--- /dev/null
+/*
+ * Copyright (C) 2022 Tobias Brunner, codelabs GmbH
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ */
+
+#define _GNU_SOURCE
+#include "botan_kdf.h"
+#include "botan_util.h"
+
+#include <botan/build.h>
+
+#ifdef BOTAN_HAS_HKDF
+
+#include <botan/ffi.h>
+
+typedef struct private_kdf_t private_kdf_t;
+
+/**
+ * Private data.
+ */
+struct private_kdf_t {
+
+ /**
+ * Public interface.
+ */
+ kdf_t public;
+
+ /**
+ * Name of the KDF algorithm in Botan.
+ */
+ char *name;
+
+ /**
+ * Key for KDF.
+ */
+ chunk_t key;
+
+ /**
+ * Salt for KDF.
+ */
+ chunk_t salt;
+
+#if BOTAN_VERSION_MAJOR == 2
+ /**
+ * Used for a manual length check in get_bytes().
+ */
+ size_t hash_size;
+#endif
+};
+
+METHOD(kdf_t, get_type, key_derivation_function_t,
+ private_kdf_t *this)
+{
+ return KDF_PRF_PLUS;
+}
+
+METHOD(kdf_t, get_bytes, bool,
+ private_kdf_t *this, size_t out_len, uint8_t *buffer)
+{
+#if BOTAN_VERSION_MAJOR == 2
+ /* Botan 2 doesn't check the length, just silently prevents wrapping the
+ * counter and returns truncated output, so do this manually */
+ if (out_len > this->hash_size * 255)
+ {
+ return FALSE;
+ }
+#endif
+ if (botan_kdf(this->name, buffer, out_len, this->key.ptr, this->key.len,
+ NULL, 0, this->salt.ptr, this->salt.len))
+ {
+ return FALSE;
+ }
+ return TRUE;
+}
+
+METHOD(kdf_t, allocate_bytes, bool,
+ private_kdf_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(kdf_t, set_param, bool,
+ private_kdf_t *this, kdf_param_t param, ...)
+{
+ chunk_t chunk;
+
+ switch (param)
+ {
+ case KDF_PARAM_KEY:
+ VA_ARGS_GET(param, chunk);
+ chunk_clear(&this->key);
+ this->key = chunk_clone(chunk);
+ break;
+ case KDF_PARAM_SALT:
+ VA_ARGS_GET(param, chunk);
+ chunk_clear(&this->salt);
+ this->salt = chunk_clone(chunk);
+ break;
+ }
+ return TRUE;
+}
+
+METHOD(kdf_t, destroy, void,
+ private_kdf_t *this)
+{
+ chunk_clear(&this->salt);
+ chunk_clear(&this->key);
+ free(this->name);
+ free(this);
+}
+
+/*
+ * Described in header
+ */
+kdf_t *botan_kdf_create(key_derivation_function_t algo, va_list args)
+{
+ private_kdf_t *this;
+ pseudo_random_function_t prf_alg;
+ const char *hash_name;
+ char *name, buf[8];
+
+ if (algo != KDF_PRF_PLUS)
+ {
+ return NULL;
+ }
+
+ VA_ARGS_VGET(args, prf_alg);
+ hash_name = botan_get_hash(hasher_algorithm_from_prf(prf_alg));
+ if (!hash_name)
+ {
+ return NULL;
+ }
+ if (asprintf(&name, "HKDF-Expand(%s)", hash_name) <= 0)
+ {
+ return NULL;
+ }
+
+ INIT(this,
+ .public = {
+ .get_type = _get_type,
+ .get_bytes = _get_bytes,
+ .allocate_bytes = _allocate_bytes,
+ .set_param = _set_param,
+ .destroy = _destroy,
+ },
+ .name = name,
+#if BOTAN_VERSION_MAJOR == 2
+ .hash_size = hasher_hash_size(hasher_algorithm_from_prf(prf_alg)),
+#endif
+ );
+
+ /* test if we can actually use the algorithm */
+ if (!get_bytes(this, sizeof(buf), buf))
+ {
+ destroy(this);
+ return NULL;
+ }
+ return &this->public;
+}
+
+#endif
--- /dev/null
+/*
+ * Copyright (C) 2022 Tobias Brunner, codelabs GmbH
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ */
+
+/**
+ * Implements key derivation functions (KDF) using Botan, in particular prf+,
+ * which is implemented via Botan's HKDF implementation.
+ *
+ * @defgroup botan_kdf botan_kdf
+ * @{ @ingroup botan_p
+ */
+
+#ifndef BOTAN_KDF_H_
+#define BOTAN_KDF_H_
+
+#include <crypto/kdfs/kdf.h>
+
+/**
+ * Creates a new kdf_t object.
+ *
+ * @param algo algorithm to instantiate
+ * @param args algorithm-specific arguments
+ * @return kdf_t object, NULL if not supported
+ */
+kdf_t *botan_kdf_create(key_derivation_function_t algo, va_list args);
+
+#endif /** BOTAN_KDF_H_ @}*/
projects / thirdparty / strongswan.git / commitdiff
