moxart: fix potential use-after-free on remove path

commit bd2db32e7c3e35bd4d9b8bbff689434a50893546 upstream.

It was reported that the mmc host structure could be accessed after it
was freed in moxart_remove(), so fix this by saving the base register of
the device and using it instead of the pointer dereference.

Cc: Ulf Hansson <ulf.hansson@linaro.org>
Cc: Xiyu Yang <xiyuyang19@fudan.edu.cn>
Cc: Xin Xiong <xiongx18@fudan.edu.cn>
Cc: Xin Tan <tanxin.ctf@gmail.com>
Cc: Tony Lindgren <tony@atomide.com>
Cc: Yang Li <yang.lee@linux.alibaba.com>
Cc: linux-mmc@vger.kernel.org
Cc: stable <stable@vger.kernel.org>
Reported-by: whitehat002 <hackyzh002@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Link: https://lore.kernel.org/r/20220127071638.4057899-1-gregkh@linuxfoundation.org
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/mmc/host/moxart-mmc.c b/drivers/mmc/host/moxart-mmc.c
index 5553a5643f40560a5b3e56d8b605a93ba2e199a9..5c81dc7371db76927feb078220981874dc5bb7b9 100644 (file)
--- a/drivers/mmc/host/moxart-mmc.c
+++ b/drivers/mmc/host/moxart-mmc.c
@@ -696,12 +696,12 @@ static int moxart_remove(struct platform_device *pdev)
                if (!IS_ERR(host->dma_chan_rx))
                        dma_release_channel(host->dma_chan_rx);
                mmc_remove_host(mmc);
-               mmc_free_host(mmc);
 
                writel(0, host->base + REG_INTERRUPT_MASK);
                writel(0, host->base + REG_POWER_CONTROL);
                writel(readl(host->base + REG_CLOCK_CONTROL) | CLK_OFF,
                       host->base + REG_CLOCK_CONTROL);
+               mmc_free_host(mmc);
        }
        return 0;
 }