fs/cifs/cifs_unicode.c

   1 // SPDX-License-Identifier: GPL-2.0-or-later
   2 /*
   3  *   fs/cifs/cifs_unicode.c
   4  *
   5  *   Copyright (c) International Business Machines  Corp., 2000,2009
   6  *   Modified by Steve French (sfrench@us.ibm.com)
   7  */
   8 #include <linux/fs.h>
   9 #include <linux/slab.h>
  10 #include "cifs_fs_sb.h"
  11 #include "cifs_unicode.h"
  12 #include "cifs_uniupr.h"
  13 #include "cifspdu.h"
  14 #include "cifsglob.h"
  15 #include "cifs_debug.h"
  16
  17 int cifs_remap(struct cifs_sb_info *cifs_sb)
  18 {
  19         int map_type;
  20
  21         if (cifs_sb->mnt_cifs_flags & CIFS_MOUNT_MAP_SFM_CHR)
  22                 map_type = SFM_MAP_UNI_RSVD;
  23         else if (cifs_sb->mnt_cifs_flags & CIFS_MOUNT_MAP_SPECIAL_CHR)
  24                 map_type = SFU_MAP_UNI_RSVD;
  25         else
  26                 map_type = NO_MAP_UNI_RSVD;
  27
  28         return map_type;
  29 }
  30
  31 /* Convert character using the SFU - "Services for Unix" remapping range */
  32 static bool
  33 convert_sfu_char(const __u16 src_char, char *target)
  34 {
  35         /*
  36          * BB: Cannot handle remapping UNI_SLASH until all the calls to
  37          *     build_path_from_dentry are modified, as they use slash as
  38          *     separator.
  39          */
  40         switch (src_char) {
  41         case UNI_COLON:
  42                 *target = ':';
  43                 break;
  44         case UNI_ASTERISK:
  45                 *target = '*';
  46                 break;
  47         case UNI_QUESTION:
  48                 *target = '?';
  49                 break;
  50         case UNI_PIPE:
  51                 *target = '|';
  52                 break;
  53         case UNI_GRTRTHAN:
  54                 *target = '>';
  55                 break;
  56         case UNI_LESSTHAN:
  57                 *target = '<';
  58                 break;
  59         default:
  60                 return false;
  61         }
  62         return true;
  63 }
  64
  65 /* Convert character using the SFM - "Services for Mac" remapping range */
  66 static bool
  67 convert_sfm_char(const __u16 src_char, char *target)
  68 {
  69         if (src_char >= 0xF001 && src_char <= 0xF01F) {
  70                 *target = src_char - 0xF000;
  71                 return true;
  72         }
  73         switch (src_char) {
  74         case SFM_COLON:
  75                 *target = ':';
  76                 break;
  77         case SFM_DOUBLEQUOTE:
  78                 *target = '"';
  79                 break;
  80         case SFM_ASTERISK:
  81                 *target = '*';
  82                 break;
  83         case SFM_QUESTION:
  84                 *target = '?';
  85                 break;
  86         case SFM_PIPE:
  87                 *target = '|';
  88                 break;
  89         case SFM_GRTRTHAN:
  90                 *target = '>';
  91                 break;
  92         case SFM_LESSTHAN:
  93                 *target = '<';
  94                 break;
  95         case SFM_SPACE:
  96                 *target = ' ';
  97                 break;
  98         case SFM_PERIOD:
  99                 *target = '.';
 100                 break;
 101         default:
 102                 return false;
 103         }
 104         return true;
 105 }
 106
 107
 108 /*
 109  * cifs_mapchar - convert a host-endian char to proper char in codepage
 110  * @target - where converted character should be copied
 111  * @src_char - 2 byte host-endian source character
 112  * @cp - codepage to which character should be converted
 113  * @map_type - How should the 7 NTFS/SMB reserved characters be mapped to UCS2?
 114  *
 115  * This function handles the conversion of a single character. It is the
 116  * responsibility of the caller to ensure that the target buffer is large
 117  * enough to hold the result of the conversion (at least NLS_MAX_CHARSET_SIZE).
 118  */
 119 static int
 120 cifs_mapchar(char *target, const __u16 *from, const struct nls_table *cp,
 121              int maptype)
 122 {
 123         int len = 1;
 124         __u16 src_char;
 125
 126         src_char = *from;
 127
 128         if ((maptype == SFM_MAP_UNI_RSVD) && convert_sfm_char(src_char, target))
 129                 return len;
 130         else if ((maptype == SFU_MAP_UNI_RSVD) &&
 131                   convert_sfu_char(src_char, target))
 132                 return len;
 133
 134         /* if character not one of seven in special remap set */
 135         len = cp->uni2char(src_char, target, NLS_MAX_CHARSET_SIZE);
 136         if (len <= 0)
 137                 goto surrogate_pair;
 138
 139         return len;
 140
 141 surrogate_pair:
 142         /* convert SURROGATE_PAIR and IVS */
 143         if (strcmp(cp->charset, "utf8"))
 144                 goto unknown;
 145         len = utf16s_to_utf8s(from, 3, UTF16_LITTLE_ENDIAN, target, 6);
 146         if (len <= 0)
 147                 goto unknown;
 148         return len;
 149
 150 unknown:
 151         *target = '?';
 152         len = 1;
 153         return len;
 154 }
 155
 156 /*
 157  * cifs_from_utf16 - convert utf16le string to local charset
 158  * @to - destination buffer
 159  * @from - source buffer
 160  * @tolen - destination buffer size (in bytes)
 161  * @fromlen - source buffer size (in bytes)
 162  * @codepage - codepage to which characters should be converted
 163  * @mapchar - should characters be remapped according to the mapchars option?
 164  *
 165  * Convert a little-endian utf16le string (as sent by the server) to a string
 166  * in the provided codepage. The tolen and fromlen parameters are to ensure
 167  * that the code doesn't walk off of the end of the buffer (which is always
 168  * a danger if the alignment of the source buffer is off). The destination
 169  * string is always properly null terminated and fits in the destination
 170  * buffer. Returns the length of the destination string in bytes (including
 171  * null terminator).
 172  *
 173  * Note that some windows versions actually send multiword UTF-16 characters
 174  * instead of straight UTF16-2. The linux nls routines however aren't able to
 175  * deal with those characters properly. In the event that we get some of
 176  * those characters, they won't be translated properly.
 177  */
 178 int
 179 cifs_from_utf16(char *to, const __le16 *from, int tolen, int fromlen,
 180                 const struct nls_table *codepage, int map_type)
 181 {
 182         int i, charlen, safelen;
 183         int outlen = 0;
 184         int nullsize = nls_nullsize(codepage);
 185         int fromwords = fromlen / 2;
 186         char tmp[NLS_MAX_CHARSET_SIZE];
 187         __u16 ftmp[3];          /* ftmp[3] = 3array x 2bytes = 6bytes UTF-16 */
 188
 189         /*
 190          * because the chars can be of varying widths, we need to take care
 191          * not to overflow the destination buffer when we get close to the
 192          * end of it. Until we get to this offset, we don't need to check
 193          * for overflow however.
 194          */
 195         safelen = tolen - (NLS_MAX_CHARSET_SIZE + nullsize);
 196
 197         for (i = 0; i < fromwords; i++) {
 198                 ftmp[0] = get_unaligned_le16(&from[i]);
 199                 if (ftmp[0] == 0)
 200                         break;
 201                 if (i + 1 < fromwords)
 202                         ftmp[1] = get_unaligned_le16(&from[i + 1]);
 203                 else
 204                         ftmp[1] = 0;
 205                 if (i + 2 < fromwords)
 206                         ftmp[2] = get_unaligned_le16(&from[i + 2]);
 207                 else
 208                         ftmp[2] = 0;
 209
 210                 /*
 211                  * check to see if converting this character might make the
 212                  * conversion bleed into the null terminator
 213                  */
 214                 if (outlen >= safelen) {
 215                         charlen = cifs_mapchar(tmp, ftmp, codepage, map_type);
 216                         if ((outlen + charlen) > (tolen - nullsize))
 217                                 break;
 218                 }
 219
 220                 /* put converted char into 'to' buffer */
 221                 charlen = cifs_mapchar(&to[outlen], ftmp, codepage, map_type);
 222                 outlen += charlen;
 223
 224                 /* charlen (=bytes of UTF-8 for 1 character)
 225                  * 4bytes UTF-8(surrogate pair) is charlen=4
 226                  *   (4bytes UTF-16 code)
 227                  * 7-8bytes UTF-8(IVS) is charlen=3+4 or 4+4
 228                  *   (2 UTF-8 pairs divided to 2 UTF-16 pairs) */
 229                 if (charlen == 4)
 230                         i++;
 231                 else if (charlen >= 5)
 232                         /* 5-6bytes UTF-8 */
 233                         i += 2;
 234         }
 235
 236         /* properly null-terminate string */
 237         for (i = 0; i < nullsize; i++)
 238                 to[outlen++] = 0;
 239
 240         return outlen;
 241 }
 242
 243 /*
 244  * NAME:        cifs_strtoUTF16()
 245  *
 246  * FUNCTION:    Convert character string to unicode string
 247  *
 248  */
 249 int
 250 cifs_strtoUTF16(__le16 *to, const char *from, int len,
 251               const struct nls_table *codepage)
 252 {
 253         int charlen;
 254         int i;
 255         wchar_t wchar_to; /* needed to quiet sparse */
 256
 257         /* special case for utf8 to handle no plane0 chars */
 258         if (!strcmp(codepage->charset, "utf8")) {
 259                 /*
 260                  * convert utf8 -> utf16, we assume we have enough space
 261                  * as caller should have assumed conversion does not overflow
 262                  * in destination len is length in wchar_t units (16bits)
 263                  */
 264                 i  = utf8s_to_utf16s(from, len, UTF16_LITTLE_ENDIAN,
 265                                        (wchar_t *) to, len);
 266
 267                 /* if success terminate and exit */
 268                 if (i >= 0)
 269                         goto success;
 270                 /*
 271                  * if fails fall back to UCS encoding as this
 272                  * function should not return negative values
 273                  * currently can fail only if source contains
 274                  * invalid encoded characters
 275                  */
 276         }
 277
 278         for (i = 0; len && *from; i++, from += charlen, len -= charlen) {
 279                 charlen = codepage->char2uni(from, len, &wchar_to);
 280                 if (charlen < 1) {
 281                         cifs_dbg(VFS, "strtoUTF16: char2uni of 0x%x returned %d\n",
 282                                  *from, charlen);
 283                         /* A question mark */
 284                         wchar_to = 0x003f;
 285                         charlen = 1;
 286                 }
 287                 put_unaligned_le16(wchar_to, &to[i]);
 288         }
 289
 290 success:
 291         put_unaligned_le16(0, &to[i]);
 292         return i;
 293 }
 294
 295 /*
 296  * cifs_utf16_bytes - how long will a string be after conversion?
 297  * @utf16 - pointer to input string
 298  * @maxbytes - don't go past this many bytes of input string
 299  * @codepage - destination codepage
 300  *
 301  * Walk a utf16le string and return the number of bytes that the string will
 302  * be after being converted to the given charset, not including any null
 303  * termination required. Don't walk past maxbytes in the source buffer.
 304  */
 305 int
 306 cifs_utf16_bytes(const __le16 *from, int maxbytes,
 307                 const struct nls_table *codepage)
 308 {
 309         int i;
 310         int charlen, outlen = 0;
 311         int maxwords = maxbytes / 2;
 312         char tmp[NLS_MAX_CHARSET_SIZE];
 313         __u16 ftmp[3];
 314
 315         for (i = 0; i < maxwords; i++) {
 316                 ftmp[0] = get_unaligned_le16(&from[i]);
 317                 if (ftmp[0] == 0)
 318                         break;
 319                 if (i + 1 < maxwords)
 320                         ftmp[1] = get_unaligned_le16(&from[i + 1]);
 321                 else
 322                         ftmp[1] = 0;
 323                 if (i + 2 < maxwords)
 324                         ftmp[2] = get_unaligned_le16(&from[i + 2]);
 325                 else
 326                         ftmp[2] = 0;
 327
 328                 charlen = cifs_mapchar(tmp, ftmp, codepage, NO_MAP_UNI_RSVD);
 329                 outlen += charlen;
 330         }
 331
 332         return outlen;
 333 }
 334
 335 /*
 336  * cifs_strndup_from_utf16 - copy a string from wire format to the local
 337  * codepage
 338  * @src - source string
 339  * @maxlen - don't walk past this many bytes in the source string
 340  * @is_unicode - is this a unicode string?
 341  * @codepage - destination codepage
 342  *
 343  * Take a string given by the server, convert it to the local codepage and
 344  * put it in a new buffer. Returns a pointer to the new string or NULL on
 345  * error.
 346  */
 347 char *
 348 cifs_strndup_from_utf16(const char *src, const int maxlen,
 349                         const bool is_unicode, const struct nls_table *codepage)
 350 {
 351         int len;
 352         char *dst;
 353
 354         if (is_unicode) {
 355                 len = cifs_utf16_bytes((__le16 *) src, maxlen, codepage);
 356                 len += nls_nullsize(codepage);
 357                 dst = kmalloc(len, GFP_KERNEL);
 358                 if (!dst)
 359                         return NULL;
 360                 cifs_from_utf16(dst, (__le16 *) src, len, maxlen, codepage,
 361                                NO_MAP_UNI_RSVD);
 362         } else {
 363                 len = strnlen(src, maxlen);
 364                 len++;
 365                 dst = kmalloc(len, GFP_KERNEL);
 366                 if (!dst)
 367                         return NULL;
 368                 strlcpy(dst, src, len);
 369         }
 370
 371         return dst;
 372 }
 373
 374 static __le16 convert_to_sfu_char(char src_char)
 375 {
 376         __le16 dest_char;
 377
 378         switch (src_char) {
 379         case ':':
 380                 dest_char = cpu_to_le16(UNI_COLON);
 381                 break;
 382         case '*':
 383                 dest_char = cpu_to_le16(UNI_ASTERISK);
 384                 break;
 385         case '?':
 386                 dest_char = cpu_to_le16(UNI_QUESTION);
 387                 break;
 388         case '<':
 389                 dest_char = cpu_to_le16(UNI_LESSTHAN);
 390                 break;
 391         case '>':
 392                 dest_char = cpu_to_le16(UNI_GRTRTHAN);
 393                 break;
 394         case '|':
 395                 dest_char = cpu_to_le16(UNI_PIPE);
 396                 break;
 397         default:
 398                 dest_char = 0;
 399         }
 400
 401         return dest_char;
 402 }
 403
 404 static __le16 convert_to_sfm_char(char src_char, bool end_of_string)
 405 {
 406         __le16 dest_char;
 407
 408         if (src_char >= 0x01 && src_char <= 0x1F) {
 409                 dest_char = cpu_to_le16(src_char + 0xF000);
 410                 return dest_char;
 411         }
 412         switch (src_char) {
 413         case ':':
 414                 dest_char = cpu_to_le16(SFM_COLON);
 415                 break;
 416         case '"':
 417                 dest_char = cpu_to_le16(SFM_DOUBLEQUOTE);
 418                 break;
 419         case '*':
 420                 dest_char = cpu_to_le16(SFM_ASTERISK);
 421                 break;
 422         case '?':
 423                 dest_char = cpu_to_le16(SFM_QUESTION);
 424                 break;
 425         case '<':
 426                 dest_char = cpu_to_le16(SFM_LESSTHAN);
 427                 break;
 428         case '>':
 429                 dest_char = cpu_to_le16(SFM_GRTRTHAN);
 430                 break;
 431         case '|':
 432                 dest_char = cpu_to_le16(SFM_PIPE);
 433                 break;
 434         case '.':
 435                 if (end_of_string)
 436                         dest_char = cpu_to_le16(SFM_PERIOD);
 437                 else
 438                         dest_char = 0;
 439                 break;
 440         case ' ':
 441                 if (end_of_string)
 442                         dest_char = cpu_to_le16(SFM_SPACE);
 443                 else
 444                         dest_char = 0;
 445                 break;
 446         default:
 447                 dest_char = 0;
 448         }
 449
 450         return dest_char;
 451 }
 452
 453 /*
 454  * Convert 16 bit Unicode pathname to wire format from string in current code
 455  * page. Conversion may involve remapping up the six characters that are
 456  * only legal in POSIX-like OS (if they are present in the string). Path
 457  * names are little endian 16 bit Unicode on the wire
 458  */
 459 int
 460 cifsConvertToUTF16(__le16 *target, const char *source, int srclen,
 461                  const struct nls_table *cp, int map_chars)
 462 {
 463         int i, charlen;
 464         int j = 0;
 465         char src_char;
 466         __le16 dst_char;
 467         wchar_t tmp;
 468         wchar_t *wchar_to;      /* UTF-16 */
 469         int ret;
 470         unicode_t u;
 471
 472         if (map_chars == NO_MAP_UNI_RSVD)
 473                 return cifs_strtoUTF16(target, source, PATH_MAX, cp);
 474
 475         wchar_to = kzalloc(6, GFP_KERNEL);
 476
 477         for (i = 0; i < srclen; j++) {
 478                 src_char = source[i];
 479                 charlen = 1;
 480
 481                 /* check if end of string */
 482                 if (src_char == 0)
 483                         goto ctoUTF16_out;
 484
 485                 /* see if we must remap this char */
 486                 if (map_chars == SFU_MAP_UNI_RSVD)
 487                         dst_char = convert_to_sfu_char(src_char);
 488                 else if (map_chars == SFM_MAP_UNI_RSVD) {
 489                         bool end_of_string;
 490
 491                         /**
 492                          * Remap spaces and periods found at the end of every
 493                          * component of the path. The special cases of '.' and
 494                          * '..' do not need to be dealt with explicitly because
 495                          * they are addressed in namei.c:link_path_walk().
 496                          **/
 497                         if ((i == srclen - 1) || (source[i+1] == '\\'))
 498                                 end_of_string = true;
 499                         else
 500                                 end_of_string = false;
 501
 502                         dst_char = convert_to_sfm_char(src_char, end_of_string);
 503                 } else
 504                         dst_char = 0;
 505                 /*
 506                  * FIXME: We can not handle remapping backslash (UNI_SLASH)
 507                  * until all the calls to build_path_from_dentry are modified,
 508                  * as they use backslash as separator.
 509                  */
 510                 if (dst_char == 0) {
 511                         charlen = cp->char2uni(source + i, srclen - i, &tmp);
 512                         dst_char = cpu_to_le16(tmp);
 513
 514                         /*
 515                          * if no match, use question mark, which at least in
 516                          * some cases serves as wild card
 517                          */
 518                         if (charlen > 0)
 519                                 goto ctoUTF16;
 520
 521                         /* convert SURROGATE_PAIR */
 522                         if (strcmp(cp->charset, "utf8") || !wchar_to)
 523                                 goto unknown;
 524                         if (*(source + i) & 0x80) {
 525                                 charlen = utf8_to_utf32(source + i, 6, &u);
 526                                 if (charlen < 0)
 527                                         goto unknown;
 528                         } else
 529                                 goto unknown;
 530                         ret  = utf8s_to_utf16s(source + i, charlen,
 531                                                UTF16_LITTLE_ENDIAN,
 532                                                wchar_to, 6);
 533                         if (ret < 0)
 534                                 goto unknown;
 535
 536                         i += charlen;
 537                         dst_char = cpu_to_le16(*wchar_to);
 538                         if (charlen <= 3)
 539                                 /* 1-3bytes UTF-8 to 2bytes UTF-16 */
 540                                 put_unaligned(dst_char, &target[j]);
 541                         else if (charlen == 4) {
 542                                 /* 4bytes UTF-8(surrogate pair) to 4bytes UTF-16
 543                                  * 7-8bytes UTF-8(IVS) divided to 2 UTF-16
 544                                  *   (charlen=3+4 or 4+4) */
 545                                 put_unaligned(dst_char, &target[j]);
 546                                 dst_char = cpu_to_le16(*(wchar_to + 1));
 547                                 j++;
 548                                 put_unaligned(dst_char, &target[j]);
 549                         } else if (charlen >= 5) {
 550                                 /* 5-6bytes UTF-8 to 6bytes UTF-16 */
 551                                 put_unaligned(dst_char, &target[j]);
 552                                 dst_char = cpu_to_le16(*(wchar_to + 1));
 553                                 j++;
 554                                 put_unaligned(dst_char, &target[j]);
 555                                 dst_char = cpu_to_le16(*(wchar_to + 2));
 556                                 j++;
 557                                 put_unaligned(dst_char, &target[j]);
 558                         }
 559                         continue;
 560
 561 unknown:
 562                         dst_char = cpu_to_le16(0x003f);
 563                         charlen = 1;
 564                 }
 565
 566 ctoUTF16:
 567                 /*
 568                  * character may take more than one byte in the source string,
 569                  * but will take exactly two bytes in the target string
 570                  */
 571                 i += charlen;
 572                 put_unaligned(dst_char, &target[j]);
 573         }
 574
 575 ctoUTF16_out:
 576         put_unaligned(0, &target[j]); /* Null terminate target unicode string */
 577         kfree(wchar_to);
 578         return j;
 579 }
 580
 581 /*
 582  * cifs_local_to_utf16_bytes - how long will a string be after conversion?
 583  * @from - pointer to input string
 584  * @maxbytes - don't go past this many bytes of input string
 585  * @codepage - source codepage
 586  *
 587  * Walk a string and return the number of bytes that the string will
 588  * be after being converted to the given charset, not including any null
 589  * termination required. Don't walk past maxbytes in the source buffer.
 590  */
 591
 592 static int
 593 cifs_local_to_utf16_bytes(const char *from, int len,
 594                           const struct nls_table *codepage)
 595 {
 596         int charlen;
 597         int i;
 598         wchar_t wchar_to;
 599
 600         for (i = 0; len && *from; i++, from += charlen, len -= charlen) {
 601                 charlen = codepage->char2uni(from, len, &wchar_to);
 602                 /* Failed conversion defaults to a question mark */
 603                 if (charlen < 1)
 604                         charlen = 1;
 605         }
 606         return 2 * i; /* UTF16 characters are two bytes */
 607 }
 608
 609 /*
 610  * cifs_strndup_to_utf16 - copy a string to wire format from the local codepage
 611  * @src - source string
 612  * @maxlen - don't walk past this many bytes in the source string
 613  * @utf16_len - the length of the allocated string in bytes (including null)
 614  * @cp - source codepage
 615  * @remap - map special chars
 616  *
 617  * Take a string convert it from the local codepage to UTF16 and
 618  * put it in a new buffer. Returns a pointer to the new string or NULL on
 619  * error.
 620  */
 621 __le16 *
 622 cifs_strndup_to_utf16(const char *src, const int maxlen, int *utf16_len,
 623                       const struct nls_table *cp, int remap)
 624 {
 625         int len;
 626         __le16 *dst;
 627
 628         len = cifs_local_to_utf16_bytes(src, maxlen, cp);
 629         len += 2; /* NULL */
 630         dst = kmalloc(len, GFP_KERNEL);
 631         if (!dst) {
 632                 *utf16_len = 0;
 633                 return NULL;
 634         }
 635         cifsConvertToUTF16(dst, src, strlen(src), cp, remap);
 636         *utf16_len = len;
 637         return dst;
 638 }