[RFC PATCH v2] net: Enable some sysctls for the userns root

[RFC PATCH v2] net: Enable some sysctls for the userns root

[cgel.zte]

From: xu xin <xu.xin16@zte.com.cn>

Enabled sysctls include the following changes:
1. net/ipv4/neigh/<if>/*
2. net/ipv6/neigh/<if>/*
3. net/ieee802154/6lowpan/*
4. net/ipv6/route/*
6. net/ipv4/vs/*
7. net/unix/*
8. net/core/xfrm_*

In some scenarios, some userns root have needs to adjust these sysctls
such as sysctls of neighbor in their own netns, but limited just because
they are not init user_ns.

The newly created user namespace OWNS the net namespace, So the root
user inside the user namespace should have rights to access these net
namespace resources.

Signed-off-by: xu xin <xu.xin16@zte.com.cn>
---
 net/core/neighbour.c                | 4 ----
 net/ieee802154/6lowpan/reassembly.c | 4 ----
 net/ipv6/route.c                    | 4 ----
 net/netfilter/ipvs/ip_vs_ctl.c      | 4 ----
 net/netfilter/ipvs/ip_vs_lblc.c     | 4 ----
 net/netfilter/ipvs/ip_vs_lblcr.c    | 3 ---
 net/unix/sysctl_net_unix.c          | 4 ----
 net/xfrm/xfrm_sysctl.c              | 4 ----
 8 files changed, 31 deletions(-)

diff --git a/net/core/neighbour.c b/net/core/neighbour.c
index 0cdd4d9ad942..44d90cc341ea 100644
--- a/net/core/neighbour.c
+++ b/net/core/neighbour.c
@@ -3771,10 +3771,6 @@ int neigh_sysctl_register(struct net_device *dev, struct neigh_parms *p,
 			neigh_proc_base_reachable_time;
 	}
 
-	/* Don't export sysctls to unprivileged users */
-	if (neigh_parms_net(p)->user_ns != &init_user_ns)
-		t->neigh_vars[0].procname = NULL;
-
 	switch (neigh_parms_family(p)) {
 	case AF_INET:
 	      p_name = "ipv4";
diff --git a/net/ieee802154/6lowpan/reassembly.c b/net/ieee802154/6lowpan/reassembly.c
index be6f06adefe0..89cbad6d8368 100644
--- a/net/ieee802154/6lowpan/reassembly.c
+++ b/net/ieee802154/6lowpan/reassembly.c
@@ -366,10 +366,6 @@ static int __net_init lowpan_frags_ns_sysctl_register(struct net *net)
 				GFP_KERNEL);
 		if (table == NULL)
 			goto err_alloc;
-
-		/* Don't export sysctls to unprivileged users */
-		if (net->user_ns != &init_user_ns)
-			table[0].procname = NULL;
 	}
 
 	table[0].data	= &ieee802154_lowpan->fqdir->high_thresh;
diff --git a/net/ipv6/route.c b/net/ipv6/route.c
index f0d29fcb2094..6a0b15d6500e 100644
--- a/net/ipv6/route.c
+++ b/net/ipv6/route.c
@@ -6409,10 +6409,6 @@ struct ctl_table * __net_init ipv6_route_sysctl_init(struct net *net)
 		table[8].data = &net->ipv6.sysctl.ip6_rt_min_advmss;
 		table[9].data = &net->ipv6.sysctl.ip6_rt_gc_min_interval;
 		table[10].data = &net->ipv6.sysctl.skip_notify_on_dev_down;
-
-		/* Don't export sysctls to unprivileged users */
-		if (net->user_ns != &init_user_ns)
-			table[1].procname = NULL;
 	}
 
 	return table;
diff --git a/net/netfilter/ipvs/ip_vs_ctl.c b/net/netfilter/ipvs/ip_vs_ctl.c
index 7f645328b47f..a77c8abf2fc7 100644
--- a/net/netfilter/ipvs/ip_vs_ctl.c
+++ b/net/netfilter/ipvs/ip_vs_ctl.c
@@ -4040,10 +4040,6 @@ 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;
 	} else
 		tbl = vs_vars;
 	/* Initialize sysctl defaults */
diff --git a/net/netfilter/ipvs/ip_vs_lblc.c b/net/netfilter/ipvs/ip_vs_lblc.c
index 7ac7473e3804..567ba33fa5b4 100644
--- a/net/netfilter/ipvs/ip_vs_lblc.c
+++ b/net/netfilter/ipvs/ip_vs_lblc.c
@@ -561,10 +561,6 @@ static int __net_init __ip_vs_lblc_init(struct net *net)
 		if (ipvs->lblc_ctl_table == NULL)
 			return -ENOMEM;
 
-		/* Don't export sysctls to unprivileged users */
-		if (net->user_ns != &init_user_ns)
-			ipvs->lblc_ctl_table[0].procname = NULL;
-
 	} else
 		ipvs->lblc_ctl_table = vs_vars_table;
 	ipvs->sysctl_lblc_expiration = DEFAULT_EXPIRATION;
diff --git a/net/netfilter/ipvs/ip_vs_lblcr.c b/net/netfilter/ipvs/ip_vs_lblcr.c
index 77c323c36a88..a58440a7bf9e 100644
--- a/net/netfilter/ipvs/ip_vs_lblcr.c
+++ b/net/netfilter/ipvs/ip_vs_lblcr.c
@@ -747,9 +747,6 @@ static int __net_init __ip_vs_lblcr_init(struct net *net)
 		if (ipvs->lblcr_ctl_table == NULL)
 			return -ENOMEM;
 
-		/* Don't export sysctls to unprivileged users */
-		if (net->user_ns != &init_user_ns)
-			ipvs->lblcr_ctl_table[0].procname = NULL;
 	} else
 		ipvs->lblcr_ctl_table = vs_vars_table;
 	ipvs->sysctl_lblcr_expiration = DEFAULT_EXPIRATION;
diff --git a/net/unix/sysctl_net_unix.c b/net/unix/sysctl_net_unix.c
index c09bea89151b..01d44e2598e2 100644
--- a/net/unix/sysctl_net_unix.c
+++ b/net/unix/sysctl_net_unix.c
@@ -30,10 +30,6 @@ int __net_init unix_sysctl_register(struct net *net)
 	if (table == NULL)
 		goto err_alloc;
 
-	/* Don't export sysctls to unprivileged users */
-	if (net->user_ns != &init_user_ns)
-		table[0].procname = NULL;
-
 	table[0].data = &net->unx.sysctl_max_dgram_qlen;
 	net->unx.ctl = register_net_sysctl(net, "net/unix", table);
 	if (net->unx.ctl == NULL)
diff --git a/net/xfrm/xfrm_sysctl.c b/net/xfrm/xfrm_sysctl.c
index 0c6c5ef65f9d..a9b7723eb88f 100644
--- a/net/xfrm/xfrm_sysctl.c
+++ b/net/xfrm/xfrm_sysctl.c
@@ -55,10 +55,6 @@ int __net_init xfrm_sysctl_init(struct net *net)
 	table[2].data = &net->xfrm.sysctl_larval_drop;
 	table[3].data = &net->xfrm.sysctl_acq_expires;
 
-	/* Don't export sysctls to unprivileged users */
-	if (net->user_ns != &init_user_ns)
-		table[0].procname = NULL;
-
 	net->xfrm.sysctl_hdr = register_net_sysctl(net, "net/core", table);
 	if (!net->xfrm.sysctl_hdr)
 		goto out_register;
-- 
2.25.1