| Summary | arm: guest_physmap_remove_page not removing the p2m mappings The functions to remove one or more entries from a guest p2m pagetable on Arm (p2m_remove_mapping, guest_physmap_remove_page, and p2m_set_entry with mfn set to INVALID_MFN) do not actually clear the pagetable entry if the entry doesn't have the valid bit set. It is possible to have a valid pagetable entry without the valid bit set when a guest operating system uses set/way cache maintenance instructions. For instance, a guest issuing a set/way cache maintenance instruction, then calling the XENMEM_decrease_reservation hypercall to give back memory pages to Xen, might be able to retain access to those pages even after Xen started reusing them for other purposes. |
|---|---|
| Publication Date | Jan. 25, 2022, 11:15 p.m. |
| Registration Date | Jan. 26, 2022, 10 a.m. |
| Last Update | Nov. 21, 2024, 3:47 p.m. |
| CVSS3.1 : HIGH | |
| スコア | 7.8 |
|---|---|
| Vector | CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H |
| 攻撃元区分(AV) | ローカル |
| 攻撃条件の複雑さ(AC) | 低 |
| 攻撃に必要な特権レベル(PR) | 低 |
| 利用者の関与(UI) | 不要 |
| 影響の想定範囲(S) | 変更なし |
| 機密性への影響(C) | 高 |
| 完全性への影響(I) | 高 |
| 可用性への影響(A) | 高 |
| CVSS2.0 : MEDIUM | |
| Score | 4.6 |
|---|---|
| Vector | AV:L/AC:L/Au:N/C:P/I:P/A:P |
| 攻撃元区分(AV) | ローカル |
| 攻撃条件の複雑さ(AC) | 低 |
| 攻撃前の認証要否(Au) | 不要 |
| 機密性への影響(C) | 低 |
| 完全性への影響(I) | 低 |
| 可用性への影響(A) | 低 |
| Get all privileges. | いいえ |
| Get user privileges | いいえ |
| Get other privileges | いいえ |
| User operation required | いいえ |
| Configuration1 | or higher | or less | more than | less than | |
| cpe:2.3:o:xen:xen:*:*:*:*:*:*:arm:* | 4.12.0 | ||||
| Configuration2 | or higher | or less | more than | less than | |
| cpe:2.3:o:fedoraproject:fedora:34:*:*:*:*:*:*:* | |||||
| Configuration3 | or higher | or less | more than | less than | |
| cpe:2.3:o:debian:debian_linux:11.0:*:*:*:*:*:*:* | |||||