Overview
About vulnerability
In the Linux kernel, the following vulnerability has been resolved:
jbd2: fix integer underflow in jbd2_journal_initialize_fast_commit()
jbd2_journal_initialize_fast_commit() validates journal capacity by checking (journal->j_last - num_fc_blks < JBD2_MIN_JOURNAL_BLOCKS). Both j_last and num_fc_blks are unsigned, so when num_fc_blks exceeds j_last the subtraction wraps to a large value, bypassing the bounds check.
The resulting underflow corrupts j_last, j_fc_first, and j_free, leading to journal abort.
Fix by checking num_fc_blks against j_last before the subtraction, returning -EFSCORRUPTED.
Details
- Affected product:
- AlmaLinux 9.2 ESU , Amazon Linux 2 ELS , Debian 10 ELS , Debian 11 ELS , TuxCare 9.6 ESU , TuxCare 9.8 ESU , Ubuntu 20.04 ELS
- Affected packages:
- linux @ 4.19.0 (+6 more)
Fixes
KernelCare state
Live-patch status from KernelCare for each operating system.
| Operating system | Status | Covered kernels |
|---|---|---|
| Amazon Linux 2023 | Planned | — |
| Debian 12 | Released |
42 kernels
|
| Debian 13 | Released |
13 kernels
|
| Oracle Linux 8 UEK 7 | Released |
112 kernels
|
| Oracle Linux 9 UEK 7 | Released |
112 kernels
|
| Proxmox VE 7 5.15 | In Rollout |
47 kernels
|
| Ubuntu 20.04 HWE AWS | In Rollout |
57 kernels
|
| Ubuntu 22.04 | Released |
102 kernels
|
| Ubuntu 22.04 AWS | Released |
93 kernels
|
| Ubuntu 22.04 Azure | Released |
83 kernels
|
| Ubuntu 24.04 | Planned | — |
| Ubuntu 24.04 AWS | Planned | — |
| Ubuntu 26.04 | In Rollout |
2 kernels
|