CVE-2024-38633

2024-06-2111:15:12

Google

osv.dev

linux kernel

vulnerability

max3100

uart driver

removal

code update

CVSS3

5.5

Attack Vector

LOCAL

Attack Complexity

LOW

Privileges Required

LOW

User Interaction

NONE

Scope

UNCHANGED

Confidentiality Impact

NONE

Integrity Impact

NONE

Availability Impact

HIGH

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

AI Score

7.1

Confidence

High

EPSS

Percentile

5.1%

JSON

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

serial: max3100: Update uart_driver_registered on driver removal

The removal of the last MAX3100 device triggers the removal of
the driver. However, code doesn’t update the respective global
variable and after insmod — rmmod — insmod cycle the kernel
oopses:

max3100 spi-PRP0001:01: max3100_probe: adding port 0
BUG: kernel NULL pointer dereference, address: 0000000000000408
…
RIP: 0010:serial_core_register_port+0xa0/0x840
…
max3100_probe+0x1b6/0x280 [max3100]
spi_probe+0x8d/0xb0

Update the actual state so next time UART driver will be registered
again.

Hugo also noticed, that the error path in the probe also affected
by having the variable set, and not cleared. Instead of clearing it
move the assignment after the successfull uart_register_driver() call.