Add small SHA256 implementation

The NaCl implementation has a code size of more than 10KiB.

4 files changed, 225 insertions, 39 deletions

diff --git a/src/CMakeLists.txt b/src/CMakeLists.txt
index 1fe0873..6c507ae 100644
--- a/src/CMakeLists.txt
+++ b/src/CMakeLists.txt
@@ -29,6 +29,7 @@ add_executable(fastd
   receive.c
   resolve.c
   send.c
+  sha256.c
   shell.c
   socket.c
   task.c
diff --git a/src/protocol_ec25519_fhmqvc.c b/src/protocol_ec25519_fhmqvc.c
index 01d2103..f6c170b 100644
--- a/src/protocol_ec25519_fhmqvc.c
+++ b/src/protocol_ec25519_fhmqvc.c
@@ -27,19 +27,18 @@
 #include "fastd.h"
 #include "handshake.h"
 #include "peer.h"
+#include "sha256.h"
 #include "task.h"
 
-#include <arpa/inet.h>
 
 #include <libuecc/ecc.h>
 #include <crypto_auth_hmacsha256.h>
-#include <crypto_hash_sha256.h>
 
 
 #define PUBLICKEYBYTES 32
 #define SECRETKEYBYTES 32
 #define HMACBYTES crypto_auth_hmacsha256_BYTES
-#define HASHBYTES crypto_hash_sha256_BYTES
+#define HASHBYTES FASTD_SHA256_HASH_BYTES
 
 
 #if HASHBYTES != crypto_auth_hmacsha256_KEYBYTES
@@ -279,16 +278,16 @@ static void respond_handshake(fastd_context_t *ctx, const fastd_socket_t *sock,
 			      const handshake_key_t *handshake_key, const ecc_int256_t *peer_handshake_key, const fastd_handshake_t *handshake, const fastd_method_t *method) {
 	pr_debug(ctx, "responding handshake with %P[%I]...", peer, remote_addr);
 
-	uint8_t hashinput[5*PUBLICKEYBYTES];
+	uint8_t hashinput[2*PUBLICKEYBYTES];
 	uint8_t hashbuf[HASHBYTES];
 	uint8_t hmacbuf[HMACBYTES];
 
-	memcpy(hashinput, handshake_key->public_key.p, PUBLICKEYBYTES);
-	memcpy(hashinput+PUBLICKEYBYTES, peer_handshake_key->p, PUBLICKEYBYTES);
-	memcpy(hashinput+2*PUBLICKEYBYTES, ctx->conf->protocol_config->public_key.p, PUBLICKEYBYTES);
-	memcpy(hashinput+3*PUBLICKEYBYTES, peer->protocol_config->public_key.p, PUBLICKEYBYTES);
-
-	crypto_hash_sha256(hashbuf, hashinput, 4*PUBLICKEYBYTES);
+	fastd_sha256_blocks(hashbuf,
+			    handshake_key->public_key.p,
+			    peer_handshake_key->p,
+			    ctx->conf->protocol_config->public_key.p,
+			    peer->protocol_config->public_key.p,
+			    NULL);
 
 	ecc_int256_t d = {{0}}, e = {{0}}, eb, s;
 
@@ -323,8 +322,13 @@ static void respond_handshake(fastd_context_t *ctx, const fastd_socket_t *sock,
 	ecc_25519_store_packed(&sigma, &work);
 
 	uint8_t shared_handshake_key[HASHBYTES];
-	memcpy(hashinput+4*PUBLICKEYBYTES, sigma.p, PUBLICKEYBYTES);
-	crypto_hash_sha256(shared_handshake_key, hashinput, 5*PUBLICKEYBYTES);
+	fastd_sha256_blocks(shared_handshake_key,
+			    handshake_key->public_key.p,
+			    peer_handshake_key->p,
+			    ctx->conf->protocol_config->public_key.p,
+			    peer->protocol_config->public_key.p,
+			    sigma.p,
+			    NULL);
 
 	memcpy(hashinput, ctx->conf->protocol_config->public_key.p, PUBLICKEYBYTES);
 	memcpy(hashinput+PUBLICKEYBYTES, handshake_key->public_key.p, PUBLICKEYBYTES);
@@ -346,9 +350,6 @@ static bool establish(fastd_context_t *ctx, fastd_peer_t *peer, const fastd_meth
 		      const fastd_peer_address_t *local_addr, const fastd_peer_address_t *remote_addr, bool initiator,
 		      const ecc_int256_t *A, const ecc_int256_t *B, const ecc_int256_t *X,
 		      const ecc_int256_t *Y, const ecc_int256_t *sigma, uint64_t serial) {
-	uint8_t hashinput[5*PUBLICKEYBYTES];
-	uint8_t hash[HASHBYTES];
-
 	if (serial <= peer->protocol_state->last_serial) {
 		pr_debug(ctx, "ignoring handshake from %P[%I] because of handshake key reuse", peer, remote_addr);
 		return false;
@@ -372,12 +373,8 @@ static bool establish(fastd_context_t *ctx, fastd_peer_t *peer, const fastd_meth
 		peer->protocol_state->old_session = (protocol_session_t){};
 	}
 
-	memcpy(hashinput, X->p, PUBLICKEYBYTES);
-	memcpy(hashinput+PUBLICKEYBYTES, Y->p, PUBLICKEYBYTES);
-	memcpy(hashinput+2*PUBLICKEYBYTES, A->p, PUBLICKEYBYTES);
-	memcpy(hashinput+3*PUBLICKEYBYTES, B->p, PUBLICKEYBYTES);
-	memcpy(hashinput+4*PUBLICKEYBYTES, sigma->p, PUBLICKEYBYTES);
-	crypto_hash_sha256(hash, hashinput, 5*PUBLICKEYBYTES);
+	uint8_t hash[HASHBYTES];
+	fastd_sha256_blocks(hash, X->p, Y->p, A->p, B->p, sigma->p, NULL);
 
 	peer->protocol_state->session.established = ctx->now;
 	peer->protocol_state->session.handshakes_cleaned = false;
@@ -410,16 +407,16 @@ static void finish_handshake(fastd_context_t *ctx, fastd_socket_t *sock, const f
 			     const fastd_handshake_t *handshake, const fastd_method_t *method) {
 	pr_debug(ctx, "finishing handshake with %P[%I]...", peer, remote_addr);
 
-	uint8_t hashinput[5*PUBLICKEYBYTES];
+	uint8_t hashinput[2*PUBLICKEYBYTES];
 	uint8_t hashbuf[HASHBYTES];
 	uint8_t hmacbuf[HMACBYTES];
 
-	memcpy(hashinput, peer_handshake_key->p, PUBLICKEYBYTES);
-	memcpy(hashinput+PUBLICKEYBYTES, handshake_key->public_key.p, PUBLICKEYBYTES);
-	memcpy(hashinput+2*PUBLICKEYBYTES, peer->protocol_config->public_key.p, PUBLICKEYBYTES);
-	memcpy(hashinput+3*PUBLICKEYBYTES, ctx->conf->protocol_config->public_key.p, PUBLICKEYBYTES);
-
-	crypto_hash_sha256(hashbuf, hashinput, 4*PUBLICKEYBYTES);
+	fastd_sha256_blocks(hashbuf,
+			    peer_handshake_key->p,
+			    handshake_key->public_key.p,
+			    peer->protocol_config->public_key.p,
+			    ctx->conf->protocol_config->public_key.p,
+			    NULL);
 
 	ecc_int256_t d = {{0}}, e = {{0}}, da, s;
 
@@ -454,8 +451,13 @@ static void finish_handshake(fastd_context_t *ctx, fastd_socket_t *sock, const f
 	ecc_25519_store_packed(&sigma, &work);
 
 	uint8_t shared_handshake_key[HASHBYTES];
-	memcpy(hashinput+4*PUBLICKEYBYTES, sigma.p, PUBLICKEYBYTES);
-	crypto_hash_sha256(shared_handshake_key, hashinput, 5*PUBLICKEYBYTES);
+	fastd_sha256_blocks(shared_handshake_key,
+			    peer_handshake_key->p,
+			    handshake_key->public_key.p,
+			    peer->protocol_config->public_key.p,
+			    ctx->conf->protocol_config->public_key.p,
+			    sigma.p,
+			    NULL);
 
 	memcpy(hashinput, peer->protocol_config->public_key.p, PUBLICKEYBYTES);
 	memcpy(hashinput+PUBLICKEYBYTES, peer_handshake_key->p, PUBLICKEYBYTES);
@@ -489,15 +491,15 @@ static void handle_finish_handshake(fastd_context_t *ctx, fastd_socket_t *sock,
 				    const fastd_handshake_t *handshake, const fastd_method_t *method) {
 	pr_debug(ctx, "handling handshake finish with %P[%I]...", peer, remote_addr);
 
-	uint8_t hashinput[5*PUBLICKEYBYTES];
+	uint8_t hashinput[2*PUBLICKEYBYTES];
 	uint8_t hashbuf[HASHBYTES];
 
-	memcpy(hashinput, handshake_key->public_key.p, PUBLICKEYBYTES);
-	memcpy(hashinput+PUBLICKEYBYTES, peer_handshake_key->p, PUBLICKEYBYTES);
-	memcpy(hashinput+2*PUBLICKEYBYTES, ctx->conf->protocol_config->public_key.p, PUBLICKEYBYTES);
-	memcpy(hashinput+3*PUBLICKEYBYTES, peer->protocol_config->public_key.p, PUBLICKEYBYTES);
-
-	crypto_hash_sha256(hashbuf, hashinput, 4*PUBLICKEYBYTES);
+	fastd_sha256_blocks(hashbuf,
+			    handshake_key->public_key.p,
+			    peer_handshake_key->p,
+			    ctx->conf->protocol_config->public_key.p,
+			    peer->protocol_config->public_key.p,
+			    NULL);
 
 	ecc_int256_t d = {{0}}, e = {{0}}, eb, s;
 
@@ -532,8 +534,13 @@ static void handle_finish_handshake(fastd_context_t *ctx, fastd_socket_t *sock,
 	ecc_25519_store_packed(&sigma, &work);
 
 	uint8_t shared_handshake_key[HASHBYTES];
-	memcpy(hashinput+4*PUBLICKEYBYTES, sigma.p, PUBLICKEYBYTES);
-	crypto_hash_sha256(shared_handshake_key, hashinput, 5*PUBLICKEYBYTES);
+	fastd_sha256_blocks(shared_handshake_key,
+			    handshake_key->public_key.p,
+			    peer_handshake_key->p,
+			    ctx->conf->protocol_config->public_key.p,
+			    peer->protocol_config->public_key.p,
+			    sigma.p,
+			    NULL);
 
 	memcpy(hashinput, peer->protocol_config->public_key.p, PUBLICKEYBYTES);
 	memcpy(hashinput+PUBLICKEYBYTES, peer_handshake_key->p, PUBLICKEYBYTES);
diff --git a/src/sha256.c b/src/sha256.c
new file mode 100644
index 0000000..639185c
--- /dev/null
+++ b/src/sha256.c
@@ -0,0 +1,139 @@
+/*
+  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 "sha256.h"
+
+#include <stdarg.h>
+#include <stdbool.h>
+#include <string.h>
+
+#include <arpa/inet.h>
+
+
+static inline uint32_t rotr(uint32_t x, int r) {
+	return (x >> r) | (x << (32-r));
+}
+
+void fastd_sha256_blocks(uint8_t out[FASTD_SHA256_HASH_BYTES], ...) {
+	static const uint32_t k[64] = {
+		0x428a2f98, 0x71374491, 0xb5c0fbcf, 0xe9b5dba5, 0x3956c25b, 0x59f111f1, 0x923f82a4, 0xab1c5ed5,
+		0xd807aa98, 0x12835b01, 0x243185be, 0x550c7dc3, 0x72be5d74, 0x80deb1fe, 0x9bdc06a7, 0xc19bf174,
+		0xe49b69c1, 0xefbe4786, 0x0fc19dc6, 0x240ca1cc, 0x2de92c6f, 0x4a7484aa, 0x5cb0a9dc, 0x76f988da,
+		0x983e5152, 0xa831c66d, 0xb00327c8, 0xbf597fc7, 0xc6e00bf3, 0xd5a79147, 0x06ca6351, 0x14292967,
+		0x27b70a85, 0x2e1b2138, 0x4d2c6dfc, 0x53380d13, 0x650a7354, 0x766a0abb, 0x81c2c92e, 0x92722c85,
+		0xa2bfe8a1, 0xa81a664b, 0xc24b8b70, 0xc76c51a3, 0xd192e819, 0xd6990624, 0xf40e3585, 0x106aa070,
+		0x19a4c116, 0x1e376c08, 0x2748774c, 0x34b0bcb5, 0x391c0cb3, 0x4ed8aa4a, 0x5b9cca4f, 0x682e6ff3,
+		0x748f82ee, 0x78a5636f, 0x84c87814, 0x8cc70208, 0x90befffa, 0xa4506ceb, 0xbef9a3f7, 0xc67178f2
+	};
+
+	uint32_t h[8] = {
+		0x6a09e667,
+		0xbb67ae85,
+		0x3c6ef372,
+		0xa54ff53a,
+		0x510e527f,
+		0x9b05688c,
+		0x1f83d9ab,
+		0x5be0cd19
+	};
+	unsigned count = 0, i;
+	va_list ap;
+	const uint32_t *in1, *in2;
+
+	va_start(ap, out);
+
+	do {
+		uint32_t w[64], v[8];
+
+		in1 = va_arg(ap, const uint32_t*);
+
+		if (in1) {
+			count++;
+			in2 = va_arg(ap, const uint32_t*);
+
+			if (in2)
+				count++;
+		}
+		else {
+			in2 = NULL;
+		}
+
+		if (in1) {
+			for (i = 0; i < 8; i++)
+				w[i] = ntohl(in1[i]);
+		}
+		else {
+			w[0] = 0x80000000;
+			memset(w+1, 0, 7*sizeof(uint32_t));
+		}
+
+		if (in2) {
+			for (i = 0; i < 8; i++)
+				w[i+8] = ntohl(in2[i]);
+		}
+		else {
+			w[8] = in1 ? 0x80000000 : 0;
+			memset(w+9, 0, 6*sizeof(uint32_t));
+			w[15] = count << 8;
+		}
+
+		for (i = 16; i < 64; i++) {
+			uint32_t s0 = rotr(w[i-15], 7) ^ rotr(w[i-15], 18) ^ (w[i-15] >> 3);
+			uint32_t s1 = rotr(w[i-2], 17) ^ rotr(w[i-2], 19) ^ (w[i-2] >> 10);
+			w[i] = w[i-16] + s0 + w[i-7] + s1;
+		}
+
+		memcpy(v, h, sizeof(v));
+
+		for (i = 0; i < 64; i++) {
+			uint32_t s1 = rotr(v[4], 6) ^ rotr(v[4], 11) ^ rotr(v[4], 25);
+			uint32_t ch = (v[4] & v[5]) ^ ((~v[4]) & v[6]);
+			uint32_t temp1 = v[7] + s1 + ch + k[i] + w[i];
+			uint32_t s0 = rotr(v[0], 2) ^ rotr(v[0], 13) ^ rotr(v[0], 22);
+			uint32_t maj = (v[0] & v[1]) ^ (v[0] & v[2]) ^ (v[1] & v[2]);
+			uint32_t temp2 = s0 + maj;
+
+			v[7] = v[6];
+			v[6] = v[5];
+			v[5] = v[4];
+			v[4] = v[3] + temp1;
+			v[3] = v[2];
+			v[2] = v[1];
+			v[1] = v[0];
+			v[0] = temp1 + temp2;
+		}
+
+		for (i = 0; i < 8; i++)
+			h[i] += v[i];
+
+	} while (in1 && in2);
+
+	va_end(ap);
+
+	uint32_t *out32 = (uint32_t*)out;
+	for (i = 0; i < 8; i++)
+		out32[i] = htonl(h[i]);
+}
diff --git a/src/sha256.h b/src/sha256.h
new file mode 100644
index 0000000..c6acadb
--- /dev/null
+++ b/src/sha256.h
@@ -0,0 +1,39 @@
+/*
+  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.
+*/
+
+
+#ifndef _FASTD_SHA256_H_
+#define _FASTD_SHA256_H_
+
+#include <stdint.h>
+
+
+#define FASTD_SHA256_HASH_BYTES 32
+#define FASTD_SHA256_HASH_BLOCK_BYTES 32
+
+
+void fastd_sha256_blocks(uint8_t out[FASTD_SHA256_HASH_BYTES], ...);
+
+#endif /* _FASTD_SHA256_H_ */