Chapter 5. Issues to be aware of for jessie

Table of Contents

5.1. Limitations in security support
5.1.1. Security status of web browsers
5.1.2. Lack of security support for the ecosystem around libv8 and Node.js
5.2. OpenSSH server defaults to "PermitRootLogin without-password"
5.3. Puppet 2.7 / 3.7 compatibility
5.4. PHP 5.6 upgrade has behavioral changes
5.5. Incompatible changes in Apache HTTPD 2.4
5.6. Upgrading installs the new default init system for Jessie
5.6.1. Stricter handling of failing mounts during boot under systemd
5.6.2. Obsolete init-scripts should be purged
5.6.3. Locally modified init-scripts may need to be ported to systemd
5.6.4. Plymouth needed for boot-prompts under systemd boots
5.6.5. Interaction between logind and acpid
5.7. Required kernel config options for Jessie
5.8. Upgrade considerations for LXC hosts and containers
5.8.1. Upgrading LXC guests running on Wheezy hosts
5.8.2. Upgrading LXC guests running on Jessie hosts
5.8.3. Further information
5.9. Manual migration of disks encrypted with LUKS whirlpool (non-standard setups)
5.10. The GNOME desktop requires basic 3D graphics
5.11. The GNOME desktop does not work with the AMD proprietary FGLRX driver
5.12. Changes in the GNOME default keyboard shortcuts
5.13. Changes to default shell of system users provided by base-passwd
5.14. Migration to new KDE E-mail, Calendar, and Contacts (Kontact)
5.15. Missing virtual consoles ("getty"s) with multiple desktop environments
5.16. "VGA signal out of range" / blank screen during boot with grub-pc
5.17. Stricter validation of cron files in crontab
5.18. Change in handling of unreadable module paths by perl

Sometimes, changes introduced in a new release have side-effects we cannot reasonably avoid, or they expose bugs somewhere else. This section documents issues we are aware of. Please also read the errata, the relevant packages' documentation, bug reports and other information mentioned in Section 6.1, “Further reading”.

5.1. Limitations in security support

There are some packages where Debian cannot promise to provide minimal backports for security issues. These are covered in the following subsections.

Note that the package debian-security-support, introduced in Jessie, helps to track security support status of installed packages.

5.1.1. Security status of web browsers

Debian 8 includes several browser engines which are affected by a steady stream of security vulnerabilities. The high rate of vulnerabilities and partial lack of upstream support in the form of long term branches make it very difficult to support these browsers with backported security fixes. Additionally, library interdependencies make it impossible to update to newer upstream releases. Therefore, browsers built upon the webkit, qtwebkit and khtml engines are included in Jessie, but not covered by security support. These browsers should not be used against untrusted websites.

For general web browser use we recommend Iceweasel or Chromium.

Chromium - while built upon the Webkit codebase - is a leaf package, which will be kept up-to-date by rebuilding the current Chromium releases for stable. Iceweasel and Icedove will also be kept up-to-date by rebuilding the current ESR releases for stable.

5.1.2. Lack of security support for the ecosystem around libv8 and Node.js

The Node.js platform is built on top of libv8-3.14, which experiences a high volume of security issues, but there are currently no volunteers within the project or the security team sufficiently interested and willing to spend the large amount of time required to stem those incoming issues.

Unfortunately, this means that libv8-3.14, nodejs, and the associated node-* package ecosystem should not currently be used with untrusted content, such as unsanitized data from the Internet.

In addition, these packages will not receive any security updates during the lifetime of the Jessie release.

5.2. OpenSSH server defaults to "PermitRootLogin without-password"

In an attempt to harden the default setup, the openssh-server configuration will now default to "PermitRootLogin without-password". If you rely on password authentication for the root user, you may be affected by this change.

The openssh-server will attempt to detect such cases and increase the priority of its debconf prompt.

If you want to keep password authentication for the root user, you can also preseed this question by using:

$ echo 'openssh-server openssh-server/permit-root-login boolean true' | debconf-set-selections
    

5.3. Puppet 2.7 / 3.7 compatibility

If you are using Puppet, please be aware that Puppet 3.7 is not backwards compatible with Puppet 2.7. Among other things, the scoping rules have changed and many deprecated constructs have been removed. See the Puppet 3.x release notes for some of the changes, although be aware that there are further changes in 3.7.

Checking the log files of your current puppetmaster for deprecation warnings and resolving all of those warnings before proceeding with the upgrade will make it much easier to complete the upgrade. Alternatively, or additionally, testing the manifests with a tool like Puppet catalog test may also find potential issues prior to the upgrade.

When upgrading a Puppet managed system from Wheezy to Jessie, you must ensure that the corresponding puppetmaster runs at least Puppet version 3.7. If the master is running Wheezy's puppetmaster, the managed Jessie system will not be able to connect to it.

For more information on incompatability changes, please have a look at Telly upgrade issues and "The Angry Guide to Puppet 3".

5.4. PHP 5.6 upgrade has behavioral changes

The upgrade to Jessie includes an upgrade of PHP from 5.4 to 5.6. This may affect any local PHP scripts and you are advised to check those scripts before upgrading. Below are a selected subset of these issues:

  • To prevent man-in-the-middle attacks against encrypted transfers, client streams now verify peer certificates by default.

    As a result of this change, existing code using ssl:// or tls:// stream wrappers (e.g. file_get_contents(), fsockopen(), stream_socket_client()) may no longer connect successfully without manually disabling peer verification via the stream context's "verify_peer" setting.

    For more information about this particular issue, please read this document.

  • PHP changes the handling of case-insensitivity in many cases:

    • All internal case insensitivity handling for class, function, and constant names is done according to ASCII rules. Current locale settings are ignored.

    • The keywords "self", "parent", and "static" are now always case insensitive.

    • The json_decode() function no longer accepts non-lowercase variants of "boolean" values.

  • The logo GUID functions (e.g. php_logo_guid()) have been removed.

  • It is no longer possible to overwrite keys in static scalar arrays. Please see PHP bug 66015 for an example and more information about this particular issue.

  • The mcrypt_encrypt(), mcrypt_decrypt() and mcrypt_{MODE}() functions no longer accept keys or IVs with incorrect sizes. Furthermore an IV is now required if the used block cipher mode requires it.

  • For legal reasons, the JSON implementation bundled with PHP has been replaced with the version provided by the "jsonc" PECL module. Code that makes assumptions about the finer implementation details of the PHP JSON parser may need to be reviewed.

For more information or the full list of potential issues, please have a look at upstream's list of backwards incompatible changes for PHP 5.5 and 5.6.

5.5. Incompatible changes in Apache HTTPD 2.4

[Note]Note

This section only applies to systems which have installed an Apache HTTPD server and configured it manually.

There have been a number of changes to the configuration of the Apache HTTPD server in version 2.4. On the upstream side, the syntax has changed. Notably, the access control directives have changed considerably and will need manual migration to the new directives.

The mod_access_compat module is mentioned in the upstream upgrade guide as a possible alternative to immediate migration. However, the reports suggest it may not always work.

The managing of configuration files has also been changed in the Debian packaging. In particular, all configuration files and sites must now end with ".conf" to be parsed by default. This change also replaces the existing use of /etc/apache2/conf.d/.

[Note]Note

During the upgrade, you may also see warnings about configuration files placed in /etc/apache2/conf.d/, which are provided by packages from Debian. This warning is unavoidable but harmless as the affected packages will move their configuration once their upgrade completes (which will generally happen after the Apache HTTPD emits its warning).

For more information and the full list of changes, please refer to:

  • Upgrading to 2.4 from 2.2 document provided by Apache for the upstream side.

  • The /usr/share/doc/apache2/NEWS.Debian.gz file provided by the apache2 package.

5.6. Upgrading installs the new default init system for Jessie

Jessie ships with systemd-sysv as default init system. This package is installed automatically on upgrades.

If you have a preference for another init such as sysvinit-core or upstart, it is recommended to set up APT pinning prior to the upgrade. This may also be required if you are upgrading LXC containers before the host. In this case, please refer to Section 5.8.1, “Upgrading LXC guests running on Wheezy hosts”.

As an example, to prevent systemd-sysv from being installed during the upgrade, you can create a file called /etc/apt/preferences.d/local-pin-init with the following contents:

Package: systemd-sysv
Pin: release o=Debian
Pin-Priority: -1
  
[Caution]Caution

Be advised that some packages may have degraded behavior or may be lacking features under a non-default init system.

Please note that the upgrade may install packages containing "systemd" in their name even with APT pinning. These alone do not change your init system. To use systemd as your init system, the systemd-sysv package must be installed first.

If APT or aptitude has issues computing an upgrade path with the pin in place, you may be able to help it by manually installing both sysvinit-core and systemd-shim.

5.6.1. Stricter handling of failing mounts during boot under systemd

The new default init system, systemd-sysv, has a stricter handling of failing "auto" mounts during boot compared to sysvinit. If it fails to mount an "auto" mount (without the "nofail" option), systemd will drop to an emergency shell rather than continuing the boot.

We recommend that all removable or "optional" mount points (e.g. non-critical network drives) listed in /etc/fstab either have the "noauto" or the "nofail" option.

5.6.2. Obsolete init-scripts should be purged

If you are upgrading from previous releases, your system may contain obsolete init-scripts provided by (now) removed packages. These scripts may have inaccurate or no dependency metadata, which can lead to dependency cycles in your init configuration.

To avoid this, we recommend that you go and review the list of packages that are in the "rc" ("Removed, but Config-files remain") state, and purge at least all those containing init-scripts.

Please see Section 4.8.1, “Purging removed packages” for details on finding and purging removed packages.

5.6.3. Locally modified init-scripts may need to be ported to systemd

[Note]Note

This section only applies to systems where Debian-provided init scripts have been modified locally.

If you have modified some of the init scripts provided by Debian, please be aware that these may now have been superseded by a systemd unit file or by systemd itself. If you have debsums installed, you can check for locally modified init scripts by using the following shell command.

debsums -c -e | grep ^/etc/init.d
  

Alternatively, the following can be used in the absence of debsums.

  dpkg-query --show -f'${Conffiles}' | sed 's, /,\n/,g' | \
    grep /etc/init.d | awk 'NF,OFS="  " {print $2, $1}' | \
    md5sum --quiet -c

If either command flags any files and their corresponding packages or the systemd now provides an systemd unit file for that service, the systemd unit file will take precedence to your locally modified init script. Depending on the nature of the change, there are different way to perform the migration.

If necessary, it is possible to override the systemd unit file to have it start the sysvinit script. For more information on systemd unit files, please have a look at the following resources.

5.6.4. Plymouth needed for boot-prompts under systemd boots

If your boot is interactive (e.g. needs a password for an encrypted disk), please ensure that you have plymouth installed and configured. Please refer to /usr/share/doc/plymouth/README.Debian for information on how to configure plymouth.

Without plymouth, you may find that your boot prompt disappears. Reports suggest that the cryptsetup prompt still accepts input despite not being visible. Should you experience this issue, typing the correct password may still work.

5.6.5. Interaction between logind and acpid

ACPI events can be handled by logind or acpid. In case both services are configured to handle events in different ways, this can lead to undesired results.

We recommend to migrate any non-default settings to logind and uninstall acpid. Alternativly it is also possible to configure logind to ignore ACPI events by adding:

    HandlePowerKey=ignore
    HandleSuspendKey=ignore
    HandleHibernateKey=ignore
    HandleLidSwitch=ignore

to /etc/systemd/logind.conf. Note that this might change behaviour of desktop environments relying on logind.

5.7. Required kernel config options for Jessie

[Note]Note

This section is only for people who compile their own kernel. If you use the kernels compiled by Debian, you can disregard this section.

The following kernel configuration options are now either required or recommended for Jessie (in addition to existing ones from previous releases):

# Required for udev
CONFIG_DEVTMPFS=y
# Required for *some* systemd services
CONFIG_DEVPTS_MULTIPLE_INSTANCES=y
# Required by "bluez" (GNOME)
CONFIG_BT=y
# Required for cups + systemd.
CONFIG_PPDEV=y

The systemd services which require CONFIG_DEVPTS_MULTIPLE_INSTANCES=y will typically contain at least one of the following directives:

PrivateTmp=yes
PrivateDevices=yes
PrivateNetwork=yes
ProtectSystem=yes
  

If you do not use systemd, or can assert that none of the systemd services will use the above directives, the config option might not be required for your particular system.

For more information about the requirements, please refer to the section called "REQUIREMENTS" in the README file for the package systemd.

5.8. Upgrade considerations for LXC hosts and containers

[Note]Note

This section only applies to systems that have LXC containers and hosts. Normal end user systems usually do not have these.

The upgrade from Wheezy to Jessie will migrate your system to the systemd init system by default (see Section 5.6, “Upgrading installs the new default init system for Jessie”).

When upgrading an LXC container or an LXC virtual machine, this will have different consequences depending on whether the host system has already been upgraded to Jessie or not.

5.8.1. Upgrading LXC guests running on Wheezy hosts

If you are upgrading an LXC guest container that is running on a Wheezy host system, then you will need to prevent the guest from being automatically migrated to systemd. You prevent the migration via pinning, as described in Section 5.6, “Upgrading installs the new default init system for Jessie”.

This is required as the Wheezy host lacks functionality to boot a system running systemd.

You should be able to switch over to systemd inside the LXC guest once you have upgraded the host system to Jessie. See the next paragraph for things that need to be adapted on Jessie hosts.

5.8.2. Upgrading LXC guests running on Jessie hosts

In order to be able to boot LXC guests with systemd, you need to adapt your LXC container configuration. The container configuration can usually be found in /var/lib/lxc/CONTAINER_NAME/config You need to add the following two settings to the configuration:

lxc.autodev = 1
lxc.kmsg = 0

5.8.3. Further information

You can find further information on LXC in Debian in the Debian wiki.

5.9. Manual migration of disks encrypted with LUKS whirlpool (non-standard setups)

[Note]Note

This section is only for people who have set up LUKS encrypted disks themselves using the whirlpool hash. The debian-installer has never supported creating such disks.

If you have manually set up an encrypted disk with LUKS whirlpool, you will need to migrate it manually to a stronger hash. You can check if your disk is using whirlpool by using the following command:

    # /sbin/cryptsetup luksDump <disk-device> | grep -i whirlpool
  

For more information on migrating, please see item "8.3 Gcrypt 1.6.x and later break Whirlpool" of the cryptsetup FAQ.

[Caution]Caution

If you have such a disk, cryptsetup will refuse to decrypt it by default. If your rootdisk or other system disks (e.g. /usr) are encrypted with whirlpool, you should migrate them prior to the first reboot after upgrading cryptsetup.

5.10. The GNOME desktop requires basic 3D graphics

The GNOME 3.14 desktop in Jessie no longer has fallback support for machines without basic 3D graphics. To run properly, it needs either a recent enough PC (any PC built in the last 10 years should have the required SSE2 support) or, for architectures other than i386 and amd64, a 3D-accelerated graphics adapter with EGL drivers.

5.11. The GNOME desktop does not work with the AMD proprietary FGLRX driver

Unlike other OpenGL drivers, the AMD FGLRX driver for Radeon adapters does not support the EGL interface. As such, several GNOME applications, including the core of the GNOME desktop, will not start at all when this driver is in use.

It is recommended to use the free radeon driver, which is the default in jessie, instead.

5.12. Changes in the GNOME default keyboard shortcuts

The default keyboard shortcuts in the GNOME desktop have changed in order to match more closely those of some other operating systems.

Shortcut settings previously modified by the user will be preserved upon upgrade. These settings can still be configured from the GNOME control center, accessible from the top right menu by clicking on the "settings" icon.

5.13. Changes to default shell of system users provided by base-passwd

The upgrade of the base-passwd package will reset the shell of some system users to the "nologin" shell. This includes the following users:

  • daemon

  • bin

  • sys

  • games

  • man

  • lp

  • mail

  • news

  • uucp

  • proxy

  • www-data

  • backup

  • list

  • irc

  • gnats

  • nobody

If your local setup requires that any of these users have a shell, you should say no to migrating, or migrate and then change the shell of the corresponding users. Notable examples include local backups done via the "backup" user with "ssh-key" authentication.

[Caution]Caution

The migration will happen automatically if your debconf question priority is "high" or above.

If you know you want to keep the current shell of a given user, you can preseed the questions by using the following:

    echo 'base-passwd base-passwd/system/username/shell/current-shell-mangled/_usr_sbin_nologin boolean false' | debconf-set-selections
  

Where username is the name of the user in question and current-shell-mangled is the mangled name of the shell. The mangling is done by replacing all characters other than alphanumerics, dashes, and underscores with underscores. E.g. /bin/bash becomes _bin_bash.

5.14. Migration to new KDE E-mail, Calendar, and Contacts (Kontact)

The Kontact Personal Information Management system has received a major upgrade. The new version makes much greater use of metadata indexing and each user's data must be migrated into these new indices.

E-mail, calendar events, and addressbook contacts are automatically migrated when the user logs in and the relevant component is started. Some advanced settings such as e-mail filters and custom templates require manual intervention. Further details and troubleshooting suggestions are collected on the Debian Wiki.

5.15. Missing virtual consoles ("getty"s) with multiple desktop environments

If you have multiple desktop environments installed, you may experience that none of the "virtual consoles" show a login prompt.

This issue seems to occur when plymouth, systemd, and GNOME are all installed. This issue is reported as Debian Bug#766462.

It has been reported that removing the "splash" argument from the kernel command-line may work around the issue. Please see /etc/default/grub and remember to run update-grub after updating the file.

5.16. "VGA signal out of range" / blank screen during boot with grub-pc

There is a compatibility issue in grub-pc with older graphics cards (e.g. the "ATI Rage 128 Pro Ultra TR") that can cause it to show a blank screen during boot. The display may issue a "VGA signal out of range" message (or something similar).

A simple work around is to set GRUB_TERMINAL=console in /etc/default/grub.

5.17. Stricter validation of cron files in crontab

The crontab program is now more strict and may refuse to save a changed cron file if it is invalid. If you experience issues with crontab -e, please review your crontab for existing mistakes.

5.18. Change in handling of unreadable module paths by perl

From version 5.18 (and 5.20, which is included in Jessie), Perl will exit with a fatal error if it encounters unreadable module paths in @INC. The previous behavior was to skip such entries. It is recommended to check the contents of @INC in your environment for directories which are not world-readable, and take appropriate action.

You can see the default @INC for Perl by running perl -V.