From 73db1b8f2bb6725b7391e85aab41fdf592b3c0c1 Mon Sep 17 00:00:00 2001 From: Tzung-Bi Shih Date: Wed, 19 Apr 2023 13:15:26 +0800 Subject: netfilter: conntrack: fix wrong ct->timeout value (struct nf_conn)->timeout is an interval before the conntrack confirmed. After confirmed, it becomes a timestamp. It is observed that timeout of an unconfirmed conntrack: - Set by calling ctnetlink_change_timeout(). As a result, `nfct_time_stamp` was wrongly added to `ct->timeout` twice. - Get by calling ctnetlink_dump_timeout(). As a result, `nfct_time_stamp` was wrongly subtracted. Call Trace: dump_stack_lvl ctnetlink_dump_timeout __ctnetlink_glue_build ctnetlink_glue_build __nfqnl_enqueue_packet nf_queue nf_hook_slow ip_mc_output ? __pfx_ip_finish_output ip_send_skb ? __pfx_dst_output udp_send_skb udp_sendmsg ? __pfx_ip_generic_getfrag sock_sendmsg Separate the 2 cases in: - Setting `ct->timeout` in __nf_ct_set_timeout(). - Getting `ct->timeout` in ctnetlink_dump_timeout(). Pablo appends: Update ctnetlink to set up the timeout _after_ the IPS_CONFIRMED flag is set on, otherwise conntrack creation via ctnetlink breaks. Note that the problem described in this patch occurs since the introduction of the nfnetlink_queue conntrack support, select a sufficiently old Fixes: tag for -stable kernel to pick up this fix. Fixes: a4b4766c3ceb ("netfilter: nfnetlink_queue: rename related to nfqueue attaching conntrack info") Signed-off-by: Tzung-Bi Shih Signed-off-by: Pablo Neira Ayuso --- net/netfilter/nf_conntrack_netlink.c | 13 +++++++++---- 1 file changed, 9 insertions(+), 4 deletions(-) (limited to 'net/netfilter/nf_conntrack_netlink.c') diff --git a/net/netfilter/nf_conntrack_netlink.c b/net/netfilter/nf_conntrack_netlink.c index d3ee18854698..6f3b23a6653c 100644 --- a/net/netfilter/nf_conntrack_netlink.c +++ b/net/netfilter/nf_conntrack_netlink.c @@ -176,7 +176,12 @@ nla_put_failure: static int ctnetlink_dump_timeout(struct sk_buff *skb, const struct nf_conn *ct, bool skip_zero) { - long timeout = nf_ct_expires(ct) / HZ; + long timeout; + + if (nf_ct_is_confirmed(ct)) + timeout = nf_ct_expires(ct) / HZ; + else + timeout = ct->timeout / HZ; if (skip_zero && timeout == 0) return 0; @@ -2253,9 +2258,6 @@ ctnetlink_create_conntrack(struct net *net, if (!cda[CTA_TIMEOUT]) goto err1; - timeout = (u64)ntohl(nla_get_be32(cda[CTA_TIMEOUT])) * HZ; - __nf_ct_set_timeout(ct, timeout); - rcu_read_lock(); if (cda[CTA_HELP]) { char *helpname = NULL; @@ -2319,6 +2321,9 @@ ctnetlink_create_conntrack(struct net *net, /* we must add conntrack extensions before confirmation. */ ct->status |= IPS_CONFIRMED; + timeout = (u64)ntohl(nla_get_be32(cda[CTA_TIMEOUT])) * HZ; + __nf_ct_set_timeout(ct, timeout); + if (cda[CTA_STATUS]) { err = ctnetlink_change_status(ct, cda); if (err < 0) -- cgit