sudo-baron-samedit-10.cpp

//sudo_1.8.23-9.el7/plugins/sudoers/sudoers.c
int
sudoers_policy_main(int argc, char * const argv[], int pwflag, char *env_add[],
    void *closure)
{
    ...

    /* Find command in path and apply per-command Defaults. */
[a] cmnd_status = set_cmnd();
    if (cmnd_status == NOT_FOUND_ERROR)
        goto done;

    /* Check for -C overriding def_closefrom. */
    if (user_closefrom >= 0 && user_closefrom != def_closefrom) {
        if (!def_closefrom_override) {
            /* XXX - audit? */
            sudo_warnx(U_("you are not permitted to use the -C option"));
            goto bad;
        }
        def_closefrom = user_closefrom;
    }

[b] [... lots of code here ...]

    /* Require a password if sudoers says so.  */
[c] switch (check_user(validated, sudo_mode)) {
    case true:
        /* user authenticated successfully. */
        break;