netfilter: ipset: small potential read beyond the end of buffer

We could be reading 8 bytes into a 4 byte buffer here.  It seems
harmless but adding a check is the right thing to do and it silences a
static checker warning.

Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Acked-by: Jozsef Kadlecsik <kadlec@blackhole.kfki.hu>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

diff --git a/net/netfilter/ipset/ip_set_core.c b/net/netfilter/ipset/ip_set_core.c
index 86f9d76b1464b1b0d5e8b5fc9f9c0c129713bd57..d259da3ce67a6b18f6e4a345a5729876e373efc0 100644 (file)
--- a/net/netfilter/ipset/ip_set_core.c
+++ b/net/netfilter/ipset/ip_set_core.c
@@ -1863,6 +1863,12 @@ ip_set_sockfn_get(struct sock *sk, int optval, void __user *user, int *len)
        if (*op < IP_SET_OP_VERSION) {
                /* Check the version at the beginning of operations */
                struct ip_set_req_version *req_version = data;
+
+               if (*len < sizeof(struct ip_set_req_version)) {
+                       ret = -EINVAL;
+                       goto done;
+               }
+
                if (req_version->version != IPSET_PROTOCOL) {
                        ret = -EPROTO;
                        goto done;