The current KASLR implementation randomizes the physical and virtual
addresses of the kernel together (both are offset by the same amount). It
calculates the delta of the physical address where vmlinux was linked
to load and where it is finally loaded. If the delta is not equal to 0
(i.e. the kernel was relocated), relocation handling needs be done.
On 64-bit, this patch randomizes both the physical address where kernel
is decompressed and the virtual address where kernel text is mapped and
will execute from. We now have two values being chosen, so the function
arguments are reorganized to pass by pointer so they can be directly
updated. Since relocation handling only depends on the virtual address,
we must check the virtual delta, not the physical delta for processing
kernel relocations. This also populates the page table for the new
virtual address range. 32-bit does not support a separate virtual address,
so it continues to use the physical offset for its virtual offset.
Additionally updates the sanity checks done on the resulting kernel
addresses since they are potentially separate now.
[kees: rewrote changelog, limited virtual split to 64-bit only, update checks]
[kees: fix CONFIG_RANDOMIZE_BASE=n boot failure]
Signed-off-by: Baoquan He <bhe@redhat.com>
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: 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/1464216334-17200-4-git-send-email-keescook@chromium.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
This extracts the call to prepare_level4() into a top-level function
that the user of the pagetable.c interface must call to initialize
the new page tables. For clarity and to match the "finalize" function,
it has been renamed to initialize_identity_maps(). This function also
gains the initialization of mapping_info so we don't have to do it each
time in add_identity_map().
Additionally add copyright notice to the top, to make it clear that the
bulk of the pagetable.c code was written by Yinghai, and that I just
added bugs later. :)
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/1464216334-17200-3-git-send-email-keescook@chromium.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Currently KASLR only supports relocation in a small physical range (from
16M to 1G), due to using the initial kernel page table identity mapping.
To support ranges above this, we need to have an identity mapping for the
desired memory range before we can decompress (and later run) the kernel.
32-bit kernels already have the needed identity mapping. This patch adds
identity mappings for the needed memory ranges on 64-bit kernels. This
happens in two possible boot paths:
If loaded via startup_32(), we need to set up the needed identity map.
If loaded from a 64-bit bootloader, the bootloader will have already
set up an identity mapping, and we'll start via the compressed kernel's
startup_64(). In this case, the bootloader's page tables need to be
avoided while selecting the new uncompressed kernel location. If not,
the decompressor could overwrite them during decompression.
To accomplish this, we could walk the pagetable and find every page
that is used, and add them to mem_avoid, but this needs extra code and
will require increasing the size of the mem_avoid array.
Instead, we can create a new set of page tables for our own identity
mapping instead. The pages for the new page table will come from the
_pagetable section of the compressed kernel, which means they are
already contained by in mem_avoid array. To do this, we reuse the code
from the uncompressed kernel's identity mapping routines.
The _pgtable will be shared by both the 32-bit and 64-bit paths to reduce
init_size, as now the compressed kernel's _rodata to _end will contribute
to init_size.
To handle the possible mappings, we need to increase the existing page
table buffer size:
When booting via startup_64(), we need to cover the old VO, params,
cmdline and uncompressed kernel. In an extreme case we could have them
all beyond the 512G boundary, which needs (2+2)*4 pages with 2M mappings.
And we'll need 2 for first 2M for VGA RAM. One more is needed for level4.
This gets us to 19 pages total.
When booting via startup_32(), KASLR could move the uncompressed kernel
above 4G, so we need to create extra identity mappings, which should only
need (2+2) pages at most when it is beyond the 512G boundary. So 19
pages is sufficient for this case as well.
The resulting BOOT_*PGT_SIZE defines use the "_SIZE" suffix on their
names to maintain logical consistency with the existing BOOT_HEAP_SIZE
and BOOT_STACK_SIZE defines.
This patch is based on earlier patches from Yinghai Lu and Baoquan He.
Signed-off-by: Kees Cook <keescook@chromium.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Baoquan He <bhe@redhat.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Borislav Petkov <bp@suse.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Dave Young <dyoung@redhat.com>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Jiri Kosina <jkosina@suse.cz>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Vivek Goyal <vgoyal@redhat.com>
Cc: Yinghai Lu <yinghai@kernel.org>
Cc: kernel-hardening@lists.openwall.com
Cc: lasse.collin@tukaani.org
Link: http://lkml.kernel.org/r/1462572095-11754-4-git-send-email-keescook@chromium.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Currently extract_kernel() defines the input and output buffer pointers
as "unsigned char *" since that's effectively what they are. It passes
these to the decompressor routine and to the ELF parser, which both
logically deal with buffer pointers too. There is some casting ("unsigned
long") done to validate the numerical value of the pointers, but it is
relatively limited.
However, choose_random_location() operates almost exclusively on the
numerical representation of these pointers, so it ended up carrying
a lot of "unsigned long" casts. With the future physical/virtual split
these casts were going to multiply, so this attempts to solve the
problem by doing all the casting in choose_random_location()'s entry
and return instead of through-out the code. Adjusts argument names to
be more meaningful, and changes one us of "choice" to "output" to make
the future physical/virtual split more clear (i.e. "choice" should be
strictly a function return value and not used as an intermediate).
Suggested-by: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Kees Cook <keescook@chromium.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Andy Lutomirski <luto@amacapital.net>
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: Dave Young <dyoung@redhat.com>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Vivek Goyal <vgoyal@redhat.com>
Cc: Yinghai Lu <yinghai@kernel.org>
Cc: kernel-hardening@lists.openwall.com
Cc: lasse.collin@tukaani.org
Link: http://lkml.kernel.org/r/1462486436-3707-2-git-send-email-keescook@chromium.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Currently to use warn(), a caller would need to include misc.h. However,
this means they would get the (unavailable during compressed boot)
gcc built-in memcpy family of functions. But since string.c is defining
these memcpy functions for use by misc.c, we end up in a weird circular
dependency.
To break this loop, move the error reporting functions outside of misc.c
with their own header so that they can be independently included by
other sources. Since the screen-writing routines use memmove(), keep the
low-level *_putstr() functions in misc.c.
Signed-off-by: Kees Cook <keescook@chromium.org>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Baoquan He <bhe@redhat.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Borislav Petkov <bp@suse.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Lasse Collin <lasse.collin@tukaani.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: One Thousand Gnomes <gnomes@lxorguk.ukuu.org.uk>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Yinghai Lu <yinghai@kernel.org>
Link: http://lkml.kernel.org/r/1462229461-3370-2-git-send-email-keescook@chromium.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
If KASLR is built in but not available at run-time (either due to the
current conflict with hibernation, command-line request, or e820 parsing
failures), announce the state explicitly. To support this, a new "warn"
function is created, based on the existing "error" function.
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@amacapital.net>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Baoquan He <bhe@redhat.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Borislav Petkov <bp@suse.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/1461185746-8017-6-git-send-email-keescook@chromium.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
The name "choose_kernel_location" isn't specific enough, and doesn't
describe the primary thing it does: choosing a random location. This
patch renames it to "choose_random_location", and clarifies the what
routines are contained in the kaslr.c source file.
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@amacapital.net>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Baoquan He <bhe@redhat.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Borislav Petkov <bp@suse.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/1460997735-24785-6-git-send-email-keescook@chromium.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
The non-compressed boot code uses the (much more obvious) name
"boot_params" for the global pointer to the x86 boot parameters. The
compressed kernel loader code, though, was using the legacy name
"real_mode". There is no need to have a different name, and changing it
improves readability.
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@amacapital.net>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Baoquan He <bhe@redhat.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Borislav Petkov <bp@suse.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/1460997735-24785-4-git-send-email-keescook@chromium.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Since the boot_params can be found using the real_mode global variable,
there is no need to pass around a pointer to it. This slightly simplifies
the choose_kernel_location function and its callers.
[kees: rewrote changelog, tracked file rename]
Signed-off-by: Yinghai Lu <yinghai@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@amacapital.net>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Baoquan He <bhe@redhat.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Borislav Petkov <bp@suse.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>
Link: http://lkml.kernel.org/r/1460997735-24785-3-git-send-email-keescook@chromium.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
In order to avoid confusion over what this file provides, rename it to
kaslr.c since it is used exclusively for the kernel ASLR, not userspace
ASLR.
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@amacapital.net>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Baoquan He <bhe@redhat.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Borislav Petkov <bp@suse.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/1460997735-24785-2-git-send-email-keescook@chromium.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
This is useful for reporting various addresses or other values
while debugging early boot, for example, the recent kernel image
size vs kernel run size. For example, when
CONFIG_X86_VERBOSE_BOOTUP is set, this is now visible at boot
time:
early console in setup code
early console in decompress_kernel
input_data: 0x0000000001e1526e
input_len: 0x0000000000732236
output: 0x0000000001000000
output_len: 0x0000000001535640
run_size: 0x00000000021fb000
KASLR using RDTSC...
Signed-off-by: Kees Cook <keescook@chromium.org>
Cc: Andrey Ryabinin <a.ryabinin@samsung.com>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Borislav Petkov <bp@suse.de>
Cc: Jan Beulich <JBeulich@suse.com>
Cc: Jiri Kosina <jkosina@suse.cz>
Cc: Joe Perches <joe@perches.com>
Cc: Josh Triplett <josh@joshtriplett.org>
Cc: Junjie Mao <eternal.n08@gmail.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Vivek Goyal <vgoyal@redhat.com>
Cc: Yinghai Lu <yinghai@kernel.org>
Link: http://lkml.kernel.org/r/20150706230620.GA17501@www.outflux.net
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Linus reported the following new warning on x86 allmodconfig with GCC 5.1:
> ./arch/x86/include/asm/spinlock.h: In function ‘arch_spin_lock’:
> ./arch/x86/include/asm/spinlock.h:119:3: warning: implicit declaration
> of function ‘__ticket_lock_spinning’ [-Wimplicit-function-declaration]
> __ticket_lock_spinning(lock, inc.tail);
> ^
This warning triggers because of these hacks in misc.h:
/*
* we have to be careful, because no indirections are allowed here, and
* paravirt_ops is a kind of one. As it will only run in baremetal anyway,
* we just keep it from happening
*/
#undef CONFIG_PARAVIRT
#undef CONFIG_KASAN
But these hacks were not updated when CONFIG_PARAVIRT_SPINLOCKS was added,
and eventually (with the introduction of queued paravirt spinlocks in
recent kernels) this created an invalid Kconfig combination and broke
the build.
So add a CONFIG_PARAVIRT_SPINLOCKS #undef line as well.
Also remove the _ASM_X86_DESC_H quirk: that undocumented quirk
was originally added ages ago, in:
099e137726 ("x86: use ELF format in compressed images.")
and I went back to that kernel (and fixed up the main Makefile
which didn't build anymore) and checked what failure it
avoided: it avoided an include file dependencies related
build failure related to our old x86-platforms code.
That old code is long gone, the header dependencies got cleaned
up, and the build does not fail anymore with the totality of
asm/desc.h included - so remove the quirk.
Reported-by: Linus Torvalds <torvalds@linux-foundation.org>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Commit:
e2b32e6785 ("x86, kaslr: randomize module base load address")
made module base address randomization unconditional and didn't regard
disabled KKASLR due to CONFIG_HIBERNATION and command line option
"nokaslr". For more info see (now reverted) commit:
f47233c2d3 ("x86/mm/ASLR: Propagate base load address calculation")
In order to propagate KASLR status to kernel proper, we need a single bit
in boot_params.hdr.loadflags and we've chosen bit 1 thus leaving the
top-down allocated bits for bits supposed to be used by the bootloader.
Originally-From: Jiri Kosina <jkosina@suse.cz>
Suggested-by: H. Peter Anvin <hpa@zytor.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Cc: Kees Cook <keescook@chromium.org>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
This reverts commit:
f47233c2d3 ("x86/mm/ASLR: Propagate base load address calculation")
The main reason for the revert is that the new boot flag does not work
at all currently, and in order to make this work, we need non-trivial
changes to the x86 boot code which we didn't manage to get done in
time for merging.
And even if we did, they would've been too risky so instead of
rushing things and break booting 4.1 on boxes left and right, we
will be very strict and conservative and will take our time with
this to fix and test it properly.
Reported-by: Yinghai Lu <yinghai@kernel.org>
Signed-off-by: Borislav Petkov <bp@suse.de>
Cc: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Cc: Baoquan He <bhe@redhat.com>
Cc: H. Peter Anvin <hpa@linux.intel.com
Cc: Jiri Kosina <jkosina@suse.cz>
Cc: Josh Triplett <josh@joshtriplett.org>
Cc: Junjie Mao <eternal.n08@gmail.com>
Cc: Kees Cook <keescook@chromium.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Matt Fleming <matt.fleming@intel.com>
Link: http://lkml.kernel.org/r/20150316100628.GD22995@pd.tnic
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Pull misc x86 fixes from Ingo Molnar:
"This contains:
- EFI fixes
- a boot printout fix
- ASLR/kASLR fixes
- intel microcode driver fixes
- other misc fixes
Most of the linecount comes from an EFI revert"
* 'x86-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
x86/mm/ASLR: Avoid PAGE_SIZE redefinition for UML subarch
x86/microcode/intel: Handle truncated microcode images more robustly
x86/microcode/intel: Guard against stack overflow in the loader
x86, mm/ASLR: Fix stack randomization on 64-bit systems
x86/mm/init: Fix incorrect page size in init_memory_mapping() printks
x86/mm/ASLR: Propagate base load address calculation
Documentation/x86: Fix path in zero-page.txt
x86/apic: Fix the devicetree build in certain configs
Revert "efi/libstub: Call get_memory_map() to obtain map and desc sizes"
x86/efi: Avoid triple faults during EFI mixed mode calls
Commit:
e2b32e6785 ("x86, kaslr: randomize module base load address")
makes the base address for module to be unconditionally randomized in
case when CONFIG_RANDOMIZE_BASE is defined and "nokaslr" option isn't
present on the commandline.
This is not consistent with how choose_kernel_location() decides whether
it will randomize kernel load base.
Namely, CONFIG_HIBERNATION disables kASLR (unless "kaslr" option is
explicitly specified on kernel commandline), which makes the state space
larger than what module loader is looking at. IOW CONFIG_HIBERNATION &&
CONFIG_RANDOMIZE_BASE is a valid config option, kASLR wouldn't be applied
by default in that case, but module loader is not aware of that.
Instead of fixing the logic in module.c, this patch takes more generic
aproach. It introduces a new bootparam setup data_type SETUP_KASLR and
uses that to pass the information whether kaslr has been applied during
kernel decompression, and sets a global 'kaslr_enabled' variable
accordingly, so that any kernel code (module loading, livepatching, ...)
can make decisions based on its value.
x86 module loader is converted to make use of this flag.
Signed-off-by: Jiri Kosina <jkosina@suse.cz>
Acked-by: Kees Cook <keescook@chromium.org>
Cc: "H. Peter Anvin" <hpa@linux.intel.com>
Link: https://lkml.kernel.org/r/alpine.LNX.2.00.1502101411280.10719@pobox.suse.cz
[ Always dump correct kaslr status when panicking ]
Signed-off-by: Borislav Petkov <bp@suse.de>
Recently instrumentation of builtin functions calls was removed from GCC
5.0. To check the memory accessed by such functions, userspace asan
always uses interceptors for them.
So now we should do this as well. This patch declares
memset/memmove/memcpy as weak symbols. In mm/kasan/kasan.c we have our
own implementation of those functions which checks memory before accessing
it.
Default memset/memmove/memcpy now now always have aliases with '__'
prefix. For files that built without kasan instrumentation (e.g.
mm/slub.c) original mem* replaced (via #define) with prefixed variants,
cause we don't want to check memory accesses there.
Signed-off-by: Andrey Ryabinin <a.ryabinin@samsung.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Konstantin Serebryany <kcc@google.com>
Cc: Dmitry Chernenkov <dmitryc@google.com>
Signed-off-by: Andrey Konovalov <adech.fo@gmail.com>
Cc: Yuri Gribov <tetra2005@gmail.com>
Cc: Konstantin Khlebnikov <koct9i@gmail.com>
Cc: Sasha Levin <sasha.levin@oracle.com>
Cc: Christoph Lameter <cl@linux.com>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: Dave Hansen <dave.hansen@intel.com>
Cc: Andi Kleen <andi@firstfloor.org>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Christoph Lameter <cl@linux.com>
Cc: Pekka Enberg <penberg@kernel.org>
Cc: David Rientjes <rientjes@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Counts available alignment positions across all e820 maps, and chooses
one randomly for the new kernel base address, making sure not to collide
with unsafe memory areas.
Signed-off-by: Kees Cook <keescook@chromium.org>
Link: http://lkml.kernel.org/r/1381450698-28710-5-git-send-email-keescook@chromium.org
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
Adds potential sources of randomness: RDRAND, RDTSC, or the i8254.
This moves the pre-alternatives inline rdrand function into the header so
both pieces of code can use it. Availability of RDRAND is then controlled
by CONFIG_ARCH_RANDOM, if someone wants to disable it even for kASLR.
Signed-off-by: Kees Cook <keescook@chromium.org>
Link: http://lkml.kernel.org/r/1381450698-28710-4-git-send-email-keescook@chromium.org
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
This allows decompress_kernel to return a new location for the kernel to
be relocated to. Additionally, enforces CONFIG_PHYSICAL_START as the
minimum relocation position when building with CONFIG_RELOCATABLE.
With CONFIG_RANDOMIZE_BASE set, the choose_kernel_location routine
will select a new location to decompress the kernel, though here it is
presently a no-op. The kernel command line option "nokaslr" is introduced
to bypass these routines.
Signed-off-by: Kees Cook <keescook@chromium.org>
Link: http://lkml.kernel.org/r/1381450698-28710-3-git-send-email-keescook@chromium.org
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
Use the new sentinel field to detect bootloaders which fail to follow
protocol and don't initialize fields in struct boot_params that they
do not explicitly initialize to zero.
Based on an original patch and research by Yinghai Lu.
Changed by hpa to be invoked both in the decompression path and in the
kernel proper; the latter for the case where a bootloader takes over
decompression.
Originally-by: Yinghai Lu <yinghai@kernel.org>
Link: http://lkml.kernel.org/r/1359058816-7615-26-git-send-email-yinghai@kernel.org
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
CONFIG_EARLY_PRINTK is the only feature that might use command line
parsing in the decompression stage. If it is disabled then we can
exclude the related code to save space. This can result in an estimated
space savings of 2240 bytes from the compressed kernel image.
Signed-off-by: Joe Millenbach <jmillenbach@gmail.com>
Link: http://lkml.kernel.org/r/1342746282-28497-8-git-send-email-jmillenbach@gmail.com
Signed-off-by: Gokul Caushik <caushik1@gmail.com>
Reviewed-by: Josh Triplett <josh@joshtriplett.org>
Signed-off-by: H. Peter Anvin <hpa@zytor.com>
Removes early_serial_console.c code if we don't have the config option that
enables it (EARLY_PRINTK). When disabling this code, make early_serial_base a
constant 0 to allow the compiler to optimize away the code that checks for
early_serial_base.
Signed-off-by: Joe Millenbach <jmillenbach@gmail.com>
Link: http://lkml.kernel.org/r/1342746282-28497-7-git-send-email-jmillenbach@gmail.com
Signed-off-by: Gokul Caushik <caushik1@gmail.com>
Reviewed-by: Josh Triplett <josh@joshtriplett.org>
Signed-off-by: H. Peter Anvin <hpa@zytor.com>
Changed putstr flagging from parameter to conditional compilation for puts,
debug_putstr, and error_putstr. This allows for space savings since most
configurations won't use this feature.
Signed-off-by: Joe Millenbach <jmillenbach@gmail.com>
Link: http://lkml.kernel.org/r/1342746282-28497-5-git-send-email-jmillenbach@gmail.com
Signed-off-by: Gokul Caushik <caushik1@gmail.com>
Reviewed-by: Josh Triplett <josh@joshtriplett.org>
Signed-off-by: H. Peter Anvin <hpa@zytor.com>
For consistency we changed the error output path to match the new debug path.
Signed-off-by: Joe Millenbach <jmillenbach@gmail.com>
Link: http://lkml.kernel.org/r/1342746282-28497-4-git-send-email-jmillenbach@gmail.com
Signed-off-by: Gokul Caushik <caushik1@gmail.com>
Reviewed-by: Josh Triplett <josh@joshtriplett.org>
Signed-off-by: H. Peter Anvin <hpa@zytor.com>
It is a subset of <ctype.h> functionality, so name it ctype.h. Also,
reorganize header files so #include statements are clustered near the
top as they should be.
Signed-off-by: H. Peter Anvin <hpa@zytor.com>
LKML-Reference: <4C5752F2.8030206@kernel.org>
This enables the decompressor output to be seen on the serial console.
Most of the code is shared with the regular boot code.
We could add printf to the decompressor if needed, but currently there
is no sufficiently compelling user.
-v2: define BOOT_BOOT_H to avoid include boot.h
-v3: early_serial_base need to be static in misc.c ?
-v4: create seperate string.c printf.c cmdline.c early_serial_console.c
after hpa's patch that allow global variables in compressed/misc stage
-v5: remove printf.c related
Signed-off-by: Yinghai Lu <yinghai@kernel.org>
Signed-off-by: H. Peter Anvin <hpa@zytor.com>
Baoquan He