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 does a tail call.

Classification

CVE ID: CVE-2024-58237

Affected Products

Vendor: Linux

Product: Linux

Exploit Prediction Scoring System (EPSS)

EPSS Score: 0.02% (probability of being exploited)

EPSS Percentile: 4.36% (scored less or equal to compared to others)

EPSS Date: 2025-06-03 (when was this score calculated)

References

https://nvd.nist.gov/vuln/detail/CVE-2024-58237
https://git.kernel.org/stable/c/1c2244437f9ad3dd91215f920401a14f2542dbfc
https://git.kernel.org/stable/c/1a4607ffba35bf2a630aab299e34dd3f6e658d70

Timeline