CVE-2021-47527 Affecting kernel-doc package, versions <0:4.18.0-553.22.1.el8_10


Severity

Recommended
high

Based on AlmaLinux security rating.

Threat Intelligence

EPSS
0.04% (12th percentile)

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  • Snyk IDSNYK-ALMALINUX8-KERNELDOC-8092218
  • published25 Sept 2024
  • disclosed24 Sept 2024

Introduced: 24 Sep 2024

CVE-2021-47527  (opens in a new tab)

How to fix?

Upgrade AlmaLinux:8 kernel-doc to version 0:4.18.0-553.22.1.el8_10 or higher.
This issue was patched in ALSA-2024:7000.

NVD Description

Note: Versions mentioned in the description apply only to the upstream kernel-doc package and not the kernel-doc package as distributed by AlmaLinux. See How to fix? for AlmaLinux:8 relevant fixed versions and status.

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

serial: core: fix transmit-buffer reset and memleak

Commit 761ed4a94582 ("tty: serial_core: convert uart_close to use tty_port_close") converted serial core to use tty_port_close() but failed to notice that the transmit buffer still needs to be freed on final close.

Not freeing the transmit buffer means that the buffer is no longer cleared on next open so that any ioctl() waiting for the buffer to drain might wait indefinitely (e.g. on termios changes) or that stale data can end up being transmitted in case tx is restarted.

Furthermore, the buffer of any port that has been opened would leak on driver unbind.

Note that the port lock is held when clearing the buffer pointer due to the ldisc race worked around by commit a5ba1d95e46e ("uart: fix race between uart_put_char() and uart_shutdown()").

Also note that the tty-port shutdown() callback is not called for console ports so it is not strictly necessary to free the buffer page after releasing the lock (cf. d72402145ace ("tty/serial: do not free trasnmit buffer page under port lock")).

CVSS Scores

version 3.1