Commit Graph
47 Commits
Author SHA1 Message Date
Daniel Kiper 8b3a95655b util/grub-install: Fix NULL pointer dereferences
Two grub_device_open() calls does not have associated NULL checks
for returned values. Fix that and appease the Coverity.

Fixes: CID 314583

Signed-off-by: Daniel Kiper <daniel.kiper@oracle.com>
Reviewed-by: Javier Martinez Canillas <javierm@redhat.com>
2021-03-02 15:54:17 +01:00
Daniel Kiper a195dbb677 loader/linux: Report the UEFI Secure Boot status to the Linux kernel
Now that the GRUB has a grub_efi_get_secureboot() function to check the
UEFI Secure Boot status, use it to report that to the Linux kernel.

Signed-off-by: Ignat Korchagin <ignat@cloudflare.com>
Signed-off-by: Daniel Kiper <daniel.kiper@oracle.com>
Signed-off-by: Marco A Benatto <mbenatto@redhat.com>
Signed-off-by: Javier Martinez Canillas <javierm@redhat.com>
Reviewed-by: Daniel Kiper <daniel.kiper@oracle.com>
2020-12-12 01:19:03 +01:00
Daniel Kiper d7e54b2e5f efi: Add secure boot detection
Introduce grub_efi_get_secureboot() function which returns whether
UEFI Secure Boot is enabled or not on UEFI systems.

Signed-off-by: Ignat Korchagin <ignat@cloudflare.com>
Signed-off-by: Daniel Kiper <daniel.kiper@oracle.com>
Signed-off-by: Marco A Benatto <mbenatto@redhat.com>
Signed-off-by: Javier Martinez Canillas <javierm@redhat.com>
Reviewed-by: Daniel Kiper <daniel.kiper@oracle.com>
2020-12-11 13:56:22 +01:00
Daniel Kiper ac5c936754 efi: Add a function to read EFI variables with attributes
It will be used to properly detect and report UEFI Secure Boot status to
the x86 Linux kernel. The functionality will be added by subsequent patches.

Signed-off-by: Ignat Korchagin <ignat@cloudflare.com>
Signed-off-by: Daniel Kiper <daniel.kiper@oracle.com>
Signed-off-by: Marco A Benatto <mbenatto@redhat.com>
Signed-off-by: Javier Martinez Canillas <javierm@redhat.com>
Reviewed-by: Daniel Kiper <daniel.kiper@oracle.com>
2020-12-11 13:55:31 +01:00
Daniel Kiper 04ae030d0e efi: Return grub_efi_status_t from grub_efi_get_variable()
This is needed to properly detect and report UEFI Secure Boot status
to the x86 Linux kernel. The functionality will be added by subsequent
patches.

Signed-off-by: Daniel Kiper <daniel.kiper@oracle.com>
Signed-off-by: Marco A Benatto <mbenatto@redhat.com>
Signed-off-by: Javier Martinez Canillas <javierm@redhat.com>
Reviewed-by: Daniel Kiper <daniel.kiper@oracle.com>
2020-12-11 13:54:54 +01:00
Daniel Kiper f76a27996c efi: Make shim_lock GUID and protocol type public
The GUID will be used to properly detect and report UEFI Secure Boot
status to the x86 Linux kernel. The functionality will be added by
subsequent patches. The shim_lock protocol type is made public for
completeness.

Additionally, fix formatting of four preceding GUIDs.

Signed-off-by: Daniel Kiper <daniel.kiper@oracle.com>
Signed-off-by: Marco A Benatto <mbenatto@redhat.com>
Signed-off-by: Javier Martinez Canillas <javierm@redhat.com>
Reviewed-by: Daniel Kiper <daniel.kiper@oracle.com>
2020-12-11 13:54:23 +01:00
Daniel Kiper 1e81bf6d2d efi/tpm: Fix typo in grub_efi_tpm2_protocol struct
Rename get_active_pcr_blanks() to get_active_pcr_banks().

Signed-off-by: Daniel Kiper <daniel.kiper@oracle.com>
Reviewed-by: Javier Martinez Canillas <javierm@redhat.com>
2020-09-18 21:23:21 +02:00
Daniel Kiper c386331364 i386/efi/init: Drop bogus include
Signed-off-by: Daniel Kiper <daniel.kiper@oracle.com>
Reviewed-by: Javier Martinez Canillas <javierm@redhat.com>
2020-09-18 21:22:32 +02:00
Daniel Kiper 30c4e3ca40 docs: Fix devicetree command description
Specifically fix the subsection and drop bogus reference to the GNU/Linux.

Reported-by: Patrick Higgins <higgi1pt@gmail.com>
Signed-off-by: Daniel Kiper <daniel.kiper@oracle.com>
Reviewed-by: Javier Martinez Canillas <javierm@redhat.com>
2020-09-18 21:20:43 +02:00
Daniel Kiper 098058752e efi/chainloader: Propagate errors from copy_file_path()
Without any error propagated to the caller, make_file_path()
would then try to advance the invalid device path node with
GRUB_EFI_NEXT_DEVICE_PATH(), which would fail, returning a NULL
pointer that would subsequently be dereferenced. Hence, propagate
errors from copy_file_path().

Signed-off-by: Chris Coulson <chris.coulson@canonical.com>
Reviewed-by: Daniel Kiper <daniel.kiper@oracle.com>
2020-07-29 16:55:48 +02:00
Daniel Kiper 89f3da1a3d font: Do not load more than one NAME section
The GRUB font file can have one NAME section only. Though if somebody
crafts a broken font file with many NAME sections and loads it then the
GRUB leaks memory. So, prevent against that by loading first NAME
section and failing in controlled way on following one.

Reported-by: Chris Coulson <chris.coulson@canonical.com>
Signed-off-by: Daniel Kiper <daniel.kiper@oracle.com>
Reviewed-by: Jan Setje-Eilers <jan.setjeeilers@oracle.com>
2020-07-29 16:55:48 +02:00
Daniel Kiper 15d76540a7 INSTALL/configure: Update install doc and configure comment
..to reflect the GRUB build reality in them.

Additionally, fix text formatting a bit.

Signed-off-by: Daniel Kiper <daniel.kiper@oracle.com>
Reviewed-by: Leif Lindholm <leif@nuviainc.com>
2020-05-25 14:49:53 +02:00
Daniel Kiper c894713836 configure: Set gnu99 C language standard by default
Commit d5a32255d (misc: Make grub_strtol() "end" pointers have safer
const qualifiers) introduced "restrict" keyword into some functions
definitions. This keyword was introduced in C99 standard. However, some
compilers by default may use C89 or something different. This behavior
leads to the breakage during builds when c89 or gnu89 is in force. So,
let's set gnu99 C language standard for all compilers by default. This
way a bit random build issue will be fixed and the GRUB source will be
build consistently regardless of type and version of the compiler.

It was decided to use gnu99 C language standard because it fixes the
issue mentioned above and also provides some useful extensions which are
used here and there in the GRUB source. Potentially we can use gnu11
too. However, this may reduce pool of older compilers which can be used
to build the GRUB. So, let's live with gnu99 until we discover that we
strongly require a feature from newer C standard.

The user is still able to override C language standard using relevant
*_CFLAGS variables.

Signed-off-by: Daniel Kiper <daniel.kiper@oracle.com>
Reviewed-by: Leif Lindholm <leif@nuviainc.com>
2020-05-25 14:43:16 +02:00
Daniel Kiper f39f1ec5d9 autogen: Replace -iname with -ipath in find command
..because -iname cannot be used to match paths.

Signed-off-by: Daniel Kiper <daniel.kiper@oracle.com>
Reviewed-by: Javier Martinez Canillas <javierm@redhat.com>
Reviewed-by: Leif Lindholm <leif@nuviainc.com>
Reviewed-by: Daniel Axtens <dja@axtens.net>
2020-05-15 15:35:59 +02:00
Daniel Kiper f2d56dea9d INSTALL: Update configure example
..to make it more relevant.

Signed-off-by: Daniel Kiper <daniel.kiper@oracle.com>
Reviewed-by: Leif Lindholm <leif@nuviainc.com>
2020-05-15 15:34:43 +02:00
Daniel Kiper 4aa9614e0a configure: Drop unneeded TARGET_CFLAGS expansion
Signed-off-by: Daniel Kiper <daniel.kiper@oracle.com>
Reviewed-by: Javier Martinez Canillas <javierm@redhat.com>
Reviewed-by: Leif Lindholm <leif@nuviainc.com>
2020-05-15 15:33:08 +02:00
Daniel Kiper eb46ee98bc mips/cache: Add missing nop's in delay slots
Lack of them causes random instructions to be executed before the
jump really happens.

Signed-off-by: Vladimir Serbinenko <phcoder@google.com>
Reviewed-by: Daniel Kiper <daniel.kiper@oracle.com>
2020-05-15 14:30:07 +02:00
Daniel Kiper b53a2f2c66 loader/i386/linux: Fix an underflow in the setup_header length calculation
Recent work around x86 Linux kernel loader revealed an underflow in the
setup_header length calculation and another related issue. Both lead to
the memory overwrite and later machine crash.

Currently when the GRUB copies the setup_header into the linux_params
(struct boot_params, traditionally known as "zero page") it assumes the
setup_header size as sizeof(linux_i386_kernel_header/lh). This is
incorrect. It should use the value calculated accordingly to the Linux
kernel boot protocol. Otherwise in case of pretty old kernel, to be
exact Linux kernel boot protocol, the GRUB may write more into
linux_params than it was expected to. Fortunately this is not very big
issue. Though it has to be fixed. However, there is also an underflow
which is grave. It happens when

  sizeof(linux_i386_kernel_header/lh) > "real size of the setup_header".

Then len value wraps around and grub_file_read() reads whole kernel into
the linux_params overwriting memory past it. This leads to the GRUB
memory allocator breakage and finally to its crash during boot.

The patch fixes both issues. Additionally, it moves the code not related to
grub_memset(linux_params)/grub_memcpy(linux_params)/grub_file_read(linux_params)
section outside of it to not confuse the reader.

Fixes: e683cfb0cf (loader/i386/linux: Calculate the setup_header length)

Signed-off-by: Daniel Kiper <daniel.kiper@oracle.com>
Reviewed-by: Javier Martinez Canillas <javierm@redhat.com>
Reviewed-by: Ross Philipson <ross.philipson@oracle.com>
Reviewed-by: Krystian Hebel <krystian.hebel@3mdeb.com>
2019-12-20 20:35:21 +01:00
Daniel Kiper 26094f5241 Bump version to 2.05
Signed-off-by: Daniel Kiper <daniel.kiper@oracle.com>
2019-07-05 11:30:53 +02:00
Daniel Kiper 2a2e10c1b3 Release 2.04
Signed-off-by: Daniel Kiper <daniel.kiper@oracle.com>
2019-07-04 15:57:30 +02:00
Daniel Kiper acc726f812 x86/msr: Fix build with older GCC versions
Some older GCC versions produce following error when x86 MSR modules are build:

  In file included from commands/i386/rdmsr.c:29:0:
  ../include/grub/i386/rdmsr.h:27:29: error: no previous prototype for ‘grub_msr_read’ [-Werror=missing-prototypes]
   extern inline grub_uint64_t grub_msr_read (grub_uint32_t msr_id)
                               ^
  cc1: all warnings being treated as errors

This happens due to lack of support for a such usage of extern keyword
in older GCCs. Additionally, this usage is not consistent with the rest
of codebase. So, replace it with static keyword.

Additionally, fix incorrect coding style.

Reported-by: Eric Snowberg <eric.snowberg@oracle.com>
Reported-by: adrian15 <adrian15sgd@gmail.com>
Signed-off-by: Daniel Kiper <daniel.kiper@oracle.com>
Reviewed-by: Vladimir 'phcoder' Serbinenko <phcoder@gmail.com>
Reviewed-by: Eric Snowberg <eric.snowberg@oracle.com>
Tested-by: adrian15 <adrian15sgd@gmail.com>
2019-04-23 11:04:07 +02:00
Daniel Kiper fa20550f16 docs/grub-dev: Change comments rules
Current comments forms are annoying, so, some of them are disallowed
starting from now. New rules are more flexible and mostly aligned
with, e.g., Linux kernel comments rules.

Signed-off-by: Daniel Kiper <daniel.kiper@oracle.com>
Reviewed-by: Vladimir Serbinenko <phcoder@google.com>
2019-04-02 13:13:46 +02:00
Daniel Kiper 9dab2f51ea sparc: Enable __clzsi2() and __clzdi2()
This patch is similiar to commit e795b9011 (RISC-V: Add libgcc helpers
for clz) but for SPARC target.

Signed-off-by: Daniel Kiper <daniel.kiper@oracle.com>
Reviewed-by: Ross Philipson <ross.philipson@oracle.com>
2019-03-20 11:38:28 +01:00
Daniel Kiper e42b0d97ec mips: Enable __clzsi2()
This patch is similiar to commit e795b9011 (RISC-V: Add libgcc helpers
for clz) but for MIPS target.

Signed-off-by: Daniel Kiper <daniel.kiper@oracle.com>
Reviewed-by: Ross Philipson <ross.philipson@oracle.com>
2019-03-20 11:38:28 +01:00
Daniel Kiper c7bdb8273c verifiers: MIPS fallout cleanup
MIPS fallout cleanup after commit 4d4a8c96e (verifiers: Add possibility
to verify kernel and modules command lines).

Signed-off-by: Daniel Kiper <daniel.kiper@oracle.com>
Reviewed-by: Ross Philipson <ross.philipson@oracle.com>
2019-03-20 11:38:28 +01:00
Daniel Kiper ee025e512f verifiers: PowerPC fallout cleanup
PowerPC fallout cleanup after commit 4d4a8c96e (verifiers: Add possibility
to verify kernel and modules command lines) and ca0a4f689 (verifiers: File
type for fine-grained signature-verification controlling).

Signed-off-by: Daniel Kiper <daniel.kiper@oracle.com>
Reviewed-by: Ross Philipson <ross.philipson@oracle.com>
2019-03-20 11:38:28 +01:00
Daniel Kiper 1bc2b481c4 verifiers: IA-64 fallout cleanup
IA-64 fallout cleanup after commit 4d4a8c96e (verifiers: Add possibility
to verify kernel and modules command lines).

Signed-off-by: Daniel Kiper <daniel.kiper@oracle.com>
Reviewed-by: Ross Philipson <ross.philipson@oracle.com>
2019-03-20 11:38:28 +01:00
Daniel Kiper 718b3fb1dc Revert "grub-install: Check for arm-efi as a default target"
This reverts commit 082fd84d52.

Incorrect version of the patch was pushed into the git repo.

Reported-by: Leif Lindholm <leif.lindholm@linaro.org>
Signed-off-by: Daniel Kiper <daniel.kiper@oracle.com>
2019-02-26 15:07:28 +01:00
Daniel Kiper 95db97d041 verifiers: ARM Xen fallout cleanup
ARM Xen fallout cleanup after commit ca0a4f689 (verifiers: File type for
fine-grained signature-verification controlling).

Signed-off-by: Daniel Kiper <daniel.kiper@oracle.com>
Reviewed-by: Ross Philipson <ross.philipson@oracle.com>
2018-12-07 11:59:23 +01:00
Daniel Kiper e5b846333f verifiers: Xen fallout cleanup
Xen fallout cleanup after commit ca0a4f689 (verifiers: File type for
fine-grained signature-verification controlling).

Signed-off-by: Daniel Kiper <daniel.kiper@oracle.com>
Reviewed-by: Ross Philipson <ross.philipson@oracle.com>
2018-12-07 11:59:23 +01:00
Daniel Kiper 878398c1a3 efi: Add EFI shim lock verifier
This module provides shim lock verification for various kernels
if UEFI secure boot is enabled on a machine.

It is recommended to put this module into GRUB2 standalone image
(avoid putting iorw and memrw modules into it; they are disallowed
if UEFI secure boot is enabled). However, it is also possible to use
it as a normal module. Though such configurations are more fragile
and less secure due to various limitations.

If the module is loaded and UEFI secure boot is enabled then:
  - module itself cannot be unloaded (persistent module),
  - the iorw and memrw modules cannot be loaded,
  - if the iorw and memrw modules are loaded then
    machine boot is disabled,
  - GRUB2 defers modules and ACPI tables verification to
    other verifiers.

Signed-off-by: Daniel Kiper <daniel.kiper@oracle.com>
Reviewed-by: Ross Philipson <ross.philipson@oracle.com>
2018-11-09 13:25:31 +01:00
Daniel Kiper ee7808e219 dl: Add support for persistent modules
This type of modules cannot be unloaded. This is useful if a given
functionality, e.g. UEFI secure boot shim signature verification, should
not be disabled if it was enabled at some point in time. Somebody may
say that we can use standalone GRUB2 here. That is true. However, the
code is not so big nor complicated hence it make sense to support
modularized configs too.

Signed-off-by: Daniel Kiper <daniel.kiper@oracle.com>
Reviewed-by: Ross Philipson <ross.philipson@oracle.com>
2018-11-09 13:25:31 +01:00
Daniel Kiper b07feb8746 verifiers: Rename verify module to pgp module
Just for clarity. No functional change.

Signed-off-by: Daniel Kiper <daniel.kiper@oracle.com>
Reviewed-by: Ross Philipson <ross.philipson@oracle.com>
2018-11-09 13:25:31 +01:00
Daniel Kiper 5b8d535395 verifiers: Add possibility to defer verification to other verifiers
This way if a verifier requires verification of a given file it can defer task
to another verifier (another authority) if it is not able to do it itself. E.g.
shim_lock verifier, posted as a subsequent patch, is able to verify only PE
files. This means that it is not able to verify any of GRUB2 modules which have
to be trusted on UEFI systems with secure boot enabled. So, it can defer
verification to other verifier, e.g. PGP one.

I silently assume that other verifiers are trusted and will do good job for us.
Or at least they will not do any harm.

Signed-off-by: Daniel Kiper <daniel.kiper@oracle.com>
Reviewed-by: Ross Philipson <ross.philipson@oracle.com>
2018-11-09 13:25:31 +01:00
Daniel Kiper f3f8347569 bufio: Use grub_size_t instead of plain int for size
Signed-off-by: Vladimir Serbinenko <phcoder@gmail.com>
Signed-off-by: Daniel Kiper <daniel.kiper@oracle.com>
Reviewed-by: Ross Philipson <ross.philipson@oracle.com>
2018-11-09 13:25:31 +01:00
Daniel Kiper ba474d531a templates: Add missing "]"
Commit 51be337 (templates: Update grub script template files)
lacked one "]", so, add it.

Reported-by: Philip <philm@manjaro.org>
Signed-off-by: Daniel Kiper <daniel.kiper@oracle.com>
2018-06-05 13:04:04 +02:00
Daniel Kiper cda0a857dd xfs: Accept filesystem with sparse inodes
The sparse inode metadata format became a mkfs.xfs default in
xfsprogs-4.16.0, and such filesystems are now rejected by grub as
containing an incompatible feature.

In essence, this feature allows xfs to allocate inodes into fragmented
freespace.  (Without this feature, if xfs could not allocate contiguous
space for 64 new inodes, inode creation would fail.)

In practice, the disk format change is restricted to the inode btree,
which as far as I can tell is not used by grub.  If all you're doing
today is parsing a directory, reading an inode number, and converting
that inode number to a disk location, then ignoring this feature
should be fine, so I've added it to XFS_SB_FEAT_INCOMPAT_SUPPORTED

I did some brief testing of this patch by hacking up the regression
tests to completely fragment freespace on the test xfs filesystem, and
then write a large-ish number of inodes to consume any existing
contiguous 64-inode chunk.  This way any files the grub tests add and
traverse would be in such a fragmented inode allocation.  Tests passed,
but I'm not sure how to cleanly integrate that into the test harness.

Signed-off-by: Eric Sandeen <sandeen@redhat.com>
Reviewed-by: Daniel Kiper <daniel.kiper@oracle.com>
Tested-by: Chris Murphy <lists@colorremedies.com>
2018-05-29 16:16:02 +02:00
Daniel Kiper c422bb6019 ieee1275: no-data-command bus specific method
IEEE 1275-1994 Standard for Boot (Initialization Configuration)
Firmware: Core Requirements and Practices

E.3.2.2 Bus-specific methods for bus nodes

A package implementing the scsi-2 device type shall implement the
following bus-specific method:

no-data-command ( cmd-addr -- error? )
Executes a simple SCSI command, automatically retrying under
certain conditions.  cmd-addr is the address of a 6-byte command buffer
containing an SCSI command that does not have a data transfer phase.
Executes the command, retrying indefinitely with the same retry criteria
as retry-command.

error? is nonzero if an error occurred, zero otherwise.
NOTE no-data-command is a convenience function. It provides
no capabilities that are not present in retry-command, but for
those commands that meet its restrictions, it is easier to use.

Signed-off-by: Eric Snowberg <eric.snowberg@oracle.com>
Reviewed-by: Daniel Kiper <daniel.kiper@oracle.com>
2018-03-05 15:11:18 +01:00
Daniel Kiper ae2a274518 chainloader: Fix wrong break condition (must be AND not, OR)
The definition of bpb's num_total_sectors_16 and num_total_sectors_32
is that either the 16-bit field is non-zero and is used (in which case
eg mkfs.fat sets the 32-bit field to zero), or it is zero and the
32-bit field is used. Therefore, a BPB is invalid only if *both*
fields are zero; having one field as zero and the other as non-zero is
the case to be expected. (Indeed, according to Microsoft's specification
one of the fields *must* be zero, and the other non-zero.)

This affects all users of grub_chainloader_patch_bpb which are in
chainloader.c, freedos.c, and ntldr.c

Some descriptions of the semantics of these two fields:

https://www.win.tue.nl/~aeb/linux/fs/fat/fat-1.html

  The old 2-byte fields "total number of sectors" and "number of
  sectors per FAT" are now zero; this information is now found in
  the new 4-byte fields.

(Here given in the FAT32 EBPB section but the total sectors 16/32 bit
fields semantic is true of FAT12 and FAT16 too.)

https://wiki.osdev.org/FAT#BPB_.28BIOS_Parameter_Block.29

  19 | 2 | The total sectors in the logical volume. If this value is 0,
  it means there are more than 65535 sectors in the volume, and the actual
  count is stored in "Large Sectors (bytes 32-35).

  32 | 4 | Large amount of sector on media. This field is set if there
  are more than 65535 sectors in the volume.

(Doesn't specify what the "large" field is set to when unused, but as
mentioned mkfs.fat sets it to zero then.)

https://technet.microsoft.com/en-us/library/cc976796.aspx

  0x13 | WORD | 0x0000 |
  Small Sectors . The number of sectors on the volume represented in 16
  bits (< 65,536). For volumes larger than 65,536 sectors, this field
  has a value of zero and the Large Sectors field is used instead.

  0x20 | DWORD | 0x01F03E00 |
  Large Sectors . If the value of the Small Sectors field is zero, this
  field contains the total number of sectors in the FAT16 volume. If the
  value of the Small Sectors field is not zero, the value of this field
  is zero.

https://staff.washington.edu/dittrich/misc/fatgen103.pdf page 10

  BPB_TotSec16 | 19 | 2 |
  This field is the old 16-bit total count of sectors on the volume.
  This count includes the count of all sectors in all four regions of the
  volume. This field can be 0; if it is 0, then BPB_TotSec32 must be
  non-zero. For FAT32 volumes, this field must be 0. For FAT12 and
  FAT16 volumes, this field contains the sector count, and
  BPB_TotSec32 is 0 if the total sector count “fits” (is less than
  0x10000).

  BPB_TotSec32 | 32 | 4 |
  This field is the new 32-bit total count of sectors on the volume.
  This count includes the count of all sectors in all four regions of the
  volume. This field can be 0; if it is 0, then BPB_TotSec16 must be
  non-zero. For FAT32 volumes, this field must be non-zero. For
  FAT12/FAT16 volumes, this field contains the sector count if
  BPB_TotSec16 is 0 (count is greater than or equal to 0x10000).

(This specifies that an unused BPB_TotSec32 field is set to zero.)

By the way fix offsets in include/grub/fat.h.

Tested with lDebug booted in qemu via grub2's
FreeDOS direct loading support, refer to
https://bitbucket.org/ecm/ldosboot + https://bitbucket.org/ecm/ldebug

Signed-off-by: C. Masloch <pushbx@38.de>
Reviewed-by: Daniel Kiper <daniel.kiper@oracle.com>
2018-02-23 22:32:55 +01:00
Daniel Kiper 4e5414b2a1 i386/relocator: Align stack in grub_relocator64_efi relocator
Unified Extensible Firmware Interface Specification, Version 2.6,
section 2.3.4, x64 Platforms, boot services, says among others:
The stack must be 16-byte aligned. So, do it. Otherwise OS may
boot only by chance as it happens right now.

Signed-off-by: Daniel Kiper <daniel.kiper@oracle.com>
2017-02-02 22:24:47 +01:00
Daniel Kiper a620876e3b multiboot2: Add support for relocatable images
Currently multiboot2 protocol loads image exactly at address specified in
ELF or multiboot2 header. This solution works quite well on legacy BIOS
platforms. It is possible because memory regions are placed at predictable
addresses (though I was not able to find any spec which says that it is
strong requirement, so, it looks that it is just a goodwill of hardware
designers). However, EFI platforms are more volatile. Even if required
memory regions live at specific addresses then they are sometimes simply
not free (e.g. used by boot/runtime services on Dell PowerEdge R820 and
OVMF). This means that you are not able to just set up final image
destination on build time. You have to provide method to relocate image
contents to real load address which is usually different than load address
specified in ELF and multiboot2 headers.

This patch provides all needed machinery to do self relocation in image code.
First of all GRUB2 reads min_addr (min. load addr), max_addr (max. load addr),
align (required image alignment), preference (it says which memory regions are
preferred by image, e.g. none, low, high) from multiboot_header_tag_relocatable
header tag contained in binary (at this stage load addresses from multiboot2
and/or ELF headers are ignored). Later loader tries to fulfill request (not only
that one) and if it succeeds then it informs image about real load address via
multiboot_tag_load_base_addr tag. At this stage GRUB2 role is finished. Starting
from now executable must cope with relocations itself using whole static and
dynamic knowledge provided by boot loader.

This patch does not provide functionality which could do relocations using
ELF relocation data. However, I was asked by Konrad Rzeszutek Wilk and Vladimir
'phcoder' Serbinenko to investigate that thing. It looks that relevant machinery
could be added to existing code (including this patch) without huge effort.
Additionally, ELF relocation could live in parallel with self relocation provided
by this patch. However, during research I realized that first of all we should
establish the details how ELF relocatable image should look like and how it should
be build. At least to build proper test/example files.

So, this patch just provides support for self relocatable images. If ELF file
with relocs is loaded then GRUB2 complains loudly and ignores it. Support for
such files will be added later.

This patch was tested with Xen image which uses that functionality. However, this Xen
feature is still under development and new patchset will be released in about 2-3 weeks.

Signed-off-by: Daniel Kiper <daniel.kiper@oracle.com>
Reviewed-by: Vladimir Serbinenko <phcoder@gmail.com>
2016-10-27 15:55:16 +02:00
Daniel Kiper f2b6c20a25 multiboot2: Do not pass memory maps to image if EFI boot services are enabled
If image requested EFI boot services then skip multiboot2 memory maps.
Main reason for not providing maps is because they will likely be
invalid. We do a few allocations after filling them, e.g. for relocator
needs. Usually we do not care as we would have finished boot services.
If we keep boot services then it is easier/safer to not provide maps.
However, if image needs memory maps and they are not provided by bootloader
then it should get itself just before ExitBootServices() call.

Signed-off-by: Daniel Kiper <daniel.kiper@oracle.com>
Reviewed-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Reviewed-by: Vladimir Serbinenko <phcoder@gmail.com>
2016-10-27 15:55:00 +02:00
Daniel Kiper ba89c19f49 multiboot2: Add tags used to pass ImageHandle to loaded image
Add tags used to pass ImageHandle to loaded image if requested.
It is used by at least ExitBootServices() function.

Signed-off-by: Daniel Kiper <daniel.kiper@oracle.com>
Reviewed-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Reviewed-by: Vladimir Serbinenko <phcoder@gmail.com>
2016-10-27 15:54:46 +02:00
Daniel Kiper 9862b24121 i386/relocator: Add grub_relocator64_efi relocator
Add grub_relocator64_efi relocator. It will be used on EFI 64-bit platforms
when multiboot2 compatible image requests MULTIBOOT_TAG_TYPE_EFI_BS. Relocator
will set lower parts of %rax and %rbx accordingly to multiboot2 specification.
On the other hand processor mode, just before jumping into loaded image, will
be set accordingly to Unified Extensible Firmware Interface Specification,
Version 2.4 Errata B, section 2.3.4, x64 Platforms, boot services. This way
loaded image will be able to use EFI boot services without any issues.

Signed-off-by: Daniel Kiper <daniel.kiper@oracle.com>
Reviewed-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Reviewed-by: Vladimir Serbinenko <phcoder@gmail.com>
2016-10-27 15:53:43 +02:00
Daniel Kiper eba6db6323 relocator: Fix integer underflow. 2016-02-12 16:07:57 +01:00
Daniel Kiper 71783dc978 i386/relocator: Remove unused extern grub_relocator64_rip_addr
Signed-off-by: Daniel Kiper <daniel.kiper@oracle.com>
2015-05-07 18:00:47 +02:00
Daniel Kiper 8e5bc2f4d3 multiboot2: Fix information request tag size calculation
Signed-off-by: Daniel Kiper <daniel.kiper@oracle.com>
2015-02-14 19:26:04 +03:00