From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752190AbcEJIn4 (ORCPT ); Tue, 10 May 2016 04:43:56 -0400 Received: from terminus.zytor.com ([198.137.202.10]:46940 "EHLO terminus.zytor.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750989AbcEJIny (ORCPT ); Tue, 10 May 2016 04:43:54 -0400 Date: Tue, 10 May 2016 01:42:48 -0700 From: tip-bot for Kees Cook Message-ID: Cc: dvlasenk@redhat.com, yinghai@kernel.org, akpm@linux-foundation.org, tglx@linutronix.de, peterz@infradead.org, bp@suse.de, keescook@chromium.org, torvalds@linux-foundation.org, dyoung@redhat.com, vgoyal@redhat.com, bp@alien8.de, hpa@zytor.com, luto@kernel.org, mingo@kernel.org, bhe@redhat.com, luto@amacapital.net, brgerst@gmail.com, linux-kernel@vger.kernel.org Reply-To: mingo@kernel.org, luto@kernel.org, hpa@zytor.com, bp@alien8.de, luto@amacapital.net, bhe@redhat.com, brgerst@gmail.com, linux-kernel@vger.kernel.org, akpm@linux-foundation.org, tglx@linutronix.de, dvlasenk@redhat.com, yinghai@kernel.org, peterz@infradead.org, bp@suse.de, keescook@chromium.org, torvalds@linux-foundation.org, vgoyal@redhat.com, dyoung@redhat.com In-Reply-To: <1462825332-10505-7-git-send-email-keescook@chromium.org> References: <1462825332-10505-7-git-send-email-keescook@chromium.org> To: linux-tip-commits@vger.kernel.org Subject: [tip:x86/boot] x86/KASLR: Clarify purpose of each get_random_long() Git-Commit-ID: d2d3462f9f08da364c8fbd41e8e32229d610d49d 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: d2d3462f9f08da364c8fbd41e8e32229d610d49d Gitweb: http://git.kernel.org/tip/d2d3462f9f08da364c8fbd41e8e32229d610d49d Author: Kees Cook AuthorDate: Mon, 9 May 2016 13:22:09 -0700 Committer: Ingo Molnar CommitDate: Tue, 10 May 2016 10:12:08 +0200 x86/KASLR: Clarify purpose of each get_random_long() KASLR will be calling get_random_long() twice, but the debug output won't distinguishing between them. This patch adds a report on when it is fetching the physical vs virtual address. With this, once the virtual offset is separate, the report changes from: KASLR using RDTSC... KASLR using RDTSC... into: Physical KASLR using RDTSC... Virtual KASLR using RDTSC... Signed-off-by: Kees Cook Cc: Andrew Morton Cc: Andy Lutomirski Cc: Andy Lutomirski Cc: Baoquan He Cc: Borislav Petkov Cc: Borislav Petkov Cc: Brian Gerst Cc: Dave Young Cc: Denys Vlasenko Cc: H. Peter Anvin Cc: Linus Torvalds Cc: Peter Zijlstra Cc: Thomas Gleixner Cc: Vivek Goyal Cc: Yinghai Lu Cc: kernel-hardening@lists.openwall.com Cc: lasse.collin@tukaani.org Link: http://lkml.kernel.org/r/1462825332-10505-7-git-send-email-keescook@chromium.org Signed-off-by: Ingo Molnar --- arch/x86/boot/compressed/kaslr.c | 9 +++++---- 1 file changed, 5 insertions(+), 4 deletions(-) diff --git a/arch/x86/boot/compressed/kaslr.c b/arch/x86/boot/compressed/kaslr.c index 016a4f4..cfeb025 100644 --- a/arch/x86/boot/compressed/kaslr.c +++ b/arch/x86/boot/compressed/kaslr.c @@ -72,7 +72,7 @@ static unsigned long get_random_boot(void) return hash; } -static unsigned long get_random_long(void) +static unsigned long get_random_long(const char *purpose) { #ifdef CONFIG_X86_64 const unsigned long mix_const = 0x5d6008cbf3848dd3UL; @@ -82,7 +82,8 @@ static unsigned long get_random_long(void) unsigned long raw, random = get_random_boot(); bool use_i8254 = true; - debug_putstr("KASLR using"); + debug_putstr(purpose); + debug_putstr(" KASLR using"); if (has_cpuflag(X86_FEATURE_RDRAND)) { debug_putstr(" RDRAND"); @@ -365,7 +366,7 @@ static unsigned long slots_fetch_random(void) if (slot_max == 0) return 0; - return slots[get_random_long() % slot_max]; + return slots[get_random_long("Physical") % slot_max]; } static void process_e820_entry(struct e820entry *entry, @@ -453,7 +454,7 @@ static unsigned long find_random_virt_addr(unsigned long minimum, slots = (KERNEL_IMAGE_SIZE - minimum - image_size) / CONFIG_PHYSICAL_ALIGN + 1; - random_addr = get_random_long() % slots; + random_addr = get_random_long("Virtual") % slots; return random_addr * CONFIG_PHYSICAL_ALIGN + minimum; }