CVE-2024-47794

/// Technical description

In the Linux kernel, the following vulnerability has been resolved:

bpf: Prevent tailcall infinite loop caused by freplace

There is a potential infinite loop issue that can occur when using a

combination of tail calls and freplace.

In an upcoming selftest, the attach target for entry_freplace of

tailcall_freplace.c is subprog_tc of tc_bpf2bpf.c, while the tail call in

entry_freplace leads to entry_tc. This results in an infinite loop:

entry_tc -> subprog_tc -> entry_freplace --tailcall-> entry_tc.

The problem arises because the tail_call_cnt in entry_freplace resets to

zero each time entry_freplace is executed, causing the tail call mechanism

to never terminate, eventually leading to a kernel panic.

To fix this issue, the solution is twofold:

1. Prevent updating a program extended by an freplace program to a

prog_array map.

2. Prevent extending a program that is already part of a prog_array map

with an freplace program.

This ensures that:

* If a program or its subprogram

/// Remediation

Check the references section for vendor advisories, patches, and mitigation guidance. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.

/// References