vulnerability

Debian: CVE-2024-58237: linux -- security update

Severity
5
CVSS
(AV:L/AC:L/Au:S/C:N/I:N/A:C)
Published
May 5, 2025
Added
May 15, 2025
Modified
May 27, 2025

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.

Solution

no-fix-debian-deb-package
Title
NEW

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