CVSS 7.0 · High EPSS 0,16%
Kerentanan Use After Free pada linux kernel. Skor CVSS 3.1 7.0 (High) menurut NVD.
In the Linux kernel, the following vulnerability has been resolved: atm: lec: fix use-after-free in sock_def_readable() A race condition exists between lec_atm_close() setting priv->lecd to NULL and concurrent access to priv->lecd in send_to_lecd(), lec_handle_bridge(), and lec_atm_send(). When the socket is freed via RCU while another thread is still using it, a use-after-free occurs in sock_def_readable() when accessing the socket's wait queue. The root cause is that lec_atm_close() clears priv->lecd without any synchronization, while callers dereference priv->lecd without any protection against concurrent teardown. Fix this by converting priv->lecd to an RCU-protected pointer: - Mark priv->lecd as __rcu in lec.h - Use rcu_assign_pointer() in lec_atm_close() and lecd_attach() for safe pointer assignment - Use rcu_access_pointer() for NULL checks that do not dereference the pointer in lec_start_xmit(), lec_push(), send_to_lecd() and lecd_attach() - Use rcu_read_lock/rcu_dereference/rcu_read_unlock in send_to_lecd(), lec_handle_bridge() and lec_atm_send() to safely access lecd - Use rcu_assign_pointer() followed by synchronize_rcu() in lec_atm_close() to ensure all readers have completed before proceeding. This is safe since lec_atm_close() is called from vcc_release() which holds lock_sock(), a sleeping lock. - Remove the manual sk_receive_queue drain from lec_atm_close() since vcc_destroy_socket() already drains it after lec_atm_close() returns. v2: Switch from spinlock + sock_hold/put approach to RCU to properly fix the race. The v1 spinlock approach had two issues pointed out by Eric Dumazet: 1. priv->lecd was still accessed directly after releasing the lock instead of using a local copy. 2. The spinlock did not prevent packets being queued after lec_atm_close() drains sk_receive_queue since timer and workqueue paths bypass netif_stop_queue(). Note: Syzbot patch testing was attempted but the test VM terminated unexpectedly with "Connection to localhost closed by remote host", likely due to a QEMU AHCI emulation issue unrelated to this fix. Compile testing with "make W=1 net/atm/lec.o" passes cleanly.
CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H
· uraikan di kalkulator | Vendor | Produk | Versi terdampak |
|---|---|---|
| linux | linux kernel | Versi 2.6.12.1 hingga sebelum 5.10.253 |
| linux | linux kernel | Versi 5.11 hingga sebelum 5.15.203 |
| linux | linux kernel | Versi 5.16 hingga sebelum 6.1.168 |
| linux | linux kernel | Versi 6.2 hingga sebelum 6.6.134 |
| linux | linux kernel | Versi 6.7 hingga sebelum 6.12.81 |
| linux | linux kernel | Versi 6.13 hingga sebelum 6.18.22 |
| linux | linux kernel | Versi 6.19 hingga sebelum 6.19.12 |
| 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 |
| linux | linux kernel | Versi 7.0 rc1 |
| linux | linux kernel | Versi 7.0 rc2 |
| linux | linux kernel | Versi 7.0 rc3 |
| linux | linux kernel | Versi 7.0 rc4 |