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/**

 * \file poly1305.c

 *

 * \brief Poly1305 authentication algorithm.

 *

 *  Copyright (C) 2006-2016, ARM Limited, All Rights Reserved

 *  SPDX-License-Identifier: GPL-2.0

 *

 *  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.

 *

 *  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 

#if defined(MBEDTLS_SELF_TEST)

#if defined(MBEDTLS_PLATFORM_C)

#include "mbedtls/platform.h"

#else

#include 

#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 */