CVE-2018-6954

systemd-tmpfiles in systemd through 237 mishandles symlinks present in non-terminal path components, which allows local users to obtain ownership of arbitrary files via vectors involving creation of a directory and a file under that directory, and later replacing that directory with a symlink. This occurs even if the fs.protected_symlinks sysctl is turned on.

This update for systemd provides the following fixes:

Security issues fixed:

• CVE-2018-16864, CVE-2018-16865: Fixed two memory corruptions through attacker-controlled alloca()s (bsc#1120323)
• CVE-2018-16866: Fixed an information leak in journald (bsc#1120323)
• CVE-2018-6954: Fix mishandling of symlinks present in non-terminal path components (bsc#1080919)
• Fixed an issue during system startup in relation to encrypted swap disks (bsc#1119971)

Non-security issues fixed:

• pam_systemd: Fix 'Cannot create session: Already running in a session' (bsc#1111498)
• systemd-vconsole-setup: vconsole setup fails, fonts will not be copied to tty (bsc#1114933)
• systemd-tmpfiles-setup: symlinked /tmp to /var/tmp breaking multiple units (bsc#1045723)
• Fixed installation issue with /etc/machine-id during update (bsc#1117063)
• btrfs: qgroups are assigned to parent qgroups after reboot (bsc#1093753)
• logind: Stop managing VT switches if no sessions are registered on that VT. (bsc#1101591)
• udev: Downgrade message when settting inotify watch up fails. (bsc#1005023)
• udev: Ignore the exit code of systemd-detect-virt for memory hot-add. In SLE-12-SP3, 80-hotplug-cpu-mem.rules has a memory hot-add rule that uses systemd-detect-virt to detect non-zvm environment. The systemd-detect-virt returns exit failure code when it detected none state. The exit failure code causes that the hot-add memory block can not be set to online. (bsc#1076696)

This update was imported from the SUSE:SLE-15:Update update project.

These are all security issues fixed in the libsystemd0-249.4-2.2 package on the GA media of openSUSE Tumbleweed.

This update for systemd provides the following fixes:

Security issues fixed:

• CVE-2018-16864, CVE-2018-16865: Fixed two memory corruptions through attacker-controlled alloca()s (bsc#1120323)
• CVE-2018-16866: Fixed an information leak in journald (bsc#1120323)
• CVE-2018-6954: Fix mishandling of symlinks present in non-terminal path components (bsc#1080919)
• Fixed an issue during system startup in relation to encrypted swap disks (bsc#1119971)

Non-security issues fixed:

• pam_systemd: Fix 'Cannot create session: Already running in a session' (bsc#1111498)
• systemd-vconsole-setup: vconsole setup fails, fonts will not be copied to tty (bsc#1114933)
• systemd-tmpfiles-setup: symlinked /tmp to /var/tmp breaking multiple units (bsc#1045723)
• Fixed installation issue with /etc/machine-id during update (bsc#1117063)
• btrfs: qgroups are assigned to parent qgroups after reboot (bsc#1093753)
• logind: Stop managing VT switches if no sessions are registered on that VT. (bsc#1101591)
• udev: Downgrade message when settting inotify watch up fails. (bsc#1005023)
• udev: Ignore the exit code of systemd-detect-virt for memory hot-add. In SLE-12-SP3, 80-hotplug-cpu-mem.rules has a memory hot-add rule that uses systemd-detect-virt to detect non-zvm environment. The systemd-detect-virt returns exit failure code when it detected none state. The exit failure code causes that the hot-add memory block can not be set to online. (bsc#1076696)

This update for systemd fixes the following issues:

Security issues fixed:

• CVE-2018-6954: Fixed a vulnerability in the symlink handling of systemd-tmpfiles which allowed a local user to obtain ownership of arbitrary files (bsc#1080919).
• CVE-2019-3842: Fixed a vulnerability in pam_systemd which allowed a local user to escalate privileges (bsc#1132348).
• CVE-2019-6454: Fixed a denial of service caused by long dbus messages (bsc#1125352).

Non-security issues fixed:

• systemd-coredump: generate a stack trace of all core dumps (jsc#SLE-5933)
• udevd: notify when max number value of children is reached only once per batch of events (bsc#1132400)
• sd-bus: bump message queue size again (bsc#1132721)
• core: only watch processes when it's really necessary (bsc#955942 bsc#1128657)
• rules: load drivers only on 'add' events (bsc#1126056)
• sysctl: Don't pass null directive argument to '%s' (bsc#1121563)
• Do not automatically online memory on s390x (bsc#1127557)

Jann Horn discovered that unit_deserialize incorrectly handled status messages above a certain length. A local attacker could potentially exploit this via NotifyAccess to inject arbitrary state across re-execution and obtain root privileges. (CVE-2018-15686)

Jann Horn discovered a race condition in chown_one(). A local attacker could potentially exploit this by setting arbitrary permissions on certain files to obtain root privileges. This issue only affected Ubuntu 18.04 LTS and Ubuntu 18.10. (CVE-2018-15687)

It was discovered that systemd-tmpfiles mishandled symlinks in non-terminal path components. A local attacker could potentially exploit this by gaining ownership of certain files to obtain root privileges. This issue only affected Ubuntu 16.04 LTS and Ubuntu 18.04 LTS. (CVE-2018-6954)

USN-3816-1 fixed several vulnerabilities in systemd. However, the fix for CVE-2018-6954 was not sufficient. This update provides the remaining fixes.

We apologize for the inconvenience.

Original advisory details:

Jann Horn discovered that unit_deserialize incorrectly handled status messages above a certain length. A local attacker could potentially exploit this via NotifyAccess to inject arbitrary state across re-execution and obtain root privileges. (CVE-2018-15686)

Jann Horn discovered a race condition in chown_one(). A local attacker could potentially exploit this by setting arbitrary permissions on certain files to obtain root privileges. This issue only affected Ubuntu 18.04 LTS and Ubuntu 18.10. (CVE-2018-15687)

It was discovered that systemd-tmpfiles mishandled symlinks in non-terminal path components. A local attacker could potentially exploit this by gaining ownership of certain files to obtain root privileges. This issue only affected Ubuntu 16.04 LTS and Ubuntu 18.04 LTS. (CVE-2018-6954)