ghsa-6297-42q7-j694
Vulnerability from github
In the Linux kernel, the following vulnerability has been resolved:
sch_htb: fix refcount leak in htb_parent_to_leaf_offload
The commit ae81feb7338c ("sch_htb: fix null pointer dereference on a null new_q") fixes a NULL pointer dereference bug, but it is not correct.
Because htb_graft_helper properly handles the case when new_q is NULL, and after the previous patch by skipping this call which creates an inconsistency : dev_queue->qdisc will still point to the old qdisc, but cl->parent->leaf.q will point to the new one (which will be noop_qdisc, because new_q was NULL). The code is based on an assumption that these two pointers are the same, so it can lead to refcount leaks.
The correct fix is to add a NULL pointer check to protect qdisc_refcount_inc inside htb_parent_to_leaf_offload.
{
"affected": [],
"aliases": [
"CVE-2021-47125"
],
"database_specific": {
"cwe_ids": [],
"github_reviewed": false,
"github_reviewed_at": null,
"nvd_published_at": "2024-03-15T21:15:07Z",
"severity": null
},
"details": "In the Linux kernel, the following vulnerability has been resolved:\n\nsch_htb: fix refcount leak in htb_parent_to_leaf_offload\n\nThe commit ae81feb7338c (\"sch_htb: fix null pointer dereference\non a null new_q\") fixes a NULL pointer dereference bug, but it\nis not correct.\n\nBecause htb_graft_helper properly handles the case when new_q\nis NULL, and after the previous patch by skipping this call\nwhich creates an inconsistency : dev_queue-\u003eqdisc will still\npoint to the old qdisc, but cl-\u003eparent-\u003eleaf.q will point to\nthe new one (which will be noop_qdisc, because new_q was NULL).\nThe code is based on an assumption that these two pointers are\nthe same, so it can lead to refcount leaks.\n\nThe correct fix is to add a NULL pointer check to protect\nqdisc_refcount_inc inside htb_parent_to_leaf_offload.",
"id": "GHSA-6297-42q7-j694",
"modified": "2024-03-15T21:30:44Z",
"published": "2024-03-15T21:30:44Z",
"references": [
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2021-47125"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/2411c02d03892a5057499f8102d0cc1e0f852416"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/944d671d5faa0d78980a3da5c0f04960ef1ad893"
}
],
"schema_version": "1.4.0",
"severity": []
}
Sightings
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