Hi Dinghao,
dinghao.liu@xxxxxxxxxx wrote on Mon, 25 Sep 2023 15:24:22 +0800:
> 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 nulling priv->clk after the first clk_unregister(). Also
> refine the pointer checking in ca8210_unregister_ext_clock().
>
> Fixes: ded845a781a5 ("ieee802154: Add CA8210 IEEE 802.15.4 device driver")
> Signed-off-by: Dinghao Liu <dinghao.liu@xxxxxxxxxx>
> ---
> drivers/net/ieee802154/ca8210.c | 3 ++-
> 1 file changed, 2 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/net/ieee802154/ca8210.c b/drivers/net/ieee802154/ca8210.c
> index aebb19f1b3a4..1d545879c000 100644
> --- a/drivers/net/ieee802154/ca8210.c
> +++ b/drivers/net/ieee802154/ca8210.c
> @@ -2760,6 +2760,7 @@ static int ca8210_register_ext_clock(struct spi_device *spi)
> ret = of_clk_add_provider(np, of_clk_src_simple_get, priv->clk);
> if (ret) {
> clk_unregister(priv->clk);
> + priv->clk = NULL;
This function is a bit convoluted. You could just return the result of
of_clk_add_provider() (keep the printk's if you want, they don't seem
very useful) and let ca8210_unregister_ext_clock() do the cleanup.
> dev_crit(
> &spi->dev,
> "Failed to register external clock as clock provider\n"
> @@ -2780,7 +2781,7 @@ static void ca8210_unregister_ext_clock(struct spi_device *spi)
> {
> struct ca8210_priv *priv = spi_get_drvdata(spi);
>
> - if (!priv->clk)
> + if (IS_ERR_OR_NULL(priv->clk))
Does not look useful as you are enforcing priv->clock to be valid or
NULL, it cannot be an error code.
Thanks,
Miquèl
