selinux: reject setexeccon() on MNT_NOSUID applications with -EACCES (4f189988) · Commits · e / devices / android_kernel_fairphone_FP3

We presently prevent processes from using setexecon() to set the security label of exec()'d processes when NO_NEW_PRIVS is enabled by returning an error; however, we silently ignore setexeccon() when exec()'ing from a nosuid mounted filesystem. This patch makes things a bit more consistent by returning an error in the setexeccon()/nosuid case. Signed-off-by:

Paul Moore <pmoore@redhat.com> Acked-by:

Andy Lutomirski <luto@amacapital.net> Acked-by:

Stephen Smalley <sds@tycho.nsa.gov>

security/selinux/hooks.c

+4 −2

Original line number	Diff line number	Diff line
		@@ -2123,11 +2123,13 @@ static int selinux_bprm_set_creds(struct linux_binprm *bprm)
		new_tsec->exec_sid = 0;

		/*
		* Minimize confusion: if no_new_privs and a transition is
		* explicitly requested, then fail the exec.
		* Minimize confusion: if no_new_privs or nosuid and a
		* transition is explicitly requested, then fail the exec.
		*/
		if (bprm->unsafe & LSM_UNSAFE_NO_NEW_PRIVS)
		return -EPERM;
		if (bprm->file->f_path.mnt->mnt_flags & MNT_NOSUID)
		return -EACCES;
		} else {
		/* Check for a default transition on this program. */
		rc = security_transition_sid(old_tsec->sid, isec->sid,