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/netfilter/nf_conntrack_proto_dccp.c b/net/netfilter/nf_conntrack_proto_dccp.c
index 6535326..a8ae287 100644
--- a/net/netfilter/nf_conntrack_proto_dccp.c
+++ b/net/netfilter/nf_conntrack_proto_dccp.c
@@ -815,7 +815,7 @@
};
#endif /* CONFIG_SYSCTL */
-static int dccp_kmemdup_sysctl_table(struct nf_proto_net *pn,
+static int dccp_kmemdup_sysctl_table(struct net *net, struct nf_proto_net *pn,
struct dccp_net *dn)
{
#ifdef CONFIG_SYSCTL
@@ -836,6 +836,10 @@
pn->ctl_table[5].data = &dn->dccp_timeout[CT_DCCP_CLOSING];
pn->ctl_table[6].data = &dn->dccp_timeout[CT_DCCP_TIMEWAIT];
pn->ctl_table[7].data = &dn->dccp_loose;
+
+ /* Don't export sysctls to unprivileged users */
+ if (net->user_ns != &init_user_ns)
+ pn->ctl_table[0].procname = NULL;
#endif
return 0;
}
@@ -857,7 +861,7 @@
dn->dccp_timeout[CT_DCCP_TIMEWAIT] = 2 * DCCP_MSL;
}
- return dccp_kmemdup_sysctl_table(pn, dn);
+ return dccp_kmemdup_sysctl_table(net, pn, dn);
}
static struct nf_conntrack_l4proto dccp_proto4 __read_mostly = {