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libxml2/xmlstring.c
Nick Wellnhofer c7260a47f1 malloc-fail: Don't call xmlErrMemory in xmlstring.c 
Functions like xmlStrdup are called in the error handling code
(__xmlRaiseError) which can cause problems like use-after-free or
infinite loops when invoked recursively.

Calling xmlErrMemory without a context argument isn't helpful anyway.

Found with libFuzzer, see #344.
2023-01-24 11:47:33 +01:00

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/*
* string.c : an XML string utilities module
*
* This module provides various utility functions for manipulating
* the xmlChar* type. All functions named xmlStr* have been moved here
* from the parser.c file (their original home).
*
* See Copyright for the status of this software.
*
* UTF8 string routines from:
* William Brack <wbrack@mmm.com.hk>
*
* daniel@veillard.com
*/
#define IN_LIBXML
#include "libxml.h"
#include <stdlib.h>
#include <string.h>
#include <limits.h>
#include <libxml/xmlmemory.h>
#include <libxml/parserInternals.h>
#include <libxml/xmlstring.h>
#include "private/parser.h"
#include "private/string.h"
/************************************************************************
* *
* Commodity functions to handle xmlChars *
* *
************************************************************************/
/**
* xmlStrndup:
* @cur: the input xmlChar *
* @len: the len of @cur
*
* a strndup for array of xmlChar's
*
* Returns a new xmlChar * or NULL
*/
xmlChar *
xmlStrndup(const xmlChar *cur, int len) {
xmlChar *ret;
if ((cur == NULL) || (len < 0)) return(NULL);
ret = (xmlChar *) xmlMallocAtomic((size_t) len + 1);
if (ret == NULL) {
return(NULL);
}
memcpy(ret, cur, len);
ret[len] = 0;
return(ret);
}
/**
* xmlStrdup:
* @cur: the input xmlChar *
*
* a strdup for array of xmlChar's. Since they are supposed to be
* encoded in UTF-8 or an encoding with 8bit based chars, we assume
* a termination mark of '0'.
*
* Returns a new xmlChar * or NULL
*/
xmlChar *
xmlStrdup(const xmlChar *cur) {
const xmlChar *p = cur;
if (cur == NULL) return(NULL);
while (*p != 0) p++; /* non input consuming */
return(xmlStrndup(cur, p - cur));
}
/**
* xmlCharStrndup:
* @cur: the input char *
* @len: the len of @cur
*
* a strndup for char's to xmlChar's
*
* Returns a new xmlChar * or NULL
*/
xmlChar *
xmlCharStrndup(const char *cur, int len) {
int i;
xmlChar *ret;
if ((cur == NULL) || (len < 0)) return(NULL);
ret = (xmlChar *) xmlMallocAtomic((size_t) len + 1);
if (ret == NULL) {
return(NULL);
}
for (i = 0;i < len;i++) {
/* Explicit sign change */
ret[i] = (xmlChar) cur[i];
if (ret[i] == 0) return(ret);
}
ret[len] = 0;
return(ret);
}
/**
* xmlCharStrdup:
* @cur: the input char *
*
* a strdup for char's to xmlChar's
*
* Returns a new xmlChar * or NULL
*/
xmlChar *
xmlCharStrdup(const char *cur) {
const char *p = cur;
if (cur == NULL) return(NULL);
while (*p != '\0') p++; /* non input consuming */
return(xmlCharStrndup(cur, p - cur));
}
/**
* xmlStrcmp:
* @str1: the first xmlChar *
* @str2: the second xmlChar *
*
* a strcmp for xmlChar's
*
* Returns the integer result of the comparison
*/
int
xmlStrcmp(const xmlChar *str1, const xmlChar *str2) {
if (str1 == str2) return(0);
if (str1 == NULL) return(-1);
if (str2 == NULL) return(1);
#ifdef FUZZING_BUILD_MODE_UNSAFE_FOR_PRODUCTION
return(strcmp((const char *)str1, (const char *)str2));
#else
do {
int tmp = *str1++ - *str2;
if (tmp != 0) return(tmp);
} while (*str2++ != 0);
return 0;
#endif
}
/**
* xmlStrEqual:
* @str1: the first xmlChar *
* @str2: the second xmlChar *
*
* Check if both strings are equal of have same content.
* Should be a bit more readable and faster than xmlStrcmp()
*
* Returns 1 if they are equal, 0 if they are different
*/
int
xmlStrEqual(const xmlChar *str1, const xmlChar *str2) {
if (str1 == str2) return(1);
if (str1 == NULL) return(0);
if (str2 == NULL) return(0);
#ifdef FUZZING_BUILD_MODE_UNSAFE_FOR_PRODUCTION
return(strcmp((const char *)str1, (const char *)str2) == 0);
#else
do {
if (*str1++ != *str2) return(0);
} while (*str2++);
return(1);
#endif
}
/**
* xmlStrQEqual:
* @pref: the prefix of the QName
* @name: the localname of the QName
* @str: the second xmlChar *
*
* Check if a QName is Equal to a given string
*
* Returns 1 if they are equal, 0 if they are different
*/
int
xmlStrQEqual(const xmlChar *pref, const xmlChar *name, const xmlChar *str) {
if (pref == NULL) return(xmlStrEqual(name, str));
if (name == NULL) return(0);
if (str == NULL) return(0);
do {
if (*pref++ != *str) return(0);
} while ((*str++) && (*pref));
if (*str++ != ':') return(0);
do {
if (*name++ != *str) return(0);
} while (*str++);
return(1);
}
/**
* xmlStrncmp:
* @str1: the first xmlChar *
* @str2: the second xmlChar *
* @len: the max comparison length
*
* a strncmp for xmlChar's
*
* Returns the integer result of the comparison
*/
int
xmlStrncmp(const xmlChar *str1, const xmlChar *str2, int len) {
if (len <= 0) return(0);
if (str1 == str2) return(0);
if (str1 == NULL) return(-1);
if (str2 == NULL) return(1);
#ifdef FUZZING_BUILD_MODE_UNSAFE_FOR_PRODUCTION
return(strncmp((const char *)str1, (const char *)str2, len));
#else
do {
int tmp = *str1++ - *str2;
if (tmp != 0 || --len == 0) return(tmp);
} while (*str2++ != 0);
return 0;
#endif
}
static const xmlChar casemap[256] = {
0x00,0x01,0x02,0x03,0x04,0x05,0x06,0x07,
0x08,0x09,0x0A,0x0B,0x0C,0x0D,0x0E,0x0F,
0x10,0x11,0x12,0x13,0x14,0x15,0x16,0x17,
0x18,0x19,0x1A,0x1B,0x1C,0x1D,0x1E,0x1F,
0x20,0x21,0x22,0x23,0x24,0x25,0x26,0x27,
0x28,0x29,0x2A,0x2B,0x2C,0x2D,0x2E,0x2F,
0x30,0x31,0x32,0x33,0x34,0x35,0x36,0x37,
0x38,0x39,0x3A,0x3B,0x3C,0x3D,0x3E,0x3F,
0x40,0x61,0x62,0x63,0x64,0x65,0x66,0x67,
0x68,0x69,0x6A,0x6B,0x6C,0x6D,0x6E,0x6F,
0x70,0x71,0x72,0x73,0x74,0x75,0x76,0x77,
0x78,0x79,0x7A,0x7B,0x5C,0x5D,0x5E,0x5F,
0x60,0x61,0x62,0x63,0x64,0x65,0x66,0x67,
0x68,0x69,0x6A,0x6B,0x6C,0x6D,0x6E,0x6F,
0x70,0x71,0x72,0x73,0x74,0x75,0x76,0x77,
0x78,0x79,0x7A,0x7B,0x7C,0x7D,0x7E,0x7F,
0x80,0x81,0x82,0x83,0x84,0x85,0x86,0x87,
0x88,0x89,0x8A,0x8B,0x8C,0x8D,0x8E,0x8F,
0x90,0x91,0x92,0x93,0x94,0x95,0x96,0x97,
0x98,0x99,0x9A,0x9B,0x9C,0x9D,0x9E,0x9F,
0xA0,0xA1,0xA2,0xA3,0xA4,0xA5,0xA6,0xA7,
0xA8,0xA9,0xAA,0xAB,0xAC,0xAD,0xAE,0xAF,
0xB0,0xB1,0xB2,0xB3,0xB4,0xB5,0xB6,0xB7,
0xB8,0xB9,0xBA,0xBB,0xBC,0xBD,0xBE,0xBF,
0xC0,0xC1,0xC2,0xC3,0xC4,0xC5,0xC6,0xC7,
0xC8,0xC9,0xCA,0xCB,0xCC,0xCD,0xCE,0xCF,
0xD0,0xD1,0xD2,0xD3,0xD4,0xD5,0xD6,0xD7,
0xD8,0xD9,0xDA,0xDB,0xDC,0xDD,0xDE,0xDF,
0xE0,0xE1,0xE2,0xE3,0xE4,0xE5,0xE6,0xE7,
0xE8,0xE9,0xEA,0xEB,0xEC,0xED,0xEE,0xEF,
0xF0,0xF1,0xF2,0xF3,0xF4,0xF5,0xF6,0xF7,
0xF8,0xF9,0xFA,0xFB,0xFC,0xFD,0xFE,0xFF
};
/**
* xmlStrcasecmp:
* @str1: the first xmlChar *
* @str2: the second xmlChar *
*
* a strcasecmp for xmlChar's
*
* Returns the integer result of the comparison
*/
int
xmlStrcasecmp(const xmlChar *str1, const xmlChar *str2) {
register int tmp;
if (str1 == str2) return(0);
if (str1 == NULL) return(-1);
if (str2 == NULL) return(1);
do {
tmp = casemap[*str1++] - casemap[*str2];
if (tmp != 0) return(tmp);
} while (*str2++ != 0);
return 0;
}
/**
* xmlStrncasecmp:
* @str1: the first xmlChar *
* @str2: the second xmlChar *
* @len: the max comparison length
*
* a strncasecmp for xmlChar's
*
* Returns the integer result of the comparison
*/
int
xmlStrncasecmp(const xmlChar *str1, const xmlChar *str2, int len) {
register int tmp;
if (len <= 0) return(0);
if (str1 == str2) return(0);
if (str1 == NULL) return(-1);
if (str2 == NULL) return(1);
do {
tmp = casemap[*str1++] - casemap[*str2];
if (tmp != 0 || --len == 0) return(tmp);
} while (*str2++ != 0);
return 0;
}
/**
* xmlStrchr:
* @str: the xmlChar * array
* @val: the xmlChar to search
*
* a strchr for xmlChar's
*
* Returns the xmlChar * for the first occurrence or NULL.
*/
const xmlChar *
xmlStrchr(const xmlChar *str, xmlChar val) {
if (str == NULL) return(NULL);
while (*str != 0) { /* non input consuming */
if (*str == val) return((xmlChar *) str);
str++;
}
return(NULL);
}
/**
* xmlStrstr:
* @str: the xmlChar * array (haystack)
* @val: the xmlChar to search (needle)
*
* a strstr for xmlChar's
*
* Returns the xmlChar * for the first occurrence or NULL.
*/
const xmlChar *
xmlStrstr(const xmlChar *str, const xmlChar *val) {
int n;
if (str == NULL) return(NULL);
if (val == NULL) return(NULL);
n = xmlStrlen(val);
if (n == 0) return(str);
while (*str != 0) { /* non input consuming */
if (*str == *val) {
if (!xmlStrncmp(str, val, n)) return((const xmlChar *) str);
}
str++;
}
return(NULL);
}
/**
* xmlStrcasestr:
* @str: the xmlChar * array (haystack)
* @val: the xmlChar to search (needle)
*
* a case-ignoring strstr for xmlChar's
*
* Returns the xmlChar * for the first occurrence or NULL.
*/
const xmlChar *
xmlStrcasestr(const xmlChar *str, const xmlChar *val) {
int n;
if (str == NULL) return(NULL);
if (val == NULL) return(NULL);
n = xmlStrlen(val);
if (n == 0) return(str);
while (*str != 0) { /* non input consuming */
if (casemap[*str] == casemap[*val])
if (!xmlStrncasecmp(str, val, n)) return(str);
str++;
}
return(NULL);
}
/**
* xmlStrsub:
* @str: the xmlChar * array (haystack)
* @start: the index of the first char (zero based)
* @len: the length of the substring
*
* Extract a substring of a given string
*
* Returns the xmlChar * for the first occurrence or NULL.
*/
xmlChar *
xmlStrsub(const xmlChar *str, int start, int len) {
int i;
if (str == NULL) return(NULL);
if (start < 0) return(NULL);
if (len < 0) return(NULL);
for (i = 0;i < start;i++) {
if (*str == 0) return(NULL);
str++;
}
if (*str == 0) return(NULL);
return(xmlStrndup(str, len));
}
/**
* xmlStrlen:
* @str: the xmlChar * array
*
* length of a xmlChar's string
*
* Returns the number of xmlChar contained in the ARRAY.
*/
int
xmlStrlen(const xmlChar *str) {
size_t len = str ? strlen((const char *)str) : 0;
return(len > INT_MAX ? 0 : len);
}
/**
* xmlStrncat:
* @cur: the original xmlChar * array
* @add: the xmlChar * array added
* @len: the length of @add
*
* a strncat for array of xmlChar's, it will extend @cur with the len
* first bytes of @add. Note that if @len < 0 then this is an API error
* and NULL will be returned.
*
* Returns a new xmlChar *, the original @cur is reallocated and should
* not be freed.
*/
xmlChar *
xmlStrncat(xmlChar *cur, const xmlChar *add, int len) {
int size;
xmlChar *ret;
if ((add == NULL) || (len == 0))
return(cur);
if (len < 0)
return(NULL);
if (cur == NULL)
return(xmlStrndup(add, len));
size = xmlStrlen(cur);
if ((size < 0) || (size > INT_MAX - len))
return(NULL);
ret = (xmlChar *) xmlRealloc(cur, (size_t) size + len + 1);
if (ret == NULL) {
return(cur);
}
memcpy(&ret[size], add, len);
ret[size + len] = 0;
return(ret);
}
/**
* xmlStrncatNew:
* @str1: first xmlChar string
* @str2: second xmlChar string
* @len: the len of @str2 or < 0
*
* same as xmlStrncat, but creates a new string. The original
* two strings are not freed. If @len is < 0 then the length
* will be calculated automatically.
*
* Returns a new xmlChar * or NULL
*/
xmlChar *
xmlStrncatNew(const xmlChar *str1, const xmlChar *str2, int len) {
int size;
xmlChar *ret;
if (len < 0) {
len = xmlStrlen(str2);
if (len < 0)
return(NULL);
}
if ((str2 == NULL) || (len == 0))
return(xmlStrdup(str1));
if (str1 == NULL)
return(xmlStrndup(str2, len));
size = xmlStrlen(str1);
if ((size < 0) || (size > INT_MAX - len))
return(NULL);
ret = (xmlChar *) xmlMalloc((size_t) size + len + 1);
if (ret == NULL) {
return(xmlStrndup(str1, size));
}
memcpy(ret, str1, size);
memcpy(&ret[size], str2, len);
ret[size + len] = 0;
return(ret);
}
/**
* xmlStrcat:
* @cur: the original xmlChar * array
* @add: the xmlChar * array added
*
* a strcat for array of xmlChar's. Since they are supposed to be
* encoded in UTF-8 or an encoding with 8bit based chars, we assume
* a termination mark of '0'.
*
* Returns a new xmlChar * containing the concatenated string. The original
* @cur is reallocated and should not be freed.
*/
xmlChar *
xmlStrcat(xmlChar *cur, const xmlChar *add) {
const xmlChar *p = add;
if (add == NULL) return(cur);
if (cur == NULL)
return(xmlStrdup(add));
while (*p != 0) p++; /* non input consuming */
return(xmlStrncat(cur, add, p - add));
}
/**
* xmlStrPrintf:
* @buf: the result buffer.
* @len: the result buffer length.
* @msg: the message with printf formatting.
* @...: extra parameters for the message.
*
* Formats @msg and places result into @buf.
*
* Returns the number of characters written to @buf or -1 if an error occurs.
*/
int
xmlStrPrintf(xmlChar *buf, int len, const char *msg, ...) {
va_list args;
int ret;
if((buf == NULL) || (msg == NULL)) {
return(-1);
}
va_start(args, msg);
ret = vsnprintf((char *) buf, len, (const char *) msg, args);
va_end(args);
buf[len - 1] = 0; /* be safe ! */
return(ret);
}
/**
* xmlStrVPrintf:
* @buf: the result buffer.
* @len: the result buffer length.
* @msg: the message with printf formatting.
* @ap: extra parameters for the message.
*
* Formats @msg and places result into @buf.
*
* Returns the number of characters written to @buf or -1 if an error occurs.
*/
int
xmlStrVPrintf(xmlChar *buf, int len, const char *msg, va_list ap) {
int ret;
if((buf == NULL) || (msg == NULL)) {
return(-1);
}
ret = vsnprintf((char *) buf, len, (const char *) msg, ap);
buf[len - 1] = 0; /* be safe ! */
return(ret);
}
/************************************************************************
* *
* Generic UTF8 handling routines *
* *
* From rfc2044: encoding of the Unicode values on UTF-8: *
* *
* UCS-4 range (hex.) UTF-8 octet sequence (binary) *
* 0000 0000-0000 007F 0xxxxxxx *
* 0000 0080-0000 07FF 110xxxxx 10xxxxxx *
* 0000 0800-0000 FFFF 1110xxxx 10xxxxxx 10xxxxxx *
* *
* I hope we won't use values > 0xFFFF anytime soon ! *
* *
************************************************************************/
/**
* xmlUTF8Size:
* @utf: pointer to the UTF8 character
*
* calculates the internal size of a UTF8 character
*
* returns the numbers of bytes in the character, -1 on format error
*/
int
xmlUTF8Size(const xmlChar *utf) {
xmlChar mask;
int len;
if (utf == NULL)
return -1;
if (*utf < 0x80)
return 1;
/* check valid UTF8 character */
if (!(*utf & 0x40))
return -1;
/* determine number of bytes in char */
len = 2;
for (mask=0x20; mask != 0; mask>>=1) {
if (!(*utf & mask))
return len;
len++;
}
return -1;
}
/**
* xmlUTF8Charcmp:
* @utf1: pointer to first UTF8 char
* @utf2: pointer to second UTF8 char
*
* compares the two UCS4 values
*
* returns result of the compare as with xmlStrncmp
*/
int
xmlUTF8Charcmp(const xmlChar *utf1, const xmlChar *utf2) {
if (utf1 == NULL ) {
if (utf2 == NULL)
return 0;
return -1;
}
return xmlStrncmp(utf1, utf2, xmlUTF8Size(utf1));
}
/**
* xmlUTF8Strlen:
* @utf: a sequence of UTF-8 encoded bytes
*
* compute the length of an UTF8 string, it doesn't do a full UTF8
* checking of the content of the string.
*
* Returns the number of characters in the string or -1 in case of error
*/
int
xmlUTF8Strlen(const xmlChar *utf) {
size_t ret = 0;
if (utf == NULL)
return(-1);
while (*utf != 0) {
if (utf[0] & 0x80) {
if ((utf[1] & 0xc0) != 0x80)
return(-1);
if ((utf[0] & 0xe0) == 0xe0) {
if ((utf[2] & 0xc0) != 0x80)
return(-1);
if ((utf[0] & 0xf0) == 0xf0) {
if ((utf[0] & 0xf8) != 0xf0 || (utf[3] & 0xc0) != 0x80)
return(-1);
utf += 4;
} else {
utf += 3;
}
} else {
utf += 2;
}
} else {
utf++;
}
ret++;
}
return(ret > INT_MAX ? 0 : ret);
}
/**
* xmlGetUTF8Char:
* @utf: a sequence of UTF-8 encoded bytes
* @len: a pointer to the minimum number of bytes present in
* the sequence. This is used to assure the next character
* is completely contained within the sequence.
*
* Read the first UTF8 character from @utf
*
* Returns the char value or -1 in case of error, and sets *len to
* the actual number of bytes consumed (0 in case of error)
*/
int
xmlGetUTF8Char(const unsigned char *utf, int *len) {
unsigned int c;
if (utf == NULL)
goto error;
if (len == NULL)
goto error;
if (*len < 1)
goto error;
c = utf[0];
if (c & 0x80) {
if (*len < 2)
goto error;
if ((utf[1] & 0xc0) != 0x80)
goto error;
if ((c & 0xe0) == 0xe0) {
if (*len < 3)
goto error;
if ((utf[2] & 0xc0) != 0x80)
goto error;
if ((c & 0xf0) == 0xf0) {
if (*len < 4)
goto error;
if ((c & 0xf8) != 0xf0 || (utf[3] & 0xc0) != 0x80)
goto error;
*len = 4;
/* 4-byte code */
c = (utf[0] & 0x7) << 18;
c |= (utf[1] & 0x3f) << 12;
c |= (utf[2] & 0x3f) << 6;
c |= utf[3] & 0x3f;
} else {
/* 3-byte code */
*len = 3;
c = (utf[0] & 0xf) << 12;
c |= (utf[1] & 0x3f) << 6;
c |= utf[2] & 0x3f;
}
} else {
/* 2-byte code */
*len = 2;
c = (utf[0] & 0x1f) << 6;
c |= utf[1] & 0x3f;
}
} else {
/* 1-byte code */
*len = 1;
}
return(c);
error:
if (len != NULL)
*len = 0;
return(-1);
}
/**
* xmlCheckUTF8:
* @utf: Pointer to putative UTF-8 encoded string.
*
* Checks @utf for being valid UTF-8. @utf is assumed to be
* null-terminated. This function is not super-strict, as it will
* allow longer UTF-8 sequences than necessary. Note that Java is
* capable of producing these sequences if provoked. Also note, this
* routine checks for the 4-byte maximum size, but does not check for
* 0x10ffff maximum value.
*
* Return value: true if @utf is valid.
**/
int
xmlCheckUTF8(const unsigned char *utf)
{
int ix;
unsigned char c;
if (utf == NULL)
return(0);
/*
* utf is a string of 1, 2, 3 or 4 bytes. The valid strings
* are as follows (in "bit format"):
* 0xxxxxxx valid 1-byte
* 110xxxxx 10xxxxxx valid 2-byte
* 1110xxxx 10xxxxxx 10xxxxxx valid 3-byte
* 11110xxx 10xxxxxx 10xxxxxx 10xxxxxx valid 4-byte
*/
while ((c = utf[0])) { /* string is 0-terminated */
ix = 0;
if ((c & 0x80) == 0x00) { /* 1-byte code, starts with 10 */
ix = 1;
} else if ((c & 0xe0) == 0xc0) {/* 2-byte code, starts with 110 */
if ((utf[1] & 0xc0 ) != 0x80)
return 0;
ix = 2;
} else if ((c & 0xf0) == 0xe0) {/* 3-byte code, starts with 1110 */
if (((utf[1] & 0xc0) != 0x80) ||
((utf[2] & 0xc0) != 0x80))
return 0;
ix = 3;
} else if ((c & 0xf8) == 0xf0) {/* 4-byte code, starts with 11110 */
if (((utf[1] & 0xc0) != 0x80) ||
((utf[2] & 0xc0) != 0x80) ||
((utf[3] & 0xc0) != 0x80))
return 0;
ix = 4;
} else /* unknown encoding */
return 0;
utf += ix;
}
return(1);
}
/**
* xmlUTF8Strsize:
* @utf: a sequence of UTF-8 encoded bytes
* @len: the number of characters in the array
*
* storage size of an UTF8 string
* the behaviour is not guaranteed if the input string is not UTF-8
*
* Returns the storage size of
* the first 'len' characters of ARRAY
*/
int
xmlUTF8Strsize(const xmlChar *utf, int len) {
const xmlChar *ptr=utf;
int ch;
size_t ret;
if (utf == NULL)
return(0);
if (len <= 0)
return(0);
while ( len-- > 0) {
if ( !*ptr )
break;
if ( (ch = *ptr++) & 0x80)
while ((ch<<=1) & 0x80 ) {
if (*ptr == 0) break;
ptr++;
}
}
ret = ptr - utf;
return (ret > INT_MAX ? 0 : ret);
}
/**
* xmlUTF8Strndup:
* @utf: the input UTF8 *
* @len: the len of @utf (in chars)
*
* a strndup for array of UTF8's
*
* Returns a new UTF8 * or NULL
*/
xmlChar *
xmlUTF8Strndup(const xmlChar *utf, int len) {
xmlChar *ret;
int i;
if ((utf == NULL) || (len < 0)) return(NULL);
i = xmlUTF8Strsize(utf, len);
ret = (xmlChar *) xmlMallocAtomic((size_t) i + 1);
if (ret == NULL) {
return(NULL);
}
memcpy(ret, utf, i);
ret[i] = 0;
return(ret);
}
/**
* xmlUTF8Strpos:
* @utf: the input UTF8 *
* @pos: the position of the desired UTF8 char (in chars)
*
* a function to provide the equivalent of fetching a
* character from a string array
*
* Returns a pointer to the UTF8 character or NULL
*/
const xmlChar *
xmlUTF8Strpos(const xmlChar *utf, int pos) {
int ch;
if (utf == NULL) return(NULL);
if (pos < 0)
return(NULL);
while (pos--) {
if ((ch=*utf++) == 0) return(NULL);
if ( ch & 0x80 ) {
/* if not simple ascii, verify proper format */
if ( (ch & 0xc0) != 0xc0 )
return(NULL);
/* then skip over remaining bytes for this char */
while ( (ch <<= 1) & 0x80 )
if ( (*utf++ & 0xc0) != 0x80 )
return(NULL);
}
}
return((xmlChar *)utf);
}
/**
* xmlUTF8Strloc:
* @utf: the input UTF8 *
* @utfchar: the UTF8 character to be found
*
* a function to provide the relative location of a UTF8 char
*
* Returns the relative character position of the desired char
* or -1 if not found
*/
int
xmlUTF8Strloc(const xmlChar *utf, const xmlChar *utfchar) {
size_t i;
int size;
int ch;
if (utf==NULL || utfchar==NULL) return -1;
size = xmlUTF8Strsize(utfchar, 1);
for(i=0; (ch=*utf) != 0; i++) {
if (xmlStrncmp(utf, utfchar, size)==0)
return(i > INT_MAX ? 0 : i);
utf++;
if ( ch & 0x80 ) {
/* if not simple ascii, verify proper format */
if ( (ch & 0xc0) != 0xc0 )
return(-1);
/* then skip over remaining bytes for this char */
while ( (ch <<= 1) & 0x80 )
if ( (*utf++ & 0xc0) != 0x80 )
return(-1);
}
}
return(-1);
}
/**
* xmlUTF8Strsub:
* @utf: a sequence of UTF-8 encoded bytes
* @start: relative pos of first char
* @len: total number to copy
*
* Create a substring from a given UTF-8 string
* Note: positions are given in units of UTF-8 chars
*
* Returns a pointer to a newly created string
* or NULL if any problem
*/
xmlChar *
xmlUTF8Strsub(const xmlChar *utf, int start, int len) {
int i;
int ch;
if (utf == NULL) return(NULL);
if (start < 0) return(NULL);
if (len < 0) return(NULL);
/*
* Skip over any leading chars
*/
for (i = 0;i < start;i++) {
if ((ch=*utf++) == 0) return(NULL);
if ( ch & 0x80 ) {
/* if not simple ascii, verify proper format */
if ( (ch & 0xc0) != 0xc0 )
return(NULL);
/* then skip over remaining bytes for this char */
while ( (ch <<= 1) & 0x80 )
if ( (*utf++ & 0xc0) != 0x80 )
return(NULL);
}
}
return(xmlUTF8Strndup(utf, len));
}
/**
* xmlEscapeFormatString:
* @msg: a pointer to the string in which to escape '%' characters.
* Must be a heap-allocated buffer created by libxml2 that may be
* returned, or that may be freed and replaced.
*
* Replaces the string pointed to by 'msg' with an escaped string.
* Returns the same string with all '%' characters escaped.
*/
xmlChar *
xmlEscapeFormatString(xmlChar **msg)
{
xmlChar *msgPtr = NULL;
xmlChar *result = NULL;
xmlChar *resultPtr = NULL;
size_t count = 0;
size_t msgLen = 0;
size_t resultLen = 0;
if (!msg || !*msg)
return(NULL);
for (msgPtr = *msg; *msgPtr != '\0'; ++msgPtr) {
++msgLen;
if (*msgPtr == '%')
++count;
}
if (count == 0)
return(*msg);
if ((count > INT_MAX) || (msgLen > INT_MAX - count))
return(NULL);
resultLen = msgLen + count + 1;
result = (xmlChar *) xmlMallocAtomic(resultLen);
if (result == NULL) {
/* Clear *msg to prevent format string vulnerabilities in
out-of-memory situations. */
xmlFree(*msg);
*msg = NULL;
return(NULL);
}
for (msgPtr = *msg, resultPtr = result; *msgPtr != '\0'; ++msgPtr, ++resultPtr) {
*resultPtr = *msgPtr;
if (*msgPtr == '%')
*(++resultPtr) = '%';
}
result[resultLen - 1] = '\0';
xmlFree(*msg);
*msg = result;
return *msg;
}
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