linux/net/ipv4/xfrm4_state.c
Hannes Frederic Sowa 628e341f31 xfrm: make local error reporting more robust
In xfrm4 and xfrm6 we need to take care about sockets of the other
address family. This could happen because a 6in4 or 4in6 tunnel could
get protected by ipsec.

Because we don't want to have a run-time dependency on ipv6 when only
using ipv4 xfrm we have to embed a pointer to the correct local_error
function in xfrm_state_afinet and look it up when returning an error
depending on the socket address family.

Thanks to vi0ss for the great bug report:
<https://bugzilla.kernel.org/show_bug.cgi?id=58691>

v2:
a) fix two more unsafe interpretations of skb->sk as ipv6 socket
   (xfrm6_local_dontfrag and __xfrm6_output)
v3:
a) add an EXPORT_SYMBOL_GPL(xfrm_local_error) to fix a link error when
   building ipv6 as a module (thanks to Steffen Klassert)

Reported-by: <vi0oss@gmail.com>
Cc: Steffen Klassert <steffen.klassert@secunet.com>
Signed-off-by: Hannes Frederic Sowa <hannes@stressinduktion.org>
Signed-off-by: Steffen Klassert <steffen.klassert@secunet.com>
2013-08-14 13:07:12 +02:00

101 lines
2.4 KiB
C

/*
* xfrm4_state.c
*
* Changes:
* YOSHIFUJI Hideaki @USAGI
* Split up af-specific portion
*
*/
#include <net/ip.h>
#include <net/xfrm.h>
#include <linux/pfkeyv2.h>
#include <linux/ipsec.h>
#include <linux/netfilter_ipv4.h>
#include <linux/export.h>
static int xfrm4_init_flags(struct xfrm_state *x)
{
if (ipv4_config.no_pmtu_disc)
x->props.flags |= XFRM_STATE_NOPMTUDISC;
return 0;
}
static void
__xfrm4_init_tempsel(struct xfrm_selector *sel, const struct flowi *fl)
{
const struct flowi4 *fl4 = &fl->u.ip4;
sel->daddr.a4 = fl4->daddr;
sel->saddr.a4 = fl4->saddr;
sel->dport = xfrm_flowi_dport(fl, &fl4->uli);
sel->dport_mask = htons(0xffff);
sel->sport = xfrm_flowi_sport(fl, &fl4->uli);
sel->sport_mask = htons(0xffff);
sel->family = AF_INET;
sel->prefixlen_d = 32;
sel->prefixlen_s = 32;
sel->proto = fl4->flowi4_proto;
sel->ifindex = fl4->flowi4_oif;
}
static void
xfrm4_init_temprop(struct xfrm_state *x, const struct xfrm_tmpl *tmpl,
const xfrm_address_t *daddr, const xfrm_address_t *saddr)
{
x->id = tmpl->id;
if (x->id.daddr.a4 == 0)
x->id.daddr.a4 = daddr->a4;
x->props.saddr = tmpl->saddr;
if (x->props.saddr.a4 == 0)
x->props.saddr.a4 = saddr->a4;
x->props.mode = tmpl->mode;
x->props.reqid = tmpl->reqid;
x->props.family = AF_INET;
}
int xfrm4_extract_header(struct sk_buff *skb)
{
const struct iphdr *iph = ip_hdr(skb);
XFRM_MODE_SKB_CB(skb)->ihl = sizeof(*iph);
XFRM_MODE_SKB_CB(skb)->id = iph->id;
XFRM_MODE_SKB_CB(skb)->frag_off = iph->frag_off;
XFRM_MODE_SKB_CB(skb)->tos = iph->tos;
XFRM_MODE_SKB_CB(skb)->ttl = iph->ttl;
XFRM_MODE_SKB_CB(skb)->optlen = iph->ihl * 4 - sizeof(*iph);
memset(XFRM_MODE_SKB_CB(skb)->flow_lbl, 0,
sizeof(XFRM_MODE_SKB_CB(skb)->flow_lbl));
return 0;
}
static struct xfrm_state_afinfo xfrm4_state_afinfo = {
.family = AF_INET,
.proto = IPPROTO_IPIP,
.eth_proto = htons(ETH_P_IP),
.owner = THIS_MODULE,
.init_flags = xfrm4_init_flags,
.init_tempsel = __xfrm4_init_tempsel,
.init_temprop = xfrm4_init_temprop,
.output = xfrm4_output,
.output_finish = xfrm4_output_finish,
.extract_input = xfrm4_extract_input,
.extract_output = xfrm4_extract_output,
.transport_finish = xfrm4_transport_finish,
.local_error = xfrm4_local_error,
};
void __init xfrm4_state_init(void)
{
xfrm_state_register_afinfo(&xfrm4_state_afinfo);
}
#if 0
void __exit xfrm4_state_fini(void)
{
xfrm_state_unregister_afinfo(&xfrm4_state_afinfo);
}
#endif /* 0 */