/** * \file poly1305.c * * \brief Poly1305 authentication algorithm. * * Copyright The Mbed TLS Contributors * SPDX-License-Identifier: Apache-2.0 OR GPL-2.0-or-later * * This file is provided under the Apache License 2.0, or the * GNU General Public License v2.0 or later. * * ********** * Apache License 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. * * ********** * * ********** * GNU General Public License v2.0 or later: * * 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., * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA. * * ********** */ #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 <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; 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; 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 */