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From:   Oleksij Rempel <o.rempel@pengutronix.de>
To:     "David S. Miller" <davem@davemloft.net>,
        Andrew Lunn <andrew@lunn.ch>,
        Eric Dumazet <edumazet@google.com>,
        Florian Fainelli <f.fainelli@gmail.com>,
        Jakub Kicinski <kuba@kernel.org>,
        Paolo Abeni <pabeni@redhat.com>,
        Vladimir Oltean <olteanv@gmail.com>,
        Woojung Huh <woojung.huh@microchip.com>,
        Arun Ramadoss <arun.ramadoss@microchip.com>,
        "Russell King (Oracle)" <linux@armlinux.org.uk>
Cc:     Oleksij Rempel <o.rempel@pengutronix.de>,
        Dan Carpenter <dan.carpenter@linaro.org>,
        kernel@pengutronix.de, linux-kernel@vger.kernel.org,
        netdev@vger.kernel.org, UNGLinuxDriver@microchip.com,
        Petr Machata <petrm@nvidia.com>,
        Lukasz Majewski <lukma@denx.de>
Subject: [PATCH net-next v1 1/1] net: dsa: microchip: Fix uninitialized var in ksz9477_acl_move_entries()
Date:   Fri,  6 Oct 2023 13:58:22 +0200
Message-Id: <20231006115822.144152-1-o.rempel@pengutronix.de>
MIME-Version: 1.0
Content-Transfer-Encoding: 8bit
Precedence: bulk

Address an issue in ksz9477_acl_move_entries() where, in the scenario
(src_idx == dst_idx), ksz9477_validate_and_get_src_count() returns 0,
leading to usage of uninitialized src_count and dst_count variables,
which causes undesired behavior as it attempts to move ACL entries
around.

Fixes: 002841be134e ("net: dsa: microchip: Add partial ACL support for ksz9477 switches")
Reported-by: Dan Carpenter <dan.carpenter@linaro.org>
Suggested-by: Vladimir Oltean <olteanv@gmail.com>
Signed-off-by: Oleksij Rempel <o.rempel@pengutronix.de>
---
 drivers/net/dsa/microchip/ksz9477_acl.c | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/drivers/net/dsa/microchip/ksz9477_acl.c b/drivers/net/dsa/microchip/ksz9477_acl.c
index 06d74c19eb94..7ba778df63ac 100644
--- a/drivers/net/dsa/microchip/ksz9477_acl.c
+++ b/drivers/net/dsa/microchip/ksz9477_acl.c
@@ -420,10 +420,6 @@ static int ksz9477_validate_and_get_src_count(struct ksz_device *dev, int port,
 		return -EINVAL;
 	}
 
-	/* Nothing to do */
-	if (src_idx == dst_idx)
-		return 0;
-
 	/* Validate if the source entries are contiguous */
 	ret = ksz9477_acl_get_cont_entr(dev, port, src_idx);
 	if (ret < 0)
@@ -556,6 +552,10 @@ static int ksz9477_acl_move_entries(struct ksz_device *dev, int port,
 	struct ksz9477_acl_entries *acles = &acl->acles;
 	int src_count, ret, dst_count;
 
+	/* Nothing to do */
+	if (src_idx == dst_idx)
+		return 0;
+
 	ret = ksz9477_validate_and_get_src_count(dev, port, src_idx, dst_idx,
 						 &src_count, &dst_count);
 	if (ret)
-- 
2.39.2