fkie_cve-2025-39713
Vulnerability from fkie_nvd
Published
2025-09-05 18:15
Modified
2025-09-08 16:25
Severity ?
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.
References
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/1c2769dc80255824542ea5a4ff1a07dcdeb1603f
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/2964dbe631fd21ad7873b1752b895548d3c12496
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/3c3e33b7edca7a2d6a96801f287f9faeb684d655
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/6aaef1a75985865d8c6c5b65fb54152060faba48
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/7af160aea26c7dc9e6734d19306128cce156ec40
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/ed905fe7cba03cf22ae0b84cf1b73cd1c070423a
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/fbc81e78d75bf28972bc22b1599559557b1a1b83
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/ff9dd3db6cd4c6b54a2ecbc58151bea4ec63bc59
Impacted products
Vendor Product Version


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{
  "cveTags": [],
  "descriptions": [
    {
      "lang": "en",
      "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nmedia: rainshadow-cec: fix TOCTOU race condition in rain_interrupt()\n\nIn the interrupt handler rain_interrupt(), the buffer full check on\nrain-\u003ebuf_len is performed before acquiring rain-\u003ebuf_lock. This\ncreates a Time-of-Check to Time-of-Use (TOCTOU) race condition, as\nrain-\u003ebuf_len is concurrently accessed and modified in the work\nhandler rain_irq_work_handler() under the same lock.\n\nMultiple interrupt invocations can race, with each reading buf_len\nbefore it becomes full and then proceeding. This can lead to both\ninterrupts attempting to write to the buffer, incrementing buf_len\nbeyond its capacity (DATA_SIZE) and causing a buffer overflow.\n\nFix this bug by moving the spin_lock() to before the buffer full\ncheck. This ensures that the check and the subsequent buffer modification\nare performed atomically, preventing the race condition. An corresponding\nspin_unlock() is added to the overflow path to correctly release the\nlock.\n\nThis possible bug was found by an experimental static analysis tool\ndeveloped by our team."
    }
  ],
  "id": "CVE-2025-39713",
  "lastModified": "2025-09-08T16:25:38.810",
  "metrics": {},
  "published": "2025-09-05T18:15:48.720",
  "references": [
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/1c2769dc80255824542ea5a4ff1a07dcdeb1603f"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/2964dbe631fd21ad7873b1752b895548d3c12496"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/3c3e33b7edca7a2d6a96801f287f9faeb684d655"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/6aaef1a75985865d8c6c5b65fb54152060faba48"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/7af160aea26c7dc9e6734d19306128cce156ec40"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/ed905fe7cba03cf22ae0b84cf1b73cd1c070423a"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/fbc81e78d75bf28972bc22b1599559557b1a1b83"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/ff9dd3db6cd4c6b54a2ecbc58151bea4ec63bc59"
    }
  ],
  "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
  "vulnStatus": "Awaiting Analysis"
}


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