From fc8c8d82f05911836208cc9169e103d5578ffd70 Mon Sep 17 00:00:00 2001 From: Matthias Schiffer Date: Mon, 28 Oct 2013 18:27:10 +0100 Subject: Unify duplicate code in xsalsa20-poly1305 and aes128-gcm methods --- src/methods/xsalsa20_poly1305/xsalsa20_poly1305.c | 119 ++++------------------ 1 file changed, 22 insertions(+), 97 deletions(-) (limited to 'src/methods/xsalsa20_poly1305/xsalsa20_poly1305.c') diff --git a/src/methods/xsalsa20_poly1305/xsalsa20_poly1305.c b/src/methods/xsalsa20_poly1305/xsalsa20_poly1305.c index d891aa5..0a9f2c8 100644 --- a/src/methods/xsalsa20_poly1305/xsalsa20_poly1305.c +++ b/src/methods/xsalsa20_poly1305/xsalsa20_poly1305.c @@ -25,58 +25,20 @@ #include +#include "../common.h" #include -#define NONCEBYTES 7 - - struct fastd_method_session_state { - struct timespec valid_till; - struct timespec refresh_after; + fastd_method_common_t common; uint8_t key[crypto_secretbox_xsalsa20poly1305_KEYBYTES]; - - uint8_t send_nonce[NONCEBYTES]; - uint8_t receive_nonce[NONCEBYTES]; - - struct timespec receive_last; - uint64_t receive_reorder_seen; }; -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 + crypto_secretbox_xsalsa20poly1305_ZEROBYTES - crypto_secretbox_xsalsa20poly1305_BOXZEROBYTES); + return (fastd_max_packet_size(ctx) + COMMON_NONCEBYTES + crypto_secretbox_xsalsa20poly1305_ZEROBYTES - crypto_secretbox_xsalsa20poly1305_BOXZEROBYTES); } static size_t method_min_encrypt_head_space(fastd_context_t *ctx UNUSED) { @@ -84,7 +46,7 @@ static size_t method_min_encrypt_head_space(fastd_context_t *ctx UNUSED) { } static size_t method_min_decrypt_head_space(fastd_context_t *ctx UNUSED) { - return (crypto_secretbox_xsalsa20poly1305_BOXZEROBYTES - NONCEBYTES); + return (crypto_secretbox_xsalsa20poly1305_BOXZEROBYTES - COMMON_NONCEBYTES); } static size_t method_min_tail_space(fastd_context_t *ctx UNUSED) { @@ -92,50 +54,32 @@ static size_t method_min_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 < crypto_secretbox_xsalsa20poly1305_KEYBYTES) exit_bug(ctx, "xsalsa20-poly1305: 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); memcpy(session->key, secret, crypto_secretbox_xsalsa20poly1305_KEYBYTES); - 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 UNUSED, fastd_method_session_state_t *session) { @@ -152,45 +96,37 @@ static bool method_encrypt(fastd_context_t *ctx, fastd_peer_t *peer UNUSED, fast *out = fastd_buffer_alloc(ctx, in.len, 0, 0); uint8_t nonce[crypto_secretbox_xsalsa20poly1305_NONCEBYTES]; - memcpy(nonce, session->send_nonce, NONCEBYTES); - memset(nonce+NONCEBYTES, 0, crypto_secretbox_xsalsa20poly1305_NONCEBYTES-NONCEBYTES); + memcpy(nonce, session->common.send_nonce, COMMON_NONCEBYTES); + memset(nonce+COMMON_NONCEBYTES, 0, crypto_secretbox_xsalsa20poly1305_NONCEBYTES-COMMON_NONCEBYTES); crypto_secretbox_xsalsa20poly1305(out->data, in.data, in.len, nonce, session->key); fastd_buffer_free(in); - fastd_buffer_push_head(ctx, out, crypto_secretbox_xsalsa20poly1305_BOXZEROBYTES-NONCEBYTES); - memcpy(out->data, session->send_nonce, NONCEBYTES); + fastd_buffer_push_head(ctx, out, crypto_secretbox_xsalsa20poly1305_BOXZEROBYTES-COMMON_NONCEBYTES); + memcpy(out->data, session->common.send_nonce, COMMON_NONCEBYTES); - increment_nonce(session->send_nonce); + 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) + if (in.len < COMMON_NONCEBYTES) return false; if (!method_session_is_valid(ctx, session)) return false; uint8_t nonce[crypto_secretbox_xsalsa20poly1305_NONCEBYTES]; - memcpy(nonce, in.data, NONCEBYTES); - memset(nonce+NONCEBYTES, 0, crypto_secretbox_xsalsa20poly1305_NONCEBYTES-NONCEBYTES); + memcpy(nonce, in.data, COMMON_NONCEBYTES); + memset(nonce+COMMON_NONCEBYTES, 0, crypto_secretbox_xsalsa20poly1305_NONCEBYTES-COMMON_NONCEBYTES); int64_t age; - if (!is_nonce_valid(nonce, session->receive_nonce, &age)) + if (!fastd_method_is_nonce_valid(ctx, &session->common, 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_pull_head(ctx, &in, crypto_secretbox_xsalsa20poly1305_BOXZEROBYTES-NONCEBYTES); + fastd_buffer_pull_head(ctx, &in, crypto_secretbox_xsalsa20poly1305_BOXZEROBYTES-COMMON_NONCEBYTES); memset(in.data, 0, crypto_secretbox_xsalsa20poly1305_BOXZEROBYTES); *out = fastd_buffer_alloc(ctx, in.len, 0, 0); @@ -199,28 +135,17 @@ static bool method_decrypt(fastd_context_t *ctx, fastd_peer_t *peer, fastd_metho fastd_buffer_free(*out); /* restore input buffer */ - fastd_buffer_push_head(ctx, &in, crypto_secretbox_xsalsa20poly1305_BOXZEROBYTES-NONCEBYTES); - memcpy(in.data, nonce, NONCEBYTES); + fastd_buffer_push_head(ctx, &in, crypto_secretbox_xsalsa20poly1305_BOXZEROBYTES-COMMON_NONCEBYTES); + memcpy(in.data, nonce, COMMON_NONCEBYTES); return false; } fastd_buffer_free(in); - if (age < 0) { - session->receive_reorder_seen >>= age; - session->receive_reorder_seen |= (1 >> (age+1)); - memcpy(session->receive_nonce, nonce, 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, age)) { fastd_buffer_free(*out); *out = fastd_buffer_alloc(ctx, crypto_secretbox_xsalsa20poly1305_ZEROBYTES, 0, 0); } - else { - pr_debug2(ctx, "accepting reordered packet from %P (age %u)", peer, (unsigned)age); - session->receive_reorder_seen |= (1 << (age-1)); - } fastd_buffer_push_head(ctx, out, crypto_secretbox_xsalsa20poly1305_ZEROBYTES); -- cgit v1.2.3