diff options
Diffstat (limited to 'fs/udf/unicode.c')
| -rw-r--r-- | fs/udf/unicode.c | 398 |
1 files changed, 398 insertions, 0 deletions
diff --git a/fs/udf/unicode.c b/fs/udf/unicode.c new file mode 100644 index 0000000000..32c7f3d27f --- /dev/null +++ b/fs/udf/unicode.c @@ -0,0 +1,398 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * unicode.c + * + * PURPOSE + * Routines for converting between UTF-8 and OSTA Compressed Unicode. + * Also handles filename mangling + * + * DESCRIPTION + * OSTA Compressed Unicode is explained in the OSTA UDF specification. + * http://www.osta.org/ + * UTF-8 is explained in the IETF RFC XXXX. + * ftp://ftp.internic.net/rfc/rfcxxxx.txt + * + */ + +#include "udfdecl.h" + +#include <linux/kernel.h> +#include <linux/string.h> /* for memset */ +#include <linux/nls.h> +#include <linux/crc-itu-t.h> +#include <linux/slab.h> + +#include "udf_sb.h" + +#define PLANE_SIZE 0x10000 +#define UNICODE_MAX 0x10ffff +#define SURROGATE_MASK 0xfffff800 +#define SURROGATE_PAIR 0x0000d800 +#define SURROGATE_LOW 0x00000400 +#define SURROGATE_CHAR_BITS 10 +#define SURROGATE_CHAR_MASK ((1 << SURROGATE_CHAR_BITS) - 1) + +#define ILLEGAL_CHAR_MARK '_' +#define EXT_MARK '.' +#define CRC_MARK '#' +#define EXT_SIZE 5 +/* Number of chars we need to store generated CRC to make filename unique */ +#define CRC_LEN 5 + +static unicode_t get_utf16_char(const uint8_t *str_i, int str_i_max_len, + int str_i_idx, int u_ch, unicode_t *ret) +{ + unicode_t c; + int start_idx = str_i_idx; + + /* Expand OSTA compressed Unicode to Unicode */ + c = str_i[str_i_idx++]; + if (u_ch > 1) + c = (c << 8) | str_i[str_i_idx++]; + if ((c & SURROGATE_MASK) == SURROGATE_PAIR) { + unicode_t next; + + /* Trailing surrogate char */ + if (str_i_idx >= str_i_max_len) { + c = UNICODE_MAX + 1; + goto out; + } + + /* Low surrogate must follow the high one... */ + if (c & SURROGATE_LOW) { + c = UNICODE_MAX + 1; + goto out; + } + + WARN_ON_ONCE(u_ch != 2); + next = str_i[str_i_idx++] << 8; + next |= str_i[str_i_idx++]; + if ((next & SURROGATE_MASK) != SURROGATE_PAIR || + !(next & SURROGATE_LOW)) { + c = UNICODE_MAX + 1; + goto out; + } + + c = PLANE_SIZE + + ((c & SURROGATE_CHAR_MASK) << SURROGATE_CHAR_BITS) + + (next & SURROGATE_CHAR_MASK); + } +out: + *ret = c; + return str_i_idx - start_idx; +} + + +static int 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) +{ + unicode_t c; + int illChar = 0; + int len, gotch = 0; + + while (!gotch && *str_i_idx < str_i_max_len) { + if (*str_o_idx >= str_o_max_len) { + *needsCRC = 1; + return gotch; + } + + len = get_utf16_char(str_i, str_i_max_len, *str_i_idx, u_ch, + &c); + /* These chars cannot be converted. Replace them. */ + if (c == 0 || c > UNICODE_MAX || (conv_f && c > MAX_WCHAR_T) || + (translate && c == '/')) { + illChar = 1; + if (!translate) + gotch = 1; + } else if (illChar) + break; + else + gotch = 1; + *str_i_idx += len; + } + if (illChar) { + *needsCRC = 1; + c = ILLEGAL_CHAR_MARK; + gotch = 1; + } + if (gotch) { + if (conv_f) { + len = conv_f(c, &str_o[*str_o_idx], + str_o_max_len - *str_o_idx); + } else { + len = utf32_to_utf8(c, &str_o[*str_o_idx], + str_o_max_len - *str_o_idx); + if (len < 0) + len = -ENAMETOOLONG; + } + /* Valid character? */ + if (len >= 0) + *str_o_idx += len; + else if (len == -ENAMETOOLONG) { + *needsCRC = 1; + gotch = 0; + } else { + str_o[(*str_o_idx)++] = ILLEGAL_CHAR_MARK; + *needsCRC = 1; + } + } + return gotch; +} + +static int 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) +{ + uint32_t c; + uint8_t cmp_id; + int idx, len; + int u_ch; + int needsCRC = 0; + int ext_i_len, ext_max_len; + int str_o_len = 0; /* Length of resulting output */ + int ext_o_len = 0; /* Extension output length */ + int ext_crc_len = 0; /* Extension output length if used with CRC */ + int i_ext = -1; /* Extension position in input buffer */ + int o_crc = 0; /* Rightmost possible output pos for CRC+ext */ + unsigned short valueCRC; + uint8_t ext[EXT_SIZE * NLS_MAX_CHARSET_SIZE + 1]; + uint8_t crc[CRC_LEN]; + int (*conv_f)(wchar_t, unsigned char *, int); + + if (str_max_len <= 0) + return 0; + + if (ocu_len == 0) { + memset(str_o, 0, str_max_len); + return 0; + } + + if (UDF_SB(sb)->s_nls_map) + conv_f = UDF_SB(sb)->s_nls_map->uni2char; + else + conv_f = NULL; + + cmp_id = ocu[0]; + if (cmp_id != 8 && cmp_id != 16) { + memset(str_o, 0, str_max_len); + pr_err("unknown compression code (%u)\n", cmp_id); + return -EINVAL; + } + u_ch = cmp_id >> 3; + + ocu++; + ocu_len--; + + if (ocu_len % u_ch) { + pr_err("incorrect filename length (%d)\n", ocu_len + 1); + return -EINVAL; + } + + if (translate) { + /* Look for extension */ + for (idx = ocu_len - u_ch, ext_i_len = 0; + (idx >= 0) && (ext_i_len < EXT_SIZE); + idx -= u_ch, ext_i_len++) { + c = ocu[idx]; + if (u_ch > 1) + c = (c << 8) | ocu[idx + 1]; + + if (c == EXT_MARK) { + if (ext_i_len) + i_ext = idx; + break; + } + } + if (i_ext >= 0) { + /* Convert extension */ + ext_max_len = min_t(int, sizeof(ext), str_max_len); + ext[ext_o_len++] = EXT_MARK; + idx = i_ext + u_ch; + while (udf_name_conv_char(ext, ext_max_len, &ext_o_len, + ocu, ocu_len, &idx, + u_ch, &needsCRC, + conv_f, translate)) { + if ((ext_o_len + CRC_LEN) < str_max_len) + ext_crc_len = ext_o_len; + } + } + } + + idx = 0; + while (1) { + if (translate && (idx == i_ext)) { + if (str_o_len > (str_max_len - ext_o_len)) + needsCRC = 1; + break; + } + + if (!udf_name_conv_char(str_o, str_max_len, &str_o_len, + ocu, ocu_len, &idx, + u_ch, &needsCRC, conv_f, translate)) + break; + + if (translate && + (str_o_len <= (str_max_len - ext_o_len - CRC_LEN))) + o_crc = str_o_len; + } + + if (translate) { + if (str_o_len > 0 && str_o_len <= 2 && str_o[0] == '.' && + (str_o_len == 1 || str_o[1] == '.')) + needsCRC = 1; + if (needsCRC) { + str_o_len = o_crc; + valueCRC = crc_itu_t(0, ocu, ocu_len); + crc[0] = CRC_MARK; + crc[1] = hex_asc_upper_hi(valueCRC >> 8); + crc[2] = hex_asc_upper_lo(valueCRC >> 8); + crc[3] = hex_asc_upper_hi(valueCRC); + crc[4] = hex_asc_upper_lo(valueCRC); + len = min_t(int, CRC_LEN, str_max_len - str_o_len); + memcpy(&str_o[str_o_len], crc, len); + str_o_len += len; + ext_o_len = ext_crc_len; + } + if (ext_o_len > 0) { + memcpy(&str_o[str_o_len], ext, ext_o_len); + str_o_len += ext_o_len; + } + } + + return str_o_len; +} + +static int udf_name_to_CS0(struct super_block *sb, + uint8_t *ocu, int ocu_max_len, + const uint8_t *str_i, int str_len) +{ + int i, len; + unsigned int max_val; + int u_len, u_ch; + unicode_t uni_char; + int (*conv_f)(const unsigned char *, int, wchar_t *); + + if (ocu_max_len <= 0) + return 0; + + if (UDF_SB(sb)->s_nls_map) + conv_f = UDF_SB(sb)->s_nls_map->char2uni; + else + conv_f = NULL; + + memset(ocu, 0, ocu_max_len); + ocu[0] = 8; + max_val = 0xff; + u_ch = 1; + +try_again: + u_len = 1; + for (i = 0; i < str_len; i += len) { + /* Name didn't fit? */ + if (u_len + u_ch > ocu_max_len) + return 0; + if (conv_f) { + wchar_t wchar; + + len = conv_f(&str_i[i], str_len - i, &wchar); + if (len > 0) + uni_char = wchar; + } else { + len = utf8_to_utf32(&str_i[i], str_len - i, + &uni_char); + } + /* Invalid character, deal with it */ + if (len <= 0 || uni_char > UNICODE_MAX) { + len = 1; + uni_char = '?'; + } + + if (uni_char > max_val) { + unicode_t c; + + if (max_val == 0xff) { + max_val = 0xffff; + ocu[0] = 0x10; + u_ch = 2; + goto try_again; + } + /* + * Use UTF-16 encoding for chars outside we + * cannot encode directly. + */ + if (u_len + 2 * u_ch > ocu_max_len) + return 0; + + uni_char -= PLANE_SIZE; + c = SURROGATE_PAIR | + ((uni_char >> SURROGATE_CHAR_BITS) & + SURROGATE_CHAR_MASK); + ocu[u_len++] = (uint8_t)(c >> 8); + ocu[u_len++] = (uint8_t)(c & 0xff); + uni_char = SURROGATE_PAIR | SURROGATE_LOW | + (uni_char & SURROGATE_CHAR_MASK); + } + + if (max_val == 0xffff) + ocu[u_len++] = (uint8_t)(uni_char >> 8); + ocu[u_len++] = (uint8_t)(uni_char & 0xff); + } + + return u_len; +} + +/* + * Convert CS0 dstring to output charset. Warning: This function may truncate + * input string if it is too long as it is used for informational strings only + * and it is better to truncate the string than to refuse mounting a media. + */ +int udf_dstrCS0toChar(struct super_block *sb, uint8_t *utf_o, int o_len, + const uint8_t *ocu_i, int i_len) +{ + int s_len = 0; + + if (i_len > 0) { + s_len = ocu_i[i_len - 1]; + if (s_len >= i_len) { + pr_warn("incorrect dstring lengths (%d/%d)," + " truncating\n", s_len, i_len); + s_len = i_len - 1; + /* 2-byte encoding? Need to round properly... */ + if (ocu_i[0] == 16) + s_len -= (s_len - 1) & 2; + } + } + + return udf_name_from_CS0(sb, utf_o, o_len, ocu_i, s_len, 0); +} + +int udf_get_filename(struct super_block *sb, const uint8_t *sname, int slen, + uint8_t *dname, int dlen) +{ + int ret; + + if (!slen) + return -EIO; + + if (dlen <= 0) + return 0; + + ret = udf_name_from_CS0(sb, dname, dlen, sname, slen, 1); + /* Zero length filename isn't valid... */ + if (ret == 0) + ret = -EINVAL; + return ret; +} + +int udf_put_filename(struct super_block *sb, const uint8_t *sname, int slen, + uint8_t *dname, int dlen) +{ + return udf_name_to_CS0(sb, dname, dlen, sname, slen); +} + |