CVE-2021-46939— 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，该漏洞源于重构trace_clock_global()以永不阻塞。
可能的 ATT&CK 技术 1 AI
T1053 · Scheduled Task/Job影响版本矩阵 20
| 厂商 | 产品 | 版本范围 | 状态 |
|---|---|---|---|
| Linux | Linux | 14131f2f98ac350ee9e73faed916d2238a8b6a0d< 91ca6f6a91f679c8645d7f3307e03ce86ad518c4 |
affected |
14131f2f98ac350ee9e73faed916d2238a8b6a0d< 859b47a43f5a0e5b9a92b621dc6ceaad39fb5c8b |
affected | ||
14131f2f98ac350ee9e73faed916d2238a8b6a0d< 1fca00920327be96f3318224f502e4d5460f9545 |
affected | ||
14131f2f98ac350ee9e73faed916d2238a8b6a0d< d43d56dbf452ccecc1ec735cd4b6840118005d7c |
affected | ||
14131f2f98ac350ee9e73faed916d2238a8b6a0d< c64da3294a7d59a4bf6874c664c13be892f15f44 |
affected | ||
14131f2f98ac350ee9e73faed916d2238a8b6a0d< a33614d52e97fc8077eb0b292189ca7d964cc534 |
affected | ||
14131f2f98ac350ee9e73faed916d2238a8b6a0d< 6e2418576228eeb12e7ba82edb8f9500623942ff |
affected | ||
14131f2f98ac350ee9e73faed916d2238a8b6a0d< 2a1bd74b8186d7938bf004f5603f25b84785f63e |
affected | ||
| … +12 条更多 | |||
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一、 漏洞 CVE-2021-46939 基础信息
漏洞信息
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Vulnerability Title
tracing: Restructure trace_clock_global() to never block
来源: CVE Program / CVE List V5
Vulnerability Description
In the Linux kernel, the following vulnerability has been resolved:
tracing: Restructure trace_clock_global() to never block
It was reported that a fix to the ring buffer recursion detection would
cause a hung machine when performing suspend / resume testing. The
following backtrace was extracted from debugging that case:
Call Trace:
trace_clock_global+0x91/0xa0
__rb_reserve_next+0x237/0x460
ring_buffer_lock_reserve+0x12a/0x3f0
trace_buffer_lock_reserve+0x10/0x50
__trace_graph_return+0x1f/0x80
trace_graph_return+0xb7/0xf0
? trace_clock_global+0x91/0xa0
ftrace_return_to_handler+0x8b/0xf0
? pv_hash+0xa0/0xa0
return_to_handler+0x15/0x30
? ftrace_graph_caller+0xa0/0xa0
? trace_clock_global+0x91/0xa0
? __rb_reserve_next+0x237/0x460
? ring_buffer_lock_reserve+0x12a/0x3f0
? trace_event_buffer_lock_reserve+0x3c/0x120
? trace_event_buffer_reserve+0x6b/0xc0
? trace_event_raw_event_device_pm_callback_start+0x125/0x2d0
? dpm_run_callback+0x3b/0xc0
? pm_ops_is_empty+0x50/0x50
? platform_get_irq_byname_optional+0x90/0x90
? trace_device_pm_callback_start+0x82/0xd0
? dpm_run_callback+0x49/0xc0
With the following RIP:
RIP: 0010:native_queued_spin_lock_slowpath+0x69/0x200
Since the fix to the recursion detection would allow a single recursion to
happen while tracing, this lead to the trace_clock_global() taking a spin
lock and then trying to take it again:
ring_buffer_lock_reserve() {
trace_clock_global() {
arch_spin_lock() {
queued_spin_lock_slowpath() {
/* lock taken */
(something else gets traced by function graph tracer)
ring_buffer_lock_reserve() {
trace_clock_global() {
arch_spin_lock() {
queued_spin_lock_slowpath() {
/* DEAD LOCK! */
Tracing should *never* block, as it can lead to strange lockups like the
above.
Restructure the trace_clock_global() code to instead of simply taking a
lock to update the recorded "prev_time" simply use it, as two events
happening on two different CPUs that calls this at the same time, really
doesn't matter which one goes first. Use a trylock to grab the lock for
updating the prev_time, and if it fails, simply try again the next time.
If it failed to be taken, that means something else is already updating
it.
Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=212761
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，该漏洞源于重构trace_clock_global()以永不阻塞。
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-2021-46939 的公开POC
| # | POC 描述 | 源链接 | 神龙链接 |
|---|
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CVE-2021-46939 补丁与修复 (1)
CVE-2021-46939 其他参考 (7)
同批安全公告 · Linux · 2024-02-27 · 共 67 条
| CVE-2021-46911 | 9.8 CRITICAL | Linux kernel 安全漏洞 |
| CVE-2021-46955 | 8.2 HIGH | Linux kernel 安全漏洞 |
| CVE-2021-46963 | 7.8 HIGH | Linux kernel 安全漏洞 |
| CVE-2021-46925 | 7.8 HIGH | Linux kernel 安全漏洞 |
| CVE-2021-46929 | 7.8 HIGH | Linux kernel 安全漏洞 |
| CVE-2021-46913 | 7.8 HIGH | Linux kernel 安全漏洞 |
| CVE-2021-46973 | 7.8 HIGH | Linux kernel 安全漏洞 |
| CVE-2021-46936 | 7.8 HIGH | Linux kernel 安全漏洞 |
| CVE-2021-46933 | 7.8 HIGH | Linux kernel 安全漏洞 |
| CVE-2021-46969 | 7.8 HIGH | Linux kernel 安全漏洞 |
| CVE-2021-46958 | 7.8 HIGH | Linux kernel 安全漏洞 |
| CVE-2021-46967 | 7.8 HIGH | Linux kernel 安全漏洞 |
| CVE-2021-46921 | 7.8 HIGH | Linux kernel 安全漏洞 |
| CVE-2021-46922 | 7.8 HIGH | Linux kernel 安全漏洞 |
| CVE-2021-46948 | 7.5 HIGH | Linux kernel 安全漏洞 |
| CVE-2021-46960 | 7.5 HIGH | Linux kernel 安全漏洞 |
| CVE-2021-46912 | 7.3 HIGH | Linux kernel 安全漏洞 |
| CVE-2021-46908 | 7.1 HIGH | Linux kernel 安全漏洞 |
| CVE-2021-46974 | 7.1 HIGH | Linux kernel 安全漏洞 |
| CVE-2021-46910 | 7.0 HIGH | Linux kernel 安全漏洞 |
显示前 20 条，共 67 条。 查看全部 → →
IV. Related Vulnerabilities
V. Comments for CVE-2021-46939
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