ghsa-h4gq-9hmg-w96x
Vulnerability from github
Published
2025-09-15 15:31
Modified
2025-09-15 15:31
Details

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

tracing: Fix reading strings from synthetic events

The follow commands caused a crash:

# cd /sys/kernel/tracing # echo 's:open char file[]' > dynamic_events # echo 'hist:keys=common_pid:file=filename:onchange($file).trace(open,$file)' > events/syscalls/sys_enter_openat/trigger' # echo 1 > events/synthetic/open/enable

BOOM!

The problem is that the synthetic event field "char file[]" will read the value given to it as a string without any memory checks to make sure the address is valid. The above example will pass in the user space address and the sythetic event code will happily call strlen() on it and then strscpy() where either one will cause an oops when accessing user space addresses.

Use the helper functions from trace_kprobe and trace_eprobe that can read strings safely (and actually succeed when the address is from user space and the memory is mapped in).

Now the above can show:

 packagekitd-1721    [000] ...2.   104.597170: open: file=/usr/lib/rpm/fileattrs/cmake.attr
in:imjournal-978     [006] ...2.   104.599642: open: file=/var/lib/rsyslog/imjournal.state.tmp
 packagekitd-1721    [000] ...2.   104.626308: open: file=/usr/lib/rpm/fileattrs/debuginfo.attr
Show details on source website

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{
  "affected": [],
  "aliases": [
    "CVE-2022-50255"
  ],
  "database_specific": {
    "cwe_ids": [],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2025-09-15T14:15:36Z",
    "severity": null
  },
  "details": "In the Linux kernel, the following vulnerability has been resolved:\n\ntracing: Fix reading strings from synthetic events\n\nThe follow commands caused a crash:\n\n  # cd /sys/kernel/tracing\n  # echo \u0027s:open char file[]\u0027 \u003e dynamic_events\n  # echo \u0027hist:keys=common_pid:file=filename:onchange($file).trace(open,$file)\u0027 \u003e events/syscalls/sys_enter_openat/trigger\u0027\n  # echo 1 \u003e events/synthetic/open/enable\n\nBOOM!\n\nThe problem is that the synthetic event field \"char file[]\" will read\nthe value given to it as a string without any memory checks to make sure\nthe address is valid. The above example will pass in the user space\naddress and the sythetic event code will happily call strlen() on it\nand then strscpy() where either one will cause an oops when accessing\nuser space addresses.\n\nUse the helper functions from trace_kprobe and trace_eprobe that can\nread strings safely (and actually succeed when the address is from user\nspace and the memory is mapped in).\n\nNow the above can show:\n\n     packagekitd-1721    [000] ...2.   104.597170: open: file=/usr/lib/rpm/fileattrs/cmake.attr\n    in:imjournal-978     [006] ...2.   104.599642: open: file=/var/lib/rsyslog/imjournal.state.tmp\n     packagekitd-1721    [000] ...2.   104.626308: open: file=/usr/lib/rpm/fileattrs/debuginfo.attr",
  "id": "GHSA-h4gq-9hmg-w96x",
  "modified": "2025-09-15T15:31:23Z",
  "published": "2025-09-15T15:31:22Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2022-50255"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/0934ae9977c27133449b6dd8c6213970e7eece38"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/149198d0b884e4606ed1d29b330c70016d878276"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/d9c79fbcbdb6cb10c07c85040eaf615180b26c48"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/f8bae1853196b52ede50950387f5b48cf83b9815"
    }
  ],
  "schema_version": "1.4.0",
  "severity": []
}


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