On Mon, Apr 23, 2018 at 8:47 AM, Joerg Roedel <joro@xxxxxxxxxx> wrote: > From: Joerg Roedel <jroedel@xxxxxxx> > > Mapping the kernel text area to user-space makes only sense > if it has the same permissions as in the kernel page-table. > If permissions are different this will cause a TLB reload > when using the kernel page-table, which is as good as not > mapping it at all. > > On 64-bit kernels this patch makes no difference, as the > whole range cloned by pti_clone_kernel_text() is mapped RO > anyway. On 32 bit there are writeable mappings in the range, > so just keep the permissions as they are. Why are there R/W text mappings in this range? I find that to be unexpected. Shouldn't CONFIG_DEBUG_WX already complain if that were true? -Kees -- Kees Cook Pixel Security
