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Commit 24973073 authored by Vasily Averin's avatar Vasily Averin Committed by Greg Kroah-Hartman
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netfilter: ctnetlink: suspicious RCU usage in ctnetlink_dump_helpinfo 



commit c23a9fd209bc6f8c1fa6ee303fdf037d784a1627 upstream.

Two patches listed below removed ctnetlink_dump_helpinfo call from under
rcu_read_lock. Now its rcu_dereference generates following warning:
=============================
WARNING: suspicious RCU usage
5.13.0+ #5 Not tainted
-----------------------------
net/netfilter/nf_conntrack_netlink.c:221 suspicious rcu_dereference_check() usage!

other info that might help us debug this:
rcu_scheduler_active = 2, debug_locks = 1
stack backtrace:
CPU: 1 PID: 2251 Comm: conntrack Not tainted 5.13.0+ #5
Call Trace:
 dump_stack+0x7f/0xa1
 ctnetlink_dump_helpinfo+0x134/0x150 [nf_conntrack_netlink]
 ctnetlink_fill_info+0x2c2/0x390 [nf_conntrack_netlink]
 ctnetlink_dump_table+0x13f/0x370 [nf_conntrack_netlink]
 netlink_dump+0x10c/0x370
 __netlink_dump_start+0x1a7/0x260
 ctnetlink_get_conntrack+0x1e5/0x250 [nf_conntrack_netlink]
 nfnetlink_rcv_msg+0x613/0x993 [nfnetlink]
 netlink_rcv_skb+0x50/0x100
 nfnetlink_rcv+0x55/0x120 [nfnetlink]
 netlink_unicast+0x181/0x260
 netlink_sendmsg+0x23f/0x460
 sock_sendmsg+0x5b/0x60
 __sys_sendto+0xf1/0x160
 __x64_sys_sendto+0x24/0x30
 do_syscall_64+0x36/0x70
 entry_SYSCALL_64_after_hwframe+0x44/0xae

Fixes: 49ca022bccc5 ("netfilter: ctnetlink: don't dump ct extensions of unconfirmed conntracks")
Fixes: 0b35f603 ("netfilter: Remove duplicated rcu_read_lock.")
Signed-off-by: default avatarVasily Averin <vvs@virtuozzo.com>
Reviewed-by: default avatarFlorian Westphal <fw@strlen.de>
Signed-off-by: default avatarPablo Neira Ayuso <pablo@netfilter.org>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent c6f4a711

net/netfilter/nf_conntrack_netlink.c

+3 −0
Original line number Diff line number Diff line
@@ -211,6 +211,7 @@ static int ctnetlink_dump_helpinfo(struct sk_buff *skb, 
	if (!help)

		return 0;



	rcu_read_lock();

	helper = rcu_dereference(help->helper);

	if (!helper)

		goto out;
@@ -226,9 +227,11 @@ static int ctnetlink_dump_helpinfo(struct sk_buff *skb, 


	nla_nest_end(skb, nest_helper);

out:

	rcu_read_unlock();

	return 0;



nla_put_failure:

	rcu_read_unlock();

	return -1;

}