2007-02-09 22:24:47 +08:00
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/*
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2005-04-17 06:20:36 +08:00
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* xfrm4_policy.c
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*
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* Changes:
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* Kazunori MIYAZAWA @USAGI
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* YOSHIFUJI Hideaki @USAGI
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* Split up af-specific portion
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2007-02-09 22:24:47 +08:00
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*
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2005-04-17 06:20:36 +08:00
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*/
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2007-11-14 13:37:28 +08:00
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#include <linux/err.h>
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#include <linux/kernel.h>
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2005-05-04 07:27:10 +08:00
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#include <linux/inetdevice.h>
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2007-11-14 13:35:32 +08:00
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#include <net/dst.h>
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2005-04-17 06:20:36 +08:00
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#include <net/xfrm.h>
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#include <net/ip.h>
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static struct dst_ops xfrm4_dst_ops;
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static struct xfrm_policy_afinfo xfrm4_policy_afinfo;
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2007-11-14 13:37:28 +08:00
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static struct dst_entry *xfrm4_dst_lookup(int tos, xfrm_address_t *saddr,
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xfrm_address_t *daddr)
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2005-04-17 06:20:36 +08:00
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{
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2007-11-14 13:37:28 +08:00
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struct flowi fl = {
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2006-09-20 03:57:34 +08:00
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.nl_u = {
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.ip4_u = {
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2007-11-14 13:37:28 +08:00
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.tos = tos,
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2006-09-20 03:57:34 +08:00
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.daddr = daddr->a4,
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},
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},
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};
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2007-11-14 13:37:28 +08:00
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struct dst_entry *dst;
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struct rtable *rt;
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int err;
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2006-09-20 03:57:34 +08:00
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2007-11-14 13:37:28 +08:00
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if (saddr)
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fl.fl4_src = saddr->a4;
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2008-01-23 14:06:48 +08:00
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err = __ip_route_output_key(&init_net, &rt, &fl);
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2007-11-14 13:37:28 +08:00
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dst = &rt->u.dst;
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if (err)
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dst = ERR_PTR(err);
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return dst;
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}
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static int xfrm4_get_saddr(xfrm_address_t *saddr, xfrm_address_t *daddr)
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{
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struct dst_entry *dst;
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struct rtable *rt;
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dst = xfrm4_dst_lookup(0, NULL, daddr);
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if (IS_ERR(dst))
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return -EHOSTUNREACH;
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rt = (struct rtable *)dst;
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saddr->a4 = rt->rt_src;
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dst_release(dst);
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return 0;
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2006-09-20 03:57:34 +08:00
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}
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2005-04-17 06:20:36 +08:00
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static struct dst_entry *
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__xfrm4_find_bundle(struct flowi *fl, struct xfrm_policy *policy)
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{
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struct dst_entry *dst;
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read_lock_bh(&policy->lock);
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for (dst = policy->bundles; dst; dst = dst->next) {
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2008-11-03 16:24:34 +08:00
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struct xfrm_dst *xdst = (struct xfrm_dst *)dst;
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2005-04-17 06:20:36 +08:00
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if (xdst->u.rt.fl.oif == fl->oif && /*XXX*/
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xdst->u.rt.fl.fl4_dst == fl->fl4_dst &&
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2007-02-09 22:24:47 +08:00
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xdst->u.rt.fl.fl4_src == fl->fl4_src &&
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xdst->u.rt.fl.fl4_tos == fl->fl4_tos &&
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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>
2006-10-06 04:42:18 +08:00
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xfrm_bundle_ok(policy, xdst, fl, AF_INET, 0)) {
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2005-04-17 06:20:36 +08:00
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dst_clone(dst);
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break;
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}
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}
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read_unlock_bh(&policy->lock);
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return dst;
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}
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2007-12-12 01:32:34 +08:00
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static int xfrm4_get_tos(struct flowi *fl)
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2005-04-17 06:20:36 +08:00
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{
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2007-12-12 01:32:34 +08:00
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return fl->fl4_tos;
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}
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2005-04-17 06:20:36 +08:00
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2007-12-21 12:41:12 +08:00
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static int xfrm4_init_path(struct xfrm_dst *path, struct dst_entry *dst,
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int nfheader_len)
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{
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return 0;
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}
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2007-12-12 01:32:34 +08:00
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static int xfrm4_fill_dst(struct xfrm_dst *xdst, struct net_device *dev)
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{
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struct rtable *rt = (struct rtable *)xdst->route;
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2005-04-17 06:20:36 +08:00
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2007-12-12 01:32:34 +08:00
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xdst->u.rt.fl = rt->fl;
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2005-04-17 06:20:36 +08:00
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2007-12-12 01:32:34 +08:00
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xdst->u.dst.dev = dev;
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dev_hold(dev);
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2007-02-07 06:27:32 +08:00
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2007-12-12 01:32:34 +08:00
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xdst->u.rt.idev = in_dev_get(dev);
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if (!xdst->u.rt.idev)
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return -ENODEV;
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2005-04-17 06:20:36 +08:00
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2007-12-12 01:32:34 +08:00
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xdst->u.rt.peer = rt->peer;
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if (rt->peer)
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atomic_inc(&rt->peer->refcnt);
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2007-11-14 13:37:28 +08:00
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2007-12-12 01:32:34 +08:00
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/* Sheit... I remember I did this right. Apparently,
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* it was magically lost, so this code needs audit */
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xdst->u.rt.rt_flags = rt->rt_flags & (RTCF_BROADCAST | RTCF_MULTICAST |
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RTCF_LOCAL);
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xdst->u.rt.rt_type = rt->rt_type;
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xdst->u.rt.rt_src = rt->rt_src;
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xdst->u.rt.rt_dst = rt->rt_dst;
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xdst->u.rt.rt_gateway = rt->rt_gateway;
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xdst->u.rt.rt_spec_dst = rt->rt_spec_dst;
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2005-04-17 06:20:36 +08:00
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return 0;
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}
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static void
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2007-12-13 02:44:16 +08:00
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_decode_session4(struct sk_buff *skb, struct flowi *fl, int reverse)
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2005-04-17 06:20:36 +08:00
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{
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2007-04-21 13:47:35 +08:00
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struct iphdr *iph = ip_hdr(skb);
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2007-04-11 11:50:43 +08:00
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u8 *xprth = skb_network_header(skb) + iph->ihl * 4;
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2005-04-17 06:20:36 +08:00
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memset(fl, 0, sizeof(struct flowi));
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if (!(iph->frag_off & htons(IP_MF | IP_OFFSET))) {
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switch (iph->protocol) {
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case IPPROTO_UDP:
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2006-11-28 03:10:57 +08:00
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case IPPROTO_UDPLITE:
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2005-04-17 06:20:36 +08:00
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case IPPROTO_TCP:
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case IPPROTO_SCTP:
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2005-12-20 06:03:46 +08:00
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case IPPROTO_DCCP:
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2005-04-17 06:20:36 +08:00
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if (pskb_may_pull(skb, xprth + 4 - skb->data)) {
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2006-11-08 16:20:21 +08:00
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__be16 *ports = (__be16 *)xprth;
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2005-04-17 06:20:36 +08:00
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2007-12-13 02:44:16 +08:00
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fl->fl_ip_sport = ports[!!reverse];
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fl->fl_ip_dport = ports[!reverse];
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2005-04-17 06:20:36 +08:00
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}
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break;
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case IPPROTO_ICMP:
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if (pskb_may_pull(skb, xprth + 2 - skb->data)) {
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u8 *icmp = xprth;
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fl->fl_icmp_type = icmp[0];
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fl->fl_icmp_code = icmp[1];
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}
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break;
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case IPPROTO_ESP:
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if (pskb_may_pull(skb, xprth + 4 - skb->data)) {
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2006-09-28 09:49:07 +08:00
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__be32 *ehdr = (__be32 *)xprth;
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2005-04-17 06:20:36 +08:00
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fl->fl_ipsec_spi = ehdr[0];
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}
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break;
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case IPPROTO_AH:
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if (pskb_may_pull(skb, xprth + 8 - skb->data)) {
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2006-09-28 09:49:07 +08:00
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__be32 *ah_hdr = (__be32*)xprth;
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2005-04-17 06:20:36 +08:00
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fl->fl_ipsec_spi = ah_hdr[1];
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}
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break;
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case IPPROTO_COMP:
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if (pskb_may_pull(skb, xprth + 4 - skb->data)) {
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2006-09-28 09:49:07 +08:00
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__be16 *ipcomp_hdr = (__be16 *)xprth;
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2005-04-17 06:20:36 +08:00
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2006-05-23 07:53:22 +08:00
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fl->fl_ipsec_spi = htonl(ntohs(ipcomp_hdr[1]));
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2005-04-17 06:20:36 +08:00
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}
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break;
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default:
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fl->fl_ipsec_spi = 0;
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break;
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2007-04-21 08:09:22 +08:00
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}
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2005-04-17 06:20:36 +08:00
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}
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fl->proto = iph->protocol;
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2007-12-13 02:44:16 +08:00
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fl->fl4_dst = reverse ? iph->saddr : iph->daddr;
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fl->fl4_src = reverse ? iph->daddr : iph->saddr;
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2006-02-24 08:19:26 +08:00
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fl->fl4_tos = iph->tos;
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2005-04-17 06:20:36 +08:00
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}
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2008-01-18 19:56:57 +08:00
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static inline int xfrm4_garbage_collect(struct dst_ops *ops)
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2005-04-17 06:20:36 +08:00
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{
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xfrm4_policy_afinfo.garbage_collect();
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return (atomic_read(&xfrm4_dst_ops.entries) > xfrm4_dst_ops.gc_thresh*2);
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}
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static void xfrm4_update_pmtu(struct dst_entry *dst, u32 mtu)
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{
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struct xfrm_dst *xdst = (struct xfrm_dst *)dst;
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struct dst_entry *path = xdst->route;
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path->ops->update_pmtu(path, mtu);
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}
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2005-05-04 07:27:10 +08:00
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static void xfrm4_dst_destroy(struct dst_entry *dst)
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{
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struct xfrm_dst *xdst = (struct xfrm_dst *)dst;
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if (likely(xdst->u.rt.idev))
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in_dev_put(xdst->u.rt.idev);
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2007-10-18 12:34:46 +08:00
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if (likely(xdst->u.rt.peer))
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2006-12-07 15:45:15 +08:00
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inet_putpeer(xdst->u.rt.peer);
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2005-05-04 07:27:10 +08:00
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xfrm_dst_destroy(xdst);
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}
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static void xfrm4_dst_ifdown(struct dst_entry *dst, struct net_device *dev,
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int unregister)
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{
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struct xfrm_dst *xdst;
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if (!unregister)
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return;
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xdst = (struct xfrm_dst *)dst;
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if (xdst->u.rt.idev->dev == dev) {
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2007-12-07 16:38:10 +08:00
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struct in_device *loopback_idev =
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2008-03-25 20:47:49 +08:00
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in_dev_get(dev_net(dev)->loopback_dev);
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2005-05-04 07:27:10 +08:00
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BUG_ON(!loopback_idev);
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do {
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in_dev_put(xdst->u.rt.idev);
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xdst->u.rt.idev = loopback_idev;
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in_dev_hold(loopback_idev);
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xdst = (struct xfrm_dst *)xdst->u.dst.child;
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} while (xdst->u.dst.xfrm);
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__in_dev_put(loopback_idev);
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}
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xfrm_dst_ifdown(dst, dev);
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}
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2005-04-17 06:20:36 +08:00
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static struct dst_ops xfrm4_dst_ops = {
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.family = AF_INET,
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.protocol = __constant_htons(ETH_P_IP),
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.gc = xfrm4_garbage_collect,
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.update_pmtu = xfrm4_update_pmtu,
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2005-05-04 07:27:10 +08:00
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.destroy = xfrm4_dst_destroy,
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.ifdown = xfrm4_dst_ifdown,
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2007-11-14 13:43:11 +08:00
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.local_out = __ip_local_out,
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2005-04-17 06:20:36 +08:00
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.gc_thresh = 1024,
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.entry_size = sizeof(struct xfrm_dst),
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2008-01-31 12:07:45 +08:00
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.entries = ATOMIC_INIT(0),
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2005-04-17 06:20:36 +08:00
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};
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static struct xfrm_policy_afinfo xfrm4_policy_afinfo = {
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.family = AF_INET,
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.dst_ops = &xfrm4_dst_ops,
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.dst_lookup = xfrm4_dst_lookup,
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2006-09-20 03:57:34 +08:00
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.get_saddr = xfrm4_get_saddr,
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2005-04-17 06:20:36 +08:00
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.find_bundle = __xfrm4_find_bundle,
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.decode_session = _decode_session4,
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2007-12-12 01:32:34 +08:00
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.get_tos = xfrm4_get_tos,
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2007-12-21 12:41:12 +08:00
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.init_path = xfrm4_init_path,
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2007-12-12 01:32:34 +08:00
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.fill_dst = xfrm4_fill_dst,
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2005-04-17 06:20:36 +08:00
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};
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static void __init xfrm4_policy_init(void)
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|
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{
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xfrm_policy_register_afinfo(&xfrm4_policy_afinfo);
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}
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static void __exit xfrm4_policy_fini(void)
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{
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xfrm_policy_unregister_afinfo(&xfrm4_policy_afinfo);
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}
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void __init xfrm4_init(void)
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{
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xfrm4_state_init();
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xfrm4_policy_init();
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}
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