fs/udf/unicode.c

   1 /*
   2  * unicode.c
   3  *
   4  * PURPOSE
   5  *      Routines for converting between UTF-8 and OSTA Compressed Unicode.
   6  *      Also handles filename mangling
   7  *
   8  * DESCRIPTION
   9  *      OSTA Compressed Unicode is explained in the OSTA UDF specification.
  10  *              http://www.osta.org/
  11  *      UTF-8 is explained in the IETF RFC XXXX.
  12  *              ftp://ftp.internic.net/rfc/rfcxxxx.txt
  13  *
  14  * COPYRIGHT
  15  *      This file is distributed under the terms of the GNU General Public
  16  *      License (GPL). Copies of the GPL can be obtained from:
  17  *              ftp://prep.ai.mit.edu/pub/gnu/GPL
  18  *      Each contributing author retains all rights to their own work.
  19  */
  20
  21 #include "udfdecl.h"
  22
  23 #include <linux/kernel.h>
  24 #include <linux/string.h>       /* for memset */
  25 #include <linux/nls.h>
  26 #include <linux/crc-itu-t.h>
  27 #include <linux/slab.h>
  28
  29 #include "udf_sb.h"
  30
  31 static int udf_translate_to_linux(uint8_t *, int, uint8_t *, int, uint8_t *,
  32                                   int);
  33
  34 static int udf_char_to_ustr(struct ustr *dest, const uint8_t *src, int strlen)
  35 {
  36         if ((!dest) || (!src) || (!strlen) || (strlen > UDF_NAME_LEN - 2))
  37                 return 0;
  38
  39         memset(dest, 0, sizeof(struct ustr));
  40         memcpy(dest->u_name, src, strlen);
  41         dest->u_cmpID = 0x08;
  42         dest->u_len = strlen;
  43
  44         return strlen;
  45 }
  46
  47 /*
  48  * udf_build_ustr
  49  */
  50 int udf_build_ustr(struct ustr *dest, dstring *ptr, int size)
  51 {
  52         int usesize;
  53
  54         if (!dest || !ptr || !size)
  55                 return -1;
  56         BUG_ON(size < 2);
  57
  58         usesize = min_t(size_t, ptr[size - 1], sizeof(dest->u_name));
  59         usesize = min(usesize, size - 2);
  60         dest->u_cmpID = ptr[0];
  61         dest->u_len = usesize;
  62         memcpy(dest->u_name, ptr + 1, usesize);
  63         memset(dest->u_name + usesize, 0, sizeof(dest->u_name) - usesize);
  64
  65         return 0;
  66 }
  67
  68 /*
  69  * udf_build_ustr_exact
  70  */
  71 static int udf_build_ustr_exact(struct ustr *dest, dstring *ptr, int exactsize)
  72 {
  73         if ((!dest) || (!ptr) || (!exactsize))
  74                 return -1;
  75
  76         memset(dest, 0, sizeof(struct ustr));
  77         dest->u_cmpID = ptr[0];
  78         dest->u_len = exactsize - 1;
  79         memcpy(dest->u_name, ptr + 1, exactsize - 1);
  80
  81         return 0;
  82 }
  83
  84 /*
  85  * udf_ocu_to_utf8
  86  *
  87  * PURPOSE
  88  *      Convert OSTA Compressed Unicode to the UTF-8 equivalent.
  89  *
  90  * PRE-CONDITIONS
  91  *      utf                     Pointer to UTF-8 output buffer.
  92  *      ocu                     Pointer to OSTA Compressed Unicode input buffer
  93  *                              of size UDF_NAME_LEN bytes.
  94  *                              both of type "struct ustr *"
  95  *
  96  * POST-CONDITIONS
  97  *      <return>                Zero on success.
  98  *
  99  * HISTORY
 100  *      November 12, 1997 - Andrew E. Mileski
 101  *      Written, tested, and released.
 102  */
 103 int udf_CS0toUTF8(struct ustr *utf_o, const struct ustr *ocu_i)
 104 {
 105         const uint8_t *ocu;
 106         uint8_t cmp_id, ocu_len;
 107         int i;
 108
 109         ocu_len = ocu_i->u_len;
 110         if (ocu_len == 0) {
 111                 memset(utf_o, 0, sizeof(struct ustr));
 112                 return 0;
 113         }
 114
 115         cmp_id = ocu_i->u_cmpID;
 116         if (cmp_id != 8 && cmp_id != 16) {
 117                 memset(utf_o, 0, sizeof(struct ustr));
 118                 pr_err("unknown compression code (%d) stri=%s\n",
 119                        cmp_id, ocu_i->u_name);
 120                 return 0;
 121         }
 122
 123         ocu = ocu_i->u_name;
 124         utf_o->u_len = 0;
 125         for (i = 0; (i < ocu_len) && (utf_o->u_len <= (UDF_NAME_LEN - 3));) {
 126
 127                 /* Expand OSTA compressed Unicode to Unicode */
 128                 uint32_t c = ocu[i++];
 129                 if (cmp_id == 16)
 130                         c = (c << 8) | ocu[i++];
 131
 132                 /* Compress Unicode to UTF-8 */
 133                 if (c < 0x80U)
 134                         utf_o->u_name[utf_o->u_len++] = (uint8_t)c;
 135                 else if (c < 0x800U) {
 136                         utf_o->u_name[utf_o->u_len++] =
 137                                                 (uint8_t)(0xc0 | (c >> 6));
 138                         utf_o->u_name[utf_o->u_len++] =
 139                                                 (uint8_t)(0x80 | (c & 0x3f));
 140                 } else {
 141                         utf_o->u_name[utf_o->u_len++] =
 142                                                 (uint8_t)(0xe0 | (c >> 12));
 143                         utf_o->u_name[utf_o->u_len++] =
 144                                                 (uint8_t)(0x80 |
 145                                                           ((c >> 6) & 0x3f));
 146                         utf_o->u_name[utf_o->u_len++] =
 147                                                 (uint8_t)(0x80 | (c & 0x3f));
 148                 }
 149         }
 150         utf_o->u_cmpID = 8;
 151
 152         return utf_o->u_len;
 153 }
 154
 155 /*
 156  *
 157  * udf_utf8_to_ocu
 158  *
 159  * PURPOSE
 160  *      Convert UTF-8 to the OSTA Compressed Unicode equivalent.
 161  *
 162  * DESCRIPTION
 163  *      This routine is only called by udf_lookup().
 164  *
 165  * PRE-CONDITIONS
 166  *      ocu                     Pointer to OSTA Compressed Unicode output
 167  *                              buffer of size UDF_NAME_LEN bytes.
 168  *      utf                     Pointer to UTF-8 input buffer.
 169  *      utf_len                 Length of UTF-8 input buffer in bytes.
 170  *
 171  * POST-CONDITIONS
 172  *      <return>                Zero on success.
 173  *
 174  * HISTORY
 175  *      November 12, 1997 - Andrew E. Mileski
 176  *      Written, tested, and released.
 177  */
 178 static int udf_UTF8toCS0(dstring *ocu, struct ustr *utf, int length)
 179 {
 180         unsigned c, i, max_val, utf_char;
 181         int utf_cnt, u_len;
 182
 183         memset(ocu, 0, sizeof(dstring) * length);
 184         ocu[0] = 8;
 185         max_val = 0xffU;
 186
 187 try_again:
 188         u_len = 0U;
 189         utf_char = 0U;
 190         utf_cnt = 0U;
 191         for (i = 0U; i < utf->u_len; i++) {
 192                 c = (uint8_t)utf->u_name[i];
 193
 194                 /* Complete a multi-byte UTF-8 character */
 195                 if (utf_cnt) {
 196                         utf_char = (utf_char << 6) | (c & 0x3fU);
 197                         if (--utf_cnt)
 198                                 continue;
 199                 } else {
 200                         /* Check for a multi-byte UTF-8 character */
 201                         if (c & 0x80U) {
 202                                 /* Start a multi-byte UTF-8 character */
 203                                 if ((c & 0xe0U) == 0xc0U) {
 204                                         utf_char = c & 0x1fU;
 205                                         utf_cnt = 1;
 206                                 } else if ((c & 0xf0U) == 0xe0U) {
 207                                         utf_char = c & 0x0fU;
 208                                         utf_cnt = 2;
 209                                 } else if ((c & 0xf8U) == 0xf0U) {
 210                                         utf_char = c & 0x07U;
 211                                         utf_cnt = 3;
 212                                 } else if ((c & 0xfcU) == 0xf8U) {
 213                                         utf_char = c & 0x03U;
 214                                         utf_cnt = 4;
 215                                 } else if ((c & 0xfeU) == 0xfcU) {
 216                                         utf_char = c & 0x01U;
 217                                         utf_cnt = 5;
 218                                 } else {
 219                                         goto error_out;
 220                                 }
 221                                 continue;
 222                         } else {
 223                                 /* Single byte UTF-8 character (most common) */
 224                                 utf_char = c;
 225                         }
 226                 }
 227
 228                 /* Choose no compression if necessary */
 229                 if (utf_char > max_val) {
 230                         if (max_val == 0xffU) {
 231                                 max_val = 0xffffU;
 232                                 ocu[0] = (uint8_t)0x10U;
 233                                 goto try_again;
 234                         }
 235                         goto error_out;
 236                 }
 237
 238                 if (max_val == 0xffffU)
 239                         ocu[++u_len] = (uint8_t)(utf_char >> 8);
 240                 ocu[++u_len] = (uint8_t)(utf_char & 0xffU);
 241         }
 242
 243         if (utf_cnt) {
 244 error_out:
 245                 ocu[++u_len] = '?';
 246                 printk(KERN_DEBUG pr_fmt("bad UTF-8 character\n"));
 247         }
 248
 249         ocu[length - 1] = (uint8_t)u_len + 1;
 250
 251         return u_len + 1;
 252 }
 253
 254 static int udf_CS0toNLS(struct nls_table *nls, struct ustr *utf_o,
 255                         const struct ustr *ocu_i)
 256 {
 257         const uint8_t *ocu;
 258         uint8_t cmp_id, ocu_len;
 259         int i, len;
 260
 261
 262         ocu_len = ocu_i->u_len;
 263         if (ocu_len == 0) {
 264                 memset(utf_o, 0, sizeof(struct ustr));
 265                 return 0;
 266         }
 267
 268         cmp_id = ocu_i->u_cmpID;
 269         if (cmp_id != 8 && cmp_id != 16) {
 270                 memset(utf_o, 0, sizeof(struct ustr));
 271                 pr_err("unknown compression code (%d) stri=%s\n",
 272                        cmp_id, ocu_i->u_name);
 273                 return 0;
 274         }
 275
 276         ocu = ocu_i->u_name;
 277         utf_o->u_len = 0;
 278         for (i = 0; (i < ocu_len) && (utf_o->u_len <= (UDF_NAME_LEN - 3));) {
 279                 /* Expand OSTA compressed Unicode to Unicode */
 280                 uint32_t c = ocu[i++];
 281                 if (cmp_id == 16)
 282                         c = (c << 8) | ocu[i++];
 283
 284                 len = nls->uni2char(c, &utf_o->u_name[utf_o->u_len],
 285                                     UDF_NAME_LEN - utf_o->u_len);
 286                 /* Valid character? */
 287                 if (len >= 0)
 288                         utf_o->u_len += len;
 289                 else
 290                         utf_o->u_name[utf_o->u_len++] = '?';
 291         }
 292         utf_o->u_cmpID = 8;
 293
 294         return utf_o->u_len;
 295 }
 296
 297 static int udf_NLStoCS0(struct nls_table *nls, dstring *ocu, struct ustr *uni,
 298                         int length)
 299 {
 300         int len;
 301         unsigned i, max_val;
 302         uint16_t uni_char;
 303         int u_len;
 304
 305         memset(ocu, 0, sizeof(dstring) * length);
 306         ocu[0] = 8;
 307         max_val = 0xffU;
 308
 309 try_again:
 310         u_len = 0U;
 311         for (i = 0U; i < uni->u_len; i++) {
 312                 len = nls->char2uni(&uni->u_name[i], uni->u_len - i, &uni_char);
 313                 if (!len)
 314                         continue;
 315                 /* Invalid character, deal with it */
 316                 if (len < 0) {
 317                         len = 1;
 318                         uni_char = '?';
 319                 }
 320
 321                 if (uni_char > max_val) {
 322                         max_val = 0xffffU;
 323                         ocu[0] = (uint8_t)0x10U;
 324                         goto try_again;
 325                 }
 326
 327                 if (max_val == 0xffffU)
 328                         ocu[++u_len] = (uint8_t)(uni_char >> 8);
 329                 ocu[++u_len] = (uint8_t)(uni_char & 0xffU);
 330                 i += len - 1;
 331         }
 332
 333         ocu[length - 1] = (uint8_t)u_len + 1;
 334         return u_len + 1;
 335 }
 336
 337 int udf_get_filename(struct super_block *sb, uint8_t *sname, int slen,
 338                      uint8_t *dname, int dlen)
 339 {
 340         struct ustr *filename, *unifilename;
 341         int len = 0;
 342
 343         filename = kmalloc(sizeof(struct ustr), GFP_NOFS);
 344         if (!filename)
 345                 return 0;
 346
 347         unifilename = kmalloc(sizeof(struct ustr), GFP_NOFS);
 348         if (!unifilename)
 349                 goto out1;
 350
 351         if (udf_build_ustr_exact(unifilename, sname, slen))
 352                 goto out2;
 353
 354         if (UDF_QUERY_FLAG(sb, UDF_FLAG_UTF8)) {
 355                 if (!udf_CS0toUTF8(filename, unifilename)) {
 356                         udf_debug("Failed in udf_get_filename: sname = %s\n",
 357                                   sname);
 358                         goto out2;
 359                 }
 360         } else if (UDF_QUERY_FLAG(sb, UDF_FLAG_NLS_MAP)) {
 361                 if (!udf_CS0toNLS(UDF_SB(sb)->s_nls_map, filename,
 362                                   unifilename)) {
 363                         udf_debug("Failed in udf_get_filename: sname = %s\n",
 364                                   sname);
 365                         goto out2;
 366                 }
 367         } else
 368                 goto out2;
 369
 370         len = udf_translate_to_linux(dname, dlen,
 371                                      filename->u_name, filename->u_len,
 372                                      unifilename->u_name, unifilename->u_len);
 373 out2:
 374         kfree(unifilename);
 375 out1:
 376         kfree(filename);
 377         return len;
 378 }
 379
 380 int udf_put_filename(struct super_block *sb, const uint8_t *sname,
 381                      uint8_t *dname, int flen)
 382 {
 383         struct ustr unifilename;
 384         int namelen;
 385
 386         if (!udf_char_to_ustr(&unifilename, sname, flen))
 387                 return 0;
 388
 389         if (UDF_QUERY_FLAG(sb, UDF_FLAG_UTF8)) {
 390                 namelen = udf_UTF8toCS0(dname, &unifilename, UDF_NAME_LEN);
 391                 if (!namelen)
 392                         return 0;
 393         } else if (UDF_QUERY_FLAG(sb, UDF_FLAG_NLS_MAP)) {
 394                 namelen = udf_NLStoCS0(UDF_SB(sb)->s_nls_map, dname,
 395                                         &unifilename, UDF_NAME_LEN);
 396                 if (!namelen)
 397                         return 0;
 398         } else
 399                 return 0;
 400
 401         return namelen;
 402 }
 403
 404 #define ILLEGAL_CHAR_MARK       '_'
 405 #define EXT_MARK                '.'
 406 #define CRC_MARK                '#'
 407 #define EXT_SIZE                5
 408 /* Number of chars we need to store generated CRC to make filename unique */
 409 #define CRC_LEN                 5
 410
 411 static int udf_translate_to_linux(uint8_t *newName, int newLen,
 412                                   uint8_t *udfName, int udfLen,
 413                                   uint8_t *fidName, int fidNameLen)
 414 {
 415         int index, newIndex = 0, needsCRC = 0;
 416         int extIndex = 0, newExtIndex = 0, hasExt = 0;
 417         unsigned short valueCRC;
 418         uint8_t curr;
 419         const uint8_t hexChar[] = "0123456789ABCDEF";
 420
 421         if (udfName[0] == '.' &&
 422             (udfLen == 1 || (udfLen == 2 && udfName[1] == '.'))) {
 423                 needsCRC = 1;
 424                 newIndex = udfLen;
 425                 memcpy(newName, udfName, udfLen);
 426         } else {
 427                 for (index = 0; index < udfLen; index++) {
 428                         curr = udfName[index];
 429                         if (curr == '/' || curr == 0) {
 430                                 needsCRC = 1;
 431                                 curr = ILLEGAL_CHAR_MARK;
 432                                 while (index + 1 < udfLen &&
 433                                                 (udfName[index + 1] == '/' ||
 434                                                  udfName[index + 1] == 0))
 435                                         index++;
 436                         }
 437                         if (curr == EXT_MARK &&
 438                                         (udfLen - index - 1) <= EXT_SIZE) {
 439                                 if (udfLen == index + 1)
 440                                         hasExt = 0;
 441                                 else {
 442                                         hasExt = 1;
 443                                         extIndex = index;
 444                                         newExtIndex = newIndex;
 445                                 }
 446                         }
 447                         if (newIndex < newLen)
 448                                 newName[newIndex++] = curr;
 449                         else
 450                                 needsCRC = 1;
 451                 }
 452         }
 453         if (needsCRC) {
 454                 uint8_t ext[EXT_SIZE];
 455                 int localExtIndex = 0;
 456
 457                 if (hasExt) {
 458                         int maxFilenameLen;
 459                         for (index = 0;
 460                              index < EXT_SIZE && extIndex + index + 1 < udfLen;
 461                              index++) {
 462                                 curr = udfName[extIndex + index + 1];
 463
 464                                 if (curr == '/' || curr == 0) {
 465                                         needsCRC = 1;
 466                                         curr = ILLEGAL_CHAR_MARK;
 467                                         while (extIndex + index + 2 < udfLen &&
 468                                               (index + 1 < EXT_SIZE &&
 469                                                 (udfName[extIndex + index + 2] == '/' ||
 470                                                  udfName[extIndex + index + 2] == 0)))
 471                                                 index++;
 472                                 }
 473                                 ext[localExtIndex++] = curr;
 474                         }
 475                         maxFilenameLen = newLen - CRC_LEN - localExtIndex;
 476                         if (newIndex > maxFilenameLen)
 477                                 newIndex = maxFilenameLen;
 478                         else
 479                                 newIndex = newExtIndex;
 480                 } else if (newIndex > newLen - CRC_LEN)
 481                         newIndex = newLen - CRC_LEN;
 482                 newName[newIndex++] = CRC_MARK;
 483                 valueCRC = crc_itu_t(0, fidName, fidNameLen);
 484                 newName[newIndex++] = hexChar[(valueCRC & 0xf000) >> 12];
 485                 newName[newIndex++] = hexChar[(valueCRC & 0x0f00) >> 8];
 486                 newName[newIndex++] = hexChar[(valueCRC & 0x00f0) >> 4];
 487                 newName[newIndex++] = hexChar[(valueCRC & 0x000f)];
 488
 489                 if (hasExt) {
 490                         newName[newIndex++] = EXT_MARK;
 491                         for (index = 0; index < localExtIndex; index++)
 492                                 newName[newIndex++] = ext[index];
 493                 }
 494         }
 495
 496         return newIndex;
 497 }