313 lines
10 KiB
C
313 lines
10 KiB
C
/*************************************************
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* Perl-Compatible Regular Expressions *
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*************************************************/
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/* PCRE is a library of functions to support regular expressions whose syntax
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and semantics are as close as possible to those of the Perl 5 language.
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Written by Philip Hazel
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Copyright (c) 1997-2012 University of Cambridge
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-----------------------------------------------------------------------------
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Redistribution and use in source and binary forms, with or without
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modification, are permitted provided that the following conditions are met:
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* Redistributions of source code must retain the above copyright notice,
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this list of conditions and the following disclaimer.
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* Redistributions in binary form must reproduce the above copyright
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notice, this list of conditions and the following disclaimer in the
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documentation and/or other materials provided with the distribution.
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* Neither the name of the University of Cambridge nor the names of its
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contributors may be used to endorse or promote products derived from
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this software without specific prior written permission.
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THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
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AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
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LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
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CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
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SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
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INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
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CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
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ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
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POSSIBILITY OF SUCH DAMAGE.
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-----------------------------------------------------------------------------
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*/
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/* This module contains an internal function for validating UTF-8 character
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strings. */
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#ifdef HAVE_CONFIG_H
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#include "config.h"
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#endif
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#include "pcre_internal.h"
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/*************************************************
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* Validate a UTF-8 string *
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*************************************************/
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/* This function is called (optionally) at the start of compile or match, to
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check that a supposed UTF-8 string is actually valid. The early check means
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that subsequent code can assume it is dealing with a valid string. The check
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can be turned off for maximum performance, but the consequences of supplying an
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invalid string are then undefined.
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Originally, this function checked according to RFC 2279, allowing for values in
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the range 0 to 0x7fffffff, up to 6 bytes long, but ensuring that they were in
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the canonical format. Once somebody had pointed out RFC 3629 to me (it
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obsoletes 2279), additional restrictions were applied. The values are now
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limited to be between 0 and 0x0010ffff, no more than 4 bytes long, and the
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subrange 0xd000 to 0xdfff is excluded. However, the format of 5-byte and 6-byte
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characters is still checked.
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From release 8.13 more information about the details of the error are passed
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back in the returned value:
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PCRE_UTF8_ERR0 No error
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PCRE_UTF8_ERR1 Missing 1 byte at the end of the string
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PCRE_UTF8_ERR2 Missing 2 bytes at the end of the string
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PCRE_UTF8_ERR3 Missing 3 bytes at the end of the string
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PCRE_UTF8_ERR4 Missing 4 bytes at the end of the string
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PCRE_UTF8_ERR5 Missing 5 bytes at the end of the string
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PCRE_UTF8_ERR6 2nd-byte's two top bits are not 0x80
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PCRE_UTF8_ERR7 3rd-byte's two top bits are not 0x80
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PCRE_UTF8_ERR8 4th-byte's two top bits are not 0x80
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PCRE_UTF8_ERR9 5th-byte's two top bits are not 0x80
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PCRE_UTF8_ERR10 6th-byte's two top bits are not 0x80
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PCRE_UTF8_ERR11 5-byte character is not permitted by RFC 3629
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PCRE_UTF8_ERR12 6-byte character is not permitted by RFC 3629
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PCRE_UTF8_ERR13 4-byte character with value > 0x10ffff is not permitted
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PCRE_UTF8_ERR14 3-byte character with value 0xd000-0xdfff is not permitted
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PCRE_UTF8_ERR15 Overlong 2-byte sequence
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PCRE_UTF8_ERR16 Overlong 3-byte sequence
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PCRE_UTF8_ERR17 Overlong 4-byte sequence
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PCRE_UTF8_ERR18 Overlong 5-byte sequence (won't ever occur)
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PCRE_UTF8_ERR19 Overlong 6-byte sequence (won't ever occur)
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PCRE_UTF8_ERR20 Isolated 0x80 byte (not within UTF-8 character)
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PCRE_UTF8_ERR21 Byte with the illegal value 0xfe or 0xff
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PCRE_UTF8_ERR22 Non-character
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Arguments:
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string points to the string
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length length of string, or -1 if the string is zero-terminated
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errp pointer to an error position offset variable
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Returns: = 0 if the string is a valid UTF-8 string
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> 0 otherwise, setting the offset of the bad character
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*/
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int
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PRIV(valid_utf)(PCRE_PUCHAR string, int length, int *erroroffset)
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{
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#ifdef SUPPORT_UTF
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register PCRE_PUCHAR p;
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if (length < 0)
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{
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for (p = string; *p != 0; p++);
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length = (int)(p - string);
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}
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for (p = string; length-- > 0; p++)
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{
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register pcre_uchar ab, c, d;
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pcre_uint32 v = 0;
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c = *p;
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if (c < 128) continue; /* ASCII character */
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if (c < 0xc0) /* Isolated 10xx xxxx byte */
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{
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*erroroffset = (int)(p - string);
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return PCRE_UTF8_ERR20;
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}
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if (c >= 0xfe) /* Invalid 0xfe or 0xff bytes */
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{
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*erroroffset = (int)(p - string);
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return PCRE_UTF8_ERR21;
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}
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ab = PRIV(utf8_table4)[c & 0x3f]; /* Number of additional bytes */
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if (length < ab)
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{
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*erroroffset = (int)(p - string); /* Missing bytes */
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return ab - length; /* Codes ERR1 to ERR5 */
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}
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length -= ab; /* Length remaining */
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/* Check top bits in the second byte */
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if (((d = *(++p)) & 0xc0) != 0x80)
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{
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*erroroffset = (int)(p - string) - 1;
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return PCRE_UTF8_ERR6;
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}
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/* For each length, check that the remaining bytes start with the 0x80 bit
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set and not the 0x40 bit. Then check for an overlong sequence, and for the
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excluded range 0xd800 to 0xdfff. */
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switch (ab)
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{
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/* 2-byte character. No further bytes to check for 0x80. Check first byte
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for for xx00 000x (overlong sequence). */
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case 1: if ((c & 0x3e) == 0)
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{
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*erroroffset = (int)(p - string) - 1;
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return PCRE_UTF8_ERR15;
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}
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break;
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/* 3-byte character. Check third byte for 0x80. Then check first 2 bytes
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for 1110 0000, xx0x xxxx (overlong sequence) or
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1110 1101, 1010 xxxx (0xd800 - 0xdfff) */
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case 2:
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if ((*(++p) & 0xc0) != 0x80) /* Third byte */
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{
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*erroroffset = (int)(p - string) - 2;
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return PCRE_UTF8_ERR7;
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}
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if (c == 0xe0 && (d & 0x20) == 0)
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{
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*erroroffset = (int)(p - string) - 2;
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return PCRE_UTF8_ERR16;
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}
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if (c == 0xed && d >= 0xa0)
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{
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*erroroffset = (int)(p - string) - 2;
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return PCRE_UTF8_ERR14;
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}
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v = ((c & 0x0f) << 12) | ((d & 0x3f) << 6) | (*p & 0x3f);
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break;
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/* 4-byte character. Check 3rd and 4th bytes for 0x80. Then check first 2
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bytes for for 1111 0000, xx00 xxxx (overlong sequence), then check for a
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character greater than 0x0010ffff (f4 8f bf bf) */
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case 3:
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if ((*(++p) & 0xc0) != 0x80) /* Third byte */
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{
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*erroroffset = (int)(p - string) - 2;
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return PCRE_UTF8_ERR7;
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}
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if ((*(++p) & 0xc0) != 0x80) /* Fourth byte */
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{
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*erroroffset = (int)(p - string) - 3;
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return PCRE_UTF8_ERR8;
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}
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if (c == 0xf0 && (d & 0x30) == 0)
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{
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*erroroffset = (int)(p - string) - 3;
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return PCRE_UTF8_ERR17;
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}
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if (c > 0xf4 || (c == 0xf4 && d > 0x8f))
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{
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*erroroffset = (int)(p - string) - 3;
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return PCRE_UTF8_ERR13;
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}
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v = ((c & 0x07) << 18) | ((d & 0x3f) << 12) | ((p[-1] & 0x3f) << 6) | (*p & 0x3f);
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break;
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/* 5-byte and 6-byte characters are not allowed by RFC 3629, and will be
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rejected by the length test below. However, we do the appropriate tests
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here so that overlong sequences get diagnosed, and also in case there is
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ever an option for handling these larger code points. */
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/* 5-byte character. Check 3rd, 4th, and 5th bytes for 0x80. Then check for
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1111 1000, xx00 0xxx */
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case 4:
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if ((*(++p) & 0xc0) != 0x80) /* Third byte */
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{
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*erroroffset = (int)(p - string) - 2;
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return PCRE_UTF8_ERR7;
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}
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if ((*(++p) & 0xc0) != 0x80) /* Fourth byte */
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{
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*erroroffset = (int)(p - string) - 3;
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return PCRE_UTF8_ERR8;
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}
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if ((*(++p) & 0xc0) != 0x80) /* Fifth byte */
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{
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*erroroffset = (int)(p - string) - 4;
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return PCRE_UTF8_ERR9;
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}
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if (c == 0xf8 && (d & 0x38) == 0)
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{
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*erroroffset = (int)(p - string) - 4;
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return PCRE_UTF8_ERR18;
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}
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break;
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/* 6-byte character. Check 3rd-6th bytes for 0x80. Then check for
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1111 1100, xx00 00xx. */
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case 5:
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if ((*(++p) & 0xc0) != 0x80) /* Third byte */
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{
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*erroroffset = (int)(p - string) - 2;
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return PCRE_UTF8_ERR7;
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}
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if ((*(++p) & 0xc0) != 0x80) /* Fourth byte */
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{
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*erroroffset = (int)(p - string) - 3;
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return PCRE_UTF8_ERR8;
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}
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if ((*(++p) & 0xc0) != 0x80) /* Fifth byte */
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{
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*erroroffset = (int)(p - string) - 4;
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return PCRE_UTF8_ERR9;
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}
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if ((*(++p) & 0xc0) != 0x80) /* Sixth byte */
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{
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*erroroffset = (int)(p - string) - 5;
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return PCRE_UTF8_ERR10;
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}
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if (c == 0xfc && (d & 0x3c) == 0)
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{
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*erroroffset = (int)(p - string) - 5;
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return PCRE_UTF8_ERR19;
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}
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break;
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}
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/* Character is valid under RFC 2279, but 4-byte and 5-byte characters are
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excluded by RFC 3629. The pointer p is currently at the last byte of the
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character. */
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if (ab > 3)
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{
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*erroroffset = (int)(p - string) - ab;
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return (ab == 4)? PCRE_UTF8_ERR11 : PCRE_UTF8_ERR12;
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}
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/* Reject non-characters. The pointer p is currently at the last byte of the
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character. */
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if ((v & 0xfffeu) == 0xfffeu || (v >= 0xfdd0 && v <= 0xfdef))
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{
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*erroroffset = (int)(p - string) - ab;
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return PCRE_UTF8_ERR22;
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}
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}
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#else /* Not SUPPORT_UTF */
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(void)(string); /* Keep picky compilers happy */
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(void)(length);
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(void)(erroroffset);
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#endif
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return PCRE_UTF8_ERR0; /* This indicates success */
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}
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/* End of pcre_valid_utf8.c */
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