Initial commit

1 files changed, 200 insertions, 0 deletions

diff --git a/crypto.cpp b/crypto.cpp
new file mode 100644
index 0000000..818f68a
--- /dev/null
+++ b/crypto.cpp
@@ -0,0 +1,200 @@
+extern "C" {
+#include <openssl/evp.h>
+#include <openssl/hmac.h>
+#include <openssl/aes.h>
+#include <openssl/rand.h>
+}
+
+#include "totpgen.h"
+
+#define UNUSED(x) (void(x))
+
+#define SALT_BYTES 8
+#define KEY_BYTES  32
+#define IV_BYTES   16
+
+
+#define AES_BUFFER(LEN) \
+	reinterpret_cast<unsigned char *>( \
+		calloc(AES_BLOCK_SIZE * (1 + ((LEN) / AES_BLOCK_SIZE)), \
+			sizeof(unsigned char)));
+
+bool
+TOTPGen::GenTOTP(std::string& secret_str)
+{
+	uint32_t bits, code, count, hmacsize;
+	uint64_t clock;
+	size_t length;
+	uint8_t msg[8], hmac[EVP_MAX_MD_SIZE];
+	char totp_buf[7];
+
+	size_t keysize = 0;
+	const EVP_MD *digest = EVP_sha1();
+	uint8_t *key = NULL;
+
+	char *secret = strdup(secret_str.c_str());
+
+	for (count = bits = length = 0; *secret; secret++) {
+		if (!strchr(base32.c_str(), *secret)) {
+			return false;
+		}
+		bits = (bits << 5) | (strchr(base32.c_str(), *secret) - base32.c_str());
+		count += 5;
+
+		while (count >= 8) {
+			while (length >= keysize) {
+				keysize = keysize ? keysize << 1 : 64;
+				if (!(key = (uint8_t *)realloc(key, keysize))) {
+					return false;
+				}
+			}
+			count -= 8, key[length++] = bits >> count;
+		}
+	}
+
+	if (length > 0) {
+		clock = time(NULL) / 30;
+
+		for (count = 0; count < 8; count++) {
+			msg[7 - count] = clock >> 8 * count;
+		}
+		if (!HMAC(digest, key, length, msg, sizeof(msg), hmac, &hmacsize)) {
+			return false;
+		}
+
+		for (code = count = 0; count < 4; count++) {
+			code += hmac[(hmac[hmacsize - 1] & 0x0f) + 3 - count] << 8 * count;
+		}
+		code &= 0x7fffffff;
+
+		snprintf((char *)&totp_buf, 7, "%06u", code % 1000000);
+	}
+	else {
+		return false;
+	}
+
+	TOTP = totp_buf;
+	TOTPField->SetLabel(TOTP);
+
+	free(key);
+
+	return true;
+}
+
+void
+TOTPGen::InitAES(const char *passphrase, unsigned char *salt,
+                 unsigned char *key, unsigned char *iv)
+{
+	char *key_data = strdup(passphrase);
+	int key_text_len = strlen(passphrase);
+	int nrounds = 0xFF;
+
+	EVP_BytesToKey(EVP_aes_256_cbc(), EVP_sha1(), salt,
+	               reinterpret_cast<unsigned char *>(key_data),
+	               key_text_len, nrounds, key, iv);
+
+	free(key_data);
+}
+
+bool
+TOTPGen::EncryptSecret(std::string& secret_str)
+{
+	unsigned char salt[SALT_BYTES], key[KEY_BYTES], iv[IV_BYTES];
+
+	RAND_bytes(salt, SALT_BYTES);
+
+	memset(&key, 0, KEY_BYTES);
+	memset(&iv, 0, IV_BYTES);
+
+	InitAES(Passphrase.c_str(), reinterpret_cast<unsigned char *>(&salt),
+	        reinterpret_cast<unsigned char *>(&key),
+	        reinterpret_cast<unsigned char *>(&iv));
+
+	EVP_CIPHER_CTX *ctx = EVP_CIPHER_CTX_new();
+	EVP_EncryptInit_ex(ctx, EVP_aes_256_cbc(), NULL,
+	                   reinterpret_cast<unsigned char *>(&key),
+	                   reinterpret_cast<unsigned char *>(&iv));
+
+	size_t plaintext_len = strlen(secret_str.c_str()) ;
+
+	unsigned char *plaintext = AES_BUFFER(plaintext_len);
+	strncpy(reinterpret_cast<char *>(plaintext),
+	        secret_str.c_str(), plaintext_len);
+
+	unsigned char *ciphertext = AES_BUFFER(plaintext_len);
+
+	int len, ciphertext_len;
+	EVP_EncryptUpdate(ctx, ciphertext, &len, plaintext, plaintext_len);
+	ciphertext_len = len;
+	EVP_EncryptFinal_ex(ctx, ciphertext + len, &len);
+	ciphertext_len += len;
+
+	FILE *secret_file = fopen(SecretFile.c_str(), "wb");
+	if (!secret_file) {
+		return false;
+	}
+
+	fwrite(salt, SALT_BYTES, 1, secret_file);
+	fwrite(ciphertext, ciphertext_len, 1, secret_file);
+
+	fclose(secret_file);
+
+	EVP_CIPHER_CTX_free(ctx);
+	free(plaintext);
+	free(ciphertext);
+
+	return true;
+}
+
+
+bool
+TOTPGen::DecryptSecret(void)
+{
+	unsigned char salt[SALT_BYTES], key[KEY_BYTES], iv[IV_BYTES];
+
+	memset(&key, 0, KEY_BYTES);
+	memset(&iv, 0, IV_BYTES);
+
+	FILE *secret_file = fopen(SecretFile.c_str(), "rb");
+	if (!secret_file) {
+		return false;
+	}
+
+	fseek(secret_file, 0L, SEEK_END);
+	size_t ciphertext_len = ftell(secret_file) - SALT_BYTES;
+	rewind(secret_file);
+
+	fread(&salt, SALT_BYTES, 1, secret_file);
+
+	InitAES(Passphrase.c_str(), reinterpret_cast<unsigned char *>(&salt),
+	        reinterpret_cast<unsigned char *>(&key),
+	        reinterpret_cast<unsigned char *>(&iv));
+
+	EVP_CIPHER_CTX *ctx = EVP_CIPHER_CTX_new();
+	EVP_DecryptInit_ex(ctx, EVP_aes_256_cbc(), NULL,
+	                   reinterpret_cast<unsigned char *>(&key),
+	                   reinterpret_cast<unsigned char *>(&iv));
+
+	int len;
+	unsigned char *ciphertext = AES_BUFFER(ciphertext_len);
+	unsigned char *plaintext = AES_BUFFER(ciphertext_len + 8);
+
+	fread(ciphertext, 1, ciphertext_len, secret_file);
+	fclose(secret_file);
+
+	if (!EVP_DecryptUpdate(ctx, plaintext, &len, ciphertext, ciphertext_len)) {
+		return false;
+	}
+
+	if (!EVP_DecryptFinal_ex(ctx, plaintext + len, &len)) {
+		return false;
+	}
+
+	Secret = reinterpret_cast<const char *>(plaintext);
+
+	EVP_CIPHER_CTX_free(ctx);
+	free(ciphertext);
+	free(plaintext);
+
+	return true;
+}