msrc_cve-2021-26932
Vulnerability from csaf_microsoft
Published
2021-02-02 00:00
Modified
2021-02-26 00:00
Summary
An issue was discovered in the Linux kernel 3.2 through 5.10.16 as used by Xen. Grant mapping operations often occur in batch hypercalls where a number of operations are done in a single hypercall the success or failure of each one is reported to the backend driver and the backend driver then loops over the results performing follow-up actions based on the success or failure of each operation. Unfortunately when running in PV mode the Linux backend drivers mishandle this: Some errors are ignored effectively implying their success from the success of related batch elements. In other cases errors resulting from one batch element lead to further batch elements not being inspected and hence successful ones to not be possible to properly unmap upon error recovery. Only systems with Linux backends running in PV mode are vulnerable. Linux backends run in HVM / PVH modes are not vulnerable. This affects arch/*/xen/p2m.c and drivers/xen/gntdev.c.

Notes

Additional Resources
To determine the support lifecycle for your software, see the Microsoft Support Lifecycle: https://support.microsoft.com/lifecycle
Disclaimer
The information provided in the Microsoft Knowledge Base is provided \"as is\" without warranty of any kind. Microsoft disclaims all warranties, either express or implied, including the warranties of merchantability and fitness for a particular purpose. In no event shall Microsoft Corporation or its suppliers be liable for any damages whatsoever including direct, indirect, incidental, consequential, loss of business profits or special damages, even if Microsoft Corporation or its suppliers have been advised of the possibility of such damages. Some states do not allow the exclusion or limitation of liability for consequential or incidental damages so the foregoing limitation may not apply.


To clipboard 

{
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        "title": "Additional Resources"
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        "text": "The information provided in the Microsoft Knowledge Base is provided \\\"as is\\\" without warranty of any kind. Microsoft disclaims all warranties, either express or implied, including the warranties of merchantability and fitness for a particular purpose. In no event shall Microsoft Corporation or its suppliers be liable for any damages whatsoever including direct, indirect, incidental, consequential, loss of business profits or special damages, even if Microsoft Corporation or its suppliers have been advised of the possibility of such damages. Some states do not allow the exclusion or limitation of liability for consequential or incidental damages so the foregoing limitation may not apply.",
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        "summary": "CVE-2021-26932 An issue was discovered in the Linux kernel 3.2 through 5.10.16 as used by Xen. Grant mapping operations often occur in batch hypercalls where a number of operations are done in a single hypercall the success or failure of each one is reported to the backend driver and the backend driver then loops over the results performing follow-up actions based on the success or failure of each operation. Unfortunately when running in PV mode the Linux backend drivers mishandle this: Some errors are ignored effectively implying their success from the success of related batch elements. In other cases errors resulting from one batch element lead to further batch elements not being inspected and hence successful ones to not be possible to properly unmap upon error recovery. Only systems with Linux backends running in PV mode are vulnerable. Linux backends run in HVM / PVH modes are not vulnerable. This affects arch/*/xen/p2m.c and drivers/xen/gntdev.c. - VEX",
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        {
          "category": "self",
          "summary": "CVE-2021-26932 An issue was discovered in the Linux kernel 3.2 through 5.10.16 as used by Xen. Grant mapping operations often occur in batch hypercalls where a number of operations are done in a single hypercall the success or failure of each one is reported to the backend driver and the backend driver then loops over the results performing follow-up actions based on the success or failure of each operation. Unfortunately when running in PV mode the Linux backend drivers mishandle this: Some errors are ignored effectively implying their success from the success of related batch elements. In other cases errors resulting from one batch element lead to further batch elements not being inspected and hence successful ones to not be possible to properly unmap upon error recovery. Only systems with Linux backends running in PV mode are vulnerable. Linux backends run in HVM / PVH modes are not vulnerable. This affects arch/*/xen/p2m.c and drivers/xen/gntdev.c. - VEX",
          "url": "https://msrc.microsoft.com/csaf/vex/2021/msrc_cve-2021-26932.json"
        }
      ],
      "remediations": [
        {
          "category": "vendor_fix",
          "date": "2021-02-26T00:00:00.000Z",
          "details": "-:Security Update:https://learn.microsoft.com/en-us/azure/azure-linux/tutorial-azure-linux-upgrade",
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      "scores": [
        {
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            "attackComplexity": "LOW",
            "attackVector": "LOCAL",
            "availabilityImpact": "HIGH",
            "baseScore": 5.5,
            "baseSeverity": "MEDIUM",
            "confidentialityImpact": "NONE",
            "environmentalsScore": 0.0,
            "integrityImpact": "NONE",
            "privilegesRequired": "LOW",
            "scope": "UNCHANGED",
            "temporalScore": 5.5,
            "userInteraction": "NONE",
            "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H",
            "version": "3.1"
          },
          "products": [
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            "12138-5",
            "12138-4",
            "12138-3",
            "12138-2",
            "12138-1"
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        }
      ],
      "title": "An issue was discovered in the Linux kernel 3.2 through 5.10.16 as used by Xen. Grant mapping operations often occur in batch hypercalls where a number of operations are done in a single hypercall the success or failure of each one is reported to the backend driver and the backend driver then loops over the results performing follow-up actions based on the success or failure of each operation. Unfortunately when running in PV mode the Linux backend drivers mishandle this: Some errors are ignored effectively implying their success from the success of related batch elements. In other cases errors resulting from one batch element lead to further batch elements not being inspected and hence successful ones to not be possible to properly unmap upon error recovery. Only systems with Linux backends running in PV mode are vulnerable. Linux backends run in HVM / PVH modes are not vulnerable. This affects arch/*/xen/p2m.c and drivers/xen/gntdev.c."
    }
  ]
}


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