CVE-2024-36979

net: bridge: mst: fix vlan use-after-free

Severity Score

6.6

*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:

net: bridge: mst: fix vlan use-after-free

syzbot reported a suspicious rcu usage[1] in bridge's mst code. While
fixing it I noticed that nothing prevents a vlan to be freed while
walking the list from the same path (br forward delay timer). Fix the rcu
usage and also make sure we are not accessing freed memory by making
br_mst_vlan_set_state use rcu read lock.

[1]
WARNING: suspicious RCU usage
6.9.0-rc6-syzkaller #0 Not tainted
-----------------------------
net/bridge/br_private.h:1599 suspicious rcu_dereference_protected() usage!
...
stack backtrace:
CPU: 1 PID: 8017 Comm: syz-executor.1 Not tainted 6.9.0-rc6-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/27/2024
Call Trace:
<IRQ>
__dump_stack lib/dump_stack.c:88 [inline]
dump_stack_lvl+0x241/0x360 lib/dump_stack.c:114
lockdep_rcu_suspicious+0x221/0x340 kernel/locking/lockdep.c:6712
nbp_vlan_group net/bridge/br_private.h:1599 [inline]
br_mst_set_state+0x1ea/0x650 net/bridge/br_mst.c:105
br_set_state+0x28a/0x7b0 net/bridge/br_stp.c:47
br_forward_delay_timer_expired+0x176/0x440 net/bridge/br_stp_timer.c:88
call_timer_fn+0x18e/0x650 kernel/time/timer.c:1793
expire_timers kernel/time/timer.c:1844 [inline]
__run_timers kernel/time/timer.c:2418 [inline]
__run_timer_base+0x66a/0x8e0 kernel/time/timer.c:2429
run_timer_base kernel/time/timer.c:2438 [inline]
run_timer_softirq+0xb7/0x170 kernel/time/timer.c:2448
__do_softirq+0x2c6/0x980 kernel/softirq.c:554
invoke_softirq kernel/softirq.c:428 [inline]
__irq_exit_rcu+0xf2/0x1c0 kernel/softirq.c:633
irq_exit_rcu+0x9/0x30 kernel/softirq.c:645
instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1043 [inline]
sysvec_apic_timer_interrupt+0xa6/0xc0 arch/x86/kernel/apic/apic.c:1043
</IRQ>
<TASK>
asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:702
RIP: 0010:lock_acquire+0x264/0x550 kernel/locking/lockdep.c:5758
Code: 2b 00 74 08 4c 89 f7 e8 ba d1 84 00 f6 44 24 61 02 0f 85 85 01 00 00 41 f7 c7 00 02 00 00 74 01 fb 48 c7 44 24 40 0e 36 e0 45 <4b> c7 44 25 00 00 00 00 00 43 c7 44 25 09 00 00 00 00 43 c7 44 25
RSP: 0018:ffffc90013657100 EFLAGS: 00000206
RAX: 0000000000000001 RBX: 1ffff920026cae2c RCX: 0000000000000001
RDX: dffffc0000000000 RSI: ffffffff8bcaca00 RDI: ffffffff8c1eaa60
RBP: ffffc90013657260 R08: ffffffff92efe507 R09: 1ffffffff25dfca0
R10: dffffc0000000000 R11: fffffbfff25dfca1 R12: 1ffff920026cae28
R13: dffffc0000000000 R14: ffffc90013657160 R15: 0000000000000246

En el kernel de Linux, se resolvió la siguiente vulnerabilidad: net: bridge: mst: fix vlan use-after-free syzbot informó un uso sospechoso de rcu[1] en el código mst del puente. Mientras lo solucionaba, noté que nada impide que se libere una VLAN mientras se recorre la lista desde el mismo camino (br temporizador de retardo de avance). Corrija el uso de rcu y también asegúrese de que no accedamos a la memoria liberada haciendo que br_mst_vlan_set_state use el bloqueo de lectura de rcu. [1] ADVERTENCIA: uso sospechoso de RCU 6.9.0-rc6-syzkaller #0 No contaminado ----------------------- net/ bridge/br_private.h:1599 ¡uso sospechoso de rcu_dereference_protected()! ... seguimiento de pila: CPU: 1 PID: 8017 Comm: syz-executor.1 No contaminado 6.9.0-rc6-syzkaller #0 Nombre del hardware: Google Google Compute Engine/Google Compute Engine, BIOS Google 27/03/2024 Llamada Seguimiento: __dump_stack lib/dump_stack.c:88 [en línea] dump_stack_lvl+0x241/0x360 lib/dump_stack.c:114 lockdep_rcu_suspicious+0x221/0x340 kernel/locking/lockdep.c:6712 nbp_vlan_group net/bridge/br_private.h :1599 [en línea] br_mst_set_state+0x1ea/0x650 net/bridge/br_mst.c:105 br_set_state+0x28a/0x7b0 net/bridge/br_stp.c:47 br_forward_delay_timer_expired+0x176/0x440 net/bridge/br_stp_timer.c:88 n+0x18e /0x650 kernel/time/timer.c:1793 expire_timers kernel/time/timer.c:1844 [en línea] __run_timers kernel/time/timer.c:2418 [en línea] __run_timer_base+0x66a/0x8e0 kernel/time/timer.c: 2429 run_timer_base kernel/time/timer.c:2438 [en línea] run_timer_softirq+0xb7/0x170 kernel/time/timer.c:2448 __do_softirq+0x2c6/0x980 kernel/softirq.c:554 invoke_softirq kernel/softirq.c:428 [en línea ] __irq_exit_rcu+0xf2/0x1c0 kernel/softirq.c:633 irq_exit_rcu+0x9/0x30 kernel/softirq.c:645 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1043 [en línea] 0xc0 arco/x86 /kernel/apic/apic.c:1043 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:702 RIP: 0010:lock_acquire+0x264/0x550 kernel/locking/lockdep. c:5758 Código: 2b 00 74 08 4c 89 f7 e8 ba d1 84 00 f6 44 24 61 02 0f 85 85 01 00 00 41 f7 c7 00 02 00 00 74 01 fb 48 c7 44 24 40 0e 36 e0 <4b> c7 44 25 00 00 00 00 00 43 c7 44 25 09 00 00 00 00 43 c7 44 25 RSP: 0018:ffffc90013657100 EFLAGS: 00000206 RAX: 0000000000000001 RBX: ffff920026cae2c RCX: 0000000000000001 RDX: dffffc0000000000 RSI: ffffffff8bcaca00 RDI: ffffffff8c1eaa60 RBP: ffffc90013657260 R08: ffffffff92efe507 R09: 1ffffffff25dfca0 R10: dffffc0000000000 R11: ffffbfff25dfca1 R12: 1ffff920026cae28 R13: dffffc0000000000 R14: ffffc90013657160 5: 0000000000000246

*Credits: N/A

CVSS Scores

Red Hatv3.1 6.6

Attack Vector

Local

Attack Complexity

Low

Privileges Required

Low

User Interaction

None

Scope

Unchanged

Confidentiality

Low

Integrity

Low

Availability

High

* Common Vulnerability Scoring System

SSVC

Decision:Track

Exploitation

None

Automatable

Tech. Impact

Partial

* Organization's Worst-case Scenario

Timeline

2024-05-30 CVE Reserved
2024-06-19 CVE Published
2024-08-02 CVE Updated
2024-08-27 EPSS Updated
---------- Exploited in Wild
---------- KEV Due Date
---------- First Exploit

CWE

CWE-416: Use After Free

CAPEC

References (8)

URL	Tag	Source
https://git.kernel.org/stable/c/ec7328b59176227216c461601c6bd0e922232a9b	Vuln. Introduced

URL	Date	SRC

URL	Date	SRC
https://git.kernel.org/stable/c/8ca9a750fc711911ef616ceb627d07357b04545e	2024-06-12
https://git.kernel.org/stable/c/4488617e5e995a09abe4d81add5fb165674edb59	2024-06-12
https://git.kernel.org/stable/c/a2b01e65d9ba8af2bb086d3b7288ca53a07249ac	2024-05-30
https://git.kernel.org/stable/c/e43dd2b1ec746e105b7db5f9ad6ef14685a615a4	2024-05-30
https://git.kernel.org/stable/c/3a7c1661ae1383364cd6092d851f5e5da64d476b	2024-05-15

URL	Date	SRC
https://access.redhat.com/security/cve/CVE-2024-36979	2024-09-11
https://bugzilla.redhat.com/show_bug.cgi?id=2293276	2024-09-11

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"				>= 5.18 < 6.1.93 Search vendor "Linux" for product "Linux Kernel" and version " >= 5.18 < 6.1.93"		en		Affected
Linux Search vendor "Linux"		Linux Kernel Search vendor "Linux" for product "Linux Kernel"				>= 5.18 < 6.6.33 Search vendor "Linux" for product "Linux Kernel" and version " >= 5.18 < 6.6.33"		en		Affected
Linux Search vendor "Linux"		Linux Kernel Search vendor "Linux" for product "Linux Kernel"				>= 5.18 < 6.8.12 Search vendor "Linux" for product "Linux Kernel" and version " >= 5.18 < 6.8.12"		en		Affected
Linux Search vendor "Linux"		Linux Kernel Search vendor "Linux" for product "Linux Kernel"				>= 5.18 < 6.9.3 Search vendor "Linux" for product "Linux Kernel" and version " >= 5.18 < 6.9.3"		en		Affected
Linux Search vendor "Linux"		Linux Kernel Search vendor "Linux" for product "Linux Kernel"				>= 5.18 < 6.10 Search vendor "Linux" for product "Linux Kernel" and version " >= 5.18 < 6.10"		en		Affected