[U-Boot] [PATCH 03/14] tegra: Add crypto library for warmboot code

[Simon Glass <sjg@chromium.org>]

From: Yen Lin <yelin@nvidia.com>

Provides an interface to aes.c for the warmboot code.

Signed-off-by: Simon Glass <sjg@chromium.org>
---
 arch/arm/cpu/armv7/tegra2/crypto.c |  234 ++++++++++++++++++++++++++++++++++++
 arch/arm/cpu/armv7/tegra2/crypto.h |   36 ++++++
 2 files changed, 270 insertions(+), 0 deletions(-)
 create mode 100644 arch/arm/cpu/armv7/tegra2/crypto.c
 create mode 100644 arch/arm/cpu/armv7/tegra2/crypto.h

diff --git a/arch/arm/cpu/armv7/tegra2/crypto.c b/arch/arm/cpu/armv7/tegra2/crypto.c
new file mode 100644
index 0000000..563ce6b
--- /dev/null
+++ b/arch/arm/cpu/armv7/tegra2/crypto.c
@@ -0,0 +1,234 @@
+/*
+ * Copyright (c) 2011 The Chromium OS Authors.
+ * (C) Copyright 2010 - 2011 NVIDIA Corporation <www.nvidia.com>
+ *
+ * See file CREDITS for list of people who contributed to this
+ * project.
+ *
+ * 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.
+ *
+ * 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.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston,
+ * MA 02111-1307 USA
+ */
+
+#include <common.h>
+#include <asm/errno.h>
+#include "crypto.h"
+#include "aes.h"
+
+static u8 zero_key[16];
+
+#define AES_CMAC_CONST_RB 0x87  /* from RFC 4493, Figure 2.2 */
+
+enum security_op {
+	SECURITY_SIGN		= 1 << 0,	/* Sign the data */
+	SECURITY_ENCRYPT	= 1 << 1,	/* Encrypt the data */
+};
+
+#ifdef DEBUG
+static void debug_print_vector(char *name, u32 num_bytes, u8 *data)
+{
+	u32 i;
+
+	printf("%s [%d] @0x%08x", name, num_bytes, (u32)data);
+	for (i = 0; i < num_bytes; i++) {
+		if (i % 16 == 0)
+			printf(" = ");
+		printf("%02x", data[i]);
+		if ((i+1) % 16 != 0)
+			printf(" ");
+	}
+	printf("\n");
+}
+#else
+#define debug_print_vector(name, num_bytes, data)
+#endif
+
+/**
+ * Apply chain data to the destination using EOR
+ *
+ * Each array is of length AES_AES_KEY_LENGTH.
+ *
+ * \param cbc_chain_data	Chain data
+ * \param src			Source data
+ * \param dst			Destination data, which is modified here
+ */
+static void apply_cbc_chain_data(u8 *cbc_chain_data, u8 *src, u8 *dst)
+{
+	int i;
+
+	for (i = 0; i < 16; i++)
+		*dst++ = *src++ ^ *cbc_chain_data++;
+}
+
+/**
+ * Encrypt some data with AES.
+ *
+ * \param key_schedule		Expanded key to use
+ * \param src			Source data to encrypt
+ * \param dst			Destination buffer
+ * \param num_aes_blocks	Number of AES blocks to encrypt
+ */
+static void encrypt_object(u8 *key_schedule, u8 *src, u8 *dst,
+			   u32 num_aes_blocks)
+{
+	u8 tmp_data[AES_KEY_LENGTH];
+	u8 *cbc_chain_data;
+	u32 i;
+
+	cbc_chain_data = zero_key;	/* Convenient array of 0's for IV */
+
+	for (i = 0; i < num_aes_blocks; i++) {
+		debug("encrypt_object: block %d of %d\n", i, num_aes_blocks);
+		debug_print_vector("AES Src", AES_KEY_LENGTH, src);
+
+		/* Apply the chain data */
+		apply_cbc_chain_data(cbc_chain_data, src, tmp_data);
+		debug_print_vector("AES Xor", AES_KEY_LENGTH, tmp_data);
+
+		/* encrypt the AES block */
+		aes_encrypt(tmp_data, key_schedule, dst);
+		debug_print_vector("AES Dst", AES_KEY_LENGTH, dst);
+
+		/* Update pointers for next loop. */
+		cbc_chain_data = dst;
+		src += AES_KEY_LENGTH;
+		dst += AES_KEY_LENGTH;
+	}
+}
+
+/**
+ * Shift a vector left by one bit
+ *
+ * \param in	Input vector
+ * \param out	Output vector
+ * \param size	Length of vector in bytes
+ */
+static void left_shift_vector(u8 *in, u8 *out, int size)
+{
+	int carry = 0;
+	int i;
+
+	for (i = size - 1; i >= 0; i--) {
+		out[i] = (in[i] << 1) | carry;
+		carry = in[i] >> 7;	/* get most significant bit */
+	}
+}
+
+/**
+ * Sign a block of data, putting the result into dst.
+ *
+ * \param key			Input AES key, length AES_KEY_LENGTH
+ * \param key_schedule		Expanded key to use
+ * \param src			Source data of length 'num_aes_blocks' blocks
+ * \param dst			Destination buffer, length AES_KEY_LENGTH
+ * \param num_aes_blocks	Number of AES blocks to encrypt
+ */
+static void sign_object(u8 *key, u8 *key_schedule, u8 *src, u8 *dst,
+			u32 num_aes_blocks)
+{
+	u8 tmp_data[AES_KEY_LENGTH];
+	u8 left[AES_KEY_LENGTH];
+	u8 k1[AES_KEY_LENGTH];
+	u8 *cbc_chain_data;
+	unsigned i;
+
+	cbc_chain_data = zero_key;	/* Convenient array of 0's for IV */
+
+	/* compute K1 constant needed by AES-CMAC calculation */
+	for (i = 0; i < AES_KEY_LENGTH; i++)
+		tmp_data[i] = 0;
+
+	encrypt_object(key_schedule, tmp_data, left, 1);
+	debug_print_vector("AES(key, nonce)", AES_KEY_LENGTH, left);
+
+	left_shift_vector(left, k1, sizeof(left));
+	debug_print_vector("L", AES_KEY_LENGTH, left);
+
+	if ((left[0] >> 7) != 0) /* get MSB of L */
+		k1[AES_KEY_LENGTH-1] ^= AES_CMAC_CONST_RB;
+	debug_print_vector("K1", AES_KEY_LENGTH, k1);
+
+	/* compute the AES-CMAC value */
+	for (i = 0; i < num_aes_blocks; i++) {
+		/* Apply the chain data */
+		apply_cbc_chain_data(cbc_chain_data, src, tmp_data);
+
+		/* for the final block, XOR K1 into the IV */
+		if (i == num_aes_blocks - 1)
+			apply_cbc_chain_data(tmp_data, k1, tmp_data);
+
+		/* encrypt the AES block */
+		aes_encrypt(tmp_data, key_schedule, dst);
+
+		debug("sign_obj: block %d of %d\n", i, num_aes_blocks);
+		debug_print_vector("AES-CMAC Src", AES_KEY_LENGTH, src);
+		debug_print_vector("AES-CMAC Xor", AES_KEY_LENGTH, tmp_data);
+		debug_print_vector("AES-CMAC Dst", AES_KEY_LENGTH, dst);
+
+		/* Update pointers for next loop. */
+		cbc_chain_data = dst;
+		src += AES_KEY_LENGTH;
+	}
+
+	debug_print_vector("AES-CMAC Hash", AES_KEY_LENGTH, dst);
+}
+
+/**
+ * Encrypt and sign a block of data (depending on security mode).
+ *
+ * \param key		Input AES key, length AES_KEY_LENGTH
+ * \param oper		Security operations mask to perform (enum security_op)
+ * \param src		Source data
+ * \param length	Size of source data
+ * \param sig_dst	Destination address for signature, AES_KEY_LENGTH bytes
+ */
+static int encrypt_and_sign(u8 *key, enum security_op oper, u8 *src,
+			    u32 length, u8 *sig_dst)
+{
+	u32 num_aes_blocks;
+	u8 key_schedule[AES_EXPAND_KEY_LENGTH];
+
+	debug("encrypt_and_sign: length = %d\n", length);
+	debug_print_vector("AES key", AES_KEY_LENGTH, key);
+
+	/*
+	 * The only need for a key is for signing/checksum purposes, so
+	 * if not encrypting, expand a key of 0s.
+	 */
+	aes_expand_key(oper & SECURITY_ENCRYPT ? key : zero_key, key_schedule);
+
+	num_aes_blocks = (length + AES_KEY_LENGTH - 1) / AES_KEY_LENGTH;
+
+	if (oper & SECURITY_ENCRYPT) {
+		/* Perform this in place, resulting in src being encrypted. */
+		debug("encrypt_and_sign: begin encryption\n");
+		encrypt_object(key_schedule, src, src, num_aes_blocks);
+		debug("encrypt_and_sign: end encryption\n");
+	}
+
+	if (oper & SECURITY_SIGN) {
+		/* encrypt the data, overwriting the result in signature. */
+		debug("encrypt_and_sign: begin signing\n");
+		sign_object(key, key_schedule, src, sig_dst, num_aes_blocks);
+		debug("encrypt_and_sign: end signing\n");
+	}
+
+	return 0;
+}
+
+int sign_data_block(u8 *source, unsigned length, u8 *signature)
+{
+	return encrypt_and_sign(zero_key, SECURITY_SIGN, source,
+				length, signature);
+}
diff --git a/arch/arm/cpu/armv7/tegra2/crypto.h b/arch/arm/cpu/armv7/tegra2/crypto.h
new file mode 100644
index 0000000..aff67e7
--- /dev/null
+++ b/arch/arm/cpu/armv7/tegra2/crypto.h
@@ -0,0 +1,36 @@
+/*
+ * Copyright (c) 2011 The Chromium OS Authors.
+ * (C) Copyright 2010 - 2011 NVIDIA Corporation <www.nvidia.com>
+ *
+ * See file CREDITS for list of people who contributed to this
+ * project.
+ *
+ * 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.
+ *
+ * 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.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston,
+ * MA 02111-1307 USA
+ */
+
+#ifndef _CRYPTO_H_
+#define _CRYPTO_H_
+
+/**
+ * Sign a block of data
+ *
+ * \param source	Source data
+ * \param length	Size of source data
+ * \param signature	Destination address for signature, AES_KEY_LENGTH bytes
+ */
+int sign_data_block(u8 *source, unsigned length, u8 *signature);
+
+#endif /* #ifndef _CRYPTO_H_ */
-- 
1.7.3.1