ip_tunnel: Add sanity checks to ip_tunnel_encap_add_ops()

The symbols are exported and could be used by external modules.

Fixes: a8c5f9 ("ip_tunnel: Ops registration for secondary encap (fou, gue)")
Signed-off-by: Thomas Graf <tgraf@suug.ch>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 6 insertions, 0 deletions

diff --git a/net/ipv4/ip_tunnel.c b/net/ipv4/ip_tunnel.c
index 63e745aadab6..2f498f87e3d8 100644
--- a/net/ipv4/ip_tunnel.c
+++ b/net/ipv4/ip_tunnel.c
@@ -514,6 +514,9 @@ const struct ip_tunnel_encap_ops __rcu *
 int ip_tunnel_encap_add_ops(const struct ip_tunnel_encap_ops *ops,
                             unsigned int num)
 {
+        if (num >= MAX_IPTUN_ENCAP_OPS)
+                return -ERANGE;
+
         return !cmpxchg((const struct ip_tunnel_encap_ops **)
                         &iptun_encaps[num],
                         NULL, ops) ? 0 : -1;
@@ -525,6 +528,9 @@ int ip_tunnel_encap_del_ops(const struct ip_tunnel_encap_ops *ops,
 {
         int ret;
 
+        if (num >= MAX_IPTUN_ENCAP_OPS)
+                return -ERANGE;
+
         ret = (cmpxchg((const struct ip_tunnel_encap_ops **)
                        &iptun_encaps[num],
                        ops, NULL) == ops) ? 0 : -1;