On Tue, May 12, 2020, at 11:04 AM, Miklos Szeredi wrote:
> > However, in this syzbot test case the 'file' is in an overlayfs filesystem
> > created as follows:
> >
> > mkdir("./file0", 000) = 0
> > mount(NULL, "./file0", "hugetlbfs", MS_MANDLOCK|MS_POSIXACL, NULL) = 0
> > chdir("./file0") = 0
> > mkdir("./file1", 000) = 0
> > mkdir("./bus", 000) = 0
> > mkdir("./file0", 000) = 0
> > mount("\177ELF\2\1\1", "./bus", "overlay", 0, "lowerdir=./bus,workdir=./file1,u"...) = 0
Is there any actual valid use case for mounting an overlayfs on top of hugetlbfs? I can't think of one. Why isn't the response to this to instead only allow mounting overlayfs on top of basically a set of whitelisted filesystems?
