net: systemport: fix index check to avoid an array out of bounds access

[ Upstream commit c0368595 ]

Currently the bounds check on index is off by one and can lead to
an out of bounds access on array priv->filters_loc when index is
RXCHK_BRCM_TAG_MAX.

Fixes: bb9051a2 ("net: systemport: Add support for WAKE_FILTER")
Signed-off-by: Colin Ian King <colin.king@canonical.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/net/ethernet/broadcom/bcmsysport.c

@@ -2168,7 +2168,7 @@ static int bcm_sysport_rule_set(struct bcm_sysport_priv *priv,
 		return -ENOSPC;
 
 	index = find_first_zero_bit(priv->filters, RXCHK_BRCM_TAG_MAX);
-	if (index > RXCHK_BRCM_TAG_MAX)
+	if (index >= RXCHK_BRCM_TAG_MAX)
 		return -ENOSPC;
 
 	/* Location is the classification ID, and index is the position