Re: [PATCH] vgaarb: fix typo deference when copying from userspace

Re: [PATCH] vgaarb: fix typo deference when copying from userspace

[Helge Deller]

On 01/12/2010 06:58 PM, Tiago Vignatti wrote:
> From: Brad Spengler<spender@grsecurity.net>
>
> libpciaccess is not triggering such code though.
>
> Signed-off-by: Tiago Vignatti<tiago.vignatti@nokia.com>

I can confirm, that this patch is needed to prevent a kernel
segfault with 2.6.33-rc3  on the parisc/hppa architecture.

Tested-by: Helge Deller <deller@gmx.de>

> ---
> Andy Getzendanner tried to fix this, but he seems did a wrong approach:
> http://marc.info/?l=linux-kernel&m=126112173704466
>
> Andy: please test (and put your tag review!) this one instead. Thanks.
>
>   drivers/gpu/vga/vgaarb.c |    2 +-
>   1 files changed, 1 insertions(+), 1 deletions(-)
>
> diff --git a/drivers/gpu/vga/vgaarb.c b/drivers/gpu/vga/vgaarb.c
> index 1ac0c93..2f6cf69 100644
> --- a/drivers/gpu/vga/vgaarb.c
> +++ b/drivers/gpu/vga/vgaarb.c
> @@ -961,7 +961,7 @@ static ssize_t vga_arb_write(struct file *file, const char __user * buf,
>   		remaining -= 7;
>   		pr_devel("client 0x%p called 'target'\n", priv);
>   		/* if target is default */
> -		if (!strncmp(buf, "default", 7))
> +		if (!strncmp(curr_pos, "default", 7))
>   			pdev = pci_dev_get(vga_default_device());
>   		else {
>   			if (!vga_pci_str_to_vars(curr_pos, remaining,