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_uni2char_utf8(wchar_t uni,
  32                              unsigned char *out,
  33                              int boundlen)
  34 {
  35         int u_len = 0;
  36
  37         if (boundlen <= 0)
  38                 return -ENAMETOOLONG;
  39
  40         if (uni < 0x80) {
  41                 out[u_len++] = (unsigned char)uni;
  42         } else if (uni < 0x800) {
  43                 if (boundlen < 2)
  44                         return -ENAMETOOLONG;
  45                 out[u_len++] = (unsigned char)(0xc0 | (uni >> 6));
  46                 out[u_len++] = (unsigned char)(0x80 | (uni & 0x3f));
  47         } else {
  48                 if (boundlen < 3)
  49                         return -ENAMETOOLONG;
  50                 out[u_len++] = (unsigned char)(0xe0 | (uni >> 12));
  51                 out[u_len++] = (unsigned char)(0x80 | ((uni >> 6) & 0x3f));
  52                 out[u_len++] = (unsigned char)(0x80 | (uni & 0x3f));
  53         }
  54         return u_len;
  55 }
  56
  57 static int udf_char2uni_utf8(const unsigned char *in,
  58                              int boundlen,
  59                              wchar_t *uni)
  60 {
  61         unsigned int utf_char;
  62         unsigned char c;
  63         int utf_cnt, u_len;
  64
  65         utf_char = 0;
  66         utf_cnt = 0;
  67         for (u_len = 0; u_len < boundlen;) {
  68                 c = in[u_len++];
  69
  70                 /* Complete a multi-byte UTF-8 character */
  71                 if (utf_cnt) {
  72                         utf_char = (utf_char << 6) | (c & 0x3f);
  73                         if (--utf_cnt)
  74                                 continue;
  75                 } else {
  76                         /* Check for a multi-byte UTF-8 character */
  77                         if (c & 0x80) {
  78                                 /* Start a multi-byte UTF-8 character */
  79                                 if ((c & 0xe0) == 0xc0) {
  80                                         utf_char = c & 0x1f;
  81                                         utf_cnt = 1;
  82                                 } else if ((c & 0xf0) == 0xe0) {
  83                                         utf_char = c & 0x0f;
  84                                         utf_cnt = 2;
  85                                 } else if ((c & 0xf8) == 0xf0) {
  86                                         utf_char = c & 0x07;
  87                                         utf_cnt = 3;
  88                                 } else if ((c & 0xfc) == 0xf8) {
  89                                         utf_char = c & 0x03;
  90                                         utf_cnt = 4;
  91                                 } else if ((c & 0xfe) == 0xfc) {
  92                                         utf_char = c & 0x01;
  93                                         utf_cnt = 5;
  94                                 } else {
  95                                         utf_cnt = -1;
  96                                         break;
  97                                 }
  98                                 continue;
  99                         } else {
 100                                 /* Single byte UTF-8 character (most common) */
 101                                 utf_char = c;
 102                         }
 103                 }
 104                 *uni = utf_char;
 105                 break;
 106         }
 107         if (utf_cnt) {
 108                 *uni = '?';
 109                 return -EINVAL;
 110         }
 111         return u_len;
 112 }
 113
 114 #define ILLEGAL_CHAR_MARK       '_'
 115 #define EXT_MARK                '.'
 116 #define CRC_MARK                '#'
 117 #define EXT_SIZE                5
 118 /* Number of chars we need to store generated CRC to make filename unique */
 119 #define CRC_LEN                 5
 120
 121 static int udf_name_conv_char(uint8_t *str_o, int str_o_max_len,
 122                               int *str_o_idx,
 123                               const uint8_t *str_i, int str_i_max_len,
 124                               int *str_i_idx,
 125                               int u_ch, int *needsCRC,
 126                               int (*conv_f)(wchar_t, unsigned char *, int),
 127                               int translate)
 128 {
 129         uint32_t c;
 130         int illChar = 0;
 131         int len, gotch = 0;
 132
 133         for (; (!gotch) && (*str_i_idx < str_i_max_len); *str_i_idx += u_ch) {
 134                 if (*str_o_idx >= str_o_max_len) {
 135                         *needsCRC = 1;
 136                         return gotch;
 137                 }
 138
 139                 /* Expand OSTA compressed Unicode to Unicode */
 140                 c = str_i[*str_i_idx];
 141                 if (u_ch > 1)
 142                         c = (c << 8) | str_i[*str_i_idx + 1];
 143
 144                 if (translate && (c == '/' || c == 0))
 145                         illChar = 1;
 146                 else if (illChar)
 147                         break;
 148                 else
 149                         gotch = 1;
 150         }
 151         if (illChar) {
 152                 *needsCRC = 1;
 153                 c = ILLEGAL_CHAR_MARK;
 154                 gotch = 1;
 155         }
 156         if (gotch) {
 157                 len = conv_f(c, &str_o[*str_o_idx], str_o_max_len - *str_o_idx);
 158                 /* Valid character? */
 159                 if (len >= 0)
 160                         *str_o_idx += len;
 161                 else if (len == -ENAMETOOLONG) {
 162                         *needsCRC = 1;
 163                         gotch = 0;
 164                 } else {
 165                         str_o[(*str_o_idx)++] = '?';
 166                         *needsCRC = 1;
 167                 }
 168         }
 169         return gotch;
 170 }
 171
 172 static int udf_name_from_CS0(uint8_t *str_o, int str_max_len,
 173                              const uint8_t *ocu, int ocu_len,
 174                              int (*conv_f)(wchar_t, unsigned char *, int),
 175                              int translate)
 176 {
 177         uint32_t c;
 178         uint8_t cmp_id;
 179         int idx, len;
 180         int u_ch;
 181         int needsCRC = 0;
 182         int ext_i_len, ext_max_len;
 183         int str_o_len = 0;      /* Length of resulting output */
 184         int ext_o_len = 0;      /* Extension output length */
 185         int ext_crc_len = 0;    /* Extension output length if used with CRC */
 186         int i_ext = -1;         /* Extension position in input buffer */
 187         int o_crc = 0;          /* Rightmost possible output pos for CRC+ext */
 188         unsigned short valueCRC;
 189         uint8_t ext[EXT_SIZE * NLS_MAX_CHARSET_SIZE + 1];
 190         uint8_t crc[CRC_LEN];
 191
 192         if (str_max_len <= 0)
 193                 return 0;
 194
 195         if (ocu_len == 0) {
 196                 memset(str_o, 0, str_max_len);
 197                 return 0;
 198         }
 199
 200         cmp_id = ocu[0];
 201         if (cmp_id != 8 && cmp_id != 16) {
 202                 memset(str_o, 0, str_max_len);
 203                 pr_err("unknown compression code (%u)\n", cmp_id);
 204                 return -EINVAL;
 205         }
 206         u_ch = cmp_id >> 3;
 207
 208         ocu++;
 209         ocu_len--;
 210
 211         if (ocu_len % u_ch) {
 212                 pr_err("incorrect filename length (%d)\n", ocu_len + 1);
 213                 return -EINVAL;
 214         }
 215
 216         if (translate) {
 217                 /* Look for extension */
 218                 for (idx = ocu_len - u_ch, ext_i_len = 0;
 219                      (idx >= 0) && (ext_i_len < EXT_SIZE);
 220                      idx -= u_ch, ext_i_len++) {
 221                         c = ocu[idx];
 222                         if (u_ch > 1)
 223                                 c = (c << 8) | ocu[idx + 1];
 224
 225                         if (c == EXT_MARK) {
 226                                 if (ext_i_len)
 227                                         i_ext = idx;
 228                                 break;
 229                         }
 230                 }
 231                 if (i_ext >= 0) {
 232                         /* Convert extension */
 233                         ext_max_len = min_t(int, sizeof(ext), str_max_len);
 234                         ext[ext_o_len++] = EXT_MARK;
 235                         idx = i_ext + u_ch;
 236                         while (udf_name_conv_char(ext, ext_max_len, &ext_o_len,
 237                                                   ocu, ocu_len, &idx,
 238                                                   u_ch, &needsCRC,
 239                                                   conv_f, translate)) {
 240                                 if ((ext_o_len + CRC_LEN) < str_max_len)
 241                                         ext_crc_len = ext_o_len;
 242                         }
 243                 }
 244         }
 245
 246         idx = 0;
 247         while (1) {
 248                 if (translate && (idx == i_ext)) {
 249                         if (str_o_len > (str_max_len - ext_o_len))
 250                                 needsCRC = 1;
 251                         break;
 252                 }
 253
 254                 if (!udf_name_conv_char(str_o, str_max_len, &str_o_len,
 255                                         ocu, ocu_len, &idx,
 256                                         u_ch, &needsCRC, conv_f, translate))
 257                         break;
 258
 259                 if (translate &&
 260                     (str_o_len <= (str_max_len - ext_o_len - CRC_LEN)))
 261                         o_crc = str_o_len;
 262         }
 263
 264         if (translate) {
 265                 if (str_o_len <= 2 && str_o[0] == '.' &&
 266                     (str_o_len == 1 || str_o[1] == '.'))
 267                         needsCRC = 1;
 268                 if (needsCRC) {
 269                         str_o_len = o_crc;
 270                         valueCRC = crc_itu_t(0, ocu, ocu_len);
 271                         crc[0] = CRC_MARK;
 272                         crc[1] = hex_asc_upper_hi(valueCRC >> 8);
 273                         crc[2] = hex_asc_upper_lo(valueCRC >> 8);
 274                         crc[3] = hex_asc_upper_hi(valueCRC);
 275                         crc[4] = hex_asc_upper_lo(valueCRC);
 276                         len = min_t(int, CRC_LEN, str_max_len - str_o_len);
 277                         memcpy(&str_o[str_o_len], crc, len);
 278                         str_o_len += len;
 279                         ext_o_len = ext_crc_len;
 280                 }
 281                 if (ext_o_len > 0) {
 282                         memcpy(&str_o[str_o_len], ext, ext_o_len);
 283                         str_o_len += ext_o_len;
 284                 }
 285         }
 286
 287         return str_o_len;
 288 }
 289
 290 static int udf_name_to_CS0(uint8_t *ocu, int ocu_max_len,
 291                            const uint8_t *str_i, int str_len,
 292                            int (*conv_f)(const unsigned char *, int, wchar_t *))
 293 {
 294         int i, len;
 295         unsigned int max_val;
 296         wchar_t uni_char;
 297         int u_len, u_ch;
 298
 299         if (ocu_max_len <= 0)
 300                 return 0;
 301
 302         memset(ocu, 0, ocu_max_len);
 303         ocu[0] = 8;
 304         max_val = 0xff;
 305         u_ch = 1;
 306
 307 try_again:
 308         u_len = 1;
 309         for (i = 0; i < str_len; i++) {
 310                 /* Name didn't fit? */
 311                 if (u_len + u_ch > ocu_max_len)
 312                         return 0;
 313                 len = conv_f(&str_i[i], str_len - i, &uni_char);
 314                 if (!len)
 315                         continue;
 316                 /* Invalid character, deal with it */
 317                 if (len < 0) {
 318                         len = 1;
 319                         uni_char = '?';
 320                 }
 321
 322                 if (uni_char > max_val) {
 323                         max_val = 0xffff;
 324                         ocu[0] = 0x10;
 325                         u_ch = 2;
 326                         goto try_again;
 327                 }
 328
 329                 if (max_val == 0xffff)
 330                         ocu[u_len++] = (uint8_t)(uni_char >> 8);
 331                 ocu[u_len++] = (uint8_t)(uni_char & 0xff);
 332                 i += len - 1;
 333         }
 334
 335         return u_len;
 336 }
 337
 338 int udf_dstrCS0toUTF8(uint8_t *utf_o, int o_len,
 339                       const uint8_t *ocu_i, int i_len)
 340 {
 341         int s_len = 0;
 342
 343         if (i_len > 0) {
 344                 s_len = ocu_i[i_len - 1];
 345                 if (s_len >= i_len) {
 346                         pr_err("incorrect dstring lengths (%d/%d)\n",
 347                                s_len, i_len);
 348                         return -EINVAL;
 349                 }
 350         }
 351
 352         return udf_name_from_CS0(utf_o, o_len, ocu_i, s_len,
 353                                  udf_uni2char_utf8, 0);
 354 }
 355
 356 int udf_get_filename(struct super_block *sb, const uint8_t *sname, int slen,
 357                      uint8_t *dname, int dlen)
 358 {
 359         int (*conv_f)(wchar_t, unsigned char *, int);
 360         int ret;
 361
 362         if (!slen)
 363                 return -EIO;
 364
 365         if (dlen <= 0)
 366                 return 0;
 367
 368         if (UDF_QUERY_FLAG(sb, UDF_FLAG_UTF8)) {
 369                 conv_f = udf_uni2char_utf8;
 370         } else if (UDF_QUERY_FLAG(sb, UDF_FLAG_NLS_MAP)) {
 371                 conv_f = UDF_SB(sb)->s_nls_map->uni2char;
 372         } else
 373                 BUG();
 374
 375         ret = udf_name_from_CS0(dname, dlen, sname, slen, conv_f, 1);
 376         /* Zero length filename isn't valid... */
 377         if (ret == 0)
 378                 ret = -EINVAL;
 379         return ret;
 380 }
 381
 382 int udf_put_filename(struct super_block *sb, const uint8_t *sname, int slen,
 383                      uint8_t *dname, int dlen)
 384 {
 385         int (*conv_f)(const unsigned char *, int, wchar_t *);
 386
 387         if (UDF_QUERY_FLAG(sb, UDF_FLAG_UTF8)) {
 388                 conv_f = udf_char2uni_utf8;
 389         } else if (UDF_QUERY_FLAG(sb, UDF_FLAG_NLS_MAP)) {
 390                 conv_f = UDF_SB(sb)->s_nls_map->char2uni;
 391         } else
 392                 BUG();
 393
 394         return udf_name_to_CS0(dname, dlen, sname, slen, conv_f);
 395 }
 396