ghsa-f834-hvgh-g5v9
Vulnerability from github
Published
2024-04-10 21:30
Modified
2024-11-05 00:31
Severity ?
5.3 (Medium) - CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N
Details

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

scsi: core: sysfs: Fix hang when device state is set via sysfs

This fixes a regression added with:

commit f0f82e2476f6 ("scsi: core: Fix capacity set to zero after offlinining device")

The problem is that after iSCSI recovery, iscsid will call into the kernel to set the dev's state to running, and with that patch we now call scsi_rescan_device() with the state_mutex held. If the SCSI error handler thread is just starting to test the device in scsi_send_eh_cmnd() then it's going to try to grab the state_mutex.

We are then stuck, because when scsi_rescan_device() tries to send its I/O scsi_queue_rq() calls -> scsi_host_queue_ready() -> scsi_host_in_recovery() which will return true (the host state is still in recovery) and I/O will just be requeued. scsi_send_eh_cmnd() will then never be able to grab the state_mutex to finish error handling.

To prevent the deadlock move the rescan-related code to after we drop the state_mutex.

This also adds a check for if we are already in the running state. This prevents extra scans and helps the iscsid case where if the transport class has already onlined the device during its recovery process then we don't need userspace to do it again plus possibly block that daemon.

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{
  "affected": [],
  "aliases": [
    "CVE-2021-47192"
  ],
  "database_specific": {
    "cwe_ids": [],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2024-04-10T19:15:47Z",
    "severity": "MODERATE"
  },
  "details": "In the Linux kernel, the following vulnerability has been resolved:\n\nscsi: core: sysfs: Fix hang when device state is set via sysfs\n\nThis fixes a regression added with:\n\ncommit f0f82e2476f6 (\"scsi: core: Fix capacity set to zero after\nofflinining device\")\n\nThe problem is that after iSCSI recovery, iscsid will call into the kernel\nto set the dev\u0027s state to running, and with that patch we now call\nscsi_rescan_device() with the state_mutex held. If the SCSI error handler\nthread is just starting to test the device in scsi_send_eh_cmnd() then it\u0027s\ngoing to try to grab the state_mutex.\n\nWe are then stuck, because when scsi_rescan_device() tries to send its I/O\nscsi_queue_rq() calls -\u003e scsi_host_queue_ready() -\u003e scsi_host_in_recovery()\nwhich will return true (the host state is still in recovery) and I/O will\njust be requeued. scsi_send_eh_cmnd() will then never be able to grab the\nstate_mutex to finish error handling.\n\nTo prevent the deadlock move the rescan-related code to after we drop the\nstate_mutex.\n\nThis also adds a check for if we are already in the running state. This\nprevents extra scans and helps the iscsid case where if the transport class\nhas already onlined the device during its recovery process then we don\u0027t\nneed userspace to do it again plus possibly block that daemon.",
  "id": "GHSA-f834-hvgh-g5v9",
  "modified": "2024-11-05T00:31:26Z",
  "published": "2024-04-10T21:30:31Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2021-47192"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/4edd8cd4e86dd3047e5294bbefcc0a08f66a430f"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/a792e0128d232251edb5fdf42fb0f9fbb0b44a73"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/bcc0e3175a976b7fa9a353960808adb0bb49ead8"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/edd783162bf2385b43de6764f2d4c6e9f4f6be27"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N",
      "type": "CVSS_V3"
    }
  ]
}


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