From 2f0c982df7b146f9aa695ede91b48392ab4c3217 Mon Sep 17 00:00:00 2001 From: Al Viro Date: Mon, 8 Oct 2018 06:22:35 -0400 Subject: [PATCH] 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 Signed-off-by: Al Viro Signed-off-by: Jamal Hadi Salim Signed-off-by: David S. Miller --- net/sched/cls_u32.c | 6 +++++- 1 file changed, 5 insertions(+), 1 deletion(-) diff --git a/net/sched/cls_u32.c b/net/sched/cls_u32.c index 3357331a80a2..ce55eea448a0 100644 --- a/net/sched/cls_u32.c +++ b/net/sched/cls_u32.c @@ -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; } -- 2.39.5