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authorVenkat Yekkirala <vyekkirala@trustedcs.com>2006-11-08 17:04:26 -0600
committerDavid S. Miller <davem@sunset.davemloft.net>2006-12-02 21:21:34 -0800
commit67f83cbf081a70426ff667e8d14f94e13ed3bdca (patch)
tree776a40733eacb9071478f865e6791daa3f6fd602 /security
parent6b877699c6f1efede4545bcecc367786a472eedb (diff)
downloadleg-kernel-67f83cbf081a70426ff667e8d14f94e13ed3bdca.tar.gz
SELinux: Fix SA selection semantics
Fix the selection of an SA for an outgoing packet to be at the same context as the originating socket/flow. This eliminates the SELinux policy's ability to use/sendto SAs with contexts other than the socket's. With this patch applied, the SELinux policy will require one or more of the following for a socket to be able to communicate with/without SAs: 1. To enable a socket to communicate without using labeled-IPSec SAs: allow socket_t unlabeled_t:association { sendto recvfrom } 2. To enable a socket to communicate with labeled-IPSec SAs: allow socket_t self:association { sendto }; allow socket_t peer_sa_t:association { recvfrom }; Signed-off-by: Venkat Yekkirala <vyekkirala@TrustedCS.com> Signed-off-by: James Morris <jmorris@namei.org>
Diffstat (limited to 'security')
-rw-r--r--security/dummy.c7
-rw-r--r--security/selinux/hooks.c26
-rw-r--r--security/selinux/include/xfrm.h7
-rw-r--r--security/selinux/xfrm.c101
4 files changed, 68 insertions, 73 deletions
diff --git a/security/dummy.c b/security/dummy.c
index 0148d1518dd1..558795b237d6 100644
--- a/security/dummy.c
+++ b/security/dummy.c
@@ -886,12 +886,6 @@ static int dummy_xfrm_state_pol_flow_match(struct xfrm_state *x,
return 1;
}
-static int dummy_xfrm_flow_state_match(struct flowi *fl, struct xfrm_state *xfrm,
- struct xfrm_policy *xp)
-{
- return 1;
-}
-
static int dummy_xfrm_decode_session(struct sk_buff *skb, u32 *fl, int ckall)
{
return 0;
@@ -1126,7 +1120,6 @@ void security_fixup_ops (struct security_operations *ops)
set_to_dummy_if_null(ops, xfrm_state_delete_security);
set_to_dummy_if_null(ops, xfrm_policy_lookup);
set_to_dummy_if_null(ops, xfrm_state_pol_flow_match);
- set_to_dummy_if_null(ops, xfrm_flow_state_match);
set_to_dummy_if_null(ops, xfrm_decode_session);
#endif /* CONFIG_SECURITY_NETWORK_XFRM */
#ifdef CONFIG_KEYS
diff --git a/security/selinux/hooks.c b/security/selinux/hooks.c
index 5bbd599a4471..956137baf3e7 100644
--- a/security/selinux/hooks.c
+++ b/security/selinux/hooks.c
@@ -2889,7 +2889,8 @@ static void selinux_task_to_inode(struct task_struct *p,
}
/* Returns error only if unable to parse addresses */
-static int selinux_parse_skb_ipv4(struct sk_buff *skb, struct avc_audit_data *ad)
+static int selinux_parse_skb_ipv4(struct sk_buff *skb,
+ struct avc_audit_data *ad, u8 *proto)
{
int offset, ihlen, ret = -EINVAL;
struct iphdr _iph, *ih;
@@ -2907,6 +2908,9 @@ static int selinux_parse_skb_ipv4(struct sk_buff *skb, struct avc_audit_data *ad
ad->u.net.v4info.daddr = ih->daddr;
ret = 0;
+ if (proto)
+ *proto = ih->protocol;
+
switch (ih->protocol) {
case IPPROTO_TCP: {
struct tcphdr _tcph, *th;
@@ -2950,7 +2954,8 @@ out:
#if defined(CONFIG_IPV6) || defined(CONFIG_IPV6_MODULE)
/* Returns error only if unable to parse addresses */
-static int selinux_parse_skb_ipv6(struct sk_buff *skb, struct avc_audit_data *ad)
+static int selinux_parse_skb_ipv6(struct sk_buff *skb,
+ struct avc_audit_data *ad, u8 *proto)
{
u8 nexthdr;
int ret = -EINVAL, offset;
@@ -2971,6 +2976,9 @@ static int selinux_parse_skb_ipv6(struct sk_buff *skb, struct avc_audit_data *ad
if (offset < 0)
goto out;
+ if (proto)
+ *proto = nexthdr;
+
switch (nexthdr) {
case IPPROTO_TCP: {
struct tcphdr _tcph, *th;
@@ -3007,13 +3015,13 @@ out:
#endif /* IPV6 */
static int selinux_parse_skb(struct sk_buff *skb, struct avc_audit_data *ad,
- char **addrp, int *len, int src)
+ char **addrp, int *len, int src, u8 *proto)
{
int ret = 0;
switch (ad->u.net.family) {
case PF_INET:
- ret = selinux_parse_skb_ipv4(skb, ad);
+ ret = selinux_parse_skb_ipv4(skb, ad, proto);
if (ret || !addrp)
break;
*len = 4;
@@ -3023,7 +3031,7 @@ static int selinux_parse_skb(struct sk_buff *skb, struct avc_audit_data *ad,
#if defined(CONFIG_IPV6) || defined(CONFIG_IPV6_MODULE)
case PF_INET6:
- ret = selinux_parse_skb_ipv6(skb, ad);
+ ret = selinux_parse_skb_ipv6(skb, ad, proto);
if (ret || !addrp)
break;
*len = 16;
@@ -3494,7 +3502,7 @@ static int selinux_socket_sock_rcv_skb(struct sock *sk, struct sk_buff *skb)
ad.u.net.netif = skb->dev ? skb->dev->name : "[unknown]";
ad.u.net.family = family;
- err = selinux_parse_skb(skb, &ad, &addrp, &len, 1);
+ err = selinux_parse_skb(skb, &ad, &addrp, &len, 1, NULL);
if (err)
goto out;
@@ -3820,6 +3828,7 @@ static unsigned int selinux_ip_postroute_last(unsigned int hooknum,
struct avc_audit_data ad;
struct net_device *dev = (struct net_device *)out;
struct sk_security_struct *sksec;
+ u8 proto;
sk = skb->sk;
if (!sk)
@@ -3831,7 +3840,7 @@ static unsigned int selinux_ip_postroute_last(unsigned int hooknum,
ad.u.net.netif = dev->name;
ad.u.net.family = family;
- err = selinux_parse_skb(skb, &ad, &addrp, &len, 0);
+ err = selinux_parse_skb(skb, &ad, &addrp, &len, 0, &proto);
if (err)
goto out;
@@ -3845,7 +3854,7 @@ static unsigned int selinux_ip_postroute_last(unsigned int hooknum,
if (err)
goto out;
- err = selinux_xfrm_postroute_last(sksec->sid, skb, &ad);
+ err = selinux_xfrm_postroute_last(sksec->sid, skb, &ad, proto);
out:
return err ? NF_DROP : NF_ACCEPT;
}
@@ -4764,7 +4773,6 @@ static struct security_operations selinux_ops = {
.xfrm_state_delete_security = selinux_xfrm_state_delete,
.xfrm_policy_lookup = selinux_xfrm_policy_lookup,
.xfrm_state_pol_flow_match = selinux_xfrm_state_pol_flow_match,
- .xfrm_flow_state_match = selinux_xfrm_flow_state_match,
.xfrm_decode_session = selinux_xfrm_decode_session,
#endif
diff --git a/security/selinux/include/xfrm.h b/security/selinux/include/xfrm.h
index 27502365d706..ebd7246a4be5 100644
--- a/security/selinux/include/xfrm.h
+++ b/security/selinux/include/xfrm.h
@@ -19,9 +19,6 @@ int selinux_xfrm_state_delete(struct xfrm_state *x);
int selinux_xfrm_policy_lookup(struct xfrm_policy *xp, u32 fl_secid, u8 dir);
int selinux_xfrm_state_pol_flow_match(struct xfrm_state *x,
struct xfrm_policy *xp, struct flowi *fl);
-int selinux_xfrm_flow_state_match(struct flowi *fl, struct xfrm_state *xfrm,
- struct xfrm_policy *xp);
-
/*
* Extract the security blob from the sock (it's actually on the socket)
@@ -38,7 +35,7 @@ static inline struct inode_security_struct *get_sock_isec(struct sock *sk)
int selinux_xfrm_sock_rcv_skb(u32 sid, struct sk_buff *skb,
struct avc_audit_data *ad);
int selinux_xfrm_postroute_last(u32 isec_sid, struct sk_buff *skb,
- struct avc_audit_data *ad);
+ struct avc_audit_data *ad, u8 proto);
u32 selinux_socket_getpeer_dgram(struct sk_buff *skb);
int selinux_xfrm_decode_session(struct sk_buff *skb, u32 *sid, int ckall);
#else
@@ -49,7 +46,7 @@ static inline int selinux_xfrm_sock_rcv_skb(u32 isec_sid, struct sk_buff *skb,
}
static inline int selinux_xfrm_postroute_last(u32 isec_sid, struct sk_buff *skb,
- struct avc_audit_data *ad)
+ struct avc_audit_data *ad, u8 proto)
{
return 0;
}
diff --git a/security/selinux/xfrm.c b/security/selinux/xfrm.c
index 8fef74271f22..9b777140068f 100644
--- a/security/selinux/xfrm.c
+++ b/security/selinux/xfrm.c
@@ -115,71 +115,40 @@ int selinux_xfrm_state_pol_flow_match(struct xfrm_state *x, struct xfrm_policy *
struct flowi *fl)
{
u32 state_sid;
- u32 pol_sid;
- int err;
+ int rc;
- if (xp->security) {
- if (!x->security)
- /* unlabeled SA and labeled policy can't match */
- return 0;
- else
- state_sid = x->security->ctx_sid;
- pol_sid = xp->security->ctx_sid;
- } else
+ if (!xp->security)
if (x->security)
/* unlabeled policy and labeled SA can't match */
return 0;
else
/* unlabeled policy and unlabeled SA match all flows */
return 1;
-
- err = avc_has_perm(state_sid, pol_sid, SECCLASS_ASSOCIATION,
- ASSOCIATION__POLMATCH,
- NULL);
-
- if (err)
- return 0;
-
- err = avc_has_perm(fl->secid, state_sid, SECCLASS_ASSOCIATION,
- ASSOCIATION__SENDTO,
- NULL)? 0:1;
-
- return err;
-}
-
-/*
- * LSM hook implementation that authorizes that a particular outgoing flow
- * can use a given security association.
- */
-
-int selinux_xfrm_flow_state_match(struct flowi *fl, struct xfrm_state *xfrm,
- struct xfrm_policy *xp)
-{
- int rc = 0;
- u32 sel_sid = SECINITSID_UNLABELED;
- struct xfrm_sec_ctx *ctx;
-
- if (!xp->security)
- if (!xfrm->security)
- return 1;
- else
- return 0;
else
- if (!xfrm->security)
+ if (!x->security)
+ /* unlabeled SA and labeled policy can't match */
return 0;
+ else
+ if (!selinux_authorizable_xfrm(x))
+ /* Not a SELinux-labeled SA */
+ return 0;
- /* Context sid is either set to label or ANY_ASSOC */
- if ((ctx = xfrm->security)) {
- if (!selinux_authorizable_ctx(ctx))
- return 0;
+ state_sid = x->security->ctx_sid;
- sel_sid = ctx->ctx_sid;
- }
+ if (fl->secid != state_sid)
+ return 0;
- rc = avc_has_perm(fl->secid, sel_sid, SECCLASS_ASSOCIATION,
+ rc = avc_has_perm(fl->secid, state_sid, SECCLASS_ASSOCIATION,
ASSOCIATION__SENDTO,
NULL)? 0:1;
+ /*
+ * We don't need a separate SA Vs. policy polmatch check
+ * since the SA is now of the same label as the flow and
+ * a flow Vs. policy polmatch check had already happened
+ * in selinux_xfrm_policy_lookup() above.
+ */
+
return rc;
}
@@ -481,6 +450,13 @@ int selinux_xfrm_sock_rcv_skb(u32 isec_sid, struct sk_buff *skb,
}
}
+ /*
+ * This check even when there's no association involved is
+ * intended, according to Trent Jaeger, to make sure a
+ * process can't engage in non-ipsec communication unless
+ * explicitly allowed by policy.
+ */
+
rc = avc_has_perm(isec_sid, sel_sid, SECCLASS_ASSOCIATION,
ASSOCIATION__RECVFROM, ad);
@@ -492,10 +468,10 @@ int selinux_xfrm_sock_rcv_skb(u32 isec_sid, struct sk_buff *skb,
* If we have no security association, then we need to determine
* whether the socket is allowed to send to an unlabelled destination.
* If we do have a authorizable security association, then it has already been
- * checked in xfrm_policy_lookup hook.
+ * checked in the selinux_xfrm_state_pol_flow_match hook above.
*/
int selinux_xfrm_postroute_last(u32 isec_sid, struct sk_buff *skb,
- struct avc_audit_data *ad)
+ struct avc_audit_data *ad, u8 proto)
{
struct dst_entry *dst;
int rc = 0;
@@ -514,6 +490,27 @@ int selinux_xfrm_postroute_last(u32 isec_sid, struct sk_buff *skb,
}
}
+ switch (proto) {
+ case IPPROTO_AH:
+ case IPPROTO_ESP:
+ case IPPROTO_COMP:
+ /*
+ * We should have already seen this packet once before
+ * it underwent xfrm(s). No need to subject it to the
+ * unlabeled check.
+ */
+ goto out;
+ default:
+ break;
+ }
+
+ /*
+ * This check even when there's no association involved is
+ * intended, according to Trent Jaeger, to make sure a
+ * process can't engage in non-ipsec communication unless
+ * explicitly allowed by policy.
+ */
+
rc = avc_has_perm(isec_sid, SECINITSID_UNLABELED, SECCLASS_ASSOCIATION,
ASSOCIATION__SENDTO, ad);
out: