Race Condition Affecting kernel-default-man package, versions <4.12.14-150.52.1


Severity

Recommended
0.0
high
0
10

Based on SUSE Linux Enterprise Server security rating.

Threat Intelligence

EPSS
0.05% (25th percentile)

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  • Snyk IDSNYK-SLES150-KERNELDEFAULTMAN-2731720
  • published14 Apr 2022
  • disclosed18 Jun 2020

Introduced: 18 Jun 2020

CVE-2020-8834  (opens in a new tab)
CWE-362  (opens in a new tab)

How to fix?

Upgrade SLES:15.0 kernel-default-man to version 4.12.14-150.52.1 or higher.

NVD Description

Note: Versions mentioned in the description apply only to the upstream kernel-default-man package and not the kernel-default-man package as distributed by SLES. See How to fix? for SLES:15.0 relevant fixed versions and status.

KVM in the Linux kernel on Power8 processors has a conflicting use of HSTATE_HOST_R1 to store r1 state in kvmppc_hv_entry plus in kvmppc_{save,restore}_tm, leading to a stack corruption. Because of this, an attacker with the ability run code in kernel space of a guest VM can cause the host kernel to panic. There were two commits that, according to the reporter, introduced the vulnerability: f024ee098476 ("KVM: PPC: Book3S HV: Pull out TM state save/restore into separate procedures") 87a11bb6a7f7 ("KVM: PPC: Book3S HV: Work around XER[SO] bug in fake suspend mode") The former landed in 4.8, the latter in 4.17. This was fixed without realizing the impact in 4.18 with the following three commits, though it's believed the first is the only strictly necessary commit: 6f597c6b63b6 ("KVM: PPC: Book3S PR: Add guest MSR parameter for kvmppc_save_tm()/kvmppc_restore_tm()") 7b0e827c6970 ("KVM: PPC: Book3S HV: Factor fake-suspend handling out of kvmppc_save/restore_tm") 009c872a8bc4 ("KVM: PPC: Book3S PR: Move kvmppc_save_tm/kvmppc_restore_tm to separate file")

CVSS Scores

version 3.1