linux/net/ipv6/xfrm6_tunnel.c
Xin Long 7fe94612dd xfrm: interface: fix the priorities for ipip and ipv6 tunnels
As Nicolas noticed in his case, when xfrm_interface module is installed
the standard IP tunnels will break in receiving packets.

This is caused by the IP tunnel handlers with a higher priority in xfrm
interface processing incoming packets by xfrm_input(), which would drop
the packets and return 0 instead when anything wrong happens.

Rather than changing xfrm_input(), this patch is to adjust the priority
for the IP tunnel handlers in xfrm interface, so that the packets would
go to xfrmi's later than the others', as the others' would not drop the
packets when the handlers couldn't process them.

Note that IPCOMP also defines its own IPIP tunnel handler and it calls
xfrm_input() as well, so we must make its priority lower than xfrmi's,
which means having xfrmi loaded would still break IPCOMP. We may seek
another way to fix it in xfrm_input() in the future.

Reported-by: Nicolas Dichtel <nicolas.dichtel@6wind.com>
Tested-by: Nicolas Dichtel <nicolas.dichtel@6wind.com>
Fixes: da9bbf0598 ("xfrm: interface: support IPIP and IPIP6 tunnels processing with .cb_handler")
FIxes: d7b360c286 ("xfrm: interface: support IP6IP6 and IP6IP tunnels processing with .cb_handler")
Signed-off-by: Xin Long <lucien.xin@gmail.com>
Signed-off-by: Steffen Klassert <steffen.klassert@secunet.com>
2020-10-09 12:29:48 +02:00

403 lines
9.7 KiB
C

// SPDX-License-Identifier: GPL-2.0-or-later
/*
* Copyright (C)2003,2004 USAGI/WIDE Project
*
* Authors Mitsuru KANDA <mk@linux-ipv6.org>
* YOSHIFUJI Hideaki <yoshfuji@linux-ipv6.org>
*
* Based on net/ipv4/xfrm4_tunnel.c
*/
#include <linux/module.h>
#include <linux/xfrm.h>
#include <linux/slab.h>
#include <linux/rculist.h>
#include <net/ip.h>
#include <net/xfrm.h>
#include <net/ipv6.h>
#include <linux/ipv6.h>
#include <linux/icmpv6.h>
#include <linux/mutex.h>
#include <net/netns/generic.h>
#define XFRM6_TUNNEL_SPI_BYADDR_HSIZE 256
#define XFRM6_TUNNEL_SPI_BYSPI_HSIZE 256
#define XFRM6_TUNNEL_SPI_MIN 1
#define XFRM6_TUNNEL_SPI_MAX 0xffffffff
struct xfrm6_tunnel_net {
struct hlist_head spi_byaddr[XFRM6_TUNNEL_SPI_BYADDR_HSIZE];
struct hlist_head spi_byspi[XFRM6_TUNNEL_SPI_BYSPI_HSIZE];
u32 spi;
};
static unsigned int xfrm6_tunnel_net_id __read_mostly;
static inline struct xfrm6_tunnel_net *xfrm6_tunnel_pernet(struct net *net)
{
return net_generic(net, xfrm6_tunnel_net_id);
}
/*
* xfrm_tunnel_spi things are for allocating unique id ("spi")
* per xfrm_address_t.
*/
struct xfrm6_tunnel_spi {
struct hlist_node list_byaddr;
struct hlist_node list_byspi;
xfrm_address_t addr;
u32 spi;
refcount_t refcnt;
struct rcu_head rcu_head;
};
static DEFINE_SPINLOCK(xfrm6_tunnel_spi_lock);
static struct kmem_cache *xfrm6_tunnel_spi_kmem __read_mostly;
static inline unsigned int xfrm6_tunnel_spi_hash_byaddr(const xfrm_address_t *addr)
{
unsigned int h;
h = ipv6_addr_hash((const struct in6_addr *)addr);
h ^= h >> 16;
h ^= h >> 8;
h &= XFRM6_TUNNEL_SPI_BYADDR_HSIZE - 1;
return h;
}
static inline unsigned int xfrm6_tunnel_spi_hash_byspi(u32 spi)
{
return spi % XFRM6_TUNNEL_SPI_BYSPI_HSIZE;
}
static struct xfrm6_tunnel_spi *__xfrm6_tunnel_spi_lookup(struct net *net, const xfrm_address_t *saddr)
{
struct xfrm6_tunnel_net *xfrm6_tn = xfrm6_tunnel_pernet(net);
struct xfrm6_tunnel_spi *x6spi;
hlist_for_each_entry_rcu(x6spi,
&xfrm6_tn->spi_byaddr[xfrm6_tunnel_spi_hash_byaddr(saddr)],
list_byaddr, lockdep_is_held(&xfrm6_tunnel_spi_lock)) {
if (xfrm6_addr_equal(&x6spi->addr, saddr))
return x6spi;
}
return NULL;
}
__be32 xfrm6_tunnel_spi_lookup(struct net *net, const xfrm_address_t *saddr)
{
struct xfrm6_tunnel_spi *x6spi;
u32 spi;
rcu_read_lock_bh();
x6spi = __xfrm6_tunnel_spi_lookup(net, saddr);
spi = x6spi ? x6spi->spi : 0;
rcu_read_unlock_bh();
return htonl(spi);
}
EXPORT_SYMBOL(xfrm6_tunnel_spi_lookup);
static int __xfrm6_tunnel_spi_check(struct net *net, u32 spi)
{
struct xfrm6_tunnel_net *xfrm6_tn = xfrm6_tunnel_pernet(net);
struct xfrm6_tunnel_spi *x6spi;
int index = xfrm6_tunnel_spi_hash_byspi(spi);
hlist_for_each_entry(x6spi,
&xfrm6_tn->spi_byspi[index],
list_byspi) {
if (x6spi->spi == spi)
return -1;
}
return index;
}
static u32 __xfrm6_tunnel_alloc_spi(struct net *net, xfrm_address_t *saddr)
{
struct xfrm6_tunnel_net *xfrm6_tn = xfrm6_tunnel_pernet(net);
u32 spi;
struct xfrm6_tunnel_spi *x6spi;
int index;
if (xfrm6_tn->spi < XFRM6_TUNNEL_SPI_MIN ||
xfrm6_tn->spi >= XFRM6_TUNNEL_SPI_MAX)
xfrm6_tn->spi = XFRM6_TUNNEL_SPI_MIN;
else
xfrm6_tn->spi++;
for (spi = xfrm6_tn->spi; spi <= XFRM6_TUNNEL_SPI_MAX; spi++) {
index = __xfrm6_tunnel_spi_check(net, spi);
if (index >= 0)
goto alloc_spi;
if (spi == XFRM6_TUNNEL_SPI_MAX)
break;
}
for (spi = XFRM6_TUNNEL_SPI_MIN; spi < xfrm6_tn->spi; spi++) {
index = __xfrm6_tunnel_spi_check(net, spi);
if (index >= 0)
goto alloc_spi;
}
spi = 0;
goto out;
alloc_spi:
xfrm6_tn->spi = spi;
x6spi = kmem_cache_alloc(xfrm6_tunnel_spi_kmem, GFP_ATOMIC);
if (!x6spi)
goto out;
memcpy(&x6spi->addr, saddr, sizeof(x6spi->addr));
x6spi->spi = spi;
refcount_set(&x6spi->refcnt, 1);
hlist_add_head_rcu(&x6spi->list_byspi, &xfrm6_tn->spi_byspi[index]);
index = xfrm6_tunnel_spi_hash_byaddr(saddr);
hlist_add_head_rcu(&x6spi->list_byaddr, &xfrm6_tn->spi_byaddr[index]);
out:
return spi;
}
__be32 xfrm6_tunnel_alloc_spi(struct net *net, xfrm_address_t *saddr)
{
struct xfrm6_tunnel_spi *x6spi;
u32 spi;
spin_lock_bh(&xfrm6_tunnel_spi_lock);
x6spi = __xfrm6_tunnel_spi_lookup(net, saddr);
if (x6spi) {
refcount_inc(&x6spi->refcnt);
spi = x6spi->spi;
} else
spi = __xfrm6_tunnel_alloc_spi(net, saddr);
spin_unlock_bh(&xfrm6_tunnel_spi_lock);
return htonl(spi);
}
EXPORT_SYMBOL(xfrm6_tunnel_alloc_spi);
static void x6spi_destroy_rcu(struct rcu_head *head)
{
kmem_cache_free(xfrm6_tunnel_spi_kmem,
container_of(head, struct xfrm6_tunnel_spi, rcu_head));
}
static void xfrm6_tunnel_free_spi(struct net *net, xfrm_address_t *saddr)
{
struct xfrm6_tunnel_net *xfrm6_tn = xfrm6_tunnel_pernet(net);
struct xfrm6_tunnel_spi *x6spi;
struct hlist_node *n;
spin_lock_bh(&xfrm6_tunnel_spi_lock);
hlist_for_each_entry_safe(x6spi, n,
&xfrm6_tn->spi_byaddr[xfrm6_tunnel_spi_hash_byaddr(saddr)],
list_byaddr)
{
if (xfrm6_addr_equal(&x6spi->addr, saddr)) {
if (refcount_dec_and_test(&x6spi->refcnt)) {
hlist_del_rcu(&x6spi->list_byaddr);
hlist_del_rcu(&x6spi->list_byspi);
call_rcu(&x6spi->rcu_head, x6spi_destroy_rcu);
break;
}
}
}
spin_unlock_bh(&xfrm6_tunnel_spi_lock);
}
static int xfrm6_tunnel_output(struct xfrm_state *x, struct sk_buff *skb)
{
skb_push(skb, -skb_network_offset(skb));
return 0;
}
static int xfrm6_tunnel_input(struct xfrm_state *x, struct sk_buff *skb)
{
return skb_network_header(skb)[IP6CB(skb)->nhoff];
}
static int xfrm6_tunnel_rcv(struct sk_buff *skb)
{
struct net *net = dev_net(skb->dev);
const struct ipv6hdr *iph = ipv6_hdr(skb);
__be32 spi;
spi = xfrm6_tunnel_spi_lookup(net, (const xfrm_address_t *)&iph->saddr);
return xfrm6_rcv_spi(skb, IPPROTO_IPV6, spi, NULL);
}
static int xfrm6_tunnel_err(struct sk_buff *skb, struct inet6_skb_parm *opt,
u8 type, u8 code, int offset, __be32 info)
{
/* xfrm6_tunnel native err handling */
switch (type) {
case ICMPV6_DEST_UNREACH:
switch (code) {
case ICMPV6_NOROUTE:
case ICMPV6_ADM_PROHIBITED:
case ICMPV6_NOT_NEIGHBOUR:
case ICMPV6_ADDR_UNREACH:
case ICMPV6_PORT_UNREACH:
default:
break;
}
break;
case ICMPV6_PKT_TOOBIG:
break;
case ICMPV6_TIME_EXCEED:
switch (code) {
case ICMPV6_EXC_HOPLIMIT:
break;
case ICMPV6_EXC_FRAGTIME:
default:
break;
}
break;
case ICMPV6_PARAMPROB:
switch (code) {
case ICMPV6_HDR_FIELD: break;
case ICMPV6_UNK_NEXTHDR: break;
case ICMPV6_UNK_OPTION: break;
}
break;
default:
break;
}
return 0;
}
static int xfrm6_tunnel_init_state(struct xfrm_state *x)
{
if (x->props.mode != XFRM_MODE_TUNNEL)
return -EINVAL;
if (x->encap)
return -EINVAL;
x->props.header_len = sizeof(struct ipv6hdr);
return 0;
}
static void xfrm6_tunnel_destroy(struct xfrm_state *x)
{
struct net *net = xs_net(x);
xfrm6_tunnel_free_spi(net, (xfrm_address_t *)&x->props.saddr);
}
static const struct xfrm_type xfrm6_tunnel_type = {
.description = "IP6IP6",
.owner = THIS_MODULE,
.proto = IPPROTO_IPV6,
.init_state = xfrm6_tunnel_init_state,
.destructor = xfrm6_tunnel_destroy,
.input = xfrm6_tunnel_input,
.output = xfrm6_tunnel_output,
};
static struct xfrm6_tunnel xfrm6_tunnel_handler __read_mostly = {
.handler = xfrm6_tunnel_rcv,
.err_handler = xfrm6_tunnel_err,
.priority = 3,
};
static struct xfrm6_tunnel xfrm46_tunnel_handler __read_mostly = {
.handler = xfrm6_tunnel_rcv,
.err_handler = xfrm6_tunnel_err,
.priority = 3,
};
static int __net_init xfrm6_tunnel_net_init(struct net *net)
{
struct xfrm6_tunnel_net *xfrm6_tn = xfrm6_tunnel_pernet(net);
unsigned int i;
for (i = 0; i < XFRM6_TUNNEL_SPI_BYADDR_HSIZE; i++)
INIT_HLIST_HEAD(&xfrm6_tn->spi_byaddr[i]);
for (i = 0; i < XFRM6_TUNNEL_SPI_BYSPI_HSIZE; i++)
INIT_HLIST_HEAD(&xfrm6_tn->spi_byspi[i]);
xfrm6_tn->spi = 0;
return 0;
}
static void __net_exit xfrm6_tunnel_net_exit(struct net *net)
{
struct xfrm6_tunnel_net *xfrm6_tn = xfrm6_tunnel_pernet(net);
unsigned int i;
xfrm_flush_gc();
xfrm_state_flush(net, 0, false, true);
for (i = 0; i < XFRM6_TUNNEL_SPI_BYADDR_HSIZE; i++)
WARN_ON_ONCE(!hlist_empty(&xfrm6_tn->spi_byaddr[i]));
for (i = 0; i < XFRM6_TUNNEL_SPI_BYSPI_HSIZE; i++)
WARN_ON_ONCE(!hlist_empty(&xfrm6_tn->spi_byspi[i]));
}
static struct pernet_operations xfrm6_tunnel_net_ops = {
.init = xfrm6_tunnel_net_init,
.exit = xfrm6_tunnel_net_exit,
.id = &xfrm6_tunnel_net_id,
.size = sizeof(struct xfrm6_tunnel_net),
};
static int __init xfrm6_tunnel_init(void)
{
int rv;
xfrm6_tunnel_spi_kmem = kmem_cache_create("xfrm6_tunnel_spi",
sizeof(struct xfrm6_tunnel_spi),
0, SLAB_HWCACHE_ALIGN,
NULL);
if (!xfrm6_tunnel_spi_kmem)
return -ENOMEM;
rv = register_pernet_subsys(&xfrm6_tunnel_net_ops);
if (rv < 0)
goto out_pernet;
rv = xfrm_register_type(&xfrm6_tunnel_type, AF_INET6);
if (rv < 0)
goto out_type;
rv = xfrm6_tunnel_register(&xfrm6_tunnel_handler, AF_INET6);
if (rv < 0)
goto out_xfrm6;
rv = xfrm6_tunnel_register(&xfrm46_tunnel_handler, AF_INET);
if (rv < 0)
goto out_xfrm46;
return 0;
out_xfrm46:
xfrm6_tunnel_deregister(&xfrm6_tunnel_handler, AF_INET6);
out_xfrm6:
xfrm_unregister_type(&xfrm6_tunnel_type, AF_INET6);
out_type:
unregister_pernet_subsys(&xfrm6_tunnel_net_ops);
out_pernet:
kmem_cache_destroy(xfrm6_tunnel_spi_kmem);
return rv;
}
static void __exit xfrm6_tunnel_fini(void)
{
xfrm6_tunnel_deregister(&xfrm46_tunnel_handler, AF_INET);
xfrm6_tunnel_deregister(&xfrm6_tunnel_handler, AF_INET6);
xfrm_unregister_type(&xfrm6_tunnel_type, AF_INET6);
unregister_pernet_subsys(&xfrm6_tunnel_net_ops);
/* Someone maybe has gotten the xfrm6_tunnel_spi.
* So need to wait it.
*/
rcu_barrier();
kmem_cache_destroy(xfrm6_tunnel_spi_kmem);
}
module_init(xfrm6_tunnel_init);
module_exit(xfrm6_tunnel_fini);
MODULE_LICENSE("GPL");
MODULE_ALIAS_XFRM_TYPE(AF_INET6, XFRM_PROTO_IPV6);