CVE-2024-55916

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Source
https://cve.org/CVERecord?id=CVE-2024-55916
Import Source
https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2024-55916.json
JSON Data
https://api.osv.dev/v1/vulns/CVE-2024-55916
Downstream
Related
Published
2025-01-11T12:35:44Z
Modified
2026-08-12T03:51:14Z
Severity
  • 5.5 (Medium) CVSS_V3 - CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H CVSS Calculator
Summary
Drivers: hv: util: Avoid accessing a ringbuffer not initialized yet
Details

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 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.

Database specific 
{
    "cna_assigner": "Linux",
    "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2024/55xxx/CVE-2024-55916.json"
}
References

Affected packages

Git / git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git

Affected ranges

Type
GIT
Repo
https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
Events
Introduced
e0fa3e5e7df61eb2c339c9f0067c202c0cdeec2c
Fixed
f091a224a2c82f1e302b1768d73bb6332f687321
Fixed
d81f4e73aff9b861671df60e5100ad25cc16fbf8
Fixed
042253c57be901bfd19f15b68267442b70f510d5
Fixed
718fe694a334be9d1a89eed22602369ac18d6583
Fixed
89fcec5e466b3ac9b376e0d621c71effa1a7983f
Fixed
3dd7a30c6d7f90afcf19e9b072f572ba524d7ec6
Fixed
07a756a49f4b4290b49ea46e089cbe6f79ff8d26

Database specific

source 
"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2024-55916.json"

Linux / Kernel

Package

Name
Kernel

Affected ranges

Type
ECOSYSTEM
Events
Introduced
4.9.0
Fixed
5.4.289
Type
ECOSYSTEM
Events
Introduced
5.5.0
Fixed
5.10.233
Type
ECOSYSTEM
Events
Introduced
5.11.0
Fixed
5.15.176
Type
ECOSYSTEM
Events
Introduced
5.16.0
Fixed
6.1.122
Type
ECOSYSTEM
Events
Introduced
6.2.0
Fixed
6.6.68
Type
ECOSYSTEM
Events
Introduced
6.7.0
Fixed
6.12.7

Database specific

source 
"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2024-55916.json"