[PATCH 4.14 05/66] ieee802154: ca8210: Fix a potential UAF in ca8210_probe

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4.14-stable review patch.  If anyone has any objections, please let me know.

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

From: Dinghao Liu <dinghao.liu@xxxxxxxxxx>

[ Upstream commit f990874b1c98fe8e57ee9385669f501822979258 ]

If of_clk_add_provider() fails in ca8210_register_ext_clock(),
it calls clk_unregister() to release priv->clk and returns an
error. However, the caller ca8210_probe() then calls ca8210_remove(),
where priv->clk is freed again in ca8210_unregister_ext_clock(). In
this case, a use-after-free may happen in the second time we call
clk_unregister().

Fix this by removing the first clk_unregister(). Also, priv->clk could
be an error code on failure of clk_register_fixed_rate(). Use
IS_ERR_OR_NULL to catch this case in ca8210_unregister_ext_clock().

Fixes: ded845a781a5 ("ieee802154: Add CA8210 IEEE 802.15.4 device driver")
Signed-off-by: Dinghao Liu <dinghao.liu@xxxxxxxxxx>
Message-ID: <20231007033049.22353-1-dinghao.liu@xxxxxxxxxx>
Signed-off-by: Stefan Schmidt <stefan@xxxxxxxxxxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
---
 drivers/net/ieee802154/ca8210.c | 17 +++--------------
 1 file changed, 3 insertions(+), 14 deletions(-)

diff --git a/drivers/net/ieee802154/ca8210.c b/drivers/net/ieee802154/ca8210.c
index 4ec65582eaf70..d903106436dc6 100644
--- a/drivers/net/ieee802154/ca8210.c
+++ b/drivers/net/ieee802154/ca8210.c
@@ -2782,7 +2782,6 @@ static int ca8210_register_ext_clock(struct spi_device *spi)
 	struct device_node *np = spi->dev.of_node;
 	struct ca8210_priv *priv = spi_get_drvdata(spi);
 	struct ca8210_platform_data *pdata = spi->dev.platform_data;
-	int ret = 0;
 
 	if (!np)
 		return -EFAULT;
@@ -2799,18 +2798,8 @@ static int ca8210_register_ext_clock(struct spi_device *spi)
 		dev_crit(&spi->dev, "Failed to register external clk\n");
 		return PTR_ERR(priv->clk);
 	}
-	ret = of_clk_add_provider(np, of_clk_src_simple_get, priv->clk);
-	if (ret) {
-		clk_unregister(priv->clk);
-		dev_crit(
-			&spi->dev,
-			"Failed to register external clock as clock provider\n"
-		);
-	} else {
-		dev_info(&spi->dev, "External clock set as clock provider\n");
-	}
 
-	return ret;
+	return of_clk_add_provider(np, of_clk_src_simple_get, priv->clk);
 }
 
 /**
@@ -2822,8 +2811,8 @@ static void ca8210_unregister_ext_clock(struct spi_device *spi)
 {
 	struct ca8210_priv *priv = spi_get_drvdata(spi);
 
-	if (!priv->clk)
-		return
+	if (IS_ERR_OR_NULL(priv->clk))
+		return;
 
 	of_clk_del_provider(spi->dev.of_node);
 	clk_unregister(priv->clk);
-- 
2.40.1






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