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mirror of https://github.com/edk2-porting/linux-next.git synced 2024-12-24 13:13:57 +08:00
linux-next/arch/x86
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
..
boot x86, kaslr: Prevent .bss from overlaping initrd 2014-11-01 22:20:50 +01:00
configs x86: Add "make tinyconfig" to configure the tiniest possible kernel 2014-08-08 16:30:24 -07:00
crypto Revert "crypto: aesni - disable "by8" AVX CTR optimization" 2014-10-02 14:40:28 +08:00
ia32 x86_64, entry: Fix out of bounds read on sysenter 2014-10-31 18:47:09 -07:00
include sched: stop the unbound recursion in preempt_schedule_context() 2014-10-28 10:46:05 +01:00
kernel x86, microcode, AMD: Fix early ucode loading on 32-bit 2014-11-01 20:24:21 +01:00
kvm KVM: x86: Wrong assertion on paging_tmpl.h 2014-10-24 13:30:37 +02:00
lguest asmlinkage, x86: Add explicit __visible to arch/x86/* 2014-05-05 16:07:44 -07:00
lib Merge branch 'x86-asm-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2014-10-13 18:14:50 +02:00
math-emu asmlinkage, x86: Add explicit __visible to arch/x86/* 2014-05-05 16:07:44 -07:00
mm x86, pageattr: Prevent overflow in slow_virt_to_phys() for X86_PAE 2014-10-29 10:57:21 +01:00
net x86: bpf_jit: fix two bugs in eBPF JIT compiler 2014-10-14 13:13:14 -04:00
oprofile percpu: Resolve ambiguities in __get_cpu_var/cpumask_var_t 2014-08-28 08:58:57 -04:00
pci xen: features and fixes for 3.18-rc0 2014-10-11 20:29:01 -04:00
platform Merge branch 'x86-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2014-10-31 14:30:16 -07:00
power nosave: consolidate __nosave_{begin,end} in <asm/sections.h> 2014-10-09 22:26:04 -04:00
purgatory arch/x86/purgatory/Makefile: try to use automatic variable in kexec purgatory makefile 2014-10-14 02:18:21 +02:00
realmode x86/build: Supress realmode.bin is up to date message 2014-04-16 15:17:24 +02:00
syscalls bpf: enable bpf syscall on x64 and i386 2014-09-26 15:05:14 -04:00
tools x86, kaslr: Prevent .bss from overlaping initrd 2014-11-01 22:20:50 +01:00
um Merge git://git.infradead.org/users/eparis/audit 2014-10-19 16:25:56 -07:00
vdso x86/vdso: Fix vdso2c's special_pages[] error checking 2014-09-24 09:55:38 +02:00
video
xen x86/xen: panic on bad Xen-provided memory map 2014-10-23 16:24:02 +01:00
.gitignore x86/build: Add arch/x86/purgatory/ make generated files to gitignore 2014-10-09 09:29:46 +02:00
Kbuild kexec: create a new config option CONFIG_KEXEC_FILE for new syscall 2014-08-29 16:28:16 -07:00
Kconfig perf/x86: Fix compile warnings for intel_uncore 2014-10-28 10:51:03 +01:00
Kconfig.cpu Merge branch 'x86-nuke-platforms-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2014-04-02 13:15:58 -07:00
Kconfig.debug
Makefile Merge branch 'x86-build-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2014-10-13 18:17:33 +02:00
Makefile_32.cpu
Makefile.um