ghsa-hh6q-pgh2-779f
Vulnerability from github
Published
2024-03-06 09:30
Modified
2025-02-14 18:30
Severity ?
5.5 (Medium) - CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
Details

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

IB/ipoib: Fix mcast list locking

Releasing the priv->lock while iterating the priv->multicast_list in ipoib_mcast_join_task() opens a window for ipoib_mcast_dev_flush() to remove the items while in the middle of iteration. If the mcast is removed while the lock was dropped, the for loop spins forever resulting in a hard lockup (as was reported on RHEL 4.18.0-372.75.1.el8_6 kernel):

Task A (kworker/u72:2 below)       | Task B (kworker/u72:0 below)
-----------------------------------+-----------------------------------
ipoib_mcast_join_task(work)        | ipoib_ib_dev_flush_light(work)
  spin_lock_irq(&priv->lock)       | __ipoib_ib_dev_flush(priv, ...)
  list_for_each_entry(mcast,       | ipoib_mcast_dev_flush(dev = priv->dev)
      &priv->multicast_list, list) |
    ipoib_mcast_join(dev, mcast)   |
      spin_unlock_irq(&priv->lock) |
                                   |   spin_lock_irqsave(&priv->lock, flags)
                                   |   list_for_each_entry_safe(mcast, tmcast,
                                   |                  &priv->multicast_list, list)
                                   |     list_del(&mcast->list);
                                   |     list_add_tail(&mcast->list, &remove_list)
                                   |   spin_unlock_irqrestore(&priv->lock, flags)
      spin_lock_irq(&priv->lock)   |
                                   |   ipoib_mcast_remove_list(&remove_list)

(Here, mcast is no longer on the | list_for_each_entry_safe(mcast, tmcast, priv->multicast_list and we keep | remove_list, list) spinning on the remove_list of | >>> wait_for_completion(&mcast->done) the other thread which is blocked | and the list is still valid on | it's stack.)

Fix this by keeping the lock held and changing to GFP_ATOMIC to prevent eventual sleeps. Unfortunately we could not reproduce the lockup and confirm this fix but based on the code review I think this fix should address such lockups.

crash> bc 31 PID: 747 TASK: ff1c6a1a007e8000 CPU: 31 COMMAND: "kworker/u72:2" -- [exception RIP: ipoib_mcast_join_task+0x1b1] RIP: ffffffffc0944ac1 RSP: ff646f199a8c7e00 RFLAGS: 00000002 RAX: 0000000000000000 RBX: ff1c6a1a04dc82f8 RCX: 0000000000000000 work (&priv->mcast_task{,.work}) RDX: ff1c6a192d60ac68 RSI: 0000000000000286 RDI: ff1c6a1a04dc8000 &mcast->list RBP: ff646f199a8c7e90 R8: ff1c699980019420 R9: ff1c6a1920c9a000 R10: ff646f199a8c7e00 R11: ff1c6a191a7d9800 R12: ff1c6a192d60ac00 mcast R13: ff1c6a1d82200000 R14: ff1c6a1a04dc8000 R15: ff1c6a1a04dc82d8 dev priv (&priv->lock) &priv->multicast_list (aka head) ORIG_RAX: ffffffffffffffff CS: 0010 SS: 0018 --- --- #5 [ff646f199a8c7e00] ipoib_mcast_join_task+0x1b1 at ffffffffc0944ac1 [ib_ipoib] #6 [ff646f199a8c7e98] process_one_work+0x1a7 at ffffffff9bf10967

crash> rx ff646f199a8c7e68 ff646f199a8c7e68: ff1c6a1a04dc82f8 <<< work = &priv->mcast_task.work

crash> list -hO ipoib_dev_priv.multicast_list ff1c6a1a04dc8000 (empty)

crash> ipoib_dev_priv.mcast_task.work.func,mcast_mutex.owner.counter ff1c6a1a04dc8000 mcast_task.work.func = 0xffffffffc0944910 , mcast_mutex.owner.counter = 0xff1c69998efec000

crash> b 8 PID: 8 TASK: ff1c69998efec000 CPU: 33 COMMAND: "kworker/u72:0" -- #3 [ff646f1980153d50] wait_for_completion+0x96 at ffffffff9c7d7646 #4 [ff646f1980153d90] ipoib_mcast_remove_list+0x56 at ffffffffc0944dc6 [ib_ipoib] #5 [ff646f1980153de8] ipoib_mcast_dev_flush+0x1a7 at ffffffffc09455a7 [ib_ipoib] #6 [ff646f1980153e58] __ipoib_ib_dev_flush+0x1a4 at ffffffffc09431a4 [ib_ipoib] #7 [ff ---truncated---

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{
  "affected": [],
  "aliases": [
    "CVE-2023-52587"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-667"
    ],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2024-03-06T07:15:07Z",
    "severity": "MODERATE"
  },
  "details": "In the Linux kernel, the following vulnerability has been resolved:\n\nIB/ipoib: Fix mcast list locking\n\nReleasing the `priv-\u003elock` while iterating the `priv-\u003emulticast_list` in\n`ipoib_mcast_join_task()` opens a window for `ipoib_mcast_dev_flush()` to\nremove the items while in the middle of iteration. If the mcast is removed\nwhile the lock was dropped, the for loop spins forever resulting in a hard\nlockup (as was reported on RHEL 4.18.0-372.75.1.el8_6 kernel):\n\n    Task A (kworker/u72:2 below)       | Task B (kworker/u72:0 below)\n    -----------------------------------+-----------------------------------\n    ipoib_mcast_join_task(work)        | ipoib_ib_dev_flush_light(work)\n      spin_lock_irq(\u0026priv-\u003elock)       | __ipoib_ib_dev_flush(priv, ...)\n      list_for_each_entry(mcast,       | ipoib_mcast_dev_flush(dev = priv-\u003edev)\n          \u0026priv-\u003emulticast_list, list) |\n        ipoib_mcast_join(dev, mcast)   |\n          spin_unlock_irq(\u0026priv-\u003elock) |\n                                       |   spin_lock_irqsave(\u0026priv-\u003elock, flags)\n                                       |   list_for_each_entry_safe(mcast, tmcast,\n                                       |                  \u0026priv-\u003emulticast_list, list)\n                                       |     list_del(\u0026mcast-\u003elist);\n                                       |     list_add_tail(\u0026mcast-\u003elist, \u0026remove_list)\n                                       |   spin_unlock_irqrestore(\u0026priv-\u003elock, flags)\n          spin_lock_irq(\u0026priv-\u003elock)   |\n                                       |   ipoib_mcast_remove_list(\u0026remove_list)\n   (Here, `mcast` is no longer on the  |     list_for_each_entry_safe(mcast, tmcast,\n    `priv-\u003emulticast_list` and we keep |                            remove_list, list)\n    spinning on the `remove_list` of   |  \u003e\u003e\u003e  wait_for_completion(\u0026mcast-\u003edone)\n    the other thread which is blocked  |\n    and the list is still valid on     |\n    it\u0027s stack.)\n\nFix this by keeping the lock held and changing to GFP_ATOMIC to prevent\neventual sleeps.\nUnfortunately we could not reproduce the lockup and confirm this fix but\nbased on the code review I think this fix should address such lockups.\n\ncrash\u003e bc 31\nPID: 747      TASK: ff1c6a1a007e8000  CPU: 31   COMMAND: \"kworker/u72:2\"\n--\n    [exception RIP: ipoib_mcast_join_task+0x1b1]\n    RIP: ffffffffc0944ac1  RSP: ff646f199a8c7e00  RFLAGS: 00000002\n    RAX: 0000000000000000  RBX: ff1c6a1a04dc82f8  RCX: 0000000000000000\n                                  work (\u0026priv-\u003emcast_task{,.work})\n    RDX: ff1c6a192d60ac68  RSI: 0000000000000286  RDI: ff1c6a1a04dc8000\n           \u0026mcast-\u003elist\n    RBP: ff646f199a8c7e90   R8: ff1c699980019420   R9: ff1c6a1920c9a000\n    R10: ff646f199a8c7e00  R11: ff1c6a191a7d9800  R12: ff1c6a192d60ac00\n                                                         mcast\n    R13: ff1c6a1d82200000  R14: ff1c6a1a04dc8000  R15: ff1c6a1a04dc82d8\n           dev                    priv (\u0026priv-\u003elock)     \u0026priv-\u003emulticast_list (aka head)\n    ORIG_RAX: ffffffffffffffff  CS: 0010  SS: 0018\n--- \u003cNMI exception stack\u003e ---\n #5 [ff646f199a8c7e00] ipoib_mcast_join_task+0x1b1 at ffffffffc0944ac1 [ib_ipoib]\n #6 [ff646f199a8c7e98] process_one_work+0x1a7 at ffffffff9bf10967\n\ncrash\u003e rx ff646f199a8c7e68\nff646f199a8c7e68:  ff1c6a1a04dc82f8 \u003c\u003c\u003c work = \u0026priv-\u003emcast_task.work\n\ncrash\u003e list -hO ipoib_dev_priv.multicast_list ff1c6a1a04dc8000\n(empty)\n\ncrash\u003e ipoib_dev_priv.mcast_task.work.func,mcast_mutex.owner.counter ff1c6a1a04dc8000\n  mcast_task.work.func = 0xffffffffc0944910 \u003cipoib_mcast_join_task\u003e,\n  mcast_mutex.owner.counter = 0xff1c69998efec000\n\ncrash\u003e b 8\nPID: 8        TASK: ff1c69998efec000  CPU: 33   COMMAND: \"kworker/u72:0\"\n--\n #3 [ff646f1980153d50] wait_for_completion+0x96 at ffffffff9c7d7646\n #4 [ff646f1980153d90] ipoib_mcast_remove_list+0x56 at ffffffffc0944dc6 [ib_ipoib]\n #5 [ff646f1980153de8] ipoib_mcast_dev_flush+0x1a7 at ffffffffc09455a7 [ib_ipoib]\n #6 [ff646f1980153e58] __ipoib_ib_dev_flush+0x1a4 at ffffffffc09431a4 [ib_ipoib]\n #7 [ff\n---truncated---",
  "id": "GHSA-hh6q-pgh2-779f",
  "modified": "2025-02-14T18:30:44Z",
  "published": "2024-03-06T09:30:27Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2023-52587"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/342258fb46d66c1b4c7e2c3717ac01e10c03cf18"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/4c8922ae8eb8dcc1e4b7d1059d97a8334288d825"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/4f973e211b3b1c6d36f7c6a19239d258856749f9"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/5108a2dc2db5630fb6cd58b8be80a0c134bc310a"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/615e3adc2042b7be4ad122a043fc9135e6342c90"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/7c7bd4d561e9dc6f5b7df9e184974915f6701a89"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/ac2630fd3c90ffec34a0bfc4d413668538b0e8f2"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/ed790bd0903ed3352ebf7f650d910f49b7319b34"
    },
    {
      "type": "WEB",
      "url": "https://lists.debian.org/debian-lts-announce/2024/06/msg00017.html"
    },
    {
      "type": "WEB",
      "url": "https://lists.debian.org/debian-lts-announce/2024/06/msg00020.html"
    }
  ],
  "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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