Another race in XENMAPSPACE_grant_table handling Guests are permitted access to...
Vulnerability Description
Another race in XENMAPSPACE_grant_table handling Guests are permitted access to certain Xen-owned pages of memory. The majority of such pages remain allocated / associated with a guest for its entire lifetime. Grant table v2 status pages, however, are de-allocated when a guest switches (back) from v2 to v1. Freeing such pages requires that the hypervisor enforce that no parallel request can result in the addition of a mapping of such a page to a guest. That enforcement was missing, allowing guests to retain access to pages that were freed and perhaps re-used for other purposes. Unfortunately, when XSA-379 was being prepared, this similar issue was not noticed.
Impact Analysis
Refer to official advisory for detailed impact metrics.
Remediation
Ensure systems are updated to the latest vendor-supplied patch levels.
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Credits & Attribution
The following person or organization is credited with identifying this vulnerability, as recorded in the NVD database:
- {'credit_data': {'description': {'description_data': [{'lang': 'eng', 'value': 'This issue was discovered by Julien Grall of Amazon.'}]}}}
References
- https://xenbits.xenproject.org/xsa/advisory-384.txt
- http://xenbits.xen.org/xsa/advisory-384.html
- http://www.openwall.com/lists/oss-security/2021/09/08/2
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/L4MI3MQAPGILCLXBGQWPZHGE3ALSO4ZU/
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/CEHZLIR5DFYYQBH55AERWHLO54OFU42C/
- https://www.debian.org/security/2021/dsa-4977
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/3HEHUIUWSSMCQGQY3GWX4J2SZGYP5W2Z/
- https://security.gentoo.org/glsa/202208-23
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Weaknesses (CWE)
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MITRE ATT&CK TTPs
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