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netfilter: nfnetlink_cttimeout: fetch timeouts for udplite and gre, too 

syzbot was able to trigger the WARN in cttimeout_default_get() by
passing UDPLITE as l4protocol.  Alias UDPLITE to UDP, both use
same timeout values.

Furthermore, also fetch GRE timeouts.  GRE is a bit more complicated,
as it still can be a module and its netns_proto_gre struct layout isn't
visible outside of the gre module. Can't move timeouts around, it
appears conntrack sysctl unregister assumes net_generic() returns
nf_proto_net, so we get crash. Expose layout of netns_proto_gre instead.

A followup nf-next patch could make gre tracker be built-in as well
if needed, its not that large.

Last, make the WARN() mention the missing protocol value in case
anything else is missing.

Reported-by: syzbot+2fae8fa157dd92618cae@syzkaller.appspotmail.com
Fixes: 8866df9264 ("netfilter: nfnetlink_cttimeout: pass default timeout policy to obj_to_nlattr")
Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
This commit is contained in:
Florian Westphal 2018-11-17 11:32:29 +01:00 committed by Pablo Neira Ayuso
parent 2a31e4bd9a
commit 89259088c1
3 changed files with 28 additions and 14 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

13
include/linux/netfilter/nf_conntrack_proto_gre.h
View File

@ -21,6 +21,19 @@ struct nf_ct_gre_keymap {
struct nf_conntrack_tuple tuple;
};
enum grep_conntrack {
GRE_CT_UNREPLIED,
GRE_CT_REPLIED,
GRE_CT_MAX
};
struct netns_proto_gre {
struct nf_proto_net nf;
rwlock_t keymap_lock;
struct list_head keymap_list;
unsigned int gre_timeouts[GRE_CT_MAX];
};
/* add new tuple->key_reply pair to keymap */
int nf_ct_gre_keymap_add(struct nf_conn *ct, enum ip_conntrack_dir dir,
struct nf_conntrack_tuple *t);

14
net/netfilter/nf_conntrack_proto_gre.c
View File

@ -43,24 +43,12 @@
#include <linux/netfilter/nf_conntrack_proto_gre.h>
#include <linux/netfilter/nf_conntrack_pptp.h>
enum grep_conntrack {
GRE_CT_UNREPLIED,
GRE_CT_REPLIED,
GRE_CT_MAX
};
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;
struct netns_proto_gre {
struct nf_proto_net nf;
rwlock_t keymap_lock;
struct list_head keymap_list;
unsigned int gre_timeouts[GRE_CT_MAX];
};
static inline struct netns_proto_gre *gre_pernet(struct net *net)
{
@ -402,6 +390,8 @@ 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;

15
net/netfilter/nfnetlink_cttimeout.c
View File

@ -455,7 +455,8 @@ static int cttimeout_default_get(struct net *net, struct sock *ctnl,
case IPPROTO_TCP:
timeouts = nf_tcp_pernet(net)->timeouts;
break;
case IPPROTO_UDP:
case IPPROTO_UDP: /* fallthrough */
case IPPROTO_UDPLITE:
timeouts = nf_udp_pernet(net)->timeouts;
break;
case IPPROTO_DCCP:
@ -469,13 +470,23 @@ static int cttimeout_default_get(struct net *net, struct sock *ctnl,
case IPPROTO_SCTP:
#ifdef CONFIG_NF_CT_PROTO_SCTP
timeouts = nf_sctp_pernet(net)->timeouts;
#endif
break;
case IPPROTO_GRE:
#ifdef CONFIG_NF_CT_PROTO_GRE
if (l4proto->net_id) {
struct netns_proto_gre *net_gre;
net_gre = net_generic(net, *l4proto->net_id);
timeouts = net_gre->gre_timeouts;
}
#endif
break;
case 255:
timeouts = &nf_generic_pernet(net)->timeout;
break;
default:
WARN_ON_ONCE(1);
WARN_ONCE(1, "Missing timeouts for proto %d", l4proto->l4proto);
break;
}