In the Linux kernel, the following vulnerability has been resolved:
erofs: fix UAF issue for file-backed mounts w/ directio option
[ 9.269940][ T3222] Call trace: [ 9.269948][ T3222] ext4_file_read_iter+0xac/0x108 [ 9.269979][ T3222] vfs_iocb_iter_read+0xac/0x198 [ 9.269993][ T3222] erofs_fileio_rq_submit+0x12c/0x180 [ 9.270008][ T3222] erofs_fileio_submit_bio+0x14/0x24 [ 9.270030][ T3222] z_erofs_runqueue+0x834/0x8ac [ 9.270054][ T3222] z_erofs_read_folio+0x120/0x220 [ 9.270083][ T3222] filemap_read_folio+0x60/0x120 [ 9.270102][ T3222] filemap_fault+0xcac/0x1060 [ 9.270119][ T3222] do_pte_missing+0x2d8/0x1554 [ 9.270131][ T3222] handle_mm_fault+0x5ec/0x70c [ 9.270142][ T3222] do_page_fault+0x178/0x88c [ 9.270167][ T3222] do_translation_fault+0x38/0x54 [ 9.270183][ T3222] do_mem_abort+0x54/0xac [ 9.270208][ T3222] el0_da+0x44/0x7c [ 9.270227][ T3222] el0t_64_sync_handler+0x5c/0xf4 [ 9.270253][ T3222] el0t_64_sync+0x1bc/0x1c0
EROFS may encounter above panic when enabling file-backed mount w/ directio mount option, the root cause is it may suffer UAF in below race condition:
- z_erofs_read_folio wq s_dio_done_wq - z_erofs_runqueue - erofs_fileio_submit_bio - erofs_fileio_rq_submit - vfs_iocb_iter_read - ext4_file_read_iter - ext4_dio_read_iter - iomap_dio_rw : bio was submitted and return -EIOCBQUEUED - dio_aio_complete_work - dio_complete - dio->iocb->ki_complete (erofs_fileio_ki_complete()) - kfree(rq) : it frees iocb, iocb.ki_filp can be UAF in file_accessed(). - file_accessed : access NULL file point
Introduce a reference count in struct erofs_fileio_rq, and initialize it as two, both erofs_fileio_ki_complete() and erofs_fileio_rq_submit() will decrease reference count, the last one decreasing the reference count to zero will free rq.
CVSS Details
- CVSS 3.1 Base Score: 7.8
- CVSS 3.1 Vector: (CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H)
Covered by Rapid7
| Product | Vendor Advisory | Solution File | Added | Published |
|---|---|---|---|---|
| Amazon_linux_2023 | — | Upgrade kernel6.12-toolsUpgrade kernel6.12-tools-debuginfoUpgrade perf6.12-debuginfoUpgrade python3-perf6.12-debuginfoUpgrade bpftool6.12-debuginfoUpgrade bpftool6.12Upgrade kernel6.12-modules-extraUpgrade kernel6.12-debuginfoUpgrade kernel6.12-libbpf-staticUpgrade kernel6.12-debuginfo-common-aarch64Upgrade kernel6.12-libbpf-develUpgrade kernel6.12-libbpfUpgrade kernel6.12-tools-develUpgrade kernel-livepatch-6.12.73-95.123Upgrade kernel6.12-debuginfo-common-x86_64Upgrade kernel6.12-headersUpgrade python3-perf6.12Upgrade kernel6.12-develUpgrade perf6.12Upgrade kernel6.12-modules-extra-commonUpgrade kernel6.12-libbpf-debuginfoUpgrade kernel6.12 | Mar 27, 2026 | Feb 18, 2026 |
| Debian | — | Upgrade linux | Jul 23, 2026 | Jul 23, 2026 |
| Oracle_linux | — | Upgrade kernel-uek | Mar 25, 2026 | Feb 18, 2026 |
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