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                         if (utf_o->u_len > (UDF_NAME_LEN - 4))
 132                                 break;
 133                         utf_o->u_name[utf_o->u_len++] =
 134                                                 (uint8_t)(0xc0 | (c >> 6));
 135                         utf_o->u_name[utf_o->u_len++] =
 136                                                 (uint8_t)(0x80 | (c & 0x3f));
 137                 } else {
 138                         if (utf_o->u_len > (UDF_NAME_LEN - 5))
 139                                 break;
 140                         utf_o->u_name[utf_o->u_len++] =
 141                                                 (uint8_t)(0xe0 | (c >> 12));
 142                         utf_o->u_name[utf_o->u_len++] =
 143                                                 (uint8_t)(0x80 |
 144                                                           ((c >> 6) & 0x3f));
 145                         utf_o->u_name[utf_o->u_len++] =
 146                                                 (uint8_t)(0x80 | (c & 0x3f));
 147                 }
 148         }
 149         utf_o->u_cmpID = 8;
 150
 151         return utf_o->u_len;
 152 }
 153
 154 /*
 155  *
 156  * udf_UTF8toCS0
 157  *
 158  * PURPOSE
 159  *      Convert UTF-8 to the OSTA Compressed Unicode equivalent.
 160  *
 161  * DESCRIPTION
 162  *      This routine is only called by udf_lookup().
 163  *
 164  * PRE-CONDITIONS
 165  *      ocu                     Pointer to OSTA Compressed Unicode output
 166  *                              buffer of size UDF_NAME_LEN bytes.
 167  *      utf                     Pointer to UTF-8 input buffer.
 168  *      utf_len                 Length of UTF-8 input buffer in bytes.
 169  *
 170  * POST-CONDITIONS
 171  *      <return>                Zero on success.
 172  *
 173  * HISTORY
 174  *      November 12, 1997 - Andrew E. Mileski
 175  *      Written, tested, and released.
 176  */
 177 static int udf_UTF8toCS0(dstring *ocu, struct ustr *utf, int length)
 178 {
 179         unsigned c, i, max_val, utf_char;
 180         int utf_cnt, u_len;
 181
 182         memset(ocu, 0, sizeof(dstring) * length);
 183         ocu[0] = 8;
 184         max_val = 0xffU;
 185
 186 try_again:
 187         u_len = 0U;
 188         utf_char = 0U;
 189         utf_cnt = 0U;
 190         for (i = 0U; i < utf->u_len; i++) {
 191                 c = (uint8_t)utf->u_name[i];
 192
 193                 /* Complete a multi-byte UTF-8 character */
 194                 if (utf_cnt) {
 195                         utf_char = (utf_char << 6) | (c & 0x3fU);
 196                         if (--utf_cnt)
 197                                 continue;
 198                 } else {
 199                         /* Check for a multi-byte UTF-8 character */
 200                         if (c & 0x80U) {
 201                                 /* Start a multi-byte UTF-8 character */
 202                                 if ((c & 0xe0U) == 0xc0U) {
 203                                         utf_char = c & 0x1fU;
 204                                         utf_cnt = 1;
 205                                 } else if ((c & 0xf0U) == 0xe0U) {
 206                                         utf_char = c & 0x0fU;
 207                                         utf_cnt = 2;
 208                                 } else if ((c & 0xf8U) == 0xf0U) {
 209                                         utf_char = c & 0x07U;
 210                                         utf_cnt = 3;
 211                                 } else if ((c & 0xfcU) == 0xf8U) {
 212                                         utf_char = c & 0x03U;
 213                                         utf_cnt = 4;
 214                                 } else if ((c & 0xfeU) == 0xfcU) {
 215                                         utf_char = c & 0x01U;
 216                                         utf_cnt = 5;
 217                                 } else {
 218                                         goto error_out;
 219                                 }
 220                                 continue;
 221                         } else {
 222                                 /* Single byte UTF-8 character (most common) */
 223                                 utf_char = c;
 224                         }
 225                 }
 226
 227                 /* Choose no compression if necessary */
 228                 if (utf_char > max_val) {
 229                         if (max_val == 0xffU) {
 230                                 max_val = 0xffffU;
 231                                 ocu[0] = (uint8_t)0x10U;
 232                                 goto try_again;
 233                         }
 234                         goto error_out;
 235                 }
 236
 237                 if (max_val == 0xffffU)
 238                         ocu[++u_len] = (uint8_t)(utf_char >> 8);
 239                 ocu[++u_len] = (uint8_t)(utf_char & 0xffU);
 240         }
 241
 242         if (utf_cnt) {
 243 error_out:
 244                 ocu[++u_len] = '?';
 245                 printk(KERN_DEBUG pr_fmt("bad UTF-8 character\n"));
 246         }
 247
 248         ocu[length - 1] = (uint8_t)u_len + 1;
 249
 250         return u_len + 1;
 251 }
 252
 253 static int udf_CS0toNLS(struct nls_table *nls, struct ustr *utf_o,
 254                         const struct ustr *ocu_i)
 255 {
 256         const uint8_t *ocu;
 257         uint8_t cmp_id, ocu_len;
 258         int i, len;
 259
 260
 261         ocu_len = ocu_i->u_len;
 262         if (ocu_len == 0) {
 263                 memset(utf_o, 0, sizeof(struct ustr));
 264                 return 0;
 265         }
 266
 267         cmp_id = ocu_i->u_cmpID;
 268         if (cmp_id != 8 && cmp_id != 16) {
 269                 memset(utf_o, 0, sizeof(struct ustr));
 270                 pr_err("unknown compression code (%d) stri=%s\n",
 271                        cmp_id, ocu_i->u_name);
 272                 return -EINVAL;
 273         }
 274
 275         ocu = ocu_i->u_name;
 276         utf_o->u_len = 0;
 277         for (i = 0; (i < ocu_len) && (utf_o->u_len <= (UDF_NAME_LEN - 3));) {
 278                 /* Expand OSTA compressed Unicode to Unicode */
 279                 uint32_t c = ocu[i++];
 280                 if (cmp_id == 16)
 281                         c = (c << 8) | ocu[i++];
 282
 283                 len = nls->uni2char(c, &utf_o->u_name[utf_o->u_len],
 284                                     UDF_NAME_LEN - 2 - utf_o->u_len);
 285                 /* Valid character? */
 286                 if (len >= 0)
 287                         utf_o->u_len += len;
 288                 else
 289                         utf_o->u_name[utf_o->u_len++] = '?';
 290         }
 291         utf_o->u_cmpID = 8;
 292
 293         return utf_o->u_len;
 294 }
 295
 296 static int udf_NLStoCS0(struct nls_table *nls, dstring *ocu, struct ustr *uni,
 297                         int length)
 298 {
 299         int len;
 300         unsigned i, max_val;
 301         uint16_t uni_char;
 302         int u_len;
 303
 304         memset(ocu, 0, sizeof(dstring) * length);
 305         ocu[0] = 8;
 306         max_val = 0xffU;
 307
 308 try_again:
 309         u_len = 0U;
 310         for (i = 0U; i < uni->u_len; i++) {
 311                 len = nls->char2uni(&uni->u_name[i], uni->u_len - i, &uni_char);
 312                 if (!len)
 313                         continue;
 314                 /* Invalid character, deal with it */
 315                 if (len < 0) {
 316                         len = 1;
 317                         uni_char = '?';
 318                 }
 319
 320                 if (uni_char > max_val) {
 321                         max_val = 0xffffU;
 322                         ocu[0] = (uint8_t)0x10U;
 323                         goto try_again;
 324                 }
 325
 326                 if (max_val == 0xffffU)
 327                         ocu[++u_len] = (uint8_t)(uni_char >> 8);
 328                 ocu[++u_len] = (uint8_t)(uni_char & 0xffU);
 329                 i += len - 1;
 330         }
 331
 332         ocu[length - 1] = (uint8_t)u_len + 1;
 333         return u_len + 1;
 334 }
 335
 336 int udf_get_filename(struct super_block *sb, uint8_t *sname, int slen,
 337                      uint8_t *dname, int dlen)
 338 {
 339         struct ustr *filename, *unifilename;
 340         int ret;
 341
 342         if (!slen)
 343                 return -EIO;
 344
 345         filename = kmalloc(sizeof(struct ustr), GFP_NOFS);
 346         if (!filename)
 347                 return -ENOMEM;
 348
 349         unifilename = kmalloc(sizeof(struct ustr), GFP_NOFS);
 350         if (!unifilename) {
 351                 ret = -ENOMEM;
 352                 goto out1;
 353         }
 354
 355         udf_build_ustr_exact(unifilename, sname, slen);
 356         if (UDF_QUERY_FLAG(sb, UDF_FLAG_UTF8)) {
 357                 ret = udf_CS0toUTF8(filename, unifilename);
 358                 if (ret < 0) {
 359                         udf_debug("Failed in udf_get_filename: sname = %s\n",
 360                                   sname);
 361                         goto out2;
 362                 }
 363         } else if (UDF_QUERY_FLAG(sb, UDF_FLAG_NLS_MAP)) {
 364                 ret = udf_CS0toNLS(UDF_SB(sb)->s_nls_map, filename,
 365                                    unifilename);
 366                 if (ret < 0) {
 367                         udf_debug("Failed in udf_get_filename: sname = %s\n",
 368                                   sname);
 369                         goto out2;
 370                 }
 371         } else
 372                 BUG();
 373
 374         ret = udf_translate_to_linux(dname, dlen,
 375                                      filename->u_name, filename->u_len,
 376                                      unifilename->u_name, unifilename->u_len);
 377         /* Zero length filename isn't valid... */
 378         if (ret == 0)
 379                 ret = -EINVAL;
 380 out2:
 381         kfree(unifilename);
 382 out1:
 383         kfree(filename);
 384         return ret;
 385 }
 386
 387 int udf_put_filename(struct super_block *sb, const uint8_t *sname,
 388                      uint8_t *dname, int flen)
 389 {
 390         struct ustr unifilename;
 391         int namelen;
 392
 393         if (!udf_char_to_ustr(&unifilename, sname, flen))
 394                 return 0;
 395
 396         if (UDF_QUERY_FLAG(sb, UDF_FLAG_UTF8)) {
 397                 namelen = udf_UTF8toCS0(dname, &unifilename, UDF_NAME_LEN);
 398                 if (!namelen)
 399                         return 0;
 400         } else if (UDF_QUERY_FLAG(sb, UDF_FLAG_NLS_MAP)) {
 401                 namelen = udf_NLStoCS0(UDF_SB(sb)->s_nls_map, dname,
 402                                         &unifilename, UDF_NAME_LEN);
 403                 if (!namelen)
 404                         return 0;
 405         } else
 406                 return 0;
 407
 408         return namelen;
 409 }
 410
 411 #define ILLEGAL_CHAR_MARK       '_'
 412 #define EXT_MARK                '.'
 413 #define CRC_MARK                '#'
 414 #define EXT_SIZE                5
 415 /* Number of chars we need to store generated CRC to make filename unique */
 416 #define CRC_LEN                 5
 417
 418 static int udf_translate_to_linux(uint8_t *newName, int newLen,
 419                                   uint8_t *udfName, int udfLen,
 420                                   uint8_t *fidName, int fidNameLen)
 421 {
 422         int index, newIndex = 0, needsCRC = 0;
 423         int extIndex = 0, newExtIndex = 0, hasExt = 0;
 424         unsigned short valueCRC;
 425         uint8_t curr;
 426
 427         if (udfName[0] == '.' &&
 428             (udfLen == 1 || (udfLen == 2 && udfName[1] == '.'))) {
 429                 needsCRC = 1;
 430                 newIndex = udfLen;
 431                 memcpy(newName, udfName, udfLen);
 432         } else {
 433                 for (index = 0; index < udfLen; index++) {
 434                         curr = udfName[index];
 435                         if (curr == '/' || curr == 0) {
 436                                 needsCRC = 1;
 437                                 curr = ILLEGAL_CHAR_MARK;
 438                                 while (index + 1 < udfLen &&
 439                                                 (udfName[index + 1] == '/' ||
 440                                                  udfName[index + 1] == 0))
 441                                         index++;
 442                         }
 443                         if (curr == EXT_MARK &&
 444                                         (udfLen - index - 1) <= EXT_SIZE) {
 445                                 if (udfLen == index + 1)
 446                                         hasExt = 0;
 447                                 else {
 448                                         hasExt = 1;
 449                                         extIndex = index;
 450                                         newExtIndex = newIndex;
 451                                 }
 452                         }
 453                         if (newIndex < newLen)
 454                                 newName[newIndex++] = curr;
 455                         else
 456                                 needsCRC = 1;
 457                 }
 458         }
 459         if (needsCRC) {
 460                 uint8_t ext[EXT_SIZE];
 461                 int localExtIndex = 0;
 462
 463                 if (hasExt) {
 464                         int maxFilenameLen;
 465                         for (index = 0;
 466                              index < EXT_SIZE && extIndex + index + 1 < udfLen;
 467                              index++) {
 468                                 curr = udfName[extIndex + index + 1];
 469
 470                                 if (curr == '/' || curr == 0) {
 471                                         needsCRC = 1;
 472                                         curr = ILLEGAL_CHAR_MARK;
 473                                         while (extIndex + index + 2 < udfLen &&
 474                                               (index + 1 < EXT_SIZE &&
 475                                                 (udfName[extIndex + index + 2] == '/' ||
 476                                                  udfName[extIndex + index + 2] == 0)))
 477                                                 index++;
 478                                 }
 479                                 ext[localExtIndex++] = curr;
 480                         }
 481                         maxFilenameLen = newLen - CRC_LEN - localExtIndex;
 482                         if (newIndex > maxFilenameLen)
 483                                 newIndex = maxFilenameLen;
 484                         else
 485                                 newIndex = newExtIndex;
 486                 } else if (newIndex > newLen - CRC_LEN)
 487                         newIndex = newLen - CRC_LEN;
 488                 newName[newIndex++] = CRC_MARK;
 489                 valueCRC = crc_itu_t(0, fidName, fidNameLen);
 490                 newName[newIndex++] = hex_asc_upper_hi(valueCRC >> 8);
 491                 newName[newIndex++] = hex_asc_upper_lo(valueCRC >> 8);
 492                 newName[newIndex++] = hex_asc_upper_hi(valueCRC);
 493                 newName[newIndex++] = hex_asc_upper_lo(valueCRC);
 494
 495                 if (hasExt) {
 496                         newName[newIndex++] = EXT_MARK;
 497                         for (index = 0; index < localExtIndex; index++)
 498                                 newName[newIndex++] = ext[index];
 499                 }
 500         }
 501
 502         return newIndex;
 503 }