Add "tiny" copy of the builtin ghash implementation

1 files changed, 147 insertions, 0 deletions

diff --git a/src/crypto/mac/ghash/tiny/ghash_tiny.c b/src/crypto/mac/ghash/tiny/ghash_tiny.c
new file mode 100644
index 0000000..f4a06b0
--- /dev/null
+++ b/src/crypto/mac/ghash/tiny/ghash_tiny.c
@@ -0,0 +1,147 @@
+/*
+  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"
+
+
+struct fastd_mac_state {
+	fastd_block128_t H[32][16];
+};
+
+
+static const fastd_block128_t r = { .b = {0xe1} };
+
+
+static inline uint8_t shr(fastd_block128_t *out, const fastd_block128_t *in, int n) {
+	size_t i;
+	uint8_t c = 0;
+
+	for (i = 0; i < sizeof(fastd_block128_t); i++) {
+		uint8_t c2 = in->b[i] << (8-n);
+		out->b[i] = (in->b[i] >> n) | c;
+		c = c2;
+	}
+
+	return (c >> (8-n));
+}
+
+static inline void mulH_a(fastd_block128_t *x, const fastd_mac_state_t *cstate) {
+	fastd_block128_t out = {};
+
+	int i;
+	for (i = 0; i < 16; i++) {
+		xor_a(&out, &cstate->H[2*i][x->b[i]>>4]);
+		xor_a(&out, &cstate->H[2*i+1][x->b[i]&0xf]);
+	}
+
+	*x = out;
+}
+
+
+static fastd_mac_context_t* ghash_initialize(fastd_context_t *ctx UNUSED) {
+	return NULL;
+}
+
+static size_t ghash_key_length(fastd_context_t *ctx UNUSED, const fastd_mac_context_t *cctx UNUSED) {
+	return sizeof(fastd_block128_t);
+}
+
+static fastd_mac_state_t* ghash_init_state(fastd_context_t *ctx UNUSED, const fastd_mac_context_t *mctx UNUSED, const uint8_t *key) {
+	fastd_mac_state_t *state = malloc(sizeof(fastd_mac_state_t));
+
+	fastd_block128_t Hbase[4];
+	fastd_block128_t Rbase[4];
+
+	memcpy(&Hbase[0], key, sizeof(fastd_block128_t));
+	Rbase[0] = r;
+
+	int i;
+	for (i = 1; i < 4; i++) {
+		uint8_t carry = shr(&Hbase[i], &Hbase[i-1], 1);
+		if (carry)
+			xor_a(&Hbase[i], &r);
+
+		shr(&Rbase[i], &Rbase[i-1], 1);
+	}
+
+	fastd_block128_t R[16];
+	memset(state->H, 0, sizeof(state->H));
+	memset(R, 0, sizeof(R));
+
+	for (i = 0; i < 16; i++) {
+		int j;
+		for (j = 0; j < 4; j++) {
+			if (i & (8 >> j)) {
+				xor_a(&state->H[0][i], &Hbase[j]);
+				xor_a(&R[i], &Rbase[j]);
+			}
+		}
+	}
+
+	for (i = 1; i < 32; i++) {
+		int j;
+
+		for (j = 0; j < 16; j++) {
+			uint8_t carry = shr(&state->H[i][j], &state->H[i-1][j], 4);
+			xor_a(&state->H[i][j], &R[carry]);
+		}
+	}
+
+	return state;
+}
+
+static bool ghash_hash(fastd_context_t *ctx UNUSED, const fastd_mac_state_t *state, fastd_block128_t *out, const fastd_block128_t *in, size_t n_blocks) {
+	memset(out, 0, sizeof(fastd_block128_t));
+
+	size_t i;
+	for (i = 0; i < n_blocks; i++) {
+		xor_a(out, &in[i]);
+		mulH_a(out, state);
+	}
+
+	return true;
+}
+
+static void ghash_free_state(fastd_context_t *ctx UNUSED, fastd_mac_state_t *state) {
+	free(state);
+}
+
+static void ghash_free(fastd_context_t *ctx UNUSED, fastd_mac_context_t *mctx UNUSED) {
+}
+
+const fastd_mac_t fastd_mac_ghash_tiny = {
+	.name = "tiny",
+
+	.initialize = ghash_initialize,
+
+	.key_length = ghash_key_length,
+	.init_state = ghash_init_state,
+
+	.hash = ghash_hash,
+
+	.free_state = ghash_free_state,
+	.free = ghash_free,
+};