mbedtls/tests/suites/test_suite_platform_util.function

/* BEGIN_HEADER */
#include "mbedtls/platform_util.h"
/* END_HEADER */

/* BEGIN_CASE */
void mbedtls_platform_zeroize(int len, int null)
{
    char buf[130];
    char *p = NULL;

    TEST_ASSERT(len <= 128);

    /* Write sentinel values */
    buf[0] = 2;
    buf[len + 1] = 2;

    /* Write non-zero content */
    if (!null) {
        p = &buf[1];
        for (int i = 0; i < len; i++) {
            p[i] = 1;
        }
    }

    /* Check content is non-zero */
    TEST_EQUAL(buf[0], 2);
    for (int i = 0; i < len; i++) {
        TEST_ASSERT(p[i] == 1);
    }
    TEST_EQUAL(buf[len + 1], 2);

    mbedtls_platform_zeroize(p, len);

    /* Check content is zero and sentinels un-changed */
    TEST_EQUAL(buf[0], 2);
    for (int i = 0; i < len; i++) {
        TEST_ASSERT(p[i] == 0);
    }
    TEST_EQUAL(buf[len + 1], 2);
}
/* END_CASE */

/* BEGIN_CASE */
void mbedtls_platform_zeroize_uninitialised(int len, int p)
{
    /*
     * As per #7301: on some platforms, including modern Linux, Clang with Msan
     * does not recognize that explicit_bzero() writes well-defined content to
     * its output buffer. For us, this causes CMAC operations to fail in Msan
     * builds when mbedtls_platform_zeroize() is implemented over
     * explicit_bzero().
     *
     * This test ensures we have a simple/obvious MSan test rather than
     * spurious errors in crypto code that are hard to track down.
     */
    char buf[128];
    mbedtls_platform_zeroize(buf, len);

    TEST_EQUAL(buf[p], 0);
}
/* END_CASE */