library/sha256.c

/*
 *  FIPS-180-2 compliant SHA-256 implementation
 *
 *  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.
 */
/*
 *  The SHA-256 Secure Hash Standard was published by NIST in 2002.
 *
 *  http://csrc.nist.gov/publications/fips/fips180-2/fips180-2.pdf
 */

#include "common.h"

#if defined(MBEDTLS_SHA256_C)

#    include "mbedtls/sha256.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>
#            include <stdlib.h>
#            define mbedtls_printf printf
#            define mbedtls_calloc calloc
#            define mbedtls_free   free
#        endif /* MBEDTLS_PLATFORM_C */
#    endif /* MBEDTLS_SELF_TEST */

#    define SHA256_VALIDATE_RET(cond) \
        MBEDTLS_INTERNAL_VALIDATE_RET(cond, MBEDTLS_ERR_SHA256_BAD_INPUT_DATA)
#    define SHA256_VALIDATE(cond) MBEDTLS_INTERNAL_VALIDATE(cond)

#    if !defined(MBEDTLS_SHA256_ALT)

/*
 * 32-bit integer manipulation macros (big endian)
 */
#        ifndef GET_UINT32_BE
#            define GET_UINT32_BE(n, b, i)                 \
                do {                                       \
                    (n) = ((uint32_t)(b)[(i)] << 24) |     \
                          ((uint32_t)(b)[(i) + 1] << 16) | \
                          ((uint32_t)(b)[(i) + 2] << 8) |  \
                          ((uint32_t)(b)[(i) + 3]);        \
                } while (0)
#        endif

#        ifndef PUT_UINT32_BE
#            define PUT_UINT32_BE(n, b, i)                     \
                do {                                           \
                    (b)[(i)] = (unsigned char)((n) >> 24);     \
                    (b)[(i) + 1] = (unsigned char)((n) >> 16); \
                    (b)[(i) + 2] = (unsigned char)((n) >> 8);  \
                    (b)[(i) + 3] = (unsigned char)((n));       \
                } while (0)
#        endif

void mbedtls_sha256_init(mbedtls_sha256_context *ctx)
{
    SHA256_VALIDATE(ctx != NULL);

    memset(ctx, 0, sizeof(mbedtls_sha256_context));
}

void mbedtls_sha256_free(mbedtls_sha256_context *ctx)
{
    if (ctx == NULL)
        return;

    mbedtls_platform_zeroize(ctx, sizeof(mbedtls_sha256_context));
}

void mbedtls_sha256_clone(mbedtls_sha256_context *dst,
                          const mbedtls_sha256_context *src)
{
    SHA256_VALIDATE(dst != NULL);
    SHA256_VALIDATE(src != NULL);

    *dst = *src;
}

/*
 * SHA-256 context setup
 */
int mbedtls_sha256_starts(mbedtls_sha256_context *ctx, int is224)
{
    SHA256_VALIDATE_RET(ctx != NULL);

#        if defined(MBEDTLS_SHA224_C)
    SHA256_VALIDATE_RET(is224 == 0 || is224 == 1);
#        else
    SHA256_VALIDATE_RET(is224 == 0);
#        endif

    ctx->total[0] = 0;
    ctx->total[1] = 0;

    if (is224 == 0) {
        /* SHA-256 */
        ctx->state[0] = 0x6A09E667;
        ctx->state[1] = 0xBB67AE85;
        ctx->state[2] = 0x3C6EF372;
        ctx->state[3] = 0xA54FF53A;
        ctx->state[4] = 0x510E527F;
        ctx->state[5] = 0x9B05688C;
        ctx->state[6] = 0x1F83D9AB;
        ctx->state[7] = 0x5BE0CD19;
    } else {
#        if defined(MBEDTLS_SHA224_C)
        /* SHA-224 */
        ctx->state[0] = 0xC1059ED8;
        ctx->state[1] = 0x367CD507;
        ctx->state[2] = 0x3070DD17;
        ctx->state[3] = 0xF70E5939;
        ctx->state[4] = 0xFFC00B31;
        ctx->state[5] = 0x68581511;
        ctx->state[6] = 0x64F98FA7;
        ctx->state[7] = 0xBEFA4FA4;
#        endif
    }

    ctx->is224 = is224;

    return 0;
}

#        if !defined(MBEDTLS_SHA256_PROCESS_ALT)
static const uint32_t K[] = {
    0x428A2F98, 0x71374491, 0xB5C0FBCF, 0xE9B5DBA5, 0x3956C25B, 0x59F111F1,
    0x923F82A4, 0xAB1C5ED5, 0xD807AA98, 0x12835B01, 0x243185BE, 0x550C7DC3,
    0x72BE5D74, 0x80DEB1FE, 0x9BDC06A7, 0xC19BF174, 0xE49B69C1, 0xEFBE4786,
    0x0FC19DC6, 0x240CA1CC, 0x2DE92C6F, 0x4A7484AA, 0x5CB0A9DC, 0x76F988DA,
    0x983E5152, 0xA831C66D, 0xB00327C8, 0xBF597FC7, 0xC6E00BF3, 0xD5A79147,
    0x06CA6351, 0x14292967, 0x27B70A85, 0x2E1B2138, 0x4D2C6DFC, 0x53380D13,
    0x650A7354, 0x766A0ABB, 0x81C2C92E, 0x92722C85, 0xA2BFE8A1, 0xA81A664B,
    0xC24B8B70, 0xC76C51A3, 0xD192E819, 0xD6990624, 0xF40E3585, 0x106AA070,
    0x19A4C116, 0x1E376C08, 0x2748774C, 0x34B0BCB5, 0x391C0CB3, 0x4ED8AA4A,
    0x5B9CCA4F, 0x682E6FF3, 0x748F82EE, 0x78A5636F, 0x84C87814, 0x8CC70208,
    0x90BEFFFA, 0xA4506CEB, 0xBEF9A3F7, 0xC67178F2,
};

#            define SHR(x, n)  (((x)&0xFFFFFFFF) >> (n))
#            define ROTR(x, n) (SHR(x, n) | ((x) << (32 - (n))))

#            define S0(x) (ROTR(x, 7) ^ ROTR(x, 18) ^ SHR(x, 3))
#            define S1(x) (ROTR(x, 17) ^ ROTR(x, 19) ^ SHR(x, 10))

#            define S2(x) (ROTR(x, 2) ^ ROTR(x, 13) ^ ROTR(x, 22))
#            define S3(x) (ROTR(x, 6) ^ ROTR(x, 11) ^ ROTR(x, 25))

#            define F0(x, y, z) (((x) & (y)) | ((z) & ((x) | (y))))
#            define F1(x, y, z) ((z) ^ ((x) & ((y) ^ (z))))

#            define R(t)                                            \
                (local.W[t] = S1(local.W[(t)-2]) + local.W[(t)-7] + \
                              S0(local.W[(t)-15]) + local.W[(t)-16])

#            define P(a, b, c, d, e, f, g, h, x, K)                            \
                do {                                                           \
                    local.temp1 = (h) + S3(e) + F1((e), (f), (g)) + (K) + (x); \
                    local.temp2 = S2(a) + F0((a), (b), (c));                   \
                    (d) += local.temp1;                                        \
                    (h) = local.temp1 + local.temp2;                           \
                } while (0)

int mbedtls_internal_sha256_process(mbedtls_sha256_context *ctx,
                                    const unsigned char data[64])
{
    struct {
        uint32_t temp1, temp2, W[64];
        uint32_t A[8];
    } local;

    unsigned int i;

    SHA256_VALIDATE_RET(ctx != NULL);
    SHA256_VALIDATE_RET((const unsigned char *)data != NULL);

    for (i = 0; i < 8; i++)
        local.A[i] = ctx->state[i];

#            if defined(MBEDTLS_SHA256_SMALLER)
    for (i = 0; i < 64; i++) {
        if (i < 16)
            GET_UINT32_BE(local.W[i], data, 4 * i);
        else
            R(i);

        P(local.A[0], local.A[1], local.A[2], local.A[3], local.A[4],
          local.A[5], local.A[6], local.A[7], local.W[i], K[i]);

        local.temp1 = local.A[7];
        local.A[7] = local.A[6];
        local.A[6] = local.A[5];
        local.A[5] = local.A[4];
        local.A[4] = local.A[3];
        local.A[3] = local.A[2];
        local.A[2] = local.A[1];
        local.A[1] = local.A[0];
        local.A[0] = local.temp1;
    }
#            else /* MBEDTLS_SHA256_SMALLER */
    for (i = 0; i < 16; i++)
        GET_UINT32_BE(local.W[i], data, 4 * i);

    for (i = 0; i < 16; i += 8) {
        P(local.A[0], local.A[1], local.A[2], local.A[3], local.A[4],
          local.A[5], local.A[6], local.A[7], local.W[i + 0], K[i + 0]);
        P(local.A[7], local.A[0], local.A[1], local.A[2], local.A[3],
          local.A[4], local.A[5], local.A[6], local.W[i + 1], K[i + 1]);
        P(local.A[6], local.A[7], local.A[0], local.A[1], local.A[2],
          local.A[3], local.A[4], local.A[5], local.W[i + 2], K[i + 2]);
        P(local.A[5], local.A[6], local.A[7], local.A[0], local.A[1],
          local.A[2], local.A[3], local.A[4], local.W[i + 3], K[i + 3]);
        P(local.A[4], local.A[5], local.A[6], local.A[7], local.A[0],
          local.A[1], local.A[2], local.A[3], local.W[i + 4], K[i + 4]);
        P(local.A[3], local.A[4], local.A[5], local.A[6], local.A[7],
          local.A[0], local.A[1], local.A[2], local.W[i + 5], K[i + 5]);
        P(local.A[2], local.A[3], local.A[4], local.A[5], local.A[6],
          local.A[7], local.A[0], local.A[1], local.W[i + 6], K[i + 6]);
        P(local.A[1], local.A[2], local.A[3], local.A[4], local.A[5],
          local.A[6], local.A[7], local.A[0], local.W[i + 7], K[i + 7]);
    }

    for (i = 16; i < 64; i += 8) {
        P(local.A[0], local.A[1], local.A[2], local.A[3], local.A[4],
          local.A[5], local.A[6], local.A[7], R(i + 0), K[i + 0]);
        P(local.A[7], local.A[0], local.A[1], local.A[2], local.A[3],
          local.A[4], local.A[5], local.A[6], R(i + 1), K[i + 1]);
        P(local.A[6], local.A[7], local.A[0], local.A[1], local.A[2],
          local.A[3], local.A[4], local.A[5], R(i + 2), K[i + 2]);
        P(local.A[5], local.A[6], local.A[7], local.A[0], local.A[1],
          local.A[2], local.A[3], local.A[4], R(i + 3), K[i + 3]);
        P(local.A[4], local.A[5], local.A[6], local.A[7], local.A[0],
          local.A[1], local.A[2], local.A[3], R(i + 4), K[i + 4]);
        P(local.A[3], local.A[4], local.A[5], local.A[6], local.A[7],
          local.A[0], local.A[1], local.A[2], R(i + 5), K[i + 5]);
        P(local.A[2], local.A[3], local.A[4], local.A[5], local.A[6],
          local.A[7], local.A[0], local.A[1], R(i + 6), K[i + 6]);
        P(local.A[1], local.A[2], local.A[3], local.A[4], local.A[5],
          local.A[6], local.A[7], local.A[0], R(i + 7), K[i + 7]);
    }
#            endif /* MBEDTLS_SHA256_SMALLER */

    for (i = 0; i < 8; i++)
        ctx->state[i] += local.A[i];

    /* Zeroise buffers and variables to clear sensitive data from memory. */
    mbedtls_platform_zeroize(&local, sizeof(local));

    return 0;
}

#        endif /* !MBEDTLS_SHA256_PROCESS_ALT */

/*
 * SHA-256 process buffer
 */
int mbedtls_sha256_update(mbedtls_sha256_context *ctx,
                          const unsigned char *input,
                          size_t ilen)
{
    int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
    size_t fill;
    uint32_t left;

    SHA256_VALIDATE_RET(ctx != NULL);
    SHA256_VALIDATE_RET(ilen == 0 || input != NULL);

    if (ilen == 0)
        return 0;

    left = ctx->total[0] & 0x3F;
    fill = 64 - left;

    ctx->total[0] += (uint32_t)ilen;
    ctx->total[0] &= 0xFFFFFFFF;

    if (ctx->total[0] < (uint32_t)ilen)
        ctx->total[1]++;

    if (left && ilen >= fill) {
        memcpy((void *)(ctx->buffer + left), input, fill);

        if ((ret = mbedtls_internal_sha256_process(ctx, ctx->buffer)) != 0)
            return ret;

        input += fill;
        ilen -= fill;
        left = 0;
    }

    while (ilen >= 64) {
        if ((ret = mbedtls_internal_sha256_process(ctx, input)) != 0)
            return ret;

        input += 64;
        ilen -= 64;
    }

    if (ilen > 0)
        memcpy((void *)(ctx->buffer + left), input, ilen);

    return 0;
}

/*
 * SHA-256 final digest
 */
int mbedtls_sha256_finish(mbedtls_sha256_context *ctx, unsigned char *output)
{
    int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
    uint32_t used;
    uint32_t high, low;

    SHA256_VALIDATE_RET(ctx != NULL);
    SHA256_VALIDATE_RET((unsigned char *)output != NULL);

    /*
     * Add padding: 0x80 then 0x00 until 8 bytes remain for the length
     */
    used = ctx->total[0] & 0x3F;

    ctx->buffer[used++] = 0x80;

    if (used <= 56) {
        /* Enough room for padding + length in current block */
        memset(ctx->buffer + used, 0, 56 - used);
    } else {
        /* We'll need an extra block */
        memset(ctx->buffer + used, 0, 64 - used);

        if ((ret = mbedtls_internal_sha256_process(ctx, ctx->buffer)) != 0)
            return ret;

        memset(ctx->buffer, 0, 56);
    }

    /*
     * Add message length
     */
    high = (ctx->total[0] >> 29) | (ctx->total[1] << 3);
    low = (ctx->total[0] << 3);

    PUT_UINT32_BE(high, ctx->buffer, 56);
    PUT_UINT32_BE(low, ctx->buffer, 60);

    if ((ret = mbedtls_internal_sha256_process(ctx, ctx->buffer)) != 0)
        return ret;

    /*
     * Output final state
     */
    PUT_UINT32_BE(ctx->state[0], output, 0);
    PUT_UINT32_BE(ctx->state[1], output, 4);
    PUT_UINT32_BE(ctx->state[2], output, 8);
    PUT_UINT32_BE(ctx->state[3], output, 12);
    PUT_UINT32_BE(ctx->state[4], output, 16);
    PUT_UINT32_BE(ctx->state[5], output, 20);
    PUT_UINT32_BE(ctx->state[6], output, 24);

#        if defined(MBEDTLS_SHA224_C)
    if (ctx->is224 == 0)
#        endif
        PUT_UINT32_BE(ctx->state[7], output, 28);

    return 0;
}

#    endif /* !MBEDTLS_SHA256_ALT */

/*
 * output = SHA-256( input buffer )
 */
int mbedtls_sha256(const unsigned char *input,
                   size_t ilen,
                   unsigned char *output,
                   int is224)
{
    int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
    mbedtls_sha256_context ctx;

#    if defined(MBEDTLS_SHA224_C)
    SHA256_VALIDATE_RET(is224 == 0 || is224 == 1);
#    else
    SHA256_VALIDATE_RET(is224 == 0);
#    endif

    SHA256_VALIDATE_RET(ilen == 0 || input != NULL);
    SHA256_VALIDATE_RET((unsigned char *)output != NULL);

    mbedtls_sha256_init(&ctx);

    if ((ret = mbedtls_sha256_starts(&ctx, is224)) != 0)
        goto exit;

    if ((ret = mbedtls_sha256_update(&ctx, input, ilen)) != 0)
        goto exit;

    if ((ret = mbedtls_sha256_finish(&ctx, output)) != 0)
        goto exit;

exit:
    mbedtls_sha256_free(&ctx);

    return ret;
}

#    if defined(MBEDTLS_SELF_TEST)
/*
 * FIPS-180-2 test vectors
 */
static const unsigned char sha256_test_buf[3][57] = {
    { "abc" },
    { "abcdbcdecdefdefgefghfghighijhijkijkljklmklmnlmnomnopnopq" },
    { "" }
};

static const size_t sha256_test_buflen[3] = { 3, 56, 1000 };

static const unsigned char sha256_test_sum[6][32] = {
    /*
     * SHA-224 test vectors
     */
    { 0x23, 0x09, 0x7D, 0x22, 0x34, 0x05, 0xD8, 0x22, 0x86, 0x42,
      0xA4, 0x77, 0xBD, 0xA2, 0x55, 0xB3, 0x2A, 0xAD, 0xBC, 0xE4,
      0xBD, 0xA0, 0xB3, 0xF7, 0xE3, 0x6C, 0x9D, 0xA7 },
    { 0x75, 0x38, 0x8B, 0x16, 0x51, 0x27, 0x76, 0xCC, 0x5D, 0xBA,
      0x5D, 0xA1, 0xFD, 0x89, 0x01, 0x50, 0xB0, 0xC6, 0x45, 0x5C,
      0xB4, 0xF5, 0x8B, 0x19, 0x52, 0x52, 0x25, 0x25 },
    { 0x20, 0x79, 0x46, 0x55, 0x98, 0x0C, 0x91, 0xD8, 0xBB, 0xB4,
      0xC1, 0xEA, 0x97, 0x61, 0x8A, 0x4B, 0xF0, 0x3F, 0x42, 0x58,
      0x19, 0x48, 0xB2, 0xEE, 0x4E, 0xE7, 0xAD, 0x67 },

    /*
     * SHA-256 test vectors
     */
    { 0xBA, 0x78, 0x16, 0xBF, 0x8F, 0x01, 0xCF, 0xEA, 0x41, 0x41, 0x40,
      0xDE, 0x5D, 0xAE, 0x22, 0x23, 0xB0, 0x03, 0x61, 0xA3, 0x96, 0x17,
      0x7A, 0x9C, 0xB4, 0x10, 0xFF, 0x61, 0xF2, 0x00, 0x15, 0xAD },
    { 0x24, 0x8D, 0x6A, 0x61, 0xD2, 0x06, 0x38, 0xB8, 0xE5, 0xC0, 0x26,
      0x93, 0x0C, 0x3E, 0x60, 0x39, 0xA3, 0x3C, 0xE4, 0x59, 0x64, 0xFF,
      0x21, 0x67, 0xF6, 0xEC, 0xED, 0xD4, 0x19, 0xDB, 0x06, 0xC1 },
    { 0xCD, 0xC7, 0x6E, 0x5C, 0x99, 0x14, 0xFB, 0x92, 0x81, 0xA1, 0xC7,
      0xE2, 0x84, 0xD7, 0x3E, 0x67, 0xF1, 0x80, 0x9A, 0x48, 0xA4, 0x97,
      0x20, 0x0E, 0x04, 0x6D, 0x39, 0xCC, 0xC7, 0x11, 0x2C, 0xD0 }
};

/*
 * Checkup routine
 */
int mbedtls_sha256_self_test(int verbose)
{
    int i, j, k, buflen, ret = 0;
    unsigned char *buf;
    unsigned char sha256sum[32];
    mbedtls_sha256_context ctx;

    buf = mbedtls_calloc(1024, sizeof(unsigned char));
    if (NULL == buf) {
        if (verbose != 0)
            mbedtls_printf("Buffer allocation failed\n");

        return 1;
    }

    mbedtls_sha256_init(&ctx);

    for (i = 0; i < 6; i++) {
        j = i % 3;
        k = i < 3;

        if (verbose != 0)
            mbedtls_printf("  SHA-%d test #%d: ", 256 - k * 32, j + 1);

        if ((ret = mbedtls_sha256_starts(&ctx, k)) != 0)
            goto fail;

        if (j == 2) {
            memset(buf, 'a', buflen = 1000);

            for (j = 0; j < 1000; j++) {
                ret = mbedtls_sha256_update(&ctx, buf, buflen);
                if (ret != 0)
                    goto fail;
            }

        } else {
            ret = mbedtls_sha256_update(&ctx, sha256_test_buf[j],
                                        sha256_test_buflen[j]);
            if (ret != 0)
                goto fail;
        }

        if ((ret = mbedtls_sha256_finish(&ctx, sha256sum)) != 0)
            goto fail;

        if (memcmp(sha256sum, sha256_test_sum[i], 32 - k * 4) != 0) {
            ret = 1;
            goto fail;
        }

        if (verbose != 0)
            mbedtls_printf("passed\n");
    }

    if (verbose != 0)
        mbedtls_printf("\n");

    goto exit;

fail:
    if (verbose != 0)
        mbedtls_printf("failed\n");

exit:
    mbedtls_sha256_free(&ctx);
    mbedtls_free(buf);

    return ret;
}

#    endif /* MBEDTLS_SELF_TEST */

#endif /* MBEDTLS_SHA256_C */