CVE-2018-5748

qemu/qemu_monitor.c in libvirt allows attackers to cause a denial of service (memory consumption) via a large QEMU reply.

Updated libvirt packages fix security vulnerabilities:

In virsh, the hostname could crafted maliciously with ssh arguments, which would be passed to ssh (bsc#1053600).

The default_tls_x509_verify (and related) parameters in qemu.conf control whether the TLS servers in QEMU request & verify certificates from clients. This works as a simple access control system for QEMU servers by requiring the CA to issue certs to permitted clients. This use of client certificates is disabled by default, since it requires extra work to issue client certificates. Unfortunately the libvirt code was using these configuration parameters when setting up both TLS clients and servers in QEMU. The result was that TLS clients for character devices and disk devices had verification turned off, meaning they would ignore any errors while validating the server certificate (CVE-2017-1000256).

An industry-wide issue was found in the way many modern microprocessor designs have implemented speculative execution of instructions (a commonly used performance optimization). There are three primary variants of the issue which differ in the way the speculative execution can be exploited. Variant CVE-2017-5715 triggers the speculative execution by utilizing branch target injection. It relies on the presence of a precisely-defined instruction sequence in the privileged code as well as the fact that memory accesses may cause allocation into the microprocessor's data cache even for speculatively executed instructions that never actually commit (retire). As a result, an unprivileged attacker could use this flaw to cross the syscall and guest/host boundaries and read privileged memory by conducting targeted cache side-channel attacks (CVE-2017-5715).

qemu/qemu_monitor.c in libvirt allows attackers to cause a denial of service (memory consumption) via a large QEMU reply (CVE-2018-5748).

It was discovered libvirt does not properly determine the hostname on LXC container startup, which allows local guest OS users to bypass an intended container protection mechanism and execute arbitrary commands via a crafted NSS module (CVE-2018-6764).

These are all security issues fixed in the libvirt-7.7.0-2.1 package on the GA media of openSUSE Tumbleweed.

This update for libvirt provides several fixes.

This security issue was fixed:

• CVE-2018-5748: Prevent resource exhaustion via qemuMonitorIORead() method which allowed to cause DoS (bsc#1076500).

These security issues were fixed:

• Add a qemu hook script providing functionality similar to Xen's block-dmmd script. (fate#324177)
• schema: Make disk driver name attribute optional. (bsc#1073973)
• virt-create-rootfs: Handle all SLE 12 versions. (bsc#1072887)
• libvirt-guests: Fix the 'stop' operation when action is 'suspend'. (bsc#1070130)
• s390: Fix missing host cpu model info. (bsc#1065766)
• cpu: Add new EPYC CPU model. (bsc#1052825, fate#324038)
• pci: Fix the detection of the link's maximum speed. (bsc#1064947)
• nodedev: Increase the netlink socket buffer size. (bsc#1035442)
• storage: Fix a race between the volume creation and the pool refresh. (bsc#1062571)
• daemon: Drop the minsize directive from hypervisor logrotate files. (bsc#1062760)

This update for libvirt provides several fixes.

This security issue was fixed:

• CVE-2018-5748: Prevent resource exhaustion via qemuMonitorIORead() method which allowed to cause DoS (bsc#1076500).

These security issues were fixed:

• Add a qemu hook script providing functionality similar to Xen's block-dmmd script. (fate#324177)
• schema: Make disk driver name attribute optional. (bsc#1073973)
• virt-create-rootfs: Handle all SLE 12 versions. (bsc#1072887)
• libvirt-guests: Fix the 'stop' operation when action is 'suspend'. (bsc#1070130)

This update for libvirt fixes the following issues:

Security issues fixed:

• CVE-2017-5715: Fixes for speculative side channel attacks aka 'SpectreAttack' (var2) (bsc#1079869).
• CVE-2018-1064: Fixed denial of service when reading from guest agent (bsc#1083625).
• CVE-2018-5748: Fixed possible denial of service when reading from QEMU monitor (bsc#1076500).

Non-security issues fixed:

• bsc#1083061: Fixed 'dumpxml --migratable' exports domain id in output on SLES11 SP4.
• bsc#1055365: Improve performance when listing hundreds of interfaces.

This update for libvirt fixes the following issues:

Security issues fixed:

• CVE-2017-5715: Spectre fixes for libvirt (bsc#1079869, bsc#1088147, bsc#1087887).
• CVE-2018-1064: Avoid denial of service reading from QEMU guest agent (bsc#1083625).
• CVE-2018-5748: Avoid denial of service reading from QEMU monitor (bsc#1076500).

Bug fixes:

• bsc#1025340: Use xend for nodeGetFreeMemory API.
• bsc#960742: Allow read access to script directories in libvirtd AppArmor profile.
• bsc#936233: Introduce qemuDomainDefCheckABIStability.

This update for libvirt fixes the following issues:

Security issues fixed:

• CVE-2017-5715: Fixes for speculative side channel attacks aka 'SpectreAttack' (var2) (bsc#1079869).
• CVE-2018-3639: Add support for 'ssbd' and 'virt-ssbd' CPUID feature bits to address V4 Speculative Store Bypass aka 'Memory Disambiguation' (bsc#1092885).
• CVE-2018-1064: Fix denial of service problem during reading from guest agent (bsc#1083625).
• CVE-2018-5748: Fix resource exhaustion via qemuMonitorIORead() method (bsc#1076500).

This update for libvirt fixes the following issues:

Security issues fixed:

• CVE-2018-3639: Add support for 'ssbd' and 'virt-ssbd' CPUID feature bits to address V4 Speculative Store Bypass aka 'Memory Disambiguation' (bsc#1092885).
• CVE-2018-1064: Fix denial of service problem during reading from guest agent (bsc#1083625).
• CVE-2018-5748: Fix resource exhaustion via qemuMonitorIORead() method (bsc#1076500).
• CVE-2016-5008: Fix that an empty VNC password disables authentication (bsc#987527).
• CVE-2017-5715: Fix speculative side channel attacks aka 'SpectreAttack' (var2) (bsc#1079869).

Bug fixes:

• bsc#980558: Fix NUMA node memory allocation.
• bsc#968483: Restart daemons in %posttrans after connection drivers.
• bsc#897352: Systemd fails to ignore LSB services.
• bsc#956298: virsh domxml-to-native causes segfault of libvirtd.
• bsc#964465: libvirtd.service causes systemd warning about xencommons service.
• bsc#954872: Script block-dmmd not working as expected.
• bsc#854343: libvirt installation run inappropriate systemd restart.

Vivian Zhang and Christoph Anton Mitterer discovered that libvirt incorrectly disabled password authentication when the VNC password was set to an empty string. A remote attacker could possibly use this issue to bypass authentication, contrary to expectations. This issue only affected Ubuntu 14.04 LTS and Ubuntu 16.04 LTS. (CVE-2016-5008)

Daniel P. Berrange discovered that libvirt incorrectly handled validating SSL/TLS certificates. A remote attacker could possibly use this issue to obtain sensitive information. This issue only affected Ubuntu 17.10. (CVE-2017-1000256)

Daniel P. Berrange and Peter Krempa discovered that libvirt incorrectly handled large QEMU replies. An attacker could possibly use this issue to cause libvirt to crash, resulting in a denial of service. (CVE-2018-5748)

Pedro Sampaio discovered that libvirt incorrectly handled the libnss_dns.so module. An attacker in a libvirt_lxc session could possibly use this issue to execute arbitrary code. This issue only affected Ubuntu 16.04 LTS and Ubuntu 17.10. (CVE-2018-6764)