gsd-2020-8834
Vulnerability from gsd
Modified
2023-12-13 01:21
Details
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")
Aliases
Aliases
CVE-2020-8834


To clipboard 

{
  "GSD": {
    "alias": "CVE-2020-8834",
    "description": "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\u0027s 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\")",
    "id": "GSD-2020-8834",
    "references": [
      "https://www.suse.com/security/cve/CVE-2020-8834.html",
      "https://access.redhat.com/errata/RHSA-2020:2854",
      "https://ubuntu.com/security/CVE-2020-8834"
    ]
  },
  "gsd": {
    "metadata": {
      "exploitCode": "unknown",
      "remediation": "unknown",
      "reportConfidence": "confirmed",
      "type": "vulnerability"
    },
    "osvSchema": {
      "aliases": [
        "CVE-2020-8834"
      ],
      "details": "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\u0027s 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\")",
      "id": "GSD-2020-8834",
      "modified": "2023-12-13T01:21:54.066797Z",
      "schema_version": "1.4.0"
    }
  },
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        "DATE_PUBLIC": "2020-04-06T16:00:00.000Z",
        "ID": "CVE-2020-8834",
        "STATE": "PUBLIC",
        "TITLE": "Linux kernel KVM Power8 conflicting use of  HSTATE_HOST_R1"
      },
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                    "version": {
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                          "platform": "PPC Power8",
                          "version_affected": "\u003e=",
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                          "platform": "PPC Power8",
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          "value": "Gustavo Romero"
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            "value": "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\u0027s 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\")"
          }
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          "baseSeverity": "MEDIUM",
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      },
      "solution": [
        {
          "lang": "eng",
          "value": "Apply the following three Linux kernel commits, though possibly only the first commit is strictly necessary:                                                                                           \n                                                                                                                                                             \n  6f597c6b63b6 (\"KVM: PPC: Book3S PR: Add guest MSR parameter for kvmppc_save_tm()/kvmppc_restore_tm()\")\n  7b0e827c6970 (\"KVM: PPC: Book3S HV: Factor fake-suspend handling out of kvmppc_save/restore_tm\")\n  009c872a8bc4 (\"KVM: PPC: Book3S PR: Move kvmppc_save_tm/kvmppc_restore_tm to separate file\") "
        }
      ],
      "source": {
        "defect": [
          "https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1867717"
        ],
        "discovery": "EXTERNAL"
      }
    },
    "nvd.nist.gov": {
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          "impactScore": 4.0
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      },
      "lastModifiedDate": "2022-10-07T15:43Z",
      "publishedDate": "2020-04-09T22:15Z"
    }
  }
}


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