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linux-stable/net/netfilter/nf_conntrack_proto_gre.c
David S. Miller c3e5336925 Merge git://git.kernel.org/pub/scm/linux/kernel/git/pablo/nf-next 
Pablo Neira Ayuso says:

====================
Netfilter updates for net-next

The following patchset contains Netfilter updates for net-next:

1) Support for destination MAC in ipset, from Stefano Brivio.

2) Disallow all-zeroes MAC address in ipset, also from Stefano.

3) Add IPSET_CMD_GET_BYNAME and IPSET_CMD_GET_BYINDEX commands,
   introduce protocol version number 7, from Jozsef Kadlecsik.
   A follow up patch to fix ip_set_byindex() is also included
   in this batch.

4) Honor CTA_MARK_MASK from ctnetlink, from Andreas Jaggi.

5) Statify nf_flow_table_iterate(), from Taehee Yoo.

6) Use nf_flow_table_iterate() to simplify garbage collection in
   nf_flow_table logic, also from Taehee Yoo.

7) Don't use _bh variants of call_rcu(), rcu_barrier() and
   synchronize_rcu_bh() in Netfilter, from Paul E. McKenney.

8) Remove NFC_* cache definition from the old caching
   infrastructure.

9) Remove layer 4 port rover in NAT helpers, use random port
   instead, from Florian Westphal.

10) Use strscpy() in ipset, from Qian Cai.

11) Remove NF_NAT_RANGE_PROTO_RANDOM_FULLY branch now that
    random port is allocated by default, from Xiaozhou Liu.

12) Ignore NF_NAT_RANGE_PROTO_RANDOM too, from Florian Westphal.

13) Limit port allocation selection routine in NAT to avoid
    softlockup splats when most ports are in use, from Florian.

14) Remove unused parameters in nf_ct_l4proto_unregister_sysctl()
    from Yafang Shao.

15) Direct call to nf_nat_l4proto_unique_tuple() instead of
    indirection, from Florian Westphal.

16) Several patches to remove all layer 4 NAT indirections,
    remove nf_nat_l4proto struct, from Florian Westphal.

17) Fix RTP/RTCP source port translation when SNAT is in place,
    from Alin Nastac.

18) Selective rule dump per chain, from Phil Sutter.

19) Revisit CLUSTERIP target, this includes a deadlock fix from
    netns path, sleep in atomic, remove bogus WARN_ON_ONCE()
    and disallow mismatching IP address and MAC address.
    Patchset from Taehee Yoo.

20) Update UDP timeout to stream after 2 seconds, from Florian.

21) Shrink UDP established timeout to 120 seconds like TCP timewait.

22) Sysctl knobs to set GRE timeouts, from Yafang Shao.

23) Move seq_print_acct() to conntrack core file, from Florian.

24) Add enum for conntrack sysctl knobs, also from Florian.

25) Place nf_conntrack_acct, nf_conntrack_helper, nf_conntrack_events
    and nf_conntrack_timestamp knobs in the core, from Florian Westphal.
    As a side effect, shrink netns_ct structure by removing obsolete
    sysctl anchors, also from Florian.
====================

Signed-off-by: David S. Miller <davem@davemloft.net>
2018-12-20 18:20:26 -08:00

458 lines
12 KiB
C
Raw Blame History

/*
* ip_conntrack_proto_gre.c - Version 3.0
*
* Connection tracking protocol helper module for GRE.
*
* GRE is a generic encapsulation protocol, which is generally not very
* suited for NAT, as it has no protocol-specific part as port numbers.
*
* It has an optional key field, which may help us distinguishing two
* connections between the same two hosts.
*
* GRE is defined in RFC 1701 and RFC 1702, as well as RFC 2784
*
* PPTP is built on top of a modified version of GRE, and has a mandatory
* field called "CallID", which serves us for the same purpose as the key
* field in plain GRE.
*
* Documentation about PPTP can be found in RFC 2637
*
* (C) 2000-2005 by Harald Welte <laforge@gnumonks.org>
*
* Development of this code funded by Astaro AG (http://www.astaro.com/)
*
* (C) 2006-2012 Patrick McHardy <kaber@trash.net>
*/
#include <linux/module.h>
#include <linux/types.h>
#include <linux/timer.h>
#include <linux/list.h>
#include <linux/seq_file.h>
#include <linux/in.h>
#include <linux/netdevice.h>
#include <linux/skbuff.h>
#include <linux/slab.h>
#include <net/dst.h>
#include <net/net_namespace.h>
#include <net/netns/generic.h>
#include <net/netfilter/nf_conntrack_l4proto.h>
#include <net/netfilter/nf_conntrack_helper.h>
#include <net/netfilter/nf_conntrack_core.h>
#include <net/netfilter/nf_conntrack_timeout.h>
#include <linux/netfilter/nf_conntrack_proto_gre.h>
#include <linux/netfilter/nf_conntrack_pptp.h>
static const unsigned int gre_timeouts[GRE_CT_MAX] = {
[GRE_CT_UNREPLIED] = 30*HZ,
[GRE_CT_REPLIED] = 180*HZ,
};
static unsigned int proto_gre_net_id __read_mostly;
static inline struct netns_proto_gre *gre_pernet(struct net *net)
{
return net_generic(net, proto_gre_net_id);
}
static void nf_ct_gre_keymap_flush(struct net *net)
{
struct netns_proto_gre *net_gre = gre_pernet(net);
struct nf_ct_gre_keymap *km, *tmp;
write_lock_bh(&net_gre->keymap_lock);
list_for_each_entry_safe(km, tmp, &net_gre->keymap_list, list) {
list_del(&km->list);
kfree(km);
}
write_unlock_bh(&net_gre->keymap_lock);
}
static inline int gre_key_cmpfn(const struct nf_ct_gre_keymap *km,
const struct nf_conntrack_tuple *t)
{
return km->tuple.src.l3num == t->src.l3num &&
!memcmp(&km->tuple.src.u3, &t->src.u3, sizeof(t->src.u3)) &&
!memcmp(&km->tuple.dst.u3, &t->dst.u3, sizeof(t->dst.u3)) &&
km->tuple.dst.protonum == t->dst.protonum &&
km->tuple.dst.u.all == t->dst.u.all;
}
/* look up the source key for a given tuple */
static __be16 gre_keymap_lookup(struct net *net, struct nf_conntrack_tuple *t)
{
struct netns_proto_gre *net_gre = gre_pernet(net);
struct nf_ct_gre_keymap *km;
__be16 key = 0;
read_lock_bh(&net_gre->keymap_lock);
list_for_each_entry(km, &net_gre->keymap_list, list) {
if (gre_key_cmpfn(km, t)) {
key = km->tuple.src.u.gre.key;
break;
}
}
read_unlock_bh(&net_gre->keymap_lock);
pr_debug("lookup src key 0x%x for ", key);
nf_ct_dump_tuple(t);
return key;
}
/* add a single keymap entry, associate with specified master ct */
int nf_ct_gre_keymap_add(struct nf_conn *ct, enum ip_conntrack_dir dir,
struct nf_conntrack_tuple *t)
{
struct net *net = nf_ct_net(ct);
struct netns_proto_gre *net_gre = gre_pernet(net);
struct nf_ct_pptp_master *ct_pptp_info = nfct_help_data(ct);
struct nf_ct_gre_keymap **kmp, *km;
kmp = &ct_pptp_info->keymap[dir];
if (*kmp) {
/* check whether it's a retransmission */
read_lock_bh(&net_gre->keymap_lock);
list_for_each_entry(km, &net_gre->keymap_list, list) {
if (gre_key_cmpfn(km, t) && km == *kmp) {
read_unlock_bh(&net_gre->keymap_lock);
return 0;
}
}
read_unlock_bh(&net_gre->keymap_lock);
pr_debug("trying to override keymap_%s for ct %p\n",
dir == IP_CT_DIR_REPLY ? "reply" : "orig", ct);
return -EEXIST;
}
km = kmalloc(sizeof(*km), GFP_ATOMIC);
if (!km)
return -ENOMEM;
memcpy(&km->tuple, t, sizeof(*t));
*kmp = km;
pr_debug("adding new entry %p: ", km);
nf_ct_dump_tuple(&km->tuple);
write_lock_bh(&net_gre->keymap_lock);
list_add_tail(&km->list, &net_gre->keymap_list);
write_unlock_bh(&net_gre->keymap_lock);
return 0;
}
EXPORT_SYMBOL_GPL(nf_ct_gre_keymap_add);
/* destroy the keymap entries associated with specified master ct */
void nf_ct_gre_keymap_destroy(struct nf_conn *ct)
{
struct net *net = nf_ct_net(ct);
struct netns_proto_gre *net_gre = gre_pernet(net);
struct nf_ct_pptp_master *ct_pptp_info = nfct_help_data(ct);
enum ip_conntrack_dir dir;
pr_debug("entering for ct %p\n", ct);
write_lock_bh(&net_gre->keymap_lock);
for (dir = IP_CT_DIR_ORIGINAL; dir < IP_CT_DIR_MAX; dir++) {
if (ct_pptp_info->keymap[dir]) {
pr_debug("removing %p from list\n",
ct_pptp_info->keymap[dir]);
list_del(&ct_pptp_info->keymap[dir]->list);
kfree(ct_pptp_info->keymap[dir]);
ct_pptp_info->keymap[dir] = NULL;
}
}
write_unlock_bh(&net_gre->keymap_lock);
}
EXPORT_SYMBOL_GPL(nf_ct_gre_keymap_destroy);
/* PUBLIC CONNTRACK PROTO HELPER FUNCTIONS */
/* gre hdr info to tuple */
static bool gre_pkt_to_tuple(const struct sk_buff *skb, unsigned int dataoff,
struct net *net, struct nf_conntrack_tuple *tuple)
{
const struct pptp_gre_header *pgrehdr;
struct pptp_gre_header _pgrehdr;
__be16 srckey;
const struct gre_base_hdr *grehdr;
struct gre_base_hdr _grehdr;
/* first only delinearize old RFC1701 GRE header */
grehdr = skb_header_pointer(skb, dataoff, sizeof(_grehdr), &_grehdr);
if (!grehdr || (grehdr->flags & GRE_VERSION) != GRE_VERSION_1) {
/* try to behave like "nf_conntrack_proto_generic" */
tuple->src.u.all = 0;
tuple->dst.u.all = 0;
return true;
}
/* PPTP header is variable length, only need up to the call_id field */
pgrehdr = skb_header_pointer(skb, dataoff, 8, &_pgrehdr);
if (!pgrehdr)
return true;
if (grehdr->protocol != GRE_PROTO_PPP) {
pr_debug("Unsupported GRE proto(0x%x)\n", ntohs(grehdr->protocol));
return false;
}
tuple->dst.u.gre.key = pgrehdr->call_id;
srckey = gre_keymap_lookup(net, tuple);
tuple->src.u.gre.key = srckey;
return true;
}
#ifdef CONFIG_NF_CONNTRACK_PROCFS
/* print private data for conntrack */
static void gre_print_conntrack(struct seq_file *s, struct nf_conn *ct)
{
seq_printf(s, "timeout=%u, stream_timeout=%u ",
(ct->proto.gre.timeout / HZ),
(ct->proto.gre.stream_timeout / HZ));
}
#endif
static unsigned int *gre_get_timeouts(struct net *net)
{
return gre_pernet(net)->gre_timeouts;
}
/* Returns verdict for packet, and may modify conntrack */
static int gre_packet(struct nf_conn *ct,
struct sk_buff *skb,
unsigned int dataoff,
enum ip_conntrack_info ctinfo,
const struct nf_hook_state *state)
{
if (state->pf != NFPROTO_IPV4)
return -NF_ACCEPT;
if (!nf_ct_is_confirmed(ct)) {
unsigned int *timeouts = nf_ct_timeout_lookup(ct);
if (!timeouts)
timeouts = gre_get_timeouts(nf_ct_net(ct));
/* initialize to sane value. Ideally a conntrack helper
* (e.g. in case of pptp) is increasing them */
ct->proto.gre.stream_timeout = timeouts[GRE_CT_REPLIED];
ct->proto.gre.timeout = timeouts[GRE_CT_UNREPLIED];
}
/* If we've seen traffic both ways, this is a GRE connection.
* Extend timeout. */
if (ct->status & IPS_SEEN_REPLY) {
nf_ct_refresh_acct(ct, ctinfo, skb,
ct->proto.gre.stream_timeout);
/* Also, more likely to be important, and not a probe. */
if (!test_and_set_bit(IPS_ASSURED_BIT, &ct->status))
nf_conntrack_event_cache(IPCT_ASSURED, ct);
} else
nf_ct_refresh_acct(ct, ctinfo, skb,
ct->proto.gre.timeout);
return NF_ACCEPT;
}
/* Called when a conntrack entry has already been removed from the hashes
* and is about to be deleted from memory */
static void gre_destroy(struct nf_conn *ct)
{
struct nf_conn *master = ct->master;
pr_debug(" entering\n");
if (!master)
pr_debug("no master !?!\n");
else
nf_ct_gre_keymap_destroy(master);
}
#ifdef CONFIG_NF_CONNTRACK_TIMEOUT
#include <linux/netfilter/nfnetlink.h>
#include <linux/netfilter/nfnetlink_cttimeout.h>
static int gre_timeout_nlattr_to_obj(struct nlattr *tb[],
struct net *net, void *data)
{
unsigned int *timeouts = data;
struct netns_proto_gre *net_gre = gre_pernet(net);
if (!timeouts)
timeouts = gre_get_timeouts(net);
/* set default timeouts for GRE. */
timeouts[GRE_CT_UNREPLIED] = net_gre->gre_timeouts[GRE_CT_UNREPLIED];
timeouts[GRE_CT_REPLIED] = net_gre->gre_timeouts[GRE_CT_REPLIED];
if (tb[CTA_TIMEOUT_GRE_UNREPLIED]) {
timeouts[GRE_CT_UNREPLIED] =
ntohl(nla_get_be32(tb[CTA_TIMEOUT_GRE_UNREPLIED])) * HZ;
}
if (tb[CTA_TIMEOUT_GRE_REPLIED]) {
timeouts[GRE_CT_REPLIED] =
ntohl(nla_get_be32(tb[CTA_TIMEOUT_GRE_REPLIED])) * HZ;
}
return 0;
}
static int
gre_timeout_obj_to_nlattr(struct sk_buff *skb, const void *data)
{
const unsigned int *timeouts = data;
if (nla_put_be32(skb, CTA_TIMEOUT_GRE_UNREPLIED,
htonl(timeouts[GRE_CT_UNREPLIED] / HZ)) ||
nla_put_be32(skb, CTA_TIMEOUT_GRE_REPLIED,
htonl(timeouts[GRE_CT_REPLIED] / HZ)))
goto nla_put_failure;
return 0;
nla_put_failure:
return -ENOSPC;
}
static const struct nla_policy
gre_timeout_nla_policy[CTA_TIMEOUT_GRE_MAX+1] = {
[CTA_TIMEOUT_GRE_UNREPLIED] = { .type = NLA_U32 },
[CTA_TIMEOUT_GRE_REPLIED] = { .type = NLA_U32 },
};
#endif /* CONFIG_NF_CONNTRACK_TIMEOUT */
#ifdef CONFIG_SYSCTL
static struct ctl_table gre_sysctl_table[] = {
{
.procname = "nf_conntrack_gre_timeout",
.maxlen = sizeof(unsigned int),
.mode = 0644,
.proc_handler = proc_dointvec_jiffies,
},
{
.procname = "nf_conntrack_gre_timeout_stream",
.maxlen = sizeof(unsigned int),
.mode = 0644,
.proc_handler = proc_dointvec_jiffies,
},
{}
};
#endif
static int gre_kmemdup_sysctl_table(struct net *net, struct nf_proto_net *nf,
struct netns_proto_gre *net_gre)
{
#ifdef CONFIG_SYSCTL
int i;
if (nf->ctl_table)
return 0;
nf->ctl_table = kmemdup(gre_sysctl_table,
sizeof(gre_sysctl_table),
GFP_KERNEL);
if (!nf->ctl_table)
return -ENOMEM;
for (i = 0; i < GRE_CT_MAX; i++)
nf->ctl_table[i].data = &net_gre->gre_timeouts[i];
#endif
return 0;
}
static int gre_init_net(struct net *net)
{
struct netns_proto_gre *net_gre = gre_pernet(net);
struct nf_proto_net *nf = &net_gre->nf;
int i;
rwlock_init(&net_gre->keymap_lock);
INIT_LIST_HEAD(&net_gre->keymap_list);
for (i = 0; i < GRE_CT_MAX; i++)
net_gre->gre_timeouts[i] = gre_timeouts[i];
return gre_kmemdup_sysctl_table(net, nf, net_gre);
}
/* protocol helper struct */
static const struct nf_conntrack_l4proto nf_conntrack_l4proto_gre4 = {
.l4proto = IPPROTO_GRE,
.pkt_to_tuple = gre_pkt_to_tuple,
#ifdef CONFIG_NF_CONNTRACK_PROCFS
.print_conntrack = gre_print_conntrack,
#endif
.packet = gre_packet,
.destroy = gre_destroy,
.me = THIS_MODULE,
#if IS_ENABLED(CONFIG_NF_CT_NETLINK)
.tuple_to_nlattr = nf_ct_port_tuple_to_nlattr,
.nlattr_tuple_size = nf_ct_port_nlattr_tuple_size,
.nlattr_to_tuple = nf_ct_port_nlattr_to_tuple,
.nla_policy = nf_ct_port_nla_policy,
#endif
#ifdef CONFIG_NF_CONNTRACK_TIMEOUT
.ctnl_timeout = {
.nlattr_to_obj = gre_timeout_nlattr_to_obj,
.obj_to_nlattr = gre_timeout_obj_to_nlattr,
.nlattr_max = CTA_TIMEOUT_GRE_MAX,
.obj_size = sizeof(unsigned int) * GRE_CT_MAX,
.nla_policy = gre_timeout_nla_policy,
},
#endif /* CONFIG_NF_CONNTRACK_TIMEOUT */
.net_id = &proto_gre_net_id,
.init_net = gre_init_net,
};
static int proto_gre_net_init(struct net *net)
{
int ret = 0;
ret = nf_ct_l4proto_pernet_register_one(net,
&nf_conntrack_l4proto_gre4);
if (ret < 0)
pr_err("nf_conntrack_gre4: pernet registration failed.\n");
return ret;
}
static void proto_gre_net_exit(struct net *net)
{
nf_ct_l4proto_pernet_unregister_one(net, &nf_conntrack_l4proto_gre4);
nf_ct_gre_keymap_flush(net);
}
static struct pernet_operations proto_gre_net_ops = {
.init = proto_gre_net_init,
.exit = proto_gre_net_exit,
.id = &proto_gre_net_id,
.size = sizeof(struct netns_proto_gre),
};
static int __init nf_ct_proto_gre_init(void)
{
int ret;
BUILD_BUG_ON(offsetof(struct netns_proto_gre, nf) != 0);
ret = register_pernet_subsys(&proto_gre_net_ops);
if (ret < 0)
goto out_pernet;
ret = nf_ct_l4proto_register_one(&nf_conntrack_l4proto_gre4);
if (ret < 0)
goto out_gre4;
return 0;
out_gre4:
unregister_pernet_subsys(&proto_gre_net_ops);
out_pernet:
return ret;
}
static void __exit nf_ct_proto_gre_fini(void)
{
nf_ct_l4proto_unregister_one(&nf_conntrack_l4proto_gre4);
unregister_pernet_subsys(&proto_gre_net_ops);
}
module_init(nf_ct_proto_gre_init);
module_exit(nf_ct_proto_gre_fini);
MODULE_LICENSE("GPL");
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