In the Linux kernel, the following vulnerability has been resolved: bpf: Disallow bpf_skb_pull_data() for LWT_SEG6LOCAL An LWT_SEG6LOCAL program can invalidate its cached SRH with bpf_lwt_seg6_adjust_srh() and then call bpf_skb_pull_da…

Overview

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

bpf: Disallow bpf_skb_pull_data() for LWT_SEG6LOCAL

An LWT_SEG6LOCAL program can invalidate its cached SRH with bpf_lwt_seg6_adjust_srh() and then call bpf_skb_pull_data(). The latter may reallocate skb->head, leaving the per-CPU SRH pointer dangling. Post-program SRH validation then writes through that pointer.

Disallow bpf_skb_pull_data() for LWT_SEG6LOCAL programs so the verifier rejects this unsafe helper combination. Other LWT program types continue to expose the helper through lwt_out_func_proto().

Remediation

Refer to the linked advisories for vendor-supplied fixes and affected version ranges.