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Message-Id: <20180706160937.C94687200D7@webmail.sinamail.sina.com.cn> Date: Sat, 07 Jul 2018 00:09:37 +0800 From: <zrlw@...a.com> To: "Solar Designer" <solar@...nwall.com>, "oss-security" <oss-security@...ts.openwall.com>, Subject: Re: mmap vulnerability in motion eye video4linux driver for Sony Vaio PictureBook I sent a email to the original authors which i found in the head of meye.c, but i don't receive any response util now. I don't think commit be83bbf80682 will work on this case, this driver derived from v4l2-core which not use inode, maybe i'm wrong. ----- Original Message ----- From: Solar Designer <solar@...nwall.com> To: oss-security@...ts.openwall.com Cc: zrlw@...a.com Subject: Re: [oss-security] mmap vulnerability in motion eye video4linux driver for Sony Vaio PictureBook Date: 2018-07-06 22:54 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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