Introduce p_canwait() and MAC Framework and MAC Policy entry points

mac_check_proc_wait(), which control the ability to wait4() specific
processes.  This permits MAC policies to limit information flow from
children that have changed label, although has to be handled carefully
due to common programming expectations regarding the behavior of
wait4().  The cr_seeotheruids() check in p_canwait() is #if 0'd for
this reason.

The mac_stub and mac_test policies are updated to reflect these new
entry points.

Sponsored by:	SPAWAR, SPARTA
Obtained from:	TrustedBSD Project

1 files changed, 15 insertions, 0 deletions

diff --git a/sys/security/mac/mac_process.c b/sys/security/mac/mac_process.c
index 8dda7b1..436c55b 100644
--- a/sys/security/mac/mac_process.c
+++ b/sys/security/mac/mac_process.c
@@ -650,3 +650,18 @@ mac_check_proc_setresgid(struct proc *proc, struct ucred *cred, gid_t rgid,
 	MAC_CHECK(check_proc_setresgid, cred, rgid, egid, sgid);
 	return (error);
 }
+
+int
+mac_check_proc_wait(struct ucred *cred, struct proc *proc)
+{
+	int error;
+
+	PROC_LOCK_ASSERT(proc, MA_OWNED);
+
+	if (!mac_enforce_process)
+		return (0);
+
+	MAC_CHECK(check_proc_wait, cred, proc);
+
+	return (error);
+}