net: Don't export sysctls to unprivileged users
In preparation for supporting the creation of network namespaces
by unprivileged users, modify all of the per net sysctl exports
and refuse to allow them to unprivileged users.
This makes it safe for unprivileged users in general to access
per net sysctls, and allows sysctls to be exported to unprivileged
users on an individual basis as they are deemed safe.
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/ipv6/sysctl_net_ipv6.c b/net/ipv6/sysctl_net_ipv6.c
index e85c48b..b06fd07 100644
--- a/net/ipv6/sysctl_net_ipv6.c
+++ b/net/ipv6/sysctl_net_ipv6.c
@@ -52,6 +52,10 @@
goto out;
ipv6_table[0].data = &net->ipv6.sysctl.bindv6only;
+ /* Don't export sysctls to unprivileged users */
+ if (net->user_ns != &init_user_ns)
+ ipv6_table[0].procname = NULL;
+
ipv6_route_table = ipv6_route_sysctl_init(net);
if (!ipv6_route_table)
goto out_ipv6_table;