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authorMatthias Schiffer <mschiffer@universe-factory.net>2013-10-28 18:27:10 +0100
committerMatthias Schiffer <mschiffer@universe-factory.net>2013-10-28 18:31:02 +0100
commitfc8c8d82f05911836208cc9169e103d5578ffd70 (patch)
tree06aad5eebfa87982ae95a76bb5644161fc73c6df /src/methods/aes128_gcm
parent095ca93d81cfae0fcb137919231810577c556404 (diff)
downloadfastd-fc8c8d82f05911836208cc9169e103d5578ffd70.tar
fastd-fc8c8d82f05911836208cc9169e103d5578ffd70.zip
Unify duplicate code in xsalsa20-poly1305 and aes128-gcm methods
Diffstat (limited to 'src/methods/aes128_gcm')
-rw-r--r--src/methods/aes128_gcm/aes128_gcm.c115
1 files changed, 21 insertions, 94 deletions
diff --git a/src/methods/aes128_gcm/aes128_gcm.c b/src/methods/aes128_gcm/aes128_gcm.c
index 46dba5c..610df7c 100644
--- a/src/methods/aes128_gcm/aes128_gcm.c
+++ b/src/methods/aes128_gcm/aes128_gcm.c
@@ -26,57 +26,21 @@
#include <fastd.h>
#include <crypto.h>
+#include "../common.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_method_common_t common;
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));
+ return (fastd_max_packet_size(ctx) + COMMON_NONCEBYTES + sizeof(fastd_block128_t));
}
@@ -98,18 +62,12 @@ static size_t method_min_decrypt_tail_space(fastd_context_t *ctx UNUSED) {
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_method_common_init(ctx, &session->common, initiator);
fastd_block128_t key;
memcpy(key.b, secret, sizeof(fastd_block128_t));
@@ -122,39 +80,27 @@ static fastd_method_session_state_t* method_session_init(fastd_context_t *ctx, u
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));
+ 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 (session->send_nonce[0] & 1);
+ 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 timespec_after(&ctx->now, &session->refresh_after);
+ 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) {
- 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;
+ 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) {
+ if (session) {
ctx->conf->crypto_aes128ctr->free_state(ctx, session->cstate_aes128ctr);
ctx->conf->crypto_ghash->free_state(ctx, session->cstate_ghash);
@@ -177,14 +123,14 @@ static bool method_encrypt(fastd_context_t *ctx, fastd_peer_t *peer UNUSED, fast
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);
+ *out = fastd_buffer_alloc(ctx, in.len, alignto(COMMON_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);
+ memcpy(nonce.b, session->common.send_nonce, COMMON_NONCEBYTES);
+ memset(nonce.b+COMMON_NONCEBYTES, 0, sizeof(fastd_block128_t)-COMMON_NONCEBYTES-1);
nonce.b[sizeof(fastd_block128_t)-1] = 1;
int n_blocks = (in.len+sizeof(fastd_block128_t)-1)/sizeof(fastd_block128_t);
@@ -215,38 +161,30 @@ static bool method_encrypt(fastd_context_t *ctx, fastd_peer_t *peer UNUSED, fast
fastd_buffer_free(in);
- fastd_buffer_pull_head(ctx, out, NONCEBYTES);
- memcpy(out->data, session->send_nonce, NONCEBYTES);
- increment_nonce(session->send_nonce);
+ fastd_buffer_pull_head(ctx, out, COMMON_NONCEBYTES);
+ memcpy(out->data, session->common.send_nonce, COMMON_NONCEBYTES);
+ fastd_method_increment_nonce(&session->common);
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))
+ if (in.len < COMMON_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);
+ memcpy(nonce.b, in.data, COMMON_NONCEBYTES);
+ memset(nonce.b+COMMON_NONCEBYTES, 0, sizeof(fastd_block128_t)-COMMON_NONCEBYTES-1);
nonce.b[sizeof(fastd_block128_t)-1] = 1;
int64_t age;
- if (!is_nonce_valid(nonce.b, session->receive_nonce, &age))
+ if (!fastd_method_is_nonce_valid(ctx, &session->common, nonce.b, &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);
+ fastd_buffer_push_head(ctx, &in, COMMON_NONCEBYTES);
size_t tail_len = alignto(in.len, sizeof(fastd_block128_t))-in.len;
*out = fastd_buffer_alloc(ctx, in.len, 0, tail_len);
@@ -277,21 +215,10 @@ static bool method_decrypt(fastd_context_t *ctx, fastd_peer_t *peer, fastd_metho
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);
+ if (!fastd_method_reorder_check(ctx, peer, &session->common, nonce.b, 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;
}