From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932189AbcELT2q (ORCPT ); Thu, 12 May 2016 15:28:46 -0400 Received: from mail-pf0-f175.google.com ([209.85.192.175]:33149 "EHLO mail-pf0-f175.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753130AbcELT2o (ORCPT ); Thu, 12 May 2016 15:28:44 -0400 From: Thomas Garnier To: "H . Peter Anvin" , Thomas Gleixner , Ingo Molnar , Borislav Petkov , Andy Lutomirski , Thomas Garnier , Dmitry Vyukov , Paolo Bonzini , Dan Williams , Kees Cook , Stephen Smalley , Kefeng Wang , Jonathan Corbet , Matt Fleming , Toshi Kani , Alexander Kuleshov , Alexander Popov , Joerg Roedel , Dave Young , Baoquan He , Dave Hansen , Mark Salter , Boris Ostrovsky Cc: x86@kernel.org, linux-kernel@vger.kernel.org, linux-doc@vger.kernel.org, gthelen@google.com, kernel-hardening@lists.openwall.com Subject: [PATCH v5 1/4] x86, boot: Refactor KASLR entropy functions Date: Thu, 12 May 2016 12:28:17 -0700 Message-Id: <1463081300-11127-2-git-send-email-thgarnie@google.com> X-Mailer: git-send-email 2.8.0.rc3.226.g39d4020 In-Reply-To: <1463081300-11127-1-git-send-email-thgarnie@google.com> References: <1463081300-11127-1-git-send-email-thgarnie@google.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Move the KASLR entropy functions in x86/libray to be used in early kernel boot for KASLR memory randomization. Signed-off-by: Thomas Garnier --- Based on next-20160511 --- arch/x86/boot/compressed/kaslr.c | 77 +++------------------------------- arch/x86/include/asm/kaslr.h | 6 +++ arch/x86/lib/Makefile | 1 + arch/x86/lib/kaslr.c | 90 ++++++++++++++++++++++++++++++++++++++++ 4 files changed, 102 insertions(+), 72 deletions(-) create mode 100644 arch/x86/include/asm/kaslr.h create mode 100644 arch/x86/lib/kaslr.c diff --git a/arch/x86/boot/compressed/kaslr.c b/arch/x86/boot/compressed/kaslr.c index cfeb025..2d8cbd9 100644 --- a/arch/x86/boot/compressed/kaslr.c +++ b/arch/x86/boot/compressed/kaslr.c @@ -12,10 +12,6 @@ #include "misc.h" #include "error.h" -#include -#include -#include - #include #include #include @@ -26,26 +22,6 @@ static const char build_str[] = UTS_RELEASE " (" LINUX_COMPILE_BY "@" LINUX_COMPILE_HOST ") (" LINUX_COMPILER ") " UTS_VERSION; -#define I8254_PORT_CONTROL 0x43 -#define I8254_PORT_COUNTER0 0x40 -#define I8254_CMD_READBACK 0xC0 -#define I8254_SELECT_COUNTER0 0x02 -#define I8254_STATUS_NOTREADY 0x40 -static inline u16 i8254(void) -{ - u16 status, timer; - - do { - outb(I8254_PORT_CONTROL, - I8254_CMD_READBACK | I8254_SELECT_COUNTER0); - status = inb(I8254_PORT_COUNTER0); - timer = inb(I8254_PORT_COUNTER0); - timer |= inb(I8254_PORT_COUNTER0) << 8; - } while (status & I8254_STATUS_NOTREADY); - - return timer; -} - static unsigned long rotate_xor(unsigned long hash, const void *area, size_t size) { @@ -62,7 +38,7 @@ static unsigned long rotate_xor(unsigned long hash, const void *area, } /* Attempt to create a simple but unpredictable starting entropy. */ -static unsigned long get_random_boot(void) +static unsigned long get_boot_seed(void) { unsigned long hash = 0; @@ -72,51 +48,6 @@ static unsigned long get_random_boot(void) return hash; } -static unsigned long get_random_long(const char *purpose) -{ -#ifdef CONFIG_X86_64 - const unsigned long mix_const = 0x5d6008cbf3848dd3UL; -#else - const unsigned long mix_const = 0x3f39e593UL; -#endif - unsigned long raw, random = get_random_boot(); - bool use_i8254 = true; - - debug_putstr(purpose); - debug_putstr(" KASLR using"); - - if (has_cpuflag(X86_FEATURE_RDRAND)) { - debug_putstr(" RDRAND"); - if (rdrand_long(&raw)) { - random ^= raw; - use_i8254 = false; - } - } - - if (has_cpuflag(X86_FEATURE_TSC)) { - debug_putstr(" RDTSC"); - raw = rdtsc(); - - random ^= raw; - use_i8254 = false; - } - - if (use_i8254) { - debug_putstr(" i8254"); - random ^= i8254(); - } - - /* Circular multiply for better bit diffusion */ - asm("mul %3" - : "=a" (random), "=d" (raw) - : "a" (random), "rm" (mix_const)); - random += raw; - - debug_putstr("...\n"); - - return random; -} - struct mem_vector { unsigned long start; unsigned long size; @@ -131,7 +62,6 @@ enum mem_avoid_index { }; static struct mem_vector mem_avoid[MEM_AVOID_MAX]; - static bool mem_contains(struct mem_vector *region, struct mem_vector *item) { /* Item at least partially before region. */ @@ -360,13 +290,16 @@ static void slots_append(unsigned long addr) slots[slot_max++] = addr; } +#define KASLR_COMPRESSED_BOOT +#include "../../lib/kaslr.c" + static unsigned long slots_fetch_random(void) { /* Handle case of no slots stored. */ if (slot_max == 0) return 0; - return slots[get_random_long("Physical") % slot_max]; + return slots[kaslr_get_random_long("Physical") % slot_max]; } static void process_e820_entry(struct e820entry *entry, diff --git a/arch/x86/include/asm/kaslr.h b/arch/x86/include/asm/kaslr.h new file mode 100644 index 0000000..5547438 --- /dev/null +++ b/arch/x86/include/asm/kaslr.h @@ -0,0 +1,6 @@ +#ifndef _ASM_KASLR_H_ +#define _ASM_KASLR_H_ + +unsigned long kaslr_get_random_long(const char *purpose); + +#endif diff --git a/arch/x86/lib/Makefile b/arch/x86/lib/Makefile index 72a5767..cfa6d07 100644 --- a/arch/x86/lib/Makefile +++ b/arch/x86/lib/Makefile @@ -24,6 +24,7 @@ lib-y += usercopy_$(BITS).o usercopy.o getuser.o putuser.o lib-y += memcpy_$(BITS).o lib-$(CONFIG_RWSEM_XCHGADD_ALGORITHM) += rwsem.o lib-$(CONFIG_INSTRUCTION_DECODER) += insn.o inat.o +lib-$(CONFIG_RANDOMIZE_BASE) += kaslr.o obj-y += msr.o msr-reg.o msr-reg-export.o diff --git a/arch/x86/lib/kaslr.c b/arch/x86/lib/kaslr.c new file mode 100644 index 0000000..f7dfeda --- /dev/null +++ b/arch/x86/lib/kaslr.c @@ -0,0 +1,90 @@ +/* + * Entropy functions used on early boot for KASLR base and memory + * randomization. The base randomization is done in the compressed + * kernel and memory randomization is done early when the regular + * kernel starts. This file is included in the compressed kernel and + * normally linked in the regular. + */ +#include +#include +#include +#include +#include + +/* + * When built for the regular kernel, several functions need to be stubbed out + * or changed to their regular kernel equivalent. + */ +#ifndef KASLR_COMPRESSED_BOOT +#include +#include + +#define debug_putstr(v) early_printk(v) +#define has_cpuflag(f) boot_cpu_has(f) +#define get_boot_seed() kaslr_offset() +#endif + +#define I8254_PORT_CONTROL 0x43 +#define I8254_PORT_COUNTER0 0x40 +#define I8254_CMD_READBACK 0xC0 +#define I8254_SELECT_COUNTER0 0x02 +#define I8254_STATUS_NOTREADY 0x40 +static inline u16 i8254(void) +{ + u16 status, timer; + + do { + outb(I8254_PORT_CONTROL, + I8254_CMD_READBACK | I8254_SELECT_COUNTER0); + status = inb(I8254_PORT_COUNTER0); + timer = inb(I8254_PORT_COUNTER0); + timer |= inb(I8254_PORT_COUNTER0) << 8; + } while (status & I8254_STATUS_NOTREADY); + + return timer; +} + +unsigned long kaslr_get_random_long(const char *purpose) +{ +#ifdef CONFIG_X86_64 + const unsigned long mix_const = 0x5d6008cbf3848dd3UL; +#else + const unsigned long mix_const = 0x3f39e593UL; +#endif + unsigned long raw, random = get_boot_seed(); + bool use_i8254 = true; + + debug_putstr(purpose); + debug_putstr(" KASLR using"); + + if (has_cpuflag(X86_FEATURE_RDRAND)) { + debug_putstr(" RDRAND"); + if (rdrand_long(&raw)) { + random ^= raw; + use_i8254 = false; + } + } + + if (has_cpuflag(X86_FEATURE_TSC)) { + debug_putstr(" RDTSC"); + raw = rdtsc(); + + random ^= raw; + use_i8254 = false; + } + + if (use_i8254) { + debug_putstr(" i8254"); + random ^= i8254(); + } + + /* Circular multiply for better bit diffusion */ + asm("mul %3" + : "=a" (random), "=d" (raw) + : "a" (random), "rm" (mix_const)); + random += raw; + + debug_putstr("...\n"); + + return random; +} -- 2.8.0.rc3.226.g39d4020