From 9bb8a04e288d3df817a4328cce9e0ef8f96a0600 Mon Sep 17 00:00:00 2001 From: Matthias Schiffer Date: Tue, 19 Nov 2013 23:08:28 +0100 Subject: Add generic-poly1305 method --- src/methods/CMakeLists.txt | 1 + src/methods/generic_poly1305/CMakeLists.txt | 6 + src/methods/generic_poly1305/generic_poly1305.c | 273 ++++++++++++++++++++++++ 3 files changed, 280 insertions(+) create mode 100644 src/methods/generic_poly1305/CMakeLists.txt create mode 100644 src/methods/generic_poly1305/generic_poly1305.c diff --git a/src/methods/CMakeLists.txt b/src/methods/CMakeLists.txt index b9550ad..7ec701e 100644 --- a/src/methods/CMakeLists.txt +++ b/src/methods/CMakeLists.txt @@ -26,6 +26,7 @@ add_subdirectory(null) add_subdirectory(cipher_test) add_subdirectory(generic_gcm) add_subdirectory(generic_gmac) +add_subdirectory(generic_poly1305) add_subdirectory(xsalsa20_poly1305) diff --git a/src/methods/generic_poly1305/CMakeLists.txt b/src/methods/generic_poly1305/CMakeLists.txt new file mode 100644 index 0000000..cafa288 --- /dev/null +++ b/src/methods/generic_poly1305/CMakeLists.txt @@ -0,0 +1,6 @@ +fastd_method(generic-poly1305 + generic_poly1305.c +) +fastd_method_include_directories(generic-poly1305 ${NACL_INCLUDE_DIRS}) +fastd_method_link_libraries(generic-poly1305 method_common ${NACL_LIBRARIES}) +fastd_method_require(generic-poly1305 NACL) diff --git a/src/methods/generic_poly1305/generic_poly1305.c b/src/methods/generic_poly1305/generic_poly1305.c new file mode 100644 index 0000000..fdad118 --- /dev/null +++ b/src/methods/generic_poly1305/generic_poly1305.c @@ -0,0 +1,273 @@ +/* + Copyright (c) 2012-2013, Matthias Schiffer + 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. +*/ + + +#include "../../fastd.h" +#include "../common.h" + +#include + + +#define AUTHBLOCKS (block_count(crypto_onetimeauth_poly1305_KEYBYTES, sizeof(fastd_block128_t))) + + +struct fastd_method_session_state { + fastd_method_common_t common; + + const fastd_cipher_t *cipher; + const fastd_cipher_context_t *cipher_ctx; + fastd_cipher_state_t *cipher_state; + size_t ivlen; +}; + + +static bool cipher_get(fastd_context_t *ctx, const char *name, const fastd_cipher_t **cipher, const fastd_cipher_context_t **cctx) { + size_t len = strlen(name); + + if (len < 9) + return false; + + if (strcmp(name+len-9, "+poly1305")) + return false; + + char cipher_name[len-8]; + memcpy(cipher_name, name, len-9); + cipher_name[len-9] = 0; + + if (ctx) { + *cipher = fastd_cipher_get_by_name(ctx, cipher_name, cctx); + return *cipher; + } + else { + return fastd_cipher_available(cipher_name); + } +} + + +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) { + return (fastd_max_packet_size(ctx) + COMMON_HEADBYTES + crypto_onetimeauth_poly1305_BYTES); +} + +static size_t method_min_encrypt_head_space(fastd_context_t *ctx UNUSED) { + return AUTHBLOCKS*sizeof(fastd_block128_t); +} + +static size_t method_min_decrypt_head_space(fastd_context_t *ctx UNUSED) { + return AUTHBLOCKS*sizeof(fastd_block128_t) - crypto_onetimeauth_poly1305_BYTES; +} + +static size_t method_min_tail_space(fastd_context_t *ctx UNUSED) { + return (sizeof(fastd_block128_t)-1); +} + + +static size_t method_key_length(fastd_context_t *ctx, const char *name) { + const fastd_cipher_t *cipher = NULL; + const fastd_cipher_context_t *cctx; + if (!cipher_get(ctx, name, &cipher, &cctx)) + exit_bug(ctx, "generic-poly1305: can't get cipher key length"); + + return cipher->key_length(ctx, cctx); +} + +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); + + if (!cipher_get(ctx, name, &session->cipher, &session->cipher_ctx)) + exit_bug(ctx, "generic-poly1305: can't instanciate cipher"); + + session->cipher_state = session->cipher->init_state(ctx, session->cipher_ctx, secret); + + session->ivlen = session->cipher->iv_length(ctx, session->cipher_state); + if (session->ivlen <= COMMON_NONCEBYTES) + exit_bug(ctx, "generic-poly1305: iv_length to small"); + + return session; +} + +static bool method_session_is_valid(fastd_context_t *ctx, fastd_method_session_state_t *session) { + return (session && fastd_method_session_common_is_valid(ctx, &session->common)); +} + +static bool method_session_is_initiator(fastd_context_t *ctx UNUSED, fastd_method_session_state_t *session) { + return fastd_method_session_common_is_initiator(&session->common); +} + +static bool method_session_want_refresh(fastd_context_t *ctx, fastd_method_session_state_t *session) { + return fastd_method_session_common_want_refresh(ctx, &session->common); +} + +static void method_session_superseded(fastd_context_t *ctx, fastd_method_session_state_t *session) { + fastd_method_session_common_superseded(ctx, &session->common); +} + +static void method_session_free(fastd_context_t *ctx, fastd_method_session_state_t *session) { + if (session) { + session->cipher->free_state(ctx, session->cipher_state); + free(session); + } +} + +static bool method_encrypt(fastd_context_t *ctx, fastd_peer_t *peer UNUSED, fastd_method_session_state_t *session, fastd_buffer_t *out, fastd_buffer_t in) { + fastd_buffer_pull_head(ctx, &in, AUTHBLOCKS*sizeof(fastd_block128_t)); + memset(in.data, 0, AUTHBLOCKS*sizeof(fastd_block128_t)); + + size_t tail_len = alignto(in.len, sizeof(fastd_block128_t))-in.len; + *out = fastd_buffer_alloc(ctx, in.len, 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->ivlen]; + memset(nonce, 0, session->ivlen); + memcpy(nonce, session->common.send_nonce, COMMON_NONCEBYTES); + nonce[session->ivlen-1] = 1; + + int n_blocks = block_count(in.len, sizeof(fastd_block128_t)); + + fastd_block128_t *inblocks = in.data; + fastd_block128_t *outblocks = out->data; + uint8_t tag[crypto_onetimeauth_poly1305_BYTES]; + + bool ok = session->cipher->crypt(ctx, session->cipher_state, outblocks, inblocks, n_blocks*sizeof(fastd_block128_t), nonce); + + if (!ok) { + /* restore original buffer */ + fastd_buffer_push_head(ctx, &in, AUTHBLOCKS*sizeof(fastd_block128_t)); + fastd_buffer_free(*out); + return false; + } + + crypto_onetimeauth_poly1305(tag, (const uint8_t*)(outblocks+AUTHBLOCKS), in.len - AUTHBLOCKS*sizeof(fastd_block128_t), (const uint8_t*)outblocks); + + fastd_buffer_push_head(ctx, out, AUTHBLOCKS*sizeof(fastd_block128_t) - crypto_onetimeauth_poly1305_BYTES); + memcpy(out->data, tag, crypto_onetimeauth_poly1305_BYTES); + + fastd_buffer_free(in); + + fastd_buffer_pull_head(ctx, out, COMMON_HEADBYTES); + + memcpy(out->data, session->common.send_nonce, COMMON_NONCEBYTES); + fastd_method_increment_nonce(&session->common); + + ((uint8_t*)out->data)[COMMON_NONCEBYTES] = 0; /* flags */ + + return true; +} + +static bool method_decrypt(fastd_context_t *ctx, fastd_peer_t *peer, fastd_method_session_state_t *session, fastd_buffer_t *out, fastd_buffer_t in) { + if (in.len < COMMON_HEADBYTES+crypto_onetimeauth_poly1305_BYTES) + return false; + + if (!method_session_is_valid(ctx, session)) + return false; + + if (((const uint8_t*)in.data)[COMMON_NONCEBYTES]) /* flags */ + return false; + + uint8_t nonce[session->ivlen]; + memset(nonce, 0, session->ivlen); + memcpy(nonce, in.data, COMMON_NONCEBYTES); + nonce[session->ivlen-1] = 1; + + int64_t age; + if (!fastd_method_is_nonce_valid(ctx, &session->common, nonce, &age)) + return false; + + fastd_buffer_push_head(ctx, &in, COMMON_HEADBYTES); + + uint8_t tag[crypto_onetimeauth_poly1305_BYTES]; + memcpy(tag, in.data, crypto_onetimeauth_poly1305_BYTES); + + fastd_buffer_pull_head(ctx, &in, AUTHBLOCKS*sizeof(fastd_block128_t) - crypto_onetimeauth_poly1305_BYTES); + memset(in.data, 0, AUTHBLOCKS*sizeof(fastd_block128_t)); + + size_t tail_len = alignto(in.len, sizeof(fastd_block128_t))-in.len; + *out = fastd_buffer_alloc(ctx, in.len, 0, tail_len); + + int n_blocks = block_count(in.len, sizeof(fastd_block128_t)); + fastd_block128_t *inblocks = in.data; + fastd_block128_t *outblocks = out->data; + + bool ok = session->cipher->crypt(ctx, session->cipher_state, outblocks, inblocks, n_blocks*sizeof(fastd_block128_t), nonce); + + if (ok) { + if (tail_len) + memset(in.data+in.len, 0, tail_len); + + ok = (crypto_onetimeauth_poly1305_verify(tag, in.data+AUTHBLOCKS*sizeof(fastd_block128_t), in.len - AUTHBLOCKS*sizeof(fastd_block128_t), out->data) == 0); + } + + if (!ok) { + fastd_buffer_free(*out); + + /* restore input buffer */ + fastd_buffer_push_head(ctx, &in, AUTHBLOCKS*sizeof(fastd_block128_t) - crypto_onetimeauth_poly1305_BYTES); + memcpy(in.data, tag, crypto_onetimeauth_poly1305_BYTES); + fastd_buffer_pull_head(ctx, &in, COMMON_HEADBYTES); + memcpy(in.data, nonce, COMMON_NONCEBYTES); + ((uint8_t*)in.data)[COMMON_NONCEBYTES] = 0; + + return false; + } + + fastd_buffer_free(in); + + fastd_buffer_push_head(ctx, out, AUTHBLOCKS*sizeof(fastd_block128_t)); + + if (!fastd_method_reorder_check(ctx, peer, &session->common, nonce, age)) { + fastd_buffer_free(*out); + *out = fastd_buffer_alloc(ctx, 0, 0, 0); + } + + return true; +} + +const fastd_method_t fastd_method_generic_poly1305 = { + .provides = method_provides, + + .max_packet_size = method_max_packet_size, + .min_encrypt_head_space = method_min_encrypt_head_space, + .min_decrypt_head_space = method_min_decrypt_head_space, + .min_encrypt_tail_space = method_min_tail_space, + .min_decrypt_tail_space = method_min_tail_space, + + .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, +}; 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