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/core/sysctl_net_core.c b/net/core/sysctl_net_core.c
index a7c3684..d1b0804 100644
--- a/net/core/sysctl_net_core.c
+++ b/net/core/sysctl_net_core.c
@@ -216,6 +216,11 @@
goto err_dup;
tbl[0].data = &net->core.sysctl_somaxconn;
+
+ /* Don't export any sysctls to unprivileged users */
+ if (net->user_ns != &init_user_ns) {
+ tbl[0].procname = NULL;
+ }
}
net->core.sysctl_hdr = register_net_sysctl(net, "net/core", tbl);
