[PHP-DEV] Bug #3062: dechex doesn't handle negative numbers From: anderson <email protected>
Date: 12/28/99

From: anderson <email protected>
Operating system: FreeBSD
PHP version: 3.0.12
PHP Bug Type: Misbehaving function
Bug description: dechex doesn't handle negative numbers

The function dechex() can be passed a negative number, which will
create a negative index into a static array. This was discoverd when trying to manipulate IP addresses represented by integers. Any IP that has a first octet >127 will cause this to happen. Since integers are signed, I wonder what other areas might have a similar problem when trying to manipulate IP addresses in this way.

Simple Example:

print(dechex(-333333));

This fix seems to correct this instance of the problem, but I fear that there could possibly be undesirable side effect of doing this.

*** php-3.0.12/functions/math.c Thu Apr 22 09:19:50 1999
--- php/functions/math.c Tue Dec 28 21:16:08 1999
***************
*** 424,430 ****
        static char digits[] = "0123456789abcdefghijklmnopqrstuvwxyz";
        char *result, *ptr, *ret;
        int len, digit;
! long value;
  
        if (arg->type != IS_LONG || base < 2 || base > 36) {
                return empty_string;
--- 424,430 ----
        static char digits[] = "0123456789abcdefghijklmnopqrstuvwxyz";
        char *result, *ptr, *ret;
        int len, digit;
! unsigned long value;
  
        if (arg->type != IS_LONG || base < 2 || base > 36) {
                return empty_string; 

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