From: Florian Westphal fw@strlen.de
commit 89259088c1b7fecb43e8e245dc931909132a4e03 upstream
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: 8866df9264a3 ("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 Signed-off-by: Zubin Mithra zsm@chromium.org --- include/linux/netfilter/nf_conntrack_proto_gre.h | 13 +++++++++++++ net/netfilter/nf_conntrack_proto_gre.c | 14 ++------------ net/netfilter/nfnetlink_cttimeout.c | 15 +++++++++++++-- 3 files changed, 28 insertions(+), 14 deletions(-)
diff --git a/include/linux/netfilter/nf_conntrack_proto_gre.h b/include/linux/netfilter/nf_conntrack_proto_gre.h index b8d95564bd53..14edb795ab43 100644 --- a/include/linux/netfilter/nf_conntrack_proto_gre.h +++ b/include/linux/netfilter/nf_conntrack_proto_gre.h @@ -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); diff --git a/net/netfilter/nf_conntrack_proto_gre.c b/net/netfilter/nf_conntrack_proto_gre.c index 650eb4fba2c5..841c472aae1c 100644 --- a/net/netfilter/nf_conntrack_proto_gre.c +++ b/net/netfilter/nf_conntrack_proto_gre.c @@ -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) { @@ -408,6 +396,8 @@ 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; diff --git a/net/netfilter/nfnetlink_cttimeout.c b/net/netfilter/nfnetlink_cttimeout.c index 1dc4ea327cbe..70a7382b9787 100644 --- a/net/netfilter/nfnetlink_cttimeout.c +++ b/net/netfilter/nfnetlink_cttimeout.c @@ -469,7 +469,8 @@ static int cttimeout_default_get(struct net *net, struct sock *ctnl, case IPPROTO_TCP: timeouts = net->ct.nf_ct_proto.tcp.timeouts; break; - case IPPROTO_UDP: + case IPPROTO_UDP: /* fallthrough */ + case IPPROTO_UDPLITE: timeouts = net->ct.nf_ct_proto.udp.timeouts; break; case IPPROTO_DCCP: @@ -483,13 +484,23 @@ static int cttimeout_default_get(struct net *net, struct sock *ctnl, case IPPROTO_SCTP: #ifdef CONFIG_NF_CT_PROTO_SCTP timeouts = net->ct.nf_ct_proto.sctp.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 = &net->ct.nf_ct_proto.generic.timeout; break; default: - WARN_ON_ONCE(1); + WARN_ONCE(1, "Missing timeouts for proto %d", l4proto->l4proto); break; }