ghsa-3wc5-j3q5-m2xc
Vulnerability from github
Published
2025-10-07 18:31
Modified
2025-10-07 18:31
Details

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

md: don't dereference mddev after export_rdev()

Except for initial reference, mddev->kobject is referenced by rdev->kobject, and if the last rdev is freed, there is no guarantee that mddev is still valid. Hence mddev should not be used anymore after export_rdev().

This problem can be triggered by following test for mdadm at very low rate:

New file: mdadm/tests/23rdev-lifetime

devname=${dev0##*/} devt=cat /sys/block/$devname/dev pid="" runtime=2

clean_up_test() { pill -9 $pid echo clear > /sys/block/md0/md/array_state }

trap 'clean_up_test' EXIT

add_by_sysfs() { while true; do echo $devt > /sys/block/md0/md/new_dev done }

remove_by_sysfs(){ while true; do echo remove > /sys/block/md0/md/dev-${devname}/state done }

echo md0 > /sys/module/md_mod/parameters/new_array || die "create md0 failed"

add_by_sysfs & pid="$pid $!"

remove_by_sysfs & pid="$pid $!"

sleep $runtime exit 0

Test cmd:

./test --save-logs --logdir=/tmp/ --keep-going --dev=loop --tests=23rdev-lifetime

Test result:

general protection fault, probably for non-canonical address 0x6b6b6b6b6b6b6bcb: 0000 [#4] PREEMPT SMP CPU: 0 PID: 1292 Comm: test Tainted: G D W 6.5.0-rc2-00121-g01e55c376936 #562 RIP: 0010:md_wakeup_thread+0x9e/0x320 [md_mod] Call Trace: mddev_unlock+0x1b6/0x310 [md_mod] rdev_attr_store+0xec/0x190 [md_mod] sysfs_kf_write+0x52/0x70 kernfs_fop_write_iter+0x19a/0x2a0 vfs_write+0x3b5/0x770 ksys_write+0x74/0x150 __x64_sys_write+0x22/0x30 do_syscall_64+0x40/0x90 entry_SYSCALL_64_after_hwframe+0x63/0xcd

Fix this problem by don't dereference mddev after export_rdev().

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{
  "affected": [],
  "aliases": [
    "CVE-2023-53665"
  ],
  "database_specific": {
    "cwe_ids": [],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2025-10-07T16:15:50Z",
    "severity": null
  },
  "details": "In the Linux kernel, the following vulnerability has been resolved:\n\nmd: don\u0027t dereference mddev after export_rdev()\n\nExcept for initial reference, mddev-\u003ekobject is referenced by\nrdev-\u003ekobject, and if the last rdev is freed, there is no guarantee that\nmddev is still valid. Hence mddev should not be used anymore after\nexport_rdev().\n\nThis problem can be triggered by following test for mdadm at very\nlow rate:\n\nNew file: mdadm/tests/23rdev-lifetime\n\ndevname=${dev0##*/}\ndevt=`cat /sys/block/$devname/dev`\npid=\"\"\nruntime=2\n\nclean_up_test() {\n        pill -9 $pid\n        echo clear \u003e /sys/block/md0/md/array_state\n}\n\ntrap \u0027clean_up_test\u0027 EXIT\n\nadd_by_sysfs() {\n        while true; do\n                echo $devt \u003e /sys/block/md0/md/new_dev\n        done\n}\n\nremove_by_sysfs(){\n        while true; do\n                echo remove \u003e /sys/block/md0/md/dev-${devname}/state\n        done\n}\n\necho md0 \u003e /sys/module/md_mod/parameters/new_array || die \"create md0 failed\"\n\nadd_by_sysfs \u0026\npid=\"$pid $!\"\n\nremove_by_sysfs \u0026\npid=\"$pid $!\"\n\nsleep $runtime\nexit 0\n\nTest cmd:\n\n./test --save-logs --logdir=/tmp/ --keep-going --dev=loop --tests=23rdev-lifetime\n\nTest result:\n\ngeneral protection fault, probably for non-canonical address 0x6b6b6b6b6b6b6bcb: 0000 [#4] PREEMPT SMP\nCPU: 0 PID: 1292 Comm: test Tainted: G      D W          6.5.0-rc2-00121-g01e55c376936 #562\nRIP: 0010:md_wakeup_thread+0x9e/0x320 [md_mod]\nCall Trace:\n \u003cTASK\u003e\n mddev_unlock+0x1b6/0x310 [md_mod]\n rdev_attr_store+0xec/0x190 [md_mod]\n sysfs_kf_write+0x52/0x70\n kernfs_fop_write_iter+0x19a/0x2a0\n vfs_write+0x3b5/0x770\n ksys_write+0x74/0x150\n __x64_sys_write+0x22/0x30\n do_syscall_64+0x40/0x90\n entry_SYSCALL_64_after_hwframe+0x63/0xcd\n\nFix this problem by don\u0027t dereference mddev after export_rdev().",
  "id": "GHSA-3wc5-j3q5-m2xc",
  "modified": "2025-10-07T18:31:10Z",
  "published": "2025-10-07T18:31:10Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2023-53665"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/7deac114be5fb25a4e865212ed0feaf5f85f2a28"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/ad430ad0669d2757377373390d68e1454fc7a344"
    }
  ],
  "schema_version": "1.4.0",
  "severity": []
}


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