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1// SPDX-License-Identifier: GPL-2.0-only2/*3 * unicode.c4 *5 * PURPOSE6 * Routines for converting between UTF-8 and OSTA Compressed Unicode.7 * Also handles filename mangling8 *9 * DESCRIPTION10 * OSTA Compressed Unicode is explained in the OSTA UDF specification.11 * http://www.osta.org/12 * UTF-8 is explained in the IETF RFC XXXX.13 * ftp://ftp.internic.net/rfc/rfcxxxx.txt14 *15 */16 17#include "udfdecl.h"18 19#include <linux/kernel.h>20#include <linux/string.h> /* for memset */21#include <linux/nls.h>22#include <linux/crc-itu-t.h>23#include <linux/slab.h>24 25#include "udf_sb.h"26 27#define PLANE_SIZE 0x1000028#define UNICODE_MAX 0x10ffff29#define SURROGATE_MASK 0xfffff80030#define SURROGATE_PAIR 0x0000d80031#define SURROGATE_LOW 0x0000040032#define SURROGATE_CHAR_BITS 1033#define SURROGATE_CHAR_MASK ((1 << SURROGATE_CHAR_BITS) - 1)34 35#define ILLEGAL_CHAR_MARK '_'36#define EXT_MARK '.'37#define CRC_MARK '#'38#define EXT_SIZE 539/* Number of chars we need to store generated CRC to make filename unique */40#define CRC_LEN 541 42static unicode_t get_utf16_char(const uint8_t *str_i, int str_i_max_len,43 int str_i_idx, int u_ch, unicode_t *ret)44{45 unicode_t c;46 int start_idx = str_i_idx;47 48 /* Expand OSTA compressed Unicode to Unicode */49 c = str_i[str_i_idx++];50 if (u_ch > 1)51 c = (c << 8) | str_i[str_i_idx++];52 if ((c & SURROGATE_MASK) == SURROGATE_PAIR) {53 unicode_t next;54 55 /* Trailing surrogate char */56 if (str_i_idx >= str_i_max_len) {57 c = UNICODE_MAX + 1;58 goto out;59 }60 61 /* Low surrogate must follow the high one... */62 if (c & SURROGATE_LOW) {63 c = UNICODE_MAX + 1;64 goto out;65 }66 67 WARN_ON_ONCE(u_ch != 2);68 next = str_i[str_i_idx++] << 8;69 next |= str_i[str_i_idx++];70 if ((next & SURROGATE_MASK) != SURROGATE_PAIR ||71 !(next & SURROGATE_LOW)) {72 c = UNICODE_MAX + 1;73 goto out;74 }75 76 c = PLANE_SIZE +77 ((c & SURROGATE_CHAR_MASK) << SURROGATE_CHAR_BITS) +78 (next & SURROGATE_CHAR_MASK);79 }80out:81 *ret = c;82 return str_i_idx - start_idx;83}84 85 86static int udf_name_conv_char(uint8_t *str_o, int str_o_max_len,87 int *str_o_idx,88 const uint8_t *str_i, int str_i_max_len,89 int *str_i_idx,90 int u_ch, int *needsCRC,91 int (*conv_f)(wchar_t, unsigned char *, int),92 int translate)93{94 unicode_t c;95 int illChar = 0;96 int len, gotch = 0;97 98 while (!gotch && *str_i_idx < str_i_max_len) {99 if (*str_o_idx >= str_o_max_len) {100 *needsCRC = 1;101 return gotch;102 }103 104 len = get_utf16_char(str_i, str_i_max_len, *str_i_idx, u_ch,105 &c);106 /* These chars cannot be converted. Replace them. */107 if (c == 0 || c > UNICODE_MAX || (conv_f && c > MAX_WCHAR_T) ||108 (translate && c == '/')) {109 illChar = 1;110 if (!translate)111 gotch = 1;112 } else if (illChar)113 break;114 else115 gotch = 1;116 *str_i_idx += len;117 }118 if (illChar) {119 *needsCRC = 1;120 c = ILLEGAL_CHAR_MARK;121 gotch = 1;122 }123 if (gotch) {124 if (conv_f) {125 len = conv_f(c, &str_o[*str_o_idx],126 str_o_max_len - *str_o_idx);127 } else {128 len = utf32_to_utf8(c, &str_o[*str_o_idx],129 str_o_max_len - *str_o_idx);130 if (len < 0)131 len = -ENAMETOOLONG;132 }133 /* Valid character? */134 if (len >= 0)135 *str_o_idx += len;136 else if (len == -ENAMETOOLONG) {137 *needsCRC = 1;138 gotch = 0;139 } else {140 str_o[(*str_o_idx)++] = ILLEGAL_CHAR_MARK;141 *needsCRC = 1;142 }143 }144 return gotch;145}146 147static int udf_name_from_CS0(struct super_block *sb,148 uint8_t *str_o, int str_max_len,149 const uint8_t *ocu, int ocu_len,150 int translate)151{152 uint32_t c;153 uint8_t cmp_id;154 int idx, len;155 int u_ch;156 int needsCRC = 0;157 int ext_i_len, ext_max_len;158 int str_o_len = 0; /* Length of resulting output */159 int ext_o_len = 0; /* Extension output length */160 int ext_crc_len = 0; /* Extension output length if used with CRC */161 int i_ext = -1; /* Extension position in input buffer */162 int o_crc = 0; /* Rightmost possible output pos for CRC+ext */163 unsigned short valueCRC;164 uint8_t ext[EXT_SIZE * NLS_MAX_CHARSET_SIZE + 1];165 uint8_t crc[CRC_LEN];166 int (*conv_f)(wchar_t, unsigned char *, int);167 168 if (str_max_len <= 0)169 return 0;170 171 if (ocu_len == 0) {172 memset(str_o, 0, str_max_len);173 return 0;174 }175 176 if (UDF_SB(sb)->s_nls_map)177 conv_f = UDF_SB(sb)->s_nls_map->uni2char;178 else179 conv_f = NULL;180 181 cmp_id = ocu[0];182 if (cmp_id != 8 && cmp_id != 16) {183 memset(str_o, 0, str_max_len);184 pr_err("unknown compression code (%u)\n", cmp_id);185 return -EINVAL;186 }187 u_ch = cmp_id >> 3;188 189 ocu++;190 ocu_len--;191 192 if (ocu_len % u_ch) {193 pr_err("incorrect filename length (%d)\n", ocu_len + 1);194 return -EINVAL;195 }196 197 if (translate) {198 /* Look for extension */199 for (idx = ocu_len - u_ch, ext_i_len = 0;200 (idx >= 0) && (ext_i_len < EXT_SIZE);201 idx -= u_ch, ext_i_len++) {202 c = ocu[idx];203 if (u_ch > 1)204 c = (c << 8) | ocu[idx + 1];205 206 if (c == EXT_MARK) {207 if (ext_i_len)208 i_ext = idx;209 break;210 }211 }212 if (i_ext >= 0) {213 /* Convert extension */214 ext_max_len = min_t(int, sizeof(ext), str_max_len);215 ext[ext_o_len++] = EXT_MARK;216 idx = i_ext + u_ch;217 while (udf_name_conv_char(ext, ext_max_len, &ext_o_len,218 ocu, ocu_len, &idx,219 u_ch, &needsCRC,220 conv_f, translate)) {221 if ((ext_o_len + CRC_LEN) < str_max_len)222 ext_crc_len = ext_o_len;223 }224 }225 }226 227 idx = 0;228 while (1) {229 if (translate && (idx == i_ext)) {230 if (str_o_len > (str_max_len - ext_o_len))231 needsCRC = 1;232 break;233 }234 235 if (!udf_name_conv_char(str_o, str_max_len, &str_o_len,236 ocu, ocu_len, &idx,237 u_ch, &needsCRC, conv_f, translate))238 break;239 240 if (translate &&241 (str_o_len <= (str_max_len - ext_o_len - CRC_LEN)))242 o_crc = str_o_len;243 }244 245 if (translate) {246 if (str_o_len > 0 && str_o_len <= 2 && str_o[0] == '.' &&247 (str_o_len == 1 || str_o[1] == '.'))248 needsCRC = 1;249 if (needsCRC) {250 str_o_len = o_crc;251 valueCRC = crc_itu_t(0, ocu, ocu_len);252 crc[0] = CRC_MARK;253 crc[1] = hex_asc_upper_hi(valueCRC >> 8);254 crc[2] = hex_asc_upper_lo(valueCRC >> 8);255 crc[3] = hex_asc_upper_hi(valueCRC);256 crc[4] = hex_asc_upper_lo(valueCRC);257 len = min_t(int, CRC_LEN, str_max_len - str_o_len);258 memcpy(&str_o[str_o_len], crc, len);259 str_o_len += len;260 ext_o_len = ext_crc_len;261 }262 if (ext_o_len > 0) {263 memcpy(&str_o[str_o_len], ext, ext_o_len);264 str_o_len += ext_o_len;265 }266 }267 268 return str_o_len;269}270 271static int udf_name_to_CS0(struct super_block *sb,272 uint8_t *ocu, int ocu_max_len,273 const uint8_t *str_i, int str_len)274{275 int i, len;276 unsigned int max_val;277 int u_len, u_ch;278 unicode_t uni_char;279 int (*conv_f)(const unsigned char *, int, wchar_t *);280 281 if (ocu_max_len <= 0)282 return 0;283 284 if (UDF_SB(sb)->s_nls_map)285 conv_f = UDF_SB(sb)->s_nls_map->char2uni;286 else287 conv_f = NULL;288 289 memset(ocu, 0, ocu_max_len);290 ocu[0] = 8;291 max_val = 0xff;292 u_ch = 1;293 294try_again:295 u_len = 1;296 for (i = 0; i < str_len; i += len) {297 /* Name didn't fit? */298 if (u_len + u_ch > ocu_max_len)299 return 0;300 if (conv_f) {301 wchar_t wchar;302 303 len = conv_f(&str_i[i], str_len - i, &wchar);304 if (len > 0)305 uni_char = wchar;306 } else {307 len = utf8_to_utf32(&str_i[i], str_len - i,308 &uni_char);309 }310 /* Invalid character, deal with it */311 if (len <= 0 || uni_char > UNICODE_MAX) {312 len = 1;313 uni_char = '?';314 }315 316 if (uni_char > max_val) {317 unicode_t c;318 319 if (max_val == 0xff) {320 max_val = 0xffff;321 ocu[0] = 0x10;322 u_ch = 2;323 goto try_again;324 }325 /*326 * Use UTF-16 encoding for chars outside we327 * cannot encode directly.328 */329 if (u_len + 2 * u_ch > ocu_max_len)330 return 0;331 332 uni_char -= PLANE_SIZE;333 c = SURROGATE_PAIR |334 ((uni_char >> SURROGATE_CHAR_BITS) &335 SURROGATE_CHAR_MASK);336 ocu[u_len++] = (uint8_t)(c >> 8);337 ocu[u_len++] = (uint8_t)(c & 0xff);338 uni_char = SURROGATE_PAIR | SURROGATE_LOW |339 (uni_char & SURROGATE_CHAR_MASK);340 }341 342 if (max_val == 0xffff)343 ocu[u_len++] = (uint8_t)(uni_char >> 8);344 ocu[u_len++] = (uint8_t)(uni_char & 0xff);345 }346 347 return u_len;348}349 350/*351 * Convert CS0 dstring to output charset. Warning: This function may truncate352 * input string if it is too long as it is used for informational strings only353 * and it is better to truncate the string than to refuse mounting a media.354 */355int udf_dstrCS0toChar(struct super_block *sb, uint8_t *utf_o, int o_len,356 const uint8_t *ocu_i, int i_len)357{358 int s_len = 0;359 360 if (i_len > 0) {361 s_len = ocu_i[i_len - 1];362 if (s_len >= i_len) {363 pr_warn("incorrect dstring lengths (%d/%d),"364 " truncating\n", s_len, i_len);365 s_len = i_len - 1;366 /* 2-byte encoding? Need to round properly... */367 if (ocu_i[0] == 16)368 s_len -= (s_len - 1) & 2;369 }370 }371 372 return udf_name_from_CS0(sb, utf_o, o_len, ocu_i, s_len, 0);373}374 375int udf_get_filename(struct super_block *sb, const uint8_t *sname, int slen,376 uint8_t *dname, int dlen)377{378 int ret;379 380 if (!slen)381 return -EIO;382 383 if (dlen <= 0)384 return 0;385 386 ret = udf_name_from_CS0(sb, dname, dlen, sname, slen, 1);387 /* Zero length filename isn't valid... */388 if (ret == 0)389 ret = -EINVAL;390 return ret;391}392 393int udf_put_filename(struct super_block *sb, const uint8_t *sname, int slen,394 uint8_t *dname, int dlen)395{396 return udf_name_to_CS0(sb, dname, dlen, sname, slen);397}398 399