Overview
About vulnerability
In the Linux kernel, the following vulnerability has been resolved:
dm-verity: fix buffer overflow in FEC calculation
There’s a buffer overflow in dm-verity-fec:
if (neras && *neras <= v->fec->roots) fio->erasures[(*neras)++] = i;
This allows *neras to reach roots + 1 (the post-increment pushes it past roots). This value is then passed as no_eras to decode_rs8(). Inside the RS decoder (lib/reed_solomon/decode_rs.c:113-121), the erasure locator polynomial loop writes lambda[j] where j can reach nroots + 1 — one element past the end of lambda[] (which is sized nroots + 1, valid indices 0..nroots). The out-of-bounds write lands on syn[0], corrupting the syndrome buffer.
Details
- Affected product:
- AlmaLinux 9.2 ESU , Amazon Linux 2 ELS , CentOS 8.4 ELS , CentOS 8.5 ELS , CentOS Stream 8 ELS , Debian 10 ELS , Debian 11 ELS , Oracle Linux 7 ELS , TuxCare 9.6 ESU , TuxCare 9.8 ESU , Ubuntu 16.04 ELS , Ubuntu 18.04 ELS , Ubuntu 20.04 ELS
- Affected packages:
- linux @ 4.19.0 (+12 more)
Fixes
KernelCare state
Live-patch status from KernelCare for each operating system.
| Operating system | Status | Covered kernels |
|---|---|---|
| AlmaLinux 9 | Released |
131 kernels
|
| AlmaLinux 9.2 ESU | Planned | — |
| AlmaLinux 9.6 ESU | Planned | — |
| Oracle Linux 9 | Released |
130 kernels
|
| RHEL 10 | Planned | — |
| RHEL 8 | Planned | — |
| RHEL 9 | Released |
129 kernels
|
| Rocky Linux 9 | Released |
106 kernels
|
| Ubuntu 26.04 | Planned | — |