It was possible to overflow the value of mod->ref_count, a signed
integer, by repeatedly invoking insmod on an already loaded module.
This led to a use-after-free. As once ref_count was overflowed it became
possible to unload the module while there was still references to it.
This resolves the issue by using grub_add() to check if the ref_count
will overflow and then stops further increments. Further changes were
also made to grub_dl_unref() to check for the underflow condition and
the reference count was changed to an unsigned 64-bit integer.
Reported-by: B Horn <b@horn.uk>
Signed-off-by: B Horn <b@horn.uk>
Reviewed-by: Daniel Kiper <daniel.kiper@oracle.com>
To utilize the key protectors framework, there must be a way to protect
full-disk encryption keys in the first place. The grub-protect tool
includes support for the TPM2 key protector but other protectors that
require setup ahead of time can be supported in the future.
For the TPM2 key protector, the intended flow is for a user to have
a LUKS 1 or LUKS 2-protected fully-encrypted disk. The user then creates
a new LUKS key file, say by reading /dev/urandom into a file, and creates
a new LUKS key slot for this key. Then, the user invokes the grub-protect
tool to seal this key file to a set of PCRs using the system's TPM 2.0.
The resulting sealed key file is stored in an unencrypted partition such
as the EFI System Partition (ESP) so that GRUB may read it. The user also
has to ensure the cryptomount command is included in GRUB's boot script
and that it carries the requisite key protector (-P) parameter.
Sample usage:
$ dd if=/dev/urandom of=luks-key bs=1 count=32
$ sudo cryptsetup luksAddKey /dev/sdb1 luks-key --pbkdf=pbkdf2 --hash=sha512
To seal the key with TPM 2.0 Key File (recommended):
$ sudo grub-protect --action=add \
--protector=tpm2 \
--tpm2-pcrs=0,2,4,7,9 \
--tpm2key \
--tpm2-keyfile=luks-key \
--tpm2-outfile=/boot/efi/efi/grub/sealed.tpm
Or, to seal the key with the raw sealed key:
$ sudo grub-protect --action=add \
--protector=tpm2 \
--tpm2-pcrs=0,2,4,7,9 \
--tpm2-keyfile=luks-key \
--tpm2-outfile=/boot/efi/efi/grub/sealed.key
Then, in the boot script, for TPM 2.0 Key File:
tpm2_key_protector_init --tpm2key=(hd0,gpt1)/efi/grub/sealed.tpm
cryptomount -u <SDB1_UUID> -P tpm2
Or, for the raw sealed key:
tpm2_key_protector_init --keyfile=(hd0,gpt1)/efi/grub/sealed.key --pcrs=0,2,4,7,9
cryptomount -u <SDB1_UUID> -P tpm2
The benefit of using TPM 2.0 Key File is that the PCR set is already
written in the key file, so there is no need to specify PCRs when
invoking tpm2_key_protector_init.
Signed-off-by: Hernan Gatta <hegatta@linux.microsoft.com>
Signed-off-by: Gary Lin <glin@suse.com>
Reviewed-by: Stefan Berger <stefanb@linux.ibm.com>
Reviewed-by: Daniel Kiper <daniel.kiper@oracle.com>
Tested-by: Stefan Berger <stefanb@linux.ibm.com>
The SBAT metadata is read from CSV file and transformed into an ELF note
with the -s option.
Signed-off-by: Daniel Axtens <dja@axtens.net>
Signed-off-by: Sudhakar Kuppusamy <sudhakar@linux.ibm.com>
Reviewed-by: Daniel Kiper <daniel.kiper@oracle.com>
In order to store the SBAT data we create a new ELF note. The string
".sbat", zero-padded to 4 byte alignment, shall be entered in the name
field. The string "SBAT"'s ASCII values, 0x53424154, should be entered
in the type field.
Signed-off-by: Daniel Axtens <dja@axtens.net>
Signed-off-by: Sudhakar Kuppusamy <sudhakar@linux.ibm.com>
Reviewed-by: Daniel Kiper <daniel.kiper@oracle.com>
For NX the GRUB binary has to announce that it is compatible with the
NX feature. This implies that when loading the executable GRUB image
several attributes are true:
- the binary doesn't need an executable stack,
- the binary doesn't need sections to be both executable and writable,
- the binary knows how to use the EFI Memory Attributes Protocol on code
it is loading.
This patch:
- adds a definition for the PE DLL Characteristics flag GRUB_PE32_NX_COMPAT,
- changes grub-mkimage to set that flag.
Signed-off-by: Peter Jones <pjones@redhat.com>
Signed-off-by: Jan Setje-Eilers <jan.setjeeilers@oracle.com>
Signed-off-by: Mate Kukri <mate.kukri@canonical.com>
Reviewed-by: Daniel Kiper <daniel.kiper@oracle.com>
Assembly code looks for modules at __bss_start. Make this position explicit
rather than matching BSS alignment and module alignment.
Signed-off-by: Vladimir Serbinenko <phcoder@gmail.com>
Reviewed-by: Daniel Kiper <daniel.kiper@oracle.com>
As reported by Victoriia Egorova in bug 65880, grub-mkrescue does not
verify that the expected argument of an option like -d or -k does really
exist in argv. So, check the loop counter before incrementing it inside
the loop which copies argv to argp_argv. Issue an error message similar
to what older versions of grub-mkrescue did with a missing argument,
e.g. 2.02.
Fixes: https://savannah.gnu.org/bugs/index.php?65880
Signed-off-by: Thomas Schmitt <scdbackup@gmx.net>
Reviewed-by: Daniel Kiper <daniel.kiper@oracle.com>
Allocate memory if needed, while saving the corresponding release
operation, reducing the amount of code and code complexity.
Signed-off-by: Tianjia Zhang <tianjia.zhang@linux.alibaba.com>
Reviewed-by: Daniel Kiper <daniel.kiper@oracle.com>
Add functionality to disable command line interface access and editing of GRUB
menu entries if GRUB image is built with --disable-cli.
Signed-off-by: Alec Brown <alec.r.brown@oracle.com>
Reviewed-by: Vladimir Serbinenko <phcoder@gmail.com>
Reviewed-by: Daniel Kiper <daniel.kiper@oracle.com>
This is required if the pathname contains spaces or GRUB shell
metacharacters else the generated config file check will fail.
Signed-off-by: Pascal Hambourg <pascal@plouf.fr.eu.org>
Reviewed-by: Daniel Kiper <daniel.kiper@oracle.com>
_split_longopt() was the bash-completion private API and removed since
bash-completion 2.12. This commit initializes the bash-completion
general variables with _init_completion() to avoid the potential
"command not found" error.
Although bash-completion 2.12 introduces _comp_initialize() to deprecate
_init_completion(), _init_completion() is still chosen for the better
backward compatibility.
Signed-off-by: Gary Lin <glin@suse.com>
Reviewed-by: Daniel Kiper <daniel.kiper@oracle.com>
We reinstated these functions before the 2.12 release with a warning
such that users upgrading to 2.12 who had custom scripts using them
would not get broken in the upgrade and agreed to remove them after
the 2.12 release. This removes them accordingly.
This reverts commit e7a831963 (templates: Reinstate unused version
comparison functions with warning).
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Cc: Daniel Kiper <daniel.kiper@oracle.com>
Signed-off-by: Julian Andres Klode <julian.klode@canonical.com>
Reviewed-by: Daniel Kiper <daniel.kiper@oracle.com>
There are two system directories for bash-completion scripts. One is
/usr/share/bash-completion/completions/ and the other is
/etc/bash_completion.d/. The "etc" scripts are loaded in advance and
for backward compatibility while the "usr" scripts are loaded on demand.
To load scripts on demand it requires a corresponding script for every
command. So, the main bash-completion script is split into several
subscripts for different "grub-*" commands. To share the code the real
completion functions are still implemented in "grub" and each
subscript sources "grub" and invokes the corresponding function.
Signed-off-by: Gary Lin <glin@suse.com>
Reviewed-by: Daniel Kiper <daniel.kiper@oracle.com>
The 64-bit ABI defines ld.so to be /lib/ld-x86-64.so.1.
Signed-off-by: Samuel Thibault <samuel.thibault@ens-lyon.org>
Reviewed-by: Daniel Kiper <daniel.kiper@oracle.com>
The HAVE_LIBZFS is defined by libzfs test and hence conflicts with
manual definition. On NetBSD it ends up detecting zfs but not detecting
nvpair and creates confusion. Split them.
Signed-off-by: Vladimir Serbinenko <phcoder@gmail.com>
Reviewed-by: Daniel Kiper <daniel.kiper@oracle.com>
It's not available on NetBSD outside of syslog. Using strerror() is more
reliable as we retrieve errno immediately rather than down the stack.
Signed-off-by: Vladimir Serbinenko <phcoder@gmail.com>
Reviewed-by: Daniel Kiper <daniel.kiper@oracle.com>
The commit 3f9eace2d (util/grub-install: Delay copying files to
{grubdir,platdir} after install_device was validated) delaying
copying of files caused a regression when installing without an
existing directory structure.
This patch ensures that the platform directory actually exists by the
time the code tries to canonicalize its filename.
Fixes: 3f9eace2d (util/grub-install: Delay copying files to {grubdir,platdir} after install_device was validated)
Signed-off-by: Mate Kukri <mate.kukri@canonical.com>
Reviewed-by: Daniel Kiper <daniel.kiper@oracle.com>
The add_tar_files() function currently iterates through a directory's
content using readdir(), which doesn't guarantee a specific order. This
lack of deterministic behavior impacts reproducibility in the build process.
This commit resolves the issue by introducing sorting functionality.
The list retrieved by readdir() is now sorted alphabetically before
incorporation into the tar archive, ensuring consistent and predictable
file ordering within the archive.
On the occasion fix tfp memory leak.
Signed-off-by: Michael Chang <mchang@suse.com>
Signed-off-by: Bernhard Wiedemann <bwiedemann@suse.com>
Reviewed-by: Daniel Kiper <daniel.kiper@oracle.com>
This change mirrors a previous fix [1] but is specific to images
generated by grub-mkstandalone.
The former fix, commit 85a7be241 (util/mkimage: Use stable timestamp
when generating binaries.), focused on utilizing a stable timestamp
during binary generation in the util/mkimage context. This commit
extends that approach to the images produced by grub-mkstandalone,
ensuring consistency and stability in timestamps across all generated
binaries.
[1] 85a7be241 util/mkimage: Use stable timestamp when generating binaries.
Signed-off-by: Michael Chang <mchang@suse.com>
Signed-off-by: Bernhard Wiedemann <bwiedemann@suse.com>
Reviewed-by: Daniel Kiper <daniel.kiper@oracle.com>
Revert the commit a79c567f6 (templates: Remove unused version comparison
functions) and add a warning to the functions that they are deprecated.
Removing the functions directly caused a lot of upgrade issues
with custom user scripts that called the functions. In Debian and
Ubuntu, grub-mkconfig is invoked as a post-installation script
and would fail, causing upgrades to fail halfway through and
putting the package manager into an inconsistent state.
FWIW, we get one bug per 2 weeks basically, for an interim Ubuntu
release which generally does not receive much usage, that is a high
number.
The proposal is to pick this for 2.12 and directly after the release
remove it again. Then users will have time to fix their scripts without
systems breaking immediately.
This reverts commit a79c567f6 (templates: Remove unused version
comparison functions).
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Cc: Daniel Kiper <daniel.kiper@oracle.com>
Signed-off-by: Julian Andres Klode <julian.klode@canonical.com>
Reviewed-by: Daniel Kiper <daniel.kiper@oracle.com>
Previously grub-install copied modules to grubdir before doing any
validation on the install_device.
When grub-install was called with an invalid install_device, modules
were already copied to /boot before it found out and was forced to rely
on atexit() rollback.
This patch delays copying the modules after at least some install_device
validation was done, and thus reduces reliance on successful rollback.
Signed-off-by: Mate Kukri <mate.kukri@canonical.com>
Reviewed-by: Daniel Kiper <daniel.kiper@oracle.com>
The function argp_parser() in util/grub-mount.c lacks a check on the
sanity of the file path when parsing parameters. This results in
a segmentation fault if a partition is mounted to a non-existent path.
Signed-off-by: Qiumiao Zhang <zhangqiumiao1@huawei.com>
Reviewed-by: Daniel Kiper <daniel.kiper@oracle.com>
When grub-install is run with the verbose option, it will print a log
message indicating the grub-mkimage command and arguments used.
GRUB no longer calls the grub-mkimage binary internally, however the
command logged is a command that if run should effectively be what
grub-install used. However, as this has changed some of the newer
options have been incorrectly added so that the printed command fails
when run separately. This change makes the displayed command run as
intended.
Signed-off-by: Glenn Washburn <development@efficientek.com>
Reviewed-by: Daniel Kiper <daniel.kiper@oracle.com>
This is a preparatory patch to make the following patch less cluttered. The
only visible change made here is to not print extra spaces when either or
both --note or --disable-shim-lock are not given and to not print an extra
space at the end of the command. The latter is done by constructing the
trailing argument string with spaces in front of each argument rather than
trailing. The allocation of the argument string is made precise, which has
the benefit of saving a few bytes, but more importantly self-documenting
what the needed allocated bytes are. Also, unneeded braces are removed from
an if block.
Signed-off-by: Glenn Washburn <development@efficientek.com>
Reviewed-by: Daniel Kiper <daniel.kiper@oracle.com>
It turns out that setting $xen_version in linux_entry_xsm() override
$xen_version in the loop over $reverse_sorted_xen_list. This means
that only one entry per Xen version is going to enable XSM, but all
further entries are going to have "(XSM enabled)" in their titles
without enabling XSM.
When a "xenpolicy-$xen_version" file was found for the current
$xen_version, it would overwrite $xen_version to add "(XSM enabled)" to
the menu entry title. Once updated, the next call to linux_entry_xsm()
would also have this modified $xen_version and would look for the file
"xenpolicy-*(XSM enabled)" and fail.
Signed-off-by: Anthony PERARD <anthony.perard@citrix.com>
Reviewed-by: Daniel Kiper <daniel.kiper@oracle.com>
On an unmerged-usr system, grub-mkconfig errors out with the following
error due to /usr/bin/sh not existing:
/usr/sbin/grub-mkconfig: /etc/grub.d/25_bli: /usr/bin/sh: bad interpreter: No such file or directory
Use a /bin/sh shebang to fix the error as well as match the other
existing files.
Fixes: 158a6583e (util/grub.d/25_bli.in: Activate bli module on EFI)
Signed-off-by: Oskari Pirhonen <xxc3ncoredxx@gmail.com>
Reviewed-by: Glenn Washburn <development@efficientek.com>
Reviewed-by: Daniel Kiper <daniel.kiper@oracle.com>
Reviewed-by: Oliver Steffen <osteffen@redhat.com>
acpi actually needs to access PCI, while pci-arbiter will not be making
use of ACPI, so we need to start acpi first.
Signed-off-by: Samuel Thibault <samuel.thibault@ens-lyon.org>
Reviewed-by: Daniel Kiper <daniel.kiper@oracle.com>
According to the relocation documentation, the following function names are
renamed to show their exact meaning:
- from grub_loongarch64_xxx64_hi12() to grub_loongarch64_abs64_hi12(),
- from grub_loongarch64_xxx64_hi12() to grub_loongarch64_abs64_lo20().
Signed-off-by: Xiaotian Wu <wuxiaotian@loongson.cn>
Reviewed-by: Daniel Kiper <daniel.kiper@oracle.com>
We already have the pc variable, no need to calculate it again.
Signed-off-by: Xiaotian Wu <wuxiaotian@loongson.cn>
Reviewed-by: Daniel Kiper <daniel.kiper@oracle.com>
Ensure the generated unidata.c file is deterministic by sorting the
keys of the dict.
Signed-off-by: Alexander Kanavin <alex@linutronix.de>
Reviewed-by: Daniel Kiper <daniel.kiper@oracle.com>
Add a new configuration drop-in file that loads the bli module and runs
the command if booting on the EFI platform.
Signed-off-by: Oliver Steffen <osteffen@redhat.com>
Reviewed-by: Daniel Kiper <daniel.kiper@oracle.com>
There are 3 implementations of a GUID in GRUB. Replace them with
a common one, placed in types.h.
It uses the "packed" flavor of the GUID structs, the alignment attribute
is dropped, since it is not required.
Signed-off-by: Oliver Steffen <osteffen@redhat.com>
Reviewed-by: Daniel Kiper <daniel.kiper@oracle.com>
Commit f23bc6510 (Transform -C option to grub-mkstandalone to
--core-compress available in all grub-install flavours.) declared
a new long option for specifying the compression method to use for
the core image.
However, the option key has not been replaced in the parser function,
it still expects the old one formerly used by grub-mkstandalone.
Because of this the option is not recognized by any of the utils for
which it is listed as supported.
Signed-off-by: Ákos Nagy <nagyakos@outlook.com>
Reviewed-by: Daniel Kiper <daniel.kiper@oracle.com>
This patch adds LoongArch to the GRUB build system and various tools,
so GRUB can be built on LoongArch as a UEFI application.
Signed-off-by: Zhou Yang <zhouyang@loongson.cn>
Signed-off-by: Xiaotian Wu <wuxiaotian@loongson.cn>
Reviewed-by: Daniel Kiper <daniel.kiper@oracle.com>
A new set of relocation types was added in the LoongArch ELF psABI v2.00
spec [1], [2] to replace the stack-based scheme in v1.00. Toolchain
support is available from binutils 2.40 and gcc 13 onwards.
This patch adds support for the new relocation types, that are simpler
to handle (in particular, stack operations are gone). Support for the
v1.00 relocs are kept for now, for compatibility with older toolchains.
[1] https://github.com/loongson/LoongArch-Documentation/pull/57
[2] https://loongson.github.io/LoongArch-Documentation/LoongArch-ELF-ABI-EN.html#_appendix_revision_history
Signed-off-by: Xiaotian Wu <wuxiaotian@loongson.cn>
Reviewed-by: Daniel Kiper <daniel.kiper@oracle.com>
This patch adds support of the stack-based LoongArch relocations
throughout GRUB, including tools, dynamic linkage, and support for
conversion of ELF relocations into PE ones. A stack machine is required
to handle these per the spec [1] (see the R_LARCH_SOP types), of which
a simple implementation is included.
These relocations are produced by binutils 2.38 and 2.39, while the newer
v2.00 relocs require more recent toolchain (binutils 2.40+ & gcc 13+, or
LLVM 16+). GCC 13 has not been officially released as of early 2023, so
support for v1.00 relocs are expected to stay relevant for a while.
[1] https://loongson.github.io/LoongArch-Documentation/LoongArch-ELF-ABI-EN.html#_relocations
Signed-off-by: Zhou Yang <zhouyang@loongson.cn>
Signed-off-by: Xiaotian Wu <wuxiaotian@loongson.cn>
Reviewed-by: Daniel Kiper <daniel.kiper@oracle.com>
In grub-module-verifierXX.c, the function grub_module_verifyXX() performs an
initial check that the ELF section headers are within the module's size, but
doesn't check if the sections being accessed have contents that are within the
module's size. In particular, we need to check that sh_offset and sh_size are
less than the module's size. However, for some section header types we don't
need to make these checks. For the type SHT_NULL, the section header is marked
as inactive and the rest of the members within the section header have undefined
values, so we don't need to check for sh_offset or sh_size. In the case of the
type SHT_NOBITS, sh_offset has a conceptual offset which may be beyond the
module size. Also, this type's sh_size may have a non-zero size, but a section
of this type will take up no space in the module. This can all be checked in the
function get_shdr(), but in order to do so, the parameter module_size must be
added to functions so that the value of the module size can be used in
get_shdr() from grub_module_verifyXX().
Also, had to rework some for loops to ensure the index passed to get_shdr() is
within bounds.
Signed-off-by: Alec Brown <alec.r.brown@oracle.com>
Reviewed-by: Daniel Kiper <daniel.kiper@oracle.com>
The xenpolicy variable was left set from previous function call. This
resulted in all-but-first menu entries including XSM policy, even if it
did not exist.
Fix this by initializing the xenpolicy variable.
Signed-off-by: Marek Marczykowski-Górecki <marmarek@invisiblethingslab.com>
Reviewed-by: Daniel Kiper <daniel.kiper@oracle.com>
The final piece needed to add UEFI file system transposition support is to
ensure the boot media can be located regardless of how the boot partition
was instantiated. Especially, we do not want to be reliant on brittle
partition UUIDs, as these only work if a boot media is duplicated at the
block level and not at the file system level.
To accomplish this for EFI boot, we now create a UUID file in a .disk/
directory, that can then be searched for.
Note: The switch from make_image_fwdisk_abs() to make_image_abs() is
needed in order to use the search functionality.
Signed-off-by: Pete Batard <pete@akeo.ie>
Reviewed-by: Daniel Kiper <daniel.kiper@oracle.com>
To enable file system transposition support for UEFI, we also must ensure that
there exists a copy of the EFI bootloaders, that are currently embedded in the
efi.img for xorriso, at their expected UEFI location on the ISO 9660 file system.
This is accomplished by removing the use of a temporary directory to create the
efi/ content, to instead place it at the root of the ISO 9660 content.
Signed-off-by: Pete Batard <pete@akeo.ie>
Reviewed-by: Daniel Kiper <daniel.kiper@oracle.com>
In order to add file system transposition support for UEFI, i.e. the ability
to copy the content of an grub-mkrescue ISO 9660 image onto user-formatted
media, and have that boot on UEFI systems, the first thing we need to do is
add support for the file systems that are natively handled by UEFI. This
mandatorily includes FAT, but we also include NTFS as the latter is also
commonly supported on modern x64 platforms.
Signed-off-by: Pete Batard <pete@akeo.ie>
Reviewed-by: Daniel Kiper <daniel.kiper@oracle.com>
SC2120 (warning): function references arguments, but none are ever passed.
In grub-completion.bash.in line 63:
__grub_get_options_from_help () {
^-- SC2120 (warning)
local prog
if [ $# -ge 1 ]; then
prog="$1"
The arg of __grub_get_options_from_help() is optional. So, the current
code meets the exception and does not need to be modified. Ignoring the
warning then.
More: https://github.com/koalaman/shellcheck/wiki/SC2120
Signed-off-by: t.feng <fengtao40@huawei.com>
Reviewed-by: Daniel Kiper <daniel.kiper@oracle.com>
SC2155 (warning): Declare and assign separately to avoid masking return values.
The exit status of the command is overridden by the exit status of the
creation of the local variable.
In grub-completion.bash.in line 115:
local config_file=$(__grub_dir)/grub.cfg
^---------^ SC2155 (warning)
In grub-completion.bash.in line 126:
local grub_dir=$(__grub_dir)
^------^ SC2155 (warning)
More: https://github.com/koalaman/shellcheck/wiki/SC2155
Signed-off-by: t.feng <fengtao40@huawei.com>
Reviewed-by: Daniel Kiper <daniel.kiper@oracle.com>
SC2207 (warning): Prefer mapfile or read -a to split
command output (or quote to avoid splitting).
In grub-completion.bash.in line 56:
COMPREPLY=($(compgen -P "${2-}" -W "${1-}" -S "${4-}" -- "$cur"))
^-- SC2207 (warning)
In grub-completion.bash.in line 119:
COMPREPLY=( $(compgen \
^-- SC2207 (warning)
In grub-completion.bash.in line 128:
COMPREPLY=( $( compgen -f -X '!*/*.mod' -- "${grub_dir}/$cur" | {
^-- SC2207 (warning)
COMPREPLY=($(command)) are doing unquoted command expansion in an array.
This will invoke the shell's sloppy word splitting and glob expansion.
If we want to split the output into lines or words, use read -r and
loops will be better. This prevents the shell from doing unwanted
splitting and glob expansion, and therefore avoiding problems with
output containing spaces or special characters.
More: https://github.com/koalaman/shellcheck/wiki/SC2207
Signed-off-by: t.feng <fengtao40@huawei.com>
Reviewed-by: Daniel Kiper <daniel.kiper@oracle.com>
SC2070 (error): -n doesn't work with unquoted arguments.
Quote or use [[ ]].
In grub-completion.bash.in line 130:
[ -n $tmp ] && {
^--^ SC2070 (error)
More: https://github.com/koalaman/shellcheck/wiki/SC2070
Signed-off-by: t.feng <fengtao40@huawei.com>
Reviewed-by: Daniel Kiper <daniel.kiper@oracle.com>
Only perform call to fwsetup if one is on EFI platform. On all other
platforms fwsetup command does not exists, and thus returns 0 and
a useless uefi-firmware menu entry gets generated.
Signed-off-by: Dimitri John Ledkov <dimitri.ledkov@canonical.com>
Reviewed-by: Daniel Kiper <daniel.kiper@oracle.com>
This enables an early failure; for i386-ieee1275 and powerpc-ieee1275 on
Linux, without /dev/nvram the system may be left in an unbootable state.
Signed-off-by: Ismael Luceno <iluceno@suse.de>
Reviewed-by: Daniel Kiper <daniel.kiper@oracle.com>
