In the Linux kernel, the following vulnerability has been resolved:
Drivers: hv: util: Avoid accessing a ringbuffer not initialized yet
If the KVP (or VSS) daemon starts before the VMBus channel's ringbuffer is
fully initialized, we can hit the panic below:
hv_utils: Registering HyperV Utility Driver
hv_vmbus: registering driver hv_utils
...
BUG: kernel NULL pointer dereference, address: 0000000000000000
CPU: 44 UID: 0 PID: 2552 Comm: hv_kvp_daemon Tainted: G E 6.11.0-rc3+ #1
RIP: 0010:hv_pkt_iter_first+0x12/0xd0
Call Trace:
...
vmbus_recvpacket
hv_kvp_onchannelcallback
vmbus_on_event
tasklet_action_common
tasklet_action
handle_softirqs
irq_exit_rcu
sysvec_hyperv_stimer0
</IRQ>
<TASK>
asm_sysvec_hyperv_stimer0
...
kvp_register_done
hvt_op_read
vfs_read
ksys_read
__x64_sys_read
This can happen because the KVP/VSS channel callback can be invoked
even before the channel is fully opened:
1) as soon as hv_kvp_init() -> hvutil_transport_init() creates
/dev/vmbus/hv_kvp, the kvp daemon can open the device file immediately and
register itself to the driver by writing a message KVP_OP_REGISTER1 to the
file (which is handled by kvp_on_msg() ->kvp_handle_handshake()) and
reading the file for the driver's response, which is handled by
hvt_op_read(), which calls hvt->on_read(), i.e. kvp_register_done().
2) the problem with kvp_register_done() is that it can cause the
channel callback to be called even before the channel is fully opened,
and when the channel callback is starting to run, util_probe()->
vmbus_open() may have not initialized the ringbuffer yet, so the
callback can hit the panic of NULL pointer dereference.
To reproduce the panic consistently, we can add a "ssleep(10)" for KVP in
__vmbus_open(), just before the first hv_ringbuffer_init(), and then we
unload and reload the driver hv_utils, and run the daemon manually within
the 10 seconds.
Fix the panic by reordering the steps in util_probe() so the char dev
entry used by the KVP or VSS daemon is not created until after
vmbus_open() has completed. This reordering prevents the race condition
from happening.
References
Configurations
Configuration 1 (hide)
|
History
16 Jan 2025, 15:18
| Type | Values Removed | Values Added |
|---|---|---|
| References | () https://git.kernel.org/stable/c/89fcec5e466b3ac9b376e0d621c71effa1a7983f - Patch | |
| References | () https://git.kernel.org/stable/c/718fe694a334be9d1a89eed22602369ac18d6583 - Patch | |
| References | () https://git.kernel.org/stable/c/042253c57be901bfd19f15b68267442b70f510d5 - Patch | |
| References | () https://git.kernel.org/stable/c/3dd7a30c6d7f90afcf19e9b072f572ba524d7ec6 - Patch | |
| References | () https://git.kernel.org/stable/c/d81f4e73aff9b861671df60e5100ad25cc16fbf8 - Patch | |
| References | () https://git.kernel.org/stable/c/07a756a49f4b4290b49ea46e089cbe6f79ff8d26 - Patch | |
| References | () https://git.kernel.org/stable/c/f091a224a2c82f1e302b1768d73bb6332f687321 - Patch | |
| First Time |
Linux linux Kernel
Linux |
|
| CWE | CWE-476 | |
| CPE | cpe:2.3:o:linux:linux_kernel:6.13:rc3:*:*:*:*:*:* cpe:2.3:o:linux:linux_kernel:6.13:rc1:*:*:*:*:*:* cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* cpe:2.3:o:linux:linux_kernel:6.13:rc2:*:*:*:*:*:* |
|
| CVSS |
v2 : v3 : |
v2 : unknown
v3 : 5.5 |
11 Jan 2025, 13:15
| Type | Values Removed | Values Added |
|---|---|---|
| New CVE |
Information
Published : 2025-01-11 13:15
Updated : 2025-01-16 15:18
NVD link : CVE-2024-55916
Mitre link : CVE-2024-55916
JSON object : View
Products Affected
linux
- linux_kernel
CWE
CWE-476
NULL Pointer Dereference