// SPDX-License-Identifier: MPL-2.0
#include <exception>
#include <sstream>
extern "C" {
#include "api.h"
#include "argon2.h"
#include "sha3.h"
}
#undef str
#include <fstream>
#include <filesystem>
#include <string>
#include <iostream>
#include <vector>
#include <map>
#include <string.h>
#include <sys/mman.h>
#include <sys/resource.h>
#include <sys/prctl.h>
#include <unistd.h>
#include <fcntl.h>
using namespace std;
namespace fs=filesystem;
const map<string,string> azerty_to_qwerty={
  {"a","q"},
  {"A","Q"},
  {"z","w"},
  {"Z","W"},
  {"q","a"},
  {"Q","A"},
  {"m",";"},
  {"M",":"},
  {"w","z"},
  {"W","Z"},
  {",","m"},
  {"?","M"},
  {"²","`"},
  {"&","1"},
  {"é","2"},
  {"\"","3"},
  {"'","4"},
  {"(","5"},
  {"-","6"},
  {"è","7"},
  {"_","8"},
  {"ç","9"},
  {"à","0"},
  {"~","2"},
  {"#","3"},
  {"{","4"},
  {"[","5"},
  {"|","6"},
  {"`","7"},
  {"\\","8"},
  {"^","9"},
  {"@","0"},
  {"1","!"},
  {"2","@"},
  {"3","#"},
  {"4","$"},
  {"5","%"},
  {"6","^"},
  {"7","&"},
  {"8","*"},
  {"9","("},
  {"0",")"},
  {";",","},
  {".","<"},
  {":","."},
  {"/",">"},
  {"!","/"},
  {"§","?"},
  {"<","\\"},
  {">","|"},
  {"ù","'"},
  {"%","\""},
  {"^","["},
  {"¨","{"},
  {"$","]"},
  {"£","}"},
  {"µ","|"}
};
void secure_erase(void *address,size_t size) {
  explicit_bzero(address,size);
}
vector<uint8_t> get_urandom(size_t n) {
  vector<uint8_t> out(n);
  ifstream urandom("/dev/urandom",ios::binary);
  if (!urandom.is_open()) {
    throw runtime_error("open");
  }
  urandom.read(reinterpret_cast<char*>(out.data()),n);
  if (urandom.gcount()!=static_cast<streamsize>(n)) {
    throw runtime_error("error");
  }
  return out;
}
int main(int argc,char **argv) {
  ofstream core("/proc/self/coredump_filter");
  if (!core) {
    cout<<"[Keygen] Error: can't setup security."<<endl;
    return -1;
  }
  core<<"0";
  core.close();
  if (prctl(PR_SET_DUMPABLE,0,0,0,0)!=0) {
    cout<<"[Keygen] Error: can't setup security."<<endl;
    return -1;
  }
  struct rlimit rl_mem;
  rl_mem.rlim_cur=(1<<31);
  rl_mem.rlim_max=(1<<31);
  if (setrlimit(RLIMIT_MEMLOCK,&rl_mem)!=0) {
    cout<<"[Keygen] Error: can't setup security."<<endl;
    return -1;
  }
  if (mlockall(MCL_CURRENT | MCL_FUTURE)!=0) {
    cout<<"[Keygen] Error: can't setup security."<<endl;
    return -1;
  }
  vector<string> files;
  if (argc>1) {
    for (int i=1;i<argc;++i) {
      files.push_back(string(argv[i]));
    }
  } else {
    cout<<"[Keygen] Error: no file provided."<<endl;
    return -1;
  }
  for (int i=0;i<files.size();i++) {
    if (!fs::exists(files[i])) {
      cout<<"[Keygen] Error: file "<<files[i]<<" don't exist."<<endl;
      return -1;
    }
  }
  vector<unsigned char> fbuf;
  vector<unsigned char> sigsbuf(files.size()*CRYPTO_BYTES);
  vector<unsigned char> pksbuf(files.size()*CRYPTO_PUBLICKEYBYTES);
  if (mlock(sigsbuf.data(),sigsbuf.size())!=0) {
    cout<<"[Keygen] Error: can't setup security."<<endl;
    return -1;
  }
  if (mlock(pksbuf.data(),pksbuf.size())!=0) {
    cout<<"[Keygen] Error: can't setup security."<<endl;
    return -1;
  }
  unsigned char pk[CRYPTO_PUBLICKEYBYTES];
  unsigned char sk[CRYPTO_SECRETKEYBYTES];
  mlock(pk,sizeof(pk));
  mlock(sk,sizeof(sk));
  madvise(pk,sizeof(pk),MADV_DONTDUMP);
  madvise(sk,sizeof(sk),MADV_DONTDUMP);
  unsigned char sig[CRYPTO_BYTES];
  mlock(sig,sizeof(sig));
  madvise(sig,sizeof(sig),MADV_DONTDUMP);
  for (int i=0;i<files.size();++i) {
    ifstream file_content(files[i],ios::binary);
    if (!file_content) {
      cout<<"[Keygen] Error: can't read file: "<<files[i]<<endl;
      return -1;
    }
    file_content.seekg(0,ios::end);
    streamsize size=file_content.tellg();
    file_content.seekg(0,ios::beg);
    fbuf.resize(size);
    if (!file_content.read(reinterpret_cast<char*>(fbuf.data()),size)) {
      cout<<"[Keygen] Error: can't read file: "<<files[i]<<endl;
      return -1;
    }
    if (crypto_sign_keypair(pk,sk)) {
      cout<<"[Keygen] Error: can't generate keypair for file: "<<files[i]<<endl;
      return -1;
    }
    size_t siglen;
    if (size<1024*1024) {
      if (crypto_sign_signature(sig,&siglen,fbuf.data(),fbuf.size(),sk)) {
        cout<<"[Keygen] Error: can't generate signature for file: "<<files[i]<<endl;
        secure_erase(pk,sizeof(pk));
        secure_erase(sk,sizeof(sk));
        secure_erase(sig,siglen);
        return -1;
      }
    } else {
      vector<unsigned char> hash(64);
      sha3(fbuf.data(),size,hash.data(),hash.size());
      if (crypto_sign_signature(sig,&siglen,hash.data(),hash.size(),sk)) {
        cout<<"[Keygen] Error: can't generate signature for file: "<<files[i]<<endl;
        secure_erase(pk,sizeof(pk));
        secure_erase(sk,sizeof(sk));
        secure_erase(sig,siglen);
        return -1;
      }
    }
    if (siglen!=CRYPTO_BYTES) {
      cout<<"[Keygen] Error: signature isn't the expected size for file: "<<files[i]<<endl;
      secure_erase(pk,sizeof(pk));
      secure_erase(sk,sizeof(sk));
      secure_erase(sig,siglen);
      return -1;
    }
    memcpy(&pksbuf[i*CRYPTO_PUBLICKEYBYTES],pk,CRYPTO_PUBLICKEYBYTES);
    memcpy(&sigsbuf[i*CRYPTO_BYTES],sig,CRYPTO_BYTES);
    secure_erase(sk,sizeof(sk));
    secure_erase(pk,sizeof(pk));
    secure_erase(sig,siglen);
    if (!fbuf.empty()) {
      secure_erase(fbuf.data(),fbuf.size());
      fbuf.clear();
    }
  }
  if (!filesystem::exists("./sign")) {
    filesystem::create_directory("./sign");
  }
  for (int i=0;i<files.size();i++) {
    ofstream sigfile("./sign/"+fs::path(files[i]).filename().string()+".sig",ios::binary);
    if (!sigfile) {
      cout<<"[Keygen] Error: can't open signature file for file: "<<files[i]<<endl;
      return -1;
    }
    sigfile.write(reinterpret_cast<const char*>(sigsbuf.data()+i*CRYPTO_BYTES),CRYPTO_BYTES);
    sigfile.close();
  }
  secure_erase(sigsbuf.data(),sigsbuf.size());
  cout<<"[Keygen] You are about to define a boot password. This password will be asked everytime you boot this instance of Vystem."<<endl;
  cout<<"[Keygen] It will be used to sign every public key on this instance of Vystem. Make sure it's secure. Here are the requirements:\n  - It should be at least 12 characters.\n  - Password can only include ASCII characters.\n  - Password shouldn't be longer than 512 characters.\n  - DO NOT use the numerical pad at all. It's not supported in the EFI environment."<<endl;
  cout<<"[Keygen] Leave empty for us to generate entropy as a password."<<endl;
  char* pwd=getpass("[Keygen] Enter boot password: ");
  string password;
  if (strlen(pwd)==0) {
    cout<<"[Keygen] You asked for entropy. It will be provided as hexadecimal characters. Please enter the amount of hexadecimal characters you want."<<endl;
    cout<<"[Keygen] The amount of hex characters shouldn't be bigger than 512."<<endl;
    cout<<"[Keygen] Amount of hex characters (should be a multiple of 2 and at least 16 characters to be a minimum secure): ";
    string amount;
    getline(cin,amount);
    uint64_t num;
    try {
      num=stoi(amount);
    } catch (const exception e) {
      cout<<"[Keygen] Value entered isn't a number. Using default amount of 16 characters."<<endl;
      num=8;
    }
    if (num%2!=0) {
      cout<<"[Keygen] Number entered isn't a multiple of 2. Using default amount of 16 characters."<<endl;
      num=8;
    } else if (num<513) {
      num=num/2;
    } else {
      cout<<"[Keygen] Error: password is too long."<<endl;
      return -1;
    }
    vector<uint8_t> passhex;
    passhex.resize(num);
    try {
      passhex=get_urandom(num);
    } catch (const exception e) {
      if (string(e.what())=="open") {
        cout<<"[Keygen] Error: can't open secure source of randomness."<<endl;
        return -1;
      } else if (string(e.what())=="error") {
        cout<<"[Keygen] Error: can't read enought secure entropy."<<endl;
        return -1;
      }
    }
    ostringstream oss;
    oss<<hex<<setfill('0');
    for (uint8_t byte:passhex) {
      oss<<setw(2)<<std::uppercase<<static_cast<int>(byte);
    }
    password=oss.str();
    secure_erase(passhex.data(),passhex.size());
  } else if (strlen(pwd)<=512){
    password=string(pwd);
    char* confirm_pwd=getpass("[Keygen] Confirm password: ");
    string confirm_password(confirm_pwd);
    if (confirm_password!=password) {
      cout<<"[Keygen] Error: password don't correspond. Please try again."<<endl;
      return -1;
    }
    secure_erase(confirm_pwd,strlen(confirm_pwd));
  } else {
    cout<<"[Keygen] Error: password is too long."<<endl;
    return -1;
  }
  string pass=password;
  string rep;
  cout<<"[Keygen] Do you use a keyboard with another layout than QWERTY (y/N) ? : ";
  getline(cin,rep);
  if (rep=="y") {
    cout<<"[Keygen] Do you want to automatically translate your password into what it should look like into a QWERTY layout (y/N) ?"<<endl;
    cout<<"[Keygen] Please note that for the moment, only AZERTY to QWERTY is supported."<<endl;
    cout<<"[Keygen] Your answer : ";
    getline(cin,rep);
    if (rep=="y") {
      for (int i=0;i<password.size();i++) {
        try {
          password[i]=azerty_to_qwerty.at(string(1,password.at(i)))[0];
        } catch (const exception e) {
          continue;
        }
      }
    } else {
      cout<<"[Keygen] Skipping password translation."<<endl;
    }
  } else {
    cout<<"[Keygen] No password translation needed."<<endl;
  }
  cout<<"[Keygen] Your password is set to be: "<<pass<<endl;
  cout<<"[Keygen] The password that will be hashed is: "<<password<<endl;
  cout<<"[Keygen] If you have a keyboard layout other than QWERTY and didn't selected to translate it, you will have to type the second provided password."<<endl;
  cout<<"[Keygen] If you have a keyboard layout other than QWERTY and selected to translate it, just type it like you would do in your keyboard layout."<<endl;
  cout<<"[Keygen] If you don't remember it or write it down somewhere else, you will not be able to boot into your system."<<endl;
  cout<<"[Keygen] Press enter to continue.";
  string dummy;
  getline(cin,dummy);
  cout<<endl;
  secure_erase(pwd,strlen(pwd));
  for (unsigned char c:password) {
    if (c>=0x80) {
      cout<<"[Keygen] Error: one character isn't ASCII."<<endl;
      return -1;
    }
  }
  vector<unsigned char> passutf16(password.size()*2);
  for (int i=0;i<password.size();++i) {
    passutf16[i*2]=password[i];
    passutf16[i*2+1]=0x00;
  }
  vector<uint8_t> salt(32);
  salt=get_urandom(32);
  vector<unsigned char> seed;
  seed.resize(CRYPTO_SEEDBYTES);
  if (argon2id_hash_raw(3,262144,1,passutf16.data(),passutf16.size(),salt.data(),salt.size(),seed.data(),CRYPTO_SEEDBYTES)!=0) {
    cout<<"[Keygen] Error: can't generate seed from password."<<endl;
    return -1;
  }
  if (crypto_sign_seed_keypair(pk,sk,seed.data())!=0) {
    cout<<"[Keygen] Error: can't generate keys from seed."<<endl;
    return -1;
  }
  secure_erase(pk,sizeof(pk));
  secure_erase(seed.data(),seed.size());
  size_t siglen;
  if (crypto_sign_signature(sig,&siglen,pksbuf.data(),pksbuf.size(),sk)!=0) {
    cout<<"[Keygen] Error: can't generate signature from all publics keys."<<endl;
    return -1;
  }
  secure_erase(sk,sizeof(sk));
  ofstream keyfile("key.h");
  keyfile<<"#ifndef BP_LIB_KEY_H\n#define BP_LIB_KEY_H\n#include <Uefi.h>\nUINT8 bp_key_mainsig["<<to_string(CRYPTO_BYTES)<<"]={";
  for (int i=0;i<CRYPTO_BYTES;++i) {
    keyfile<<"0x"<<hex<<setw(2)<<setfill('0')<<(int)sig[i];
    if (i+1!=CRYPTO_BYTES) keyfile<<",";
  }
  keyfile<<"};\nUINT8 bp_key_pkblob["<<to_string(pksbuf.size())<<"]={";
  for (int i=0;i<pksbuf.size();++i) {
    keyfile<<"0x"<<hex<<setw(2)<<setfill('0')<<(int)pksbuf[i];
    if (i+1!=pksbuf.size()) keyfile<<",";
  }
  keyfile<<"};\nUINT8 bp_key_pwdsalt["<<to_string(salt.size())<<"]={";
  for (int i=0;i<salt.size();++i) {
    keyfile<<"0x"<<hex<<setw(2)<<setfill('0')<<(int)salt[i];
    if (i+1!=salt.size()) keyfile<<",";
  }
  keyfile<<"};\nSTATIC const CHAR16 * const bp_key_files["<<files.size()<<"]={";
  for (int i=0;i<files.size();++i) {
    keyfile<<"L\""<<fs::path(files[i]).filename().string()+"\"";
    if (i+1!=files.size()) keyfile<<",";
  }
  keyfile<<"};\n#endif";
  keyfile.close();
  return 0;
}