Nicely encapsulate different crypto algorithm implementations

1 files changed, 200 insertions, 0 deletions

diff --git a/src/crypto.c b/src/crypto.c
new file mode 100644
index 0000000..6aae261
--- /dev/null
+++ b/src/crypto.c
@@ -0,0 +1,200 @@
+/*
+  Copyright (c) 2012, 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"
+
+
+#ifdef USE_CRYPTO_AES128CTR
+#ifdef WITH_CRYPTO_AES128CTR_NACL
+
+#include <crypto_stream_aes128ctr.h>
+
+
+struct _fastd_crypto_aes128ctr_state {
+	fastd_buffer d;
+};
+
+
+static fastd_crypto_aes128ctr_context* aes128ctr_init(fastd_context *ctx) {
+	return (fastd_crypto_aes128ctr_context*)1;
+}
+
+static fastd_crypto_aes128ctr_state* aes128ctr_set_key(fastd_context *ctx, const fastd_crypto_aes128ctr_context *cctx, const fastd_block128 *key) {
+	fastd_crypto_aes128ctr_state *cstate = malloc(sizeof(fastd_crypto_aes128ctr_state));
+
+	cstate->d = fastd_buffer_alloc(crypto_stream_aes128ctr_BEFORENMBYTES, 0, 0);
+	crypto_stream_aes128ctr_beforenm(cstate->d.data, key->b);
+
+	return cstate;
+}
+
+static bool aes128ctr_crypt(fastd_context *ctx, const fastd_crypto_aes128ctr_state *cstate, fastd_block128 *out, const fastd_block128 *in, size_t len, const fastd_block128 *iv) {
+	crypto_stream_aes128ctr_xor_afternm(out->b, in->b, len, iv->b, cstate->d.data);
+	return true;
+}
+
+static void aes128ctr_free_state(fastd_context *ctx, fastd_crypto_aes128ctr_state *cstate) {
+	if (cstate) {
+		fastd_buffer_free(cstate->d);
+		free(cstate);
+	}
+}
+
+static void aes128ctr_free(fastd_context *ctx, fastd_crypto_aes128ctr_context *cctx) {
+}
+
+fastd_crypto_aes128ctr fastd_crypto_aes128ctr_nacl = {
+	.name = "nacl",
+
+	.init = aes128ctr_init,
+	.set_key = aes128ctr_set_key,
+	.crypt = aes128ctr_crypt,
+
+	.free_state = aes128ctr_free_state,
+	.free = aes128ctr_free,
+};
+
+#endif
+#endif
+
+#ifdef USE_CRYPTO_GHASH
+#ifdef WITH_CRYPTO_GHASH_BUILTIN
+
+struct _fastd_crypto_ghash_state {
+	fastd_block128 H[32][16];
+};
+
+
+static const fastd_block128 r = { .b = {0xe1} };
+
+
+static inline uint8_t shr(fastd_block128 *out, const fastd_block128 *in, int n) {
+	int i;
+	uint8_t c = 0;
+
+	for (i = 0; i < sizeof(fastd_block128); 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 *x, const fastd_crypto_ghash_state *cstate) {
+	fastd_block128 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_crypto_ghash_context* ghash_init(fastd_context *ctx) {
+	return (fastd_crypto_ghash_context*)1;
+}
+
+static fastd_crypto_ghash_state* ghash_set_h(fastd_context *ctx, const fastd_crypto_ghash_context *cctx, const fastd_block128 *h) {
+	fastd_crypto_ghash_state *cstate = malloc(sizeof(fastd_crypto_ghash_state));
+
+	fastd_block128 Hbase[4];
+	fastd_block128 Rbase[4];
+
+	Hbase[0] = *h;
+	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 R[16];
+	memset(cstate->H, 0, sizeof(cstate->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(&cstate->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(&cstate->H[i][j], &cstate->H[i-1][j], 4);
+			xor_a(&cstate->H[i][j], &R[carry]);
+		}
+	}
+
+	return cstate;
+}
+
+static bool ghash_hash(fastd_context *ctx, const fastd_crypto_ghash_state *cstate, fastd_block128 *out, const fastd_block128 *in, size_t n_blocks) {
+	memset(out, 0, sizeof(fastd_block128));
+
+	int i;
+	for (i = 0; i < n_blocks; i++) {
+		xor_a(out, &in[i]);
+		mulH_a(out, cstate);
+	}
+
+	return true;
+}
+
+static void ghash_free_state(fastd_context *ctx, fastd_crypto_ghash_state *cstate) {
+	free(cstate);
+}
+
+static void ghash_free(fastd_context *ctx, fastd_crypto_ghash_context *cctx) {
+}
+
+fastd_crypto_ghash fastd_crypto_ghash_builtin = {
+	.name = "builtin",
+
+	.init = ghash_init,
+	.set_h = ghash_set_h,
+	.hash = ghash_hash,
+
+	.free_state = ghash_free_state,
+	.free = ghash_free,
+};
+
+#endif
+#endif