Comment 2 for bug 1048203

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In , Jsm28 (jsm28) wrote :

The code in string/strcoll_l.c that computes a memory allocation size as (s1len + s2len) * (sizeof (int32_t) + 1) fails to allow for possible integer overflow in this computation. On a 32-bit host this can cause too-small allocations and consequent buffer overflow if the strings total more than 0.8GB. Testcase:

#include <locale.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>

#define SIZE 429496730

int
main (void)
{
  char *p = malloc (1 + SIZE);
  if (setlocale (LC_COLLATE, "en_GB.UTF-8") == NULL)
    {
      puts ("setlocale failed, cannot test for overflow");
      return 0;
    }
  if (p == NULL)
    {
      puts ("malloc failed, cannot test for overflow");
      return 0;
    }
  memset (p, 'x', SIZE);
  p[SIZE] = 0;
  printf ("%d\n", strcoll (p, p));
  return 0;
}