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Date: Tue, 19 Feb 2013 16:08:38 +0100
From: Ingo Molnar <mingo@...nel.org>
To: Linus Torvalds <torvalds@...ux-foundation.org>
Cc: linux-kernel@...r.kernel.org, "H. Peter Anvin" <hpa@...or.com>,
Thomas Gleixner <tglx@...utronix.de>,
Andrew Morton <akpm@...ux-foundation.org>
Subject: [GIT PULL] x86/boot change for v3.9
Linus,
Please pull the latest x86-boot-for-linus git tree from:
git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip.git x86-boot-for-linus
HEAD: 5dcd14ecd41ea2b3ae3295a9b30d98769d52165f x86, boot: Sanitize boot_params if not zeroed on creation
Deal with bootloaders which fail to initialize unknown fields in
boot_params to zero, by sanitizing boot params passed in.
This unbreaks versions of kexec-utils. Other bootloaders do not
appear to show sensitivity to this change, but it's a
possibility for breakage nevertheless.
Thanks,
Ingo
------------------>
H. Peter Anvin (1):
x86, boot: Sanitize boot_params if not zeroed on creation
arch/x86/boot/compressed/misc.c | 2 ++
arch/x86/boot/compressed/misc.h | 1 +
arch/x86/include/asm/bootparam_utils.h | 38 ++++++++++++++++++++++++++++++++++
arch/x86/kernel/head32.c | 3 +++
arch/x86/kernel/head64.c | 2 ++
5 files changed, 46 insertions(+)
create mode 100644 arch/x86/include/asm/bootparam_utils.h
diff --git a/arch/x86/boot/compressed/misc.c b/arch/x86/boot/compressed/misc.c
index 88f7ff6..7cb56c6 100644
--- a/arch/x86/boot/compressed/misc.c
+++ b/arch/x86/boot/compressed/misc.c
@@ -325,6 +325,8 @@ asmlinkage void decompress_kernel(void *rmode, memptr heap,
{
real_mode = rmode;
+ sanitize_boot_params(real_mode);
+
if (real_mode->screen_info.orig_video_mode == 7) {
vidmem = (char *) 0xb0000;
vidport = 0x3b4;
diff --git a/arch/x86/boot/compressed/misc.h b/arch/x86/boot/compressed/misc.h
index 0e6dc0e..674019d 100644
--- a/arch/x86/boot/compressed/misc.h
+++ b/arch/x86/boot/compressed/misc.h
@@ -18,6 +18,7 @@
#include <asm/page.h>
#include <asm/boot.h>
#include <asm/bootparam.h>
+#include <asm/bootparam_utils.h>
#define BOOT_BOOT_H
#include "../ctype.h"
diff --git a/arch/x86/include/asm/bootparam_utils.h b/arch/x86/include/asm/bootparam_utils.h
new file mode 100644
index 0000000..5b5e9cb
--- /dev/null
+++ b/arch/x86/include/asm/bootparam_utils.h
@@ -0,0 +1,38 @@
+#ifndef _ASM_X86_BOOTPARAM_UTILS_H
+#define _ASM_X86_BOOTPARAM_UTILS_H
+
+#include <asm/bootparam.h>
+
+/*
+ * This file is included from multiple environments. Do not
+ * add completing #includes to make it standalone.
+ */
+
+/*
+ * Deal with bootloaders which fail to initialize unknown fields in
+ * boot_params to zero. The list fields in this list are taken from
+ * analysis of kexec-tools; if other broken bootloaders initialize a
+ * different set of fields we will need to figure out how to disambiguate.
+ *
+ */
+static void sanitize_boot_params(struct boot_params *boot_params)
+{
+ if (boot_params->sentinel) {
+ /*fields in boot_params are not valid, clear them */
+ memset(&boot_params->olpc_ofw_header, 0,
+ (char *)&boot_params->alt_mem_k -
+ (char *)&boot_params->olpc_ofw_header);
+ memset(&boot_params->kbd_status, 0,
+ (char *)&boot_params->hdr -
+ (char *)&boot_params->kbd_status);
+ memset(&boot_params->_pad7[0], 0,
+ (char *)&boot_params->edd_mbr_sig_buffer[0] -
+ (char *)&boot_params->_pad7[0]);
+ memset(&boot_params->_pad8[0], 0,
+ (char *)&boot_params->eddbuf[0] -
+ (char *)&boot_params->_pad8[0]);
+ memset(&boot_params->_pad9[0], 0, sizeof(boot_params->_pad9));
+ }
+}
+
+#endif /* _ASM_X86_BOOTPARAM_UTILS_H */
diff --git a/arch/x86/kernel/head32.c b/arch/x86/kernel/head32.c
index c18f59d..6773c91 100644
--- a/arch/x86/kernel/head32.c
+++ b/arch/x86/kernel/head32.c
@@ -18,6 +18,7 @@
#include <asm/io_apic.h>
#include <asm/bios_ebda.h>
#include <asm/tlbflush.h>
+#include <asm/bootparam_utils.h>
static void __init i386_default_early_setup(void)
{
@@ -30,6 +31,8 @@ static void __init i386_default_early_setup(void)
void __init i386_start_kernel(void)
{
+ sanitize_boot_params(&boot_params);
+
memblock_reserve(__pa_symbol(&_text),
__pa_symbol(&__bss_stop) - __pa_symbol(&_text));
diff --git a/arch/x86/kernel/head64.c b/arch/x86/kernel/head64.c
index 037df57..849fc9e 100644
--- a/arch/x86/kernel/head64.c
+++ b/arch/x86/kernel/head64.c
@@ -25,6 +25,7 @@
#include <asm/kdebug.h>
#include <asm/e820.h>
#include <asm/bios_ebda.h>
+#include <asm/bootparam_utils.h>
static void __init zap_identity_mappings(void)
{
@@ -46,6 +47,7 @@ static void __init copy_bootdata(char *real_mode_data)
char * command_line;
memcpy(&boot_params, real_mode_data, sizeof boot_params);
+ sanitize_boot_params(&boot_params);
if (boot_params.hdr.cmd_line_ptr) {
command_line = __va(boot_params.hdr.cmd_line_ptr);
memcpy(boot_command_line, command_line, COMMAND_LINE_SIZE);
--
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