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

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>

diff --git a/drivers/mmc/host/moxart-mmc.c b/drivers/mmc/host/moxart-mmc.c
index 16d1c7a43d331938e2c8fb0513eede9129776a69..b6eb75f4bbfc6d1be06dc9556d7e1cf02ac88bb6 100644 (file)
--- a/drivers/mmc/host/moxart-mmc.c
+++ b/drivers/mmc/host/moxart-mmc.c
@@ -705,12 +705,12 @@ static int moxart_remove(struct platform_device *pdev)
        if (!IS_ERR_OR_NULL(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;
 }