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authorLinus Torvalds <torvalds@linux-foundation.org>2013-12-15 11:28:02 -0800
committerLinus Torvalds <torvalds@linux-foundation.org>2013-12-15 11:28:02 -0800
commitb5745c59627854afb3cd3f3860ee6f4571e2b633 (patch)
treedf9f3bb37b4cf0f3c52c970927bed4a843234e29 /security
parent29b1deb2a48a9dd02b93597aa4c055a24c0e989f (diff)
parentd93aca6050b10cd7d8b491637c3b5344c5680cac (diff)
downloadlinux-b5745c59627854afb3cd3f3860ee6f4571e2b633.tar.gz
Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jmorris/linux-security
Pull SELinux fixes from James Morris. * 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jmorris/linux-security: selinux: process labeled IPsec TCP SYN-ACK packets properly in selinux_ip_postroute() selinux: look for IPsec labels on both inbound and outbound packets selinux: handle TCP SYN-ACK packets correctly in selinux_ip_postroute() selinux: handle TCP SYN-ACK packets correctly in selinux_ip_output() selinux: fix possible memory leak
Diffstat (limited to 'security')
-rw-r--r--security/selinux/hooks.c137
-rw-r--r--security/selinux/include/xfrm.h8
-rw-r--r--security/selinux/xfrm.c62
3 files changed, 165 insertions, 42 deletions
diff --git a/security/selinux/hooks.c b/security/selinux/hooks.c
index 98b1caa1c1d..419491d8e7d 100644
--- a/security/selinux/hooks.c
+++ b/security/selinux/hooks.c
@@ -53,6 +53,7 @@
#include <net/ip.h> /* for local_port_range[] */
#include <net/sock.h>
#include <net/tcp.h> /* struct or_callable used in sock_rcv_skb */
+#include <net/inet_connection_sock.h>
#include <net/net_namespace.h>
#include <net/netlabel.h>
#include <linux/uaccess.h>
@@ -3824,7 +3825,7 @@ 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);
@@ -3842,6 +3843,30 @@ static int selinux_skb_peerlbl_sid(struct sk_buff *skb, u16 family, u32 *sid)
return 0;
}
+/**
+ * selinux_conn_sid - Determine the child socket label for a connection
+ * @sk_sid: the parent socket's SID
+ * @skb_sid: the packet's SID
+ * @conn_sid: the resulting connection SID
+ *
+ * If @skb_sid is valid then the user:role:type information from @sk_sid is
+ * combined with the MLS information from @skb_sid in order to create
+ * @conn_sid. If @skb_sid is not valid then then @conn_sid is simply a copy
+ * of @sk_sid. Returns zero on success, negative values on failure.
+ *
+ */
+static int selinux_conn_sid(u32 sk_sid, u32 skb_sid, u32 *conn_sid)
+{
+ int err = 0;
+
+ if (skb_sid != SECSID_NULL)
+ err = security_sid_mls_copy(sk_sid, skb_sid, conn_sid);
+ else
+ *conn_sid = sk_sid;
+
+ return err;
+}
+
/* socket security operations */
static int socket_sockcreate_sid(const struct task_security_struct *tsec,
@@ -4448,7 +4473,7 @@ static int selinux_inet_conn_request(struct sock *sk, struct sk_buff *skb,
struct sk_security_struct *sksec = sk->sk_security;
int err;
u16 family = sk->sk_family;
- u32 newsid;
+ u32 connsid;
u32 peersid;
/* handle mapped IPv4 packets arriving via IPv6 sockets */
@@ -4458,16 +4483,11 @@ static int selinux_inet_conn_request(struct sock *sk, struct sk_buff *skb,
err = selinux_skb_peerlbl_sid(skb, family, &peersid);
if (err)
return err;
- if (peersid == SECSID_NULL) {
- req->secid = sksec->sid;
- req->peer_secid = SECSID_NULL;
- } else {
- err = security_sid_mls_copy(sksec->sid, peersid, &newsid);
- if (err)
- return err;
- req->secid = newsid;
- req->peer_secid = peersid;
- }
+ err = selinux_conn_sid(sksec->sid, peersid, &connsid);
+ if (err)
+ return err;
+ req->secid = connsid;
+ req->peer_secid = peersid;
return selinux_netlbl_inet_conn_request(req, family);
}
@@ -4727,6 +4747,7 @@ static unsigned int selinux_ipv6_forward(const struct nf_hook_ops *ops,
static unsigned int selinux_ip_output(struct sk_buff *skb,
u16 family)
{
+ struct sock *sk;
u32 sid;
if (!netlbl_enabled())
@@ -4735,8 +4756,27 @@ static unsigned int selinux_ip_output(struct sk_buff *skb,
/* we do this in the LOCAL_OUT path and not the POST_ROUTING path
* because we want to make sure we apply the necessary labeling
* before IPsec is applied so we can leverage AH protection */
- if (skb->sk) {
- struct sk_security_struct *sksec = skb->sk->sk_security;
+ sk = skb->sk;
+ if (sk) {
+ struct sk_security_struct *sksec;
+
+ if (sk->sk_state == TCP_LISTEN)
+ /* if the socket is the listening state then this
+ * packet is a SYN-ACK packet which means it needs to
+ * be labeled based on the connection/request_sock and
+ * not the parent socket. unfortunately, we can't
+ * lookup the request_sock yet as it isn't queued on
+ * the parent socket until after the SYN-ACK is sent.
+ * the "solution" is to simply pass the packet as-is
+ * as any IP option based labeling should be copied
+ * from the initial connection request (in the IP
+ * layer). it is far from ideal, but until we get a
+ * security label in the packet itself this is the
+ * best we can do. */
+ return NF_ACCEPT;
+
+ /* standard practice, label using the parent socket */
+ sksec = sk->sk_security;
sid = sksec->sid;
} else
sid = SECINITSID_KERNEL;
@@ -4806,27 +4846,36 @@ 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;
- /* if the packet is being forwarded then get the peer label from the
- * packet itself; otherwise check to see if it is from a local
- * application or the kernel, if from an application get the peer label
- * from the sending socket, otherwise use the kernel's sid */
- 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
+ * to determine which and if the packet is being forwarded
+ * query the packet directly to determine the security label. */
if (skb->skb_iif) {
secmark_perm = PACKET__FORWARD_OUT;
if (selinux_skb_peerlbl_sid(skb, family, &peer_sid))
@@ -4835,7 +4884,45 @@ static unsigned int selinux_ip_postroute(struct sk_buff *skb, int ifindex,
secmark_perm = PACKET__SEND;
peer_sid = SECINITSID_KERNEL;
}
+ } else if (sk->sk_state == TCP_LISTEN) {
+ /* Locally generated packet but the associated socket is in the
+ * listening state which means this is a SYN-ACK packet. In
+ * this particular case the correct security label is assigned
+ * to the connection/request_sock but unfortunately we can't
+ * query the request_sock as it isn't queued on the parent
+ * socket until after the SYN-ACK packet is sent; the only
+ * viable choice is to regenerate the label like we do in
+ * selinux_inet_conn_request(). See also selinux_ip_output()
+ * for similar problems. */
+ u32 skb_sid;
+ 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;
} else {
+ /* Locally generated packet, fetch the security label from the
+ * associated socket. */
struct sk_security_struct *sksec = sk->sk_security;
peer_sid = sksec->sid;
secmark_perm = PACKET__SEND;
diff --git a/security/selinux/include/xfrm.h b/security/selinux/include/xfrm.h
index 0dec76c64cf..48c3cc94c16 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 a91d205ec0c..0462cb3ff0a 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,
@@ -327,19 +358,22 @@ int selinux_xfrm_state_alloc_acquire(struct xfrm_state *x,
return rc;
ctx = kmalloc(sizeof(*ctx) + str_len, GFP_ATOMIC);
- if (!ctx)
- return -ENOMEM;
+ if (!ctx) {
+ rc = -ENOMEM;
+ goto out;
+ }
ctx->ctx_doi = XFRM_SC_DOI_LSM;
ctx->ctx_alg = XFRM_SC_ALG_SELINUX;
ctx->ctx_sid = secid;
ctx->ctx_len = str_len;
memcpy(ctx->ctx_str, ctx_str, str_len);
- kfree(ctx_str);
x->security = ctx;
atomic_inc(&selinux_xfrm_refcount);
- return 0;
+out:
+ kfree(ctx_str);
+ return rc;
}
/*