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From 473c59ab5de5acaf5325ca4c5fc10f24064f5eb4 Mon Sep 17 00:00:00 2001
From: Andrea Claudi <aclaudi@redhat.com>
Date: Fri, 10 Sep 2021 18:08:39 +0200
Subject: [PATCH] ipvs: check that ip_vs_conn_tab_bits is between 8 and 20
Git-commit: 69e73dbfda14fbfe748d3812da1244cce2928dcb
Patch-mainline: v5.15-rc4
References: stable-5.14.10

[ Upstream commit 69e73dbfda14fbfe748d3812da1244cce2928dcb ]

ip_vs_conn_tab_bits may be provided by the user through the
conn_tab_bits module parameter. If this value is greater than 31, or
less than 0, the shift operator used to derive tab_size causes undefined
behaviour.

Fix this checking ip_vs_conn_tab_bits value to be in the range specified
in ipvs Kconfig. If not, simply use default value.

Fixes: 6f7edb4881bf ("IPVS: Allow boot time change of hash size")
Reported-by: Yi Chen <yiche@redhat.com>
Signed-off-by: Andrea Claudi <aclaudi@redhat.com>
Acked-by: Julian Anastasov <ja@ssi.bg>
Acked-by: Simon Horman <horms@verge.net.au>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
Acked-by: Takashi Iwai <tiwai@suse.de>

---
 net/netfilter/ipvs/ip_vs_conn.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/net/netfilter/ipvs/ip_vs_conn.c b/net/netfilter/ipvs/ip_vs_conn.c
index c100c6b112c8..2c467c422dc6 100644
--- a/net/netfilter/ipvs/ip_vs_conn.c
+++ b/net/netfilter/ipvs/ip_vs_conn.c
@@ -1468,6 +1468,10 @@ int __init ip_vs_conn_init(void)
 	int idx;
 
 	/* Compute size and mask */
+	if (ip_vs_conn_tab_bits < 8 || ip_vs_conn_tab_bits > 20) {
+		pr_info("conn_tab_bits not in [8, 20]. Using default value\n");
+		ip_vs_conn_tab_bits = CONFIG_IP_VS_TAB_BITS;
+	}
 	ip_vs_conn_tab_size = 1 << ip_vs_conn_tab_bits;
 	ip_vs_conn_tab_mask = ip_vs_conn_tab_size - 1;
 
-- 
2.26.2