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crypto: deduplicate cipher initialization code
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CipherBase::Init and CipherBase::InitIv contain a lot of duplicate
code, this commit moves that into a separate function.

PR-URL: #23011
Reviewed-By: Anna Henningsen <anna@addaleax.net>
Reviewed-By: Ben Noordhuis <info@bnoordhuis.nl>
Reviewed-By: James M Snell <jasnell@gmail.com>
Reviewed-By: Ujjwal Sharma <usharma1998@gmail.com>
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@tniessen @targos
tniessen authored and targos committed Sep 27, 2018
1 parent c54e423 commit 2888f80
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Showing 2 changed files with 64 additions and 77 deletions.
130 changes: 55 additions & 75 deletions src/node_crypto.cc
View file
Original file line number Diff line number Diff line change
Expand Up @@ -2539,6 +2539,12 @@ int VerifyCallback(int preverify_ok, X509_STORE_CTX* ctx) {
return 1;
}

static bool IsSupportedAuthenticatedMode(int mode) {
return mode == EVP_CIPH_CCM_MODE ||
mode == EVP_CIPH_GCM_MODE ||
mode == EVP_CIPH_OCB_MODE;
}

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

Expand All @@ -2565,6 +2571,43 @@ void CipherBase::New(const FunctionCallbackInfo<Value>& args) {
new CipherBase(env, args.This(), kind);
}

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(mode)) {
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 env()->ThrowError("Invalid key length");
}

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 char* key_buf,
Expand All @@ -2580,7 +2623,6 @@ void CipherBase::Init(const char* cipher_type,
}
#endif // NODE_FIPS_MODE

CHECK(!ctx_);
const EVP_CIPHER* const cipher = EVP_get_cipherbyname(cipher_type);
if (cipher == nullptr)
return env()->ThrowError("Unknown cipher");
Expand All @@ -2598,45 +2640,19 @@ void CipherBase::Init(const char* cipher_type,
iv);
CHECK_NE(key_len, 0);

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 (encrypt && (mode == EVP_CIPH_CTR_MODE || mode == EVP_CIPH_GCM_MODE ||
mode == EVP_CIPH_CCM_MODE)) {
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);
}

if (IsAuthenticatedMode()) {
if (!InitAuthenticated(cipher_type, EVP_CIPHER_iv_length(cipher),
auth_tag_len))
return;
}

CHECK_EQ(1, EVP_CIPHER_CTX_set_key_length(ctx_.get(), key_len));

if (1 != EVP_CipherInit_ex(ctx_.get(),
nullptr,
nullptr,
reinterpret_cast<unsigned char*>(key),
reinterpret_cast<unsigned char*>(iv),
encrypt)) {
return ThrowCryptoError(env(), ERR_get_error(),
"Failed to initialize cipher");
}
CommonInit(cipher_type, cipher, key, key_len, iv,
EVP_CIPHER_iv_length(cipher), auth_tag_len);
}


Expand All @@ -2663,16 +2679,10 @@ void CipherBase::Init(const FunctionCallbackInfo<Value>& args) {
cipher->Init(*cipher_type, key_buf, key_buf_len, auth_tag_len);
}

static bool IsSupportedAuthenticatedMode(int mode) {
return mode == EVP_CIPH_CCM_MODE ||
mode == EVP_CIPH_GCM_MODE ||
mode == EVP_CIPH_OCB_MODE;
}

void CipherBase::InitIv(const char* cipher_type,
const char* key,
const unsigned char* key,
int key_len,
const char* iv,
const unsigned char* iv,
int iv_len,
unsigned int auth_tag_len) {
HandleScope scope(env()->isolate());
Expand Down Expand Up @@ -2700,38 +2710,7 @@ void CipherBase::InitIv(const char* cipher_type,
return env()->ThrowError("Invalid IV length");
}

ctx_.reset(EVP_CIPHER_CTX_new());

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 (is_authenticated_mode) {
CHECK(has_iv);
if (!InitAuthenticated(cipher_type, iv_len, auth_tag_len))
return;
}

if (!EVP_CIPHER_CTX_set_key_length(ctx_.get(), key_len)) {
ctx_.reset();
return env()->ThrowError("Invalid key length");
}

if (1 != EVP_CipherInit_ex(ctx_.get(),
nullptr,
nullptr,
reinterpret_cast<const unsigned char*>(key),
reinterpret_cast<const unsigned char*>(iv),
encrypt)) {
return ThrowCryptoError(env(), ERR_get_error(),
"Failed to initialize cipher");
}
CommonInit(cipher_type, cipher, key, key_len, iv, iv_len, auth_tag_len);
}


Expand All @@ -2744,14 +2723,15 @@ void CipherBase::InitIv(const FunctionCallbackInfo<Value>& args) {

const node::Utf8Value cipher_type(env->isolate(), args[0]);
ssize_t key_len = Buffer::Length(args[1]);
const char* key_buf = Buffer::Data(args[1]);
const unsigned char* key_buf = reinterpret_cast<unsigned char*>(
Buffer::Data(args[1]));
ssize_t iv_len;
const char* iv_buf;
const unsigned char* iv_buf;
if (args[2]->IsNull()) {
iv_buf = nullptr;
iv_len = -1;
} else {
iv_buf = Buffer::Data(args[2]);
iv_buf = reinterpret_cast<unsigned char*>(Buffer::Data(args[2]));
iv_len = Buffer::Length(args[2]);
}

Expand Down
11 changes: 9 additions & 2 deletions src/node_crypto.h
View file
Original file line number Diff line number Diff line change
Expand Up @@ -370,14 +370,21 @@ class CipherBase : public BaseObject {
};
static const unsigned kNoAuthTagLength = static_cast<unsigned>(-1);

void 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);
void Init(const char* cipher_type,
const char* key_buf,
int key_buf_len,
unsigned int auth_tag_len);
void InitIv(const char* cipher_type,
const char* key,
const unsigned char* key,
int key_len,
const char* iv,
const unsigned char* iv,
int iv_len,
unsigned int auth_tag_len);
bool InitAuthenticated(const char* cipher_type, int iv_len,
Expand Down

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