CVE-2023-53642 : 詳細

CVE-2023-53642

5.5
/
中
0.02%V4
2025-10-07
16h15 +00:00
Local
2026-02-03
22h29 +00:00
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CVE の説明

In the Linux kernel, the following vulnerability has been resolved: x86: fix clear_user_rep_good() exception handling annotation This code no longer exists in mainline, because it was removed in commit d2c95f9d6802 ("x86: don't use REP_GOOD or ERMS for user memory clearing") upstream. However, rather than backport the full range of x86 memory clearing and copying cleanups, fix the exception table annotation placement for the final 'rep movsb' in clear_user_rep_good(): rather than pointing at the actual instruction that did the user space access, it pointed to the register move just before it. That made sense from a code flow standpoint, but not from an actual usage standpoint: it means that if user access takes an exception, the exception handler won't actually find the instruction in the exception tables. As a result, rather than fixing it up and returning -EFAULT, it would then turn it into a kernel oops report instead, something like: BUG: unable to handle page fault for address: 0000000020081000 #PF: supervisor write access in kernel mode #PF: error_code(0x0002) - not-present page ... RIP: 0010:clear_user_rep_good+0x1c/0x30 arch/x86/lib/clear_page_64.S:147 ... Call Trace: __clear_user arch/x86/include/asm/uaccess_64.h:103 [inline] clear_user arch/x86/include/asm/uaccess_64.h:124 [inline] iov_iter_zero+0x709/0x1290 lib/iov_iter.c:800 iomap_dio_hole_iter fs/iomap/direct-io.c:389 [inline] iomap_dio_iter fs/iomap/direct-io.c:440 [inline] __iomap_dio_rw+0xe3d/0x1cd0 fs/iomap/direct-io.c:601 iomap_dio_rw+0x40/0xa0 fs/iomap/direct-io.c:689 ext4_dio_read_iter fs/ext4/file.c:94 [inline] ext4_file_read_iter+0x4be/0x690 fs/ext4/file.c:145 call_read_iter include/linux/fs.h:2183 [inline] do_iter_readv_writev+0x2e0/0x3b0 fs/read_write.c:733 do_iter_read+0x2f2/0x750 fs/read_write.c:796 vfs_readv+0xe5/0x150 fs/read_write.c:916 do_preadv+0x1b6/0x270 fs/read_write.c:1008 __do_sys_preadv2 fs/read_write.c:1070 [inline] __se_sys_preadv2 fs/read_write.c:1061 [inline] __x64_sys_preadv2+0xef/0x150 fs/read_write.c:1061 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x39/0xb0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x63/0xcd which then looks like a filesystem bug rather than the incorrect exception annotation that it is. [ The alternative to this one-liner fix is to take the upstream series that cleans this all up: 68674f94ffc9 ("x86: don't use REP_GOOD or ERMS for small memory copies") 20f3337d350c ("x86: don't use REP_GOOD or ERMS for small memory clearing") adfcf4231b8c ("x86: don't use REP_GOOD or ERMS for user memory copies") * d2c95f9d6802 ("x86: don't use REP_GOOD or ERMS for user memory clearing") 3639a535587d ("x86: move stac/clac from user copy routines into callers") 577e6a7fd50d ("x86: inline the 'rep movs' in user copies for the FSRM case") 8c9b6a88b7e2 ("x86: improve on the non-rep 'clear_user' function") 427fda2c8a49 ("x86: improve on the non-rep 'copy_user' function") * e046fe5a36a9 ("x86: set FSRS automatically on AMD CPUs that have FSRM") e1f2750edc4a ("x86: remove 'zerorest' argument from __copy_user_nocache()") 034ff37d3407 ("x86: rewrite '__copy_user_nocache' function") with either the whole series or at a minimum the two marked commits being needed to fix this issue ]

CVE の情報

関連する弱点

CWE-ID 弱点名 出典
CWE Other 情報がありません。

メトリクス

メトリクス スコア 深刻度 CVSS ベクター 出典
V3.1 5.5 MEDIUM CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

Base: Exploitabilty Metrics

The Exploitability metrics reflect the characteristics of the thing that is vulnerable, which we refer to formally as the vulnerable component.

Attack Vector

This metric reflects the context by which vulnerability exploitation is possible.

Local

The vulnerable component is not bound to the network stack and the attacker’s path is via read/write/execute capabilities.

Attack Complexity

This metric describes the conditions beyond the attacker’s control that must exist in order to exploit the vulnerability.

Low

Specialized access conditions or extenuating circumstances do not exist. An attacker can expect repeatable success when attacking the vulnerable component.

Privileges Required

This metric describes the level of privileges an attacker must possess before successfully exploiting the vulnerability.

Low

The attacker requires privileges that provide basic user capabilities that could normally affect only settings and files owned by a user. Alternatively, an attacker with Low privileges has the ability to access only non-sensitive resources.

User Interaction

This metric captures the requirement for a human user, other than the attacker, to participate in the successful compromise of the vulnerable component.

None

The vulnerable system can be exploited without interaction from any user.

Base: Scope Metrics

The Scope metric captures whether a vulnerability in one vulnerable component impacts resources in components beyond its security scope.

Scope

Formally, a security authority is a mechanism (e.g., an application, an operating system, firmware, a sandbox environment) that defines and enforces access control in terms of how certain subjects/actors (e.g., human users, processes) can access certain restricted objects/resources (e.g., files, CPU, memory) in a controlled manner. All the subjects and objects under the jurisdiction of a single security authority are considered to be under one security scope. If a vulnerability in a vulnerable component can affect a component which is in a different security scope than the vulnerable component, a Scope change occurs. Intuitively, whenever the impact of a vulnerability breaches a security/trust boundary and impacts components outside the security scope in which vulnerable component resides, a Scope change occurs.

Unchanged

An exploited vulnerability can only affect resources managed by the same security authority. In this case, the vulnerable component and the impacted component are either the same, or both are managed by the same security authority.

Base: Impact Metrics

The Impact metrics capture the effects of a successfully exploited vulnerability on the component that suffers the worst outcome that is most directly and predictably associated with the attack. Analysts should constrain impacts to a reasonable, final outcome which they are confident an attacker is able to achieve.

Confidentiality Impact

This metric measures the impact to the confidentiality of the information resources managed by a software component due to a successfully exploited vulnerability.

None

There is no loss of confidentiality within the impacted component.

Integrity Impact

This metric measures the impact to integrity of a successfully exploited vulnerability. Integrity refers to the trustworthiness and veracity of information.

None

There is no loss of integrity within the impacted component.

Availability Impact

This metric measures the impact to the availability of the impacted component resulting from a successfully exploited vulnerability.

High

There is a total loss of availability, resulting in the attacker being able to fully deny access to resources in the impacted component; this loss is either sustained (while the attacker continues to deliver the attack) or persistent (the condition persists even after the attack has completed). Alternatively, the attacker has the ability to deny some availability, but the loss of availability presents a direct, serious consequence to the impacted component (e.g., the attacker cannot disrupt existing connections, but can prevent new connections; the attacker can repeatedly exploit a vulnerability that, in each instance of a successful attack, leaks a only small amount of memory, but after repeated exploitation causes a service to become completely unavailable).

Temporal Metrics

The Temporal metrics measure the current state of exploit techniques or code availability, the existence of any patches or workarounds, or the confidence in the description of a vulnerability.

Environmental Metrics

These metrics enable the analyst to customize the CVSS score depending on the importance of the affected IT asset to a user’s organization, measured in terms of Confidentiality, Integrity, and Availability.

nvd@nist.gov

EPSS

EPSSは脆弱性が悪用される可能性を予測するスコアリングモデルです。

EPSSスコア

EPSSモデルは0から1(0〜100%)の確率スコアを算出します。スコアが高いほど、脆弱性が悪用される可能性が高いことを示します。

EPSSパーセンタイル

パーセンタイルはCVEをEPSSスコアで順位付けするために使用されます。例えば、EPSSスコアで95パーセンタイルにあるCVEは、他の95%のCVEよりも悪用される可能性が高いことを意味します。パーセンタイルはCVEのEPSSスコアを他のCVEと比較するために使用されます。

関連製品

構成 0

Linux>>Linux_kernel >> Version ~から(含む) 6.1 ~まで(含まない) 6.1.29

Linux>>Linux_kernel >> Version ~から(含む) 6.2 ~まで(含まない) 6.2.16

Linux>>Linux_kernel >> Version ~から(含む) 6.3 ~まで(含まない) 6.3.3

参考資料