networking: Update to register_net_sysctl_sz

Move from register_net_sysctl to register_net_sysctl_sz for all the
networking related files. Do this while making sure to mirror the NULL
assignments with a table_size of zero for the unprivileged users.

We need to move to the new function in preparation for when we change
SIZE_MAX to ARRAY_SIZE() in the register_net_sysctl macro. Failing to do
so would erroneously allow ARRAY_SIZE() to be called on a pointer. We
hold off the SIZE_MAX to ARRAY_SIZE change until we have migrated all
the relevant net sysctl registering functions to register_net_sysctl_sz
in subsequent commits.

An additional size function was added to the following files in order to
calculate the size of an array that is defined in another file:
    include/net/ipv6.h
    net/ipv6/icmp.c
    net/ipv6/route.c
    net/ipv6/sysctl_net_ipv6.c

Signed-off-by: Joel Granados <j.granados@samsung.com>
Signed-off-by: Luis Chamberlain <mcgrof@kernel.org>

5 files changed, 14 insertions, 6 deletions

diff --git a/net/ipv4/devinet.c b/net/ipv4/devinet.c
index 5deac0517ef7..89087844ea6e 100644
--- a/net/ipv4/devinet.c
+++ b/net/ipv4/devinet.c
@@ -2720,7 +2720,8 @@ static __net_init int devinet_init_net(struct net *net)
 		goto err_reg_dflt;
 
 	err = -ENOMEM;
-	forw_hdr = register_net_sysctl(net, "net/ipv4", tbl);
+	forw_hdr = register_net_sysctl_sz(net, "net/ipv4", tbl,
+					  ARRAY_SIZE(ctl_forward_entry));
 	if (!forw_hdr)
 		goto err_reg_ctl;
 	net->ipv4.forw_hdr = forw_hdr;
diff --git a/net/ipv4/ip_fragment.c b/net/ipv4/ip_fragment.c
index 69c00ffdcf3e..a4941f53b523 100644
--- a/net/ipv4/ip_fragment.c
+++ b/net/ipv4/ip_fragment.c
@@ -615,7 +615,8 @@ static int __net_init ip4_frags_ns_ctl_register(struct net *net)
 	table[2].data	= &net->ipv4.fqdir->timeout;
 	table[3].data	= &net->ipv4.fqdir->max_dist;
 
-	hdr = register_net_sysctl(net, "net/ipv4", table);
+	hdr = register_net_sysctl_sz(net, "net/ipv4", table,
+				     ARRAY_SIZE(ip4_frags_ns_ctl_table));
 	if (!hdr)
 		goto err_reg;
 
diff --git a/net/ipv4/route.c b/net/ipv4/route.c
index 98d7e6ba7493..e7e9fba0357a 100644
--- a/net/ipv4/route.c
+++ b/net/ipv4/route.c
@@ -3592,6 +3592,7 @@ static struct ctl_table ipv4_route_netns_table[] = {
 static __net_init int sysctl_route_net_init(struct net *net)
 {
 	struct ctl_table *tbl;
+	size_t table_size = ARRAY_SIZE(ipv4_route_netns_table);
 
 	tbl = ipv4_route_netns_table;
 	if (!net_eq(net, &init_net)) {
@@ -3603,8 +3604,10 @@ static __net_init int sysctl_route_net_init(struct net *net)
 
 		/* Don't export non-whitelisted sysctls to unprivileged users */
 		if (net->user_ns != &init_user_ns) {
-			if (tbl[0].procname != ipv4_route_flush_procname)
+			if (tbl[0].procname != ipv4_route_flush_procname) {
 				tbl[0].procname = NULL;
+				table_size = 0;
+			}
 		}
 
 		/* Update the variables to point into the current struct net
@@ -3615,7 +3618,8 @@ static __net_init int sysctl_route_net_init(struct net *net)
 	}
 	tbl[0].extra1 = net;
 
-	net->ipv4.route_hdr = register_net_sysctl(net, "net/ipv4/route", tbl);
+	net->ipv4.route_hdr = register_net_sysctl_sz(net, "net/ipv4/route",
+						     tbl, table_size);
 	if (!net->ipv4.route_hdr)
 		goto err_reg;
 	return 0;
diff --git a/net/ipv4/sysctl_net_ipv4.c b/net/ipv4/sysctl_net_ipv4.c
index 2afb0870648b..6ac890b4073f 100644
--- a/net/ipv4/sysctl_net_ipv4.c
+++ b/net/ipv4/sysctl_net_ipv4.c
@@ -1519,7 +1519,8 @@ static __net_init int ipv4_sysctl_init_net(struct net *net)
 		}
 	}
 
-	net->ipv4.ipv4_hdr = register_net_sysctl(net, "net/ipv4", table);
+	net->ipv4.ipv4_hdr = register_net_sysctl_sz(net, "net/ipv4", table,
+						    ARRAY_SIZE(ipv4_net_table));
 	if (!net->ipv4.ipv4_hdr)
 		goto err_reg;
 
diff --git a/net/ipv4/xfrm4_policy.c b/net/ipv4/xfrm4_policy.c
index 9403bbaf1b61..57ea394ffa8c 100644
--- a/net/ipv4/xfrm4_policy.c
+++ b/net/ipv4/xfrm4_policy.c
@@ -178,7 +178,8 @@ static __net_init int xfrm4_net_sysctl_init(struct net *net)
 		table[0].data = &net->xfrm.xfrm4_dst_ops.gc_thresh;
 	}
 
-	hdr = register_net_sysctl(net, "net/ipv4", table);
+	hdr = register_net_sysctl_sz(net, "net/ipv4", table,
+				     ARRAY_SIZE(xfrm4_policy_table));
 	if (!hdr)
 		goto err_reg;