GHSA-PF4V-7Q2J-5RW9

Vulnerability from github – Published: 2025-09-05 18:31 – Updated: 2025-11-03 18:31
VLAI?
Details

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.

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{
  "affected": [],
  "aliases": [
    "CVE-2025-39713"
  ],
  "database_specific": {
    "cwe_ids": [],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2025-09-05T18:15:48Z",
    "severity": null
  },
  "details": "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": "GHSA-pf4v-7q2j-5rw9",
  "modified": "2025-11-03T18:31:39Z",
  "published": "2025-09-05T18:31:27Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2025-39713"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/1c2769dc80255824542ea5a4ff1a07dcdeb1603f"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/2964dbe631fd21ad7873b1752b895548d3c12496"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/3c3e33b7edca7a2d6a96801f287f9faeb684d655"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/6aaef1a75985865d8c6c5b65fb54152060faba48"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/7af160aea26c7dc9e6734d19306128cce156ec40"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/ed905fe7cba03cf22ae0b84cf1b73cd1c070423a"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/fbc81e78d75bf28972bc22b1599559557b1a1b83"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/ff9dd3db6cd4c6b54a2ecbc58151bea4ec63bc59"
    },
    {
      "type": "WEB",
      "url": "https://lists.debian.org/debian-lts-announce/2025/10/msg00007.html"
    },
    {
      "type": "WEB",
      "url": "https://lists.debian.org/debian-lts-announce/2025/10/msg00008.html"
    }
  ],
  "schema_version": "1.4.0",
  "severity": []
}


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