1 /************************************************* 2 * Perl-Compatible Regular Expressions * 3 *************************************************/ 4 5 /* PCRE is a library of functions to support regular expressions whose syntax 6 and semantics are as close as possible to those of the Perl 5 language. 7 8 Written by Philip Hazel 9 Copyright (c) 1997-2013 University of Cambridge 10 11 ----------------------------------------------------------------------------- 12 Redistribution and use in source and binary forms, with or without 13 modification, are permitted provided that the following conditions are met: 14 15 * Redistributions of source code must retain the above copyright notice, 16 this list of conditions and the following disclaimer. 17 18 * Redistributions in binary form must reproduce the above copyright 19 notice, this list of conditions and the following disclaimer in the 20 documentation and/or other materials provided with the distribution. 21 22 * Neither the name of the University of Cambridge nor the names of its 23 contributors may be used to endorse or promote products derived from 24 this software without specific prior written permission. 25 26 THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" 27 AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 28 IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 29 ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE 30 LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR 31 CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF 32 SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS 33 INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN 34 CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) 35 ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE 36 POSSIBILITY OF SUCH DAMAGE. 37 ----------------------------------------------------------------------------- 38 */ 39 40 41 /* This module contains an internal function for validating UTF-8 character 42 strings. */ 43 44 45 #ifdef HAVE_CONFIG_H 46 #include "config.h" 47 #endif 48 49 #include "pcre_internal.h" 50 51 52 /************************************************* 53 * Validate a UTF-8 string * 54 *************************************************/ 55 56 /* This function is called (optionally) at the start of compile or match, to 57 check that a supposed UTF-8 string is actually valid. The early check means 58 that subsequent code can assume it is dealing with a valid string. The check 59 can be turned off for maximum performance, but the consequences of supplying an 60 invalid string are then undefined. 61 62 Originally, this function checked according to RFC 2279, allowing for values in 63 the range 0 to 0x7fffffff, up to 6 bytes long, but ensuring that they were in 64 the canonical format. Once somebody had pointed out RFC 3629 to me (it 65 obsoletes 2279), additional restrictions were applied. The values are now 66 limited to be between 0 and 0x0010ffff, no more than 4 bytes long, and the 67 subrange 0xd000 to 0xdfff is excluded. However, the format of 5-byte and 6-byte 68 characters is still checked. 69 70 From release 8.13 more information about the details of the error are passed 71 back in the returned value: 72 73 PCRE_UTF8_ERR0 No error 74 PCRE_UTF8_ERR1 Missing 1 byte at the end of the string 75 PCRE_UTF8_ERR2 Missing 2 bytes at the end of the string 76 PCRE_UTF8_ERR3 Missing 3 bytes at the end of the string 77 PCRE_UTF8_ERR4 Missing 4 bytes at the end of the string 78 PCRE_UTF8_ERR5 Missing 5 bytes at the end of the string 79 PCRE_UTF8_ERR6 2nd-byte's two top bits are not 0x80 80 PCRE_UTF8_ERR7 3rd-byte's two top bits are not 0x80 81 PCRE_UTF8_ERR8 4th-byte's two top bits are not 0x80 82 PCRE_UTF8_ERR9 5th-byte's two top bits are not 0x80 83 PCRE_UTF8_ERR10 6th-byte's two top bits are not 0x80 84 PCRE_UTF8_ERR11 5-byte character is not permitted by RFC 3629 85 PCRE_UTF8_ERR12 6-byte character is not permitted by RFC 3629 86 PCRE_UTF8_ERR13 4-byte character with value > 0x10ffff is not permitted 87 PCRE_UTF8_ERR14 3-byte character with value 0xd000-0xdfff is not permitted 88 PCRE_UTF8_ERR15 Overlong 2-byte sequence 89 PCRE_UTF8_ERR16 Overlong 3-byte sequence 90 PCRE_UTF8_ERR17 Overlong 4-byte sequence 91 PCRE_UTF8_ERR18 Overlong 5-byte sequence (won't ever occur) 92 PCRE_UTF8_ERR19 Overlong 6-byte sequence (won't ever occur) 93 PCRE_UTF8_ERR20 Isolated 0x80 byte (not within UTF-8 character) 94 PCRE_UTF8_ERR21 Byte with the illegal value 0xfe or 0xff 95 PCRE_UTF8_ERR22 Unused (was non-character) 96 97 Arguments: 98 string points to the string 99 length length of string, or -1 if the string is zero-terminated 100 errp pointer to an error position offset variable 101 102 Returns: = 0 if the string is a valid UTF-8 string 103 > 0 otherwise, setting the offset of the bad character 104 */ 105 106 int 107 PRIV(valid_utf)(PCRE_PUCHAR string, int length, int *erroroffset) 108 { 109 #ifdef SUPPORT_UTF 110 register PCRE_PUCHAR p; 111 112 if (length < 0) 113 { 114 for (p = string; *p != 0; p++); 115 length = (int)(p - string); 116 } 117 118 for (p = string; length-- > 0; p++) 119 { 120 register pcre_uchar ab, c, d; 121 122 c = *p; 123 if (c < 128) continue; /* ASCII character */ 124 125 if (c < 0xc0) /* Isolated 10xx xxxx byte */ 126 { 127 *erroroffset = (int)(p - string); 128 return PCRE_UTF8_ERR20; 129 } 130 131 if (c >= 0xfe) /* Invalid 0xfe or 0xff bytes */ 132 { 133 *erroroffset = (int)(p - string); 134 return PCRE_UTF8_ERR21; 135 } 136 137 ab = PRIV(utf8_table4)[c & 0x3f]; /* Number of additional bytes */ 138 if (length < ab) 139 { 140 *erroroffset = (int)(p - string); /* Missing bytes */ 141 return ab - length; /* Codes ERR1 to ERR5 */ 142 } 143 length -= ab; /* Length remaining */ 144 145 /* Check top bits in the second byte */ 146 147 if (((d = *(++p)) & 0xc0) != 0x80) 148 { 149 *erroroffset = (int)(p - string) - 1; 150 return PCRE_UTF8_ERR6; 151 } 152 153 /* For each length, check that the remaining bytes start with the 0x80 bit 154 set and not the 0x40 bit. Then check for an overlong sequence, and for the 155 excluded range 0xd800 to 0xdfff. */ 156 157 switch (ab) 158 { 159 /* 2-byte character. No further bytes to check for 0x80. Check first byte 160 for for xx00 000x (overlong sequence). */ 161 162 case 1: if ((c & 0x3e) == 0) 163 { 164 *erroroffset = (int)(p - string) - 1; 165 return PCRE_UTF8_ERR15; 166 } 167 break; 168 169 /* 3-byte character. Check third byte for 0x80. Then check first 2 bytes 170 for 1110 0000, xx0x xxxx (overlong sequence) or 171 1110 1101, 1010 xxxx (0xd800 - 0xdfff) */ 172 173 case 2: 174 if ((*(++p) & 0xc0) != 0x80) /* Third byte */ 175 { 176 *erroroffset = (int)(p - string) - 2; 177 return PCRE_UTF8_ERR7; 178 } 179 if (c == 0xe0 && (d & 0x20) == 0) 180 { 181 *erroroffset = (int)(p - string) - 2; 182 return PCRE_UTF8_ERR16; 183 } 184 if (c == 0xed && d >= 0xa0) 185 { 186 *erroroffset = (int)(p - string) - 2; 187 return PCRE_UTF8_ERR14; 188 } 189 break; 190 191 /* 4-byte character. Check 3rd and 4th bytes for 0x80. Then check first 2 192 bytes for for 1111 0000, xx00 xxxx (overlong sequence), then check for a 193 character greater than 0x0010ffff (f4 8f bf bf) */ 194 195 case 3: 196 if ((*(++p) & 0xc0) != 0x80) /* Third byte */ 197 { 198 *erroroffset = (int)(p - string) - 2; 199 return PCRE_UTF8_ERR7; 200 } 201 if ((*(++p) & 0xc0) != 0x80) /* Fourth byte */ 202 { 203 *erroroffset = (int)(p - string) - 3; 204 return PCRE_UTF8_ERR8; 205 } 206 if (c == 0xf0 && (d & 0x30) == 0) 207 { 208 *erroroffset = (int)(p - string) - 3; 209 return PCRE_UTF8_ERR17; 210 } 211 if (c > 0xf4 || (c == 0xf4 && d > 0x8f)) 212 { 213 *erroroffset = (int)(p - string) - 3; 214 return PCRE_UTF8_ERR13; 215 } 216 break; 217 218 /* 5-byte and 6-byte characters are not allowed by RFC 3629, and will be 219 rejected by the length test below. However, we do the appropriate tests 220 here so that overlong sequences get diagnosed, and also in case there is 221 ever an option for handling these larger code points. */ 222 223 /* 5-byte character. Check 3rd, 4th, and 5th bytes for 0x80. Then check for 224 1111 1000, xx00 0xxx */ 225 226 case 4: 227 if ((*(++p) & 0xc0) != 0x80) /* Third byte */ 228 { 229 *erroroffset = (int)(p - string) - 2; 230 return PCRE_UTF8_ERR7; 231 } 232 if ((*(++p) & 0xc0) != 0x80) /* Fourth byte */ 233 { 234 *erroroffset = (int)(p - string) - 3; 235 return PCRE_UTF8_ERR8; 236 } 237 if ((*(++p) & 0xc0) != 0x80) /* Fifth byte */ 238 { 239 *erroroffset = (int)(p - string) - 4; 240 return PCRE_UTF8_ERR9; 241 } 242 if (c == 0xf8 && (d & 0x38) == 0) 243 { 244 *erroroffset = (int)(p - string) - 4; 245 return PCRE_UTF8_ERR18; 246 } 247 break; 248 249 /* 6-byte character. Check 3rd-6th bytes for 0x80. Then check for 250 1111 1100, xx00 00xx. */ 251 252 case 5: 253 if ((*(++p) & 0xc0) != 0x80) /* Third byte */ 254 { 255 *erroroffset = (int)(p - string) - 2; 256 return PCRE_UTF8_ERR7; 257 } 258 if ((*(++p) & 0xc0) != 0x80) /* Fourth byte */ 259 { 260 *erroroffset = (int)(p - string) - 3; 261 return PCRE_UTF8_ERR8; 262 } 263 if ((*(++p) & 0xc0) != 0x80) /* Fifth byte */ 264 { 265 *erroroffset = (int)(p - string) - 4; 266 return PCRE_UTF8_ERR9; 267 } 268 if ((*(++p) & 0xc0) != 0x80) /* Sixth byte */ 269 { 270 *erroroffset = (int)(p - string) - 5; 271 return PCRE_UTF8_ERR10; 272 } 273 if (c == 0xfc && (d & 0x3c) == 0) 274 { 275 *erroroffset = (int)(p - string) - 5; 276 return PCRE_UTF8_ERR19; 277 } 278 break; 279 } 280 281 /* Character is valid under RFC 2279, but 4-byte and 5-byte characters are 282 excluded by RFC 3629. The pointer p is currently at the last byte of the 283 character. */ 284 285 if (ab > 3) 286 { 287 *erroroffset = (int)(p - string) - ab; 288 return (ab == 4)? PCRE_UTF8_ERR11 : PCRE_UTF8_ERR12; 289 } 290 } 291 292 #else /* Not SUPPORT_UTF */ 293 (void)(string); /* Keep picky compilers happy */ 294 (void)(length); 295 (void)(erroroffset); 296 #endif 297 298 return PCRE_UTF8_ERR0; /* This indicates success */ 299 } 300 301 /* End of pcre_valid_utf8.c */ 302
