A Linux kernel security updates for Ubuntu Linux are available over live patch.

LSN-0065-1: Linux kernel vulnerability

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Kernel Live Patch Security Notice 0065-1
April 09, 2020

linux vulnerability
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A security issue affects these releases of Ubuntu:

| Series | Base kernel | Arch | flavors | |------------------+--------------+----------+------------------|
| Ubuntu 18.04 LTS | 4.15.0 | amd64 | aws | | Ubuntu 18.04 LTS | 4.15.0 | amd64 | generic | | Ubuntu 18.04 LTS | 4.15.0 | amd64 | lowlatency | | Ubuntu 18.04 LTS | 4.15.0 | amd64 | oem | | Ubuntu 18.04 LTS | 5.0.0 | amd64 | azure | | Ubuntu 18.04 LTS | 5.0.0 | amd64 | gcp | | Ubuntu 14.04 LTS | 4.4.0 | amd64 | generic | | Ubuntu 14.04 LTS | 4.4.0 | amd64 | lowlatency | | Ubuntu 16.04 LTS | 4.4.0 | amd64 | aws | | Ubuntu 16.04 LTS | 4.4.0 | amd64 | generic | | Ubuntu 16.04 LTS | 4.4.0 | amd64 | lowlatency | | Ubuntu 16.04 LTS | 4.15.0 | amd64 | azure | | Ubuntu 16.04 LTS | 4.15.0 | amd64 | generic | | Ubuntu 16.04 LTS | 4.15.0 | amd64 | lowlatency |
Summary:

Several security issues were fixed in the kernel.

Software Description:
- linux: Linux kernel

Details:

Andrew Honig reported a flaw in the way KVM (Kernel-based Virtual Machine) emulated the IOAPIC. A privileged guest user could exploit this flaw to read host memory or cause a denial of service (crash the host). (CVE-2013-1798)

It was discovered that the KVM implementation in the Linux kernel, when paravirtual TLB flushes are enabled in guests, the hypervisor in some situations could miss deferred TLB flushes or otherwise mishandle them. An attacker in a guest VM could use this to expose sensitive information (read memory from another guest VM). (CVE-2019-3016)

Al Viro discovered that the vfs layer in the Linux kernel contained a use- after-free vulnerability. A local attacker could use this to cause a denial of service (system crash) or possibly expose sensitive information (kernel memory). (CVE-2020-8428)

Update instructions:

The problem can be corrected by updating your livepatches to the following versions:

| Kernel | Version | flavors | |--------------------------+----------+--------------------------|
| 4.4.0-168.197 | 65.1 | generic, lowlatency | | 4.4.0-168.197~14.04.1 | 65.1 | lowlatency, generic | | 4.4.0-169.198 | 65.1 | generic, lowlatency | | 4.4.0-169.198~14.04.1 | 65.1 | lowlatency, generic | | 4.4.0-170.199 | 65.1 | lowlatency, generic | | 4.4.0-170.199~14.04.1 | 65.1 | lowlatency, generic | | 4.4.0-171.200 | 65.1 | lowlatency, generic | | 4.4.0-171.200~14.04.1 | 65.1 | generic, lowlatency | | 4.4.0-173.203 | 65.1 | generic, lowlatency | | 4.4.0-173.203~14.04.1 | 65.1 | generic, lowlatency | | 4.4.0-174.204 | 65.1 | lowlatency, generic | | 4.4.0-174.204~14.04.1 | 65.1 | generic, lowlatency | | 4.4.0-176.206 | 65.1 | lowlatency, generic | | 4.4.0-1098.109 | 65.1 | aws | | 4.4.0-1099.110 | 65.1 | aws | | 4.4.0-1101.112 | 65.1 | aws | | 4.4.0-1102.113 | 65.1 | aws | | 4.15.0-69.78 | 65.1 | generic, lowlatency | | 4.15.0-69.78~16.04.1 | 65.1 | lowlatency, generic | | 4.15.0-70.79 | 65.1 | lowlatency, generic | | 4.15.0-70.79~16.04.1 | 65.1 | generic, lowlatency | | 4.15.0-72.81 | 65.1 | generic, lowlatency | | 4.15.0-72.81~16.04.1 | 65.1 | generic, lowlatency | | 4.15.0-74.83~16.04.1 | 65.1 | lowlatency, generic | | 4.15.0-74.84 | 65.1 | generic, lowlatency | | 4.15.0-76.86 | 65.1 | generic, lowlatency | | 4.15.0-76.86~16.04.1 | 65.1 | lowlatency, generic | | 4.15.0-88.88 | 65.1 | generic, lowlatency | | 4.15.0-88.88~16.04.1 | 65.1 | lowlatency, generic | | 4.15.0-91.92 | 65.1 | lowlatency, generic | | 4.15.0-91.92~16.04.1 | 65.1 | generic, lowlatency | | 4.15.0-1054.56 | 65.1 | aws | | 4.15.0-1056.58 | 65.1 | aws | | 4.15.0-1057.59 | 65.1 | aws | | 4.15.0-1058.60 | 65.1 | aws | | 4.15.0-1060.62 | 65.1 | aws | | 4.15.0-1063.67 | 65.1 | aws | | 4.15.0-1063.68 | 65.1 | azure | | 4.15.0-1063.72 | 65.1 | oem | | 4.15.0-1064.69 | 65.1 | azure | | 4.15.0-1064.73 | 65.1 | oem | | 4.15.0-1065.75 | 65.1 | oem | | 4.15.0-1066.71 | 65.1 | azure | | 4.15.0-1066.76 | 65.1 | oem | | 4.15.0-1067.72 | 65.1 | azure | | 4.15.0-1067.77 | 65.1 | oem | | 4.15.0-1069.74 | 65.1 | azure | | 4.15.0-1069.79 | 65.1 | oem | | 4.15.0-1071.76 | 65.1 | azure | | 4.15.0-1073.83 | 65.1 | oem | | 4.15.0-1075.80 | 65.1 | azure | | 4.15.0-1076.86 | 65.1 | oem | | 5.0.0-1025.26~18.04.1 | 65.1 | gcp | | 5.0.0-1025.27~18.04.1 | 65.1 | azure | | 5.0.0-1026.27~18.04.1 | 65.1 | gcp | | 5.0.0-1027.29~18.04.1 | 65.1 | azure | | 5.0.0-1028.29~18.04.1 | 65.1 | gcp | | 5.0.0-1028.30~18.04.1 | 65.1 | azure | | 5.0.0-1029.30~18.04.1 | 65.1 | gcp | | 5.0.0-1029.31~18.04.1 | 65.1 | azure |
Support Information:

Kernels older than the levels listed below do not receive livepatch updates. Please upgrade your kernel as soon as possible.

| Series | Version | Flavors | |------------------+------------------+--------------------------|
| Ubuntu 18.04 LTS | 4.15.0-1054 | aws | | Ubuntu 16.04 LTS | 4.4.0-1098 | aws | | Ubuntu 18.04 LTS | 5.0.0-1025 | azure | | Ubuntu 16.04 LTS | 4.15.0-1063 | azure | | Ubuntu 18.04 LTS | 4.15.0-69 | generic lowlatency | | Ubuntu 18.04 LTS | 5.0.0-1025 | gcp | | Ubuntu 16.04 LTS | 4.15.0-69 | generic lowlatency | | Ubuntu 14.04 LTS | 4.4.0-168 | generic lowlatency | | Ubuntu 18.04 LTS | 4.15.0-1063 | oem | | Ubuntu 16.04 LTS | 4.4.0-168 | generic lowlatency |
References:
CVE-2013-1798, CVE-2019-3016, CVE-2020-8428