netdev - [PATCH net-next v2 03/12] net: sched: cls_u32: make sure that divisor is a power of 2

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-Id: <20181008102244.22212-4-jhs@emojatatu.com>
Date:   Mon,  8 Oct 2018 06:22:35 -0400
From:   Jamal Hadi Salim <jhs@...atatu.com>
To:     davem@...emloft.net
Cc:     xiyou.wangcong@...il.com, jiri@...nulli.us, netdev@...r.kernel.org,
        viro@...iv.linux.org.uk, Jamal Hadi Salim <jhs@...atatu.com>
Subject: [PATCH net-next v2 03/12] net: sched: cls_u32: make sure that divisor is a power of 2

From: Al Viro <viro@...iv.linux.org.uk>

Tested by modifying iproute2 to allow sending a divisor > 255

Tested-by: Jamal Hadi Salim <jhs@...atatu.com>
Signed-off-by: Al Viro <viro@...iv.linux.org.uk>
Signed-off-by: Jamal Hadi Salim <jhs@...atatu.com>
---
 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;
 		}
-- 
2.11.0