[PATCH 5.4 13/56] ipvs: check that ip_vs_conn_tab_bits is between 8 and 20

[Greg Kroah-Hartman]

From: Andrea Claudi <aclaudi@xxxxxxxxxx>

[ 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@xxxxxxxxxx>
Signed-off-by: Andrea Claudi <aclaudi@xxxxxxxxxx>
Acked-by: Julian Anastasov <ja@xxxxxx>
Acked-by: Simon Horman <horms@xxxxxxxxxxxx>
Signed-off-by: Pablo Neira Ayuso <pablo@xxxxxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
---
 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 02f2f636798d..d1524ca4b90e 100644
--- a/net/netfilter/ipvs/ip_vs_conn.c
+++ b/net/netfilter/ipvs/ip_vs_conn.c
@@ -1394,6 +1394,10 @@ 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