DocumentationOverview
About vulnerability
In the Linux kernel, the following vulnerability has been resolved:
bpf: reject BPF_PSEUDO_FUNC reference to the main program
fixups.c:jit_subprogs() rewrites BPF_PSEUDO_FUNC loads to contain real function addresses. This function is invoked from bpf_jit_subprogs() only when env->subprog_cnt > 1. Meaning that for any program like below:
int main(void *ctx) { void *ptr = main; … bpf_timer_set_callback(…, ptr); … }
The ‘ptr’ won’t be ever converted to contain an address. In combination with e.g. bpf_timer_set_callback() this would lead to a function call at a bogus address.
Instead of complicating the implementation, just assume that no useful program needs main to be a sync or async callback and reject BPF_PSEUDO_FUNC loads for the main subprogram.
Details
- Affected product:
- AlmaLinux 9.2 ESU , CentOS 8.4 ELS , CentOS 8.5 ELS , CentOS Stream 8 ELS , TuxCare 9.6 ESU , TuxCare 9.8 ESU
- Affected packages:
- kernel @ 5.14.0 (+5 more)
Fixes
KernelCare state
Live-patch status from KernelCare for each operating system.
| Operating system | Status | Covered kernels |
|---|---|---|
| AlmaLinux 9.2 ESU | In Rollout |
36 kernels
|
| Debian 12 | Planned | — |
| Debian 13 | Planned | — |