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src: remove extra heap allocations in DH functions
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Replace allocate + Encode() + free patterns by calls to Malloc +
the Buffer::New() overload that takes ownership of the pointer.
Avoids unnecessary heap allocations and copying around of data.

DRY the accessor functions for the prime, generator, public key and
private key properties; deletes about 40 lines of quadruplicated code.

PR-URL: #14122
Reviewed-By: Anna Henningsen <anna@addaleax.net>
Reviewed-By: James M Snell <jasnell@gmail.com>
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@bnoordhuis @addaleax
bnoordhuis authored and addaleax committed Jul 18, 2017
1 parent 8e51d31 commit 233740c
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Showing 2 changed files with 31 additions and 77 deletions.
106 changes: 29 additions & 77 deletions src/node_crypto.cc
View file
Original file line number Diff line number Diff line change
Expand Up @@ -4762,99 +4762,49 @@ void DiffieHellman::GenerateKeys(const FunctionCallbackInfo<Value>& args) {
return ThrowCryptoError(env, ERR_get_error(), "Key generation failed");
}

int dataSize = BN_num_bytes(diffieHellman->dh->pub_key);
char* data = new char[dataSize];
BN_bn2bin(diffieHellman->dh->pub_key,
reinterpret_cast<unsigned char*>(data));

args.GetReturnValue().Set(Encode(env->isolate(), data, dataSize, BUFFER));
delete[] data;
size_t size = BN_num_bytes(diffieHellman->dh->pub_key);
char* data = Malloc(size);
BN_bn2bin(diffieHellman->dh->pub_key, reinterpret_cast<unsigned char*>(data));
args.GetReturnValue().Set(Buffer::New(env, data, size).ToLocalChecked());
}


void DiffieHellman::GetPrime(const FunctionCallbackInfo<Value>& args) {
void DiffieHellman::GetField(const FunctionCallbackInfo<Value>& args,
BIGNUM* (DH::*field), const char* err_if_null) {
Environment* env = Environment::GetCurrent(args);

DiffieHellman* diffieHellman;
ASSIGN_OR_RETURN_UNWRAP(&diffieHellman, args.Holder());
DiffieHellman* dh;
ASSIGN_OR_RETURN_UNWRAP(&dh, args.Holder());
if (!dh->initialised_) return env->ThrowError("Not initialized");

if (!diffieHellman->initialised_) {
return ThrowCryptoError(env, ERR_get_error(), "Not initialized");
}
const BIGNUM* num = (dh->dh)->*field;
if (num == nullptr) return env->ThrowError(err_if_null);

int dataSize = BN_num_bytes(diffieHellman->dh->p);
char* data = new char[dataSize];
BN_bn2bin(diffieHellman->dh->p, reinterpret_cast<unsigned char*>(data));
size_t size = BN_num_bytes(num);
char* data = Malloc(size);
BN_bn2bin(num, reinterpret_cast<unsigned char*>(data));
args.GetReturnValue().Set(Buffer::New(env, data, size).ToLocalChecked());
}

args.GetReturnValue().Set(Encode(env->isolate(), data, dataSize, BUFFER));
delete[] data;
void DiffieHellman::GetPrime(const FunctionCallbackInfo<Value>& args) {
GetField(args, &DH::p, "p is null");
}


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

DiffieHellman* diffieHellman;
ASSIGN_OR_RETURN_UNWRAP(&diffieHellman, args.Holder());

if (!diffieHellman->initialised_) {
return ThrowCryptoError(env, ERR_get_error(), "Not initialized");
}

int dataSize = BN_num_bytes(diffieHellman->dh->g);
char* data = new char[dataSize];
BN_bn2bin(diffieHellman->dh->g, reinterpret_cast<unsigned char*>(data));

args.GetReturnValue().Set(Encode(env->isolate(), data, dataSize, BUFFER));
delete[] data;
GetField(args, &DH::g, "g is null");
}


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

DiffieHellman* diffieHellman;
ASSIGN_OR_RETURN_UNWRAP(&diffieHellman, args.Holder());

if (!diffieHellman->initialised_) {
return ThrowCryptoError(env, ERR_get_error(), "Not initialized");
}

if (diffieHellman->dh->pub_key == nullptr) {
return env->ThrowError("No public key - did you forget to generate one?");
}

int dataSize = BN_num_bytes(diffieHellman->dh->pub_key);
char* data = new char[dataSize];
BN_bn2bin(diffieHellman->dh->pub_key,
reinterpret_cast<unsigned char*>(data));

args.GetReturnValue().Set(Encode(env->isolate(), data, dataSize, BUFFER));
delete[] data;
GetField(args, &DH::pub_key,
"No public key - did you forget to generate one?");
}


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

DiffieHellman* diffieHellman;
ASSIGN_OR_RETURN_UNWRAP(&diffieHellman, args.Holder());

if (!diffieHellman->initialised_) {
return ThrowCryptoError(env, ERR_get_error(), "Not initialized");
}

if (diffieHellman->dh->priv_key == nullptr) {
return env->ThrowError("No private key - did you forget to generate one?");
}

int dataSize = BN_num_bytes(diffieHellman->dh->priv_key);
char* data = new char[dataSize];
BN_bn2bin(diffieHellman->dh->priv_key,
reinterpret_cast<unsigned char*>(data));

args.GetReturnValue().Set(Encode(env->isolate(), data, dataSize, BUFFER));
delete[] data;
GetField(args, &DH::priv_key,
"No private key - did you forget to generate one?");
}


Expand Down Expand Up @@ -4882,7 +4832,7 @@ void DiffieHellman::ComputeSecret(const FunctionCallbackInfo<Value>& args) {
}

int dataSize = DH_size(diffieHellman->dh);
char* data = new char[dataSize];
char* data = Malloc(dataSize);

int size = DH_compute_key(reinterpret_cast<unsigned char*>(data),
key,
Expand All @@ -4894,7 +4844,7 @@ void DiffieHellman::ComputeSecret(const FunctionCallbackInfo<Value>& args) {

checked = DH_check_pub_key(diffieHellman->dh, key, &checkResult);
BN_free(key);
delete[] data;
free(data);

if (!checked) {
return ThrowCryptoError(env, ERR_get_error(), "Invalid Key");
Expand All @@ -4909,6 +4859,8 @@ void DiffieHellman::ComputeSecret(const FunctionCallbackInfo<Value>& args) {
} else {
return env->ThrowError("Invalid key");
}

UNREACHABLE();
}

BN_free(key);
Expand All @@ -4924,8 +4876,8 @@ void DiffieHellman::ComputeSecret(const FunctionCallbackInfo<Value>& args) {
memset(data, 0, dataSize - size);
}

args.GetReturnValue().Set(Encode(env->isolate(), data, dataSize, BUFFER));
delete[] data;
auto rc = Buffer::New(env->isolate(), data, dataSize).ToLocalChecked();
args.GetReturnValue().Set(rc);
}


Expand Down
2 changes: 2 additions & 0 deletions src/node_crypto.h
View file
Original file line number Diff line number Diff line change
Expand Up @@ -690,6 +690,8 @@ class DiffieHellman : public BaseObject {
}

private:
static void GetField(const v8::FunctionCallbackInfo<v8::Value>& args,
BIGNUM* (DH::*field), const char* err_if_null);
bool VerifyContext();

bool initialised_;
Expand Down

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