505 lines
15 KiB
C
505 lines
15 KiB
C
/**
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* \file poly1305.c
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*
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* \brief Poly1305 authentication algorithm.
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*
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* Copyright The Mbed TLS Contributors
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* SPDX-License-Identifier: Apache-2.0
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*
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* Licensed under the Apache License, Version 2.0 (the "License"); you may
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* not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
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* WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*/
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#include "common.h"
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#if defined(MBEDTLS_POLY1305_C)
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#include "mbedtls/poly1305.h"
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#include "mbedtls/platform_util.h"
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#include "mbedtls/error.h"
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#include <string.h>
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#include "mbedtls/platform.h"
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#if !defined(MBEDTLS_POLY1305_ALT)
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#define POLY1305_BLOCK_SIZE_BYTES (16U)
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/*
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* Our implementation is tuned for 32-bit platforms with a 64-bit multiplier.
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* However we provided an alternative for platforms without such a multiplier.
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*/
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#if defined(MBEDTLS_NO_64BIT_MULTIPLICATION)
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static uint64_t mul64(uint32_t a, uint32_t b)
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{
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/* a = al + 2**16 ah, b = bl + 2**16 bh */
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const uint16_t al = (uint16_t) a;
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const uint16_t bl = (uint16_t) b;
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const uint16_t ah = a >> 16;
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const uint16_t bh = b >> 16;
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/* ab = al*bl + 2**16 (ah*bl + bl*bh) + 2**32 ah*bh */
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const uint32_t lo = (uint32_t) al * bl;
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const uint64_t me = (uint64_t) ((uint32_t) ah * bl) + (uint32_t) al * bh;
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const uint32_t hi = (uint32_t) ah * bh;
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return lo + (me << 16) + ((uint64_t) hi << 32);
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}
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#else
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static inline uint64_t mul64(uint32_t a, uint32_t b)
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{
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return (uint64_t) a * b;
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}
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#endif
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/**
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* \brief Process blocks with Poly1305.
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*
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* \param ctx The Poly1305 context.
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* \param nblocks Number of blocks to process. Note that this
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* function only processes full blocks.
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* \param input Buffer containing the input block(s).
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* \param needs_padding Set to 0 if the padding bit has already been
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* applied to the input data before calling this
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* function. Otherwise, set this parameter to 1.
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*/
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static void poly1305_process(mbedtls_poly1305_context *ctx,
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size_t nblocks,
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const unsigned char *input,
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uint32_t needs_padding)
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{
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uint64_t d0, d1, d2, d3;
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uint32_t acc0, acc1, acc2, acc3, acc4;
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uint32_t r0, r1, r2, r3;
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uint32_t rs1, rs2, rs3;
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size_t offset = 0U;
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size_t i;
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r0 = ctx->r[0];
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r1 = ctx->r[1];
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r2 = ctx->r[2];
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r3 = ctx->r[3];
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rs1 = r1 + (r1 >> 2U);
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rs2 = r2 + (r2 >> 2U);
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rs3 = r3 + (r3 >> 2U);
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acc0 = ctx->acc[0];
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acc1 = ctx->acc[1];
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acc2 = ctx->acc[2];
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acc3 = ctx->acc[3];
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acc4 = ctx->acc[4];
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/* Process full blocks */
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for (i = 0U; i < nblocks; i++) {
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/* The input block is treated as a 128-bit little-endian integer */
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d0 = MBEDTLS_GET_UINT32_LE(input, offset + 0);
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d1 = MBEDTLS_GET_UINT32_LE(input, offset + 4);
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d2 = MBEDTLS_GET_UINT32_LE(input, offset + 8);
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d3 = MBEDTLS_GET_UINT32_LE(input, offset + 12);
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/* Compute: acc += (padded) block as a 130-bit integer */
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d0 += (uint64_t) acc0;
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d1 += (uint64_t) acc1 + (d0 >> 32U);
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d2 += (uint64_t) acc2 + (d1 >> 32U);
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d3 += (uint64_t) acc3 + (d2 >> 32U);
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acc0 = (uint32_t) d0;
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acc1 = (uint32_t) d1;
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acc2 = (uint32_t) d2;
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acc3 = (uint32_t) d3;
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acc4 += (uint32_t) (d3 >> 32U) + needs_padding;
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/* Compute: acc *= r */
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d0 = mul64(acc0, r0) +
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mul64(acc1, rs3) +
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mul64(acc2, rs2) +
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mul64(acc3, rs1);
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d1 = mul64(acc0, r1) +
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mul64(acc1, r0) +
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mul64(acc2, rs3) +
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mul64(acc3, rs2) +
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mul64(acc4, rs1);
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d2 = mul64(acc0, r2) +
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mul64(acc1, r1) +
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mul64(acc2, r0) +
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mul64(acc3, rs3) +
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mul64(acc4, rs2);
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d3 = mul64(acc0, r3) +
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mul64(acc1, r2) +
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mul64(acc2, r1) +
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mul64(acc3, r0) +
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mul64(acc4, rs3);
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acc4 *= r0;
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/* Compute: acc %= (2^130 - 5) (partial remainder) */
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d1 += (d0 >> 32);
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d2 += (d1 >> 32);
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d3 += (d2 >> 32);
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acc0 = (uint32_t) d0;
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acc1 = (uint32_t) d1;
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acc2 = (uint32_t) d2;
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acc3 = (uint32_t) d3;
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acc4 = (uint32_t) (d3 >> 32) + acc4;
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d0 = (uint64_t) acc0 + (acc4 >> 2) + (acc4 & 0xFFFFFFFCU);
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acc4 &= 3U;
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acc0 = (uint32_t) d0;
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d0 = (uint64_t) acc1 + (d0 >> 32U);
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acc1 = (uint32_t) d0;
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d0 = (uint64_t) acc2 + (d0 >> 32U);
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acc2 = (uint32_t) d0;
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d0 = (uint64_t) acc3 + (d0 >> 32U);
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acc3 = (uint32_t) d0;
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d0 = (uint64_t) acc4 + (d0 >> 32U);
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acc4 = (uint32_t) d0;
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offset += POLY1305_BLOCK_SIZE_BYTES;
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}
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ctx->acc[0] = acc0;
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ctx->acc[1] = acc1;
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ctx->acc[2] = acc2;
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ctx->acc[3] = acc3;
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ctx->acc[4] = acc4;
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}
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/**
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* \brief Compute the Poly1305 MAC
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*
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* \param ctx The Poly1305 context.
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* \param mac The buffer to where the MAC is written. Must be
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* big enough to contain the 16-byte MAC.
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*/
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static void poly1305_compute_mac(const mbedtls_poly1305_context *ctx,
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unsigned char mac[16])
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{
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uint64_t d;
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uint32_t g0, g1, g2, g3, g4;
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uint32_t acc0, acc1, acc2, acc3, acc4;
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uint32_t mask;
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uint32_t mask_inv;
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acc0 = ctx->acc[0];
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acc1 = ctx->acc[1];
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acc2 = ctx->acc[2];
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acc3 = ctx->acc[3];
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acc4 = ctx->acc[4];
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/* Before adding 's' we ensure that the accumulator is mod 2^130 - 5.
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* We do this by calculating acc - (2^130 - 5), then checking if
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* the 131st bit is set. If it is, then reduce: acc -= (2^130 - 5)
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*/
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/* Calculate acc + -(2^130 - 5) */
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d = ((uint64_t) acc0 + 5U);
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g0 = (uint32_t) d;
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d = ((uint64_t) acc1 + (d >> 32));
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g1 = (uint32_t) d;
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d = ((uint64_t) acc2 + (d >> 32));
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g2 = (uint32_t) d;
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d = ((uint64_t) acc3 + (d >> 32));
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g3 = (uint32_t) d;
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g4 = acc4 + (uint32_t) (d >> 32U);
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/* mask == 0xFFFFFFFF if 131st bit is set, otherwise mask == 0 */
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mask = (uint32_t) 0U - (g4 >> 2U);
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mask_inv = ~mask;
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/* If 131st bit is set then acc=g, otherwise, acc is unmodified */
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acc0 = (acc0 & mask_inv) | (g0 & mask);
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acc1 = (acc1 & mask_inv) | (g1 & mask);
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acc2 = (acc2 & mask_inv) | (g2 & mask);
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acc3 = (acc3 & mask_inv) | (g3 & mask);
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/* Add 's' */
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d = (uint64_t) acc0 + ctx->s[0];
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acc0 = (uint32_t) d;
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d = (uint64_t) acc1 + ctx->s[1] + (d >> 32U);
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acc1 = (uint32_t) d;
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d = (uint64_t) acc2 + ctx->s[2] + (d >> 32U);
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acc2 = (uint32_t) d;
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acc3 += ctx->s[3] + (uint32_t) (d >> 32U);
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/* Compute MAC (128 least significant bits of the accumulator) */
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MBEDTLS_PUT_UINT32_LE(acc0, mac, 0);
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MBEDTLS_PUT_UINT32_LE(acc1, mac, 4);
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MBEDTLS_PUT_UINT32_LE(acc2, mac, 8);
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MBEDTLS_PUT_UINT32_LE(acc3, mac, 12);
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}
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void mbedtls_poly1305_init(mbedtls_poly1305_context *ctx)
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{
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mbedtls_platform_zeroize(ctx, sizeof(mbedtls_poly1305_context));
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}
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void mbedtls_poly1305_free(mbedtls_poly1305_context *ctx)
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{
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if (ctx == NULL) {
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return;
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}
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mbedtls_platform_zeroize(ctx, sizeof(mbedtls_poly1305_context));
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}
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int mbedtls_poly1305_starts(mbedtls_poly1305_context *ctx,
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const unsigned char key[32])
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{
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/* r &= 0x0ffffffc0ffffffc0ffffffc0fffffff */
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ctx->r[0] = MBEDTLS_GET_UINT32_LE(key, 0) & 0x0FFFFFFFU;
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ctx->r[1] = MBEDTLS_GET_UINT32_LE(key, 4) & 0x0FFFFFFCU;
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ctx->r[2] = MBEDTLS_GET_UINT32_LE(key, 8) & 0x0FFFFFFCU;
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ctx->r[3] = MBEDTLS_GET_UINT32_LE(key, 12) & 0x0FFFFFFCU;
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ctx->s[0] = MBEDTLS_GET_UINT32_LE(key, 16);
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ctx->s[1] = MBEDTLS_GET_UINT32_LE(key, 20);
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ctx->s[2] = MBEDTLS_GET_UINT32_LE(key, 24);
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ctx->s[3] = MBEDTLS_GET_UINT32_LE(key, 28);
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/* Initial accumulator state */
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ctx->acc[0] = 0U;
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ctx->acc[1] = 0U;
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ctx->acc[2] = 0U;
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ctx->acc[3] = 0U;
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ctx->acc[4] = 0U;
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/* Queue initially empty */
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mbedtls_platform_zeroize(ctx->queue, sizeof(ctx->queue));
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ctx->queue_len = 0U;
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return 0;
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}
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int mbedtls_poly1305_update(mbedtls_poly1305_context *ctx,
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const unsigned char *input,
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size_t ilen)
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{
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size_t offset = 0U;
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size_t remaining = ilen;
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size_t queue_free_len;
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size_t nblocks;
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if ((remaining > 0U) && (ctx->queue_len > 0U)) {
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queue_free_len = (POLY1305_BLOCK_SIZE_BYTES - ctx->queue_len);
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if (ilen < queue_free_len) {
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/* Not enough data to complete the block.
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* Store this data with the other leftovers.
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*/
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memcpy(&ctx->queue[ctx->queue_len],
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input,
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ilen);
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ctx->queue_len += ilen;
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remaining = 0U;
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} else {
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/* Enough data to produce a complete block */
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memcpy(&ctx->queue[ctx->queue_len],
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input,
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queue_free_len);
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ctx->queue_len = 0U;
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poly1305_process(ctx, 1U, ctx->queue, 1U); /* add padding bit */
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offset += queue_free_len;
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remaining -= queue_free_len;
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}
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}
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if (remaining >= POLY1305_BLOCK_SIZE_BYTES) {
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nblocks = remaining / POLY1305_BLOCK_SIZE_BYTES;
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poly1305_process(ctx, nblocks, &input[offset], 1U);
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offset += nblocks * POLY1305_BLOCK_SIZE_BYTES;
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remaining %= POLY1305_BLOCK_SIZE_BYTES;
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}
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if (remaining > 0U) {
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/* Store partial block */
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ctx->queue_len = remaining;
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memcpy(ctx->queue, &input[offset], remaining);
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}
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return 0;
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}
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int mbedtls_poly1305_finish(mbedtls_poly1305_context *ctx,
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unsigned char mac[16])
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{
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/* Process any leftover data */
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if (ctx->queue_len > 0U) {
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/* Add padding bit */
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ctx->queue[ctx->queue_len] = 1U;
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ctx->queue_len++;
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/* Pad with zeroes */
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memset(&ctx->queue[ctx->queue_len],
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0,
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POLY1305_BLOCK_SIZE_BYTES - ctx->queue_len);
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poly1305_process(ctx, 1U, /* Process 1 block */
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ctx->queue, 0U); /* Already padded above */
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}
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poly1305_compute_mac(ctx, mac);
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return 0;
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}
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int mbedtls_poly1305_mac(const unsigned char key[32],
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const unsigned char *input,
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size_t ilen,
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unsigned char mac[16])
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{
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mbedtls_poly1305_context ctx;
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int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
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mbedtls_poly1305_init(&ctx);
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ret = mbedtls_poly1305_starts(&ctx, key);
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if (ret != 0) {
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goto cleanup;
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}
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ret = mbedtls_poly1305_update(&ctx, input, ilen);
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if (ret != 0) {
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goto cleanup;
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}
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ret = mbedtls_poly1305_finish(&ctx, mac);
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cleanup:
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mbedtls_poly1305_free(&ctx);
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return ret;
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}
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#endif /* MBEDTLS_POLY1305_ALT */
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#if defined(MBEDTLS_SELF_TEST)
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static const unsigned char test_keys[2][32] =
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{
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{
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0x85, 0xd6, 0xbe, 0x78, 0x57, 0x55, 0x6d, 0x33,
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0x7f, 0x44, 0x52, 0xfe, 0x42, 0xd5, 0x06, 0xa8,
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0x01, 0x03, 0x80, 0x8a, 0xfb, 0x0d, 0xb2, 0xfd,
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0x4a, 0xbf, 0xf6, 0xaf, 0x41, 0x49, 0xf5, 0x1b
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},
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{
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0x1c, 0x92, 0x40, 0xa5, 0xeb, 0x55, 0xd3, 0x8a,
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0xf3, 0x33, 0x88, 0x86, 0x04, 0xf6, 0xb5, 0xf0,
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0x47, 0x39, 0x17, 0xc1, 0x40, 0x2b, 0x80, 0x09,
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0x9d, 0xca, 0x5c, 0xbc, 0x20, 0x70, 0x75, 0xc0
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}
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};
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static const unsigned char test_data[2][127] =
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{
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{
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0x43, 0x72, 0x79, 0x70, 0x74, 0x6f, 0x67, 0x72,
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0x61, 0x70, 0x68, 0x69, 0x63, 0x20, 0x46, 0x6f,
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0x72, 0x75, 0x6d, 0x20, 0x52, 0x65, 0x73, 0x65,
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0x61, 0x72, 0x63, 0x68, 0x20, 0x47, 0x72, 0x6f,
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0x75, 0x70
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},
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{
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0x27, 0x54, 0x77, 0x61, 0x73, 0x20, 0x62, 0x72,
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0x69, 0x6c, 0x6c, 0x69, 0x67, 0x2c, 0x20, 0x61,
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0x6e, 0x64, 0x20, 0x74, 0x68, 0x65, 0x20, 0x73,
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0x6c, 0x69, 0x74, 0x68, 0x79, 0x20, 0x74, 0x6f,
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0x76, 0x65, 0x73, 0x0a, 0x44, 0x69, 0x64, 0x20,
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0x67, 0x79, 0x72, 0x65, 0x20, 0x61, 0x6e, 0x64,
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0x20, 0x67, 0x69, 0x6d, 0x62, 0x6c, 0x65, 0x20,
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0x69, 0x6e, 0x20, 0x74, 0x68, 0x65, 0x20, 0x77,
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0x61, 0x62, 0x65, 0x3a, 0x0a, 0x41, 0x6c, 0x6c,
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0x20, 0x6d, 0x69, 0x6d, 0x73, 0x79, 0x20, 0x77,
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0x65, 0x72, 0x65, 0x20, 0x74, 0x68, 0x65, 0x20,
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0x62, 0x6f, 0x72, 0x6f, 0x67, 0x6f, 0x76, 0x65,
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0x73, 0x2c, 0x0a, 0x41, 0x6e, 0x64, 0x20, 0x74,
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0x68, 0x65, 0x20, 0x6d, 0x6f, 0x6d, 0x65, 0x20,
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0x72, 0x61, 0x74, 0x68, 0x73, 0x20, 0x6f, 0x75,
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0x74, 0x67, 0x72, 0x61, 0x62, 0x65, 0x2e
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}
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};
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static const size_t test_data_len[2] =
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{
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34U,
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127U
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};
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static const unsigned char test_mac[2][16] =
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{
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{
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0xa8, 0x06, 0x1d, 0xc1, 0x30, 0x51, 0x36, 0xc6,
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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 */
|