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Date:   Mon, 9 Jan 2023 11:48:55 +0000
From:   Gavrilov Ilia <Ilia.Gavrilov@...otecs.ru>
To:     Pablo Neira Ayuso <pablo@...filter.org>
CC:     Jozsef Kadlecsik <kadlec@...filter.org>,
        Florian Westphal <fw@...len.de>,
        "David S. Miller" <davem@...emloft.net>,
        Eric Dumazet <edumazet@...gle.com>,
        Jakub Kicinski <kuba@...nel.org>,
        Paolo Abeni <pabeni@...hat.com>,
        "netfilter-devel@...r.kernel.org" <netfilter-devel@...r.kernel.org>,
        "coreteam@...filter.org" <coreteam@...filter.org>,
        "netdev@...r.kernel.org" <netdev@...r.kernel.org>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
        "lvc-project@...uxtesting.org" <lvc-project@...uxtesting.org>
Subject: 


Date: Tue, 20 Dec 2022 15:29:23 +0300
Subject: [PATCH] netfilter: ipset: Fix overflow before widen in the
 bitmap_ip_create() function.@@

When first_ip is 0, last_ip is 0xFFFFFFF, and netmask is 31, the value of
an arithmetic expression 2 << (netmask - mask_bits - 1) is subject
to overflow due to a failure casting operands to a larger data type
before performing the arithmetic.

Note that it's harmless since the value will be checked at the next step.

Found by InfoTeCS on behalf of Linux Verification Center
(linuxtesting.org) with SVACE.

Fixes: b9fed748185a ("netfilter: ipset: Check and reject crazy /0 input parameters")
Signed-off-by: Ilia.Gavrilov <Ilia.Gavrilov@...otecs.ru>
---
 net/netfilter/ipset/ip_set_bitmap_ip.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/net/netfilter/ipset/ip_set_bitmap_ip.c b/net/netfilter/ipset/ip_set_bitmap_ip.c
index a8ce04a4bb72..b8f0fb37378f 100644
--- a/net/netfilter/ipset/ip_set_bitmap_ip.c
+++ b/net/netfilter/ipset/ip_set_bitmap_ip.c
@@ -309,7 +309,7 @@ bitmap_ip_create(struct net *net, struct ip_set *set, struct nlattr *tb[],

 pr_debug("mask_bits %u, netmask %u\n", mask_bits, netmask);
 hosts = 2 << (32 - netmask - 1);
-elements = 2 << (netmask - mask_bits - 1);
+elements = 2UL << (netmask - mask_bits - 1);
 }
 if (elements > IPSET_BITMAP_MAX_RANGE + 1)
 return -IPSET_ERR_BITMAP_RANGE_SIZE;
--
2.30.2


С уважением,
Илья Гаврилов
Ведущий программист
Отдел разработки
АО "ИнфоТеКС" в г. Санкт-Петербург
127287, г. Москва, Старый Петровско-Разумовский проезд, дом 1/23, стр. 1
T: +7 495 737-61-92 ( доб. 4921)
Ф: +7 495 737-72-78


Ilia.Gavrilov@...otecs.ru
www.infotecs.ru