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CVE-2024-26992— KVM: x86/pmu: Disable support for adaptive PEBS

Quick assessment

Affected
Linux Linux
Exploitation
No confirmed in-the-wild exploitation; assess based on exposure
Recommended action
Check the vendor advisory and references for a fixed version. If immediate upgrade is impossible, restrict exposure and increase monitoring.

Linux kernel是美国Linux基金会的开源操作系统Linux所使用的内核。 Linux kernel存在安全漏洞，该漏洞源于LBR 泄漏。

CVSS 7.3 · High EPSS 0.23% · P13

Affected Version Matrix 10

VendorProduct Version RangeStatus
Linux Linux c59a1f106f5cd4843c097069ff1bb2ad72103a67< 0fb74c00d140a66128afc0003785dcc57e69d312 affected
c59a1f106f5cd4843c097069ff1bb2ad72103a67< 037e48ceccf163899374b601afb6ae8d0bf1d2ac affected
c59a1f106f5cd4843c097069ff1bb2ad72103a67< 7a7650b3ac23e5fc8c990f00e94f787dc84e3175 affected
c59a1f106f5cd4843c097069ff1bb2ad72103a67< 9e985cbf2942a1bb8fcef9adc2a17d90fd7ca8ee affected
6.0 affected
< 6.0 unaffected
6.1.88≤ 6.1.* unaffected
6.6.29≤ 6.6.* unaffected
… +2 more rows
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I. Basic Information for CVE-2024-26992

Vulnerability Information
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Vulnerability Title
KVM: x86/pmu: Disable support for adaptive PEBS
Source: CVE Program / CVE List V5
Vulnerability Description
In the Linux kernel, the following vulnerability has been resolved: KVM: x86/pmu: Disable support for adaptive PEBS Drop support for virtualizing adaptive PEBS, as KVM's implementation is architecturally broken without an obvious/easy path forward, and because exposing adaptive PEBS can leak host LBRs to the guest, i.e. can leak host kernel addresses to the guest. Bug #1 is that KVM doesn't account for the upper 32 bits of IA32_FIXED_CTR_CTRL when (re)programming fixed counters, e.g fixed_ctrl_field() drops the upper bits, reprogram_fixed_counters() stores local variables as u8s and truncates the upper bits too, etc. Bug #2 is that, because KVM _always_ sets precise_ip to a non-zero value for PEBS events, perf will _always_ generate an adaptive record, even if the guest requested a basic record. Note, KVM will also enable adaptive PEBS in individual *counter*, even if adaptive PEBS isn't exposed to the guest, but this is benign as MSR_PEBS_DATA_CFG is guaranteed to be zero, i.e. the guest will only ever see Basic records. Bug #3 is in perf. intel_pmu_disable_fixed() doesn't clear the upper bits either, i.e. leaves ICL_FIXED_0_ADAPTIVE set, and intel_pmu_enable_fixed() effectively doesn't clear ICL_FIXED_0_ADAPTIVE either. I.e. perf _always_ enables ADAPTIVE counters, regardless of what KVM requests. Bug #4 is that adaptive PEBS *might* effectively bypass event filters set by the host, as "Updated Memory Access Info Group" records information that might be disallowed by userspace via KVM_SET_PMU_EVENT_FILTER. Bug #5 is that KVM doesn't ensure LBR MSRs hold guest values (or at least zeros) when entering a vCPU with adaptive PEBS, which allows the guest to read host LBRs, i.e. host RIPs/addresses, by enabling "LBR Entries" records. Disable adaptive PEBS support as an immediate fix due to the severity of the LBR leak in particular, and because fixing all of the bugs will be non-trivial, e.g. not suitable for backporting to stable kernels. Note! This will break live migration, but trying to make KVM play nice with live migration would be quite complicated, wouldn't be guaranteed to work (i.e. KVM might still kill/confuse the guest), and it's not clear that there are any publicly available VMMs that support adaptive PEBS, let alone live migrate VMs that support adaptive PEBS, e.g. QEMU doesn't support PEBS in any capacity.
Source: CVE Program / CVE List V5
CVSS Information
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:L/A:N
Source: CVE Program / CVE List V5
Vulnerability Type
N/A
Source: CVE Program / CVE List V5
Vulnerability Title
Linux kernel 安全漏洞
Source: CNNVD (China National Vulnerability Database)
Vulnerability Description
Linux kernel是美国Linux基金会的开源操作系统Linux所使用的内核。 Linux kernel存在安全漏洞，该漏洞源于LBR 泄漏。
Source: CNNVD (China National Vulnerability Database)
CVSS Information
N/A
Source: CNNVD (China National Vulnerability Database)
Vulnerability Type
N/A
Source: CNNVD (China National Vulnerability Database)

Affected Products

Vendor Product Affected Versions CPE Subscribe
Linux Linux c59a1f106f5cd4843c097069ff1bb2ad72103a67 ~ 0fb74c00d140a66128afc0003785dcc57e69d312 -
Linux Linux 6.0 -

II. Public POCs for CVE-2024-26992

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III. Intelligence Information for CVE-2024-26992

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Mailing List Discussions for CVE-2024-26992 (3)

Other References for CVE-2024-26992 (4)

Same Patch Batch · Linux · 2024-05-01 · 159 CVEs total

CVE-2024-27388 9.8 CRITICAL SUNRPC: fix some memleaks in gssx_dec_option_array
CVE-2024-26953 9.8 CRITICAL net: esp: fix bad handling of pages from page_pool
CVE-2024-26931 8.8 HIGH scsi: qla2xxx: Fix command flush on cable pull
CVE-2024-27053 8.8 HIGH wifi: wilc1000: fix RCU usage in connect path
CVE-2024-26990 8.8 HIGH KVM: x86/mmu: Write-protect L2 SPTEs in TDP MMU when clearing dirty status
CVE-2024-26952 8.3 HIGH ksmbd: fix potencial out-of-bounds when buffer offset is invalid
CVE-2024-27018 8.2 HIGH netfilter: br_netfilter: skip conntrack input hook for promisc packets
CVE-2024-26936 8.2 HIGH ksmbd: validate request buffer size in smb2_allocate_rsp_buf()
CVE-2024-26980 8.2 HIGH ksmbd: fix slab-out-of-bounds in smb2_allocate_rsp_buf
CVE-2024-26954 8.1 HIGH ksmbd: fix slab-out-of-bounds in smb_strndup_from_utf16()
CVE-2024-26994 7.8 HIGH speakup: Avoid crash on very long word
CVE-2024-26966 7.8 HIGH clk: qcom: mmcc-apq8084: fix terminating of frequency table arrays
CVE-2024-26974 7.8 HIGH crypto: qat - resolve race condition during AER recovery
CVE-2024-26976 7.8 HIGH KVM: Always flush async #PF workqueue when vCPU is being destroyed
CVE-2024-27062 7.8 HIGH nouveau: lock the client object tree.
CVE-2024-27061 7.8 HIGH crypto: sun8i-ce - Fix use after free in unprepare
CVE-2024-26983 7.8 HIGH bootconfig: use memblock_free_late to free xbc memory to buddy
CVE-2024-27058 7.8 HIGH tmpfs: fix race on handling dquot rbtree
CVE-2024-27056 7.8 HIGH wifi: iwlwifi: mvm: ensure offloading TID queue exists
CVE-2024-27017 7.8 HIGH netfilter: nft_set_pipapo: walk over current view on netlink dump

Showing top 20 of 159 CVEs. View all on vendor page &rarr; →

IV. Related Vulnerabilities

Same product: Linux
Same vendor: Linux

V. Comments for CVE-2024-26992

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