Re: UAF in moxart_remove

[Greg KH <greg@kroah.com>]

On Tue, Jan 11, 2022 at 09:35:11AM +0100, Marcus Meissner wrote:
> Hi whitehat002,
> 
> SUSE currently does not build the moxart driver, let me defer you to
> security@kernel.org and the MMC maintainers.
> 
> i also opened a bug in our bugzilla just for tracking
> https://bugzilla.suse.com/show_bug.cgi?id=1194516
> 
> Ciao, Marcus
> On Tue, Jan 11, 2022 at 02:30:32PM +0800, whitehat002 whitehat002 wrote:
> > Hello suse security team,
> > 
> > There is a UAF in drivers/mmc/host/moxart-mmc.c
> > This is similar with
> > https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=42933c8aa14be1caa9eda41f65cde8a3a95d3e39
> > 
> > 
> > 
> > static int moxart_remove(struct platform_device *pdev)
> > {
> > struct mmc_host *mmc = dev_get_drvdata(&pdev->dev);
> > struct moxart_host *host = mmc_priv(mmc);
> > 
> > dev_set_drvdata(&pdev->dev, NULL);
> > 
> > if (!IS_ERR_OR_NULL(host->dma_chan_tx))
> > dma_release_channel(host->dma_chan_tx);
> > if (!IS_ERR_OR_NULL(host->dma_chan_rx))
> > dma_release_channel(host->dma_chan_rx);
> > mmc_remove_host(mmc);
> > mmc_free_host(mmc);   //[0] free
> > 
> > writel(0, host->base + REG_INTERRUPT_MASK); //[1] host is private data from
> > mmc_host UAF
> > writel(0, host->base + REG_POWER_CONTROL);
> > writel(readl(host->base + REG_CLOCK_CONTROL) | CLK_OFF,
> >        host->base + REG_CLOCK_CONTROL);
> > 
> > return 0;
> > }
> > 

Can you write a patch to fix this so that you can get proper credit for
fixing it as well as finding it?

thanks,

greg k-h