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authorVenkat Yekkirala <vyekkirala@trustedcs.com>2006-10-05 15:42:18 -0500
committerDavid S. Miller <davem@sunset.davemloft.net>2006-10-11 23:59:37 -0700
commit5b368e61c2bcb2666bb66e2acf1d6d85ba6f474d (patch)
tree293f595f737540a546ba186ba1f054389aa95f6f /net
parent134b0fc544ba062498451611cb6f3e4454221b3d (diff)
downloadop-kernel-dev-5b368e61c2bcb2666bb66e2acf1d6d85ba6f474d.zip
op-kernel-dev-5b368e61c2bcb2666bb66e2acf1d6d85ba6f474d.tar.gz
IPsec: correct semantics for SELinux policy matching
Currently when an IPSec policy rule doesn't specify a security context, it is assumed to be "unlabeled" by SELinux, and so the IPSec policy rule fails to match to a flow that it would otherwise match to, unless one has explicitly added an SELinux policy rule allowing the flow to "polmatch" to the "unlabeled" IPSec policy rules. In the absence of such an explicitly added SELinux policy rule, the IPSec policy rule fails to match and so the packet(s) flow in clear text without the otherwise applicable xfrm(s) applied. The above SELinux behavior violates the SELinux security notion of "deny by default" which should actually translate to "encrypt by default" in the above case. This was first reported by Evgeniy Polyakov and the way James Morris was seeing the problem was when connecting via IPsec to a confined service on an SELinux box (vsftpd), which did not have the appropriate SELinux policy permissions to send packets via IPsec. With this patch applied, SELinux "polmatching" of flows Vs. IPSec policy rules will only come into play when there's a explicit context specified for the IPSec policy rule (which also means there's corresponding SELinux policy allowing appropriate domains/flows to polmatch to this context). Secondly, when a security module is loaded (in this case, SELinux), the security_xfrm_policy_lookup() hook can return errors other than access denied, such as -EINVAL. We were not handling that correctly, and in fact inverting the return logic and propagating a false "ok" back up to xfrm_lookup(), which then allowed packets to pass as if they were not associated with an xfrm policy. The solution for this is to first ensure that errno values are correctly propagated all the way back up through the various call chains from security_xfrm_policy_lookup(), and handled correctly. Then, flow_cache_lookup() is modified, so that if the policy resolver fails (typically a permission denied via the security module), the flow cache entry is killed rather than having a null policy assigned (which indicates that the packet can pass freely). This also forces any future lookups for the same flow to consult the security module (e.g. SELinux) for current security policy (rather than, say, caching the error on the flow cache entry). This patch: Fix the selinux side of things. This makes sure SELinux polmatching of flow contexts to IPSec policy rules comes into play only when an explicit context is associated with the IPSec policy rule. Also, this no longer defaults the context of a socket policy to the context of the socket since the "no explicit context" case is now handled properly. Signed-off-by: Venkat Yekkirala <vyekkirala@TrustedCS.com> Signed-off-by: James Morris <jmorris@namei.org>
Diffstat (limited to 'net')
-rw-r--r--net/ipv4/xfrm4_policy.c2
-rw-r--r--net/ipv6/xfrm6_policy.c2
-rw-r--r--net/key/af_key.c5
-rw-r--r--net/xfrm/xfrm_policy.c7
-rw-r--r--net/xfrm/xfrm_user.c9
5 files changed, 6 insertions, 19 deletions
diff --git a/net/ipv4/xfrm4_policy.c b/net/ipv4/xfrm4_policy.c
index 7a7a001..1bed0cd 100644
--- a/net/ipv4/xfrm4_policy.c
+++ b/net/ipv4/xfrm4_policy.c
@@ -52,7 +52,7 @@ __xfrm4_find_bundle(struct flowi *fl, struct xfrm_policy *policy)
xdst->u.rt.fl.fl4_dst == fl->fl4_dst &&
xdst->u.rt.fl.fl4_src == fl->fl4_src &&
xdst->u.rt.fl.fl4_tos == fl->fl4_tos &&
- xfrm_bundle_ok(xdst, fl, AF_INET, 0)) {
+ xfrm_bundle_ok(policy, xdst, fl, AF_INET, 0)) {
dst_clone(dst);
break;
}
diff --git a/net/ipv6/xfrm6_policy.c b/net/ipv6/xfrm6_policy.c
index 6a252e2..73cee2e 100644
--- a/net/ipv6/xfrm6_policy.c
+++ b/net/ipv6/xfrm6_policy.c
@@ -73,7 +73,7 @@ __xfrm6_find_bundle(struct flowi *fl, struct xfrm_policy *policy)
xdst->u.rt6.rt6i_src.plen);
if (ipv6_addr_equal(&xdst->u.rt6.rt6i_dst.addr, &fl_dst_prefix) &&
ipv6_addr_equal(&xdst->u.rt6.rt6i_src.addr, &fl_src_prefix) &&
- xfrm_bundle_ok(xdst, fl, AF_INET6,
+ xfrm_bundle_ok(policy, xdst, fl, AF_INET6,
(xdst->u.rt6.rt6i_dst.plen != 128 ||
xdst->u.rt6.rt6i_src.plen != 128))) {
dst_clone(dst);
diff --git a/net/key/af_key.c b/net/key/af_key.c
index ff98e70..20ff7cc 100644
--- a/net/key/af_key.c
+++ b/net/key/af_key.c
@@ -2928,11 +2928,6 @@ static struct xfrm_policy *pfkey_compile_policy(struct sock *sk, int opt,
if (*dir)
goto out;
}
- else {
- *dir = security_xfrm_sock_policy_alloc(xp, sk);
- if (*dir)
- goto out;
- }
*dir = pol->sadb_x_policy_dir-1;
return xp;
diff --git a/net/xfrm/xfrm_policy.c b/net/xfrm/xfrm_policy.c
index fffdd34..695761f 100644
--- a/net/xfrm/xfrm_policy.c
+++ b/net/xfrm/xfrm_policy.c
@@ -1744,7 +1744,7 @@ static struct dst_entry *xfrm_dst_check(struct dst_entry *dst, u32 cookie)
static int stale_bundle(struct dst_entry *dst)
{
- return !xfrm_bundle_ok((struct xfrm_dst *)dst, NULL, AF_UNSPEC, 0);
+ return !xfrm_bundle_ok(NULL, (struct xfrm_dst *)dst, NULL, AF_UNSPEC, 0);
}
void xfrm_dst_ifdown(struct dst_entry *dst, struct net_device *dev)
@@ -1866,7 +1866,8 @@ EXPORT_SYMBOL(xfrm_init_pmtu);
* still valid.
*/
-int xfrm_bundle_ok(struct xfrm_dst *first, struct flowi *fl, int family, int strict)
+int xfrm_bundle_ok(struct xfrm_policy *pol, struct xfrm_dst *first,
+ struct flowi *fl, int family, int strict)
{
struct dst_entry *dst = &first->u.dst;
struct xfrm_dst *last;
@@ -1883,7 +1884,7 @@ int xfrm_bundle_ok(struct xfrm_dst *first, struct flowi *fl, int family, int str
if (fl && !xfrm_selector_match(&dst->xfrm->sel, fl, family))
return 0;
- if (fl && !security_xfrm_flow_state_match(fl, dst->xfrm))
+ if (fl && !security_xfrm_flow_state_match(fl, dst->xfrm, pol))
return 0;
if (dst->xfrm->km.state != XFRM_STATE_VALID)
return 0;
diff --git a/net/xfrm/xfrm_user.c b/net/xfrm/xfrm_user.c
index d54b3a7..2b2e59d 100644
--- a/net/xfrm/xfrm_user.c
+++ b/net/xfrm/xfrm_user.c
@@ -1992,15 +1992,6 @@ static struct xfrm_policy *xfrm_compile_policy(struct sock *sk, int opt,
xp->type = XFRM_POLICY_TYPE_MAIN;
copy_templates(xp, ut, nr);
- if (!xp->security) {
- int err = security_xfrm_sock_policy_alloc(xp, sk);
- if (err) {
- kfree(xp);
- *dir = err;
- return NULL;
- }
- }
-
*dir = p->dir;
return xp;
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