LVS
lvs-devel
Google
 
Web LinuxVirtualServer.org

Re: [PATCH net-next v3 2/2] ipvs: allow some sysctls in non-init user na

To: Alexander Mikhalitsyn <aleksandr.mikhalitsyn@xxxxxxxxxxxxx>
Subject: Re: [PATCH net-next v3 2/2] ipvs: allow some sysctls in non-init user namespaces
Cc: horms@xxxxxxxxxxxx, netdev@xxxxxxxxxxxxxxx, lvs-devel@xxxxxxxxxxxxxxx, netfilter-devel@xxxxxxxxxxxxxxx, linux-kernel@xxxxxxxxxxxxxxx, Stéphane Graber <stgraber@xxxxxxxxxxxx>, Christian Brauner <brauner@xxxxxxxxxx>, Pablo Neira Ayuso <pablo@xxxxxxxxxxxxx>, Jozsef Kadlecsik <kadlec@xxxxxxxxxxxxx>, Florian Westphal <fw@xxxxxxxxx>
From: Julian Anastasov <ja@xxxxxx>
Date: Fri, 3 May 2024 16:06:24 +0300 (EEST)
        Hello,

On Thu, 18 Apr 2024, Alexander Mikhalitsyn wrote:

> Let's make all IPVS sysctls writtable even when
> network namespace is owned by non-initial user namespace.
> 
> Let's make a few sysctls to be read-only for non-privileged users:
> - sync_qlen_max
> - sync_sock_size
> - run_estimation
> - est_cpulist
> - est_nice
> 
> I'm trying to be conservative with this to prevent
> introducing any security issues in there. Maybe,
> we can allow more sysctls to be writable, but let's
> do this on-demand and when we see real use-case.
> 
> This patch is motivated by user request in the LXC
> project [1]. Having this can help with running some
> Kubernetes [2] or Docker Swarm [3] workloads inside the system
> containers.
> 
> Link: https://github.com/lxc/lxc/issues/4278 [1]
> Link: 
> https://github.com/kubernetes/kubernetes/blob/b722d017a34b300a2284b890448e5a605f21d01e/pkg/proxy/ipvs/proxier.go#L103
>  [2]
> Link: 
> https://github.com/moby/libnetwork/blob/3797618f9a38372e8107d8c06f6ae199e1133ae8/osl/namespace_linux.go#L682
>  [3]
> 
> Cc: Stéphane Graber <stgraber@xxxxxxxxxxxx>
> Cc: Christian Brauner <brauner@xxxxxxxxxx>
> Cc: Julian Anastasov <ja@xxxxxx>
> Cc: Simon Horman <horms@xxxxxxxxxxxx>
> Cc: Pablo Neira Ayuso <pablo@xxxxxxxxxxxxx>
> Cc: Jozsef Kadlecsik <kadlec@xxxxxxxxxxxxx>
> Cc: Florian Westphal <fw@xxxxxxxxx>
> Signed-off-by: Alexander Mikhalitsyn <aleksandr.mikhalitsyn@xxxxxxxxxxxxx>
> ---
>  net/netfilter/ipvs/ip_vs_ctl.c | 21 +++++++++++++++------
>  1 file changed, 15 insertions(+), 6 deletions(-)
> 
> diff --git a/net/netfilter/ipvs/ip_vs_ctl.c b/net/netfilter/ipvs/ip_vs_ctl.c
> index 32be24f0d4e4..c3ba71aa2654 100644
> --- a/net/netfilter/ipvs/ip_vs_ctl.c
> +++ b/net/netfilter/ipvs/ip_vs_ctl.c

...

> @@ -4284,12 +4285,6 @@ static int __net_init 
> ip_vs_control_net_init_sysctl(struct netns_ipvs *ipvs)
>               tbl = kmemdup(vs_vars, sizeof(vs_vars), GFP_KERNEL);
>               if (tbl == NULL)
>                       return -ENOMEM;
> -
> -             /* Don't export sysctls to unprivileged users */
> -             if (net->user_ns != &init_user_ns) {
> -                     tbl[0].procname = NULL;
> -                     ctl_table_size = 0;
> -             }
>       } else
>               tbl = vs_vars;
>       /* Initialize sysctl defaults */

        Sorry but you have to send v4 because above if-block was
changed with net-next commit 635470eb0aa7 from today...

Regards

--
Julian Anastasov <ja@xxxxxx>
<Prev in Thread] Current Thread [Next in Thread>