The PE/COFF headers currently describe only the initialised-data
portions of the image, and result in no space being allocated for the
uninitialised-data portions. Consequently, the EFI boot stub will end
up overwriting unexpected areas of memory, with unpredictable results.
Fix by including a .bss section in the PE/COFF headers (functionally
equivalent to the init_size field in the bzImage header).
Signed-off-by: Michael Brown <mbrown@fensystems.co.uk>
Cc: Thomas Bächler <thomas@archlinux.org>
Cc: Josh Boyer <jwboyer@fedoraproject.org>
Cc: <stable@vger.kernel.org>
Signed-off-by: Matt Fleming <matt.fleming@intel.com>
The kbuild test robot reported the following errors that were introduced
with commit 993c30a04e ("x86, tools: Consolidate #ifdef code"),
arch/x86/boot/tools/build.c: In function 'update_pecoff_setup_and_reloc':
>> arch/x86/boot/tools/build.c:252:1: error: parameter name omitted
static inline void update_pecoff_setup_and_reloc(unsigned int) {}
^
arch/x86/boot/tools/build.c: In function 'update_pecoff_text':
>> arch/x86/boot/tools/build.c:253:1: error: parameter name omitted
static inline void update_pecoff_text(unsigned int, unsigned int) {}
^
>> arch/x86/boot/tools/build.c:253:1: error: parameter name omitted
arch/x86/boot/tools/build.c: In function 'main':
>> arch/x86/boot/tools/build.c:372:2: warning: implicit declaration of function 'efi_stub_entry_update' [-Wimplicit-function-declaration]
efi_stub_entry_update();
^
Signed-off-by: Matt Fleming <matt.fleming@intel.com>
The EFI handover code only works if the "bitness" of the firmware and
the kernel match, i.e. 64-bit firmware and 64-bit kernel - it is not
possible to mix the two. This goes against the tradition that a 32-bit
kernel can be loaded on a 64-bit BIOS platform without having to do
anything special in the boot loader. Linux distributions, for one thing,
regularly run only 32-bit kernels on their live media.
Despite having only one 'handover_offset' field in the kernel header,
EFI boot loaders use two separate entry points to enter the kernel based
on the architecture the boot loader was compiled for,
(1) 32-bit loader: handover_offset
(2) 64-bit loader: handover_offset + 512
Since we already have two entry points, we can leverage them to infer
the bitness of the firmware we're running on, without requiring any boot
loader modifications, by making (1) and (2) valid entry points for both
CONFIG_X86_32 and CONFIG_X86_64 kernels.
To be clear, a 32-bit boot loader will always use (1) and a 64-bit boot
loader will always use (2). It's just that, if a single kernel image
supports (1) and (2) that image can be used with both 32-bit and 64-bit
boot loaders, and hence both 32-bit and 64-bit EFI.
(1) and (2) must be 512 bytes apart at all times, but that is already
part of the boot ABI and we could never change that delta without
breaking existing boot loaders anyhow.
Signed-off-by: Matt Fleming <matt.fleming@intel.com>
Instead of littering main() with #ifdef CONFIG_EFI_STUB, move the logic
into separate functions that do nothing if the config option isn't set.
This makes main() much easier to read.
Acked-by: Borislav Petkov <bp@suse.de>
Signed-off-by: Matt Fleming <matt.fleming@intel.com>
When building on x86, the final image building step always emits stats
to stderr, even though this information is neither a warning nor an error:
BUILD arch/x86/boot/bzImage
Setup is 16188 bytes (padded to 16384 bytes).
System is 6368 kB
CRC cbe50c61
Validating automated builds would be cleaner if stderr did not have to
filter out these lines. Instead, change how tools/build is called, and
make the zoffset header unconditional, and write to a specified file
instead of to stdout, which can then be used for statistics, leaving
stderr open for legitimate warnings and errors, like the output from
die().
Signed-off-by: Kees Cook <keescook@chromium.org>
Link: http://lkml.kernel.org/r/20130906181532.GA31260@www.outflux.net
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
We have historically hard-coded entry points in head.S just so it's easy
to build the executable/bzImage headers with references to them.
Unfortunately, this leads to boot loaders abusing these "known" addresses
even when they are *explicitly* told that they "should look at the ELF
header to find this address, as it may change in the future". And even
when the address in question *has* actually been changed in the past,
without fanfare or thought to compatibility.
Thus we have bootloaders doing stunningly broken things like jumping
to offset 0x200 in the kernel startup code in 64-bit mode, *hoping*
that startup_64 is still there (it has moved at least once
before). And hoping that it's actually a 64-bit kernel despite the
fact that we don't give them any indication of that fact.
This patch should hopefully remove the temptation to abuse internal
addresses in future, where sternly worded comments have not sufficed.
Instead of having hard-coded addresses and saying "please don't abuse
these", we actually pull the addresses out of the ELF payload into
zoffset.h, and make build.c shove them back into the right places in
the bzImage header.
Rather than including zoffset.h into build.c and thus having to rebuild
the tool for every kernel build, we parse it instead. The parsing code
is small and simple.
This patch doesn't actually move any of the interesting entry points, so
any offending bootloader will still continue to "work" after this patch
is applied. For some version of "work" which includes jumping into the
compressed payload and crashing, if the bzImage it's given is a 32-bit
kernel. No change there then.
[ hpa: some of the issues in the description are addressed or
retconned by the 2.12 boot protocol. This patch has been edited to
only remove fixed addresses that were *not* thus retconned. ]
Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>
Link: http://lkml.kernel.org/r/1358513837.2397.247.camel@shinybook.infradead.org
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
Cc: Matt Fleming <matt.fleming@intel.com>
Some UEFI firmware will not load a .efi with a .reloc section
with a size of 0.
Therefore, we create a .efi image with 4 main areas and 3 sections.
1. PE/COFF file header
2. .setup section (covers all setup code following the first sector)
3. .reloc section (contains 1 dummy reloc entry, created in build.c)
4. .text section (covers the remaining kernel image)
To make room for the new .setup section data, the header
bugger_off_msg had to be shortened.
Reported-by: Henrik Rydberg <rydberg@euromail.se>
Signed-off-by: Jordan Justen <jordan.l.justen@intel.com>
Link: http://lkml.kernel.org/r/1339085121-12760-1-git-send-email-jordan.l.justen@intel.com
Tested-by: Lee G Rosenbaum <lee.g.rosenbaum@intel.com>
Tested-by: Henrik Rydberg <rydberg@euromail.se>
Cc: Matt Fleming <matt.fleming@intel.com>
Signed-off-by: H. Peter Anvin <hpa@zytor.com>
Pull x86 EFI updates from Ingo Molnar:
"This patchset makes changes to the bzImage EFI header, so that it can
be signed with a secure boot signature tool. It should not affect
anyone who is not using the EFI self-boot feature in any way."
* 'x86-efi-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
x86, efi: Fix NumberOfRvaAndSizes field in PE32 header for EFI_STUB
x86, efi: Fix .text section overlapping image header for EFI_STUB
x86, efi: Fix issue of overlapping .reloc section for EFI_STUB
The method used to work out whether we were booted by EFI firmware or
via a boot loader is broken. Because efi_main() is always executed
when booting from a boot loader we will dereference invalid pointers
either on the stack (CONFIG_X86_32) or contained in %rdx
(CONFIG_X86_64) when searching for an EFI System Table signature.
Instead of dereferencing these invalid system table pointers, add a
new entry point that is only used when booting from EFI firmware, when
we know the pointer arguments will be valid. With this change legacy
boot loaders will no longer execute efi_main(), but will instead skip
EFI stub initialisation completely.
[ hpa: Marking this for urgent/stable since it is a regression when
the option is enabled; without the option the patch has no effect ]
Signed-off-by: Matt Fleming <matt.hfleming@intel.com>
Link: http://lkml.kernel.org/r/1334584744.26997.14.camel@mfleming-mobl1.ger.corp.intel.com
Reported-by: Jordan Justen <jordan.l.justen@intel.com>
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
Cc: <stable@vger.kernel.org> v3.3
Reason for merge:
The updates to the EFI boot stub generation conflicted with the
changes to properly use the get/put_unaligned_le*() macros to
generate images.
This merge commit completes the conversion in
arch/x86/boot/tools/build.c including the places in the code
which had been changed on the x86/efi branch.
Resolved Conflicts:
arch/x86/boot/tools/build.c
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
This change modifes the PE .text section to start after
the first sector of the kernel image.
The header may be modified by the UEFI secure boot signing,
so it is not appropriate for it to be included in one of the
image sections. Since the sections are part of the secure
boot hash, this modification to the .text section contents
would invalidate the secure boot signed hash.
Note: UEFI secure boot does hash the image header, but
fields that are changed by the signing process are excluded
from the hash calculation. This exclusion process is only
handled for the image header, and not image sections.
Luckily, we can still easily boot without the first sector
by initializing a few fields in arch/x86/boot/compressed/eboot.c.
Signed-off-by: Matt Fleming <matt.fleming@intel.com>
Link: http://lkml.kernel.org/r/1332520506-6472-3-git-send-email-jordan.l.justen@intel.com
[jordan.l.justen@intel.com: set .text vma & file offset]
Signed-off-by: Jordan Justen <jordan.l.justen@intel.com>
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
It would appear that we never actually generated a correct CRC when
building on a bigendian machine. Depending on the word size, we would
either generate an all-zero CRC (64-bit machine) or a byte-swapped
CRC (32-bit machine.) Fix the types used so we don't arbitrarily use
a 64-bit word to hold 32-bit numbers, and pass the CRC through
put_unaligned_le32() like all the other numbers.
Signed-off-by: H. Peter Anvin <hpa@zytor.com>
Cc: Stephen Rothwell <sfr@canb.auug.org.au>
Cc: Matt Fleming <matt@console-pimps.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Nick Bowler <nbowler@elliptictech.com>
Link: http://lkml.kernel.org/r/20120229111322.9eb4b23ff1672e8853ad3b3b@canb.auug.org.au
We include <sys/sysmacros.h> and <asm/boot.h>, but none of those
header files actually provide anything this file needs. Furthermore,
it breaks cross-compilation, so just remove them.
Reported-by: Stephen Rothwell <sfr@canb.auug.org.au>
Reported-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: H. Peter Anvin <hpa@zytor.com>
Cc: Matt Fleming <matt@console-pimps.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Nick Bowler <nbowler@elliptictech.com>
Link: http://lkml.kernel.org/r/20120229111322.9eb4b23ff1672e8853ad3b3b@canb.auug.org.au
We may need to convert the endianness of the data we read from/write
to 'buf', so let's use {get,put}_unaligned_le32() to do that. Failure
to do so can result in accessing invalid memory, leading to a
segfault. Stephen Rothwell noticed this bug while cross-building an
x86_64 allmodconfig kernel on PowerPC.
We need to read from and write to 'buf' a byte at a time otherwise
it's possible we'll perform an unaligned access, which can lead to bus
errors when cross-building an x86 kernel on risc architectures.
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Nick Bowler <nbowler@elliptictech.com>
Tested-by: Stephen Rothwell <sfr@canb.auug.org.au>
Reported-by: Stephen Rothwell <sfr@canb.auug.org.au>
Signed-off-by: Matt Fleming <matt.fleming@intel.com>
Link: http://lkml.kernel.org/r/1330436245-24875-6-git-send-email-matt@console-pimps.org
Signed-off-by: H. Peter Anvin <hpa@zytor.com>
There is currently a large divide between kernel development and the
development of EFI boot loaders. The idea behind this patch is to give
the kernel developers full control over the EFI boot process. As
H. Peter Anvin put it,
"The 'kernel carries its own stub' approach been very successful in
dealing with BIOS, and would make a lot of sense to me for EFI as
well."
This patch introduces an EFI boot stub that allows an x86 bzImage to
be loaded and executed by EFI firmware. The bzImage appears to the
firmware as an EFI application. Luckily there are enough free bits
within the bzImage header so that it can masquerade as an EFI
application, thereby coercing the EFI firmware into loading it and
jumping to its entry point. The beauty of this masquerading approach
is that both BIOS and EFI boot loaders can still load and run the same
bzImage, thereby allowing a single kernel image to work in any boot
environment.
The EFI boot stub supports multiple initrds, but they must exist on
the same partition as the bzImage. Command-line arguments for the
kernel can be appended after the bzImage name when run from the EFI
shell, e.g.
Shell> bzImage console=ttyS0 root=/dev/sdb initrd=initrd.img
v7:
- Fix checkpatch warnings.
v6:
- Try to allocate initrd memory just below hdr->inird_addr_max.
v5:
- load_options_size is UTF-16, which needs dividing by 2 to convert
to the corresponding ASCII size.
v4:
- Don't read more than image->load_options_size
v3:
- Fix following warnings when compiling CONFIG_EFI_STUB=n
arch/x86/boot/tools/build.c: In function ‘main’:
arch/x86/boot/tools/build.c:138:24: warning: unused variable ‘pe_header’
arch/x86/boot/tools/build.c:138:15: warning: unused variable ‘file_sz’
- As reported by Matthew Garrett, some Apple machines have GOPs that
don't have hardware attached. We need to weed these out by
searching for ones that handle the PCIIO protocol.
- Don't allocate memory if no initrds are on cmdline
- Don't trust image->load_options_size
Maarten Lankhorst noted:
- Don't strip first argument when booted from efibootmgr
- Don't allocate too much memory for cmdline
- Don't update cmdline_size, the kernel considers it read-only
- Don't accept '\n' for initrd names
v2:
- File alignment was too large, was 8192 should be 512. Reported by
Maarten Lankhorst on LKML.
- Added UGA support for graphics
- Use VIDEO_TYPE_EFI instead of hard-coded number.
- Move linelength assignment until after we've assigned depth
- Dynamically fill out AddressOfEntryPoint in tools/build.c
- Don't use magic number for GDT/TSS stuff. Requested by Andi Kleen
- The bzImage may need to be relocated as it may have been loaded at
a high address address by the firmware. This was required to get my
macbook booting because the firmware loaded it at 0x7cxxxxxx, which
triggers this error in decompress_kernel(),
if (heap > ((-__PAGE_OFFSET-(128<<20)-1) & 0x7fffffff))
error("Destination address too large");
Cc: Mike Waychison <mikew@google.com>
Cc: Matthew Garrett <mjg@redhat.com>
Tested-by: Henrik Rydberg <rydberg@euromail.se>
Signed-off-by: Matt Fleming <matt.fleming@intel.com>
Link: http://lkml.kernel.org/r/1321383097.2657.9.camel@mfleming-mobl1.ger.corp.intel.com
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
This has been obsoleted by the root= commandline and the rdev utility
for many, many years. People who still depend on this will surely
have a copy of the rdev utility around, the rest of the world gets rid
of another piece of buildhost-dependent data in the build. Thanks to
Paul Bolle for the build.c cleanup.
Cc: Paul Bolle <pebolle@tiscali.nl>
Signed-off-by: Michal Marek <mmarek@suse.cz>
Link: http://lkml.kernel.org/r/1302607824-24699-1-git-send-email-mmarek@suse.cz
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
Impact: obsolete feature removal
The zImage kernel format has been functionally unused for a very long
time. It is just barely possible to build a modern kernel that still
fits within the zImage size limit, but it is highly unlikely that
anyone ever uses it. Furthermore, although it is still supported by
most bootloaders, it has been at best poorly tested (or not tested at
all); some bootloaders are even known to not support zImage at all and
not having even noticed.
Also remove some really obsolete constants that no longer have any
meaning.
LKML-Reference: <49B703D4.1000008@zytor.com>
Signed-off-by: H. Peter Anvin <hpa@zytor.com>
Michael Brown