Line data    Source code

       1             : /*
       2             :  *  Copyright (C) 1999 Tom Tromey
       3             :  *  Copyright (C) 2000 Red Hat, Inc.
       4             :  *  Copyright (C) 2004-2024 Savoir-faire Linux Inc.
       5             :  *
       6             :  *  Author: Pascal Potvin <pascal.potvin@extenway.com>
       7             :  *
       8             :  *  This program is free software: you can redistribute it and/or modify
       9             :  *  it under the terms of the GNU General Public License as published by
      10             :  *  the Free Software Foundation, either version 3 of the License, or
      11             :  *  (at your option) any later version.
      12             :  *
      13             :  *  This program is distributed in the hope that it will be useful,
      14             :  *  but WITHOUT ANY WARRANTY; without even the implied warranty of
      15             :  *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
      16             :  *  GNU General Public License for more details.
      17             :  *
      18             :  *  You should have received a copy of the GNU General Public License
      19             :  *  along with this program. If not, see <https://www.gnu.org/licenses/>.
      20             :  */
      21             : 
      22             : #include <cstring>
      23             : #include <cassert>
      24             : #include "connectivity/utf8_utils.h"
      25             : 
      26             : #if defined(_MSC_VER)
      27             : #include <BaseTsd.h>
      28             : using ssize_t = SSIZE_T;
      29             : #endif
      30             : 
      31             : /*
      32             :  * The LIKELY and UNLIKELY macros let the programmer give hints to
      33             :  * the compiler about the expected result of an expression. Some compilers
      34             :  * can use this information for optimizations.
      35             :  */
      36             : #if defined(__GNUC__) && (__GNUC__ > 2) && defined(__OPTIMIZE__)
      37             : #define LIKELY(expr)   (__builtin_expect(expr, 1))
      38             : #define UNLIKELY(expr) (__builtin_expect(expr, 0))
      39             : #else
      40             : #define LIKELY(expr)   (expr)
      41             : #define UNLIKELY(expr) (expr)
      42             : #endif
      43             : 
      44             : /*
      45             :  * Check whether a Unicode (5.2) char is in a valid range.
      46             :  *
      47             :  * The first check comes from the Unicode guarantee to never encode
      48             :  * a point above 0x0010ffff, since UTF-16 is unable to represent it.
      49             :  *
      50             :  * The second check covers surrogate pairs (category Cs).
      51             :  *
      52             :  * @param Char the character
      53             :  */
      54             : #define UNICODE_VALID(Char) ((Char) < 0x110000 && (((Char) &0xFFFFF800) != 0xD800))
      55             : 
      56             : #define CONTINUATION_CHAR \
      57             :     if ((*(unsigned char*) p & 0xc0) != 0x80) /* 10xxxxxx */ \
      58             :         goto error; \
      59             :     val <<= 6; \
      60             :     val |= (*(unsigned char*) p) & 0x3f;
      61             : 
      62             : namespace jami {
      63             : 
      64             : bool utf8_validate_c_str(const char* str, ssize_t max_len, const char** end);
      65             : 
      66             : static const char*
      67           0 : fast_validate(const char* str)
      68             : {
      69           0 :     char32_t val = 0;
      70           0 :     char32_t min = 0;
      71             :     const char* p;
      72             : 
      73           0 :     for (p = str; *p; p++) {
      74           0 :         if (*(unsigned char*) p < 128)
      75             :             /* done */;
      76             :         else {
      77             :             const char* last;
      78             : 
      79           0 :             last = p;
      80             : 
      81           0 :             if ((*(unsigned char*) p & 0xe0) == 0xc0) { /* 110xxxxx */
      82           0 :                 if (UNLIKELY((*(unsigned char*) p & 0x1e) == 0))
      83           0 :                     goto error;
      84             : 
      85           0 :                 p++;
      86             : 
      87           0 :                 if (UNLIKELY((*(unsigned char*) p & 0xc0) != 0x80)) /* 10xxxxxx */
      88           0 :                     goto error;
      89             :             } else {
      90           0 :                 if ((*(unsigned char*) p & 0xf0) == 0xe0) { /* 1110xxxx */
      91           0 :                     min = (1 << 11);
      92           0 :                     val = *(unsigned char*) p & 0x0f;
      93           0 :                     goto TWO_REMAINING;
      94           0 :                 } else if ((*(unsigned char*) p & 0xf8) == 0xf0) { /* 11110xxx */
      95           0 :                     min = (1 << 16);
      96           0 :                     val = *(unsigned char*) p & 0x07;
      97             :                 } else
      98           0 :                     goto error;
      99             : 
     100           0 :                 p++;
     101           0 :                 CONTINUATION_CHAR;
     102           0 :             TWO_REMAINING:
     103           0 :                 p++;
     104           0 :                 CONTINUATION_CHAR;
     105           0 :                 p++;
     106           0 :                 CONTINUATION_CHAR;
     107             : 
     108           0 :                 if (UNLIKELY(val < min))
     109           0 :                     goto error;
     110             : 
     111           0 :                 if (UNLIKELY(!UNICODE_VALID(val)))
     112           0 :                     goto error;
     113             :             }
     114             : 
     115           0 :             continue;
     116             : 
     117           0 :         error:
     118           0 :             return last;
     119           0 :         }
     120             :     }
     121             : 
     122           0 :     return p;
     123             : }
     124             : 
     125             : static const char*
     126         792 : fast_validate_len(const char* str, ssize_t max_len)
     127             : {
     128         792 :     char32_t val = 0;
     129         792 :     char32_t min = 0;
     130             :     const char* p;
     131             : 
     132         792 :     assert(max_len >= 0);
     133             : 
     134       57918 :     for (p = str; ((p - str) < max_len) && *p; p++) {
     135       57126 :         if (*(unsigned char*) p < 128)
     136             :             /* done */;
     137             :         else {
     138             :             const char* last;
     139             : 
     140           0 :             last = p;
     141             : 
     142           0 :             if ((*(unsigned char*) p & 0xe0) == 0xc0) { /* 110xxxxx */
     143           0 :                 if (UNLIKELY(max_len - (p - str) < 2))
     144           0 :                     goto error;
     145             : 
     146           0 :                 if (UNLIKELY((*(unsigned char*) p & 0x1e) == 0))
     147           0 :                     goto error;
     148             : 
     149           0 :                 p++;
     150             : 
     151           0 :                 if (UNLIKELY((*(unsigned char*) p & 0xc0) != 0x80)) /* 10xxxxxx */
     152           0 :                     goto error;
     153             :             } else {
     154           0 :                 if ((*(unsigned char*) p & 0xf0) == 0xe0) { /* 1110xxxx */
     155           0 :                     if (UNLIKELY(max_len - (p - str) < 3))
     156           0 :                         goto error;
     157             : 
     158           0 :                     min = (1 << 11);
     159           0 :                     val = *(unsigned char*) p & 0x0f;
     160           0 :                     goto TWO_REMAINING;
     161           0 :                 } else if ((*(unsigned char*) p & 0xf8) == 0xf0) { /* 11110xxx */
     162           0 :                     if (UNLIKELY(max_len - (p - str) < 4))
     163           0 :                         goto error;
     164             : 
     165           0 :                     min = (1 << 16);
     166           0 :                     val = *(unsigned char*) p & 0x07;
     167             :                 } else
     168           0 :                     goto error;
     169             : 
     170           0 :                 p++;
     171           0 :                 CONTINUATION_CHAR;
     172           0 :             TWO_REMAINING:
     173           0 :                 p++;
     174           0 :                 CONTINUATION_CHAR;
     175           0 :                 p++;
     176           0 :                 CONTINUATION_CHAR;
     177             : 
     178           0 :                 if (UNLIKELY(val < min))
     179           0 :                     goto error;
     180             : 
     181           0 :                 if (UNLIKELY(!UNICODE_VALID(val)))
     182           0 :                     goto error;
     183             :             }
     184             : 
     185           0 :             continue;
     186             : 
     187           0 :         error:
     188           0 :             return last;
     189           0 :         }
     190             :     }
     191             : 
     192         792 :     return p;
     193             : }
     194             : 
     195             : /**
     196             :  * utf8_validate_c_str:
     197             :  * @str: a pointer to character data
     198             :  * @max_len: max bytes to validate, or -1 to go until NULL
     199             :  * @end: return location for end of valid data
     200             :  *
     201             :  * Validates UTF-8 encoded text. @str is the text to validate;
     202             :  * if @str is nul-terminated, then @max_len can be -1, otherwise
     203             :  * @max_len should be the number of bytes to validate.
     204             :  * If @end is non-%NULL, then the end of the valid range
     205             :  * will be stored there (i.e. the start of the first invalid
     206             :  * character if some bytes were invalid, or the end of the text
     207             :  * being validated otherwise).
     208             :  *
     209             :  * Note that utf8_validate() returns %false if @max_len is
     210             :  * positive and any of the @max_len bytes are nul.
     211             :  *
     212             :  * Returns true if all of @str was valid. Dbus requires valid UTF-8 as input;
     213             :  * sip packets should also be encoded in utf8; so data read from a file or the
     214             :  * network should be checked with utf8_validate() before doing anything else
     215             :  * with it.
     216             :  *
     217             :  * Returns: true if the text was valid UTF-8
     218             :  */
     219             : bool
     220         107 : utf8_validate_c_str(const char* str, ssize_t max_len, const char** end)
     221             : {
     222             :     const char* p;
     223             : 
     224         107 :     if (max_len < 0)
     225           0 :         p = fast_validate(str);
     226             :     else
     227         107 :         p = fast_validate_len(str, max_len);
     228             : 
     229         107 :     if (end)
     230         107 :         *end = p;
     231             : 
     232         107 :     if ((max_len >= 0 && p != str + max_len) || (max_len < 0 && *p != '\0'))
     233           0 :         return false;
     234             :     else
     235         107 :         return true;
     236             : }
     237             : 
     238             : bool
     239         685 : utf8_validate(std::string_view str)
     240             : {
     241         685 :     const char* p = fast_validate_len(str.data(), str.size());
     242             : 
     243         685 :     return (*p == '\0');
     244             : }
     245             : 
     246             : std::string
     247         107 : utf8_make_valid(std::string_view name)
     248             : {
     249         107 :     ssize_t remaining_bytes = name.size();
     250             :     ssize_t valid_bytes;
     251         107 :     const char* remainder = name.data();
     252             :     const char* invalid;
     253         107 :     char* str = NULL;
     254             :     char* pos;
     255             : 
     256         107 :     while (remaining_bytes != 0) {
     257         107 :         if (utf8_validate_c_str(remainder, remaining_bytes, &invalid))
     258         107 :             break;
     259             : 
     260           0 :         valid_bytes = invalid - remainder;
     261             : 
     262           0 :         if (str == NULL)
     263             :             // If every byte is replaced by U+FFFD, max(strlen(string)) == 3 * name.size()
     264           0 :             str = new char[3 * remaining_bytes];
     265             : 
     266           0 :         pos = str;
     267             : 
     268           0 :         strncpy(pos, remainder, valid_bytes);
     269           0 :         pos += valid_bytes;
     270             : 
     271             :         /* append U+FFFD REPLACEMENT CHARACTER */
     272           0 :         pos[0] = '\357';
     273           0 :         pos[1] = '\277';
     274           0 :         pos[2] = '\275';
     275             : 
     276           0 :         pos += 3;
     277             : 
     278           0 :         remaining_bytes -= valid_bytes + 1;
     279           0 :         remainder = invalid + 1;
     280             :     }
     281             : 
     282         107 :     if (str == NULL)
     283         107 :         return std::string(name);
     284             : 
     285           0 :     strncpy(pos, remainder, remaining_bytes);
     286           0 :     pos += remaining_bytes;
     287             : 
     288           0 :     std::string answer(str, pos - str);
     289           0 :     assert(utf8_validate(answer));
     290             : 
     291           0 :     delete[] str;
     292             : 
     293           0 :     return answer;
     294           0 : }
     295             : 
     296             : } // namespace jami