Convert aes128-gcm into a generic gcm method

7 files changed, 51 insertions, 29 deletions

diff --git a/src/methods/CMakeLists.txt b/src/methods/CMakeLists.txt
index c5a6273..d707884 100644
--- a/src/methods/CMakeLists.txt
+++ b/src/methods/CMakeLists.txt
@@ -6,10 +6,10 @@ if(WITH_METHOD_XSALSA20_POLY1305)
   set(METHOD_COMMON TRUE)
 endif(WITH_METHOD_XSALSA20_POLY1305)
 
-if(WITH_METHOD_AES128_GCM)
-  list(APPEND METHODS aes128_gcm)
+if(WITH_METHOD_GENERIC_GCM)
+  list(APPEND METHODS generic_gcm)
   set(METHOD_COMMON TRUE)
-endif(WITH_METHOD_AES128_GCM)
+endif(WITH_METHOD_GENERIC_GCM)
 
 
 set(METHOD_SOURCES "${CMAKE_CURRENT_BINARY_DIR}/methods.c")
diff --git a/src/methods/aes128_gcm/CMakeLists.txt b/src/methods/aes128_gcm/CMakeLists.txt
deleted file mode 100644
index 6d07318..0000000
--- a/src/methods/aes128_gcm/CMakeLists.txt
+++ /dev/null
@@ -1,6 +0,0 @@
-include_directories(${FASTD_SOURCE_DIR}/src ${FASTD_BINARY_DIR} ${NACL_INCLUDE_DIRS})
-
-add_library(method_aes128_gcm OBJECT
-  aes128_gcm.c
-)
-set_property(TARGET method_aes128_gcm PROPERTY COMPILE_FLAGS "${FASTD_CFLAGS}")
diff --git a/src/methods/generic_gcm/CMakeLists.txt b/src/methods/generic_gcm/CMakeLists.txt
new file mode 100644
index 0000000..1771ee0
--- /dev/null
+++ b/src/methods/generic_gcm/CMakeLists.txt
@@ -0,0 +1,6 @@
+include_directories(${FASTD_SOURCE_DIR}/src ${FASTD_BINARY_DIR})
+
+add_library(method_generic_gcm OBJECT
+  generic_gcm.c
+)
+set_property(TARGET method_generic_gcm PROPERTY COMPILE_FLAGS "${FASTD_CFLAGS}")
diff --git a/src/methods/aes128_gcm/aes128_gcm.c b/src/methods/generic_gcm/generic_gcm.c
index 8a6325e..479ea83 100644
--- a/src/methods/aes128_gcm/aes128_gcm.c
+++ b/src/methods/generic_gcm/generic_gcm.c
@@ -32,16 +32,39 @@
 struct fastd_method_session_state {
 	fastd_method_common_t common;
 
-	const fastd_cipher_t *aes128_ctr;
-	fastd_cipher_context_t *aes128_ctr_ctx;
-	fastd_cipher_state_t *aes128_ctr_state;
+	const fastd_cipher_t *cipher;
+	fastd_cipher_context_t *cipher_ctx;
+	fastd_cipher_state_t *cipher_state;
 
 	fastd_crypto_ghash_state_t *cstate_ghash;
 };
 
 
-static bool method_provides(fastd_context_t *ctx UNUSED, const char *name) {
-	return !strcmp(name, "aes128-gcm");
+static bool cipher_get(fastd_context_t *ctx, const char *name, const fastd_cipher_t **cipher, fastd_cipher_context_t **cctx) {
+	size_t len = strlen(name);
+
+	if (len < 4)
+		return NULL;
+
+	if (strcmp(name+len-4, "-gcm"))
+		return NULL;
+
+	char name_ctr[len+1];
+	memcpy(name_ctr, name, len-3);
+	strncpy(name_ctr+len-3, "ctr", 4);
+
+	if (ctx) {
+		*cipher = fastd_cipher_get_by_name(ctx, name_ctr, cctx);
+		return *cipher;
+	}
+	else {
+		return fastd_cipher_available(name_ctr);
+	}
+}
+
+
+static bool method_provides(const char *name) {
+	return cipher_get(NULL, name, NULL, NULL);
 }
 
 static size_t method_max_packet_size(fastd_context_t *ctx) {
@@ -70,21 +93,20 @@ static size_t method_key_length(fastd_context_t *ctx UNUSED) {
 	return sizeof(fastd_block128_t);
 }
 
-static fastd_method_session_state_t* method_session_init(fastd_context_t *ctx, const char *name UNUSED, const uint8_t *secret, bool initiator) {
+static fastd_method_session_state_t* method_session_init(fastd_context_t *ctx, const char *name, const uint8_t *secret, bool initiator) {
 	fastd_method_session_state_t *session = malloc(sizeof(fastd_method_session_state_t));
 
 	fastd_method_common_init(ctx, &session->common, initiator);
 
-	session->aes128_ctr = fastd_cipher_get_by_name(ctx, "aes128-ctr", &session->aes128_ctr_ctx);
-	if (!session->aes128_ctr)
-		exit_bug(ctx, "aes128-gcm: can't instanciate aes128-ctr");
+	if (!cipher_get(ctx, name, &session->cipher, &session->cipher_ctx))
+		exit_bug(ctx, "generic-gcm: can't instanciate cipher");
 
-	session->aes128_ctr_state = session->aes128_ctr->init_state(ctx, session->aes128_ctr_ctx, secret);
+	session->cipher_state = session->cipher->init_state(ctx, session->cipher_ctx, secret);
 
 	static const fastd_block128_t zeroblock = {};
 	fastd_block128_t H;
 
-	session->aes128_ctr->crypt(ctx, session->aes128_ctr_state, &H, &zeroblock, sizeof(fastd_block128_t), &zeroblock);
+	session->cipher->crypt(ctx, session->cipher_state, &H, &zeroblock, sizeof(fastd_block128_t), &zeroblock);
 
 	session->cstate_ghash = ctx->conf->crypto_ghash->set_h(ctx, ctx->crypto_ghash, &H);
 
@@ -93,7 +115,7 @@ static fastd_method_session_state_t* method_session_init(fastd_context_t *ctx, c
 
 static fastd_method_session_state_t* method_session_init_compat(fastd_context_t *ctx, const char *name, const uint8_t *secret, size_t length, bool initiator) {
 	if (length < sizeof(fastd_block128_t))
-		exit_bug(ctx, "aes128-gcm: tried to init with short secret");
+		exit_bug(ctx, "generic-gcm: tried to init with short secret");
 
 	return method_session_init(ctx, name, secret, initiator);
 }
@@ -116,7 +138,7 @@ static void method_session_superseded(fastd_context_t *ctx, fastd_method_session
 
 static void method_session_free(fastd_context_t *ctx, fastd_method_session_state_t *session) {
 	if (session) {
-		session->aes128_ctr->free_state(ctx, session->aes128_ctr_state);
+		session->cipher->free_state(ctx, session->cipher_state);
 		ctx->conf->crypto_ghash->free_state(ctx, session->cstate_ghash);
 
 		secure_memzero(session, sizeof(fastd_method_session_state_t));
@@ -154,7 +176,7 @@ static bool method_encrypt(fastd_context_t *ctx, fastd_peer_t *peer UNUSED, fast
 	fastd_block128_t *outblocks = out->data;
 	fastd_block128_t sig;
 
-	bool ok = session->aes128_ctr->crypt(ctx, session->aes128_ctr_state, outblocks, inblocks, n_blocks*sizeof(fastd_block128_t), &nonce);
+	bool ok = session->cipher->crypt(ctx, session->cipher_state, outblocks, inblocks, n_blocks*sizeof(fastd_block128_t), &nonce);
 
 	if (ok) {
 		if (tail_len)
@@ -210,7 +232,7 @@ static bool method_decrypt(fastd_context_t *ctx, fastd_peer_t *peer, fastd_metho
 	fastd_block128_t *outblocks = out->data;
 	fastd_block128_t sig;
 
-	bool ok = session->aes128_ctr->crypt(ctx, session->aes128_ctr_state, outblocks, inblocks, n_blocks*sizeof(fastd_block128_t), &nonce);
+	bool ok = session->cipher->crypt(ctx, session->cipher_state, outblocks, inblocks, n_blocks*sizeof(fastd_block128_t), &nonce);
 
 	if (ok) {
 		if (tail_len)
@@ -238,7 +260,7 @@ static bool method_decrypt(fastd_context_t *ctx, fastd_peer_t *peer, fastd_metho
 	return true;
 }
 
-const fastd_method_t fastd_method_aes128_gcm = {
+const fastd_method_t fastd_method_generic_gcm = {
 	.provides = method_provides,
 
 	.max_packet_size = method_max_packet_size,
diff --git a/src/methods/methods.c.in b/src/methods/methods.c.in
index f39fbc1..8a8958c 100644
--- a/src/methods/methods.c.in
+++ b/src/methods/methods.c.in
@@ -33,10 +33,10 @@ static const fastd_method_t *const methods[] = { @METHOD_LIST@
 };
 
 
-const fastd_method_t* fastd_method_get_by_name(fastd_context_t *ctx, const char *name) {
+const fastd_method_t* fastd_method_get_by_name(const char *name) {
 	size_t i;
 	for (i = 0; i < array_size(methods); i++) {
-		if (methods[i]->provides(ctx, name))
+		if (methods[i]->provides(name))
 			return methods[i];
 	}
 
diff --git a/src/methods/null/null.c b/src/methods/null/null.c
index cba7931..e93f0cf 100644
--- a/src/methods/null/null.c
+++ b/src/methods/null/null.c
@@ -33,7 +33,7 @@ struct fastd_method_session_state {
 };
 
 
-static bool method_provides(fastd_context_t *ctx UNUSED, const char *name) {
+static bool method_provides(const char *name) {
 	return !strcmp(name, "null");
 }
 
diff --git a/src/methods/xsalsa20_poly1305/xsalsa20_poly1305.c b/src/methods/xsalsa20_poly1305/xsalsa20_poly1305.c
index 220e913..45bdc14 100644
--- a/src/methods/xsalsa20_poly1305/xsalsa20_poly1305.c
+++ b/src/methods/xsalsa20_poly1305/xsalsa20_poly1305.c
@@ -37,7 +37,7 @@ struct fastd_method_session_state {
 };
 
 
-static bool method_provides(fastd_context_t *ctx UNUSED, const char *name) {
+static bool method_provides(const char *name) {
 	return !strcmp(name, "xsalsa20-poly1305");
 }