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CVE-2024-26998

serial: core: Clearing the circular buffer before NULLifying it PUBLISHED

Description (CNA)

In the Linux kernel, the following vulnerability has been resolved: serial: core: Clearing the circular buffer before NULLifying it The circular buffer is NULLified in uart_tty_port_shutdown() under the spin lock. However, the PM or other timer based callbacks may still trigger after this event without knowning that buffer pointer is not valid. Since the serial code is a bit inconsistent in checking the buffer state (some rely on the head-tail positions, some on the buffer pointer), it's better to have both aligned, i.e. buffer pointer to be NULL and head-tail possitions to be the same, meaning it's empty. This will prevent asynchronous calls to dereference NULL pointer as reported recently in 8250 case: BUG: kernel NULL pointer dereference, address: 00000cf5 Workqueue: pm pm_runtime_work EIP: serial8250_tx_chars (drivers/tty/serial/8250/8250_port.c:1809) ... ? serial8250_tx_chars (drivers/tty/serial/8250/8250_port.c:1809) __start_tx (drivers/tty/serial/8250/8250_port.c:1551) serial8250_start_tx (drivers/tty/serial/8250/8250_port.c:1654) serial_port_runtime_suspend (include/linux/serial_core.h:667 drivers/tty/serial/serial_port.c:63) __rpm_callback (drivers/base/power/runtime.c:393) ? serial_port_remove (drivers/tty/serial/serial_port.c:50) rpm_suspend (drivers/base/power/runtime.c:447) The proposed change will prevent ->start_tx() to be called during suspend on shut down port.

Affected (CNA)

Vendor / productVersions
Linux / Linuxaffected 434beb66368d4fb4d3119c2116b9398500adbf47 before 7ae7104d54342433a3a73975f6569beefdd86350; affected 43066e32227ecde674e8ae1fcdd4a1ede67680c2 before bb1118905e875c111d7ccef9aee86ac5e4e7f985; affected 43066e32227ecde674e8ae1fcdd4a1ede67680c2 before 9cf7ea2eeb745213dc2a04103e426b960e807940; affected a629a9b2f7699314a4abe8fbc37b0ee667b60f33; affected 6.6.24 before 6.6.29; affected 6.7.12 before 6.8
Linux / Linuxaffected 6.8; unaffected 0 before 6.8; unaffected 6.6.29 through 6.6.*; unaffected 6.8.8 through 6.8.*; unaffected 6.9 through *

CWE

No CWE identifiers supplied.

References

ADP enrichment

CISA-ADP

No English description supplied.

No references supplied.

CVE

No English description supplied.