| Message ID | 20220114075934.302464-1-gregkh@linuxfoundation.org |
|---|---|
| State | New |
| Headers | show |
| Series | moxart: fix potential use-after-free on remove path | expand |
On Fri, 14 Jan 2022 at 08:59, Greg Kroah-Hartman <gregkh@linuxfoundation.org> wrote: > > 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> > --- > drivers/mmc/host/moxart-mmc.c | 9 +++++---- > 1 file changed, 5 insertions(+), 4 deletions(-) > > diff --git a/drivers/mmc/host/moxart-mmc.c b/drivers/mmc/host/moxart-mmc.c > index 16d1c7a43d33..f5d96940a9b8 100644 > --- a/drivers/mmc/host/moxart-mmc.c > +++ b/drivers/mmc/host/moxart-mmc.c > @@ -697,6 +697,7 @@ static int moxart_remove(struct platform_device *pdev) > { > struct mmc_host *mmc = dev_get_drvdata(&pdev->dev); > struct moxart_host *host = mmc_priv(mmc); > + void __iomem *base = host->base; > > dev_set_drvdata(&pdev->dev, NULL); > > @@ -707,10 +708,10 @@ static int moxart_remove(struct platform_device *pdev) > 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); Rather than doing it like this, I think it would be easier to move mmc_free_host() below this part. That's usually what mmc host drivers do clean up things in ->remove(). > + writel(0, base + REG_INTERRUPT_MASK); > + writel(0, base + REG_POWER_CONTROL); > + writel(readl(base + REG_CLOCK_CONTROL) | CLK_OFF, > + base + REG_CLOCK_CONTROL); > > return 0; > } Kind regards Uffe
On Fri, Jan 21, 2022 at 01:41:27PM +0100, Ulf Hansson wrote: > On Fri, 14 Jan 2022 at 08:59, Greg Kroah-Hartman > <gregkh@linuxfoundation.org> wrote: > > > > 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> > > --- > > drivers/mmc/host/moxart-mmc.c | 9 +++++---- > > 1 file changed, 5 insertions(+), 4 deletions(-) > > > > diff --git a/drivers/mmc/host/moxart-mmc.c b/drivers/mmc/host/moxart-mmc.c > > index 16d1c7a43d33..f5d96940a9b8 100644 > > --- a/drivers/mmc/host/moxart-mmc.c > > +++ b/drivers/mmc/host/moxart-mmc.c > > @@ -697,6 +697,7 @@ static int moxart_remove(struct platform_device *pdev) > > { > > struct mmc_host *mmc = dev_get_drvdata(&pdev->dev); > > struct moxart_host *host = mmc_priv(mmc); > > + void __iomem *base = host->base; > > > > dev_set_drvdata(&pdev->dev, NULL); > > > > @@ -707,10 +708,10 @@ static int moxart_remove(struct platform_device *pdev) > > 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); > > Rather than doing it like this, I think it would be easier to move > mmc_free_host() below this part. That's usually what mmc host drivers > do clean up things in ->remove(). > > > + writel(0, base + REG_INTERRUPT_MASK); > > + writel(0, base + REG_POWER_CONTROL); > > + writel(readl(base + REG_CLOCK_CONTROL) | CLK_OFF, > > + base + REG_CLOCK_CONTROL); > > Ok, I can do that, I didn't know if it would cause any functionality changes, so I was trying to preserve the same logic that the driver currently has. Do you have this device to test this with? thanks, greg k-h
On Fri, 21 Jan 2022 at 14:54, Greg Kroah-Hartman <gregkh@linuxfoundation.org> wrote: > > On Fri, Jan 21, 2022 at 01:41:27PM +0100, Ulf Hansson wrote: > > On Fri, 14 Jan 2022 at 08:59, Greg Kroah-Hartman > > <gregkh@linuxfoundation.org> wrote: > > > > > > 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> > > > --- > > > drivers/mmc/host/moxart-mmc.c | 9 +++++---- > > > 1 file changed, 5 insertions(+), 4 deletions(-) > > > > > > diff --git a/drivers/mmc/host/moxart-mmc.c b/drivers/mmc/host/moxart-mmc.c > > > index 16d1c7a43d33..f5d96940a9b8 100644 > > > --- a/drivers/mmc/host/moxart-mmc.c > > > +++ b/drivers/mmc/host/moxart-mmc.c > > > @@ -697,6 +697,7 @@ static int moxart_remove(struct platform_device *pdev) > > > { > > > struct mmc_host *mmc = dev_get_drvdata(&pdev->dev); > > > struct moxart_host *host = mmc_priv(mmc); > > > + void __iomem *base = host->base; > > > > > > dev_set_drvdata(&pdev->dev, NULL); > > > > > > @@ -707,10 +708,10 @@ static int moxart_remove(struct platform_device *pdev) > > > 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); > > > > Rather than doing it like this, I think it would be easier to move > > mmc_free_host() below this part. That's usually what mmc host drivers > > do clean up things in ->remove(). > > > > > + writel(0, base + REG_INTERRUPT_MASK); > > > + writel(0, base + REG_POWER_CONTROL); > > > + writel(readl(base + REG_CLOCK_CONTROL) | CLK_OFF, > > > + base + REG_CLOCK_CONTROL); > > > > > Ok, I can do that, I didn't know if it would cause any functionality > changes, so I was trying to preserve the same logic that the driver > currently has. Yes, but it's most likely just a simple mistake that was made by the original author. > > Do you have this device to test this with? No, I don't. Although, I am confident that it should work fine too. > > thanks, > > greg k-h Kind regards Uffe
On Fri, Jan 21, 2022 at 03:24:05PM +0100, Ulf Hansson wrote: > On Fri, 21 Jan 2022 at 14:54, Greg Kroah-Hartman > <gregkh@linuxfoundation.org> wrote: > > > > On Fri, Jan 21, 2022 at 01:41:27PM +0100, Ulf Hansson wrote: > > > On Fri, 14 Jan 2022 at 08:59, Greg Kroah-Hartman > > > <gregkh@linuxfoundation.org> wrote: > > > > > > > > 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> > > > > --- > > > > drivers/mmc/host/moxart-mmc.c | 9 +++++---- > > > > 1 file changed, 5 insertions(+), 4 deletions(-) > > > > > > > > diff --git a/drivers/mmc/host/moxart-mmc.c b/drivers/mmc/host/moxart-mmc.c > > > > index 16d1c7a43d33..f5d96940a9b8 100644 > > > > --- a/drivers/mmc/host/moxart-mmc.c > > > > +++ b/drivers/mmc/host/moxart-mmc.c > > > > @@ -697,6 +697,7 @@ static int moxart_remove(struct platform_device *pdev) > > > > { > > > > struct mmc_host *mmc = dev_get_drvdata(&pdev->dev); > > > > struct moxart_host *host = mmc_priv(mmc); > > > > + void __iomem *base = host->base; > > > > > > > > dev_set_drvdata(&pdev->dev, NULL); > > > > > > > > @@ -707,10 +708,10 @@ static int moxart_remove(struct platform_device *pdev) > > > > 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); > > > > > > Rather than doing it like this, I think it would be easier to move > > > mmc_free_host() below this part. That's usually what mmc host drivers > > > do clean up things in ->remove(). > > > > > > > + writel(0, base + REG_INTERRUPT_MASK); > > > > + writel(0, base + REG_POWER_CONTROL); > > > > + writel(readl(base + REG_CLOCK_CONTROL) | CLK_OFF, > > > > + base + REG_CLOCK_CONTROL); > > > > > > > > Ok, I can do that, I didn't know if it would cause any functionality > > changes, so I was trying to preserve the same logic that the driver > > currently has. > > Yes, but it's most likely just a simple mistake that was made by the > original author. > > > > > Do you have this device to test this with? > > No, I don't. > > Although, I am confident that it should work fine too. Great, now sent v2: https://lore.kernel.org/r/20220127071638.4057899-1-gregkh@linuxfoundation.org
diff --git a/drivers/mmc/host/moxart-mmc.c b/drivers/mmc/host/moxart-mmc.c index 16d1c7a43d33..f5d96940a9b8 100644 --- a/drivers/mmc/host/moxart-mmc.c +++ b/drivers/mmc/host/moxart-mmc.c @@ -697,6 +697,7 @@ static int moxart_remove(struct platform_device *pdev) { struct mmc_host *mmc = dev_get_drvdata(&pdev->dev); struct moxart_host *host = mmc_priv(mmc); + void __iomem *base = host->base; dev_set_drvdata(&pdev->dev, NULL); @@ -707,10 +708,10 @@ static int moxart_remove(struct platform_device *pdev) 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); + writel(0, base + REG_INTERRUPT_MASK); + writel(0, base + REG_POWER_CONTROL); + writel(readl(base + REG_CLOCK_CONTROL) | CLK_OFF, + base + REG_CLOCK_CONTROL); return 0; }
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> --- drivers/mmc/host/moxart-mmc.c | 9 +++++---- 1 file changed, 5 insertions(+), 4 deletions(-)