Cc: Julian Anastasov <[email protected]>
Cc: Simon Horman <[email protected]>
Cc: Pablo Neira Ayuso <[email protected]>
Cc: Jozsef Kadlecsik <[email protected]>
Cc: Florian Westphal <[email protected]>
Suggested-by: Julian Anastasov <[email protected]>
Signed-off-by: Alexander Mikhalitsyn <[email protected]>
---
net/netfilter/ipvs/ip_vs_ctl.c | 14 +++++++-------
1 file changed, 7 insertions(+), 7 deletions(-)
diff --git a/net/netfilter/ipvs/ip_vs_ctl.c b/net/netfilter/ipvs/ip_vs_ctl.c
index 50b5dbe40eb8..e122fa367b81 100644
--- a/net/netfilter/ipvs/ip_vs_ctl.c
+++ b/net/netfilter/ipvs/ip_vs_ctl.c
@@ -94,6 +94,7 @@ static void update_defense_level(struct netns_ipvs *ipvs)
{
struct sysinfo i;
int availmem;
+ int amemthresh;
int nomem;
int to_change = -1;
@@ -105,7 +106,8 @@ static void update_defense_level(struct netns_ipvs *ipvs)
/* si_swapinfo(&i); */
/* availmem = availmem - (i.totalswap - i.freeswap); */
- nomem = (availmem < ipvs->sysctl_amemthresh);
+ amemthresh = max(READ_ONCE(ipvs->sysctl_amemthresh), 0);
+ nomem = (availmem < amemthresh);
local_bh_disable();
@@ -145,9 +147,8 @@ static void update_defense_level(struct netns_ipvs *ipvs)
break;
case 1:
if (nomem) {
- ipvs->drop_rate = ipvs->drop_counter
- = ipvs->sysctl_amemthresh /
- (ipvs->sysctl_amemthresh-availmem);
+ ipvs->drop_counter = amemthresh / (amemthresh - availmem);
+ ipvs->drop_rate = ipvs->drop_counter;
ipvs->sysctl_drop_packet = 2;
} else {
ipvs->drop_rate = 0;
@@ -155,9 +156,8 @@ static void update_defense_level(struct netns_ipvs *ipvs)
break;
case 2:
if (nomem) {
- ipvs->drop_rate = ipvs->drop_counter
- = ipvs->sysctl_amemthresh /
- (ipvs->sysctl_amemthresh-availmem);
+ ipvs->drop_counter = amemthresh / (amemthresh - availmem);
+ ipvs->drop_rate = ipvs->drop_counter;
} else {
ipvs->drop_rate = 0;
ipvs->sysctl_drop_packet = 1;
--
2.34.1
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: Julian Anastasov <[email protected]>
Cc: Simon Horman <[email protected]>
Cc: Pablo Neira Ayuso <[email protected]>
Cc: Jozsef Kadlecsik <[email protected]>
Cc: Florian Westphal <[email protected]>
Signed-off-by: Alexander Mikhalitsyn <[email protected]>
---
net/netfilter/ipvs/ip_vs_ctl.c | 19 +++++++++++++++----
1 file changed, 15 insertions(+), 4 deletions(-)
diff --git a/net/netfilter/ipvs/ip_vs_ctl.c b/net/netfilter/ipvs/ip_vs_ctl.c
index e122fa367b81..b6d0dcf3a5c3 100644
--- a/net/netfilter/ipvs/ip_vs_ctl.c
+++ b/net/netfilter/ipvs/ip_vs_ctl.c
@@ -4269,6 +4269,7 @@ static int __net_init ip_vs_control_net_init_sysctl(struct netns_ipvs *ipvs)
struct ctl_table *tbl;
int idx, ret;
size_t ctl_table_size = ARRAY_SIZE(vs_vars);
+ bool unpriv = net->user_ns != &init_user_ns;
atomic_set(&ipvs->dropentry, 0);
spin_lock_init(&ipvs->dropentry_lock);
@@ -4283,10 +4284,6 @@ 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)
- ctl_table_size = 0;
} else
tbl = vs_vars;
/* Initialize sysctl defaults */
@@ -4312,10 +4309,17 @@ static int __net_init ip_vs_control_net_init_sysctl(struct netns_ipvs *ipvs)
ipvs->sysctl_sync_ports = 1;
tbl[idx++].data = &ipvs->sysctl_sync_ports;
tbl[idx++].data = &ipvs->sysctl_sync_persist_mode;
+
ipvs->sysctl_sync_qlen_max = nr_free_buffer_pages() / 32;
+ if (unpriv)
+ tbl[idx].mode = 0444;
tbl[idx++].data = &ipvs->sysctl_sync_qlen_max;
+
ipvs->sysctl_sync_sock_size = 0;
+ if (unpriv)
+ tbl[idx].mode = 0444;
tbl[idx++].data = &ipvs->sysctl_sync_sock_size;
+
tbl[idx++].data = &ipvs->sysctl_cache_bypass;
tbl[idx++].data = &ipvs->sysctl_expire_nodest_conn;
tbl[idx++].data = &ipvs->sysctl_sloppy_tcp;
@@ -4338,15 +4342,22 @@ static int __net_init ip_vs_control_net_init_sysctl(struct netns_ipvs *ipvs)
tbl[idx++].data = &ipvs->sysctl_conn_reuse_mode;
tbl[idx++].data = &ipvs->sysctl_schedule_icmp;
tbl[idx++].data = &ipvs->sysctl_ignore_tunneled;
+
ipvs->sysctl_run_estimation = 1;
+ if (unpriv)
+ tbl[idx].mode = 0444;
tbl[idx].extra2 = ipvs;
tbl[idx++].data = &ipvs->sysctl_run_estimation;
ipvs->est_cpulist_valid = 0;
+ if (unpriv)
+ tbl[idx].mode = 0444;
tbl[idx].extra2 = ipvs;
tbl[idx++].data = &ipvs->sysctl_est_cpulist;
ipvs->sysctl_est_nice = IPVS_EST_NICE;
+ if (unpriv)
+ tbl[idx].mode = 0444;
tbl[idx].extra2 = ipvs;
tbl[idx++].data = &ipvs->sysctl_est_nice;
--
2.34.1
Hello,
On Mon, 6 May 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: Julian Anastasov <[email protected]>
> Cc: Simon Horman <[email protected]>
> Cc: Pablo Neira Ayuso <[email protected]>
> Cc: Jozsef Kadlecsik <[email protected]>
> Cc: Florian Westphal <[email protected]>
> Signed-off-by: Alexander Mikhalitsyn <[email protected]>
Looks good to me for net-next, thanks!
Acked-by: Julian Anastasov <[email protected]>
> ---
> net/netfilter/ipvs/ip_vs_ctl.c | 19 +++++++++++++++----
> 1 file changed, 15 insertions(+), 4 deletions(-)
>
> diff --git a/net/netfilter/ipvs/ip_vs_ctl.c b/net/netfilter/ipvs/ip_vs_ctl.c
> index e122fa367b81..b6d0dcf3a5c3 100644
> --- a/net/netfilter/ipvs/ip_vs_ctl.c
> +++ b/net/netfilter/ipvs/ip_vs_ctl.c
> @@ -4269,6 +4269,7 @@ static int __net_init ip_vs_control_net_init_sysctl(struct netns_ipvs *ipvs)
> struct ctl_table *tbl;
> int idx, ret;
> size_t ctl_table_size = ARRAY_SIZE(vs_vars);
> + bool unpriv = net->user_ns != &init_user_ns;
>
> atomic_set(&ipvs->dropentry, 0);
> spin_lock_init(&ipvs->dropentry_lock);
> @@ -4283,10 +4284,6 @@ 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)
> - ctl_table_size = 0;
> } else
> tbl = vs_vars;
> /* Initialize sysctl defaults */
> @@ -4312,10 +4309,17 @@ static int __net_init ip_vs_control_net_init_sysctl(struct netns_ipvs *ipvs)
> ipvs->sysctl_sync_ports = 1;
> tbl[idx++].data = &ipvs->sysctl_sync_ports;
> tbl[idx++].data = &ipvs->sysctl_sync_persist_mode;
> +
> ipvs->sysctl_sync_qlen_max = nr_free_buffer_pages() / 32;
> + if (unpriv)
> + tbl[idx].mode = 0444;
> tbl[idx++].data = &ipvs->sysctl_sync_qlen_max;
> +
> ipvs->sysctl_sync_sock_size = 0;
> + if (unpriv)
> + tbl[idx].mode = 0444;
> tbl[idx++].data = &ipvs->sysctl_sync_sock_size;
> +
> tbl[idx++].data = &ipvs->sysctl_cache_bypass;
> tbl[idx++].data = &ipvs->sysctl_expire_nodest_conn;
> tbl[idx++].data = &ipvs->sysctl_sloppy_tcp;
> @@ -4338,15 +4342,22 @@ static int __net_init ip_vs_control_net_init_sysctl(struct netns_ipvs *ipvs)
> tbl[idx++].data = &ipvs->sysctl_conn_reuse_mode;
> tbl[idx++].data = &ipvs->sysctl_schedule_icmp;
> tbl[idx++].data = &ipvs->sysctl_ignore_tunneled;
> +
> ipvs->sysctl_run_estimation = 1;
> + if (unpriv)
> + tbl[idx].mode = 0444;
> tbl[idx].extra2 = ipvs;
> tbl[idx++].data = &ipvs->sysctl_run_estimation;
>
> ipvs->est_cpulist_valid = 0;
> + if (unpriv)
> + tbl[idx].mode = 0444;
> tbl[idx].extra2 = ipvs;
> tbl[idx++].data = &ipvs->sysctl_est_cpulist;
>
> ipvs->sysctl_est_nice = IPVS_EST_NICE;
> + if (unpriv)
> + tbl[idx].mode = 0444;
> tbl[idx].extra2 = ipvs;
> tbl[idx++].data = &ipvs->sysctl_est_nice;
>
> --
> 2.34.1
Regards
--
Julian Anastasov <[email protected]>
Hello,
On Mon, 6 May 2024, Alexander Mikhalitsyn wrote:
> Cc: Julian Anastasov <[email protected]>
> Cc: Simon Horman <[email protected]>
> Cc: Pablo Neira Ayuso <[email protected]>
> Cc: Jozsef Kadlecsik <[email protected]>
> Cc: Florian Westphal <[email protected]>
> Suggested-by: Julian Anastasov <[email protected]>
> Signed-off-by: Alexander Mikhalitsyn <[email protected]>
Looks good to me for net-next, thanks!
Acked-by: Julian Anastasov <[email protected]>
> ---
> net/netfilter/ipvs/ip_vs_ctl.c | 14 +++++++-------
> 1 file changed, 7 insertions(+), 7 deletions(-)
>
> diff --git a/net/netfilter/ipvs/ip_vs_ctl.c b/net/netfilter/ipvs/ip_vs_ctl.c
> index 50b5dbe40eb8..e122fa367b81 100644
> --- a/net/netfilter/ipvs/ip_vs_ctl.c
> +++ b/net/netfilter/ipvs/ip_vs_ctl.c
> @@ -94,6 +94,7 @@ static void update_defense_level(struct netns_ipvs *ipvs)
> {
> struct sysinfo i;
> int availmem;
> + int amemthresh;
> int nomem;
> int to_change = -1;
>
> @@ -105,7 +106,8 @@ static void update_defense_level(struct netns_ipvs *ipvs)
> /* si_swapinfo(&i); */
> /* availmem = availmem - (i.totalswap - i.freeswap); */
>
> - nomem = (availmem < ipvs->sysctl_amemthresh);
> + amemthresh = max(READ_ONCE(ipvs->sysctl_amemthresh), 0);
> + nomem = (availmem < amemthresh);
>
> local_bh_disable();
>
> @@ -145,9 +147,8 @@ static void update_defense_level(struct netns_ipvs *ipvs)
> break;
> case 1:
> if (nomem) {
> - ipvs->drop_rate = ipvs->drop_counter
> - = ipvs->sysctl_amemthresh /
> - (ipvs->sysctl_amemthresh-availmem);
> + ipvs->drop_counter = amemthresh / (amemthresh - availmem);
> + ipvs->drop_rate = ipvs->drop_counter;
> ipvs->sysctl_drop_packet = 2;
> } else {
> ipvs->drop_rate = 0;
> @@ -155,9 +156,8 @@ static void update_defense_level(struct netns_ipvs *ipvs)
> break;
> case 2:
> if (nomem) {
> - ipvs->drop_rate = ipvs->drop_counter
> - = ipvs->sysctl_amemthresh /
> - (ipvs->sysctl_amemthresh-availmem);
> + ipvs->drop_counter = amemthresh / (amemthresh - availmem);
> + ipvs->drop_rate = ipvs->drop_counter;
> } else {
> ipvs->drop_rate = 0;
> ipvs->sysctl_drop_packet = 1;
> --
> 2.34.1
Regards
--
Julian Anastasov <[email protected]>
Hello:
This series was applied to netdev/net-next.git (main)
by David S. Miller <[email protected]>:
On Mon, 6 May 2024 16:14:43 +0200 you wrote:
> Cc: Julian Anastasov <[email protected]>
> Cc: Simon Horman <[email protected]>
> Cc: Pablo Neira Ayuso <[email protected]>
> Cc: Jozsef Kadlecsik <[email protected]>
> Cc: Florian Westphal <[email protected]>
> Suggested-by: Julian Anastasov <[email protected]>
> Signed-off-by: Alexander Mikhalitsyn <[email protected]>
>
> [...]
Here is the summary with links:
- [v4,1/2] ipvs: add READ_ONCE barrier for ipvs->sysctl_amemthresh
https://git.kernel.org/netdev/net-next/c/643bb5dbaef7
- [v4,2/2] ipvs: allow some sysctls in non-init user namespaces
https://git.kernel.org/netdev/net-next/c/2b696a2a101d
You are awesome, thank you!
--
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