From: Dan Carpenter <dan.carpenter@oracle.com>
Date: Wed, 6 May 2020 13:16:56 +0300
Subject: net: mvpp2: cls: Prevent buffer overflow in
 mvpp2_ethtool_cls_rule_del()
Git-commit: 722c0f00d4feea77475a5dc943b53d60824a1e4e
Patch-mainline: 5.7-rc5
References: networking-stable-20_05_12

The "info->fs.location" is a u32 that comes from the user via the
ethtool_set_rxnfc() function.  We need to check for invalid values to
prevent a buffer overflow.

I copy and pasted this check from the mvpp2_ethtool_cls_rule_ins()
function.

Fixes: 90b509b39ac9 ("net: mvpp2: cls: Add Classification offload support")
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
---
 drivers/net/ethernet/marvell/mvpp2/mvpp2_cls.c |    3 +++
 1 file changed, 3 insertions(+)

--- a/drivers/net/ethernet/marvell/mvpp2/mvpp2_cls.c
+++ b/drivers/net/ethernet/marvell/mvpp2/mvpp2_cls.c
@@ -1422,6 +1422,9 @@ int mvpp2_ethtool_cls_rule_del(struct mv
 	struct mvpp2_ethtool_fs *efs;
 	int ret;
 
+	if (info->fs.location >= MVPP2_N_RFS_ENTRIES_PER_FLOW)
+		return -EINVAL;
+
 	efs = port->rfs_rules[info->fs.location];
 	if (!efs)
 		return -EINVAL;