tests/src/helpers.c

/*
 *  Copyright The Mbed TLS Contributors
 *  SPDX-License-Identifier: Apache-2.0 OR GPL-2.0-or-later
 */

#include <test/constant_flow.h>
#include <test/helpers.h>
#include <test/macros.h>
#include <string.h>

#if defined(MBEDTLS_CHECK_PARAMS)
#include <setjmp.h>
#endif

#if defined(MBEDTLS_PSA_INJECT_ENTROPY)
#include <psa/crypto.h>
#include <test/psa_crypto_helpers.h>
#endif

#if defined(MBEDTLS_TEST_HOOKS) && defined(MBEDTLS_PSA_CRYPTO_C)
#include <test/psa_memory_poisoning_wrappers.h>
#endif

/*----------------------------------------------------------------------------*/
/* Static global variables */

#if defined(MBEDTLS_CHECK_PARAMS)
typedef struct {
    uint8_t expected_call;
    uint8_t expected_call_happened;

    jmp_buf state;

    mbedtls_test_param_failed_location_record_t location_record;
}
param_failed_ctx_t;
static param_failed_ctx_t param_failed_ctx;
#endif

#if defined(MBEDTLS_PLATFORM_C)
static mbedtls_platform_context platform_ctx;
#endif

mbedtls_test_info_t mbedtls_test_info;

/*----------------------------------------------------------------------------*/
/* Helper Functions */

int mbedtls_test_platform_setup(void)
{
    int ret = 0;

#if defined(MBEDTLS_TEST_HOOKS) && defined(MBEDTLS_PSA_CRYPTO_C) \
    && !defined(MBEDTLS_PSA_ASSUME_EXCLUSIVE_BUFFERS) \
    && defined(MBEDTLS_TEST_MEMORY_CAN_POISON)
    mbedtls_poison_test_hooks_setup();
#endif

#if defined(MBEDTLS_PSA_INJECT_ENTROPY)
    /* Make sure that injected entropy is present. Otherwise
     * psa_crypto_init() will fail. This is not necessary for test suites
     * that don't use PSA, but it's harmless (except for leaving a file
     * behind). */
    ret = mbedtls_test_inject_entropy_restore();
    if (ret != 0) {
        return ret;
    }
#endif

#if defined(MBEDTLS_PLATFORM_C)
    ret = mbedtls_platform_setup(&platform_ctx);
#endif /* MBEDTLS_PLATFORM_C */

    return ret;
}

void mbedtls_test_platform_teardown(void)
{
#if defined(MBEDTLS_TEST_HOOKS) && defined(MBEDTLS_PSA_CRYPTO_C) \
    && !defined(MBEDTLS_PSA_ASSUME_EXCLUSIVE_BUFFERS) \
    &&  defined(MBEDTLS_TEST_MEMORY_CAN_POISON)
    mbedtls_poison_test_hooks_teardown();
#endif

#if defined(MBEDTLS_PLATFORM_C)
    mbedtls_platform_teardown(&platform_ctx);
#endif /* MBEDTLS_PLATFORM_C */
}

static int ascii2uc(const char c, unsigned char *uc)
{
    if ((c >= '0') && (c <= '9')) {
        *uc = c - '0';
    } else if ((c >= 'a') && (c <= 'f')) {
        *uc = c - 'a' + 10;
    } else if ((c >= 'A') && (c <= 'F')) {
        *uc = c - 'A' + 10;
    } else {
        return -1;
    }

    return 0;
}

void mbedtls_test_fail(const char *test, int line_no, const char *filename)
{
    if (mbedtls_test_info.result == MBEDTLS_TEST_RESULT_FAILED) {
        /* We've already recorded the test as having failed. Don't
         * overwrite any previous information about the failure. */
        return;
    }
    mbedtls_test_info.result = MBEDTLS_TEST_RESULT_FAILED;
    mbedtls_test_info.test = test;
    mbedtls_test_info.line_no = line_no;
    mbedtls_test_info.filename = filename;
}

void mbedtls_test_skip(const char *test, int line_no, const char *filename)
{
    mbedtls_test_info.result = MBEDTLS_TEST_RESULT_SKIPPED;
    mbedtls_test_info.test = test;
    mbedtls_test_info.line_no = line_no;
    mbedtls_test_info.filename = filename;
}

void mbedtls_test_set_step(unsigned long step)
{
    mbedtls_test_info.step = step;
}

#if defined(MBEDTLS_BIGNUM_C)
unsigned mbedtls_test_case_uses_negative_0 = 0;
#endif

void mbedtls_test_info_reset(void)
{
    mbedtls_test_info.result = MBEDTLS_TEST_RESULT_SUCCESS;
    mbedtls_test_info.step = (unsigned long) (-1);
    mbedtls_test_info.test = 0;
    mbedtls_test_info.line_no = 0;
    mbedtls_test_info.filename = 0;
    memset(mbedtls_test_info.line1, 0, sizeof(mbedtls_test_info.line1));
    memset(mbedtls_test_info.line2, 0, sizeof(mbedtls_test_info.line2));
#if defined(MBEDTLS_BIGNUM_C)
    mbedtls_test_case_uses_negative_0 = 0;
#endif
}

int mbedtls_test_equal(const char *test, int line_no, const char *filename,
                       unsigned long long value1, unsigned long long value2)
{
    TEST_CF_PUBLIC(&value1, sizeof(value1));
    TEST_CF_PUBLIC(&value2, sizeof(value2));

    if (value1 == value2) {
        return 1;
    }

    if (mbedtls_test_info.result == MBEDTLS_TEST_RESULT_FAILED) {
        /* We've already recorded the test as having failed. Don't
         * overwrite any previous information about the failure. */
        return 0;
    }
    mbedtls_test_fail(test, line_no, filename);
    (void) mbedtls_snprintf(mbedtls_test_info.line1,
                            sizeof(mbedtls_test_info.line1),
                            "lhs = 0x%016llx = %lld",
                            value1, (long long) value1);
    (void) mbedtls_snprintf(mbedtls_test_info.line2,
                            sizeof(mbedtls_test_info.line2),
                            "rhs = 0x%016llx = %lld",
                            value2, (long long) value2);
    return 0;
}

int mbedtls_test_le_u(const char *test, int line_no, const char *filename,
                      unsigned long long value1, unsigned long long value2)
{
    TEST_CF_PUBLIC(&value1, sizeof(value1));
    TEST_CF_PUBLIC(&value2, sizeof(value2));

    if (value1 <= value2) {
        return 1;
    }

    if (mbedtls_test_info.result == MBEDTLS_TEST_RESULT_FAILED) {
        /* We've already recorded the test as having failed. Don't
         * overwrite any previous information about the failure. */
        return 0;
    }
    mbedtls_test_fail(test, line_no, filename);
    (void) mbedtls_snprintf(mbedtls_test_info.line1,
                            sizeof(mbedtls_test_info.line1),
                            "lhs = 0x%016llx = %llu",
                            value1, value1);
    (void) mbedtls_snprintf(mbedtls_test_info.line2,
                            sizeof(mbedtls_test_info.line2),
                            "rhs = 0x%016llx = %llu",
                            value2, value2);
    return 0;
}

int mbedtls_test_le_s(const char *test, int line_no, const char *filename,
                      long long value1, long long value2)
{
    TEST_CF_PUBLIC(&value1, sizeof(value1));
    TEST_CF_PUBLIC(&value2, sizeof(value2));

    if (value1 <= value2) {
        return 1;
    }

    if (mbedtls_test_info.result == MBEDTLS_TEST_RESULT_FAILED) {
        /* We've already recorded the test as having failed. Don't
         * overwrite any previous information about the failure. */
        return 0;
    }
    mbedtls_test_fail(test, line_no, filename);
    (void) mbedtls_snprintf(mbedtls_test_info.line1,
                            sizeof(mbedtls_test_info.line1),
                            "lhs = 0x%016llx = %lld",
                            (unsigned long long) value1, value1);
    (void) mbedtls_snprintf(mbedtls_test_info.line2,
                            sizeof(mbedtls_test_info.line2),
                            "rhs = 0x%016llx = %lld",
                            (unsigned long long) value2, value2);
    return 0;
}

int mbedtls_test_unhexify(unsigned char *obuf,
                          size_t obufmax,
                          const char *ibuf,
                          size_t *len)
{
    unsigned char uc, uc2;

    *len = strlen(ibuf);

    /* Must be even number of bytes. */
    if ((*len) & 1) {
        return -1;
    }
    *len /= 2;

    if ((*len) > obufmax) {
        return -1;
    }

    while (*ibuf != 0) {
        if (ascii2uc(*(ibuf++), &uc) != 0) {
            return -1;
        }

        if (ascii2uc(*(ibuf++), &uc2) != 0) {
            return -1;
        }

        *(obuf++) = (uc << 4) | uc2;
    }

    return 0;
}

void mbedtls_test_hexify(unsigned char *obuf,
                         const unsigned char *ibuf,
                         int len)
{
    unsigned char l, h;

    while (len != 0) {
        h = *ibuf / 16;
        l = *ibuf % 16;

        if (h < 10) {
            *obuf++ = '0' + h;
        } else {
            *obuf++ = 'a' + h - 10;
        }

        if (l < 10) {
            *obuf++ = '0' + l;
        } else {
            *obuf++ = 'a' + l - 10;
        }

        ++ibuf;
        len--;
    }
}

unsigned char *mbedtls_test_zero_alloc(size_t len)
{
    void *p;
    size_t actual_len = (len != 0) ? len : 1;

    p = mbedtls_calloc(1, actual_len);
    TEST_HELPER_ASSERT(p != NULL);

    memset(p, 0x00, actual_len);

    return p;
}

unsigned char *mbedtls_test_unhexify_alloc(const char *ibuf, size_t *olen)
{
    unsigned char *obuf;
    size_t len;

    *olen = strlen(ibuf) / 2;

    if (*olen == 0) {
        return mbedtls_test_zero_alloc(*olen);
    }

    obuf = mbedtls_calloc(1, *olen);
    TEST_HELPER_ASSERT(obuf != NULL);
    TEST_HELPER_ASSERT(mbedtls_test_unhexify(obuf, *olen, ibuf, &len) == 0);

    return obuf;
}

int mbedtls_test_hexcmp(uint8_t *a, uint8_t *b,
                        uint32_t a_len, uint32_t b_len)
{
    int ret = 0;
    uint32_t i = 0;

    if (a_len != b_len) {
        return -1;
    }

    for (i = 0; i < a_len; i++) {
        if (a[i] != b[i]) {
            ret = -1;
            break;
        }
    }
    return ret;
}

#if defined(MBEDTLS_CHECK_PARAMS)
void mbedtls_test_param_failed_get_location_record(
    mbedtls_test_param_failed_location_record_t *location_record)
{
    *location_record = param_failed_ctx.location_record;
}

void mbedtls_test_param_failed_expect_call(void)
{
    param_failed_ctx.expected_call_happened = 0;
    param_failed_ctx.expected_call = 1;
}

int mbedtls_test_param_failed_check_expected_call(void)
{
    param_failed_ctx.expected_call = 0;

    if (param_failed_ctx.expected_call_happened != 0) {
        return 0;
    }

    return -1;
}

void *mbedtls_test_param_failed_get_state_buf(void)
{
    return &param_failed_ctx.state;
}

void mbedtls_test_param_failed_reset_state(void)
{
    memset(param_failed_ctx.state, 0, sizeof(param_failed_ctx.state));
}

void mbedtls_param_failed(const char *failure_condition,
                          const char *file,
                          int line)
{
    /* Record the location of the failure */
    param_failed_ctx.location_record.failure_condition = failure_condition;
    param_failed_ctx.location_record.file = file;
    param_failed_ctx.location_record.line = line;

    /* If we are testing the callback function...  */
    if (param_failed_ctx.expected_call != 0) {
        param_failed_ctx.expected_call = 0;
        param_failed_ctx.expected_call_happened = 1;
    } else {
        /* ...else try a long jump. If the execution state has not been set-up
         * or reset then the long jump buffer is all zero's and the call will
         * with high probability fault, emphasizing there is something to look
         * at.
         */

        longjmp(param_failed_ctx.state, 1);
    }
}
#endif /* MBEDTLS_CHECK_PARAMS */

#if defined(MBEDTLS_TEST_HOOKS)
void mbedtls_test_err_add_check(int high, int low,
                                const char *file, int line)
{
    /* Error codes are always negative (a value of zero is a success) however
     * their positive opposites can be easier to understand. The following
     * examples given in comments have been made positive for ease of
     * understanding. The structure of an error code is such:
     *
     *                                                shhhhhhhhlllllll
     *
     * s = sign bit.
     * h = high level error code (includes high level module ID (bits 12..14)
     *     and module-dependent error code (bits 7..11)).
     * l = low level error code.
     */
    if (high > -0x1000 && high != 0) {
        /* high < 0001000000000000
         * No high level module ID bits are set.
         */
        mbedtls_test_fail("'high' is not a high-level error code",
                          line, file);
    } else if (high < -0x7F80) {
        /* high > 0111111110000000
         * Error code is greater than the largest allowed high level module ID.
         */
        mbedtls_test_fail("'high' error code is greater than 15 bits",
                          line, file);
    } else if ((high & 0x7F) != 0) {
        /* high & 0000000001111111
         * Error code contains low level error code bits.
         */
        mbedtls_test_fail("'high' contains a low-level error code",
                          line, file);
    } else if (low < -0x007F) {
        /* low >  0000000001111111
         * Error code contains high or module level error code bits.
         */
        mbedtls_test_fail("'low' error code is greater than 7 bits",
                          line, file);
    } else if (low > 0) {
        mbedtls_test_fail("'low' error code is greater than zero",
                          line, file);
    }
}
#endif /* MBEDTLS_TEST_HOOKS */

#if defined(MBEDTLS_BIGNUM_C)
int mbedtls_test_read_mpi(mbedtls_mpi *X, const char *s)
{
    int negative = 0;
    /* Always set the sign bit to -1 if the input has a minus sign, even for 0.
     * This creates an invalid representation, which mbedtls_mpi_read_string()
     * avoids but we want to be able to create that in test data. */
    if (s[0] == '-') {
        ++s;
        negative = 1;
    }
    /* mbedtls_mpi_read_string() currently retains leading zeros.
     * It always allocates at least one limb for the value 0. */
    if (s[0] == 0) {
        mbedtls_mpi_free(X);
        return 0;
    }
    int ret = mbedtls_mpi_read_string(X, 16, s);
    if (ret != 0) {
        return ret;
    }
    if (negative) {
        if (mbedtls_mpi_cmp_int(X, 0) == 0) {
            ++mbedtls_test_case_uses_negative_0;
        }
        X->s = -1;
    }
    return 0;
}
#endif