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 "cifspdu.h"
12 #include "cifsglob.h"
13 #include "cifs_debug.h"
14
cifs_remap(struct cifs_sb_info * cifs_sb)15 int cifs_remap(struct cifs_sb_info *cifs_sb)
16 {
17 int map_type;
18
19 if (cifs_sb->mnt_cifs_flags & CIFS_MOUNT_MAP_SFM_CHR)
20 map_type = SFM_MAP_UNI_RSVD;
21 else if (cifs_sb->mnt_cifs_flags & CIFS_MOUNT_MAP_SPECIAL_CHR)
22 map_type = SFU_MAP_UNI_RSVD;
23 else
24 map_type = NO_MAP_UNI_RSVD;
25
26 return map_type;
27 }
28
29 /* Convert character using the SFU - "Services for Unix" remapping range */
30 static bool
convert_sfu_char(const __u16 src_char,char * target)31 convert_sfu_char(const __u16 src_char, char *target)
32 {
33 /*
34 * BB: Cannot handle remapping UNI_SLASH until all the calls to
35 * build_path_from_dentry are modified, as they use slash as
36 * separator.
37 */
38 switch (src_char) {
39 case UNI_COLON:
40 *target = ':';
41 break;
42 case UNI_ASTERISK:
43 *target = '*';
44 break;
45 case UNI_QUESTION:
46 *target = '?';
47 break;
48 case UNI_PIPE:
49 *target = '|';
50 break;
51 case UNI_GRTRTHAN:
52 *target = '>';
53 break;
54 case UNI_LESSTHAN:
55 *target = '<';
56 break;
57 default:
58 return false;
59 }
60 return true;
61 }
62
63 /* Convert character using the SFM - "Services for Mac" remapping range */
64 static bool
convert_sfm_char(const __u16 src_char,char * target)65 convert_sfm_char(const __u16 src_char, char *target)
66 {
67 if (src_char >= 0xF001 && src_char <= 0xF01F) {
68 *target = src_char - 0xF000;
69 return true;
70 }
71 switch (src_char) {
72 case SFM_COLON:
73 *target = ':';
74 break;
75 case SFM_DOUBLEQUOTE:
76 *target = '"';
77 break;
78 case SFM_ASTERISK:
79 *target = '*';
80 break;
81 case SFM_QUESTION:
82 *target = '?';
83 break;
84 case SFM_PIPE:
85 *target = '|';
86 break;
87 case SFM_GRTRTHAN:
88 *target = '>';
89 break;
90 case SFM_LESSTHAN:
91 *target = '<';
92 break;
93 case SFM_SPACE:
94 *target = ' ';
95 break;
96 case SFM_PERIOD:
97 *target = '.';
98 break;
99 default:
100 return false;
101 }
102 return true;
103 }
104
105
106 /*
107 * cifs_mapchar - convert a host-endian char to proper char in codepage
108 * @target - where converted character should be copied
109 * @src_char - 2 byte host-endian source character
110 * @cp - codepage to which character should be converted
111 * @map_type - How should the 7 NTFS/SMB reserved characters be mapped to UCS2?
112 *
113 * This function handles the conversion of a single character. It is the
114 * responsibility of the caller to ensure that the target buffer is large
115 * enough to hold the result of the conversion (at least NLS_MAX_CHARSET_SIZE).
116 */
117 static int
cifs_mapchar(char * target,const __u16 * from,const struct nls_table * cp,int maptype)118 cifs_mapchar(char *target, const __u16 *from, const struct nls_table *cp,
119 int maptype)
120 {
121 int len = 1;
122 __u16 src_char;
123
124 src_char = *from;
125
126 if ((maptype == SFM_MAP_UNI_RSVD) && convert_sfm_char(src_char, target))
127 return len;
128 else if ((maptype == SFU_MAP_UNI_RSVD) &&
129 convert_sfu_char(src_char, target))
130 return len;
131
132 /* if character not one of seven in special remap set */
133 len = cp->uni2char(src_char, target, NLS_MAX_CHARSET_SIZE);
134 if (len <= 0)
135 goto surrogate_pair;
136
137 return len;
138
139 surrogate_pair:
140 /* convert SURROGATE_PAIR and IVS */
141 if (strcmp(cp->charset, "utf8"))
142 goto unknown;
143 len = utf16s_to_utf8s(from, 3, UTF16_LITTLE_ENDIAN, target, 6);
144 if (len <= 0)
145 goto unknown;
146 return len;
147
148 unknown:
149 *target = '?';
150 len = 1;
151 return len;
152 }
153
154 /*
155 * cifs_from_utf16 - convert utf16le string to local charset
156 * @to - destination buffer
157 * @from - source buffer
158 * @tolen - destination buffer size (in bytes)
159 * @fromlen - source buffer size (in bytes)
160 * @codepage - codepage to which characters should be converted
161 * @mapchar - should characters be remapped according to the mapchars option?
162 *
163 * Convert a little-endian utf16le string (as sent by the server) to a string
164 * in the provided codepage. The tolen and fromlen parameters are to ensure
165 * that the code doesn't walk off of the end of the buffer (which is always
166 * a danger if the alignment of the source buffer is off). The destination
167 * string is always properly null terminated and fits in the destination
168 * buffer. Returns the length of the destination string in bytes (including
169 * null terminator).
170 *
171 * Note that some windows versions actually send multiword UTF-16 characters
172 * instead of straight UTF16-2. The linux nls routines however aren't able to
173 * deal with those characters properly. In the event that we get some of
174 * those characters, they won't be translated properly.
175 */
176 int
cifs_from_utf16(char * to,const __le16 * from,int tolen,int fromlen,const struct nls_table * codepage,int map_type)177 cifs_from_utf16(char *to, const __le16 *from, int tolen, int fromlen,
178 const struct nls_table *codepage, int map_type)
179 {
180 int i, charlen, safelen;
181 int outlen = 0;
182 int nullsize = nls_nullsize(codepage);
183 int fromwords = fromlen / 2;
184 char tmp[NLS_MAX_CHARSET_SIZE];
185 __u16 ftmp[3]; /* ftmp[3] = 3array x 2bytes = 6bytes UTF-16 */
186
187 /*
188 * because the chars can be of varying widths, we need to take care
189 * not to overflow the destination buffer when we get close to the
190 * end of it. Until we get to this offset, we don't need to check
191 * for overflow however.
192 */
193 safelen = tolen - (NLS_MAX_CHARSET_SIZE + nullsize);
194
195 for (i = 0; i < fromwords; i++) {
196 ftmp[0] = get_unaligned_le16(&from[i]);
197 if (ftmp[0] == 0)
198 break;
199 if (i + 1 < fromwords)
200 ftmp[1] = get_unaligned_le16(&from[i + 1]);
201 else
202 ftmp[1] = 0;
203 if (i + 2 < fromwords)
204 ftmp[2] = get_unaligned_le16(&from[i + 2]);
205 else
206 ftmp[2] = 0;
207
208 /*
209 * check to see if converting this character might make the
210 * conversion bleed into the null terminator
211 */
212 if (outlen >= safelen) {
213 charlen = cifs_mapchar(tmp, ftmp, codepage, map_type);
214 if ((outlen + charlen) > (tolen - nullsize))
215 break;
216 }
217
218 /* put converted char into 'to' buffer */
219 charlen = cifs_mapchar(&to[outlen], ftmp, codepage, map_type);
220 outlen += charlen;
221
222 /* charlen (=bytes of UTF-8 for 1 character)
223 * 4bytes UTF-8(surrogate pair) is charlen=4
224 * (4bytes UTF-16 code)
225 * 7-8bytes UTF-8(IVS) is charlen=3+4 or 4+4
226 * (2 UTF-8 pairs divided to 2 UTF-16 pairs) */
227 if (charlen == 4)
228 i++;
229 else if (charlen >= 5)
230 /* 5-6bytes UTF-8 */
231 i += 2;
232 }
233
234 /* properly null-terminate string */
235 for (i = 0; i < nullsize; i++)
236 to[outlen++] = 0;
237
238 return outlen;
239 }
240
241 /*
242 * NAME: cifs_strtoUTF16()
243 *
244 * FUNCTION: Convert character string to unicode string
245 *
246 */
247 int
cifs_strtoUTF16(__le16 * to,const char * from,int len,const struct nls_table * codepage)248 cifs_strtoUTF16(__le16 *to, const char *from, int len,
249 const struct nls_table *codepage)
250 {
251 int charlen;
252 int i;
253 wchar_t wchar_to; /* needed to quiet sparse */
254
255 /* special case for utf8 to handle no plane0 chars */
256 if (!strcmp(codepage->charset, "utf8")) {
257 /*
258 * convert utf8 -> utf16, we assume we have enough space
259 * as caller should have assumed conversion does not overflow
260 * in destination len is length in wchar_t units (16bits)
261 */
262 i = utf8s_to_utf16s(from, len, UTF16_LITTLE_ENDIAN,
263 (wchar_t *) to, len);
264
265 /* if success terminate and exit */
266 if (i >= 0)
267 goto success;
268 /*
269 * if fails fall back to UCS encoding as this
270 * function should not return negative values
271 * currently can fail only if source contains
272 * invalid encoded characters
273 */
274 }
275
276 for (i = 0; len && *from; i++, from += charlen, len -= charlen) {
277 charlen = codepage->char2uni(from, len, &wchar_to);
278 if (charlen < 1) {
279 cifs_dbg(VFS, "strtoUTF16: char2uni of 0x%x returned %d\n",
280 *from, charlen);
281 /* A question mark */
282 wchar_to = 0x003f;
283 charlen = 1;
284 }
285 put_unaligned_le16(wchar_to, &to[i]);
286 }
287
288 success:
289 put_unaligned_le16(0, &to[i]);
290 return i;
291 }
292
293 /*
294 * cifs_utf16_bytes - how long will a string be after conversion?
295 * @utf16 - pointer to input string
296 * @maxbytes - don't go past this many bytes of input string
297 * @codepage - destination codepage
298 *
299 * Walk a utf16le string and return the number of bytes that the string will
300 * be after being converted to the given charset, not including any null
301 * termination required. Don't walk past maxbytes in the source buffer.
302 */
303 int
cifs_utf16_bytes(const __le16 * from,int maxbytes,const struct nls_table * codepage)304 cifs_utf16_bytes(const __le16 *from, int maxbytes,
305 const struct nls_table *codepage)
306 {
307 int i;
308 int charlen, outlen = 0;
309 int maxwords = maxbytes / 2;
310 char tmp[NLS_MAX_CHARSET_SIZE];
311 __u16 ftmp[3];
312
313 for (i = 0; i < maxwords; i++) {
314 ftmp[0] = get_unaligned_le16(&from[i]);
315 if (ftmp[0] == 0)
316 break;
317 if (i + 1 < maxwords)
318 ftmp[1] = get_unaligned_le16(&from[i + 1]);
319 else
320 ftmp[1] = 0;
321 if (i + 2 < maxwords)
322 ftmp[2] = get_unaligned_le16(&from[i + 2]);
323 else
324 ftmp[2] = 0;
325
326 charlen = cifs_mapchar(tmp, ftmp, codepage, NO_MAP_UNI_RSVD);
327 outlen += charlen;
328 }
329
330 return outlen;
331 }
332
333 /*
334 * cifs_strndup_from_utf16 - copy a string from wire format to the local
335 * codepage
336 * @src - source string
337 * @maxlen - don't walk past this many bytes in the source string
338 * @is_unicode - is this a unicode string?
339 * @codepage - destination codepage
340 *
341 * Take a string given by the server, convert it to the local codepage and
342 * put it in a new buffer. Returns a pointer to the new string or NULL on
343 * error.
344 */
345 char *
cifs_strndup_from_utf16(const char * src,const int maxlen,const bool is_unicode,const struct nls_table * codepage)346 cifs_strndup_from_utf16(const char *src, const int maxlen,
347 const bool is_unicode, const struct nls_table *codepage)
348 {
349 int len;
350 char *dst;
351
352 if (is_unicode) {
353 len = cifs_utf16_bytes((__le16 *) src, maxlen, codepage);
354 len += nls_nullsize(codepage);
355 dst = kmalloc(len, GFP_KERNEL);
356 if (!dst)
357 return NULL;
358 cifs_from_utf16(dst, (__le16 *) src, len, maxlen, codepage,
359 NO_MAP_UNI_RSVD);
360 } else {
361 dst = kstrndup(src, maxlen, GFP_KERNEL);
362 }
363
364 return dst;
365 }
366
convert_to_sfu_char(char src_char)367 static __le16 convert_to_sfu_char(char src_char)
368 {
369 __le16 dest_char;
370
371 switch (src_char) {
372 case ':':
373 dest_char = cpu_to_le16(UNI_COLON);
374 break;
375 case '*':
376 dest_char = cpu_to_le16(UNI_ASTERISK);
377 break;
378 case '?':
379 dest_char = cpu_to_le16(UNI_QUESTION);
380 break;
381 case '<':
382 dest_char = cpu_to_le16(UNI_LESSTHAN);
383 break;
384 case '>':
385 dest_char = cpu_to_le16(UNI_GRTRTHAN);
386 break;
387 case '|':
388 dest_char = cpu_to_le16(UNI_PIPE);
389 break;
390 default:
391 dest_char = 0;
392 }
393
394 return dest_char;
395 }
396
convert_to_sfm_char(char src_char,bool end_of_string)397 static __le16 convert_to_sfm_char(char src_char, bool end_of_string)
398 {
399 __le16 dest_char;
400
401 if (src_char >= 0x01 && src_char <= 0x1F) {
402 dest_char = cpu_to_le16(src_char + 0xF000);
403 return dest_char;
404 }
405 switch (src_char) {
406 case ':':
407 dest_char = cpu_to_le16(SFM_COLON);
408 break;
409 case '"':
410 dest_char = cpu_to_le16(SFM_DOUBLEQUOTE);
411 break;
412 case '*':
413 dest_char = cpu_to_le16(SFM_ASTERISK);
414 break;
415 case '?':
416 dest_char = cpu_to_le16(SFM_QUESTION);
417 break;
418 case '<':
419 dest_char = cpu_to_le16(SFM_LESSTHAN);
420 break;
421 case '>':
422 dest_char = cpu_to_le16(SFM_GRTRTHAN);
423 break;
424 case '|':
425 dest_char = cpu_to_le16(SFM_PIPE);
426 break;
427 case '.':
428 if (end_of_string)
429 dest_char = cpu_to_le16(SFM_PERIOD);
430 else
431 dest_char = 0;
432 break;
433 case ' ':
434 if (end_of_string)
435 dest_char = cpu_to_le16(SFM_SPACE);
436 else
437 dest_char = 0;
438 break;
439 default:
440 dest_char = 0;
441 }
442
443 return dest_char;
444 }
445
446 /*
447 * Convert 16 bit Unicode pathname to wire format from string in current code
448 * page. Conversion may involve remapping up the six characters that are
449 * only legal in POSIX-like OS (if they are present in the string). Path
450 * names are little endian 16 bit Unicode on the wire
451 */
452 int
cifsConvertToUTF16(__le16 * target,const char * source,int srclen,const struct nls_table * cp,int map_chars)453 cifsConvertToUTF16(__le16 *target, const char *source, int srclen,
454 const struct nls_table *cp, int map_chars)
455 {
456 int i, charlen;
457 int j = 0;
458 char src_char;
459 __le16 dst_char;
460 wchar_t tmp;
461 wchar_t *wchar_to; /* UTF-16 */
462 int ret;
463 unicode_t u;
464
465 if (map_chars == NO_MAP_UNI_RSVD)
466 return cifs_strtoUTF16(target, source, PATH_MAX, cp);
467
468 wchar_to = kzalloc(6, GFP_KERNEL);
469
470 for (i = 0; i < srclen; j++) {
471 src_char = source[i];
472 charlen = 1;
473
474 /* check if end of string */
475 if (src_char == 0)
476 goto ctoUTF16_out;
477
478 /* see if we must remap this char */
479 if (map_chars == SFU_MAP_UNI_RSVD)
480 dst_char = convert_to_sfu_char(src_char);
481 else if (map_chars == SFM_MAP_UNI_RSVD) {
482 bool end_of_string;
483
484 /**
485 * Remap spaces and periods found at the end of every
486 * component of the path. The special cases of '.' and
487 * '..' are need to be handled because of symlinks.
488 * They are treated as non-end-of-string to avoid
489 * remapping and breaking symlinks pointing to . or ..
490 **/
491 if ((i == 0 || source[i-1] == '\\') &&
492 source[i] == '.' &&
493 (i == srclen-1 || source[i+1] == '\\'))
494 end_of_string = false; /* "." case */
495 else if (i >= 1 &&
496 (i == 1 || source[i-2] == '\\') &&
497 source[i-1] == '.' &&
498 source[i] == '.' &&
499 (i == srclen-1 || source[i+1] == '\\'))
500 end_of_string = false; /* ".." case */
501 else if ((i == srclen - 1) || (source[i+1] == '\\'))
502 end_of_string = true;
503 else
504 end_of_string = false;
505
506 dst_char = convert_to_sfm_char(src_char, end_of_string);
507 } else
508 dst_char = 0;
509 /*
510 * FIXME: We can not handle remapping backslash (UNI_SLASH)
511 * until all the calls to build_path_from_dentry are modified,
512 * as they use backslash as separator.
513 */
514 if (dst_char == 0) {
515 charlen = cp->char2uni(source + i, srclen - i, &tmp);
516 dst_char = cpu_to_le16(tmp);
517
518 /*
519 * if no match, use question mark, which at least in
520 * some cases serves as wild card
521 */
522 if (charlen > 0)
523 goto ctoUTF16;
524
525 /* convert SURROGATE_PAIR */
526 if (strcmp(cp->charset, "utf8") || !wchar_to)
527 goto unknown;
528 if (*(source + i) & 0x80) {
529 charlen = utf8_to_utf32(source + i, 6, &u);
530 if (charlen < 0)
531 goto unknown;
532 } else
533 goto unknown;
534 ret = utf8s_to_utf16s(source + i, charlen,
535 UTF16_LITTLE_ENDIAN,
536 wchar_to, 6);
537 if (ret < 0)
538 goto unknown;
539
540 i += charlen;
541 dst_char = cpu_to_le16(*wchar_to);
542 if (charlen <= 3)
543 /* 1-3bytes UTF-8 to 2bytes UTF-16 */
544 put_unaligned(dst_char, &target[j]);
545 else if (charlen == 4) {
546 /* 4bytes UTF-8(surrogate pair) to 4bytes UTF-16
547 * 7-8bytes UTF-8(IVS) divided to 2 UTF-16
548 * (charlen=3+4 or 4+4) */
549 put_unaligned(dst_char, &target[j]);
550 dst_char = cpu_to_le16(*(wchar_to + 1));
551 j++;
552 put_unaligned(dst_char, &target[j]);
553 } else if (charlen >= 5) {
554 /* 5-6bytes UTF-8 to 6bytes UTF-16 */
555 put_unaligned(dst_char, &target[j]);
556 dst_char = cpu_to_le16(*(wchar_to + 1));
557 j++;
558 put_unaligned(dst_char, &target[j]);
559 dst_char = cpu_to_le16(*(wchar_to + 2));
560 j++;
561 put_unaligned(dst_char, &target[j]);
562 }
563 continue;
564
565 unknown:
566 dst_char = cpu_to_le16(0x003f);
567 charlen = 1;
568 }
569
570 ctoUTF16:
571 /*
572 * character may take more than one byte in the source string,
573 * but will take exactly two bytes in the target string
574 */
575 i += charlen;
576 put_unaligned(dst_char, &target[j]);
577 }
578
579 ctoUTF16_out:
580 put_unaligned(0, &target[j]); /* Null terminate target unicode string */
581 kfree(wchar_to);
582 return j;
583 }
584
585 /*
586 * cifs_local_to_utf16_bytes - how long will a string be after conversion?
587 * @from - pointer to input string
588 * @maxbytes - don't go past this many bytes of input string
589 * @codepage - source codepage
590 *
591 * Walk a string and return the number of bytes that the string will
592 * be after being converted to the given charset, not including any null
593 * termination required. Don't walk past maxbytes in the source buffer.
594 */
595
596 static int
cifs_local_to_utf16_bytes(const char * from,int len,const struct nls_table * codepage)597 cifs_local_to_utf16_bytes(const char *from, int len,
598 const struct nls_table *codepage)
599 {
600 int charlen;
601 int i;
602 wchar_t wchar_to;
603
604 for (i = 0; len && *from; i++, from += charlen, len -= charlen) {
605 charlen = codepage->char2uni(from, len, &wchar_to);
606 /* Failed conversion defaults to a question mark */
607 if (charlen < 1)
608 charlen = 1;
609 }
610 return 2 * i; /* UTF16 characters are two bytes */
611 }
612
613 /*
614 * cifs_strndup_to_utf16 - copy a string to wire format from the local codepage
615 * @src - source string
616 * @maxlen - don't walk past this many bytes in the source string
617 * @utf16_len - the length of the allocated string in bytes (including null)
618 * @cp - source codepage
619 * @remap - map special chars
620 *
621 * Take a string convert it from the local codepage to UTF16 and
622 * put it in a new buffer. Returns a pointer to the new string or NULL on
623 * error.
624 */
625 __le16 *
cifs_strndup_to_utf16(const char * src,const int maxlen,int * utf16_len,const struct nls_table * cp,int remap)626 cifs_strndup_to_utf16(const char *src, const int maxlen, int *utf16_len,
627 const struct nls_table *cp, int remap)
628 {
629 int len;
630 __le16 *dst;
631
632 len = cifs_local_to_utf16_bytes(src, maxlen, cp);
633 len += 2; /* NULL */
634 dst = kmalloc(len, GFP_KERNEL);
635 if (!dst) {
636 *utf16_len = 0;
637 return NULL;
638 }
639 cifsConvertToUTF16(dst, src, strlen(src), cp, remap);
640 *utf16_len = len;
641 return dst;
642 }
643