[PATCH 4.14 11/75] net: dsa: bcm_sf2: fix buffer overflow doing set_rxnfc

[Greg Kroah-Hartman <gregkh@linuxfoundation.org>]

From: Dan Carpenter <dan.carpenter@oracle.com>

[ Upstream commit f949a12fd697479f68d99dc65e9bbab68ee49043 ]

The "fs->location" is a u32 that comes from the user in ethtool_set_rxnfc().
We can't pass unclamped values to test_bit() or it results in an out of
bounds access beyond the end of the bitmap.

Fixes: 7318166cacad ("net: dsa: bcm_sf2: Add support for ethtool::rxnfc")
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
 drivers/net/dsa/bcm_sf2_cfp.c |    6 ++++++
 1 file changed, 6 insertions(+)

--- a/drivers/net/dsa/bcm_sf2_cfp.c
+++ b/drivers/net/dsa/bcm_sf2_cfp.c
@@ -130,6 +130,9 @@ static int bcm_sf2_cfp_rule_set(struct d
 	    (fs->m_ext.vlan_etype || fs->m_ext.data[1]))
 		return -EINVAL;
 
+	if (fs->location != RX_CLS_LOC_ANY && fs->location >= CFP_NUM_RULES)
+		return -EINVAL;
+
 	if (fs->location != RX_CLS_LOC_ANY &&
 	    test_bit(fs->location, priv->cfp.used))
 		return -EBUSY;
@@ -330,6 +333,9 @@ static int bcm_sf2_cfp_rule_del(struct b
 	int ret;
 	u32 reg;
 
+	if (loc >= CFP_NUM_RULES)
+		return -EINVAL;
+
 	/* Refuse deletion of unused rules, and the default reserved rule */
 	if (!test_bit(loc, priv->cfp.used) || loc == 0)
 		return -EINVAL;