From 095ca93d81cfae0fcb137919231810577c556404 Mon Sep 17 00:00:00 2001 From: Matthias Schiffer Date: Mon, 28 Oct 2013 16:59:42 +0100 Subject: Organize method and protocol source files into distinct source directories --- src/method_aes128_gcm.c | 317 ------------------------------------------------ 1 file changed, 317 deletions(-) delete mode 100644 src/method_aes128_gcm.c (limited to 'src/method_aes128_gcm.c') diff --git a/src/method_aes128_gcm.c b/src/method_aes128_gcm.c deleted file mode 100644 index 1b91925..0000000 --- a/src/method_aes128_gcm.c +++ /dev/null @@ -1,317 +0,0 @@ -/* - 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 "crypto.h" - - -#define KEYBYTES 16 -#define NONCEBYTES 7 - -struct fastd_method_session_state { - struct timespec valid_till; - struct timespec refresh_after; - - uint8_t send_nonce[NONCEBYTES]; - uint8_t receive_nonce[NONCEBYTES]; - - struct timespec receive_last; - uint64_t receive_reorder_seen; - - fastd_crypto_aes128ctr_state_t *cstate_aes128ctr; - fastd_crypto_ghash_state_t *cstate_ghash; -}; - - -static inline void increment_nonce(uint8_t nonce[NONCEBYTES]) { - nonce[0] += 2; - - if (nonce[0] == 0 || nonce[0] == 1) { - int i; - for (i = 1; i < NONCEBYTES; i++) { - nonce[i]++; - if (nonce[i] != 0) - break; - } - } -} - -static inline bool is_nonce_valid(const uint8_t nonce[NONCEBYTES], const uint8_t old_nonce[NONCEBYTES], int64_t *age) { - if ((nonce[0] & 1) != (old_nonce[0] & 1)) - return false; - - int i; - *age = 0; - - for (i = NONCEBYTES-1; i >= 0; i--) { - *age *= 256; - *age += old_nonce[i]-nonce[i]; - } - - *age /= 2; - return true; -} - -static size_t method_max_packet_size(fastd_context_t *ctx) { - return (fastd_max_packet_size(ctx) + NONCEBYTES + sizeof(fastd_block128_t)); -} - - -static size_t method_min_encrypt_head_space(fastd_context_t *ctx UNUSED) { - return sizeof(fastd_block128_t); -} - -static size_t method_min_decrypt_head_space(fastd_context_t *ctx UNUSED) { - return 0; -} - -static size_t method_min_encrypt_tail_space(fastd_context_t *ctx UNUSED) { - return (sizeof(fastd_block128_t)-1); -} - -static size_t method_min_decrypt_tail_space(fastd_context_t *ctx UNUSED) { - return (2*sizeof(fastd_block128_t)-1); -} - - -static fastd_method_session_state_t* method_session_init(fastd_context_t *ctx, uint8_t *secret, size_t length, bool initiator) { - int i; - - if (length < KEYBYTES) - exit_bug(ctx, "aes128-gcm: tried to init with short secret"); - - fastd_method_session_state_t *session = malloc(sizeof(fastd_method_session_state_t)); - - session->valid_till = ctx->now; - session->valid_till.tv_sec += ctx->conf->key_valid; - - session->refresh_after = ctx->now; - session->refresh_after.tv_sec += ctx->conf->key_refresh - fastd_rand(ctx, 0, ctx->conf->key_refresh_splay); - - fastd_block128_t key; - memcpy(key.b, secret, sizeof(fastd_block128_t)); - session->cstate_aes128ctr = ctx->conf->crypto_aes128ctr->set_key(ctx, ctx->crypto_aes128ctr, &key); - - static const fastd_block128_t zeroblock = {}; - fastd_block128_t H; - - ctx->conf->crypto_aes128ctr->crypt(ctx, session->cstate_aes128ctr, &H, &zeroblock, sizeof(fastd_block128_t), &zeroblock); - - session->cstate_ghash = ctx->conf->crypto_ghash->set_h(ctx, ctx->crypto_ghash, &H); - - session->send_nonce[0] = initiator ? 3 : 2; - session->receive_nonce[0] = initiator ? 0 : 1; - - for (i = 1; i < NONCEBYTES; i++) { - session->send_nonce[i] = 0; - session->receive_nonce[i] = 0; - } - - return session; -} - -static bool method_session_is_valid(fastd_context_t *ctx, fastd_method_session_state_t *session) { - return (session && timespec_after(&session->valid_till, &ctx->now)); -} - -static bool method_session_is_initiator(fastd_context_t *ctx UNUSED, fastd_method_session_state_t *session) { - return (session->send_nonce[0] & 1); -} - -static bool method_session_want_refresh(fastd_context_t *ctx, fastd_method_session_state_t *session) { - return timespec_after(&ctx->now, &session->refresh_after); -} - -static void method_session_superseded(fastd_context_t *ctx, fastd_method_session_state_t *session) { - struct timespec valid_max = ctx->now; - valid_max.tv_sec += ctx->conf->key_valid_old; - - if (timespec_after(&session->valid_till, &valid_max)) - session->valid_till = valid_max; -} - -static void method_session_free(fastd_context_t *ctx, fastd_method_session_state_t *session) { - if(session) { - ctx->conf->crypto_aes128ctr->free_state(ctx, session->cstate_aes128ctr); - ctx->conf->crypto_ghash->free_state(ctx, session->cstate_ghash); - - secure_memzero(session, sizeof(fastd_method_session_state_t)); - free(session); - } -} - -static inline void put_size(fastd_block128_t *out, size_t len) { - memset(out, 0, sizeof(fastd_block128_t)-5); - out->b[sizeof(fastd_block128_t)-5] = len >> 29; - out->b[sizeof(fastd_block128_t)-4] = len >> 21; - out->b[sizeof(fastd_block128_t)-3] = len >> 13; - out->b[sizeof(fastd_block128_t)-2] = len >> 5; - out->b[sizeof(fastd_block128_t)-1] = len << 3; -} - -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, sizeof(fastd_block128_t)); - memset(in.data, 0, 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(NONCEBYTES, 16), sizeof(fastd_block128_t)+tail_len); - - if (tail_len) - memset(in.data+in.len, 0, tail_len); - - fastd_block128_t nonce; - memcpy(nonce.b, session->send_nonce, NONCEBYTES); - memset(nonce.b+NONCEBYTES, 0, sizeof(fastd_block128_t)-NONCEBYTES-1); - nonce.b[sizeof(fastd_block128_t)-1] = 1; - - int n_blocks = (in.len+sizeof(fastd_block128_t)-1)/sizeof(fastd_block128_t); - - fastd_block128_t *inblocks = in.data; - fastd_block128_t *outblocks = out->data; - fastd_block128_t sig; - - bool ok = ctx->conf->crypto_aes128ctr->crypt(ctx, session->cstate_aes128ctr, outblocks, inblocks, n_blocks*sizeof(fastd_block128_t), &nonce); - - if (ok) { - if (tail_len) - memset(out->data+out->len, 0, tail_len); - - put_size(&outblocks[n_blocks], in.len-sizeof(fastd_block128_t)); - - ok = ctx->conf->crypto_ghash->hash(ctx, session->cstate_ghash, &sig, outblocks+1, n_blocks); - } - - if (!ok) { - /* restore original buffer */ - fastd_buffer_push_head(ctx, &in, sizeof(fastd_block128_t)); - fastd_buffer_free(*out); - return false; - } - - xor_a(&outblocks[0], &sig); - - fastd_buffer_free(in); - - fastd_buffer_pull_head(ctx, out, NONCEBYTES); - memcpy(out->data, session->send_nonce, NONCEBYTES); - increment_nonce(session->send_nonce); - - 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 < NONCEBYTES+sizeof(fastd_block128_t)) - return false; - - if (!method_session_is_valid(ctx, session)) - return false; - - fastd_block128_t nonce; - memcpy(nonce.b, in.data, NONCEBYTES); - memset(nonce.b+NONCEBYTES, 0, sizeof(fastd_block128_t)-NONCEBYTES-1); - nonce.b[sizeof(fastd_block128_t)-1] = 1; - - int64_t age; - if (!is_nonce_valid(nonce.b, session->receive_nonce, &age)) - return false; - - if (age >= 0) { - if (timespec_diff(&ctx->now, &session->receive_last) > (int)ctx->conf->reorder_time*1000) - return false; - - if (age > ctx->conf->reorder_count) - return false; - } - - fastd_buffer_push_head(ctx, &in, NONCEBYTES); - - 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 = (in.len+sizeof(fastd_block128_t)-1)/sizeof(fastd_block128_t); - - fastd_block128_t *inblocks = in.data; - fastd_block128_t *outblocks = out->data; - fastd_block128_t sig; - - bool ok = ctx->conf->crypto_aes128ctr->crypt(ctx, session->cstate_aes128ctr, outblocks, inblocks, n_blocks*sizeof(fastd_block128_t), &nonce); - - if (ok) { - if (tail_len) - memset(in.data+in.len, 0, tail_len); - - put_size(&inblocks[n_blocks], in.len-sizeof(fastd_block128_t)); - - ok = ctx->conf->crypto_ghash->hash(ctx, session->cstate_ghash, &sig, inblocks+1, n_blocks); - } - - if (!ok || memcmp(&sig, &outblocks[0], sizeof(fastd_block128_t)) != 0) { - fastd_buffer_free(*out); - return false; - } - - fastd_buffer_free(in); - - fastd_buffer_push_head(ctx, out, sizeof(fastd_block128_t)); - - if (age < 0) { - session->receive_reorder_seen >>= age; - session->receive_reorder_seen |= (1 >> (age+1)); - memcpy(session->receive_nonce, nonce.b, NONCEBYTES); - session->receive_last = ctx->now; - } - else if (age == 0 || session->receive_reorder_seen & (1 << (age-1))) { - pr_debug(ctx, "dropping duplicate packet from %P (age %u)", peer, (unsigned)age); - fastd_buffer_free(*out); - *out = fastd_buffer_alloc(ctx, 0, 0, 0); - } - else { - pr_debug2(ctx, "accepting reordered packet from %P (age %u)", peer, (unsigned)age); - session->receive_reorder_seen |= (1 << (age-1)); - } - - return true; -} - -const fastd_method_t fastd_method_aes128_gcm = { - .name = "aes128-gcm", - - .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_encrypt_tail_space, - .min_decrypt_tail_space = method_min_decrypt_tail_space, - - .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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