Add CCM alternative implementation

Add CCM HW accelerated alternative implementation

Author: Ron Eldor

features/mbedtls/targets/TARGET_CRYPTOCELL310/ccm_alt.c

@@ -0,0 +1,387 @@
+/*
+ *  ccm_alt.c
+ *
+ *  Copyright (C) 2018, ARM Limited, All Rights Reserved
+ *  SPDX-License-Identifier: Apache-2.0
+ *
+ *  Licensed under the Apache License, Version 2.0 (the "License"); you may
+ *  not use this file except in compliance with the License.
+ *  You may obtain a copy of the License at
+ *
+ *  http://www.apache.org/licenses/LICENSE-2.0
+ *
+ *  Unless required by applicable law or agreed to in writing, software
+ *  distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+ *  WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ *  See the License for the specific language governing permissions and
+ *  limitations under the License.
+ *
+ */
+
+#include "mbedtls/ccm.h"
+#if defined(MBEDTLS_CCM_ALT)
+#include <string.h>
+#include "mbedtls/platform.h"
+
+/* Implementation that should never be optimized out by the compiler */
+static void mbedtls_zeroize( void *v, size_t n ) {
+    volatile unsigned char *p = (unsigned char*)v;
+    while( n-- ) *p++ = 0;
+}
+
+#define CCM_ENCRYPT 0
+#define CCM_DECRYPT 1
+
+
+/*
+ * Macros for common operations.
+ * Results in smaller compiled code than static inline functions.
+ */
+
+/*
+ * Update the CBC-MAC state in y using a block in b
+ * (Always using b as the source helps the compiler optimise a bit better.)
+ */
+#define UPDATE_CBC_MAC                                                      \
+    for( i = 0; i < 16; i++ )                                               \
+        y[i] ^= b[i];                                                       \
+                                                                            \
+    if( ( ret = mbedtls_cipher_update( &ctx->cipher_ctx, y, 16, y, &olen ) ) != 0 ) \
+        return ( ret );
+
+/*
+ * Encrypt or decrypt a partial block with CTR
+ * Warning: using b for temporary storage! src and dst must not be b!
+ * This avoids allocating one more 16 bytes buffer while allowing src == dst.
+ */
+#define CTR_CRYPT( dst, src, len  )                                            \
+    if( ( ret = mbedtls_cipher_update( &ctx->cipher_ctx, ctr, 16, b, &olen ) ) != 0 )  \
+        return ( ret );                                                         \
+                                                                               \
+    for( i = 0; i < len; i++ )                                                 \
+        dst[i] = src[i] ^ b[i];
+
+void mbedtls_ccm_init( mbedtls_ccm_context *ctx )
+{
+    memset( ctx, 0, sizeof( mbedtls_ccm_context ) );
+}
+
+void mbedtls_ccm_free( mbedtls_ccm_context *ctx )
+{
+    mbedtls_zeroize( ctx, sizeof( mbedtls_ccm_context ) );
+}
+
+static int mbedtls_ccm_setkey_sw( mbedtls_ccm_sw_context *ctx,
+                        mbedtls_cipher_id_t cipher,
+                        const unsigned char *key,
+                        unsigned int keybits )
+{
+
+    int ret = 0;
+    const mbedtls_cipher_info_t *cipher_info = NULL;
+
+    cipher_info = mbedtls_cipher_info_from_values( cipher, keybits, MBEDTLS_MODE_ECB );
+    if( cipher_info == NULL )
+        return ( MBEDTLS_ERR_CCM_BAD_INPUT );
+
+    if( cipher_info->block_size != 16 )
+        return ( MBEDTLS_ERR_CCM_BAD_INPUT );
+
+    mbedtls_cipher_free( &ctx->cipher_ctx );
+
+    if( ( ret = mbedtls_cipher_setup( &ctx->cipher_ctx, cipher_info ) ) != 0 )
+        return ( ret );
+
+    return ( mbedtls_cipher_setkey( &ctx->cipher_ctx, key, keybits, MBEDTLS_ENCRYPT ) );
+}
+
+int mbedtls_ccm_setkey( mbedtls_ccm_context *ctx,
+                        mbedtls_cipher_id_t cipher,
+                        const unsigned char *key,
+                        unsigned int keybits )
+{
+    if( ctx == NULL )
+        return ( MBEDTLS_ERR_CCM_BAD_INPUT );
+
+    if( cipher != MBEDTLS_CIPHER_ID_AES ||
+         keybits != 128 )
+    {
+        ctx->is_sw = 1;
+        return ( mbedtls_ccm_setkey_sw( &ctx->u_ctx.ccm_sw_ctx, cipher, key, keybits ) );
+    }
+
+    ctx->is_sw = 0;
+
+    memcpy( ctx->u_ctx.ccm_alt_ctx.cipher_key , key, keybits/8 );
+    ctx->u_ctx.ccm_alt_ctx.keySize_ID = CRYS_AES_Key128BitSize;
+
+    return ( 0 );
+
+}
+
+/*
+ * Authenticated encryption or decryption
+ */
+static int ccm_auth_crypt_sw( mbedtls_ccm_sw_context *ctx, int mode, size_t length,
+                           const unsigned char *iv, size_t iv_len,
+                           const unsigned char *add, size_t add_len,
+                           const unsigned char *input, unsigned char *output,
+                           unsigned char *tag, size_t tag_len )
+{
+    int ret;
+    unsigned char i;
+    unsigned char q;
+    size_t len_left, olen;
+    unsigned char b[16];
+    unsigned char y[16];
+    unsigned char ctr[16];
+    const unsigned char *src;
+    unsigned char *dst;
+
+    if( add_len > 0xFF00 )
+        return ( MBEDTLS_ERR_CCM_BAD_INPUT );
+
+    q = 16 - 1 - (unsigned char) iv_len;
+
+    /*
+     * First block B_0:
+     * 0        .. 0        flags
+     * 1        .. iv_len   nonce (aka iv)
+     * iv_len+1 .. 15       length
+     *
+     * With flags as (bits):
+     * 7        0
+     * 6        add present?
+     * 5 .. 3   (t - 2) / 2
+     * 2 .. 0   q - 1
+     */
+    b[0] = 0;
+    b[0] |= ( add_len > 0 ) << 6;
+    b[0] |= ( ( tag_len - 2 ) / 2 ) << 3;
+    b[0] |= q - 1;
+
+    memcpy( b + 1, iv, iv_len );
+
+    for( i = 0, len_left = length; i < q; i++, len_left >>= 8 )
+        b[15-i] = (unsigned char)( len_left & 0xFF );
+
+    if( len_left > 0 )
+        return ( MBEDTLS_ERR_CCM_BAD_INPUT );
+
+
+    /* Start CBC-MAC with first block */
+    memset( y, 0, 16 );
+    UPDATE_CBC_MAC;
+
+    /*
+     * If there is additional data, update CBC-MAC with
+     * add_len, add, 0 (padding to a block boundary)
+     */
+    if( add_len > 0 )
+    {
+        size_t use_len;
+        len_left = add_len;
+        src = add;
+
+        memset( b, 0, 16 );
+        b[0] = (unsigned char)( ( add_len >> 8 ) & 0xFF );
+        b[1] = (unsigned char)( ( add_len      ) & 0xFF );
+
+        use_len = len_left < 16 - 2 ? len_left : 16 - 2;
+        memcpy( b + 2, src, use_len );
+        len_left -= use_len;
+        src += use_len;
+
+        UPDATE_CBC_MAC;
+        while( len_left > 0 )
+        {
+            use_len = len_left > 16 ? 16 : len_left;
+
+            memset( b, 0, 16 );
+            memcpy( b, src, use_len );
+            UPDATE_CBC_MAC;
+
+            len_left -= use_len;
+            src += use_len;
+        }
+    }
+
+    /*
+     * Prepare counter block for encryption:
+     * 0        .. 0        flags
+     * 1        .. iv_len   nonce (aka iv)
+     * iv_len+1 .. 15       counter (initially 1)
+     *
+     * With flags as (bits):
+     * 7 .. 3   0
+     * 2 .. 0   q - 1
+     */
+    ctr[0] = q - 1;
+    memcpy( ctr + 1, iv, iv_len );
+    memset( ctr + 1 + iv_len, 0, q );
+    ctr[15] = 1;
+
+    /*
+     * Authenticate and {en,de}crypt the message.
+     *
+     * The only difference between encryption and decryption is
+     * the respective order of authentication and {en,de}cryption.
+     */
+    len_left = length;
+    src = input;
+    dst = output;
+
+    while( len_left > 0 )
+    {
+        size_t use_len = len_left > 16 ? 16 : len_left;
+
+        if( mode == CCM_ENCRYPT )
+        {
+            memset( b, 0, 16 );
+            memcpy( b, src, use_len );
+            UPDATE_CBC_MAC;
+        }
+
+        CTR_CRYPT( dst, src, use_len );
+
+        if( mode == CCM_DECRYPT )
+        {
+            memset( b, 0, 16 );
+            memcpy( b, dst, use_len );
+            UPDATE_CBC_MAC;
+        }
+
+        dst += use_len;
+        src += use_len;
+        len_left -= use_len;
+
+        /*
+         * Increment counter.
+         * No need to check for overflow thanks to the length check above.
+         */
+        for( i = 0; i < q; i++ )
+            if( ++ctr[15-i] != 0 )
+                break;
+    }
+
+    /*
+     * Authentication: reset counter and crypt/mask internal tag
+     */
+    for( i = 0; i < q; i++ )
+        ctr[15-i] = 0;
+
+    CTR_CRYPT( y, y, 16 );
+    memcpy( tag, y, tag_len );
+
+    return ( 0 );
+}
+
+int mbedtls_ccm_encrypt_and_tag( mbedtls_ccm_context *ctx, size_t length,
+                         const unsigned char *iv, size_t iv_len,
+                         const unsigned char *add, size_t add_len,
+                         const unsigned char *input, unsigned char *output,
+                         unsigned char *tag, size_t tag_len )
+
+{
+    CRYSError_t CrysRet = CRYS_OK;
+    /*
+     * Check length requirements: SP800-38C A.1
+     * Additional requirement: a < 2^16 - 2^8 to simplify the code.
+     * 'length' checked later (when writing it to the first block)
+     */
+    if( tag_len < 4 || tag_len > 16 || tag_len % 2 != 0 )
+        return ( MBEDTLS_ERR_CCM_BAD_INPUT );
+
+    /* Also implies q is within bounds */
+    if( iv_len < 7 || iv_len > 13 )
+        return ( MBEDTLS_ERR_CCM_BAD_INPUT );
+
+    if( ctx->is_sw )
+        return ( ccm_auth_crypt_sw( &ctx->u_ctx.ccm_sw_ctx, CCM_ENCRYPT,  length, iv, iv_len,
+                                                     add, add_len, input, output,
+                                                     tag, tag_len ) );
+
+    if( length > 0xFFFFFFFF || add_len > 0xFFFFFFFF )
+        return ( MBEDTLS_ERR_CCM_BAD_INPUT );
+
+    CrysRet =  CRYS_AESCCM( SASI_AES_ENCRYPT, ctx->u_ctx.ccm_alt_ctx.cipher_key, ctx->u_ctx.ccm_alt_ctx.keySize_ID,
+                   (uint8_t*)iv, iv_len,  (uint8_t*)add, add_len,  (uint8_t*)input, length, output, tag_len, tag );
+    if( CrysRet != CRYS_OK )
+        return ( MBEDTLS_ERR_CCM_HW_ACCEL_FAILED );
+
+    return ( 0 );
+
+}
+
+/*
+ * Authenticated decryption
+ */
+static int mbedtls_ccm_auth_decrypt_sw( mbedtls_ccm_sw_context *ctx, size_t length,
+                      const unsigned char *iv, size_t iv_len,
+                      const unsigned char *add, size_t add_len,
+                      const unsigned char *input, unsigned char *output,
+                      const unsigned char *tag, size_t tag_len )
+{
+    int ret;
+    unsigned char check_tag[16];
+    unsigned char i;
+    int diff;
+
+    if( ( ret = ccm_auth_crypt_sw( ctx, CCM_DECRYPT, length,
+                                        iv, iv_len, add, add_len,
+                                        input, output, check_tag, tag_len ) ) != 0 )
+    {
+        return ( ret );
+    }
+
+    /* Check tag in "constant-time" */
+    for( diff = 0, i = 0; i < tag_len; i++ )
+        diff |= tag[i] ^ check_tag[i];
+
+    if( diff != 0 )
+    {
+        mbedtls_zeroize( output, length );
+        return ( MBEDTLS_ERR_CCM_AUTH_FAILED );
+    }
+
+    return ( 0 );
+}
+
+int mbedtls_ccm_auth_decrypt( mbedtls_ccm_context *ctx, size_t length,
+                      const unsigned char *iv, size_t iv_len,
+                      const unsigned char *add, size_t add_len,
+                      const unsigned char *input, unsigned char *output,
+                      const unsigned char *tag, size_t tag_len )
+
+{
+    CRYSError_t CrysRet = CRYS_OK;
+    /*
+     * Check length requirements: SP800-38C A.1
+     * Additional requirement: a < 2^16 - 2^8 to simplify the code.
+     * 'length' checked later (when writing it to the first block)
+     */
+    if( tag_len < 4 || tag_len > 16 || tag_len % 2 != 0 )
+        return ( MBEDTLS_ERR_CCM_BAD_INPUT );
+
+    /* Also implies q is within bounds */
+    if( iv_len < 7 || iv_len > 13 )
+        return ( MBEDTLS_ERR_CCM_BAD_INPUT );
+
+    if ( ctx->is_sw )
+        return ( mbedtls_ccm_auth_decrypt_sw( &ctx->u_ctx.ccm_sw_ctx, length, iv, iv_len,
+                                                  add, add_len, input, output,
+                                                  tag, tag_len ) );
+
+    if( length > 0xFFFFFFFF || add_len > 0xFFFFFFFF )
+        return ( MBEDTLS_ERR_CCM_BAD_INPUT );
+
+    CrysRet =  CRYS_AESCCM( SASI_AES_DECRYPT, ctx->u_ctx.ccm_alt_ctx.cipher_key, ctx->u_ctx.ccm_alt_ctx.keySize_ID,
+                         (uint8_t*)iv, iv_len,  (uint8_t*)add, add_len,  (uint8_t*)input, length, output, tag_len, (uint8_t*)tag );
+    if ( CrysRet != CRYS_OK )
+        return ( MBEDTLS_ERR_CCM_HW_ACCEL_FAILED );
+
+    return ( 0 );
+
+}
+
+#endif