CVE-2024-58237

/// Technical description

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

bpf: consider that tail calls invalidate packet pointers

Tail-called programs could execute any of the helpers that invalidate

packet pointers. Hence, conservatively assume that each tail call

invalidates packet pointers.

Making the change in bpf_helper_changes_pkt_data() automatically makes

use of check_cfg() logic that computes 'changes_pkt_data' effect for

global sub-programs, such that the following program could be

rejected:

int tail_call(struct __sk_buff *sk)

{

bpf_tail_call_static(sk, &jmp_table, 0);

return 0;

}

SEC("tc")

int not_safe(struct __sk_buff *sk)

{

int *p = (void *)(long)sk->data;

... make p valid ...

tail_call(sk);

*p = 42; /* this is unsafe */

...

}

The tc_bpf2bpf.c:subprog_tc() needs change: mark it as a function that

can invalidate packet pointers. Otherwise, it can't be freplaced with

tailcall_freplace.c:entry_freplace() that doe

/// 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