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GHSA-R68C-P976-5JMG

Vulnerability from github – Published: 2024-06-20 12:31 – Updated: 2024-09-18 18:30
VLAI
Details

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

PCI: pciehp: Fix infinite loop in IRQ handler upon power fault

The Power Fault Detected bit in the Slot Status register differs from all other hotplug events in that it is sticky: It can only be cleared after turning off slot power. Per PCIe r5.0, sec. 6.7.1.8:

If a power controller detects a main power fault on the hot-plug slot, it must automatically set its internal main power fault latch [...]. The main power fault latch is cleared when software turns off power to the hot-plug slot.

The stickiness used to cause interrupt storms and infinite loops which were fixed in 2009 by commits 5651c48cfafe ("PCI pciehp: fix power fault interrupt storm problem") and 99f0169c17f3 ("PCI: pciehp: enable software notification on empty slots").

Unfortunately in 2020 the infinite loop issue was inadvertently reintroduced by commit 8edf5332c393 ("PCI: pciehp: Fix MSI interrupt race"): The hardirq handler pciehp_isr() clears the PFD bit until pciehp's power_fault_detected flag is set. That happens in the IRQ thread pciehp_ist(), which never learns of the event because the hardirq handler is stuck in an infinite loop. Fix by setting the power_fault_detected flag already in the hardirq handler.

Severity
5.5 (Medium)
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
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{
  "affected": [],
  "aliases": [
    "CVE-2021-47617"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-835"
    ],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2024-06-20T11:15:54Z",
    "severity": "MODERATE"
  },
  "details": "In the Linux kernel, the following vulnerability has been resolved:\n\nPCI: pciehp: Fix infinite loop in IRQ handler upon power fault\n\nThe Power Fault Detected bit in the Slot Status register differs from\nall other hotplug events in that it is sticky:  It can only be cleared\nafter turning off slot power.  Per PCIe r5.0, sec. 6.7.1.8:\n\n  If a power controller detects a main power fault on the hot-plug slot,\n  it must automatically set its internal main power fault latch [...].\n  The main power fault latch is cleared when software turns off power to\n  the hot-plug slot.\n\nThe stickiness used to cause interrupt storms and infinite loops which\nwere fixed in 2009 by commits 5651c48cfafe (\"PCI pciehp: fix power fault\ninterrupt storm problem\") and 99f0169c17f3 (\"PCI: pciehp: enable\nsoftware notification on empty slots\").\n\nUnfortunately in 2020 the infinite loop issue was inadvertently\nreintroduced by commit 8edf5332c393 (\"PCI: pciehp: Fix MSI interrupt\nrace\"):  The hardirq handler pciehp_isr() clears the PFD bit until\npciehp\u0027s power_fault_detected flag is set.  That happens in the IRQ\nthread pciehp_ist(), which never learns of the event because the hardirq\nhandler is stuck in an infinite loop.  Fix by setting the\npower_fault_detected flag already in the hardirq handler.",
  "id": "GHSA-r68c-p976-5jmg",
  "modified": "2024-09-18T18:30:48Z",
  "published": "2024-06-20T12:31:19Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2021-47617"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/1db58c6584a72102e98af2e600ea184ddaf2b8af"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/23584c1ed3e15a6f4bfab8dc5a88d94ab929ee12"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/3b4c966fb156ff3e70b2526d964952ff7c1574d9"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/464da38ba827f670deac6500a1de9a4f0f44c41d"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/6d6f1f0dac3e3441ecdb1103d4efb11b9ed24dd5"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/ff27f7d0333cff89ec85c419f431aca1b38fb16a"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H",
      "type": "CVSS_V3"
    }
  ]
}



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