CVE-2023-53858

What it actually does

Failure to free a newly allocated clock handle when clk_get_rate() returns an error in s3c24xx_serial_getclk() causes a kernel memory leak.

Why it matters to the business

On systems using the affected Samsung serial driver, repeated error conditions can gradually exhaust kernel memory, leading to reduced stability or denial of service for serial-dependent operations.

How an attack unfolds

An attacker with local access or the ability to induce repeated failures in the clock rate query path (for example via hardware manipulation or driver stress) can trigger the leak path to accumulate unreleased memory over time.

How to fix it

Upgrade the Linux kernel to the version containing commit 755289d67eb9a74ae71bb624902e979c66859444 or any later stable release that includes the fix for the memory leak in s3c24xx_serial_getclk().

How to confirm the fix worked

Inspect the s3c24xx_serial_getclk() function in the kernel source to confirm the clk_put() call now exists on the clk_get_rate() error path; verify the running kernel reports the fixed commit or a superseding version.

Typical attack path

1. Obtain local or hardware-level access to a system running a vulnerable kernel with the samsung_tty driver enabled
2. Induce repeated error returns from clk_get_rate() inside s3c24xx_serial_getclk()
3. Observe gradual kernel memory consumption until system impact occurs

How to detect it

Review kernel logs and memory accounting for repeated allocations originating from the serial clock getter without corresponding frees; correlate with hardware or driver error events.

What your security team should do

• Prioritize kernel updates on all systems exposing the samsung_tty driver
• Review boot and hardware configurations that may repeatedly exercise the clock error path
• Monitor kernel memory statistics for unexplained growth correlated with serial device activity