-16 pairs) */
212 if (charlen == 4)
213 i++;
214 else if (charlen >= 5)
215 /* 5-6bytes UTF-8 */
216 i += 2;
217 }
218
219 /* properly null-terminate string */
220 for (i = 0; i < nullsize; i++)
221 to[outlen++] = 0;
222
223 return outlen;
224 }
225
226 /*
227 * NAME: cifs_strtoUTF16()
228 *
229 * FUNCTION: Convert character string to unicode string
230 *
231 */
232 int
cifs_strtoUTF16(__le16 * to,const char * from,int len,const struct nls_table * codepage)233 cifs_strtoUTF16(__le16 *to, const char *from, int len,
234 const struct nls_table *codepage)
235 {
236 int charlen;
237 int i;
238 wchar_t wchar_to; /* needed to quiet sparse */
239
240 /* special case for utf8 to handle no plane0 chars */
241 if (!strcmp(codepage->charset, "utf8")) {
242 /*
243 * convert utf8 -> utf16, we assume we have enough space
244 * as caller should have assumed conversion does not overflow
245 * in destination len is length in wchar_t units (16bits)
246 */
247 i = utf8s_to_utf16s(from, len, UTF16_LITTLE_ENDIAN,
248 (wchar_t *) to, len);
249
250 /* if success terminate and exit */
251 if (i >= 0)
252 goto success;
253 /*
254 * if fails fall back to UCS encoding as this
255 * function should not return negative values
256 * currently can fail only if source contains
257 * invalid encoded characters
258 */
259 }
260
261 for (i = 0; len && *from; i++, from += charlen, len -= charlen) {
262 charlen = codepage->char2uni(from, len, &wchar_to);
263 if (charlen < 1) {
264 cifs_dbg(VFS, "strtoUTF16: char2uni of 0x%x returned %d\n",
265 *from, charlen);
266 /* A question mark */
267 wchar_to = 0x003f;
268 charlen = 1;
269 }
270 put_unaligned_le16(wchar_to, &to[i]);
271 }
272
273 success:
274 put_unaligned_le16(0, &to[i]);
275 return i;
276 }
277
278 /*
279 * cifs_utf16_bytes - how long will a string be after conversion?
280 * @utf16 - pointer to input string
281 * @maxbytes - don't go past this many bytes of input string
282 * @codepage - destination codepage
283 *
284 * Walk a utf16le string and return the number of bytes that the string will
285 * be after being converted to the given charset, not including any null
286 * termination required. Don't walk past maxbytes in the source buffer.
287 */
288 int
cifs_utf16_bytes(const __le16 * from,int maxbytes,const struct nls_table * codepage)289 cifs_utf16_bytes(const __le16 *from, int maxbytes,
290 const struct nls_table *codepage)
291 {
292 int i;
293 int charlen, outlen = 0;
294 int maxwords = maxbytes / 2;
295 char tmp[NLS_MAX_CHARSET_SIZE];
296 __u16 ftmp[3];
297
298 for (i = 0; i < maxwords; i++) {
299 ftmp[0] = get_unaligned_le16(&from[i]);
300 if (ftmp[0] == 0)
301 break;
302 if (i + 1 < maxwords)
303 ftmp[1] = get_unaligned_le16(&from[i + 1]);
304 else
305 ftmp[1] = 0;
306 if (i + 2 < maxwords)
307 ftmp[2] = get_unaligned_le16(&from[i + 2]);
308 else
309 ftmp[2] = 0;
310
311 charlen = cifs_mapchar(tmp, ftmp, codepage, NO_MAP_UNI_RSVD);
312 outlen += charlen;
313 }
314
315 return outlen;
316 }
317
318 /*
319 * cifs_strndup_from_utf16 - copy a string from wire format to the local
320 * codepage
321 * @src - source string
322 * @maxlen - don't walk past this many bytes in the source string
323 * @is_unicode - is this a unicode string?
324 * @codepage - destination codepage
325 *
326 * Take a string given by the server, convert it to the local codepage and
327 * put it in a new buffer. Returns a pointer to the new string or NULL on
328 * error.
329 */
330 char *
cifs_strndup_from_utf16(const char * src,const int maxlen,const bool is_unicode,const struct nls_table * codepage)331 cifs_strndup_from_utf16(const char *src, const int maxlen,
332 const bool is_unicode, const struct nls_table *codepage)
333 {
334 int len;
335 char *dst;
336
337 if (is_unicode) {
338 len = cifs_utf16_bytes((__le16 *) src, maxlen, codepage);
339 len += nls_nullsize(codepage);
340 dst = kmalloc(len, GFP_KERNEL);
341 if (!dst)
342 return NULL;
343 cifs_from_utf16(dst, (__le16 *) src, len, maxlen, codepage,
344 NO_MAP_UNI_RSVD);
345 } else {
346 dst = kstrndup(src, maxlen, GFP_KERNEL);
347 }
348
349 return dst;
350 }
351
convert_to_sfu_char(char src_char)352 static __le16 convert_to_sfu_char(char src_char)
353 {
354 __le16 dest_char;
355
356 switch (src_char) {
357 case ':':
358 dest_char = cpu_to_le16(UNI_COLON);
359 break;
360 case '*':
361 dest_char = cpu_to_le16(UNI_ASTERISK);
362 break;
363 case '?':
364 dest_char = cpu_to_le16(UNI_QUESTION);
365 break;
366 case '<':
367 dest_char = cpu_to_le16(UNI_LESSTHAN);
368 break;
369 case '>':
370 dest_char = cpu_to_le16(UNI_GRTRTHAN);
371 break;
372 case '|':
373 dest_char = cpu_to_le16(UNI_PIPE);
374 break;
375 default:
376 dest_char = 0;
377 }
378
379 return dest_char;
380 }
381
convert_to_sfm_char(char src_char,bool end_of_string)382 static __le16 convert_to_sfm_char(char src_char, bool end_of_string)
383 {
384 __le16 dest_char;
385
386 if (src_char >= 0x01 && src_char <= 0x1F) {
387 dest_char = cpu_to_le16(src_char + 0xF000);
388 return dest_char;
389 }
390 switch (src_char) {
391 case ':':
392 dest_char = cpu_to_le16(SFM_COLON);
393 break;
394 case '"':
395 dest_char = cpu_to_le16(SFM_DOUBLEQUOTE);
396 break;
397 case '*':
398 dest_char = cpu_to_le16(SFM_ASTERISK);
399 break;
400 case '?':
401 dest_char = cpu_to_le16(SFM_QUESTION);
402 break;
403 case '<':
404 dest_char = cpu_to_le16(SFM_LESSTHAN);
405 break;
406 case '>':
407 dest_char = cpu_to_le16(SFM_GRTRTHAN);
408 break;
409 case '|':
410 dest_char = cpu_to_le16(SFM_PIPE);
411 break;
412 case '.':
413 if (end_of_string)
414 dest_char = cpu_to_le16(SFM_PERIOD);
415 else
416 dest_char = 0;
417 break;
418 case ' ':
419 if (end_of_string)
420 dest_char = cpu_to_le16(SFM_SPACE);
421 else
422 dest_char = 0;
423 break;
424 default:
425 dest_char = 0;
426 }
427
428 return dest_char;
429 }
430
431 /*
432 * Convert 16 bit Unicode pathname to wire format from string in current code
433 * page. Conversion may involve remapping up the six characters that are
434 * only legal in POSIX-like OS (if they are present in the string). Path
435 * names are little endian 16 bit Unicode on the wire
436 */
437 int
cifsConvertToUTF16(__le16 * target,const char * source,int srclen,const struct nls_table * cp,int map_chars)438 cifsConvertToUTF16(__le16 *target, const char *source, int srclen,
439 const struct nls_table *cp, int map_chars)
440 {
441 int i, charlen;
442 int j = 0;
443 char src_char;
444 __le16 dst_char;
445 wchar_t tmp;
446 wchar_t *wchar_to; /* UTF-16 */
447 int ret;
448 unicode_t u;
449
450 if (map_chars == NO_MAP_UNI_RSVD)
451 return cifs_strtoUTF16(target, source, PATH_MAX, cp);
452
453 wchar_to = kzalloc(6, GFP_KERNEL);
454
455 for (i = 0; i < srclen; j++) {
456 src_char = source[i];
457 charlen = 1;
458
459 /* check if end of string */
460 if (src_char == 0)
461 goto ctoUTF16_out;
462
463 /* see if we must remap this char */
464 if (map_chars == SFU_MAP_UNI_RSVD)
465 dst_char = convert_to_sfu_char(src_char);
466 else if (map_chars == SFM_MAP_UNI_RSVD) {
467 bool end_of_string;
468
469 /**
470 * Remap spaces and periods found at the end of every
471 * component of the path. The special cases of '.' and
472 * '..' are need to be handled because of symlinks.
473 * They are treated as non-end-of-string to avoid
474 * remapping and breaking symlinks pointing to . or ..
475 **/
476 if ((i == 0 || source[i-1] == '\\') &&
477 source[i] == '.' &&
478 (i == srclen-1 || source[i+1] == '\\'))
479 end_of_string = false; /* "." case */
480 else if (i >= 1 &&
481 (i == 1 || source[i-2] == '\\') &&
482 source[i-1] == '.' &&
483 source[i] == '.' &&
484 (i == srclen-1 || source[i+1] == '\\'))
485 end_of_string = false; /* ".." case */
486 else if ((i == srclen - 1) || (source[i+1] == '\\'))
487 end_of_string = true;
488 else
489 end_of_string = false;
490
491 dst_char = convert_to_sfm_char(src_char, end_of_string);
492 } else
493 dst_char = 0;
494 /*
495 * FIXME: We can not handle remapping backslash (UNI_SLASH)
496 * until all the calls to build_path_from_dentry are modified,
497 * as they use backslash as separator.
498 */
499 if (dst_char == 0) {
500 charlen = cp->char2uni(source + i, srclen - i, &tmp);
501 dst_char = cpu_to_le16(tmp);
502
503 /*
504 * if no match, use question mark, which at least in
505 * some cases serves as wild card
506 */
507 if (charlen > 0)
508 goto ctoUTF16;
509
510 /* convert SURROGATE_PAIR */
511 if (strcmp(cp->charset, "utf8") || !wchar_to)
512 goto unknown;
513 if (*(source + i) & 0x80) {
514 charlen = utf8_to_utf32(source + i, 6, &u);
515 if (charlen < 0)
516 goto unknown;
517 } else
518 goto unknown;
519 ret = utf8s_to_utf16s(source + i, charlen,
520 UTF16_LITTLE_ENDIAN,
521 wchar_to, 6);
522 if (ret < 0)
523 goto unknown;
524
525 i += charlen;
526 dst_char = cpu_to_le16(*wchar_to);
527 if (charlen <= 3)
528 /* 1-3bytes UTF-8 to 2bytes UTF-16 */
529 put_unaligned(dst_char, &target[j]);
530 else if (charlen == 4) {
531 /* 4bytes UTF-8(surrogate pair) to 4bytes UTF-16
532 * 7-8bytes UTF-8(IVS) divided to 2 UTF-16
533 * (charlen=3+4 or 4+4) */
534 put_unaligned(dst_char, &target[j]);
535 dst_char = cpu_to_le16(*(wchar_to + 1));
536 j++;
537 put_unaligned(dst_char, &target[j]);
538 } else if (charlen >= 5) {
539 /* 5-6bytes UTF-8 to 6bytes UTF-16 */
540 put_unaligned(dst_char, &target[j]);
541 dst_char = cpu_to_le16(*(wchar_to + 1));
542 j++;
543 put_unaligned(dst_char, &target[j]);
544 dst_char = cpu_to_le16(*(wchar_to + 2));
545 j++;
546 put_unaligned(dst_char, &target[j]);
547 }
548 continue;
549
550 unknown:
551 dst_char = cpu_to_le16(0x003f);
552 charlen = 1;
553 }
554
555 ctoUTF16:
556 /*
557 * character may take more than one byte in the source string,
558 * but will take exactly two bytes in the target string
559 */
560 i += charlen;
561 put_unaligned(dst_char, &target[j]);
562 }
563
564 ctoUTF16_out:
565 put_unaligned(0, &target[j]); /* Null terminate target unicode string */
566 kfree(wchar_to);
567 return j;
568 }
569
570 /*
571 * cifs_local_to_utf16_bytes - how long will a string be after conversion?
572 * @from - pointer to input string
573 * @maxbytes - don't go past this many bytes of input string
574 * @codepage - source codepage
575 *
576 * Walk a string and return the number of bytes that the string will
577 * be after being converted to the given charset, not including any null
578 * termination required. Don't walk past maxbytes in the source buffer.
579 */
580
581 static int
cifs_local_to_utf16_bytes(const char * from,int len,const struct nls_table * codepage)582 cifs_local_to_utf16_bytes(const char *from, int len,
583 const struct nls_table *codepage)
584 {
585 int charlen;
586 int i;
587 wchar_t wchar_to;
588
589 for (i = 0; len && *from; i++, from += charlen, len -= charlen) {
590 charlen = codepage->char2uni(from, len, &wchar_to);
591 /* Failed conversion defaults to a question mark */
592 if (charlen < 1)
593 charlen = 1;
594 }
595 return 2 * i; /* UTF16 characters are two bytes */
596 }
597
598 /*
599 * cifs_strndup_to_utf16 - copy a string to wire format from the local codepage
600 * @src - source string
601 * @maxlen - don't walk past this many bytes in the source string
602 * @utf16_len - the length of the allocated string in bytes (including null)
603 * @cp - source codepage
604 * @remap - map special chars
605 *
606 * Take a string convert it from the local codepage to UTF16 and
607 * put it in a new buffer. Returns a pointer to the new string or NULL on
608 * error.
609 */
610 __le16 *
cifs_strndup_to_utf16(const char * src,const int maxlen,int * utf16_len,const struct nls_table * cp,int remap)611 cifs_strndup_to_utf16(const char *src, const int maxlen, int *utf16_len,
612 const struct nls_table *cp, int remap)
613 {
614 int len;
615 __le16 *dst;
616
617 if (!src)
618 return NULL;
619
620 len = cifs_local_to_utf16_bytes(src, maxlen, cp);
621 len += 2; /* NULL */
622 dst = kmalloc(len, GFP_KERNEL);
623 if (!dst) {
624 *utf16_len = 0;
625 return NULL;
626 }
627 cifsConvertToUTF16(dst, src, strlen(src), cp, remap);
628 *utf16_len = len;
629 return dst;
630 }
631