Re: mmap vulnerability in motion eye video4linux driver for Sony Vaio PictureBook

[Greg KH <greg () kroah com>]

On Fri, Jul 06, 2018 at 08:35:43PM +0800, zrlw () sina com wrote:
> Hi all,i found a vulnerability in motion eye video4linux driver for Sony Vaio PictureBook,it desn't validate 
> user-controlled parameter 'vma->vm_pgoff', a malicious process might access all of kernel memory from user space by 
> trying pass different arbitrary address.
> /usr/src/linux-4.4.21-69/drivers/media/pci/meye/meye.c:
> static int meye_mmap(struct file *file, struct vm_area_struct *vma)
> ...        unsigned long offset = vma->vm_pgoff << PAGE_SHIFT;
> ...        pos = (unsigned long)meye.grab_fbuffer + offset;
>         while (size > 0) {
>                 page = vmalloc_to_pfn((void *)pos);
>                 if (remap_pfn_range(vma, start, page, PAGE_SIZE, PAGE_SHARED)) {...

Commit:
        be83bbf80682 ("mmap: introduce sane default mmap limits")
which was backported to all stable kernels, should have resolved this
problem, correct?

If not, please notify the media driver maintainers and they will be glad
to fix the problem.

thanks,

greg k-h