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* [PATCH -next] vfio: platform: reset: add missing iounmap() on error in vfio_platform_amdxgbe_reset()
@ 2021-05-13  5:09 Yang Yingliang
  2021-05-18 21:46 ` Alex Williamson
  0 siblings, 1 reply; 2+ messages in thread
From: Yang Yingliang @ 2021-05-13  5:09 UTC (permalink / raw)
  To: linux-kernel, kvm; +Cc: eric.auger, alex.williamson

Add the missing iounmap() before return from vfio_platform_amdxgbe_reset()
in the error handling case.

Fixes: 0990822c9866 ("VFIO: platform: reset: AMD xgbe reset module")
Reported-by: Hulk Robot <hulkci@huawei.com>
Signed-off-by: Yang Yingliang <yangyingliang@huawei.com>
---
 drivers/vfio/platform/reset/vfio_platform_amdxgbe.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/drivers/vfio/platform/reset/vfio_platform_amdxgbe.c b/drivers/vfio/platform/reset/vfio_platform_amdxgbe.c
index abdca900802d..c6d823a27bd6 100644
--- a/drivers/vfio/platform/reset/vfio_platform_amdxgbe.c
+++ b/drivers/vfio/platform/reset/vfio_platform_amdxgbe.c
@@ -61,8 +61,10 @@ static int vfio_platform_amdxgbe_reset(struct vfio_platform_device *vdev)
 	if (!xpcs_regs->ioaddr) {
 		xpcs_regs->ioaddr =
 			ioremap(xpcs_regs->addr, xpcs_regs->size);
-		if (!xpcs_regs->ioaddr)
+		if (!xpcs_regs->ioaddr) {
+			iounmap(xgmac_regs->ioaddr);
 			return -ENOMEM;
+		}
 	}
 
 	/* reset the PHY through MDIO*/
-- 
2.25.1


^ permalink raw reply related	[flat|nested] 2+ messages in thread

* Re: [PATCH -next] vfio: platform: reset: add missing iounmap() on error in vfio_platform_amdxgbe_reset()
  2021-05-13  5:09 [PATCH -next] vfio: platform: reset: add missing iounmap() on error in vfio_platform_amdxgbe_reset() Yang Yingliang
@ 2021-05-18 21:46 ` Alex Williamson
  0 siblings, 0 replies; 2+ messages in thread
From: Alex Williamson @ 2021-05-18 21:46 UTC (permalink / raw)
  To: Yang Yingliang; +Cc: linux-kernel, kvm, eric.auger

On Thu, 13 May 2021 13:09:24 +0800
Yang Yingliang <yangyingliang@huawei.com> wrote:

> Add the missing iounmap() before return from vfio_platform_amdxgbe_reset()
> in the error handling case.
> 
> Fixes: 0990822c9866 ("VFIO: platform: reset: AMD xgbe reset module")
> Reported-by: Hulk Robot <hulkci@huawei.com>
> Signed-off-by: Yang Yingliang <yangyingliang@huawei.com>
> ---
>  drivers/vfio/platform/reset/vfio_platform_amdxgbe.c | 4 +++-
>  1 file changed, 3 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/vfio/platform/reset/vfio_platform_amdxgbe.c b/drivers/vfio/platform/reset/vfio_platform_amdxgbe.c
> index abdca900802d..c6d823a27bd6 100644
> --- a/drivers/vfio/platform/reset/vfio_platform_amdxgbe.c
> +++ b/drivers/vfio/platform/reset/vfio_platform_amdxgbe.c
> @@ -61,8 +61,10 @@ static int vfio_platform_amdxgbe_reset(struct vfio_platform_device *vdev)
>  	if (!xpcs_regs->ioaddr) {
>  		xpcs_regs->ioaddr =
>  			ioremap(xpcs_regs->addr, xpcs_regs->size);
> -		if (!xpcs_regs->ioaddr)
> +		if (!xpcs_regs->ioaddr) {
> +			iounmap(xgmac_regs->ioaddr);
>  			return -ENOMEM;
> +		}
>  	}
>  
>  	/* reset the PHY through MDIO*/

This actually introduces multiple bugs.  vfio-platform has common code
for calling iounmap when the device is released and the struct
vfio_platform_region ioaddr member is re-used throughout the code.
Performing an iounmap() without setting the value to NULL essentially
introduces use-after-free and double free bugs.  There's no bug in the
original afaict, the iounmap occurs lazily on release.  Thanks,

Alex


^ permalink raw reply	[flat|nested] 2+ messages in thread

end of thread, other threads:[~2021-05-18 21:47 UTC | newest]

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2021-05-13  5:09 [PATCH -next] vfio: platform: reset: add missing iounmap() on error in vfio_platform_amdxgbe_reset() Yang Yingliang
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