On Thu, 13 May 2021 13:09:24 +0800
Yang Yingliang <yangyingliang@xxxxxxxxxx> 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@xxxxxxxxxx>
> Signed-off-by: Yang Yingliang <yangyingliang@xxxxxxxxxx>
> ---
> 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
