CVE-2021-47590

mptcp: fix deadlock in __mptcp_push_pending()

Severity Score

5.5

*CVSS v3.1

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: fix deadlock in __mptcp_push_pending()

__mptcp_push_pending() may call mptcp_flush_join_list() with subflow
socket lock held. If such call hits mptcp_sockopt_sync_all() then
subsequently __mptcp_sockopt_sync() could try to lock the subflow
socket for itself, causing a deadlock.

sysrq: Show Blocked State
task:ss-server state:D stack: 0 pid: 938 ppid: 1 flags:0x00000000
Call Trace:
<TASK>
__schedule+0x2d6/0x10c0
? __mod_memcg_state+0x4d/0x70
? csum_partial+0xd/0x20
? _raw_spin_lock_irqsave+0x26/0x50
schedule+0x4e/0xc0
__lock_sock+0x69/0x90
? do_wait_intr_irq+0xa0/0xa0
__lock_sock_fast+0x35/0x50
mptcp_sockopt_sync_all+0x38/0xc0
__mptcp_push_pending+0x105/0x200
mptcp_sendmsg+0x466/0x490
sock_sendmsg+0x57/0x60
__sys_sendto+0xf0/0x160
? do_wait_intr_irq+0xa0/0xa0
? fpregs_restore_userregs+0x12/0xd0
__x64_sys_sendto+0x20/0x30
do_syscall_64+0x38/0x90
entry_SYSCALL_64_after_hwframe+0x44/0xae
RIP: 0033:0x7f9ba546c2d0
RSP: 002b:00007ffdc3b762d8 EFLAGS: 00000246 ORIG_RAX: 000000000000002c
RAX: ffffffffffffffda RBX: 00007f9ba56c8060 RCX: 00007f9ba546c2d0
RDX: 000000000000077a RSI: 0000000000e5e180 RDI: 0000000000000234
RBP: 0000000000cc57f0 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00007f9ba56c8060
R13: 0000000000b6ba60 R14: 0000000000cc7840 R15: 41d8685b1d7901b8
</TASK>

Fix the issue by using __mptcp_flush_join_list() instead of plain
mptcp_flush_join_list() inside __mptcp_push_pending(), as suggested by
Florian. The sockopt sync will be deferred to the workqueue.

En el kernel de Linux, se resolvió la siguiente vulnerabilidad: mptcp: corrige el punto muerto en __mptcp_push_pending() __mptcp_push_pending() puede llamar a mptcp_flush_join_list() con el bloqueo del socket de subflujo retenido. Si dicha llamada llega a mptcp_sockopt_sync_all(), posteriormente __mptcp_sockopt_sync() podría intentar bloquear el socket de subflujo por sí mismo, provocando un punto muerto. sysrq: Mostrar estado bloqueado tarea: estado del servidor ss: D pila: 0 pid: 938 ppid: 1 banderas: 0x00000000 Seguimiento de llamadas: __schedule+0x2d6/0x10c0? __mod_memcg_state+0x4d/0x70 ? csum_partial+0xd/0x20? _raw_spin_lock_irqsave+0x26/0x50 horario+0x4e/0xc0 __lock_sock+0x69/0x90 ? do_wait_intr_irq+0xa0/0xa0 __lock_sock_fast+0x35/0x50 mptcp_sockopt_sync_all+0x38/0xc0 __mptcp_push_pending+0x105/0x200 mptcp_sendmsg+0x466/0x490 sock_sendmsg+0x57/0x60 __sys_sendto+0xf0/0x160? do_wait_intr_irq+0xa0/0xa0? fpregs_restore_userregs+0x12/0xd0 __x64_sys_sendto+0x20/0x30 do_syscall_64+0x38/0x90 Entry_SYSCALL_64_after_hwframe+0x44/0xae RIP: 0033:0x7f9ba546c2d0 RSP: dc3b762d8 EFLAGS: 00000246 ORIG_RAX: 000000000000002c RAX: ffffffffffffffda RBX: 00007f9ba56c8060 RCX: 00007f9ba546c2d0 RDX: 000000000000077a RSI: 0000000000e5e180 RDI: 0000000000000234 RBP: 0000000000cc57f0 R08: 0000000000000000 R09: 00000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 00007f9ba56c8060 R13: 0000000000b6ba60 R14: 0000000000cc7840 R15: 41d8685b1d7901b8 Solucione el problema usando __mptcp_flush_join_list() en su lugar de mptcp_flush_join_list() simple dentro __mptcp_push_pending(), como sugiere Florian. La sincronización de sockopt se aplazará a la cola de trabajo.

*Credits: N/A

CVSS Scores

Red Hatv3.1 5.5

Attack Vector

Local

Attack Complexity

Low

Privileges Required

Low

User Interaction

None

Scope

Unchanged

Confidentiality

None

Integrity

None

Availability

High

* 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
2024-06-20 EPSS Updated
2024-12-19 CVE Updated
---------- Exploited in Wild
---------- KEV Due Date
---------- First Exploit

CWE

CWE-833: Deadlock

CAPEC

References (5)

URL	Tag	Source
https://git.kernel.org/stable/c/1b3e7ede1365a24db1b4fd837e58a595f52fa4ad	Vuln. Introduced

URL	Date	SRC

URL	Date	SRC
https://git.kernel.org/stable/c/23311b92755ffa9087332d1bb8c71c0f6a10cc08	2021-12-22
https://git.kernel.org/stable/c/3d79e3756ca90f7a6087b77b62c1d9c0801e0820	2021-12-15

URL	Date	SRC
https://access.redhat.com/security/cve/CVE-2021-47590	2022-05-10
https://bugzilla.redhat.com/show_bug.cgi?id=2293237	2022-05-10

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"				>= 5.13 < 5.15.11 Search vendor "Linux" for product "Linux Kernel" and version " >= 5.13 < 5.15.11"		en		Affected
Linux Search vendor "Linux"		Linux Kernel Search vendor "Linux" for product "Linux Kernel"				>= 5.13 < 5.16 Search vendor "Linux" for product "Linux Kernel" and version " >= 5.13 < 5.16"		en		Affected