diff mbox series

[net,2/3] netfilter: ipset: Fix overflow before widen in the bitmap_ip_create() function.

Message ID 20230113164106.311491-3-pablo@netfilter.org
State Accepted
Delegated to: Pablo Neira
Headers show
Series [net,1/3] selftests: netfilter: fix transaction test script timeout handling | expand

Commit Message

Pablo Neira Ayuso Jan. 13, 2023, 4:41 p.m. UTC 
From: Gavrilov Ilia <Ilia.Gavrilov@infotecs.ru>

When first_ip is 0, last_ip is 0xFFFFFFFF, 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@infotecs.ru>
Reviewed-by: Simon Horman <simon.horman@corigine.com>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
---
 net/netfilter/ipset/ip_set_bitmap_ip.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)
diff mbox series

Patch

diff --git a/net/netfilter/ipset/ip_set_bitmap_ip.c b/net/netfilter/ipset/ip_set_bitmap_ip.c
index a8ce04a4bb72..e4fa00abde6a 100644
--- a/net/netfilter/ipset/ip_set_bitmap_ip.c
+++ b/net/netfilter/ipset/ip_set_bitmap_ip.c
@@ -308,8 +308,8 @@  bitmap_ip_create(struct net *net, struct ip_set *set, struct nlattr *tb[],
 			return -IPSET_ERR_BITMAP_RANGE;
 
 		pr_debug("mask_bits %u, netmask %u\n", mask_bits, netmask);
-		hosts = 2 << (32 - netmask - 1);
-		elements = 2 << (netmask - mask_bits - 1);
+		hosts = 2U << (32 - netmask - 1);
+		elements = 2UL << (netmask - mask_bits - 1);
 	}
 	if (elements > IPSET_BITMAP_MAX_RANGE + 1)
 		return -IPSET_ERR_BITMAP_RANGE_SIZE;