Re: [PATCH net v3] ipvs: fix possible memory leak in ip_vs_control_net_init

Julian Anastasov
2020-11-24T18:09:35Z

Hello,

On Tue, 24 Nov 2020, Wang Hai wrote:

> kmemleak report a memory leak as follows:
>
> BUG: memory leak
> unreferenced object 0xffff8880759ea000 (size 256):
> backtrace:
> [<00000000c0bf2deb>] kmem_cache_zalloc include/linux/slab.h:656 [inline]
> [<00000000c0bf2deb>] __proc_create+0x23d/0x7d0 fs/proc/generic.c:421
> [<000000009d718d02>] proc_create_reg+0x8e/0x140 fs/proc/generic.c:535
> [<0000000097bbfc4f>] proc_create_net_data+0x8c/0x1b0 fs/proc/proc_net.c:126
> [<00000000652480fc>] ip_vs_control_net_init+0x308/0x13a0 net/netfilter/ipvs/ip_vs_ctl.c:4169
> [<000000004c927ebe>] __ip_vs_init+0x211/0x400 net/netfilter/ipvs/ip_vs_core.c:2429
> [<00000000aa6b72d9>] ops_init+0xa8/0x3c0 net/core/net_namespace.c:151
> [<00000000153fd114>] setup_net+0x2de/0x7e0 net/core/net_namespace.c:341
> [<00000000be4e4f07>] copy_net_ns+0x27d/0x530 net/core/net_namespace.c:482
> [<00000000f1c23ec9>] create_new_namespaces+0x382/0xa30 kernel/nsproxy.c:110
> [<00000000098a5757>] copy_namespaces+0x2e6/0x3b0 kernel/nsproxy.c:179
> [<0000000026ce39e9>] copy_process+0x220a/0x5f00 kernel/fork.c:2072
> [<00000000b71f4efe>] _do_fork+0xc7/0xda0 kernel/fork.c:2428
> [<000000002974ee96>] __do_sys_clone3+0x18a/0x280 kernel/fork.c:2703
> [<0000000062ac0a4d>] do_syscall_64+0x33/0x40 arch/x86/entry/common.c:46
> [<0000000093f1ce2c>] entry_SYSCALL_64_after_hwframe+0x44/0xa9
>
> In the error path of ip_vs_control_net_init(), remove_proc_entry() needs
> to be called to remove the added proc entry, otherwise a memory leak
> will occur.
>
> Also, add some '#ifdef CONFIG_PROC_FS' because proc_create_net* return NULL
> when PROC is not used.
>
> Fixes: b17fc9963f83 ("IPVS: netns, ip_vs_stats and its procfs")
> Fixes: 61b1ab4583e2 ("IPVS: netns, add basic init per netns.")
> Reported-by: Hulk Robot <hulkci@huawei.com>
> Signed-off-by: Wang Hai <wanghai38@huawei.com>

Looks good to me, thanks!

Acked-by: Julian Anastasov <ja@ssi.bg>

> ---
> v2->v3: improve code format
> v1->v2: add some '#ifdef CONFIG_PROC_FS' and check the return value of proc_create_net*
> net/netfilter/ipvs/ip_vs_ctl.c | 31 +++++++++++++++++++++++++------
> 1 file changed, 25 insertions(+), 6 deletions(-)
>
> diff --git a/net/netfilter/ipvs/ip_vs_ctl.c b/net/netfilter/ipvs/ip_vs_ctl.c
> index e279ded4e306..d45dbcba8b49 100644
> --- a/net/netfilter/ipvs/ip_vs_ctl.c
> +++ b/net/netfilter/ipvs/ip_vs_ctl.c
> @@ -4167,12 +4167,18 @@ int __net_init ip_vs_control_net_init(struct netns_ipvs *ipvs)
>
> spin_lock_init(&ipvs->tot_stats.lock);
>
> - proc_create_net("ip_vs", 0, ipvs->net->proc_net, &ip_vs_info_seq_ops,
> - sizeof(struct ip_vs_iter));
> - proc_create_net_single("ip_vs_stats", 0, ipvs->net->proc_net,
> - ip_vs_stats_show, NULL);
> - proc_create_net_single("ip_vs_stats_percpu", 0, ipvs->net->proc_net,
> - ip_vs_stats_percpu_show, NULL);
> +#ifdef CONFIG_PROC_FS
> + if (!proc_create_net("ip_vs", 0, ipvs->net->proc_net,
> + &ip_vs_info_seq_ops, sizeof(struct ip_vs_iter)))
> + goto err_vs;
> + if (!proc_create_net_single("ip_vs_stats", 0, ipvs->net->proc_net,
> + ip_vs_stats_show, NULL))
> + goto err_stats;
> + if (!proc_create_net_single("ip_vs_stats_percpu", 0,
> + ipvs->net->proc_net,
> + ip_vs_stats_percpu_show, NULL))
> + goto err_percpu;
> +#endif
>
> if (ip_vs_control_net_init_sysctl(ipvs))
> goto err;
> @@ -4180,6 +4186,17 @@ int __net_init ip_vs_control_net_init(struct netns_ipvs *ipvs)
> return 0;
>
> err:
> +#ifdef CONFIG_PROC_FS
> + remove_proc_entry("ip_vs_stats_percpu", ipvs->net->proc_net);
> +
> +err_percpu:
> + remove_proc_entry("ip_vs_stats", ipvs->net->proc_net);
> +
> +err_stats:
> + remove_proc_entry("ip_vs", ipvs->net->proc_net);
> +
> +err_vs:
> +#endif
> free_percpu(ipvs->tot_stats.cpustats);
> return -ENOMEM;
> }
> @@ -4188,9 +4205,11 @@ void __net_exit ip_vs_control_net_cleanup(struct netns_ipvs *ipvs)
> {
> ip_vs_trash_cleanup(ipvs);
> ip_vs_control_net_cleanup_sysctl(ipvs);
> +#ifdef CONFIG_PROC_FS
> remove_proc_entry("ip_vs_stats_percpu", ipvs->net->proc_net);
> remove_proc_entry("ip_vs_stats", ipvs->net->proc_net);
> remove_proc_entry("ip_vs", ipvs->net->proc_net);
> +#endif
> free_percpu(ipvs->tot_stats.cpustats);
> }
>
> --
> 2.17.1

Regards

--
Julian Anastasov <ja@ssi.bg>