fkie_cve-2023-53618
Vulnerability from fkie_nvd
Published
2025-10-07 16:15
Modified
2025-10-08 19:38
Severity ?
Summary
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.
References
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/314135b7bae9618a317874ae195272682cf2d5d4
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/3ae93b316ca4b8b3c33798ef1d210355f2fb9318
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/6ebcd021c92b8e4b904552e4d87283032100796d
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/84256e00eeca73c529fc6196e478cc89b8098157
Impacted products
Vendor Product Version


To clipboard 

{
  "cveTags": [],
  "descriptions": [
    {
      "lang": "en",
      "value": "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": "CVE-2023-53618",
  "lastModified": "2025-10-08T19:38:32.610",
  "metrics": {},
  "published": "2025-10-07T16:15:44.297",
  "references": [
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/314135b7bae9618a317874ae195272682cf2d5d4"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/3ae93b316ca4b8b3c33798ef1d210355f2fb9318"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/6ebcd021c92b8e4b904552e4d87283032100796d"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/84256e00eeca73c529fc6196e478cc89b8098157"
    }
  ],
  "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
  "vulnStatus": "Awaiting Analysis"
}


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