GHSA-W9WH-Q8V9-3RWF
Vulnerability from github – Published: 2025-05-01 15:31 – Updated: 2025-05-07 15:31In the Linux kernel, the following vulnerability has been resolved:
ring-buffer: Check for NULL cpu_buffer in ring_buffer_wake_waiters()
On some machines the number of listed CPUs may be bigger than the actual CPUs that exist. The tracing subsystem allocates a per_cpu directory with access to the per CPU ring buffer via a cpuX file. But to save space, the ring buffer will only allocate buffers for online CPUs, even though the CPU array will be as big as the nr_cpu_ids.
With the addition of waking waiters on the ring buffer when closing the file, the ring_buffer_wake_waiters() now needs to make sure that the buffer is allocated (with the irq_work allocated with it) before trying to wake waiters, as it will cause a NULL pointer dereference.
While debugging this, I added a NULL check for the buffer itself (which is OK to do), and also NULL pointer checks against buffer->buffers (which is not fine, and will WARN) as well as making sure the CPU number passed in is within the nr_cpu_ids (which is also not fine if it isn't).
Bugzilla: https://bugzilla.opensuse.org/show_bug.cgi?id=1204705
{
"affected": [],
"aliases": [
"CVE-2022-49889"
],
"database_specific": {
"cwe_ids": [
"CWE-476"
],
"github_reviewed": false,
"github_reviewed_at": null,
"nvd_published_at": "2025-05-01T15:16:13Z",
"severity": "MODERATE"
},
"details": "In the Linux kernel, the following vulnerability has been resolved:\n\nring-buffer: Check for NULL cpu_buffer in ring_buffer_wake_waiters()\n\nOn some machines the number of listed CPUs may be bigger than the actual\nCPUs that exist. The tracing subsystem allocates a per_cpu directory with\naccess to the per CPU ring buffer via a cpuX file. But to save space, the\nring buffer will only allocate buffers for online CPUs, even though the\nCPU array will be as big as the nr_cpu_ids.\n\nWith the addition of waking waiters on the ring buffer when closing the\nfile, the ring_buffer_wake_waiters() now needs to make sure that the\nbuffer is allocated (with the irq_work allocated with it) before trying to\nwake waiters, as it will cause a NULL pointer dereference.\n\nWhile debugging this, I added a NULL check for the buffer itself (which is\nOK to do), and also NULL pointer checks against buffer-\u003ebuffers (which is\nnot fine, and will WARN) as well as making sure the CPU number passed in\nis within the nr_cpu_ids (which is also not fine if it isn\u0027t).\n\n\nBugzilla: https://bugzilla.opensuse.org/show_bug.cgi?id=1204705",
"id": "GHSA-w9wh-q8v9-3rwf",
"modified": "2025-05-07T15:31:26Z",
"published": "2025-05-01T15:31:51Z",
"references": [
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2022-49889"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/49ca992f6e50d0f46ec9608f44e011cf3121f389"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/7433632c9ff68a991bd0bc38cabf354e9d2de410"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/b5074df412bf3df9d6ce096b6fa03eb1082d05c9"
}
],
"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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