BACKPORT: xfrm: Add virtual xfrm interfaces
This patch adds support for virtual xfrm interfaces.
Packets that are routed through such an interface
are guaranteed to be IPsec transformed or dropped.
It is a generic virtual interface that ensures IPsec
transformation, no need to know what happens behind
the interface. This means that we can tunnel IPv4 and
IPv6 through the same interface and support all xfrm
modes (tunnel, transport and beet) on it.
Co-developed-by: Lorenzo Colitti <lorenzo@google.com>
Co-developed-by: Benedict Wong <benedictwong@google.com>
Signed-off-by: Lorenzo Colitti <lorenzo@google.com>
Signed-off-by: Benedict Wong <benedictwong@google.com>
Signed-off-by: Steffen Klassert <steffen.klassert@secunet.com>
Acked-by: Shannon Nelson <shannon.nelson@oracle.com>
Tested-by: Benedict Wong <benedictwong@google.com>
Tested-by: Antony Antony <antony@phenome.org>
Reviewed-by: Eyal Birger <eyal.birger@gmail.com>
Conflicts: XFRM device offload not backported, as with per-cpu caching.
Reverted related code.
(cherry picked from commit f203b76d78092faf248db3f851840fbecf80b40e)
Signed-off-by: Benedict Wong <benedictwong@google.com>
Bug: 115914689
Change-Id: Ide3110870740b0f0fe6e5a4409059756ade3c3fb
diff --git a/net/xfrm/xfrm_policy.c b/net/xfrm/xfrm_policy.c
index b7848be..0391f62 100644
--- a/net/xfrm/xfrm_policy.c
+++ b/net/xfrm/xfrm_policy.c
@@ -44,6 +44,9 @@
u8 flags;
};
+static DEFINE_SPINLOCK(xfrm_if_cb_lock);
+static struct xfrm_if_cb const __rcu *xfrm_if_cb __read_mostly;
+
static DEFINE_SPINLOCK(xfrm_policy_afinfo_lock);
static struct xfrm_policy_afinfo __rcu *xfrm_policy_afinfo[NPROTO]
__read_mostly;
@@ -116,7 +119,13 @@
return afinfo;
}
-static void xfrm_policy_put_afinfo(struct xfrm_policy_afinfo *afinfo)
+/* Called with rcu_read_lock(). */
+static const struct xfrm_if_cb *xfrm_if_get_cb(void)
+{
+ return rcu_dereference(xfrm_if_cb);
+}
+
+static void xfrm_policy_put_afinfo(const struct xfrm_policy_afinfo *afinfo)
{
rcu_read_unlock();
}
@@ -2132,6 +2141,10 @@
xflo->dst_orig);
if (IS_ERR(new_xdst)) {
err = PTR_ERR(new_xdst);
+ if (err == -EREMOTE) {
+ xfrm_pols_put(pols, num_pols);
+ return NULL;
+ }
if (err != -EAGAIN)
goto error;
if (oldflo == NULL)
@@ -2244,6 +2257,9 @@
if (IS_ERR(xdst)) {
xfrm_pols_put(pols, num_pols);
err = PTR_ERR(xdst);
+ if (err == -EREMOTE)
+ goto nopol;
+
goto dropdst;
} else if (xdst == NULL) {
num_xfrms = 0;
@@ -2442,13 +2458,21 @@
int __xfrm_decode_session(struct sk_buff *skb, struct flowi *fl,
unsigned int family, int reverse)
{
- struct xfrm_policy_afinfo *afinfo = xfrm_policy_get_afinfo(family);
+ const struct xfrm_policy_afinfo *afinfo = xfrm_policy_get_afinfo(family);
+ const struct xfrm_if_cb *ifcb = xfrm_if_get_cb();
+ struct xfrm_if *xi;
int err;
if (unlikely(afinfo == NULL))
return -EAFNOSUPPORT;
afinfo->decode_session(skb, fl, reverse);
+ if (ifcb) {
+ xi = ifcb->decode_session(skb);
+ if (xi)
+ fl->flowi_xfrm.if_id = xi->p.if_id;
+ }
+
err = security_xfrm_decode_session(skb, &fl->flowi_secid);
xfrm_policy_put_afinfo(afinfo);
return err;
@@ -2913,6 +2937,20 @@
static struct notifier_block xfrm_dev_notifier = {
.notifier_call = xfrm_dev_event,
};
+void xfrm_if_register_cb(const struct xfrm_if_cb *ifcb)
+{
+ spin_lock(&xfrm_if_cb_lock);
+ rcu_assign_pointer(xfrm_if_cb, ifcb);
+ spin_unlock(&xfrm_if_cb_lock);
+}
+EXPORT_SYMBOL(xfrm_if_register_cb);
+
+void xfrm_if_unregister_cb(void)
+{
+ RCU_INIT_POINTER(xfrm_if_cb, NULL);
+ synchronize_rcu();
+}
+EXPORT_SYMBOL(xfrm_if_unregister_cb);
#ifdef CONFIG_XFRM_STATISTICS
static int __net_init xfrm_statistics_init(struct net *net)
@@ -3092,6 +3130,9 @@
register_pernet_subsys(&xfrm_net_ops);
seqcount_init(&xfrm_policy_hash_generation);
xfrm_input_init();
+
+ RCU_INIT_POINTER(xfrm_if_cb, NULL);
+ synchronize_rcu();
}
#ifdef CONFIG_AUDITSYSCALL