1 files changed, 102 insertions, 0 deletions
diff --git a/src/crypto.cc b/src/crypto.cc
new file mode 100644
index 0000000..8be90fd
--- /dev/null
+++ b/src/crypto.cc
@@ -0,0 +1,102 @@
+#include "login.hh"
+
+#include <openssl/err.h>
+#include <openssl/rsa.h>
+#include <openssl/pem.h>
+
+static void DumpOpenSSLErrors(const char *Where, const char *What){
+	LOG_ERR("OpenSSL error(s) while executing %s at %s:", What, Where);
+	ERR_print_errors_cb(
+		[](const char *str, usize len, void *u) -> int {
+			// NOTE(fusion): These error strings already have trailing newlines,
+			// for whatever reason.
+			if(len > 0 && str[len - 1] == '\n'){
+				len -= 1;
+			}
+
+			if(len > 0){
+				LOG_ERR("> %*s", (int)len, str);
+			}
+
+			return 1;
+		}, NULL);
+}
+
+RSAKey *RSALoadPEM(const char *FileName){
+	FILE *File = fopen(FileName, "rb");
+	if(File == NULL){
+		LOG_ERR("Failed to open \"%s\"", FileName);
+		return NULL;
+	}
+
+	RSA *Key = PEM_read_RSAPrivateKey(File, NULL, NULL, NULL);
+	fclose(File);
+	if(Key == NULL){
+		LOG_ERR("Failed to read key from \"%s\"", FileName);
+		DumpOpenSSLErrors("RSALoadPem", "PEM_read_PrivateKey");
+	}
+
+	return (RSAKey*)Key;
+}
+
+void RSAFree(RSAKey *Key){
+	RSA_free((RSA*)Key);
+}
+
+bool RSADecrypt(RSAKey *Key, uint8 *Data, int Size){
+	ASSERT(Data != NULL && Size > 0);
+	if(Key == NULL){
+		LOG_ERR("Key not initialized");
+		return false;
+	}
+
+	if(Size != RSA_size((RSA*)Key)){
+		LOG_ERR("Invalid data size %d (expected %d)", Size, RSA_size((RSA*)Key));
+		return false;
+	}
+
+	if(RSA_private_decrypt(Size, Data, Data, (RSA*)Key, RSA_NO_PADDING) == -1){
+		DumpOpenSSLErrors("RSADecrypt", "RSA_private_decrypt");
+		return false;
+	}
+
+	return true;
+}
+
+void XTEAEncrypt(const uint32 *Key, uint8 *Data, int Size){
+	ASSERT(Key != NULL);
+	while(Size >= 8){
+		uint32 Sum = 0x00000000UL;
+		uint32 Delta = 0x9E3779B9UL;
+		uint32 V0 = BufferRead32LE(&Data[0]);
+		uint32 V1 = BufferRead32LE(&Data[4]);
+		for(int i = 0; i < 32; i += 1){
+			V0 += (((V1 << 4) ^ (V1 >> 5)) + V1) ^ (Sum + Key[Sum & 3]);
+			Sum += Delta;
+			V1 += (((V0 << 4) ^ (V0 >> 5)) + V0) ^ (Sum + Key[(Sum >> 11) & 3]);
+		}
+		BufferWrite32LE(&Data[0], V0);
+		BufferWrite32LE(&Data[4], V1);
+		Data += 8;
+		Size -= 8;
+	}
+}
+
+void XTEADecrypt(const uint32 *Key, uint8 *Data, int Size){
+	ASSERT(Key != NULL);
+	while(Size >= 8){
+		uint32 Sum = 0xC6EF3720UL;
+		uint32 Delta = 0x9E3779B9UL;
+		uint32 V0 = BufferRead32LE(&Data[0]);
+		uint32 V1 = BufferRead32LE(&Data[4]);
+		for(int i = 0; i < 32; i += 1){
+			V1 -= (((V0 << 4) ^ (V0 >> 5)) + V0) ^ (Sum + Key[(Sum >> 11) & 3]);
+			Sum -= Delta;
+			V0 -= (((V1 << 4) ^ (V1 >> 5)) + V1) ^ (Sum + Key[Sum & 3]);
+		}
+		BufferWrite32LE(&Data[0], V0);
+		BufferWrite32LE(&Data[4], V1);
+		Data += 8;
+		Size -= 8;
+	}
+}