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Message-ID: <20180706145422.GA29390@openwall.com> Date: Fri, 6 Jul 2018 16:54:22 +0200 From: Solar Designer <solar@...nwall.com> To: oss-security@...ts.openwall.com Cc: zrlw@...a.com Subject: Re: mmap vulnerability in motion eye video4linux driver for Sony Vaio PictureBook On Fri, Jul 06, 2018 at 03:26:55PM +0200, Greg KH wrote: > On Fri, Jul 06, 2018 at 08:35:43PM +0800, zrlw@...a.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. I think zrlw@...a.com is not subscribed, so CC'ing. I wonder if it's also possible to cause integer overflow on "(unsigned long)meye.grab_fbuffer + offset", bringing pos below meye.grab_fbuffer, and what the impact of that would be. Alexander
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