FS-8160 Additional vulnerability in json parsing malformed utf encoded chars discovered by Brian Martin - Tenable Security Response CVE-2015-7392

This commit is contained in:
Anthony Minessale 2015-11-19 13:45:04 -06:00 committed by Michael Jerris
parent 6d8edab59b
commit 4bdca8197a
3 changed files with 27 additions and 9 deletions

View File

@ -150,6 +150,13 @@ static char *print_number(cJSON *item)
return str;
}
#define is_hexdigit(c) ((c >= '0' && c <= '9') || (c >= 'a' && c <= 'f') || (c >= 'A' && c <= 'F'))
static int scan_unicode(const char *ptr, unsigned int *uc)
{
if (!is_hexdigit(*(ptr)) || !is_hexdigit(*(ptr+1)) || !is_hexdigit(*(ptr+2)) || !is_hexdigit(*(ptr+3))) return -1;
return sscanf(ptr, "%4x", uc);
}
/* Parse the input text into an unescaped cstring, and populate item. */
static const unsigned char firstByteMark[7] = { 0x00, 0x00, 0xC0, 0xE0, 0xF0, 0xF8, 0xFC };
static const char *parse_string(cJSON *item,const char *str)
@ -177,8 +184,7 @@ static const char *parse_string(cJSON *item,const char *str)
case 'r': *ptr2++='\r'; break;
case 't': *ptr2++='\t'; break;
case 'u': /* transcode utf16 to utf8. */
if (sscanf(ptr+1,"%4x",&uc) < 1) break;
if (scan_unicode(ptr+1, &uc) < 1) break;
ptr+=4; /* get the unicode char. */
if ((uc>=0xDC00 && uc<=0xDFFF) || uc==0) break; // check for invalid.
@ -186,7 +192,7 @@ static const char *parse_string(cJSON *item,const char *str)
if (uc>=0xD800 && uc<=0xDBFF) // UTF16 surrogate pairs.
{
if (ptr[1]!='\\' || ptr[2]!='u') break; // missing second-half of surrogate.
if (sscanf(ptr+3,"%4x",&uc2) < 1) break;
if (scan_unicode(ptr+3,&uc2) < 1) break;
ptr+=6;
if (uc2<0xDC00 || uc2>0xDFFF) break; // invalid second-half of surrogate.
uc=0x10000 | ((uc&0x3FF)<<10) | (uc2&0x3FF);

View File

@ -150,6 +150,13 @@ static char *print_number(cJSON *item)
return str;
}
#define is_hexdigit(c) ((c >= '0' && c <= '9') || (c >= 'a' && c <= 'f') || (c >= 'A' && c <= 'F'))
static int scan_unicode(const char *ptr, unsigned int *uc)
{
if (!is_hexdigit(*(ptr)) || !is_hexdigit(*(ptr+1)) || !is_hexdigit(*(ptr+2)) || !is_hexdigit(*(ptr+3))) return -1;
return sscanf(ptr, "%4x", uc);
}
/* Parse the input text into an unescaped cstring, and populate item. */
static const unsigned char firstByteMark[7] = { 0x00, 0x00, 0xC0, 0xE0, 0xF0, 0xF8, 0xFC };
static const char *parse_string(cJSON *item,const char *str)
@ -177,8 +184,7 @@ static const char *parse_string(cJSON *item,const char *str)
case 'r': *ptr2++='\r'; break;
case 't': *ptr2++='\t'; break;
case 'u': /* transcode utf16 to utf8. */
if (sscanf(ptr+1,"%4x",&uc) < 1) break;
if (scan_unicode(ptr+1, &uc) < 1) break;
ptr+=4; /* get the unicode char. */
if ((uc>=0xDC00 && uc<=0xDFFF) || uc==0) break; // check for invalid.
@ -186,7 +192,7 @@ static const char *parse_string(cJSON *item,const char *str)
if (uc>=0xD800 && uc<=0xDBFF) // UTF16 surrogate pairs.
{
if (ptr[1]!='\\' || ptr[2]!='u') break; // missing second-half of surrogate.
if (sscanf(ptr+3,"%4x",&uc2) < 1) break;
if (scan_unicode(ptr+3,&uc2) < 1) break;
ptr+=6;
if (uc2<0xDC00 || uc2>0xDFFF) break; // invalid second-half of surrogate.
uc=0x10000 | ((uc&0x3FF)<<10) | (uc2&0x3FF);

View File

@ -150,6 +150,13 @@ static char *print_number(cJSON *item)
return str;
}
#define is_hexdigit(c) ((c >= '0' && c <= '9') || (c >= 'a' && c <= 'f') || (c >= 'A' && c <= 'F'))
static int scan_unicode(const char *ptr, unsigned int *uc)
{
if (!is_hexdigit(*(ptr)) || !is_hexdigit(*(ptr+1)) || !is_hexdigit(*(ptr+2)) || !is_hexdigit(*(ptr+3))) return -1;
return sscanf(ptr, "%4x", uc);
}
/* Parse the input text into an unescaped cstring, and populate item. */
static const unsigned char firstByteMark[7] = { 0x00, 0x00, 0xC0, 0xE0, 0xF0, 0xF8, 0xFC };
static const char *parse_string(cJSON *item,const char *str)
@ -177,8 +184,7 @@ static const char *parse_string(cJSON *item,const char *str)
case 'r': *ptr2++='\r'; break;
case 't': *ptr2++='\t'; break;
case 'u': /* transcode utf16 to utf8. */
if (sscanf(ptr+1,"%4x",&uc) < 1) break;
if (scan_unicode(ptr+1, &uc) < 1) break;
ptr+=4; /* get the unicode char. */
if ((uc>=0xDC00 && uc<=0xDFFF) || uc==0) break; // check for invalid.
@ -186,7 +192,7 @@ static const char *parse_string(cJSON *item,const char *str)
if (uc>=0xD800 && uc<=0xDBFF) // UTF16 surrogate pairs.
{
if (ptr[1]!='\\' || ptr[2]!='u') break; // missing second-half of surrogate.
if (sscanf(ptr+3,"%4x",&uc2) < 1) break;
if (scan_unicode(ptr+3,&uc2) < 1) break;
ptr+=6;
if (uc2<0xDC00 || uc2>0xDFFF) break; // invalid second-half of surrogate.
uc=0x10000 | ((uc&0x3FF)<<10) | (uc2&0x3FF);