crypto: harden bignum-to-binary conversions

PR-URL: https://github.com/nodejs/node/pull/24719
Refs: https://github.com/nodejs/node/issues/24645
Reviewed-By: Colin Ihrig <cjihrig@gmail.com>
Reviewed-By: James M Snell <jasnell@gmail.com>
This commit is contained in:
Ben Noordhuis 2018-11-29 11:09:12 +01:00 committed by Daniel Bevenius
parent 5b90902b8b
commit 3513b0c3d9

View File

@ -4211,9 +4211,11 @@ void DiffieHellman::GenerateKeys(const FunctionCallbackInfo<Value>& args) {
const BIGNUM* pub_key;
DH_get0_key(diffieHellman->dh_.get(), &pub_key, nullptr);
size_t size = BN_num_bytes(pub_key);
const int size = BN_num_bytes(pub_key);
CHECK_GE(size, 0);
char* data = Malloc(size);
BN_bn2bin(pub_key, reinterpret_cast<unsigned char*>(data));
CHECK_EQ(size,
BN_bn2binpad(pub_key, reinterpret_cast<unsigned char*>(data), size));
args.GetReturnValue().Set(Buffer::New(env, data, size).ToLocalChecked());
}
@ -4229,9 +4231,11 @@ void DiffieHellman::GetField(const FunctionCallbackInfo<Value>& args,
const BIGNUM* num = get_field(dh->dh_.get());
if (num == nullptr) return env->ThrowError(err_if_null);
size_t size = BN_num_bytes(num);
const int size = BN_num_bytes(num);
CHECK_GE(size, 0);
char* data = Malloc(size);
BN_bn2bin(num, reinterpret_cast<unsigned char*>(data));
CHECK_EQ(size,
BN_bn2binpad(num, reinterpret_cast<unsigned char*>(data), size));
args.GetReturnValue().Set(Buffer::New(env, data, size).ToLocalChecked());
}
@ -4567,13 +4571,9 @@ void ECDH::GetPrivateKey(const FunctionCallbackInfo<Value>& args) {
if (b == nullptr)
return env->ThrowError("Failed to get ECDH private key");
int size = BN_num_bytes(b);
const int size = BN_num_bytes(b);
unsigned char* out = node::Malloc<unsigned char>(size);
if (size != BN_bn2bin(b, out)) {
free(out);
return env->ThrowError("Failed to convert ECDH private key to Buffer");
}
CHECK_EQ(size, BN_bn2binpad(b, out, size));
Local<Object> buf =
Buffer::New(env, reinterpret_cast<char*>(out), size).ToLocalChecked();