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-rw-r--r--src/libstrongswan/plugins/hmac/hmac.c214
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diff --git a/src/libstrongswan/plugins/hmac/hmac.c b/src/libstrongswan/plugins/hmac/hmac.c
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+/*
+ * Copyright (C) 2005-2006 Martin Willi
+ * Copyright (C) 2005 Jan Hutter
+ * Hochschule fuer Technik Rapperswil
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General hmac 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 hmac License
+ * for more details.
+ *
+ * $Id: hmac.c 3488 2008-02-21 15:10:02Z martin $
+ */
+
+#include <string.h>
+
+#include "hmac.h"
+
+
+typedef struct private_hmac_t private_hmac_t;
+
+/**
+ * Private data of a hmac_t object.
+ *
+ * The variable names are the same as in the RFC.
+ */
+struct private_hmac_t {
+ /**
+ * Public hmac_t interface.
+ */
+ hmac_t hmac;
+
+ /**
+ * Block size, as in RFC.
+ */
+ u_int8_t b;
+
+ /**
+ * Hash function.
+ */
+ hasher_t *h;
+
+ /**
+ * Previously xor'ed key using opad.
+ */
+ chunk_t opaded_key;
+
+ /**
+ * Previously xor'ed key using ipad.
+ */
+ chunk_t ipaded_key;
+};
+
+/**
+ * Implementation of hmac_t.get_mac.
+ */
+static void get_mac(private_hmac_t *this, chunk_t data, u_int8_t *out)
+{
+ /* H(K XOR opad, H(K XOR ipad, text))
+ *
+ * if out is NULL, we append text to the inner hash.
+ * else, we complete the inner and do the outer.
+ *
+ */
+
+ u_int8_t buffer[this->h->get_hash_size(this->h)];
+ chunk_t inner;
+
+ if (out == NULL)
+ {
+ /* append data to inner */
+ this->h->get_hash(this->h, data, NULL);
+ }
+ else
+ {
+ /* append and do outer hash */
+ inner.ptr = buffer;
+ inner.len = this->h->get_hash_size(this->h);
+
+ /* complete inner */
+ this->h->get_hash(this->h, data, buffer);
+
+ /* do outer */
+ this->h->get_hash(this->h, this->opaded_key, NULL);
+ this->h->get_hash(this->h, inner, out);
+
+ /* reinit for next call */
+ this->h->get_hash(this->h, this->ipaded_key, NULL);
+ }
+}
+
+/**
+ * Implementation of hmac_t.allocate_mac.
+ */
+static void allocate_mac(private_hmac_t *this, chunk_t data, chunk_t *out)
+{
+ /* allocate space and use get_mac */
+ if (out == NULL)
+ {
+ /* append mode */
+ this->hmac.get_mac(&(this->hmac), data, NULL);
+ }
+ else
+ {
+ out->len = this->h->get_hash_size(this->h);
+ out->ptr = malloc(out->len);
+ this->hmac.get_mac(&(this->hmac), data, out->ptr);
+ }
+}
+
+/**
+ * Implementation of hmac_t.get_block_size.
+ */
+static size_t get_block_size(private_hmac_t *this)
+{
+ return this->h->get_hash_size(this->h);
+}
+
+/**
+ * Implementation of hmac_t.set_key.
+ */
+static void set_key(private_hmac_t *this, chunk_t key)
+{
+ int i;
+ u_int8_t buffer[this->b];
+
+ memset(buffer, 0, this->b);
+
+ if (key.len > this->b)
+ {
+ /* if key is too long, it will be hashed */
+ this->h->get_hash(this->h, key, buffer);
+ }
+ else
+ {
+ /* if not, just copy it in our pre-padded k */
+ memcpy(buffer, key.ptr, key.len);
+ }
+
+ /* apply ipad and opad to key */
+ for (i = 0; i < this->b; i++)
+ {
+ this->ipaded_key.ptr[i] = buffer[i] ^ 0x36;
+ this->opaded_key.ptr[i] = buffer[i] ^ 0x5C;
+ }
+
+ /* begin hashing of inner pad */
+ this->h->reset(this->h);
+ this->h->get_hash(this->h, this->ipaded_key, NULL);
+}
+
+/**
+ * Implementation of hmac_t.destroy.
+ */
+static void destroy(private_hmac_t *this)
+{
+ this->h->destroy(this->h);
+ free(this->opaded_key.ptr);
+ free(this->ipaded_key.ptr);
+ free(this);
+}
+
+/*
+ * Described in header
+ */
+hmac_t *hmac_create(hash_algorithm_t hash_algorithm)
+{
+ private_hmac_t *this = malloc_thing(private_hmac_t);
+
+ /* set hmac_t methods */
+ this->hmac.get_mac = (void (*)(hmac_t *,chunk_t,u_int8_t*))get_mac;
+ this->hmac.allocate_mac = (void (*)(hmac_t *,chunk_t,chunk_t*))allocate_mac;
+ this->hmac.get_block_size = (size_t (*)(hmac_t *))get_block_size;
+ this->hmac.set_key = (void (*)(hmac_t *,chunk_t))set_key;
+ this->hmac.destroy = (void (*)(hmac_t *))destroy;
+
+ /* set b, according to hasher */
+ switch (hash_algorithm)
+ {
+ case HASH_SHA1:
+ case HASH_MD5:
+ case HASH_SHA256:
+ this->b = 64;
+ break;
+ case HASH_SHA384:
+ case HASH_SHA512:
+ this->b = 128;
+ break;
+ default:
+ free(this);
+ return NULL;
+ }
+
+ /* build the hasher */
+ this->h = lib->crypto->create_hasher(lib->crypto, hash_algorithm);
+ if (this->h == NULL)
+ {
+ free(this);
+ return NULL;
+ }
+
+ /* build ipad and opad */
+ this->opaded_key.ptr = malloc(this->b);
+ this->opaded_key.len = this->b;
+
+ this->ipaded_key.ptr = malloc(this->b);
+ this->ipaded_key.len = this->b;
+
+ return &(this->hmac);
+}