netfilter: conntrack: dccp, sctp: handle null timeout argument

commit 1d9a7acd3d1e74c2d150d8934f7f55bed6d70858 upstream.

The timeout pointer can be NULL which means we should modify the
per-nets timeout instead.

All do this, except sctp and dccp which instead give:

general protection fault: 0000 [#1] PREEMPT SMP KASAN
net/netfilter/nf_conntrack_proto_dccp.c:682
 ctnl_timeout_parse_policy+0x150/0x1d0 net/netfilter/nfnetlink_cttimeout.c:67
 cttimeout_default_set+0x150/0x1c0 net/netfilter/nfnetlink_cttimeout.c:368
 nfnetlink_rcv_msg+0xcf2/0xfb0 net/netfilter/nfnetlink.c:229
 netlink_rcv_skb+0x177/0x450 net/netlink/af_netlink.c:2477

Reported-by: syzbot+46a4ad33f345d1dd346e@syzkaller.appspotmail.com
Fixes: c779e84960 ("netfilter: conntrack: remove get_timeout() indirection")
Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Florian Westphal 2020-01-06 23:34:17 +01:00 committed by Greg Kroah-Hartman
parent 46abb2a5cd
commit df39bb2aa9
2 changed files with 6 additions and 0 deletions

View file

@ -687,6 +687,9 @@ static int dccp_timeout_nlattr_to_obj(struct nlattr *tb[],
unsigned int *timeouts = data;
int i;
if (!timeouts)
timeouts = dn->dccp_timeout;
/* set default DCCP timeouts. */
for (i=0; i<CT_DCCP_MAX; i++)
timeouts[i] = dn->dccp_timeout[i];

View file

@ -603,6 +603,9 @@ static int sctp_timeout_nlattr_to_obj(struct nlattr *tb[],
struct nf_sctp_net *sn = sctp_pernet(net);
int i;
if (!timeouts)
timeouts = sn->timeouts;
/* set default SCTP timeouts. */
for (i=0; i<SCTP_CONNTRACK_MAX; i++)
timeouts[i] = sn->timeouts[i];