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 #define PLANE_SIZE 0x10000
32 #define UNICODE_MAX 0x10ffff
33 #define SURROGATE_MASK 0xfffff800
34 #define SURROGATE_PAIR 0x0000d800
35 #define SURROGATE_LOW 0x00000400
36 #define SURROGATE_CHAR_BITS 10
37 #define SURROGATE_CHAR_MASK ((1 << SURROGATE_CHAR_BITS) - 1)
38
39 #define ILLEGAL_CHAR_MARK '_'
40 #define EXT_MARK '.'
41 #define CRC_MARK '#'
42 #define EXT_SIZE 5
43 /* Number of chars we need to store generated CRC to make filename unique */
44 #define CRC_LEN 5
45
get_utf16_char(const uint8_t * str_i,int str_i_max_len,int str_i_idx,int u_ch,unicode_t * ret)46 static unicode_t get_utf16_char(const uint8_t *str_i, int str_i_max_len,
47 int str_i_idx, int u_ch, unicode_t *ret)
48 {
49 unicode_t c;
50 int start_idx = str_i_idx;
51
52 /* Expand OSTA compressed Unicode to Unicode */
53 c = str_i[str_i_idx++];
54 if (u_ch > 1)
55 c = (c << 8) | str_i[str_i_idx++];
56 if ((c & SURROGATE_MASK) == SURROGATE_PAIR) {
57 unicode_t next;
58
59 /* Trailing surrogate char */
60 if (str_i_idx >= str_i_max_len) {
61 c = UNICODE_MAX + 1;
62 goto out;
63 }
64
65 /* Low surrogate must follow the high one... */
66 if (c & SURROGATE_LOW) {
67 c = UNICODE_MAX + 1;
68 goto out;
69 }
70
71 WARN_ON_ONCE(u_ch != 2);
72 next = str_i[str_i_idx++] << 8;
73 next |= str_i[str_i_idx++];
74 if ((next & SURROGATE_MASK) != SURROGATE_PAIR ||
75 !(next & SURROGATE_LOW)) {
76 c = UNICODE_MAX + 1;
77 goto out;
78 }
79
80 c = PLANE_SIZE +
81 ((c & SURROGATE_CHAR_MASK) << SURROGATE_CHAR_BITS) +
82 (next & SURROGATE_CHAR_MASK);
83 }
84 out:
85 *ret = c;
86 return str_i_idx - start_idx;
87 }
88
89
udf_name_conv_char(uint8_t * str_o,int str_o_max_len,int * str_o_idx,const uint8_t * str_i,int str_i_max_len,int * str_i_idx,int u_ch,int * needsCRC,int (* conv_f)(wchar_t,unsigned char *,int),int translate)90 static int udf_name_conv_char(uint8_t *str_o, int str_o_max_len,
91 int *str_o_idx,
92 const uint8_t *str_i, int str_i_max_len,
93 int *str_i_idx,
94 int u_ch, int *needsCRC,
95 int (*conv_f)(wchar_t, unsigned char *, int),
96 int translate)
97 {
98 unicode_t c;
99 int illChar = 0;
100 int len, gotch = 0;
101
102 while (!gotch && *str_i_idx < str_i_max_len) {
103 if (*str_o_idx >= str_o_max_len) {
104 *needsCRC = 1;
105 return gotch;
106 }
107
108 len = get_utf16_char(str_i, str_i_max_len, *str_i_idx, u_ch,
109 &c);
110 /* These chars cannot be converted. Replace them. */
111 if (c == 0 || c > UNICODE_MAX || (conv_f && c > MAX_WCHAR_T) ||
112 (translate && c == '/')) {
113 illChar = 1;
114 if (!translate)
115 gotch = 1;
116 } else if (illChar)
117 break;
118 else
119 gotch = 1;
120 *str_i_idx += len;
121 }
122 if (illChar) {
123 *needsCRC = 1;
124 c = ILLEGAL_CHAR_MARK;
125 gotch = 1;
126 }
127 if (gotch) {
128 if (conv_f) {
129 len = conv_f(c, &str_o[*str_o_idx],
130 str_o_max_len - *str_o_idx);
131 } else {
132 len = utf32_to_utf8(c, &str_o[*str_o_idx],
133 str_o_max_len - *str_o_idx);
134 if (len < 0)
135 len = -ENAMETOOLONG;
136 }
137 /* Valid character? */
138 if (len >= 0)
139 *str_o_idx += len;
140 else if (len == -ENAMETOOLONG) {
141 *needsCRC = 1;
142 gotch = 0;
143 } else {
144 str_o[(*str_o_idx)++] = ILLEGAL_CHAR_MARK;
145 *needsCRC = 1;
146 }
147 }
148 return gotch;
149 }
150
udf_name_from_CS0(struct super_block * sb,uint8_t * str_o,int str_max_len,const uint8_t * ocu,int ocu_len,int translate)151 static int udf_name_from_CS0(struct super_block *sb,
152 uint8_t *str_o, int str_max_len,
153 const uint8_t *ocu, int ocu_len,
154 int translate)
155 {
156 uint32_t c;
157 uint8_t cmp_id;
158 int idx, len;
159 int u_ch;
160 int needsCRC = 0;
161 int ext_i_len, ext_max_len;
162 int str_o_len = 0; /* Length of resulting output */
163 int ext_o_len = 0; /* Extension output length */
164 int ext_crc_len = 0; /* Extension output length if used with CRC */
165 int i_ext = -1; /* Extension position in input buffer */
166 int o_crc = 0; /* Rightmost possible output pos for CRC+ext */
167 unsigned short valueCRC;
168 uint8_t ext[EXT_SIZE * NLS_MAX_CHARSET_SIZE + 1];
169 uint8_t crc[CRC_LEN];
170 int (*conv_f)(wchar_t, unsigned char *, int);
171
172 if (str_max_len <= 0)
173 return 0;
174
175 if (ocu_len == 0) {
176 memset(str_o, 0, str_max_len);
177 return 0;
178 }
179
180 if (UDF_QUERY_FLAG(sb, UDF_FLAG_NLS_MAP))
181 conv_f = UDF_SB(sb)->s_nls_map->uni2char;
182 else
183 conv_f = NULL;
184
185 cmp_id = ocu[0];
186 if (cmp_id != 8 && cmp_id != 16) {
187 memset(str_o, 0, str_max_len);
188 pr_err("unknown compression code (%u)\n", cmp_id);
189 return -EINVAL;
190 }
191 u_ch = cmp_id >> 3;
192
193 ocu++;
194 ocu_len--;
195
196 if (ocu_len % u_ch) {
197 pr_err("incorrect filename length (%d)\n", ocu_len + 1);
198 return -EINVAL;
199 }
200
201 if (translate) {
202 /* Look for extension */
203 for (idx = ocu_len - u_ch, ext_i_len = 0;
204 (idx >= 0) && (ext_i_len < EXT_SIZE);
205 idx -= u_ch, ext_i_len++) {
206 c = ocu[idx];
207 if (u_ch > 1)
208 c = (c << 8) | ocu[idx + 1];
209
210 if (c == EXT_MARK) {
211 if (ext_i_len)
212 i_ext = idx;
213 break;
214 }
215 }
216 if (i_ext >= 0) {
217 /* Convert extension */
218 ext_max_len = min_t(int, sizeof(ext), str_max_len);
219 ext[ext_o_len++] = EXT_MARK;
220 idx = i_ext + u_ch;
221 while (udf_name_conv_char(ext, ext_max_len, &ext_o_len,
222 ocu, ocu_len, &idx,
223 u_ch, &needsCRC,
224 conv_f, translate)) {
225 if ((ext_o_len + CRC_LEN) < str_max_len)
226 ext_crc_len = ext_o_len;
227 }
228 }
229 }
230
231 idx = 0;
232 while (1) {
233 if (translate && (idx == i_ext)) {
234 if (str_o_len > (str_max_len - ext_o_len))
235 needsCRC = 1;
236 break;
237 }
238
239 if (!udf_name_conv_char(str_o, str_max_len, &str_o_len,
240 ocu, ocu_len, &idx,
241 u_ch, &needsCRC, conv_f, translate))
242 break;
243
244 if (translate &&
245 (str_o_len <= (str_max_len - ext_o_len - CRC_LEN)))
246 o_crc = str_o_len;
247 }
248
249 if (translate) {
250 if (str_o_len <= 2 && str_o[0] == '.' &&
251 (str_o_len == 1 || str_o[1] == '.'))
252 needsCRC = 1;
253 if (needsCRC) {
254 str_o_len = o_crc;
255 valueCRC = crc_itu_t(0, ocu, ocu_len);
256 crc[0] = CRC_MARK;
257 crc[1] = hex_asc_upper_hi(valueCRC >> 8);
258 crc[2] = hex_asc_upper_lo(valueCRC >> 8);
259 crc[3] = hex_asc_upper_hi(valueCRC);
260 crc[4] = hex_asc_upper_lo(valueCRC);
261 len = min_t(int, CRC_LEN, str_max_len - str_o_len);
262 memcpy(&str_o[str_o_len], crc, len);
263 str_o_len += len;
264 ext_o_len = ext_crc_len;
265 }
266 if (ext_o_len > 0) {
267 memcpy(&str_o[str_o_len], ext, ext_o_len);
268 str_o_len += ext_o_len;
269 }
270 }
271
272 return str_o_len;
273 }
274
udf_name_to_CS0(struct super_block * sb,uint8_t * ocu,int ocu_max_len,const uint8_t * str_i,int str_len)275 static int udf_name_to_CS0(struct super_block *sb,
276 uint8_t *ocu, int ocu_max_len,
277 const uint8_t *str_i, int str_len)
278 {
279 int i, len;
280 unsigned int max_val;
281 int u_len, u_ch;
282 unicode_t uni_char;
283 int (*conv_f)(const unsigned char *, int, wchar_t *);
284
285 if (ocu_max_len <= 0)
286 return 0;
287
288 if (UDF_QUERY_FLAG(sb, UDF_FLAG_NLS_MAP))
289 conv_f = UDF_SB(sb)->s_nls_map->char2uni;
290 else
291 conv_f = NULL;
292
293 memset(ocu, 0, ocu_max_len);
294 ocu[0] = 8;
295 max_val = 0xff;
296 u_ch = 1;
297
298 try_again:
299 u_len = 1;
300 for (i = 0; i < str_len; i += len) {
301 /* Name didn't fit? */
302 if (u_len + u_ch > ocu_max_len)
303 return 0;
304 if (conv_f) {
305 wchar_t wchar;
306
307 len = conv_f(&str_i[i], str_len - i, &wchar);
308 if (len > 0)
309 uni_char = wchar;
310 } else {
311 len = utf8_to_utf32(&str_i[i], str_len - i,
312 &uni_char);
313 }
314 /* Invalid character, deal with it */
315 if (len <= 0 || uni_char > UNICODE_MAX) {
316 len = 1;
317 uni_char = '?';
318 }
319
320 if (uni_char > max_val) {
321 unicode_t c;
322
323 if (max_val == 0xff) {
324 max_val = 0xffff;
325 ocu[0] = 0x10;
326 u_ch = 2;
327 goto try_again;
328 }
329 /*
330 * Use UTF-16 encoding for chars outside we
331 * cannot encode directly.
332 */
333 if (u_len + 2 * u_ch > ocu_max_len)
334 return 0;
335
336 uni_char -= PLANE_SIZE;
337 c = SURROGATE_PAIR |
338 ((uni_char >> SURROGATE_CHAR_BITS) &
339 SURROGATE_CHAR_MASK);
340 ocu[u_len++] = (uint8_t)(c >> 8);
341 ocu[u_len++] = (uint8_t)(c & 0xff);
342 uni_char = SURROGATE_PAIR | SURROGATE_LOW |
343 (uni_char & SURROGATE_CHAR_MASK);
344 }
345
346 if (max_val == 0xffff)
347 ocu[u_len++] = (uint8_t)(uni_char >> 8);
348 ocu[u_len++] = (uint8_t)(uni_char & 0xff);
349 }
350
351 return u_len;
352 }
353
354 /*
355 * Convert CS0 dstring to output charset. Warning: This function may truncate
356 * input string if it is too long as it is used for informational strings only
357 * and it is better to truncate the string than to refuse mounting a media.
358 */
udf_dstrCS0toChar(struct super_block * sb,uint8_t * utf_o,int o_len,const uint8_t * ocu_i,int i_len)359 int udf_dstrCS0toChar(struct super_block *sb, uint8_t *utf_o, int o_len,
360 const uint8_t *ocu_i, int i_len)
361 {
362 int s_len = 0;
363
364 if (i_len > 0) {
365 s_len = ocu_i[i_len - 1];
366 if (s_len >= i_len) {
367 pr_warn("incorrect dstring lengths (%d/%d),"
368 " truncating\n", s_len, i_len);
369 s_len = i_len - 1;
370 /* 2-byte encoding? Need to round properly... */
371 if (ocu_i[0] == 16)
372 s_len -= (s_len - 1) & 2;
373 }
374 }
375
376 return udf_name_from_CS0(sb, utf_o, o_len, ocu_i, s_len, 0);
377 }
378
udf_get_filename(struct super_block * sb,const uint8_t * sname,int slen,uint8_t * dname,int dlen)379 int udf_get_filename(struct super_block *sb, const uint8_t *sname, int slen,
380 uint8_t *dname, int dlen)
381 {
382 int ret;
383
384 if (!slen)
385 return -EIO;
386
387 if (dlen <= 0)
388 return 0;
389
390 ret = udf_name_from_CS0(sb, dname, dlen, sname, slen, 1);
391 /* Zero length filename isn't valid... */
392 if (ret == 0)
393 ret = -EINVAL;
394 return ret;
395 }
396
udf_put_filename(struct super_block * sb,const uint8_t * sname,int slen,uint8_t * dname,int dlen)397 int udf_put_filename(struct super_block *sb, const uint8_t *sname, int slen,
398 uint8_t *dname, int dlen)
399 {
400 return udf_name_to_CS0(sb, dname, dlen, sname, slen);
401 }
402
403