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 void udf_build_ustr_exact(struct ustr *dest, dstring *ptr, int exactsize)
  72 {
  73         memset(dest, 0, sizeof(struct ustr));
  74         dest->u_cmpID = ptr[0];
  75         dest->u_len = exactsize - 1;
  76         memcpy(dest->u_name, ptr + 1, exactsize - 1);
  77 }
  78
  79 /*
  80  * udf_CS0toUTF8
  81  *
  82  * PURPOSE
  83  *      Convert OSTA Compressed Unicode to the UTF-8 equivalent.
  84  *
  85  * PRE-CONDITIONS
  86  *      utf                     Pointer to UTF-8 output buffer.
  87  *      ocu                     Pointer to OSTA Compressed Unicode input buffer
  88  *                              of size UDF_NAME_LEN bytes.
  89  *                              both of type "struct ustr *"
  90  *
  91  * POST-CONDITIONS
  92  *      <return>                >= 0 on success.
  93  *
  94  * HISTORY
  95  *      November 12, 1997 - Andrew E. Mileski
  96  *      Written, tested, and released.
  97  */
  98 int udf_CS0toUTF8(struct ustr *utf_o, const struct ustr *ocu_i)
  99 {
 100         const uint8_t *ocu;
 101         uint8_t cmp_id, ocu_len;
 102         int i;
 103
 104         ocu_len = ocu_i->u_len;
 105         if (ocu_len == 0) {
 106                 memset(utf_o, 0, sizeof(struct ustr));
 107                 return 0;
 108         }
 109
 110         cmp_id = ocu_i->u_cmpID;
 111         if (cmp_id != 8 && cmp_id != 16) {
 112                 memset(utf_o, 0, sizeof(struct ustr));
 113                 pr_err("unknown compression code (%d) stri=%s\n",
 114                        cmp_id, ocu_i->u_name);
 115                 return -EINVAL;
 116         }
 117
 118         ocu = ocu_i->u_name;
 119         utf_o->u_len = 0;
 120         for (i = 0; (i < ocu_len) && (utf_o->u_len <= (UDF_NAME_LEN - 3));) {
 121
 122                 /* Expand OSTA compressed Unicode to Unicode */
 123                 uint32_t c = ocu[i++];
 124                 if (cmp_id == 16)
 125                         c = (c << 8) | ocu[i++];
 126
 127                 /* Compress Unicode to UTF-8 */
 128                 if (c < 0x80U)
 129                         utf_o->u_name[utf_o->u_len++] = (uint8_t)c;
 130                 else if (c < 0x800U) {
 131                         utf_o->u_name[utf_o->u_len++] =
 132                                                 (uint8_t)(0xc0 | (c >> 6));
 133                         utf_o->u_name[utf_o->u_len++] =
 134                                                 (uint8_t)(0x80 | (c & 0x3f));
 135                 } else {
 136                         utf_o->u_name[utf_o->u_len++] =
 137                                                 (uint8_t)(0xe0 | (c >> 12));
 138                         utf_o->u_name[utf_o->u_len++] =
 139                                                 (uint8_t)(0x80 |
 140                                                           ((c >> 6) & 0x3f));
 141                         utf_o->u_name[utf_o->u_len++] =
 142                                                 (uint8_t)(0x80 | (c & 0x3f));
 143                 }
 144         }
 145         utf_o->u_cmpID = 8;
 146
 147         return utf_o->u_len;
 148 }
 149
 150 /*
 151  *
 152  * udf_UTF8toCS0
 153  *
 154  * PURPOSE
 155  *      Convert UTF-8 to the OSTA Compressed Unicode equivalent.
 156  *
 157  * DESCRIPTION
 158  *      This routine is only called by udf_lookup().
 159  *
 160  * PRE-CONDITIONS
 161  *      ocu                     Pointer to OSTA Compressed Unicode output
 162  *                              buffer of size UDF_NAME_LEN bytes.
 163  *      utf                     Pointer to UTF-8 input buffer.
 164  *      utf_len                 Length of UTF-8 input buffer in bytes.
 165  *
 166  * POST-CONDITIONS
 167  *      <return>                Zero on success.
 168  *
 169  * HISTORY
 170  *      November 12, 1997 - Andrew E. Mileski
 171  *      Written, tested, and released.
 172  */
 173 static int udf_UTF8toCS0(dstring *ocu, struct ustr *utf, int length)
 174 {
 175         unsigned c, i, max_val, utf_char;
 176         int utf_cnt, u_len;
 177
 178         memset(ocu, 0, sizeof(dstring) * length);
 179         ocu[0] = 8;
 180         max_val = 0xffU;
 181
 182 try_again:
 183         u_len = 0U;
 184         utf_char = 0U;
 185         utf_cnt = 0U;
 186         for (i = 0U; i < utf->u_len; i++) {
 187                 c = (uint8_t)utf->u_name[i];
 188
 189                 /* Complete a multi-byte UTF-8 character */
 190                 if (utf_cnt) {
 191                         utf_char = (utf_char << 6) | (c & 0x3fU);
 192                         if (--utf_cnt)
 193                                 continue;
 194                 } else {
 195                         /* Check for a multi-byte UTF-8 character */
 196                         if (c & 0x80U) {
 197                                 /* Start a multi-byte UTF-8 character */
 198                                 if ((c & 0xe0U) == 0xc0U) {
 199                                         utf_char = c & 0x1fU;
 200                                         utf_cnt = 1;
 201                                 } else if ((c & 0xf0U) == 0xe0U) {
 202                                         utf_char = c & 0x0fU;
 203                                         utf_cnt = 2;
 204                                 } else if ((c & 0xf8U) == 0xf0U) {
 205                                         utf_char = c & 0x07U;
 206                                         utf_cnt = 3;
 207                                 } else if ((c & 0xfcU) == 0xf8U) {
 208                                         utf_char = c & 0x03U;
 209                                         utf_cnt = 4;
 210                                 } else if ((c & 0xfeU) == 0xfcU) {
 211                                         utf_char = c & 0x01U;
 212                                         utf_cnt = 5;
 213                                 } else {
 214                                         goto error_out;
 215                                 }
 216                                 continue;
 217                         } else {
 218                                 /* Single byte UTF-8 character (most common) */
 219                                 utf_char = c;
 220                         }
 221                 }
 222
 223                 /* Choose no compression if necessary */
 224                 if (utf_char > max_val) {
 225                         if (max_val == 0xffU) {
 226                                 max_val = 0xffffU;
 227                                 ocu[0] = (uint8_t)0x10U;
 228                                 goto try_again;
 229                         }
 230                         goto error_out;
 231                 }
 232
 233                 if (max_val == 0xffffU)
 234                         ocu[++u_len] = (uint8_t)(utf_char >> 8);
 235                 ocu[++u_len] = (uint8_t)(utf_char & 0xffU);
 236         }
 237
 238         if (utf_cnt) {
 239 error_out:
 240                 ocu[++u_len] = '?';
 241                 printk(KERN_DEBUG pr_fmt("bad UTF-8 character\n"));
 242         }
 243
 244         ocu[length - 1] = (uint8_t)u_len + 1;
 245
 246         return u_len + 1;
 247 }
 248
 249 static int udf_CS0toNLS(struct nls_table *nls, struct ustr *utf_o,
 250                         const struct ustr *ocu_i)
 251 {
 252         const uint8_t *ocu;
 253         uint8_t cmp_id, ocu_len;
 254         int i, len;
 255
 256
 257         ocu_len = ocu_i->u_len;
 258         if (ocu_len == 0) {
 259                 memset(utf_o, 0, sizeof(struct ustr));
 260                 return 0;
 261         }
 262
 263         cmp_id = ocu_i->u_cmpID;
 264         if (cmp_id != 8 && cmp_id != 16) {
 265                 memset(utf_o, 0, sizeof(struct ustr));
 266                 pr_err("unknown compression code (%d) stri=%s\n",
 267                        cmp_id, ocu_i->u_name);
 268                 return -EINVAL;
 269         }
 270
 271         ocu = ocu_i->u_name;
 272         utf_o->u_len = 0;
 273         for (i = 0; (i < ocu_len) && (utf_o->u_len <= (UDF_NAME_LEN - 3));) {
 274                 /* Expand OSTA compressed Unicode to Unicode */
 275                 uint32_t c = ocu[i++];
 276                 if (cmp_id == 16)
 277                         c = (c << 8) | ocu[i++];
 278
 279                 len = nls->uni2char(c, &utf_o->u_name[utf_o->u_len],
 280                                     UDF_NAME_LEN - utf_o->u_len);
 281                 /* Valid character? */
 282                 if (len >= 0)
 283                         utf_o->u_len += len;
 284                 else
 285                         utf_o->u_name[utf_o->u_len++] = '?';
 286         }
 287         utf_o->u_cmpID = 8;
 288
 289         return utf_o->u_len;
 290 }
 291
 292 static int udf_NLStoCS0(struct nls_table *nls, dstring *ocu, struct ustr *uni,
 293                         int length)
 294 {
 295         int len;
 296         unsigned i, max_val;
 297         uint16_t uni_char;
 298         int u_len;
 299
 300         memset(ocu, 0, sizeof(dstring) * length);
 301         ocu[0] = 8;
 302         max_val = 0xffU;
 303
 304 try_again:
 305         u_len = 0U;
 306         for (i = 0U; i < uni->u_len; i++) {
 307                 len = nls->char2uni(&uni->u_name[i], uni->u_len - i, &uni_char);
 308                 if (!len)
 309                         continue;
 310                 /* Invalid character, deal with it */
 311                 if (len < 0) {
 312                         len = 1;
 313                         uni_char = '?';
 314                 }
 315
 316                 if (uni_char > max_val) {
 317                         max_val = 0xffffU;
 318                         ocu[0] = (uint8_t)0x10U;
 319                         goto try_again;
 320                 }
 321
 322                 if (max_val == 0xffffU)
 323                         ocu[++u_len] = (uint8_t)(uni_char >> 8);
 324                 ocu[++u_len] = (uint8_t)(uni_char & 0xffU);
 325                 i += len - 1;
 326         }
 327
 328         ocu[length - 1] = (uint8_t)u_len + 1;
 329         return u_len + 1;
 330 }
 331
 332 int udf_get_filename(struct super_block *sb, uint8_t *sname, int slen,
 333                      uint8_t *dname, int dlen)
 334 {
 335         struct ustr *filename, *unifilename;
 336         int ret;
 337
 338         if (!slen)
 339                 return -EIO;
 340
 341         filename = kmalloc(sizeof(struct ustr), GFP_NOFS);
 342         if (!filename)
 343                 return -ENOMEM;
 344
 345         unifilename = kmalloc(sizeof(struct ustr), GFP_NOFS);
 346         if (!unifilename) {
 347                 ret = -ENOMEM;
 348                 goto out1;
 349         }
 350
 351         udf_build_ustr_exact(unifilename, sname, slen);
 352         if (UDF_QUERY_FLAG(sb, UDF_FLAG_UTF8)) {
 353                 ret = udf_CS0toUTF8(filename, unifilename);
 354                 if (ret < 0) {
 355                         udf_debug("Failed in udf_get_filename: sname = %s\n",
 356                                   sname);
 357                         goto out2;
 358                 }
 359         } else if (UDF_QUERY_FLAG(sb, UDF_FLAG_NLS_MAP)) {
 360                 ret = udf_CS0toNLS(UDF_SB(sb)->s_nls_map, filename,
 361                                    unifilename);
 362                 if (ret < 0) {
 363                         udf_debug("Failed in udf_get_filename: sname = %s\n",
 364                                   sname);
 365                         goto out2;
 366                 }
 367         } else
 368                 BUG();
 369
 370         ret = udf_translate_to_linux(dname, dlen,
 371                                      filename->u_name, filename->u_len,
 372                                      unifilename->u_name, unifilename->u_len);
 373         /* Zero length filename isn't valid... */
 374         if (ret == 0)
 375                 ret = -EINVAL;
 376 out2:
 377         kfree(unifilename);
 378 out1:
 379         kfree(filename);
 380         return ret;
 381 }
 382
 383 int udf_put_filename(struct super_block *sb, const uint8_t *sname,
 384                      uint8_t *dname, int flen)
 385 {
 386         struct ustr unifilename;
 387         int namelen;
 388
 389         if (!udf_char_to_ustr(&unifilename, sname, flen))
 390                 return 0;
 391
 392         if (UDF_QUERY_FLAG(sb, UDF_FLAG_UTF8)) {
 393                 namelen = udf_UTF8toCS0(dname, &unifilename, UDF_NAME_LEN);
 394                 if (!namelen)
 395                         return 0;
 396         } else if (UDF_QUERY_FLAG(sb, UDF_FLAG_NLS_MAP)) {
 397                 namelen = udf_NLStoCS0(UDF_SB(sb)->s_nls_map, dname,
 398                                         &unifilename, UDF_NAME_LEN);
 399                 if (!namelen)
 400                         return 0;
 401         } else
 402                 return 0;
 403
 404         return namelen;
 405 }
 406
 407 #define ILLEGAL_CHAR_MARK       '_'
 408 #define EXT_MARK                '.'
 409 #define CRC_MARK                '#'
 410 #define EXT_SIZE                5
 411 /* Number of chars we need to store generated CRC to make filename unique */
 412 #define CRC_LEN                 5
 413
 414 static int udf_translate_to_linux(uint8_t *newName, int newLen,
 415                                   uint8_t *udfName, int udfLen,
 416                                   uint8_t *fidName, int fidNameLen)
 417 {
 418         int index, newIndex = 0, needsCRC = 0;
 419         int extIndex = 0, newExtIndex = 0, hasExt = 0;
 420         unsigned short valueCRC;
 421         uint8_t curr;
 422
 423         if (udfName[0] == '.' &&
 424             (udfLen == 1 || (udfLen == 2 && udfName[1] == '.'))) {
 425                 needsCRC = 1;
 426                 newIndex = udfLen;
 427                 memcpy(newName, udfName, udfLen);
 428         } else {
 429                 for (index = 0; index < udfLen; index++) {
 430                         curr = udfName[index];
 431                         if (curr == '/' || curr == 0) {
 432                                 needsCRC = 1;
 433                                 curr = ILLEGAL_CHAR_MARK;
 434                                 while (index + 1 < udfLen &&
 435                                                 (udfName[index + 1] == '/' ||
 436                                                  udfName[index + 1] == 0))
 437                                         index++;
 438                         }
 439                         if (curr == EXT_MARK &&
 440                                         (udfLen - index - 1) <= EXT_SIZE) {
 441                                 if (udfLen == index + 1)
 442                                         hasExt = 0;
 443                                 else {
 444                                         hasExt = 1;
 445                                         extIndex = index;
 446                                         newExtIndex = newIndex;
 447                                 }
 448                         }
 449                         if (newIndex < newLen)
 450                                 newName[newIndex++] = curr;
 451                         else
 452                                 needsCRC = 1;
 453                 }
 454         }
 455         if (needsCRC) {
 456                 uint8_t ext[EXT_SIZE];
 457                 int localExtIndex = 0;
 458
 459                 if (hasExt) {
 460                         int maxFilenameLen;
 461                         for (index = 0;
 462                              index < EXT_SIZE && extIndex + index + 1 < udfLen;
 463                              index++) {
 464                                 curr = udfName[extIndex + index + 1];
 465
 466                                 if (curr == '/' || curr == 0) {
 467                                         needsCRC = 1;
 468                                         curr = ILLEGAL_CHAR_MARK;
 469                                         while (extIndex + index + 2 < udfLen &&
 470                                               (index + 1 < EXT_SIZE &&
 471                                                 (udfName[extIndex + index + 2] == '/' ||
 472                                                  udfName[extIndex + index + 2] == 0)))
 473                                                 index++;
 474                                 }
 475                                 ext[localExtIndex++] = curr;
 476                         }
 477                         maxFilenameLen = newLen - CRC_LEN - localExtIndex;
 478                         if (newIndex > maxFilenameLen)
 479                                 newIndex = maxFilenameLen;
 480                         else
 481                                 newIndex = newExtIndex;
 482                 } else if (newIndex > newLen - CRC_LEN)
 483                         newIndex = newLen - CRC_LEN;
 484                 newName[newIndex++] = CRC_MARK;
 485                 valueCRC = crc_itu_t(0, fidName, fidNameLen);
 486                 newName[newIndex++] = hex_asc_upper_hi(valueCRC >> 8);
 487                 newName[newIndex++] = hex_asc_upper_lo(valueCRC >> 8);
 488                 newName[newIndex++] = hex_asc_upper_hi(valueCRC);
 489                 newName[newIndex++] = hex_asc_upper_lo(valueCRC);
 490
 491                 if (hasExt) {
 492                         newName[newIndex++] = EXT_MARK;
 493                         for (index = 0; index < localExtIndex; index++)
 494                                 newName[newIndex++] = ext[index];
 495                 }
 496         }
 497
 498         return newIndex;
 499 }