1 #include <string.h>

     2 #include <stdio.h>

     3 #include <stdlib.h>

     4 

     5 /*

     6   I used as environment the virtual machine provided here

     7 

     8     http://www.cis.upenn.edu/~cis551/box.tar

     9 

    10   This is Debian/Etch with Linux 2.6.18 with gcc 4.1.2 from 2008.

    11  

    12   Some installation notes for this virtual machine under VMWare

    13   are here

    14 

    15     http://www.cis.upenn.edu/~cis551/project1.pdf

    16 

    17   I run the virtial machine under MacOSX using the program 

    18   VirtualBox available for free from 

    19 

    20     https://www.virtualbox.org

    21 

    22   The C-program I compiled the program with 

    23 

    24     gcc -ggdb -fno-stack-protector -mpreferred-stack-boundary=2

    25 

    26  */

    27 

    28 

    29 void foo (char *bar)

    30 {

    31   float my_float = 10.5;    // in hex: \x41\x28\x00\x00

    32   char  buffer[28];        

    33 

    34   printf("my float value = %f\n", my_float);

    35 

    36   strcpy(buffer, bar);  

    37  

    38   printf("my float value = %f\n", my_float);

    39 }

    40  

    41 int main (int argc, char **argv)

    42 {

    43   foo("my string is too long !!!!! ");                  // all is normal

    44   foo("my string is too long !!!!! \x10\x10\xc0\x42");  // overwrites my_float

    45   return 0;

    46 }

    47