From: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Date: Thu, 27 Jan 2022 07:16:38 +0000 (+0100)
Subject: moxart: fix potential use-after-free on remove path
X-Git-Tag: v5.17-rc4~42^2
X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=bd2db32e7c3e35bd4d9b8bbff689434a50893546;p=thirdparty%2Fkernel%2Flinux.git

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 16d1c7a43d331..b6eb75f4bbfc6 100644
--- 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;
 }