CVE-2021-47608— 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，该漏洞源于对check_mem_access()处理的更改存在问题，该问题允许非特权用户泄露内核指针。
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一、 漏洞 CVE-2021-47608 基础信息
漏洞信息
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Vulnerability Title
bpf: Fix kernel address leakage in atomic fetch
来源: CVE Program / CVE List V5
Vulnerability Description
In the Linux kernel, the following vulnerability has been resolved:
bpf: Fix kernel address leakage in atomic fetch
The change in commit 37086bfdc737 ("bpf: Propagate stack bounds to registers
in atomics w/ BPF_FETCH") around check_mem_access() handling is buggy since
this would allow for unprivileged users to leak kernel pointers. For example,
an atomic fetch/and with -1 on a stack destination which holds a spilled
pointer will migrate the spilled register type into a scalar, which can then
be exported out of the program (since scalar != pointer) by dumping it into
a map value.
The original implementation of XADD was preventing this situation by using
a double call to check_mem_access() one with BPF_READ and a subsequent one
with BPF_WRITE, in both cases passing -1 as a placeholder value instead of
register as per XADD semantics since it didn't contain a value fetch. The
BPF_READ also included a check in check_stack_read_fixed_off() which rejects
the program if the stack slot is of __is_pointer_value() if dst_regno < 0.
The latter is to distinguish whether we're dealing with a regular stack spill/
fill or some arithmetical operation which is disallowed on non-scalars, see
also 6e7e63cbb023 ("bpf: Forbid XADD on spilled pointers for unprivileged
users") for more context on check_mem_access() and its handling of placeholder
value -1.
One minimally intrusive option to fix the leak is for the BPF_FETCH case to
initially check the BPF_READ case via check_mem_access() with -1 as register,
followed by the actual load case with non-negative load_reg to propagate
stack bounds to registers.
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，该漏洞源于对check_mem_access()处理的更改存在问题，该问题允许非特权用户泄露内核指针。
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-2021-47608 的公开POC
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CVE-2021-47608 其他参考 (1)
同批安全公告 · Linux · 2024-06-19 · 共 122 条
| CVE-2024-38558 | 10.0 CRITICAL | Linux kernel 安全漏洞 |
| CVE-2024-38570 | 9.8 CRITICAL | Linux kernel 安全漏洞 |
| CVE-2021-47587 | 9.8 CRITICAL | Linux kernel 安全漏洞 |
| CVE-2024-38544 | 9.8 CRITICAL | Linux kernel 安全漏洞 |
| CVE-2021-47611 | 8.1 HIGH | Linux kernel 安全漏洞 |
| CVE-2024-38587 | 7.8 HIGH | Linux kernel 安全漏洞 |
| CVE-2024-38556 | 7.8 HIGH | Linux kernel 安全漏洞 |
| CVE-2024-38610 | 7.8 HIGH | Linux kernel 安全漏洞 |
| CVE-2024-38605 | 7.8 HIGH | Linux kernel 安全漏洞 |
| CVE-2024-38599 | 7.8 HIGH | Linux kernel 安全漏洞 |
| CVE-2024-38592 | 7.8 HIGH | Linux kernel安全漏洞 |
| CVE-2024-38564 | 7.8 HIGH | Linux kernel 安全漏洞 |
| CVE-2024-38568 | 7.8 HIGH | Linux kernel 安全漏洞 |
| CVE-2024-38572 | 7.8 HIGH | Linux kernel安全漏洞 |
| CVE-2024-38578 | 7.8 HIGH | Linux kernel 安全漏洞 |
| CVE-2024-38580 | 7.8 HIGH | Linux kernel 安全漏洞 |
| CVE-2024-38569 | 7.8 HIGH | Linux kernel 安全漏洞 |
| CVE-2024-38583 | 7.8 HIGH | Linux kernel 安全漏洞 |
| CVE-2024-38614 | 7.8 HIGH | Linux kernel安全漏洞 |
| CVE-2024-38588 | 7.8 HIGH | Linux kernel 安全漏洞 |
显示前 20 条，共 122 条。 查看全部 → →
IV. Related Vulnerabilities
V. Comments for CVE-2021-47608
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