* [PATCH 1/2] selinux: look for IPsec labels on both inbound and outbound packets
2013-12-10 19:53 [PATCH 0/2] Additional TCP SYN-ACK fixes for labeled IPsec Paul Moore
@ 2013-12-10 19:53 ` Paul Moore
2013-12-10 19:53 ` [PATCH 2/2] selinux: process labeled IPsec TCP SYN-ACK packets properly in selinux_ip_postroute() Paul Moore
1 sibling, 0 replies; 3+ messages in thread
From: Paul Moore @ 2013-12-10 19:53 UTC (permalink / raw)
To: selinux; +Cc: janak.desai
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>
Cc: stable@vger.kernel.org
Signed-off-by: Paul Moore <pmoore@redhat.com>
---
security/selinux/hooks.c | 2 +-
security/selinux/include/xfrm.h | 8 ++++--
security/selinux/xfrm.c | 51 +++++++++++++++++++++++++++++++--------
3 files changed, 47 insertions(+), 14 deletions(-)
diff --git a/security/selinux/hooks.c b/security/selinux/hooks.c
index 17d7689..95cb134 100644
--- a/security/selinux/hooks.c
+++ b/security/selinux/hooks.c
@@ -3829,7 +3829,7 @@ static int selinux_skb_peerlbl_sid(struct sk_buff *skb, u16 family, u32 *sid)
u32 nlbl_sid;
u32 nlbl_type;
- err = selinux_skb_xfrm_sid(skb, &xfrm_sid);
+ err = selinux_xfrm_skb_sid(skb, &xfrm_sid);
if (unlikely(err))
return -EACCES;
err = selinux_netlbl_skbuff_getsid(skb, family, &nlbl_type, &nlbl_sid);
diff --git a/security/selinux/include/xfrm.h b/security/selinux/include/xfrm.h
index 0dec76c..48c3cc9 100644
--- a/security/selinux/include/xfrm.h
+++ b/security/selinux/include/xfrm.h
@@ -39,6 +39,7 @@ int selinux_xfrm_sock_rcv_skb(u32 sk_sid, struct sk_buff *skb,
int selinux_xfrm_postroute_last(u32 sk_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)
{
@@ -79,11 +80,12 @@ static inline int selinux_xfrm_decode_session(struct sk_buff *skb, u32 *sid,
static inline void selinux_xfrm_notify_policyload(void)
{
}
-#endif
-static inline int selinux_skb_xfrm_sid(struct sk_buff *skb, u32 *sid)
+static inline int selinux_xfrm_skb_sid(struct sk_buff *skb, u32 *sid)
{
- return selinux_xfrm_decode_session(skb, sid, 0);
+ *sid = SECSID_NULL;
+ return 0;
}
+#endif
#endif /* _SELINUX_XFRM_H_ */
diff --git a/security/selinux/xfrm.c b/security/selinux/xfrm.c
index cf79a45..0462cb3 100644
--- a/security/selinux/xfrm.c
+++ b/security/selinux/xfrm.c
@@ -209,19 +209,26 @@ int selinux_xfrm_state_pol_flow_match(struct xfrm_state *x,
NULL) ? 0 : 1);
}
-/*
- * 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 u32 selinux_xfrm_skb_sid_egress(struct sk_buff *skb)
{
- u32 sid_session = SECSID_NULL;
- struct sec_path *sp;
+ struct dst_entry *dst = skb_dst(skb);
+ struct xfrm_state *x;
- if (skb == NULL)
- goto out;
+ if (dst == NULL)
+ return SECSID_NULL;
+ x = dst->xfrm;
+ if (x == NULL || !selinux_authorizable_xfrm(x))
+ return SECSID_NULL;
+
+ return x->security->ctx_sid;
+}
+
+static int selinux_xfrm_skb_sid_ingress(struct sk_buff *skb,
+ u32 *sid, int ckall)
+{
+ u32 sid_session = SECSID_NULL;
+ struct sec_path *sp = skb->sp;
- sp = skb->sp;
if (sp) {
int i;
@@ -248,6 +255,30 @@ out:
}
/*
+ * 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;
+}
+
+/*
* LSM hook implementation that allocs and transfers uctx spec to xfrm_policy.
*/
int selinux_xfrm_policy_alloc(struct xfrm_sec_ctx **ctxp,
--
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^ permalink raw reply related [flat|nested] 3+ messages in thread* [PATCH 2/2] selinux: process labeled IPsec TCP SYN-ACK packets properly in selinux_ip_postroute()
2013-12-10 19:53 [PATCH 0/2] Additional TCP SYN-ACK fixes for labeled IPsec Paul Moore
2013-12-10 19:53 ` [PATCH 1/2] selinux: look for IPsec labels on both inbound and outbound packets Paul Moore
@ 2013-12-10 19:53 ` Paul Moore
1 sibling, 0 replies; 3+ messages in thread
From: Paul Moore @ 2013-12-10 19:53 UTC (permalink / raw)
To: selinux; +Cc: janak.desai
Due to difficulty in arriving at the proper security label for
TCP SYN-ACK packets in selinux_ip_postroute(), we need to check packets
while/before they are undergoing XFRM transforms instead of waiting
until afterwards so that we can determine the correct security label.
Reported-by: Janak Desai <Janak.Desai@gtri.gatech.edu>
Cc: stable@vger.kernel.org
Signed-off-by: Paul Moore <pmoore@redhat.com>
---
security/selinux/hooks.c | 42 +++++++++++++++++++++++++++++++++++-------
1 file changed, 35 insertions(+), 7 deletions(-)
diff --git a/security/selinux/hooks.c b/security/selinux/hooks.c
index 95cb134..a98228e 100644
--- a/security/selinux/hooks.c
+++ b/security/selinux/hooks.c
@@ -4846,22 +4846,31 @@ static unsigned int selinux_ip_postroute(struct sk_buff *skb, int ifindex,
* as fast and as clean as possible. */
if (!selinux_policycap_netpeer)
return selinux_ip_postroute_compat(skb, ifindex, family);
+
+ secmark_active = selinux_secmark_enabled();
+ peerlbl_active = selinux_peerlbl_enabled();
+ if (!secmark_active && !peerlbl_active)
+ return NF_ACCEPT;
+
+ sk = skb->sk;
+
#ifdef CONFIG_XFRM
/* If skb->dst->xfrm is non-NULL then the packet is undergoing an IPsec
* packet transformation so allow the packet to pass without any checks
* since we'll have another chance to perform access control checks
* when the packet is on it's final way out.
* NOTE: there appear to be some IPv6 multicast cases where skb->dst
- * is NULL, in this case go ahead and apply access control. */
- if (skb_dst(skb) != NULL && skb_dst(skb)->xfrm != NULL)
+ * is NULL, in this case go ahead and apply access control.
+ * NOTE: if this is a local socket (skb->sk != NULL) that is in the
+ * TCP listening state we cannot wait until the XFRM processing
+ * is done as we will miss out on the SA label if we do;
+ * unfortunately, this means more work, but it is only once per
+ * connection. */
+ if (skb_dst(skb) != NULL && skb_dst(skb)->xfrm != NULL &&
+ !(sk != NULL && sk->sk_state == TCP_LISTEN))
return NF_ACCEPT;
#endif
- secmark_active = selinux_secmark_enabled();
- peerlbl_active = selinux_peerlbl_enabled();
- if (!secmark_active && !peerlbl_active)
- return NF_ACCEPT;
- sk = skb->sk;
if (sk == NULL) {
/* Without an associated socket the packet is either coming
* from the kernel or it is being forwarded; check the packet
@@ -4889,6 +4898,25 @@ static unsigned int selinux_ip_postroute(struct sk_buff *skb, int ifindex,
struct sk_security_struct *sksec = sk->sk_security;
if (selinux_skb_peerlbl_sid(skb, family, &skb_sid))
return NF_DROP;
+ /* At this point, if the returned skb peerlbl is SECSID_NULL
+ * and the packet has been through at least one XFRM
+ * transformation then we must be dealing with the "final"
+ * form of labeled IPsec packet; since we've already applied
+ * all of our access controls on this packet we can safely
+ * pass the packet. */
+ if (skb_sid == SECSID_NULL) {
+ switch (family) {
+ case PF_INET:
+ if (IPCB(skb)->flags & IPSKB_XFRM_TRANSFORMED)
+ return NF_ACCEPT;
+ break;
+ case PF_INET6:
+ if (IP6CB(skb)->flags & IP6SKB_XFRM_TRANSFORMED)
+ return NF_ACCEPT;
+ default:
+ return NF_DROP_ERR(-ECONNREFUSED);
+ }
+ }
if (selinux_conn_sid(sksec->sid, skb_sid, &peer_sid))
return NF_DROP;
secmark_perm = PACKET__SEND;
--
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^ permalink raw reply related [flat|nested] 3+ messages in thread