From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751682AbdJTMcN (ORCPT ); Fri, 20 Oct 2017 08:32:13 -0400 Received: from terminus.zytor.com ([65.50.211.136]:59097 "EHLO terminus.zytor.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751410AbdJTMcK (ORCPT ); Fri, 20 Oct 2017 08:32:10 -0400 Date: Fri, 20 Oct 2017 05:25:19 -0700 From: tip-bot for Craig Bergstrom Message-ID: Cc: hpa@zytor.com, toshi.kani@hp.com, mcgrof@suse.com, linux-kernel@vger.kernel.org, torvalds@linux-foundation.org, craigb@google.com, brgerst@gmail.com, peterz@infradead.org, tglx@linutronix.de, dvlasenk@redhat.com, bp@alien8.de, jpoimboe@redhat.com, luto@kernel.org, mingo@kernel.org, akpm@linux-foundation.org Reply-To: akpm@linux-foundation.org, mingo@kernel.org, luto@kernel.org, jpoimboe@redhat.com, bp@alien8.de, dvlasenk@redhat.com, tglx@linutronix.de, brgerst@gmail.com, peterz@infradead.org, craigb@google.com, mcgrof@suse.com, linux-kernel@vger.kernel.org, torvalds@linux-foundation.org, toshi.kani@hp.com, hpa@zytor.com In-Reply-To: <20171019192856.39672-1-craigb@google.com> References: <20171019192856.39672-1-craigb@google.com> To: linux-tip-commits@vger.kernel.org Subject: [tip:x86/mm] x86/mm: Limit mmap() of /dev/mem to valid physical addresses Git-Commit-ID: ce56a86e2ade45d052b3228cdfebe913a1ae7381 X-Mailer: tip-git-log-daemon Robot-ID: Robot-Unsubscribe: Contact to get blacklisted from these emails MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Content-Type: text/plain; charset=UTF-8 Content-Disposition: inline Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Commit-ID: ce56a86e2ade45d052b3228cdfebe913a1ae7381 Gitweb: https://git.kernel.org/tip/ce56a86e2ade45d052b3228cdfebe913a1ae7381 Author: Craig Bergstrom AuthorDate: Thu, 19 Oct 2017 13:28:56 -0600 Committer: Ingo Molnar CommitDate: Fri, 20 Oct 2017 09:48:00 +0200 x86/mm: Limit mmap() of /dev/mem to valid physical addresses Currently, it is possible to mmap() any offset from /dev/mem. If a program mmaps() /dev/mem offsets outside of the addressable limits of a system, the page table can be corrupted by setting reserved bits. For example if you mmap() offset 0x0001000000000000 of /dev/mem on an x86_64 system with a 48-bit bus, the page fault handler will be called with error_code set to RSVD. The kernel then crashes with a page table corruption error. This change prevents this page table corruption on x86 by refusing to mmap offsets higher than the highest valid address in the system. Signed-off-by: Craig Bergstrom Cc: Andrew Morton Cc: Andy Lutomirski Cc: Borislav Petkov Cc: Brian Gerst Cc: Denys Vlasenko Cc: H. Peter Anvin Cc: Josh Poimboeuf Cc: Linus Torvalds Cc: Luis R. Rodriguez Cc: Peter Zijlstra Cc: Thomas Gleixner Cc: Toshi Kani Cc: dsafonov@virtuozzo.com Cc: kirill.shutemov@linux.intel.com Cc: mhocko@suse.com Cc: oleg@redhat.com Link: http://lkml.kernel.org/r/20171019192856.39672-1-craigb@google.com Signed-off-by: Ingo Molnar --- arch/x86/include/asm/io.h | 4 ++++ arch/x86/mm/mmap.c | 12 ++++++++++++ 2 files changed, 16 insertions(+) diff --git a/arch/x86/include/asm/io.h b/arch/x86/include/asm/io.h index c40a95c..322d25a 100644 --- a/arch/x86/include/asm/io.h +++ b/arch/x86/include/asm/io.h @@ -110,6 +110,10 @@ build_mmio_write(__writeq, "q", unsigned long, "r", ) #endif +#define ARCH_HAS_VALID_PHYS_ADDR_RANGE +extern int valid_phys_addr_range(phys_addr_t addr, size_t size); +extern int valid_mmap_phys_addr_range(unsigned long pfn, size_t size); + /** * virt_to_phys - map virtual addresses to physical * @address: address to remap diff --git a/arch/x86/mm/mmap.c b/arch/x86/mm/mmap.c index a996798..320c623 100644 --- a/arch/x86/mm/mmap.c +++ b/arch/x86/mm/mmap.c @@ -174,3 +174,15 @@ const char *arch_vma_name(struct vm_area_struct *vma) return "[mpx]"; return NULL; } + +int valid_phys_addr_range(phys_addr_t addr, size_t count) +{ + return addr + count <= __pa(high_memory); +} + +int valid_mmap_phys_addr_range(unsigned long pfn, size_t count) +{ + phys_addr_t addr = (phys_addr_t)pfn << PAGE_SHIFT; + + return valid_phys_addr_range(addr, count); +}