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authorMatthias Schiffer <mschiffer@universe-factory.net>2014-08-25 02:19:32 +0200
committerMatthias Schiffer <mschiffer@universe-factory.net>2014-08-25 02:19:32 +0200
commit9bf498263765328011ee105e5e7b3e1cc1b2bc3f (patch)
treea6e18dfd838633e7444ae5deab8fc2b130780ec2 /src/methods/generic_hmac_sha1
parentf2d84afd9d8373bf2778d1a1635384000c03f887 (diff)
downloadfastd-9bf498263765328011ee105e5e7b3e1cc1b2bc3f.tar
fastd-9bf498263765328011ee105e5e7b3e1cc1b2bc3f.zip
Experimental HMAC-SHA1 implementation
This adds experimental support for <cipher>+hmac-sha1 methods. It currently depends on OpenSSL and is not yet ready for production use.
Diffstat (limited to 'src/methods/generic_hmac_sha1')
-rw-r--r--src/methods/generic_hmac_sha1/CMakeLists.txt4
-rw-r--r--src/methods/generic_hmac_sha1/generic_hmac_sha1.c259
2 files changed, 263 insertions, 0 deletions
diff --git a/src/methods/generic_hmac_sha1/CMakeLists.txt b/src/methods/generic_hmac_sha1/CMakeLists.txt
new file mode 100644
index 0000000..b70bc1d
--- /dev/null
+++ b/src/methods/generic_hmac_sha1/CMakeLists.txt
@@ -0,0 +1,4 @@
+fastd_method(generic-hmac-sha1
+ generic_hmac_sha1.c
+)
+fastd_method_link_libraries(generic-hmac-sha1 method_common)
diff --git a/src/methods/generic_hmac_sha1/generic_hmac_sha1.c b/src/methods/generic_hmac_sha1/generic_hmac_sha1.c
new file mode 100644
index 0000000..530abe3
--- /dev/null
+++ b/src/methods/generic_hmac_sha1/generic_hmac_sha1.c
@@ -0,0 +1,259 @@
+/*
+ Copyright (c) 2012-2014, Matthias Schiffer <mschiffer@universe-factory.net>
+ All rights reserved.
+
+ Redistribution and use in source and binary forms, with or without
+ modification, are permitted provided that the following conditions are met:
+
+ 1. Redistributions of source code must retain the above copyright notice,
+ this list of conditions and the following disclaimer.
+ 2. Redistributions in binary form must reproduce the above copyright notice,
+ this list of conditions and the following disclaimer in the documentation
+ and/or other materials provided with the distribution.
+
+ THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+ AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
+ DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE
+ FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
+ SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
+ CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
+ OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+ OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+*/
+
+/**
+ \file
+
+ generic-gmac method provider
+
+ generic-gmac can combine any stream cipher with the GMAC authentication.
+*/
+
+
+#include "../../crypto.h"
+#include "../../method.h"
+#include "../common.h"
+
+
+/** A specific method provided by this provider */
+struct fastd_method {
+ const fastd_cipher_info_t *cipher_info; /**< The cipher used */
+ const fastd_mac_info_t *hmac_sha1_info; /**< HMAC-SHA1 */
+};
+
+/** The method-specific session state */
+struct fastd_method_session_state {
+ fastd_method_common_t common; /**< The common method state */
+
+ const fastd_method_t *method; /**< The specific method used */
+
+ const fastd_cipher_t *cipher; /**< The cipher implementation used */
+ fastd_cipher_state_t *cipher_state; /**< The cipher state */
+
+ const fastd_mac_t *hmac_sha1; /**< The HMAC-SHA1 implementation */
+ fastd_mac_state_t *hmac_sha1_state; /**< The HMAC-SHA1 state */
+};
+
+
+/** Instanciates a method using a name of the pattern "<cipher>+hmac-sha1" */
+static bool method_create_by_name(const char *name, fastd_method_t **method) {
+ fastd_method_t m;
+
+ m.hmac_sha1_info = fastd_mac_info_get_by_name("hmac-sha1");
+ if (!m.hmac_sha1_info)
+ return false;
+
+ size_t len = strlen(name);
+ if (len < 10)
+ return false;
+
+ if (strcmp(name+len-10, "+hmac-sha1"))
+ return false;
+
+ char cipher_name[len-9];
+ memcpy(cipher_name, name, len-10);
+ cipher_name[len-10] = 0;
+
+ m.cipher_info = fastd_cipher_info_get_by_name(cipher_name);
+ if (!m.cipher_info)
+ return false;
+
+ *method = fastd_new(fastd_method_t);
+ **method = m;
+
+ return true;
+}
+
+/** Frees a method */
+static void method_destroy(fastd_method_t *method) {
+ free(method);
+}
+
+/** Returns the key length used by a method */
+static size_t method_key_length(const fastd_method_t *method) {
+ return method->cipher_info->key_length + method->hmac_sha1_info->key_length;
+}
+
+/** Initializes a session */
+static fastd_method_session_state_t * method_session_init(const fastd_method_t *method, const uint8_t *secret, bool initiator) {
+ fastd_method_session_state_t *session = fastd_new(fastd_method_session_state_t);
+
+ fastd_method_common_init(&session->common, initiator);
+ session->method = method;
+
+ session->cipher = fastd_cipher_get(method->cipher_info);
+ session->cipher_state = session->cipher->init(secret);
+
+ session->hmac_sha1 = fastd_mac_get(method->hmac_sha1_info);
+ session->hmac_sha1_state = session->hmac_sha1->init(secret + method->cipher_info->key_length);
+
+ return session;
+}
+
+/** Checks if the session is currently valid */
+static bool method_session_is_valid(fastd_method_session_state_t *session) {
+ return (session && fastd_method_session_common_is_valid(&session->common));
+}
+
+/** Checks if this side is the initator of the session */
+static bool method_session_is_initiator(fastd_method_session_state_t *session) {
+ return fastd_method_session_common_is_initiator(&session->common);
+}
+
+/** Checks if the session should be refreshed */
+static bool method_session_want_refresh(fastd_method_session_state_t *session) {
+ return fastd_method_session_common_want_refresh(&session->common);
+}
+
+/** Marks the session as superseded */
+static void method_session_superseded(fastd_method_session_state_t *session) {
+ fastd_method_session_common_superseded(&session->common);
+}
+
+/** Frees the session state */
+static void method_session_free(fastd_method_session_state_t *session) {
+ if (session) {
+ session->cipher->free(session->cipher_state);
+ session->hmac_sha1->free(session->hmac_sha1_state);
+
+ free(session);
+ }
+}
+
+
+/** Encrypts and authenticates a packet */
+static bool method_encrypt(fastd_peer_t *peer UNUSED, fastd_method_session_state_t *session, fastd_buffer_t *out, fastd_buffer_t in) {
+ size_t tail_len = alignto(in.len, sizeof(fastd_block128_t))-in.len;
+ *out = fastd_buffer_alloc(in.len + sizeof(fastd_block128_t), alignto(COMMON_HEADBYTES, 16), sizeof(fastd_block128_t)+tail_len);
+
+ if (tail_len)
+ memset(in.data+in.len, 0, tail_len);
+
+ uint8_t nonce[session->method->cipher_info->iv_length] __attribute__((aligned(8)));
+ fastd_method_expand_nonce(nonce, session->common.send_nonce, sizeof(nonce));
+
+ fastd_block128_t *outblocks = out->data;
+ fastd_block128_t tag;
+
+ bool ok = session->cipher->crypt(session->cipher_state, outblocks+1, in.data, in.len, nonce);
+
+ if (ok) {
+ fastd_method_expand_nonce(out->data, session->common.send_nonce, sizeof(fastd_block128_t));
+ ok = session->hmac_sha1->digest(session->hmac_sha1_state, &tag, out->data, out->len);
+ }
+
+ if (!ok) {
+ fastd_buffer_free(*out);
+ return false;
+ }
+
+ outblocks[0] = tag;
+
+ fastd_buffer_free(in);
+
+ fastd_method_put_common_header(out, session->common.send_nonce, 0);
+ fastd_method_increment_nonce(&session->common);
+
+ return true;
+}
+
+/** Verifies and decrypts a packet */
+static bool method_decrypt(fastd_peer_t *peer, fastd_method_session_state_t *session, fastd_buffer_t *out, fastd_buffer_t in) {
+ if (in.len < COMMON_HEADBYTES+sizeof(fastd_block128_t))
+ return false;
+
+ if (!method_session_is_valid(session))
+ return false;
+
+ uint8_t in_nonce[COMMON_NONCEBYTES];
+ uint8_t flags;
+ int64_t age;
+ if (!fastd_method_handle_common_header(&session->common, &in, in_nonce, &flags, &age))
+ return false;
+
+ if (flags)
+ return false;
+
+ uint8_t nonce[session->method->cipher_info->iv_length] __attribute__((aligned(8)));
+ fastd_method_expand_nonce(nonce, in_nonce, sizeof(nonce));
+
+ fastd_block128_t *inblocks = in.data;
+ fastd_block128_t tag = inblocks[0], tag2;
+
+ fastd_method_expand_nonce(in.data, in_nonce, sizeof(fastd_block128_t));
+ bool ok = session->hmac_sha1->digest(session->hmac_sha1_state, &tag2, in.data, in.len);
+
+ if (ok && memcmp(&tag, &tag2, sizeof(fastd_block128_t)) != 0)
+ ok = false;
+
+ if (ok) {
+ size_t tail_len = alignto(in.len, sizeof(fastd_block128_t))-in.len;
+ *out = fastd_buffer_alloc(in.len - sizeof(fastd_block128_t), 0, tail_len);
+
+ ok = session->cipher->crypt(session->cipher_state, out->data, inblocks+1, in.len - sizeof(fastd_block128_t), nonce);
+
+ if (!ok)
+ fastd_buffer_free(*out);
+ }
+
+ if (!ok) {
+ inblocks[0] = tag;
+ return false;
+ }
+
+ fastd_buffer_free(in);
+
+ if (!fastd_method_reorder_check(peer, &session->common, in_nonce, age)) {
+ fastd_buffer_free(*out);
+ *out = fastd_buffer_alloc(0, 0, 0);
+ }
+
+ return true;
+}
+
+
+/** The generic-hmac-sha1 method provider */
+const fastd_method_provider_t fastd_method_generic_hmac_sha1 = {
+ .max_overhead = COMMON_HEADBYTES + sizeof(fastd_block128_t),
+ .min_encrypt_head_space = 0,
+ .min_decrypt_head_space = 0,
+ .min_encrypt_tail_space = sizeof(fastd_block128_t)-1,
+ .min_decrypt_tail_space = sizeof(fastd_block128_t)-1,
+
+ .create_by_name = method_create_by_name,
+ .destroy = method_destroy,
+
+ .key_length = method_key_length,
+
+ .session_init = method_session_init,
+ .session_is_valid = method_session_is_valid,
+ .session_is_initiator = method_session_is_initiator,
+ .session_want_refresh = method_session_want_refresh,
+ .session_superseded = method_session_superseded,
+ .session_free = method_session_free,
+
+ .encrypt = method_encrypt,
+ .decrypt = method_decrypt,
+};