mbedtls/library/poly1305.c
Joe Subbiani ad1115a3fd Use byte reading macros in places not using a byte mask
byte shifting opertations throughout library/ were only replaced with
the byte reading macros when an 0xff mask was being used.
The byte reading macros are now more widley used, however they have not
been used in all cases of a byte shift operation, as it detracted from
the immediate readability or otherwise did not seem appropriate.

Signed-off-by: Joe Subbiani <joe.subbiani@arm.com>
2021-08-03 14:08:33 +01:00

551 lines
16 KiB
C

/**
* \file poly1305.c
*
* \brief Poly1305 authentication algorithm.
*
* Copyright The Mbed TLS Contributors
* 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 "common.h"
#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 )
/*
* 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 = MBEDTLS_BYTE_2( a );
const uint16_t bh = MBEDTLS_BYTE_2( b );
/* 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 = MBEDTLS_GET_UINT32_LE( input, offset + 0 );
d1 = MBEDTLS_GET_UINT32_LE( input, offset + 4 );
d2 = MBEDTLS_GET_UINT32_LE( input, offset + 8 );
d3 = MBEDTLS_GET_UINT32_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] = MBEDTLS_BYTE_0( acc0 );
mac[ 1] = MBEDTLS_BYTE_1( acc0 );
mac[ 2] = MBEDTLS_BYTE_2( acc0 );
mac[ 3] = MBEDTLS_BYTE_3( acc0 );
mac[ 4] = MBEDTLS_BYTE_0( acc1 );
mac[ 5] = MBEDTLS_BYTE_1( acc1 );
mac[ 6] = MBEDTLS_BYTE_2( acc1 );
mac[ 7] = MBEDTLS_BYTE_3( acc1 );
mac[ 8] = MBEDTLS_BYTE_0( acc2 );
mac[ 9] = MBEDTLS_BYTE_1( acc2 );
mac[10] = MBEDTLS_BYTE_2( acc2 );
mac[11] = MBEDTLS_BYTE_3( acc2 );
mac[12] = MBEDTLS_BYTE_0( acc3 );
mac[13] = MBEDTLS_BYTE_1( acc3 );
mac[14] = MBEDTLS_BYTE_2( acc3 );
mac[15] = MBEDTLS_BYTE_3( acc3 );
}
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] = MBEDTLS_GET_UINT32_LE( key, 0 ) & 0x0FFFFFFFU;
ctx->r[1] = MBEDTLS_GET_UINT32_LE( key, 4 ) & 0x0FFFFFFCU;
ctx->r[2] = MBEDTLS_GET_UINT32_LE( key, 8 ) & 0x0FFFFFFCU;
ctx->r[3] = MBEDTLS_GET_UINT32_LE( key, 12 ) & 0x0FFFFFFCU;
ctx->s[0] = MBEDTLS_GET_UINT32_LE( key, 16 );
ctx->s[1] = MBEDTLS_GET_UINT32_LE( key, 20 );
ctx->s[2] = MBEDTLS_GET_UINT32_LE( key, 24 );
ctx->s[3] = MBEDTLS_GET_UINT32_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
}
};
/* Make sure no other definition is already present. */
#undef ASSERT
#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 */