Описание
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:
__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
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
A use-after-free flaw was found in net/bridge/br_mst.c in the Linux kernel. This issue may lead to compromised Confidentiality and Integrity, and can crash.
Отчет
Red Hat has determined this vulnerability to be moderate impact, as it is triggered within the bridge vlan processing context, a network-layer operation that mainly affects how vlan states are updated and does not directly/implicitly expose sensitive user-space memory, limiting the confidentiality impact. This processing context does not provide direct control over arbitrary memory writes, limiting the impact to integrity. The most likely result is a kernel panic or crash. Within regulated environments, a combination of the following controls acts as a significant barrier to successfully exploiting a CWE-416: Use After Free vulnerability and therefore downgrades the severity of this particular CVE from Moderate to Low. Access to the platform is granted only after successful hard token-based multi-factor authentication (MFA) and is governed by least privilege to ensure that only authorized users and roles can execute or modify code. Red Hat also enforces least functionality, enabling only essential features, services, and ports. Hardening guidelines ensure the most restrictive settings required for operations, while baseline configurations enforce safe memory allocation and deallocation practices to reduce the risk of use-after-free vulnerabilities. The environment employs IPS/IDS and antimalware solutions to detect and prevent malicious code and provide real-time visibility into memory usage, lowering the risk of arbitrary code execution. Static code analysis and peer reviews enforce strong input validation and error handling, reducing the likelihood of denial-of-service (DoS) attacks. In the event of successful exploitation, process isolation prevents a compromised process from accessing memory freed by another, containing potential impact. Finally, memory protection mechanisms such as Data Execution Prevention (DEP) and Address Space Layout Randomization (ASLR) enhance resilience against memory-related vulnerabilities.
Затронутые пакеты
| Платформа | Пакет | Состояние | Рекомендация | Релиз |
|---|---|---|---|---|
| Red Hat Enterprise Linux 6 | kernel | Out of support scope | ||
| Red Hat Enterprise Linux 7 | kernel | Out of support scope | ||
| Red Hat Enterprise Linux 7 | kernel-rt | Out of support scope | ||
| Red Hat Enterprise Linux 9 | kernel-rt | Affected | ||
| Red Hat Enterprise Linux 8 | kernel-rt | Fixed | RHSA-2024:5102 | 08.08.2024 |
| Red Hat Enterprise Linux 8 | kernel | Fixed | RHSA-2024:5101 | 08.08.2024 |
| Red Hat Enterprise Linux 8.8 Extended Update Support | kernel | Fixed | RHSA-2024:6206 | 03.09.2024 |
| Red Hat Enterprise Linux 9 | kernel | Fixed | RHSA-2024:6567 | 11.09.2024 |
| Red Hat Enterprise Linux 9 | kernel | Fixed | RHSA-2024:6567 | 11.09.2024 |
| Red Hat Enterprise Linux 9.2 Extended Update Support | kernel | Fixed | RHSA-2024:7489 | 02.10.2024 |
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Дополнительная информация
Статус:
EPSS
6.6 Medium
CVSS3
Связанные уязвимости
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_privat...
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 n
In the Linux kernel, the following vulnerability has been resolved: n ...
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_grou...
Уязвимость функции br_mst_set_state() реализации протокола IEEE 802.1D ядра операционной системы Linux, позволяющая нарушителю оказать воздействие на конфиденциальность, целостность и доступность защищаемой информации
EPSS
6.6 Medium
CVSS3