net_sched: fix use of uninitialized ethertype variable in cls_flower

The addition of VLAN support caused a possible use of uninitialized
data if we encounter a zero TCA_FLOWER_KEY_ETH_TYPE key, as pointed
out by "gcc -Wmaybe-uninitialized":

net/sched/cls_flower.c: In function 'fl_change':
net/sched/cls_flower.c:366:22: error: 'ethertype' may be used uninitialized in this function [-Werror=maybe-uninitialized]

This changes the code to only set the ethertype field if it
was nonzero, as before the patch.

Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Fixes: 9399ae9a6c ("net_sched: flower: Add vlan support")
Cc: Hadar Hen Zion <hadarh@mellanox.com>
Cc: Jiri Pirko <jiri@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Arnd Bergmann 2016-08-26 17:25:45 +02:00 committed by David S. Miller
parent f9dc70744d
commit 0b498a5277

View file

@ -353,18 +353,19 @@ static int fl_set_key(struct net *net, struct nlattr **tb,
mask->eth.src, TCA_FLOWER_KEY_ETH_SRC_MASK,
sizeof(key->eth.src));
if (tb[TCA_FLOWER_KEY_ETH_TYPE])
if (tb[TCA_FLOWER_KEY_ETH_TYPE]) {
ethertype = nla_get_be16(tb[TCA_FLOWER_KEY_ETH_TYPE]);
if (ethertype == htons(ETH_P_8021Q)) {
fl_set_key_vlan(tb, &key->vlan, &mask->vlan);
fl_set_key_val(tb, &key->basic.n_proto,
TCA_FLOWER_KEY_VLAN_ETH_TYPE,
&mask->basic.n_proto, TCA_FLOWER_UNSPEC,
sizeof(key->basic.n_proto));
} else {
key->basic.n_proto = ethertype;
mask->basic.n_proto = cpu_to_be16(~0);
if (ethertype == htons(ETH_P_8021Q)) {
fl_set_key_vlan(tb, &key->vlan, &mask->vlan);
fl_set_key_val(tb, &key->basic.n_proto,
TCA_FLOWER_KEY_VLAN_ETH_TYPE,
&mask->basic.n_proto, TCA_FLOWER_UNSPEC,
sizeof(key->basic.n_proto));
} else {
key->basic.n_proto = ethertype;
mask->basic.n_proto = cpu_to_be16(~0);
}
}
if (key->basic.n_proto == htons(ETH_P_IP) ||