In order to be able to read from and write to model-specific registers,
two new modules are added. They are i386 specific, as the cpuid module.
rdmsr module registers the command rdmsr that allows reading from a MSR.
wrmsr module registers the command wrmsr that allows writing to a MSR.
wrmsr module is disabled if UEFI secure boot is enabled.
Please note that on SMP systems, interacting with a MSR that has a scope
per hardware thread, implies that the value only applies to the
particular cpu/core/thread that ran the command.
Also, if you specify a reserved or unimplemented MSR address, it will
cause a general protection exception (which is not currently being
handled) and the system will reboot.
Signed-off-by: Jesús Diéguez Fernández <jesusdf@gmail.com>
Reviewed-by: Daniel Kiper <daniel.kiper@oracle.com>
Describe the behaviour of GRUB when the TPM module is in use.
Signed-off-by: Matthew Garrett <mjg59@google.com>
Reviewed-by: Daniel Kiper <daniel.kiper@oracle.com>
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>
Update grub-mkconfig.in and 10_linux.in to support grub-probe's new
partuuid target. Update grub.texi documentation. The following table
shows how GRUB_DISABLE_LINUX_UUID, GRUB_DISABLE_LINUX_PARTUUID, and
initramfs detection interact:
Initramfs GRUB_DISABLE_LINUX_PARTUUID GRUB_DISABLE_LINUX_UUID Linux Root
detected Set Set ID Method
false false false part UUID
false false true part UUID
false true false dev name
false true true dev name
true false false fs UUID
true false true part UUID
true true false fs UUID
true true true dev name
Note: GRUB_DISABLE_LINUX_PARTUUID and GRUB_DISABLE_LINUX_UUID equate to
'false' when unset or set to any value other than 'true'.
GRUB_DISABLE_LINUX_PARTUUID defaults to 'true'.
Signed-off-by: Nicholas Vinson <nvinson234@gmail.com>
Reviewed-by: Daniel Kiper <daniel.kiper@oracle.com>
"F2FS (Flash-Friendly File System) is flash-friendly file system which was merged
into Linux kernel v3.8 in 2013.
The motive for F2FS was to build a file system that from the start, takes into
account the characteristics of NAND flash memory-based storage devices (such as
solid-state disks, eMMC, and SD cards).
F2FS was designed on a basis of a log-structured file system approach, which
remedies some known issues of the older log structured file systems, such as
the snowball effect of wandering trees and high cleaning overhead. In addition,
since a NAND-based storage device shows different characteristics according to
its internal geometry or flash memory management scheme (such as the Flash
Translation Layer or FTL), it supports various parameters not only for
configuring on-disk layout, but also for selecting allocation and cleaning
algorithm.", quote by https://en.wikipedia.org/wiki/F2FS.
The source codes for F2FS are available from:
http://git.kernel.org/cgit/linux/kernel/git/jaegeuk/f2fs.githttp://git.kernel.org/cgit/linux/kernel/git/jaegeuk/f2fs-tools.git
This patch has been integrated in OpenMandriva Lx 3.
https://www.openmandriva.org/
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
Signed-off-by: Pete Batard <pete@akeo.ie>
Signed-off-by: Daniel Kiper <daniel.kiper@oracle.com>
Reviewed-by: Daniel Kiper <daniel.kiper@oracle.com>
Add support for multiple, shared, early initrd images. These early
images will be loaded in the order declared, and all will be loaded
before the initrd image.
While many classes of data can be provided by early images, the
immediate use case would be for distributions to provide CPU
microcode to mitigate the Meltdown and Spectre vulnerabilities.
There are two environment variables provided for declaring the early
images.
* GRUB_EARLY_INITRD_LINUX_STOCK is for the distribution declare
images that are provided by the distribution or installed packages.
If undeclared, this will default to a set of common microcode image
names.
* GRUB_EARLY_INITRD_LINUX_CUSTOM is for user created images. User
images will be loaded after the stock images.
These separate configurations allow the distribution and user to
declare different image sets without clobbering each other.
This also makes a minor update to ensure that UUID partition labels
stay disabled when no initrd image is found, even if early images are
present.
This is a continuation of a previous patch published by Christian
Hesse in 2016:
http://lists.gnu.org/archive/html/grub-devel/2016-02/msg00025.html
Down stream Gentoo bug:
https://bugs.gentoo.org/645088
Signed-off-by: Robin H. Johnson <robbat2@gentoo.org>
Signed-off-by: Matthew S. Turnbull <sparky@bluefang-logic.com>
Reviewed-by: Daniel Kiper <daniel.kiper@oracle.com>
delete: xen_linux, xen_initrd, xen_xsm
add: xen_module
This update bases on
commit 0edd750e50
Author: Vladimir Serbinenko <phcoder@gmail.com>
Date: Fri Jan 22 10:18:47 2016 +0100
xen_boot: Remove obsolete module type distinctions.
Also bases on the module loading mechanism of Xen code:
488c2a8 docs/arm64: clarify the documention for loading XSM support
67831c4 docs/arm64: update the documentation for loading XSM support
ca32012 xen/arm64: check XSM Magic from the second unknown module.
Signed-off-by: Fu Wei <fu.wei@linaro.org>
Reviewed-by: Julien Grall <julien.grall@arm.com>
Reviewed-by: Daniel Kiper <daniel.kiper@oracle.com>
The current documentation for the special environment variable
"default" is confusing and unclear. This patch attempts to clean it
up.
In particular, the current documentation refers to the "number or
title", but then in the example it gives, the menu entries and
submenus all have numbers *in* their title; furthermore, there is no
example given about how to choose the number, or any indication about
whether counting is zero-indexed or 1-indexed.
Having a cleaner example and presenting all variants (numeric, title,
and id) should make it clearer to the user.
Signed-off-by: Daniel Kahn Gillmor <dkg@fifthhorseman.net>
Network boot autoconfiguration sets default server to next server IP
(siaddr) from BOOTP/DHCP reply, but manual configuration using net_bootp
exports only server name. Unfortunately semantic of server name is not
clearly defined. BOOTP RFC 951 defines it only for client request, and
DHCP RFC 1541 only mentions it, without any implied usage. It looks like
this field is mostly empty in server replies.
Export next server IP as net_<interface>_next_server variable. This allows
grub configuration script to set $root/$prefix based on information obtained
by net_bootp.
Reported and tested by: Nikunj A Dadhania <nikunj@linux.vnet.ibm.com>
Cc: nikunj@linux.vnet.ibm.com
v2: change variable name to net_<interface>_next_server as discussed on the list
superusers controls both CLI and editing. Also explicitly mention that
empty superusers disables them.
"Access to menuentry" is a bit vague - change to "execute menuentry"
to make it obvious, what access is granted.
From RFC1542:
The 'giaddr' field is rather poorly named. It exists to facilitate
the transfer of BOOTREQUEST messages from a client, through BOOTP
relay agents, to servers on different networks than the client.
Similarly, it facilitates the delivery of BOOTREPLY messages from the
servers, through BOOTP relay agents, back to the client. In no case
does it represent a general IP router to be used by the client. A
BOOTP client MUST set the 'giaddr' field to zero (0.0.0.0) in all
BOOTREQUEST messages it generates.
A BOOTP client MUST NOT interpret the 'giaddr' field of a BOOTREPLY
message to be the IP address of an IP router. A BOOTP client SHOULD
completely ignore the contents of the 'giaddr' field in BOOTREPLY
messages.
Leave code ifdef'd out for the time being in case we see regression.
Suggested by: Rink Springer <rink@rink.nu>
Closes: 43396
Add a new timeout_style environment variable and a corresponding
GRUB_TIMEOUT_STYLE configuration key for grub-mkconfig. This
controls hidden-timeout handling more simply than the previous
arrangements, and pressing any hotkeys associated with menu entries
during the hidden timeout will now boot the corresponding menu entry
immediately.
GRUB_HIDDEN_TIMEOUT=<non-empty> + GRUB_TIMEOUT=<non-zero> now
generates a warning, and if it shows the menu it will do so as if
the second timeout were not present. Other combinations are
translated into reasonable equivalents.
Remove reference to grub-default from description of saved default entry.
Also mention that GRUB_DEFAULT=saved depends on availability of environment
block.
[v0] Accepted with modifications by phcoder@
[v1] Introduce subsections within Security
[v1] Correct errors regarding public key files not being automatically signature-checked in trust and verify_detached
[v1] Replace check_signatures=enforce with check_signatures set to enforce
[v1] Move detailed discussion of using signatures out of check_signatures environment variable description
[v1] Use long form for option flags to security-relevant commands
[v2] Explain the key fingerprint format for distrust and list_trusted.
[v2] Eliminates references to grub-mkimage and UEFI Secure Boot.
[v3] Updates in response to addition of --skip-sig to trust and verify_detached
[ ] Restore @xref for cross-references at the start of sentences
