CVE-2023-53685 : Détail

CVE-2023-53685

5.5
/
Moyen
0.01%V4
Local
2025-10-07
16h15 +00:00
2026-02-26
23h10 +00:00
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Descriptions du CVE

In the Linux kernel, the following vulnerability has been resolved: tun: Fix memory leak for detached NAPI queue. syzkaller reported [0] memory leaks of sk and skb related to the TUN device with no repro, but we can reproduce it easily with: struct ifreq ifr = {} int fd_tun, fd_tmp; char buf[4] = {}; fd_tun = openat(AT_FDCWD, "/dev/net/tun", O_WRONLY, 0); ifr.ifr_flags = IFF_TUN | IFF_NAPI | IFF_MULTI_QUEUE; ioctl(fd_tun, TUNSETIFF, &ifr); ifr.ifr_flags = IFF_DETACH_QUEUE; ioctl(fd_tun, TUNSETQUEUE, &ifr); fd_tmp = socket(AF_PACKET, SOCK_PACKET, 0); ifr.ifr_flags = IFF_UP; ioctl(fd_tmp, SIOCSIFFLAGS, &ifr); write(fd_tun, buf, sizeof(buf)); close(fd_tun); If we enable NAPI and multi-queue on a TUN device, we can put skb into tfile->sk.sk_write_queue after the queue is detached. We should prevent it by checking tfile->detached before queuing skb. Note this must be done under tfile->sk.sk_write_queue.lock because write() and ioctl(IFF_DETACH_QUEUE) can run concurrently. Otherwise, there would be a small race window: write() ioctl(IFF_DETACH_QUEUE) `- tun_get_user `- __tun_detach |- if (tfile->detached) |- tun_disable_queue | `-> false | `- tfile->detached = tun | `- tun_queue_purge |- spin_lock_bh(&queue->lock) `- __skb_queue_tail(queue, skb) Another solution is to call tun_queue_purge() when closing and reattaching the detached queue, but it could paper over another problems. Also, we do the same kind of test for IFF_NAPI_FRAGS. [0]: unreferenced object 0xffff88801edbc800 (size 2048): comm "syz-executor.1", pid 33269, jiffies 4295743834 (age 18.756s) hex dump (first 32 bytes): 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................ 00 00 07 40 00 00 00 00 00 00 00 00 00 00 00 00 ...@............ backtrace: [<000000008c16ea3d>] __do_kmalloc_node mm/slab_common.c:965 [inline] [<000000008c16ea3d>] __kmalloc+0x4a/0x130 mm/slab_common.c:979 [<000000003addde56>] kmalloc include/linux/slab.h:563 [inline] [<000000003addde56>] sk_prot_alloc+0xef/0x1b0 net/core/sock.c:2035 [<000000003e20621f>] sk_alloc+0x36/0x2f0 net/core/sock.c:2088 [<0000000028e43843>] tun_chr_open+0x3d/0x190 drivers/net/tun.c:3438 [<000000001b0f1f28>] misc_open+0x1a6/0x1f0 drivers/char/misc.c:165 [<000000004376f706>] chrdev_open+0x111/0x300 fs/char_dev.c:414 [<00000000614d379f>] do_dentry_open+0x2f9/0x750 fs/open.c:920 [<000000008eb24774>] do_open fs/namei.c:3636 [inline] [<000000008eb24774>] path_openat+0x143f/0x1a30 fs/namei.c:3791 [<00000000955077b5>] do_filp_open+0xce/0x1c0 fs/namei.c:3818 [<00000000b78973b0>] do_sys_openat2+0xf0/0x260 fs/open.c:1356 [<00000000057be699>] do_sys_open fs/open.c:1372 [inline] [<00000000057be699>] __do_sys_openat fs/open.c:1388 [inline] [<00000000057be699>] __se_sys_openat fs/open.c:1383 [inline] [<00000000057be699>] __x64_sys_openat+0x83/0xf0 fs/open.c:1383 [<00000000a7d2182d>] do_syscall_x64 arch/x86/entry/common.c:50 [inline] [<00000000a7d2182d>] do_syscall_64+0x3c/0x90 arch/x86/entry/common.c:80 [<000000004cc4e8c4>] entry_SYSCALL_64_after_hwframe+0x72/0xdc unreferenced object 0xffff88802f671700 (size 240): comm "syz-executor.1", pid 33269, jiffies 4295743854 (age 18.736s) hex dump (first 32 bytes): 68 c9 db 1e 80 88 ff ff 68 c9 db 1e 80 88 ff ff h.......h....... 00 c0 7b 2f 80 88 ff ff 00 c8 db 1e 80 88 ff ff ..{/............ backtrace: [<00000000e9d9fdb6>] __alloc_skb+0x223/0x250 net/core/skbuff.c:644 [<000000002c3e4e0b>] alloc_skb include/linux/skbuff.h:1288 [inline] [<000000002c3e4e0b>] alloc_skb_with_frags+0x6f/0x350 net/core/skbuff.c:6378 [<00000000825f98d7>] sock_alloc_send_pskb+0x3ac/0x3e0 net/core/sock.c:2729 [<00000000e9eb3df3>] tun_alloc_skb drivers/net/tun.c:1529 [inline] [< ---truncated---

Informations du CVE

Faiblesses connexes

CWE-ID Nom de la faiblesse Source
CWE-401 Missing Release of Memory after Effective Lifetime
The product does not sufficiently track and release allocated memory after it has been used, making the memory unavailable for reallocation and reuse.

Métriques

Métriques Score Gravité CVSS Vecteur Source
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 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.

Products Mentioned

Configuraton 0

Linux>>Linux_kernel >> Version From (including) 3.8 To (excluding) 6.1.30

Linux>>Linux_kernel >> Version From (including) 6.2 To (excluding) 6.3.4

Linux>>Linux_kernel >> Version 6.4

Linux>>Linux_kernel >> Version 6.4

Références