Patch "ieee802154: ca8210: Fix a potential UAF in ca8210_probe" has been added to the 4.19-stable tree

[Sasha Levin <sashal@xxxxxxxxxx>]

This is a note to let you know that I've just added the patch titled

    ieee802154: ca8210: Fix a potential UAF in ca8210_probe

to the 4.19-stable tree which can be found at:
    http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
     ieee802154-ca8210-fix-a-potential-uaf-in-ca8210_prob.patch
and it can be found in the queue-4.19 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.



commit 6e2ba3cac2c255a3b957f2b8045172c199410beb
Author: Dinghao Liu <dinghao.liu@xxxxxxxxxx>
Date:   Sat Oct 7 11:30:49 2023 +0800

    ieee802154: ca8210: Fix a potential UAF in ca8210_probe
    
    [ 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>

diff --git a/drivers/net/ieee802154/ca8210.c b/drivers/net/ieee802154/ca8210.c
index f75faec23cc98..525f92e896699 100644
--- a/drivers/net/ieee802154/ca8210.c
+++ b/drivers/net/ieee802154/ca8210.c
@@ -2781,7 +2781,6 @@ 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;
@@ -2798,18 +2797,8 @@ 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);
 }
 
 /**
@@ -2821,8 +2810,8 @@ 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);