On Wed, Sep 27, 2023 at 09:03:09PM +0800, xiaolinkui wrote:
> From: Linkui Xiao <xiaolinkui@xxxxxxxxxx>
>
> If the ip_set is not locked during ip_set_test, the following situations
> may occur:
>
> CPU0 CPU1
> ip_rcv->
> ip_rcv_finish->
> ip_local_deliver->
> nf_hook_slow->
> iptable_filter_hook->
> ipt_do_table->
> set_match_v4->
> ip_set_test-> list_set_destroy->
> hash_net4_kadt-> set->data = NULL
Hi,
I'm having a bit of trouble analysing this.
In particular, I'm concerned that in such a scenario set
itself will be also freed, which seems likely to lead to problems.
Can you provide a more complete call stack for CPU1 ?
> h = set->data
> .cidr = INIT_CIDR(h->nets[0].cidr[0], HOST_MASK)
>
> The set->data is empty, continuing to access set->data will result in a
> kernel NULL pointer. The call trace is as follows:
>
> [2350616.024418] Call trace:
> [2350616.024670] hash_net4_kadt+0x38/0x148 [ip_set_hash_net]
> [2350616.025147] ip_set_test+0xbc/0x230 [ip_set]
> [2350616.025549] set_match_v4+0xac/0xd0 [xt_set]
> [2350616.025951] ipt_do_table+0x32c/0x678 [ip_tables]
> [2350616.026391] iptable_filter_hook+0x30/0x40 [iptable_filter]
> [2350616.026905] nf_hook_slow+0x50/0x100
> [2350616.027256] ip_local_deliver+0xd4/0xe8
> [2350616.027616] ip_rcv_finish+0x90/0xb0
> [2350616.027961] ip_rcv+0x50/0xb0
> [2350616.028261] __netif_receive_skb_one_core+0x58/0x68
> [2350616.028716] __netif_receive_skb+0x28/0x80
> [2350616.029098] netif_receive_skb_internal+0x3c/0xa8
> [2350616.029533] napi_gro_receive+0xf8/0x170
> [2350616.029898] receive_buf+0xec/0xa08 [virtio_net]
> [2350616.030323] virtnet_poll+0x144/0x310 [virtio_net]
> [2350616.030761] net_rx_action+0x158/0x3a0
> [2350616.031124] __do_softirq+0x11c/0x33c
> [2350616.031470] irq_exit+0x11c/0x128
> [2350616.031793] __handle_domain_irq+0x6c/0xc0
> [2350616.032172] gic_handle_irq+0x6c/0x170
> [2350616.032528] el1_irq+0xb8/0x140
> [2350616.032835] arch_cpu_idle+0x38/0x1c0
> [2350616.033183] default_idle_call+0x24/0x58
> [2350616.033549] do_idle+0x1a4/0x268
> [2350616.033859] cpu_startup_entry+0x28/0x78
> [2350616.034234] secondary_start_kernel+0x17c/0x1c8
>
> Signed-off-by: Linkui Xiao <xiaolinkui@xxxxxxxxxx>
> ---
> net/netfilter/ipset/ip_set_core.c | 2 ++
> 1 file changed, 2 insertions(+)
>
> diff --git a/net/netfilter/ipset/ip_set_core.c b/net/netfilter/ipset/ip_set_core.c
> index 35d2f9c9ada0..46f4f47e29e4 100644
> --- a/net/netfilter/ipset/ip_set_core.c
> +++ b/net/netfilter/ipset/ip_set_core.c
> @@ -747,7 +747,9 @@ ip_set_test(ip_set_id_t index, const struct sk_buff *skb,
> !(opt->family == set->family || set->family == NFPROTO_UNSPEC))
> return 0;
>
> + ip_set_lock(set);
> ret = set->variant->kadt(set, skb, par, IPSET_TEST, opt);
> + ip_set_unlock(set);
>
> if (ret == -EAGAIN) {
> /* Type requests element to be completed */
> --
> 2.17.1
>
>
