Overview
About vulnerability
In the Linux kernel, the following vulnerability has been resolved:
fs/ntfs3: bound attr_off in UpdateResidentValue against data_off
In do_action()’s UpdateResidentValue case (fslog.c:3307), lrh->attr_off and lrh->redo_len come from the on-disk LRH. When they satisfy aoff + dlen < attr->res.data_off, the assignment
attr->res.data_size = cpu_to_le32(aoff + dlen - data_off);
underflows to ~4 GiB (e.g. 0xFFFFFFF9 when aoff=0x10, dlen=1, data_off=0x18). Subsequent code that reads attr->res.data_size to walk the resident attribute payload would then read up to 4 GiB past the 1024-byte MFT record allocation.
The existing mi_enum_attr() defense in fs/ntfs3/record.c:287 catches the corrupted data_size on the next attribute walk and fails the mount, but only on the path that walks all attributes. A read site that picks an attribute by name and reads its data_size without re-validating is not covered. Validate aoff against data_off and asize at the source.
Reproduced under UML+KASAN on mainline 8d90b09e6741 via pr_warn-only probe: with aoff=0x10 and data_off=0x18, the post-assignment data_size is 0xfffffff9 (mount then fails at -22 from mi_enum_attr).
[[email protected]: clang-formatted the changes]
Details
- Affected product:
- Debian 10 ELS , Ubuntu 20.04 ELS
- Affected packages:
- linux @ 4.19.0 (+1 more)
Fixes
KernelCare state
Live-patch status from KernelCare for each operating system.
| Operating system | Status | Covered kernels |
|---|---|---|
| Amazon Linux 2023 | Planned | — |
| Debian 12 | Will Not Fix |
42 kernels
|
| Debian 13 | Released |
13 kernels
|
| Proxmox VE 7 5.15 | In Rollout |
47 kernels
|
| Ubuntu 20.04 HWE AWS | Released |
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 | Released |
2 kernels
|