CVE-2021-47274 : Détail

CVE-2021-47274

9.8
/
Critique
Overflow
0.46%V4
Network
2024-05-21
14h20 +00:00
2024-12-19
07h38 +00:00
CVE.org
NVD
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Descriptions du CVE

tracing: Correct the length check which causes memory corruption

In the Linux kernel, the following vulnerability has been resolved: tracing: Correct the length check which causes memory corruption We've suffered from severe kernel crashes due to memory corruption on our production environment, like, Call Trace: [1640542.554277] general protection fault: 0000 [#1] SMP PTI [1640542.554856] CPU: 17 PID: 26996 Comm: python Kdump: loaded Tainted:G [1640542.556629] RIP: 0010:kmem_cache_alloc+0x90/0x190 [1640542.559074] RSP: 0018:ffffb16faa597df8 EFLAGS: 00010286 [1640542.559587] RAX: 0000000000000000 RBX: 0000000000400200 RCX: 0000000006e931bf [1640542.560323] RDX: 0000000006e931be RSI: 0000000000400200 RDI: ffff9a45ff004300 [1640542.560996] RBP: 0000000000400200 R08: 0000000000023420 R09: 0000000000000000 [1640542.561670] R10: 0000000000000000 R11: 0000000000000000 R12: ffffffff9a20608d [1640542.562366] R13: ffff9a45ff004300 R14: ffff9a45ff004300 R15: 696c662f65636976 [1640542.563128] FS: 00007f45d7c6f740(0000) GS:ffff9a45ff840000(0000) knlGS:0000000000000000 [1640542.563937] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [1640542.564557] CR2: 00007f45d71311a0 CR3: 000000189d63e004 CR4: 00000000003606e0 [1640542.565279] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 [1640542.566069] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 [1640542.566742] Call Trace: [1640542.567009] anon_vma_clone+0x5d/0x170 [1640542.567417] __split_vma+0x91/0x1a0 [1640542.567777] do_munmap+0x2c6/0x320 [1640542.568128] vm_munmap+0x54/0x70 [1640542.569990] __x64_sys_munmap+0x22/0x30 [1640542.572005] do_syscall_64+0x5b/0x1b0 [1640542.573724] entry_SYSCALL_64_after_hwframe+0x44/0xa9 [1640542.575642] RIP: 0033:0x7f45d6e61e27 James Wang has reproduced it stably on the latest 4.19 LTS. After some debugging, we finally proved that it's due to ftrace buffer out-of-bound access using a debug tool as follows: [ 86.775200] BUG: Out-of-bounds write at addr 0xffff88aefe8b7000 [ 86.780806] no_context+0xdf/0x3c0 [ 86.784327] __do_page_fault+0x252/0x470 [ 86.788367] do_page_fault+0x32/0x140 [ 86.792145] page_fault+0x1e/0x30 [ 86.795576] strncpy_from_unsafe+0x66/0xb0 [ 86.799789] fetch_memory_string+0x25/0x40 [ 86.804002] fetch_deref_string+0x51/0x60 [ 86.808134] kprobe_trace_func+0x32d/0x3a0 [ 86.812347] kprobe_dispatcher+0x45/0x50 [ 86.816385] kprobe_ftrace_handler+0x90/0xf0 [ 86.820779] ftrace_ops_assist_func+0xa1/0x140 [ 86.825340] 0xffffffffc00750bf [ 86.828603] do_sys_open+0x5/0x1f0 [ 86.832124] do_syscall_64+0x5b/0x1b0 [ 86.835900] entry_SYSCALL_64_after_hwframe+0x44/0xa9 commit b220c049d519 ("tracing: Check length before giving out the filter buffer") adds length check to protect trace data overflow introduced in 0fc1b09ff1ff, seems that this fix can't prevent overflow entirely, the length check should also take the sizeof entry->array[0] into account, since this array[0] is filled the length of trace data and occupy addtional space and risk overflow.

Informations du CVE

Faiblesses connexes

CWE-ID Nom de la faiblesse Source
CWE-125 Out-of-bounds Read
The product reads data past the end, or before the beginning, of the intended buffer.

Métriques

Métriques Score Gravité CVSS Vecteur Source
V3.1 9.8 CRITICAL CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/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.

Network

The vulnerable component is bound to the network stack and the set of possible attackers extends beyond the other options listed below, up to and including the entire Internet. Such a vulnerability is often termed “remotely exploitable” and can be thought of as an attack being exploitable at the protocol level one or more network hops away (e.g., across one or more routers).

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.

None

The attacker is unauthorized prior to attack, and therefore does not require any access to settings or files of the vulnerable system to carry out an attack.

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.

High

There is a total loss of confidentiality, resulting in all resources within the impacted component being divulged to the attacker. Alternatively, access to only some restricted information is obtained, but the disclosed information presents a direct, serious impact. For example, an attacker steals the administrator's password, or private encryption keys of a web server.

Integrity Impact

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

High

There is a total loss of integrity, or a complete loss of protection. For example, the attacker is able to modify any/all files protected by the impacted component. Alternatively, only some files can be modified, but malicious modification would present a direct, serious consequence to 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.

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EPSS

EPSS est un modèle de notation qui prédit la probabilité qu'une vulnérabilité soit exploitée.

Score EPSS

Le modèle EPSS produit un score de probabilité compris entre 0 et 1 (0 et 100 %). Plus la note est élevée, plus la probabilité qu'une vulnérabilité soit exploitée est grande.

Percentile EPSS

Le percentile est utilisé pour classer les CVE en fonction de leur score EPSS. Par exemple, une CVE dans le 95e percentile selon son score EPSS est plus susceptible d'être exploitée que 95 % des autres CVE. Ainsi, le percentile sert à comparer le score EPSS d'une CVE par rapport à d'autres CVE.
EPSS First.org

Products Mentioned

Configuraton 0

Linux>>Linux_kernel >> Version From (including) 4.9.258 To (excluding) 4.9.273

Linux>>Linux_kernel >> Version From (including) 4.14.222 To (excluding) 4.14.237

Linux>>Linux_kernel >> Version From (including) 4.19.177 To (excluding) 4.19.195

Linux>>Linux_kernel >> Version From (including) 5.4.99 To (excluding) 5.4.126

Linux>>Linux_kernel >> Version From (including) 5.10.17 To (excluding) 5.10.44

Linux>>Linux_kernel >> Version From (including) 5.11 To (excluding) 5.12.11

Linux>>Linux_kernel >> Version 5.13

Linux>>Linux_kernel >> Version 5.13

Linux>>Linux_kernel >> Version 5.13

Linux>>Linux_kernel >> Version 5.13

Linux>>Linux_kernel >> Version 5.13

Références