mbedtls/tests/suites/test_suite_net.function

/* BEGIN_HEADER */

#include "mbedtls/net_sockets.h"

#if defined(unix) || defined(__unix__) || defined(__unix) || \
    defined(__APPLE__) || defined(__QNXNTO__) || \
    defined(__HAIKU__) || defined(__midipix__)
#define MBEDTLS_PLATFORM_IS_UNIXLIKE
#endif

#if defined(MBEDTLS_PLATFORM_IS_UNIXLIKE)
#include <sys/resource.h>
#include <sys/stat.h>
#include <sys/time.h>
#include <sys/types.h>
#include <fcntl.h>
#include <unistd.h>
#endif


#if defined(MBEDTLS_PLATFORM_IS_UNIXLIKE)
/** Open a file on the given file descriptor.
 *
 * This is disruptive if there is already something open on that descriptor.
 * Caller beware.
 *
 * \param ctx           An initialized, but unopened socket context.
 *                      On success, it refers to the opened file (\p wanted_fd).
 * \param wanted_fd     The desired file descriptor.
 *
 * \return              \c 0 on success, a negative error code on error.
 */
static int open_file_on_fd(mbedtls_net_context *ctx, int wanted_fd)
{
    int got_fd = open("/dev/null", O_RDONLY);
    TEST_ASSERT(got_fd >= 0);
    if (got_fd != wanted_fd) {
        TEST_ASSERT(dup2(got_fd, wanted_fd) >= 0);
        TEST_ASSERT(close(got_fd) >= 0);
    }
    ctx->fd = wanted_fd;
    return 0;
exit:
    return -1;
}
#endif /* MBEDTLS_PLATFORM_IS_UNIXLIKE */

/* END_HEADER */

/* BEGIN_DEPENDENCIES
 * depends_on:MBEDTLS_NET_C
 * END_DEPENDENCIES
 */

/* BEGIN_CASE */
void context_init_free(int reinit)
{
    mbedtls_net_context ctx;

    mbedtls_net_init(&ctx);
    mbedtls_net_free(&ctx);

    if (reinit) {
        mbedtls_net_init(&ctx);
    }
    mbedtls_net_free(&ctx);

    /* This test case always succeeds, functionally speaking. A plausible
     * bug might trigger an invalid pointer dereference or a memory leak. */
    goto exit;
}
/* END_CASE */

/* BEGIN_CASE depends_on:MBEDTLS_PLATFORM_IS_UNIXLIKE */
void poll_beyond_fd_setsize()
{
    /* Test that mbedtls_net_poll does not misbehave when given a file
     * descriptor greater or equal to FD_SETSIZE. This code is specific to
     * platforms with a Unix-like select() function, which is where
     * FD_SETSIZE is a concern. */

    struct rlimit rlim_nofile;
    int restore_rlim_nofile = 0;
    int ret;
    mbedtls_net_context ctx;
    uint8_t buf[1];

    mbedtls_net_init(&ctx);

    /* On many systems, by default, the maximum permitted file descriptor
     * number is less than FD_SETSIZE. If so, raise the limit if
     * possible.
     *
     * If the limit can't be raised, a file descriptor opened by the
     * net_sockets module will be less than FD_SETSIZE, so the test
     * is not necessary and we mark it as skipped.
     * A file descriptor could still be higher than FD_SETSIZE if it was
     * opened before the limit was lowered (which is something an application
     * might do); but we don't do such things in our test code, so the unit
     * test will run if it can.
     */
    TEST_ASSERT(getrlimit(RLIMIT_NOFILE, &rlim_nofile) == 0);
    if (rlim_nofile.rlim_cur < FD_SETSIZE + 1) {
        rlim_t old_rlim_cur = rlim_nofile.rlim_cur;
        rlim_nofile.rlim_cur = FD_SETSIZE + 1;
        TEST_ASSUME(setrlimit(RLIMIT_NOFILE, &rlim_nofile) == 0);
        rlim_nofile.rlim_cur = old_rlim_cur;
        restore_rlim_nofile = 1;
    }

    TEST_ASSERT(open_file_on_fd(&ctx, FD_SETSIZE) == 0);

    /* In principle, mbedtls_net_poll() with valid arguments should succeed.
     * However, we know that on Unix-like platforms (and others), this function
     * is implemented on top of select() and fd_set, which do not support
     * file descriptors greater or equal to FD_SETSIZE. So we expect to hit
     * this platform limitation.
     *
     * If mbedtls_net_poll() does not proprely check that ctx.fd is in range,
     * it may still happen to return the expected failure code, but if this
     * is problematic on the particular platform where the code is running,
     * a memory sanitizer such as UBSan should catch it.
     */
    ret = mbedtls_net_poll(&ctx, MBEDTLS_NET_POLL_READ, 0);
    TEST_EQUAL(ret, MBEDTLS_ERR_NET_POLL_FAILED);

    /* mbedtls_net_recv_timeout() uses select() and fd_set in the same way. */
    ret = mbedtls_net_recv_timeout(&ctx, buf, sizeof(buf), 0);
    TEST_EQUAL(ret, MBEDTLS_ERR_NET_POLL_FAILED);

exit:
    mbedtls_net_free(&ctx);
    if (restore_rlim_nofile) {
        setrlimit(RLIMIT_NOFILE, &rlim_nofile);
    }
}
/* END_CASE */