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[CSE] Add a DecryptAsync method

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Also, cleanup a bit of the old calls. One particular difference
is that I used to set padding to 1 and it should actually be
PKCS1_OAEP_PADDING
This commit is contained in:
Tomaz Canabrava 2017-12-12 21:23:02 +01:00
parent aca298ca64
commit 159c0e138f
1 changed files with 70 additions and 63 deletions
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133
src/libsync/clientsideencryption.cpp
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@ -83,10 +83,17 @@ public:
const QByteArray& key,
const QByteArray& data
);
//TODO: change those two EVP_PKEY into QSslKey.
static QByteArray encryptStringAsymmetric(
EVP_PKEY *publicKey,
const QByteArray& data
);
static QByteArray decryptStringAsymmetric(
EVP_PKEY *privateKey,
const QByteArray& data
);
static QByteArray BIO2ByteArray(BIO *b);
};
@ -467,6 +474,65 @@ QByteArray EncryptionHelper::encryptStringSymmetric(const QByteArray& key, const
return result;
}
QByteArray EncryptionHelper::decryptStringAsymmetric(EVP_PKEY *privateKey, const QByteArray& data) {
int err = -1;
auto ctx = EVP_PKEY_CTX_new(privateKey, ENGINE_get_default_RSA());
if (!ctx) {
qCInfo(lcCse()) << "Could not create the PKEY context.";
exit(1);
}
err = EVP_PKEY_decrypt_init(ctx);
if (err <= 0) {
qCInfo(lcCse()) << "Could not init the decryption of the metadata";
exit(1);
}
if (EVP_PKEY_CTX_set_rsa_padding(ctx, RSA_PKCS1_OAEP_PADDING) <= 0) {
qCInfo(lcCse()) << "Error setting the encryption padding.";
exit(1);
}
if (EVP_PKEY_CTX_set_rsa_oaep_md(ctx, EVP_sha256()) <= 0) {
qCInfo(lcCse()) << "Error setting OAEP SHA 256";
exit(1);
}
if (EVP_PKEY_CTX_set_rsa_mgf1_md(ctx, EVP_sha256()) <= 0) {
qCInfo(lcCse()) << "Error setting MGF1 padding";
exit(1);
}
size_t outlen = 0;
err = EVP_PKEY_decrypt(ctx, NULL, &outlen, (unsigned char *)data.constData(), data.size());
if (err <= 0) {
qCInfo(lcCse()) << "Could not determine the buffer length";
exit(1);
} else {
qCInfo(lcCse()) << "Size of output is: " << outlen;
}
unsigned char *out = (unsigned char *) OPENSSL_malloc(outlen);
if (!out) {
qCInfo(lcCse()) << "Could not alloc space for the decrypted metadata";
exit(1);
}
if (EVP_PKEY_decrypt(ctx, out, &outlen, (unsigned char *)data.constData(), data.size()) <= 0) {
qCInfo(lcCse()) << "Could not decrypt the metadata";
exit(1);
}
qCInfo(lcCse()) << "Metadata decrypted successfully";
const auto ret = std::string((char*) out, outlen);
// Transform the encrypted data into base64.
QByteArray raw((const char*) out, outlen);
qCInfo(lcCse()) << raw;
return raw;
}
QByteArray EncryptionHelper::encryptStringAsymmetric(EVP_PKEY *publicKey, const QByteArray& data) {
int err = -1;
@ -1065,7 +1131,6 @@ QByteArray FolderMetadata::encryptMetadataKeys(const nlohmann::json& metadataKey
BIO *publicKeyBio = BIO_new(BIO_s_mem());
QByteArray publicKeyPem = _account->e2e()->_publicKey.toPem();
BIO_write(publicKeyBio, publicKeyPem.constData(), publicKeyPem.size());
EVP_PKEY *publicKey = PEM_read_bio_PUBKEY(publicKeyBio, NULL, NULL, NULL);
auto data = QByteArray::fromStdString(metadataKeys.dump());
@ -1076,75 +1141,17 @@ QByteArray FolderMetadata::encryptMetadataKeys(const nlohmann::json& metadataKey
return ret;
}
//TODO: Change this from std::string to QByteArray.
std::string FolderMetadata::decryptMetadataKeys(const std::string& encryptedMetadata) const
{
qCInfo(lcCse()) << "Starting to decrypt the metadata key";
unsigned char *out = nullptr;
size_t outlen = 0;
int err = -1;
BIO *privateKeyBio = BIO_new(BIO_s_mem());
QByteArray privateKeyPem = _account->e2e()->_privateKey.toPem();
BIO_write(privateKeyBio, privateKeyPem.constData(), privateKeyPem.size());
EVP_PKEY *key = PEM_read_bio_PrivateKey(privateKeyBio, NULL, NULL, NULL);
if (!key) {
qCInfo(lcCse()) << "Error reading private key";
}
// Data is base64 encoded.
qCInfo(lcCse()) << "encryptedMetadata" << encryptedMetadata;
auto raw = QByteArray(encryptedMetadata.c_str(), encryptedMetadata.length());
auto b64d = QByteArray::fromBase64(raw);
auto in = (unsigned char *) b64d.constData();
size_t inlen = b64d.length();
qCInfo(lcCse()) << "Encrypted metadata length: " << inlen;
/* NB: assumes key in, inlen are already set up
* and that key is an RSA private key
*/
auto ctx = EVP_PKEY_CTX_new(key, nullptr);
if (!ctx) {
qCInfo(lcCse()) << "Could not create the PKEY context.";
exit(1);
}
err = EVP_PKEY_decrypt_init(ctx);
if (err <= 0) {
qCInfo(lcCse()) << "Could not init the decryption of the metadata";
exit(1);
}
err = EVP_PKEY_CTX_set_rsa_padding(ctx, 1); //TODO: Make this a class variable.
if (err <= 0) {
qCInfo(lcCse()) << "Could not set the RSA padding";
exit(1);
}
err = EVP_PKEY_decrypt(ctx, NULL, &outlen, in, inlen);
if (err <= 0) {
qCInfo(lcCse()) << "Could not determine the buffer length";
exit(1);
} else {
qCInfo(lcCse()) << "Size of output is: " << outlen;
}
out = (unsigned char *) OPENSSL_malloc(outlen);
if (!out) {
qCInfo(lcCse()) << "Could not alloc space for the decrypted metadata";
exit(1);
}
err = EVP_PKEY_decrypt(ctx, out, &outlen, in, inlen);
if (err <= 0) {
qCInfo(lcCse()) << "Could not decrypt the metadata";
exit(1);
}
qCInfo(lcCse()) << "Metadata decrypted successfully";
const auto ret = std::string((char*) out, outlen);
auto data = QByteArray::fromStdString(encryptedMetadata);
auto decryptedData = EncryptionHelper::decryptStringAsymmetric(key, data);
std::string ret(decryptedData.constData(), decryptedData.length());
return ret;
}