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From:   Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To:     linux-kernel@vger.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        stable@vger.kernel.org, Florian Fainelli <f.fainelli@gmail.com>,
        "David S. Miller" <davem@davemloft.net>
Subject: [PATCH 4.16 014/161] net: dsa: bcm_sf2: Fix RX_CLS_LOC_ANY overwrite for last rule
Date:   Thu, 24 May 2018 11:37:19 +0200
Message-Id: <20180524093020.106555710@linuxfoundation.org>
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4.16-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Florian Fainelli <f.fainelli@gmail.com>

[ Upstream commit 43a5e00f38fe8933a1c716bfe5b30e97f749d94b ]

When we let the kernel pick up a rule location with RX_CLS_LOC_ANY, we
would be able to overwrite the last rules because of a number of issues.

The IPv4 code path would not be checking that rule_index is within
bounds, and it would also only be allowed to pick up rules from range
0..126 instead of the full 0..127 range. This would lead us to allow
overwriting the last rule when we let the kernel pick-up the location.

Fixes: 3306145866b6 ("net: dsa: bcm_sf2: Move IPv4 CFP processing to specific functions")
Signed-off-by: Florian Fainelli <f.fainelli@gmail.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 |    5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

--- a/drivers/net/dsa/bcm_sf2_cfp.c
+++ b/drivers/net/dsa/bcm_sf2_cfp.c
@@ -354,10 +354,13 @@ static int bcm_sf2_cfp_ipv4_rule_set(str
 	/* Locate the first rule available */
 	if (fs->location == RX_CLS_LOC_ANY)
 		rule_index = find_first_zero_bit(priv->cfp.used,
-						 bcm_sf2_cfp_rule_size(priv));
+						 priv->num_cfp_rules);
 	else
 		rule_index = fs->location;
 
+	if (rule_index > bcm_sf2_cfp_rule_size(priv))
+		return -ENOSPC;
+
 	layout = &udf_tcpip4_layout;
 	/* We only use one UDF slice for now */
 	slice_num = bcm_sf2_get_slice_number(layout, 0);