Attacker Value
Unknown
(0 users assessed)
Exploitability
Unknown
(0 users assessed)
User Interaction
None
Privileges Required
Low
Attack Vector
Local
0

CVE-2024-56670

Disclosure Date: December 27, 2024 •
CVE-2024-56670 CVSS v3 Base Score: 5.5
Add MITRE ATT&CK tactics and techniques that apply to this CVE.

Description

In the Linux kernel, the following vulnerability has been resolved:

usb: gadget: u_serial: Fix the issue that gs_start_io crashed due to accessing null pointer

Considering that in some extreme cases,
when u_serial driver is accessed by multiple threads,
Thread A is executing the open operation and calling the gs_open,
Thread B is executing the disconnect operation and calling the
gserial_disconnect function,The port->port_usb pointer will be set to NULL.

E.g.

Thread A                                 Thread B
gs_open()                                gadget_unbind_driver()
gs_start_io()                            composite_disconnect()
gs_start_rx()                            gserial_disconnect()
...                                      ...
spin_unlock(&port->port_lock)
status = usb_ep_queue()                  spin_lock(&port->port_lock)
spin_lock(&port->port_lock)              port->port_usb = NULL
gs_free_requests(port->port_usb->in)     spin_unlock(&port->port_lock)
Crash

This causes thread A to access a null pointer (port->port_usb is null)
when calling the gs_free_requests function, causing a crash.

If port_usb is NULL, the release request will be skipped as it
will be done by gserial_disconnect.

So add a null pointer check to gs_start_io before attempting
to access the value of the pointer port->port_usb.

Call trace:
gs_start_io+0x164/0x25c
gs_open+0x108/0x13c
tty_open+0x314/0x638
chrdev_open+0x1b8/0x258
do_dentry_open+0x2c4/0x700
vfs_open+0x2c/0x3c
path_openat+0xa64/0xc60
do_filp_open+0xb8/0x164
do_sys_openat2+0x84/0xf0
__arm64_sys_openat+0x70/0x9c
invoke_syscall+0x58/0x114
el0_svc_common+0x80/0xe0
do_el0_svc+0x1c/0x28
el0_svc+0x38/0x68

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CVSS V3 Severity and Metrics
Base Score:
5.5 Medium
Impact Score:
3.6
Exploitability Score:
1.8
Vector:
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
Attack Vector (AV):
Local
Attack Complexity (AC):
Low
Privileges Required (PR):
Low
User Interaction (UI):
None
Scope (S):
Unchanged
Confidentiality (C):
None
Integrity (I):
None
Availability (A):
High

General Information

Offensive Application
Unknown
Utility Class
Unknown
Ports
Unknown
OS
Unknown
Vulnerable Versions
Linux 4efdfdc32d8d6307f968cd99f1db64468471bab1
Linux not down converted
Prerequisites
Unknown
Discovered By
Unknown
PoC Author
Unknown
Metasploit Module
Unknown
Reporter
Unknown
Technical Analysis