Otherwise, we hit a NULL pointer deference since handlers always assume
default timeout policy is passed.
netlink: 24 bytes leftover after parsing attributes in process `syz-executor2'.
kasan: CONFIG_KASAN_INLINE enabled
kasan: GPF could be caused by NULL-ptr deref or user memory access
general protection fault: 0000 [#1] PREEMPT SMP KASAN
CPU: 0 PID: 9575 Comm: syz-executor1 Not tainted 4.19.0+ #312
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
RIP: 0010:icmp_timeout_obj_to_nlattr+0x77/0x170 net/netfilter/nf_conntrack_proto_icmp.c:297
Fixes: c779e849608a ("netfilter: conntrack: remove get_timeout() indirection")
Reported-by: Eric Dumazet <eric.dumazet@xxxxxxxxx>
Signed-off-by: Pablo Neira Ayuso <pablo@xxxxxxxxxxxxx>
---
net/netfilter/nfnetlink_cttimeout.c | 30 +++++++++++++++++++++++++++++-
1 file changed, 29 insertions(+), 1 deletion(-)
diff --git a/net/netfilter/nfnetlink_cttimeout.c b/net/netfilter/nfnetlink_cttimeout.c
index e7a50af1b3d6..17e471a108a1 100644
--- a/net/netfilter/nfnetlink_cttimeout.c
+++ b/net/netfilter/nfnetlink_cttimeout.c
@@ -384,6 +384,7 @@ cttimeout_default_fill_info(struct net *net, struct sk_buff *skb, u32 portid,
u32 seq, u32 type, int event, u16 l3num,
const struct nf_conntrack_l4proto *l4proto)
{
+ unsigned int *timeouts;
struct nlmsghdr *nlh;
struct nfgenmsg *nfmsg;
unsigned int flags = portid ? NLM_F_MULTI : 0;
@@ -408,7 +409,34 @@ cttimeout_default_fill_info(struct net *net, struct sk_buff *skb, u32 portid,
if (!nest_parms)
goto nla_put_failure;
- ret = l4proto->ctnl_timeout.obj_to_nlattr(skb, NULL);
+ switch (l4proto->l4proto) {
+ case IPPROTO_ICMP:
+ timeouts = &nf_icmp_pernet(net)->timeout;
+ break;
+ case IPPROTO_TCP:
+ timeouts = nf_tcp_pernet(net)->timeouts;
+ break;
+ case IPPROTO_UDP:
+ timeouts = nf_udp_pernet(net)->timeouts;
+ break;
+ case IPPROTO_DCCP:
+ timeouts = nf_dccp_pernet(net)->dccp_timeout;
+ break;
+ case IPPROTO_ICMPV6:
+ timeouts = &nf_icmpv6_pernet(net)->timeout;
+ break;
+ case IPPROTO_SCTP:
+ timeouts = nf_sctp_pernet(net)->timeouts;
+ break;
+ case 255:
+ timeouts = &nf_generic_pernet(net)->timeout;
+ break;
+ default:
+ WARN_ON_ONCE(1);
+ goto nla_put_failure;
+ }
+
+ ret = l4proto->ctnl_timeout.obj_to_nlattr(skb, timeouts);
if (ret < 0)
goto nla_put_failure;
--
2.11.0
