/**
* \file poly1305.c
*
* \brief Poly1305 authentication algorithm.
*
* Copyright (C) 2006-2016, 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.
*
* This file is part of mbed TLS (https://tls.mbed.org)
*/
#if !defined(MBEDTLS_CONFIG_FILE)
#include "mbedtls/config.h"
#else
#include MBEDTLS_CONFIG_FILE
#endif
#if defined(MBEDTLS_POLY1305_C)
#include "mbedtls/poly1305.h"
#include "mbedtls/platform_util.h"
#include "mbedtls/error.h"
#include <string.h>
#if defined(MBEDTLS_SELF_TEST)
#if defined(MBEDTLS_PLATFORM_C)
#include "mbedtls/platform.h"
#else
#include <stdio.h>
#define mbedtls_printf printf
#endif /* MBEDTLS_PLATFORM_C */
#endif /* MBEDTLS_SELF_TEST */
#if !defined(MBEDTLS_POLY1305_ALT)
#if ( defined(__ARMCC_VERSION) || defined(_MSC_VER) ) && \
!defined(inline) && !defined(__cplusplus)
#define inline __inline
#endif
/* Parameter validation macros */
#define POLY1305_VALIDATE_RET( cond ) \
MBEDTLS_INTERNAL_VALIDATE_RET( cond, MBEDTLS_ERR_POLY1305_BAD_INPUT_DATA )
#define POLY1305_VALIDATE( cond ) \
MBEDTLS_INTERNAL_VALIDATE( cond )
#define POLY1305_BLOCK_SIZE_BYTES ( 16U )
#define BYTES_TO_U32_LE( data, offset ) \
( (uint32_t) (data)[offset] \
| (uint32_t) ( (uint32_t) (data)[( offset ) + 1] << 8 ) \
| (uint32_t) ( (uint32_t) (data)[( offset ) + 2] << 16 ) \
| (uint32_t) ( (uint32_t) (data)[( offset ) + 3] << 24 ) \
)
/*
* Our implementation is tuned for 32-bit platforms with a 64-bit multiplier.
* However we provided an alternative for platforms without such a multiplier.
*/
#if defined(MBEDTLS_NO_64BIT_MULTIPLICATION)
static uint64_t mul64( uint32_t a, uint32_t b )
{
/* a = al + 2**16 ah, b = bl + 2**16 bh */
const uint16_t al = (uint16_t) a;
const uint16_t bl = (uint16_t) b;
const uint16_t ah = a >> 16;
const uint16_t bh = b >> 16;
/* ab = al*bl + 2**16 (ah*bl + bl*bh) + 2**32 ah*bh */
const uint32_t lo = (uint32_t) al * bl;
const uint64_t me = (uint64_t)( (uint32_t) ah * bl ) + (uint32_t) al * bh;
const uint32_t hi = (uint32_t) ah * bh;
return( lo + ( me << 16 ) + ( (uint64_t) hi << 32 ) );
}
#else
static inline uint64_t mul64( uint32_t a, uint32_t b )
{
return( (uint64_t) a * b );
}
#endif
/**
* \brief Process blocks with Poly1305.
*
* \param ctx The Poly1305 context.
* \param nblocks Number of blocks to process. Note that this
* function only processes full blocks.
* \param input Buffer containing the input block(s).
* \param needs_padding Set to 0 if the padding bit has already been
* applied to the input data before calling this
* function. Otherwise, set this parameter to 1.
*/
static void poly1305_process( mbedtls_poly1305_context *ctx,
size_t nblocks,
const unsigned char *input,
uint32_t needs_padding )
{
uint64_t d0, d1, d2, d3;
uint32_t acc0, acc1, acc2, acc3, acc4;
uint32_t r0, r1, r2, r3;
uint32_t rs1, rs2, rs3;
size_t offset = 0U;
size_t i;
r0 = ctx->r[0];
r1 = ctx->r[1];
r2 = ctx->r[2];
r3 = ctx->r[3];
rs1 = r1 + ( r1 >> 2U );
rs2 = r2 + ( r2 >> 2U );
rs3 = r3 + ( r3 >> 2U );
acc0 = ctx->acc[0];
acc1 = ctx->acc[1];
acc2 = ctx->acc[2];
acc3 = ctx->acc[3];
acc4 = ctx->acc[4];
/* Process full blocks */
for( i = 0U; i < nblocks; i++ )
{
/* The input block is treated as a 128-bit little-endian integer */
d0 = BYTES_TO_U32_LE( input, offset + 0 );
d1 = BYTES_TO_U32_LE( input, offset + 4 );
d2 = BYTES_TO_U32_LE( input, offset + 8 );
d3 = BYTES_TO_U32_LE( input, offset + 12 );
/* Compute: acc += (padded) block as a 130-bit integer */
d0 += (uint64_t) acc0;
d1 += (uint64_t) acc1 + ( d0 >> 32U );
d2 += (uint64_t) acc2 + ( d1 >> 32U );
d3 += (uint64_t) acc3 + ( d2 >> 32U );
acc0 = (uint32_t) d0;
acc1 = (uint32_t) d1;
acc2 = (uint32_t) d2;
acc3 = (uint32_t) d3;
acc4 += (uint32_t) ( d3 >> 32U ) + needs_padding;
/* Compute: acc *= r */
d0 = mul64( acc0, r0 ) +
mul64( acc1, rs3 ) +
mul64( acc2, rs2 ) +
mul64( acc3, rs1 );
d1 = mul64( acc0, r1 ) +
mul64( acc1, r0 ) +
mul64( acc2, rs3 ) +
mul64( acc3, rs2 ) +
mul64( acc4, rs1 );
d2 = mul64( acc0, r2 ) +
mul64( acc1, r1 ) +
mul64( acc2, r0 ) +
mul64( acc3, rs3 ) +
mul64( acc4, rs2 );
d3 = mul64( acc0, r3 ) +
mul64( acc1, r2 ) +
mul64( acc2, r1 ) +
mul64( acc3, r0 ) +
mul64( acc4, rs3 );
acc4 *= r0;
/* Compute: acc %= (2^130 - 5) (partial remainder) */
d1 += ( d0 >> 32 );
d2 += ( d1 >> 32 );
d3 += ( d2 >> 32 );
acc0 = (uint32_t) d0;
acc1 = (uint32_t) d1;
acc2 = (uint32_t) d2;
acc3 = (uint32_t) d3;
acc4 = (uint32_t) ( d3 >> 32 ) + acc4;
d0 = (uint64_t) acc0 + ( acc4 >> 2 ) + ( acc4 & 0xFFFFFFFCU );
acc4 &= 3U;
acc0 = (uint32_t) d0;
d0 = (uint64_t) acc1 + ( d0 >> 32U );
acc1 = (uint32_t) d0;
d0 = (uint64_t) acc2 + ( d0 >> 32U );
acc2 = (uint32_t) d0;
d0 = (uint64_t) acc3 + ( d0 >> 32U );
acc3 = (uint32_t) d0;
d0 = (uint64_t) acc4 + ( d0 >> 32U );
acc4 = (uint32_t) d0;
offset += POLY1305_BLOCK_SIZE_BYTES;
}
ctx->acc[0] = acc0;
ctx->acc[1] = acc1;
ctx->acc[2] = acc2;
ctx->acc[3] = acc3;
ctx->acc[4] = acc4;
}
/**
* \brief Compute the Poly1305 MAC
*
* \param ctx The Poly1305 context.
* \param mac The buffer to where the MAC is written. Must be
* big enough to contain the 16-byte MAC.
*/
static void poly1305_compute_mac( const mbedtls_poly1305_context *ctx,
unsigned char mac[16] )
{
uint64_t d;
uint32_t g0, g1, g2, g3, g4;
uint32_t acc0, acc1, acc2, acc3, acc4;
uint32_t mask;
uint32_t mask_inv;
acc0 = ctx->acc[0];
acc1 = ctx->acc[1];
acc2 = ctx->acc[2];
acc3 = ctx->acc[3];
acc4 = ctx->acc[4];
/* Before adding 's' we ensure that the accumulator is mod 2^130 - 5.
* We do this by calculating acc - (2^130 - 5), then checking if
* the 131st bit is set. If it is, then reduce: acc -= (2^130 - 5)
*/
/* Calculate acc + -(2^130 - 5) */
d = ( (uint64_t) acc0 + 5U );
g0 = (uint32_t) d;
d = ( (uint64_t) acc1 + ( d >> 32 ) );
g1 = (uint32_t) d;
d = ( (uint64_t) acc2 + ( d >> 32 ) );
g2 = (uint32_t) d;
d = ( (uint64_t) acc3 + ( d >> 32 ) );
g3 = (uint32_t) d;
g4 = acc4 + (uint32_t) ( d >> 32U );
/* mask == 0xFFFFFFFF if 131st bit is set, otherwise mask == 0 */
mask = (uint32_t) 0U - ( g4 >> 2U );
mask_inv = ~mask;
/* If 131st bit is set then acc=g, otherwise, acc is unmodified */
acc0 = ( acc0 & mask_inv ) | ( g0 & mask );
acc1 = ( acc1 & mask_inv ) | ( g1 & mask );
acc2 = ( acc2 & mask_inv ) | ( g2 & mask );
acc3 = ( acc3 & mask_inv ) | ( g3 & mask );
/* Add 's' */
d = (uint64_t) acc0 + ctx->s[0];
acc0 = (uint32_t) d;
d = (uint64_t) acc1 + ctx->s[1] + ( d >> 32U );
acc1 = (uint32_t) d;
d = (uint64_t) acc2 + ctx->s[2] + ( d >> 32U );
acc2 = (uint32_t) d;
acc3 += ctx->s[3] + (uint32_t) ( d >> 32U );
/* Compute MAC (128 least significant bits of the accumulator) */
mac[ 0] = (unsigned char)( acc0 );
mac[ 1] = (unsigned char)( acc0 >> 8 );
mac[ 2] = (unsigned char)( acc0 >> 16 );
mac[ 3] = (unsigned char)( acc0 >> 24 );
mac[ 4] = (unsigned char)( acc1 );
mac[ 5] = (unsigned char)( acc1 >> 8 );
mac[ 6] = (unsigned char)( acc1 >> 16 );
mac[ 7] = (unsigned char)( acc1 >> 24 );
mac[ 8] = (unsigned char)( acc2 );
mac[ 9] = (unsigned char)( acc2 >> 8 );
mac[10] = (unsigned char)( acc2 >> 16 );
mac[11] = (unsigned char)( acc2 >> 24 );
mac[12] = (unsigned char)( acc3 );
mac[13] = (unsigned char)( acc3 >> 8 );
mac[14] = (unsigned char)( acc3 >> 16 );
mac[15] = (unsigned char)( acc3 >> 24 );
}
void mbedtls_poly1305_init( mbedtls_poly1305_context *ctx )
{
POLY1305_VALIDATE( ctx != NULL );
mbedtls_platform_zeroize( ctx, sizeof( mbedtls_poly1305_context ) );
}
void mbedtls_poly1305_free( mbedtls_poly1305_context *ctx )
{
if( ctx == NULL )
return;
mbedtls_platform_zeroize( ctx, sizeof( mbedtls_poly1305_context ) );
}
int mbedtls_poly1305_starts( mbedtls_poly1305_context *ctx,
const unsigned char key[32] )
{
POLY1305_VALIDATE_RET( ctx != NULL );
POLY1305_VALIDATE_RET( key != NULL );
/* r &= 0x0ffffffc0ffffffc0ffffffc0fffffff */
ctx->r[0] = BYTES_TO_U32_LE( key, 0 ) & 0x0FFFFFFFU;
ctx->r[1] = BYTES_TO_U32_LE( key, 4 ) & 0x0FFFFFFCU;
ctx->r[2] = BYTES_TO_U32_LE( key, 8 ) & 0x0FFFFFFCU;
ctx->r[3] = BYTES_TO_U32_LE( key, 12 ) & 0x0FFFFFFCU;
ctx->s[0] = BYTES_TO_U32_LE( key, 16 );
ctx->s[1] = BYTES_TO_U32_LE( key, 20 );
ctx->s[2] = BYTES_TO_U32_LE( key, 24 );
ctx->s[3] = BYTES_TO_U32_LE( key, 28 );
/* Initial accumulator state */
ctx->acc[0] = 0U;
ctx->acc[1] = 0U;
ctx->acc[2] = 0U;
ctx->acc[3] = 0U;
ctx->acc[4] = 0U;
/* Queue initially empty */
mbedtls_platform_zeroize( ctx->queue, sizeof( ctx->queue ) );
ctx->queue_len = 0U;
return( 0 );
}
int mbedtls_poly1305_update( mbedtls_poly1305_context *ctx,
const unsigned char *input,
size_t ilen )
{
size_t offset = 0U;
size_t remaining = ilen;
size_t queue_free_len;
size_t nblocks;
POLY1305_VALIDATE_RET( ctx != NULL );
POLY1305_VALIDATE_RET( ilen == 0 || input != NULL );
if( ( remaining > 0U ) && ( ctx->queue_len > 0U ) )
{
queue_free_len = ( POLY1305_BLOCK_SIZE_BYTES - ctx->queue_len );
if( ilen < queue_free_len )
{
/* Not enough data to complete the block.
* Store this data with the other leftovers.
*/
memcpy( &ctx->queue[ctx->queue_len],
input,
ilen );
ctx->queue_len += ilen;
remaining = 0U;
}
else
{
/* Enough data to produce a complete block */
memcpy( &ctx->queue[ctx->queue_len],
input,
queue_free_len );
ctx->queue_len = 0U;
poly1305_process( ctx, 1U, ctx->queue, 1U ); /* add padding bit */
offset += queue_free_len;
remaining -= queue_free_len;
}
}
if( remaining >= POLY1305_BLOCK_SIZE_BYTES )
{
nblocks = remaining / POLY1305_BLOCK_SIZE_BYTES;
poly1305_process( ctx, nblocks, &input[offset], 1U );
offset += nblocks * POLY1305_BLOCK_SIZE_BYTES;
remaining %= POLY1305_BLOCK_SIZE_BYTES;
}
if( remaining > 0U )
{
/* Store partial block */
ctx->queue_len = remaining;
memcpy( ctx->queue, &input[offset], remaining );
}
return( 0 );
}
int mbedtls_poly1305_finish( mbedtls_poly1305_context *ctx,
unsigned char mac[16] )
{
POLY1305_VALIDATE_RET( ctx != NULL );
POLY1305_VALIDATE_RET( mac != NULL );
/* Process any leftover data */
if( ctx->queue_len > 0U )
{
/* Add padding bit */
ctx->queue[ctx->queue_len] = 1U;
ctx->queue_len++;
/* Pad with zeroes */
memset( &ctx->queue[ctx->queue_len],
0,
POLY1305_BLOCK_SIZE_BYTES - ctx->queue_len );
poly1305_process( ctx, 1U, /* Process 1 block */
ctx->queue, 0U ); /* Already padded above */
}
poly1305_compute_mac( ctx, mac );
return( 0 );
}
int mbedtls_poly1305_mac( const unsigned char key[32],
const unsigned char *input,
size_t ilen,
unsigned char mac[16] )
{
mbedtls_poly1305_context ctx;
int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
POLY1305_VALIDATE_RET( key != NULL );
POLY1305_VALIDATE_RET( mac != NULL );
POLY1305_VALIDATE_RET( ilen == 0 || input != NULL );
mbedtls_poly1305_init( &ctx );
ret = mbedtls_poly1305_starts( &ctx, key );
if( ret != 0 )
goto cleanup;
ret = mbedtls_poly1305_update( &ctx, input, ilen );
if( ret != 0 )
goto cleanup;
ret = mbedtls_poly1305_finish( &ctx, mac );
cleanup:
mbedtls_poly1305_free( &ctx );
return( ret );
}
#endif /* MBEDTLS_POLY1305_ALT */
#if defined(MBEDTLS_SELF_TEST)
static const unsigned char test_keys[2][32] =
{
{
0x85, 0xd6, 0xbe, 0x78, 0x57, 0x55, 0x6d, 0x33,
0x7f, 0x44, 0x52, 0xfe, 0x42, 0xd5, 0x06, 0xa8,
0x01, 0x03, 0x80, 0x8a, 0xfb, 0x0d, 0xb2, 0xfd,
0x4a, 0xbf, 0xf6, 0xaf, 0x41, 0x49, 0xf5, 0x1b
},
{
0x1c, 0x92, 0x40, 0xa5, 0xeb, 0x55, 0xd3, 0x8a,
0xf3, 0x33, 0x88, 0x86, 0x04, 0xf6, 0xb5, 0xf0,
0x47, 0x39, 0x17, 0xc1, 0x40, 0x2b, 0x80, 0x09,
0x9d, 0xca, 0x5c, 0xbc, 0x20, 0x70, 0x75, 0xc0
}
};
static const unsigned char test_data[2][127] =
{
{
0x43, 0x72, 0x79, 0x70, 0x74, 0x6f, 0x67, 0x72,
0x61, 0x70, 0x68, 0x69, 0x63, 0x20, 0x46, 0x6f,
0x72, 0x75, 0x6d, 0x20, 0x52, 0x65, 0x73, 0x65,
0x61, 0x72, 0x63, 0x68, 0x20, 0x47, 0x72, 0x6f,
0x75, 0x70
},
{
0x27, 0x54, 0x77, 0x61, 0x73, 0x20, 0x62, 0x72,
0x69, 0x6c, 0x6c, 0x69, 0x67, 0x2c, 0x20, 0x61,
0x6e, 0x64, 0x20, 0x74, 0x68, 0x65, 0x20, 0x73,
0x6c, 0x69, 0x74, 0x68, 0x79, 0x20, 0x74, 0x6f,
0x76, 0x65, 0x73, 0x0a, 0x44, 0x69, 0x64, 0x20,
0x67, 0x79, 0x72, 0x65, 0x20, 0x61, 0x6e, 0x64,
0x20, 0x67, 0x69, 0x6d, 0x62, 0x6c, 0x65, 0x20,
0x69, 0x6e, 0x20, 0x74, 0x68, 0x65, 0x20, 0x77,
0x61, 0x62, 0x65, 0x3a, 0x0a, 0x41, 0x6c, 0x6c,
0x20, 0x6d, 0x69, 0x6d, 0x73, 0x79, 0x20, 0x77,
0x65, 0x72, 0x65, 0x20, 0x74, 0x68, 0x65, 0x20,
0x62, 0x6f, 0x72, 0x6f, 0x67, 0x6f, 0x76, 0x65,
0x73, 0x2c, 0x0a, 0x41, 0x6e, 0x64, 0x20, 0x74,
0x68, 0x65, 0x20, 0x6d, 0x6f, 0x6d, 0x65, 0x20,
0x72, 0x61, 0x74, 0x68, 0x73, 0x20, 0x6f, 0x75,
0x74, 0x67, 0x72, 0x61, 0x62, 0x65, 0x2e
}
};
static const size_t test_data_len[2] =
{
34U,
127U
};
static const unsigned char test_mac[2][16] =
{
{
0xa8, 0x06, 0x1d, 0xc1, 0x30, 0x51, 0x36, 0xc6,
0xc2, 0x2b, 0x8b, 0xaf, 0x0c, 0x01, 0x27, 0xa9
},
{
0x45, 0x41, 0x66, 0x9a, 0x7e, 0xaa, 0xee, 0x61,
0xe7, 0x08, 0xdc, 0x7c, 0xbc, 0xc5, 0xeb, 0x62
}
};
#define ASSERT( cond, args ) \
do \
{ \
if( ! ( cond ) ) \
{ \
if( verbose != 0 ) \
mbedtls_printf args; \
\
return( -1 ); \
} \
} \
while( 0 )
int mbedtls_poly1305_self_test( int verbose )
{
unsigned char mac[16];
unsigned i;
int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
for( i = 0U; i < 2U; i++ )
{
if( verbose != 0 )
mbedtls_printf( " Poly1305 test %u ", i );
ret = mbedtls_poly1305_mac( test_keys[i],
test_data[i],
test_data_len[i],
mac );
ASSERT( 0 == ret, ( "error code: %i\n", ret ) );
ASSERT( 0 == memcmp( mac, test_mac[i], 16U ), ( "failed (mac)\n" ) );
if( verbose != 0 )
mbedtls_printf( "passed\n" );
}
if( verbose != 0 )
mbedtls_printf( "\n" );
return( 0 );
}
#endif /* MBEDTLS_SELF_TEST */
#endif /* MBEDTLS_POLY1305_C */
