CVSS 7.5 · High EPSS 0,47%
Kerentanan Improper Locking pada linux kernel. Skor CVSS 3.1 7.5 (High) menurut CNA.
In the Linux kernel, the following vulnerability has been resolved: fs/fcntl: fix SOFTIRQ-unsafe lock order in fasync signaling A SOFTIRQ-safe to SOFTIRQ-unsafe lock order deadlock can occur in send_sigio() and send_sigurg() when a process group receives a signal. When FASYNC is configured for a process group (PIDTYPE_PGID), both functions use read_lock(&tasklist_lock) to traverse the task list. However, they are frequently called from softirq context: - send_sigio() via input_inject_event -> kill_fasync - send_sigurg() via tcp_check_urg -> sk_send_sigurg (NET_RX_SOFTIRQ) The deadlock is caused by the rwlock writer fairness mechanism: 1. CPU 0 (process context) holds read_lock(&tasklist_lock) in do_wait(). 2. CPU 1 (process context) attempts write_lock(&tasklist_lock) in fork() or exit() and spins, which blocks all new readers. 3. CPU 0 is interrupted by a softirq (e.g., TCP URG packet reception). 4. The softirq calls send_sigurg() and attempts to acquire read_lock(&tasklist_lock), deadlocking because CPU 1 is waiting. Since PID hashing and do_each_pid_task() traversals are already RCU-protected, the read_lock on tasklist_lock is no longer strictly required for safe traversal. Fix this by replacing tasklist_lock with rcu_read_lock(), aligning the process group signaling path with the single-PID path. This also mitigates a potential remote denial of service vector via TCP URG packets. Lockdep splat: ===================================================== WARNING: SOFTIRQ-safe -> SOFTIRQ-unsafe lock order detected [...] Chain exists of: &dev->event_lock --> &f_owner->lock --> tasklist_lock Possible interrupt unsafe locking scenario: CPU0 CPU1 ---- ---- lock(tasklist_lock); local_irq_disable(); lock(&dev->event_lock); lock(&f_owner->lock); <Interrupt> lock(&dev->event_lock); *** DEADLOCK ***
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
· uraikan di kalkulator | Vendor | Produk | Versi terdampak |
|---|---|---|
| linux | linux kernel | Versi 2.6.12.1 hingga sebelum 5.10.259 |
| linux | linux kernel | Versi 5.11 hingga sebelum 5.15.210 |
| linux | linux kernel | Versi 5.16 hingga sebelum 6.1.176 |
| linux | linux kernel | Versi 6.2 hingga sebelum 6.6.143 |
| linux | linux kernel | Versi 6.7 hingga sebelum 6.12.94 |
| linux | linux kernel | Versi 6.13 hingga sebelum 6.18.36 |
| linux | linux kernel | Versi 6.19 hingga sebelum 7.0.13 |
| linux | linux kernel | Versi 7.1 hingga sebelum 7.1.1 |
| linux | linux kernel | Versi 2.6.12 |
| linux | linux kernel | Versi 2.6.12 rc2 |
| linux | linux kernel | Versi 2.6.12 rc3 |
| linux | linux kernel | Versi 2.6.12 rc4 |
| linux | linux kernel | Versi 2.6.12 rc5 |