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 static int udf_uni2char_utf8(wchar_t uni,
  80                              unsigned char *out,
  81                              int boundlen)
  82 {
  83         int u_len = 0;
  84
  85         if (boundlen <= 0)
  86                 return -ENAMETOOLONG;
  87
  88         if (uni < 0x80) {
  89                 out[u_len++] = (unsigned char)uni;
  90         } else if (uni < 0x800) {
  91                 if (boundlen < 2)
  92                         return -ENAMETOOLONG;
  93                 out[u_len++] = (unsigned char)(0xc0 | (uni >> 6));
  94                 out[u_len++] = (unsigned char)(0x80 | (uni & 0x3f));
  95         } else {
  96                 if (boundlen < 3)
  97                         return -ENAMETOOLONG;
  98                 out[u_len++] = (unsigned char)(0xe0 | (uni >> 12));
  99                 out[u_len++] = (unsigned char)(0x80 | ((uni >> 6) & 0x3f));
 100                 out[u_len++] = (unsigned char)(0x80 | (uni & 0x3f));
 101         }
 102         return u_len;
 103 }
 104
 105 static int udf_char2uni_utf8(const unsigned char *in,
 106                              int boundlen,
 107                              wchar_t *uni)
 108 {
 109         unsigned int utf_char;
 110         unsigned char c;
 111         int utf_cnt, u_len;
 112
 113         utf_char = 0;
 114         utf_cnt = 0;
 115         for (u_len = 0; u_len < boundlen;) {
 116                 c = in[u_len++];
 117
 118                 /* Complete a multi-byte UTF-8 character */
 119                 if (utf_cnt) {
 120                         utf_char = (utf_char << 6) | (c & 0x3f);
 121                         if (--utf_cnt)
 122                                 continue;
 123                 } else {
 124                         /* Check for a multi-byte UTF-8 character */
 125                         if (c & 0x80) {
 126                                 /* Start a multi-byte UTF-8 character */
 127                                 if ((c & 0xe0) == 0xc0) {
 128                                         utf_char = c & 0x1f;
 129                                         utf_cnt = 1;
 130                                 } else if ((c & 0xf0) == 0xe0) {
 131                                         utf_char = c & 0x0f;
 132                                         utf_cnt = 2;
 133                                 } else if ((c & 0xf8) == 0xf0) {
 134                                         utf_char = c & 0x07;
 135                                         utf_cnt = 3;
 136                                 } else if ((c & 0xfc) == 0xf8) {
 137                                         utf_char = c & 0x03;
 138                                         utf_cnt = 4;
 139                                 } else if ((c & 0xfe) == 0xfc) {
 140                                         utf_char = c & 0x01;
 141                                         utf_cnt = 5;
 142                                 } else {
 143                                         utf_cnt = -1;
 144                                         break;
 145                                 }
 146                                 continue;
 147                         } else {
 148                                 /* Single byte UTF-8 character (most common) */
 149                                 utf_char = c;
 150                         }
 151                 }
 152                 *uni = utf_char;
 153                 break;
 154         }
 155         if (utf_cnt) {
 156                 *uni = '?';
 157                 return -EINVAL;
 158         }
 159         return u_len;
 160 }
 161
 162 static int udf_name_from_CS0(struct ustr *utf_o,
 163                              const struct ustr *ocu_i,
 164                              int (*conv_f)(wchar_t, unsigned char *, int))
 165 {
 166         const uint8_t *ocu;
 167         uint8_t cmp_id, ocu_len;
 168         int i, len;
 169
 170
 171         ocu_len = ocu_i->u_len;
 172         if (ocu_len == 0) {
 173                 memset(utf_o, 0, sizeof(struct ustr));
 174                 return 0;
 175         }
 176
 177         cmp_id = ocu_i->u_cmpID;
 178         if (cmp_id != 8 && cmp_id != 16) {
 179                 memset(utf_o, 0, sizeof(struct ustr));
 180                 pr_err("unknown compression code (%d) stri=%s\n",
 181                        cmp_id, ocu_i->u_name);
 182                 return -EINVAL;
 183         }
 184
 185         ocu = ocu_i->u_name;
 186         utf_o->u_len = 0;
 187         for (i = 0; (i < ocu_len) && (utf_o->u_len <= (UDF_NAME_LEN - 3));) {
 188                 /* Expand OSTA compressed Unicode to Unicode */
 189                 uint32_t c = ocu[i++];
 190                 if (cmp_id == 16)
 191                         c = (c << 8) | ocu[i++];
 192
 193                 len = conv_f(c, &utf_o->u_name[utf_o->u_len],
 194                              UDF_NAME_LEN - 2 - utf_o->u_len);
 195                 /* Valid character? */
 196                 if (len >= 0)
 197                         utf_o->u_len += len;
 198                 else if (len == -ENAMETOOLONG)
 199                         break;
 200                 else
 201                         utf_o->u_name[utf_o->u_len++] = '?';
 202         }
 203         utf_o->u_cmpID = 8;
 204
 205         return utf_o->u_len;
 206 }
 207
 208 static int udf_name_to_CS0(dstring *ocu, struct ustr *uni, int length,
 209                            int (*conv_f)(const unsigned char *, int, wchar_t *))
 210 {
 211         int i, len;
 212         unsigned int max_val;
 213         wchar_t uni_char;
 214         int u_len, u_ch;
 215
 216         memset(ocu, 0, sizeof(dstring) * length);
 217         ocu[0] = 8;
 218         max_val = 0xff;
 219         u_ch = 1;
 220
 221 try_again:
 222         u_len = 0;
 223         for (i = 0; i < uni->u_len; i++) {
 224                 /* Name didn't fit? */
 225                 if (u_len + 1 + u_ch >= length)
 226                         return 0;
 227                 len = conv_f(&uni->u_name[i], uni->u_len - i, &uni_char);
 228                 if (!len)
 229                         continue;
 230                 /* Invalid character, deal with it */
 231                 if (len < 0) {
 232                         len = 1;
 233                         uni_char = '?';
 234                 }
 235
 236                 if (uni_char > max_val) {
 237                         max_val = 0xffff;
 238                         ocu[0] = 0x10;
 239                         u_ch = 2;
 240                         goto try_again;
 241                 }
 242
 243                 if (max_val == 0xffff)
 244                         ocu[++u_len] = (uint8_t)(uni_char >> 8);
 245                 ocu[++u_len] = (uint8_t)(uni_char & 0xff);
 246                 i += len - 1;
 247         }
 248
 249         ocu[length - 1] = (uint8_t)u_len + 1;
 250         return u_len + 1;
 251 }
 252
 253 int udf_CS0toUTF8(struct ustr *utf_o, const struct ustr *ocu_i)
 254 {
 255         return udf_name_from_CS0(utf_o, ocu_i, udf_uni2char_utf8);
 256 }
 257
 258 int udf_get_filename(struct super_block *sb, uint8_t *sname, int slen,
 259                      uint8_t *dname, int dlen)
 260 {
 261         struct ustr *filename, *unifilename;
 262         int (*conv_f)(wchar_t, unsigned char *, int);
 263         int ret;
 264
 265         if (!slen)
 266                 return -EIO;
 267
 268         filename = kmalloc(sizeof(struct ustr), GFP_NOFS);
 269         if (!filename)
 270                 return -ENOMEM;
 271
 272         unifilename = kmalloc(sizeof(struct ustr), GFP_NOFS);
 273         if (!unifilename) {
 274                 ret = -ENOMEM;
 275                 goto out1;
 276         }
 277
 278         udf_build_ustr_exact(unifilename, sname, slen);
 279         if (UDF_QUERY_FLAG(sb, UDF_FLAG_UTF8)) {
 280                 conv_f = udf_uni2char_utf8;
 281         } else if (UDF_QUERY_FLAG(sb, UDF_FLAG_NLS_MAP)) {
 282                 conv_f = UDF_SB(sb)->s_nls_map->uni2char;
 283         } else
 284                 BUG();
 285
 286         ret = udf_name_from_CS0(filename, unifilename, conv_f);
 287         if (ret < 0) {
 288                 udf_debug("Failed in udf_get_filename: sname = %s\n", sname);
 289                 goto out2;
 290         }
 291
 292         ret = udf_translate_to_linux(dname, dlen,
 293                                      filename->u_name, filename->u_len,
 294                                      unifilename->u_name, unifilename->u_len);
 295         /* Zero length filename isn't valid... */
 296         if (ret == 0)
 297                 ret = -EINVAL;
 298 out2:
 299         kfree(unifilename);
 300 out1:
 301         kfree(filename);
 302         return ret;
 303 }
 304
 305 int udf_put_filename(struct super_block *sb, const uint8_t *sname, int slen,
 306                      uint8_t *dname, int dlen)
 307 {
 308         struct ustr unifilename;
 309         int (*conv_f)(const unsigned char *, int, wchar_t *);
 310
 311         if (!udf_char_to_ustr(&unifilename, sname, slen))
 312                 return 0;
 313
 314         if (UDF_QUERY_FLAG(sb, UDF_FLAG_UTF8)) {
 315                 conv_f = udf_char2uni_utf8;
 316         } else if (UDF_QUERY_FLAG(sb, UDF_FLAG_NLS_MAP)) {
 317                 conv_f = UDF_SB(sb)->s_nls_map->char2uni;
 318         } else
 319                 BUG();
 320
 321         return udf_name_to_CS0(dname, &unifilename, dlen, conv_f);
 322 }
 323
 324 #define ILLEGAL_CHAR_MARK       '_'
 325 #define EXT_MARK                '.'
 326 #define CRC_MARK                '#'
 327 #define EXT_SIZE                5
 328 /* Number of chars we need to store generated CRC to make filename unique */
 329 #define CRC_LEN                 5
 330
 331 static int udf_translate_to_linux(uint8_t *newName, int newLen,
 332                                   uint8_t *udfName, int udfLen,
 333                                   uint8_t *fidName, int fidNameLen)
 334 {
 335         int index, newIndex = 0, needsCRC = 0;
 336         int extIndex = 0, newExtIndex = 0, hasExt = 0;
 337         unsigned short valueCRC;
 338         uint8_t curr;
 339
 340         if (udfName[0] == '.' &&
 341             (udfLen == 1 || (udfLen == 2 && udfName[1] == '.'))) {
 342                 needsCRC = 1;
 343                 newIndex = udfLen;
 344                 memcpy(newName, udfName, udfLen);
 345         } else {
 346                 for (index = 0; index < udfLen; index++) {
 347                         curr = udfName[index];
 348                         if (curr == '/' || curr == 0) {
 349                                 needsCRC = 1;
 350                                 curr = ILLEGAL_CHAR_MARK;
 351                                 while (index + 1 < udfLen &&
 352                                                 (udfName[index + 1] == '/' ||
 353                                                  udfName[index + 1] == 0))
 354                                         index++;
 355                         }
 356                         if (curr == EXT_MARK &&
 357                                         (udfLen - index - 1) <= EXT_SIZE) {
 358                                 if (udfLen == index + 1)
 359                                         hasExt = 0;
 360                                 else {
 361                                         hasExt = 1;
 362                                         extIndex = index;
 363                                         newExtIndex = newIndex;
 364                                 }
 365                         }
 366                         if (newIndex < newLen)
 367                                 newName[newIndex++] = curr;
 368                         else
 369                                 needsCRC = 1;
 370                 }
 371         }
 372         if (needsCRC) {
 373                 uint8_t ext[EXT_SIZE];
 374                 int localExtIndex = 0;
 375
 376                 if (hasExt) {
 377                         int maxFilenameLen;
 378                         for (index = 0;
 379                              index < EXT_SIZE && extIndex + index + 1 < udfLen;
 380                              index++) {
 381                                 curr = udfName[extIndex + index + 1];
 382
 383                                 if (curr == '/' || curr == 0) {
 384                                         needsCRC = 1;
 385                                         curr = ILLEGAL_CHAR_MARK;
 386                                         while (extIndex + index + 2 < udfLen &&
 387                                               (index + 1 < EXT_SIZE &&
 388                                                 (udfName[extIndex + index + 2] == '/' ||
 389                                                  udfName[extIndex + index + 2] == 0)))
 390                                                 index++;
 391                                 }
 392                                 ext[localExtIndex++] = curr;
 393                         }
 394                         maxFilenameLen = newLen - CRC_LEN - localExtIndex;
 395                         if (newIndex > maxFilenameLen)
 396                                 newIndex = maxFilenameLen;
 397                         else
 398                                 newIndex = newExtIndex;
 399                 } else if (newIndex > newLen - CRC_LEN)
 400                         newIndex = newLen - CRC_LEN;
 401                 newName[newIndex++] = CRC_MARK;
 402                 valueCRC = crc_itu_t(0, fidName, fidNameLen);
 403                 newName[newIndex++] = hex_asc_upper_hi(valueCRC >> 8);
 404                 newName[newIndex++] = hex_asc_upper_lo(valueCRC >> 8);
 405                 newName[newIndex++] = hex_asc_upper_hi(valueCRC);
 406                 newName[newIndex++] = hex_asc_upper_lo(valueCRC);
 407
 408                 if (hasExt) {
 409                         newName[newIndex++] = EXT_MARK;
 410                         for (index = 0; index < localExtIndex; index++)
 411                                 newName[newIndex++] = ext[index];
 412                 }
 413         }
 414
 415         return newIndex;
 416 }