linux/arch/x86/boot
Kees Cook 98f7852537 x86/boot: Refuse to build with data relocations
The compressed kernel is built with -fPIC/-fPIE so that it can run in any
location a bootloader happens to put it. However, since ELF relocation
processing is not happening (and all the relocation information has
already been stripped at link time), none of the code can use data
relocations (e.g. static assignments of pointers). This is already noted
in a warning comment at the top of misc.c, but this adds an explicit
check for the condition during the linking stage to block any such bugs
from appearing.

If this was in place with the earlier bug in pagetable.c, the build
would fail like this:

  ...
    CC      arch/x86/boot/compressed/pagetable.o
    DATAREL arch/x86/boot/compressed/vmlinux
  error: arch/x86/boot/compressed/pagetable.o has data relocations!
  make[2]: *** [arch/x86/boot/compressed/vmlinux] Error 1
  ...

A clean build shows:

  ...
    CC      arch/x86/boot/compressed/pagetable.o
    DATAREL arch/x86/boot/compressed/vmlinux
    LD      arch/x86/boot/compressed/vmlinux
  ...

Suggested-by: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Kees Cook <keescook@chromium.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Andrey Ryabinin <aryabinin@virtuozzo.com>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Baoquan He <bhe@redhat.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: H.J. Lu <hjl.tools@gmail.com>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Yinghai Lu <yinghai@kernel.org>
Link: http://lkml.kernel.org/r/1464216334-17200-2-git-send-email-keescook@chromium.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2016-06-26 12:32:03 +02:00
..
compressed x86/boot: Refuse to build with data relocations 2016-06-26 12:32:03 +02:00
tools x86/boot: Remove unused 'is_big_kernel' variable 2016-02-16 09:16:58 +01:00
.gitignore x86: remove offsets.h from .gitignore and dontdiff 2012-11-19 14:10:53 +01:00
a20.c x86, setup: "glove box" BIOS interrupts in the core boot code 2009-04-09 16:08:11 -07:00
apm.c x86, setup: "glove box" BIOS interrupts in the APM code 2009-04-09 16:08:11 -07:00
bioscall.S x86, boot: Move intcall() to the .inittext section 2014-01-04 14:29:08 -08:00
bitops.h
boot.h x86/mm: Fix regression with huge pages on PAE 2015-12-04 09:14:27 +01:00
cmdline.c x86, boot: Pass cmd_line_ptr with unsigned long instead 2013-01-29 15:26:09 -08:00
code16gcc.h x86, build: Change code16gcc.h from a C header to an assembly header 2014-06-04 13:16:48 -07:00
copy.S x86, boot: Use .code16 instead of .code16gcc 2014-01-04 13:59:06 -08:00
cpu.c x86: Support compiling out human-friendly processor feature names 2014-08-17 15:54:00 -07:00
cpucheck.c Merge branch 'x86/boot' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2014-04-02 12:23:49 -07:00
cpuflags.c x86, boot: Fix word-size assumptions in has_eflag() inline asm 2014-01-30 08:04:32 -08:00
cpuflags.h x86/cpufeature: Carve out X86_FEATURE_* 2016-01-30 11:22:17 +01:00
ctype.h x86, setup: Rename BOOT_ISDIGIT_H to BOOT_CTYPE_H 2015-01-13 11:59:04 +01:00
early_serial_console.c x86/boot: Add missing file header comments 2016-05-10 10:12:03 +02:00
edd.c x86, boot: Create a separate string.h file to provide standard string functions 2014-03-19 15:43:45 -07:00
header.S x86/boot: Calculate decompression size during boot not build 2016-04-29 11:03:29 +02:00
install.sh kbuild: use INSTALLKERNEL to select customized installkernel script 2009-09-20 12:18:14 +02:00
main.c x86/boot: Obsolete the MCA sys_desc_table 2015-07-21 10:55:11 +02:00
Makefile x86, build: copy ldlinux.c32 to image.iso 2016-06-07 15:54:18 -07:00
memory.c x86, setup: When probing memory with e801, use ax/bx as a pair 2011-04-25 14:52:37 -07:00
mkcpustr.c x86/cpufeature: Carve out X86_FEATURE_* 2016-01-30 11:22:17 +01:00
mtools.conf.in
pm.c
pmjump.S
printf.c x86/boot: Fix a sanity check in printf.c 2013-08-14 11:48:41 +02:00
regs.c x86, boot: Create a separate string.h file to provide standard string functions 2014-03-19 15:43:45 -07:00
setup.ld x86, boot: Define the 2.12 bzImage boot protocol 2013-01-27 15:56:37 -08:00
string.c x86/boot: Standardize strcmp() 2015-03-23 10:24:12 +01:00
string.h x86, boot: Move memcmp() into string.h and string.c 2014-03-19 15:44:04 -07:00
tty.c x86, setup: reorganize the early console setup 2010-08-02 15:51:56 -07:00
version.c kbuild: move utsrelease.h to include/generated 2009-12-12 13:08:15 +01:00
vesa.h
video-bios.c x86: fix usage of bios intcall() 2009-07-04 12:56:32 -07:00
video-mode.c x86/mm: Fix regression with huge pages on PAE 2015-12-04 09:14:27 +01:00
video-vesa.c x86, boot: Create a separate string.h file to provide standard string functions 2014-03-19 15:43:45 -07:00
video-vga.c x86, setup: Set ax register in boot vga query 2010-06-10 15:24:29 -07:00
video.c x86/mm: Fix regression with huge pages on PAE 2015-12-04 09:14:27 +01:00
video.h x86/boot/video: Move the 'video_segment' variable to video.c 2015-02-19 00:25:05 +01:00