commit 6da1fb3f64d43be37e640efbec60400d1f1ac39e
 Author: Young_X <YangX92@hotmail.com>
 Date:   Sat Sep 8 14:46:27 2018 +0800
 
     avoid potential int32 overflows in multiply_ms()
 
 diff --git a/tools/ppm2tiff.c b/tools/ppm2tiff.c
 index af6e412..c2d5925 100644
 --- a/tools/ppm2tiff.c
 +++ b/tools/ppm2tiff.c
 @@ -70,15 +70,16 @@ BadPPM(char* file)
  	exit(-2);
  }
  
 +
 +#define TIFF_SIZE_T_MAX ((size_t) ~ ((size_t)0))
 +#define TIFF_TMSIZE_T_MAX (tmsize_t)(TIFF_SIZE_T_MAX >> 1)
 +
  static tmsize_t
  multiply_ms(tmsize_t m1, tmsize_t m2)
  {
 -	tmsize_t bytes = m1 * m2;
 -
 -	if (m1 && bytes / m1 != m2)
 -		bytes = 0;
 -
 -	return bytes;
 +        if( m1 == 0 || m2 > TIFF_TMSIZE_T_MAX / m1 )
 +            return 0;
 +        return m1 * m2;
  }
  
  int