Описание
In the Linux kernel, the following vulnerability has been resolved: ext4: fix uninitialized ratelimit_state->lock access in __ext4_fill_super() In the following concurrency we will access the uninitialized rs->lock: ext4_fill_super ext4_register_sysfs // sysfs registered msg_ratelimit_interval_ms // Other processes modify rs->interval to // non-zero via msg_ratelimit_interval_ms ext4_orphan_cleanup ext4_msg(sb, KERN_INFO, "Errors on filesystem, " __ext4_msg ___ratelimit(&(EXT4_SB(sb)->s_msg_ratelimit_state) if (!rs->interval) // do nothing if interval is 0 return 1; raw_spin_trylock_irqsave(&rs->lock, flags) raw_spin_trylock(lock) _raw_spin_trylock __raw_spin_trylock spin_acquire(&lock->dep_map, 0, 1, RET_IP) lock_acquire __lock_acquire register_lock_class assign_lock_key dump_stack(); ratelimit_state_init(&sbi->s_msg_ratelimit_state, 5 * HZ, 10); raw_spin_lock_init(&rs->lock); // init rs->lock here and get the following dump_stack:
INFO: trying to register non-static key. The code is fine but needs lockdep annotation, or maybe you didn't initialize this object before use? turning off the locking correctness validator. CPU: 12 PID: 753 Comm: mount Tainted: G E 6.7.0-rc6-next-20231222 #504 [...] Call Trace: dump_stack_lvl+0xc5/0x170 dump_stack+0x18/0x30 register_lock_class+0x740/0x7c0 __lock_acquire+0x69/0x13a0 lock_acquire+0x120/0x450 _raw_spin_trylock+0x98/0xd0 ___ratelimit+0xf6/0x220 __ext4_msg+0x7f/0x160 [ext4] ext4_orphan_cleanup+0x665/0x740 [ext4] __ext4_fill_super+0x21ea/0x2b10 [ext4] ext4_fill_super+0x14d/0x360 [ext4] [...]
Normally interval is 0 until s_msg_ratelimit_state is initialized, so
___ratelimit() does nothing. But registering sysfs precedes initializing
rs->lock, so it is possible to change rs->interval to a non-zero value
via the msg_ratelimit_interval_ms interface of sysfs while rs->lock is
uninitialized, and then a call to ext4_msg triggers the problem by
accessing an uninitialized rs->lock. Therefore register sysfs after all
initializations are complete to avoid such problems.
A vulnerability was found in the Linux kernel's ext4 filesystem within the __ext4_fill_super() function, where uninitialized access to ratelimit_state->lock can occur, where the sysfs interface is registered before properly initializing rs->lock, potentially allowing other processes to modify rs->interval to a non-zero value.
Отчет
A moderate severity flaw was found in the Linux kernel's ext4 filesystem, affecting the kernel and kernel-rt packages in Red Hat Enterprise Linux 8 and Red Hat Enterprise Linux 9 as well as the kernels used by Red Hat managed OpenShift offerings. When an ext4 filesystem is mounted, __ext4_fill_super() registers the ext4 sysfs interface, which exposes the msg_ratelimit_interval_ms parameter, before the filesystem's message ratelimit state (s_msg_ratelimit_state) and its spinlock are initialized. A privileged local user can exploit this race by setting the message rate limit interval to a non-zero value through sysfs while the lock is still uninitialized; a subsequent call to ext4_msg(), such as those issued during orphan cleanup, then accesses the uninitialized ratelimit_state->lock. As demonstrated upstream, this triggers a lockdep warning that turns off the locking correctness validator, and operating on an uninitialized spinlock can affect kernel stability and system availability. The flaw has no confidentiality or integrity impact. The Red Hat severity of Moderate (CVSS 5.5, AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H) is consistent with the upstream NIST rating, and Fedora is recorded as not affected. The fix is delegated to the Red Hat Enterprise Linux kernel team, and affected streams are addressed through the standard update process.
Меры по смягчению последствий
Mitigation for this issue is either not available or the currently available options do not meet the Red Hat Product Security criteria comprising ease of use and deployment, applicability to widespread installation base or stability.
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-2024:7001 | 24.09.2024 |
| Red Hat Enterprise Linux 8 | kernel | Fixed | RHSA-2024:7000 | 24.09.2024 |
| Red Hat Enterprise Linux 8.6 Advanced Mission Critical Update Support | kernel | Fixed | RHSA-2024:8616 | 30.10.2024 |
| Red Hat Enterprise Linux 8.6 Telecommunications Update Service | kernel | Fixed | RHSA-2024:8616 | 30.10.2024 |
| Red Hat Enterprise Linux 8.6 Update Services for SAP Solutions | kernel | Fixed | RHSA-2024:8616 | 30.10.2024 |
| Red Hat Enterprise Linux 8.8 Extended Update Support | kernel | Fixed | RHSA-2024:8107 | 15.10.2024 |
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Дополнительная информация
Статус:
EPSS
5.5 Medium
CVSS3
Связанные уязвимости
In the Linux kernel, the following vulnerability has been resolved: ext4: fix uninitialized ratelimit_state->lock access in __ext4_fill_super() In the following concurrency we will access the uninitialized rs->lock: ext4_fill_super ext4_register_sysfs // sysfs registered msg_ratelimit_interval_ms // Other processes modify rs->interval to // non-zero via msg_ratelimit_interval_ms ext4_orphan_cleanup ext4_msg(sb, KERN_INFO, "Errors on filesystem, " __ext4_msg ___ratelimit(&(EXT4_SB(sb)->s_msg_ratelimit_state) if (!rs->interval) // do nothing if interval is 0 return 1; raw_spin_trylock_irqsave(&rs->lock, flags) raw_spin_trylock(lock) _raw_spin_trylock __raw_spin_trylock spin_acquire(&lock->dep_map, 0, 1, _RET_IP_) lock_acquire __lock_acquire register_lock_class assign_lock_key dump_stack(); ratelimit_state_init(&sbi->s_msg_ratelimit_state, 5 * HZ, 10); raw_spin_lock_init(&rs->lock); // init rs->lock here and get the following dump_stack: ===============================================...
In the Linux kernel, the following vulnerability has been resolved: ext4: fix uninitialized ratelimit_state->lock access in __ext4_fill_super() In the following concurrency we will access the uninitialized rs->lock: ext4_fill_super ext4_register_sysfs // sysfs registered msg_ratelimit_interval_ms // Other processes modify rs->interval to // non-zero via msg_ratelimit_interval_ms ext4_orphan_cleanup ext4_msg(sb, KERN_INFO, "Errors on filesystem, " __ext4_msg ___ratelimit(&(EXT4_SB(sb)->s_msg_ratelimit_state) if (!rs->interval) // do nothing if interval is 0 return 1; raw_spin_trylock_irqsave(&rs->lock, flags) raw_spin_trylock(lock) _raw_spin_trylock __raw_spin_trylock spin_acquire(&lock->dep_map, 0, 1, _RET_IP_) lock_acquire __lock_acquire regist
ext4: fix uninitialized ratelimit_state->lock access in __ext4_fill_super()
In the Linux kernel, the following vulnerability has been resolved: e ...
In the Linux kernel, the following vulnerability has been resolved: ext4: fix uninitialized ratelimit_state->lock access in __ext4_fill_super() In the following concurrency we will access the uninitialized rs->lock: ext4_fill_super ext4_register_sysfs // sysfs registered msg_ratelimit_interval_ms // Other processes modify rs->interval to // non-zero via msg_ratelimit_interval_ms ext4_orphan_cleanup ext4_msg(sb, KERN_INFO, "Errors on filesystem, " __ext4_msg ___ratelimit(&(EXT4_SB(sb)->s_msg_ratelimit_state) if (!rs->interval) // do nothing if interval is 0 return 1; raw_spin_trylock_irqsave(&rs->lock, flags) raw_spin_trylock(lock) _raw_spin_trylock __raw_spin_trylock spin_acquire(&lock->dep_map, 0, 1, _RET_IP_) lock_acquire __lock_acquire reg...
EPSS
5.5 Medium
CVSS3