aesni: Implement CMAC mode to provide a signer/prf

Compared to the cmac plugin using AESNI-CBC as backend, this improves
performance of AES-CMAC by ~45%.

src/libstrongswan/plugins/aesni/Makefile.am

@@ -18,6 +18,7 @@ libstrongswan_aesni_la_SOURCES = \
 	aesni_ctr.h aesni_ctr.c \
 	aesni_ccm.h aesni_ccm.c \
 	aesni_xcbc.h aesni_xcbc.c \
+	aesni_cmac.h aesni_cmac.c \
 	aesni_plugin.h aesni_plugin.c
 
 libstrongswan_aesni_la_LDFLAGS = -module -avoid-version

src/libstrongswan/plugins/aesni/aesni_cmac.c

@@ -0,0 +1,383 @@
+/*
+ * Copyright (C) 2012 Tobias Brunner
+ * Hochschule fuer Technik Rapperswil
+ * Copyright (C) 2015 Martin Willi
+ * Copyright (C) 2015 revosec AG
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License as published by the
+ * Free Software Foundation; either version 2 of the License, or (at your
+ * option) any later version.  See <http://www.fsf.org/copyleft/gpl.txt>.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
+ * or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+ * for more details.
+ */
+
+#include "aesni_cmac.h"
+#include "aesni_key.h"
+
+#include <crypto/prfs/mac_prf.h>
+#include <crypto/signers/mac_signer.h>
+
+typedef struct private_mac_t private_mac_t;
+
+/**
+ * Private data of a mac_t object.
+ */
+struct private_mac_t {
+
+	/**
+	 * Public interface.
+	 */
+	mac_t public;
+
+	/**
+	 * Key schedule for key K
+	 */
+	aesni_key_t *k;
+
+	/**
+	 * K1
+	 */
+	__m128i k1;
+
+	/**
+	 * K2
+	 */
+	__m128i k2;
+
+	/**
+	 * T
+	 */
+	__m128i t;
+
+	/**
+	 * remaining, unprocessed bytes in append mode
+	 */
+	u_char rem[AES_BLOCK_SIZE];
+
+	/**
+	 * number of bytes in remaining
+	 */
+	int rem_size;
+};
+
+METHOD(mac_t, get_mac, bool,
+	private_mac_t *this, chunk_t data, u_int8_t *out)
+{
+	__m128i k0, k1, k2, k3, k4, k5, k6, k7, k8, k9, k10;
+	__m128i t, l, *bi;
+	u_int blocks, rem, i;
+
+	if (!this->k)
+	{
+		return FALSE;
+	}
+
+	k0 = this->k->schedule[0];
+	k1 = this->k->schedule[1];
+	k2 = this->k->schedule[2];
+	k3 = this->k->schedule[3];
+	k4 = this->k->schedule[4];
+	k5 = this->k->schedule[5];
+	k6 = this->k->schedule[6];
+	k7 = this->k->schedule[7];
+	k8 = this->k->schedule[8];
+	k9 = this->k->schedule[9];
+	k10 = this->k->schedule[10];
+
+	t = this->t;
+
+	if (this->rem_size + data.len > AES_BLOCK_SIZE)
+	{
+		/* T := 0x00000000000000000000000000000000 (initially)
+		 * for each block M_i (except the last)
+		 *   X := T XOR M_i;
+		 *   T := AES-128(K, X);
+		 */
+
+		/* append data to remaining bytes, process block M_1 */
+		memcpy(this->rem + this->rem_size, data.ptr,
+			   AES_BLOCK_SIZE - this->rem_size);
+		data = chunk_skip(data, AES_BLOCK_SIZE - this->rem_size);
+
+		t = _mm_xor_si128(t, _mm_loadu_si128((__m128i*)this->rem));
+
+		t = _mm_xor_si128(t, k0);
+		t = _mm_aesenc_si128(t, k1);
+		t = _mm_aesenc_si128(t, k2);
+		t = _mm_aesenc_si128(t, k3);
+		t = _mm_aesenc_si128(t, k4);
+		t = _mm_aesenc_si128(t, k5);
+		t = _mm_aesenc_si128(t, k6);
+		t = _mm_aesenc_si128(t, k7);
+		t = _mm_aesenc_si128(t, k8);
+		t = _mm_aesenc_si128(t, k9);
+		t = _mm_aesenclast_si128(t, k10);
+
+		/* process blocks M_2 ... M_n-1 */
+		bi = (__m128i*)data.ptr;
+		rem = data.len % AES_BLOCK_SIZE;
+		blocks = data.len / AES_BLOCK_SIZE;
+		if (!rem && blocks)
+		{	/* don't do last block */
+			rem = AES_BLOCK_SIZE;
+			blocks--;
+		}
+
+		/* process blocks M[2] ... M[n-1] */
+		for (i = 0; i < blocks; i++)
+		{
+			t = _mm_xor_si128(t, _mm_loadu_si128(bi + i));
+
+			t = _mm_xor_si128(t, k0);
+			t = _mm_aesenc_si128(t, k1);
+			t = _mm_aesenc_si128(t, k2);
+			t = _mm_aesenc_si128(t, k3);
+			t = _mm_aesenc_si128(t, k4);
+			t = _mm_aesenc_si128(t, k5);
+			t = _mm_aesenc_si128(t, k6);
+			t = _mm_aesenc_si128(t, k7);
+			t = _mm_aesenc_si128(t, k8);
+			t = _mm_aesenc_si128(t, k9);
+			t = _mm_aesenclast_si128(t, k10);
+		}
+
+		/* store remaining bytes of block M_n */
+		memcpy(this->rem, data.ptr + data.len - rem, rem);
+		this->rem_size = rem;
+	}
+	else
+	{
+		/* no complete block (or last block), just copy into remaining */
+		memcpy(this->rem + this->rem_size, data.ptr, data.len);
+		this->rem_size += data.len;
+	}
+	if (out)
+	{
+		/* if last block is complete
+		 *   M_last := M_n XOR K1;
+		 * else
+		 *   M_last := padding(M_n) XOR K2;
+		 */
+		if (this->rem_size == AES_BLOCK_SIZE)
+		{
+			l = _mm_loadu_si128((__m128i*)this->rem);
+			l = _mm_xor_si128(l, this->k1);
+		}
+		else
+		{
+			/* padding(x) = x || 10^i  where i is 128-8*r-1
+			 * That is, padding(x) is the concatenation of x and a single '1',
+			 * followed by the minimum number of '0's, so that the total length is
+			 * equal to 128 bits.
+			 */
+			if (this->rem_size < AES_BLOCK_SIZE)
+			{
+				memset(this->rem + this->rem_size, 0,
+					   AES_BLOCK_SIZE - this->rem_size);
+				this->rem[this->rem_size] = 0x80;
+			}
+			l = _mm_loadu_si128((__m128i*)this->rem);
+			l = _mm_xor_si128(l, this->k2);
+		}
+		/* T := M_last XOR T;
+		 * T := AES-128(K,T);
+		 */
+		t = _mm_xor_si128(l, t);
+
+		t = _mm_xor_si128(t, k0);
+		t = _mm_aesenc_si128(t, k1);
+		t = _mm_aesenc_si128(t, k2);
+		t = _mm_aesenc_si128(t, k3);
+		t = _mm_aesenc_si128(t, k4);
+		t = _mm_aesenc_si128(t, k5);
+		t = _mm_aesenc_si128(t, k6);
+		t = _mm_aesenc_si128(t, k7);
+		t = _mm_aesenc_si128(t, k8);
+		t = _mm_aesenc_si128(t, k9);
+		t = _mm_aesenclast_si128(t, k10);
+
+		_mm_storeu_si128((__m128i*)out, t);
+
+		/* reset state */
+		t = _mm_setzero_si128();
+		this->rem_size = 0;
+	}
+	this->t = t;
+	return TRUE;
+}
+
+METHOD(mac_t, get_mac_size, size_t,
+	private_mac_t *this)
+{
+	return AES_BLOCK_SIZE;
+}
+
+/**
+ * Left-shift the given chunk by one bit.
+ */
+static void bit_shift(chunk_t chunk)
+{
+	size_t i;
+
+	for (i = 0; i < chunk.len; i++)
+	{
+		chunk.ptr[i] <<= 1;
+		if (i < chunk.len - 1 && chunk.ptr[i + 1] & 0x80)
+		{
+			chunk.ptr[i] |= 0x01;
+		}
+	}
+}
+
+METHOD(mac_t, set_key, bool,
+	private_mac_t *this, chunk_t key)
+{
+	__m128i rb, msb, l, a;
+	u_int round;
+	chunk_t k;
+
+	this->t = _mm_setzero_si128();
+	this->rem_size = 0;
+
+	/* we support variable keys as defined in RFC 4615 */
+	if (key.len == AES_BLOCK_SIZE)
+	{
+		k = key;
+	}
+	else
+	{	/* use cmac recursively to resize longer or shorter keys */
+		k = chunk_alloca(AES_BLOCK_SIZE);
+		memset(k.ptr, 0, k.len);
+		if (!set_key(this, k) || !get_mac(this, key, k.ptr))
+		{
+			return FALSE;
+		}
+	}
+
+	DESTROY_IF(this->k);
+	this->k = aesni_key_create(TRUE, k);
+	if (!this->k)
+	{
+		return FALSE;
+	}
+
+	/*
+	 * Rb = 0x00000000000000000000000000000087
+	 * L = 0x00000000000000000000000000000000 encrypted with K
+	 * if MSB(L) == 0
+	 *   K1 = L << 1
+	 * else
+	 *   K1 = (L << 1) XOR Rb
+	 * if MSB(K1) == 0
+	 *   K2 = K1 << 1
+	 * else
+	 *   K2 = (K1 << 1) XOR Rb
+	 */
+
+	rb = _mm_set_epi32(0x87000000, 0, 0, 0);
+	msb = _mm_set_epi32(0, 0, 0, 0x80);
+
+	l = _mm_setzero_si128();
+
+	l = _mm_xor_si128(l, this->k->schedule[0]);
+	for (round = 1; round < this->k->rounds; round++)
+	{
+		l = _mm_aesenc_si128(l, this->k->schedule[round]);
+	}
+	l = _mm_aesenclast_si128(l, this->k->schedule[this->k->rounds]);
+
+	this->k1 = l;
+	bit_shift(chunk_from_thing(this->k1));
+	a = _mm_and_si128(l, msb);
+	if (memchr(&a, 0x80, 1))
+	{
+		this->k1 = _mm_xor_si128(this->k1, rb);
+	}
+	this->k2 = this->k1;
+	bit_shift(chunk_from_thing(this->k2));
+	a = _mm_and_si128(this->k1, msb);
+	if (memchr(&a, 0x80, 1))
+	{
+		this->k2 = _mm_xor_si128(this->k2, rb);
+	}
+
+	return TRUE;
+}
+
+METHOD(mac_t, destroy, void,
+	private_mac_t *this)
+{
+	DESTROY_IF(this->k);
+	memwipe(&this->k1, sizeof(this->k1));
+	memwipe(&this->k2, sizeof(this->k2));
+	free(this);
+}
+
+/*
+ * Described in header
+ */
+mac_t *aesni_cmac_create(encryption_algorithm_t algo, size_t key_size)
+{
+	private_mac_t *this;
+
+	INIT(this,
+		.public = {
+			.get_mac = _get_mac,
+			.get_mac_size = _get_mac_size,
+			.set_key = _set_key,
+			.destroy = _destroy,
+		},
+	);
+
+	return &this->public;
+}
+
+/*
+ * Described in header.
+ */
+prf_t *aesni_cmac_prf_create(pseudo_random_function_t algo)
+{
+	mac_t *cmac;
+
+	switch (algo)
+	{
+		case PRF_AES128_CMAC:
+			cmac = aesni_cmac_create(ENCR_AES_CBC, 16);
+			break;
+		default:
+			return NULL;
+	}
+	if (cmac)
+	{
+		return mac_prf_create(cmac);
+	}
+	return NULL;
+}
+
+/*
+ * Described in header
+ */
+signer_t *aesni_cmac_signer_create(integrity_algorithm_t algo)
+{
+	size_t truncation;
+	mac_t *cmac;
+
+	switch (algo)
+	{
+		case AUTH_AES_CMAC_96:
+			cmac = aesni_cmac_create(ENCR_AES_CBC, 16);
+			truncation = 12;
+			break;
+		default:
+			return NULL;
+	}
+	if (cmac)
+	{
+		return mac_signer_create(cmac, truncation);
+	}
+	return NULL;
+}

src/libstrongswan/plugins/aesni/aesni_cmac.h

@@ -0,0 +1,52 @@
+/*
+ * Copyright (C) 2015 Martin Willi
+ * Copyright (C) 2015 revosec AG
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License as published by the
+ * Free Software Foundation; either version 2 of the License, or (at your
+ * option) any later version.  See <http://www.fsf.org/copyleft/gpl.txt>.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
+ * or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+ * for more details.
+ */
+
+/**
+ * @defgroup aesni_xcbc aesni_xcbc
+ * @{ @ingroup aesni
+ */
+
+#ifndef CMAC_H_
+#define CMAC_H_
+
+#include <crypto/mac.h>
+#include <crypto/prfs/prf.h>
+#include <crypto/signers/signer.h>
+
+/**
+ * Create a generic mac_t object using AESNI CMAC.
+ *
+ * @param algo		underlying encryption algorithm
+ * @param key_size	size of encryption key, in bytes
+ */
+mac_t *aesni_cmac_create(encryption_algorithm_t algo, size_t key_size);
+
+/**
+ * Creates a new prf_t object based AESNI CMAC.
+ *
+ * @param algo		algorithm to implement
+ * @return			prf_t object, NULL if not supported
+ */
+prf_t *aesni_cmac_prf_create(pseudo_random_function_t algo);
+
+/**
+ * Creates a new signer_t object based on AESNI CMAC.
+ *
+ * @param algo		algorithm to implement
+ * @return			signer_t, NULL if  not supported
+ */
+signer_t *aesni_cmac_signer_create(integrity_algorithm_t algo);
+
+#endif /** CMAC_H_ @}*/

src/libstrongswan/plugins/aesni/aesni_plugin.c

@@ -18,6 +18,7 @@
 #include "aesni_ctr.h"
 #include "aesni_ccm.h"
 #include "aesni_xcbc.h"
+#include "aesni_cmac.h"
 
 #include <stdio.h>
 
@@ -71,6 +72,10 @@ METHOD(plugin_t, get_features, int,
 			PLUGIN_PROVIDE(PRF, PRF_AES128_XCBC),
 		PLUGIN_REGISTER(SIGNER, aesni_xcbc_signer_create),
 			PLUGIN_PROVIDE(SIGNER, AUTH_AES_XCBC_96),
+		PLUGIN_REGISTER(PRF, aesni_cmac_prf_create),
+			PLUGIN_PROVIDE(PRF, PRF_AES128_CMAC),
+		PLUGIN_REGISTER(SIGNER, aesni_cmac_signer_create),
+			PLUGIN_PROVIDE(SIGNER, AUTH_AES_CMAC_96),
 	};
 
 	*features = f;