[PATCH 3.8 002/166] selinux: look for IPsec labels on both inbound and outbound packets

Kamal Mostafa
2014-01-15T21:50:16Z

From: Paul Moore <pmoore@redhat.com>

commit 817eff718dca4e54d5721211ddde0914428fbb7c upstream.

Previously selinux_skb_peerlbl_sid() would only check for labeled
IPsec security labels on inbound packets, this patch enables it to
check both inbound and outbound traffic for labeled IPsec security
labels.

Reported-by: Janak Desai <Janak.Desai@gtri.gatech.edu>
[ Paul: backported to 3.4 kernel ]
Signed-off-by: Paul Moore <pmoore@redhat.com>
Signed-off-by: Luis Henriques <luis.henriques@canonical.com>
Signed-off-by: Kamal Mostafa <kamal@canonical.com>
---
security/selinux/hooks.c | 2 +-
security/selinux/include/xfrm.h | 9 +++----
security/selinux/xfrm.c | 53 ++++++++++++++++++++++++++++++++---------
3 files changed, 48 insertions(+), 16 deletions(-)

diff --git a/security/selinux/hooks.c b/security/selinux/hooks.c
index a3d77ec..1fd031b 100644
--- a/security/selinux/hooks.c
+++ b/security/selinux/hooks.c
@@ -3699,7 +3699,7 @@ static int selinux_skb_peerlbl_sid(struct sk_buff *skb, u16 family, u32 *sid)
u32 nlbl_sid;
u32 nlbl_type;

- selinux_skb_xfrm_sid(skb, &xfrm_sid);
+ selinux_xfrm_skb_sid(skb, &xfrm_sid);
selinux_netlbl_skbuff_getsid(skb, family, &nlbl_type, &nlbl_sid);

err = security_net_peersid_resolve(nlbl_sid, nlbl_type, xfrm_sid, sid);
diff --git a/security/selinux/include/xfrm.h b/security/selinux/include/xfrm.h
index 65f67cb..3ffdadc 100644
--- a/security/selinux/include/xfrm.h
+++ b/security/selinux/include/xfrm.h
@@ -47,6 +47,7 @@ int selinux_xfrm_sock_rcv_skb(u32 sid, struct sk_buff *skb,
int selinux_xfrm_postroute_last(u32 isec_sid, struct sk_buff *skb,
struct common_audit_data *ad, u8 proto);
int selinux_xfrm_decode_session(struct sk_buff *skb, u32 *sid, int ckall);
+int selinux_xfrm_skb_sid(struct sk_buff *skb, u32 *sid);

static inline void selinux_xfrm_notify_policyload(void)
{
@@ -80,12 +81,12 @@ static inline int selinux_xfrm_decode_session(struct sk_buff *skb, u32 *sid, int
static inline void selinux_xfrm_notify_policyload(void)
{
}
-#endif

-static inline void selinux_skb_xfrm_sid(struct sk_buff *skb, u32 *sid)
+static inline int selinux_xfrm_skb_sid(struct sk_buff *skb, u32 *sid)
{
- int err = selinux_xfrm_decode_session(skb, sid, 0);
- BUG_ON(err);
+ *sid = SECSID_NULL;
+ return 0;
}
+#endif

#endif /* _SELINUX_XFRM_H_ */
diff --git a/security/selinux/xfrm.c b/security/selinux/xfrm.c
index 8ab2951..1552b91 100644
--- a/security/selinux/xfrm.c
+++ b/security/selinux/xfrm.c
@@ -152,21 +152,13 @@ int selinux_xfrm_state_pol_flow_match(struct xfrm_state *x, struct xfrm_policy *
return rc;
}

-/*
- * LSM hook implementation that checks and/or returns the xfrm sid for the
- * incoming packet.
- */
-
-int selinux_xfrm_decode_session(struct sk_buff *skb, u32 *sid, int ckall)
+static int selinux_xfrm_skb_sid_ingress(struct sk_buff *skb,
+ u32 *sid, int ckall)
{
- struct sec_path *sp;
+ struct sec_path *sp = skb->sp;

*sid = SECSID_NULL;

- if (skb == NULL)
- return 0;
-
- sp = skb->sp;
if (sp) {
int i, sid_set = 0;

@@ -190,6 +182,45 @@ int selinux_xfrm_decode_session(struct sk_buff *skb, u32 *sid, int ckall)
return 0;
}

+static u32 selinux_xfrm_skb_sid_egress(struct sk_buff *skb)
+{
+ struct dst_entry *dst = skb_dst(skb);
+ struct xfrm_state *x;
+
+ if (dst == NULL)
+ return SECSID_NULL;
+ x = dst->xfrm;
+ if (x == NULL || !selinux_authorizable_xfrm(x))
+ return SECSID_NULL;
+
+ return x->security->ctx_sid;
+}
+
+/*
+ * LSM hook implementation that checks and/or returns the xfrm sid for the
+ * incoming packet.
+ */
+
+int selinux_xfrm_decode_session(struct sk_buff *skb, u32 *sid, int ckall)
+{
+ if (skb == NULL) {
+ *sid = SECSID_NULL;
+ return 0;
+ }
+ return selinux_xfrm_skb_sid_ingress(skb, sid, ckall);
+}
+
+int selinux_xfrm_skb_sid(struct sk_buff *skb, u32 *sid)
+{
+ int rc;
+
+ rc = selinux_xfrm_skb_sid_ingress(skb, sid, 0);
+ if (rc == 0 && *sid == SECSID_NULL)
+ *sid = selinux_xfrm_skb_sid_egress(skb);
+
+ return rc;
+}
+
/*
* Security blob allocation for xfrm_policy and xfrm_state
* CTX does not have a meaningful value on input
--
1.8.3.2