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From:   Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To:     linux-kernel@vger.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        stable@vger.kernel.org, Yi Chen <yiche@redhat.com>,
        Andrea Claudi <aclaudi@redhat.com>,
        Julian Anastasov <ja@ssi.bg>,
        Simon Horman <horms@verge.net.au>,
        Pablo Neira Ayuso <pablo@netfilter.org>,
        Sasha Levin <sashal@kernel.org>
Subject: [PATCH 4.14 46/75] ipvs: check that ip_vs_conn_tab_bits is between 8 and 20
Date:   Mon,  4 Oct 2021 14:52:21 +0200
Message-Id: <20211004125033.074210545@linuxfoundation.org>
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From: Andrea Claudi <aclaudi@redhat.com>

[ 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>
---
 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 3d2ac71a83ec..620c865c230b 100644
--- a/net/netfilter/ipvs/ip_vs_conn.c
+++ b/net/netfilter/ipvs/ip_vs_conn.c
@@ -1406,6 +1406,10 @@ 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;
 
-- 
2.33.0