linux-kernel - Re: [PATCH] usb: gadget: amd5536udc: fix NULL pointer dereference

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <20150910180334.GA10760@psi-dev26.jf.intel.com>
Date:	Thu, 10 Sep 2015 11:03:34 -0700
From:	David Cohen <david.a.cohen@...ux.intel.com>
To:	Sudip Mukherjee <sudipm.mukherjee@...il.com>
Cc:	Thomas Dahlmann <dahlmann.thomas@...or.de>,
	Felipe Balbi <balbi@...com>,
	Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
	linux-kernel@...r.kernel.org, linux-geode@...ts.infradead.org,
	linux-usb@...r.kernel.org
Subject: Re: [PATCH] usb: gadget: amd5536udc: fix NULL pointer dereference

Hi Sudip,

On Fri, Sep 04, 2015 at 05:12:23PM +0530, Sudip Mukherjee wrote:
> We were checking if dev->regs is NULL but it was done after
> dereferencing it. Lets reset the controller and iounmap dev->regs only
> if it is not NULL.
> free_irq() does not need dev->regs, so unmaping it before freeing the
> irq should not matter.
> 
> Signed-off-by: Sudip Mukherjee <sudip@...torindia.org>
> ---
>  drivers/usb/gadget/udc/amd5536udc.c | 7 ++++---
>  1 file changed, 4 insertions(+), 3 deletions(-)
> 
> diff --git a/drivers/usb/gadget/udc/amd5536udc.c b/drivers/usb/gadget/udc/amd5536udc.c
> index fdacddb..26066d3 100644
> --- a/drivers/usb/gadget/udc/amd5536udc.c
> +++ b/drivers/usb/gadget/udc/amd5536udc.c
> @@ -3135,11 +3135,12 @@ static void udc_pci_remove(struct pci_dev *pdev)
>  	}
>  
>  	/* reset controller */
> -	writel(AMD_BIT(UDC_DEVCFG_SOFTRESET), &dev->regs->cfg);
> +	if (dev->regs) {
> +		writel(AMD_BIT(UDC_DEVCFG_SOFTRESET), &dev->regs->cfg);
> +		iounmap(dev->regs);

I'm not familiar with the driver, but you're iounmap'ing before freeing
irq. Looks fishy to me.

Br, David

> +	}
>  	if (dev->irq_registered)
>  		free_irq(pdev->irq, dev);
> -	if (dev->regs)
> -		iounmap(dev->regs);
>  	if (dev->mem_region)
>  		release_mem_region(pci_resource_start(pdev, 0),
>  				pci_resource_len(pdev, 0));
> -- 
> 1.9.1
> 
> --
> To unsubscribe from this list: send the line "unsubscribe linux-usb" in
> the body of a message to majordomo@...r.kernel.org
> More majordomo info at  http://vger.kernel.org/majordomo-info.html
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/