ghsa-2244-8r8j-955v
Vulnerability from github
In the Linux kernel, the following vulnerability has been resolved:
btrfs: reject invalid reloc tree root keys with stack dump
[BUG] Syzbot reported a crash that an ASSERT() got triggered inside prepare_to_merge().
That ASSERT() makes sure the reloc tree is properly pointed back by its subvolume tree.
[CAUSE] After more debugging output, it turns out we had an invalid reloc tree:
BTRFS error (device loop1): reloc tree mismatch, root 8 has no reloc root, expect reloc root key (-8, 132, 8) gen 17
Note the above root key is (TREE_RELOC_OBJECTID, ROOT_ITEM, QUOTA_TREE_OBJECTID), meaning it's a reloc tree for quota tree.
But reloc trees can only exist for subvolumes, as for non-subvolume trees, we just COW the involved tree block, no need to create a reloc tree since those tree blocks won't be shared with other trees.
Only subvolumes tree can share tree blocks with other trees (thus they have BTRFS_ROOT_SHAREABLE flag).
Thus this new debug output proves my previous assumption that corrupted on-disk data can trigger that ASSERT().
[FIX] Besides the dedicated fix and the graceful exit, also let tree-checker to check such root keys, to make sure reloc trees can only exist for subvolumes.
{
"affected": [],
"aliases": [
"CVE-2023-53618"
],
"database_specific": {
"cwe_ids": [],
"github_reviewed": false,
"github_reviewed_at": null,
"nvd_published_at": "2025-10-07T16:15:44Z",
"severity": null
},
"details": "In the Linux kernel, the following vulnerability has been resolved:\n\nbtrfs: reject invalid reloc tree root keys with stack dump\n\n[BUG]\nSyzbot reported a crash that an ASSERT() got triggered inside\nprepare_to_merge().\n\nThat ASSERT() makes sure the reloc tree is properly pointed back by its\nsubvolume tree.\n\n[CAUSE]\nAfter more debugging output, it turns out we had an invalid reloc tree:\n\n BTRFS error (device loop1): reloc tree mismatch, root 8 has no reloc root, expect reloc root key (-8, 132, 8) gen 17\n\nNote the above root key is (TREE_RELOC_OBJECTID, ROOT_ITEM,\nQUOTA_TREE_OBJECTID), meaning it\u0027s a reloc tree for quota tree.\n\nBut reloc trees can only exist for subvolumes, as for non-subvolume\ntrees, we just COW the involved tree block, no need to create a reloc\ntree since those tree blocks won\u0027t be shared with other trees.\n\nOnly subvolumes tree can share tree blocks with other trees (thus they\nhave BTRFS_ROOT_SHAREABLE flag).\n\nThus this new debug output proves my previous assumption that corrupted\non-disk data can trigger that ASSERT().\n\n[FIX]\nBesides the dedicated fix and the graceful exit, also let tree-checker to\ncheck such root keys, to make sure reloc trees can only exist for subvolumes.",
"id": "GHSA-2244-8r8j-955v",
"modified": "2025-10-07T18:31:09Z",
"published": "2025-10-07T18:31:09Z",
"references": [
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2023-53618"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/314135b7bae9618a317874ae195272682cf2d5d4"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/3ae93b316ca4b8b3c33798ef1d210355f2fb9318"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/6ebcd021c92b8e4b904552e4d87283032100796d"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/84256e00eeca73c529fc6196e478cc89b8098157"
}
],
"schema_version": "1.4.0",
"severity": []
}
Sightings
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