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@zju.edu.cn ---

Changelog:

v2: -Remove the first clk_unregister() instead of nulling priv->clk.

v3: -Simplify ca8210_register_ext_clock(). -Add a ';' after return in ca8210_unregister_ext_clock().

v4: -Remove an unused variable 'ret'. --- 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 aebb19f1b3a4..4ec0dab38872 100644 --- a/drivers/net/ieee802154/ca8210.c +++ b/drivers/net/ieee802154/ca8210.c @@ -2740,7 +2740,6 @@ 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; @@ -2757,18 +2756,8 @@ 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); }

/** @@ -2780,8 +2769,8 @@ 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);