proxmox-mirrors/grub2
1
0
Fork 0
mirror of https://git.proxmox.com/git/grub2 synced 2025-07-26 08:24:16 +00:00
Code Issues Actions Packages Projects Releases Wiki Activity

templates: Disable the os-prober by default

Browse Source 
The os-prober is enabled by default what may lead to potentially
dangerous use cases and borderline opening attack vectors. This
patch disables the os-prober, adds warning messages and updates
GRUB_DISABLE_OS_PROBER configuration option documentation. This
way we make it clear that the os-prober usage is not recommended.

Simplistic nature of this change allows downstream vendors, who
really want os-prober to be enabled out of the box in their
relevant products, easily revert to it's old behavior.

Reported-by: NyankoSec (<nyanko@10x.moe>, https://twitter.com/NyankoSec),
             working with SSD Secure Disclosure
Signed-off-by: Alex Burmashev <alexander.burmashev@oracle.com>
Reviewed-by: Daniel Kiper <daniel.kiper@oracle.com>
This commit is contained in:
Alex Burmashev 2021-02-16 11:12:12 +01:00 committed by Daniel Kiper
parent 42facd5772
commit e346414725
2 changed files with 14 additions and 9 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

18
docs/grub.texi
View File

@ -1519,10 +1519,13 @@ boot sequence. If you have problems, set this option to @samp{text} and
GRUB will tell Linux to boot in normal text mode. GRUB will tell Linux to boot in normal text mode.
@item GRUB_DISABLE_OS_PROBER @item GRUB_DISABLE_OS_PROBER
Normally, @command{grub-mkconfig} will try to use the external The @command{grub-mkconfig} has a feature to use the external
@command{os-prober} program, if installed, to discover other operating @command{os-prober} program to discover other operating systems installed on
systems installed on the same system and generate appropriate menu entries the same machine and generate appropriate menu entries for them. It is disabled
for them. Set this option to @samp{true} to disable this. by default since automatic and silent execution of @command{os-prober}, and
creating boot entries based on that data, is a potential attack vector. Set
this option to @samp{false} to enable this feature in the
@command{grub-mkconfig} command.
@item GRUB_OS_PROBER_SKIP_LIST @item GRUB_OS_PROBER_SKIP_LIST
List of space-separated FS UUIDs of filesystems to be ignored from os-prober List of space-separated FS UUIDs of filesystems to be ignored from os-prober
@ -1850,10 +1853,9 @@ than zero; otherwise 0.
@section Multi-boot manual config @section Multi-boot manual config
Currently autogenerating config files for multi-boot environments depends on Currently autogenerating config files for multi-boot environments depends on
os-prober and has several shortcomings. While fixing it is scheduled for the os-prober and has several shortcomings. Due to that it is disabled by default.
next release, meanwhile you can make use of the power of GRUB syntax and do it It is advised to use the power of GRUB syntax and do it yourself. A possible
yourself. A possible configuration is detailed here, feel free to adjust to your configuration is detailed here, feel free to adjust to your needs.
needs.
First create a separate GRUB partition, big enough to hold GRUB. Some of the First create a separate GRUB partition, big enough to hold GRUB. Some of the
following entries show how to load OS installer images from this same partition, following entries show how to load OS installer images from this same partition,

5
util/grub.d/30_os-prober.in
View File

@ -26,7 +26,8 @@ export TEXTDOMAINDIR="@localedir@"
. "$pkgdatadir/grub-mkconfig_lib" . "$pkgdatadir/grub-mkconfig_lib"
if [ "x${GRUB_DISABLE_OS_PROBER}" = "xtrue" ]; then if [ "x${GRUB_DISABLE_OS_PROBER}" = "xfalse" ]; then
gettext_printf "os-prober will not be executed to detect other bootable partitions.\nSystems on them will not be added to the GRUB boot configuration.\nCheck GRUB_DISABLE_OS_PROBER documentation entry.\n"
exit 0 exit 0
fi fi
@ -39,6 +40,8 @@ OSPROBED="`os-prober | tr ' ' '^' | paste -s -d ' '`"
if [ -z "${OSPROBED}" ] ; then if [ -z "${OSPROBED}" ] ; then
# empty os-prober output, nothing doing # empty os-prober output, nothing doing
exit 0 exit 0
else
grub_warn "$(gettext_printf "os-prober was executed to detect other bootable partitions.\nIt's output will be used to detect bootable binaries on them and create new boot entries.")"
fi fi
osx_entry() { osx_entry() {