net: dsa: bcm_sf2: fix buffer overflow doing set_rxnfc

BugLink: https://bugs.launchpad.net/bugs/1838459
[ 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>
Signed-off-by: Kamal Mostafa <kamal@canonical.com>
Signed-off-by: Khalid Elmously <khalid.elmously@canonical.com>

diff --git a/drivers/net/dsa/bcm_sf2_cfp.c b/drivers/net/dsa/bcm_sf2_cfp.c
index b89acaee12d4364247a694ad989d2ae06ca640aa..50842c9e7820c1b247e9e15dc497c62f0312f53c 100644 (file)
--- a/drivers/net/dsa/bcm_sf2_cfp.c
+++ b/drivers/net/dsa/bcm_sf2_cfp.c
@@ -740,6 +740,9 @@ static int bcm_sf2_cfp_rule_set(struct dsa_switch *ds, int port,
             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;
@@ -827,6 +830,9 @@ static int bcm_sf2_cfp_rule_del(struct bcm_sf2_priv *priv, int port,
        u32 next_loc = 0;
        int ret;
 
+       if (loc >= CFP_NUM_RULES)
+               return -EINVAL;
+
        /* Refuse deleting unused rules, and those that are not unique since
         * that could leave IPv6 rules with one of the chained rule in the
         * table.