summaryrefslogtreecommitdiffstats
path: root/src/method_aes128_gcm.c
diff options
context:
space:
mode:
Diffstat (limited to 'src/method_aes128_gcm.c')
-rw-r--r--src/method_aes128_gcm.c317
1 files changed, 0 insertions, 317 deletions
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 <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.
-*/
-
-
-#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,
-};