/*
 * phoenix/stack-five, by https://exploit.education
 *
 * Can you execve("/bin/sh", ...) ?
 *
 * What is green and goes to summer camp? A brussel scout.
 */

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

#define BANNER \
  "Welcome to " LEVELNAME ", brought to you by https://exploit.education"

char *gets(char *);

void start_level() {
  char buffer[128];
  gets(buffer);
}

int main(int argc, char **argv) {
  printf("%s\n", BANNER);
  start_level();
}

/*
 * phoenix/stack-four, by https://exploit.education
 *
 * The aim is to execute the function complete_level by modifying the
 * saved return address, and pointing it to the complete_level() function.
 *
 * Why were the apple and orange all alone? Because the bananna split.
 */

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

#define BANNER \
  "Welcome to " LEVELNAME ", brought to you by https://exploit.education"

char *gets(char *);

void complete_level() {
  printf("Congratulations, you've finished " LEVELNAME " :-) Well done!\n");
  exit(0);
}

void start_level() {
  char buffer[64];
  void *ret;

  gets(buffer);

  ret = __builtin_return_address(0);
  printf("and will be returning to %p\n", ret);
}

int main(int argc, char **argv) {
  printf("%s\n", BANNER);
  start_level();
}

/*
 * phoenix/stack-three, by https://exploit.education
 *
 * The aim is to change the contents of the changeme variable to 0x0d0a090a
 *
 * When does a joke become a dad joke?
 *   When it becomes apparent.
 *   When it's fully groan up.
 *
 */

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

#define BANNER \
  "Welcome to " LEVELNAME ", brought to you by https://exploit.education"

char *gets(char *);

void complete_level() {
  printf("Congratulations, you've finished " LEVELNAME " :-) Well done!\n");
  exit(0);
}

int main(int argc, char **argv) {
  struct {
    char buffer[64];
    volatile int (*fp)();
  } locals;

  printf("%s\n", BANNER);

  locals.fp = NULL;
  gets(locals.buffer);

  if (locals.fp) {
    printf("calling function pointer @ %p\n", locals.fp);
    fflush(stdout);
    locals.fp();
  } else {
    printf("function pointer remains unmodified :~( better luck next time!\n");
  }

  exit(0);
}

/*
 * phoenix/stack-one, by https://exploit.education
 *
 * The aim is to change the contents of the changeme variable to 0x496c5962
 *
 * Did you hear about the kid napping at the local school?
 * It's okay, they woke up.
 *
 */

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

#define BANNER \
  "Welcome to " LEVELNAME ", brought to you by https://exploit.education"

int main(int argc, char **argv) {
  struct {
    char buffer[64];
    volatile int changeme;
  } locals;

  printf("%s\n", BANNER);

  if (argc < 2) {
    errx(1, "specify an argument, to be copied into the \"buffer\"");
  }

  locals.changeme = 0;
  strcpy(locals.buffer, argv[1]);

  if (locals.changeme == 0x496c5962) {
    puts("Well done, you have successfully set changeme to the correct value");
  } else {
    printf("Getting closer! changeme is currently 0x%08x, we want 0x496c5962\n",
        locals.changeme);
  }

  exit(0);
}

/*
 * phoenix/stack-zero, by https://exploit.education
 *
 * The aim is to change the contents of the changeme variable.
 *
 * Scientists have recently discovered a previously unknown species of
 * kangaroos, approximately in the middle of Western Australia. These
 * kangaroos are remarkable, as their insanely powerful hind legs give them
 * the ability to jump higher than a one story house (which is approximately
 * 15 feet, or 4.5 metres), simply because houses can't can't jump.
 */

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

#define BANNER \
  "Welcome to " LEVELNAME ", brought to you by https://exploit.education"

char *gets(char *);

int main(int argc, char **argv) {
  struct {
    char buffer[64];
    volatile int changeme;
  } locals;

  printf("%s\n", BANNER);

  locals.changeme = 0;
  gets(locals.buffer);

  if (locals.changeme != 0) {
    puts("Well done, the 'changeme' variable has been changed!");
  } else {
    puts(
        "Uh oh, 'changeme' has not yet been changed. Would you like to try "
        "again?");
  }

  exit(0);
}