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GCC Code Coverage Report
Directory:	./		Exec	Total	Coverage
File:	crypto/crypto_cipher.cc	Lines:	446	488	91.4 %
Date:	2021-10-01 04:12:33	Branches:	346	483	71.6 %

#include "crypto/crypto_cipher.h"
#include "crypto/crypto_util.h"
#include "allocated_buffer-inl.h"
#include "base_object-inl.h"
#include "env-inl.h"
#include "memory_tracker-inl.h"
#include "node_buffer.h"
#include "node_internals.h"
#include "node_process-inl.h"
#include "v8.h"

namespace node {

using v8::Array;
using v8::FunctionCallbackInfo;
using v8::FunctionTemplate;
using v8::HandleScope;
using v8::Int32;
using v8::Local;
using v8::Object;
using v8::Uint32;
using v8::Value;

namespace crypto {
#ifdef OPENSSL_NO_OCB
# define IS_OCB_MODE(mode) false
#else
# define IS_OCB_MODE(mode) ((mode) == EVP_CIPH_OCB_MODE)
#endif

namespace {
bool IsSupportedAuthenticatedMode(const EVP_CIPHER* cipher) {
  const int mode = EVP_CIPHER_mode(cipher);
  // Check `chacha20-poly1305` separately, it is also an AEAD cipher,
  // but its mode is 0 which doesn't indicate
  return EVP_CIPHER_nid(cipher) == NID_chacha20_poly1305 ||
         mode == EVP_CIPH_CCM_MODE ||
         mode == EVP_CIPH_GCM_MODE ||
         IS_OCB_MODE(mode);
}

bool IsSupportedAuthenticatedMode(const EVP_CIPHER_CTX* ctx) {
  const EVP_CIPHER* cipher = EVP_CIPHER_CTX_cipher(ctx);
  return IsSupportedAuthenticatedMode(cipher);
}

bool IsValidGCMTagLength(unsigned int tag_len) {
  return tag_len == 4 || tag_len == 8 || (tag_len >= 12 && tag_len <= 16);
}

// Collects and returns information on the given cipher
void GetCipherInfo(const FunctionCallbackInfo<Value>& args) {
  Environment* env = Environment::GetCurrent(args);
  CHECK(args[0]->IsObject());
  Local<Object> info = args[0].As<Object>();

  CHECK(args[1]->IsString() || args[1]->IsInt32());

  const EVP_CIPHER* cipher;
  if (args[1]->IsString()) {
    Utf8Value name(env->isolate(), args[1]);
    cipher = EVP_get_cipherbyname(*name);
  } else {
    int nid = args[1].As<Int32>()->Value();
    cipher = EVP_get_cipherbynid(nid);
  }

  if (cipher == nullptr)
    return;

  int mode = EVP_CIPHER_mode(cipher);
  int iv_length = EVP_CIPHER_iv_length(cipher);
  int key_length = EVP_CIPHER_key_length(cipher);
  int block_length = EVP_CIPHER_block_size(cipher);
  const char* mode_label = nullptr;
  switch (mode) {
    case EVP_CIPH_CBC_MODE: mode_label = "cbc"; break;
    case EVP_CIPH_CCM_MODE: mode_label = "ccm"; break;
    case EVP_CIPH_CFB_MODE: mode_label = "cfb"; break;
    case EVP_CIPH_CTR_MODE: mode_label = "ctr"; break;
    case EVP_CIPH_ECB_MODE: mode_label = "ecb"; break;
    case EVP_CIPH_GCM_MODE: mode_label = "gcm"; break;
    case EVP_CIPH_OCB_MODE: mode_label = "ocb"; break;
    case EVP_CIPH_OFB_MODE: mode_label = "ofb"; break;
    case EVP_CIPH_WRAP_MODE: mode_label = "wrap"; break;
    case EVP_CIPH_XTS_MODE: mode_label = "xts"; break;
    case EVP_CIPH_STREAM_CIPHER: mode_label = "stream"; break;
  }

  // If the testKeyLen and testIvLen arguments are specified,
  // then we will make an attempt to see if they are usable for
  // the cipher in question, returning undefined if they are not.
  // If they are, the info object will be returned with the values
  // given.
  if (args[2]->IsInt32() || args[3]->IsInt32()) {
    // Test and input IV or key length to determine if it's acceptable.
    // If it is, then the getCipherInfo will succeed with the given
    // values.
    CipherCtxPointer ctx(EVP_CIPHER_CTX_new());
    if (!EVP_CipherInit_ex(ctx.get(), cipher, nullptr, nullptr, nullptr, 1))
      return;

    if (args[2]->IsInt32()) {
      int check_len = args[2].As<Int32>()->Value();
      if (!EVP_CIPHER_CTX_set_key_length(ctx.get(), check_len))
        return;
      key_length = check_len;
    }

    if (args[3]->IsInt32()) {
      int check_len = args[3].As<Int32>()->Value();
      // For CCM modes, the IV may be between 7 and 13 bytes.
      // For GCM and OCB modes, we'll check by attempting to
      // set the value. For everything else, just check that
      // check_len == iv_length.
      switch (mode) {
        case EVP_CIPH_CCM_MODE:
          if (check_len < 7 || check_len > 13)
            return;
          break;
        case EVP_CIPH_GCM_MODE:
          // Fall through
        case EVP_CIPH_OCB_MODE:
          if (!EVP_CIPHER_CTX_ctrl(
                  ctx.get(),
                  EVP_CTRL_AEAD_SET_IVLEN,
                  check_len,
                  nullptr)) {
            return;
          }
          break;
        default:
          if (check_len != iv_length)
            return;
      }
      iv_length = check_len;
    }
  }

  if (mode_label != nullptr &&
      info->Set(
          env->context(),
          FIXED_ONE_BYTE_STRING(env->isolate(), "mode"),
          OneByteString(env->isolate(), mode_label)).IsNothing()) {
    return;
  }

  // OBJ_nid2sn(EVP_CIPHER_nid(cipher)) is used here instead of
  // EVP_CIPHER_name(cipher) for compatibility with BoringSSL.
  if (info->Set(
          env->context(),
          env->name_string(),
          OneByteString(
            env->isolate(),
            OBJ_nid2sn(EVP_CIPHER_nid(cipher)))).IsNothing()) {
    return;
  }

  if (info->Set(
          env->context(),
          FIXED_ONE_BYTE_STRING(env->isolate(), "nid"),
          Int32::New(env->isolate(), EVP_CIPHER_nid(cipher))).IsNothing()) {
    return;
  }

  // Stream ciphers do not have a meaningful block size
  if (mode != EVP_CIPH_STREAM_CIPHER &&
      info->Set(
          env->context(),
          FIXED_ONE_BYTE_STRING(env->isolate(), "blockSize"),
          Int32::New(env->isolate(), block_length)).IsNothing()) {
    return;
  }

  // Ciphers that do not use an IV shouldn't report a length
  if (iv_length != 0 &&
      info->Set(
          env->context(),
          FIXED_ONE_BYTE_STRING(env->isolate(), "ivLength"),
          Int32::New(env->isolate(), iv_length)).IsNothing()) {
    return;
  }

  if (info->Set(
          env->context(),
          FIXED_ONE_BYTE_STRING(env->isolate(), "keyLength"),
          Int32::New(env->isolate(), key_length)).IsNothing()) {
    return;
  }

  args.GetReturnValue().Set(info);
}
}  // namespace

void CipherBase::GetSSLCiphers(const FunctionCallbackInfo<Value>& args) {
  Environment* env = Environment::GetCurrent(args);

  SSLCtxPointer ctx(SSL_CTX_new(TLS_method()));
  CHECK(ctx);

  SSLPointer ssl(SSL_new(ctx.get()));
  CHECK(ssl);

  STACK_OF(SSL_CIPHER)* ciphers = SSL_get_ciphers(ssl.get());

  // TLSv1.3 ciphers aren't listed by EVP. There are only 5, we could just
  // document them, but since there are only 5, easier to just add them manually
  // and not have to explain their absence in the API docs. They are lower-cased
  // because the docs say they will be.
  static const char* TLS13_CIPHERS[] = {
    "tls_aes_256_gcm_sha384",
    "tls_chacha20_poly1305_sha256",
    "tls_aes_128_gcm_sha256",
    "tls_aes_128_ccm_8_sha256",
    "tls_aes_128_ccm_sha256"
  };

  const int n = sk_SSL_CIPHER_num(ciphers);
  std::vector<Local<Value>> arr(n + arraysize(TLS13_CIPHERS));

  for (int i = 0; i < n; ++i) {
    const SSL_CIPHER* cipher = sk_SSL_CIPHER_value(ciphers, i);
    arr[i] = OneByteString(env->isolate(), SSL_CIPHER_get_name(cipher));
  }

  for (unsigned i = 0; i < arraysize(TLS13_CIPHERS); ++i) {
    const char* name = TLS13_CIPHERS[i];
    arr[n + i] = OneByteString(env->isolate(), name);
  }

  args.GetReturnValue().Set(Array::New(env->isolate(), arr.data(), arr.size()));
}

void CipherBase::GetCiphers(const FunctionCallbackInfo<Value>& args) {
  Environment* env = Environment::GetCurrent(args);
  CipherPushContext ctx(env);
  EVP_CIPHER_do_all_sorted(array_push_back<EVP_CIPHER>, &ctx);
  args.GetReturnValue().Set(ctx.ToJSArray());
}

CipherBase::CipherBase(Environment* env,
                       Local<Object> wrap,
                       CipherKind kind)
    : BaseObject(env, wrap),
      ctx_(nullptr),
      kind_(kind),
      auth_tag_state_(kAuthTagUnknown),
      auth_tag_len_(kNoAuthTagLength),
      pending_auth_failed_(false) {
  MakeWeak();
}

void CipherBase::MemoryInfo(MemoryTracker* tracker) const {
  tracker->TrackFieldWithSize("context", ctx_ ? kSizeOf_EVP_CIPHER_CTX : 0);
}

void CipherBase::Initialize(Environment* env, Local<Object> target) {
  Local<FunctionTemplate> t = env->NewFunctionTemplate(New);

  t->InstanceTemplate()->SetInternalFieldCount(
      CipherBase::kInternalFieldCount);
  t->Inherit(BaseObject::GetConstructorTemplate(env));

  env->SetProtoMethod(t, "init", Init);
  env->SetProtoMethod(t, "initiv", InitIv);
  env->SetProtoMethod(t, "update", Update);
  env->SetProtoMethod(t, "final", Final);
  env->SetProtoMethod(t, "setAutoPadding", SetAutoPadding);
  env->SetProtoMethodNoSideEffect(t, "getAuthTag", GetAuthTag);
  env->SetProtoMethod(t, "setAuthTag", SetAuthTag);
  env->SetProtoMethod(t, "setAAD", SetAAD);
  env->SetConstructorFunction(target, "CipherBase", t);

  env->SetMethodNoSideEffect(target, "getSSLCiphers", GetSSLCiphers);
  env->SetMethodNoSideEffect(target, "getCiphers", GetCiphers);

  env->SetMethod(target, "publicEncrypt",
                 PublicKeyCipher::Cipher<PublicKeyCipher::kPublic,
                                         EVP_PKEY_encrypt_init,
                                         EVP_PKEY_encrypt>);
  env->SetMethod(target, "privateDecrypt",
                 PublicKeyCipher::Cipher<PublicKeyCipher::kPrivate,
                                         EVP_PKEY_decrypt_init,
                                         EVP_PKEY_decrypt>);
  env->SetMethod(target, "privateEncrypt",
                 PublicKeyCipher::Cipher<PublicKeyCipher::kPrivate,
                                         EVP_PKEY_sign_init,
                                         EVP_PKEY_sign>);
  env->SetMethod(target, "publicDecrypt",
                 PublicKeyCipher::Cipher<PublicKeyCipher::kPublic,
                                         EVP_PKEY_verify_recover_init,
                                         EVP_PKEY_verify_recover>);

  env->SetMethodNoSideEffect(target, "getCipherInfo", GetCipherInfo);

  NODE_DEFINE_CONSTANT(target, kWebCryptoCipherEncrypt);
  NODE_DEFINE_CONSTANT(target, kWebCryptoCipherDecrypt);
}

void CipherBase::New(const FunctionCallbackInfo<Value>& args) {
  CHECK(args.IsConstructCall());
  Environment* env = Environment::GetCurrent(args);
  new CipherBase(env, args.This(), args[0]->IsTrue() ? kCipher : kDecipher);
}

void CipherBase::CommonInit(const char* cipher_type,
                            const EVP_CIPHER* cipher,
                            const unsigned char* key,
                            int key_len,
                            const unsigned char* iv,
                            int iv_len,
                            unsigned int auth_tag_len) {
  CHECK(!ctx_);
  ctx_.reset(EVP_CIPHER_CTX_new());

  const int mode = EVP_CIPHER_mode(cipher);
  if (mode == EVP_CIPH_WRAP_MODE)
    EVP_CIPHER_CTX_set_flags(ctx_.get(), EVP_CIPHER_CTX_FLAG_WRAP_ALLOW);

  const bool encrypt = (kind_ == kCipher);
  if (1 != EVP_CipherInit_ex(ctx_.get(), cipher, nullptr,
                             nullptr, nullptr, encrypt)) {
    return ThrowCryptoError(env(), ERR_get_error(),
                            "Failed to initialize cipher");
  }

  if (IsSupportedAuthenticatedMode(cipher)) {
    CHECK_GE(iv_len, 0);
    if (!InitAuthenticated(cipher_type, iv_len, auth_tag_len))
      return;
  }

  if (!EVP_CIPHER_CTX_set_key_length(ctx_.get(), key_len)) {
    ctx_.reset();
    return THROW_ERR_CRYPTO_INVALID_KEYLEN(env());
  }

  if (1 != EVP_CipherInit_ex(ctx_.get(), nullptr, nullptr, key, iv, encrypt)) {
    return ThrowCryptoError(env(), ERR_get_error(),
                            "Failed to initialize cipher");
  }
}

void CipherBase::Init(const char* cipher_type,
                      const ArrayBufferOrViewContents<unsigned char>& key_buf,
                      unsigned int auth_tag_len) {
  HandleScope scope(env()->isolate());
  MarkPopErrorOnReturn mark_pop_error_on_return;
#if OPENSSL_VERSION_MAJOR >= 3
  if (EVP_default_properties_is_fips_enabled(nullptr)) {
#else
  if (FIPS_mode()) {
#endif
    return THROW_ERR_CRYPTO_UNSUPPORTED_OPERATION(env(),
        "crypto.createCipher() is not supported in FIPS mode.");
  }

  const EVP_CIPHER* const cipher = EVP_get_cipherbyname(cipher_type);
  if (cipher == nullptr)
    return THROW_ERR_CRYPTO_UNKNOWN_CIPHER(env());

  unsigned char key[EVP_MAX_KEY_LENGTH];
  unsigned char iv[EVP_MAX_IV_LENGTH];

  int key_len = EVP_BytesToKey(cipher,
                               EVP_md5(),
                               nullptr,
                               key_buf.data(),
                               key_buf.size(),
                               1,
                               key,
                               iv);
  CHECK_NE(key_len, 0);

  const int mode = EVP_CIPHER_mode(cipher);
  if (kind_ == kCipher && (mode == EVP_CIPH_CTR_MODE ||
                           mode == EVP_CIPH_GCM_MODE ||
                           mode == EVP_CIPH_CCM_MODE)) {
    // Ignore the return value (i.e. possible exception) because we are
    // not calling back into JS anyway.
    ProcessEmitWarning(env(),
                       "Use Cipheriv for counter mode of %s",
                       cipher_type);
  }

  CommonInit(cipher_type, cipher, key, key_len, iv,
             EVP_CIPHER_iv_length(cipher), auth_tag_len);
}

void CipherBase::Init(const FunctionCallbackInfo<Value>& args) {
  CipherBase* cipher;
  ASSIGN_OR_RETURN_UNWRAP(&cipher, args.Holder());
  Environment* env = Environment::GetCurrent(args);

  CHECK_GE(args.Length(), 3);

  const Utf8Value cipher_type(args.GetIsolate(), args[0]);
  ArrayBufferOrViewContents<unsigned char> key_buf(args[1]);
  if (!key_buf.CheckSizeInt32())
    return THROW_ERR_OUT_OF_RANGE(env, "password is too large");

  // Don't assign to cipher->auth_tag_len_ directly; the value might not
  // represent a valid length at this point.
  unsigned int auth_tag_len;
  if (args[2]->IsUint32()) {
    auth_tag_len = args[2].As<Uint32>()->Value();
  } else {
    CHECK(args[2]->IsInt32() && args[2].As<Int32>()->Value() == -1);
    auth_tag_len = kNoAuthTagLength;
  }

  cipher->Init(*cipher_type, key_buf, auth_tag_len);
}

void CipherBase::InitIv(const char* cipher_type,
                        const ByteSource& key_buf,
                        const ArrayBufferOrViewContents<unsigned char>& iv_buf,
                        unsigned int auth_tag_len) {
  HandleScope scope(env()->isolate());
  MarkPopErrorOnReturn mark_pop_error_on_return;

  const EVP_CIPHER* const cipher = EVP_get_cipherbyname(cipher_type);
  if (cipher == nullptr)
    return THROW_ERR_CRYPTO_UNKNOWN_CIPHER(env());

  const int expected_iv_len = EVP_CIPHER_iv_length(cipher);
  const bool is_authenticated_mode = IsSupportedAuthenticatedMode(cipher);
  const bool has_iv = iv_buf.size() > 0;

  // Throw if no IV was passed and the cipher requires an IV
  if (!has_iv && expected_iv_len != 0)
    return THROW_ERR_CRYPTO_INVALID_IV(env());

  // Throw if an IV was passed which does not match the cipher's fixed IV length
  // static_cast<int> for the iv_buf.size() is safe because we've verified
  // prior that the value is not larger than MAX_INT.
  if (!is_authenticated_mode &&
      has_iv &&
      static_cast<int>(iv_buf.size()) != expected_iv_len) {
    return THROW_ERR_CRYPTO_INVALID_IV(env());
  }

  if (EVP_CIPHER_nid(cipher) == NID_chacha20_poly1305) {
    CHECK(has_iv);
    // Check for invalid IV lengths, since OpenSSL does not under some
    // conditions:
    //   https://www.openssl.org/news/secadv/20190306.txt.
    if (iv_buf.size() > 12)
      return THROW_ERR_CRYPTO_INVALID_IV(env());
  }

  CommonInit(
      cipher_type,
      cipher,
      key_buf.data<unsigned char>(),
      key_buf.size(),
      iv_buf.data(),
      iv_buf.size(),
      auth_tag_len);
}

void CipherBase::InitIv(const FunctionCallbackInfo<Value>& args) {
  CipherBase* cipher;
  ASSIGN_OR_RETURN_UNWRAP(&cipher, args.Holder());
  Environment* env = cipher->env();

  CHECK_GE(args.Length(), 4);

  const Utf8Value cipher_type(env->isolate(), args[0]);

  // The argument can either be a KeyObjectHandle or a byte source
  // (e.g. ArrayBuffer, TypedArray, etc). Whichever it is, grab the
  // raw bytes and proceed...
  const ByteSource key_buf = ByteSource::FromSecretKeyBytes(env, args[1]);

  if (UNLIKELY(key_buf.size() > INT_MAX))
    return THROW_ERR_OUT_OF_RANGE(env, "key is too big");

  ArrayBufferOrViewContents<unsigned char> iv_buf;
  if (!args[2]->IsNull())
    iv_buf = ArrayBufferOrViewContents<unsigned char>(args[2]);

  if (UNLIKELY(!iv_buf.CheckSizeInt32()))
    return THROW_ERR_OUT_OF_RANGE(env, "iv is too big");

  // Don't assign to cipher->auth_tag_len_ directly; the value might not
  // represent a valid length at this point.
  unsigned int auth_tag_len;
  if (args[3]->IsUint32()) {
    auth_tag_len = args[3].As<Uint32>()->Value();
  } else {
    CHECK(args[3]->IsInt32() && args[3].As<Int32>()->Value() == -1);
    auth_tag_len = kNoAuthTagLength;
  }

  cipher->InitIv(*cipher_type, key_buf, iv_buf, auth_tag_len);
}

bool CipherBase::InitAuthenticated(
    const char* cipher_type,
    int iv_len,
    unsigned int auth_tag_len) {
  CHECK(IsAuthenticatedMode());
  MarkPopErrorOnReturn mark_pop_error_on_return;

  if (!EVP_CIPHER_CTX_ctrl(ctx_.get(),
                           EVP_CTRL_AEAD_SET_IVLEN,
                           iv_len,
                           nullptr)) {
    THROW_ERR_CRYPTO_INVALID_IV(env());
    return false;
  }

  const int mode = EVP_CIPHER_CTX_mode(ctx_.get());
  if (mode == EVP_CIPH_GCM_MODE) {
    if (auth_tag_len != kNoAuthTagLength) {
      if (!IsValidGCMTagLength(auth_tag_len)) {
        THROW_ERR_CRYPTO_INVALID_AUTH_TAG(
          env(),
          "Invalid authentication tag length: %u",
          auth_tag_len);
        return false;
      }

      // Remember the given authentication tag length for later.
      auth_tag_len_ = auth_tag_len;
    }
  } else {
    if (auth_tag_len == kNoAuthTagLength) {
      THROW_ERR_CRYPTO_INVALID_AUTH_TAG(
        env(), "authTagLength required for %s", cipher_type);
      return false;
    }

    // TODO(tniessen) Support CCM decryption in FIPS mode

#if OPENSSL_VERSION_MAJOR >= 3
    if (mode == EVP_CIPH_CCM_MODE && kind_ == kDecipher &&
        EVP_default_properties_is_fips_enabled(nullptr)) {
#else
    if (mode == EVP_CIPH_CCM_MODE && kind_ == kDecipher && FIPS_mode()) {
#endif
      THROW_ERR_CRYPTO_UNSUPPORTED_OPERATION(env(),
          "CCM encryption not supported in FIPS mode");
      return false;
    }

    // Tell OpenSSL about the desired length.
    if (!EVP_CIPHER_CTX_ctrl(ctx_.get(), EVP_CTRL_AEAD_SET_TAG, auth_tag_len,
                             nullptr)) {
      THROW_ERR_CRYPTO_INVALID_AUTH_TAG(env());
      return false;
    }

    // Remember the given authentication tag length for later.
    auth_tag_len_ = auth_tag_len;

    if (mode == EVP_CIPH_CCM_MODE) {
      // Restrict the message length to min(INT_MAX, 2^(8*(15-iv_len))-1) bytes.
      CHECK(iv_len >= 7 && iv_len <= 13);
      max_message_size_ = INT_MAX;
      if (iv_len == 12) max_message_size_ = 16777215;
      if (iv_len == 13) max_message_size_ = 65535;
    }
  }

  return true;
}

bool CipherBase::CheckCCMMessageLength(int message_len) {
  CHECK(ctx_);
  CHECK(EVP_CIPHER_CTX_mode(ctx_.get()) == EVP_CIPH_CCM_MODE);

  if (message_len > max_message_size_) {
    THROW_ERR_CRYPTO_INVALID_MESSAGELEN(env());
    return false;
  }

  return true;
}

bool CipherBase::IsAuthenticatedMode() const {
  // Check if this cipher operates in an AEAD mode that we support.
  CHECK(ctx_);
  return IsSupportedAuthenticatedMode(ctx_.get());
}

void CipherBase::GetAuthTag(const FunctionCallbackInfo<Value>& args) {
  Environment* env = Environment::GetCurrent(args);
  CipherBase* cipher;
  ASSIGN_OR_RETURN_UNWRAP(&cipher, args.Holder());

  // Only callable after Final and if encrypting.
  if (cipher->ctx_ ||
      cipher->kind_ != kCipher ||
      cipher->auth_tag_len_ == kNoAuthTagLength) {
    return;
  }

  args.GetReturnValue().Set(
      Buffer::Copy(env, cipher->auth_tag_, cipher->auth_tag_len_)
          .FromMaybe(Local<Value>()));
}

void CipherBase::SetAuthTag(const FunctionCallbackInfo<Value>& args) {
  CipherBase* cipher;
  ASSIGN_OR_RETURN_UNWRAP(&cipher, args.Holder());
  Environment* env = Environment::GetCurrent(args);

  if (!cipher->ctx_ ||
      !cipher->IsAuthenticatedMode() ||
      cipher->kind_ != kDecipher ||
      cipher->auth_tag_state_ != kAuthTagUnknown) {
    return args.GetReturnValue().Set(false);
  }

  ArrayBufferOrViewContents<char> auth_tag(args[0]);
  if (UNLIKELY(!auth_tag.CheckSizeInt32()))
    return THROW_ERR_OUT_OF_RANGE(env, "buffer is too big");

  unsigned int tag_len = auth_tag.size();

  const int mode = EVP_CIPHER_CTX_mode(cipher->ctx_.get());
  bool is_valid;
  if (mode == EVP_CIPH_GCM_MODE) {
    // Restrict GCM tag lengths according to NIST 800-38d, page 9.
    is_valid = (cipher->auth_tag_len_ == kNoAuthTagLength ||
                cipher->auth_tag_len_ == tag_len) &&
               IsValidGCMTagLength(tag_len);
  } else {
    // At this point, the tag length is already known and must match the
    // length of the given authentication tag.
    CHECK(IsSupportedAuthenticatedMode(cipher->ctx_.get()));
    CHECK_NE(cipher->auth_tag_len_, kNoAuthTagLength);
    is_valid = cipher->auth_tag_len_ == tag_len;
  }

  if (!is_valid) {
    return THROW_ERR_CRYPTO_INVALID_AUTH_TAG(
      env, "Invalid authentication tag length: %u", tag_len);
  }

  cipher->auth_tag_len_ = tag_len;
  cipher->auth_tag_state_ = kAuthTagKnown;
  CHECK_LE(cipher->auth_tag_len_, sizeof(cipher->auth_tag_));

  memset(cipher->auth_tag_, 0, sizeof(cipher->auth_tag_));
  auth_tag.CopyTo(cipher->auth_tag_, cipher->auth_tag_len_);

  args.GetReturnValue().Set(true);
}

bool CipherBase::MaybePassAuthTagToOpenSSL() {
  if (auth_tag_state_ == kAuthTagKnown) {
    if (!EVP_CIPHER_CTX_ctrl(ctx_.get(),
                             EVP_CTRL_AEAD_SET_TAG,
                             auth_tag_len_,
                             reinterpret_cast<unsigned char*>(auth_tag_))) {
      return false;
    }
    auth_tag_state_ = kAuthTagPassedToOpenSSL;
  }
  return true;
}

bool CipherBase::SetAAD(
    const ArrayBufferOrViewContents<unsigned char>& data,
    int plaintext_len) {
  if (!ctx_ || !IsAuthenticatedMode())
    return false;
  MarkPopErrorOnReturn mark_pop_error_on_return;

  int outlen;
  const int mode = EVP_CIPHER_CTX_mode(ctx_.get());

  // When in CCM mode, we need to set the authentication tag and the plaintext
  // length in advance.
  if (mode == EVP_CIPH_CCM_MODE) {
    if (plaintext_len < 0) {
      THROW_ERR_MISSING_ARGS(env(),
          "options.plaintextLength required for CCM mode with AAD");
      return false;
    }

    if (!CheckCCMMessageLength(plaintext_len))
      return false;

    if (kind_ == kDecipher) {
      if (!MaybePassAuthTagToOpenSSL())
        return false;
    }

    // Specify the plaintext length.
    if (!EVP_CipherUpdate(ctx_.get(), nullptr, &outlen, nullptr, plaintext_len))
      return false;
  }

  return 1 == EVP_CipherUpdate(ctx_.get(),
                               nullptr,
                               &outlen,
                               data.data(),
                               data.size());
}

void CipherBase::SetAAD(const FunctionCallbackInfo<Value>& args) {
  CipherBase* cipher;
  ASSIGN_OR_RETURN_UNWRAP(&cipher, args.Holder());
  Environment* env = Environment::GetCurrent(args);

  CHECK_EQ(args.Length(), 2);
  CHECK(args[1]->IsInt32());
  int plaintext_len = args[1].As<Int32>()->Value();
  ArrayBufferOrViewContents<unsigned char> buf(args[0]);

  if (UNLIKELY(!buf.CheckSizeInt32()))
    return THROW_ERR_OUT_OF_RANGE(env, "buffer is too big");
  args.GetReturnValue().Set(cipher->SetAAD(buf, plaintext_len));
}

CipherBase::UpdateResult CipherBase::Update(
    const char* data,
    size_t len,
    AllocatedBuffer* out) {
  if (!ctx_ || len > INT_MAX)
    return kErrorState;
  MarkPopErrorOnReturn mark_pop_error_on_return;

  const int mode = EVP_CIPHER_CTX_mode(ctx_.get());

  if (mode == EVP_CIPH_CCM_MODE && !CheckCCMMessageLength(len))
    return kErrorMessageSize;

  // Pass the authentication tag to OpenSSL if possible. This will only happen
  // once, usually on the first update.
  if (kind_ == kDecipher && IsAuthenticatedMode())
    CHECK(MaybePassAuthTagToOpenSSL());

  int buf_len = len + EVP_CIPHER_CTX_block_size(ctx_.get());
  // For key wrapping algorithms, get output size by calling
  // EVP_CipherUpdate() with null output.
  if (kind_ == kCipher && mode == EVP_CIPH_WRAP_MODE &&
      EVP_CipherUpdate(ctx_.get(),
                       nullptr,
                       &buf_len,
                       reinterpret_cast<const unsigned char*>(data),
                       len) != 1) {
    return kErrorState;
  }

  *out = AllocatedBuffer::AllocateManaged(env(), buf_len);
  int r = EVP_CipherUpdate(ctx_.get(),
                           reinterpret_cast<unsigned char*>(out->data()),
                           &buf_len,
                           reinterpret_cast<const unsigned char*>(data),
                           len);

  CHECK_LE(static_cast<size_t>(buf_len), out->size());
  out->Resize(buf_len);

  // When in CCM mode, EVP_CipherUpdate will fail if the authentication tag is
  // invalid. In that case, remember the error and throw in final().
  if (!r && kind_ == kDecipher && mode == EVP_CIPH_CCM_MODE) {
    pending_auth_failed_ = true;
    return kSuccess;
  }
  return r == 1 ? kSuccess : kErrorState;
}

void CipherBase::Update(const FunctionCallbackInfo<Value>& args) {
  Decode<CipherBase>(args, [](CipherBase* cipher,
                              const FunctionCallbackInfo<Value>& args,
                              const char* data, size_t size) {
    AllocatedBuffer out;
    Environment* env = Environment::GetCurrent(args);

    if (UNLIKELY(size > INT_MAX))
      return THROW_ERR_OUT_OF_RANGE(env, "data is too long");

    UpdateResult r = cipher->Update(data, size, &out);

    if (r != kSuccess) {
      if (r == kErrorState) {
        ThrowCryptoError(env, ERR_get_error(),
                         "Trying to add data in unsupported state");
      }
      return;
    }

    CHECK(out.data() != nullptr || out.size() == 0);
    args.GetReturnValue().Set(out.ToBuffer().FromMaybe(Local<Value>()));
  });
}

bool CipherBase::SetAutoPadding(bool auto_padding) {
  if (!ctx_)
    return false;
  MarkPopErrorOnReturn mark_pop_error_on_return;
  return EVP_CIPHER_CTX_set_padding(ctx_.get(), auto_padding);
}

void CipherBase::SetAutoPadding(const FunctionCallbackInfo<Value>& args) {
  CipherBase* cipher;
  ASSIGN_OR_RETURN_UNWRAP(&cipher, args.Holder());

  bool b = cipher->SetAutoPadding(args.Length() < 1 || args[0]->IsTrue());
  args.GetReturnValue().Set(b);  // Possibly report invalid state failure
}

bool CipherBase::Final(AllocatedBuffer* out) {
  if (!ctx_)
    return false;

  const int mode = EVP_CIPHER_CTX_mode(ctx_.get());

  *out = AllocatedBuffer::AllocateManaged(
      env(),
      static_cast<size_t>(EVP_CIPHER_CTX_block_size(ctx_.get())));

  if (kind_ == kDecipher && IsSupportedAuthenticatedMode(ctx_.get())) {
    MaybePassAuthTagToOpenSSL();
  }

  // In CCM mode, final() only checks whether authentication failed in update().
  // EVP_CipherFinal_ex must not be called and will fail.
  bool ok;
  if (kind_ == kDecipher && mode == EVP_CIPH_CCM_MODE) {
    ok = !pending_auth_failed_;
    *out = AllocatedBuffer::AllocateManaged(env(), 0);  // Empty buffer.
  } else {
    int out_len = out->size();
    ok = EVP_CipherFinal_ex(ctx_.get(),
                            reinterpret_cast<unsigned char*>(out->data()),
                            &out_len) == 1;

    if (out_len >= 0)
      out->Resize(out_len);
    else
      *out = AllocatedBuffer();  // *out will not be used.

    if (ok && kind_ == kCipher && IsAuthenticatedMode()) {
      // In GCM mode, the authentication tag length can be specified in advance,
      // but defaults to 16 bytes when encrypting. In CCM and OCB mode, it must
      // always be given by the user.
      if (auth_tag_len_ == kNoAuthTagLength) {
        CHECK(mode == EVP_CIPH_GCM_MODE);
        auth_tag_len_ = sizeof(auth_tag_);
      }
      ok = (1 == EVP_CIPHER_CTX_ctrl(ctx_.get(), EVP_CTRL_AEAD_GET_TAG,
                     auth_tag_len_,
                     reinterpret_cast<unsigned char*>(auth_tag_)));
    }
  }

  ctx_.reset();

  return ok;
}

void CipherBase::Final(const FunctionCallbackInfo<Value>& args) {
  Environment* env = Environment::GetCurrent(args);

  CipherBase* cipher;
  ASSIGN_OR_RETURN_UNWRAP(&cipher, args.Holder());
  if (cipher->ctx_ == nullptr)
    return THROW_ERR_CRYPTO_INVALID_STATE(env);

  AllocatedBuffer out;

  // Check IsAuthenticatedMode() first, Final() destroys the EVP_CIPHER_CTX.
  const bool is_auth_mode = cipher->IsAuthenticatedMode();
  bool r = cipher->Final(&out);

  if (!r) {
    const char* msg = is_auth_mode
                          ? "Unsupported state or unable to authenticate data"
                          : "Unsupported state";

    return ThrowCryptoError(env, ERR_get_error(), msg);
  }

  args.GetReturnValue().Set(out.ToBuffer().FromMaybe(Local<Value>()));
}

template <PublicKeyCipher::Operation operation,
          PublicKeyCipher::EVP_PKEY_cipher_init_t EVP_PKEY_cipher_init,
          PublicKeyCipher::EVP_PKEY_cipher_t EVP_PKEY_cipher>
bool PublicKeyCipher::Cipher(
    Environment* env,
    const ManagedEVPPKey& pkey,
    int padding,
    const EVP_MD* digest,
    const ArrayBufferOrViewContents<unsigned char>& oaep_label,
    const ArrayBufferOrViewContents<unsigned char>& data,
    AllocatedBuffer* out) {
  EVPKeyCtxPointer ctx(EVP_PKEY_CTX_new(pkey.get(), nullptr));
  if (!ctx)
    return false;
  if (EVP_PKEY_cipher_init(ctx.get()) <= 0)
    return false;
  if (EVP_PKEY_CTX_set_rsa_padding(ctx.get(), padding) <= 0)
    return false;

  if (digest != nullptr) {
    if (EVP_PKEY_CTX_set_rsa_oaep_md(ctx.get(), digest) <= 0)
      return false;
  }

  if (oaep_label.size() != 0) {
    // OpenSSL takes ownership of the label, so we need to create a copy.
    void* label = OPENSSL_memdup(oaep_label.data(), oaep_label.size());
    CHECK_NOT_NULL(label);
    if (0 >= EVP_PKEY_CTX_set0_rsa_oaep_label(ctx.get(),
                     static_cast<unsigned char*>(label),
                                      oaep_label.size())) {
      OPENSSL_free(label);
      return false;
    }
  }

  size_t out_len = 0;
  if (EVP_PKEY_cipher(
          ctx.get(),
          nullptr,
          &out_len,
          data.data(),
          data.size()) <= 0) {
    return false;
  }

  *out = AllocatedBuffer::AllocateManaged(env, out_len);

  if (EVP_PKEY_cipher(
          ctx.get(),
          reinterpret_cast<unsigned char*>(out->data()),
          &out_len,
          data.data(),
          data.size()) <= 0) {
    return false;
  }

  out->Resize(out_len);
  return true;
}

template <PublicKeyCipher::Operation operation,
          PublicKeyCipher::EVP_PKEY_cipher_init_t EVP_PKEY_cipher_init,
          PublicKeyCipher::EVP_PKEY_cipher_t EVP_PKEY_cipher>
void PublicKeyCipher::Cipher(const FunctionCallbackInfo<Value>& args) {
  MarkPopErrorOnReturn mark_pop_error_on_return;
  Environment* env = Environment::GetCurrent(args);

  unsigned int offset = 0;
  ManagedEVPPKey pkey =
      ManagedEVPPKey::GetPublicOrPrivateKeyFromJs(args, &offset);
  if (!pkey)
    return;

  ArrayBufferOrViewContents<unsigned char> buf(args[offset]);
  if (UNLIKELY(!buf.CheckSizeInt32()))
    return THROW_ERR_OUT_OF_RANGE(env, "buffer is too long");

  uint32_t padding;
  if (!args[offset + 1]->Uint32Value(env->context()).To(&padding)) return;

  const EVP_MD* digest = nullptr;
  if (args[offset + 2]->IsString()) {
    const Utf8Value oaep_str(env->isolate(), args[offset + 2]);
    digest = EVP_get_digestbyname(*oaep_str);
    if (digest == nullptr)
      return THROW_ERR_OSSL_EVP_INVALID_DIGEST(env);
  }

  ArrayBufferOrViewContents<unsigned char> oaep_label;
  if (!args[offset + 3]->IsUndefined()) {
    oaep_label = ArrayBufferOrViewContents<unsigned char>(args[offset + 3]);
    if (UNLIKELY(!oaep_label.CheckSizeInt32()))
      return THROW_ERR_OUT_OF_RANGE(env, "oaep_label is too big");
  }

  AllocatedBuffer out;
  if (!Cipher<operation, EVP_PKEY_cipher_init, EVP_PKEY_cipher>(
          env, pkey, padding, digest, oaep_label, buf, &out)) {
    return ThrowCryptoError(env, ERR_get_error());
  }

  Local<Value> result;
  if (out.ToBuffer().ToLocal(&result))
    args.GetReturnValue().Set(result);
}

}  // namespace crypto
}  // namespace node

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