CVE-2021-47277— Linux kernel 安全漏洞
一分钟漏洞结论
影响对象
Linux Linux
利用判断
尚无明确在野利用证据，仍需结合暴露面评估
建议动作
优先检查厂商安全公告和参考链接中的修复版本；无法立即升级时，限制受影响服务暴露并加强监测。
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，该漏洞源于访客可以以 gfn 无效的方式访问无效的物理地址。
可能的 ATT&CK 技术 1 AI
T1570 · Lateral Tool Transfer影响版本矩阵 18
| 厂商 | 产品 | 版本范围 | 状态 |
|---|---|---|---|
| Linux | Linux | 8a7ae055f3533b520401c170ac55e30628b34df5< 3098b86390a6b9ea52657689f08410baf130ceff |
affected |
8a7ae055f3533b520401c170ac55e30628b34df5< 740621309b25bbf619b8a0ba5fd50a8e58989441 |
affected | ||
8a7ae055f3533b520401c170ac55e30628b34df5< 361ce3b917aff93123e9e966d8608655c967f438 |
affected | ||
8a7ae055f3533b520401c170ac55e30628b34df5< 22b87fb17a28d37331bb9c1110737627b17f6781 |
affected | ||
8a7ae055f3533b520401c170ac55e30628b34df5< bff1fbf0cf0712686f1df59a83fba6e31d2746a0 |
affected | ||
8a7ae055f3533b520401c170ac55e30628b34df5< 7af299b97734c7e7f465b42a2139ce4d77246975 |
affected | ||
8a7ae055f3533b520401c170ac55e30628b34df5< ed0e2a893092c7fcb4ff7ba74e5efce53a6f5940 |
affected | ||
8a7ae055f3533b520401c170ac55e30628b34df5< da27a83fd6cc7780fea190e1f5c19e87019da65c |
affected | ||
| … +10 条更多 | |||
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一、 漏洞 CVE-2021-47277 基础信息
漏洞信息
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Vulnerability Title
kvm: avoid speculation-based attacks from out-of-range memslot accesses
来源: CVE Program / CVE List V5
Vulnerability Description
In the Linux kernel, the following vulnerability has been resolved:
kvm: avoid speculation-based attacks from out-of-range memslot accesses
KVM's mechanism for accessing guest memory translates a guest physical
address (gpa) to a host virtual address using the right-shifted gpa
(also known as gfn) and a struct kvm_memory_slot. The translation is
performed in __gfn_to_hva_memslot using the following formula:
hva = slot->userspace_addr + (gfn - slot->base_gfn) * PAGE_SIZE
It is expected that gfn falls within the boundaries of the guest's
physical memory. However, a guest can access invalid physical addresses
in such a way that the gfn is invalid.
__gfn_to_hva_memslot is called from kvm_vcpu_gfn_to_hva_prot, which first
retrieves a memslot through __gfn_to_memslot. While __gfn_to_memslot
does check that the gfn falls within the boundaries of the guest's
physical memory or not, a CPU can speculate the result of the check and
continue execution speculatively using an illegal gfn. The speculation
can result in calculating an out-of-bounds hva. If the resulting host
virtual address is used to load another guest physical address, this
is effectively a Spectre gadget consisting of two consecutive reads,
the second of which is data dependent on the first.
Right now it's not clear if there are any cases in which this is
exploitable. One interesting case was reported by the original author
of this patch, and involves visiting guest page tables on x86. Right
now these are not vulnerable because the hva read goes through get_user(),
which contains an LFENCE speculation barrier. However, there are
patches in progress for x86 uaccess.h to mask kernel addresses instead of
using LFENCE; once these land, a guest could use speculation to read
from the VMM's ring 3 address space. Other architectures such as ARM
already use the address masking method, and would be susceptible to
this same kind of data-dependent access gadgets. Therefore, this patch
proactively protects from these attacks by masking out-of-bounds gfns
in __gfn_to_hva_memslot, which blocks speculation of invalid hvas.
Sean Christopherson noted that this patch does not cover
kvm_read_guest_offset_cached. This however is limited to a few bytes
past the end of the cache, and therefore it is unlikely to be useful in
the context of building a chain of data dependent accesses.
来源: CVE Program / CVE List V5
CVSS Information
N/A
来源: CVE Program / CVE List V5
Vulnerability Type
N/A
来源: CVE Program / CVE List V5
Vulnerability Title
Linux kernel 安全漏洞
来源: 中国国家信息安全漏洞库 CNNVD
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，该漏洞源于访客可以以 gfn 无效的方式访问无效的物理地址。
来源: 中国国家信息安全漏洞库 CNNVD
CVSS Information
N/A
来源: 中国国家信息安全漏洞库 CNNVD
Vulnerability Type
N/A
来源: 中国国家信息安全漏洞库 CNNVD
受影响产品
二、漏洞 CVE-2021-47277 的公开POC
| # | POC 描述 | 源链接 | 神龙链接 |
|---|
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CVE-2021-47277 其他参考 (8)
同批安全公告 · Linux · 2024-05-21 · 共 361 条
| CVE-2023-52741 | 9.8 CRITICAL | Linux kernel 安全漏洞 |
| CVE-2021-47378 | 9.8 CRITICAL | Linux kernel 安全漏洞 |
| CVE-2023-52755 | 9.8 CRITICAL | Linux kernel 安全漏洞 |
| CVE-2021-47427 | 9.8 CRITICAL | Linux kernel 安全漏洞 |
| CVE-2023-52732 | 9.8 CRITICAL | Linux kernel 安全漏洞 |
| CVE-2021-47328 | 9.8 CRITICAL | Linux kernel 安全漏洞 |
| CVE-2021-47232 | 9.8 CRITICAL | Linux kernel 安全漏洞 |
| CVE-2023-52846 | 8.8 HIGH | Linux kernel 安全漏洞 |
| CVE-2023-52769 | 8.8 HIGH | Linux kernel 安全漏洞 |
| CVE-2023-52790 | 8.8 HIGH | Linux kernel 安全漏洞 |
| CVE-2021-47308 | 8.8 HIGH | Linux kernel 安全漏洞 |
| CVE-2021-47390 | 8.8 HIGH | Linux kernel 安全漏洞 |
| CVE-2023-52801 | 8.8 HIGH | Linux kernel 安全漏洞 |
| CVE-2023-52776 | 8.8 HIGH | Linux kernel 安全漏洞 |
| CVE-2023-52798 | 8.8 HIGH | Linux kernel 安全漏洞 |
| CVE-2021-47388 | 8.8 HIGH | Linux kernel 安全漏洞 |
| CVE-2023-52829 | 8.4 HIGH | Linux kernel 安全漏洞 |
| CVE-2021-47240 | 8.4 HIGH | Linux kernel 安全漏洞 |
| CVE-2021-47352 | 8.4 HIGH | Linux kernel 安全漏洞 |
| CVE-2021-47244 | 8.2 HIGH | Linux kernel 安全漏洞 |
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IV. Related Vulnerabilities
V. Comments for CVE-2021-47277
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