From mboxrd@z Thu Jan 1 00:00:00 1970 From: danielmicay@gmail.com (Daniel Micay) Date: Wed, 10 Aug 2016 13:06:34 -0400 Subject: [kernel-hardening] Re: [PATCH 2/2] arm: apply more __ro_after_init In-Reply-To: <20160810094339.GK1041@n2100.armlinux.org.uk> References: <1464979224-2085-1-git-send-email-keescook@chromium.org> <1464979224-2085-3-git-send-email-keescook@chromium.org> <20160810094339.GK1041@n2100.armlinux.org.uk> Message-ID: <1470848794.22360.1.camel@gmail.com> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org On Wed, 2016-08-10 at 10:43 +0100, Russell King - ARM Linux wrote: > On Fri, Jun 03, 2016 at 11:40:24AM -0700, Kees Cook wrote: > > > > @@ -1309,16 +1309,11 @@ void __init arm_mm_memblock_reserve(void) > > ? * Any other function or debugging method which may touch any > > device _will_ > > ? * crash the kernel. > > ? */ > > +static char vectors[PAGE_SIZE * 2] __ro_after_init > > __aligned(PAGE_SIZE); > > ?static void __init devicemaps_init(const struct machine_desc > > *mdesc) > > ?{ > > ? struct map_desc map; > > ? unsigned long addr; > > - void *vectors; > > - > > - /* > > - ?* Allocate the vector page early. > > - ?*/ > > - vectors = early_alloc(PAGE_SIZE * 2); > > This one is not appropriate.??We _do_ write to these pages after init > for FIQ handler updates.??See set_fiq_handler(). This is one of the many cases where pax_open_kernel/pax_close_kernel are needed to temporarily toggle it read-only. From grsecurity: @@ -95,7 +95,10 @@ void set_fiq_handler(void *start, unsigned int length) ? void *base = vectors_page; ? unsigned offset = FIQ_OFFSET; ? + pax_open_kernel(); ? memcpy(base + offset, start, length); + pax_close_kernel(); -------------- next part -------------- A non-text attachment was scrubbed... Name: signature.asc Type: application/pgp-signature Size: 851 bytes Desc: This is a digitally signed message part URL: