Zenk-Security Wargame - Easy1 ASLR OFF

level.c

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

int main(int argc, char* argv[])
{
	if (argc != 2)
	{
		printf("Usage : prog filename\n");
		exit(1);
	}

	char com[61]  = "/bin/touch ";
	char com2[60] = "chmod 777 ";
	char name[50];
        int i;

        for (i=0; argv[1][i]!=0; i++)
        {
		if (argv[1][i] > 'z' || argv[1][i] < 'a')
		{
			printf("Not allowed char in filename\n");
                        exit(1);
		}
        }

	strncpy(name,argv[1],50);
	name[49] = '\0';

	strcat(com,name);
	strcat(com2,name);

	if (system(com) != 0)
	{
		printf("Permission denied\n");
		exit(1);
	}

	system(com2);
	return 0;
}