| ID |
CVE-2023-52982
|
| Sažetak |
In the Linux kernel, the following vulnerability has been resolved:
fscache: Use wait_on_bit() to wait for the freeing of relinquished volume
The freeing of relinquished volume will wake up the pending volume
acquisition by using wake_up_bit(), however it is mismatched with
wait_var_event() used in fscache_wait_on_volume_collision() and it will
never wake up the waiter in the wait-queue because these two functions
operate on different wait-queues.
According to the implementation in fscache_wait_on_volume_collision(),
if the wake-up of pending acquisition is delayed longer than 20 seconds
(e.g., due to the delay of on-demand fd closing), the first
wait_var_event_timeout() will timeout and the following wait_var_event()
will hang forever as shown below:
FS-Cache: Potential volume collision new=00000024 old=00000022
......
INFO: task mount:1148 blocked for more than 122 seconds.
Not tainted 6.1.0-rc6+ #1
task:mount state:D stack:0 pid:1148 ppid:1
Call Trace:
<TASK>
__schedule+0x2f6/0xb80
schedule+0x67/0xe0
fscache_wait_on_volume_collision.cold+0x80/0x82
__fscache_acquire_volume+0x40d/0x4e0
erofs_fscache_register_volume+0x51/0xe0 [erofs]
erofs_fscache_register_fs+0x19c/0x240 [erofs]
erofs_fc_fill_super+0x746/0xaf0 [erofs]
vfs_get_super+0x7d/0x100
get_tree_nodev+0x16/0x20
erofs_fc_get_tree+0x20/0x30 [erofs]
vfs_get_tree+0x24/0xb0
path_mount+0x2fa/0xa90
do_mount+0x7c/0xa0
__x64_sys_mount+0x8b/0xe0
do_syscall_64+0x30/0x60
entry_SYSCALL_64_after_hwframe+0x46/0xb0
Considering that wake_up_bit() is more selective, so fix it by using
wait_on_bit() instead of wait_var_event() to wait for the freeing of
relinquished volume. In addition because waitqueue_active() is used in
wake_up_bit() and clear_bit() doesn't imply any memory barrier, use
clear_and_wake_up_bit() to add the missing memory barrier between
cursor->flags and waitqueue_active(). |
| Reference |
|
| CVSS |
| Base: | 5.5 |
| Impact: | 3.6 |
| Exploitability: | 1.8 |
|
| Pristup |
| Vektor | Složenost | Autentikacija |
| LOCAL |
LOW |
LOW |
|
| Impact |
| Povjerljivost | Cjelovitost | Dostupnost |
| NONE |
NONE |
HIGH |
|
| CVSS vektor |
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H |
| Zadnje važnije ažuriranje |
28-10-2025 - 18:22 |
| Objavljeno |
27-03-2025 - 17:15 |
