CVE-2022-50069

Technical Description

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

BPF: Fix potential bad pointer dereference in bpf_sys_bpf()

The bpf_sys_bpf() helper function allows an eBPF program to load another

eBPF program from within the kernel. In this case the argument union

bpf_attr pointer (as well as the insns and license pointers inside) is a

kernel address instead of a userspace address (which is the case of a

usual bpf() syscall). To make the memory copying process in the syscall

work in both cases, bpfptr_t was introduced to wrap around the pointer

and distinguish its origin. Specifically, when copying memory contents

from a bpfptr_t, a copy_from_user() is performed in case of a userspace

address and a memcpy() is performed for a kernel address.

This can lead to problems because the in-kernel pointer is never checked

for validity. The problem happens when an eBPF syscall program tries to

call bpf_sys_bpf() to load a program but provides a bad insns pointer --

say 0xdeadbeef -- in t

Remediation

Check the references section for vendor advisories and patches from linux. Update linux_kernel to the latest patched version. 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.

Affected Products

References