From 0b498a52778368ff501557d68c7b50878ab1701e Mon Sep 17 00:00:00 2001 From: Arnd Bergmann Date: Fri, 26 Aug 2016 17:25:45 +0200 Subject: [PATCH] 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 Fixes: 9399ae9a6cb2 ("net_sched: flower: Add vlan support") Cc: Hadar Hen Zion Cc: Jiri Pirko Signed-off-by: David S. Miller --- net/sched/cls_flower.c | 21 +++++++++++---------- 1 file changed, 11 insertions(+), 10 deletions(-) diff --git a/net/sched/cls_flower.c b/net/sched/cls_flower.c index 532ab6751343..cf9ad5b50889 100644 --- a/net/sched/cls_flower.c +++ b/net/sched/cls_flower.c @@ -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) || -- 2.30.2