[PATCH 4.9 2/2] moxart: fix potential use-after-free on remove path

Greg Kroah-Hartman
2022-02-09T19:26:38Z

From: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

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>
---
drivers/mmc/host/moxart-mmc.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

--- a/drivers/mmc/host/moxart-mmc.c
+++ b/drivers/mmc/host/moxart-mmc.c
@@ -698,12 +698,12 @@ static int moxart_remove(struct platform
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;
}