[RFC v2 PATCH 2/2] kernel: Add SELinux SCTP protocol support

On Thu, Mar 02, 2017 at 03:45:40PM -0500, Stephen Smalley wrote:

On Wed, 2017-02-22 at 17:03 +0000, Richard Haines wrote:

<snip>

quoted

+	return err;
+}
+
+static int selinux_sctp_accept_conn(struct sctp_endpoint *ep,
+				????struct sk_buff *skb)
+{
+	struct sk_security_struct *sksec = ep->base.sk->sk_security;
+	int err;
+	u32 connsid;
+	u32 peersid;
+
+	/* Have COOKIE ECHO so compute the MLS component for the
connection
+	?* and store the information in ep. This will only be used
by
+	?* TCP/peeloff connections as they cause a new socket to be
generated.

Not sure why you say TCP above. ?And won't this be true of accept()'d

Probably just a typo, should be SCTP instead.

sockets too in addition to peeloff ones?

Speaking of accept() path, I think we have an issue there with this
patch, because it's doing:

@@ -7683,8 +7717,6 @@ void sctp_copy_sock(struct sock *newsk, struct

sock *sk,
-       security_sk_clone(sk, newsk);

@@ -7829,6 +7862,11 @@ static void sctp_sock_migrate(struct sock *oldsk,

struct
+       security_sctp_sk_clone(oldep, oldsk, newsk);

But sctp_copy_sock() is called from places other than
sctp_sock_migrate, mainly:
net/sctp/ipv6.c:        sctp_copy_sock(newsk, sk, asoc);
net/sctp/protocol.c:    sctp_copy_sock(newsk, sk, asoc);
Which are on the accept() path.

Ideally it's better to keep the call to security_sctp_sk_clone in
sctp_copy_sock() to get those covered too.

  Marcelo

quoted

+	?* selinux_sctp_sk_clone() will then plug this into the new
socket
+	?* as described in Documentation/security/LSM-sctp.txt
+	?*/
+	err = selinux_skb_peerlbl_sid(skb, ep->base.sk->sk_family,
&peersid);
+	if (err)
+		return err;
+
+	err = selinux_conn_sid(sksec->sid, peersid, &connsid);
+	if (err)
+		return err;
+
+	ep->secid = connsid;
+	ep->peer_secid = peersid;
+
+	return 0;
+}
+

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On Mon, 2017-03-20 at 14:23 -0300, Marcelo Ricardo Leitner wrote:

On Thu, Mar 02, 2017 at 03:45:40PM -0500, Stephen Smalley wrote:

quoted

On Wed, 2017-02-22 at 17:03 +0000, Richard Haines wrote:

<snip>

quoted

quoted

+	return err;
+}
+
+static int selinux_sctp_accept_conn(struct sctp_endpoint *ep,
+				????struct sk_buff *skb)
+{
+	struct sk_security_struct *sksec = ep->base.sk-

quoted

sk_security;

+	int err;
+	u32 connsid;
+	u32 peersid;
+
+	/* Have COOKIE ECHO so compute the MLS component for the
connection
+	?* and store the information in ep. This will only be
used
by
+	?* TCP/peeloff connections as they cause a new socket to
be
generated.

Not sure why you say TCP above. ?And won't this be true of
accept()'d

Probably just a typo, should be SCTP instead.

Yes so changed to "This will only be used by SCTP TCP type sockets
and peeled off connections".

Thanks for pointing this out, I'll fix in next patch set.

? Marcelo

quoted

quoted

+	?* selinux_sctp_sk_clone() will then plug this into the
new
socket
+	?* as described in Documentation/security/LSM-sctp.txt
+	?*/
+	err = selinux_skb_peerlbl_sid(skb, ep->base.sk-

quoted

sk_family,

&peersid);
+	if (err)
+		return err;
+
+	err = selinux_conn_sid(sksec->sid, peersid, &connsid);
+	if (err)
+		return err;
+
+	ep->secid = connsid;
+	ep->peer_secid = peersid;
+
+	return 0;
+}
+

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