On 11/17/20 3:13 AM, KP Singh wrote:
[...]
+
+static int run_set_secureexec(int map_fd, int secureexec)
+{
+
^ same here
+ int child_pid, child_status, ret, null_fd;
+
+ child_pid = fork();
+ if (child_pid == 0) {
+ null_fd = open("/dev/null", O_WRONLY);
+ if (null_fd == -1)
+ exit(errno);
+ dup2(null_fd, STDOUT_FILENO);
+ dup2(null_fd, STDERR_FILENO);
+ close(null_fd);
+
+ /* Ensure that all executions from hereon are
+ * secure by setting a local storage which is read by
+ * the bprm_creds_for_exec hook and sets bprm->secureexec.
+ */
+ ret = update_storage(map_fd, secureexec);
+ if (ret)
+ exit(ret);
+
+ /* If the binary is executed with securexec=1, the dynamic
+ * loader ingores and unsets certain variables like LD_PRELOAD,
+ * TMPDIR etc. TMPDIR is used here to simplify the example, as
+ * LD_PRELOAD requires a real .so file.
+ *
+ * If the value of TMPDIR is set, the bash command returns 10
+ * and if the value is unset, it returns 20.
+ */
+ execle("/bin/bash", "bash", "-c",
+ "[[ -z \"${TMPDIR}\" ]] || exit 10 && exit 20", NULL,
+ bash_envp);
+ exit(errno);
+ } else if (child_pid > 0) {
+ waitpid(child_pid, &child_status, 0);
+ ret = WEXITSTATUS(child_status);
+
+ /* If a secureexec occured, the exit status should be 20.
+ */
+ if (secureexec && ret == 20)
+ return 0;
+
+ /* If normal execution happened the exit code should be 10.
+ */
+ if (!secureexec && ret == 10)
+ return 0;
+
and here (rest looks good to me)
+ }
+
+ return -EINVAL;
+}
+
