Description (CNA)
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 (CNA)
| Vendor / product | Versions |
|---|---|
| Linux / Linux | affected 259ee7754b6793af8bdd77f9ca818bc41cfe9541 before 314135b7bae9618a317874ae195272682cf2d5d4; affected 259ee7754b6793af8bdd77f9ca818bc41cfe9541 before 3ae93b316ca4b8b3c33798ef1d210355f2fb9318; affected 259ee7754b6793af8bdd77f9ca818bc41cfe9541 before 84256e00eeca73c529fc6196e478cc89b8098157; affected 259ee7754b6793af8bdd77f9ca818bc41cfe9541 before 6ebcd021c92b8e4b904552e4d87283032100796d; affected 3d95c52d789ca99e344061d7f6dadb2519adbcf5; affected fba904d68c8bbfcc89c2210cfcb2351be90bc3e5; affected 5.2.19 before 5.3; affected 5.3.4 before 5.4 |
| Linux / Linux | affected 5.4; unaffected 0 before 5.4; unaffected 5.15.127 through 5.15.*; unaffected 6.1.46 through 6.1.*; unaffected 6.4.11 through 6.4.*; unaffected 6.5 through * |
CWE
No CWE identifiers supplied.