CVE-2025-39713

Summary

In the Linux kernel, the following vulnerability has been resolved: media: rainshadow-cec: fix TOCTOU race condition in rain_interrupt() In the interrupt handler rain_interrupt(), the buffer full check on rain->buf_len is performed before acquiring rain->buf_lock. This creates a Time-of-Check to Time-of-Use (TOCTOU) race condition, as rain->buf_len is concurrently accessed and modified in the work handler rain_irq_work_handler() under the same lock. Multiple interrupt invocations can race, with each reading buf_len before it becomes full and then proceeding. This can lead to both interrupts attempting to write to the buffer, incrementing buf_len beyond its capacity (DATA_SIZE) and causing a buffer overflow. Fix this bug by moving the spin_lock() to before the buffer full check. This ensures that the check and the subsequent buffer modification are performed atomically, preventing the race condition. An corresponding spin_unlock() is added to the overflow path to correctly release the lock. This possible bug was found by an experimental static analysis tool developed by our team.

Impact & exploitability

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

Affected products we track (2)

Recommendation

Apply the vendor fix in your normal patch cycle. Open any affected product above for its exact safe version.

Official patch: https://git.kernel.org/stable/c/1c2769dc80255824542ea5a4ff1a07dcdeb1603f ↗

Additional information

• NVD record
• https://git.kernel.org/stable/c/1c2769dc80255824542ea5a4ff1a07dcdeb1603fPatch
• https://git.kernel.org/stable/c/2964dbe631fd21ad7873b1752b895548d3c12496Patch
• https://git.kernel.org/stable/c/3c3e33b7edca7a2d6a96801f287f9faeb684d655Patch
• https://git.kernel.org/stable/c/6aaef1a75985865d8c6c5b65fb54152060faba48Patch
• https://git.kernel.org/stable/c/7af160aea26c7dc9e6734d19306128cce156ec40Patch
• https://git.kernel.org/stable/c/ed905fe7cba03cf22ae0b84cf1b73cd1c070423aPatch
• https://git.kernel.org/stable/c/fbc81e78d75bf28972bc22b1599559557b1a1b83Patch
• https://git.kernel.org/stable/c/ff9dd3db6cd4c6b54a2ecbc58151bea4ec63bc59Patch