An issue was discovered in Xen through 4.12.x allowing ARM guest OS users to cause a denial of service via a XENMEM_add_to_physmap hypercall. p2m->max_mapped_gfn is used by the functions p2m_resolve_translation_fault() and p2m_get_entry() to sanity check guest physical frame. The rest of the code in the two functions will assume that there is a valid root table and check that with BUG_ON(). The function p2m_get_root_pointer() will ignore the unused top bits of a guest physical frame. This means that the function p2m_set_entry() will alias the frame. However, p2m->max_mapped_gfn will be updated using the original frame. It would be possible to set p2m->max_mapped_gfn high enough to cover a frame that would lead p2m_get_root_pointer() to return NULL in p2m_get_entry() and p2m_resolve_translation_fault(). Additionally, the sanity check on p2m->max_mapped_gfn is off-by-one allowing "highest mapped + 1" to be considered valid. However, p2m_get_root_pointer() will return NULL. The problem could be triggered with a specially crafted hypercall XENMEM_add_to_physmap{, _batch} followed by an access to an address (via hypercall or direct access) that passes the sanity check but cause p2m_get_root_pointer() to return NULL. A malicious guest administrator may cause a hypervisor crash, resulting in a Denial of Service (DoS). Xen version 4.8 and newer are vulnerable. Only Arm systems are vulnerable. x86 systems are not affected.
References
Link | Resource |
---|---|
http://www.openwall.com/lists/oss-security/2019/10/31/4 | Mailing List Patch Third Party Advisory |
http://xenbits.xen.org/xsa/advisory-301.html | Patch Vendor Advisory |
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/2BQKX7M2RHCWDBKNPX4KEBI3MJIH6AYZ/ | |
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/I5WWPW4BSZDDW7VHU427XTVXV7ROOFFW/ | |
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/IZYATWNUGHRBG6I3TC24YHP5Y3J7I6KH/ | |
https://seclists.org/bugtraq/2020/Jan/21 | Mailing List Third Party Advisory |
https://security.gentoo.org/glsa/202003-56 | Third Party Advisory |
https://www.debian.org/security/2020/dsa-4602 | Third Party Advisory |
History
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MITRE Information
Status: PUBLISHED
Assigner: mitre
Published: 2019-10-31T13:36:27
Updated: 2020-03-26T14:06:21
Reserved: 2019-10-24T00:00:00
Link: CVE-2019-18423
JSON object: View
NVD Information
Status : Modified
Published: 2019-10-31T14:15:11.137
Modified: 2023-11-07T03:06:26.877
Link: CVE-2019-18423
JSON object: View
Redhat Information
No data.
CWE