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Diffstat (limited to 'src/libstrongswan/plugins/chapoly/chapoly_xof.c')
-rw-r--r--src/libstrongswan/plugins/chapoly/chapoly_xof.c173
1 files changed, 173 insertions, 0 deletions
diff --git a/src/libstrongswan/plugins/chapoly/chapoly_xof.c b/src/libstrongswan/plugins/chapoly/chapoly_xof.c
new file mode 100644
index 000000000..2740a55b4
--- /dev/null
+++ b/src/libstrongswan/plugins/chapoly/chapoly_xof.c
@@ -0,0 +1,173 @@
+/*
+ * Copyright (C) 2016 Andreas Steffen
+ * HSR Hochschule fuer Technik Rapperswil
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License as published by the
+ * Free Software Foundation; either version 2 of the License, or (at your
+ * option) any later version. See <http://www.fsf.org/copyleft/gpl.txt>.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
+ * or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
+ * for more details.
+ */
+
+#include "chapoly_xof.h"
+#include "chapoly_drv.h"
+
+typedef struct private_chapoly_xof_t private_chapoly_xof_t;
+
+/**
+ * Private data of an chapoly_xof_t object.
+ */
+struct private_chapoly_xof_t {
+
+ /**
+ * Public chapoly_xof_t interface.
+ */
+ chapoly_xof_t public;
+
+ /**
+ * Latest block of the ChaCha20 stream.
+ */
+ uint8_t stream[CHACHA_BLOCK_SIZE];
+
+ /**
+ * Index pointing to the current position in the stream
+ */
+ u_int stream_index;
+
+ /**
+ * Driver backend
+ */
+ chapoly_drv_t *drv;
+};
+
+METHOD(xof_t, get_type, ext_out_function_t,
+ private_chapoly_xof_t *this)
+{
+ return XOF_CHACHA20;
+}
+
+METHOD(xof_t, get_bytes, bool,
+ private_chapoly_xof_t *this, size_t out_len, uint8_t *buffer)
+{
+ size_t index = 0, len, blocks;
+
+ /* empty the stream buffer first */
+ len = min(out_len, CHACHA_BLOCK_SIZE - this->stream_index);
+ if (len)
+ {
+ memcpy(buffer, this->stream + this->stream_index, len);
+ index += len;
+ this->stream_index += len;
+ }
+
+ /* copy whole stream blocks directly to output buffer */
+ blocks = (out_len - index) / CHACHA_BLOCK_SIZE;
+ while (blocks--)
+ {
+ if (!this->drv->chacha(this->drv, buffer + index))
+ {
+ return FALSE;
+ }
+ index += CHACHA_BLOCK_SIZE;
+ }
+
+ /* refill the stream buffer if some more output bytes are needed */
+ len = out_len - index;
+ if (len)
+ {
+ if (!this->drv->chacha(this->drv, this->stream))
+ {
+ return FALSE;
+ }
+ memcpy(buffer + index, this->stream, len);
+ this->stream_index = len;
+ }
+
+ return TRUE;
+}
+
+METHOD(xof_t, allocate_bytes, bool,
+ private_chapoly_xof_t *this, size_t out_len, chunk_t *chunk)
+{
+ *chunk = chunk_alloc(out_len);
+
+ if (!get_bytes(this, out_len, chunk->ptr))
+ {
+ chunk_free(chunk);
+ return FALSE;
+ }
+
+ return TRUE;
+}
+
+METHOD(xof_t, get_block_size, size_t,
+ private_chapoly_xof_t *this)
+{
+ return CHACHA_BLOCK_SIZE;
+}
+
+METHOD(xof_t, get_seed_size, size_t,
+ private_chapoly_xof_t *this)
+{
+ return CHACHA_KEY_SIZE + CHACHA_SALT_SIZE + CHACHA_IV_SIZE;
+}
+
+METHOD(xof_t, set_seed, bool,
+ private_chapoly_xof_t *this, chunk_t seed)
+{
+ this->stream_index = CHACHA_BLOCK_SIZE;
+
+ return seed.len == get_seed_size(this) &&
+ this->drv->set_key(this->drv, "expand 32-byte k",
+ seed.ptr, seed.ptr + CHACHA_KEY_SIZE) &&
+ this->drv->init(this->drv,
+ seed.ptr + CHACHA_KEY_SIZE + CHACHA_SALT_SIZE);
+}
+
+METHOD(xof_t, destroy, void,
+ private_chapoly_xof_t *this)
+{
+ this->drv->destroy(this->drv);
+ free(this);
+}
+
+/**
+ * See header
+ */
+chapoly_xof_t *chapoly_xof_create(ext_out_function_t algorithm)
+{
+ private_chapoly_xof_t *this;
+ chapoly_drv_t *drv;
+
+ if (algorithm != XOF_CHACHA20)
+ {
+ return NULL;
+ }
+
+ drv = chapoly_drv_probe();
+ if (!drv)
+ {
+ return NULL;
+ }
+
+ INIT(this,
+ .public = {
+ .xof_interface = {
+ .get_type = _get_type,
+ .get_bytes = _get_bytes,
+ .allocate_bytes = _allocate_bytes,
+ .get_block_size = _get_block_size,
+ .get_seed_size = _get_seed_size,
+ .set_seed = _set_seed,
+ .destroy = _destroy,
+ },
+ },
+ .drv = drv,
+ );
+
+ return &this->public;
+}