Junjie Mao e6023367d7 x86, kaslr: Prevent .bss from overlaping initrd ... When choosing a random address, the current implementation does not take into account the reversed space for .bss and .brk sections. Thus the relocated kernel may overlap other components in memory. Here is an example of the overlap from a x86_64 kernel in qemu (the ranges of physical addresses are presented): Physical Address 0x0fe00000 --+--------------------+ <-- randomized base / | relocated kernel | vmlinux.bin | (from vmlinux.bin) | 0x1336d000 (an ELF file) +--------------------+-- \ | | \ 0x1376d870 --+--------------------+ | | relocs table | | 0x13c1c2a8 +--------------------+ .bss and .brk | | | 0x13ce6000 +--------------------+ | | | / 0x13f77000 | initrd |-- | | 0x13fef374 +--------------------+ The initrd image will then be overwritten by the memset during early initialization: [ 1.655204] Unpacking initramfs... [ 1.662831] Initramfs unpacking failed: junk in compressed archive This patch prevents the above situation by requiring a larger space when looking for a random kernel base, so that existing logic can effectively avoids the overlap. [kees: switched to perl to avoid hex translation pain in mawk vs gawk] [kees: calculated overlap without relocs table] Fixes: 82fa9637a2 ("x86, kaslr: Select random position from e820 maps") Reported-by: Fengguang Wu <fengguang.wu@intel.com> Signed-off-by: Junjie Mao <eternal.n08@gmail.com> Signed-off-by: Kees Cook <keescook@chromium.org> Cc: Josh Triplett <josh@joshtriplett.org> Cc: Matt Fleming <matt.fleming@intel.com> Cc: Ard Biesheuvel <ard.biesheuvel@linaro.org> Cc: Vivek Goyal <vgoyal@redhat.com> Cc: Andi Kleen <ak@linux.intel.com> Cc: stable@vger.kernel.org Link: http://lkml.kernel.org/r/1414762838-13067-1-git-send-email-eternal.n08@gmail.com Signed-off-by: Thomas Gleixner <tglx@linutronix.de>		2014-11-01 22:20:50 +01:00
..
compressed	x86, kaslr: Prevent .bss from overlaping initrd	2014-11-01 22:20:50 +01:00
tools	x86/efi: Include a .bss section within the PE/COFF headers	2014-07-10 14:21:39 +01:00
.gitignore
a20.c
apm.c
bioscall.S
bitops.h
boot.h	x86, boot: Move memcmp() into string.h and string.c	2014-03-19 15:44:04 -07:00
cmdline.c
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
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
cpuflags.h
ctype.h
early_serial_console.c
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	Merge branch 'x86-efi-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip	2014-08-04 17:13:50 -07:00
install.sh
main.c	x86, boot: Create a separate string.h file to provide standard string functions	2014-03-19 15:43:45 -07:00
Makefile	x86: Support compiling out human-friendly processor feature names	2014-08-17 15:54:00 -07:00
mca.c
memory.c
mkcpustr.c	x86: Introduce disabled-features	2014-09-11 14:30:02 -07:00
mtools.conf.in
pm.c
pmjump.S
printf.c
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
string.c	x86, boot: Remove misc.h inclusion from compressed/string.c	2014-05-08 08:00:06 -07:00
string.h	x86, boot: Move memcmp() into string.h and string.c	2014-03-19 15:44:04 -07:00
tty.c
version.c
vesa.h
video-bios.c
video-mode.c
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
video.c
video.h