linux/net/ipv6/mip6.c
Arnaud Ebalard d9a9dc66eb IPv6: fix CoA check in RH2 input handler (mip6_rthdr_input())
The input handler for Type 2 Routing Header (mip6_rthdr_input())
checks if the CoA in the packet matches the CoA in the XFRM state.

Current check is buggy: it compares the adddress in the Type 2
Routing Header, i.e. the HoA, against the expected CoA in the state.
The comparison should be made against the address in the destination
field of the IPv6 header.

The bug remained unnoticed because the main (and possibly only current)
user of the code (UMIP MIPv6 Daemon) initializes the XFRM state with the
unspecified address, i.e. explicitly allows everything.

Yoshifuji-san, can you ack that one?

Signed-off-by: Arnaud Ebalard <arno@natisbad.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
2010-07-18 15:04:33 -07:00

523 lines
13 KiB
C

/*
* Copyright (C)2003-2006 Helsinki University of Technology
* Copyright (C)2003-2006 USAGI/WIDE Project
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*/
/*
* Authors:
* Noriaki TAKAMIYA @USAGI
* Masahide NAKAMURA @USAGI
*/
#include <linux/module.h>
#include <linux/skbuff.h>
#include <linux/time.h>
#include <linux/ipv6.h>
#include <linux/icmpv6.h>
#include <net/sock.h>
#include <net/ipv6.h>
#include <net/ip6_checksum.h>
#include <net/rawv6.h>
#include <net/xfrm.h>
#include <net/mip6.h>
static inline unsigned int calc_padlen(unsigned int len, unsigned int n)
{
return (n - len + 16) & 0x7;
}
static inline void *mip6_padn(__u8 *data, __u8 padlen)
{
if (!data)
return NULL;
if (padlen == 1) {
data[0] = IPV6_TLV_PAD0;
} else if (padlen > 1) {
data[0] = IPV6_TLV_PADN;
data[1] = padlen - 2;
if (padlen > 2)
memset(data+2, 0, data[1]);
}
return data + padlen;
}
static inline void mip6_param_prob(struct sk_buff *skb, u8 code, int pos)
{
icmpv6_send(skb, ICMPV6_PARAMPROB, code, pos);
}
static int mip6_mh_len(int type)
{
int len = 0;
switch (type) {
case IP6_MH_TYPE_BRR:
len = 0;
break;
case IP6_MH_TYPE_HOTI:
case IP6_MH_TYPE_COTI:
case IP6_MH_TYPE_BU:
case IP6_MH_TYPE_BACK:
len = 1;
break;
case IP6_MH_TYPE_HOT:
case IP6_MH_TYPE_COT:
case IP6_MH_TYPE_BERROR:
len = 2;
break;
}
return len;
}
static int mip6_mh_filter(struct sock *sk, struct sk_buff *skb)
{
struct ip6_mh *mh;
if (!pskb_may_pull(skb, (skb_transport_offset(skb)) + 8) ||
!pskb_may_pull(skb, (skb_transport_offset(skb) +
((skb_transport_header(skb)[1] + 1) << 3))))
return -1;
mh = (struct ip6_mh *)skb_transport_header(skb);
if (mh->ip6mh_hdrlen < mip6_mh_len(mh->ip6mh_type)) {
LIMIT_NETDEBUG(KERN_DEBUG "mip6: MH message too short: %d vs >=%d\n",
mh->ip6mh_hdrlen, mip6_mh_len(mh->ip6mh_type));
mip6_param_prob(skb, 0, ((&mh->ip6mh_hdrlen) -
skb_network_header(skb)));
return -1;
}
if (mh->ip6mh_proto != IPPROTO_NONE) {
LIMIT_NETDEBUG(KERN_DEBUG "mip6: MH invalid payload proto = %d\n",
mh->ip6mh_proto);
mip6_param_prob(skb, 0, ((&mh->ip6mh_proto) -
skb_network_header(skb)));
return -1;
}
return 0;
}
struct mip6_report_rate_limiter {
spinlock_t lock;
struct timeval stamp;
int iif;
struct in6_addr src;
struct in6_addr dst;
};
static struct mip6_report_rate_limiter mip6_report_rl = {
.lock = __SPIN_LOCK_UNLOCKED(mip6_report_rl.lock)
};
static int mip6_destopt_input(struct xfrm_state *x, struct sk_buff *skb)
{
struct ipv6hdr *iph = ipv6_hdr(skb);
struct ipv6_destopt_hdr *destopt = (struct ipv6_destopt_hdr *)skb->data;
int err = destopt->nexthdr;
spin_lock(&x->lock);
if (!ipv6_addr_equal(&iph->saddr, (struct in6_addr *)x->coaddr) &&
!ipv6_addr_any((struct in6_addr *)x->coaddr))
err = -ENOENT;
spin_unlock(&x->lock);
return err;
}
/* Destination Option Header is inserted.
* IP Header's src address is replaced with Home Address Option in
* Destination Option Header.
*/
static int mip6_destopt_output(struct xfrm_state *x, struct sk_buff *skb)
{
struct ipv6hdr *iph;
struct ipv6_destopt_hdr *dstopt;
struct ipv6_destopt_hao *hao;
u8 nexthdr;
int len;
skb_push(skb, -skb_network_offset(skb));
iph = ipv6_hdr(skb);
nexthdr = *skb_mac_header(skb);
*skb_mac_header(skb) = IPPROTO_DSTOPTS;
dstopt = (struct ipv6_destopt_hdr *)skb_transport_header(skb);
dstopt->nexthdr = nexthdr;
hao = mip6_padn((char *)(dstopt + 1),
calc_padlen(sizeof(*dstopt), 6));
hao->type = IPV6_TLV_HAO;
BUILD_BUG_ON(sizeof(*hao) != 18);
hao->length = sizeof(*hao) - 2;
len = ((char *)hao - (char *)dstopt) + sizeof(*hao);
memcpy(&hao->addr, &iph->saddr, sizeof(hao->addr));
spin_lock_bh(&x->lock);
memcpy(&iph->saddr, x->coaddr, sizeof(iph->saddr));
spin_unlock_bh(&x->lock);
WARN_ON(len != x->props.header_len);
dstopt->hdrlen = (x->props.header_len >> 3) - 1;
return 0;
}
static inline int mip6_report_rl_allow(struct timeval *stamp,
struct in6_addr *dst,
struct in6_addr *src, int iif)
{
int allow = 0;
spin_lock_bh(&mip6_report_rl.lock);
if (mip6_report_rl.stamp.tv_sec != stamp->tv_sec ||
mip6_report_rl.stamp.tv_usec != stamp->tv_usec ||
mip6_report_rl.iif != iif ||
!ipv6_addr_equal(&mip6_report_rl.src, src) ||
!ipv6_addr_equal(&mip6_report_rl.dst, dst)) {
mip6_report_rl.stamp.tv_sec = stamp->tv_sec;
mip6_report_rl.stamp.tv_usec = stamp->tv_usec;
mip6_report_rl.iif = iif;
ipv6_addr_copy(&mip6_report_rl.src, src);
ipv6_addr_copy(&mip6_report_rl.dst, dst);
allow = 1;
}
spin_unlock_bh(&mip6_report_rl.lock);
return allow;
}
static int mip6_destopt_reject(struct xfrm_state *x, struct sk_buff *skb, struct flowi *fl)
{
struct net *net = xs_net(x);
struct inet6_skb_parm *opt = (struct inet6_skb_parm *)skb->cb;
struct ipv6_destopt_hao *hao = NULL;
struct xfrm_selector sel;
int offset;
struct timeval stamp;
int err = 0;
if (unlikely(fl->proto == IPPROTO_MH &&
fl->fl_mh_type <= IP6_MH_TYPE_MAX))
goto out;
if (likely(opt->dsthao)) {
offset = ipv6_find_tlv(skb, opt->dsthao, IPV6_TLV_HAO);
if (likely(offset >= 0))
hao = (struct ipv6_destopt_hao *)
(skb_network_header(skb) + offset);
}
skb_get_timestamp(skb, &stamp);
if (!mip6_report_rl_allow(&stamp, &ipv6_hdr(skb)->daddr,
hao ? &hao->addr : &ipv6_hdr(skb)->saddr,
opt->iif))
goto out;
memset(&sel, 0, sizeof(sel));
memcpy(&sel.daddr, (xfrm_address_t *)&ipv6_hdr(skb)->daddr,
sizeof(sel.daddr));
sel.prefixlen_d = 128;
memcpy(&sel.saddr, (xfrm_address_t *)&ipv6_hdr(skb)->saddr,
sizeof(sel.saddr));
sel.prefixlen_s = 128;
sel.family = AF_INET6;
sel.proto = fl->proto;
sel.dport = xfrm_flowi_dport(fl);
if (sel.dport)
sel.dport_mask = htons(~0);
sel.sport = xfrm_flowi_sport(fl);
if (sel.sport)
sel.sport_mask = htons(~0);
sel.ifindex = fl->oif;
err = km_report(net, IPPROTO_DSTOPTS, &sel,
(hao ? (xfrm_address_t *)&hao->addr : NULL));
out:
return err;
}
static int mip6_destopt_offset(struct xfrm_state *x, struct sk_buff *skb,
u8 **nexthdr)
{
u16 offset = sizeof(struct ipv6hdr);
struct ipv6_opt_hdr *exthdr =
(struct ipv6_opt_hdr *)(ipv6_hdr(skb) + 1);
const unsigned char *nh = skb_network_header(skb);
unsigned int packet_len = skb->tail - skb->network_header;
int found_rhdr = 0;
*nexthdr = &ipv6_hdr(skb)->nexthdr;
while (offset + 1 <= packet_len) {
switch (**nexthdr) {
case NEXTHDR_HOP:
break;
case NEXTHDR_ROUTING:
found_rhdr = 1;
break;
case NEXTHDR_DEST:
/*
* HAO MUST NOT appear more than once.
* XXX: It is better to try to find by the end of
* XXX: packet if HAO exists.
*/
if (ipv6_find_tlv(skb, offset, IPV6_TLV_HAO) >= 0) {
LIMIT_NETDEBUG(KERN_WARNING "mip6: hao exists already, override\n");
return offset;
}
if (found_rhdr)
return offset;
break;
default:
return offset;
}
offset += ipv6_optlen(exthdr);
*nexthdr = &exthdr->nexthdr;
exthdr = (struct ipv6_opt_hdr *)(nh + offset);
}
return offset;
}
static int mip6_destopt_init_state(struct xfrm_state *x)
{
if (x->id.spi) {
printk(KERN_INFO "%s: spi is not 0: %u\n", __func__,
x->id.spi);
return -EINVAL;
}
if (x->props.mode != XFRM_MODE_ROUTEOPTIMIZATION) {
printk(KERN_INFO "%s: state's mode is not %u: %u\n",
__func__, XFRM_MODE_ROUTEOPTIMIZATION, x->props.mode);
return -EINVAL;
}
x->props.header_len = sizeof(struct ipv6_destopt_hdr) +
calc_padlen(sizeof(struct ipv6_destopt_hdr), 6) +
sizeof(struct ipv6_destopt_hao);
WARN_ON(x->props.header_len != 24);
return 0;
}
/*
* Do nothing about destroying since it has no specific operation for
* destination options header unlike IPsec protocols.
*/
static void mip6_destopt_destroy(struct xfrm_state *x)
{
}
static const struct xfrm_type mip6_destopt_type =
{
.description = "MIP6DESTOPT",
.owner = THIS_MODULE,
.proto = IPPROTO_DSTOPTS,
.flags = XFRM_TYPE_NON_FRAGMENT | XFRM_TYPE_LOCAL_COADDR,
.init_state = mip6_destopt_init_state,
.destructor = mip6_destopt_destroy,
.input = mip6_destopt_input,
.output = mip6_destopt_output,
.reject = mip6_destopt_reject,
.hdr_offset = mip6_destopt_offset,
};
static int mip6_rthdr_input(struct xfrm_state *x, struct sk_buff *skb)
{
struct ipv6hdr *iph = ipv6_hdr(skb);
struct rt2_hdr *rt2 = (struct rt2_hdr *)skb->data;
int err = rt2->rt_hdr.nexthdr;
spin_lock(&x->lock);
if (!ipv6_addr_equal(&iph->daddr, (struct in6_addr *)x->coaddr) &&
!ipv6_addr_any((struct in6_addr *)x->coaddr))
err = -ENOENT;
spin_unlock(&x->lock);
return err;
}
/* Routing Header type 2 is inserted.
* IP Header's dst address is replaced with Routing Header's Home Address.
*/
static int mip6_rthdr_output(struct xfrm_state *x, struct sk_buff *skb)
{
struct ipv6hdr *iph;
struct rt2_hdr *rt2;
u8 nexthdr;
skb_push(skb, -skb_network_offset(skb));
iph = ipv6_hdr(skb);
nexthdr = *skb_mac_header(skb);
*skb_mac_header(skb) = IPPROTO_ROUTING;
rt2 = (struct rt2_hdr *)skb_transport_header(skb);
rt2->rt_hdr.nexthdr = nexthdr;
rt2->rt_hdr.hdrlen = (x->props.header_len >> 3) - 1;
rt2->rt_hdr.type = IPV6_SRCRT_TYPE_2;
rt2->rt_hdr.segments_left = 1;
memset(&rt2->reserved, 0, sizeof(rt2->reserved));
WARN_ON(rt2->rt_hdr.hdrlen != 2);
memcpy(&rt2->addr, &iph->daddr, sizeof(rt2->addr));
spin_lock_bh(&x->lock);
memcpy(&iph->daddr, x->coaddr, sizeof(iph->daddr));
spin_unlock_bh(&x->lock);
return 0;
}
static int mip6_rthdr_offset(struct xfrm_state *x, struct sk_buff *skb,
u8 **nexthdr)
{
u16 offset = sizeof(struct ipv6hdr);
struct ipv6_opt_hdr *exthdr =
(struct ipv6_opt_hdr *)(ipv6_hdr(skb) + 1);
const unsigned char *nh = skb_network_header(skb);
unsigned int packet_len = skb->tail - skb->network_header;
int found_rhdr = 0;
*nexthdr = &ipv6_hdr(skb)->nexthdr;
while (offset + 1 <= packet_len) {
switch (**nexthdr) {
case NEXTHDR_HOP:
break;
case NEXTHDR_ROUTING:
if (offset + 3 <= packet_len) {
struct ipv6_rt_hdr *rt;
rt = (struct ipv6_rt_hdr *)(nh + offset);
if (rt->type != 0)
return offset;
}
found_rhdr = 1;
break;
case NEXTHDR_DEST:
if (ipv6_find_tlv(skb, offset, IPV6_TLV_HAO) >= 0)
return offset;
if (found_rhdr)
return offset;
break;
default:
return offset;
}
offset += ipv6_optlen(exthdr);
*nexthdr = &exthdr->nexthdr;
exthdr = (struct ipv6_opt_hdr *)(nh + offset);
}
return offset;
}
static int mip6_rthdr_init_state(struct xfrm_state *x)
{
if (x->id.spi) {
printk(KERN_INFO "%s: spi is not 0: %u\n", __func__,
x->id.spi);
return -EINVAL;
}
if (x->props.mode != XFRM_MODE_ROUTEOPTIMIZATION) {
printk(KERN_INFO "%s: state's mode is not %u: %u\n",
__func__, XFRM_MODE_ROUTEOPTIMIZATION, x->props.mode);
return -EINVAL;
}
x->props.header_len = sizeof(struct rt2_hdr);
return 0;
}
/*
* Do nothing about destroying since it has no specific operation for routing
* header type 2 unlike IPsec protocols.
*/
static void mip6_rthdr_destroy(struct xfrm_state *x)
{
}
static const struct xfrm_type mip6_rthdr_type =
{
.description = "MIP6RT",
.owner = THIS_MODULE,
.proto = IPPROTO_ROUTING,
.flags = XFRM_TYPE_NON_FRAGMENT | XFRM_TYPE_REMOTE_COADDR,
.init_state = mip6_rthdr_init_state,
.destructor = mip6_rthdr_destroy,
.input = mip6_rthdr_input,
.output = mip6_rthdr_output,
.hdr_offset = mip6_rthdr_offset,
};
static int __init mip6_init(void)
{
printk(KERN_INFO "Mobile IPv6\n");
if (xfrm_register_type(&mip6_destopt_type, AF_INET6) < 0) {
printk(KERN_INFO "%s: can't add xfrm type(destopt)\n", __func__);
goto mip6_destopt_xfrm_fail;
}
if (xfrm_register_type(&mip6_rthdr_type, AF_INET6) < 0) {
printk(KERN_INFO "%s: can't add xfrm type(rthdr)\n", __func__);
goto mip6_rthdr_xfrm_fail;
}
if (rawv6_mh_filter_register(mip6_mh_filter) < 0) {
printk(KERN_INFO "%s: can't add rawv6 mh filter\n", __func__);
goto mip6_rawv6_mh_fail;
}
return 0;
mip6_rawv6_mh_fail:
xfrm_unregister_type(&mip6_rthdr_type, AF_INET6);
mip6_rthdr_xfrm_fail:
xfrm_unregister_type(&mip6_destopt_type, AF_INET6);
mip6_destopt_xfrm_fail:
return -EAGAIN;
}
static void __exit mip6_fini(void)
{
if (rawv6_mh_filter_unregister(mip6_mh_filter) < 0)
printk(KERN_INFO "%s: can't remove rawv6 mh filter\n", __func__);
if (xfrm_unregister_type(&mip6_rthdr_type, AF_INET6) < 0)
printk(KERN_INFO "%s: can't remove xfrm type(rthdr)\n", __func__);
if (xfrm_unregister_type(&mip6_destopt_type, AF_INET6) < 0)
printk(KERN_INFO "%s: can't remove xfrm type(destopt)\n", __func__);
}
module_init(mip6_init);
module_exit(mip6_fini);
MODULE_LICENSE("GPL");
MODULE_ALIAS_XFRM_TYPE(AF_INET6, XFRM_PROTO_DSTOPTS);
MODULE_ALIAS_XFRM_TYPE(AF_INET6, XFRM_PROTO_ROUTING);