linux/net/ipv6/xfrm6_policy.c

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/*
* xfrm6_policy.c: based on xfrm4_policy.c
*
* Authors:
* Mitsuru KANDA @USAGI
* Kazunori MIYAZAWA @USAGI
* Kunihiro Ishiguro <kunihiro@ipinfusion.com>
* IPv6 support
* YOSHIFUJI Hideaki
* Split up af-specific portion
*
*/
#include <linux/err.h>
#include <linux/kernel.h>
#include <linux/netdevice.h>
#include <net/addrconf.h>
#include <net/dst.h>
#include <net/xfrm.h>
#include <net/ip.h>
#include <net/ipv6.h>
#include <net/ip6_route.h>
#if defined(CONFIG_IPV6_MIP6) || defined(CONFIG_IPV6_MIP6_MODULE)
#include <net/mip6.h>
#endif
static struct xfrm_policy_afinfo xfrm6_policy_afinfo;
static struct dst_entry *xfrm6_dst_lookup(struct net *net, int tos,
xfrm_address_t *saddr,
xfrm_address_t *daddr)
{
struct flowi fl = {};
struct dst_entry *dst;
int err;
memcpy(&fl.fl6_dst, daddr, sizeof(fl.fl6_dst));
if (saddr)
memcpy(&fl.fl6_src, saddr, sizeof(fl.fl6_src));
dst = ip6_route_output(net, NULL, &fl);
err = dst->error;
if (dst->error) {
dst_release(dst);
dst = ERR_PTR(err);
}
return dst;
}
static int xfrm6_get_saddr(struct net *net,
xfrm_address_t *saddr, xfrm_address_t *daddr)
{
struct dst_entry *dst;
struct net_device *dev;
dst = xfrm6_dst_lookup(net, 0, NULL, daddr);
if (IS_ERR(dst))
return -EHOSTUNREACH;
dev = ip6_dst_idev(dst)->dev;
ipv6_dev_get_saddr(dev_net(dev), dev,
(struct in6_addr *)&daddr->a6, 0,
(struct in6_addr *)&saddr->a6);
dst_release(dst);
return 0;
}
static struct dst_entry *
__xfrm6_find_bundle(struct flowi *fl, struct xfrm_policy *policy)
{
struct dst_entry *dst;
/* Still not clear if we should set fl->fl6_{src,dst}... */
read_lock_bh(&policy->lock);
for (dst = policy->bundles; dst; dst = dst->next) {
struct xfrm_dst *xdst = (struct xfrm_dst*)dst;
struct in6_addr fl_dst_prefix, fl_src_prefix;
ipv6_addr_prefix(&fl_dst_prefix,
&fl->fl6_dst,
xdst->u.rt6.rt6i_dst.plen);
ipv6_addr_prefix(&fl_src_prefix,
&fl->fl6_src,
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) &&
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>
2006-10-05 20:42:18 +00:00
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);
break;
}
}
read_unlock_bh(&policy->lock);
return dst;
}
static int xfrm6_get_tos(struct flowi *fl)
{
return 0;
}
static int xfrm6_init_path(struct xfrm_dst *path, struct dst_entry *dst,
int nfheader_len)
{
if (dst->ops->family == AF_INET6) {
struct rt6_info *rt = (struct rt6_info*)dst;
if (rt->rt6i_node)
path->path_cookie = rt->rt6i_node->fn_sernum;
}
path->u.rt6.rt6i_nfheader_len = nfheader_len;
return 0;
}
static int xfrm6_fill_dst(struct xfrm_dst *xdst, struct net_device *dev,
struct flowi *fl)
{
struct rt6_info *rt = (struct rt6_info*)xdst->route;
xdst->u.dst.dev = dev;
dev_hold(dev);
xdst->u.rt6.rt6i_idev = in6_dev_get(dev);
if (!xdst->u.rt6.rt6i_idev)
return -ENODEV;
/* Sheit... I remember I did this right. Apparently,
* it was magically lost, so this code needs audit */
xdst->u.rt6.rt6i_flags = rt->rt6i_flags & (RTF_ANYCAST |
RTF_LOCAL);
xdst->u.rt6.rt6i_metric = rt->rt6i_metric;
xdst->u.rt6.rt6i_node = rt->rt6i_node;
if (rt->rt6i_node)
xdst->route_cookie = rt->rt6i_node->fn_sernum;
xdst->u.rt6.rt6i_gateway = rt->rt6i_gateway;
xdst->u.rt6.rt6i_dst = rt->rt6i_dst;
xdst->u.rt6.rt6i_src = rt->rt6i_src;
return 0;
}
static inline void
_decode_session6(struct sk_buff *skb, struct flowi *fl, int reverse)
{
int onlyproto = 0;
u16 offset = skb_network_header_len(skb);
struct ipv6hdr *hdr = ipv6_hdr(skb);
struct ipv6_opt_hdr *exthdr;
const unsigned char *nh = skb_network_header(skb);
u8 nexthdr = nh[IP6CB(skb)->nhoff];
memset(fl, 0, sizeof(struct flowi));
ipv6_addr_copy(&fl->fl6_dst, reverse ? &hdr->saddr : &hdr->daddr);
ipv6_addr_copy(&fl->fl6_src, reverse ? &hdr->daddr : &hdr->saddr);
while (nh + offset + 1 < skb->data ||
pskb_may_pull(skb, nh + offset + 1 - skb->data)) {
nh = skb_network_header(skb);
exthdr = (struct ipv6_opt_hdr *)(nh + offset);
switch (nexthdr) {
case NEXTHDR_FRAGMENT:
onlyproto = 1;
case NEXTHDR_ROUTING:
case NEXTHDR_HOP:
case NEXTHDR_DEST:
offset += ipv6_optlen(exthdr);
nexthdr = exthdr->nexthdr;
exthdr = (struct ipv6_opt_hdr *)(nh + offset);
break;
case IPPROTO_UDP:
[NET]: Supporting UDP-Lite (RFC 3828) in Linux This is a revision of the previously submitted patch, which alters the way files are organized and compiled in the following manner: * UDP and UDP-Lite now use separate object files * source file dependencies resolved via header files net/ipv{4,6}/udp_impl.h * order of inclusion files in udp.c/udplite.c adapted accordingly [NET/IPv4]: Support for the UDP-Lite protocol (RFC 3828) This patch adds support for UDP-Lite to the IPv4 stack, provided as an extension to the existing UDPv4 code: * generic routines are all located in net/ipv4/udp.c * UDP-Lite specific routines are in net/ipv4/udplite.c * MIB/statistics support in /proc/net/snmp and /proc/net/udplite * shared API with extensions for partial checksum coverage [NET/IPv6]: Extension for UDP-Lite over IPv6 It extends the existing UDPv6 code base with support for UDP-Lite in the same manner as per UDPv4. In particular, * UDPv6 generic and shared code is in net/ipv6/udp.c * UDP-Litev6 specific extensions are in net/ipv6/udplite.c * MIB/statistics support in /proc/net/snmp6 and /proc/net/udplite6 * support for IPV6_ADDRFORM * aligned the coding style of protocol initialisation with af_inet6.c * made the error handling in udpv6_queue_rcv_skb consistent; to return `-1' on error on all error cases * consolidation of shared code [NET]: UDP-Lite Documentation and basic XFRM/Netfilter support The UDP-Lite patch further provides * API documentation for UDP-Lite * basic xfrm support * basic netfilter support for IPv4 and IPv6 (LOG target) Signed-off-by: Gerrit Renker <gerrit@erg.abdn.ac.uk> Signed-off-by: David S. Miller <davem@davemloft.net>
2006-11-27 19:10:57 +00:00
case IPPROTO_UDPLITE:
case IPPROTO_TCP:
case IPPROTO_SCTP:
case IPPROTO_DCCP:
if (!onlyproto && (nh + offset + 4 < skb->data ||
pskb_may_pull(skb, nh + offset + 4 - skb->data))) {
__be16 *ports = (__be16 *)exthdr;
fl->fl_ip_sport = ports[!!reverse];
fl->fl_ip_dport = ports[!reverse];
}
fl->proto = nexthdr;
return;
case IPPROTO_ICMPV6:
if (!onlyproto && pskb_may_pull(skb, nh + offset + 2 - skb->data)) {
u8 *icmp = (u8 *)exthdr;
fl->fl_icmp_type = icmp[0];
fl->fl_icmp_code = icmp[1];
}
fl->proto = nexthdr;
return;
#if defined(CONFIG_IPV6_MIP6) || defined(CONFIG_IPV6_MIP6_MODULE)
case IPPROTO_MH:
if (!onlyproto && pskb_may_pull(skb, nh + offset + 3 - skb->data)) {
struct ip6_mh *mh;
mh = (struct ip6_mh *)exthdr;
fl->fl_mh_type = mh->ip6mh_type;
}
fl->proto = nexthdr;
return;
#endif
/* XXX Why are there these headers? */
case IPPROTO_AH:
case IPPROTO_ESP:
case IPPROTO_COMP:
default:
fl->fl_ipsec_spi = 0;
fl->proto = nexthdr;
return;
}
}
}
static inline int xfrm6_garbage_collect(struct dst_ops *ops)
{
struct net *net = container_of(ops, struct net, xfrm.xfrm6_dst_ops);
xfrm6_policy_afinfo.garbage_collect(net);
return (atomic_read(&ops->entries) > ops->gc_thresh * 2);
}
static void xfrm6_update_pmtu(struct dst_entry *dst, u32 mtu)
{
struct xfrm_dst *xdst = (struct xfrm_dst *)dst;
struct dst_entry *path = xdst->route;
path->ops->update_pmtu(path, mtu);
}
static void xfrm6_dst_destroy(struct dst_entry *dst)
{
struct xfrm_dst *xdst = (struct xfrm_dst *)dst;
if (likely(xdst->u.rt6.rt6i_idev))
in6_dev_put(xdst->u.rt6.rt6i_idev);
xfrm_dst_destroy(xdst);
}
static void xfrm6_dst_ifdown(struct dst_entry *dst, struct net_device *dev,
int unregister)
{
struct xfrm_dst *xdst;
if (!unregister)
return;
xdst = (struct xfrm_dst *)dst;
if (xdst->u.rt6.rt6i_idev->dev == dev) {
struct inet6_dev *loopback_idev =
in6_dev_get(dev_net(dev)->loopback_dev);
BUG_ON(!loopback_idev);
do {
in6_dev_put(xdst->u.rt6.rt6i_idev);
xdst->u.rt6.rt6i_idev = loopback_idev;
in6_dev_hold(loopback_idev);
xdst = (struct xfrm_dst *)xdst->u.dst.child;
} while (xdst->u.dst.xfrm);
__in6_dev_put(loopback_idev);
}
xfrm_dst_ifdown(dst, dev);
}
static struct dst_ops xfrm6_dst_ops = {
.family = AF_INET6,
.protocol = cpu_to_be16(ETH_P_IPV6),
.gc = xfrm6_garbage_collect,
.update_pmtu = xfrm6_update_pmtu,
.destroy = xfrm6_dst_destroy,
.ifdown = xfrm6_dst_ifdown,
.local_out = __ip6_local_out,
.gc_thresh = 1024,
.entries = ATOMIC_INIT(0),
};
static struct xfrm_policy_afinfo xfrm6_policy_afinfo = {
.family = AF_INET6,
.dst_ops = &xfrm6_dst_ops,
.dst_lookup = xfrm6_dst_lookup,
.get_saddr = xfrm6_get_saddr,
.find_bundle = __xfrm6_find_bundle,
.decode_session = _decode_session6,
.get_tos = xfrm6_get_tos,
.init_path = xfrm6_init_path,
.fill_dst = xfrm6_fill_dst,
};
static int __init xfrm6_policy_init(void)
{
return xfrm_policy_register_afinfo(&xfrm6_policy_afinfo);
}
static void xfrm6_policy_fini(void)
{
xfrm_policy_unregister_afinfo(&xfrm6_policy_afinfo);
}
#ifdef CONFIG_SYSCTL
static struct ctl_table xfrm6_policy_table[] = {
{
.procname = "xfrm6_gc_thresh",
.data = &init_net.xfrm.xfrm6_dst_ops.gc_thresh,
.maxlen = sizeof(int),
.mode = 0644,
.proc_handler = proc_dointvec,
},
{ }
};
static struct ctl_table_header *sysctl_hdr;
#endif
int __init xfrm6_init(void)
{
int ret;
unsigned int gc_thresh;
/*
* We need a good default value for the xfrm6 gc threshold.
* In ipv4 we set it to the route hash table size * 8, which
* is half the size of the maximaum route cache for ipv4. It
* would be good to do the same thing for v6, except the table is
* constructed differently here. Here each table for a net namespace
* can have FIB_TABLE_HASHSZ entries, so lets go with the same
* computation that we used for ipv4 here. Also, lets keep the initial
* gc_thresh to a minimum of 1024, since, the ipv6 route cache defaults
* to that as a minimum as well
*/
gc_thresh = FIB6_TABLE_HASHSZ * 8;
xfrm6_dst_ops.gc_thresh = (gc_thresh < 1024) ? 1024 : gc_thresh;
ret = xfrm6_policy_init();
if (ret)
goto out;
ret = xfrm6_state_init();
if (ret)
goto out_policy;
#ifdef CONFIG_SYSCTL
sysctl_hdr = register_net_sysctl_table(&init_net, net_ipv6_ctl_path,
xfrm6_policy_table);
#endif
out:
return ret;
out_policy:
xfrm6_policy_fini();
goto out;
}
void xfrm6_fini(void)
{
#ifdef CONFIG_SYSCTL
if (sysctl_hdr)
unregister_net_sysctl_table(sysctl_hdr);
#endif
//xfrm6_input_fini();
xfrm6_policy_fini();
xfrm6_state_fini();
}