net: sched: cls_u32: make sure that divisor is a power of 2

Tested by modifying iproute2 to allow sending a divisor > 255

Tested-by: Jamal Hadi Salim <jhs@mojatatu.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Jamal Hadi Salim <jhs@mojatatu.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Al Viro 2018-10-08 06:22:35 -04:00 committed by David S. Miller
parent 27594ec4b6
commit 2f0c982df7

View file

@ -994,7 +994,11 @@ static int u32_change(struct net *net, struct sk_buff *in_skb,
if (tb[TCA_U32_DIVISOR]) {
unsigned int divisor = nla_get_u32(tb[TCA_U32_DIVISOR]);
if (--divisor > 0x100) {
if (!is_power_of_2(divisor)) {
NL_SET_ERR_MSG_MOD(extack, "Divisor is not a power of 2");
return -EINVAL;
}
if (divisor-- > 0x100) {
NL_SET_ERR_MSG_MOD(extack, "Exceeded maximum 256 hash buckets");
return -EINVAL;
}