Bug 1819184 - rescue kernel name should use hashed machine-id
Summary: rescue kernel name should use hashed machine-id
Keywords:
Status: CLOSED EOL
Alias: None
Product: Fedora
Classification: Fedora
Component: dracut
Version: 32
Hardware: Unspecified
OS: Unspecified
unspecified
unspecified
Target Milestone: ---
Assignee: dracut-maint-list
QA Contact: Fedora Extras Quality Assurance
URL:
Whiteboard:
Depends On:
Blocks:
TreeView+ depends on / blocked
 
Reported: 2020-03-31 12:18 UTC by Steve
Modified: 2022-12-31 02:58 UTC (History)
4 users (show)

Fixed In Version:
Doc Type: If docs needed, set a value
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Clone Of:
Environment:
Last Closed: 2021-05-25 15:51:36 UTC
Type: Bug
Embargoed:


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Description Steve 2020-03-31 12:18:19 UTC
Description of problem:

The rescue kernel name contains the machine-id, which is considered confidential.

According to the the "machine-id" man page:

'[The machine ID] should be considered "confidential", and must not be exposed in untrusted environments, in particular on the network.'

Such exposure can occur when people post the contents of /boot in a bug report. See, for example, Bug 1768132, Comment 4.

The "machine-id" man page goes on to say:

"the machine ID should be hashed with a cryptographic, keyed hash function, using a fixed, application-specific key."

Version-Release number of selected component (if applicable):
dracut-config-rescue-050-26.git20200316.fc32.x86_64

$ rpm -qf /etc/machine-id
systemd-245~rc1-4.fc32.x86_64

How reproducible:
Always.

Steps to Reproduce:
1. $ ls /boot/*rescue*
2. $ cat /etc/machine-id

Actual results:

The machine ID is exposed in the file names.

Expected results:

Alternative 1: The file names contain a hashed machine ID as recommended in the "machine-id" man page.

Alternative 2: The file names have an informative name, such as:

vmlinuz-0-rescue-5.6.0-0.rc5.git0.2.fc32.x86_64

Additional info:

This is where /etc/machine-id is used in the dracut-config-rescue shell scripts:

$ rpm -ql dracut-config-rescue | xargs fgrep -n '/etc/machine-id'
/etc/kernel/postinst.d/51-dracut-rescue-postinst.sh:10:if [[ ! -f /etc/machine-id ]] || [[ ! -s /etc/machine-id ]]; then
/etc/kernel/postinst.d/51-dracut-rescue-postinst.sh:14:[[ -f /etc/machine-id ]] && read MACHINE_ID < /etc/machine-id
/usr/lib/kernel/install.d/51-dracut-rescue.install:38:elif [[ -f /etc/machine-id ]] ; then
/usr/lib/kernel/install.d/51-dracut-rescue.install:39:    read MACHINE_ID < /etc/machine-id

Comment 1 Steve 2020-03-31 12:25:33 UTC
See, also:

Bug 1768132 - if new kernel version needs new rescue kernel, say so or make it

Comment 2 Steve 2020-04-01 19:45:20 UTC
(In reply to Steve from comment #0)
...
> This is where /etc/machine-id is used in the dracut-config-rescue shell scripts:
...

Grub2 is using /etc/machine-id too:

# rpm -qla grub2\* | xargs fgrep -nr -s '/etc/machine-id'
/usr/sbin/grub2-switch-to-blscfg:184:if [ -f /etc/machine-id ]; then
/usr/sbin/grub2-switch-to-blscfg:185:    MACHINE_ID=$(cat /etc/machine-id)

That shell script is using /etc/machine-id to construct the names of rescue kernels and ".conf" files:

# egrep -n 'vmlinuz-0|rescue\.conf' /usr/sbin/grub2-switch-to-blscfg
264:    if [ -f "/boot/vmlinuz-0-rescue-${MACHINE_ID}" ]; then
265:	mkbls "0-rescue-${MACHINE_ID}" "0" "${bootprefix}" >"${blsdir}/${MACHINE_ID}-0-rescue.conf"

For the record:

$ rpm -qf /usr/sbin/grub2-switch-to-blscfg
grub2-tools-2.04-11.fc32.x86_64

Comment 3 Fedora Program Management 2021-04-29 16:16:09 UTC
This message is a reminder that Fedora 32 is nearing its end of life.
Fedora will stop maintaining and issuing updates for Fedora 32 on 2021-05-25.
It is Fedora's policy to close all bug reports from releases that are no longer
maintained. At that time this bug will be closed as EOL if it remains open with a
Fedora 'version' of '32'.

Package Maintainer: If you wish for this bug to remain open because you
plan to fix it in a currently maintained version, simply change the 'version' 
to a later Fedora version.

Thank you for reporting this issue and we are sorry that we were not 
able to fix it before Fedora 32 is end of life. If you would still like 
to see this bug fixed and are able to reproduce it against a later version 
of Fedora, you are encouraged  change the 'version' to a later Fedora 
version prior this bug is closed as described in the policy above.

Although we aim to fix as many bugs as possible during every release's 
lifetime, sometimes those efforts are overtaken by events. Often a 
more recent Fedora release includes newer upstream software that fixes 
bugs or makes them obsolete.

Comment 4 Ben Cotton 2021-05-25 15:51:36 UTC
Fedora 32 changed to end-of-life (EOL) status on 2021-05-25. Fedora 32 is
no longer maintained, which means that it will not receive any further
security or bug fix updates. As a result we are closing this bug.

If you can reproduce this bug against a currently maintained version of
Fedora please feel free to reopen this bug against that version. If you
are unable to reopen this bug, please file a new report against the
current release. If you experience problems, please add a comment to this
bug.

Thank you for reporting this bug and we are sorry it could not be fixed.

Comment 5 Sergio Basto 2022-12-31 02:58:59 UTC
JFTR this is fixed 

title="Fedora Linux (0-rescue-9b64058eb4c74f9d9a4bd435329809eb) 37 (Thirty Seven)"

cat /etc/machine-id
9b64058eb4c74f9d9a4bd435329809eb


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