Commit Graph

593 Commits

Author SHA1 Message Date
Lukas Wunner
db4545d9a7 x86/efi: Deduplicate efi_char16_printk()
Eliminate the separate 32-bit and 64x- bit code paths by way of the shiny
new efi_call_proto() macro.

No functional change intended.

Signed-off-by: Lukas Wunner <lukas@wunner.de>
Signed-off-by: Matt Fleming <matt@codeblueprint.co.uk>
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-efi@vger.kernel.org
Link: http://lkml.kernel.org/r/1485868902-20401-3-git-send-email-ard.biesheuvel@linaro.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2017-02-01 08:45:43 +01:00
Lukas Wunner
2bd79f30ee efi: Deduplicate efi_file_size() / _read() / _close()
There's one ARM, one x86_32 and one x86_64 version which can be folded
into a single shared version by masking their differences with the shiny
new efi_call_proto() macro.

No functional change intended.

Signed-off-by: Lukas Wunner <lukas@wunner.de>
Signed-off-by: Matt Fleming <matt@codeblueprint.co.uk>
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-efi@vger.kernel.org
Link: http://lkml.kernel.org/r/1485868902-20401-2-git-send-email-ard.biesheuvel@linaro.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2017-02-01 08:45:42 +01:00
Nicholas Mc Guire
fac69d0efa x86/boot: Add missing declaration of string functions
Add the missing declarations of basic string functions to string.h to allow
a clean build.

Fixes: 5be8656615 ("String-handling functions for the new x86 setup code.")
Signed-off-by: Nicholas Mc Guire <hofrat@osadl.org>
Link: http://lkml.kernel.org/r/1483781911-21399-1-git-send-email-hofrat@osadl.org
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2017-01-09 11:53:05 +01:00
Andy Lutomirski
426d1aff31 Revert "x86/boot: Fail the boot if !M486 and CPUID is missing"
This reverts commit ed68d7e9b9.

The patch wasn't quite correct -- there are non-Intel (and hence
non-486) CPUs that we support that don't have CPUID.  Since we no
longer require CPUID for sync_core(), just revert the patch.

I think the relevant CPUs are Geode and Elan, but I'm not sure.

In principle, we should try to do better at identifying CPUID-less
CPUs in early boot, but that's more complicated.

Reported-by: One Thousand Gnomes <gnomes@lxorguk.ukuu.org.uk>
Signed-off-by: Andy Lutomirski <luto@kernel.org>
Cc: Juergen Gross <jgross@suse.com>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Matthew Whitehead <tedheadster@gmail.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Henrique de Moraes Holschuh <hmh@hmh.eng.br>
Cc: Andrew Cooper <andrew.cooper3@citrix.com>
Cc: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Cc: xen-devel <Xen-devel@lists.xen.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Link: http://lkml.kernel.org/r/82acde18a108b8e353180dd6febcc2876df33f24.1481307769.git.luto@kernel.org
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2016-12-19 11:54:20 +01:00
Linus Torvalds
a9042defa2 Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jikos/trivial
Pull trivial updates from Jiri Kosina.

* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jikos/trivial:
  NTB: correct ntb_spad_count comment typo
  misc: ibmasm: fix typo in error message
  Remove references to dead make variable LINUX_INCLUDE
  Remove last traces of ikconfig.h
  treewide: Fix printk() message errors
  Documentation/device-mapper: s/getsize/getsz/
2016-12-14 11:12:25 -08:00
Paul Bolle
846221cfb8 Remove references to dead make variable LINUX_INCLUDE
Commit 4fd06960f1 ("Use the new x86 setup code for i386") introduced a
reference to the make variable LINUX_INCLUDE. That reference got moved
around a bit and copied twice and now there are three references to it.

There has never been a definition of that variable. (Presumably that is
because it started out as a mistyped reference to LINUXINCLUDE.) So this
reference has always been an empty string. Let's remove it before it
spreads any further.

Signed-off-by: Paul Bolle <pebolle@tiscali.nl>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>
2016-12-14 10:54:28 +01:00
Linus Torvalds
06cc6b969c Merge branch 'x86-boot-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull x86 boot updates from Ingo Molnar:
 "Misc cleanups/simplifications by Borislav Petkov, Paul Bolle and Wei
  Yang"

* 'x86-boot-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  x86/boot/64: Optimize fixmap page fixup
  x86/boot: Simplify the GDTR calculation assembly code a bit
  x86/boot/build: Remove always empty $(USERINCLUDE)
2016-12-12 14:13:30 -08:00
Linus Torvalds
3940cf0b3d Merge branch 'efi-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull EFI updates from Ingo Molnar:
 "The main changes in this development cycle were:

   - Implement EFI dev path parser and other changes to fully support
     thunderbolt devices on Apple Macbooks (Lukas Wunner)

   - Add RNG seeding via the EFI stub, on ARM/arm64 (Ard Biesheuvel)

   - Expose EFI framebuffer configuration to user-space, to improve
     tooling (Peter Jones)

   - Misc fixes and cleanups (Ivan Hu, Wei Yongjun, Yisheng Xie, Dan
     Carpenter, Roy Franz)"

* 'efi-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  efi/libstub: Make efi_random_alloc() allocate below 4 GB on 32-bit
  thunderbolt: Compile on x86 only
  thunderbolt, efi: Fix Kconfig dependencies harder
  thunderbolt, efi: Fix Kconfig dependencies
  thunderbolt: Use Device ROM retrieved from EFI
  x86/efi: Retrieve and assign Apple device properties
  efi: Allow bitness-agnostic protocol calls
  efi: Add device path parser
  efi/arm*/libstub: Invoke EFI_RNG_PROTOCOL to seed the UEFI RNG table
  efi/libstub: Add random.c to ARM build
  efi: Add support for seeding the RNG from a UEFI config table
  MAINTAINERS: Add ARM and arm64 EFI specific files to EFI subsystem
  efi/libstub: Fix allocation size calculations
  efi/efivar_ssdt_load: Don't return success on allocation failure
  efifb: Show framebuffer layout as device attributes
  efi/efi_test: Use memdup_user() as a cleanup
  efi/efi_test: Fix uninitialized variable 'rv'
  efi/efi_test: Fix uninitialized variable 'datasize'
  efi/arm*: Fix efi_init() error handling
  efi: Remove unused include of <linux/version.h>
2016-12-12 10:03:44 -08:00
H.J. Lu
a980ce352f x86/build: Build compressed x86 kernels as PIE when !CONFIG_RELOCATABLE as well
Since the bootloader may load the compressed x86 kernel at any address,
it should always be built as PIE, not just when CONFIG_RELOCATABLE=y.

Otherwise, linker in binutils 2.27 will optimize GOT load into the
absolute address when building the compressed x86 kernel as a non-PIE
executable.

Signed-off-by: H.J. Lu <hjl.tools@gmail.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: H. Peter Anvin <hpa@zytor.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: linux-kernel@vger.kernel.org
[ Small wording changes. ]
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2016-11-21 11:05:28 +01:00
Andy Lutomirski
ed68d7e9b9 x86/boot: Fail the boot if !M486 and CPUID is missing
Linux will have all kinds of sporadic problems on systems that don't
have the CPUID instruction unless CONFIG_M486=y.  In particular,
sync_core() will explode.

I believe that these kernels had a better chance of working before
commit 05fb3c199b ("x86/boot: Initialize FPU and X86_FEATURE_ALWAYS
even if we don't have CPUID").  That commit inadvertently fixed a
serious bug: we used to fail to detect the FPU if CPUID wasn't
present.  Because we also used to forget to set X86_FEATURE_ALWAYS, we
end up with no cpu feature bits set at all.  This meant that
alternative patching didn't do anything and, if paravirt was disabled,
we could plausibly finish the entire boot process without calling
sync_core().

Rather than trying to work around these issues, just have the kernel
fail loudly if it's running on a CPUID-less 486, doesn't have CPUID,
and doesn't have CONFIG_M486 set.

Reported-by: Matthew Whitehead <tedheadster@gmail.com>
Signed-off-by: Andy Lutomirski <luto@kernel.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: H. Peter Anvin <hpa@zytor.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/70eac6639f23df8be5fe03fa1984aedd5d40077a.1479598603.git.luto@kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2016-11-21 09:04:32 +01:00
Lukas Wunner
58c5475aba x86/efi: Retrieve and assign Apple device properties
Apple's EFI drivers supply device properties which are needed to support
Macs optimally. They contain vital information which cannot be obtained
any other way (e.g. Thunderbolt Device ROM). They're also used to convey
the current device state so that OS drivers can pick up where EFI
drivers left (e.g. GPU mode setting).

There's an EFI driver dubbed "AAPL,PathProperties" which implements a
per-device key/value store. Other EFI drivers populate it using a custom
protocol. The macOS bootloader /System/Library/CoreServices/boot.efi
retrieves the properties with the same protocol. The kernel extension
AppleACPIPlatform.kext subsequently merges them into the I/O Kit
registry (see ioreg(8)) where they can be queried by other kernel
extensions and user space.

This commit extends the efistub to retrieve the device properties before
ExitBootServices is called. It assigns them to devices in an fs_initcall
so that they can be queried with the API in <linux/property.h>.

Note that the device properties will only be available if the kernel is
booted with the efistub. Distros should adjust their installers to
always use the efistub on Macs. grub with the "linux" directive will not
work unless the functionality of this commit is duplicated in grub.
(The "linuxefi" directive should work but is not included upstream as of
this writing.)

The custom protocol has GUID 91BD12FE-F6C3-44FB-A5B7-5122AB303AE0 and
looks like this:

typedef struct {
	unsigned long version; /* 0x10000 */
	efi_status_t (*get) (
		IN	struct apple_properties_protocol *this,
		IN	struct efi_dev_path *device,
		IN	efi_char16_t *property_name,
		OUT	void *buffer,
		IN OUT	u32 *buffer_len);
		/* EFI_SUCCESS, EFI_NOT_FOUND, EFI_BUFFER_TOO_SMALL */
	efi_status_t (*set) (
		IN	struct apple_properties_protocol *this,
		IN	struct efi_dev_path *device,
		IN	efi_char16_t *property_name,
		IN	void *property_value,
		IN	u32 property_value_len);
		/* allocates copies of property name and value */
		/* EFI_SUCCESS, EFI_OUT_OF_RESOURCES */
	efi_status_t (*del) (
		IN	struct apple_properties_protocol *this,
		IN	struct efi_dev_path *device,
		IN	efi_char16_t *property_name);
		/* EFI_SUCCESS, EFI_NOT_FOUND */
	efi_status_t (*get_all) (
		IN	struct apple_properties_protocol *this,
		OUT	void *buffer,
		IN OUT	u32 *buffer_len);
		/* EFI_SUCCESS, EFI_BUFFER_TOO_SMALL */
} apple_properties_protocol;

Thanks to Pedro Vilaça for this blog post which was helpful in reverse
engineering Apple's EFI drivers and bootloader:
https://reverse.put.as/2016/06/25/apple-efi-firmware-passwords-and-the-scbo-myth/

If someone at Apple is reading this, please note there's a memory leak
in your implementation of the del() function as the property struct is
freed but the name and value allocations are not.

Neither the macOS bootloader nor Apple's EFI drivers check the protocol
version, but we do to avoid breakage if it's ever changed. It's been the
same since at least OS X 10.6 (2009).

The get_all() function conveniently fills a buffer with all properties
in marshalled form which can be passed to the kernel as a setup_data
payload. The number of device properties is dynamic and can change
between a first invocation of get_all() (to determine the buffer size)
and a second invocation (to retrieve the actual buffer), hence the
peculiar loop which does not finish until the buffer size settles.
The macOS bootloader does the same.

The setup_data payload is later on unmarshalled in an fs_initcall. The
idea is that most buses instantiate devices in "subsys" initcall level
and drivers are usually bound to these devices in "device" initcall
level, so we assign the properties in-between, i.e. in "fs" initcall
level.

This assumes that devices to which properties pertain are instantiated
from a "subsys" initcall or earlier. That should always be the case
since on macOS, AppleACPIPlatformExpert::matchEFIDevicePath() only
supports ACPI and PCI nodes and we've fully scanned those buses during
"subsys" initcall level.

The second assumption is that properties are only needed from a "device"
initcall or later. Seems reasonable to me, but should this ever not work
out, an alternative approach would be to store the property sets e.g. in
a btree early during boot. Then whenever device_add() is called, an EFI
Device Path would have to be constructed for the newly added device,
and looked up in the btree. That way, the property set could be assigned
to the device immediately on instantiation. And this would also work for
devices instantiated in a deferred fashion. It seems like this approach
would be more complicated and require more code. That doesn't seem
justified without a specific use case.

For comparison, the strategy on macOS is to assign properties to objects
in the ACPI namespace (AppleACPIPlatformExpert::mergeEFIProperties()).
That approach is definitely wrong as it fails for devices not present in
the namespace: The NHI EFI driver supplies properties for attached
Thunderbolt devices, yet on Macs with Thunderbolt 1 only one device
level behind the host controller is described in the namespace.
Consequently macOS cannot assign properties for chained devices. With
Thunderbolt 2 they started to describe three device levels behind host
controllers in the namespace but this grossly inflates the SSDT and
still fails if the user daisy-chained more than three devices.

We copy the property names and values from the setup_data payload to
swappable virtual memory and afterwards make the payload available to
the page allocator. This is just for the sake of good housekeeping, it
wouldn't occupy a meaningful amount of physical memory (4444 bytes on my
machine). Only the payload is freed, not the setup_data header since
otherwise we'd break the list linkage and we cannot safely update the
predecessor's ->next link because there's no locking for the list.

The payload is currently not passed on to kexec'ed kernels, same for PCI
ROMs retrieved by setup_efi_pci(). This can be added later if there is
demand by amending setup_efi_state(). The payload can then no longer be
made available to the page allocator of course.

Tested-by: Lukas Wunner <lukas@wunner.de> [MacBookPro9,1]
Tested-by: Pierre Moreau <pierre.morrow@free.fr> [MacBookPro11,3]
Signed-off-by: Lukas Wunner <lukas@wunner.de>
Signed-off-by: Matt Fleming <matt@codeblueprint.co.uk>
Cc: Andreas Noever <andreas.noever@gmail.com>
Cc: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Pedro Vilaça <reverser@put.as>
Cc: Peter Jones <pjones@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: grub-devel@gnu.org
Cc: linux-efi@vger.kernel.org
Link: http://lkml.kernel.org/r/20161112213237.8804-9-matt@codeblueprint.co.uk
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2016-11-13 08:23:16 +01:00
Wei Yang
064025f7ea x86/boot: Simplify the GDTR calculation assembly code a bit
This patch calculates the GDTR's base address via a single instruction.

( EBP contains the address where it is loaded and GDTR's base address is
  already set to "gdt" in compilation. It is fine to get the correct base
  address by adding the delta to GDTR's base address. )

Signed-off-by: Wei Yang <richard.weiyang@gmail.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: H. Peter Anvin <hpa@zytor.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/1478015364-5547-1-git-send-email-richard.weiyang@gmail.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2016-11-07 08:33:59 +01:00
Paul Bolle
0acba3f918 x86/boot/build: Remove always empty $(USERINCLUDE)
Commmit b6eea87fc6:

  ("x86, boot: Explicitly include autoconf.h for hostprogs")

correctly noted:

    [...] that because $(USERINCLUDE) isn't exported by
    the top-level Makefile it's actually empty in arch/x86/boot/Makefile.

So let's do the sane thing and remove the reference to that make variable.

Signed-off-by: Paul Bolle <pebolle@tiscali.nl>
Reviewed-by: Matt Fleming <matt@codeblueprint.co.uk>
Cc: David Howells <dhowells@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/1478166468-9760-1-git-send-email-pebolle@tiscali.nl
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2016-11-07 07:30:01 +01:00
Ingo Molnar
5465fe0fc3 * Refactor the EFI memory map code into architecture neutral files
and allow drivers to permanently reserve EFI boot services regions
    on x86, as well as ARM/arm64 - Matt Fleming
 
  * Add ARM support for the EFI esrt driver - Ard Biesheuvel
 
  * Make the EFI runtime services and efivar API interruptible by
    swapping spinlocks for semaphores - Sylvain Chouleur
 
  * Provide the EFI identity mapping for kexec which allows kexec to
    work on SGI/UV platforms with requiring the "noefi" kernel command
    line parameter - Alex Thorlton
 
  * Add debugfs node to dump EFI page tables on arm64 - Ard Biesheuvel
 
  * Merge the EFI test driver being carried out of tree until now in
    the FWTS project - Ivan Hu
 
  * Expand the list of flags for classifying EFI regions as "RAM" on
    arm64 so we align with the UEFI spec - Ard Biesheuvel
 
  * Optimise out the EFI mixed mode if it's unsupported (CONFIG_X86_32)
    or disabled (CONFIG_EFI_MIXED=n) and switch the early EFI boot
    services function table for direct calls, alleviating us from
    having to maintain the custom function table - Lukas Wunner
 
  * Miscellaneous cleanups and fixes
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Merge tag 'efi-next' of git://git.kernel.org/pub/scm/linux/kernel/git/mfleming/efi into efi/core

Pull EFI updates from Matt Fleming:

"* Refactor the EFI memory map code into architecture neutral files
   and allow drivers to permanently reserve EFI boot services regions
   on x86, as well as ARM/arm64 - Matt Fleming

 * Add ARM support for the EFI esrt driver - Ard Biesheuvel

 * Make the EFI runtime services and efivar API interruptible by
   swapping spinlocks for semaphores - Sylvain Chouleur

 * Provide the EFI identity mapping for kexec which allows kexec to
   work on SGI/UV platforms with requiring the "noefi" kernel command
   line parameter - Alex Thorlton

 * Add debugfs node to dump EFI page tables on arm64 - Ard Biesheuvel

 * Merge the EFI test driver being carried out of tree until now in
   the FWTS project - Ivan Hu

 * Expand the list of flags for classifying EFI regions as "RAM" on
   arm64 so we align with the UEFI spec - Ard Biesheuvel

 * Optimise out the EFI mixed mode if it's unsupported (CONFIG_X86_32)
   or disabled (CONFIG_EFI_MIXED=n) and switch the early EFI boot
   services function table for direct calls, alleviating us from
   having to maintain the custom function table - Lukas Wunner

 * Miscellaneous cleanups and fixes"

Signed-off-by: Ingo Molnar <mingo@kernel.org>
2016-09-13 20:21:55 +02:00
Lukas Wunner
0a637ee612 x86/efi: Allow invocation of arbitrary boot services
We currently allow invocation of 8 boot services with efi_call_early().
Not included are LocateHandleBuffer and LocateProtocol in particular.
For graphics output or to retrieve PCI ROMs and Apple device properties,
we're thus forced to use the LocateHandle + AllocatePool + LocateHandle
combo, which is cumbersome and needs more code.

The ARM folks allow invocation of the full set of boot services but are
restricted to our 8 boot services in functions shared across arches.

Thus, rather than adding just LocateHandleBuffer and LocateProtocol to
struct efi_config, let's rework efi_call_early() to allow invocation of
arbitrary boot services by selecting the 64 bit vs 32 bit code path in
the macro itself.

When compiling for 32 bit or for 64 bit without mixed mode, the unused
code path is optimized away and the binary code is the same as before.
But on 64 bit with mixed mode enabled, this commit adds one compare
instruction to each invocation of a boot service and, depending on the
code path selected, two jump instructions. (Most of the time gcc
arranges the jumps in the 32 bit code path.) The result is a minuscule
performance penalty and the binary code becomes slightly larger and more
difficult to read when disassembled. This isn't a hot path, so these
drawbacks are arguably outweighed by the attainable simplification of
the C code. We have some overhead anyway for thunking or conversion
between calling conventions.

The 8 boot services can consequently be removed from struct efi_config.

No functional change intended (for now).

Example -- invocation of free_pool before (64 bit code path):
0x2d4      movq  %ds:efi_early, %rdx          ; efi_early
0x2db      movq  %ss:arg_0-0x20(%rsp), %rsi
0x2e0      xorl  %eax, %eax
0x2e2      movq  %ds:0x28(%rdx), %rdi         ; efi_early->free_pool
0x2e6      callq *%ds:0x58(%rdx)              ; efi_early->call()

Example -- invocation of free_pool after (64 / 32 bit mixed code path):
0x0dc      movq  %ds:efi_early, %rax          ; efi_early
0x0e3      cmpb  $0, %ds:0x28(%rax)           ; !efi_early->is64 ?
0x0e7      movq  %ds:0x20(%rax), %rdx         ; efi_early->call()
0x0eb      movq  %ds:0x10(%rax), %rax         ; efi_early->boot_services
0x0ef      je    $0x150
0x0f1      movq  %ds:0x48(%rax), %rdi         ; free_pool (64 bit)
0x0f5      xorl  %eax, %eax
0x0f7      callq *%rdx
...
0x150      movl  %ds:0x30(%rax), %edi         ; free_pool (32 bit)
0x153      jmp   $0x0f5

Size of eboot.o text section:
CONFIG_X86_32:                         6464 before, 6318 after
CONFIG_X86_64 && !CONFIG_EFI_MIXED:    7670 before, 7573 after
CONFIG_X86_64 &&  CONFIG_EFI_MIXED:    7670 before, 8319 after

Signed-off-by: Lukas Wunner <lukas@wunner.de>
Signed-off-by: Matt Fleming <matt@codeblueprint.co.uk>
2016-09-09 16:08:57 +01:00
Lukas Wunner
15cf7cae08 x86/efi: Remove unused find_bits() function
Left behind by commit fc37206427 ("efi/libstub: Move Graphics Output
Protocol handling to generic code").

Signed-off-by: Lukas Wunner <lukas@wunner.de>
Cc: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Signed-off-by: Matt Fleming <matt@codeblueprint.co.uk>
2016-09-09 16:08:50 +01:00
Colin Ian King
ac0e94b63e x86/efi: Initialize status to ensure garbage is not returned on small size
Although very unlikey, if size is too small or zero, then we end up with
status not being set and returning garbage. Instead, initializing status to
EFI_INVALID_PARAMETER to indicate that size is invalid in the calls to
setup_uga32 and setup_uga64.

Signed-off-by: Colin Ian King <colin.king@canonical.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Matt Fleming <matt@codeblueprint.co.uk>
2016-09-09 16:08:44 +01:00
Jeffrey Hugo
d64934019f x86/efi: Use efi_exit_boot_services()
The eboot code directly calls ExitBootServices.  This is inadvisable as the
UEFI spec details a complex set of errors, race conditions, and API
interactions that the caller of ExitBootServices must get correct.  The
eboot code attempts allocations after calling ExitBootSerives which is
not permitted per the spec.  Call the efi_exit_boot_services() helper
intead, which handles the allocation scenario properly.

Signed-off-by: Jeffrey Hugo <jhugo@codeaurora.org>
Cc: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Leif Lindholm <leif.lindholm@linaro.org>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: <stable@vger.kernel.org>
Signed-off-by: Matt Fleming <matt@codeblueprint.co.uk>
2016-09-05 12:40:16 +01:00
Jeffrey Hugo
dadb57abc3 efi/libstub: Allocate headspace in efi_get_memory_map()
efi_get_memory_map() allocates a buffer to store the memory map that it
retrieves.  This buffer may need to be reused by the client after
ExitBootServices() is called, at which point allocations are not longer
permitted.  To support this usecase, provide the allocated buffer size back
to the client, and allocate some additional headroom to account for any
reasonable growth in the map that is likely to happen between the call to
efi_get_memory_map() and the client reusing the buffer.

Signed-off-by: Jeffrey Hugo <jhugo@codeaurora.org>
Cc: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Leif Lindholm <leif.lindholm@linaro.org>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: <stable@vger.kernel.org>
Signed-off-by: Matt Fleming <matt@codeblueprint.co.uk>
2016-09-05 12:18:17 +01:00
Linus Torvalds
f716a85cd6 Merge branch 'kbuild' of git://git.kernel.org/pub/scm/linux/kernel/git/mmarek/kbuild
Pull kbuild updates from Michal Marek:

 - GCC plugin support by Emese Revfy from grsecurity, with a fixup from
   Kees Cook.  The plugins are meant to be used for static analysis of
   the kernel code.  Two plugins are provided already.

 - reduction of the gcc commandline by Arnd Bergmann.

 - IS_ENABLED / IS_REACHABLE macro enhancements by Masahiro Yamada

 - bin2c fix by Michael Tautschnig

 - setlocalversion fix by Wolfram Sang

* 'kbuild' of git://git.kernel.org/pub/scm/linux/kernel/git/mmarek/kbuild:
  gcc-plugins: disable under COMPILE_TEST
  kbuild: Abort build on bad stack protector flag
  scripts: Fix size mismatch of kexec_purgatory_size
  kbuild: make samples depend on headers_install
  Kbuild: don't add obj tree in additional includes
  Kbuild: arch: look for generated headers in obtree
  Kbuild: always prefix objtree in LINUXINCLUDE
  Kbuild: avoid duplicate include path
  Kbuild: don't add ../../ to include path
  vmlinux.lds.h: replace config_enabled() with IS_ENABLED()
  kconfig.h: allow to use IS_{ENABLE,REACHABLE} in macro expansion
  kconfig.h: use already defined macros for IS_REACHABLE() define
  export.h: use __is_defined() to check if __KSYM_* is defined
  kconfig.h: use __is_defined() to check if MODULE is defined
  kbuild: setlocalversion: print error to STDERR
  Add sancov plugin
  Add Cyclomatic complexity GCC plugin
  GCC plugin infrastructure
  Shared library support
2016-08-02 16:37:12 -04:00
Linus Torvalds
77cd3d0c43 Merge branch 'x86-boot-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull x86 boot updates from Ingo Molnar:
 "The main changes:

   - add initial commits to randomize kernel memory section virtual
     addresses, enabled via a new kernel option: RANDOMIZE_MEMORY
     (Thomas Garnier, Kees Cook, Baoquan He, Yinghai Lu)

   - enhance KASLR (RANDOMIZE_BASE) physical memory randomization (Kees
     Cook)

   - EBDA/BIOS region boot quirk cleanups (Andy Lutomirski, Ingo Molnar)

   - misc cleanups/fixes"

* 'x86-boot-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  x86/boot: Simplify EBDA-vs-BIOS reservation logic
  x86/boot: Clarify what x86_legacy_features.reserve_bios_regions does
  x86/boot: Reorganize and clean up the BIOS area reservation code
  x86/mm: Do not reference phys addr beyond kernel
  x86/mm: Add memory hotplug support for KASLR memory randomization
  x86/mm: Enable KASLR for vmalloc memory regions
  x86/mm: Enable KASLR for physical mapping memory regions
  x86/mm: Implement ASLR for kernel memory regions
  x86/mm: Separate variable for trampoline PGD
  x86/mm: Add PUD VA support for physical mapping
  x86/mm: Update physical mapping variable names
  x86/mm: Refactor KASLR entropy functions
  x86/KASLR: Fix boot crash with certain memory configurations
  x86/boot/64: Add forgotten end of function marker
  x86/KASLR: Allow randomization below the load address
  x86/KASLR: Extend kernel image physical address randomization to addresses larger than 4G
  x86/KASLR: Randomize virtual address separately
  x86/KASLR: Clarify identity map interface
  x86/boot: Refuse to build with data relocations
  x86/KASLR, x86/power: Remove x86 hibernation restrictions
2016-07-25 17:32:28 -07:00
Linus Torvalds
0f657262d5 Merge branch 'x86-mm-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull x86 mm updates from Ingo Molnar:
 "Various x86 low level modifications:

   - preparatory work to support virtually mapped kernel stacks (Andy
     Lutomirski)

   - support for 64-bit __get_user() on 32-bit kernels (Benjamin
     LaHaise)

   - (involved) workaround for Knights Landing CPU erratum (Dave Hansen)

   - MPX enhancements (Dave Hansen)

   - mremap() extension to allow remapping of the special VDSO vma, for
     purposes of user level context save/restore (Dmitry Safonov)

   - hweight and entry code cleanups (Borislav Petkov)

   - bitops code generation optimizations and cleanups with modern GCC
     (H. Peter Anvin)

   - syscall entry code optimizations (Paolo Bonzini)"

* 'x86-mm-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (43 commits)
  x86/mm/cpa: Add missing comment in populate_pdg()
  x86/mm/cpa: Fix populate_pgd(): Stop trying to deallocate failed PUDs
  x86/syscalls: Add compat_sys_preadv64v2/compat_sys_pwritev64v2
  x86/smp: Remove unnecessary initialization of thread_info::cpu
  x86/smp: Remove stack_smp_processor_id()
  x86/uaccess: Move thread_info::addr_limit to thread_struct
  x86/dumpstack: Rename thread_struct::sig_on_uaccess_error to sig_on_uaccess_err
  x86/uaccess: Move thread_info::uaccess_err and thread_info::sig_on_uaccess_err to thread_struct
  x86/dumpstack: When OOPSing, rewind the stack before do_exit()
  x86/mm/64: In vmalloc_fault(), use CR3 instead of current->active_mm
  x86/dumpstack/64: Handle faults when printing the "Stack: " part of an OOPS
  x86/dumpstack: Try harder to get a call trace on stack overflow
  x86/mm: Remove kernel_unmap_pages_in_pgd() and efi_cleanup_page_tables()
  x86/mm/cpa: In populate_pgd(), don't set the PGD entry until it's populated
  x86/mm/hotplug: Don't remove PGD entries in remove_pagetable()
  x86/mm: Use pte_none() to test for empty PTE
  x86/mm: Disallow running with 32-bit PTEs to work around erratum
  x86/mm: Ignore A/D bits in pte/pmd/pud_none()
  x86/mm: Move swap offset/type up in PTE to work around erratum
  x86/entry: Inline enter_from_user_mode()
  ...
2016-07-25 15:34:18 -07:00
Arnd Bergmann
58ab5e0c2c Kbuild: arch: look for generated headers in obtree
There are very few files that need add an -I$(obj) gcc for the preprocessor
or the assembler. For C files, we add always these for both the objtree and
srctree, but for the other ones we require the Makefile to add them, and
Kbuild then adds it for both trees.

As a preparation for changing the meaning of the -I$(obj) directive to
only refer to the srctree, this changes the two instances in arch/x86 to use
an explictit $(objtree) prefix where needed, otherwise we won't find the
headers any more, as reported by the kbuild 0day builder.

arch/x86/realmode/rm/realmode.lds.S:75:20: fatal error: pasyms.h: No such file or directory

Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Michal Marek <mmarek@suse.com>
2016-07-18 21:31:35 +02:00
Ingo Molnar
38452af242 Merge branch 'x86/asm' into x86/mm, to resolve conflicts
Conflicts:
	tools/testing/selftests/x86/Makefile

Signed-off-by: Ingo Molnar <mingo@kernel.org>
2016-07-15 10:26:04 +02:00
Dave Hansen
e4a84be6f0 x86/mm: Disallow running with 32-bit PTEs to work around erratum
The Intel(R) Xeon Phi(TM) Processor x200 Family (codename: Knights
Landing) has an erratum where a processor thread setting the Accessed
or Dirty bits may not do so atomically against its checks for the
Present bit.  This may cause a thread (which is about to page fault)
to set A and/or D, even though the Present bit had already been
atomically cleared.

These bits are truly "stray".  In the case of the Dirty bit, the
thread associated with the stray set was *not* allowed to write to
the page.  This means that we do not have to launder the bit(s); we
can simply ignore them.

If the PTE is used for storing a swap index or a NUMA migration index,
the A bit could be misinterpreted as part of the swap type.  The stray
bits being set cause a software-cleared PTE to be interpreted as a
swap entry.  In some cases (like when the swap index ends up being
for a non-existent swapfile), the kernel detects the stray value
and WARN()s about it, but there is no guarantee that the kernel can
always detect it.

When we have 64-bit PTEs (64-bit mode or 32-bit PAE), we were able
to move the swap PTE format around to avoid these troublesome bits.
But, 32-bit non-PAE is tight on bits.  So, disallow it from running
on this hardware.  I can't imagine anyone wanting to run 32-bit
non-highmem kernels on this hardware, but disallowing them from
running entirely is surely the safe thing to do.

Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Dave Hansen <dave@sr71.net>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Luis R. Rodriguez <mcgrof@suse.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Toshi Kani <toshi.kani@hp.com>
Cc: dave.hansen@intel.com
Cc: linux-mm@kvack.org
Cc: mhocko@suse.com
Link: http://lkml.kernel.org/r/20160708001914.D0B50110@viggo.jf.intel.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2016-07-13 09:43:25 +02:00
Thomas Garnier
021182e52f x86/mm: Enable KASLR for physical mapping memory regions
Add the physical mapping in the list of randomized memory regions.

The physical memory mapping holds most allocations from boot and heap
allocators. Knowing the base address and physical memory size, an attacker
can deduce the PDE virtual address for the vDSO memory page. This attack
was demonstrated at CanSecWest 2016, in the following presentation:

  "Getting Physical: Extreme Abuse of Intel Based Paged Systems":
  https://github.com/n3k/CansecWest2016_Getting_Physical_Extreme_Abuse_of_Intel_Based_Paging_Systems/blob/master/Presentation/CanSec2016_Presentation.pdf

(See second part of the presentation).

The exploits used against Linux worked successfully against 4.6+ but
fail with KASLR memory enabled:

  https://github.com/n3k/CansecWest2016_Getting_Physical_Extreme_Abuse_of_Intel_Based_Paging_Systems/tree/master/Demos/Linux/exploits

Similar research was done at Google leading to this patch proposal.

Variants exists to overwrite /proc or /sys objects ACLs leading to
elevation of privileges. These variants were tested against 4.6+.

The page offset used by the compressed kernel retains the static value
since it is not yet randomized during this boot stage.

Signed-off-by: Thomas Garnier <thgarnie@google.com>
Signed-off-by: Kees Cook <keescook@chromium.org>
Cc: Alexander Kuleshov <kuleshovmail@gmail.com>
Cc: Alexander Popov <alpopov@ptsecurity.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Cc: Baoquan He <bhe@redhat.com>
Cc: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Borislav Petkov <bp@suse.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Christian Borntraeger <borntraeger@de.ibm.com>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Dave Young <dyoung@redhat.com>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Jan Beulich <JBeulich@suse.com>
Cc: Joerg Roedel <jroedel@suse.de>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Juergen Gross <jgross@suse.com>
Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Lv Zheng <lv.zheng@intel.com>
Cc: Mark Salter <msalter@redhat.com>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Matt Fleming <matt@codeblueprint.co.uk>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephen Smalley <sds@tycho.nsa.gov>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Toshi Kani <toshi.kani@hpe.com>
Cc: Xiao Guangrong <guangrong.xiao@linux.intel.com>
Cc: Yinghai Lu <yinghai@kernel.org>
Cc: kernel-hardening@lists.openwall.com
Cc: linux-doc@vger.kernel.org
Link: http://lkml.kernel.org/r/1466556426-32664-7-git-send-email-keescook@chromium.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2016-07-08 17:35:15 +02:00
Thomas Garnier
d899a7d146 x86/mm: Refactor KASLR entropy functions
Move the KASLR entropy functions into arch/x86/lib to be used in early
kernel boot for KASLR memory randomization.

Signed-off-by: Thomas Garnier <thgarnie@google.com>
Signed-off-by: Kees Cook <keescook@chromium.org>
Cc: Alexander Kuleshov <kuleshovmail@gmail.com>
Cc: Alexander Popov <alpopov@ptsecurity.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Cc: Baoquan He <bhe@redhat.com>
Cc: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Borislav Petkov <bp@suse.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Christian Borntraeger <borntraeger@de.ibm.com>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Dave Young <dyoung@redhat.com>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Jan Beulich <JBeulich@suse.com>
Cc: Joerg Roedel <jroedel@suse.de>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Juergen Gross <jgross@suse.com>
Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Lv Zheng <lv.zheng@intel.com>
Cc: Mark Salter <msalter@redhat.com>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Matt Fleming <matt@codeblueprint.co.uk>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephen Smalley <sds@tycho.nsa.gov>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Toshi Kani <toshi.kani@hpe.com>
Cc: Xiao Guangrong <guangrong.xiao@linux.intel.com>
Cc: Yinghai Lu <yinghai@kernel.org>
Cc: kernel-hardening@lists.openwall.com
Cc: linux-doc@vger.kernel.org
Link: http://lkml.kernel.org/r/1466556426-32664-2-git-send-email-keescook@chromium.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2016-07-08 17:33:45 +02:00
Baoquan He
6daa2ec0b3 x86/KASLR: Fix boot crash with certain memory configurations
Ye Xiaolong reported this boot crash:

|
|  XZ-compressed data is corrupt
|
|   -- System halted
|

Fix the bug in mem_avoid_overlap() of finding the earliest overlap.

Reported-and-tested-by: Ye Xiaolong <xiaolong.ye@intel.com>
Signed-off-by: Baoquan He <bhe@redhat.com>
Cc: Kees Cook <keescook@chromium.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2016-07-08 14:36:19 +02:00
Colin Ian King
f6d1747f89 x86/efi: Remove unused variable 'efi'
Remove unused variable 'efi', it is never used. This fixes the following
clang build warning:

  arch/x86/boot/compressed/eboot.c:803:2: warning: Value stored to 'efi' is never read

Signed-off-by: Colin Ian King <colin.king@canonical.com>
Signed-off-by: Matt Fleming <matt@codeblueprint.co.uk>
Cc: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-efi@vger.kernel.org
Link: http://lkml.kernel.org/r/1466839230-12781-4-git-send-email-matt@codeblueprint.co.uk
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2016-06-27 13:06:55 +02:00
Yinghai Lu
e066cc4777 x86/KASLR: Allow randomization below the load address
Currently the kernel image physical address randomization's lower
boundary is the original kernel load address.

For bootloaders that load kernels into very high memory (e.g. kexec),
this means randomization takes place in a very small window at the
top of memory, ignoring the large region of physical memory below
the load address.

Since mem_avoid[] is already correctly tracking the regions that must be
avoided, this patch changes the minimum address to whatever is less:
512M (to conservatively avoid unknown things in lower memory) or the
load address. Now, for example, if the kernel is loaded at 8G, [512M,
8G) will be added to the list of possible physical memory positions.

Signed-off-by: Yinghai Lu <yinghai@kernel.org>
[ Rewrote the changelog, refactored the code to use min(). ]
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>
Link: http://lkml.kernel.org/r/1464216334-17200-6-git-send-email-keescook@chromium.org
[ Edited the changelog some more, plus the code comment as well. ]
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2016-06-26 12:32:05 +02:00
Kees Cook
ed9f007ee6 x86/KASLR: Extend kernel image physical address randomization to addresses larger than 4G
We want the physical address to be randomized anywhere between
16MB and the top of physical memory (up to 64TB).

This patch exchanges the prior slots[] array for the new slot_areas[]
array, and lifts the limitation of KERNEL_IMAGE_SIZE on the physical
address offset for 64-bit. As before, process_e820_entry() walks
memory and populates slot_areas[], splitting on any detected mem_avoid
collisions.

Finally, since the slots[] array and its associated functions are not
needed any more, so they are removed.

Based on earlier patches by Baoquan He.

Originally-from: 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: 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/1464216334-17200-5-git-send-email-keescook@chromium.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2016-06-26 12:32:05 +02:00
Baoquan He
8391c73c96 x86/KASLR: Randomize virtual address separately
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>
2016-06-26 12:32:04 +02:00
Kees Cook
11fdf97a3c x86/KASLR: Clarify identity map interface
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>
2016-06-26 12:32:04 +02:00
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
Kees Cook
65fe935dd2 x86/KASLR, x86/power: Remove x86 hibernation restrictions
With the following fix:

  70595b479ce1 ("x86/power/64: Fix crash whan the hibernation code passes control to the image kernel")

... there is no longer a problem with hibernation resuming a
KASLR-booted kernel image, so remove the restriction.

Signed-off-by: Kees Cook <keescook@chromium.org>
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: H. Peter Anvin <hpa@zytor.com>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Len Brown <len.brown@intel.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Linux PM list <linux-pm@vger.kernel.org>
Cc: Logan Gunthorpe <logang@deltatee.com>
Cc: Pavel Machek <pavel@ucw.cz>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephen Smalley <sds@tycho.nsa.gov>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Yinghai Lu <yinghai@kernel.org>
Cc: linux-doc@vger.kernel.org
Link: http://lkml.kernel.org/r/20160613221002.GA29719@www.outflux.net
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2016-06-26 12:32:03 +02:00
Ingo Molnar
50c0587eed Merge branch 'linus' into x86/asm, to pick up fixes
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2016-06-11 11:25:50 +02:00
H. Peter Anvin
66928b4eb9 x86, asm, boot: Use CC_SET()/CC_OUT() in arch/x86/boot/boot.h
Remove open-coded uses of set instructions to use CC_SET()/CC_OUT() in
arch/x86/boot/boot.h.

Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
Link: http://lkml.kernel.org/r/1465414726-197858-10-git-send-email-hpa@linux.intel.com
Reviewed-by: Andy Lutomirski <luto@kernel.org>
Reviewed-by: Borislav Petkov <bp@suse.de>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
2016-06-08 12:41:20 -07:00
H. Peter Anvin
117780eef7 x86, asm: use bool for bitops and other assembly outputs
The gcc people have confirmed that using "bool" when combined with
inline assembly always is treated as a byte-sized operand that can be
assumed to be 0 or 1, which is exactly what the SET instruction
emits.  Change the output types and intermediate variables of as many
operations as practical to "bool".

Signed-off-by: H. Peter Anvin <hpa@zytor.com>
Link: http://lkml.kernel.org/r/1465414726-197858-3-git-send-email-hpa@linux.intel.com
Reviewed-by: Andy Lutomirski <luto@kernel.org>
Reviewed-by: Borislav Petkov <bp@suse.de>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
2016-06-08 12:41:20 -07:00
H. Peter Anvin
9c77679cad x86, build: copy ldlinux.c32 to image.iso
For newer versions of Syslinux, we need ldlinux.c32 in addition to
isolinux.bin to reside on the boot disk, so if the latter is found,
copy it, too, to the isoimage tree.

Signed-off-by: H. Peter Anvin <hpa@zytor.com>
Cc: Linux Stable Tree <stable@vger.kernel.org>
2016-06-07 15:54:18 -07:00
Linus Torvalds
5b26fc8824 Merge branch 'kbuild' of git://git.kernel.org/pub/scm/linux/kernel/git/mmarek/kbuild
Pull kbuild updates from Michal Marek:

 - new option CONFIG_TRIM_UNUSED_KSYMS which does a two-pass build and
   unexports symbols which are not used in the current config [Nicolas
   Pitre]

 - several kbuild rule cleanups [Masahiro Yamada]

 - warning option adjustments for gcov etc [Arnd Bergmann]

 - a few more small fixes

* 'kbuild' of git://git.kernel.org/pub/scm/linux/kernel/git/mmarek/kbuild: (31 commits)
  kbuild: move -Wunused-const-variable to W=1 warning level
  kbuild: fix if_change and friends to consider argument order
  kbuild: fix adjust_autoksyms.sh for modules that need only one symbol
  kbuild: fix ksym_dep_filter when multiple EXPORT_SYMBOL() on the same line
  gcov: disable -Wmaybe-uninitialized warning
  gcov: disable tree-loop-im to reduce stack usage
  gcov: disable for COMPILE_TEST
  Kbuild: disable 'maybe-uninitialized' warning for CONFIG_PROFILE_ALL_BRANCHES
  Kbuild: change CC_OPTIMIZE_FOR_SIZE definition
  kbuild: forbid kernel directory to contain spaces and colons
  kbuild: adjust ksym_dep_filter for some cmd_* renames
  kbuild: Fix dependencies for final vmlinux link
  kbuild: better abstract vmlinux sequential prerequisites
  kbuild: fix call to adjust_autoksyms.sh when output directory specified
  kbuild: Get rid of KBUILD_STR
  kbuild: rename cmd_as_s_S to cmd_cpp_s_S
  kbuild: rename cmd_cc_i_c to cmd_cpp_i_c
  kbuild: drop redundant "PHONY += FORCE"
  kbuild: delete unnecessary "@:"
  kbuild: mark help target as PHONY
  ...
2016-05-26 22:01:22 -07:00
Linus Torvalds
9a45f036af Merge branch 'x86-boot-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull x86 boot updates from Ingo Molnar:
 "The biggest changes in this cycle were:

   - prepare for more KASLR related changes, by restructuring, cleaning
     up and fixing the existing boot code.  (Kees Cook, Baoquan He,
     Yinghai Lu)

   - simplifly/concentrate subarch handling code, eliminate
     paravirt_enabled() usage.  (Luis R Rodriguez)"

* 'x86-boot-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (50 commits)
  x86/KASLR: Clarify purpose of each get_random_long()
  x86/KASLR: Add virtual address choosing function
  x86/KASLR: Return earliest overlap when avoiding regions
  x86/KASLR: Add 'struct slot_area' to manage random_addr slots
  x86/boot: Add missing file header comments
  x86/KASLR: Initialize mapping_info every time
  x86/boot: Comment what finalize_identity_maps() does
  x86/KASLR: Build identity mappings on demand
  x86/boot: Split out kernel_ident_mapping_init()
  x86/boot: Clean up indenting for asm/boot.h
  x86/KASLR: Improve comments around the mem_avoid[] logic
  x86/boot: Simplify pointer casting in choose_random_location()
  x86/KASLR: Consolidate mem_avoid[] entries
  x86/boot: Clean up pointer casting
  x86/boot: Warn on future overlapping memcpy() use
  x86/boot: Extract error reporting functions
  x86/boot: Correctly bounds-check relocations
  x86/KASLR: Clean up unused code from old 'run_size' and rename it to 'kernel_total_size'
  x86/boot: Fix "run_size" calculation
  x86/boot: Calculate decompression size during boot not build
  ...
2016-05-16 15:54:01 -07:00
Kees Cook
d2d3462f9f x86/KASLR: Clarify purpose of each get_random_long()
KASLR will be calling get_random_long() twice, but the debug output
won't distinguishing between them. This patch adds a report on when it
is fetching the physical vs virtual address. With this, once the virtual
offset is separate, the report changes from:

 KASLR using RDTSC...
 KASLR using RDTSC...

into:

 Physical KASLR using RDTSC...
 Virtual KASLR using RDTSC...

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: 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/1462825332-10505-7-git-send-email-keescook@chromium.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2016-05-10 10:12:08 +02:00
Baoquan He
071a74930e x86/KASLR: Add virtual address choosing function
To support randomizing the kernel virtual address separately from the
physical address, this patch adds find_random_virt_addr() to choose
a slot anywhere between LOAD_PHYSICAL_ADDR and KERNEL_IMAGE_SIZE.
Since this address is virtual, not physical, we can place the kernel
anywhere in this region, as long as it is aligned and (in the case of
kernel being larger than the slot size) placed with enough room to load
the entire kernel image.

For clarity and readability, find_random_addr() is renamed to
find_random_phys_addr() and has "size" renamed to "image_size" to match
find_random_virt_addr().

Signed-off-by: Baoquan He <bhe@redhat.com>
[ Rewrote changelog, refactored slot calculation for readability. ]
[ Renamed find_random_phys_addr() and size argument. ]
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: 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: 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/1462825332-10505-6-git-send-email-keescook@chromium.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2016-05-10 10:12:06 +02:00
Kees Cook
06486d6c97 x86/KASLR: Return earliest overlap when avoiding regions
In preparation for being able to detect where to split up contiguous
memory regions that overlap with memory regions to avoid, we need to
pass back what the earliest overlapping region was. This modifies the
overlap checker to return that information.

Based on a separate mem_min_overlap() implementation by 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: 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/1462825332-10505-5-git-send-email-keescook@chromium.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2016-05-10 10:12:04 +02:00
Baoquan He
c401cf1524 x86/KASLR: Add 'struct slot_area' to manage random_addr slots
In order to support KASLR moving the kernel anywhere in physical memory
(which could be up to 64TB), we need to handle counting the potential
randomization locations in a more efficient manner.

In the worst case with 64TB, there could be roughly 32 * 1024 * 1024
randomization slots if CONFIG_PHYSICAL_ALIGN is 0x1000000. Currently
the starting address of candidate positions is stored into the slots[]
array, one at a time. This method would cost too much memory and it's
also very inefficient to get and save the slot information into the slot
array one by one.

This patch introduces 'struct slot_area' to manage each contiguous region
of randomization slots. Each slot_area will contain the starting address
and how many available slots are in this area. As with the original code,
the slot_areas[] will avoid the mem_avoid[] regions.

Since setup_data is a linked list, it could contain an unknown number
of memory regions to be avoided, which could cause us to fragment
the contiguous memory that the slot_area array is tracking. In normal
operation this level of fragmentation will be extremely rare, but we
choose a suitably large value (100) for the array. If setup_data forces
the slot_area array to become highly fragmented and there are more
slots available beyond the first 100 found, the rest will be ignored
for KASLR selection.

The function store_slot_info() is used to calculate the number of slots
available in the passed-in memory region and stores it into slot_areas[]
after adjusting for alignment and size requirements.

Signed-off-by: Baoquan He <bhe@redhat.com>
[ Rewrote changelog, squashed with new functions. ]
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: 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: 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/1462825332-10505-4-git-send-email-keescook@chromium.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2016-05-10 10:12:04 +02:00
Kees Cook
cb18ef0da2 x86/boot: Add missing file header comments
There were some files with missing header comments. Since they are
included from both compressed and regular kernels, make note of that.
Also corrects a typo in the mem_avoid comments.

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: 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/1462825332-10505-3-git-send-email-keescook@chromium.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2016-05-10 10:12:03 +02:00
Kees Cook
434a6c9f90 x86/KASLR: Initialize mapping_info every time
As it turns out, mapping_info DOES need to be initialized every
time, because pgt_data address could be changed during kernel
relocation. So it can not be build time assigned.

Without this, page tables were not being corrected updated, which
could cause reboots when a physical address beyond 2G was chosen.

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: 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/1462825332-10505-2-git-send-email-keescook@chromium.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2016-05-10 10:12:02 +02:00
Borislav Petkov
36a39ac967 x86/boot: Comment what finalize_identity_maps() does
So it is not really obvious that finalize_identity_maps() doesn't do any
finalization but it *actually* writes CR3 with the ident PGD. Comment
that at the call site.

Signed-off-by: Borislav Petkov <bp@suse.de>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Kees Cook <keescook@chromium.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: akpm@linux-foundation.org
Cc: bhe@redhat.com
Cc: dyoung@redhat.com
Cc: jkosina@suse.cz
Cc: linux-tip-commits@vger.kernel.org
Cc: luto@kernel.org
Cc: vgoyal@redhat.com
Cc: yinghai@kernel.org
Link: http://lkml.kernel.org/r/20160507100541.GA24613@pd.tnic
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2016-05-10 10:12:02 +02:00
Kees Cook
3a94707d7a x86/KASLR: Build identity mappings on demand
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>
2016-05-07 07:38:39 +02:00
Kees Cook
ed09acde44 x86/KASLR: Improve comments around the mem_avoid[] logic
This attempts to improve the comments that describe how the memory
range used for decompression is avoided. Additionally uses an enum
instead of raw numbers for the mem_avoid[] indexing.

Suggested-by: Borislav Petkov <bp@alien8.de>
Signed-off-by: Kees Cook <keescook@chromium.org>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Baoquan He <bhe@redhat.com>
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: 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/20160506194459.GA16480@www.outflux.net
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2016-05-07 07:38:38 +02:00