From mboxrd@z Thu Jan 1 00:00:00 1970 From: baruch@tkos.co.il (Baruch Siach) Date: Thu, 9 Nov 2017 11:49:20 +0200 Subject: [PATCH 0/2] STRICT_KERNEL_RWX weakened on ARM by CONFIG_ARM_LPAE=y In-Reply-To: <20171109093734.GB12318@n2100.armlinux.org.uk> References: <20171109004144.2246-1-philip@cog.systems> <20171109093734.GB12318@n2100.armlinux.org.uk> Message-ID: <20171109094920.2xpyhtrwj5kjb2qz@tarshish> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org Hi Russell, On Thu, Nov 09, 2017 at 09:37:34AM +0000, Russell King - ARM Linux wrote: > On Wed, Nov 08, 2017 at 05:23:43PM -0800, Kees Cook wrote: > > On Wed, Nov 8, 2017 at 4:41 PM, Philip Derrin wrote: > > > Hi, > > > > > > This patch series fixes a bug which makes CONFIG_STRICT_KERNEL_RWX ineffective > > > when CONFIG_ARM_LPAE is enabled. Specifically, the kernel text and rodata are > > > mapped writeable. This has been the case since DEBUG_RODATA for ARM was first > > > merged in 3.19. > > > > > > The cause was an incorrect conflict resolution in 1e3479225acb ("ARM: 8275/1: > > > mm: fix PMD_SECT_RDONLY undeclared compile error") between the commit that > > > implemented DEBUG_RODATA, 80d6b0c2eed2 ("ARM: mm: allow text and rodata > > > sections to be read-only"), and another that moved the LPAE read-only bit into > > > a software bit, ded947798469 ("ARM: 8109/1: mm: Modify pte_write and pmd_write > > > logic for LPAE"). > > > > > > The incorrect mappings were not apparent in the debugfs kernel_page_tables > > > dump because that was checking only the software RO bit, not the hardware RO > > > bit. > > > > Thanks for catching this! Please consider both patches: > > > > Reviewed-by: Kees Cook > > Where are these patches, and why weren't they copied to the arm kernel > list? I got the patches from the list. Cover: http://lists.infradead.org/pipermail/linux-arm-kernel/2017-November/541532.html 1/2: http://lists.infradead.org/pipermail/linux-arm-kernel/2017-November/541531.html 2/2: http://lists.infradead.org/pipermail/linux-arm-kernel/2017-November/541533.html baruch -- http://baruch.siach.name/blog/ ~. .~ Tk Open Systems =}------------------------------------------------ooO--U--Ooo------------{= - baruch at tkos.co.il - tel: +972.52.368.4656, http://www.tkos.co.il -