fkie_cve-2019-18423
Vulnerability from fkie_nvd
Published
2019-10-31 14:15
Modified
2024-11-21 04:33
Severity ?
Summary
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
Impacted products
| Vendor | Product | Version | |
|---|---|---|---|
| xen | xen | * | |
| debian | debian_linux | 9.0 | |
| debian | debian_linux | 10.0 | |
| fedoraproject | fedora | 29 | |
| fedoraproject | fedora | 30 | |
| fedoraproject | fedora | 31 |
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"lang": "en",
"value": "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-\u003emax_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-\u003emax_mapped_gfn will be updated using the original frame. It would be possible to set p2m-\u003emax_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-\u003emax_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."
},
{
"lang": "es",
"value": "Se detect\u00f3 un problema en Xen versiones hasta 4.12.x, permitiendo a usuarios del sistema operativo invitado de ARM causar una denegaci\u00f3n de servicio por medio de una hipercall Xmapme_add_to_physmap. p2m-)max_mapped_gfn es utilizado por las funciones p2m_resolve_translation_fault() y p2m_get_entry() para comprobar trama f\u00edsica del invitado. El resto del c\u00f3digo en las dos funciones asumir\u00e1 que existe una tabla root v\u00e1lida y lo comprobar\u00e1 con BUG_ON(). La funci\u00f3n p2m_get_root_pointer() ignorar\u00e1 los bits superiores no utilizados de una trama f\u00edsica de invitado. Esto significa que la funci\u00f3n p2m_set_entry() renombrar\u00e1 la trama. Sin embargo, p2m-)max_mapped_gfn ser\u00e1 actualizada utilizando la trama original. Ser\u00eda posible establecer p2m-)max_mapped_gfn lo suficientemente alto como para cubrir una trama que conllevar\u00eda a p2m_get_root_pointer() a devolver NULL en p2m_get_entry() y p2m_resolve_translation_fault(). Adicionalmente, la comprobaci\u00f3n de saneamiento en p2m-)max_mapped_gfn est\u00e1 por un paso permitiendo que el \"highest mapped + 1\" sea considerado v\u00e1lido. Sin embargo, p2m_get_root_pointer() devolver\u00e1 NULL. El problema podr\u00eda desencadenarse con una hipercall especialmente dise\u00f1ada XENMEM_add_to_physmap{, _batch} seguido de un acceso a una direcci\u00f3n (por medio de hipercall o acceso directo) que pasa la comprobaci\u00f3n de saneamiento pero hace que la funci\u00f3n p2m_get_root_pointer() devuelva NULL. Un administrador invitado malicioso puede causar un bloqueo del hipervisor, resultando en una Denegaci\u00f3n de Servicio (DoS). Xen versi\u00f3n 4.8 y mas recientes son vulnerables. Solo los sistemas Arm son vulnerables. Los sistemas x86 no est\u00e1n afectados."
}
],
"id": "CVE-2019-18423",
"lastModified": "2024-11-21T04:33:14.140",
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"published": "2019-10-31T14:15:11.137",
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}
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Sightings
| Author | Source | Type | Date |
|---|
Nomenclature
- Seen: The vulnerability was mentioned, discussed, or seen somewhere by the user.
- Confirmed: The vulnerability is confirmed from an analyst perspective.
- Exploited: This vulnerability was exploited and seen by the user reporting the sighting.
- Patched: This vulnerability was successfully patched by the user reporting the sighting.
- Not exploited: This vulnerability was not exploited or seen by the user reporting the sighting.
- Not confirmed: The user expresses doubt about the veracity of the vulnerability.
- Not patched: This vulnerability was not successfully patched by the user reporting the sighting.
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