CVE-2021-47593

mptcp: clear 'kern' flag from fallback sockets

Severity Score

"-"

*CVSS v-

Exploit Likelihood

*EPSS

Affected Versions

*CPE

Public Exploits

*Multiple Sources

Exploited in Wild

*KEV

Decision

Track

*SSVC

Descriptions

In the Linux kernel, the following vulnerability has been resolved:

mptcp: clear 'kern' flag from fallback sockets

The mptcp ULP extension relies on sk->sk_sock_kern being set correctly:
It prevents setsockopt(fd, IPPROTO_TCP, TCP_ULP, "mptcp", 6); from
working for plain tcp sockets (any userspace-exposed socket).

But in case of fallback, accept() can return a plain tcp sk.
In such case, sk is still tagged as 'kernel' and setsockopt will work.

This will crash the kernel, The subflow extension has a NULL ctx->conn
mptcp socket:

BUG: KASAN: null-ptr-deref in subflow_data_ready+0x181/0x2b0
Call Trace:
tcp_data_ready+0xf8/0x370
[..]

En el kernel de Linux, se ha resuelto la siguiente vulnerabilidad: mptcp: borrar el indicador 'kern' de los sockets de reserva La extensión mptcp ULP depende de que sk->sk_sock_kern esté configurado correctamente: impide que setsockopt(fd, IPPROTO_TCP, TCP_ULP, "mptcp", 6); de funcionar para sockets tcp simples (cualquier socket expuesto al espacio de usuario). Pero en caso de respaldo, aceptar() puede devolver un sk tcp simple. En tal caso, sk todavía está etiquetado como 'kernel' y setsockopt funcionará. Esto bloqueará el kernel. La extensión de subflujo tiene un socket NULL ctx->conn mptcp: ERROR: KASAN: null-ptr-deref en subflow_data_ready+0x181/0x2b0 Seguimiento de llamadas: tcp_data_ready+0xf8/0x370 [..]

*Credits: N/A

CVSS Scores

Attack Vector

Attack Complexity

Privileges Required

User Interaction

Scope

Confidentiality

Integrity

Availability

* Common Vulnerability Scoring System

SSVC

Decision:Track

Exploitation

None

Automatable

Tech. Impact

Partial

* Organization's Worst-case Scenario

Timeline

2024-05-24 CVE Reserved
2024-06-19 CVE Published
2024-11-02 EPSS Updated
2024-12-19 CVE Updated
---------- Exploited in Wild
---------- KEV Due Date
---------- First Exploit

CWE

CAPEC

References (4)

URL	Tag	Source
https://git.kernel.org/stable/c/cf7da0d66cc1a2a19fc5930bb746ffbb2d4cd1be	Vuln. Introduced

URL	Date	SRC

URL	Date	SRC
https://git.kernel.org/stable/c/451f1eded7f56e93aaf52eb547ba97742d9c0e97	2021-12-22
https://git.kernel.org/stable/c/c26ac0ea3a91c210cf90452e625dc441adf3e549	2021-12-22
https://git.kernel.org/stable/c/d6692b3b97bdc165d150f4c1505751a323a80717	2021-12-15

URL	Date	SRC

Affected Vendors, Products, and Versions

Vendor		Product				Version		Other		Status
Vendor	Product	Version	Other	Status	<-- -->	Vendor	Product	Version	Other	Status
Linux Search vendor "Linux"		Linux Kernel Search vendor "Linux" for product "Linux Kernel"				>= 5.6 < 5.10.88 Search vendor "Linux" for product "Linux Kernel" and version " >= 5.6 < 5.10.88"		en		Affected
Linux Search vendor "Linux"		Linux Kernel Search vendor "Linux" for product "Linux Kernel"				>= 5.6 < 5.15.11 Search vendor "Linux" for product "Linux Kernel" and version " >= 5.6 < 5.15.11"		en		Affected
Linux Search vendor "Linux"		Linux Kernel Search vendor "Linux" for product "Linux Kernel"				>= 5.6 < 5.16 Search vendor "Linux" for product "Linux Kernel" and version " >= 5.6 < 5.16"		en		Affected